silicone coating

What is silicone material used for?

Silicon is one element that is very abundant and is top second on Earth,which is 25.8% on the earth surface. Most people knows the function of metal silicone. silicon semiconductor materials have boosted the development of modern electronic industry. In addition, silicate-based inorganic silicon compounds are widely existing in nature, which is very convenient to use. Over thousands of years, people use silicone related material to produce cement, glass, ceramics and other products.

Inorganic silicone compounds have been applied very early to produce products such as glass and ceramics. But organic silicone  compounds do not exist in nature. It is mainly by synthesis, and were synthesized in around 50 years ago. Since the industrialization in 1940s, organic silicone compounds have developed rapidly.

Organic silicon, also known as silicone or siloxane, is siloxane organic polymer  cross-linked from silicon and oxygen. It has good characteristics  with excellent heat resistance, cold resistance,  oxidation resistance and electrical insulation, which are not available from other general organic polymers. Among the organic silicon compounds, polysiloxane has wide application with its special structural characteristics.

 

silicone materials are mainly divided into silicone oil(Dimethicone/PDMS/ Dimethyl Silicone Fluid, silicone defoamer, silicone leveling agent, polyether modified silicone oil), silicone rubber, silicone resin and silane coupling agent etc. And there are various silicone material related products. For example, Dow Corning has more than 4000 kinds of types of silicone materials.  If converted into polysiloxane, the total global consumption of various silicone products is about 650,000 tons, which accounts for 0.65% of the global total output of different synthetic resin products. In addition, the sales amount of silicone products are as high as $6.5 billion, which accounts for 7% of the global  total sales amount of different synthetic resin products.

silicone can be widely used in the production of silicone fluid, agriculture silicone adjuvant, advanced lubricants, adhesives, dielectric oil, adhesives, paint, antifoaming agents, gasket, seals as well as spare parts for rocket and missile. In recent years, the silicone material has been applied gradually from military or national defense to people’s daily life. Products for daily application include conductive buttons for computer, mobile phones and electrical keyboard; contact lens, swimming glasses and swimming caps; nipple; silicone sealants for curtain wall; finishing agent for high end leather or fabric; silicone oil for shampoo. Silicone material has become a necessary part in people’s daily life. It also becomes a new chemical material with development  on its rise.

silicone coating

With the prospects of silicone material, many developed countries put silicone materials as one of the most important new materials for the key development of the new century. Organic silicon is new material itself, meanwhile it is also the new material foundation for the development of related industrial areas. Given the changing nature of organic silicon material and with the characteristics of  small volume wide application, it is reputed as the catalyst for scientific and technological development. In the silicone industry, only a few upstream enterprises are in large scale and most of them are small and medium-sized private enterprises engaged in the production of consuming products and additives.

 

Main silicone products and their applications

Silicone materials are mainly grouped into four categories: silicone oil with its secondary processing products, silicone rubber, silicone resin and silane coupling agent. It is known as industrial MSG as silicone products have the properties of electrical insulation, corrosion resistance, radiation resistance, flame resistance, high and low temperature resistance as well as physiological inertia. They are widely applied in building materials, electronic and electrical products, light industry, textile, plastics, rubber, machinery, transportation, medical and other industries. At present, the global annual production capacity of silicone products has reached more than 1.2 million tons. There are around 5,000 to 10,000 products, and the total market sales can reach US $7 billion.

Among the more than 10,000 kinds of silicone products can be roughly divided into three categories: raw materials, intermediates and  products. Silicone monomer refers to organic silicon polymer monomer synthesized by organic chlorosilane, such as raw materials like benzene chlorosilane, methyl chlorosilane, vinyl chlorosilane and some other materials.

Organic silicon intermediates refer to line type or ring type siloxane oligomers,  such as octaethylcyclotetrasilxane (D4), hexamethyldisilxane (MM),  dimethylcyclosilane mixture (DMC), etc.silicone products are the products produced by polymerization reaction with add of inorganic fillers or modified additives. It mainly includes silicone rubber (high temperature vulcanized silicone rubber and room temperature vulcanized silicone rubber), silicone oil and its secondary processing products, silicone resin and silane coupling agent. And through the sulfur molding process, silicone rubber can be made into conductive keys, seal gasket, swimming cap and many other consuming products.

Silicone monomer

Although there are many varieties of silicone products, its starting raw materials for production are limited to a few organic silicon monomers. The top amount is dimethyldichlorosilane, followed by phenylchlorosilane. In addition, trimethylchlorosilane, ethyl and propyl chlorosilane, vinyl chlorosilane, etc., are also necessary raw materials in the production of silicone products.

The production of silicon monomer is not complicated. The main raw material for silicon monomer is silicon block, methanol and hydrogen chloride. At present,  methyl chlorochloride monomer is synthesized in boiling bed reactor. Silicon powder and chloromethane is reacted under catalyst at high temperature which makes methyl chlorochloride mixture. And through efficient fractionation, target fraction is obtained. Silicone monomers are made by hydrolysis, lysis and condensation to get different products. With silicon monomer as the raw materia and using different polymerization means and processes, different silicone products can be produced by adding various fillers and additives.The basic raw materials for production of silicone oil, silicone rubber, silicone resin and silane coupling agent are different kinds of organic silicon monomers. From these basic silicone monomer, thousands of organic silicon products can be produced. Organic silicon monomers mainly include: methyl chlorosilane (methyl-monomer), phenylchlorosilane (benzene-monomer), methylvinyl chlorosilane, vinyl trichlorosilane, ethyltrichlorosilane, propyl trichlorosilane, γ-chloropropyl trichlorosilane and fluorosilane monomer. Among them, methylchlorosilane accounts for the top amount,which is 90% of the total total monomer, followed by phenyl chlorosilane.

Organochlorosilane (methylchlorosilane, phenylchlorosilane, vinyl chlorosilane) is the basis of the whole  silicone industry, and methylchlorosilane is the pillar in the organic silicone industry. Most of the silicone polymers are polydimethyl siloxane made from dimethyldichlorosilane. After adding with other groups such as phenyl, vinyl, chlorophenyl, fluoroalkyl, etc., the product can meet special needs. The production process of methylchlorosilane is very long and has difficulty in production technician. This industry is  technology-intensive and capital-intensive. Therefore, the basic manufacturing site of the major foreign companies are in large-scale and under centralized construction.  While the downstream products manufacturing are distributed as per their use and market conditions.

The key of the development for any polymer material is the monomer technology development. The feature of the silicone industry is that the monomer production is concentrated and the further process of silicone products are in different places. Therefore, the production of monomer plays an important role in the silicone industry. And the level of monomer production is a direct reflection of  the development of the silicone industry. 

Silicone intermediates

Organic silicon monomers can be made into different silicone intermediates by hydrolysis (or lysis) and lysis. Silicone intermediates is the direct raw material to form  silicone rubber, silicone oil, and silicone resin. Silicone intermediates include hexamethylcyclotrisiloxane(D3),  octaethylcyclic tetrasiloxane (D4),  hexamethyyldisiloxane(MM), dimethyl cyclosiloxane mixture (DMC) and other linear or cyclic siloxide series.

 Silicone rubber

Silicone rubber is one of the important products among silicone polymer. Among all the rubber, silicone rubber can work under a wide temperature range, from -100℃~350℃. It is excellent in the high and low temperature resistance. According to its thionization mechanism, silicone rubber has three categories: organic peroxide-induced free radical crosslinking type (High temperature vulcanized silicone), condensation reaction type (Room temperature vulcanized silicone) and addition reaction type.High temperature vulcanized silicone rubber (HTV): thermal vulcanized silicone rubber is also called high temperature  vulcanized silicone rubber. All the direct chain siloxane with molecular weight between 500,000-800,000 is grouped as high temperature vulcanized rubber. Usually gum can be made with octaethylcyclotetrasilxane (D4) as the main raw material and get polymerized under the catalysis of acid or alkali. Then with oxides as crosslinking agent and combined with different additives (such as reinforcing filler, thermal stabilizer, structural control agent, etc.), it can be made into homogeneous rubber additives. Various rubber products can be vulcanized  by molding, extrusion or calendering, etc.,

Room temperature vulcanized silicone rubber (RTV) and addition reaction silicone rubber (LSR). Room temperature vulcanized silicone rubber  refers to the one which use  low molecular weight active polyorganosiloxane as the base material and can be formed  with the crosslinker and catalyst at room temperature.

Addition reaction silicone rubber refers to the silicone rubber which is made under the addition reaction with platinum compound as catalyst. It has no by-products during the reaction. Usually it is composed by vinyl terminated polydimethylsiloxane, silicone resin, low molecular weight polymethylhydrosiloxane, platinum catalyst and reaction inhibitor, etc., It is also known as liquid silicone rubber or LSR. Usually addition reactive silicone rubber is also vulcanized at room temperature (medium temperature), so it is also classified as room temperature sulfide silicone rubber.The above two of these are referred to as room temperature vulcanized silicone rubber.

 

Room temperature vulcanized silicone rubber has low molecular weight (from 10,000 to 80,000), and it is viscous liquid. As per different package form, it can be divided into single component RTV silicone rubber and two component RTV silicone rubber. Single component RTV silicone rubber mixes the raw rubber evenly with filler, crosslinker or catalyst in anhydrous conditions. And it will react with the moisture in the atmosphere after opening. While two component RTV silicone rubber usually puts the raw rubber and crosslinker agent or catalyst in seperate package.It will link together when mixed in a certain ratio. Its reaction is not related with moisture.

 

Silicone Oil or Silicone Fluid

silicone oil is a kind of polysiloxane liquid oil with different viscosity. It is not toxic, not corrosive, has no smell and not easy to burn. According to the chemical structure, silicone oil can be divided into methyl silicone oil, phenyl silicone oil,  ethyl silicone oil, methyl hydrogen silicone oil, methyl chlorophenyl silicone oil, methyl phenyl silicone oil, methyl ethoxy silicone oil, and methyl trifluoropropane, etc,. Among them, methyl silicone oil is the top item. By changing the polymerization degree of polysiloxane and the type of organic group, or making polysiloxane polymerized with other organic compounds, silicone oil with different properties can be made, such as waterproofing, anti adhesion, demolding or defoaming. Sililone oil can also be grouped into linear silicone oil and modified silicone oil.

Silicone oil has many special properties. Its features include low viscosity temperature coefficient, antioxidant resistance, good resistance to high and low temperature, high flash point, excellent insulation, low volatility, low surface tension, no corrosion to the metal, non-toxic, etc,. With these properties, silicone oil has excellent effects in different applications. Among all kinds of silicone oils, methyl silicone oil is the most widely applied and is the most important type followed by methylphenyl silicone oil. Different functional silicone oils and modified silicone oils are mainly used for special purposes.

silicone potting

Silicone resin

Silicone resin is a semi-inorganic polymer with silicon-oxygen-silicon as the main chain and with silicon atoms cross-linked with organic groups. It is emerged along with the silicone monomer produced by the silicone monomer. Its production is half year ahead of silicone oil and silicone rubber.

Silicone resin has outstanding weather resistance, which is better than any other organic resin. Even under strong ultraviolet irradiation, silicone resin still has good yellowing resistance. Silicone also has superior dielectric properties. The property can remain stable in a wide range of temperature, humidity and frequency. In additionn, it also has good oxidation resistance, irradiation resistance, smoke resistance, waterproof, mildew prevention and other characteristics.

 

Silane coupling agent

The general formula of silane coupling agent can be as: Y-R-SiX3. X and Y are two active groups with different reaction characteristics. X is easy to bind strongly with clay, glass, silica, metal, and metal oxides, while Y is easy to bind with resin and rubber in organic material. With both functional groups that can have good reaction with organic and inorganic material, silane coupling agent can bond organic and inorganic material together to reach satisfactory bonding. According to the number of hydrolyzed groups (X groups) connected to silicon atoms, silane coupling agent can be divided into two groups: trifunctional and difunctional types. In recent years, the production of silane coupling agent is controlled by several giant companies. In order to form a monopoly, every company has named their own product types, and for the same product, there are various names and types on the market. Union Carbide Corporation (UCC) is the world’s largest silane coupling agent manufacturer and has the largest number of product varieties.Silane coupling agent was first developed as a glass fiber treatment agent for glass fiber-reinforced plastics. The silane coupling agent has improved the adhesion between the glass fiber and the resin, thus the mechanical properties of the reinforced plastics are significantly improved. With the rapid development of composites, silane coupling agent also develops rapidly both in variety and output. In recent years, silane coupling agent has adopted some specific functional groups and this can improve the surface properties of materials, which get new properties such as antimildew, antistatic, anticoagulation and physiological inert. This has become new application for silane coupling agent. Along with the new development, silane coupling agent become an important branch of organic silicone.

 

Development history of silicone

All compounds containing Si-C bonds are generally called organic silicon compounds. Those connect organic groups like oxygen, sulfur and nitrogen to silicon atoms are also regarded as organic silicon compounds. Among them, the polysiloxane composed of silicone oxygen bond (-Si-0-Si-) accounts for the top amount in silicone compounds. It is the most studied and widely applied type in silicone compounds, which is more than 90% of the total.Silicone material has both properties of organic materials and inorganic materials.It has many good properties such as high and low temperature resistance, ozone resistance, electrical insulation, radiation resistance, flame retardant, water resistance, non-toxic and physiological inertia and other excellent characteristics. Silicone material is widely applied in electrical, electronics, construction, chemical, textile, medical and other industries.The main functions of silicone include: sealing, adhesion, encapsulation, lubrication, coating, lamination, surface-activity, releasing, anti-foaming, crosslinking, waterproofing, penetrating, inertion and filling, etc. With the continuous development of the quantity and varieties of silicone material, it has become one of the most important material in the new chemical material field. Many varieties of silicone are unable to be replaced  by other chemicals.

silicone factory

Different phases of silicone chemistry

Beginning period: In 1863, French scientists Fiddle and Kraft heated silicon tetrachloride and zinc diethyl to 160℃ in a sealing tube and synthesized the first silicone compound , which is etraethyl silane with Si-C bonds. Since then, many more tetraethylsilane derivatives have been synthesized. The fourty years from 1863 to 1903 was the founding period of silicone chemistry, which was also reffered to as the first phase

 

Growing period: From 1904 to 1937, there are many simple silicone compounds were synthesized. Meanwhile,some ring and linear polysiloxane (with-Si-0-Si-bonds as the backbone). From the theoretical aspect, the synthesis of asymmetric silicon atomic compounds has been started, which created circumstance for the study of silicone photoactive isoforms. These 30 years was refered to as the growing period of silicone chemistry, which is also called as the second phase.

Development period: Chemist Hyde from Corning as well as Patnode and Rojo from General Electronics realized that silicone polymer would have good future, and they have actively improved the  synthesis of silicone monomer. This helped the industrialization of  silicone. In particular, Rojo invented the direct synthesis method for methyl chlorosilane in 1941. This was a revolution in the production of silicone and was a good foundation for the large scale production of silicone compounds. In the 1940s, when some of the major countries realized industrialization, the equilibrium reaction methods of polyorganic siloxane was invented. And a complete system of industrial technologies was established. Different types of silicone oil, silicone rubber, silicone resin and silane coupling agent with excellent performance have emerged. The development of silicone industry was accelerated. The period from 1938 to1965 was called the third phase.

Boom period: Since 1966, further to consolidating, developing, improving and utilizing the existing achievements, silicone was also developing in the new field. Some compounds which was impossible to make can also be synthesized. One of the group with the fastest development is silicon —— metal bonding compounds. Especially chemical products formed by silicon and transition elements, and this has more practical value. And silicone chemistry has yielded fruitful results. So the period from 1966 has been called the fourth phase.

 

The development of science has promoted the development of production and construction. And the production in turn has new requirements for scientific research. In many industries, thermal resistance is needed. But normal organic polymers cannot meet the demands. Natural silicate is long known but its -Si-0-Si- bond is fragile. Therefore chemist introduced silicon atoms with an organic group, which can make them a linear structure or low-degree crosslinked polymer. Thus the silicone material can form flexible or elastic material, and the application would be further enlarged. The study on organopolysiloxane also started. Chemist Hyde from Corning Glass first combined silicone and polymer chemistry and gained experience in silicone polymerization.Under his guidance, silicone resin was produced for electronic insulated glass cloth. From 1938 and 1941, Hyde and his collaborators developed many more polyorganic siloxane products. Meanwhile, Dow Chemical also started study and production of polyorganic siloxane. In 1942,  dimethyl silicone oil and toluene silicone pilot plant was established.

In 1943, Dow combined with Corning glass and established the world-famous Dow-Corning Chemical. They built the synthetic polysiloxane factory in Midland. And soon they developed DC4 ignition sealing material, which was applied on  aerial aircraft in World War II. Then Dow Corning Chemical gradually became one of the world’s largest professional manufacturers of silicone products.

In the past 20 years, the application of silicone technology has achieved brilliant level. Room temperature vulcanized silicone rubber and silane coupling agent got comprehensive development. Silicone polymer for biological and medical use also emerged. Now, many more silicone compounds were invented for a wide application. Many impossible things can be realized now due to the development of silicone material

 

From an annual output of 10,000 tons in 1997 to about 850,000 tons per year in 2015, methylchlorosilane has a rapid development, which is top among all the monomer. In the future, with methylchlorosilane production capacity increasing, the organic silicon industry will have further development in technology, with both capacity and quality get onto a new level.

Organic Pigments

What are the basic information about organic pigments

As suggested by the name, coloring agents are the material that can provide people the color they need. Color agents have their own specific colors, which includes a variety of colors such as white, black, as well as gray.

Colorants are grouped into two categories: dyes and pigments. The main differences between dyes and pigments are:

Solubility: In the using process, dyes can be dissolved in the application(some dyes such as disperse dyes are partially dissolved), but pigments are not soluble or its solubility is very low. Solubility is a very important item that determines the performance of pigments such as migration and color penetrating. Sometimes, to improve the application properties of certain pigments, the solubility of pigments should be improved in the application.

In the using process, pigments have particle form and crystal shape. These play important roles in the color and application properties of organic pigments. Dyes dont have requirements on this aspect.

The color of pigment almost represents its using color in the substrate. With the dilute proportion, only the shade of pigments changes, but the basic color is not changing. This is to say that the color of the colored substrate is the color of pigment itself. While for dyes, the tone of the color will be changed when there is chemical reaction. They dyeing color is different with the color of dye.

Different Properties of Pigments    

Color shades of Organic Pigments

For a long time, visual judgement is the basic color evaluation way, which relies on the well-trained and professional color judge personnel. But it is difficult to judge whose eyes can be the standard judge. Along with the development of color evaluation judgement, a more  scientific evaluation system is established. The use of color tester can make the color description qualitatively and quantitatively.

The definition of color cannot be easily described orally. For example, what color can be called red? No matter how many modifiers are added, it is still not so accurate. Such as magenta, brick red, poldo red. But if we can make a color sample or a color card, the color is defined more obviously.

In the actual application, people like to choose a standard pigment as per their demand. And then they will test the new sample against their standard sample in certain testing system. A sample color will be made from standard sample and new sample and the shade difference will be compared. The common color system used is CIE*LAB system, and the XYZ three-stimulus value system that can be interconverted.

Organic Pigments color cards

Coloring strength

The concept of color strength has absolute color strength and relative color strength. Absolute color strength is based on pigment absorbance of lights, which is the maximum absorption wavelength or the overall absorption coefficient of the whole visible spectrum (the latter can be depended on the components of the different spectra).

Relative coloring strength is the relative value obtained from comparing the light absorption coefficient between the sample and the standard pigment. The ratio of the number of sample pigments matched to the number of standard pigments when reaching the same color depth.Accurate matches are not always found, because there are inherent differences in color light between the two, which cannot be eliminated by quantity alone, and whose color differences can be formulated through the CIE*LAB system.

The color force of the pigment will have different results according to its application conditions, that is, different color exhibition methods, as well as different measurement methods, and evaluation methods.

 

Opaque or transparency

It refers to the ability of pigment substrate to cover the color of the target layer. This is to define the covered area by paint colored with pigments, or it can refer to the the minimum thickness of the layer needed to cover the substrate.

To effectively cover the substrate, the coating must scatter. The amount of scattering is related with the coating thickness, the light absorption inside the coating, as well as the color difference of the substrate

Solvent resistance and various fastness

According to the definition of pigment,it should not be soluble in the application. but the absolute insolubility is not possible.There is certain solubility as per different application or different processing conditions. So if the solvent in in the carrier reach certain amount, recrystallization, color penetrating, or overflow will happen. It is very important to prevent the dissolution of pigment.The factors that can control the solubility of pigments include solvent, the particle size, the chemical structure of the pigment, as well as the processing temperature.

This is a testing method to judge pigment resistance to some solvent: put the pigment powder into filter paper, put it into a tube with solvent. The weight of the solvent and pigment should be determined. After a set at room temperature for the hours, the solvent resistance of pigment can be judged from the stained situation of solvent. This method may not fully represent the actual application, but the result is similar. If the pigment is vert dissolved , it could be problem for organic pigments to use in the application containing this kind of solvent. Problems such as color penetrating,  fastness or flow will occur.

 

Water resistance, soap washing resistance, alkali resistance, acid resistance:

For the above resistance, there are two aspects, one is about pigment’s chemical stability in these solvents and the other is the solubility in these solvents.

This resistance is mainly about pigments’s resistance situation in the processing and application stage. For example,in the water transfer process of pigment filter cake, it needs pigments to be good resistant to water. In the application of printing ink, it requires pigments to be resistant  to water or alkali water. In the application of exterior wall coating, it requires pigments to be resistant to the alkali in cement or lime resistant. During car washing, it requires organic pigments in automotive paint to be resistant to alkali water or detergent, etc.

Some pigments or lake pigments contain free alkaline or acid groups, will form salt in alkali or acid and this will cause color change, etc.

Threre are standard testing methods to test this properties. And the evaluation is according to level 1-5,grade 5 is best. A suitable testing method should be selected to test pigments. The test results are not same when pigment is directly exposed to acid and alkali or when pigments are made into coating and then exposed to acid or alkali.

Printing of package

Due to different packaging materials and the items packaged, there are different fastness requirements, such as oil resistance, wax resistance, cheese resistance, drug resistance, disinfectant resistance, steaming resistance, thermal sealing resistance (including the color change of coating and physical damage to the film, adhesion to the instrument) etc.

Organic Pigments

 

Textile fastness

Textile fastness refers to the colour maintaining ability of dyed filaments or dyed textile during processing or application.Such as water resistance during washing, peroxidation resistance, bleaching resistance of chlorine acid, friction resistance, sweat resistance (including enzyme),  ironing resistance, acid and alkali resistance, solvent resistance, dry washing resistance, and sodium hydrosulfite resistance, etc.

 

Migration resistance

Migration resistance efers to the occurrence of bleeding and frosting phenomenon.

Frosting means that the dissolved pigment will migrate to the surface again after it is erased. Bleeding means that the color will migrate to the similar material when get in touch.

The degree of migration is related to the particle distribution, chemical structure and content of the pigment.Migration is also related to all components of the material being colored, such as polymers, plasticizer, and stabilizers.

 

Effect on the pigment processing during application

Plate-out(ductility):During mixing or rolling, the pigment is deposited on the surface of the processing equipment or the system surface. Once the film is erased, it will not appear again.The reason is that the compatibility between lubricants, plasticizer, stabilizers and PVC is not good. And it is easy to migrate to the system surface, and bring out the pigment particles at the same time.  The method to avoid this is to reduce the pigment content or the processing temperature or adding hardener.)

Chalking(powder ization or pigment overflow): it mainly refers to the situation that the pigment carrier cannot completely wrap the pigment, and when it exceeds the critical volume concentration, the organic pigment will tun to the surface of the paint film. The reasons for chalking can be follows: high pigment content and less resin content; problem in the processing and pigments are not wrapped; large surface area; poor light and weather resistance of resin; poor light and weather resistance of pigments.

With the long time under UV and weathering time increasing, the pigment separated from the medium and the paint surface is damaged. The poor weather resistance of pigments or carrier materials promote pulverization.

 

Light resistance and weather resistance

light resistance: pigment’s ability to maintain the original color after long time sun exposure. The testing is based on the pigment dispersion system, not only the pigments. Most inorganic and all organic pigments will change color after long time light exposure.

The factors sensitive to light include the physical parameters (particle distribution, crystal type), the chemical structure of the pigment, and the properties of other components in the system.The xenon lamp is the standard test instrument for light resistance test.Pigment volume concentration,paint material, substrate, layer thickness, and other additive all have an influence on the test results.

Weather resistance: Light is not the only reason for the color change of the pigment. Other factors such as atmospheric water (or even the trace),industrial emissions, gas or climate changes also cause damage to the color of pigment. The test of weather resistance requires specific environments like temperature,light intensity, humidity, oxygen content, precipitation, air as well as the latitude and longitude and the proximity with the industrial zone. All these aspects will affect on the test result. Thus, industrial standards are formed in several countries.

The test will adopt accelerated aging instrument, which has similar condition with the outdoor environment. But for pigments with similar colors and different chemical structures, the exposure to xenon lamps or sunlight will vary due to the sensitivity of the pigments to the spectrum, especially in the UV region.

Thermal stability

The temperature resistance in the plastic industry and in the coloring of fiber raw pulp requires 260-320℃. This is a fatal natural defect for organic pigment as most organic pigments have a temperature resistance between 100 and 200℃. The thermal stability of the pigment is depended systematically. It not only depends on the chemical composition of the substrate, but also dispersion degree, processing conditions and pigment content.

In the coloring system, the reasons for thermal discoloration are: heat decomposition of pigments, chemical reaction of pigments with the substrate, the change of physical properties of the pigments, such as particle size change and the crystalline transition.

 

Fluidity

The viscosity of a system is determined by the overall component, including the actions between different components, dispersion conditions, and selection of components. The dispersion condition is most important such as wetting of the substrate, the opening of the aggregate, , dispersion degree and surface relationship. The influencing factors of pigment are as follows: concentration, particle shape, specific surface area, and surface structure.

Organic Pigments

Particle distribution and the property of substrate

Color strength: within certain range, The smaller is the pigment particles, the higher is the coloring strength of organic pigments. But after reaching the translucent point, the color strength will not further increase.(In the transparent system, there are pigments not following this rule).

Color shade: with the particle size increasing, the color will change as per some rules.The yellow color will shift to red; The orange color will shift to red shift, yellowish red  color will shift to blue, bluish red will shift to yellow, brown color will shift to red, purple color color will shift to blue, blue color will shift to red.

Light resistance and weather resistance: the larger the pigment particles, the better the light weather resistance.

Dispersion: pigment particles with narrow distribution is easier to disperse than wide distribution. Pigment with large particle size is easy to disperse. But dispersion is a complex process, disperison is also related with other factors.

Gloss: It is related with the dispersion of pigments and distribution of pigments. Bigger particle size has less gloss

Solvent resistance and migration resistance:  with the bigger particle size, solubility will decrease , and migration resistance will increase

Fluidity: the bigger the particle size, the better the fluidity and the less the viscosity.

 

Dispersion of pigments

The dispersion of pigment powder is related with many factors:

First are pigment related characteristics: chemical composition, particle distribution, crystal form, particle shape, surface structure, and the process of the pigment powder production, especially the drying and grinding process.

Second are physical and chemical properties of chemical components, which include molecular weight, polarity,  viscosity and compatibility of different components.

 

Popular Pigment Items for different application     

The manufacturer shall provide the pigment users certificates of analysis of pigments. But this is not enough for the application. End users should test organic pigments in their own paint, ink or palstic systems to confirm on if the organic pigments are suitable in their own product system.

Organic Pigments popular for paint include:Pigment Yellow 1, Pigment Yellow 3,  Pigment Yellow 17, Pigment Yellow 65, Pigment Yellow 74, Pigment Yellow 83, Pigment Red 2, Pigment Red 8, Pigment Red 22, Pigment Red 112, Pigment Red 122, Pigment Red 146, Pigment Red 170, Pigment orange 13,Pigment Orange 34,Pigment Orange 64, Pigment Violet 19, Pigment Violet 23

Organic pigments popular for Ink include:Pigment yellow 1, Pigment Yellow 12, Pigment Yellow 13, Pigment Yellow 14,  Pigment Yellow 83,  Pigment Red 81, Pigment Red 122, Pigment Red 254, Pigment Violet 3, Pigment Violet 27

Organic Pigment popular for Plastics: Pigment yellow 83, Pigment yellow 110, Pigment Yellow 180, Pigment Yellow 191, Pigment Red 53:1, Pigment Red 48:2, Pigment Red 122, Pigment Red 170, Pigment Red 254,  Pigment Orange 64, Pigment Violet 19

Silicone Adjuvants for fruits and vegetables

Why are silicone agriculture adjuvants important in agrochemical?

Pesticides play a significant role in the production of stable crops output and are  important in agricultural production. The application of pesticides is a common in agricultural production.With the improvement of people’s living standards and the development of society, food safety, production safety and environmental safety has get more and more attention from different parties. Like in China, government has carried out a plan of zero growth in pesticide use.

The zero increase in pesticide is mainly in two aspects. On one side, the using amount of pesticide has dropped, and one the other side the pesticide utilization rate has improved. Early, manual sprayers were mainly used in China for single farmers, and the amount of spary was large, but the prevention effect was not so good and the utilization rate was only around 25%, as most of the pesticides are lost to the air or soil.

While in recent years, the application of silicone adjuvant has taken changes in the pesticides formulation and application technology. With its outstanding effect in permeability, expansion, wetting, foaming, foam suppression, bubble stabilization and good compatibility performance, the utilization rate and prevention rate has been improved significantly. Thus, the using amount of pesticides can be reduced by 30%-50%. The add of silicone adjuvant in agriculture pesticides also save water, lessen pesticide residues, and reduce laber cost. And now agriculture adjuvant are widely applied in the agriculture production.

 

Today, from the characteristics and application of silicone adjuvants, it is hoped that the users can have a deep understanding of silicone adjuvants and to make reasonable use of it. This can help reduce agricultural production costs and improve the effectiveness.

adjuvants for fruits

Excellent performance of silicone adjuvants

The properties of agriculture silicone adjuvants mainly include the following three aspects: wetting, expansion and permeability.

1. Excellent wetting properties

Moisture resistance structure of composition is very normal in plant leaves, plant stems and insect epidermis. And on the surface of leaf, there is a negative charge, which makes pesticide liquid repellent and not easy to wet. Normally, when the pesticide spray has lower surface tension than that of leaf, the spray can moisten the leaf surface easily. On the contract, the pesticide spray will gather on the plant surface if its surface tension is higher, thus, the droplets of spray will concentrate on the leaf and roll down.

Silicone adjuvant has very low surface tension. After adding it into pesticide, it can make the pesticide spray moisten all the leaf surface and insect epidermis very easily. It can largely increase the contact surface of pesticide liquid to the target organisms, lessen the loss of pesticides and improve the utilization rate

 2. Superior expansion

The agriculture silicone adjuvant has superior expansion performance. After adding the silicone adjuvant into pesticide liquid, the area of expansion is around 10 times of the one without the silicone adjuvant. This superior expansion can make the pesticide liquid attached on the foliar and even make it onto the pests hidden in the fruit gap. Thus there can be direct contact of the spray liquid and pests may be killed.

3. Prime permeability

Stoma is one of the main approaches where the pesticide liquid spray permeate into the plant. Silicone adjuvants can help the pesticide liquid penetrate into the epidermis through the stoma easily. Also the absorption rate can be faster. Some studies show that silicone adjuvant has effective synergism on veramycin. It can take the pesticide liquid into the microscopic hiding place of pests. Then the pesticide liquid with silicone adjuvant will be absorbed by the leaf surface and get into the plant epidermis. It can also prolong the staying period of pesticide liquid, which is longer than pesticide liquid with mineral oil adjuvant.

Application of silicone adjuvants in pesticides

 

Silicone adjuvants can be used in pesticides as spray amendments, foliar absorptive aids or activators, etc. And it can be applied together with pesticides, herbicides, foliar fertilizer,or growth regulators.

1.Application in pesticides or herbicides

Silicone adjuvants are added into pesticides or herbicides. The herbicide solution is sprayed onto the leaves and stems of weeds, it will quickly penetrate into the cuticle and cytoplasmic membrane, and then transmitted to all the other parts of plant. After weeds get injury, the leaves and stems will deform and get dead. This can effectively improve the grass killing rate and prevention efficiency. This also contribute to the water saving and labor saving.

2.Application in foliar fertilizer

Foliar fertilizer is an efficient and fast way to supply nutrients to the plants. But foliar fertilization is not easy to penetrate into plants due to the impermeability of the plant epidermis to inorganic nutrient ions. So the infiltration through stoma is a good way for foliar fertilization. The adding of silicone adjuvants can improve the absorption of plants through stoma permeability and thus strengthen the fertilizer utilization rate.

3.Application in growth regulators

Silicone adjuvants can reduce the using amount and improve the using effect. For example, eryamycin is widely applied in citrus, but can easily antagonize with citrus. The use of agriculture silicone adjuvant can largely improve the function of  eryamycin and the using amount can be reduced to 10%. The adding of agriculture silicone adjuvant to enolazole can improve its efficacy and moisture, as well as reduce the using amount and cost of enolazole.

4. Application in insecticide and mite killer

The stoma of insects is extremely similar to the foliar ones.The silicone adjuvant can reduce the surface tension of the insecticide solution, help the spray solution penetrate into the insect trachea. This is very meaningful for the insecticide aid and synergist.For example, with the add of silicone adjuvant, the effect of 45g /hm2 20% buthiok budweiser emulsion is same as that of 75g/hm2. This can significantly lessen the field dose of buthiok budweiser emulsion by 20%.

How to use silicone adjuvant efficiently

1.Suitable dosage of silicone adjuvant

At the condition of normal temperature of 25℃ and moisture 60%, The add of 0.5% -0.1% silicone adjuvant into herbicide solution, the using amount of silicone adjuvant can be decreased by 30%, but with similar effects as conventional dosage of herbicides. Under drought conditions, The adding of 0.1% silicone adjuvant into herbicide solution can obtain stable herbicide effect.

In pesticides and fungicide spray, the adding amount of silicone adjuvants is around 0.025% to 0.5% -0.1%. The spray with silicone adjuvants can increase droplet retention time, improve droplet dispersion and absorption. Thus the efficacy can be improved.

The adding amount of silicone adjuvant into plant growth regulator is 0.025%-0 .05%. And the amount of fertilizer and trace elements are 0.015% -0.1% of the growth regulator spray. This can help improve efficacy and fertility.

2.Using Principles (Scope of Use) of silicone adjuvants

The silicone adjuvant have good work in the formulation. But its price is also higher than other adjuvants The global brand of silicone adjuvant sells at high price and the cost from China brand is like half of Momentive or Dow. So, during the use, users have to pay attention on the using principles to have good effects with less cost.

 

1.Apply to the crops that is difficult to wet and less use on the easy moistened crops

For crops easy to be wet, such as celery, rape, spinach, beans, tomato, pepper and other fruits and vegetables, there is no need to use silicone adjuvant. As the use of conventional adjuvants can meet the requirements of wetting crops.For wax crops that are not easy yo be wet, silicone adjuvants are encouraged to be used. Wax crops include rice, wheat, cabbage, finch wheat and weeds without leaves. The use of silicone adjuvants can improve the effect of the spray.

adjuvants for vegetables

2.Suitable for crops with hidden insect pests and diseases

For fruits like litchi, longan and grapes or vegetables like broccoli with hidden pests or germs, the adding to silicone adjuvants can make the pesticide spray better penetrating and spreading on the fruit gaps and leaves. So it can achieve the effects of eliminating pests or controlling germs.

 3.Suitable for crops in rainy areas

In the rainy areas, the use of silicone adjuvants can maximize the wetting and spreading of pesticide spray. Also, it can enhance surface permeability, improve its resistance to rain washing, and greatly reduce possibility of the loss of expensive pesticide as well as  decrease agricultural costs.

4.Suitable for UV sensitive pesticides or spray under strong summer light

For pesticides such as amimectin and methine amimectin benzoate, they are sensitive to ultraviolet light. The silicone adjuvants have super and rapid spreading capacity and can make almost instant stoma absorption. This can avoid photolysis, rapid evaporation and drying of the pesticide spray, and help in promoting the absorption of silicone adjuvants.

5.Pay attention to reasonable mixing

The use of some agriculture additives suppresses silicone effects; there are different additives used in the pesticide formulation. Some emulsifiers are antagonistic with silicone adjuvants and can not be used together. For example, acid compound emulsifiers such as 2201 # and 0206B# are suggested not to use together with silicone adjuvant as it is unfavourable to silicon-oxygen bond stability.

 

Notes for Use of Pesticide Silicone Adjuvants

The concentration and using amount should be strictly controlled. The appropriate concentration of silicone adjuvants with different kinds of pesticides is: herbicide 0.025% -0.15%, insecticide 0.025% -0.1%, fungicide 0.015% -0.05%,  plant growth regulator 0.025% -0.05%. The using amount with some powerful pesticides and herbicides should be reduced to prevent pesticide damage.

The spray cannot be used under high temperature conditions. If the temperature is over 30℃, it is better not to add silicone adjuvants when spraying pesticide. At this moment, the crop stoma is highly open, and the silicone adjuvant activity is very strong. And this strong permeability can cause harm to crops. If to spray the pesticide on the fruit trees, do not spray it directly on the fruit. To prevent rust points or rust spots, it is better to spray the pesticide after the fruit is bagged.

It is better spay the pesticide once after the silicone adjuvant is mixed together with it. silicone adjuvants are easily to be decomposed in both acid and alkali conditions and most pesticide preparations are obviously acidic. So, it is suggested to use pesticide on spot after mixed with silicone adjuvants.

Add certain volume of defoaming agent,.The silicone adjuvant is relatively active and easy to produce excessive foam. During the application, it is suggested to be added to the pesticide bucket of the sprayer at last to avoid excessive mixing. This can reduce the foaming amount. Also the adding of defoaming agent also helps.

 

Summary of silicone adjuvants in agriculture

There are different silicone adjuvant products available in the market. We should choose the silicone adjuvants that have trisiloxane active ingredient higher than 90% to ensure its excellent performance.

The silicone adjuvants have very low surface tension, super spreading ability and rapid absorption through stoma.Reasonable use of silicone adjuvants can reduce the using amount of pesticide, improve the utilization rate of pesticides, reduce production costs, and lessen the environmental pollution of pesticides.

However, everything has two aspects. With improper use of silicone adjuvants, it can cause drug harm to the crops. For example, the wax layer of some leaves is thin, if the using concentration is increased to get better penetrating effect can cause drug harm. In addition, the silicone surface tension is very low and has strong permeability. After entering into the water, it is toxic to the fish and easy to damage the gill function. So it better to prevent the flow of farm water into the breeding pond, thus the fish in the pond can be survived from the drug harm from the improper use.

Therefore, in the use of silicone adjuvants, we must bear in mind the using amount, the using note, and the using principles of silicone adjuvants. We should apply the silicone adjuvants as per its characteristics, and play its important role in the formulation. With the right instruction of silicone adjuvants, it is believed that they can have good performance in the controling of pests, lower farmer’s cost as well as protect the environment. The different supplying choices from China silicone adjuvant producers also make the cost lower but with the similar application effects.

 

crop

What is a pesticide silicone surfactant or silicone adjuvant?

 

Agirculture additive has a strong potential market increase in recent years. By 2023, The growth of the global agricultural additives market will come from USD 3.13 billion in 2018 to USD 4.04 billion, and the compound annual growth rate is 5.24%. The market increase is due to the the popularity of global integrated pest management,the improvement of pesticide quality, the development of green additives solutions, and the limit requirements on crop residues. Surfactant accounts the biggest market share in agricultural additives and among the surfactant, silicone agriculture adjuvant is the top increasing group. As per some datas, the silicone agriculture adjuvant will have highest increasing till year 2023. The development of silicone agriculture adjuvant has changed the situation of agriculture additive field.  In the past few years, there are more than 50 different items got registration in USA and Canada. The demand and good feedback on silicone agriculture adjuvants also stimulated the global market demand on it. The crop protection company is also considering the use of silicone raw material in the developing of new products and biological acaricides, etc.

 

The North America market is the biggest market for agriculture additives, with the participation of top global brands like Dupont, Huntsman, Helena, and Momentive. In the Asia pacific market, with more investors in China, India and Thailand, the agriculture additive and silicone agriculture adjuvant will have high compound annual increase in Asia pacific market.

 

Why agriculture adjuvant is need in the crop protection?

In the crop growing process, pesticides and herbicides are necessary. But there is certain side effects in using them. One is environmental pollution, and the other is the cost. In the using of pesticides in large scale, it will lead to environmental pollution with pesticides residue. This wil affect the eco enviroment as well as health of people. If the dosage is too low, the insecticidal effect will not be good. If the dosage is too high, it will easily cause phytotoxicity and pollution to the environment.

 

So, in the use of pesticides, agriculture adjuvant is often used. They are inactive, but can increase the utilization rate of pesticides. And silicone adjuvant is widely applied in pesticides among all the agriculture additives for better effect. What would be the feature of pesticides mixed with silicone adjuvant?The excellent wetting ability of silicone adjuvant enable the liquid pesticide to spread fast on the surface of leave, strengthen the adhesion of the liquid pesticide, improve the utilization rate of the pesticide, lessen the loss of the liquid pesticide, and stop the pesticide from infiltrating the earth and leading to water pollution.

 

The application of Silicone Adjuvant in pesticides

 

In the 20th century, silicone surfactants are started to use as pesticide, and in the 1980s, the commercial promotion in agriculture industry began. In 1985, Monsanto New Zealand was the first in launching silicone surface agent L-77 ( Silwet M) . Extensive indoor chemical tests and field trials are made.

 

There are more than 5000 types and more than 10000 brands of silicone products in the market. The total global sales amount of silicone products is around 12 billion euro and the sales amount of Dow Corning has accounted for one third of the total amount. The second company is Momentive, which is also the top in the agriculture field. Silicone has many different properties such as good electrical property, good weather resistance, excellent air permeability, safety in touch with people, and low surface tension(which is related with agriculture industry).

 

Silicone surfactant has different types, and the most applied types are Polyether silicone oil, emulsified methyl silicone oil and amino silicone oil. The main functions are used as defoamer(for paint, ink and agriculture), wetting agent(for agriculture), leveling agent(for paint), hand feel agent(for textile and leather), and dispersing agent(for the dispersion of powder in water or oil). Besides, one of the biggest market is in cosmetics area. The global market share is around 3 billion Euro.

 

The structure and property of silicone surfactant

Silicone surfactants are grouped into four categories: cationic, anionic, nonionic and zwitterionic.  The hydrophilic part of silicone surfactant is various ionic groups or polyoxyalkylene ethers and the hydrophobic part of the silicone surfactant is polysiloxane. If classified according to their structure, organosilicon surfactants can have hydrophilic group on both ends or on side chain as well as block copolymer structure.The structure of non-ionic silicone surfactants is grouped into type A and type B, type A side chain is composed of polyoxyalkylene ether, and type B end group is polyoxyalkylene ether;

structure

 

The main function of silicone surfactant applied in agriculture area is for wetting and defoaming. The most popular function at present is wetting. The adding of silicone adjuvant in agriculture is very effective with low dosage. Generally speaking, 0.1% can have a good wetting ability. And 0.02% can achieve good effect. Organic fluorine has lower surface tension, but its wetting ability may not be as good as silicone product. There are various types of silicone surfactants, but those applied in agriculture area is limited. Its application in agriculture industry is not so long, but the effects are very obvious. Like around 10 years ago, Momentive has cooperated with agriculture department, which have promoted the development and application of silicone adjuvant in agriculture area.

Comparing with non-silicone surfactant, the obvious feature of silicone surfactants is low surface tension, high temperature resistance and good microbial resistance. The surface tension of non silicone surfactant is over 30mn/m, and the surface tension of silicone surfactant is 20mn/m. with the lower surface tension, the contact angle of water solution and solid surface will also be lower.

The surface tension of surfactant solution

Types of surfactant Mass fraction in water/% Surface tension(25℃)/mN.m-1
Alkyl polyoxyethylene ether(TX-10) 0.1 31.6
Alkyl polyoxyethylene ether(EO=4) 0.1 34.1
Sodium dodecyl sulfate 0.1 41.7
Non-ionic silicone surfactant 0.1 20.0
Ionic silicone surfactant 0.1 21.3

 

With the lower surface tension of silicone surfactant, the contact angle of hydrophobic surface is smaller. So, the wetting speed on the hydrophobic surface(like PU film) is faster and the wetting diameter is bigger.

The wetting speed and wetting diameter of surface surfactant on PU film

Surfactant types Wetting Speed Wetting Diameter/mm
Without surfactant 1 1.0
OP-10 2.6 3.0
Silicone surfactant 1 6.4 23
Silicone surfactant 2 7.8 32
Silicone surfactant3 12.6 40

 

The function of silicone adjuvant in agriculture pesticides

Pesticides are the necessary chemicals used in the growing process of crops, vegetables and fruits. They are applied to kill various germs, pests, and weeds. The reason is that most pesticides (including herbicides) are soluble in oil but not soluble in water; therefore before using them, pesticides need to be emulsified into an oil-in-water emulsion. Later water also need to be added to dilute them into very low concentration. The diluted emulsion will be sprayed onto the leaves, stalks and stems of crops, fruits, vegetables as well as weeds to inhibit or kill the growth of various germs, pests, and weeds. Generally, the surface tension of the aqueous solution with other surfactant is above 30 mN/m; but the surface tension of the aqueous solution of silicone surfactant is mostly around 20 mN/m. The surface tension of aqueous solution is related with its wetting ability and wetting speed on the solid surface. The lower the surface tension, the faster the wetting on the solid surface and the larger of the wetting area. On the surface of leaves and stems, there is a thin hydrophobic wax film. When the leaves and stems are sprayed with pesticide emulsion with normal surfactants, the spreading area is small and the wetting speed is slow. Because of the capillary effect, the pesticides cannot penetrate into many small pores. And those pests can still survive where it is not wetted by pesticides. The situation is similar on herbcides as the weeds cannot be removed if herbicides cannot penetrate into the pores of the weeds. If the herbicide formulation can be added with a small amount of organic silicone adjuvant, the using amount of of herbicide can be lessened to one third. As with the very low surface tension of silicone surfactants, the pesticide emulsion can have rapid wetting and penetrating into every small part of the leaves, stalks and stems of plants. And the effectiveness  of the pesticides can be strengthened and the effect of time can be prolonged.

The effect of herbicides added with silicone adjuvant on weeds control rate(%)

Without use of herbcides 0
Herbcides+normal surfactant 40
Herbcides +silicone adjuvant 1 80
Herbcides +silicone adjuvant 2 76
Herbcides +silicone adjuvant 3 81

From the data, it can be seen that the control rate on weeds has been improved by 100% comparing with silicone adjuvant and non silicone adjuvant.

 

Adding silicone surfactants into Avermectin pesticides, the initial lethality of red spider mites can be 100% and some can still reach 65% after 21 days

The effect of silicone surfactant on lethality on red spider mites

Types Start 7days 14 days 21days
+Water 10 5 0 0
Pesticides(0.12g/L))+non silicone surfactant 100 85 55 45
Pesticides+ silicone surfactant 100 80 95 65

 

The use of silicone adjuvant in pesticides and herbcides is very significant with its low surface tension. With the lower surface tension, the contact angle with the hydrophobic solid surface is smaller, and the wetting speed is faster, and the wetting diameter is large. Thus, the amount of herbicides can be decreased by more than one-third but with the same control rate of weeds. Also the amount of pesticides can be reduced, as well as get better killing effect on pests and longer function time.

 

Silicone adjuvant can greatly improve the spreading force and adhesion of the liquid pesticide on the surface of plants or pests, increase the utilization rate of pesticides, speed up the pests’ absorption of pesticides, and get a better insecticidal effect, thereby reducing the amount of pesticide spray.Silicone adjuvants can promote the penetration of systemic pesticide liquid through stomata, and strengthen the resistance to rain erosion. Further spray is not needed after rain.Silicone adjuvant can also reduce the using amount of pesticide and water, lower down pesticide pollution, and decrease pesticide residues. It can be used together with fungicides, insecticides, and plant growth regulators.

 

Top Global company in Silicone Agriculture Adjuvant

Momentive is the top 2nd company in silicone field, and its shanghai based agriculture department has set up agrochemical laboratories for indoor biological activity determination and formulation development. Its agriculture silicon adjuvant products are applied in agricultural fields in large scale such as pesticides,plant growth regulators, foliar fertilizers, etc., and the effects are very outstanding. Momentive’s Silwet series of agricultural synergists have good market reputation around the world. The Silwet series can be used in field sprays, as well as be added into pesticide formulations. Its performance in improving pesticide effect, lessening water consumption, reducing labor intensity, and saving average costs is very significant. Silwet 408, Silwet L77 and Silwet 618 are the popular types in the agriculture markets.

 

What should be the using amount of silicone adjuvant in agriculture products?

Silicone adjuvants are very efficient and eco friendly non-ionic surfactants. Its application in agriculture industry has changed the pesticide formulations and application techniques greatly. Because of its good wettability, permeability, expandability , good compatibility, foaming, foam suppression and foam stabilization, it can improve the utilization and application effect on a significant scale, as well as decrease the using amount of pesticides by 30%-50 %.

 

Although silicone adjuvant has significant effect in the use with pesticides, attention should be paid in its use to ensure a better function. While use silicone adjuvants together with pesticides, the concentration and the dosage should be strictly controlled. The recommended concentration of silicone adjuvants mixed with different kinds of pesticides is: herbicide 0.025%-0.15%, fungicide 0.015%-0.05%, insecticide 0.025%-0.1%, and plant growth regulator 0.025%-0.05%. The using amount together with powerful insecticides or herbicides should be decreased to prevent phytotoxicity.

 

With the development of silicone adjuvant products from different companies, farmers will have more choices to choose the top quality silicone adjuvant to improve the out yield of their crop products with less cost.

agriculture pesticide

What is Agriculture Adjuvants for Plants?

Agriculture adjuvants is one member in the pesticide products. It is used together with pesticides in certain condition and improves the effects of pesticides. When mixed with pesticides raw material in the production process or mixed with pesticides, these substances can improve the physical and chemical properties, improve the pesticide effects and become easy to use. They are grouped as pesticides additives or agriculture adjuvants. In general, pesticide adjuvants have no biological activity, but the selection of agriculture adjuvants will impact much on the efficiency of pesticide formulations.

The smooth surfaces of many fungi, plants and insects make the penetration of pesticide spray solution not easy. To solve this, adjuvants have been used together with pesticide solution. Adjuvants can help improve the function of pesticide if used in a suitable way. Adjuvants can be any additive that is added into a spray tank which strengthens pesticide performance. For example, adjuvants can be spread stickers, surfactants,buttering agents, crop oils, compatibility agents and anti-foaming materials. Surfactants are adjuvants that stimulate the dispersing , emulsifying, dispersing, wetting, or spreading of the pesticide solution on the plants. Most pesticides need to be used together with adjuvant. If adjuvants are not added into insecticides  herbicides,or fungicides, the pest control can only be reached less than 50%. Adjuvants can help imrpove the effciency of pesticds and the right use of adjuvant on plants is very critical.

 

The types of agriculture adjuvant

 

There are various types of agriculture adjuvants. According to statistics, there are over 3000 types of agriculture adjuvants all over the world and 200 types of them are used often. The agriculture adjuvant can be grouped by using method, function, surface activity, structure, and molecular size etc.

Different agriculture adjuvant

(Diagram 1) Different Agriculture Adjuvant

 

1.Sorted by Function

The agriculture adjuvants added in the production process of pestcides are called formulation additives. As formulation additives, agriculture adjuvants are added into pesticides formulation in the production process, and this can meet the requirement of physical and chemical stability of pesticide formulation as well as meet the requirement of commercial performance. As per the function and effect in the formulation, the adjuvants can be grouped into:diluent, solvent, dispersant, wetting agent,  filler and/or carrier,  emulsifier, spreading agent, penetrant, controlled release agent, Defoamer, warning pigment, dustproof agent , stabilizer, foaming agent,  thickener and thixotropic agent, etc.

When the agriculture adjuvants are mixed with the finished pesticides products, they are called pray additives or tank-mix additives: spray additives refers to additives that are added in to pesticides spray directly and this can help improving the utilization rate of pesticides, the performance of pesticides spray, as well as the control effect of plant diseases.  There are agriculture adjuvants with properties such as absorption promotion, sedimentation promotion, , anti-drift, anti-evaporation, rain wash resistance, as well as synergists, water quality regulators, , and phytotoxicity reducing agents. The most regular additives are mineral oil based and vegetable oil based synergists or silicon adjuvants, surfactants, , liquid fertilizers and polymer additives that help increasing the rain wash resistance, wetting and spreading of pesticides.

 

2.Sorted by whether it has surface activity

Since most pesticides cannot be soluble in water, different types of surfactants are added in to pesticides to meet the water dispersibility and process performance requirement. Thus, the agriculture adjuvants are divided into two categories: surfactants (natural or synthetic) and non-surfactants.

Surfactants can be divided into ionic surfactants and nonionic surfactants according to the structure of hydrophilic groups. Ionic surfactant molecules can ionize in water and get positively charged, negatively charged or both positively and negatively charged ions. Positively charged ions are called cationic surfactants. And its main types are quaternary ammonium salt type surfactants and amine salt type surfactants. Negatively charged ions are called anionic surfactants. Its main types are sulfonates, higher fatty acid salts and phosphate, etc.;

Ions with both negative and positive charges are called amphoteric surfactants. Betaine type Amino acid type, and  imidazoline type, amine oxide surfactants are the main types. Non-ionic surfactant molecules can not ionize in water and are neutral in electrical. The main types are polyethylene glycol type and polyol type.

Non-surfactant agriculture adjuvants mainly refer to the inert substances that are added into pesticide formulation, such as fillers, solvents, and other substances which can  improve the physical and chemical properties or stability of the pesticide formulation. Non surfacant agriculture adjuvants includes fillers, carriers, fillers or adsorbents like kaolin, white carbon black,  inorganic salts, clay,urea, sawdust, and starch,etc.; solvents and co-solvents such as ethers, alcohols, vegetable oils or hydrocarbons; PH regulators such as sodium carbonate, sodium tripolyphosphate, and citric acid; Warning pigments such as rose essence, brilliant blue and acid red.

 

3.Sorted by molecular weight

Surfactants can be grouped into two types: polymer type and ordinary type as per molecular weight. Ordinary surfactants has a molecular weight from several hundred to several thousand. Polymer type sufactants has a molecular weight from several thousands to several tens of thousands. Polymer type surfactants can be grouped into three categories: synthetic, semi-synthetic and natural, semi-synthetic and synthetic as per their sources. Synthetic polymers have types like polyvinylpyrrolidone, acrylic polymers, polyvinyl ether, polyvinyl alcohol (PVA), and polyacrylamide, etc; Semi-synthetic surfactants include carboxymethyl cellulose (CMC), hydroxyethyl cellulose (HEC) and cationic starch; Natural polymer surfactants are mainly pectin,  starch, protein, and alginic acid (sodium) etc;

How does agriculture adjuvants work for plants?

By understanding how water works, we can know better how agriculture adjuvants works.The molecule of water is bipolar, and it has a positive charge and a negative charge. The negative charge and positive charge will attract each other like magnet.

Comparing with the internal water molecules, the surface molecular of water is more attracted together. This cohesion leads to surface tension and make substance be resistant to tensile force. And surface tension will prevent things from getting wet. But the agriculture adjuvants or surfactants can break surface tension.The surface tension are reduced by agriculture adjuvants from two aspects.The first is to increase the unbalancing of surface molecules, and the second is to decrease the attraction among surface molecules, thus the tightness of surface is reduced.

surface tension broken

(Diagram 2)Surface tension is broken by surfactant molecule

The agriculture adjuvants molecule help reduce the surface tension and make pesticides more spread on the plant surface and reach the target. When different substances get in contact with water molecules, different results will happen. If the two substance are different in charges, the two forces will hold together with each other. If the two substances are same in charges, the two forces will repel. If the two substances don’t have charge, nothing will happen. Due to the surface tension, water will drop on most surfaces of plants. But this surface tension can be adjusted by the agriculture adjuvants of pesticides.

When the pesticide solution with agriculture adjuvant has lower surface tension, the pesticide will have better spread on the leaves and the effect of pesticides will be improved. Meanwhile, it can decrease the using amount of pesticides, reduce the affect of pesticides on environment, and bring benefits to the agriculture industry. But due to the pesticides are very special, so it should be careful in choosing the agriculture adjuvants.  The synergistic effect of agriculture adjuvants on pesticides is a show of its effectiveness on target organisms. Agriculture can help the distribution and cohesion of pesticides on the surface of organisms be better. It can also strengthen the absorption of pesticides by organisms of plants, and thereby improve the biological activity of pesticides

Different agriculture adjuvants have their own function. Some adjuvants help in diluting the original pesticide; some help in preventing the beads from gathering and becoming larger; some can improve the wetting, adhesion and penetrating of the particles. In summary, the main function of agriculture adjuvants is to improve the chemical and physical properties of pesticides and is to maximize its effects with safe application. Agriculture adjuvants are developed along with the pesticides development. More types and series of agriculture adjuvants are innovated to meet the requirements of different pesticides products. Professional formulation and processing technique is also developed to meet the farmers’ requirements.

Which brands of agriculture adjuvants are popular in the market for plants?

Among different agriculture adjuvants, wetting adjuvants are one of the popular types that are used together with pesticides. Agriculture wetting agent can make insoluble pesticides diluted in water and make it have wetting ability. It can help decrease the surface tension of water and make the substrate wet. And the pesticide with wetting adjuvants can be well spread on the surface of insects, crops, and weeds. Thus the removal effect can be improved and less pesticides can be used.

wetting agent with different effects

(Diagram 3)Wetting agent with different effects

Following are some popular wetting adjuvants types and their brand names

1.Pull open powder BX

This wetting agent is an old wellknow brand. It is one type of the sodium salt of butyl naphthalene sulfonate. Its water solubility is good and has very less bubbles. But the problem is that the original powder of BX is very difficult to get and the sold products are not original mostly. Also the prie varies much due to different content of BX. The Nekal BX Dry sold by BASF is one of the open powder series,which has good effects as well as higher cost.

2.K12, K14 (Sodium Lauryl Sulfate)

K12,K14 is another common wetting adjuvant. It has very good effect and white color.  But when it is exposed to acid, it is easy to decompose. And there will be bubbles occur which are not easy to eliminate. And its cost is also low among the wetting adjuvants.

3.Akzo Nobel’s Morwet EFW

Akzo Nobel’s Morwet EFW is one type of wetting adjuvant with excellent performance. It is a mixture of anionic wetting agent and alkyl naphthalene sulfonate. The typical property is that it has excellent water solubility as well as very low bubbles. In WDG, Morwet EFW is good ombination with dispersant D-425 for dispersing and wetting.

4.Rhodia’s Igebal BC/10

Rhodia’s wettingadjuvant is liquid type wetting agent and it works very well in pesticide formulation.

5.Hanmok’s W-2001

Beijing Hanmok’s wetting adjuvant is fine wax particles. Its solubility in water is normal but its cost is also not very high. In WDG, is good combination with dispersant D-1001 and D-1002 for dispersing and wetting.

6.Momentive Silwet 408

Momentive Silwet 408 is used in large scale together with pesticide in spray. The wetting ability is very excellent and reasonable cost. Similar sillicone adjuvant from China also perform well and with better price.

 

Benefits of agriculture adjuvants for plants

Some types of pesticides must be used together with supporting additives to ensure their effects. For example, dicamba and glyphosate must be used along with designated supporting agriculture adjuvant.

The application of appropriate agriculture adjuvants can improve the effects greatly. For example, if the insecticide malathion spray is added with the pesticide spreading agent Triton CST (0.1% concentration), and the effect of killing black beetles in 72 hours can reach 83-93% (but in single use of malathion, it can only reach 6%.

Supporting adjuvants need to meet the special requirements of certain application technologies, which can make it be effective in the application. For example, ultra-low volume spray technology has requirement on diluents or formulation carriers or phytotoxicity reducing agents; foaming spray method has special requirement for foam stabilizers or foaming agents; electrostatic spray technology has requirements not only on ultra-low capacity, but also needs special antistatic agent system.

To keep safety, different agriculture adjuvants are needed in some pesticides application. For example, anti-drift agent can prevent the neighboring sensitive crops, animals and humans from poisoning of pesticides drifting.The adding of warning colors can also help warn people to keep away from poisoning or accidental ingestion. The herbicide is very active, but its selectivity is not sufficient. To protect the crop from phytotoxicity, herbicide needs to be used together with the safe additives. The wetting agent is helping improving the effects of pesticides, with a better spreading and penetration of pesticides on the surface of different plants and crops. Different kinds of agriculture also help the agriculture industry get a better enviroement to nearby plants, animals and humans, especially the green agriculture adjuvants developped along with the technology improvement.