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 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 agriculture 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.