optical brightener white t-shirt

Optical Brighteners (OB): Everything You Need to Know

Optical brighteners are fascinating chemicals because they absorb light in the ultraviolet and violet spectra (340 nm–370 nm), which lie in the electromagnetic spectrum. After absorbing, they emit this light into a different region (blue, 420–470 nm) while displaying the phenomenon of fluorescence.

The bluish haze added by optical brightening agents removes the yellowish feel from substances and gives them a fresh look.

Alternatively, optical brighteners are known as:

Optical Brightening Agents (OBAs)

Fluorescent Brightening Agents (FBAs)

Fluorescent Whitening Agents (FWAs)

Their primary function or effect is that they give a whitish and bright appearance to several products to which they are frequently added. A detailed discussion about the applications and uses of optical brighteners is provided later in this blog post.

optical brightener white t-shirt


Before going into further details of applications, let’s dive into the properties and types of optical brighteners:

Types of OB:

Optical brighteners (OB) can be classified into different categories depending on the number of sulfonic groups in the structure.

The following are different categories of optical brighteners:

Disulfonated optical brighteners.

Tetrasulfonated optical Brighteners

Hexasulfonated optical brighteners.

Now let’s discuss each of them a bit more in detail:

Di-sulfonated Optical brighteners:

As is visible from the suffix “Di,” this type of OB consists of two sulfonic groups. They show resistance to water and are very unlikely to show solubility in other solvents. They have a degree of affinity for cellulose; therefore, they are used in wet-end addition.

Tetra-sulfonated Optical Brighteners:

Tetrasulfonated OBs are those that contain four sulphonic groups. They are comparatively less hydrophobic, show better solubility, and have a medium range of affinity. Because of their medium affinity, they can be used in both dry and wet end additions. The paper industry is where they have found themselves most useful.

Hexa-sulfonated Optical brighteners:

Hexa stands for six, so it’s pretty obvious that they contain six sulfonic groups. Because a greater number of sulfonic groups corresponds to greater solubility, hexasulfonated optical brighteners have high solubility. For the same reason, they are only used in dry-end addition techniques. Their primary use is due to the extreme brightness they bring to different substances.

Properties of Optical Brighteners:

Optical brighteners bring a lot of beneficial properties to the table; let’s get deep into them.

Brightness and Whiteness:

When the white textile fabric is produced in the factories, observers are called to check the whiteness of the fabric, and white textile that is freshly made often gives off a yellowish haze, which often dampens the look and aesthetics of the fabric. Adding a bluer tint to the fabric makes it look whiter. If you grew up in the 1990s, you probably remember seeing blue laundry detergents used in the washing process to give it a brighter tint.

As explained at the start, optical brighteners emit blue light, and when this property is added to the textile, they give it a brighter look and get rid of the yellowish feel. Having a greater affinity for cellulose, they become excellent for use in cellulose-containing fabrics.

The brightness of OB can be boosted by the addition of “polyols,” primarily due to an increase in the emission of blue light. On the other hand, excess brightness should also be avoided because it may add a greenish haze, which is not desirable.


This is a property of any colour-producing material that indicates how resistant it is to fading when exposed to light. OBs introduce a significant amount of lightfastness when added to the cellulose-containing fabric. On the other hand, when added to fabrics like Xylon, their light fastness increases more than that of cellulose, and in the case of polyester, there is an even higher rating of light fastness being added by OBs.

Washing fastness:

It is the property of the colour dyed on fabric; it is the measure of how resistant a dyed colour is to the effects of the washing process. The washing fastness added by OBs is in the medium range, and it might degrade with time, particularly in the case of cellulose textiles. In the case of other textile materials, the washing fastness of OBs may last for the life of the textile material.

Optical Brighteners’ Applications:

Let’s briefly discuss the uses of OBs:

Laundry detergents with optical brighteners:

Laundry detergents have some quantity of optical brighteners added in to brighten the washed clothes, and this has vastly replaced the blue dye that was added to white fabrics while washing previously.

OB in the Paper Industry:

Optical brighteners are often used in the paper industry for increased brightness, which often gives a better background for writing. On the other side of the coin, banknotes do not use such fluorescent agents, and therefore this characteristic can be used to check for fake banknotes.

white paper brightened by optical brightener

Optical Brighteners in the Cosmetic Industry:

The same feature of adding brightness can make eye powders and face powders favourable products in which optical brighteners can be used. They are also used to treat blonde hair for conditioning purposes and add luminance to it by using optical brighteners.

optical brightener added in face powder

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Most Frequently Asked Questions about Dimethyl Silicone.

Silicone has been the most popular chemical in recent times, whether it is in the form of silicone implants or silicone gels. With COVID’s exponential growth in e-commerce marketplaces, silicone products were always trending on various social media platforms. The upward trajectory of the popularity of silicone products has been around for almost two decades. Most people have only known silicone as a thick, viscous gel-like material or as the primary hard material used in various chips around the world. Although silicone chips have played a massive role in the tech revolution, there are many other silently incorporated roles for silicone in many of the fast-moving consumer goods we use daily. Most of these lesser-known facts about the use of silicone come from the fact that silicone is also available in liquid form, which is often referred to as silicone oil or silicone fluid. Silicone fluid comes in a variety of polymerized forms, and probably the most famous one is dimethyl silicone.

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Whenever a question comes to mind, people often go find the answer on the internet. We have noticed that not a lot of information is present on a single page where you can find all the answers. Here we’ll try to answer most of the questions being asked frequently.

What is dimethyl silicone?

Dimethyl silicone, also known as silicone oil, is a tasteless, odorless, and colorless chemical that appears to the naked eye to be water, even though it is not soluble in water. It is soluble in many organic compounds such as benzene, toluene, ether, chloroform, ether, and many others. Various steps are involved in the production of dimethyl silicone, such as:

  • Hydrolysis
  • Neutralization
  • Cracking
  • Fractionation

Dimethyl silicone has found its application in a lot of industries, such as the cosmetics industry, paint industry, food industry, car polishing industry, and many more. Dimethyl silicone is much more incorporated into our lives through multiple products than ever before.

Can you eat dimethyl silicone?

Do you want to eat dimethyl silicone? I bet you can’t because it is a liquid in the first place and can be drunk, but it has no taste, which makes it highly unlikeable to be drunk. But don’t assume that it can’t be used in the food industry. Dimethyl silicone is a key ingredient in cooking sprays, where it provides non-stick properties and also acts as a good anti-foaming agent. It is also used as an additive. The only care needed with dimethyl silicone while using it in food processing is avoiding its direct contact with fire as it is flammable, so always use it with care and in smaller quantities.

a man eating

Where can I buy dimethyl silicone?

Dimethyl silicone is not rare to find. It can be bought online at several e-commerce marketplaces, but that quantity might only be for small businesses or individual users. For large-scale purchases, contacting manufacturers around the world might be the best way to get your hands on some high-quality, low-priced dimethyl silicone. The majority of silicone fluid manufacturers are located in China. Often, these manufacturers tend to have websites where you can find contact details such as a phone number, email, or LinkedIn page. The other way to go about looking for dimethyl silicone oil is by using websites like Alibaba or Made in China, where you can browse through a lot of vendors selling silicone oil. However, one of the most vexing aspects of weeding out these vendors is that sometimes middlemen enter the picture, resulting in a higher price. Hengyi Technology provides a solution to all these problems with the association of several dimethyl silicone oil manufacturers. You just need to tell the company the quantity and type of silicone fluid required, and Hengyi will provide you with the best quote for your desired amount.


Is dimethyl silicone toxic?

It is a non-toxic substance, and in fact, it is very useful in the food industry. It is marked as a safe food additive, and its use in cooking sprays is just increasing day by day. Okay, that’s about toxicity for humans. Is it toxic for plants? Although it is used as an adjuvant with many herbicides and pesticides, when used alone on plants, it is not a toxic substance and doesn’t cause retardation in the growth of plants or even pests. However, drinking silicone oil should be avoided, as it can cause low-grade irritation. It should also not come into contact with the naked eye.


toxic mask

Can dimethyl silicone cause cancer?

Dimethyl silicone being used in the food industry signals its safety for human consumption in low amounts. Although rumors of its safety kept circulating as “health hazardous” or “cancerous,” there is no scientific proof to support this gossip. To be safe, the World Health Organization recommends no more than 43 g of cooking spray containing dimethyl silicone per 40 kg of body weight per day.


cancer surviving kid

Is silicone oil good for hair?

Silicone is used in several hair products, and it creates a water-repellent layer around your hair that keeps it hydrated over time. It is not dangerous, but long-term use may cause hair to dry out and lose strength. Silicone buildups in the hair are hard to remove, and they generally go away in 7 to 8 washes. There are many specific silicone-free shampoos available on the market, but silicone is still used by a lot of shampoo and haircare product manufacturers.



Can silicone oil stay in the eye forever?

Before going into the discussion about whether silicone oil can stay in the eye forever or not, it is important to know why silicone oil is injected into the eye. Silicone oil is injected into the eye to replace vitreous humor (a gel-like substance), which is generally lost when there is retinal detachment of the eye. The inclusion of silicone oil in the eye prevents the aqueous humor from reaching the retina. After the vitreous humor heals itself, silicone oil is often removed from the eye, or else it will lead to an increase in intraocular pressure. Silicone oil typically lasts 3–4 months before being surgically removed after complete recovery.



Why is silicone used instead of oil in acrylic pouring?

Acrylic pouring is a type of abstract art in which acrylic paint is poured into each other. The most prominent feature of acrylic pouring is the creation of cells. There are many ways to achieve it, and one way is through the addition of silicone oil to acrylic paints. Only a few drops of silicone oil are needed to create cells when pouring acrylic.


acrylic pouring dimethyl silicone cells


Silicone Adjuvants in Agriculture as Herbicides. What else?

Silicone adjuvants are used frequently in agriculture for increasing the effects of agricultural herbicides and pesticides. Before going deep into the discussion, let’s understand first what adjuvants are. They can be simply explained as support chemicals that can be added to herbicides, pesticides, and insecticides to increase their effectiveness and also add several beneficial characteristics.



Agricultural adjuvants are primarily used as an herbicide but their use as insecticides, fungicides, acaricides, and plant growth regulators are also being established.

It’s time to dive further into details of how Silicone Agricultural Adjuvant can be used in different modes:

Silicone Adjuvants for Herbicides:

When these adjuvants are added to the herbicides, they either improve or sometimes lower the potential of the herbicides depending upon the nature of the adjuvant it is being added in. Enhancing the effect of herbicides by adding adjuvants seems pretty straightforward forward but why we would want the adjuvant to decrease the effects of herbicides? Sometimes, the herbicide might be needed to eradicate the growing herbs in crops, and using the herbicide at its full capacity might prove harmful to the crop itself and that is where adjuvants come into play to save the crop while killing the herbs at the same time.


Roles of different types of Silicone Adjuvants along with Herbicides:

Activator Adjuvants:

As the name suggests, these types of silicone adjuvants increase the activity of herbicides by enhancing the following characteristics:

  • Increased absorption into the plant surface.
  • Decreased photodegradation of herbicides leads to increased time of activity of herbicides or increased life of herbicidal action.
  • Changes the physical properties of herbicides.

Plants have a thick outer surface known as a cuticle which must be penetrated by herbicides to be effective. The cuticle is made up of wax which is water-repellent in nature and cutin and pectin which are somewhat less repellent to water. Wax is the major factor that limits the absorption of herbicides as the hydrocarbons are the primary component in the wax. The amount of wax and type of wax changes across different species which makes it a bit tricky in choosing the right adjuvant which can help herbicide cross the cuticle easily. 


Surfactants can be anionic, cationic, nonionic, and organosilicon. They are used after herbicides. The main function of surfactants is to decrease the surface tension between spray droplets of herbicide and plant surface.


Nonionic surfactants can be used in combination with a lot of pesticides because it carries no electrical charge. While anionic surfactants carry a negatively charged functional group. Anionic surfactants are more specific and are only compatible with some specific herbicides. Only one cationic surfactant (ethoxylated fatty amines) is commonly used with herbicides. Organosilicon is a relatively newly introduced group of surfactants, and they are replacing the old non-ionic surfactants because of lower surface tension, better rain fastness, and other improved properties than those of non-ionic surfactants.

Silicone Adjuvants for Insecticides and Acaricides:

Silicone surfactants are not very reactive, but their capability to penetrate insects is mainly because the outer layer of insects is somewhat similar to that of plants. Silicone surfactant penetrates the insect’s stroma due to decreased surface tension.


Silicone Adjuvants for Fungicides:

Silicone adjuvants used in fungicides are not very much known and there is limited knowledge available. Fungicides are not required to be absorbed into the leaf surface for effectiveness. Instead, they tend to perform better when they stay on the surface of the plant to keep them protected from fungus. 

Contrary to the protective fungus, the systemic fungus is required to be absorbed to perform its function. Silicone adjuvants may prove helpful in the cause of system fungicides. 

Silicone Adjuvants for Plant Growth Regulators:

The use of silicone-based adjuvants such as siloxane polymers has proven to show an increased effect on plant growth regulators and this action is due to increased uptake of plant growth regulators. An example of a silicone adjuvant in plant growth regulators is the use of silicone adjuvant with manganese salt and phosphate which is applied to wheat crops, and it tends to give more outcomes than any other surfactant used.


agricultural silicone adjuvants

To sum up the discussion, silicone adjuvants play a vital role in increasing the outcome of crops and reducing the potential damage or harm which can be inflicted by herbs, pests, fungi, and other factors.

Hengyi Technology provides a variety of agricultural silicone adjuvants to be used by manufacturers around the world.