Introduction to Modified Silicone Oil-Part 1

Cited from: https://pixabay.com/photos/hard-drive-hdd-technology-digital-870691/

Cover Page cited from: https://pixabay.com/photos/crystal-healing-stone-gemstone-1685590/

Each time when we mentioned silicone oil, there is a high chance that refers to the dimethyl or methyl silicone oil. However, this time we are going to introduce several types of modified silicone oil while dimethyl or methyl silicone oil is just the linear silicone oil.

The modified silicone oil which is sold on the market could be divided to two categories:

The first is the carbon functional group silicone oil. It means the silicone oil contains functional groups (include Si-R-X key) which are linked by carbon to some silicon atoms directly.

The second type is the inactive modified silicone oil which means some silicon atoms are linked to inactive groups or polymer chains.

Modified silicon oil contains some excellent physical & chemical properties of dimethyl silicone oil and is widely used in developing high-efficiency and multifunctional new material applications.

Polyether Modified Silicone Oil

Polyether modified silicone oil (or polyether silicone oil) is linked by polyether links and siloxane links via chemical keys. The polyether link chains give the silicone oil hydrolysis and the polydimethylsiloxane chains give it a low surface tension. Therefore, other organic products cannot compare the properties with it while pure siloxane is also weaker than polyether silicone oil.

Polyether silicone oil has been widely used as emulsion liquids, raw material to personal production products, anti-foaming liquids and many other industries. Now it is becoming the largest produced modified silicone oil.

The links between polyether chains and siloxane chains are in two ways: by Si-O-C key, or by Si-C key. The former one is unstable and is easy to be hydrolyzed; the latter one is more stable to water.

Now there are five main types of polyether silicone oil are sold in the market: SiOC type main chain form, SiOC type side chain form, SiC type side chain form, SiC type two-end form, SiC type single-end form. Among them, the SiC types take more percentages in today’s market.

Methyl hydrogen silicone oil and polyester are the main raw materials to manufacture polyether modified silicone oil.

The usages of polyether silicone oil determine the specific chemical structure and the components of polyether silicone oil especially the polyether silicone oil which is used for defoaming liquid which has strongly selectivity and specialty.

Aminoalkyl Silicone Oil

Aminoalkyl modified silicone oil could be considered as the dimethyl silicone oil whose partly methyl are altered by amonoalkyl. Aminoalkyl silicone oil not only contain some properties of dimethyl silicone oil like hydrophobicity and demoulding,

but also the existence of aminoalkyl could award the silicone oil some properties like reactivity, softness and many other excellent characteristics. Therefore, it is widely used in the textile industry as fabric softener, polisher and resin modifier. It is also now the biggest consumed carbon functional group silicone oil.

Amonoalkyl silicone oil’s amonoalkyl mainly contains NH2, NHCH2CH2NH2, NHC2H4NHC2H4NH2 and OC6H4NH2. Different amonoalkyl silicone oil provides different functions and properties.

Hydroxyalkyl Silicone Oil

Hydroxyl modified silicone oil’s C-OH key could be reacted with groups like OH, Cl, COOH and NCO of organic compounds to allow the polysiloxane and organic polymers to be connected by Si-C chemical key. This reaction could improve the physical and chemical properties of organic polymers. There are a variety of hydroxylalkyl which are linked to silicon atoms, but the ones who are mainly existing in different goods are: -(CH2)nOH (n = 1 ~ 5), -(CH2)3OC2H4OH, -(CH2)3OCH2CHMeOH, -(CH2)3OCH(OH)CH2OH, -(CH2)3OCH(CH2OH)2 and –CH2CHMeC6H4OH.

There are mainly three ways to produce hydroxyalkyl modified silicone oil: Hydro silylation addition method, condensation and metallic compound method. The first method is considered as the most important production technique.

During the reaction of hydro silylation addition method, besides the reaction between Si-H key and unsaturated key, Si-H key could also be able to react with other active compounds who contain hydrogen (like water and alcohol) which will make the whole process to be more complex. Therefore, it is a must to ensure the raw material used is dry.

Mercaptoalkyl Silicone Oil

It is due to the active nature of mercaptoalkyl silicone oil’s –RSH, this silicone oil is widely used in printers and other materials that use modified organic resins. The mercaptoalkyl that appears in silicone oil goods contains –CH2SH, -CH6SH, -CH2CHMeCH2SH, -CH2CHMeOC2H4SH, -COCH2CH2SH and –C3H6NHOCH2CH2SH. It is because the reaction of mercaptoalkyl is complex, then people do not produce them directly from active silicone oil. The manufacturing process usually begins with producing siloxane which contains mercaptoalkyl then produces silicone oil which has mercaptoalkyl in its main chain or side chain with the agents like (Me2SiO)4 or (Me3Si)2O. Thus, to get siloxnae which has mercaptoalkyl is the key for manufacturing mercaptoalkyl silicone oil.

It is just like other modified silicone oil, there are also many ways to produce mercaptoalkyl silicone oil, and however, the best solution is haloalkyl silane conversion method.

Thiourea method is the widest method to produce mercaptoalkyl siloxane, but it needs the raw materials to be very dry.

Sodium sulfide method is a simple way, but it still contains many steps. The method not only costs a long time for the reaction, but also has a lower collection rate of the final matured product. Therefore, in the past people preferred to use thiourea method. However, it is since the corresponding technologies have some advanced breaches, to take DMF as agent has reduced the negative effects brought by its shortages.

Thioacetic acid method has the pros of simple processing and higher collection rate and this makes it become a better manufacturing solution.

Summary

This article just introduces around half of the main categories of today’s mainly selling modified silicone oil. The introduced types are widely applied in different markets or industries due to their different chemical structures or physical & chemical properties they have.

Modified silicone oil also has many differences from the common linear silicone oil which includes dimethyl silicone oil.