The early formulation of the three-proof glue is polyurethane. Now the main formula is acrylate. One is silicon-containing material. If the three-proof glue is made of this material, it can't be used on PCB with an unsealed relay, because the three-proof glue will volatilize into Sio2 and adhere to the contacts of the relay, which will make the relay lose its conductivity.
01
Acrylic acid: (strong corrosiveness, moderate toxicity. Its aqueous solution or high concentration of vapor can irritate the skin and mucosa. )
Acrylic acid is an organic compound with chemical formula C3H4O2. It is an important raw material for organic synthesis and synthetic resin monomer. It is also an ethylene monomer with very fast polymerization speed. It is the simplest unsaturated carboxylic acid, consisting of a vinyl group and a carboxyl group. Pure acrylic acid is a colorless clarifying liquid with a characteristic irritating odor. It is soluble with water, alcohol, ether and chloroform and is prepared from propylene obtained from refineries. Most of them are used to produce methyl acrylate, ethyl ester, butyl ester, hydroxyethyl ester and other acrylates. Acrylic acid and acrylate can be homopolymer and copolymerized, and their polymers are used in synthetic materials, synthetic fibers, super absorbent resins, building materials, coatings and other industrial sectors.
Chemical properties:
1. Flammable. Its vapor and air can form explosive mixture, which can cause combustion and explosion when exposed to open fire and high heat. It reacts strongly with oxidants. In case of high heat, polymerization reaction can occur, which releases a large amount of heat and causes vessel rupture and explosion accidents. It is easy to self-agglomerate in heat, light, water, peroxide and iron, and cause explosion.
2. Combined reactions with double bonds and carboxyl functional groups, addition reactions, functional group reactions and transesterification reactions, long preparation of polycyclic and heterocyclic compounds, easy reduction to propionic acid by hydrogen, and decomposition to formic acid and acetic acid by alkali.
3. Strong acidity. Corrosive. Chemical properties are active. It is easy to polymerize into transparent white powder. Propionic acid is formed during reduction. Addition with hydrochloric acid produces 2-chloropropionic acid. Acrylic acid can react with carboxylic acid and alcohols to obtain corresponding esters. When acrylic acid and its esters are mixed with other monomers, homopolymer or copolymer will be formed.  Monomers commonly copolymerized with acrylic acid include amides, acrylonitriles, vinyl groups, styrene and butadiene. These polymers can be used to produce various plastics, coatings, adhesives, elastomers, floor polishes and coatings.
4. This product has strong corrosiveness and moderate toxicity. Its aqueous solution or high concentration of vapor can irritate the skin and mucosa. LD50 was 590 mg/kg orally in rats. Be careful not to contact with acrylic acid solution or steam. Wear work clothes and caps, protective glasses and rubber gloves when operating. Production equipment should be sealed. Work and storage places should have good ventilation conditions.


02
Polyurethane: (Smell big)
Polyurethane is a class of polymers with NHCOO - repetitive structural units in the main chain, abbreviated as PU, which is synthesized by the polymerization of isocyanate (monomer) and hydroxyl compounds. Because of its strong polar carbamate group, insoluble in non-polar groups, it has good oil resistance, toughness, wear resistance, aging resistance and adhesion. Materials suitable for a wide temperature range (-50-150 C) can be prepared from different raw materials, including elastomers, thermoplastic resins and thermosetting resins. It is not resistant to hydrolysis or alkaline medium at high temperature. Including rigid polyurethane plastics, soft polyurethane plastics, polyurethane elastomers and other forms, and divided into two categories: thermoplasticity and thermosetting. The raw materials are usually in resin state. In addition to being a single material, polyurethane can also be mixed with other materials to form composite materials.
The main application fields of polyurethane coatings are: vehicle coating, ship, wood, building coating, anti-corrosion coating, aircraft, plastics, rubber, leather surface coating and so on.
Waterborne polyurethane coating, with water as the main medium, has the characteristics of low VOC content, low or no environmental pollution, easy construction and so on. It is one of the main substitutes for solvent-based coatings. It has been widely used in many fields, such as: (1) wood paint and wood floor paint; (2) paper coating; (3) building coating; (4) leather coating; (5) fabric coating, and so on.




03
Silicone:
Organosilicon is a kind of silicone compound, which contains Si-C bond and at least one organic group is directly connected with silicon atom. It is customary to regard those compounds which connect organic group with silicon atom through oxygen, sulfur and nitrogen as organosilicon compounds. Among them, polysiloxane, which is composed of silicon-oxygen bond (-Si-O-Si-) as the framework, is the most abundant, the most deeply studied and widely used type of organosilicon compounds, accounting for more than 90% of the total dosage.
Silicone
Silicone resin is a highly cross-linked network structure of polyorganosiloxane, usually with methyl trichlorosilane, dimethyl dichlorosilane, phenyl trichlorosilane, diphenyl dichlorosilane or methyl phenyl dichlorosilane of various mixtures, in the presence of organic solvents such as toluene, water decomposition at lower temperatures, to obtain acid hydrolysates. The initial product of hydrolysis is a mixture of cyclic, linear and cross-linked polymers, usually containing considerable hydroxyl groups. The hydrolysate is washed to remove acid, the neutral primary condensate is oxidized in air or further condensated in the presence of catalyst, and finally a highly cross-linked three-dimensional network structure is formed.
Silicone resin is a thermosetting plastic. One of its most outstanding properties is its excellent thermal oxidation stability. The weight loss of silicone resin is only 2-8% after heating at 250 C for 24 hours. Another outstanding performance of silicone resin is excellent electrical insulation.