What are the crosslinkers? How to choose a crosslinker?

1, external cross-linking agent

The so-called external crosslinking agent is added before use, and then a crosslinking reaction occurs at room temperature, under heating or irradiation. The added crosslinking agent is further divided into the following categories:

(1) Polyisocyanate (JQ-1, JQ-1E, JQ-2E, JQ-3E, JQ-4, JQ-5, JQ-6, PAPI, emulsifiable MDI, tetraisocyanate).

(2) Polyamines (propylenediamine, MOCA).

(3) Polyols (polyethylene glycol, polypropylene glycol, trimethylolpropane).

(4) Glycidyl ether (polypropylene glycol glycidyl ether).

(5) Inorganic substances (zinc oxide, aluminum chloride, aluminum sulfate, sulfur, boric acid, borax, chromium nitrate).

(6) Organic matter (styrene, a-methylstyrene, acrylonitrile, acrylic acid, methacrylic acid, glyoxal, aziridine).

(7) Silicone (ethyl orthosilicate, methyl orthosilicate, trimethoxysilane).

(8) Benzenesulfonic acid (p-toluenesulfonic acid, p-toluenesulfonyl chloride).

(9) Acrylates (1,4-butylene glycol diacrylate, ethylene glycol dimethacrylate, TAC, butyl acrylate, HEA, HPA, HEMA, HPMA, MMA).

(10) Organic peroxide (diisopropylbenzene peroxide, bis(2,4-dichlorobenzoyl peroxide).

(11) Metal organic compounds (aluminum isopropoxide, zinc acetate, titanium acetylacetonate).

(12) Aziridine

(13) Multifunctional polycarbodiimide crosslinking agent.

(14) Closed crosslinker

(15) Isocyanate crosslinking agent

2, internal crosslinking agent

The term "intermediate cross-linking agent" means to enter a macromolecular structural chain as a monomer during polymerization, or as a component to be added to an adhesive, which can be stably stored, and can only be produced when heated to a certain temperature or radiation condition. Joint reaction. Commonly used internal crosslinking agents are ethylenic monomers such as acrylic acid, hydroxyethyl acrylate, hydroxypropyl acrylate, methacrylic acid, hydroxyethyl methacrylate, hydroxypropyl methacrylate, divinylbenzene, N- Methylol acrylamide, diacetone acrylamide.

Tips for selecting crosslinkers:

For different adhesives, the appropriate cross-linking agent should be selected. For cross-linking agents, the following requirements are required:

(1) The reactive group of the crosslinking agent can react with the components in the adhesive to form a crosslinked structure.

(2) The crosslinking efficiency is high, and a stable crosslinked structure can be obtained by adding a small amount.

(3) The cross-linking speed is suitable, and too fast and too slow is unfavorable.

(4) A mixture of several cross-linking agents can be used to obtain the best overall effect.

(5) The crosslinking agent is stable during the process and storage period, and no harmful reaction or cohesion occurs. Non-toxic, non-irritating, and non-polluting.