What are the adhesive compositions?
The synthetic adhesive consists of a main agent and an auxiliary agent, and the main agent is also called a main material, a base material or a binder; the auxiliary agent has a curing agent, a diluent, a plasticizer, a filler, a coupling agent, an initiator, a thickener, The antioxidant, the polymerization inhibitor, the stabilizer, the complexing agent, the emulsifier, and the like may further include a flame retardant, a foaming agent, an antifoaming agent, a coloring agent, and an antifungal agent according to requirements and uses.
The main agent is the main component of the adhesive, which dominates the adhesive bonding properties and is also an important indicator for distinguishing the adhesive category. The main agent is generally composed of one or two or even three kinds of high polymers, and it is required to have good adhesion and wettability. The substances that can be used as adhesives are:
1. Natural polymers, such as starch, cellulose, tannin, gum arabic and sodium alginate and other plant-based adhesives, as well as animal glues such as bone glue, fish gelatin, blood protein glue, casein and shellac.
2. Synthetic resin, divided into two major categories of thermosetting resin and thermoplastic resin. Thermosetting properties such as epoxy, phenolic, unsaturated polyester, polyurethane, silicone, polyimide, bismaleimide, allyl resin, furan resin, amino resin, alkyd resin, etc.; thermoplastic resin such as polyethylene , polypropylene, polyvinyl chloride, polystyrene, acrylic resin, nylon, polycarbonate, polyoxymethylene, thermoplastic polyester, polyphenylene ether, fluororesin, polyphenylene sulfide, polysulfone, polyketone, polyphenyl ester , liquid crystal polymer, etc., as well as modified resins or polymer alloys thereof. It is the most used type of adhesive.
3. Rubber and elastomer. The rubber mainly includes neoprene rubber, butyl nitrile ethylene propylene rubber, fluorine rubber, polyisobutylene, polysulfide rubber, natural rubber, chlorosulfonated polyethylene rubber, etc.; the elastomer is mainly thermoplastic elastomer and polyurethane elastomer.
4. In addition, there are inorganic binders such as silicates, phosphates, and phosphoric acid-copper oxide.
In order to meet specific physicochemical properties, various auxiliary components are added as auxiliary agents, for example, in order to form the bulk material into a mesh or body structure, increase the cohesive strength of the adhesive layer and add a curing agent (they are bonded to the main body). Reacting and producing cross-linking action; adding a curing accelerator or catalyst to accelerate curing and lowering the reaction temperature; adding an anti-aging agent for improving weather resistance, heat aging, arc aging, ozone aging, etc.; Adding fillers for properties and cost reduction; adding a toughening agent to reduce the rigidity of the rubber layer and increasing toughness; adding a diluent for improving the processability, reducing the viscosity, and prolonging the service life. include:
6. Coupling agent
7. Other additives: initiator, accelerator, tackifier, polymerization inhibitor, stabilizer, anti-aging agent, complexing agent, emulsifier.
The bonding technology has also matured and become one of the three major connection technologies for bonding, welding and mechanical connection.