1. Rubber type pressure sensitive adhesive.
It is a kind of pressure sensitive adhesive widely used at present, including natural rubber, synthetic rubber and recycled rubber. The pressure-sensitive adhesive with natural rubber as adhesive has good compatibility, pressure-sensitivity and creep resistance, but its aging resistance is poor and its hardness changes greatly; The pressure sensitive adhesive with synthetic rubber as adhesive has good heat resistance and durability, but the adhesive strength is poor; If the recycled rubber is adhesive, only the recycled rubber of natural rubber can be used. For the pressure-sensitive adhesive with natural rubber as the adhesive, natural rubber and synthetic rubber can be used together, partially vulcanized and cross-linked, grafted or modified with appropriate reinforcing filler. These methods can improve the aging resistance of the adhesive layer and prolong the service life of the adhesive.
2. Acrylate type pressure sensitive adhesive.
The adhesive of acrylate pressure-sensitive adhesive is a copolymer of acrylate and other ethylene monomers. The copolymer monomers are divided into main monomers, secondary monomers and functional monomers. The main monomer is butyl acrylate, etc., which is used to provide toughness and adhesion; The secondary monomers include methyl methacrylate and styrene, which are hard monomers and can provide rigidity and cohesive strength; Functional monomers are monomers containing other functional groups, such as hydroxyethyl methacrylate, which can play a cross-linking role in the polymerization process and further improve the adhesion, cohesion and thermal creep. This scientific monomer combination can make the copolymer itself have the basic properties of pressure-sensitive adhesive, so the acrylate pressure-sensitive adhesive is almost one-component.
Acrylate pressure-sensitive adhesive has excellent weather resistance, heat resistance, good oil resistance, transparent adhesive layer and no phase separation and migration. Because various polar groups can be introduced through copolymerization, which increases the secondary force between molecules, so it has relatively large adhesive strength and cohesive strength.
3. Silicone pressure sensitive adhesive.
Silicone pressure-sensitive adhesive is composed of silicone rubber and silicone resin. Silicone rubber is the basic component of pressure-sensitive adhesive, and silicone resin is the tackifier. The performance of pressure sensitive adhesive changes with the change of their ratio. Generally, the end of silicone resin has active end groups. The commonly used ones are methyl silicone resin, methyl phenyl silicone resin, and phenyl vinyl silicone resin. They all have good thermal stability. Organosilicon pressure sensitive adhesive has outstanding adhesive performance advantages.
The pressure sensitive adhesive tape is generally made into a ribbon reel, which has three forms: single-sided adhesive coating, double-sided adhesive coating and adhesive sheet. Single-sided gluing is to apply pressure-sensitive adhesive after applying primer on the front side of the base material, and then apply the back treatment agent on the back side, and then the drum can be used; The adhesive tape coated on both sides and the film coated on one side do not need the back treatment agent, but need a layer of isolation paper on one adhesive surface; Primer, also known as primer and primer, can enhance the adhesion of pressure-sensitive adhesive to the substrate and prevent degumming by applying the primer between the pressure-sensitive adhesive and the substrate. The back treatment agent is a layer of material that is applied on the back of the single-sided adhesive tape substrate and can act as interlayer isolation when the adhesive tape is rolled into a circle. For double-sided adhesive tapes, labels, adhesive tapes, adhesive sheets, etc., a layer of isolation paper shall be covered on the surface of the pressure-sensitive adhesive.
The pressure-sensitive property of pressure-sensitive adhesive is the performance of its adhesion property, which consists of four elements: fast adhesion, adhesion, cohesion and adhesion.
1. Fast adhesion, also referred to as initial adhesion, is a kind of interfacial peeling force that is displayed when the adhesive tape and the adhesive are separated immediately after contacting with the adhesive at the lightest pressure and the fastest speed, and also shows the wetting ability of the adhesive and pressure sensitive adhesive to the adhesive.
2. Adhesion force refers to the peeling force reflected between the adhesive tape and the surface of the object after proper adhesion, and its size determines the adhesion performance of the adhesive tape.
3. Cohesive force is the cohesive strength of the adhesive layer, which is related to intermolecular force, intermolecular bond, molecular size and intermolecular arrangement.
4. The adhesive base force is the adhesive force between the pressure sensitive adhesive and the base material. Generally speaking, the relationship between the above four forces is fast adhesion<adhesion<cohesion<adhesion
