Pressure-sensitive adhesive tapes are generally made into strip rolls, which are available in single-sided, double-sided and adhesive sheets.


  1. Single-sided coating is to apply pressure-sensitive adhesive on the front side of the substrate, and then apply the pressure-sensitive adhesive on the reverse side.


  2. Double-sided adhesive tape and single-sided adhesive film do not require a backside treatment agent, but require a layer of release paper on a rubber surface. The substrate of the adhesive tape is the basic material for supporting the pressure sensitive adhesive. As the substrate of the pressure sensitive adhesive, it must have good mechanical strength, uniform thickness, not easy to be deformed, and is well wetted with the pressure sensitive adhesive. Commonly used substrates are cotton, glass cloth, synthetic fiber and other fabrics, polyethylene, polyester, polyvinyl chloride and other plastic films.


  3. Primer, also known as the bottom treatment agent, primer. Applying the primer to the pressure sensitive adhesive and the substrate enhances the adhesion of the pressure sensitive adhesive to the substrate and prevents degumming. There are two types of primers: mixed type and graft type. The mixed primer is a mixture formed by blending a resin having affinity for a substrate with a resin having affinity for a pressure sensitive adhesive. The graft copolymerization primer is obtained by graft copolymerizing a monomer having a affinity for a pressure sensitive adhesive as a main chain and a resin having affinity for a substrate. Some of the pressure-sensitive adhesives have a strong adhesion to the substrate without applying a primer.


The back treatment agent is a layer coated on the back side of the single-sided adhesive tape substrate to isolate the layers when the adhesive tape is wound into a circle. This treatment also enhances the physico-mechanical properties of the substrate. When the back treatment agent is selected, it is required to have good interlayer isolation ability. When the tape is peeled off, the back side cannot be provided with the pressure sensitive adhesive of the lower layer, and good transparency and non-migration property are also required. Commonly used back treatment agents are polyacrylates, polyvinyl chlorides, cellulose derivatives, and organosilicon compounds. Different substrates or pressure sensitive adhesives, different treatment agents are used, and several treatment agents can also be used in combination. For double-sided adhesive tapes, labels, adhesive tapes, adhesive sheets, etc., a layer of release paper should be covered on the surface of the pressure-sensitive adhesive. Commonly used release papers include semi-rigid polyvinyl chloride film, polypropylene film and kraft paper coated with a back treatment agent.




5 adhesive properties of pressure sensitive adhesive




The pressure sensitivity of pressure-sensitive adhesive is the performance of its adhesive properties. Its adhesive properties are composed of four factors: fast tack (A), adhesion (B), cohesion (C) and adhesion (D). consist of,


  1. Fast adhesive force (A) refers to an interfacial peeling force that is exhibited when the adhesive tape is separated from the adherend at the lightest pressure and at the fastest speed. It can be understood as the initial viscosity, the viscosity and the ability of the pressure-sensitive adhesive to infiltrate the adherend, etc., which is difficult to define strictly.


  2. Adhesion (B) refers to the peeling force exhibited between the adhesive tape and the surface of the adherend after proper bonding, and the size determines the adhesive property of the adhesive tape.


  3. Cohesion (C) is the cohesive strength of the rubber layer, which is related to the inter-molecular force, the intermolecular bond, the molecular size and the arrangement of the molecules.


  4. Adhesive force (D) is the adhesion between the pressure sensitive adhesive and the substrate or the adhesion between the pressure sensitive adhesive and the primer and the primer and the substrate. Because the relationship between these four forces should satisfy A<B<C<D, the properties and dosage of each component and its influence on the adhesion characteristics should be strictly observed when designing the pressure-sensitive adhesive formulation.