Pressure sensitive adhesives are mainly solvent-based or latex-based adhesives of acrylic and rubber series. Due to the need of high-speed operation, reasonable coating and elimination of solvent pollution, the warm melt pressure-sensitive adhesive has been developed, which integrates the characteristics of hot melt adhesive and pressure-sensitive adhesive. It is solvent-free, pollution-free and convenient to use. It is applied in the molten state, and after cooling and curing, it can play a bonding role by applying slight finger pressure.

It is widely used in diapers, women's products, double-sided adhesive tapes, labels, packaging, medical and health care, book binding, surface protective film, wood processing, wallpaper and shoemaking. The consumption of HMPSA for packaging is the largest, accounting for almost half of the total. The main component of hot-melt pressure-sensitive adhesive is mainly styrene thermoplastic elastomer. The advantage of hot-melt pressure-sensitive adhesive is solvent-free, thus no air pollution, and high productivity. But the disadvantage is the lack of heat resistance and cohesion. New thermoplastic elastomers such as SEBS, SEPS and epoxidized SBS are used to prepare higher performance warm melt pressure sensitive adhesives.

The new acrylate block copolymer has heat resistance, oxidation stability, UV stability, good adhesion to HDPE, stainless steel, glass, polystyrene, acrylic plate, polycarbonate, nylon, polypropylene and other materials, and can be used to make medical tapes, transparent films, labels, etc. The hot-melt pressure-sensitive adhesive that can be dispersed in water is made of acrylic polymer and water-soluble polymer. Acrylic polymer is dispersed into 100 μ The following non-adhesive particles are easy to separate and suitable for recycling of old paper. Acrylic acid copolymer with low Tg was obtained by copolymerization of acrylate monomer containing benzophenone group.

The warm melt pressure-sensitive adhesive is easy to cross-link under UV irradiation. The advantage is that there is no need to add photoinitiator and there is no problem of residual initiator.

It can warm melt coating at low temperature (120~140 ℃), low VOC, low odor, no skin irritation, and good thermal stability. The composition of pressure-sensitive adhesive tape is a special type of adhesive, that is, the adhesive liquid is coated on the substrate to be processed into a strip and made into a reel for supply, including solvent-activated adhesive tape, heated adhesive tape and pressure-sensitive adhesive tape. For example, the rubber paste and electrical insulating adhesive used daily in medicine belong to pressure-sensitive adhesive tape. The composition of pressure-sensitive adhesive tape ① pressure-sensitive adhesive ② base material ③ bottom treatment agent ④ back treatment agent ⑤ isolation paper pressure-sensitive adhesive mainly consists of rubber type and resin type.

For example, polyacrylate or polyethylene ether, the base material is required to be uniform, with small elasticity and good solvent wettability, including:
(1) Fabrics such as cotton cloth, glass cloth or non-woven fabric.
⑵ Plastic films such as PE, PP, PVC and polyester films.
(3) Paper, such as kraft paper, cellophane, etc.

The original degree of the base material is between 0.1 and 0.5. The role of the primer is to increase the adhesion strength between the adhesive and the base material, so that when the adhesive tape is removed, it will not lead to the separation of the adhesive and the base material and contaminate the adhered surface, and make the adhesive tape reusable. The commonly used bottom treatment agent is chloroprene rubber partially vulcanized with isocyanate and modified chlorinated rubber. The back treatment agent is generally made of polyacrylate, PVC, cellulose derivatives or organosilicon compounds and other materials. It can act as a isolating agent. If a layer of isolating paper such as semi-rigid PVC film, PP film or kraft paper must be added to the double-sided adhesive tape, the adhesive properties of the pressure-sensitive adhesive can be bonded with finger pressure without heating, It is a kind of adhesive with peel strength, and its adhesion characteristics are four major factors: cohesive strength of T (fast adhesion) adhesive layer; K-adhesion is the adhesion between adhesive and substrate.