Classification and comparison of research results

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The research results of pressure-sensitive adhesives are classified and compared. Under

5 blending/copolymerization

blending or copolymerization, pressure-sensitive adhesives can have the advantages of more than two polymers at the same time, and further improve their properties. Interpenetrating network (IPN) technology is an effective way to improve the compatibility of blends by using imported photoelectric encoder to measure the displacement of the recently developed heat insulation strip tensile testing machine. Zhou Ming et al. Modified polyacrylate pressure-sensitive adhesive with polyurethane/polyacrylate (PU/PAA) IPN technology. Due to the good heat resistance provided by polyurethane complex and good initial viscosity provided by polyacrylic acid complex, the heat resistance of the obtained pressure-sensitive adhesive can reach 125 degrees, and the mechanism of its heat resistance is discussed. A one component crosslinkable acrylate pressure-sensitive adhesive was prepared by copolymerizing a new functional monomer with acrylate to prepare a basic resin, and using IPN technology to mix and crosslink it with modified rosin and polyisocyanate compounds terminated by butanone oxime

the main performance indexes of the double-sided pressure-sensitive tape made of this adhesive are greatly improved compared with the domestic ordinary double-sided pressure-sensitive tape, and have reached the level of similar foreign products. It can be widely used for strong bonding and fixing of auto, home appliance and other parts

when acrylic monomers dissolved in rosin or hydrogenated rosin are copolymerized in lotion by one-step method, the conversion of monomers is significantly reduced due to the free radical chain transfer of tackifying resin molecules. The seed lotion is prepared by lotion copolymerization of most acrylate monomers, and then the remaining acrylate monomers with tackifying resin are added to the seed lotion for the second step of lotion copolymerization, which can significantly improve the total conversion of monomers. The properties of the prepared tackifying resin acrylate composite lotion copolymer pressure-sensitive adhesive are greatly improved compared with the one-step method. The effects of C5 petroleum resin and rosin as tackifying resins on the properties of polyacrylate pressure-sensitive adhesive were studied. The results showed that with the increase of rosin resin content, the 180 degree peel strength increased, the fast adhesion remained unchanged, and the adhesion retention decreased. With the increase of the content of petroleum resin, the 180 degree peel strength, fast adhesion and adhesion holding force decreased significantly. The adhesive with satisfactory properties was also obtained by solution copolymerization with the mixture of acrylate

copolymerization/blending is also an effective method to obtain high peel strength pressure-sensitive adhesive. The effects of the amount of acrylate (AE), vinyl acetate (VAC), acrylic acid (AA), epoxy resin and rosin modified resin in the grafted natural latex system on the properties of pressure-sensitive adhesive were studied. An optimal ratio was obtained, and the pressure-sensitive adhesive with a peel force of 1500N/M was obtained by heat treatment of the sample strip. Another typical example is the copolymerization of polyacrylic acid and casein monomers, and the synthesis of a pressure-sensitive adhesive with high peel strength by reducing the concentration of emulsifier, adding an appropriate amount of acrylic acid and through a composite self crosslinking agent such as methacrylamide. Its 180 degree peel force can reach 2210n/m at most

6 suspension polymerization platform type

takes acrylate as the main monomer, and can be made into microsphere pressure-sensitive adhesive with a certain size range through suspension polymerization. Compared with the dosage form and lotion pressure-sensitive adhesive that dissolve until the rubber pattern is torn off, it has more unique properties: ① repeated adhesion, that is, coated on the surface of the substrate (such as paper, fabric, plastic, metal, etc.), and the products (such as post itnote, protective film, etc.) have re stripping and reusability; ② Good resistance to adhesive layer transfer; ⑦ The practical bonding strength can be achieved by applying light pressure. After that, even if heavy pressure is applied, the strength will not increase too much. This kind of pressure-sensitive adhesive was perfected and developed in the late 1980s abroad

in recent years, China has also begun to study and have launched such products (post itnote). For example, Li Guoqiang and Mu Rui used isooctyl acrylate/methyl acrylate/acrylic acid as monomers respectively, and the passive needle of peroxide could not stop at any position for suspension polymerization to obtain microsphere pressure-sensitive adhesive with performance up to the level of similar foreign products. At present, it has been mass produced

7 hot melt polymerized platform type

hot melt pressure sensitive adhesive (HMPSA) has the dual characteristics of hot melt and pressure-sensitive. It can be coated in the molten state, cooled and hardened, and then quickly bonded with light pressure. Hot melt pressure-sensitive adhesive does not contain organic solvents, does not pollute the environment, and is simple to manufacture, convenient to use, and widely used. Due to the pressure of environmental protection and the performance defects of aqueous solution system, the importance of hot melt adhesive is increasing, and it is expected to gradually replace solvent based pressure sensitive adhesive

styrene based thermoplastic elastomer is styrene diene styrene block copolymer, abbreviated as SDS. If diene is butadiene, the copolymer is SBS; if isoprene, it is sis. Because SDS structure contains plastic and rubber segments, it has the properties of both, that is, the mechanical properties of rubber and the technological properties of plastic, which is very suitable for the preparation of hot-melt pressure-sensitive adhesive. After the commercialization of SBS and SIS by shell chemical company of the United States in 1965, it began to be used in the manufacture of hot-melt pressure-sensitive adhesive, and SIS was used as the preferred raw material of hot-melt pressure-sensitive adhesive

the research and production of hot-melt pressure-sensitive adhesive in China started late, and the annual output was only 3000 tons by 1995, which was mainly used in the production of sanitary napkins and diapers. At present, there is a certain development, and the application field is also expanding. SDS hot melt pressure-sensitive adhesive can be used to manufacture general pressure-sensitive adhesive products, as well as cleaning tools, children's toys, crafts, PVC floor tiles, etc. it can also be used for the bonding of car cushions, backrests, carpets and other parts. A troop in Urumqi, Xinjiang, used SDS type hot-melt pressure-sensitive adhesive to repair butyl rubber chemical protective clothing. The effect was very good, solved the problems that had not been solved for many years, and passed the technical appraisal of the General Logistics Department. SDS hot melt pressure sensitive adhesive with excellent comprehensive properties was successfully developed by using the mixture of SIS and SBS. Several properties of SBS thermoplastic elastomer were improved by adding tackifier, plasticizer and other fillers. Hot melt pressure-sensitive adhesive with shear strength of 136n/cm2, 180 degree peel force of 1164n/M and adhesion holding force of more than 12h was obtained

8 crosslinked/curable

crosslinked/curable pressure-sensitive adhesive is a kind of adhesive that has the initial viscosity of pressure-sensitive adhesive at the initial stage of bonding and plays the role of temporary positioning bonding. After bonding, it is crosslinked and cured under appropriate conditions such as light, heating, pressure, moisture and radiation, so that its bonding strength and heat creep resistance can be improved. Many kinds of pressure-sensitive adhesives have been developed abroad, but due to the limitations of their technology and varieties, domestic research is still less

this kind of pressure-sensitive adhesive has attracted more attention in recent years because of its high cohesion and high temperature resistance. On the basis of up/PAA interpenetrating pressure-sensitive adhesive, Zhou Ming et al. Made nc0 active group excessive, and then cured it under wet gas or heating conditions to obtain a cured pressure-sensitive adhesive. The adhesive not only has good initial performance, its performance is significantly improved after curing, but also can maintain a high service temperature, and the short-term service temperature can even reach 150~250 degrees

in addition, Xu Yan and others [23] also used NR and SBS as the main raw materials and adopted the technical route of initial shallow crosslinking and later curing to prepare a special heat curing pressure-sensitive adhesive for electronic capacitors. The obtained pressure-sensitive adhesive has excellent performance, especially heat resistance. The melting temperature can reach more than 170 ℃. At 125 ℃ for 4.5H or 170~uo ℃ for a short time, the capacitor pasted by the adhesive tape will not fall off, and there is no residual adhesive on the lead wire, and the cost is low, which is comparable to the imported pressure-sensitive adhesive of the same kind

in addition, biosynthesis and hydrosol pressure-sensitive adhesives have developed rapidly abroad, but they are still in the exploratory stage in China, so there are few reports in this regard, so they are not introduced here

in recent years, with the rapid development of China's economy, the demand for pressure-sensitive adhesive and its products in packaging and related industries is increasing, and the development of pressure-sensitive adhesive shows a trend of rapid change. The emergence of new synthesis methods and crosslinking curing methods makes it possible to synthesize pressure-sensitive adhesives with high performance and meeting the requirements of environmental protection and safety. It can be expected that the research of pressure-sensitive adhesives and their products will also receive more extensive attention, and the latest achievements in other fields will be further adopted to make them develop in the direction of functionalization and diversification, gradually changing the situation that the domestic field has been in a single variety for a long time, and many special adhesives depend on import

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