Water based polyurethane is a kind of block copolymer containing soft segment and hard segment. The soft segment is composed of oligomer polyols, and the hard segment is composed of polyisocyanate and chain extender. It has excellent wear resistance, oil resistance, low temperature resistance, aging resistance and chemical resistance.At present, the water based polyurethane emulsion on the market is mainly used for leather, adhesives and coatings, and its crosslinked solidifiers are mainly attached to fabrics and rubber and other surfaces to play the role of surface modification or bonding.Generally speaking, the research of polyurethane latex products mainly focuses on a single property such as flexibility and adhesion. However, when polyurethane latex products are used, the comprehensive properties including tensile strength, elongation at break, permanent deformation at break and tear strength are very high. Generally speaking, the research of polyurethane latex products mainly focuses on a single property such as flexibility and adhesion. However, when polyurethane latex products are used, the comprehensive properties including tensile strength, elongation at break, permanent deformation at break and tear strength are very high. Latex products are widely used in the national economy, according to incomplete statistics, different types and different specifications of latex products up to more than 40 thousand, common latex products are condoms, gloves, rubber hose, toy balloons and sponge products, etc., the main raw material for the preparation of latex products is natural latex. Natural latex products have the advantages of good elasticity and flexibility, but there are the following four deficiencies. (1)The heterologous protein in natural latex products will make some people allergic; (2)Natural latex products in the vulcanization process will produce carcinogenic N-nitrosamines; (3)Poor densification of natural latex products and insufficient virus isolation effect will lead to the risk of infection of users. Some studies have shown that natural latex medical surgical gloves cannot prevent the transmission of hepatitis B virus during surgery. (4)The aging resistance of natural latex products is insufficient. Heat, oxygen, light, acid-base compounds and variable metal ions will greatly accelerate the aging of natural latex products, and then make it lose its performance. Waterborne polyurethane latex products can effectively make up for the shortage of conventional natural latex products. Waterborne polyurethane latex products have good biocompatibility and virus barrier properties. Waterborne polyurethane latex is an ideal material to replace natural latex in latex products. The raw materials of waterborne polyurethane latex products, natural latex products and other synthetic latex products belong to ionic type, which can be prepared by the universal latex product molding process. Sinograce Chemical production for know pol...

Differentiated by medium Waterborne polyurethane: A new type of polyurethane system using water instead of organic solvent as dispersion medium, also known as water dispersed polyurethane, water polyurethane or water based polyurethane. Oily polyurethane: polyurethane system with organic solvent as dispersion medium, polyurethane system with thermoplastic linear structure. Distinguish by appearance Waterborne polyurethane is mostly opalescent transparent, blue translucent. Oil-based polyurethane is transparent. According to environmental protection distinction Waterborne polyurethane is based on water as a dispersion medium, VOC (volatile organic compounds) content is very low, minimal environmental pollution; Oily polyurethane uses organic solvent (toluene, xylene, industrial alcohol, etc.) as dispersion medium.Toluene and xylene are important items of product environmental monitoring. Oil-based polyurethane is not environmentally friendly compared with water-based polyurethane in the production, use and waste treatment process. There is a strong pungent smell and organic gas volatilization.

water-base adhesive With the development of society, the quality of glue has been pushed to a high point, which also led to the development of water-based glue. At present, the environmental protection industry is in a stage of rapid development. People pay more and more attention to health and environmental protection issues. The chemical glue industry is also in a stage of rapid change, and water based adhesive gradually begins to become the mainstream of the market. Let's briefly talk about the characteristics of water-based glue: Environment protecting The water-based adhesive is made of high polymer, water-soluble resin and other main raw materials, with water as the solvent. It is non-flammable and easy to clean up. It conforms to FDA, SGS, ROHS and other certifications. Waterborne adhesive can be safely used for packaging of food, medicine, alcohol, tobacco, children's toys and so on. The machine can be cleaned with water after using glue, not only to improve the production environment, but also to ensure the health of production personnel. Safe and reliable In practical application, some packaging and printing enterprises lack sufficient understanding of water-based adhesives, which causes some quality problems. The preparation method and production process of different types of water-based adhesives (semi-oil semi-water and pure water) are different, that is, the application index is different. The most important application indexes of water-based adhesives in packaging and printing industry include bond strength, high/low temperature resistance, moisture resistance and adhesion. Some packaging and printing enterprises reflect: Some water-based adhesives will be degumming soon after gluing; The viscosity is unstable, sometimes the bond is firm, sometimes it is not on; It works well in hot weather, but it doesn't work in cold weather. In fact, these defects occur because of the above four application indicators are not up to standard. And water-based glue, broken paper fiber in more than 90%, strong adhesion, good temperature resistance [at high temperature (60℃), low temperature (-20℃), high temperature and high humidity (60℃, 85%RH) and constant temperature conditions 48h do not unglue foaming]. Versatility and innovation  Water based adhesive products are not only easy to operate, but also widely used. At present, water-based adhesive is mainly used for bonding between UV paper/paper, polished paper/paper, PET/ paper, BOPP/ paper, PVC/ paper, coated paper/gray board, special paper/plastic box, coated paper/gray board and other substrates. Each water-based adhesive has its "inherent characteristics", which mainly include appearance (product appearance and film appearance), solid content, PH value, solvent ratio, opening time, high/low temperature resistance, viscosity, etc. The bonding methods of water-based adhesives are generally divided into three kinds: machine adhesive, hand adhesive, machine adhesive and hand adhesive. Differ...

Because the water glue is bonded together by the film forming principle, its compound effect is very stable, and the product can be cut immediately.If the composite quality is bad because of the process or substrate, it can also be seen in the first time off the machine, and it will not be found after mass production.Therefore, the composite packaging products use water-based glue instead of solvent compound glue, not only to meet the requirements of safety, health and environmental protection, shorten the delivery cycle, but also to reduce the transfer of aluminum plating film.But in the use of some process control points to pay special attention to, according to the long-term use experience of the summary, for the peer reference.But in the use of some process control points to pay special attention to, according to the long-term use experience of the summary, for the peer reference. 1, because the amount of water-based glue is very small, the rubber roller should choose the cable dense and shallow laser engraving roll. Usually 200 wire / 35μdepth, the laser roller has a large mesh shape opening, which ensures the glue is transferred to the film better 2.Before using water glue, be sure to stir the glue slowly in the bucket for 5 to 10 minutes to ensure that the various additives in the glue are mixed evenly. 3.Before gluing to detect the surface tension of the film, it is best to use Dyne liquid, rather than Dyne pen. Different film surface tension requirements are different, specific reference is as follows: Material Name Corona value PET ≥50dyne BOPA ≥52dyne BOPP ≥38dyne CPP ≥38dyne PE ≥38dyne 4. as far as possible to use the reverse rotation of the rubber roller. We have observed in the actual production that the reverse flattening roller has a great impact on the appearance, especially when the composite transparent non-printing or non-full-plate pattern products, the appearance effect can be more visible. By adjusting the speed of the rubber roller, the composite appearance can achieve excellent results. 5, the oven temperature is set from low to high, a section of temperature is generally 70~75℃, 75~80℃, 80~85℃ (the temperature to the set temperature can be turned on) The inlet air and exhaust air of the oven should be put to the maximum. The effect of the air volume on the drying of water-based glue is more important than the temperature. The temperature of some composite rollers is generally set to 70~80℃, and the pressure of composite rollers can be set to be larger. 6.It is best to have a circulating pump between the glue tank and the glue bucket. Clean up the pump before use 7.In order to prevent blocking, the scraper should be stopped and the upper rubber roller should be soaked in the glue to keep rotating. 8.the machine speed is too high will produce bubbles, you can put a glue stick in the groove. 9.After use, wipe the glue on the rubber roller with water first, and then clean it thoroughly with ethyl ester. If the plate has been...