• Analysis on the application of waterborne polyurethane (WPU) in coatings
    Analysis on the application of waterborne polyurethane (WPU) in coatings

    2019-01-17

    Waterborne polyurethane Analysis on the application of waterborne polyurethane (WPU) in coatings Waterborne polyurethane is used in waterborne wood coatings, which is expected to obtain excellent film hardness, heat resistance and dielectric properties, and good film-forming properties. The higher the degree of microphase separation of aqueous polyurethane, the greater the difference of softening temperature, the better the film formation and heat resistance, but for wood coatings, film hardness and resistance to media is also an important measure of the performance of the index. In order to improve the dielectric resistance and the hardness of the coating, it is necessary to increase the crosslinking density and increase the proportion of the rigid segments in the molecular segments, it certainly will reduce the flexibility and relative molecular mass of the waterborne polyurethane molecules. These are not conducive to the micro phase separation, the mixing degree increased, unfavorable to the film. The research route is of high hardness, low molecular weight (less than 1000) polyester polyurethane preparation to obtain a high degree of crosslinking, heat resistance, chemical resistance and film hardness.  At the same time, with good flexibility, high molecular weight (more than 2000) linear polyester preparation or low branching polyurethane, to improve the degree of microphase separation, the coating has excellent film-forming properties, reduce film-forming agent dosage, improve the film hardness rise velocity. And through these 2 kinds of polyurethane copolymerization to obtain comprehensive performance.   Test method for aqueous polyurethane dispersion Huajinsi  The aqueous poly (ethylene glycol) dispersion 4188/4100 (FOD) does not contain any free OH group, but they are still able to react with poly (ethylene glycol) as a hardening agent. This is due to the reaction of the amide backbone of the polyurethane dispersion. Because we can not calculate correctly, we can only recommend the following methods: 2, 4, 6, 8, 10, 12, 16%, a combination of isocyanate curing agent to quickly test. Aqueous ammonia fat dispersion with different curing agent, stirring for 10 minutes and then construction in plastic or wood substrate. After drying at room temperature on the 7 film angels bridge complete placement. 7 days after the test of chemical resistance (water, alcohol, coffee, fruit pulp, etc.) and mechanical properties (pendulum hardness, pencil hardness, scratch resistance, etc.), the results can be seen how much hardener. In this case, the hardener with 10~12% can achieve good film performance. The relationship between hardening agent weight and paint performance of hydroxylamine PUD binder Hardening agent Film state Film properties PUD binder No hardener: bad alcohol resistance Flexible elastic membrane Not very scratch resistant PUD binder Add 2% hardener: bad alcohol resi...

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  • Adhesive for packaging
    Adhesive for packaging

    2018-09-07

    Paper packaging is divided into two categories, one is pure paper packaging, such as corrugated boxes, paper drums, cartons and paper bags which is currently the largest widest used packaging. The other is paper-based composite material packaging, such as paper / plastic composite box (bag), paper / aluminum foil composite box (bag), paper / wood composite material box (box). 1. Adhesive for plain paper This kind of packaging with more adhesive is starch gel and polymer emulsion. 2. Paper - based adhesive for composite materials As long as the molecular structure design of Acrylic Emulsion Modified Composite Adhesive is reasonable, can overcome all of its shortcomings while having the advantages of VAE emulsion modified adhesives .Peel fastness is very good, the cost is also significantly reduced. Not only can paper / BOPP, but also composite paper / PET, paper / PVC, paper / aluminum foil, paper / paper, and has formed a large-scale production and sales. 3. The development direction of adhesive for paper packaging High solid content of water-based emulsion glue, water-based and solvent-free polyurethane adhesive, biodegradable hot melt adhesive, green multi-functional composite rubber is the future development trend of green paper and plastic adhesives.

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  • Water-based adhesives
    Water-based adhesives

    2018-07-17

    Introduction: Water-based adhesives to water as a dispersion medium adhesive, is a major category of environmentally friendly adhesives. The solvent-based adhesive is a homogeneous system with organic solvents such as benzene and toluene as the dispersion medium. The water-based adhesive is a heterogeneous system with water as the dispersion medium. Classification: Water as a dispersion medium adhesive is divided into water-soluble adhesive, water-based adhesive and water-based adhesive. Water-based adhesives are mainly divided into water-based polyurethane adhesives, water-based polyacrylate adhesives, water-based epoxy adhesives, water-based silicone adhesives, polyvinyl acetate emulsion,chloroprene latex. Water-based adhesives mainly include phenolic, urea-formaldehyde, melamine formaldehyde, polyvinyl acetate emulsion, EVA emulsion, polyacrylate emulsion, water-based polyurethane, and water-emulsion epoxy, the latter in the domestic stage. Advantages and disadvantages: Water-based adhesive is one of the development trend of adhesives, compared with solvent-based glue, has advantages of solvent-free release, in line with environmental requirements, low cost, non-combustible, the use of security and so on. Its solid content is relatively high, up to 50% to 60%. But because of the slow evaporation of water, the curing slow or need to heat drying equipment. Many government departments issued a decree to limit the use of volatile organic compounds (VOCs), adhesives from the solvent to the water-based type of transformation has become inevitable at home and abroad are vigorously research and development.

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  • What is plastic film?
    What is plastic film?

    2018-06-26

    Polymeric materials are made from high temperature reaction polymerization of water-based plastic film, the product is the ideal composite adhesive of printing color printing industry , widely used in paper and plastic film, paper and paper composite, non-polar material or weak polarity. It has a high bonding strength, weather resistance and excellent water resistance, free of formaldehyde, benzene. 1.  Product Features a. Good early sticky b. Good water & weather resistant c. High bond strength 2. Product Usage Widely used in oil paper, polishing paper, copper paper, white paper and other materials between the composite and the corresponding composite material of printing color printing packaging industry.

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