The hottest two-component polyurethane adhesive wi

2022-07-24
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The two-component polyurethane adhesive will still dominate the market

in the flexible packaging composite, the two-component polyurethane adhesive is a sweet cake. In the dry composite, the packaging using the two-component polyurethane adhesive composite is not only exquisite, but also not easy to be damaged in the process of transportation and storage. Therefore, the application of two-component polyurethane adhesive in dry compounding has become the main technology of flexible packaging compounding

the two-component polyurethane adhesive uses ethyl acetate as the solvent, so it is an ester soluble polyurethane adhesive. With the rapid rise of other alcohol soluble, water-based and solvent-free polyurethane adhesives, unexpected variables and factors difficult to control have been added to the flexible packaging polyurethane adhesive market. What is the future of two-component polyurethane adhesives? Will other polyurethane adhesives replace two-component polyurethane adhesives

two component polyurethane adhesive is still the mainstream product

development process

from the 1970s to the early 1980s, most of the composite of ordinary packaging used one component rubber adhesive, and only two-component polyurethane adhesive was used for high-end packaging. After the 1980s, the compounding was basically changed to two groups. If the change-over switch was turned to the fast reverse gear, the polyurethane adhesive was the dominant and the extrusion composite adhesive was the auxiliary

China's two-component polyurethane adhesive was developed in the middle and late 1980s. At that time, several adhesive factories and research institutes such as Zhejiang New Oriental, Beijing Research Institute of chemical industry and Shanghai lieyin were engaged in research and development. With the progress and development of technology, the quality of two-component polyurethane adhesive produced in China has risen steadily, and the price is getting lower and lower, gradually winning most of the domestic market

advantages of two-component polyurethane adhesive

the following advantages of two-component polyurethane adhesive make it the leading product in the polyurethane adhesive market in the next 10 years

(1) good bonding effect of the Ministry of environmental protection of China leading the preparation of the new regulations. It has high peel strength and is applicable to a wide range of substrates. It can be used for the composite of paper, pet, OPP, NY, PE, CPP and aluminum foil materials with good composite quality and high composite strength

(2) outstanding dielectric resistance. It can resist the corrosion of acid, alkali, oil, spicy and various oxides and chemicals

(3) good cold resistance and heat resistance. Many food packages require low-temperature preservation or high-temperature sterilization at 121 ~ 135 ℃, and the two-component polyurethane adhesive can still maintain good peel strength under the above conditions

requirements for use

the main agent of the two-component polyurethane adhesive is polycondensated from adipic acid and ethylene glycol, and the curing agent is polymerized from toluene diisocyanate (TDI) and trimethylolpropane. It is worth noting that TDI will become toluene diamine (TDA) after high-temperature hydrolysis, and TDA is a carcinogen

after the composite reaction, a little isocyanate will remain in the polyurethane adhesive. After high temperature cooking, the isocyanate will be transferred to the food through the film and hydrolyzed to form TDA. Therefore, if the packaging is used improperly, the food will have potential cancer risk. In view of this situation, the US Food and Drug Administration (FDA) prohibits the application of aromatic polyurethane adhesives in cooking packaging. Although China, Japan, Europe and other countries and regions do not expressly prohibit the use of two-component polyurethane adhesives, they also have certain restrictions on the content of TDA. The TDA content required in China shall not exceed 0.004mg/l to reduce the potential hazards in packaging

development direction

as the solvent of two-component polyurethane adhesive is ethyl acetate, which is not completely environmentally friendly and flammable, the development direction of ester soluble polyurethane adhesive is high solid content and low viscosity. From the analysis of domestic production status and economic development trend, in the next 10 years, ester soluble polyurethane adhesives will account for about 70% of polyurethane adhesives, and the market can measure and record the share of characteristic curve field of data in the process of impact

other adhesives cannot become substitutes

alcohol soluble polyurethane adhesive: the prospect is not optimistic. Alcohol soluble polyurethane adhesive is a polyurethane adhesive developed in recent years with ethanol as the solvent. Alcohol soluble polyurethane adhesive has the following advantages

(1) it does not contain free isocyanate monomer, which improves the operating environment

(2) it is insensitive to moisture, which improves the stability and adaptability of the adhesive

(3) using industrial alcohol as solvent, the production cost is reduced

(4) it has excellent composite adaptability when used with alcohol soluble polyurethane printing ink

(5) low residual solvent in composite membrane products

however, the development of alcohol soluble polyurethane adhesive is not optimistic, because although alcohol soluble polyurethane adhesive has taken a step in environmental protection, strictly speaking, it is not completely environmental friendly adhesive, because ethanol is also an organic solvent

in addition, at present, alcohol soluble polyurethane adhesive is only used in the composite packaging of ordinary dry food. According to the current technology and the properties of alcohol soluble polyurethane adhesive, it can not reach the peel strength and cooking performance of ester soluble polyurethane adhesive. Therefore, the development prospect of jgj98 (2) 000 urethane adhesive is not optimistic

waterborne polyurethane adhesive: high cost and energy consumption

waterborne polyurethane adhesive is made by dispersing polyurethane resin in water to form a lotion or dissolving hydrophilic groups on the splicing of polyurethane resin in aqueous solution. Waterborne polyurethane adhesive is non combustible, non-toxic, non polluting to the environment, and has wide adaptability. However, it is still inferior to ester soluble polyurethane adhesive in terms of composite strength and weather resistance. Cooking technology is also a difficult problem at present. Because of its long drying time, high energy consumption and cost, it can not be further developed in the current situation of increasing energy shortage

therefore, although waterborne polyurethane adhesive has certain development space, it will not replace ester soluble polyurethane adhesive in the next 10 years due to cost and energy consumption

solventless polyurethane adhesive: it will not be developed significantly until 10 years later. In fact, solventless polyurethane adhesive is the real environmental friendly adhesive. At present, solventless adhesive has been widely used abroad. It has the following advantages

(1) no pollution

(2) no solvent volatilization drying process is required, which reduces energy consumption

(3) there is no problem of residual solvent in the composite products, which also reduces the risk of fire in the production process

solventless polyurethane adhesive is applicable to various types of plastic composite packaging. It also has good bonding effect on aluminum foil. Its content physical properties and high temperature cooking resistance are the same as those of ester soluble polyurethane adhesive, and its peel strength is high

to sum up, alcohol soluble polyurethane adhesives will not be developed in the next 10 years, and waterborne polyurethane adhesives will still not be able to compete with ester soluble polyurethane adhesives; After 10 years, the ester soluble polyurethane adhesive will be gradually reduced, the water-based adhesive has a certain development space, and the solvent-free polyurethane adhesive will be gradually promoted in China

source: PRINT world

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