Polyurethane adhesive is an important part of the rapidly developing polyurethane resin. It has excellent performance and has been widely used in many aspects. It is one of the important synthetic adhesives.
Polyurethane adhesive has excellent shear strength and impact resistance, is suitable for various structural bonding fields, and has excellent flexibility.
Polyurethane adhesive has excellent rubber properties and can be adapted to bonding base materials with different thermal expansion coefficients. A soft and hard transition layer is formed between the base materials, which not only has strong adhesion, but also has excellent buffering and shock-absorbing functions. The low temperature performance of polyurethane adhesives exceeds that of other adhesives.
1. Polyurethane adhesiveAdvantages:
1. Strong adhesion and wide application range
Due to the Groupcan be used with Various functional groups containing active hydrogen react to form interfacial chemical bonds, so they have strong adhesion to various materials. It can not only bond porous materials such as foam plastics, ceramics, wood, fabrics, but also various metals, inorganic materials, plastics, rubber and leather, etc. It is an adhesive with a wide range of applications.
2. Excellent ‘s low temperature resistance
At very low temperatures, general polymer materials transform into a glassy state and become brittle, while polyurethane adhesives even at -250℃The following can also maintain a high peel strength, while its shear strength decreases as the temperature decreasesLarge Added.
2. Disadvantages of polyurethane adhesive：
1 , the toxicity of free isocyanate monomers in polyurethane adhesivesveryLarge. There are two ways of harming the human body . First, the steam evaporated in the air has a negative impact on the Irritation to human respiratory tract and eyes; the other is damage caused by isocyanate liquid contacting skin and mucous membranes. A variety of polyisocyanates are used in the polyurethane industry, and some of the liquid diisocyanates have higher volatility, such as toluene diisocyanate commonly used in flexible polyurethane foam manufacturing and hexamethylene diisocyanate commonly used in the coating industry. They have high volatility when heated. Higher volatility. However, the polyurethane adhesive after AB glue mixing reaction is non-toxic after forming a solid state. Polyurethane adhesiveis moving toward green adhesives develop.
2. Polyurethane adhesives usually cure slowly at room temperature, sometimes taking several days to fully cure. If multi-component composite is used, the room temperature curing time can be significantly shortened, making it more convenient and applicable.
3. The high temperature resistance of polyurethane glue is far inferior to its low temperature resistance. If it is used for food packaging composite film, its retort resistance is required. The introduction of nanoparticles can significantly improve its heat resistance, tensile strength, shear strength and peel strength. However, the addition of nanomaterials should be appropriate. If too much is added, the orderly arrangement in some molecules may be destroyed, resulting in a decrease in mechanical properties.
Title of this article: Advantages and Disadvantages of Polyurethane Adhesives
Source of this article: http://www.wellgo.com. cn/newb/information_2358.shtml
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