(1) Performance and application The resin containing many repeated active groups in the main chain is called polyurethane, or polyurethane for short. The structure of polyurethane and polyamide is very similar, except that the active group of the former has one more oxygen atom than the active group of the latter, so the performance of the two has many similarities.
Polyurethane adhesive is composed of isocyanate and polyester or polyether. Good adhesion, adjust the types and proportions of components during use, and obtain flexible to hard adhesive layers. It can be cured at high temperature or at room temperature, and has a wide range of applications.
Polyurethane adhesive has the characteristics of water resistance, oil resistance, solvent resistance, ozone resistance, bacteria resistance, etc., especially at low temperature with excellent bonding strength, so it is Promising low-temperature adhesives.
Polyurethane adhesives work well on metal, wood, rubber, fabric, most plastics (especially PVC which contains a lot of plasticizers) Affinity. It is widely used in the lamination of adhesive fabrics for light packaging materials, the manufacture of composite materials, electrostatic flocking, the manufacture of non-woven fabrics, the manufacture of shoes, rubber products and sealants, etc. It is expected that there will be greater development in the future.
(2) Caprolactone polyol polyurethane adhesive This type of adhesive is obtained by the reaction of caprolactone and diol. Compared with it, it has the following advantages: ①good color; ②uniform structure, uniform molecular weight distribution, ③only active hydroxyl groups at the end groups, and the number of functional groups is clear; ④hydrolysis resistance, low temperature softness; ⑤Because of low viscosity, almost 100% It can be cured and compatible with a wide range of solvents. ⑥Compared with polyethers, it has excellent outdoor durability.
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