PUR hot melt adhesive
preparation method, the steps are as follows: step 1: weighing various components according to the formula ratio of weighing PUR hot melt adhesive, which, according to the needs, functional additives selected components, and to determine the proportion of each component.
Step 2: raw materials in addition to water will polyether polyols, thermoplastic resin into the reaction kettle, vacuum mixing under 120 ~ 130 ℃ dissolve 2 h;
Then, liquid crystalline polyester polyols non-crystalline polyester polyols, solid non-crystalline polyester polyols, into the reaction kettle, in the 120 -
130 ℃ under the condition of nitrogen, vacuum stirring except 1 h above water, until the water content of less than 500 PPM, get a mixture.
Step 3: synthesis will be a mixture temperature to 80 ℃ under the condition of nitrogen, join in advance has been molten pure isocyanate monomer liquid, temperature or already back to normal temperature of pure powder of isocyanate monomer, in 80 -
Vacuum stirring reaction for 2 h under 100 ℃, the test free NCO content, if do not conform to the requirements, continue to reaction, until the free NCO content conform to the requirements, obtain secondary mixture.
Step 4: add supplementary materials will be the catalyst, functional additives under the condition of nitrogen, join the described secondary mixture, vacuum mixing 15 ~ 30 min, structure of PUR hot melt glue.
Step 5: feeding to PUR hot melt adhesive temperature to 110 ℃, after row of the bubble, feeding system.
This PUR hot melt adhesive can be applied to mobile phones, tablets and other electronic products of the battery cover, TP, camera decoration parts loci of adhesive, also can be applied to refrigerators, washing machines, induction cooker and other shell or panel of adhesive, application range is very wide.
This product can be applied to commonly used 18 -
22, needle point glue, glue pressure according to different needles, dispensing velocity, point glue temperature is different, generally in 0.
6 mpa, melt temperature - in 90
Way of curing the product the same as the general PUR hot melt glue, namely first physical curing provide initial strength, chemical curing with strength.
The product of common materials such as PC, ABS, PVC and other engineering plastics, aluminum, stainless steel, magnets, such as metal, as well as various types of printing ink has good adhesion
This product can withstand high temperature above 100 ℃, -
Below 40 ℃ low temperature, under high temperature and high humidity environment for a long time, the intensity attenuation.
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