Polyester polyol for synthesizing moisture cured polyurethane hot melt adhesives

A technology of polyurethane hot melt adhesive and polyester polyol, applied in the field of polyester polyol, which can solve the problems of low molecular weight of polyester, increased bubbles, prolonged moisture curing time, etc.

Active Publication Date: 2016-08-31
ZHEJIANG JOYA POLYMER TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The problem brought by this method is: due to the chemical crosslinking of the active isocyanate groups inside the colloid under high temperature conditions (over 130°C), the viscosity of the melt adhesive fluctuates or even rises rapidly, and at the same time, the high melt temperature makes the colloid coating It is easy to cause heat deformation of the adherend when it is covered on the surface of the heat-sensitive adherend
The problem with this method is that the high isocyanate content prolongs the moisture curing time after the colloid is applied, and more bubbles are generated during curing
However, due to the use of polyester with low molecular weight and high hydroxyl value, too much isocyanate is consumed during the synthesis process, which causes the hardness of the moisture-cured polyurethane hot-melt adhesive to increase greatly, and the free isocyanate increases, and the bubbles generated during moisture-curing increase significantly. unacceptable
[0005] Using polyester with higher molecular weight (such as hydroxyl value less than 30mg / KOH, average molecular weight greater than 3500g / mol) to synthesize moisture-cured polyurethane hot melt adhesive can obtain suitable isocyanate content (such as NCO% is 2 to 5) and good Moisture curing effect, but the polyester itself has a high viscosity, resulting in a correspondingly high viscosity of the synthetic moisture-curing polyurethane hot melt adhesive, which is difficult to coat

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] Add 500 g of Corfree M1 mixed acids (main components are 1,10-sebacic acid, 1,11-undecane di A mixture of acid 1,12-dodecanedioic acid, average molecular weight 220 g / mol), 1,5-pentanediol 200g, 2-butyl-2-ethylpropanediol 120g, alkyd-acid ratio is 1.18, while heating Start stirring; when the temperature rises to 190°C, start to distill water, continue to heat up until the internal temperature reaches 220°C, when the water to be distilled is close to the theoretical amount, and when the measured hydroxyl value is less than 15mg / KOH, start to distill the reaction product under reduced pressure For oligomers and excess alcohol, when the distillate decreases or slows down, depressurize and carry out high-vacuum reaction, keep the system pressure below 80Pa, after 3 hours of reaction time, continuously sample and measure the hydroxyl value, when the hydroxyl value reaches 24mg / KOH When the polycondensation reaction ends. Under the protection of nitrogen, release the vacuum ...

Embodiment 2

[0020] Add 500 g of Corfree M1 mixed acids (main components are 1,10-sebacic acid, 1,11-undecane di A mixture of acid 1,12-dodecanedioic acid, average molecular weight 220 g / mol), 1,5-pentanediol 120g, 2-butyl-2-ethylpropanediol 230g, alkyd-acid ratio 1.14, while heating Start stirring; when the temperature rises to 190°C, start to distill water, continue to heat up until the internal temperature reaches 220°C, when the water to be distilled is close to the theoretical amount, and when the measured hydroxyl value is less than 15mg / KOH, start to distill the reaction product under reduced pressure For oligomers and excess alcohol, when the distillate decreases or slows down, depressurize and carry out high-vacuum reaction, keep the system pressure below 80Pa, after 3 hours of reaction time, continuously sample and measure the hydroxyl value, when the hydroxyl value reaches 24mg / KOH When the polycondensation reaction ends. Under the protection of nitrogen, release the vacuum dis...

Embodiment 3

[0022] Add 500 g of 1,11-undecanedioic acid, 200 g of 1,6-hexanediol, 2,4-diethyl- 1,5-Pentanediol 150g, alkyd ratio 1.14, start stirring at the same time as the temperature rises; when the temperature rises to 190°C, start to distill water, continue to heat up until the internal temperature reaches 220°C, when the distilled water is close to the theoretical amount, When the measured hydroxyl value is less than 15mg / KOH, the oligomers and excess alcohol generated by the reaction are distilled under reduced pressure. When the distillate decreases or slows down, the high vacuum reaction is carried out under reduced pressure, and the system pressure is kept below 80Pa. The reaction time is 3 Hours later, continuously sample and measure the hydroxyl value, and the polycondensation reaction ends when the hydroxyl value reaches 24 mg / KOH. Under the protection of nitrogen, release the vacuum discharge to obtain the polyester polyol P3. The polyester has a molecular weight of about 4...

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PUM

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Abstract

The invention relates to polyester polyol with a special structure, in particular to polyester polyol for synthesizing moisture cured polyurethane hot melt adhesives. The polyester polyol is prepared from three kinds of monomers A, B and C through esterification reaction, wherein the A is at least one kind of long straight chain binary acid, and the long straight chain binary acid refers to straight chain binary acid containing eight carbon atoms or above in the carbon chains; the B is at least one kind of long straight chain dihydric alcohol, and the long straight chain dihydric alcohol refers to the straight chain dihydric alcohol containing five carbon atoms or above in the carbon chain; the C is at least one kind of long branch chain dihydric alcohol, the long branch chain dihydric alcohol refers to dihydric alcohol with linear straight carbon chain and at least one long branch chain structure, and the long branch chain structure refers to carbon chains containing two methylene or above. The synthesized polyester polyol has the advantages of high molecular weight and low normal temperature viscosity. When the polyester polyol provided by the invention is used, the polyurethane hot melt adhesives with low melt viscosity can be generated through the reaction with isocyanate on the premise of not increasing the content of the isocyanate.

Description

technical field [0001] The invention relates to a polyester polyol with a special structure, in particular to a polyester polyol used for synthesizing moisture-curing polyurethane hot-melt adhesives. Background technique [0002] Moisture-curing polyurethane hot-melt adhesive is a kind of high-performance hot-melt adhesive product widely used at present. The main component of this type of polyurethane hot melt adhesive is an isocyanate-terminated polyurethane prepolymer formed by the reaction of polyester diol (referred to as polyester) with a molecular weight of 1000-5000 g / mol and an isocyanate compound. The prepolymer has thermal fluidity, is coated on the surface of the adherend after being heated, and is cross-linked and solidified by moisture in the air to form a bond. [0003] Since this type of adhesive has the characteristics of heating and coating, the hot melt viscosity is an important indicator of this type of adhesive. The usual way to reduce the hot-melt visc...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G63/16C08G18/42
CPCC08G18/4238C08G63/16
Inventor 贝文理叶青潘婷婷
Owner ZHEJIANG JOYA POLYMER TECH
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