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Preparation method of TDI tripolymer bright light curing agent with low free monomer content

A technology of monomer content and trimer, applied in the direction of polyurea/polyurethane coatings, coatings, etc., can solve the problems of easy production of high polymers, non-discharge, long time, etc., and achieve good scratch resistance and scratch resistance The effect of good wound and wide compatibility

Inactive Publication Date: 2018-06-26
QINGDAO XIANGZHI ELECTRONICS TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the high-vacuum thin film evaporation method requires too much investment and requires high process control. At present, the removal process and equipment problems of this method have not been well resolved in China. The content of free isocyanate monomers in most domestic TDI curing agents seriously exceeds the standard. TDI It is difficult to achieve the content within 0.5%, mostly around 1%
This method is an improved process of solvent extraction. Unreacted free isocyanate monomers can be dissolved in mixed hydrocarbons (such as petroleum ether, dimethyl carbonate, n-hexane, cyclohexanebenzene or their mixtures), while the curing agent polymer is It cannot be dissolved and separated from the bottom layer, and then mixed with a hydrocarbon solvent in the upper layer to continue to add a catalyst to react, but it is difficult to control the reaction in a kettle with stirring, and it is easy to produce high polymers or even gels; free isocyanate monohydrates without stirring It is difficult for the body to fully respond
And ethyl acetate, butyl acetate boiling point is low, very easy to form azeotrope with mixed hydrocarbon, conventional underpressure distillation is difficult to remove mixed hydrocarbon, then constantly add and waste a large amount of ethyl acetate, butyl acetate; When distilling, the temperature must be raised, and the time is long. The curing agent in the kettle does not know whether it is still a curing agent under the catalyst and high temperature; in addition, the distilled solvent contains esters and free monomers, which can neither be used nor discharged. become a problem, so how to recover the solvent is difficult
Even if the method is feasible, it is impossible to remove the residual mixed hydrocarbon solvent in the curing agent, which will eventually affect the product performance

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] In the synthesis kettle, 18 parts of 210 polyether, 40 parts of lauryl alcohol, and 448 parts of butyl acetate were added sequentially according to the weight ratio of the formula. When no water drops appear, cool down and cool down; when the temperature drops below 40°C, add 465 parts of 2,4-toluene diisocyanate, pass N2 protection, heat up to 75-80°C, keep warm for 0.5-1h, then cool down to 55°C, Add 1.6 parts of catalyst A compounded by DMP-30, potassium isooctanoate, and butyl acetate, and control the temperature at 55-65°C for 4 hours, then start to detect NCO, and then measure the NCO value every 0.5 hours; when the detected NCO At 10±0.5%, add 22 parts of n-butanol and 0.4 parts of potassium isooctanoate catalyst, and control the temperature at 55-60°C; when the detected NCO is 7.5±0.3%, stop feeding N2 and add benzoyl chloride 2.0 parts, 3.0 parts of antioxidant BHEB and adding butyl acetate to dilute to 50±2% solid content, stir for 0.5h, cool down to 40°C, fil...

Embodiment 2

[0022]In the synthesis kettle, 15 parts of 220 polyether, 42 parts of lauryl alcohol, and 435 parts of butyl acetate were sequentially added according to the weight ratio of the formula. When no water drops appear, cool down and cool down; when the temperature drops below 40°C, add 476 parts of 2,4-toluene diisocyanate, pass through N2 protection, heat up to 75-80°C, keep warm for 0.5-1h, then cool down to 55°C, Add 1.8 parts of catalyst A compounded by DMP-30, zinc naphthenate, and butyl acetate, control the temperature at 55-65°C and react for 4 hours, then start to detect NCO, and then measure the NCO value every 0.5 hours; When the NCO is 10±0.5%, add 24 parts of n-butanol and 0.6 parts of zinc naphthenate catalyst, and control the temperature at 55-60°C. When the detected NCO is 7.5±0.3%, stop feeding N2 and add 2.4 parts of phosphoric acid. 3.2 parts, antioxidant BHT and butyl acetate to dilute to 50±2% solid content, stir for 0.5h, cool down to 40°C, filter and pack.

Embodiment 3

[0024] In the synthesis kettle, according to the formula weight ratio, add 15 parts of 210 polyether, 36 parts of cetyl alcohol, and 434 parts of butyl acetate in sequence. When the temperature rises to about 108 ° C, there will be reflux, and reflux for 2 to 3 hours for dehydration. If there are no drops of water in the container, cool down; when the temperature drops below 40°C, add 482 parts of 2,4-toluene diisocyanate, pass through N2 protection, heat up to 75-80°C, keep warm for 0.5-1h, then cool down to 55°C ℃, add 1.8 parts of catalyst A compounded by PC-41, zinc isooctanoate, and butyl acetate, control the temperature at 55-65°C and react for 4 hours, then start to detect NCO, and then measure the NCO value every 0.5h; When the NCO is 10±0.5%, add 25 parts of n-butanol and 0.6 parts of zinc isooctanoate catalyst, and control the temperature at 55-60°C; when the detected NCO is 7.5±0.3%, stop feeding N and add hypophosphorous acid 2.6 parts, 10103.0 parts of antioxidant...

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Abstract

The invention relates to a preparation method of a TDI tripolymer bright light curing agent with low free monomer content. The TDI tripolymer bright light curing agent comprises the components in a formula: 2,4-toluylene diisocyanate, polyether polyol, long-chain alcohol, a catalyst A, n-butyl alcohol, a catalyst B, a polymerization inhibitor, an antioxidant and a solvent. The TDI tripolymer bright light curing agent with low free monomer content, prepared by using the preparation method, has the solid content of 50+ / -2%, the NCO value of 7.5+ / -0.3%, the viscosity (coating for 4 cups) of 25-35s, the free TDI content of smaller than or equal to 0.5% and the toluene tolerance of larger than or equal to 2, contains no aromatic hydrocarbons and has the characteristics such as environment friendliness, good scratch resistance, high glossiness and good transparency; and a polyurethane paint prepared from the TDI tripolymer bright light curing agent and a hydroxyl component has the characteristics such as high glossiness, high hardness, high transparency, good paint film scratch resistance, good leveling property, high fullness and wide intermiscibility, and the TDI tripolymer bright light curing agent is an environment-friendly curing agent for various bi-component polyester paints, polyurethane paints, decorative paints, floor paints and primers for wood products, metals, plastics and the like.

Description

technical field [0001] The invention relates to a preparation method of a polyurethane curing agent, in particular to a TDI trimer bright curing agent with low free monomer content. Background technique [0002] Two-component polyurethane coatings are generally composed of isocyanate prepolymers and hydroxyl resins, usually called curing agent components and main agent components. According to the different hydroxyl components, they can be divided into acrylic polyurethane, alkyd polyurethane, Polyester polyurethane, polyether polyurethane, epoxy polyurethane and other varieties generally have superior properties such as low film-forming temperature, strong adhesion, high hardness, good wear resistance, chemical resistance and weather resistance, and are currently the most widely used. A kind of paint, mainly used in automobile original factory paint, plastic paint, wood paint, industrial paint, anti-corrosion paint floor paint, electronic paint, fabric leather paint, printi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G18/48C08G18/30C08G18/09C08G18/66C09D175/08
CPCC08G18/092C08G18/2825C08G18/4825C09D175/08C08G2115/02
Inventor 不公告发明人
Owner QINGDAO XIANGZHI ELECTRONICS TECH CO LTD