Preparation method for low free toluene diisocyanate (TDI) polyurethane pre-polymer curing agent

A polyurethane prepolymer and low-free technology, applied in coatings and other directions, can solve the problems of prepolymers having no practical value, endangering the physical and mental health of builders, and lack of elasticity, and achieve low toxicity of products, increased construction time limit, and low color. Effect

Inactive Publication Date: 2013-06-05
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, these TDI-based prepolymers often contain high free monomers (free TDI), which seriously endanger the physical and mental health of builders and fail to meet the latest national saf...

Method used

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  • Preparation method for low free toluene diisocyanate (TDI) polyurethane pre-polymer curing agent
  • Preparation method for low free toluene diisocyanate (TDI) polyurethane pre-polymer curing agent
  • Preparation method for low free toluene diisocyanate (TDI) polyurethane pre-polymer curing agent

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] In a four-neck flask equipped with a thermometer, an electromagnetic stirrer, and a reflux condenser, under the protection of nitrogen, add 45g of TDI (A-1) and 474.94g of dehydrated butyl acetate (component B), keep warm in a water bath at 40°C, and stir for 10min , so that it is mixed uniformly to obtain a TDI solution. Heat and melt 11.55 g of dehydrated trihydroxypropane (TMP, component C), and keep it in a liquid state using a heat preservation device. Then, TMP was added dropwise to the TDI solution, and the drop was completed in half an hour. Insulated for two hours, NCO was 19.10% (detecting the weight percentage of NCO groups, NCO groups accounted for the total solids mass percentage, that is, removing other components except the solvent, and the detection method of the following embodiments is the same), The obtained TDI / TMP prepolymer (see Table 2). Add 300g of MDI (E-1) to the TDI / TMP prepolymer, mix thoroughly for half an hour, and the NCO is 31.01%, to o...

Embodiment 2

[0034] In a four-necked flask equipped with a thermometer, an electromagnetic stirrer, and a reflux condenser, under the protection of nitrogen, add 45g of TDI (A-1) and 490.93g of dehydrated butyl acetate, keep the temperature in a water bath at 40°C, and stir for 10 minutes to make it evenly mixed , to obtain TDI solution. Heat and melt 11.55g of dehydrated trihydroxypropane, and keep it in a liquid state by using a heat preservation device to keep it warm. Then, TMP was added dropwise to the TDI solution, and the drop was completed in half an hour. After incubation for two hours, the NCO was 19.10%, and the obtained TDI / TMP prepolymer was obtained (see Table 2). Add 300g of MDI (E-1), and mix well under electromagnetic stirring for half an hour, and the NCO is 31.01%. Add 134.38 g of n-pentanol dropwise into the mixture of TDI / TMP / MDI, and keep the temperature at 60° C. for 3 hours. Cool down, stop and discharge. Finally, a clear product with an NCO content of 9.81%, a ...

Embodiment 3

[0036]In a four-neck flask equipped with a thermometer, an electromagnetic stirrer, and a reflux condenser, under the protection of nitrogen, add 45g of TDI (A-1), 619.39g of a 1:1 mixture of dehydrated butyl acetate and ethyl acetate, and keep the water bath for 40 ℃, stirring for 10 min to make it evenly mixed. Heat and melt 11.55g of dehydrated trihydroxypropane, and keep it in a liquid state by using a heat preservation device to keep it warm. Then, TMP was added dropwise to the TDI solution, and the drop was completed in half an hour. After incubation for two hours, the NCO was 19.10%, and the obtained TDI / TMP prepolymer was obtained (see Table 2). Add 350g of MDI (E-2), and mix thoroughly for half an hour under electromagnetic stirring, and the NCO is 31.07%. 212.84 g of n-octanol was added dropwise into the mixture of TDI / TMP / MDI, and the temperature was kept at 60° C. for 3 hours. Cool down, stop and discharge. The finally obtained NCO content is 9.53%, the viscosi...

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Abstract

The invention discloses a preparation method for a low free toluene diisocyanate (TDI) polyurethane pre-polymer curing agent. The preparation method for the low free TDI polyurethane pre-polymer curing agent comprises that a composition A and a composition B are put into a reaction kettle, nitrogen is injected and mixed, a molten composition C is added, and thus TDI/ Trimethoprim (TMP) pre-polymer is obtained through reaction; a composition E is added, heated to 60-80 DEG C and reacted for 30-60 minutes; a composition D is added and reacted for 2-6 hours; and the low free TDI polyurethane pre-polymer curing agent with free TDI content which is lower than 0.4 % is obtained. The composition A is 2,4-TDI or TDI-80, the composition B is solvent with boiling point which is less than or equal to 200 DEG C, the composition C is trimethylolpropane which is dewatered by agent, the composition D is an aliphatic compound which contains 1-3 hydroxyls, and the molecular weight is 60-3000, and the composition E comprises one or a plurality of four kinds of diphenyl methane diisocyanates, namely, E-1, E-2, E-3 and E-4. The pre-polymer curing agent which is prepared by the preparation method for the low free TDI polyurethane pre-polymer curing agent is low in viscosity and good in stability.

Description

technical field [0001] The invention relates to a polyurethane curing agent, in particular to a preparation method of a polyurethane prepolymer curing agent with low free TDI. technical background [0002] Polyurethane coatings have excellent performance and have rapidly become the most important and widely used coating varieties since their birth. Widely used in various painting fields, polyurethane coatings are widely used as automotive coatings, wood coatings, building exterior wall coatings, metal anti-corrosion coatings, aerospace, aviation, ships, tanks and other coatings and invisible coatings. [0003] The paint film of polyurethane coatings has the advantages of high hardness, good toughness, wear resistance, strong chemical resistance, and fast drying. Therefore, polyurethane is developing rapidly in China and is the largest variety of solvent-based coatings. The amount of polyurethane coatings in furniture and decoration has always been relatively large, and it o...

Claims

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Application Information

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IPC IPC(8): C08G18/76C08G18/32C08G18/30C08G18/10C09D7/12
Inventor 黄洪陈卓司徒粤张心亚
Owner SOUTH CHINA UNIV OF TECH
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