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Curing agent 4,2'- and 4,4'-methyl diphenylene diisocyanate prepolymer and preparation thereof

A technology of diphenylmethane and diisocyanate, applied in 4 fields, can solve the problems of inability to obtain products with high solid content, single variety of prepolymers, high product viscosity, etc. Effects with low strength and toxicity

Inactive Publication Date: 2009-05-27
周建明
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantages are: the proportion range of 4,2'-MDI and 4,4'-MDI is narrow, the variety of prepolymers is single, the product viscosity is relatively high, and products with high solid content cannot be produced, and of course it cannot meet the requirements of polyurethane Wide range of needs for curing agent strength, viscosity, and room temperature curing speed for various uses in the industry

Method used

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  • Curing agent 4,2'- and 4,4'-methyl diphenylene diisocyanate prepolymer and preparation thereof
  • Curing agent 4,2'- and 4,4'-methyl diphenylene diisocyanate prepolymer and preparation thereof
  • Curing agent 4,2'- and 4,4'-methyl diphenylene diisocyanate prepolymer and preparation thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0047] a. Add 100 grams of molten 4,4'-MDI and 60 grams of ethyl acetate in the reaction kettle, stir evenly, heat up to 80°C, add 80 grams of polycarbonate-caprolactone diol dehydrated by vacuum, React at 80-90°C for 2 hours, and at 90-100°C for 1 hour; b, add 150 grams of MDI-45 under stirring (that is, the weight of 4,2'-MDI is 45%, and the weight of 4,4'-MDI 55% mixture), after mixing evenly, lower the temperature to below 80°C, add dropwise a mixture of 37.3 grams of trimethylolpropane and 37.3 grams of ethyl acetate, drop it in 2 hours, and keep it warm at 75-85°C 3 hours, rise to 80~90 ℃ of insulation reaction for 2 hours again, lower the temperature; c, add 25 grams of propylene glycol monomethyl ether acetate solvents according to the solid content requirement of product, stir well, and the solid content of 489 grams of discharging is 75% and the viscosity is 2500mpa.s (25°C) 4,2'- and 4,4'-MDI prepolymer curing agent, the NCO content of the curing agent is 8.6% (11.4...

Embodiment 2

[0052] a. Add 300 grams of molten 4,4'-MDI and 50 grams of ethyl acetate into the reaction kettle, stir evenly, heat up to 70°C, and add 21 grams of 3-methyl-1,5-pentanedi that has been vacuum-dehydrated Alcohol, react at 70-80°C for 2 hours, and react at 90-100°C for 1 hour; b, add 43 grams of MDI-50 under stirring (that is, 4,2'-MDI weight is 50%, 4,4'- MDI weight is 50% mixture), after mixing evenly, cool down to below 80°C, add dropwise the mixed solution of 46 grams of trimethylolpropane and 56 grams of ethyl acetate, drop it in 1 hour, at 70~80°C, Heat preservation reaction for 2 hours, then rise to 80~90°C for heat preservation reaction for 2 hours, and then cool down; c, add 30 grams of xylene solvent according to the solid content of the product, stir evenly, and discharge 546 grams of 4,2 with a solid content of 75%. As for the '- and 4,4'-MDI prepolymer curing agent, the NCO content of the curing agent was detected to be 10.5% (14.1% based on total solids).

Embodiment 3

[0054] a. Add 150 grams of molten 4,4'-MDI and 180 grams of ethyl acetate in the reaction kettle, stir evenly, heat up to 75 ° C, add 200 grams of hydrogenated hydroxyl-terminated polybutadiene diol through vacuum dehydration, React at 75-85°C for 2.5 hours, and react at 90-100°C for 0.5 hours; b, add 200 grams of MDI-60 under stirring (that is, 4,2'-MDI weight is 60%, 4,4'- MDI weight is the mixture of 40%), after mixing evenly, cool down to below 80°C, add dropwise the mixed solution of 53.6 grams of trimethylolpropane and 73.6 grams of ethyl acetate, drop it in 2.5 hours, at 70~80°C, Heat preservation reaction for 1.5 hours, then rise to 80-90°C heat preservation reaction for 3 hours, then lower the temperature; c, add 150 grams of toluene, 180 grams of cyclohexanone, 20 grams of N, N-dimethylformamide solvent according to the solid content of the product, Stir evenly, and discharge 1207 grams of 4,2'- and 4,4'-MDI prepolymer curing agent with a solid content of 50%. The NC...

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Abstract

The invention provides a prepolymer of 4,2'-methyl diphenylene diisocyanate (MDI) and 4,4'- methyl diphenylene diisocyanate (MDI) as a curing agent, and a preparation method thereof. The method comprises the following steps: 4,4-MDI and organic solvent are added to a reaction kettle, heated to between 50 an d 90 DEG C and added with dehydrated polyol, and then react for 2 to 4 hours so as to prepare 4,4-MDI modifier; a mixture of 4,2'-MDI and 4,4'MDI is added and then cooled; and trimethylolpropane and the organic solvent are dripped and thermally insulated, and react for 1 to 6 hours, so as to obtain a product. The method modifies the 4,4-MDI and then blends the 4,4-MDI with the mixture of 4,2'-MDI and 4,4'-MDI and TMP for pre-polymerization, thereby solving the problem of manufacturing the prepolymer with two isomers of MDI in an arbitrary proportioning form. A series of produced prepolymers can meet different requirements of coatings and adhesives in the polyurethane industry on the curing agent, and have the advantages of wide application range, high strength, low toxicity, adjustable room-temperature curing speed, good storage stability, capability of obtaining the products with high solid content, and the like.

Description

technical field [0001] The invention relates to a polyurethane coating, an adhesive curing agent prepolymer and a preparation method thereof, in particular to a 4,2'- and 4,4'-diphenylmethane diisocyanate prepolymer and a preparation method thereof. Background technique [0002] At present, the most commonly used production method of polyurethane curing agent at home and abroad is to use trimethylolpropane (TMP) and toluene diisocyanate (TDI) to react to make TDI prepolymer. Its chemical reaction formula is as follows: [0003] [0004] The prepolymer has unreacted TDI monomer residues in the production process. Due to its high gas phase toxicity, it affects the health of production workers and pollutes the environment. Expensive equipment is required to remove free TDI, and the process It is more complicated. The corresponding domestic products have not undergone cleaning process, and the free TDI content is greater than 2%, which is much higher than the 0.5% standard s...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G18/10
Inventor 周建明何绍群
Owner 周建明
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