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A kind of blocked diphenylmethane diisocyanate curing agent and preparation method thereof

A technology of diphenylmethane and diisocyanate, which is applied in the field of blocked diphenylmethane diisocyanate curing agent, can solve the problems of fast volatilization rate, slow chemical reaction speed, and physical injury of operators, so as to improve product performance, Good stability and fast curing effect

Active Publication Date: 2016-05-11
J&H XIANGYANG CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The closed TDI curing agent and HDI curing agent have the following disadvantages: 1. The toxicity of free monomers. Although they are not released at room temperature after being sealed, -NCO will be unblocked under high temperature baking conditions. At the same time, free TDI and HDI are unblocked. Because of their low boiling point, fast volatilization rate and slow chemical reaction speed, they will diffuse into the air before reacting with hydroxyl groups, causing greater harm to the body of the operator. There is still the problem of free monomers polluting the environment; 2. The unblocking temperature is relatively high. Generally, the unblocking temperature of the closed HDI curing agent is above 140 ° C, and the unblocking temperature of the closed TDI curing agent is above 120 ° C. This not only causes It is a waste of energy, but it cannot be used for heat-sensitive components, electronic components, plastic parts, etc. that require the coating temperature to be below 100 degrees.
Since 4, 4 ， -MDI has high activity, and the two -NCOs have the same activity. In this patent, the NCO-containing component is added dropwise to the OH-containing component. When the dropwise addition reaches the equivalence point, the system will release a lot of heat. The reaction process is difficult to control
[0008] From the above, the current domestic research on closed MDI curing agent is in its infancy, and there is no relatively complete literature report

Method used

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  • A kind of blocked diphenylmethane diisocyanate curing agent and preparation method thereof
  • A kind of blocked diphenylmethane diisocyanate curing agent and preparation method thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0055] Homemade Molecular Weight Regulator A

[0056] In the reaction kettle equipped with condensing reflux, pass N 2 For protection, add 125 grams of MDI-100, 100 grams of ethyl acetate and 112 grams of N,N-dimethylformamide, heat up to 60°C and stir evenly, then cool down to 40°C, add 87 grams of methyl ethyl ketoxime dropwise , Pay attention to controlling the temperature in the kettle to rise slowly. After adding the material, raise the temperature to 60-70°C for 0.5 hours, 70-80°C for 1.5 hours, and discharge the material to obtain a molecular weight regulator A with a solid content of 50%.

[0057] Homemade Molecular Weight Regulator B

[0058] ⅰ. Preparation 4,4 ， -MDI modified product: In the reaction kettle equipped with condensing reflux device, pass N 2 For protection, add 125 grams of MDI-100, 100 grams of ethyl acetate, 124.5 grams of N,N-dimethylformamide, heat up to 60°C and stir evenly, then cool down to 40°C, add 49.5 grams of hydroquinone bis( 2-hydroxye...

Embodiment 2

[0062] Homemade Molecular Weight Regulator A

[0063] In the reaction kettle equipped with condensing reflux, pass N 2 For protection, add 125 grams of MDI-100, 100 grams of ethyl acetate and 71 grams of N,N-dimethylformamide, heat up to 60°C and stir evenly, then cool down to 40°C, add 46 grams of absolute ethanol dropwise, pay attention to control The temperature in the kettle rises slowly. After adding the materials, raise the temperature to 60-70°C for 0.5 hour, 70-80°C for 1 hour, and discharge the material to obtain the molecular weight regulator A with a solid content of 50%.

[0064] Homemade Molecular Weight Regulator B

[0065] ⅰ. Preparation 4,4 ， -MDI modified product: In the reaction kettle equipped with condensing reflux device, pass N 2 For protection, add 75 grams of MDI-100 and 50 grams of MDI-50, 100 grams of ethyl acetate, 98 grams of N,N-dimethylformamide, heat up to 60°C and stir evenly, then cool down to 40°C, and add in five times 29.5 grams of 3-met...

Embodiment 3

[0069] The preparation methods of molecular weight regulator A and molecular weight regulator B are the same as in Example 1.

[0070] Preparation of closed MDI curing agent

[0071] a. In the reaction kettle equipped with condensing reflux device, pass N 2 Protection, add 250 grams of MDI-100, 50 grams of ethyl acetate and 35 grams of N, N-dimethylformamide, stir well and add 110 grams of molecular weight modifier B prepared in Example 1; b, add 44.7 grams in five times Gram 1,2,6-hexanetriol, the feeding time is 1.5 hours, the temperature in the control kettle is below 50°C, after adding the material, slowly heat up to 70-80°C, and react for 2 hours; c, cool down to 45°C, divide Add 92 grams of diethyl malonate and 42 grams of acetone oxime six times, complete the addition in 2 hours, then raise the temperature to 70-80°C and react for 2 hours; d, cool down to 60°C, add 4 grams of ethanol and 6 grams of tert-butanol E, add 11 grams of cyclohexanone, stir evenly, and discha...

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Abstract

The invention relates to a closed diphenyl-methane-diisocyanate curing agent and a preparation method thereof, and the curing agent is generated from MDI, a self made molecular weight regulator, a micromolecular triol, a blocking agent and a stabilizing agent in an organic solvent by reaction. The preparation method comprises two steps: firstly, the molecular weight regulator is prepared by reaction of MDI and the blocking agent; secondly, MDI is prepolymerized with triol under the effect of the self made molecular weight regulator, and then is reacted with the blocking agent for preparing the closed curing agent, and finally the storage stabilizing agent is added. The invention is characterized in that: 1. the deblocking temperature of the closed curing agent is lower than that of the closed TDI curing agent; 2. the NCO percentage content of the curing agent is higher than that of the MDI prepolymer curing agent; 3. the curing agent has good storage stability, and is mainly used as a curing agent ingredient of the high temperature baking type polyurethane paint and the adhesive, and can be prepared to be solvent type and water soluble type closed curing agent.

Description

technical field [0001] The invention relates to a blocked diphenylmethane diisocyanate curing agent, specifically diphenylmethane diisocyanate (MDI), small molecule trihydric alcohol, and isocyanate blocking agent to prepare a blocked diphenylmethane diisocyanate curing agent and its preparation method. Background technique [0002] Blocked polyisocyanate curing agent is one of the main components of polyurethane high-temperature baking varnish. Its main advantage is that it can coexist stably with resin components containing active hydrogen groups (hydroxyl, carboxyl, amine, etc.) for a long time at room temperature, so it can Made into easy-to-use one-component polyurethane baking coatings, available in solvent, water-soluble and powder forms. After the polyurethane high-temperature baking varnish is painted and constructed, at high temperature, the blocking groups latent in the coating can be unblocked, releasing NCO active groups, which chemically react with hydroxyl, c...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08G18/80C08G18/32C08G18/10C09D175/04C09J175/04
CPCC08G18/8019C08G18/8029C09D175/04C09D175/14C09J175/06
Inventor 周函韵周建明何绍群刘加胜傅坚宋亚莉
Owner J&H XIANGYANG CHEM