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Method for preparing low-free curing agent with solid content of 75% by synthesis of 65/35 toluene diisocynate (TDI)

A technology of toluene diisocyanate and curing agent, which is applied in the field of preparation of low free TDI curing agent, and can solve the problems of too many raw materials and too long process

Inactive Publication Date: 2013-05-08
甘肃银光聚银化工有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] The purpose of the present invention is a new technical solution proposed to solve the defects of too long process and too many raw materials in the above-mentioned technical solution

Method used

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  • Method for preparing low-free curing agent with solid content of 75% by synthesis of 65/35 toluene diisocynate (TDI)
  • Method for preparing low-free curing agent with solid content of 75% by synthesis of 65/35 toluene diisocynate (TDI)
  • Method for preparing low-free curing agent with solid content of 75% by synthesis of 65/35 toluene diisocynate (TDI)

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0043] (1) First add 70kg of solvent butyl acetate, then add 400kg of 65 / 35 toluene diisocyanate (T-65) to mix, and heat to 50°C;

[0044] (2) Add 0.3kg of antioxidant 2,6-di-tert-butyl-p-cresol (BHT) and ultraviolet absorber 2-(2'-hydroxyl-3'5'-di-tert-butyl)-5-chloro - Benzotriazole 0.2kg, the above mixture is warmed up to 60°C;

[0045] (3) Divide 103kg of trimethylolpropane (TMP) into four parts, add 20kg of the first batch of TMP and mix and heat up to 62°C;

[0046] (4) After adding the second batch of TMP23kg and mixing, the temperature was raised to 65°C;

[0047] (5) Add the third batch of TMP27kg and mix and raise the temperature to 68°C;

[0048] (6) Add the fourth batch of TMP33kg and mix and raise the temperature to 70°C;

[0049] (7) After the temperature rise finishes, keep warm for half an hour, add catalyst 2,4,6-tris(dimethylaminomethylphenol) (DMP) 0.24kg, keep warm for 2-3 hours;

[0050] (8) When the viscosity and NCO% reach the requirements, the react...

Embodiment 2

[0053] (1) First add 80kg of solvent ethyl acetate, then add 400kg of 65 / 35 toluene diisocyanate (T-65) for mixing, and heat to 50°C;

[0054] (2) Add 0.3kg of antioxidant 2,6-di-tert-butyl-p-cresol (BHT) and ultraviolet absorber 2-(2'-hydroxyl-3'5'-di-tert-butyl)-5-chloro - Benzotriazole 0.2kg, the above mixture is warmed up to 60°C;

[0055] (3) Divide 103kg of trimethylolpropane (TMP) into four parts, first add the first batch of TMP20kg and mix and then heat up to 65°C;

[0056] (4) After adding the second batch of TMP23kg and mixing, the temperature was raised to 68°C;

[0057] (5) Add the third batch of TMP27kg and mix and then heat up to 70°C;

[0058] (6) Add the fourth batch of TMP33kg and mix and then heat up to 75°C;

[0059] (7) depending on the change in viscosity, add 50kg of solvent remaining ethyl acetate;

[0060] (8) After the temperature rise finishes, keep warm for half an hour, add catalyst 2,4,6-tris(dimethylaminomethylphenol) (DMP) 0.24kg, keep warm ...

Embodiment 3

[0063] Differences: 1. The chromaticity of the step-by-step feeding product is low, which is better than that of the traditional dripping process; 2. The viscosity of the feeding from less to more is low, which is conducive to the stable control of temperature, and the controllability of the reaction process is relatively high. Well, less by-products.

[0064] (1) Heat 1200kg of 65 / 35 toluene diisocyanate (T-65) to 50°C;

[0065] (2) Add antioxidant 2,6-di-tert-butyl-p-cresol (BHT) 0.9kg, ultraviolet absorber 2-(2'-hydroxyl-3'5'-di-tert-butyl)-5-chloro - Benzotriazole 0.6kg, the above-mentioned mixture is warmed up to 60 ℃;

[0066] (3) Divide 309kg of trimethylolpropane (TMP) into four parts, first add the first batch of TMP45kg and mix and then heat up to 65°C;

[0067] (4) Add the second batch of TMP55kg and mix;

[0068] (5) Add the third batch of TMP85kg and mix and then heat up to 68°C;

[0069] (6) Add the fourth batch of TMP124kg and mix and then heat up to 70°C; ...

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Abstract

The invention relates to a method for preparing a low-free curing agent with the solid content of 75% by synthesis of 65 / 35 toluene diisocynate (TDI). The method is characterized by comprising the following steps of: (1) reacting the TDI with trimethylolpropane (TMP) in a reaction solvent at 70+ / -5 DEG C to obtain a prepolymer; (2) adding 2,4,6-tris(dimethylaminomethyl)phenol, namely a trimerization catalyst, to the prepolymer when the weight percentage of a free NCO group is detected to be 15%-16%, and adding phosphoric acid, namely a trimerization inhibitor, to the prepolymer for stopping reaction when the weight percentage of the free NCO group is reduced to 14%-15%; and (3) after 2, 6-butylated hydroxytoluene, namely an antioxidant, is added, diluting a prepolymer by a general solvent for polyisocyanates to discharge when a prepolymer curing agent is changed into transparent liquid, when the complete reaction is finished within 2.5h-4h. The obtained environmental-friendly coating curing agent with low-free TDI and high solid content has the excellent characteristics of high gloss of a coating film as well as high elasticity and toughness, and greatly reduces toxicity and transportation costs.

Description

technical field [0001] The invention relates to a method for preparing a curing agent in aromatic polyurethane coatings, in particular to a method for preparing a curing agent with 75% solid content and low free TDI by using 65 / 35 toluene diisocyanate. Background technique [0002] Curing agent is an important part of two-component polyurethane coatings. The types of curing agent can be divided into N-75 (75%), N-60, and N-50 according to the solid content. The higher the solid content, the better the curing agent. The smaller the environmental hazard, the lower the transportation cost of the product, and the more difficult the preparation process and processing are. As a TDI polymer with special properties, the curing agent is widely used in polyester paints, high-grade acrylic paints, and polyurethane adhesives. It has excellent properties such as ultra-fast curing, heat resistance, UV resistance, yellowing resistance, and low free TDI content properties, especially its l...

Claims

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Application Information

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IPC IPC(8): C07D251/34C09D7/12
Inventor 周玲李晓明强光明付振波陈玫君蒙鸿飞陶春霞
Owner 甘肃银光聚银化工有限公司
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