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Low free TDI trimer coating crosslinking agent
2017-7-29 11:37:56
Low free TDI trimer coating crosslinking agent
The modified low-free TDI trimer crosslinking agent with the self-matched catalyst was used, and 50% of the solid dissociation TDI was less than 1.0%, which was the requirement of the national standard.
The choice of catalyst, the dosage of fatty alcohol in the formula and the influence of temperature on the reaction were also discussed. Experimental results show that the use of single catalyst is difficult to meet the synthesis requirements of low free TDI trimer crosslinking agent, fatty alcohol: TDI quality ratio is 3:50, the film performance of crosslinking agent is excellent.
Toluene diisocyanate (TDI) trimer crosslinking agent is one of the important components of PU wood coatings. TDI 3 get together the generated different melamine urea acid ester six-member ring has good thermal stability and chemical stability, its glass transition temperature is higher, crosslinking agent and adduct collocation is used can greatly shorten the work time of paint film, the improvement of paint film burnish and mechanical properties.
Therefore, TDI trimer crosslinking agent is widely used in PU primer and surface paint. At present domestic manufacturer production in line with the national standard of low free TDI trimer most crosslinking agent is using chemical methods, produced by the method of crosslinking agent is free TDI on the high side, high relative molecular mass, strong polarity, and poor compatibility of acrylic resin, quality compared to sa, bayer (imported TDI trimer compared crosslinking agent has certain gap.
In this study, 16-18 carbon long chain fatty alcohols were used to modify TDI trimer, and the relative molecular weight of TDI trimer was moderately reduced and free TDI was reduced. And long chain fatty alcohol belongs to nonpolar structure, and the introduction of long chain fatty alcohol can reduce the polarity of crosslinking agent, thus improving the compatibility with acrylic resin.
Chinese name: Diethyl toluene diamine(DETDA)
Diethyltoluenediamine Raw material ：
TDA industrial, Sichuan production
Ethylene (Et) polymer grade, Shanghai production
TEA industrial imports
The modified low-free TDI trimer crosslinking agent with the self-matched catalyst was used, and 50% of the solid dissociation TDI was less than 1.0%, which was the requirement of the national standard.
The choice of catalyst, the dosage of fatty alcohol in the formula and the influence of temperature on the reaction were also discussed. Experimental results show that the use of single catalyst is difficult to meet the synthesis requirements of low free TDI trimer crosslinking agent, fatty alcohol: TDI quality ratio is 3:50, the film performance of crosslinking agent is excellent.
Toluene diisocyanate (TDI) trimer crosslinking agent is one of the important components of PU wood coatings. TDI 3 get together the generated different melamine urea acid ester six-member ring has good thermal stability and chemical stability, its glass transition temperature is higher, crosslinking agent and adduct collocation is used can greatly shorten the work time of paint film, the improvement of paint film burnish and mechanical properties.
Therefore, TDI trimer crosslinking agent is widely used in PU primer and surface paint. At present domestic manufacturer production in line with the national standard of low free TDI trimer most crosslinking agent is using chemical methods, produced by the method of crosslinking agent is free TDI on the high side, high relative molecular mass, strong polarity, and poor compatibility of acrylic resin, quality compared to sa, bayer (imported TDI trimer compared crosslinking agent has certain gap.
In this study, 16-18 carbon long chain fatty alcohols were used to modify TDI trimer, and the relative molecular weight of TDI trimer was moderately reduced and free TDI was reduced. And long chain fatty alcohol belongs to nonpolar structure, and the introduction of long chain fatty alcohol can reduce the polarity of crosslinking agent, thus improving the compatibility with acrylic resin.
Chinese name: Diethyl toluene diamine(DETDA)
Diethyltoluenediamine Raw material ：
TDA industrial, Sichuan production
Ethylene (Et) polymer grade, Shanghai production
TEA industrial imports
A reagent grade additives
The low free TDI trimer crosslinking agent was used for the experiment of raw materials. TDI: industrial products, 80/20; 16-18 alcohol: industrial grade; Butyl acetate: industrial grade; Antioxidants: industrial grade; Catalyst: self-matching; Termination agent: benzoyl chloride.
The synthesis process of low free trimer crosslinking agent. For TDI, 16-18 alcohol, n-butyl acetate, antioxidant into the flask, four mixing uniform heating to 65 ~ 70 ℃ heat preservation 2.5 h. After the heat preservation and catalyst, controlling temperature in 60 ~ 65 ℃. The content of NCO and free TDI were detected after the catalyst drop was 50%. When the index of detection reached the predetermined value, the reaction of benzoyl chloride was added, and the finished product was cooled by the dilution of butyl acetate.
Film forming performance test. Parallel tests were carried out with a homemade trimer crosslinking agent with POLURENEHR. B.S.
Low free TDI three catalyst selection. It can be used to synthesize low free TDI three polymerization catalysts, which can be summarized as alkali metal salts, carboxylic acid salts, alkyl phosphorus and tertiary amine compounds. As a catalyst for TDI trimer, lithium acetate, tri-n-butyl phosphorus, etc. The effect is good, but as a catalyst for the synthesis of low free TDI trimer, the catalytic effect of single type catalyst is not ideal.
A more ideal catalytic effect was obtained by using the recombination of a tertiary amine and alkyl phosphors. It should be pointed out that: lithium acetate insoluble in TDI, solid lithium acetate in after the completion of the reaction is still exist in solid state in the finished products, filter easily blocked when packing bag, increase the production cost and Labour intensity. It is seldom used in actual production to use lithium acetate as catalyst.
Determination of the dosage of modified fatty alcohol. TDI - tri-generation isocyanurate is an ideal result, and it is inevitable to produce TDI in the actual synthesis. The large molecular structure produced by TDI can make the film flexible and easy to crack under low temperature, which is incompatible with acrylic resin. TDI three polymerization of fatty alcohols is a good solution to this problem. There was no significant difference in the use of these two mixtures. The use of fatty alcohol should be determined according to the specific requirements of the formula.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
The low free TDI trimer crosslinking agent was used for the experiment of raw materials. TDI: industrial products, 80/20; 16-18 alcohol: industrial grade; Butyl acetate: industrial grade; Antioxidants: industrial grade; Catalyst: self-matching; Termination agent: benzoyl chloride.
The synthesis process of low free trimer crosslinking agent. For TDI, 16-18 alcohol, n-butyl acetate, antioxidant into the flask, four mixing uniform heating to 65 ~ 70 ℃ heat preservation 2.5 h. After the heat preservation and catalyst, controlling temperature in 60 ~ 65 ℃. The content of NCO and free TDI were detected after the catalyst drop was 50%. When the index of detection reached the predetermined value, the reaction of benzoyl chloride was added, and the finished product was cooled by the dilution of butyl acetate.
Film forming performance test. Parallel tests were carried out with a homemade trimer crosslinking agent with POLURENEHR. B.S.
Low free TDI three catalyst selection. It can be used to synthesize low free TDI three polymerization catalysts, which can be summarized as alkali metal salts, carboxylic acid salts, alkyl phosphorus and tertiary amine compounds. As a catalyst for TDI trimer, lithium acetate, tri-n-butyl phosphorus, etc. The effect is good, but as a catalyst for the synthesis of low free TDI trimer, the catalytic effect of single type catalyst is not ideal.
A more ideal catalytic effect was obtained by using the recombination of a tertiary amine and alkyl phosphors. It should be pointed out that: lithium acetate insoluble in TDI, solid lithium acetate in after the completion of the reaction is still exist in solid state in the finished products, filter easily blocked when packing bag, increase the production cost and Labour intensity. It is seldom used in actual production to use lithium acetate as catalyst.
Determination of the dosage of modified fatty alcohol. TDI - tri-generation isocyanurate is an ideal result, and it is inevitable to produce TDI in the actual synthesis. The large molecular structure produced by TDI can make the film flexible and easy to crack under low temperature, which is incompatible with acrylic resin. TDI three polymerization of fatty alcohols is a good solution to this problem. There was no significant difference in the use of these two mixtures. The use of fatty alcohol should be determined according to the specific requirements of the formula.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
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