JPH0368617A - Production of aromatic polyisocyanurate - Google Patents

Abstract

PURPOSE:To prepare an arom. polyisocyanurate giving a coating film excellent in the physical properties when used as a coating material by reacting an arom. polyisocyanate with a specific diol and then trimerizing the resulting urethane compd. in the presence of a catalyst to produce uethane prepolymer. CONSTITUTION:An arom. polyisocyanate (e.g. 2,4-tolylene diisocyanate) is reacted with an aliph. diol having at least two hydrocarbon groups in the molecule (e.g. 2,2,4-trimethylpentane-1,3-diol) to give a urethane compd., which is trimerized in the presence of a catalyst [e.g. N,N',N''-tris(dimethylaminopropyl)- haxahydro-s-triazine] to produce a urethane prepolymer contg. an isocyanurate group.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing an aromatic polyisocyanurate compound.

Aromatic polyisocyanurate compounds have a highly stable chemical structure and are known to be curing agents for polyurethane paints with excellent curability, heat resistance, and weather resistance.

[Conventional technology]

As a method for producing an aromatic polyisocyanurate compound, a method is known in which urethane modification is performed using an aromatic polyisocyanate and a predetermined amount of polyol, and then a trimerization catalyst is added to perform isocyanuration.

For example, JP-A-60-15419 is characterized in that a diol having a number average molecular weight of 60 to 500 is used as a polyol in urethanization in order to prevent the coating film from changing over time when used as a paint.

Furthermore, in JP-A No. 57-2320, a method of using a catalyst was investigated for the purpose of suppressing the cloudiness of the reaction mixture that occurs as the trimerization reaction progresses after urethanization.

[Tia to be Solved by the Invention] In general, aromatic isocyanurate compounds have higher reactivity of the isocyanate they contain and superior drying properties than aliphatic, alicyclic, or aromatic alicyclic isocyanurate compounds. Therefore, in fields where there is a lot of painting work that requires quick drying,
It is being used effectively. However, it has a drawback that the types of polyols used are limited because of poor compatibility with polyols used as main ingredients.

In addition, when used on various parts such as bicycles, architecture, bridges, wood products, and plywood coatings, in addition to the hardness, heat resistance, and weather resistance of urethane paints, the hardness and impact resistance of the coating film A variety of coating film properties are often required, such as , solvent resistance, and stain resistance.

However, none of the conventional aromatic polyisocyanurate compounds can satisfy these physical properties of a coating film, and there has been a desire for an aromatic polyisocyanurate compound that can provide suitable physical properties of a coating film when formed into a paint.

The problem to be solved by the present invention is to improve the compatibility of the aromatic isocyanurate compound with the main ingredient, that is, various polyols, without impairing the quick drying properties of the aromatic isocyanurate compound, thereby improving the coating performance of the aromatic isocyanurate compound. An object of the present invention is to provide a manufacturing method.

[Means to solve the problem]

In view of the above-mentioned problems, the present inventors have made extensive studies to solve these problems, and have found that as a diol, 2
After being urethane-modified with an aliphatic diol having 1lIf substituents of 1 or more hydrocarbons, the nurate-modified aromatic isocyanurate compound not only shows marked improvement in compatibility with various base polyols, but also can be used as a paint. The present inventors have discovered that various physical properties of the coating film are far superior to those of conventional coatings, and have completed the present invention.

That is, the present invention provides a method for producing a urethane prepolymer containing an isocyanurate group by subjecting an aromatic polyisocyanate and a diol to a urethanization reaction and then performing a trimerization reaction in the presence of a catalyst. This is a method for producing aromatic polyisocyanurate, characterized in that the polyisocyanurate is an aliphatic diol having two or more hydrocarbon substituents in one molecule.

The present invention will be specifically explained below.

Aromatic polyisocyanates used in the method of the invention include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,5-naphthalene diisocyanate, 1,4-naphthalene diisocyanate, 1,4-phenylene diisocyanate, 1.3-phenylene diisocyanate, l-methyl-2,5-phenylene diisocyanate, 1-methyl-3,5-phenylene diisocyanate, 1-ethyl-2,4-phenylene diisocyanate, 1-isopropyl-2,4-phenylene diisocyanate , 1,3-dimethyl-4,6-phenylene diisocyanate, 1,4-dimethyl-25-phenylene diisocyanate, 1-chlorobenzene-2,4-diisocyanate, 1-nitrobenzene-2,4-diisocyanate, 2- Nitrobenzene-1,4-diisocyanate, 1-methoxybenzene-2,4-diisocyanate, 1-ethoxybenzene-2,4-diisocyanate,
Biphenyl-2,4°-diisocyanate, 3-3°-
Dimethylbiphenyl-4,4°-diisocyanate, 3
-3'-dimethoxybiphenyl-4,4'-diisocyanate, diphenylmethane-2,2'-diisocyanate, 3-3'-dichlorodiphenylmethane-4,4'-
Diisocyanate, 3,5-dimethyldiphenylmethane-4,4' diisocyanate, diphenyl ether-2
, 4'-diisocyanate, diphenyl ether-4,
4''-diisocyanate and the like.

These may be used alone or in combination of two or more.

Further, the diol used in the urethanization reaction of the present invention may be any aliphatic diol having two or more hydrocarbon substituents in one molecule, and specifically, 2.2-
Diethyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 2-n, butyl-2-
Ethyl-1,3-propanediol, 3-methyl 1.3
-butanediol, 2.2.4-trimethyl-1,3
Examples include diols such as bentanediol, 2-ethyl-1,3,hexanediol, and 2,5-dimethyl-2,5-hexanediol, among which 2-ethyl-1,3-
Hexanediol, 2,2.4-trimethyl-1,3
-bentanediol is preferably used.

The amount of these diols used has an equivalent ratio of NGO/Ql (2 to 100) with respect to the isocyanate group.

The urethanization reaction can be carried out in the presence or absence of an inert solvent, but is usually carried out by dropping the diol component described above into a solution of an aromatic polyisocyanate mixed with an inert solvent while stirring. Ru. Inert solvents used at this time include ethyl acetate, n-butyl acetate,
Examples include isobutyl acetate, acetone, methyl ethyl ketone, henzhen, toluene, xylene, etc., and the amount used is 0.3 to 4 times the weight of the reaction raw material.

The reaction temperature for urethanization is usually 30 to 100°C, preferably 50 to 90°C, and the reaction time is about 1 to 6 hours.

The bilayering reaction of the present invention can be carried out subsequent to the urethanization reaction.

As the trimerization catalyst used in the method of the present invention, any catalyst that is normally used in trimerization reactions can be used, but tertiary amino is particularly preferred, and triethylamine, N, N'-dimethylaniline, etc. , tributylamine, N-ethylpiperazine, N.

Examples include N-dimethylpiperazine, Mannich base of a phenolic compound, N, N', N"-tris(dimethylaminopropyl)-hexahydro-5yh-+-lyazine, etc. Among them, N, N', N"-tris (dimethylaminopropyl)-hexahydro-3yh-
Mannich bases of triazines or phenolic compounds are preferred.

The amount of these trimerization catalysts used is 0.01 to 1.0% by weight based on the aromatic polyisocyanate as a raw material.

The reaction temperature for trimerization is preferably 0 to 30°C, and the reaction time is preferably 4 to 20 hours.

Furthermore, an antioxidant is added as a coloring inhibitor during the Nikei reaction from the start of the reaction. Examples of antioxidants include organic phosphorus compounds and phenolic compounds, and phosphorus antioxidants such as triphenyl phosphite and triethyl phosphite are particularly preferred.The amount of antioxidant used depends on the aromatic polyisocyanate raw material. It is preferably 0.05 to 1.0% by weight.

Examples of the trimerization reaction terminator include #s such as phosphoric acid, sulfuric acid, hydrochloric acid, acetic acid, trifluoroacetic acid, P-)luenesulfonic acid, and benzenesulfonic acid, and acid chlorides such as benzoyl chloride and acetyl chloride. The amount used is preferably 1 to 3 times the equivalent to neutralize the trimerization catalyst used.

In general, the reaction is carried out by charging an aromatic polyisocyanate, a color inhibitor, a diol, and an inert solvent into a reactor in which the reaction system can be sufficiently stirred, and carrying out the urethanization reaction under a nitrogen atmosphere.
Further, a trimerization catalyst is added in portions to allow the reaction to proceed until the NC0% and unreacted diisocyanate reach predetermined values, and at that point, a reaction terminator is added to stop the dimerization reaction.

(Effect of the invention) The aromatic polyisocyanurate compound produced by the above method has good compatibility with various polyols used as a base ingredient, and the paint obtained by these compounds meets the requirements when used as a paint. It has excellent performance, ie, coating film hardness, heat resistance, weather resistance, hardness, impact resistance, solvent resistance, stain resistance, etc., and is of high industrial value.

〔Example〕

Hereinafter, the present invention will be specifically explained with reference to Examples and Comparative Examples.

Example 1 2.4-) lylene diisocyanate (hereinafter referred to as 2.4
After charging 81.0 parts by weight (abbreviated as DI) and 0.1 parts by weight (triphenylphosphite), the inside of the reaction system was made into a nitrogen atmosphere and the temperature of the reaction solution was raised to 60°C. under fi stirring,
The reaction solution was kept at 60°C, and 19.0 parts by weight of 2,2.4-) dimethylpentane-1,3-diol and 1 part of butyl acetate were added.
00 parts by weight was added, the reaction solution was heated to 80°C, stirred at the same temperature for 3 hours to perform a urethane reaction, and further heated to 90°C.
The temperature was raised to 100.degree. C., and the reaction was carried out at the same temperature for 1 hour to complete the urethanization reaction.

After the urethanization reaction, the reaction solution was cooled to 10°C, and NN',
0.02 parts by weight of N"-tris(dimethylaminopropyl)-hexahydro-3yh-triazine was added, and the solution temperature was kept at 10°C and stirred for 7 hours to perform an isocyanurate reaction. Finally, orthorin 80.08 Parts by weight were added to complete the isocyanurate reaction.

Progress of the reaction was confirmed by measuring the decreasing NGO content and unreacted diisocyanate. The NGO content was determined by conventional titration analysis, and the unreacted diisocyanate was determined by gas chromatography. NCO of the product obtained
The content was 8.0% by weight, and the viscosity determined by a Brookfield rotational viscometer was 58 cps/25°C.

Unreacted TDI determined by gas chromatography was 0.47% by weight based on the resin solid content.

Example 2 As in Example 1, 2.4-Ta1l 82.5% by weight,
After collecting 0.1 part by weight of triphenylphosphite,
The inside of the reaction system was made into a nitrogen atmosphere, and the temperature of the reaction solution was raised to 60°C.

While stirring, 17.5 parts by weight of 2,2-diethyl-1,3-propanediol and 100 parts by weight of butyl acetate were added, and the reaction solution was heated to 80°C to perform a urethanization reaction. The temperature was kept at 80°C for 3 hours, and the temperature was further raised to 90°C.
A time reaction was performed.

After the urethanization reaction, the reaction solution was cooled to 10°C and heated with N.

Add 0.02 parts by weight of N',N'-1-lis(dimethylaminopropyl)-hexahydro-5yh-triazine, keep the liquid temperature at 10"C and stir for 8 hours to perform an isocyanurate reaction. Finally, 0.08 parts by weight of orthophosphoric acid was added to complete the reaction.The analysis results are NGO
The content was 17.9% by weight, and the viscosity was 62 cps/25°C.

Unreacted TDI was 0.48% by weight based on the resin solid content.

Example 3 After collecting 81.0 parts by weight of 2.4-TDI and 0.1 parts by weight of triphenyl phosphite in the same manner as in Example 1, the reaction system was made into a nitrogen atmosphere and the reaction solution was heated to 60°C. The temperature rose. While stirring, the reaction solution was kept at 60°C and 2-ethyl-1,3
-Hexanediol 19.0 parts by weight, butyl acetate 100 parts
! 1 part was added, and the temperature of the reaction solution was raised to 80° C., then kept at that temperature for 3 hours, and further stirred at 90″C for 1 hour to carry out the urethanization reaction.

After the urethanization reaction, the reaction solution was cooled to 10°C and heated with N.

Add 0.02 parts by weight of N',N''-tris(dimethylaminopropyl)-hexahydro-5yh-triazine, keep the liquid temperature at 10°C and stir for 7 hours to perform isocyanurate formation, and finally ortholine The reaction was completed by adding 0.08 parts by weight of acid, and the analysis result showed that the NGO content was 7.
．． 9% by weight, viscosity 60cps, unreacted TDI is 0.50f based on resin solid content! It was 1%.

Comparative Example 1 After charging 85.3 parts by weight of 2.4-TDI and 0.1 part by weight of triphenyl phosphite in the same manner as in Example 1, the reaction system was made into a nitrogen atmosphere and the reaction solution was heated to 60°C. The temperature rose.

Press a, keep the reaction liquid temperature at 60°C, add 14.6 parts by weight of diethylene glycol and 100 important parts of butyl acetate,
Thereafter, the temperature of the reaction solution was raised to 80°C, the reaction solution was kept at the same temperature for 3 hours, and further stirred at 90°C for 1 hour to carry out the urethanization reaction.

After the urethanization reaction, the reaction solution was cooled to 100C and heated with N.

Add 0.02 parts by weight of N',N''-tris(dimethylaminopropyl)-hexahydro-5yh-triazine, keep the reaction temperature at 10°C and stir for 3 hours to perform an isocyanurate reaction. Finally, orthophosphoric acid 0.08
Parts by weight were added to complete the reaction. The analysis results are from NGOs.
The content was 8.0% by weight, the viscosity was 63 cps, and the unreacted TDI was 0.60% by weight based on the resin solid content.

Comparative Example 2 After charging 87.3 parts by weight of 2.4-TDI and 0.1 part by weight of triphenyl phosphite in the same manner as in Example 1, the reaction system was made into a nitrogen atmosphere and the reaction solution was heated to 60°C. It was warm. While stirring, the temperature of the reaction solution was maintained at 60°C, and 12.6 parts by weight of 1,3-butanediol and 100 parts by weight of butyl acetate were added.
Thereafter, the temperature of the reaction solution was raised to 80.degree. C., and the reaction solution was kept at 80.degree. C. for 3 hours, and further stirred at 90.degree. C. for 1 hour to carry out a urethanization reaction.

After the urethanization reaction, the reaction solution was cooled to 10°C and heated with N.

If',N'-tris(dimethylaminopropyl)-hexahydro-5yh-triazine was added in an amount of 0.02 parts by weight, kept at 10°C and stirred for 4 hours to perform an isocyanurate reaction, and finally orthophosphoric acid was added. The reaction was completed by adding 0.08 parts by weight, and the analysis result showed that the NGO content was 7.
8% by weight, viscosity 72 cps, and unreacted TDI was 0.63% by weight based on the resin solid content.

Comparative Example 3 After charging 82.2 parts by weight of 2.4-TDI and 0.1 parts by weight of triphenyl phosphite in the same manner as in Example 1, the reaction system was made into a nitrogen atmosphere and the reaction solution was heated to 60°C. The temperature rose,
While stirring, the temperature of the reaction solution was maintained at 60°C, and 17.7 fE parts of dibrobrene gellicol and 100 parts by weight of butyl acetate were added.Then, the reaction solution was heated to 80°C and kept at the same temperature for 3 hours. Then, the temperature was further raised to 90'C and stirred for 1 hour to carry out the urethanization reaction.

After the urethanization reaction, the reaction solution was cooled to lOoC and
, 0.02 parts by weight of N'-tris(dimethylaminopropyl)-hexahydro-5yh-)riazine was added, the liquid temperature was constantly maintained at 10°C, and the mixture was stirred for 4.5 hours to perform an isocyanurate reaction. Finally, 0.08 parts by weight of orthophosphoric acid was added to complete the reaction. The analysis results showed that the NGO content was 7.7% by weight, the viscosity was 73 cps, and the unreacted Ti was 0.64% by weight based on the resin solid content. Ta.

Table 1 shows the compatibility and physical properties of the aromatic isocyanurate compounds obtained in Examples 1 to 3 and Comparative Examples 1 to 3, respectively.
, shown in Table-2 and Table-3.

(Margin below)

Claims (1)

[Claims] 1) In a method for producing a urethane prepolymer containing an isocyanurate group by urethanizing an aromatic polyisocyanate and a diol and then performing a trimerization reaction in the presence of a catalyst, the diol is contained in one molecule. A method for producing an aromatic polyisocyanurate, which is an aliphatic diol having two or more hydrocarbon substituents.