JPH0832759B2 - Method for producing modified aromatic polyisocyanate having liquid and stable isocyanurate ring - Google Patents

Description

TECHNICAL FIELD The present invention relates to a modified aromatic polyisocyanate having an isocyanurate ring. More specifically, it relates to the production of a modified aromatic polyisocyanate having a liquid and stable isocyanurate ring, which is easy to produce and has excellent compatibility with other resins.

2. Description of the Related Art Aromatic polyisocyanates are used in various applications such as foams, elastomers, paints and adhesives by reacting with various active hydrogen compounds.

Such an aromatic polyisocyanate can be used by transforming it into a polyisocyanate compound having an isocyanurate ring.

The product obtained by reacting this polyisocyanate compound with an active hydrogen compound has the properties of isocyanurate such as heat resistance, flame retardancy, rigidity, and toughness, and requires such performance. It is used in various fields.

Therefore, many isocyanurate polymerization processes have been carried out for the isocyanurate formation of aromatic polyisocyanates. For example, JP-A-54-32490 and JP-A-52-69497
Each of the publications describes a method for producing a metal salt of acetylacetone, an alkali metal salt of an organic acid, or the like with a catalyst, and these production methods have very high catalyst selectivity with respect to aromatic polyisocyanate. Aromatic polyisocyanates that are small and have a small difference in reactivity between the primary isocyanate group and the secondary isocyanate group, such as diphenylmethane diisocyanate, are easily polymerized in the isocyanurate-forming polymerization reaction, resulting in high viscosity and partial imbalance. It is not preferable because a uniform product having a low isocyanate content and a low compatibility with other resins can be obtained. Also,
If the catalyst is inactivated to increase the stability and the reaction is performed in the absence of a solvent, it has a drawback that an insoluble precipitate is likely to be formed, and the reaction control of isocyanurate formation is difficult. However, it was not completely satisfactory, and there was a demand for its improvement.

DISCLOSURE OF INVENTION Problem to be Solved by the Invention Isocyanurate-modified aromatic polyisocyanate having an isocyanurate ring, which is easy to undergo an isocyanurate-forming reaction of an aromatic polyisocyanate, has storage stability, and has excellent compatibility with other resins. The body was desired. The inventors of the present invention have conducted extensive studies and conducted research on a method for efficiently producing a modified aromatic polyisocyanate containing an isocyanurate ring by adding a trimerization catalyst and specific additives to the aromatic polyisocyanate. The present invention has been found out.

Means for Solving the Problems That is, the present invention is: 1. Aromatic polyisocyanate and / or partially urethanated aromatic polyisocyanate, a trimerization catalyst, an organic phosphite ester and a surfactant are added, and all isocyanate groups are added. 20% by weight or less of isocyanurate is added, and a terminating agent is added if necessary, is a method for producing a modified aromatic polyisocyanate having an isocyanurate ring.

Examples of the aromatic polyisocyanate used in the present invention include, for example, 2,4 or 4,4'-diisocyanate diphenyl ether, 2,4 or 2,6-toluene diisocyanate, 4,6-dimethyl-1,3- Phenylene diisocyanate, 4,4'-diisocyanate dibenzyl, 9,10
-Anthracene diisocyanate, 3,3'-dimethyl-
4,4'-diisocyanate diphenylmethane, 2,6'-dimethyl-4,4'-diisocyanate diphenyl, xylylene diisocyanate, 2,4 or 4,4'-diphenylmethane diisocyanate and the like can be mentioned.

Further, as the aromatic polyisocyanate particularly useful in the present invention, However, n = 0 to 8 includes polymethylene polyfell polyisocyanate represented by the general formula (1) and a mixture containing these.

Further, the partially urethanized aromatic polyisocyanate used in the present invention is a product obtained by urethanization reaction of an aromatic polyisocyanate and a hydroxyl group-containing compound, and a hydroxyl group is added to the aromatic polyisocyanate by a commonly used method. The compound contained is added and the reaction temperature is 10
It can be obtained by carrying out the reaction at 0 ° C or lower, preferably at 60 to 90 ° C for about 2 hours. In this case, when the temperature exceeds 100 ° C., a side reaction occurs, so that the viscosity of the product after the trimerization reaction becomes remarkably high, and in some cases, a gelled product is produced. In this way, by introducing the urethane group, the urethane group exerts a co-catalyst effect, so that the isocyanurate-forming reaction easily proceeds. It is considered that this is because the hydrogen bond is formed between the active hydrogen in the urethane group and the oxygen atom in the isocyanate group, so that the isocyanate group is significantly activated. Therefore, the amount of catalyst added can be reduced by the co-catalyst effect of this urethane group. Also, the increase in the concentration of urethane groups is
Since it lowers the thermal stability that is characteristic of the isocyanurate ring formed thereafter, it is necessary to adjust the urethane group concentration depending on the application. In the present invention, the urethanization rate is preferably 10% by weight or less based on all isocyanate groups.

The urethane-containing hydroxyl group-containing compound used in the present invention has a molecular weight of 2000 or less and a functional group number of 3 or less.

For example, the general formula R'OH, wherein R'is represented by an alkyl group, an allylalkyl group, an alkylaryl group, an aryl group or an alkenyl group.
Examples of the polyhydric alcohol include 2-ethylhexyl alcohol, lauryl alcohol and nonyl alcohol. Also, ethylene glycol, 1,3-butanediol, 1,4-butanediol, propylene glycol, dipropylene glycol, neopentyl glycol, 1,6
-Hexane glycol, 2-ethylhexanediol,
Examples thereof include dihydric alcohols such as 2,2,4-trimethylpentanediol, trihydric alcohols such as trimethylolpropane and glycerin, polyesters and polyether polyols. These can be used alone or as a mixture of two or more kinds. The urethanization reaction and the isocyanurate reaction can be carried out in the absence of a solvent.

The catalyst used for the isocyanurate modification of the present invention includes an alkali metal salt of a carboxylic acid having 2 to 12 carbon atoms,
Phenolates such as potassium phenolate and sodium methoxide, alcoholates, and more particularly effective ones
2,4,6-tris (dimethylaminomethyl) phenol,
2,4-bis (dimethylaminomethyl) phenol, 2,6-
Examples thereof include amine systems such as ditertiary-butyl-4-dimethylaminotrimethylsilanephenol, triethylamine, N, N ', N "-tris (dimethylaminopropyl) hexahydrotriazine, and diazabicycloundecene. Examples of the organic phosphite ester used as are organic phosphite diester and organic phosphite triester.

These compounds are in the molecule Or (However, one hand of an oxygen atom is bonded to a carbon atom), which has 1 to 4 partial structures. In the present invention, for example, as the organic phosphite diester, (RO
₂ P (O) H [wherein R may be the same or different and represents alkyl having 1 to 20 carbons or aryl optionally substituted by alkyl having 1 to 20 carbons (as aryl, for example, phenyl) ] The compound shown by these can be mentioned, and such diesters include, for example, dilauryl hydrogen phosphite, diphenyl hydrogen phosphite, and the like. The alkyl represented by the symbol R may be partially substituted with halogen, such as chloro, such as tris (2,3-dichloropropyl) phosphite. In addition, the oxygen atom of the phosphite may be substituted with a sulfur atom, and examples thereof include trilauryltrithiophosphite.

In addition, for example, (R—O ₃ P [wherein R may be the same or different, alkyl having 1 to 20 carbons or aryl optionally substituted with alkyl having 1 to 20 carbons (aryl is, for example, phenyl And a compound represented by the formula :) such as triethylphosphite, tributylphosphite, tris (2-ethylhexyl) phosphite, tridecylphosphite, trilaurylphosphite, tris (tridecyl).
There are monophosphites such as phosphite, tristearyl phosphite, triphenyl phosphite, tris (nonylphenyl) phosphite and tris (2,4-di-t-butylphenyl) phosphite.

Further, for example, distearyl pentaerythrityl diphosphite, ditridecyl pentaerythritol diphosphite, dinonylphenyl pentaerythritol diphosphite, tetraphenyl tetratridecyl pentaerythrityl tetraphosphite, tetraphenyl dipropylene glycol diphosphite, di derived from a polyhydric alcohol such as tripentaerythritol tri phosphite, tri or tetra-phosphites and as dialkyl (C ₁ ~ ₂₀₎ bisphenol a diphosphite, 4,
Diphosphites derived from bisphenol compounds such as 4'-butylidene-bis (3-methyl-6-6-butylphenyl-di-tridecyl) phosphite, hydrogenated bisphenol A phosphite polymer (molecular weight 2400-
3000) and other polyphosphites.

In the method of the present invention, such a co-catalyst is used in combination with the catalyst, and the amount of the catalyst used may be smaller than the most effective amount when used alone.

The amount of the catalyst used depends on the activity of the catalyst and may be 0.005 to 0.5% by weight based on the starting isocyanate compound. The amount of phosphite used as a cocatalyst is about 1/10 to 20 times that of the catalyst.

In addition, the isocyanurate formation reaction rate is strongly influenced by the initial concentration dependence of the catalyst. Particularly in the case of diphenylmethane diisocyanate, in the case of the isocyanurate formation reaction by the usual method, the gelled substance may be suspended inhomogeneously or, in some cases, It will gel.

Therefore, in order to reduce the dependence of the catalyst on the initial concentration, it is preferable to adopt a method of adding the catalyst at a low initial concentration with a diluent or the like. As the diluent, a compound that is inactive or incombustible with isocyanate is preferable in order to maintain the flame retardancy and heat resistance of the produced polymer. Examples thereof include methylene chloride, trichlorofluoromethane, dichlorodifluoromethane, dichlorotetrafluoroethane, trichlorotrifluoroethane and the like.

By using such a catalyst, a liquid and stable polymer can be obtained by adjusting the partial polymerization to 20% by weight or less of the total isocyanate groups. When the aromatic polyisocyanate is isocyanurate-modified, the compatibility between the isocyanurate-modified product and the aromatic polyisocyanate is not good, and therefore a method of improving the compatibility by introducing a urethane group is used. In the method of the present invention, isocyanurate modification can be achieved in the absence of solvent in any of aromatic polyisocyanates and partially urethanized aromatic polyisocyanates by using a surfactant, and there is no turbidity, high molecular weight polymer. A liquid stable isocyanurate-modified product with less generation of is obtained.
In addition, the isocyanurate modified product produced by using the surfactant has improved compatibility with other resins, and therefore the curing reaction with the compound containing active hydrogen that reacts with the isocyanate group could proceed smoothly. The physical properties of the cured product are also improved.

In the present invention, the surfactant may be added either at the early stage of the reaction or at the late stage of the reaction.

Surfactants used in the present invention include, for example, alkylene oxides such as ethylene oxide, propylene oxide and butylene oxide, preferably ethylene oxide,
It can be obtained by condensing a polyglycol ether obtained by reacting polyethylene glycol or polypropylene glycol with an organic compound containing one reactive hydrogen atom. Such compounds containing one reactive hydrogen atom include alcohols, phenols, thiols, primary and secondary amines. There are also nonionic surfactants consisting of polyglycol ethers and carboxylic acids and sulphonic acids and their amides. These include polyethylene glycol ethers. There is also a surfactant which is a polyalkylene oxide derivative of a phenolic compound containing the polyglycol ether and, for example, one or more alkyl substituents. These include polyethylene glycol nonyl phenyl ether.

Further, examples of the surfactant include those referred to as Pluronic type. These are generally butylene oxide, amylene oxide, phenylethylene oxide,
Cyclohexene oxide, propylene oxide or mixtures thereof are used, for example by polymerizing 1,2-alkylene oxide or substituted alkylene oxide in the presence of an alkali catalyst to produce the corresponding water-insoluble polyalkylene glycol, then , Nonionic surfactants obtained by condensation with the required number of moles of ethylene oxide. These include Prolonic L-61 and Prolonic L-62 (Asahi Denka). Further as a surfactant, for example, an aldehyde produced by a catalytic reaction of a polyolefin such as tripropylene, tetrapropylene, pentapropylene, diisobutylene, triisobutylene, tetrabutylene, propylene-isobutylene and tributene with carbon monoxide and hydrogen. There is a nonionic surface active agent obtained by reacting an alcohol obtained by reducing OH with a necessary number of moles of ethylene oxide. These include polyoxyethylene alkyl ethers, polyoxyethylene lauryl ethers, polyoxyethylene oleyl ethers, and the like.

Further, the surfactants particularly effective in the present invention include those represented by the general formula (2).

Where R, R ', R "are alkyl groups and have 1 carbon atom
20 to 20 pieces.

p, q, and r are integer values of at least 1 and n is 2 to 4
And z is an integer value of 5 or more. These include L
-5340 (U.CC product), Toray Silicon SH193 (Toray product), B8404 (Goldschmitt product) and other silicone-based surfactants. The amount of such a surfactant used is 0.1 to 2 with respect to the amount of aromatic polyisocyanate.
% By weight.

In the isocyanurate-forming modification reaction in the present invention, the reaction temperature is 100 ° C or lower, preferably 15 ° C to 70 ° C. In the reaction, by using a surfactant, the isocyanurate-forming reaction effectively proceeds at a relatively low temperature, and the resulting isocyanurate-modified product is also uniformly dispersed in the reaction product. A stable and liquid isocyanurate modified product is obtained which gradually progresses.

If the amount of the catalyst is large or the reaction temperature is 100 ° C. or higher, a polymer of an isocyanurate compound or a polymer of an allophanate compound is likely to be formed, so that the compatibility may decrease or gelation may occur.

Reaction time of aromatic polyisocyanate modified product, yield,
The quality and the like can be effectively controlled and adjusted depending on the type of catalyst and the amount thereof used. Therefore, the NCO content and viscosity of the modified aromatic polyisocyanate can be arbitrarily adjusted by the NCO content at the time of stopping the reaction, since it can be measured by a commonly known titration analysis.

As described above, the isocyanurate formation according to the present invention has an advantage that the amount of the catalyst is small and the reaction can be performed at a low temperature in a short time.

In producing the isocyanurate-forming aromatic polyisocyanate of the present invention, an acidic compound is used as a terminating agent, if necessary. For example, hydrochloric acid, phosphoric acid, dimethyl phosphate, trimethyl phosphate, triethyl phosphate, tricresyl phosphate, triphenyl phosphate, tributyl phosphate P-toluene sulfonic acid, methyl P-toluene sulfonate, xylene sulfonic acid, benzene sulfone. Examples thereof include acid, methanesulfonic acid, alkylbenzenesulfonic acid, dinaphthalenedisulfonic acid, dinaphthalenemonosulfonic acid, dinonylnaphthalenedisulfonic acid, dinonylnaphthalenemonosulfonic acid, benzoyl chloride, acetyl chloride and the like, and similar compounds.

The terminator is used in an amount of 0.3 to 5 times the equivalent amount, preferably 1.0 to 2.0 times the equivalent amount, based on the amount of the catalyst. By adding it during the isocyanurate-forming reaction, it is possible to promote the stabilization of the modified aromatic polyisocyanate without the reaction solution becoming turbid.

Since this modified product is solvent-free and has stable quality, it is widely used not only as a raw material for plastic foams and elastomers, but also for paints, adhesives, etc., and can be obtained by reaction with active hydrogen compounds. The product exhibits excellent performance in flame retardancy, heat resistance, water resistance, toughness and the like.

Next, the present invention will be described in more detail with reference to Examples.
The present invention is not limited to these.

In the examples, all "parts" and "%" are "parts by weight" and "% by weight" unless otherwise specified.

Example 1 In a one-volume sliding glass four-necked flask equipped with a thermometer, a stirrer, and a nitrogen seal tube, 500 parts of MR-200 as an aromatic polyisocyanate and 4.0 parts of L-5340 as a surfactant were used.
Parts, 1.0 part of ancamine K-54 as a catalyst, 5.0 parts of triethylphosphite as a cocatalyst, R-113 as a diluent.
2.0 parts, the catalyst was charged after mixing with a diluent, the air in the flask was replaced with nitrogen, heated to 50 ° C. with stirring, and
The NCO content measured after the reaction for 2 hours was 28.6%, and the reaction solution was a brown transparent liquid. 0.5 part of phosphoric acid was added to this reaction solution as a terminating agent, and the reaction was terminated after stirring at 50 ° C. for 1 hour.

The isocyanurate-modified polyisocyanate obtained is a brown transparent liquid with an NCO content of 28.6% and a viscosity of 850 cP / 2.
At 5 ° C, the trimer was recognized by infrared absorption spectrum.
No abnormalities were observed even after 6 months.

Examples 2 to 8 The reaction was carried out in the same manner as in Example 1 under the conditions shown in Table 1.
The results are shown in Table 1 and Table 1-1.

Example 9 In the same four-necked flask as in Example 1, 500 MR-200 was used.
Parts, 6.1 parts of 1,3-butanediol as a polyol were charged, the air in the flask was replaced with nitrogen, and the reaction was carried out at 60 ° C. for 2 hours. The NCO content was measured and found to be 29.4%.

Next, 4.0 parts of L-5340, 0.7 parts of ancamine K-54 and 2.0 parts of R-113 were mixed and added, 3.0 parts of triethylphosphite was charged, and the reaction was carried out at 50 ° C. for 2.0 hours. Was measured to be 26.9%. Phosphoric acid (0.35 parts) was added to the reaction solution, and the reaction was stirred at 50 ° C. for 1.0 hour.

The obtained modified isocyanurate was a brown transparent liquid, had an NCO content of 26.9%, a viscosity of 4500 cP / 25 ° C, and a trimer was recognized by an infrared absorption spectrum. No abnormalities in storage stability were observed even after 6 months.

Examples 10 to 17 The reaction was carried out in the same manner as in Example 9 under the conditions shown in Table 1.
The results are shown in Table 1 and Table 1-1.

Comparative Examples 1 to 3 Comparative Example 1 was performed in the same manner as in Example 9. Comparative Examples 2 and 3
Is carried out in the same manner as in Example 1. Charge amount, reaction conditions,
The results and the like are shown in Table 1 and Table 1-1.

Effects of the Invention According to the method of the present invention, it is possible to easily and stably obtain a modified isocyanurate with a small amount of a catalyst for a short time.

Further, the modified product obtained by the method of the present invention is a polyisocyanate modified product which is stable in a liquid state, has good compatibility with other resins, and has a strongly active isocyanate group at the terminal. By reacting these isocyanate groups with a compound having active hydrogen that reacts, a product having good workability, flame retardancy, heat resistance, and rigidity can be obtained.

Claims (2)

[Claims] 1. An aromatic polyisocyanate and / or a partially urethanized aromatic polyisocyanate, to which a trimerization catalyst, an organic phosphite ester and a surfactant are added, and 20% by weight or less of all isocyanate groups are converted to isocyanurate. A method for producing a modified aromatic polyisocyanate having an isocyanurate ring, which comprises adding a terminating agent if necessary. 2. A partially urethanized aromatic polyisocyanate, which is obtained by reacting 10% by weight or less of all isocyanate groups with an aromatic polyisocyanate and a hydroxyl group-containing compound having a molecular weight of 2000 or less and a functional number of 3 or less. The manufacturing method according to claim 1, wherein: