KR920000924B1 - A thermosetting resin and a method for producing it - Google Patents

Abstract

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Description

Method for producing thermosetting resin

The present invention relates to a method for producing a novel thermosetting resin having heat resistance, flame retardancy and high strength, and excellent in workability.

Generally speaking, addition polymerization of a compound having an organic polyisocyanate and an active hydrogen group is made of two kinds such as a polyurethane is produced when the organic polyisocyanate reacts with a polyhydric alcohol, and a polyurea is reacted with a polyamine. The reaction of the compounds of is well known, as represented by the various combinations to form a group of useful polymeric materials collectively termed polyurethanes.

However, even in the case of a compound having an active hydrogen group, for example, amino triazines are considered to have a very low reaction activity with isocyanates because their free amino groups are directly in direct contact with the triazine nuclei having very high electron intake properties. In addition, aminotriazines are usually solid and have a very high melting point, and there are very few examples of polymer materials prepared by the reaction of liquid organic polyisocyanates with amino triazines. Rather, no reaction occurs between these compounds. As it has been, this reaction is not yet fully elucidated.

On the other hand, the inventors of the present invention already know that the reaction between the organic polyisocyanate and amino triazines can produce an extremely hard and insoluble condensate in the course of research for developing a new heat resistant thermosetting resin. Although a patent application has been filed (see Japanese Patent Application Laid-Open No. 59-41320), if a thermosetting resin having excellent physical properties such as strength can be obtained, the applicability of the reaction between an organic polyisocyanate and a compound having an active hydrogen group is increased. I think it is very beneficial.

Accordingly, an object of the present invention is to provide a thermosetting resin having higher heat resistance and strength.

Another object of the present invention is to provide a flame retardant and thermosetting resin having high heat resistance and strength.

Another object of the present invention is to provide a thermosetting resin having high heat resistance and strength, flame retardancy and good workability.

It is a special object of the present invention to provide a method for producing the above-mentioned thermosetting resin.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described prior art to provide a thermosetting resin which is more high-strength, high heat-resistant and more workable, and the thermosetting resin of the present invention is a catalyst for promoting carbodiimide formation of isocyanate. At least one organic polyisocyanate and the like by using at least one of polycarbodiimide substantially produced from at least one organic polyisocyanate, or at least one catalyst of catalyzing the carbodiimide formation of isocyanates. At least one of polycarbodiimide and crosslinking agent having two or more active hydrogen groups in the molecule and at least one compound having an epoxy group in the molecule, or carbodies substantially produced while regulating molecular weight from at least one organic monoisocyanate It is obtained by reacting 1 or more types of compounds which promote the trimerization of a mead, The manufacturing method is the crosslinking agent which has 2 or more active hydrogen groups in 1 or more types of organic polyisocyanate, and 1 or more types of molecules, or At least one of the compounds having an epoxy group in the molecule, or at least one of the compounds for promoting the trimerization of the carbodiimide and at least one of the catalysts for promoting the carbodiimide of the isocyanate, or at least one organic At least one crosslinking agent having at least two active hydrogen groups in the polyisocyanate and at least one organic monoisocyanate and at least one molecule, or at least one compound having an epoxy group in the molecule, or at least one compound which promotes the trimerization of the carbodiimide And a catalyst containing a catalyst for promoting carbodiimidation of at least one isocyanate It is characterized by heating to a suitable temperature.

Although the present invention will be described in detail below, carbodiimide in which molecular weight is regulated using organic monoisocyanate is also referred to as organic polycarbodiimide.

In the invention regarding the said source by the inventors of this invention, a mixture of organic polyisocyanate and aminotriazine is heated to the temperature of 60 degreeC or more, and curable resin is obtained, and this heat resistance is heated by heating this curable resin to the temperature of 300 degreeC or more further. And it is proposed that the resin with flame retardancy can be obtained.

The inventors continued further studies thereafter, and the polycarbodiimide obtained from the organic polyisocyanate was crosslinked by a substance containing at least two or more active hydrogen groups in one molecule such as an aminotriazine compound, a bisimide compound, and a polyhydroxy compound. The present invention has been found to impart thermosetting properties to complete the present invention.

That is, the fundamental difference between the present invention and the above-mentioned source is that in the invention, organic polyisocyanate and aminotriazine are reacted under heating to obtain a thermosetting resin. Converting to carbodiimide, and then reacting the polycarbodiimide with a crosslinking agent or epoxy compound having two or more active hydrogen groups in the molecule or a trihydrate-promoting compound of carbodiimide to crosslink to obtain a novel thermosetting resin. have.

It is also known to react a carbodiimide bond with an active hydrogen compound, and attempts to modify polycarbodiimide to an active hydrogen compound are also known as polytetra when E.Dyers treat polycarbodiimide with hydrogen azide (HN ₃ ). Since it is already reported that a sol is obtained (Journal of Polymer Science 6,729-742 [1968]), what is obtained in this way is not a resin crosslinked with the polytetrazole, for example, and its physical properties are also satisfactory. As it did not, it lacked practicality.

Thus, the organic polyisocyanate used in the present invention is a compound having two or more isocyanate groups at its terminals and is, for example, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 2,4 and 2,6-tolylene di Mixture of isocyanates, crude tolylene diisocyanate, methylene diphenyl diisocyanate, crude methylene diphenyl diisocyanate, 4,4 ', 4 "-triphenyl methylene triisocyanate, 4,4'- dimethyl diphenyl methane- 2,2 ', 5.5'-tetra isocyanate, xylene diisocyanate, hexamethylene-1,6-diisocyanate, lysine diisocyanate methyl ester, hydrogenated methylene diphenyl isocyanate, m-phenylene isocyanate, naphthylene-1, 5- Diisocyanate, 1-methoxyphenyl-2, 4-diisocyanate, 4,4'-biphenylene diisocyanate, 3,3'-dimethoxy-4,4'-biphenyl diisocyanate, 3 , 3'-dimethyl-4,4'-biphenyl diisocyanate, 3,3'-dimethyl diphenylmethane-4,4'- diisocyanate, isophorone diisocyanate, etc. can be illustrated. Moreover, the so-called terminal isocyanate prepolymer obtained by using these organic polyisocyanate in stoichiometric excess with respect to a polyfunctional active hydrogen compound can be used, For example, 4,4'- diphenyl methane diisocyanate and poly- (epsilon)-are used. Terminal isocyanate prepolymers with caprolactone diol, polytetrahydrofuran ether diol and the like.

In addition, since the object of the present invention is to obtain a highly heat-resistant cured resin, it is not preferable to contain a large amount of aliphatic ester bonds and ether bonds which are inherently inferior in heat resistance.

Moreover, using after carrying out partial carbodiimide polyisocyanate beforehand does not change the nature of this invention at all.

Moreover, the organic monoisocyanate used by this invention is an organic compound which has one isocyanate group in a molecule | numerator, and this includes phenyl isocyanate, (ortho, meta, para)-tolyl isocyanate, dimethylphenyl isocyanate, cyclohexyl isocyanate, methyl isocyanate, chloro Although phenyl isocyanate, trifluoro methyl phenyl isocyanate, naphthal isocyanate, etc. can be illustrated, It is preferable to use aromatic isocyanate if importance is placed on heat resistance.

The crosslinking agent, which is the next element of the present invention, is, in principle, a compound containing two or more active hydrogen groups, a compound having an epoxy group, a trimerization promoting compound, or the like, for example, amino-s-triazine, 2-phenyl-4, 6-diamino triazine, 2-methyl-4,6-diaminotriazine, triazine derivative, 3,9-bis [2- (3,5-diamino-2,4,6-triazaphenyl) Compounds having phenolic hydroxyl groups such as ethyl] -2,4,8,10-tetraoxaspiro [5,5] undecane, cyanuric acid and its substituents, hydroquinone and 4,4'-isopropylidene diphenol , Diimide compounds such as urea dicyandi diamide, pyromellitic diimide, pyromellitic anhydride, diacid anhydrides such as 3,3'-4,4'-benzophenone tetracarboxylic anhydride, polyfunctional epoxy compounds and the like. Can be raised.

In particular, according to the present invention, as a compound capable of promoting the trimerization of carbodiimide, it is possible to use all the trimerization catalysts of organic isocyanates known to those skilled in the art in polyurethane chemistry as a result of research by the inventor of the present invention. And compounds having at least one tertiary nitrogen atom in a molecule such as diazabicycloundecene, P-dimethyl aminophenol, tris (dialkyl aminoalkyl) hexahydro-s-triazine, or organic acids or inorganics thereof Organic metal salts such as hydrochloric acid, sodium acetate, potassium acetate, sodium benzoate, or a mixed system of tertiary amine and alkylene oxide work well.

The third element of the present invention is a catalyst for promoting the carbodiimide formation of isocyanate, and various catalysts are used for this catalyst, but 1-phenyl-2-phosphorene-1-oxide and 3-methyl-2-phosphorene- 1-oxide, 1-phenyl-2-phosphorene-1-sulfide, 1-ethyl-2-phosphorene-1-oxide, 1-ethyl-3-methyl-2-phosphorene-1-oxide or these 3-phosphorene isomers are suitable in terms of yield and the like. The thermosetting resin of the present invention generates a polycarbodiimide by using a catalyst for promoting carbodiimide formation of isocyanate from one or more kinds of the above organic polyisocyanate, and the like, and a crosslinking agent having two or more active hydrogen groups in a molecule thereof, or It is obtained by adhering to a crosslinking reaction with at least one compound that promotes the trimerization of carbodiimide and is highly heat resistant or has high strength and is excellent in workability.

In addition, polycarbodiimide itself using organic polyisocyanate as a starting material is known (TWCampbell and JJ Monagle, J. Amer. Chem. Soc., 84, 1493 [1962]), and polycarbodiimide has a processability as a plastic. It is known that the resin is hard and soft when the molecular weight is regulated to the extent it has.

It is for this reason that the conventional polycarbodiimide could not be used practically as a compact resin or foam alone, and its purpose is to stabilize the polymer using the reactivity of the carbodiimide bond (e.g., Stabarxol P from Bayer) It was limited to).

In addition, there have been attempts to partially introduce polycarbodiimide bonds in order to improve their thermal stability in the production of polyurethane foams, but they cannot be said to be essentially polycarbodiimide resins.

The above-mentioned thermosetting resin of this invention can be manufactured by two types of this invention methods, for example, as demonstrated below.

First, one of the methods of the present invention is to prepare a composition containing each of the above-mentioned elements of the thermosetting resin of the present invention in an appropriate ratio, and to heat the composition to an appropriate temperature. In this method, the organic polyisocyanate is present in the presence of a carbodiimidation catalyst. First, the crosslinking agent having an active hydrogen group coexists in the molecule when substantially changed to polycarbodiimide, but in the presence of the catalyst, the carbodii is preferentially present in the presence of the catalyst because the crosslinking agent used in the present invention is very low in reactivity with organic polyisocyanate. Since the midmization reaction proceeds, it is thought that the reaction itself does not interfere.

However, if the crosslinking agent reacts with the organic polyisocyanate prior to the carbodiimide formation of the organic polyisocyanate, it will not act as a crosslinking agent or will introduce thermally weak bonds. In order to carry out the body imidation reaction, it is preferable in principle that the active hydrogen group of the crosslinking agent is as low as possible with respect to the organic polyisocyanate (for this reason, for example, at a system in which 4,4′-diamino-diphenyl methane coexists) It is difficult to make a body imidation reaction perform.

Carbonic acid gas is generated as the carbodiimidation reaction proceeds, so if a foam is desired as the final product, carbon dioxide gas is dispersed and maintained in the system, and if necessary, a bubble stabilizer such as polyalkoxy silicon may be added.

It is also possible to blend fibrous reinforcements, powders or crystalline fillers at this stage.

Also carbodiimidation does not need to be completed completely at this stage. To some extent carbodiimidization proceeds, the system solidifies and becomes a dendrite where residual isocyanate is observed but appears relatively stable and hardly changes over days to weeks.

The solidified dendritic product can be converted into a final cured product by heating at a temperature of 100 ° C. or more and 500 ° C. or less, preferably 150 ° C. or more and 400 ° C. or less, and a cured product of a shape can be obtained if heating is performed under pressure in a suitable mold. Since the dendritic product softens at a temperature of 150 ° C. or higher and then hardens rapidly, the thermoforming is also performed in a range of 150 ° C. to 400 ° C., preferably 100 ° C. or higher and 500 ° C. or lower.

In addition, the dendritic material may be used by grinding if necessary, or may be mixed with a fibrous reinforcing agent, powder or crystalline filler after grinding.

Meanwhile, the rest of the present invention first converts an organic polyisocyanate into a polycarbodiimide substantially in the presence of a catalyst that promotes carbodiimide formation of isocyanate, and a crosslinking agent having a two or more active hydrogen groups, a trimerization promoting compound, and the like. It mixes and heats this composition at a suitable temperature, In this method, a crosslinking agent may mix | blend the dendritic substance which arises, for example by polycarbodiimide-ization of organic polyisocyanate, and mix-disperses in this. Therefore, according to the method of the present invention, since the organic polyisocyanate is substantially changed to polycarbodiimide, even a crosslinking agent that is highly reactive to the organic polyisocyanate can be effectively used.

In any case, when the dendritic substance has a certain amount of residual isocyanate groups, it can be re-foamed by heating. In this case, the mold can be filled with foam to obtain a cured product of a desired shape. .

The thermosetting resin of the present invention is obtained by the reaction of a polycarbodiimide with a compound that promotes the trimerization of carbodiimide as described above. The greatest feature is high strength and heat resistance.

In addition, the resin of the present invention was excellent in thermal stability, and the polytetrazole showed a weight loss rapidly at around 250 ° C based on the result of thermogravimetric analysis.

On the other hand, in the above-mentioned inventors of the present invention, the organic polyisocyanate and aminotriazine are mixed and then heated to 60 to 160 ° C. to obtain a cured product, and then the cured product is heated to 300 to 400 ° C. for resoftening and foaming. Because it is highly heat resistant resin, two-step process is required, and because the final heating temperature reaches 300 ℃ or more and generates a large amount of carbon dioxide gas, processing is relatively difficult, but according to the method of the present invention, the heating temperature is lowered. Since it can suppress, the resin of this invention which has the outstanding characteristic as mentioned above can be manufactured easily.

In addition, one of the methods of the present invention has the advantage that the process is completed in one step, and the crosslinking agent and the like can be mixed uniformly as a whole. There is an advantage that can be.

Next, examples of the present invention will be described.

(1) A mixture obtained by thoroughly mixing 30 g of polycarbodiimide (number average molecular weight: about 1,000) and 0.3 g of diazabicyclo undecene sealed at the end of the terminal was press-molded at 150 ° C. for 5 minutes, and then at 200 ° C. It press-molded again for 10 minutes and obtained the yellow resin molded article.

The physical properties of this article are as follows.

Mill degree 1.22 g / cm ³

Flexural strength 322kg / cm ²

(2) 10 g of polycarbodiimide (number average molecular weight: about 2,000) sealed at the end is completely dissolved in 100 ml of N-methyl-2-pyrrolidone while completely dissolved, and 0.2 g of p-dimethylaminophenol is added to this solution, followed by another 5 minutes. Stirring was continued. The obtained solution was uniformly coated on a glass plate and dried for 5 minutes at room temperature and then for 30 minutes at 50 ° C for another 2 hours at 100 ° C to obtain a tough transparent film.

Infrared absorption spectrum of the film showed an absorption which is thought to be due to the structure 3 dimerization of polycarbodiimide in the vicinity of 1630 cm ^-1.

(3) 100 g of polycarbodiimide (number average molecular weight of about 2,500) sealed at the end was completely dissolved in 1000 ml of a tetrahydrofuran-trichlorethylene (2: 1) mixed solution under vigorous stirring. Stirring was continued for 30 minutes at room temperature, 0.5 g of N, N ', N "-tris (diethylaminopropyl) hexahydro-s-triazine was added and stirred, and the solution was then slowly heated. When the temperature in the system reached 50 ° C, the solution rapidly thickened to become a transparent gel product. The gelled material was pulverized and dried to obtain a white powder.

A yellow resin molded article was obtained by subjecting 30 g of the white powder to a mold at 200 ° C. for 25 minutes.

The physical properties of this resin molded article were as follows.

Mill degree 1.30 g / cm ³

Flexural strength 354kg / cm ²

(4) 500 g of polycarbodiimide (number average molecular weight about 4,000) sealed at the end, 150 g of potassium titanate, and 1 g of potassium acetate were ground and mixed in a bowl mill for 1 week.

Thus, 100 g of the white powder obtained was press-molded at 210 degreeC for 45 minutes in the metal mold | die, and the yellow resin molded product was obtained.

The physical properties of this molded article were as follows.

Mill degree 1.68 g / cm ³

Flexural Strength 602kg / cm ²

(5) 100 g of the polycarbodiimide (number average molecular weight about 2,200) sealed at the end and 1 g of diazabicyclo undecene were sufficiently mixed in the mortar. The obtained mixture was impregnated in 35 g of a glass long fiber strand mat maintained at 190 ° C. and cooled to room temperature to obtain a glass fiber reinforced resin, and the glass fiber reinforced resin was pressed at 230 ° C. for 5 minutes to obtain a reinforced molded article.

The physical properties of this molded article were as follows.

Mill degree 1.71 g / cm ³

Flexural strength 4,200kg / cm ²

Claims (14)

By treating at least one polycarbodiimide substantially produced from at least one organic polyisocyanate with a compound capable of catalyzing the trimerization reaction of carbodiimide by using at least one catalyst which promotes carbodiimide formation of isocyanates A method for producing a thermosetting resin having high heat resistance, characterized by the above-mentioned. The method for producing a thermosetting resin according to claim 1, wherein the polycarbodiimide is treated at a temperature of 100 ° C or more and 300 ° C or less with a compound capable of promoting the trimerization reaction of the carbodiimide. The method for producing a thermosetting resin according to claim 1 or 2, wherein the compound capable of promoting the trimerization reaction of carbodiimide is the same kind as the trimerization catalyst of organic isocyanate. The method for producing a thermosetting resin according to claim 3, wherein the compound capable of promoting the trimerization reaction of carbodiimide has at least one tertiary nitrogen atom in the molecule. 4. The compound according to claim 3, wherein the compound capable of catalyzing the trimerization reaction of carbodiimide is one selected from diazabicycloundecene, p-dimethylaminophenol, tris (dialkyl aminoalkyl) hexahydro-s-triazine. The above compound, or its organic acid and inorganic acid salt, The manufacturing method of the thermosetting resin characterized by the above-mentioned. The method for producing a thermosetting resin according to claim 3, wherein the compound capable of promoting the trimerization reaction of carbodiimide is an organic acid metal salt selected from sodium acetate, potassium acetate and sodium benzoate. The method for producing a thermosetting resin according to claim 3, wherein the compound capable of promoting the trimerization reaction of carbodiimide is a mixed system of tertiary amine and alkylene oxide. By using one or more catalysts for promoting carbodiimide formation of isocyanates, polycarbodiimide substantially produced from the at least one organic polyisocyanate and at least one organic monoisocyanate, A method for producing a thermosetting resin having high heat resistance, characterized by treating with a compound capable of promoting the quantification reaction. The method for producing a thermosetting resin according to claim 8, wherein the polycarbodiimide is treated as a compound capable of promoting the trimerization reaction of the carbodiimide at a temperature of 100 ° C or more and 300 ° C or less. The method for producing a thermosetting resin according to claim 8 or 9, wherein the compound capable of promoting the trimerization reaction of carbodiimide is the same kind as the trimerization catalyst of organic isocyanate. The method for producing a thermosetting resin according to claim 10, wherein the compound capable of promoting the trimerization reaction of carbodiimide has at least one tertiary nitrogen atom in the molecule. The compound according to claim 10, wherein the compound capable of catalyzing the trimerization reaction of carbodiimide is one selected from diazabicycloundecene, p-dimethyl aminophenol, tris (dialkyl aminoalkyl) hexahydro-s-triazine. The above compound, or its organic acid and inorganic acid salt, The manufacturing method of the thermosetting resin characterized by the above-mentioned. The method for producing a thermosetting resin according to claim 10, wherein the compound capable of promoting the trimerization reaction of carbodiimide is an organic acid metal salt selected from sodium acetate, potassium acetate and sodium benzoate. The method for producing a thermosetting resin according to claim 10, wherein the compound capable of promoting the trimerization reaction of carbodiimide is a mixed system of tertiary amine and alkylene oxide.