JPH056565B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for producing a novel thermosetting resin that has heat resistance, flame retardancy, high strength, and excellent workability. [Prior Art] Generally speaking, addition polymerization of an organic polyisocyanate and a compound having an active hydrogen group means that, for example, when an organic polyisocyanate reacts with a polyhydric alcohol, a polyurethane is produced;
It is well known that the reaction of these two types of compounds can be combined in various ways to form a group of useful polymeric substances collectively called polyurethanes, such as when reacting with polyamines to produce polyurea. It is that you are. However, even if the compound has an active hydrogen group, aminotriazines, for example, are thought to have very low reaction activity with isocyanates because their free amino groups are directly connected to the triazine nucleus, which has extremely high electron-withdrawing properties. In addition, aminotriazines are usually solid and have very high melting points, and are almost insoluble in organic polyisocyanates, which are usually liquids. This reaction is still not completely understood, as there are very few examples of the substance being produced, and it was thought that no reaction occurred between these compounds. [Problems to be Solved by the Invention] Meanwhile, in the course of research to develop a new heat-resistant thermosetting resin, the inventors of the present invention discovered that the reaction between the above-mentioned organic polyisocyanate and aminotriazines caused an extremely Having learned that a hard, insoluble and infusible condensate can be produced, he has already filed a patent application for this invention (see Japanese Patent Laid-Open No. 59-41320). If an excellent thermosetting resin can be obtained, the applicability of the reaction between an organic polyisocyanate and a compound having an active hydrogen group will increase, and it is considered to be very beneficial. [Means for Solving the Problems] The present invention was made against the background of the above-mentioned prior art, with the object of providing a method for producing a thermosetting resin that has higher strength, higher heat resistance, and is more workable. Its composition consists of one or more organic polyisocyanates and one or more 2 molecules in the molecule.
A composition comprising a crosslinking agent having an active hydrogen group as described above and one or more catalysts that promote carbodiimidation of isocyanate is heated to an appropriate temperature, or one or more organic polymers are heated to an appropriate temperature. reacting an isocyanate in the presence of one or more catalysts that promote carbodiimidization of the isocyanate to substantially form a polycarbodiimide;
mixing the polycarbodiimide and one or more crosslinking agents having two or more active hydrogen groups in the molecule,
This composition is characterized by being heated to an appropriate temperature. The present invention will be explained in detail below. In the invention related to the above-mentioned prior application by the inventors of the present invention, a curable resin is obtained by heating a mixture of an organic polyisocyanate and an aminotriazine to a temperature of 60°C or higher, and this curable resin is heated to a temperature of 300°C or higher.
It is disclosed that by heating to a temperature above, a resin having even higher heat resistance and flame retardance can be obtained. After further research, the inventors discovered that the polycarbodiimide obtained from the organic polyisocyanate contains at least two or more active hydrogen groups in one molecule, such as an aminotriazine compound, a bisamide compound, or a polyhydroxy compound. The present inventors have discovered that a thermosetting resin can be obtained by crosslinking with a substance, and have completed the present invention. That is, the fundamental difference between the present invention and the invention related to the earlier application is that in the earlier invention, an organic polyisocyanate and an aminotriazine were reacted under heating to obtain a thermosetting resin, whereas the present invention In this, organic polyisocyanate etc. are treated in the presence of a catalyst,
First, it is substantially converted into polycarbodiimide,
Next, this polycarbodiimide is reacted with a crosslinking agent having two or more active hydrogen groups in the molecule to be crosslinked to obtain a novel thermosetting resin. It is known that carbodiimizo bonds react with active hydrogen compounds, and attempts to modify polycarbodiimide with active hydrogen compounds have also been made, for example.
E. Dyer et al. have reported that polytetrazole can be obtained by treating polycarbodiimide with hydrogen azide (NH ₃ ) (Journal of Polymer
Science 6 , 729-742 [1968]), but the product obtained in this way is not a crosslinked resin with the polytetrazole mentioned above, and also has good physical properties. As if it weren't for real, it was all about practicality. The organic polyisocyanate used in the present invention is a compound having two or more isocyanate groups at the end, such as 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 2,4 and 2,4-tolylene diisocyanate. Mixture of 2,6-tolylene diisocyanate, crude tolylene diisocyanate, methylene diphenyl diisocyanate, crude methylene diphenyl diisocyanate, 4,4',
4″-triphenylmethylene triisocyanate,
4,4'-dimethyldiphenylmethane-2,2',
5,5'-tetraisocyanate, xylene diisocyanate, hexamethylene-1,6-diisocyanate, lysine diisocyanate methyl ester, polymethylene polyphenyl isocyanate, hydrogenated methylene diphenyl isocyanate, m-phenylene diisocyanate, naphthylene-1, 5-
Diisocyanate, 1-methoxyphenyl-2,
4-diisocyanate, diphenylmethane-4,
4'-diisocyanate, 4,4'-biphenylene diisocyanate, 3,3'-dimethoxy-4,4'-
Biphenyl isocyanate, 3,3'-dimethyl-
4,4'-biphenyl diisocyanate, 3,3-
Examples include dimethyldiphenylmethane-4,4'-diisocyanate and isophorone diisocyanate. It is also possible to use so-called terminal isocyanate prepolymers obtained by using these organic polyisocyanates in stoichiometric excess with respect to the functional active hydrogen compound, such as 4,4'-terminated isocyanate prepolymers. Included are terminal isocyanate prepolymers of diphenylmethane diisocyanate and poly-ε-caprolactone diol, polytetrahydrofuran ether diol, and the like. Incidentally, since the purpose of the present invention is to obtain a highly heat-resistant cured resin, it is not preferable to contain a large amount of alpha ester bonds and ether bonds, which inherently have poor heat resistance. Moreover, using the polyisocyanate after partially carbodiimidizing it does not change the essence of the present invention in any way. The next element of the present invention, the crosslinking agent, is, in principle, a compound or mixture containing two or more active hydrogen groups in its molecule, such as amino-S-triazine, 1
-Phenyl-3,5-diaminotriazine, 1-
Methyl-3,5-diaminotriazine, 1,3,
Triazine derivatives such as 5-trihydroxytriazine, 3,9-bis[2-(3,5-diamino-
2,4,6-triazaphenyl)ethyl]-2,
4,8,10-tetraoxaspiro[5,5]undecane, cyanuric acid and its substituted products, hydroquinone, compounds with phenolic hydroxyl groups such as 4,4'-isopropylidene diphenol, urea, dicyandiamide, pyromellit diimide Diimide compounds such as pyromellitic anhydride, 3,
Examples include diacid anhydrides such as 3'-4,4'-benzophenonetetracarboxylic anhydride, polyfunctional epoxy compounds, and the like. The third element of the present invention is a catalyst that promotes carbodiimidation of isocyanate, and although various catalysts can be used, 1-phenyl-
2-phosphorene-1-oxide, 3-methyl-2
-Phosphorene-1-oxide, 1-phenyl-2
-phosphorene-1-sulfide, 1-ethyl-2
-phosphorene-1-oxide, 1-ethyl-3-
Methyl-2-phospholene-1-oxide and 3-phospholene isomers thereof are preferred in terms of yield and other aspects. The thermosetting resin according to the present invention is produced by producing polycarbodiimide from one or more of the above-mentioned organic polyisocyanates by using a catalyst that promotes the carbodiimidation of isocyanate, and adding two or more active hydrogen groups into the molecule. It is obtained by subjecting it to a crosslinking reaction with one or more of the above-mentioned crosslinking agents, and is highly heat resistant, has high strength, and has excellent processability. Incidentally, polycarbodiimide itself using organic polyisocyanate as a starting material is publicly known (TW
Camp-bell and JJMonagle, J.Amer.Chem.
Soc., 84 . 1493 [1962]), but if the molecular weight of polycarbodiimide is controlled to the extent that it can be processed as a plastic, the resin will become hard and brittle, and if the molecular weight is increased to the extent that it has sufficient strength, It is known that almost all plastics lose their workability. It is for these reasons that polycarbodiimide could not be put to practical use as a single dense resin or foam in the past, and its use was as a stabilizer for polymers that utilizes the reactivity of carbodiimide bonds. (For example, it was limited to STABAXOL P [trade name] by Vile Corporation). Furthermore, in the production of polyurethane foam, attempts have been made to partially introduce polycarbodiimide bonds in order to improve its thermal stability, but these cannot essentially be called polycarbodiimide resins. The thermosetting resin according to the present invention described above can be produced, for example, by the following two types of methods according to the present invention. First, one of the methods of the present invention is to prepare a composition containing the above-mentioned components of the thermosetting resin according to the present invention in appropriate proportions, and to heat the composition to an appropriate temperature. When organic polyisocyanate is first substantially converted into polycarbodiimide in the presence of a carbodiimidation catalyst, a crosslinking agent having an active hydrogen group in the molecule coexists. If the reactivity towards polyisocyanate is very low, the carbodiimidation reaction will proceed preferentially in the presence of the catalyst, and therefore it is considered that there will be no problem in the progress of the reaction itself. However, if the crosslinking agent reacts with the organic polyisocyanate prior to carbodiimidation of the organic polyisocyanate, it may not act as a crosslinking agent;
Alternatively, since it would introduce a thermally weak bond, in order to carry out the carbodiimidation reaction in a system in which an organic polyisocyanate and a crosslinking agent coexist as described above, in principle, the activity of the crosslinking agent must be It is desirable that the hydrogen group has as little activity as possible with respect to the organic polyisocyanate (for this reason, for example, it is difficult to carry out the carbodiimidization reaction in a system in which 4,4'-diamino-diphenylmethane coexists). . Carbon dioxide gas is generated as the carbodiimidation reaction progresses, so if you want a foam as the final product, you can disperse and maintain the generated carbon dioxide gas in the system, and if necessary, use polyalkoxy A bubble stabilizer such as silicone may be added. Also, fibrous reinforcing materials, powder or crystalline fillers can be added at this stage. Incidentally, the carbodiimidation does not need to be completely completed at this stage. When carbodiimidation progresses to a certain extent, the system solidifies and becomes a resin-like substance in which residual isocyanate is observed, but it is relatively stable and appears to hardly change over several days to several weeks. By heating the solidified resinous material to a temperature of 100°C or higher and 500°C or lower, preferably 150°C or higher and 400°C or lower, it can be converted into a final cured product, and the heating is carried out under pressure in an appropriate mold. If so, a cured product in the desired shape can be obtained, but since the resinous material softens at a temperature of 150°C or higher and then hardens rapidly, this hot-pressing molding is also carried out at a temperature of 100°C or higher and 500°C or lower, preferably 150°C or higher and 400°C or higher.
It shall be carried out within the range of ℃. Note that the resin-like material may be used after being crushed if necessary, or it may be mixed with a fibrous reinforcing material, a powdered or crystalline filler, etc. after being crushed. On the other hand, in the remaining method of the present invention, organic polyisocyanate is first made to substantially form polycarbodiimide in the coexistence of a catalyst that promotes carbodiimidation of isocyanate, and then the above-mentioned crosslinking agent having two or more active hydrogen groups is added to the polycarbodiimide. The composition is mixed and heated to an appropriate temperature. In this method, the crosslinking agent is mixed and dispersed in, for example, pulverized resinous material produced by polycarbodiimidation of organic polyisocyanate. All you have to do is mix them together. According to the method of the present invention, the organic polyisocyanate is substantially converted into polycarbodiimide, so even a crosslinking agent that is highly reactive to the organic polyisocyanate compound cannot be used effectively. can. In either method, if the resin material has a certain amount of residual isocyanate groups, it can be re-foamed by heating, and in this case, the mold is filled with foam to form the desired shape. It can also be made into a cured product. [Operations and Effects of the Invention] As mentioned above, the thermosetting resin of the present invention is obtained by reacting polycarbodiimide with a crosslinking agent having an active hydrogen group, and its greatest characteristics are high strength and heat resistance. It's in the sex. That is, when an example of the resin according to the present invention (according to Example 2 described below) and the resin according to the prior invention (according to Example 5) were compared, the results shown in the table below were obtained. be.

〔Example〕

Next, examples of the present invention will be described. 4,4'-diphenylmethane diisocyanate
125 g and 7 g of 1,3,5-triamino-S-triazine were thoroughly mixed with a high-speed stirrer, and then 3-methyl-1-phenylphosphorene-1-
0.2 g of oxide was added. When the mixture was heated to 130° C., it gradually foamed, and after 2 hours, a coarse foam with a light yellow color was obtained. After crushing this foam with an impact crusher,
The material molded for 5 minutes at 230° C. and a pressure of 50 kg/cm ² showed the following physical properties. Density 1.18g/cm ^3Bending strength 172Kg/cm ^2Limiting oxygen index 40 Water absorption 0.3% (boiled for 2 hours) Weight loss rate up to 400℃
3% (heating rate 5°C/min) 125 g of 4,4'-methylene diphenyl diisocyanate and 17 g of 1,3,5-triamino-S-triazine were thoroughly mixed with a high-speed stirrer, and then 3-methyl-1- Phenylphosphorene-1
-0.2 g of oxide was added and a yellow foam was obtained in the same manner as in the example. This foam is 10cm x 10cm
Cut it into a 2cm rectangular parallelepiped and place it in a mold at 230℃ for 50 minutes.
When molded for 5 minutes at a pressure of Kg/cm ² , a yellow molded product was obtained, and the physical properties of this product were as follows. Density 1.25 g/cm ³ Bending strength 186 Kg/cm ² Limit oxygen index 45 Water absorption 0.3% (boiling for 2 hours) Weight loss rate up to 400°C 2% Liquid MDI (partially carbodiimidized isocyanate, manufactured by Kasei Apgeyon, 143L) 143g,
1,3,5-triamino-S-triazine 6
g, 3-methyl-1-phenylphosphorene-1
- A yellow foam was obtained from 0.15 g of oxide in the same manner as in the example. The properties of this foam were almost the same as those obtained in the Examples. In the examples, 1-phenyl-
A reddish-brown foam was obtained in exactly the same manner except that 3,5-diamino-S-triazine was used. This foam was pulverized and molded at 230° C. and 50 kg/cm ² for 5 minutes, and the resulting resin had the following physical properties. Density 1.23 g/cm ³ Bending strength 158 Kg/cm ² Limiting oxygen index 38 Water absorption 0.3% Weight loss rate up to 400℃ 5% 4,4'-Diphenylmethane diisocyanate
125 g, 1,3,5-triamino-S-triazine, 10 g, and 2 g of a silicone surfactant (CF-2080 manufactured by Toray Silicone) were thoroughly stirred with a high-speed stirrer, and then 3-methyl-1-phenyl-
The mixture to which 0.15 g of phosphorene-1-oxide was added was heated at 130 DEG C. for 2 hours, gradually foaming, and a yellow hard foam consisting of fine bubbles was obtained. The density of the foam is 0.06g/ ^cm3 ,
Even when heated up to 200℃ in air, it hardly deforms.
It maintained its strength. In an example, the mixture was impregnated into 50 g of long glass fiber strand mat, and then
A glass fiber reinforced foam was obtained by heating at 100°C for 3 hours. This glass fiber reinforced foam was heated at 230℃ and 50Kg/
Molding was performed at a pressure of cm ² for 5 minutes to obtain a glass fiber reinforced molded product. The physical properties of this reinforced molded product were as follows. Density 1.68 g/cm ³ Bending strength 3500 Kg/cm ² Limiting oxygen index 48 Sharpie impact strength 25 Kg-cm< The glass fiber reinforced foam obtained in the example was
Molding was carried out for 30 minutes at 380° C. and a pressure of 50 Kg/cm ² to obtain a dark brown molded product. The physical properties of this molded product were as follows. Density 1.65g/cm ³ Bending strength (at room temperature) 3200Kg/cm ² Bending modulus (at room temperature) 128000Kg/cm ² Bending strength (150℃) 3320Kg/cm ² Bending modulus (150℃) 130000Kg/cm ² 4 ,4'-diphenylmethane diisocyanate
125 g, 4,4'-isopropylidene-diphenol, 10 g, and 0.2 g of 3-methyl-1-phenylphosphorene-1-oxide were mixed with a high-speed stirrer,
When heated to 100°C, foaming gradually occurred, and after 3 hours, a white, fine-celled, slightly flexible foam was obtained. The density of the foam was 0.03 g/cm ³ . When this foam was placed in a mold at 230°C and gradually compressed, a foam with even higher density was obtained. density
Foam compressed to 0.1g/ ^cm3 at 200℃
It hardly deformed and maintained its strength even when heated up to that point. Mix 125 g of 4,4'-methylene diphenyl diisocyanate and 0.1 g of 3-methyl-1-phenyl-2-phospholene-1-oxide, and heat at 130°C.
After heating for 3 hours, a white foam was obtained. The foam was crushed and then 7 g of 1,3,5-
A powder molding material was prepared by mixing with triamino-S-triazine and mixing in a ball mill for 24 hours. The physical properties of the molded product obtained by molding this molding material at 230° C. and a pressure of 50 kg/cm ² for 5 minutes were almost the same as those obtained in the examples.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the results of thermogravimetric analysis of the resin of the present invention and polytetrazole, where the solid line represents the results of the resin of the present invention in air, and the dotted line represents the results of polytetrazole in a nitrogen stream. show.

Claims (1)

[Scope of Claims] 1. A composition comprising one or more organic polyisocyanates, one or more crosslinking agents having two or more active hydrogen groups in the molecule, and one or more catalysts that promote carbodiimidation of isocyanates. A method for producing a thermosetting resin, which comprises heating a material to an appropriate temperature. 2. The method according to claim 1, wherein the crosslinking agent is aminotriazine or a derivative thereof. 3. The method according to claim 1, wherein the crosslinking agent is 4,4'-isopropylidenediphenol or a derivative thereof. 4 Substantially producing polycarbodiimide by reacting one or more organic polyisocyanates with one or more catalysts that promote the carbodiimidation of isocyanates, and the polycarbodiimide and one or more organic polyisocyanates containing two or more in the molecule. 1. A method for producing a thermosetting resin, which comprises mixing the composition with a crosslinking agent having an active hydrogen group and heating the composition to an appropriate temperature. 5. The method according to claim 4, wherein the crosslinking agent is aminotriazine or a derivative thereof. 6. The method according to claim 4, wherein the crosslinking agent is 4,4'-isopropylidenediphenol or a derivative thereof. 7. The method according to claim 4, wherein the crosslinking agent is 4,4'-diaminodiphenylmethane or a derivative thereof.