JPH031345B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a thermoplastic resin composition, and more particularly to a polyamide-imide resin composition for melt molding which has significantly improved thermal stability during melting. Polyamide-imide resin has excellent heat resistance, mechanical properties, electrical properties, and chemical resistance similar to polyimide resin, and also has melt processability that polyimide resin lacks, making it an important industrial material. has been attracting attention in recent years. However, although polyamide-imide resin has melt processability, its melt viscosity is originally extremely high, and injection molding requires extremely high processing temperatures and pressures. For this reason, when an ordinary molding machine is used, there is a problem in that some of the resin that remains for a long time decomposes, making it impossible to obtain a good molded product. As a method to solve such problems, a method has been proposed to lower the processing temperature by blending various thermoplastic resins with low melt viscosity (Japanese Patent Laid-Open No. 55-21461,
JP-A-55-80457, JP-A-55-102650). However, these methods cannot be said to be satisfactory as they inevitably impair the original excellent properties of the polyamide-imide resin. Under such circumstances, the present inventors conducted intensive research in order to provide a composition that solved the above-mentioned problems during melt molding without impairing the inherent excellent properties of polyamide-imide resin. The present inventors have discovered that when organic phosphite is blended with polyamide-imide, decomposition during melting is suppressed, and the present invention has been completed. That is, the present invention provides a polyamide-imide composition for melt molding which is substantially composed of an aromatic polyamide-imide and an organic phosphite and has improved stability during melting. Japanese Patent Publication No. 47-34551 discloses a composition comprising a polyamide-imide polymer, a solvent, and a release agent selected from the group consisting of phosphoric acid, phosphoric acid ester, phosphite, or strong organic acid. Systems containing imides and phosphites are already known. However, the composition contains a solvent as an essential component, and the purpose of using phosphite is to improve the releasability of cast films, which is meaningful only for systems containing a solvent. On the other hand, the composition of the present invention must not contain a solvent, and the purpose of incorporating an organic phosphite is to improve stability during melting, which is meaningless in a system containing a solvent. Furthermore, this effect of improving stability during melting is not observed in phosphoric acid or phosphoric acid esters, but is characteristic of organic phosphites. As described above, the composition of the present invention is completely different from the composition of the above-mentioned publication in both the purpose to be achieved and the essential requirements for achieving the purpose. Therefore, the present invention is unrelated to the invention disclosed in the above-mentioned publication, and furthermore, the effect of improving stability during melting has sufficient unexpectedness and independent utility that cannot be inferred from the effect of improving peelability in solution casting. -ing The aromatic polyamideimide in the present invention is
general formula Contains 50 mol% or more of repeating units represented by, and less than 50 mol% of other repeating units of the general formula Repeating unit and/or general formula represented by A polymer that may contain repeating units represented by Here, Ar ₁ is an aromatic trivalent residue, and is characterized in that the divalents to which the two carbonyl groups forming the acid anhydride group are bonded are on adjacent carbon atoms. A specific example of such Ar ₁ is

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[expression] and etc. R ₁ , R ₂ , R ₃ and R ₄ represent aromatic, aliphatic or alicyclic divalent residues, each of which has at least
70 mol% is occupied by aromatic divalent residues. Specific examples of such R ₁ , R ₂ , R ₃ and R ₄ are

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[Formula] and aromatic divalent residues such as nuclear substituted products thereof,

[Formula] -(CH ₂ ) ₆ - and other aliphatic divalent residues,

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Examples include divalent alicyclic residues such as [Formula]. R ₅ represents an aromatic, aliphatic or alicyclic tetravalent residue; specific examples include:

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[Formula] etc. are listed. Specific examples of aromatic polyamideimide in the present invention include etc. Various methods for producing these aromatic polyamideimides are known. For example, they include the production of acyl halide derivatives of aromatic tricarboxylic acid anhydrides and aromatic diamines into N,N-dimethylacetamide, N-
A method in which an aromatic tricarboxylic acid anhydride and an aromatic diamine are reacted in the presence of a polar organic solvent such as methylpyrrolidone or dimethyl sulfoxide (US Pat. No. 3,661,832, Japanese Patent Publication No. 15637/1983), A method of reacting aromatic tricarboxylic acid anhydride and aromatic diisocyanate in a polar organic solvent using a catalyst (French Patent No. 1515066), a method of reacting aromatic tricarboxylic acid anhydride and aromatic diisocyanate by heating (Japanese Patent Publication Publication No. 1973-
8910, Japanese Patent Publication No. 44-19274), and the so-called precipitation polycondensation method in which an aromatic tricarboxylic acid anhydride and an aromatic diisocyanate are subjected to a heating reaction in a polar aromatic solvent using a tertiary amine as a catalyst. (Japan Special Publication No. 54-44719). Among these, the last-mentioned method of precipitation polycondensation is the most preferred method because aromatic polyamide-imide can be obtained economically through a simple process. In this method, monomer raw materials such as trimellitic anhydride and diphenylmethane-4,4'-diisocyanate, trimellitic anhydride and diphenyl ether-4,4'-diisocyanate, or trimellitic anhydride and tolylene diisocyanate are used. In the presence of a tertiary amine such as triethylamine or triethylene diamine, a combination of
A heating reaction is carried out in a temperature range of 200°C to directly produce powdered aromatic polyamide-imide. The proportion of repeating units represented by the general formula () or () in the aromatic polyamide-imide of the present invention is less than 50 mol%, preferably 30 mol% or less, and when it is 50 mol% or more, the inherent properties of the polyamide resin are impaired. This is not desirable because it is not fully utilized. The organic phosphite in the present invention has the general formula (In the formula, R ₆ , R ₇ , and R ₈ represent the same or different aromatic, aliphatic, or alicyclic organic groups.)
This is a group of compounds represented by _R6 , _R7 and _R8
Specific examples include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group,
Examples include octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, octadecyl group, cyclohexyl group, phenyl group, cresyl group, nonylphenyl group, and benzyl group. Examples of organic phosphites represented by the general formula () include triethyl phosphite, tripropyl phosphite, tributyl phosphite, tripentyl phosphite, trihexyl phosphite, tricyclohexyl phosphite, trichloroethyl phosphite, and trioctyl phosphite. , tridecyl phosphite, trilauryl phosphite, triotadecyl phosphite, triphenyl phosphite, dimethyl-m-chlorophenyl phosphite, tricresyl phosphite, phenyl didecyl phosphite, diphenylpentyl phosphite, tri- Specific examples include benzyl phosphite, trioctyl trithiophosphite, trilauryl trithiophosphite, and the like. Preferred organic phosphites are triphenylphosphite, tricresylphosphite, triethylphosphite and tributylphosphite, especially triphenylphosphite. The mixing ratio of organic phosphite to aromatic polyamide-imide in the composition of the present invention substantially improves the stability of the aromatic polyamide-imide during melting, and does not impair the excellent properties of the aromatic polyamide-imide. It can be arbitrarily selected within the range, but usually 0.001 to 10 parts by weight, preferably 0.01 to 10 parts by weight, based on 100 parts by weight of aromatic polyamideimide.
It is 5 parts by weight. In general, if the amount is less than 0.001 part by weight, the effect of improving stability during melting is small;
If the amount is more than 1 part by weight, the heat resistance, which is an important characteristic of aromatic polyamideimide, is reduced, which is not preferable. In producing the composition of the present invention, the aromatic polyamideimide and the organic phosphite are mixed, and various known methods can be used for the mixing. For example, both may be mixed as they are, or both or one may be dissolved or suspended in an appropriate solvent and mixed, and then the solvent may be removed. It is effective to use a Henschel mixer, ball mill, ribbon blender, etc. Even if a small amount of fillers such as reinforcing agents, abrasion resistance improvers, flame retardance improvers, electrical property improvers, acid resistance improvers, etc. or other resins are added to the composition of the present invention, there will be no problem. I can't help it. Thus, the composition of the present invention can be stably melt-mixed and molded using a hot roll, a Banbury mixer, a Brabender, a press molding machine, an extrusion molding machine, an injection molding machine, etc. to give a uniform melt-molded product. Normal temperature for melt mixing or melt forming
A range of 300-400°C is chosen. The molded products obtained by melt-molding the composition of the present invention can be used for various purposes such as automobile parts, electrical/electronic parts, etc. by taking advantage of their excellent heat resistance, mechanical properties, electrical properties, and chemical resistance. Its industrial value is enormous. EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but the scope of the present invention is not limited by these Examples. In addition, parts in the examples represent parts by weight. Reference Example 1 384 g of trimellitic anhydride, 500.5 g of diphenylmethane-4,4'-diisocyanate, 6 g of phthalic anhydride, and nitrobenzene were placed in a 5-separable flask equipped with a distillate extractor, thermometer, nitrogen blowing tube, and stirrer. 3.2 was taken and heated to an internal temperature of 140°C while stirring. A solution of 30.4 g of triethylamine dissolved in 400 ml of nitrobenzene was added thereto, and the reaction was continued at 140°C for 5 hours.
During this time, a yellow polymer precipitated and the system became a slurry. After cooling, 1 part of acetone was added to the system to separate the precipitated polymer. The wet polymer was boiled and washed with acetone, and then vacuum-dried at 120° C. for 24 hours to obtain 714.8 g of a yellow powdery polymer. It was confirmed by infrared absorption spectrum that the polymer was aromatic polyamideimide. The powdered aromatic polyamideimide in N-methylpyrrolidone at 25°C, 0.5g/
The reduced viscosity measured at a concentration of dl was 0.964 dl/g. Reference example 2 Diphenylmethane-4,4'-diisocyanate
A powdered aromatic compound with a reduced viscosity of 0.712 dl/g was prepared in the same manner as in Reference Example 1, except that 500.5 g was replaced with 504.5 g of diphenyl ether-4,4'-diisocyanate and 6 g of phthalic anhydride was replaced with 24 g of phthalic anhydride. Polyamideimide was produced. Examples 1-4, Comparative Examples 1-2 Aromatic polyamideimide produced in Reference Example 1
A solution prepared by dissolving 1 part of the organic phosphite shown in Table 1 in 500 parts of acetone was added to 100 parts, the acetone was distilled off, and the mixture was vacuum-dried at 120° C. for 3 hours to produce a polyamide-imide resin composition. These compositions were extruded using a full-flight single-screw extruder with L/D=15/1 and a diameter of 20 mm at a cylinder temperature of 340° C., and the state of gas generation at the exit of the extruder, the state of the formed strands, etc. were observed. These results are the first
Shown in the table. Further, Table 1 also shows the results when no organic phosphite was added and when other phosphorus compounds were added as comparative examples. From the results shown in Table 1, it is clear that the composition of the present invention containing an organic phosphite has good melting stability.

[Table] Examples 5 to 6, Comparative Examples 3 to 4 Organic phosphite 1 was added to the aromatic polyamideimide obtained in Reference Example 2.
The compositions produced in the same manner as in Example 1 except that the amounts of triphenyl phosphite were changed to those shown in Table 2 were evaluated in the same manner as in Example 1, and the physical properties of the obtained strand press-formed products were evaluated. I conducted an evaluation. These results are shown in Table 2.

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Claims (1)

[Claims] 1. Substantially (a) aromatic polyamideimide resin 100
Parts by weight and (b) general formula (In the formula, R ₆ , R ₇ and R ₈ represent the same or different aromatic, aliphatic or alicyclic organic groups.)
A polyamide-imide resin composition for melt molding which has improved stability during melting and comprises 0.001 to 10 parts by weight of an organic phosphite represented by: 2. The polyamide-imide resin composition according to claim 1, wherein the organic phosphite is selected from the group consisting of triphenyl phosphite, tricresyl phosphite, triethyl phosphite and tributyl phosphite. 3 Powdered aromatic polyamide-imide produced by a method of precipitation polycondensation of aromatic tricarboxylic acid anhydride and aromatic diisocyanate in a nitrobenzene and/or nitrotoluene solvent using a tertiary amine as a catalyst. The polyamide resin composition according to claims 1 and 2, which is an aromatic polyamideimide. 4. The polyamide-imide resin composition according to claim 1, wherein the organic phosphite is triphenyl phosphite.