JPH0284464A - Polyamide-imide resin composition - Google Patents

Abstract

PURPOSE:To obtain the title composition suitable for automobile parts, etc., having improved water vapor absorption without damaging heat resistance, moldability, etc., by blending a specific amorphous thermoplastic polyamide-imide resin with a specific amount of a high-melting crystalline polyamide-imide resin. CONSTITUTION:(A) 10-70wt.%, preferably 10-50wt.% polyamide-imide resin which comprises repeating units shown by formula I and formula II as main structural units and the molar ratio of the formula I/II=(100/0)-(5/95), preferably (90/10)-(10/90) is blended with (B) 90-30wt.%, preferably 90-50wt.% polyamide- imide resin which comprises a repeating unit shown by formula III as a main structural unit. In the formulas, Ar has 5-70mol% bifunctional residue shown by formula IV and 95-30mol% bifunctional residue shown by formula V based on total amounts of the units shown by formula I and formula II, X is group shown by formula VI, etc., a is 0-2, b and c are 0-4 and x is 1-500.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a polyamide-imide resin composition that has good heat resistance and moldability, and has improved hygroscopicity.

[Conventional technology]

Polyamide-imide resin has excellent heat resistance and mechanical properties, and in addition, except for crystalline resins, it can be injection molded with high productivity, so it is widely used in various fields.
It is used as a high-performance material.

For example, JP-A-61-195127 discloses that the repeating units represented by the following general formulas (I) and (ff) are the main structural units, and the molar ratio of (I) and (II) (
A polyamide-imide resin having a ratio I/II) of 100/0 to 5/95 is disclosed.

(wherein Ar is a direct bond with (I) and (old-style whole, -o-, -s-, -5oz--c-1 or -C~,
R2 is an alkyl group, R2 is an alkyl group having 1 to 4 h of carbon atoms, a fluorine-substituted alkyl group, or a phenyl group, a is Oll or 2, C is an integer of O to 4, and X is 1 to 5
Indicates an integer of 00. ) The above-mentioned polyamide-imide resin is of poor quality and has good thermal stability and fluidity in the temperature range of 300 to 400°C, so it can be molded into a desired shape by injection molding.

On the other hand, crystalline polyamideimide resins are also well known, although they do not have melt moldability.

[Problem to be solved by the invention]

However, the polyamide-imide resin disclosed in JP-A No. 61-195127 has the drawback of high hygroscopicity, which causes problems such as reduced dimensional accuracy, foaming and blistering at high temperatures. arise.

Therefore, the inventor of the present invention has conducted intensive studies on methods for reducing the hygroscopicity without impairing the heat resistance 1 mechanical properties, melt moldability, etc. of polyamide-imide resin, and as a result, it has been found that a specific crystalline polyamide-imide resin can be blended. We have found that this is effective and have arrived at the present invention.

[Means to solve the problem]

That is, the present invention has A, repeating units represented by general formulas (I) and (II) as main structural units, and a molar ratio (I/I[) of (I) and (ff) of 10010 to 5/95. 10 to 70% by weight of a polyamideimide resin, and 90 to 30% by weight of a polyamideimide resin whose main structural unit is B, a repeating unit represented by the general formula (I[r)]
The present invention provides a polyamide-imide resin composition comprising:

(In the formula, Ar is, and (ff) (III) The whole of 2 or -C-R, is a methyl group, R2 is an alkyl group having 1 to 4 carbon atoms, a fluorine-substituted alkyl group, or a phenyl group, a
is 0, ■ or 2, b and C are integers from 0 to 4, X is 1
Indicates an integer between ~500. ) In the composition of the present invention, the polyamide-imide resin used as component A is a copolymer whose main structural units are repeating units represented by general formulas (I) and (n). and (rl) nomolar ratio (I/ff)
is 100/0 to 5/95, preferably 90/0
10 to 10/90 is good.

If the ratio of (U) exceeds 95 mo 1%, the physical properties will deteriorate, which is not preferable.

Further, the component ^r in formulas (I) and (II) is composed of a two-component mixture having the following structure and composition ratio.

is a direct bond, and a specific example of S- (R+)i Ar+ unit is (here, X, R,, a, and C are as described above). %, it is not preferable because the toughness and mechanical strength of the polyamide-imide decrease. In addition, the ratio of Arz units is 951
If it exceeds 1101%, the melt moldability of the polyamideimide decreases, which is not preferable. A more preferred embodiment is Ar
, unit 20-50mo 1%.

The Ar2 unit is 80 to 50 mo1%.

Here, specific examples of each unit are as follows: 8r2 As a specific example of a unit, (R,).

It is.

C11゜ C) 13 C.F.

Examples include Hff lh and their side chain methyl group-substituted derivatives.

Specific examples of formula (I) composed of specific examples of the above units include the following, where X is 1 to 500, preferably 1 to 10, more preferably 1 to 4.

Such polyamideimide resins having formulas (I) and (II) can be produced by known methods, for example, JP-A-61-195.
It can be synthesized by the method detailed in Japanese Patent No. 127.

The polyamideimide resin used as component B in the composition of the present invention is a polymer whose main structural unit is a repeating unit represented by the general formula (wherein R3, a and b are as described above). However, the details are disclosed in (R+J- (RIJI CRI)-), Japanese Patent Publication No. 57-9744, etc.

Further, in the polyamide-imide resin used in the present invention, a part of the imide bond is a ring-closing precursor, and examples thereof include methyl side chain-substituted derivatives thereof. The above-mentioned polyamide-imide resin is a high-melting point crystalline polymer, and although it is difficult to melt mold and is not practical when used alone, it has excellent thermal properties and low water absorption. The synthesis method of such polyamideimide resin is known, for example,
-15637, and those published in Japanese Patent Publication No. 56-16171 are also included.

The composition of the present invention has formulas (I) and (II) as component A.
) Polyamideimide resin represented by 10 to 70% by weight
(preferably 10 to 50% by weight) and, as component B, 90 to 30% by weight (preferably 90 to 50% by weight) of a crystalline polyamideimide resin represented by formula (III). Here, the crystalline polyamideimide resin is 3
If it is less than 0% by weight, there is no effect of improving hygroscopicity, which is undesirable, and if it exceeds 90% by weight, melt moldability is significantly impaired, which is not preferred.

The logarithmic viscosity of the polyamide-imide resin was measured in N-methylpyrrolidone at a concentration of 0.5 g/a and a temperature of 30°C, and was 0.2 to 5°Od! 7g, preferably 0.3-2
．． Good Oa/g.

If the logarithmic viscosity is less than the above range, the mechanical strength will decrease, which is undesirable, and if it exceeds the above range, the melt viscosity will become too high (too much), making molding difficult, which is not preferable.

A feature of the composition of the present invention is that a high-melting point crystalline polyamide-imide resin is blended with a non-grade thermoplastic polyamide-imide resin.

Here, by adding a polyamide consisting of (() and (n), the hygroscopicity can be improved, but at the same time, a decrease in moldability is inevitable.However, the composition of the present invention maintains moldability. At the same time, it has an excellent property of improving hygroscopicity (see Comparative Example 3).

Two methods are generally used to mix and prepare the composition of the present invention: a solution mixing method and a melt mixing method.

In the solution mixing method, a polyamide-imide resin as an A component or a polyamide acid as a precursor thereof, and a polyamide acid as a polyamide-imide resin as a component as a component B or a polyamide acid as a precursor thereof are respectively mixed in a polar solvent such as N,N-dimethylformamide,
It is carried out by dissolving in N,N-dimethylacetamide, N-methylpyrrolidone, etc., and then subsequently mixing the two types of solutions.

In the case of a polyamide acid mixture, a ring-closing reaction is subsequently performed to convert it into polyamideimide.

The melt blending method also uses equipment used to melt blend ordinary rubbers or plastics, such as hot rolls,
A Banbury mixer, Brahender, extruder, etc. can be used.

The mixing operation is continued until a homogeneous formulation is obtained.

The mixing temperature is set above the temperature at which the blended system can be melted and below the temperature at which the blended system begins to thermally decompose, and the temperature is usually selected from the range of 250 to 400°C, preferably 300 to 380°C. .

The composition of the present invention may contain the following fillers in an amount of 70% by weight or less, if necessary.

(a) Wear resistance improvers: graphite, carborundum, silica powder, molybdenum disulfide, fluororesin, etc., (b
) Reinforcement materials: glass fiber, carbon fiber, boron fiber, silicon carbide fiber, carbon whisker, asbestos fiber,
Asbestos, metal fibers, etc. (C) Flame retardant improvers such as antimony dioxide, magnesium carbonate, calcium carbonate, etc. (d
) Electrical property improvers: clay, mica, etc. (e) Tracking resistance improvers: asbestos, silica, graphite, etc.
f) Acid resistance improver: barium sulfate, silica, calcium metasilicate, etc., (g) Thermal conductivity improver: Metal powder such as iron, zinc, aluminum, copper, etc., (h) Other glass beads, glass spheres, Contains synthetic and natural compounds #yJi that are stable at temperatures above 300°C, such as calcium carbonate, alumina, talc, diatomaceous earth, hydrated alumina, mica, shirasu balloons, asbestos, various metal oxides, and inorganic pigments.

The composition of the present invention can be subjected to injection molding or extrusion molding, which are highly productive molding methods, but there is of course no problem in applying it to other compression molding, sintering molding, etc.

〔Example〕

Hereinafter, the present invention will be further explained in detail by giving Examples. In addition,
In the examples, the logarithmic viscosity (η1nh) of the polymer is N-
Concentration 0.5g/d in methylpyrrolidone! , temperature 30℃
Measured under the following conditions.

Moreover, the water absorption rate was measured after 48 hours of immersion in 80° C. hot water.

Production examples: Japanese Patent Publication No. 56-16171 and Japanese Unexamined Patent Publication No. 61-19
Based on the method disclosed in Publication No. 5127, trimellitic anhydride monochloride and the corresponding aromatic diamines were reacted in N,N-dimethylacetamide to synthesize a polyamideimide resin having the following structure. .

(A-1) (A-2) (A-1') 771nh=0.65d! /g (A-3) 7) jnh=0.52/J/g 11nh=0.61 d17g v 1nh=0.60/j/g (B-1) η1nh=68aj/g (B-2) 771nh = 0.50 dl/g Example 1.2 and Comparative Example 1.2 After tri-blending the polyamide-imide resin powders of (A-1) and (B-1) with the composition shown in Table 1, a biaxial pressing ratio of 30 inφ was applied. The mixture was supplied to a machine and melted and kneaded at a processing temperature of 345 to 360°C to form pellets.

Next, the pellets were put into an injection molding machine (cylinder temperature: 350
~360℃, injection pressure 1400~1700kgf/cd
), 3.2 mm x 12.7 mm x 1
A 30 mm molded test piece was prepared. Next, this test piece was heat treated in a hot air dryer at 160° C. for 24 hours, at 240° C. for 24 hours, and at 260° C. for 48 hours, and then the water absorption was measured, and the results are shown in Table 1.

In addition, Comparative Example 2 (polyamideimide (B-1) alone)
The melt viscosity was too high, and the load on the extruder screw shaft exceeded the allowable range, making it impossible to pelletize. Therefore, we compressed the powder as it was (380℃, 1
500kgf/cal) 3.2 mm from there
A test piece measuring 12.7mm x 130mm was cut out and a water absorption test was conducted.

Table 1 clearly shows that the composition of the present invention has significantly lower hygroscopicity than the blank Comparative Example 1.

Furthermore, although the polyamide-imide (B-1) of Comparative Example 2 has low hygroscopicity, it cannot be injection molded and is not practical.

(Margins below this page) Comparative Example 3 The polyamide-imide resin powder of (A-1") was pelletized in the same manner as in Example 1, and then injection molded to create a test piece. However, because the melt viscosity was too high, , about 20-30
%, molding problems such as short shots and sprue clogging occurred, and it was found that moldability was considerably poor.

On the other hand, when the water absorption rate of the test piece was measured in the same manner as in Example 1, it was 1.03%, which was good.

Even though they are the same, there is a big difference in moldability. This clearly shows that the composition of the present invention is superior to conventional copolymerized polyamideimides.

Example 3.4 and Comparative Examples 4 to 6 After tri-blending the polyamide-imide resin powders of (A-2) and (B-1) with the composition shown in Table 2, they were pelletized and molded in the same manner as in Example 1. The water absorption rate was measured.

On the other hand, since the composition of Comparative Example 6 could not be melt-kneaded, compression molding was performed in the same manner as Comparative Example 2, and test pieces were cut out. The results are shown in Table 2, and while the composition of the present invention has both excellent low moisture absorption and moldability, the comparative examples that exceed the scope of the present invention are inferior in any of the properties. It can be seen that

(Margin below this page) Example 5.6 and Comparative Example 7.8 After tri-blending the polyamide-imide resin powders of (A-3) and (B-2) with the composition shown in Table 3, the same procedure as in Example 1 was carried out. Pelletizing and injection molding were performed using the method. On the other hand, Comparative Example 8 could not be pelletized and was compression molded in the same manner as Comparative Example 2.

The water absorption measurement results are shown in Table 3, and the composition of the present invention has
Compared to the blank Comparative Example 7, hygroscopicity is improved and injection moldability is maintained.

(Margins below this page) [Effects of the Invention] As is clear from the Examples and Comparative Examples, the composition of the present invention has improved hygroscopicity while maintaining the melt moldability of the polyamide-imide resin.

Therefore, it can be widely used in applications where dimensional changes and swelling due to moisture absorption are a problem, and is useful for, for example, automobile parts, electric/electronic equipment parts, office equipment parts, etc.

Claims (1)

[Claims] A, the main structural units are repeating units represented by general formulas (I) and (II), and the molar ratio (I/II) of (I) and (II) is 100/0 to 5. /95, and 90 to 30% by weight of a polyamide-imide resin whose main structural units are B and a repeating unit represented by general formula (III). ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (I) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (II) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (III) (In the formula, Ar is (I) and ( II) As a whole of Eq.
5 to 70 mol% ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼
95 to 30 mol% of the divalent residues are the divalent residues of ▲There are mathematical formulas, chemical formulas, tables, etc.▼, and X is the divalent residues of There are ▼ or ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, Y is a direct bond, -O-, -S-, -SO_2, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, or ▲ Numerical formulas, chemical formulas, tables, etc. etc. ▼, R_1 is a methyl group, R_2 is a carbon number of 1~
4 alkyl group, fluorine-substituted alkyl group or phenyl group, a is 0, 1 or 2, b and c are integers of 0 to 4,
x represents an integer from 1 to 500. )