JPH0565409A - Polyamide resin composition - Google Patents

Abstract

PURPOSE:To obtain a lightweight polyamide resin composition having excellent water resistance, chemical resistance, mechanical properties, fluidity in molding, strength at weld part, rigidity and low warpage deformation. CONSTITUTION:(A) 100 pts.wt. resin composition composed of A1: 30-80wt.% polyamide resin composition comprising a m-xylene group-containing polyamide resin or a polyamide resin composition consisting of the m-xylene group- containing polyamide resin and a polyamide 66 and A2: 70-20wt.% modified polyphenylene ether rein prepared by reacting an unsaturated aliphatic carboxylic acid (anhydride) is blended with (B) 5-25 pts.wt. carbon fibers, (C) 5-25 pts.wt. glass flakes and optionally (D) 1-15 pts.wt. elastic material of a hydrogenated A-B-A type block copolymer (A is polymer block of vinyl aromatic hydrocarbon; B is polymer block of conjugated diene-based hydrocarbon compound to give the objective polyamide resin composition having >=100mm bar flow length of fluidity, >=90,000kgf/cm<2> modulus in flexure, <=1.35 specific gravity and low warpage.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a polyamide resin composition comprising a polyamide resin, a polyphenylene ether resin, carbon fibers and glass flakes. For more details,
The present invention is an invention relating to a lightweight polyamide resin composition which is excellent in water resistance, chemical resistance, mechanical properties, fluidity during molding, and rigidity, has improved weld portion strength, and has little warpage deformation. ..

[0002]

2. Description of the Related Art At present, there is a demand for miniaturization and weight reduction of electronic equipment such as home electric appliances and office automation equipment. Therefore, use of plastics for these equipments is being considered. Therefore, the materials used for the electronic devices have been changed from metal to lightweight plastic. However, the currently used plastics have not achieved sufficient weight reduction, and further weight reduction is desired. Until now, ABS resin, A, which has good moldability, is inexpensive, and has a good appearance finish
Although S resins, modified polyphenylene ether resins and the like have been studied, rigidity and the like are insufficient and practically satisfactory products have not been obtained.

[0003]

The object of the present invention is to overcome the deficiencies of the known art as described above, and to provide a thin and lightweight casing material for electronic equipment, which is water resistant, chemical resistant, and fluidity during molding. Another object of the present invention is to provide a molding resin composition which is excellent in mechanical properties and rigidity, has improved weld portion strength, and has less warp deformation.

[0004]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that thin-wall molding is achieved by blending a carbon fiber and glass flakes into a resin composition comprising a specific polyamide resin and a modified polyphenylene ether resin. Even if it is a product
The present invention has been completed by finding a well-balanced molding resin composition that has excellent chemical resistance, fluidity, mechanical properties and rigidity, and has little warpage deformation during molding.

That is, the present invention comprises 30 to 80% by weight of a metaxylylene group-containing polyamide resin and 70 to 20% by weight of a modified polyphenylene ether resin obtained by reacting an unsaturated aliphatic carboxylic acid or its acid anhydride. (Here, the total weight% is 100% by weight) 100% by weight of the resin composition, 5 to 25 parts by weight of carbon fibers and 5 to 25 parts by weight of glass flakes, and a metaxylylene group-containing polyamide Resin 40-9
30 to 80% by weight of a polyamide resin mixture containing 9% by weight and 60 to 1% by weight of polyamide 66 (here, the total of the% by weight is 100% by weight), and an unsaturated aliphatic carboxylic acid or its acid anhydride 5 to 25 parts by weight of carbon fiber and glass to 100 parts by weight of a resin composition consisting of 70 to 20% by weight of a modified polyphenylene ether resin obtained by reacting a resin (here, the total of the weight% is 100% by weight) The present invention relates to a resin composition containing 5 to 25 parts by weight of flakes.

The metaxylylene group-containing polyamide resin (hereinafter sometimes referred to as MX nylon) used in the present invention comprises metaxylylenediamine alone or 60% by weight or more of metaxylylenediamine and 40% by weight or less of paraxylylenediamine. Diamine mixture and carbon number 6 to 12
Is a polyamide resin synthesized by polycondensation reaction with α, ω-linear aliphatic dibasic acid such as adipic acid, sebacic acid, suberic acid, undecanoic acid, dodecanedioic acid. Among MX nylons, adipic acid is particularly preferable as the α, ω-straight chain aliphatic dibasic acid in consideration of the balance of moldability and physical properties. Polyamide 66 used in the present invention has an effect of shortening the moldability of the present composition, that is, the cycle time at the time of molding.

The mixing ratio of polyamide 66 to MX nylon has a wide range of effects only from the viewpoint of shortening the moldability, but when the physical performance of the molding resin composition is also taken into consideration, the mixing ratio thereof. Is preferably 60 to 1% by weight of polyamide 66 with respect to 40 to 99% by weight of MX nylon (here, the total weight% is 100% by weight), and when the amount of polyamide 66 is less than this range, There is no effect on the expected shortening of the molding cycle, and when the amount is more than this range, the strength and dimensional change of the resulting composition due to water absorption are large, which causes practical inconvenience. The polyphenylene ether resin used in the present invention has the general formula

[0008]

[Chemical 1]

It has a structural unit represented by the formula (1) in its main chain and may be a homopolymer, a copolymer or a graft polymer. Specific examples of the polyphenylene ether resin include poly (2,6-dimethyl-1,4-phenylene) ether, poly (2,6-diethyl-1,4-phenylene) ether, and poly (2,6-dipropyl-1). ，
4-phenylene) ether, poly (2-methyl-6-ethyl-1,4-phenylene) ether, poly (2-methyl-6-propyl-1,4-phenylene) ether and the like can be exemplified, but poly (especially 2,6-dimethyl-1,4-
Phenylene) ether, 2,6-dimethylphenol,
A 2,3,6-trimethylphenol copolymer and a graft copolymer in which styrene is graft-polymerized are preferable.

The modified polyphenylene ether resin used in the present invention is obtained by melt-mixing a polyphenylene ether resin and an unsaturated aliphatic carboxylic acid or its acid anhydride in the absence of a catalyst, or by reacting them in the presence of a catalyst.
When an unsaturated aliphatic carboxylic acid anhydride is used for modification of the polyphenylene ether resin, without modification, by reacting the unsaturated aliphatic carboxylic acid anhydride with the polyphenylene ether resin in a molten mixed state for modification A polyphenylene ether resin can be obtained.

In this case, the melt-mixing method is not particularly limited and may be a kneader, a Banbury mixer, an extruder or the like, but an extruder is preferably used in consideration of operability and the like. Examples of the acid anhydride of the unsaturated aliphatic carboxylic acid include maleic anhydride, itaconic anhydride, citraconic anhydride, and maleic anhydride is particularly preferable. The amount of the acid anhydride used for modifying the polyphenylene ether resin is 0.01 to 10 parts by weight, preferably 0.1 to 100 parts by weight of the polyphenylene ether resin.
It is 1 to 1 part by weight. The acid anhydride is used in an amount of 0. 0 with respect to 100 parts by weight of the polyphenylene ether resin.
If the amount is less than 01 parts by weight, the effect of improving the compatibility between the polyphenylene ether resin and the mixed polyamide resin is small, and it is difficult to obtain a composition having toughness. Further, when the use ratio of the acid anhydride exceeds 10 parts by weight with respect to 100 parts by weight of the polyphenylene ether resin, the excess acid anhydride is thermally decomposed, resulting in deterioration of heat resistance and poor appearance. The above inconvenience occurs. When an unsaturated aliphatic carboxylic acid is used for modifying the polyphenylene ether resin, a radical generator such as benzoyl peroxide, dicumyl peroxide and cumene hydroperoxide can be used as a catalyst, if necessary.

The blending ratio of the modified polyphenylene ether resin to the polyamide resin mixture can be selected in a wide range, and the polyamide resin mixture 3 is preferable.
The modified polyphenylene ether resin is 70 to 20% by weight with respect to 0 to 80% by weight. Polyamide resin mixture 30
70 parts by weight of modified polyphenylene ether resin
When it exceeds the weight part, the fluidity is poor and the moldability is deteriorated. On the other hand, when the modified polyphenylene ether resin is less than 20 parts by weight with respect to 80 parts by weight of the polyamide resin mixture, the molding shrinkage rate due to the crystallinity of the polyamide resin is large, so that the warpage of the molded product cannot be sufficiently improved. Adding an elastomer to the resin composition of the present invention has the effect of further improving impact resistance.

The elastomer that can be used in the present invention is a hydrogenated block copolymer elastic body having an ABA type structure. A and B are polymer blocks, respectively, and the central block B is a conjugated block. A diene hydrocarbon compound, usually a polymer of butadiene, which is a polybutadiene block before hydrogenation, but is a block in which the double bond in polybutadiene is converted to saturated hydrocarbon by hydrogenation, Block A represents a vinyl aromatic hydrocarbon block, and is preferably a block made of polystyrene. The molecular weight of the end block A is 4,000 to 11
5,000, preferably 5,000 to 15,000, while the central block B has a molecular weight of 20,000 to 450,000, preferably 2
It is desirable to be 5,000 to 100,000.

When the hydrogenated block copolymer elastic material used in the resin composition of the present invention is compounded, the compounding amount is 1 part with respect to 100 parts by weight of the resin composition comprising the xylylene group-containing polyamide resin and the modified polyphenylene ether resin.
~ 15 parts by weight. When it is less than the above range, the effect of improving impact resistance is small, and when it exceeds the above range, the rigidity is lowered, which is not preferable.

The carbon fiber used in the present invention is not limited as long as it can be used as a reinforcing material for resin, and may be either roving or chopped strand, but the fiber length is usually 0.1 to 25 mm, Preferably 1-6
mm, and an average fiber diameter of 7 to 20 μm is desirable. If the fiber length is too long, the warpage deformation of the molded product will be large, and if it is too short, the reinforcing effect on the strength and rigidity will be poor. As the type of carbon fiber, either PAN-based carbon fiber, pitch-based carbon fiber, or any carbon fiber can be used.

The amount of carbon fiber used in the present invention is
The amount of carbon fiber is 5 to 25 parts by weight with respect to 100 parts by weight of a resin composition composed of a polyamide resin and a polyphenylene ether resin. When the amount of carbon fiber is less than 5 parts by weight with respect to 100 parts by weight of the resin composition, the reinforcing effect on strength and rigidity cannot be obtained. If the amount of carbon fiber is more than 25 parts by weight based on 100 parts by weight of the above resin composition, the production of the composition will be hindered and the fluidity at the time of injection molding will decrease, resulting in a thin-walled molded product. Molding becomes difficult.

The glass flakes used in the present invention have the effect of preventing warpage deformation of the molded product and improving the strength of the welded portion, because the glass flakes have a flaky scale shape.
It is also effective for increasing the rigidity of the material composition. The average particle size of the glass flakes used in the present invention is 300
It is not more than μm, preferably not more than 150 μm. When the average particle diameter is 150 μm or less, the one having excellent surface smoothness can be obtained. The glass flakes used in the present invention may be those without surface treatment, or may be those surface-treated with a coupling agent such as a silane coupling agent or a titanate coupling agent. Those treated with a coupling agent are preferred.

The blending ratio of the glass flakes used in the present invention is 5 to 2 with respect to 100 parts by weight of a resin composition comprising a polyamide resin and a modified polyphenylene ether resin.
5 parts by weight. When the amount of glass flakes is less than 5 parts by weight with respect to 100 parts by weight of the resin composition, the effect of improving the rigidity cannot be obtained and the effect of preventing warpage cannot be obtained. Further, when the content of glass flakes exceeds 25 parts by weight with respect to 100 parts by weight of the above resin composition, the specific gravity of the composition becomes high, or the fluidity at the time of injection molding is reduced, resulting in a thin wall. Molding of molded products becomes difficult.

The specific gravity of the resin composition of the present invention is 1.35 or less, preferably 1.30 or less.
The main purpose of the resin composition of the present invention is to reduce the weight of electronic equipment. If the specific gravity exceeds 1.35, the weight of the product will increase and it may be impractical. The flexural modulus of the molded product obtained by molding the polyamide resin composition of the present invention is 90,000 kgf.
/ Cm ² or more, preferably 120,000 kgf / cm ² or more. If the flexural modulus is less than 90,000 kgf / cm ² , the molded product may be largely deflected under a load, which may make it difficult to obtain a thin molded product.

The fluidity of the resin composition of the present invention has a depth of 1 m.
m, width 20mm cavity, resin temperature 280
The value measured at a mold temperature of 130 ° C and a mold length of 1 is a flow length of 1
00 mm or more, preferably 120 mm or more is desirable.
If the flow length is less than 100 mm, defective filling or poor appearance of the molded product may occur, and it may be difficult to mold the desired thin and lightweight molded product. Further, whiskers such as glass fiber, potassium titanate fiber and zinc oxide can be added to the polyamide resin composition of the present invention, but since the specific gravity of the resin composition increases, the allowable amount of the addition is It is preferably 10% by weight or less in the polyamide resin composition of the invention.

Further, the resin composition of the present invention may optionally contain various additives used in polymer materials such as stabilizers, dyes / pigments, release agents, lubricants and fillers. You can do it. The resin composition of the present invention can be produced by a method of melt-kneading using an ordinary single-screw or twin-screw extruder.

[0022]

By using the polyamide resin composition of the present invention, it is possible to reduce the size and weight of electronic equipment such as home electric appliances and office automation equipment.

[0023]

EXAMPLES The present invention will be specifically described below with reference to examples. In the examples, "parts" means "parts by weight" unless otherwise specified. Examples 1 to 4 and Comparative Examples 3 to 5
Injection molding conditions are: resin temperature 280 ° C., mold temperature 130
° C., and the injection pressure 1100 kgf / cm ^2. In addition, Comparative Examples 1 to
The injection molding conditions for No. 2 are: resin temperature 220 ° C, mold temperature 50
° C., and the injection pressure 1100 kgf / cm ^2.

The evaluation was carried out by the following method. Specific gravity: ASTM D792 Bending strength: ASTM D790 Bending elastic modulus: ASTM D790 Isot impact strength: ASTM D256 (1/4 inch, with notch) Heat distortion temperature: ASTM D648 Flow length: Flowability (bar-flow length) Width 20 mm,
Using a mold (temperature: 130 ° C.) having a flow path with a depth of 1 mm, in Examples 1 to 4 and Comparative Examples 3 to 4, the resin temperature was 2
Molded under the conditions of 80 ℃, injection pressure 1100kgf / cm2,
In Comparative Examples 1 and 2, the resin temperature is 220 ° C. and the injection pressure is 110.
It was measured under the condition of 0 kgf / cm ² .

Formability: Dimensions are 90 × 90 × 1 mm
And a circular plate having a diameter of 4 "and a thickness of 1/16" were molded, and the moldability thereof was evaluated. The indications of fluidity in the evaluation results of moldability in Tables 1 and 2 are as follows. Good: The fluidity at the time of molding was good, and it was possible to mold a square plate and a circular plate. No; the fluidity at the time of molding was poor, and it was impossible to mold a square plate and a circular plate. No .: 24 hours after forming the square plate and the circular plate, the flatness of the molded product was measured using a three-dimensional measuring machine.

Example 1 Intrinsic viscosity 0.45d measured in chloroform at 25 ° C.
L / g of polyphenylene ether (hereinafter sometimes referred to as PPE) 5 kg was added to 25 g of maleic anhydride, and the mixture was mixed with a super mixer for 3 minutes, and then kneaded under heating and melting with a twin-screw extruder to obtain maleic anhydride. Modified PPE
(Hereinafter sometimes referred to as modified PPE) was obtained. Modified P
50 parts of PE, 50 parts of polymethaxylylene adipamide having a number average molecular weight of 16,000 (hereinafter referred to as nylon MXD6) obtained by polycondensation from metaxylylenediamine and adipic acid, carbon fiber (average diameter of fiber: 10 μm, 10 parts of chop (average length: 6 mm) and 10 parts of glass flakes (at least 70% of which have an average particle size of 300 μm or less, aminosilane-treated) were dry-blended with a tumbler and then melted with an extruder set at 285 ° C. The mixture was mixed to obtain a resin composition. The obtained resin composition was molded into a test piece specified by ASTM with an injection molding machine. The compounding composition and the evaluation results are summarized in Table 1.

Example 2 In producing the maleic acid-modified PPE described in Example 1,
Polystyrene, ethylene, butylene type block copolymer as rubber component for 45 parts of PPE (manufactured by Shell Chemical,
A rubber-containing maleic anhydride-modified PPE was obtained by blending 5 parts of trade name: Kraton G1650). A resin composition was obtained in the same manner as in Example 1 except that this rubber-containing maleic anhydride-modified PPE and polyamide 66 were used. The obtained resin composition is AS-molded with an injection molding machine.
A test piece specified by TM was molded. The evaluation results are shown in Table 1.

Examples 3 and 4 Maleic anhydride modified PP similar to that used in Example 2
E, nylon MXD6, polyamide 66, carbon fiber and glass flakes were placed in a tumbler in a weight ratio shown in Table 1 and dry-blended, and then a resin composition was obtained in the same manner as in Example 1. The obtained resin composition with an injection molding machine,
A test piece specified in ASTM was molded. Table 1 shows the evaluation results of the test pieces. In Examples 1 to 4 described above, the moldability was good, the flexural modulus was high, and the warpage at the time of molding was also good, which was practically satisfactory.

Comparative Example 1 In the same manner as in Example 1, a test piece of ABS resin (medium impact grade) alone was prepared and evaluated.
The results are shown in Table 2. In this comparative example, the moldability and the warp were good, but the elastic modulus was low. Comparative Example 2 A test piece was prepared in the same manner as in Example 1, using a resin composition prepared by mixing 100 parts of ABS resin (medium impact grade) with 20 parts of the same carbon fiber as used in Example 1. The evaluation results are shown in Table 2. In this comparative example, the flowability was poor and it was impossible to form a square plate.

Comparative Example 3 Nylon MXD6 similar to that used in Example 1, modified P
Using PE, carbon fiber, and glass flakes, with the compounding ratios shown in Table 2, a test piece was prepared in the same manner as in Example 1 and evaluated. The results are shown in Table 2. In this comparative example, the flowability was poor and the thick square plate could not be formed.

Comparative Example 4 Nylon MXD6 100 similar to that used in Example 1
Part and 15 parts of carbon fiber, a test piece was prepared and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2. In Comparative Example 1, the flexural modulus was low, in Comparative Examples 2 and 3, the moldability was poor, and in Comparative Example 4, the warpage of the molded product was large, and neither was practical.

[Table 1]

[Table 2]

Claims (6)

[Claims] 1. A polyamide resin containing a metaxylylene group 3
It is composed of 0 to 80% by weight and 70 to 20% by weight of a modified polyphenylene ether resin obtained by reacting an unsaturated aliphatic carboxylic acid or an acid anhydride thereof (here, the total of the% by weight is 100% by weight). ) 100 parts by weight of the resin composition, 5 to 25 parts by weight of carbon fibers and 5 parts of glass flakes
A polyamide resin composition containing about 25 parts by weight. 2. A polyamide resin containing a metaxylylene group 3
It is composed of 0 to 80% by weight and 70 to 20% by weight of a modified polyphenylene ether resin obtained by reacting an unsaturated aliphatic carboxylic acid or an acid anhydride thereof (here, the total of the% by weight is 100% by weight). ) In 100 parts by weight of the resin composition, a hydrogenated A-B-A type block copolymer elastic body (wherein A represents a vinyl aromatic hydrocarbon polymer block and B represents a conjugated diene hydrocarbon compound polymer block). ) 1
.About.15 parts by weight, carbon fibers 5 to 25 parts by weight, and glass flakes 5 to 25 parts by weight. 3. The polyamide resin composition according to claim 1 or 2, wherein the resin composition has a flow length of 100 mm or more (a cavity having a depth of 1 mm and a width of 20 mm is used, Resin temperature 280 ℃, mold temperature 130
(Value measured at 0 ° C.), the molded product obtained from the resin composition has a flexural modulus of 90,000 kgf / cm ² or more, a specific gravity of 1.35 or less, and a small amount of warpage. Resin composition. 4. A metaxylylene group-containing polyamide resin 4
Polyamide 66 was added to 0 to 99% by weight of 60 to 1% by weight (here, the total of the% by weight is 100% by weight).
It comprises 30 to 80% by weight of a polyamide resin mixture and 70 to 20% by weight of a modified polyphenylene ether resin obtained by reacting an unsaturated aliphatic carboxylic acid or an acid anhydride thereof (where the total of the% by weight is 100% by weight). %) 5 to 25 parts by weight of carbon fibers and 5 to 25 parts by weight of glass flakes are mixed with 100 parts by weight of the resin composition. 5. A metaxylylene group-containing polyamide resin 4
Polyamide 66 was added to 0 to 99% by weight of 60 to 1% by weight (here, the total of the% by weight is 100% by weight).
It comprises 30 to 80% by weight of a polyamide resin mixture and 70 to 20% by weight of a modified polyphenylene ether resin obtained by reacting an unsaturated aliphatic carboxylic acid or an acid anhydride thereof (where the total of the% by weight is 100% by weight). %) To 100 parts by weight of a resin composition, and a hydrogenated ABA type block copolymer elastic body (where A is a vinyl aromatic hydrocarbon polymer block and B is a conjugated diene hydrocarbon compound polymer). 1 to 15 parts by weight, carbon fiber 5 to 5)
A polyamide resin composition containing 25 parts by weight and 5 to 25 parts by weight of glass flakes. 6. The polyamide resin composition according to claim 4 or 5, wherein the resin composition has a flowability of 100 mm or more in a bar-flow length (using a cavity having a depth of 1 mm and a width of 20 mm). Temperature 280 ℃, mold temperature 130 ℃
Polyamide characterized in that the molded product obtained from the resin composition has a flexural modulus of 90,000 kgf / cm ² or more, a specific gravity of 1.35 or less, and less warpage. Resin composition.