JPH0794602B2 - Polyamide resin composition and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Technical Field) The present invention is characterized by adding an aliphatic polyamide, a crystalline aromatic ring-containing polyamide, an aromatic polyether resin, an acid anhydride group and / or a carboxylic acid group. Styrene-based modified thermoplastic elastomer, or a compound having a carbon-carbon double bond and an acid anhydride group and / or a carboxylic acid group in the molecule and a thermoplastic elastomer, which has small physical dependence on water absorption, especially flexural modulus Little decrease due to water absorption,
The present invention relates to a polyamide resin composition having excellent properties in heat resistance, mechanical properties, impact resistance, and chemical resistance. Molded articles using the polyamide resin composition of the present invention, especially connectors, are mainly used in the fields of automobiles and electric / electronic fields.

(Prior Art and Problems Thereof) Polyamide resins have been used as so-called engine nearing resins in the fields of automobiles and electric / electronic fields. Above all, nylon 66 has been widely used because of its well-balanced physical properties, especially toughness and high heat resistance. However, nylon 66 has a large practical drawback that it has a large water absorption property and its physical properties and dimensions are highly dependent on water absorption. In particular, in the case of connectors for automobiles, the bending elastic modulus significantly decreases when absorbing water compared to when it is absolutely dry, which causes the insertion force when mounting the connector to fluctuate greatly in winter with low humidity and rainy season with high humidity. Next to
Eventually, this was a big problem that could lead to mounting mistakes.

The present inventors have conducted extensive studies in order to improve the above-mentioned problems, and found that a composition comprising an aromatic ring-containing polyamide having crystallinity and a thermoplastic elastomer can significantly suppress changes in physical properties due to water absorption. I filed a patent application first. However, this polyamide resin composition does not have a sufficient heat distortion temperature when molded at a mold temperature of 80 ° C. suitable for molding nylon 66, and when used in a high temperature atmosphere such as underhood parts of automobiles, The shape retention property of the parts was a problem.

As a composition related to the present invention, a composition comprising an aromatic ring-containing polyamide having crystallinity, an aliphatic polyamide and an inorganic reinforcing material is disclosed in JP-A-58-120665, JP-A-58-3875.
No. 1 discloses a composition comprising a thermoplastic semi-crystalline polyamide, an amorphous aromatic ring-containing thermoplastic polyamide and a toughening agent. However, all of the above-mentioned compositions had a problem in the heat distortion temperature when they were molded in a mold at 80 ° C. Further, Japanese Patent Publication No. 59-41663 discloses a composition comprising an aromatic polyether resin and a polyamide. In these compositions, (i) there is little decrease in rigidity due to water absorption, and (ii) 80 ° C. It has not been possible to satisfy both of the two requirements that the heat distortion temperature is high when molding with a mold at the same time.

(Means and Actions for Solving Problems) The present inventors have excellent physical properties of nylon 66, that is,
It has mechanical strength, impact resistance, chemical resistance, and good moldability, and has a high retention rate such as bending elastic modulus against moisture absorption and dryness, and when molded at a mold temperature of 80 ° C. As a result of further investigation of a molding resin composition having a high heat distortion temperature, as a result, (A) a specific amount of an aliphatic polyamide, (B) a specific amount of a polyamide obtained by polymerization using a specific amount of terephthalic acid and isophthalic acid (C ) A specific amount of aromatic polyether resin,
(D) A specific amount of styrene-modified thermoplastic elastomer having an acid anhydride group and / or carboxylic acid group added thereto, or (E) having a carbon-carbon double bond and an acid anhydride group and / or carboxylic acid group in the molecule. It was found that a polyamide resin composition comprising a compound and (F) a specific amount of elastomer can satisfy the above-mentioned objects, and further, the moldability can be remarkably improved as compared with the composition previously applied, and arrived at the present invention. It is a thing.

The resin composition (a) comprising the aliphatic polyamide, the aromatic ring-containing polyamide having crystallinity, and the aromatic polyether resin of the present invention is a composition comprising an aromatic polyamide having crystallinity and a thermoplastic elastomer, and an aliphatic compound. Compared with a composition comprising polyamide and an aromatic ring-containing polyamide having crystallinity, an aliphatic polyamide, a composition containing an amorphous aromatic ring-containing polyamide and an elastomer, the heat distortion temperature when molded by a mold at 80 ° C. is higher. In addition, compared with a composition comprising an aromatic polyether resin and an aliphatic or aromatic ring-containing polyamide, (i) less reduction in rigidity due to water absorption,
i) High heat distortion temperature when molded with 80 ° C mold,
Both requirements can be satisfied at the same time. This can be achieved for the first time by blending an aliphatic polyamide, an aromatic ring-containing polyamide and an aromatic polyether resin with a specific composition. Furthermore, this aliphatic polyamide,
By blending both a specific amount of a styrene-based modified thermoplastic elastomer and a specific amount of an elastomer into a resin composition (a) comprising a crystalline aromatic ring-containing polyamide and an aromatic polyether-based resin, only one of them is added. It was found that not only the impact resistance is improved but also the moldability is remarkably improved as compared with the case of blending the compound No.

The present invention comprises (A) 10 to 60% by weight of an aliphatic polyamide obtained from an aliphatic diami and an aliphatic dicarboxylic acid, (B)
A diamine containing an aromatic ring and / or terephthalic acid and isophthalic acid are contained in 1 mol of the polyamide-forming monomer.
A polyamide obtained by polymerizing a polyamide-forming monomer contained in 0.5 to 0.5 mol, wherein the polyamide has a melting point of 250 to 300 ° C., and the melting heat amount at the melting point is 2 cal.
100 parts by weight of a resin composition (A) consisting of 10 to 50% by weight of polyamide / gr or more and 10 to 70% by weight of (C) aromatic polyether resin, and (D) acid anhydride group and / or carvone A styrene-modified thermoplastic elastomer having an acid group added thereto, or a compound (E) having a carbon-carbon double bond and an acid anhydride group and / or a carboxylic acid group in the molecule.
A polyamide resin composition comprising 1 to 30 parts by weight of (F) an elastomer and 3 to 50 parts by weight of an elastomer, and (C) an aromatic polyether resin and (D) a styrene-modified thermoplastic resin for preparing the composition. Provided is a method for producing a polyamide resin composition, which comprises melt-mixing an elastomer.

The aliphatic polyamide (A) of the present invention can be produced by first forming a salt from an aliphatic diamine and an aliphatic dicarboxylic acid, and heating this under pressure to carry out condensation polymerization. Specifically, polyamide 6/6, polyamide 6/1
0, polyamide 6/12, polyamide 4/6, etc.,
It may be a mixture or copolymer of these.
Polyamide 6/6 and polyamide 4/6 are particularly preferable.

The compounding amount is 10 to 60% by weight per resin composition (a),
It is preferably 20 to 40% by weight. If it is less than 10% by weight, the heat distortion temperature is lowered and the moldability becomes poor. On the other hand, 60% by weight
If it exceeds, the flexural modulus at the time of water absorption is significantly reduced.

The polyamide (B) of the present invention is composed of terephthalic acid and isophthalic acid in an amount of 0.4 to 0.5 mol based on 1 mol of all diamines, all carboxylic acids and all aminocarboxylic acids. Terephthalic acid and isophthalic acid components are 0.4
If it is less than the molar amount, the water absorption dependency of the physical properties of the obtained polyamide will not be sufficiently reduced. On the other hand, if it exceeds 0.5 mol, the viscosity at the time of melting becomes high, and good moldability cannot be obtained. Further, the polyamide is a polymer having a melting point of 250 to 300 ° C. measured using a differential thermal analyzer and a heat of fusion calculated from the area of the melting peak of 2 cal / gr or more. If the melting point is lower than 250 ° C, the heat resistance will be insufficient, and if it is higher than 300 ° C, the moldability will be poor. The preferred melting range is 25
0 to 290 ° C.

If the heat of fusion is less than 2 cal / gr, the polymer will be amorphous and the chemical resistance will be particularly poor.

As the polyamide-forming monomer other than terephthalic acid and isophthalic acid used in the present invention, γ-aminobenzoic acid, diaminobutane, hexamethylenediamine, 2-
Methyldiaminobutane, 2-methylpentamethylenediamine, 2,5-dimethylhexamethylenediamine, adipic acid, sebacic acid, dodecanedioic acid, etc. may be used alone or in combination so as not to impair the melting point and the range of heat of fusion. Can be used.

More specifically, when terephthalic acid or isophthalic acid is used as the (B) polyamide of the present invention, the amounts of terephthalic acid and isophthalic acid are all polyamide-forming monomers 1.
It is preferably 0.4 to 0.5 mol, and the molar ratio of terephthalic acid / isophthalic acid is preferably in the range of 4/6 to 6/4. The molar ratio of 4.5 / 5.5 to 5.5 / 4.5 is particularly excellent in mechanical properties and chemical resistance. The diamine component can be obtained by using, for example, hexamethylenediamine and / or metaxylylenediamine.

The (B) polyamide of the present invention may have any molecular weight so long as it can be molded, but the sulfuric acid viscosity ηr is preferably 1.6 or more. When ηr is 1.6 or more, a decrease in Izod impact strength after hot water treatment, which is considered to be an accelerated test of an aging test in a high temperature atmosphere during water absorption, is suppressed.

The (B) polyamide used in the present invention can be obtained by a known method. For example, it can be produced by forming a salt with a dicarboxylic acid and a diamine, which are constituent components of the polyamide, and heating under pressure to cause condensation polymerization.

The compounding amount is 10 to 50% by weight based on the resin composition (a),
It is preferably 20 to 35% by weight. If it is less than 10% by weight, the flexural modulus of water is not sufficiently retained when it is absorbed in water and dried. On the other hand, when it exceeds 50% by weight, the heat distortion temperature becomes low,
Moldability is also poor.

The (C) aromatic polyether resin of the present invention has the general formula Is a repeating unit, and the constitutional unit is a homopolymer or copolymer of (I) or (I) and (II), and a graft copolymer obtained by graft-polymerizing styrene or the like to the polymer. It refers to a polymer.

Typical examples of polyphenylene ether homopolymers include poly (2,6-dimethyl-1,4-phenylene) ether, poly (2-methyl-6-ethyl-1,4-phenylene) ether, poly ( 2,6-diethyl-1,4-phenylene) ether, poly (2-ethyl-6-n-propyl-)
1,4-phenylene) ether, poly (2,6-di-n-propyl-1,4-phenylene) ether, poly (2-methyl-6-n-butyl-1,4-phenylene) ether, poly ( 2-methyl-6-isopropyl-1,4-phenylene)
Ether, poly (2-methyl-6-chloro-1,4-phenylene) ether, poly (2-methyl-6-hydroxyethyl-1,4-phenylene) ether, poly (2-methyl-6-chloroethyl-1) Homopolymers such as 4,4-phenylene) ether may be mentioned.

Polyphenylene ether copolymer is orthocresol or general formula And a polyphenylene ether copolymer mainly composed of a polyphenylene ether structure obtained by copolymerization with an alkyl-substituted phenol such as 2,3,6-trimethylphenol.

Further, 50 to 100% by weight of the above polyphenylene ether may be used, which is obtained by graft copolymerizing styrene alone or 50 to 0% by weight of a monomer copolymerizable with styrene. If the styrene component exceeds 50% by weight, the heat distortion temperature decreases.

The compounding amount of the aromatic polyether resin (C) is 10 to 70% by weight, preferably 20 to 45% by weight, based on the resin composition (a). If it is less than 10% by weight, the heat distortion temperature will be low. On the other hand, if it exceeds 70% by weight, it becomes brittle and the moldability becomes poor.

The styrene-modified thermoplastic elastomer (D) to which an acid anhydride group and / or a carboxylic acid group is added according to the present invention is a known styrene-based thermoplastic elastomer, preferably vinyl aromatic compound block (a) and olefin compound polymer ( b) or a block copolymer consisting of a vinyl aromatic compound block (a) and an olefinic compound (b), wherein the unsaturation of the block (b) exceeds 20%. This is a block copolymer obtained by adding an acid anhydride group or a carboxylic acid group.

Specific examples of the compound having a carbon-carbon double bond and an acid anhydride group and / or a carboxylic acid group in the molecule (E) of the present invention include maleic anhydride, dichloromaleic anhydride, tetraconic anhydride, acrylic acid and methacrylic acid. Acid, crotonic acid, etc. are mentioned. Maleic anhydride is particularly preferable.

The compounding amount of (D) a styrene-based modified thermoplastic elastomer or (E) a compound having a carbon-carbon double bond and an acid anhydride group and / or a carboxylic acid group in the molecule is 100 parts by weight of the resin composition (a). , 0.1 to 30 parts by weight, preferably 0.5
~ 20 parts by weight. If it is less than 0.1 part by weight, the effect of improving impact resistance is not sufficient, and if it exceeds 30 parts by weight, mechanical strength is lowered.

Impact resistance by blending both (F) elastomer and (D) styrene-based modified thermoplastic elastomer or (E) compound having carbon-carbon double bond and acid anhydride group and / or carboxylic acid group in molecule And moldability are greatly improved. Further, the peeling phenomenon during molding is also improved. The reason for this is not clear, but it is presumed that it is because the compatibility between the polyamide and the aromatic polyether resin is improved.

The (F) elastomer of the present invention is a known elastomer having a better compatibility with polyamide than the (C) aromatic polyether resin, preferably an olefin elastomer such as ethylene propylene rubber, and particularly preferably an ionomer. The ionomer of the present invention is a copolymer composed of an ethylenically unsaturated carboxylic acid alkyl ester, an unsaturated carboxylic acid and an unsaturated carboxylic acid metal salt, the proportion of ethylene is 90 to 98 mol%, Between the unsaturated carboxylic acid alkyl ester, the unsaturated carboxylic acid, and the unsaturated carboxylic acid metal salt which occupy 10 to 2 mol%, when the respective molar numbers in the copolymer are a, b and c, And an ionomer which is an ethylene-based copolymer having the following relationship.

The compounding amount is 3 to 50 parts by weight, preferably 5 to 30 parts by weight, per 100 parts by weight of the resin composition (a). If it is less than 3 parts by weight, the impact resistance is low. On the other hand, if it exceeds 50 parts by weight, the mechanical strength will decrease.

The polyamide resin composition of the present invention can be obtained by a usual method. For example, (A) aliphatic polyamide, (B)
Aromatic ring-containing polyamide having crystallinity, (C) aromatic polyether resin, (D) styrene modified thermoplastic elastomer, or (E) carbon-carbon double bond and acid anhydride group and / or carvone in the molecule. It can be obtained by melt-kneading the compound having an acid group and the (F) elastomer using an ordinary two-phase extruder or the like. At this time, when the (D) styrene-based modified thermoplastic elastomer is used as the compatibilizer, the (C) aromatic polyether-based resin and (D) styrene-based modified thermoplastic elastomer are preliminarily used in a usual twin-screw extruder or the like. When melt-kneaded and used, a polyamide resin composition excellent in impact resistance, heat distortion temperature and the like can be obtained.

Although the polyamide resin composition of the present invention has been described above in detail, other resin polymers, colorants, nucleating agents, oxidative deterioration preventing agents, heat stabilizers, and the like may be added to these compositions in a range that does not impair the object of the present invention. An ultraviolet absorber, a lubricant, a plasticizer, a release agent, a flame retardant, an inorganic reinforcing material and the like can be added according to the purpose.

(Examples) Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

The physical properties of polymers and the physical properties of molded articles in each example were measured and the moldability was determined as follows.

(1) Polymer physical properties Melting point, heat of fusion Using a differential scanning calorimeter (PERKIN-ELMER: DSC-1B type), the temperature was measured at a heating rate of 16 ° C / min under N ₂ atmosphere, and the peak temperature of the endothermic peak was measured. Was read as the melting point. The heat of fusion was calculated from the area of the endothermic peak.

ηr (Sulfuric acid relative viscosity) 0.25 g of a polymer was dissolved in 25 ml of 95% concentrated sulfuric acid, and the relative viscosity was measured under a constant temperature condition of 25 ° C.

(2) Molded piece The physical properties described below were measured. DRY is the value measured immediately after molding after storing the molded piece in a desiccator for 24 hours in a thermostatic chamber at 23 ° C, and WET is the molded piece. 80 ℃
Is a value measured after being immersed in hot water for 8 hours, then immersed in water at 23 ° C. for 16 hours, then allowed to stand in a constant temperature and humidity chamber at 23 ° C. and a relative humidity of 50% for 48 hours.

Tensile strength Measured according to ASTM-D-638.

Bending property Measured according to ASTM-D-790. The flexural modulus and the retention rate (%) here are the percentages of WET during DRY.

Izod impact strength (with notch) Measured according to ASTM-D-256.

Moisture content (%) Obtained from the change in weight of the molded piece with respect to DRY during WET.

Heat distortion temperature (load: 46 kg / cm ² ) It was measured according to ASTM-D-648.

(3) Moldability A test piece for evaluating physical properties was judged by releasability during molding.

The (B) crystalline aromatic ring-containing polymer used in each example and comparative example was produced as follows.

32.2 kg of terephthalic acid, 32.2 kg of isophthalic acid, and 45 kg and 109.4 kg of hexamethylenediamine were fed to a preheated reactor, and salt formation and concentration were carried out at 120 ° C. for 5 hours. The obtained concentrated liquid was kept at 230 ° C. 400
It was supplied to an autoclave and heated to 310 ° C under pressure.
At this time, the maximum pressure was adjusted to 18 kg / cm ² . 310
After reacting at 18 ° C / cm ² for 2 hours, the pressure was lowered, discharged from the autoclave, cooled, solidified, and pelletized.

As a result of measuring the melting point, the heat of fusion and ηr of the obtained polyamide, the melting point was 289 ° C., the heat of fusion 3 cal / gr and ηr 1.46.

60 kg of the thus obtained polyamide was subjected to solid phase polymerization for 15 hours at 220 ° C. with N ₂ flowing at 50 / min in a 300 tumbler type solid phase polymerization apparatus. As a result of measuring ηr of the obtained polyamide, ηr was 1.70.

Hereinafter, the polymer thus obtained is abbreviated as 6 / (T / I).

Example 1 Nylon 66 (hereinafter abbreviated as Ny66. ((Asahi Kasei Rheo
Na 1300)) 3kg, 6 / (T / I) 3kg, ηsp / C = 0.64 (chloro
(Measured in form solution) poly (2,6-dimethyl-1,4-phenyl)
Nylene) ether (hereinafter abbreviated as PPE) ((Asahi Kasei
)) 4kg, Lactone G as elastomer (Hereinafter referred to as HTR
Abbreviation) ((Ciel)) 0.6 kg, HTR 1.0 PHR anhydrous male
Styrene-based modified thermoplastic elastomer with addition of in-acid
-After blending 1.2 kg (hereinafter abbreviated as m HTR), 30
Extruded and granulated at a temperature of 300 ° C using a mmφ twin screw extruder.
An amide resin composition was obtained. Obtained polyamide resin composition
The physical properties of the product are tested at 290 ° C and 80 ° C using an injection molding machine.
It was molded into a test model piece and various physical properties were measured. The result is
The results are shown in Table 1.

Example 2 An ionomer (hereinafter abbreviated as IR) as an elastomer
((Mitsui Deyupon High Miran 1855)), Toughprene
(Made by Asahi Kasei) 1.0PHR maleic anhydride added
Styrene-based modified thermoplastic (hereinafter abbreviated as mTR)
In the same manner as in Example 1 except that it was used as a hydrophilic elastomer.
Various physical properties were measured. The results are shown in Table 1.

Example 3 8 kg of PPE and 2.4 kg of mTR were extruded and granulated by a 30 mm twin-screw extruder at a temperature of 300 ° C. 5.2 kg.Ny66 3 kg, 6 /
Various physical properties were measured in the same manner as in Example 1 except that (T / I) 3 kg and IR 0.6 kg were used. The results are shown in Table 1.

Example 4 Pellet prepared by extruding 4 kg of PPE and 1.2 kg of mTR in advance 2.
Various physical properties were measured in the same manner as in Example 3 except that 6 kg, Ny66 6 kg, 6 / (T / I) 2 kg, and IR 0.6 kg were used. The results are shown in Table 1.

Example 5 PPE (10 kg) and mTR (2.6 kg) were extruded and granulated in advance.
Various physical properties were measured in the same manner as in Example 3 except that 6.3 kg, Ny66 3 kg, 6 / (T / I) 2 kg, and IR 1.3 kg were used. First result
Shown in the table.

Comparative Example 1 Example 1 except that mHTR was 0 part by weight and HTR was 18 parts by weight.
Various physical properties were measured in the same manner as in. The results are shown in Table 1.

Comparative Example 2 Various physical properties were measured in the same manner as in Example 1 except that mHTR and HTR were not added. The results are shown in Table 1.

Comparative Example 3 Various physical properties were measured in the same manner as in Example 1 except that 3 kg of Ny66, 7 kg of 6 / (T / I), and 1.8 kg of IR were used as the composition. The results are shown in Table 1.

Comparative Example 4 Various physical properties were measured in the same manner as in Example 1 except that 6 / (T / I) 10 kg and IR 1.8 kg were used as the composition.

Comparative Example 5 Ny66 (Asahi Kasei Kogyo, Leona 1402S) injection molding machine
Molded into a molded product for physical property testing at a temperature of 275 ° C
Was measured. The results are shown in Table 1.

(Effect of the invention) The polyamide resin composition of the present invention has a small dependence of physical properties on water absorption, and in particular, has a small decrease in bending elastic modulus due to water absorption, and has excellent properties in mechanical strength and impact resistance,
Further, since it has excellent heat resistance, it can be preferably used as a molding material for parts used in the fields of automobiles and electric / electronic fields, especially for connectors.

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Claims (2)

[Claims] (1) 10 to 60% by weight of an aliphatic polyamide obtained from (A) an aliphatic diamine and an aliphatic dicarboxylic acid, and (B) 1 mole of a polyamide-forming monomer, terephthalic acid and isophthalic acid are contained. A polyamide obtained by polymerizing a polyamide-forming monomer contained in 0.4 to 0.5 mol, wherein the polyamide has a melting point of 250 to 300 ° C., and the amount of heat of fusion at the melting point is 2 cal / gr or more and has a crystalline aroma. 100 parts by weight of a resin composition (a) consisting of 10 to 50% by weight of a cyclic polyamide and 10 to 70% by weight of (C) an aromatic polyether resin, and (2) (D) an acid anhydride group and / or a carboxylic acid. 0.1 to 30 parts by weight of a styrene-modified thermoplastic elastomer having a group added thereto or (E) a compound having a carbon-carbon double bond and an acid anhydride group and / or a carboxylic acid group in the molecule, (3) (F ) D Polyamide resin composition comprising a Sutoma 3-50 parts by weight. 2. (1) 10 to 60% by weight of an aliphatic polyamide obtained from (A) an aliphatic diamine and an aliphatic dicarboxylic acid, and (B) 1 mol of a polyamide-forming monomer contains terephthalic acid and isophthalic acid. A polyamide obtained by polymerizing a polyamide-forming monomer contained in 0.4 to 0.5 mol, wherein the polyamide has a melting point of 250 to 300 ° C., and the amount of heat of fusion at the melting point is 2 cal / gr or more and has a crystalline aroma. 100 parts by weight of a resin composition (a) consisting of 10 to 50% by weight of a cyclic polyamide and 10 to 70% by weight of (C) an aromatic polyether resin, and (2) (D) an acid anhydride group and / or a carboxylic acid. 0.1 to 30 parts by weight of a styrene-modified thermoplastic elastomer having a group added thereto or (E) a compound having a carbon-carbon double bond and an acid anhydride group and / or a carboxylic acid group in the molecule, (3) (F ) D In producing the polyamide resin composition comprising a Sutoma 3-50 parts by weight,
A method for producing a polyamide resin composition, characterized in that the (C) aromatic polyether resin and (D) styrene-modified thermoplastic elastomer are melt-mixed in advance.