JP2746276B2 - Polyamide resin composition and use thereof - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a polyamide resin composition which retains inherent properties of polyamide, such as mechanical strength and heat resistance, and which is excellent in biodegradability, and a polyamide resin composition comprising the same. The present invention relates to a stretch molded article using the product.

TECHNICAL BACKGROUND OF THE INVENTION Polyamides, especially polycapramid (nylon 6) and polyhexamethylene adipamide (nylon 66) have excellent properties such as mechanical strength and heat resistance, and are widely used in applications such as films, fibers and molding materials. Have been. However, with an increase in the amount of polyamide molded articles used, polyamide molded articles after use have been left in large quantities without being incinerated. In addition, the conventional polyamide molded article has a very low biodegradability, and the polyamide molded article left in the natural world stops its shape without being decomposed for a long period of time, thus causing a problem of causing environmental pollution.

By the way, it is known that a copolyamide containing ε-caproate, which is a known substance, as a polymerization component has biodegradability and is decomposed by an enzyme such as lipase. However, copolyamide alone using ε-caproate as a polymerization component is inferior in mechanical strength, heat resistance, and economic efficiency.
It has been difficult to put a stretch molded article produced from a copolyamide containing ε-caproate as a polymerization component into practical use.

The present inventors have studied vigorously to obtain a polyamide resin composition and a stretched molded article having excellent biodegradability while retaining properties such as mechanical strength and heat resistance inherently possessed by polyamide. When a composition was obtained by blending with a copolyamide, a stretch molded article excellent in biodegradability was obtained from the composition, while maintaining properties inherent in polyamide such as mechanical strength and heat resistance. And found that the present invention was completed.

In JP-A-54-119594, a copolymer in which many ester blocks A composed of a low-molecular-weight aliphatic polyester and amide blocks B composed of a low-molecular-weight aliphatic polyamide are alternately bonded is formed. A biodegradable film is disclosed. The above ester block A is represented by the following general formula.

In the formula, X is an aliphatic ester residue having a structure in which an aliphatic alcohol and an aliphatic carboxylic acid are ester-bonded, and represented by the general formula -R ₁ OOCR ₂ -or R _3- (wherein, R ₁ is a group having 2 carbon atoms. 20 alkylene group, an ester R ₂ is an alkylene group of 0-12 carbon atoms, R ₃ is represented by an alkylene group having 1 to 5 carbon atoms.), n is contained in the polyester amide copolymer It is an average degree of polymerization of the block and is not particularly limited, but is usually an integer of 1 to 50 or 10 to 40.

 The amide block B is represented by the following general formula.

In the formula, Y is an aliphatic amide residue having a structure in which an aliphatic carboxylic acid and an aliphatic amine are condensed, and represented by the general formula -R ₄ -NHCOR ₅ -or -R _6- (wherein R ₄ represents a carbon number An alkylene group of 0 to 12; R ₅ is an alkylene group of 0 to 12 carbon atoms; R ₆ is an alkylene group of 1 to 12 carbon atoms); and m is an amide block in the polyesteramide copolymer. And an integer of 1 to 25.

JP-A-56-22324 discloses the above-mentioned JP-A-54-1.
No. 19594 discloses a biodegradable agricultural multi-film formed from a copolymer used for a biodegradable film disclosed in Japanese Patent Application Publication No. 19594.

JP-B-57-26688 discloses that a mixture of a high-molecular-weight polycaprolactone and a high-molecular-weight aliphatic polyamide is heated and melted at a temperature higher than their melting points, and the ester-amide exchange reaction is carried out until a product having a distinct melting point drop is obtained. A process for producing a biodegradable polyester amide copolymer is disclosed. This biodegradable polyester amide copolymer is a copolymer in which many ester blocks A and amide blocks B are alternately bonded. The above ester block A has the formula And n is the average degree of polymerization of the ester block contained in the polyesteramide copolymer, and is not particularly limited, but is usually an integer of 1 to 50.

 The amide block B is represented by the following general formula.

In the formula, Y is an aliphatic amide residue having a structure in which an aliphatic carboxylic acid and an aliphatic amine are condensed, and represented by the general formula -R ₄ -NHCOR ₅ -or -R _6- (wherein R ₄ represents a carbon number An alkylene group of 0 to 12, R ₅ is an alkylene group of 0 to 12 carbon atoms, and R ₆ is an alkylene group of 1 to 12 carbon atoms), and m is an amide block in the polyesteramide copolymer. It is an average degree of polymerization and is an integer of 1 to 25.

JP-A-57-61286 and JP-B-59-8365 disclose a biodegradable product comprising an ester-amide exchange reaction product obtained by the production method disclosed in the above-mentioned JP-B-57-26688. A packaging film and a biodegradable agricultural multi-film are disclosed, respectively.

Object of the Invention The present invention is intended to solve the problems associated with the prior art as described above, and retains the inherent properties of polyamide, such as mechanical strength and heat resistance, as well as biodegradability. An object of the present invention is to provide a polyamide resin composition excellent in the above.

Another object of the present invention is to provide a stretch molded article using a polyamide resin composition having the above-described excellent properties.

SUMMARY OF THE INVENTION A polyamide resin composition according to the present invention is a polyamide resin composition containing a polyamide and a copolyamide, wherein the copolyamide comprises: (a) a structural unit represented by the following formula [I]; (B) the following formula [I] 'and the structural unit represented _{^{by, -OR 0 -O n ... [I}} ]' [ where in the formula [I] ', R ⁰ is 2 carbon atoms
It is at least one group selected from the group consisting of 6 alkylene groups, and n is a positive integer of 2 to 100. (C) a structural unit represented by the following formula [II]; [However, in the formula [II], R ¹ has 4 to 10 carbon atoms.
Alkylene group, p- phenylene group, m- phenylene, 2,6-naphthylene group, is at least one group selected from the group consisting of 4,4'-biphenylene, R ² is the number of carbon atoms It is at least one group selected from the group consisting of 4 to 10 alkylene groups, 2,2-propylenebis (4-cyclohexylene) groups, and 1,4-phenylenedimethylene groups. (D) Structural unit represented by the following formula [III] [However, in the formula [III], R ³ has ³ to 1 carbon atoms.
It is at least one group selected from the group consisting of one alkylene group. Wherein the (a) constituent unit and (b) constituent unit are essential constituent units, and the molar ratio of (a) constituent unit / (b) constituent unit is from 100/0 to 50/50 (provided that , Excluding 100/0)
[(A) structural unit + (b) structural unit]
/ [(C) structural unit + (d) structural unit] has a molar ratio of 10/9
Within the range of 0 to 80/20, intrinsic viscosity [η] is 0.2 to 1.5 dl
/ g in the range of substantially linear copolyamide.

The stretched polyamide resin article according to the present invention is a stretched article formed from a polyamide resin composition containing a polyamide and a copolyamide, wherein the copolyamide comprises: (a) a structural unit represented by the following formula [I]: When, (B) the following formula [I] 'and the structural unit represented _{^{by, -OR 0 -O n ... [I}} ]' [ where in the formula [I] ', R ⁰ is 2 carbon atoms
It is at least one group selected from the group consisting of 6 alkylene groups, and n is a positive integer of 2 to 100. (C) a structural unit represented by the following formula [II]; [However, in the formula [II], R ¹ has 4 to 10 carbon atoms.
Alkylene group, p- phenylene group, m- phenylene, 2,6-naphthylene group, is at least one group selected from the group consisting of 4,4'-biphenylene, R ² is the number of carbon atoms It is at least one group selected from the group consisting of 4 to 10 alkylene groups, 2,2-propylenebis (4-cyclohexylene) groups, and 1,4-phenylenedimethylene groups. (D) Structural unit represented by the following formula [III] [However, in the formula [III], R ³ has ³ to 1 carbon atoms.
It is at least one group selected from the group consisting of one alkylene group. Wherein the (a) constituent unit and (b) constituent unit are essential constituent units, and the molar ratio of (a) constituent unit / (b) constituent unit is from 100/0 to 50/50 (provided that , 100/0), and the molar ratio of [(a) structural unit + (b) structural unit] / [(c) structural unit + (d) structural unit]
It is in the range of 10/90 to 80/20 and the intrinsic viscosity [η] is 0.2 to
It is in the range of 1.5 dl / g and is characterized by being a substantially linear copolyamide.

The polyamide resin composition according to the present invention retains properties inherent to polyamide, such as mechanical strength and heat resistance, and is excellent in biodegradability. Therefore,
The stretch molded article obtained by using the polyamide resin composition according to the present invention retains the inherent properties of polyamide, such as mechanical strength and heat resistance, and is excellent in biodegradability. Therefore, the stretched molded article according to the present invention,
When left in the natural world, it is decomposed by enzymes present in the natural world, so that it is possible to prevent environmental pollution by the stretched polyamide resin molded article.

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, the polyamide resin composition and the stretched molded article according to the present invention will be specifically described.

First, the polyamide resin composition of the present invention will be described.

The polyamide resin composition of the present invention is a composition comprising a polyamide and a specific copolyamide.

Polyamide The polyamide used in the present invention is a conventionally known polyamide, and specific examples include the following polyamides.

(1) Nylon 6 by ring-opening polymerization of ε-caprolactam (2) Nylon 66 by condensation polymerization of hexamethylenediamine and adipic acid (3) Nylon 610 by condensation polymerization of hexamethylenediamine and sebacic acid (4) 11-aminoundecane Nylon by condensation polymerization of acid
11 (5) Nylon 12 by ring-opening polymerization of ω-aminolaurolactam 12 (6) Copolymerized nylon copolyamide having two or more components among nylons of (1) to (5) In the polyamide resin composition of the present invention, The copolyamide used includes: (a) a structural unit represented by the following formula [I]; (B) the following formula [I] 'and the structural unit represented _{^{by, -OR 0 -O n ... [I}} ]' [ where in the formula [I] ', R ⁰ is 2 carbon atoms
It is at least one group selected from the group consisting of 6 alkylene groups, and n is a positive integer of 2 to 100. (C) a structural unit represented by the following formula [II]; [However, in the formula [II], R ¹ has 4 to 10 carbon atoms.
Alkylene group, p- phenylene group, m- phenylene, 2,6-naphthylene group, is at least one group selected from the group consisting of 4,4'-biphenylene, R ² is the number of carbon atoms It is at least one group selected from the group consisting of 4 to 10 alkylene groups, 2,2-propylenebis (4-cyclohexylene) groups, and 1,4-phenylenedimethylene groups. (D) Structural unit represented by the following formula [III] [However, in the formula [III], R ³ has ³ to 1 carbon atoms.
It is at least one group selected from the group consisting of one alkylene group. Wherein the (a) constituent unit and (b) constituent unit are essential constituent units, and the molar ratio of (a) constituent unit / (b) constituent unit is from 100/0 to 50/50 (provided that , 100/0), and the molar ratio of [(a) structural unit + (b) structural unit] / [(c) structural unit + (d) structural unit]
It is in the range of 10/90 to 80/20 and the intrinsic viscosity [η] is 0.2 to
It is in the range of 1.5 dl / g and is a substantially linear copolyamide.

The copolyamide used in the present invention includes (a) a structural unit represented by the above formula [I], (b) a structural unit represented by the formula [I] ', and (c) a structural unit or (d). A ternary polyamide comprising structural units, (a)
There is a quaternary polyamide composed of a structural unit, (b) a structural unit, (c) a structural unit and (d) a structural unit.

The structural unit (a) constituting the copolyamide used in the present invention is poly-ε-caprolactone or poly-ε-caprolactone.
It is a structural unit derived from caproate.

The structural unit (b) constituting the copolyamide used in the present invention is represented by the following formula [I] '.

_{^{-OR 0 -O n ... [I]}} '[ However, the formula [I]' in, R ⁰ is 2 carbon atoms
It is at least one group selected from the group consisting of 6 alkylene groups, and may be two or more groups. n is a positive integer of 2 to 100, preferably 2 to 50.

The structural unit (c) constituting the copolyamide used in the present invention is represented by the following formula [II].

In the formula [II], R ¹ is an alkylene group having 4 to 10 carbon atoms, a p-phenylene group, a m-phenylene group, a 2,6-
It is at least one group selected from the group consisting of a naphthylene group and a 4,4'-biphenylene group, and may be two or more groups. R ² is at least one group selected from the group consisting of an alkylene group having 4 to 10 carbon atoms, a 2,2-propylenebis (4-cyclohexylene) group, and a 1,4-phenylenedimethylene group. There may be two or more groups.

The structural unit (d) constituting the copolyamide used in the present invention is represented by the following formula [III].

In the formula [III], R ³ is at least one group selected from the group consisting of alkylene groups having 3 to 11 carbon atoms, and may be two or more groups.

The copolyamide used in the present invention contains (a) a structural unit and (b) a structural unit as essential structural units, and the molar ratio of (a) the structural unit / (b) the structural unit is from 100/0 to 50/50. (Except 100/0), preferably 100 / 0-60 / 40 (except 100/0), more preferably 100 / 0-70 / 30
(However, excluding 100/0) and [(a) structural unit + (b) structural unit] / [(c) structural unit + (d)
Molar ratio of the constituent units] is 10/90 to 90/10, preferably 15/8
It is in the range of 5-15 / 85, more preferably 20 / 80-20 / 80.

The copolyamide used in the present invention has an intrinsic viscosity [η] of 0.2 to 1.5 dl / g, preferably 0.3 to 1.5, measured at 25 ° C. in a dimethylformamide solution containing 2% by weight of lithium chloride.
It is within the range of 1.2dl / g. When a copolyamide having an intrinsic viscosity [η] in the above range is used, a polyamide resin composition having good melt moldability, stretchability and mechanical properties can be obtained.

The copolyamide used in the present invention has a substantially linear structure. Here, the “substantially linear structure” means that the polyamide has a linear or branched chain structure and does not have a gel-like crosslinked structure (network structure).

Method for Producing Copolyamide The copolyamide used in the present invention can be produced by an ester-amide exchange reaction between poly-ε-caproate or poly-ε-caprolactone and the corresponding constituent polyamide.

The catalyst used in the above ester-amide exchange reaction is the same as a catalyst generally used as a catalyst for the transesterification reaction.Specifically, a metal compound such as calcium, magnesium, lithium, zinc, cobalt, or manganese is used. Can be used. As the form of these compounds, oxides, hydroxides, halides, inorganic acid salts, organic acid salts and the like are used.

The above-mentioned ester-amide exchange reaction is carried out under the same conditions as the reaction conditions in the final stage of the production of the above-mentioned component polyamide. For example, under nitrogen atmosphere, 240-300
The ester-amide exchange reaction is carried out for 1 to 6 hours while stirring at ℃.

In the polyamide resin composition according to the present invention, the polyamide is 5 to 95 parts by weight, preferably 10 to 90 parts by weight, based on 100 parts by weight of the total amount of the polyamide and the copolyamide.
More preferably, it is used in an amount of 50 to 90 parts by weight. Further, the copolyamide is 5 to 95 parts by weight, preferably 10 to 90 parts by weight based on 100 parts by weight of the total amount of the polyamide and the copolyamide.
It is used in an amount of 10 parts by weight, more preferably 10 to 50 parts by weight.

Polyamide resin composition production method The polyamide resin composition according to the present invention, the polyamide and copolyamide, the melt kneading by an extruder or a conventionally known mixing method such as pellet mixing before injection molding arbitrarily adopted. Can be manufactured.

The polyamide resin composition of the present invention comprises a polyamide and a copolyamide as essential components as described above, and optionally includes an organic or inorganic filler, an antioxidant, and an ultraviolet ray in addition to these essential components. Absorbers, light protectants, heat stabilizers, phosphite stabilizers, peroxide decomposers, basic auxiliaries,
Nucleating agents, plasticizers, lubricants, antistatic agents, flame retardants, pigments,
It may contain a dye or the like.

The polyamide resin composition of the present invention can be used in a non-stretched state as a film, a sheet, a fiber, a container, or a molded article of various other shapes by using a usual molding method.

Furthermore, the polyamide resin composition of the present invention can be formed into a film, sheet, container or the like by stretching.

Next, the stretched polyamide resin article of the present invention will be described.

The stretch molded article of the polyamide resin composition of the present invention includes a uniaxial stretch molded article and a biaxial stretch molded article, and the form may be any of a film, a sheet, and a fiber. Here, when the stretched polyamide resin molded article of the present invention is a uniaxially stretched molded article, the stretching ratio is usually 1.1 to 10 times,
The range is preferably 1.2 to 8 times, particularly preferably 1.5 to 7 times. Further, when the stretched polyamide resin molded article of the present invention is a biaxially stretched molded article, the stretching ratio is usually 1.1 to 8 times, preferably 1.2 to 7 times, particularly preferably 1.5 to 6 times in the vertical axis direction. Range is 1.1 times to 8 times in the horizontal axis direction.
Times, preferably 1.2 to 7 times, particularly preferably 1.5 to 6 times. The oriented polyamide resin stretched article can be subjected to heat setting depending on the purpose of use.

As a method for producing a stretch molded article from the polyamide resin composition of the present invention, any conventionally known method can be employed. In general, an original molded article such as a film or sheet molded from the polyamide resin composition or a composition containing the additive as needed, as it is, or as such, was once cooled and solidified to a temperature below the glass transition point. After reheating, the original molded body is subjected to a stretching treatment at a temperature within a range from the glass transition point to the melting point, preferably 80 ° C. higher than the glass transition point or the glass transition point. The heat setting of the stretched molded body is performed by heating the stretched body at the above stretching temperature or higher temperature for a short time.

As a method for producing a stretched molded article from the polyamide resin composition of the present invention, when the original molded article is a film or a sheet, a method of uniaxially stretching an unstretched film or sheet (uniaxial stretching), After stretching in the horizontal direction (biaxial stretching), simultaneously stretching in the vertical and horizontal directions (biaxial stretching), and further sequentially in any one direction after biaxial stretching Examples of the method include a method in which stretching is repeated, a method in which biaxial stretching is performed and then stretching is performed in both directions, and a so-called vacuum forming method in which stretching is performed by reducing the pressure between a film or sheet and a mold.

Further, these stretched polyamide resin molded articles can be manufactured in a form laminated with another resin.

As a method for producing a stretched laminate including a layer composed of the polyamide resin composition of the present invention, an original molded article such as a film or sheet of a polyamide resin composition, and an original molded article such as a film or sheet of another resin, Examples of the method include a method of stretching after laminating a single layer or a plurality of layers, and a method of bonding a film or sheet of another resin to a stretched molded article made of the polyamide resin composition of the present invention.

Since the stretched polyamide resin article of the present invention is excellent in properties such as mechanical strength, it can be used for various uses such as films, sheets, tubular bodies, containers and bottles.

Effect of the Invention Since the polyamide resin composition according to the present invention is composed of a specific copolyamide containing the above-mentioned (a) structural unit and (b) a structural unit as an essential structural unit, and a polyamide, the polyamide is originally used. While maintaining properties such as mechanical strength and heat resistance, it is also excellent in biodegradability.

The stretch molded article obtained by using the polyamide resin composition according to the present invention retains the inherent properties of polyamide, such as mechanical strength and heat resistance, and is excellent in biodegradability. Therefore, when the stretched molded article according to the present invention is left in the natural world, it is decomposed by the enzyme present in the natural world, so that environmental pollution by the stretched polyamide resin molded article can be prevented. In addition, the higher the content of the copolyamide containing the constituent units (a) and (b), the higher the rate of enzymatic decomposition of the stretched polyamide resin molded article, so that it is contained in the stretched polyamide resin molded article. By controlling the amount of copolyamide, it is possible to control the rate of decomposition of the stretched polyamide resin article by the enzyme.

Hereinafter, the present invention will be described with reference to examples, the present invention,
It is not limited to these examples.

Reference Example 400 parts by weight of polycaprolactone [manufactured by Daicel Chemical Industries, Ltd., PALACCEL-H7] dried at room temperature, a pressure of 300 mmHg and a drying time of 48 hours in the presence of nitrogen gas, 90 ° C. in the presence of nitrogen gas, Nylon 12 [manufactured by Daicel Huls Co., Ltd., DAIAMID L-1801] 600 parts by weight and ester-dried under the conditions of a pressure of 300 mmHg and a drying time of 24 hours.
After loading 4.3 parts by weight of zinc chloride as a transamidation catalyst into a stainless steel autoclave equipped with a stirrer, the mixture is melt-kneaded at 270 ° C. for 4 hours in a nitrogen atmosphere, and contains the above structural unit (a) by ester-amide exchange reaction. A copolyamide was obtained. The resulting copolyamide has an intrinsic viscosity [η] of 0.68 dl / g and a glass transition temperature (Tg) of 54 ° C.
And the melting point (Tm) was 168 ° C.

Next, 100 parts by weight of nylon 6 (Ube Nylon 1013B) and 30 parts by weight of the above copolyamide were mixed and melt-extruded at about 230 ° C. using an extruder to produce pellets of the composition.

Further, a press sheet having a thickness of about 200 μm was produced by press molding using the pellets.
As a result of measuring the mechanical strength of the obtained press sheet, the tensile strength at break was 490 kg / cm ² and the elongation was 160%.

Next, the press sheet was simultaneously biaxially stretched three times in the machine direction and the transverse direction using a biaxial stretching apparatus.
The biaxially stretched film thus obtained was stretched uniformly and had a thickness of about 22 μm. The mechanical strength of the biaxially stretched film was measured. As a result, the tensile strength at break was 1550 kg / cm ² , the tensile elongation was 110%, and the tensile modulus was 15,000 kg / cm ² .

Next, the above-mentioned press sheet and the biaxially stretched film are respectively immersed in the aerobic activated sludge tank used in the premises of Mitsui Petrochemical Industry Co., Ltd. Iwakuni-Ohtake Plant (Waki-cho, Kuga-gun, Yamaguchi Prefecture) and left. did. Next, it was taken out when the immersion period was 12 months, washed out and dried after each month, washed with water and dried, and its properties were examined. As a result, it was found that any of them was easily broken by bending and the brittleness was increased. As a result of measuring the respective mechanical strengths, the tensile break strength of the pressed sheet was 220 kg / cm ^{2 and the} elongation was 18%. The biaxially stretched film had a tensile strength at break of 420 kg / cm ² and an elongation of 16
%, And the tensile modulus was 1600 kg / cm ² . All of these values were significantly lower than those before immersion in the aerobic activated sludge tank.

Comparative Example 1 Press molding was performed using the nylon 6 used in the reference example to produce a press sheet having a thickness of about 200 μm.
The mechanical strength of this press sheet is 530k tensile breaking strength
g / cm ² and elongation was 180%.

Further, the press sheet was simultaneously biaxially stretched three times in the vertical and horizontal directions in the same manner as in the reference example to produce a biaxially stretched film having a thickness of about 22 μm. The mechanical strength of this biaxially stretched film is 1710 kg / c
m ² , elongation 140%, and tensile modulus 18,000 kg / cm ² .

Next, each of the press sheet and the biaxially stretched film was immersed in an aerobic activated sludge tank for 12 months in the same manner as in Reference Example, and changes in properties thereafter were examined. as a result,
No change was observed in the appearance of both the press sheet and the biaxially stretched film, and no cracks occurred in any of the folded sheets. Further, as a result of measuring the mechanical strength of each of them, the tensile strength at break of the pressed sheet was 440 kg / cm ² , and the elongation was 220%. The biaxially stretched film has a tensile strength at break of 1600 kg / cm ² , an elongation of 165% and a tensile modulus of 16,000.
kg / cm ² , and in each case, there was almost no change compared to before immersion in the activated sludge tank.

Examples As raw materials used for the production of a copolyamide containing the (a) structural unit and (b) structural unit, 300 parts by weight of polycaprolactone of Reference Example, 12600 parts by weight of Nylon of Reference Example, and nitrogen gas were used. Except that 100 parts by weight of polyethylene glycol (n = 400) dried under the conditions of room temperature, a pressure of 300 mmHg and a drying time of 72 hours were used in the same manner as in Reference Example. A contained copolyamide was obtained. The obtained copolyamide has an intrinsic viscosity [η] of 0.72 dl / g and a glass transition temperature (Tg).
Was 51 ° C, and the melting point (Tm) was 167 ° C.

Next, 100 parts by weight of nylon 6 and 30 parts by weight of the above copolyamide were mixed in the same manner as in the Reference Example, and then melt-extruded at about 230 ° C. using an extruder to produce pellets of the composition. Further, a pressed sheet having a thickness of about 200 μm was prepared by press molding using the pellets of the composition.
As a result of measuring the mechanical strength of the obtained press sheet, it was found that the tensile strength at break was 450 kg / cm ² and the elongation was 150%.

Further, a biaxially stretched film having a thickness of about 22 μm was produced by biaxially stretching the press sheet in the same manner as in the reference example. As a result of measuring the mechanical strength, it was found that the tensile strength at break was 1470 kg / cm ² , the tensile elongation was 120%, and the tensile modulus was 16,000 kg / cm ² .

Next, the press sheet and the biaxially stretched film were immersed in an aerobic activated sludge tank for 12 months in the same manner as in Reference Example, and changes in properties after that were examined. As a result, it was found that both the press sheet and the biaxially stretched film were cracked and fragile when bent. Furthermore, the result of measuring the mechanical strength of each, the tensile breaking strength of the press sheet is 180 kg / cm ² ,
The growth was 13%. The biaxially stretched film had a tensile breaking strength of 340 kg / cm ² , an elongation of 17%, and a tensile modulus of 14000 kg / cm ² . All of these values were significantly lower than those before immersion in the aerobic activated sludge tank.

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Claims (2)

(57) [Claims] 1. A polyamide resin composition comprising a polyamide and a copolyamide, wherein the copolyamide comprises: (a) a structural unit represented by the following formula [I]: (B) the following formula [I] 'and the structural unit represented _{^{by, -OR 0 -O n ... [I}} ]' [ where in the formula [I] ', R ⁰ is 2 carbon atoms
It is at least one group selected from the group consisting of 6 alkylene groups, and n is a positive integer of 2 to 100. (C) a structural unit represented by the following formula [II]; [However, in the formula [II], R ¹ has 4 to 10 carbon atoms.
Is at least one group selected from the group consisting of an alkylene group, a p-phenylene group, an m-phenylene group, a 2,6-naphthylene group and a 4,4′-biphenylene group, and R ² has 4 carbon atoms. And at least one group selected from the group consisting of an alkylene group, a 2,2-propylenebis (4-cyclohexylene) group and a 1,4-phenylenediethylene group. (D) Structural unit represented by the following formula [III] [However, in the formula [III], R ³ has ³ to 1 carbon atoms.
It is at least one group selected from the group consisting of one alkylene group. Wherein the (a) constituent unit and (b) constituent unit are essential constituent units, and the molar ratio of (a) constituent unit / (b) constituent unit is from 100/0 to 50/50 (provided that , Excluding 100/0)
[(A) structural unit + (b) structural unit]
/ [(C) structural unit + (d) structural unit] has a molar ratio of 10/9
Within the range of 0 to 80/20, intrinsic viscosity [η] is 0.2 to 1.5 dl
/ g, which is a substantially linear copolyamide. 2. A stretch molded article formed from a polyamide resin composition containing a polyamide and a copolyamide, wherein the copolyamide comprises: (a) a structural unit represented by the following formula [I]: (B) the following formula [I] 'and the structural unit represented _{^{by, -OR 0 -O n ... [I}} ]' [ where in the formula [I] ', R ⁰ is 2 carbon atoms
It is at least one group selected from the group consisting of 6 alkylene groups, and n is a positive integer of 2 to 100. (C) a structural unit represented by the following formula [II]; [However, in the formula [II], R ¹ has 4 to 10 carbon atoms.
Is at least one group selected from the group consisting of an alkylene group, a p-phenylene group, an m-phenylene group, a 2,6-naphthylene group and a 4,4′-biphenylene group, and R ² has 4 carbon atoms. And at least one group selected from the group consisting of an alkylene group, a 2,2-propylenebis (4-cyclohexylene) group and a 1,4-phenylenediethylene group. (D) Structural unit represented by the following formula [III] [However, in the formula [III], R ³ has ³ to 1 carbon atoms.
It is at least one group selected from the group consisting of one alkylene group. Wherein the (a) constituent unit and (b) constituent unit are essential constituent units, and the molar ratio of (a) constituent unit / (b) constituent unit is from 100/0 to 50/50 (provided that , Excluding 100/0)
[(A) structural unit + (b) structural unit]
/ [(C) structural unit + (d) structural unit] has a molar ratio of 10/9
Within the range of 0 to 80/20, intrinsic viscosity [η] is 0.2 to 1.5 dl
/ g, which is a substantially linear copolyamide.