JPH036263A - Polyamide resin composition and its use - Google Patents

Abstract

PURPOSE:To prepare a polyamide resin compsn. excellent in the biodegradability while retaining its inherent mechanical strengths and heat resistance by compounding a polyamide with an epsilon-caproate-contg. polyamide. CONSTITUTION:A polyamide resin compsn. is obtd. by compounding a polyamide with an epsilon-caproate-contg. polyamide which is a linear copolyamide having a limiting viscosity number [eta] of 0.2-1.5dl/g, and comprising repeating units of formula I (A), repeating units of formula II (wherein R<0> is 2-6C alkylene; and (n) is 2-100) (B), repeating units of formula III (C), and repeating unit of formula IV (wherein R<3> is 3-11C alkylene) (D), the molar ratio of A to B being (100:0)-(50:50) and that of A+B to C+D being (10:90)-(80:20).

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a polyamide resin composition that retains the properties inherent to polyamide such as mechanical strength and heat resistance, and has excellent biodegradability, and a polyamide resin composition that has excellent biodegradability. The present invention relates to a stretch molded article using a material.

Technical background of the invention Polyamides, particularly polycapramide (nylon 6) and polyhexamethylene aziboamide (nylon 66), have excellent properties such as mechanical strength and heat resistance, and are widely used in films, fibers, molding materials, etc. It is used. but,
With the increase in the amount of polyamide molded products used, a large amount of used polyamide molded products are being left without being incinerated. Moreover, conventional polyamide molded products
Biodegradability is extremely low, and polyamide molded products left in nature will not decompose for a long time and will retain their shape.
There was a problem that it caused environmental pollution.

By the way, ε-caproate-containing substances, which are known substances, are biodegradable and are known to be decomposed by enzymes such as lipase. However, since the ε-caproate-containing copolyamide alone has poor mechanical strength, heat resistance, and economic efficiency, it has been difficult to put into practical use a stretched molded article made from the ε-caproate-containing copolyamide alone.

The present inventors conducted intensive research to obtain polyamide resin compositions and stretched molded products that retain the inherent properties of polyamides such as mechanical strength and heat resistance, and have excellent biodegradability, and identified polyamides as polyamides. A composition was obtained by blending the polyamide with an ε-caproate-containing copolyamide, and this composition retained the properties inherent to polyamide, such as mechanical strength and heat resistance, while also being able to stretch with excellent biodegradability. It was discovered that a molded article could be obtained, and the present invention was completed.

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

1 100-X-C÷-1ro In the formula, (In the formula, R1 is an alkylene group having 2 to 20 carbon atoms, R is an alkylene group having 0 to 12 carbon atoms, and R3 is an alkylene group having 1 to 5 carbon atoms.), and n is polyesteramide. It is the average degree of polymerization of the ester blocks contained in the copolymer, and although not particularly limited, it is usually an integer of 1 to 50.10 to 40.

Moreover, the amide block B is represented by the following general formula.

-(-N H-Y -C→- 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 the general formula % formula % (in the formula, R4 is a carbon 0 to 12 alkylene groups, R is an alkylene group having 0 to 12 carbon atoms, R6 is an alkylene group having 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 from 1 to 25.

Furthermore, JP-A-56-22324 discloses a biodegradable film made from the copolymer used in the biodegradable film disclosed in JP-A-54-119594. An agricultural mulch film is disclosed.

Japanese Patent Publication No. 57-26688 discloses that a mixture of high molecular weight polycaprolactone and high molecular weight aliphatic polyamide is heated and melted above their melting points, and an ester amide exchange reaction is carried out until a product showing a clear melting point depression is obtained. A method for producing a biodegradable polyesteramide copolymer is disclosed.

This biodegradable polyesteramide copolymer is a copolymer in which a large number of ester blocks A and amide blocks B are alternately bonded. The above ester block A is represented by the formula %, where n is the average degree of polymerization of the ester blocks contained in the polyesteramide copolymer, and is usually an integer from 1 to 50, although it is not particularly limited. .

Moreover, the amide block B is represented by the following general formula.

1 -f-NH-Y-C→- In the formula, Y is an aliphatic amide residue having a structure in which an aliphatic carboxylic acid and an aliphatic amine are condensed; In the formula, R4 is an alkylene group having 0 to 12 carbon atoms, R5 is an alkylene group having 0 to 12 carbon atoms, and R6 is an alkylene group having 1 to 12 carbon atoms.
is an alkylene group), where m is the average degree of polymerization of the amide blocks in the polyesteramide copolymer and is an integer of 1 to 25.

Also, Japanese Patent Publication No. 57-61286 and Special Publication No. 59-
Publication No. H65 discloses a biodegradable packaging film and a biodegradable agricultural mulch film made of an ester-amidation exchange reaction product obtained by the manufacturing method disclosed in Japanese Patent Publication No. 57-26688. Each is disclosed.

Purpose of the Invention The present invention aims to solve the problems associated with the prior art as described above, and aims to maintain the inherent properties of polyamide, such as mechanical strength and heat resistance, while also achieving biodegradability. The purpose is to provide a polyamide resin composition with excellent properties.

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

Summary of the Invention The polyamide resin composition according to the present invention is a polyamide resin composition comprising a polyamide and an ε-caproate-containing copolyamide, wherein the ε-caproate-containing copolyamide has the following formula [
I] and 0
...[I](b) The structural unit represented by the following formula [I1' and -0(RO-0+-...[■
1' [However, in formula [■1', RO has 2 carbon atoms]
-6 alkylene groups, and n is a positive integer of 2 to 100.

] (c) The structural unit represented by the following formula [■] and [However,
In formula [I[], ] structure is an alkylene group having 4 to 10 carbon atoms, p-phenylene group, m-phenylene group, 2
．． is at least one group selected from the group consisting of 6-naphthylene group and 4,4'-biphenylene group, and R2 is an alkylene group having 4 to 10 carbon atoms, z, 2-propylene bis(4-cyclohexyl group); silene) group, I,4-fuynylene dimethylene group. (d) The structural unit represented by the following formula [I[[] -C-R3-NH- 1 0...[I[] [However, in the formula [m], R3 has 3 to 3 carbon atoms.
It is at least one group selected from the group consisting of 11 alkylene groups. ], and the molar ratio of the (a) structural unit/(b) structural unit is within the range of 10010 to 50150,
The molar ratio of [(a) structural unit (b) structural unit]/[(c) structural unit + (d) structural unit] is 10/90 to 80/
20, and the intrinsic viscosity [η] is 0°2 to 1.5
dl/g and is characterized by a substantially linear copolyamide.

The polyamide resin stretched molded article according to the present invention is a stretched molded article formed from a polyamide resin composition containing a polyamide and an ε-caproate-containing copolyamide, wherein the ε-caproate-containing copolyamide has the following formula: (a) [
The constituent unit represented by I1 and 0
・
The structural unit represented by the structural formula [I]' is the same as the structural unit represented by the structural formula [I]'. However, in the formula [I1', RO is the number of carbon atoms. is 2
-6 alkylene groups, and n is a positive integer of 2 to 100.

] (c) A structural unit represented by the following formula [II] and 0
0 ... [
II] [However, in formula [I1], R1 is an alkylene group having 4 to 10 carbon atoms, p-phenylene group, Ol
- at least one group selected from the group consisting of a phenylene group, a 2,6-naphthylene group, and a 4,4'-biphenylene group, and R2 is an alkylene group having 4 to 10 carbon atoms, 2.2- Propylene bis(4-cyclohexylene)
It is at least one type of group selected from the group consisting of a group, (1), and a 4-phenylene dimethylene group. ](] Constituent formula [I
II] structural unit represented by -C-R''-NH- 10... [m] [However, in formula [m], R3 has 3 to 3 carbon atoms.
It is at least one group selected from the group consisting of 11 alkylene groups. ], and the molar ratio of the (a) structural unit/(b) structural unit is within the range of 10010 to 50150,
The molar ratio of [(a) structural unit (b) structural unit]/[(c) structural unit + (d) structural unit] is 10/90 to 80/
The intrinsic viscosity [η is within the range of 0.2 to 1.5
dllH and is characterized by a substantially linear copolyamide.

The polyamide resin composition according to the present invention retains the properties inherent to polyamide, such as mechanical strength and heat resistance, and has excellent biodegradability. Therefore, the stretched molded article obtained using the polyamide resin composition according to the present invention retains the properties inherent to polyamide, such as mechanical strength and heat resistance, and has excellent biodegradability. Therefore, when the stretched molded article according to the present invention is left in nature, it is decomposed by enzymes that exist in nature, so that environmental pollution caused by the polyamide resin stretched molded article can be prevented.

DETAILED DESCRIPTION OF THE INVENTION The polyamide resin composition and stretched molded article according to the present invention will be specifically explained below.

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

The polyamide resin composition of the present invention is a composition comprising a polyamide and an ε-caproate-containing copolyamide.

Polyamide The polyamide used in the present invention is a conventionally known polyamide, and specifically includes the following polyamides.

(1) Nylon 6 produced by ring-opening polymerization of ε-caprolactam (2) Nylon 66 produced by polycondensation of hexamethylene diamine and adipic acid (3) Nylon 610 produced by polycondensation of hexamethylene diamine and sebacic acid (4) 11- Nylon 11 produced by condensation polymerization of aminoundecanoic acid (5) Nylon 12 produced by ring-opening polymerization of ω-aminolaurolactam (6) Copolymerized nylon ε- having two or more components among the nylons (1) to (5) Caproate-containing copolyamide ε- used in the polyamide resin composition of the present invention
The caproate-containing copolyamide is composed of (a) a structural unit represented by the following formula [I], (b) a structural unit represented by the following formula [■1', [wherein, in the formula [I]', RO
is at least one group selected from the group consisting of alkylene groups having 2 to 6 carbon atoms, and n is a positive integer of 2 to 100. (c) a structural unit represented by the following formula [I13], [wherein R1 is an alkylene group having 4 to 10 carbon atoms, p-phenylene group, m-phenylene group, 2
．． R2 is at least one group selected from the group consisting of 6-naphthylene group and 4,4'-biphenylene group, and R2 is an alkylene group having 4 to 1 carbon atoms, 2,2-propylene bis(4-cyclohexyl group); silene) group, and 1,4-phenylene dimethylene group. ](]Structural unit represented by structural formula [III] -C-R3-NH- 10... [I![] [However,] In structure m], R3 has 3 to 3 carbon atoms.
It is at least one group selected from the group consisting of 11 alkylene groups. ], and the molar ratio of the (a) structural unit/(b) structural unit is within the range of 10010 to 50150,
The molar ratio of [(a) structural unit (b) structural unit]/[(c) structural unit (d) structural unit] is 10/90 to 80/2
0, and the intrinsic viscosity [η] is 0.2 to 1.5 d.
llH and is a substantially linear copolyamide.

The ε-caproate-containing copolyamide used in the present invention includes (a) a structural unit represented by the above formula El],
A binary polyamide consisting of the (C) structural unit represented by formula [I] or the (d) structural unit represented by formula [m], (a) structural unit, (C) structural unit, and (d) structure A ternary polyamide consisting of units, (a) structural units;
A ternary polyamide consisting of (b) structural units and (c) structural units or (d) structural units represented by the formula [1', (a) structural units, (b) structural units, (c) There is a quaternary polyamide consisting of a structural unit and (d) a structural unit.

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

In addition, the structural unit (b) constituting the ε-caproate-containing copolyamide used in the present invention is represented by the following formula % formula % [In the formula 1', RO is a group consisting of an alkylene group having 2 to 6 carbon atoms. At least one type of group selected, and two or more types of groups may be used. n is 2 to 10
0, preferably a positive integer from 2 to 50.

The (c) structural unit constituting the ε-caproate-containing copolyamide used in the present invention is represented by the following formula [■].

In formula [II], R. is an alkylene group having 4 to 10 carbon atoms, p-phenylene group, m-phenylene group, 2
．． It is at least one type of group selected from the group consisting of a 6-naphthylene group and a 4,4'-biphenylene group, and may be two or more types of groups. □Also, R2 has 4 carbon atoms.
'~10 alkylene group, 22-propylene bis(4-
cyclohexylene) group,! At least one type of group selected from the group consisting of 4 to phenylene dimethylene groups, and two or more types of groups may be used.

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

-C-R''-NH- 10...[I[r] In formula [IIr], R3 is at least one group selected from the group consisting of alkylene groups having 3 to 11 carbon atoms. However, two or more types of groups may be used.

In the ε-caproate-containing copolyamide used in the present invention, the molar ratio of (a) structural unit/(b) structural unit is 10010 to 50150, preferably 10010 to 6
0/40, more preferably within the range of 10010 to 70/30, [(a) structural unit + (b) structural unit]/
The molar ratio of [(c) structural unit + (d) structural unit] is 10
/90 to 90/10, preferably 15/85 to 15/8
5, more preferably 20/80 to 20/8 (within the range of 11).

The ε-caproate-containing copolyamide used in the present invention has an intrinsic viscosity [η] of 0.2 to 1 as measured at 25°C in a dimethylformamide solution containing 2% by weight of lithium chloride.
, 5d7/g, preferably within the range of 0.3 to 1.2dj/g. When an ε-caproate-containing copolyamide having an intrinsic viscosity [η] within the above range is used, a polyamide resin composition having good melt moldability, stretchability, and mechanical properties can be obtained.

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

Method for producing ε-caproate-containing copolyamide The ε-caproate-containing copolyamide used in the present invention is produced by an ester-amide exchange reaction between poly-ε-caproate or poly-ε-caprolactone and the corresponding polyamide component. can do.

The catalyst used in the above ester-amidation exchange reaction is the same as the catalyst generally used for the transesterification reaction, and specifically, metal compounds such as calcium, magnesium, lithium, zinc, cobalt, and manganese are used. Can be used. The forms of these compounds include oxides, hydroxides, halides, inorganic acid salts,
Organic acid salts are used.

Moreover, the above-mentioned ester-amidation exchange reaction is carried out under the same conditions as the reaction conditions in the final stage of producing the polyamide of the above-mentioned constituent components. For example, under a nitrogen atmosphere, 240-3
The ester-amidation exchange reaction is carried out at 00 DEG C. with stirring for 6 hours.

Compounding ratio In the polyamide resin composition according to the present invention, the polyamide is contained in an amount of 5 to 95 parts by weight, preferably 10 to 90 parts by weight, more preferably 50 parts by weight, based on 100 parts by weight of the total amount of polyamide and ε-caproate-containing copolyamide. ~9
It is used in an amount of 0 parts by weight. Further, the ε-caproate-containing copolyamide is 5 to 95 parts by weight based on 100 parts by weight of the total amount of the polyamide and the ε-caproate-containing copolyamide.
It is used in an amount of preferably 10 to 90 parts by weight, more preferably 10 to 50 parts by weight.

Manufacturing method of polyamide resin composition The polyamide resin composition according to the present invention can be produced by mixing the above-mentioned polyamide and the ε-caproate-containing copolyamide using any conventionally known mixing method such as melt mixing using an extruder or pellet mixing before injection molding. It can be adopted and manufactured.

The polyamide resin composition of the present invention has polyamide and ε-caproate-containing copolyamide as essential components as described above, but in addition to these essential components, organic or inorganic fillers, oxidation inhibitor, ultraviolet absorber,
Contains photoprotectants, heat stabilizers, phosphite stabilizers, peroxide decomposers, basic adjuvants, nucleating agents, plasticizers, lubricants, antistatic agents, flame retardants, pigments, dyes, etc. Good too.

The polyamide resin composition of the present invention can be used in an unstretched state as a molded article in various shapes such as a film, sheet, fiber, container, etc. using a conventional molding method.

Furthermore, the polyamide resin composition of the present invention can be stretched and formed into a shape such as a film, sheet, or container.

Next, the polyamide resin stretch molded article of the present invention will be explained.

The stretched molded product of the polyamide resin composition of the present invention includes a -axially stretched molded product and a biaxially stretched molded product, and the form thereof may be any of a film, a sheet, and a fiber. Here, when the polyamide resin stretched molded product of the present invention is a Itsutsumugi stretched molded product, the stretching ratio is usually 1.1 to 10 times, preferably 1.2 to 8 times, particularly preferably 1. 5-7
This is twice the range. Further, when the polyamide resin stretched molded product of the present invention is a biaxially stretched molded product, the stretching ratio in the longitudinal axis direction is usually 1.1 to 8 times, preferably 1.2 to 7 times.
times, particularly preferably in the range of 1.5 to 6 times, and generally 1° in the horizontal axis direction, preferably in the range of 1.2 to 7 times, particularly preferably in the range of 1.5 to 6 times. be. The polyamide resin stretch molded article of the present invention can also be heat set depending on its intended use.

As a method for producing a stretched molded article from the polyamide resin composition of the present invention, any conventionally known method can be employed. In general, an original molded object such as a film or sheet formed from the polyamide resin composition or a composition further containing the additives as necessary is used as it is, or it is first cooled and solidified to a temperature below the glass transition point. The original molded body is then reheated and then stretched at a temperature ranging from the glass transition point to the melting point, preferably from the glass transition point to a temperature 80° C. higher than the glass transition point. Heat setting of the stretched molded product is carried out by heating for a short time at the stretching temperature or higher temperature.

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 sheet, a method of stretching an unstretched film or sheet in the unidirectional direction (-axial stretching); A method of stretching in the vertical axis direction and then further stretching in the horizontal axis direction (biaxial stretching), a method of stretching in the vertical axis direction and the horizontal axis direction simultaneously (biaxial stretching), a method of stretching in the longitudinal axis direction and the horizontal axis direction simultaneously (biaxial stretching), and a method of stretching in either one direction after biaxial stretching A method of repeating sequential stretching, a method of further stretching in both directions after biaxial stretching,
Examples include the so-called vacuum forming method in which stretch forming is performed by reducing the pressure in the space between a film or sheet and a mold.

Moreover, these polyamide resin stretch molded bodies can also be manufactured in a form in which they are laminated with other resins.

As a method for producing a stretched laminate including a layer made of the polyamide resin composition of the present invention, an original molded body such as a film or sheet of a polyamide resin composition is mixed with an original molded body such as a film or sheet of another resin, respectively. Examples include a method in which the polyamide resin composition is laminated into a single layer or multiple layers and then stretched, or a method in which a film or sheet of another resin is adhered to a stretched molded product made of the polyamide resin composition of the present invention.

The polyamide resin stretch molded article of the present invention has excellent properties such as mechanical strength, so it can be used in films, sheets, tubular bodies, etc.
It can be used for various purposes such as containers and bottles.

Effects of the Invention Since the polyamide resin composition according to the present invention is composed of a specific ε-caproate-containing copolyamide and polyamide, it retains the mechanical strength, heat resistance, and other properties inherent to polyamide. , has excellent biodegradability.

Moreover, the stretched molded article obtained using the polyamide resin composition according to the present invention retains the properties inherent to polyamide, such as mechanical strength and heat resistance, and has excellent biodegradability. Therefore, when the stretched molded article according to the present invention is left in nature, it is decomposed by enzymes that exist in nature, so that environmental pollution caused by the polyamide resin stretched molded article can be prevented. In addition, the higher the content of the ε-caproate-containing copolyamide, the faster the rate of enzyme decomposition of the stretched polyamide resin molded product, so the amount of the ε-caproate-containing copolyamide contained in the stretched polyamide resin molded product is adjusted. This makes it possible to control the rate of enzyme decomposition of the stretched polyamide resin molded product.

EXAMPLES The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples.

Example 1 Polycaprolactone [manufactured by Daicel Chemical Industries, Ltd. 1. PALACCEI.

-117] 400 parts by weight, 90°C in the presence of nitrogen gas,
Nylon 12 [manufactured by Daicel Huls, dried under conditions of 300IIIHg pressure and 24 hours drying time]
After loading 600 parts by weight of Diaamide L-1801 and 4.3 parts by weight of zinc chloride as an ester-amide exchange catalyst into a stainless steel autoclave equipped with a stirrer, melt mixing was performed at 270°C for 4 hours in a nitrogen atmosphere to convert the ester-amide into An ε-caproate-containing copolyamide was obtained by transamidation reaction. The obtained ε-caproate-containing copolyamide had an intrinsic viscosity [η] of 0.68 dJ/g, a glass transition temperature (Tg) of 54°C, and a melting point (Tm) of 168°C.

Next, nylon 6 (Ube nylon 1013B) 10
0 parts by weight and the above ε-caproate-containing copolyamide 3
After mixing with 0 parts by weight, the composition was melt-extruded at about 230° C. using an extruder to produce pellets of the composition.

Furthermore, press molding is performed using these pellets,
A press sheet having a thickness of about 200 μm was produced. As a result of measuring the mechanical strength of the obtained press sheet, the tensile strength at break was 490 kg/al and the elongation was 160%.

Next, this press sheet was simultaneously biaxially stretched 3 times in the machine direction and in the transverse direction using a biaxial stretching device. The biaxially stretched film thus obtained was uniformly stretched and had a thickness of about 22 μm. Further, as a result of measuring the mechanical strength of this biaxially stretched film, the tensile strength at break was 1550 kg/d, the tensile elongation was 110%, and the tensile modulus was 15000 kg/aIr.

Next, the above press sheet and biaxially stretched film were
Aerobic activated sludge used at the Mitsui Petrochemical Industries, Ltd. Iwakuni-Ohtake Plant (Waki-cho, Kuga-gun, Yamaguchi Prefecture) was enclosed at room temperature, and each sample was buried and left in the enclosure. Next, they were taken out after 12 months of burial, washed with water and dried, and then taken out after each month, and their properties were examined after washing and drying. As a result, it was found that all of them easily cracked when bent, making them more brittle. The results of measuring each mechanical strength were that the tensile strength at break of the press sheet was 220 kg/ai and the elongation was 18
%Met. Further, the biaxially stretched film had a tensile strength at break of 420 kg/1ffl, an elongation of 16%, and a tensile modulus of 16000 kg/cd. All of these values were significantly lower than the values before being buried in the aerobic activated sludge.

Comparative Example 1 Press molding was performed using the nylon 6 used in Example 1 to produce a press sheet having a thickness of about 200 μm. The mechanical strength of this press sheet is tensile strength at break of 5.
The weight was 30 kg/car, and the elongation was 180%.

Furthermore, as in Example 1, this press sheet was simultaneously biaxially stretched three times in the vertical and horizontal directions to produce a biaxially stretched film having a thickness of about 22 μm. The mechanical strength of this biaxially stretched film is tensile strength at break of 1710
kg/alr, elongation 140% and tensile modulus 1800
It was 0 kg/car.

Next, these press sheets and biaxially stretched films were each buried in aerobic activated sludge for 12 months in the same manner as in Example 1, and changes in properties thereafter were investigated. the result,
No change in appearance was observed in either the press sheet or the biaxially stretched film, and neither cracked when bent. Furthermore, as a result of measuring the mechanical strength of each of these, the tensile breaking strength of the press sheet was 440 kg/a
lf.

Moreover, the elongation was 220%. Furthermore, the biaxially stretched film had a tensile strength at break of 1,600 kg/Ci, an elongation of 165%, and a tensile modulus of 16,000 kg/c/, all of which were almost unchanged compared to before being buried in activated sludge.

Example 2 The raw materials used in the production of the ε-caproate-containing copolyamide were 300 parts by weight of the polycaprolactone of Example 1, 12,600 parts by weight of the nylon of Example 1, and dried at room temperature in the presence of nitrogen gas at a pressure of 300 mmHg and dried. Polyethylene glycol (dried under conditions of 72 hours)
Example 1 except that 100 parts by weight of Mn=400) was used.
An ε-caproate-containing copolyamide was obtained in the same manner as above.

The obtained ε-caproate-containing copolyamide had an intrinsic viscosity [η] of 0.72 dl/g, a glass transition temperature (Tg) of 51°C, and a melting point (Tm) of 167°C.

Next, as in Example 1, 6100 parts by weight of nylon and 30 parts by weight of the above ε-caproate-containing copolyamide were mixed and then melt-extruded at about 230°C using an extruder to produce pellets of the composition. Furthermore, a press sheet having a thickness of about 200 μm was produced by press molding using a pellet of the composition. As a result of measuring the mechanical strength of the obtained press sheet, the tensile strength at break was 450 kg/al.
and elongation was 150%.

Furthermore, this press sheet was biaxially stretched in the same manner as in Example 1 to produce a biaxially stretched film having a thickness of about 22 μm. The mechanical strength was measured and the tensile strength at break was 1470 kg/a1. , tensile elongation 1
20% and a tensile modulus of 16,000 kg/d.

Next, these press sheets and biaxially stretched films were placed in aerobic activated sludge for 12 hours in the same manner as in Example 1.
The specimens were buried for several months and changes in their properties were investigated. As a result, it was found that both the press sheet and the biaxially stretched film cracked and became more brittle when bent.

Furthermore, the mechanical strength of each sheet was measured, and the tensile strength at break of the press sheet was 180 kg/car, and the elongation was 13%. Further, the biaxially stretched film had a tensile strength at break of 340 kg/aI, an elongation of 17%, and a tensile modulus of 14000 kg/ci.

All of these values were significantly lower than the values before being buried in the aerobic activated sludge.

Claims (2)

[Claims] (1) A polyamide resin composition comprising a polyamide and an ε-caproate-containing copolyamide, wherein the ε-caproate-containing copolyamide has (a) a structural unit represented by the following formula [I], and ▲mathematical formula,
There are chemical formulas, tables, etc. ▼... [ I ] (b) The structural unit represented by the following formula [ I ]', and ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼... [ I ]' [However, the formula [ I ]' In, R^0 is at least one group selected from the group consisting of alkylene groups having 2 to 6 carbon atoms, and n is a positive integer of 2 to 100. ] (c) There are structural units represented by the following formula [II] and ▲mathematical formulas, chemical formulas, tables, etc.▼... [II] [However, in formula [II], R^1 has 4 to 10 carbon atoms. is at least one group selected from the group consisting of alkylene group, p-phenylene group, m-phenylene group, 2,6-naphthylene group, and 4,4'-biphenylene group, and R^2 is the number of carbon atoms 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-phenylene dimethylene groups. ] (d) Constituent unit represented by the following formula [III] ▲ Numerical formulas, chemical formulas, tables, etc. are available ▼... [III] [However, in formula [III], R^3 is alkylene having 3 to 11 carbon atoms. At least one group selected from the group consisting of groups. ], and the molar ratio of the (a) structural unit/(b) structural unit is within the range of 100/0 to 50/50, [(a) structural unit + (b) structural unit] / [(c) structural unit + (d) structural unit] molar ratio is 10/90 to 80/
20, and the intrinsic viscosity [η] is 0.2 to 1.5.
dl/g and is a substantially linear copolyamide. (2) A stretched molded article formed from a polyamide resin composition containing a polyamide and an ε-caproate-containing copolyamide, the ε-caproate-containing copolyamide comprising (a) a structural unit represented by the following formula [I] and ▲mathematical formula,
There are chemical formulas, tables, etc. ▼... [ I ] (b) The structural unit represented by the following formula [ I ]', and ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼... [ I ]' [However, the formula [ I ]' In, R^0 is at least one group selected from the group consisting of alkylene groups having 2 to 6 carbon atoms, and n is a positive integer of 2 to 100. ] (c) There are structural units represented by the following formula [II] and ▲mathematical formulas, chemical formulas, tables, etc.▼... [II] [However, in formula [II], R^1 has 4 to 10 carbon atoms. is at least one group selected from the group consisting of alkylene group, p-phenylene group, m-phenylene group, 2,6-naphthylene group, and 4,4'-biphenylene group, and R^2 is the number of carbon atoms 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-phenylene dimethylene groups. ] (d) Constituent unit represented by the following formula [III] ▲ Numerical formulas, chemical formulas, tables, etc. are available ▼... [III] [However, in formula [III], R^3 is alkylene having 3 to 11 carbon atoms. At least one group selected from the group consisting of groups. ], and the molar ratio of the (a) structural unit/(b) structural unit is within the range of 100/0 to 50/50,
The molar ratio of [(a) structural unit + (b) structural unit]/[(c) structural unit + (d) structural unit] is 10/90 to 80/2
0, and the intrinsic viscosity [η] is 0.2 to 1.5 d.
1/g, and is a substantially linear copolyamide.