JPH11246686A - Stretched polyamide film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject film having excellent pinhole resistance, gas barrier property and transparency by melt-extruding a resin mixture comprising a crystalline polyamide and a polyester and having a melt viscosity ratio in a specific range and subsequently stretching the obtained sheet in the longitudinal and latitudinal directions. SOLUTION: This film is obtained by melt-extruding a resin mixture which comprises (A) 95-40 wt.% of a crystalline polyamide obtained from diamines containing >=70 mol.% of meta-xylylene diamine and dicarboxylic acids containing >=70 mol.% of adipic acid and (B) 5-60 wt.% of a polyester obtained from dicarboxylic acids containing >=80 mol.% of terephthalic acid and diols containing >=80 mol.% of ethylene glycol and has a component B/component A melt viscosity ratio of 0.1-3 at 275 deg.C, and subsequently stretching the obtained sheet in the longitudinal and latitudinal directions into lengths of at least 2.0 times, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stretched polyamide film having excellent pinhole resistance, gas barrier properties and transparency.

[0002]

2. Description of the Related Art A stretched film made of polymethaxylylene adipamide (hereinafter sometimes referred to as "nylon MXD6") obtained from adipic acid and meta-xylylenediamine has excellent transparency and heat resistance. Compared to polyethylene terephthalate, nylon 6, etc., they are widely used as packaging films for foods, medicines, cosmetics, etc. because of their excellent gas barrier properties. However, a stretched film made of nylon MXD6 is
For example, when a manufactured film is folded, there is a problem that a minute hole (hereinafter, referred to as a “pinhole”) is easily generated at a bent portion thereof.

Conventionally, to solve this problem, attempts have been made to improve the pinhole resistance of the film by mixing another resin with nylon MXD6. For example,
JP-A-56-62129, JP-B-51-2919.
No. 2 proposes a polyamide film having an improved pinhole resistance, comprising a mixture of a polyamide comprising a mixed xylylenediamine containing meta-xylylenediamine as a main component and an aliphatic dicarboxylic acid, and a nylon 6, and having improved pinhole resistance. I have.

Japanese Patent Application Laid-Open No. 8-165426 discloses a film comprising nylon MXD6, nylon 6 and an ionomer resin, having improved pinhole resistance and tear resistance. However, when nylon MXD6 and an aliphatic polyamide, or nylon MXD6 and an aliphatic polyamide and an ionomer are blended, the pinhole resistance tends to be improved, but the fragrance retention, heat resistance, and ultraviolet blocking properties are reduced. However, it is difficult to say that this method is preferable from the viewpoint that the raw material price is high.

[0005] Apart from these methods, nylon MXD6
It has been attempted to impart pinhole resistance by forming a multilayer structure by co-extrusion or lamination with another resin or the like having good pinhole resistance. For example, JP-A-4-47
Japanese Patent No. 924 discloses a pin-resistant method comprising preparing a laminated film by extruding two or more polyamides selected from an aromatic polyamide containing nylon MXD6, an aliphatic polyamide, or a mixed polyamide thereof in a molten state, and stretching the laminated film. A method for producing a laminated biaxially stretched film with improved hole strength is disclosed. However, improving the mechanical properties of nylon MXD6 by a multilayer structure by coextrusion, lamination, etc. requires special production equipment when supplying a resin or film in addition to general-purpose film production equipment. It is not an industrially advantageous method.

[0006] On the other hand, polyethylene terephthalate has excellent properties such as mechanical properties, heat resistance, fragrance retention, and ultraviolet blocking properties, and is inexpensive, so that it is used as a raw material for films, sheets, containers, fibers and the like. Widely used.
With respect to a film made of a mixture of nylon MXD6 and polyethylene terephthalate, many inventions have been disclosed which attempt to improve the gas barrier properties, film surface properties, abrasion resistance, tear straightness, etc. of polyethylene terephthalate (Japanese Patent Publication No. 53-33618). JP, JP 2-3
8793, JP-B-6-37565, JP-B-7-68374, JP-A-7-188534, and JP-A-8-183092. However,
A packaging film that satisfies all the functions of pinhole resistance, gas barrier property and transparency by mixing polyethylene MXD6 with polyethylene terephthalate is not known.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a stretched polyamide film having excellent pinhole resistance, gas barrier properties and transparency in view of the above-mentioned problems of the prior art.

[0008]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and have found that a diamine containing 70% by mole or more of metaxylylenediamine and 7% of adipic acid.
95 to 40 parts by weight of a crystalline polyamide (A) obtained from a dicarboxylic acid containing 0 mol% or more, and 80 parts by weight of terephthalic acid.
A mixed resin (C) of a dicarboxylic acid containing at least mol% or more and a polyester (B) obtained from a diol containing at least 80 mol% of ethylene glycol having a constant melt viscosity ratio. The inventors have found that a stretched film obtained by molding has excellent pinhole resistance, gas barrier properties and transparency, and have reached the present invention.

That is, the present invention provides the following (1) and (2)
And (3).

(1) A crystalline polyamide (A) 9 obtained from a diamine containing at least 70 mol% of metaxylylenediamine and a dicarboxylic acid containing at least 70 mol% of adipic acid.
Polyester (B) 5 to 60 obtained from 5 to 40% by weight, a dicarboxylic acid containing 80% by mole or more of terephthalic acid, and a diol containing 80% by mole or more of ethylene glycol.
A stretched polyamide film obtained by molding a mixed resin (C) with a weight% (the sum of the weight% is 100% by weight), wherein the crystalline polyamide (A) and the polyester (B) melt at 275 ° C. Viscosity ratio [(Polyester (B)
Melt viscosity / melt viscosity of the crystalline polyamide (A))] is in the range of 0.1 to 3. A sheet obtained by melt-extrusion of the mixed resin (C) has a length of at least 2. A stretched polyamide film having excellent pinhole resistance obtained by stretching the film to 0 times or more.

(2) A crystalline polyamide (A) 9 obtained from a diamine containing at least 70 mol% of metaxylylenediamine and a dicarboxylic acid containing at least 70 mol% of adipic acid.
Polyester (B) 5 to 60 obtained from 5 to 40% by weight, a dicarboxylic acid containing 80% by mole or more of terephthalic acid, and a diol containing 80% by mole or more of ethylene glycol.
A stretched polyamide film obtained by molding a mixed resin (C) with a weight% (the sum of the weight% is 100% by weight), wherein the crystalline polyamide (A) and the polyester (B) melt at 275 ° C. Viscosity ratio [(Polyester (B)
The melt-extruded sheet of the mixed resin (C) whose melt viscosity / melt viscosity of the crystalline polyamide (A) is in the range of 0.1 to 3 is formed in the longitudinal and transverse directions by at least 2.0.
A stretched polyamide film having a number of pinholes of not more than 7/100 cm ² after 400 times of repeated bending fatigue tests of a film having a thickness of 10 to 40 μm and having a thickness of 10 to 40 μm which has been stretched twice or more.

(3) A crystalline polyamide (A) 9 obtained from a diamine containing at least 70 mol% of metaxylylenediamine and a dicarboxylic acid containing at least 70 mol% of adipic acid.
Polyester (B) 5 to 60 obtained from 5 to 40% by weight, a dicarboxylic acid containing 80% by mole or more of terephthalic acid, and a diol containing 80% by mole or more of ethylene glycol.
It is a stretched polyamide film obtained by molding a mixed resin (C) with a weight% (the sum of the weight% is 100% by weight), and is composed of a crystalline polyamide (A) and a polyester (B).
A sheet obtained by melt-extruding a mixed resin (C) having a melt viscosity ratio at 75 ° C. ((melt viscosity of polyester (B) / melt viscosity of crystalline polyamide (A))) in the range of 0.1 to 3 is used. , At least 2.0 each in the vertical and horizontal directions
The number of pinholes of a stretched film having a haze value of 20% or less per 20 μm or less and a stretched film made of the mixed resin (C) after 400 times of repeated bending fatigue tests with a gel botoster. PC
Satisfies the formula (1), wherein the stretched polyamide film has excellent pinhole resistance. PC ≦ 0.5 × PA (1) (PA is 400 times after a repeated bending test of a stretched film of the same thickness obtained by molding using only the crystalline polyamide (A) instead of the mixed resin (C). Indicates the number of pinholes.)

Next, the present invention will be described specifically. The bending fatigue test and the method of measuring the number of pinholes in the present invention are as follows. That is, the stretched film to be subjected to the bending fatigue test is conditioned at 23 ° C. and 50% relative humidity for 7 days or more, cut into a size of 200 mm × 280 mm, and complies with the MIL standard (MIL-B-131C). Gel Botester (Rigaku Kogyo Co., Ltd., Model: No. 901 type)
The film was repeatedly subjected to bending fatigue 400 times in an atmosphere of 23 ° C. and a relative humidity of 50%, after which the film was removed from the gel tester and the number of pinholes was counted.

A poroscope (model: H8e, manufactured by Rigaku Corporation) was used for pinhole measurement. This measurement is
The film after the bending fatigue test is placed on a grounded metal plate, and a voltage of 1.5 kV is applied to the electrode and within a certain area on the film (a range of 20 to 180 mm from the long side of the film and 60 to 220 mm from the short side of the film). Inside, size: 160
mm × 160 mm (area: 256 cm ² ) is scanned (there is a discharge when there is a pinhole, so that the number of pinholes can be measured by measuring the number of discharges).

Since the pinhole resistance is affected by the thickness of the film, the number of pinholes in a stretched film made of only crystalline polyamide is measured with the same thickness as that of the stretched film made of the mixed resin (C). Performed using ones.

The stretched film made of the crystalline polyamide (A) referred to in the present invention is the same as the crystalline polyamide (A) used for mixing with the polyester (B). It refers to a film that has been stretched by the same method as used for forming a stretched film made of the mixed resin (C), and if necessary, has been heat-treated while keeping the film in a tensioned state.

The crystalline polyamide (A) referred to in the present invention is a diamine containing 70 mol%, preferably 80 mol% or more, particularly preferably 90 mol% or more of metaxylylenediamine, and 70 mol% or more of adipic acid. , Preferably 8
It is a crystalline polyamide (A) obtained from a dicarboxylic acid containing at least 0 mol%, particularly preferably at least 90 mol%.

Further, the crystalline polyamide (A) of the present invention may further contain, as other diamine components, paraxylylenediamine, phenylenediamine, 1,4-bis- (2-amino) as long as its properties are not substantially changed. A component unit derived from an aromatic diamine such as ethyl) benzene, ethylenediamine, hexamethylenediamine, pentamethylenediamine, 2,4,4-trimethylhexamethylenediamine, 2,2,4-trimethylhexamethylenediamine, tetramethylene Aliphatic diamines such as diamines,
1,3-bis (aminomethyl) cyclohexane, 1,4
An alicyclic diamine such as -bis (aminomethyl) cyclohexane and bis (4-aminocyclohexyl) methane may be contained in an amount of less than 30 mol%.

On the other hand, in the crystalline polyamide (A) of the present invention, terephthalic acid, isophthalic acid, phthalic acid, and 4,4'-diphenyldicarboxylic acid are used as other dicarboxylic acids within a range that does not substantially change the properties thereof. Aromatic dicarboxylic acids such as 3,4'-diphenyldicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and the like, or Aliphatic dicarboxylic acids such as dodecane diacid, or alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, ε-caprolactam, ω-
It may contain less than 30 mol% of an aminocarboxylic acid such as dicarboxylic acid derived from a lactam such as laurolactam, 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, paraaminomethylbenzoic acid and the like. .

The crystalline polyamide (A) used in the present invention
It is desirable that the polymer be dried to a water content of 0.15% or less, preferably 0.1% or less.

The relative viscosity of the crystalline polyamide (A) used in the present invention (measured at 25 ° C. by dissolving 1 g of polyamide in 100 ml of 96% sulfuric acid) is 1.5 or more, especially 2.0
The above is desirable. When the relative viscosity is 1.5 or more, the molecular weight of the polyamide is sufficiently high, so that a stretched film composed of a mixed resin obtained by using the same has necessary mechanical properties.

The polyester (B) used in the present invention comprises a dicarboxylic acid containing at least 80 mol%, preferably at least 90 mol%, particularly preferably at least 95 mol% of terephthalic acid, and at least 80 mol%, preferably at least 80 mol% of ethylene glycol. A polyester obtained from a diol containing at least 90 mol%, particularly preferably at least 95 mol%.

The polyester (B) used in the present invention is produced by a method of polycondensing a dicarboxylic acid component and a diol component, a transesterification reaction of a polyester homopolymer and / or a copolymer, and the like. In the method of polycondensing a dicarboxylic acid component and a diol component, the dicarboxylic acid component is produced by a conventionally known method such as transesterification using dicarboxylic acid or an ester-forming derivative thereof. Examples of the ester-forming derivatives include ester derivatives such as dimethyl ester and diethyl ester, salts such as diammonium salts, and acid halides such as dichloride.

The polyester (B) used in the present invention includes:
Other dicarboxylic acid components as far as their properties are not substantially changed include phthalic acid, isophthalic acid, 4,4′-diphenyldicarboxylic acid, 3,4′-diphenyldicarboxylic acid, 1,4-naphthalenedicarboxylic acid, A component derived from an aromatic dicarboxylic acid such as 2,5-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, or an ester-forming derivative thereof; Acids, adipic acid, sebacic acid, components derived from aliphatic dicarboxylic acids such as dodecanedioic acid or ester-forming derivatives thereof, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, decalindicarboxylic acids, Alicyclic dicarboxylic acids such as tetralin dicarboxylic acids There may also contain components derived from an ester-forming derivative thereof 20 mol% or less.

The polyester (B) of the present invention further comprises
Component units derived from aliphatic diols such as propylene glycol, trimethylene glycol, diethylene glycol, and 1,4-butanediol as other diol component units as long as their properties are not substantially changed;
A component derived from an alicyclic diol such as 1,4-cyclohexane dimethanol, 1,3-cyclohexane dimethanol, 1,6-cyclohexane diol, and a component derived from an aromatic diol such as bisphenol A Mol% or less may be contained.

The polyester (B) used in the present invention is desirably dried so that the water content in the polymer is 100 ppm or less, more preferably 50 ppm or less.

The limiting viscosity (value measured at 25 ° C. in a phenol / 1,1,2,2-tetrachloroethane = 60/40 weight ratio mixed solvent) of the polyester (B) used in the present invention is 0.3. -2.0 dl / g, especially 0.4-1.8
dl / g is desirable. When the intrinsic viscosity is 0.3 or more, the molecular weight of the polyester is sufficiently high, so that a stretched film made of a mixed resin obtained by using the polyester has the necessary mechanical properties as a film.
On the other hand, when the intrinsic viscosity is 2.0 or less, the mixing property with the crystalline polyamide (A) becomes good.

The above-mentioned polyester (B) has its molecular end sealed by a component derived from a monofunctional compound such as a small amount of benzoic acid, benzoylbenzoic acid, benzyloxybenzoic acid, methoxypolyethylene glycol and the like. You may. Further, it may contain a small amount of a component derived from a polyfunctional compound such as trimellitic acid, pyromellitic acid, glycerin, trimesic acid, and pentaerythritol.

The mixed resin (C) comprising the crystalline polyamide (A) and the polyester (B) of the present invention is used in an amount of 95 to 40 parts by weight, preferably 90 to 40 parts by weight of the crystalline polyamide (A).
Parts by weight and polyester (B) in an amount of 5 to 60 parts by weight, preferably 10 to 60 parts by weight (the sum of the weight percentages is 100% by weight). When the polyester (B) is 5 parts by weight or more, the effect of improving the pinhole resistance of the stretched film made of the mixed resin (C) becomes remarkable,
Equation (1) can be satisfied. When the polyester (B) content is 60 parts by weight or less, the effect of improving pinhole resistance is recognized, and the effect of gas barrier properties can be expected.

The method for producing the stretched film of the present invention is based on the ratio of the melt viscosity of the crystalline polyamide (A) and the polyester (B) at 275 ° C. [melt viscosity of the polyester (B) /
The melt-extruded sheet of the mixed resin (C) having a melt viscosity of the crystalline polyamide (A) in the range of 0.1 to 3 is stretched at least 2.0 times in the longitudinal and transverse directions.
When the stretching ratio is 2.0 times or more, when the film is heated to a glass transition temperature or higher during use or forming after film formation, or during storage under high humidity, or steam treatment for sterilization, hot water It is possible to prevent whitening, crystallization and reduction in transparency when performing a treatment or the like. From a practical point of view, the upper limit of the stretching ratio of the upper sheet is 5 in each of the vertical and horizontal directions.
It is about twice.

In the present invention, the melt viscosity of the crystalline polyamide (A) and the polyester (B) can be measured by a flow tester (manufactured by Shimadzu Corporation, model: CFT-50).
0, die: 1mmφ × 10mm length, extrusion pressure: 10k
gf / cm @ 2) at 275 DEG C.

The ratio of the melt viscosity at 275 ° C. of the crystalline polyamide (A) and the polyester (B) of the present invention [(melt viscosity of polyester (B)) / (melt viscosity of crystalline polyamide (A)] is: 0.1-3, preferably 0.
It is in the range of 1 to 2.5. When the ratio of the melt viscosity is 0.1 or more, when the crystalline polyamide (A) and the polyester (B) are melt-mixed, the mixing of both resins proceeds sufficiently, and a stable film can be produced. In addition, it is possible to prevent the occurrence of excessive surface roughness and thickness unevenness in the film. On the other hand, when the melt viscosity ratio is 3 or less, the transparency of the stretched film composed of the mixed resin (C) of the crystalline polyamide (A) and the polyester (B) is good, and the haze value per 20 μm thickness is 15%. % Or less.

The mixed resin (C) referred to in the present invention is mixed by a conventionally known method. For example, a crystalline polyamide (A) and a polyester (B) are tumbled,
Dry blending with a mold blender, Henschel mixer, etc., melt-kneading at least once with a single-screw extruder, a twin-screw extruder, a kneader or the like can be given. Further, there may be mentioned those obtained by dry-blending or melt-kneading a crystalline polyamide (A), a polyester (B), and a pre-kneaded material obtained by melt-kneading both in advance.

The sheet referred to in the present invention is a substantially unstretched sheet produced by a conventionally known melt extrusion molding method. The thickness of the unstretched sheet is not particularly limited as long as it can be stretched under the stretching conditions of the present invention. The temperature at which the unstretched sheet is melt-extruded using the mixed resin (C) is 220 to 300 ° C, preferably 230 to 300 ° C.
Desirably, it is 290 ° C.

The sheet may be stretched in two directions at the same time using a conventionally known method, for example, a tenter method, a method utilizing the difference in peripheral speed between rolls, or may be sequentially stretched in two directions. May be. In the case of sequentially stretching, any of the longitudinal direction and the transverse direction may be stretched first. Further, a combination of these in several stages may be used. The stretching method is not limited to these, and a conventionally known method such as stretching by a tubular method may be used. Furthermore, the stretched film of the present invention is a conventionally known co-extrusion method,
A method of forming an unstretched sheet with another resin by lamination or the like, and stretching this to form a stretched film may be performed.

Further, as described above, the sheet obtained by melt-extruding the mixed resin (C) has a length of at least 2.0
Stretched more than twice.

The temperature at the time of stretching is higher than that of the crystalline polyamide (A) and the resin having a lower glass transition temperature (hereinafter, referred to as Tg) of the polyester (B), and the resin having the higher Tg. It is preferable that the temperature does not exceed a temperature 40 ° C. higher than the Tg. If the stretching temperature is lower than the above temperature range, the transparency of the film is undesirably reduced. If the stretching temperature exceeds the above range, the crystallization proceeds excessively, and the transparency is undesirably lowered. The stretched film produced by the above method is desirably heat-treated at a temperature not exceeding 10 ° C. higher than the melting point of the crystalline polyamide (A) while keeping the film in a tensioned state. The heat treatment temperature and the heat treatment time are not limited, and are determined by arbitrarily selecting conditions under which a heat shrinkage rate allowed when using the stretched film subjected to the heat treatment is obtained.

The stretched polyamide film obtained by molding the mixed resin (C) thus obtained has excellent pinhole resistance, and the stretched polyamide film having a thickness of 10 to 40 μm can be subjected to a repeated bending fatigue test using a gel botester.
A stretched polyamide film having a pinhole count of 7/100 cm ² or less after rotation is obtained. Furthermore, in the present invention, a stretched polyamide film having a pinhole resistance satisfying the formula (1) after a predetermined repeated bending fatigue test is obtained. Can be

The mixed resin (C) used in the present invention includes a recovered product of polyethylene terephthalate, a recovered product of a modified polyethylene terephthalate product containing a small amount of naphthalene component unit, and a recovered product of polyamide product as long as the properties are not substantially changed. And / or offcuts during the production of molded articles,
And polyester and / or polyamide resin recovered products such as nonstandard products.

In addition to the polyamide and polyester described above, pigments, dyes, lubricants, matting agents, heat stabilizers, and weather stabilizers may be added to the mixed resin of the present invention in addition to the polyamide and polyester described above, as long as the effects of the present invention are not impaired. And additives such as an ultraviolet absorber, a nucleating agent, a plasticizer, a flame retardant, and an antistatic agent.

The stretched film of the present invention may be subjected to a surface treatment such as corona discharge, plasma treatment, chemical treatment, or coating on the entire surface or one surface of the stretched film as long as its properties are not substantially changed.

When using the stretched film according to the present invention, it may be used, for example, as a wrapping film, a packaging bag, a deep drawn product, or the like, or may be laminated with another resin, paper, paper board, or the like to form a laminate. May be used. When using the stretched film of the present invention as a laminate, the total number of layers and the lamination position are not particularly limited, and the stretched film of the present invention may be a surface layer of the laminate, or may be an inner layer. Or may be used for both. The use of the stretched film of the present invention is not limited to these.

[0043]

EXAMPLES The present invention will now be described specifically with reference to examples and comparative examples, but the present invention is not limited to the following examples. The evaluation methods employed in the present example and comparative example are as follows.

(1) Pinhole Resistance The stretched film to be subjected to the bending fatigue test was conditioned for at least 7 days in an atmosphere of 23 ° C. and 50% relative humidity.
It was cut to a size of 80 mm. The cut stretched film was fixed to a gel bot tester (manufactured by Rigaku Kogyo Co., Ltd., No. 901 type) based on the MIL standard (MIL-B-131C).
The film was repeatedly subjected to bending fatigue 400 times in an atmosphere at 50 ° C. and a relative humidity of 50%, and then the film was removed from the gel tester, and the number of pinholes per 256 cm ^{2 of} area was measured. A poroscope (Rigaku Kogyo, H8e type) was used to measure the number of pinholes.

This is because the film subjected to the bending fatigue test is placed on a grounded metal plate, and an electrode to which a voltage of 1.5 kV is applied is applied within a certain area on the film (20 to 20 mm from the long side of the film).
180 mm, within the range of 60 to 220 mm from the short side of the film, size: 160 mm × 160 mm (area: 256 c
m ² )) was scanned to measure the number of pinholes. still,
Since the pinhole resistance depends on the thickness of the film, the pinhole of the stretched film made of the crystalline polyamide (A) and the pinhole of the film made of the mixed resin (C) using the same crystalline polyamide (A) are used. When measuring the numbers, films of equal thickness were used. Tables 1-4
The number of pinholes in the middle is the stretched film area 100 cm ²
The number of pinholes per piece (pieces) is shown, and [(0.5 × PA) -PC] in Tables 1 and 2 indicates that the stretched film area using only the crystalline polyamide (A) in the present invention is 100 cm.
^From the value obtained by multiplying the number of pinholes per ² by 0.5 times, the stretched film area using the mixed resin (C) is 100 cm ^2.
This is a value obtained by reducing the number of pinholes per unit.

(2) Haze value According to JIS-K-7105. As a measuring device, a haze value measuring device (model: COH-300A) manufactured by Nippon Denshoku Industries Co., Ltd. was used.

(3) Oxygen Permeability Coefficient As a measuring device according to ASTM D3985, a device manufactured by Modern Controls (model: OX-TRAN 10 / 50A) was used. Measurement temperature conditions are temperature 23 ° C and relative humidity 60%.
It is.

(4) Melt Viscosity Ratio As a measuring device, a flow tester (model: CFT-500) manufactured by Shimadzu Corporation was used. The measurement conditions are die:
1mmφ × 10mm length, extrusion pressure: 10kgf / cm2
And the measurement temperature is 275 ° C. The melt viscosity ratio is 275 ° C
Of the melt viscosity of the polyester (B) to the melt viscosity of the crystalline polyamide (A) [(melt viscosity of polyester (B)) / (melt viscosity of crystalline polyamide (A)]
It was calculated as

Example 1 Nylon MXD6 (manufactured by Mitsubishi Gas Chemical Co., Ltd., relative viscosity: 2.2, melt viscosity: 214 Pa) as a crystalline polyamide
S, hereinafter sometimes referred to as “PA1”) and polyethylene terephthalate as polyester (hereinafter “PE1”).
T ”, manufactured by Nihon Unipet Co., Ltd., trade name: UNI
PET, grade: RT543C, melt viscosity: 417P
The dried pellets of a · s) were mixed by a tumbler, and the blending ratio (nylon MXD6 / PET, weight ratio)
Is 90/10 mixed pellets (melt viscosity ratio: 1.95)
Was prepared. This mixed pellet is fed to a single screw extruder (screw shape: full flight, screw diameter: 20 mmφ,
L / D: 25), a film was formed by a T-die method under the conditions of a cylinder temperature of 275 to 275 ° C, a T-die temperature of 280 ° C, a screw rotation speed of 72 rpm, and a cooling roll temperature of 80 ° C. A 0.3 mm unstretched sheet was obtained.

Next, after preheating the above unstretched sheet at 90 to 100 ° C. for 30 seconds using a biaxial stretching machine manufactured by Toyo Seiki Co., Ltd., a linear stretching speed of 87% / sec and a stretching ratio in the longitudinal and transverse directions. Were stretched simultaneously in the longitudinal and transverse directions under the conditions of 4.0 times each. Next, the stretched film was subjected to a heat treatment in an atmosphere at 235 to 240 ° C. for 5 seconds while keeping the stretched state, to obtain a stretched film having a thickness of 20 μm. Table 1 shows the measurement results of the haze value, the number of pinholes, and the oxygen permeability coefficient of the obtained film. In addition, by the same method, a thickness of 0.2
mm, and stretched unstretched film having a thickness of 0.3 mm in the longitudinal and transverse directions at 4.4 times and 3.5 times, respectively.
A stretched film having a thickness of 10 μm and 25 μm was obtained. As a result, the obtained films had haze values of 1.9% and 4.6, respectively.
%, Number of pinholes 4.3 / 100 cm ² , 5.5 /
100 cm ² , and oxygen permeability coefficient is 0.05 (cc-mm /
m ² -day-atm) and 0.05 (cc-mm / m ² -day-atm).

Example 2 Nylon MXD6 (Mitsubishi Gas Chemical Co., Ltd., trade name: M
X nylon, grade name: 6007, relative viscosity: 2.
7. Dry pellets of melt viscosity: 530 Pa · s (hereinafter sometimes referred to as “PA2”) and PET (UNIPET, manufactured by Nippon Unipet Co., Ltd., grade: RT543C, melt viscosity: 417 Pa · s) Are mixed by a tumbler, and the blend ratio (nylon MXD6 / PE
(T, weight ratio) of 90/10 was prepared as a mixed pellet (melt viscosity ratio: 0.79). Using a twin screw extruder (screw diameter: 20 mmφ, L / D: 25), the mixed pellet was subjected to a T-die method at a cylinder temperature of 265 to 275.
℃, T die temperature 275 ℃, screw rotation speed 100rpm
m, forming a film under the condition of a cooling roll temperature of 80 ° C.
An unstretched sheet having a thickness of about 0.3 mm was obtained.

Next, the above unstretched sheet was preheated at 90 to 100 ° C. for 30 seconds using a biaxial stretching machine manufactured by Toyo Seiki Co., Ltd., and then a linear stretching speed of 87% / sec and a stretching ratio in the longitudinal and transverse directions were applied. Were stretched simultaneously in the longitudinal and transverse directions under the conditions of 4.0 times each. Next, the stretched film was subjected to a heat treatment in an atmosphere at 235 to 240 ° C. for 5 seconds while keeping the stretched state, to obtain a stretched film having a thickness of 20 μm. Table 1 shows the measurement results of the haze value, the number of pinholes, and the oxygen permeability coefficient of the obtained film.

Example 3 Nylon MXD6 (manufactured by Mitsubishi Gas Chemical Co., Ltd., relative viscosity:
2.2, melt viscosity: 214 Pa · s) and PET (manufactured by Nippon Unipet Co., Ltd., trade name: UNIPET, grade:
Dry pellets of RT543C (melt viscosity: 417 Pa · s) were mixed by a tumbler to prepare mixed pellets (melt viscosity ratio: 1.95) having a blend ratio (nylon MXD6 / PET, weight ratio) of 80/20. This mixed pellet is subjected to a twin-screw extruder (screw diameter: 20 mmφ,
L / D: 25), a film was formed by a T-die method under the conditions of a cylinder temperature of 265 to 275 ° C, a T-die temperature of 275 ° C, a screw rotation speed of 100 rpm, and a cooling roll temperature of 80 ° C. A 0.3 mm unstretched sheet was obtained.

Next, after preheating the above unstretched sheet at 90 to 100 ° C. for 30 seconds using a biaxial stretching machine manufactured by Toyo Seiki Co., Ltd., a linear stretching speed of 87% / sec and a stretching ratio in the longitudinal and transverse directions. Were stretched simultaneously in the longitudinal and transverse directions under the conditions of 4.0 times each. Next, the stretched film was subjected to a heat treatment in an atmosphere at 235 to 240 ° C. for 5 seconds while keeping the stretched state, to obtain a stretched film having a thickness of 20 μm. Table 1 shows the measurement results of the haze value, the number of pinholes, and the oxygen permeability coefficient of the obtained film.

Example 4 Nylon MXD6 (Mitsubishi Gas Chemical Co., Ltd., trade name: M
X nylon, grade name: 6007, relative viscosity: 2.
7, melt viscosity: 530 Pa · s) and PET (manufactured by Nippon Unipet Co., Ltd., trade name: UNIPET, grade: RT)
Dried pellets having a melt viscosity of 543 C (417 Pa · s) were mixed by a tumbler to prepare a mixed pellet (melt viscosity ratio: 0.79) having a blend ratio (nylon MXD6 / PET, weight ratio) of 80/20.

This mixed pellet was subjected to a single screw extruder (screw shape: full flight, screw diameter: 20 mmφ,
L / D: 25), a film was formed by the T-die method under the conditions of a cylinder temperature of 275 to 275 ° C., a T-die temperature of 280 ° C., a screw rotation speed of 72 rpm, and a cooling roll temperature of 80 ° C. A 0.3 mm unstretched sheet was obtained.

Next, after preheating the unstretched sheet at 95 to 105 ° C. for 30 seconds using a biaxial stretching machine manufactured by Toyo Seiki Co., Ltd., a linear stretching speed of 87% / sec, and a stretching ratio in the longitudinal and transverse directions. Were stretched simultaneously in the longitudinal and transverse directions under the conditions of 4.0 times each. Next, the stretched film was subjected to a heat treatment in an atmosphere at 235 to 240 ° C. for 5 seconds while keeping the stretched state, to obtain a stretched film having a thickness of 20 μm. Table 1 shows the measurement results of the haze value, the number of pinholes, and the oxygen permeability coefficient of the obtained film.

Example 5 Nylon MXD6 (trade name: M, manufactured by Mitsubishi Gas Chemical Co., Ltd.)
X nylon, grade name: 6121, relative viscosity: 3.
5. Melt viscosity: 2300 Pa · s (hereinafter may be referred to as “PA3”) and dried pellets of PET (manufactured by Nippon Unipet Co., Ltd., trade name: UNIPET, grade: RT543C, melt viscosity: 417 Pa · s) Are mixed by a tumbler, and the blend ratio (nylon MXD6 / PE
(T, weight ratio) 80/20 (melt viscosity ratio: 0.18) was prepared.

Using a twin screw extruder (screw diameter: 20 mmφ, L / D: 25), the mixed pellet was subjected to a T-die method at a cylinder temperature of 265 to 275 ° C. and a T-die temperature of 2
The film was formed under the conditions of 75 ° C., a screw rotation speed of 100 rpm, and a cooling roll temperature of 80 ° C., with a width of 120 mm and a thickness of about 0.2 mm.
A 3 mm unstretched sheet was obtained.

Next, after preheating the above unstretched sheet at 95 to 105 ° C. for 30 seconds using a biaxial stretching machine manufactured by Toyo Seiki Co., Ltd., a linear stretching speed of 87% / sec, and a stretching ratio in the longitudinal and transverse directions. Were stretched simultaneously in the longitudinal and transverse directions under the conditions of 4.0 times each. Next, the stretched film was subjected to a heat treatment in an atmosphere at 235 to 240 ° C. for 5 seconds while keeping the stretched state, to obtain a stretched film having a thickness of 20 μm. Table 1 shows the measurement results of the haze value, the number of pinholes, and the oxygen permeability coefficient of the obtained film.

Example 6 Nylon MXD6 (manufactured by Mitsubishi Gas Chemical Co., Ltd., relative viscosity:
2.2, melt viscosity: 214 Pa · s) and PET (manufactured by Nippon Unipet Co., Ltd., trade name: UNIPET, grade:
Dry pellets of RT543C (melt viscosity: 417 Pa · s) were mixed by a tumbler to prepare mixed pellets (melt viscosity ratio: 1.95) having a blend ratio (nylon MXD6 / PET, weight ratio) of 60/40.

This mixed pellet was fed to a single screw extruder (screw shape: full flight, screw diameter: 20 mmφ,
L / D: 25), a film was formed by the T-die method under the conditions of a cylinder temperature of 275 to 275 ° C., a T-die temperature of 280 ° C., a screw rotation speed of 72 rpm, and a cooling roll temperature of 80 ° C. A 0.3 mm unstretched sheet was obtained.

Next, after preheating the above unstretched sheet at 95 to 105 ° C. for 30 seconds using a biaxial stretching machine manufactured by Toyo Seiki Co., Ltd., a linear stretching rate of 87% / sec, and a stretching ratio in the longitudinal and transverse directions. Were stretched simultaneously in the longitudinal and transverse directions under the conditions of 4.0 times each. Next, the stretched film was subjected to a heat treatment in an atmosphere at 235 to 240 ° C. for 5 seconds while keeping the stretched state, to obtain a stretched film having a thickness of 20 μm. Table 1 shows the measurement results of the haze value, the number of pinholes, and the oxygen permeability coefficient of the obtained film.

Example 7 Nylon MXD6 (trade name: M, manufactured by Mitsubishi Gas Chemical Co., Ltd.)
X nylon, grade name: 6007, relative viscosity: 2.
7, melt viscosity: 530 Pa · s) and PET (manufactured by Nippon Unipet Co., Ltd., trade name: UNIPET, grade: RT)
Dried pellets having a melt viscosity of 543 C (417 Pa · s) were mixed by a tumbler to prepare mixed pellets (melt viscosity ratio: 0.79) having a blend ratio (nylon MXD6 / PET, weight ratio) of 60/40.

This mixed pellet was fed to a single screw extruder (screw shape: full flight, screw diameter: 20 mmφ,
L / D: 25), a film was formed by the T-die method under the conditions of a cylinder temperature of 275 to 275 ° C., a T-die temperature of 280 ° C., a screw rotation speed of 72 rpm, and a cooling roll temperature of 80 ° C. A 0.3 mm unstretched sheet was obtained.

Next, after preheating the above unstretched sheet at 95 to 105 ° C. for 30 seconds using a biaxial stretching machine manufactured by Toyo Seiki Co., Ltd., a linear stretching speed of 87% / sec, and a stretching ratio in the longitudinal and transverse directions. Were stretched simultaneously in the longitudinal and transverse directions under the conditions of 4.0 times each. Next, the stretched film was subjected to a heat treatment in an atmosphere at 235 to 240 ° C. for 5 seconds while keeping the stretched state, to obtain a stretched film having a thickness of 20 μm. Table 2 shows the measurement results of the haze, the number of pinholes, and the oxygen permeability coefficient of the obtained film.

Example 8 Nylon MXD6 (trade name: M, manufactured by Mitsubishi Gas Chemical Co., Ltd.)
X nylon, grade name: 6121, relative viscosity: 3.
5, melt viscosity: 2300 Pa · s) and PET (manufactured by Nippon Unipet Co., Ltd., trade name: UNIPET, grade: R
The dried pellets (T543C, melt viscosity: 417 Pa · s) were mixed by a tumbler to prepare a mixed pellet (melt viscosity ratio: 0.18) having a blend ratio (nylon MXD6 / PET, weight ratio) of 60/40.

Using a twin screw extruder (screw diameter: 20 mmφ, L / D: 25), the mixed pellet was subjected to a T-die method at a cylinder temperature of 265 to 275 ° C. and a T-die temperature of 2
The film was formed under the conditions of 75 ° C., a screw rotation speed of 100 rpm, and a cooling roll temperature of 80 ° C., with a width of 120 mm and a thickness of about 0.2 mm.
A 3 mm unstretched sheet was obtained.

Next, after preheating the above unstretched sheet at 95 to 105 ° C. for 30 seconds using a biaxial stretching machine manufactured by Toyo Seiki Co., Ltd., a linear stretching speed of 87% / sec, and a stretching ratio in the longitudinal and transverse directions. Were stretched simultaneously in the longitudinal and transverse directions under the conditions of 4.0 times each. Next, the stretched film was subjected to a heat treatment in an atmosphere at 235 to 240 ° C. for 5 seconds while keeping the stretched state, to obtain a stretched film having a thickness of 20 μm. Table 2 shows the measurement results of the haze, the number of pinholes, and the oxygen permeability coefficient of the obtained film.

Example 9 Nylon MXD6 (manufactured by Mitsubishi Gas Chemical Co., Ltd., relative viscosity:
2.2, melt viscosity: 214 Pa · s) and PET (manufactured by Nippon Unipet Co., Ltd., trade name: UNIPET, grade:
Dry pellets of RT543C (melt viscosity: 417 Pa · s) were mixed by a tumbler to prepare mixed pellets (melt viscosity ratio: 1.95) having a blend ratio (nylon MXD6 / PET, weight ratio) of 40/60.

This mixed pellet was fed to a single screw extruder (screw shape: full flight, screw diameter: 20 mmφ,
L / D: 25), a film was formed by a T-die method under the conditions of a cylinder temperature of 275 to 275 ° C., a T-die temperature of 280 ° C., a screw rotation speed of 72 rpm, and a cooling roll temperature of 70 ° C. A 0.3 mm unstretched sheet was obtained.

Next, after preheating the above unstretched sheet at 95 to 105 ° C. for 30 seconds using a biaxial stretching machine manufactured by Toyo Seiki Co., Ltd., a linear stretching speed of 87% / sec, and a stretching ratio in the longitudinal and transverse directions. Were stretched simultaneously in the longitudinal and transverse directions under the conditions of 4.0 times each. Next, the stretched film was subjected to a heat treatment in an atmosphere at 235 to 240 ° C. for 5 seconds while keeping the stretched state, to obtain a stretched film having a thickness of 20 μm. Table 2 shows the measurement results of the haze, the number of pinholes, and the oxygen permeability coefficient of the obtained film.

Example 10 Nylon MXD6 (trade name: M, manufactured by Mitsubishi Gas Chemical Co., Ltd.)
X nylon, grade name: 6007, relative viscosity: 2.
7, melt viscosity: 530 Pa · s) and PET (manufactured by Nippon Unipet Co., Ltd., trade name: UNIPET, grade: RT)
The dried pellets having a melt viscosity of 543 C and a melt viscosity of 417 Pa · s were mixed by a tumbler to prepare a mixed pellet (melt viscosity ratio: 0.79) having a blend ratio (nylon MXD6 / PET, weight ratio) of 40/60.

This mixed pellet was fed to a single screw extruder (screw shape: full flight, screw diameter: 20 mmφ,
L / D: 25), a film was formed by a T-die method under the conditions of a cylinder temperature of 275 to 275 ° C., a T-die temperature of 280 ° C., a screw rotation speed of 72 rpm, and a cooling roll temperature of 70 ° C. A 0.3 mm unstretched sheet was obtained.

Next, the above-mentioned unstretched film was preheated at 95 to 105 ° C. for 30 seconds using a biaxial stretching machine manufactured by Toyo Seiki Co., Ltd., and then a linear stretching speed of 87% / sec and a stretching ratio in the longitudinal and transverse directions. Were stretched simultaneously in the longitudinal and transverse directions under the conditions of 4.0 times each. Next, the stretched film was subjected to a heat treatment in an atmosphere at 235 to 240 ° C. for 5 seconds while keeping the stretched state, to obtain a stretched film having a thickness of 20 μm. Table 2 shows the measurement results of the haze, the number of pinholes, and the oxygen permeability coefficient of the obtained film.

Example 11 Nylon MXD6 (trade name: M, manufactured by Mitsubishi Gas Chemical Co., Ltd.)
X nylon, grade name: 6121, relative viscosity: 3.
5, melt viscosity: 2300 Pa · s) and PET (manufactured by Nippon Unipet Co., Ltd., trade name: UNIPET, grade: R
T543C, dried pellets having a melt viscosity of 417 Pa · s) were mixed by a tumbler to prepare a mixed pellet (melt viscosity ratio: 0.18) having a blend ratio (nylon MXD6 / PET, weight ratio) of 40/60.

Using a twin screw extruder (screw diameter: 20 mmφ, L / D: 25), the mixed pellet was subjected to a T-die method at a cylinder temperature of 265 to 275 ° C. and a T-die temperature of 2
The film was formed under the conditions of 75 ° C., a screw rotation speed of 100 rpm, and a cooling roll temperature of 70 ° C., with a width of 120 mm and a thickness of about 0.2 mm.
A 3 mm unstretched sheet was obtained. Next, using a biaxial stretching machine manufactured by Toyo Seiki Co., Ltd.,
After preheating at 30 ° C. for 30 seconds, the linear stretching speed was 87% / sec.
The film was simultaneously stretched in the machine and transverse directions under the conditions that the stretching ratio in the machine and transverse directions was 4.0 times each. Next, the stretched film was subjected to a heat treatment in an atmosphere at 235 to 240 ° C. for 5 seconds while keeping the stretched state, to obtain a stretched film having a thickness of 20 μm. Table 2 shows the measurement results of the haze, the number of pinholes, and the oxygen permeability coefficient of the obtained film.

Comparative Example 1 Nylon MXD6 (manufactured by Mitsubishi Gas Chemical Co., Ltd., relative viscosity:
2.2) The pellets obtained above were subjected to a twin-screw extruder (screw diameter: 2).
0 mmφ, L / D: 25), a film was formed by the T-die method under the conditions of a cylinder temperature of 260 to 270 ° C., a T-die temperature of 270 ° C., a screw rotation speed of 100 rpm, and a cooling roll temperature of 80 ° C. An unstretched sheet having a thickness of about 0.3 mm was obtained.

Next, after preheating the above unstretched sheet at 90 to 100 ° C. for 30 seconds using a biaxial stretching machine manufactured by Toyo Seiki Co., Ltd., a linear stretching speed of 87% / sec, and a stretching ratio in the longitudinal and transverse directions. Were stretched simultaneously in the longitudinal and transverse directions under the conditions of 4.0 times each. Next, the stretched film was subjected to a heat treatment in an atmosphere at 235 to 240 ° C. for 5 seconds while keeping the stretched state, to obtain a stretched film having a thickness of 20 μm. Table 3 shows the measurement results of the haze value, the number of pinholes, and the oxygen permeability coefficient of the obtained film.

Comparative Example 2 Nylon MXD6 (Mitsubishi Gas Chemical Co., Ltd., trade name: M
X nylon, grade name: 6007, relative viscosity: 2.
The pellet of 7) is converted into a single screw extruder (screw shape: full flight, screw diameter: 20 mmφ, L / D: 25).
And a cylinder temperature of 260 to 270 by a T-die method.
° C, T-die temperature 270 ° C, screw rotation speed 72 rpm
m, forming a film under the condition of a cooling roll temperature of 80 ° C.
An unstretched sheet having a thickness of about 0.3 mm was obtained.

Next, using a biaxial stretching machine manufactured by Toyo Seiki Co., Ltd., the above unstretched sheet was preheated at 90 to 100 ° C. for 30 seconds, and then a linear stretching speed of 87% / sec and a stretching ratio in the longitudinal and transverse directions. Were stretched simultaneously in the longitudinal and transverse directions under the conditions of 4.0 times each. Next, the stretched film was subjected to a heat treatment in an atmosphere at 235 to 240 ° C. for 5 seconds while keeping the stretched state, to obtain a stretched film having a thickness of 20 μm. Table 3 shows the measurement results of the haze value, the number of pinholes, and the oxygen permeability coefficient of the obtained film.

Comparative Example 3 Nylon MXD6 (Mitsubishi Gas Chemical Co., Ltd., trade name: M
X nylon, grade name: 6121, relative viscosity: 3.
5) The pellets obtained above were subjected to a twin-screw extruder (screw diameter: 20 m).
mφ, L / D: 25), and a film was formed by a T-die method under the conditions of a cylinder temperature of 265 to 275 ° C, a T-die temperature of 275 ° C, a screw rotation speed of 100 rpm, and a cooling roll temperature of 80 ° C. An unstretched sheet having a thickness of about 0.3 mm was obtained.

Next, after preheating the above unstretched sheet at 95 to 105 ° C. for 30 seconds using a biaxial stretching machine manufactured by Toyo Seiki Co., Ltd., a linear stretching speed of 87% / sec, and a stretching ratio in the longitudinal and transverse directions. Were stretched simultaneously in the longitudinal and transverse directions under the conditions of 4.0 times each. Next, the stretched film was subjected to a heat treatment in an atmosphere at 235 to 240 ° C. for 5 seconds while keeping the stretched state, to obtain a stretched film having a thickness of 20 μm. Table 3 shows the measurement results of the haze value, the number of pinholes, and the oxygen permeability coefficient of the obtained film.

Comparative Example 4 Nylon MXD6 (manufactured by Mitsubishi Gas Chemical Co., Ltd., relative viscosity:
2.2, melt viscosity: 214 Pa · s) and PET (manufactured by Nippon Unipet Co., Ltd., trade name: UNIPET, grade:
Dry pellets of RT543C (melt viscosity: 417 Pa · s) were mixed by a tumbler to prepare mixed pellets (melt viscosity ratio: 1.95) having a blend ratio (nylon MXD6 / PET, weight ratio) of 98/2.

This mixed pellet was fed to a single screw extruder (screw shape: full flight, screw diameter: 20 mmφ,
L / D: 25), a film was formed by the T-die method under the conditions of a cylinder temperature of 275 to 275 ° C., a T-die temperature of 280 ° C., a screw rotation speed of 72 rpm, and a cooling roll temperature of 80 ° C. A 0.3 mm unstretched sheet was obtained.

Next, after preheating the above unstretched sheet at 90 to 100 ° C. for 30 seconds using a biaxial stretching machine manufactured by Toyo Seiki Co., Ltd., a linear stretching speed of 87% / sec, and a stretching ratio in the longitudinal and transverse directions. Were stretched simultaneously in the longitudinal and transverse directions under the conditions of 4.0 times each. Next, the stretched film was subjected to a heat treatment in an atmosphere at 235 to 240 ° C. for 5 seconds while keeping the stretched state, to obtain a stretched film having a thickness of 20 μm. Table 3 shows the measurement results of the haze value, the number of pinholes, and the oxygen permeability coefficient of the obtained film. Since the obtained stretched film had a small amount of PET mixed, the effect of improving pinholes was clearly insufficient.

Comparative Example 5 Nylon MXD6 (Mitsubishi Gas Chemical Co., Ltd., trade name: M
X nylon, grade name: 6121, relative viscosity: 3.
5, melt viscosity: 2300 Pa · s) and PET (manufactured by Nippon Unipet Co., Ltd., trade name: UNIPET, grade: R
T543C, dried pellets having a melt viscosity of 417 Pa · s) were mixed by a tumbler to prepare a mixed pellet (melt viscosity ratio: 0.18) having a blend ratio (nylon MXD6 / PET, weight ratio) of 98/2.

Using a twin screw extruder (screw diameter: 20 mmφ, L / D: 25), the mixed pellet was subjected to a T-die method at a cylinder temperature of 265 to 275 ° C. and a T-die temperature of 2
The film was formed under the conditions of 75 ° C., a screw rotation speed of 100 rpm, and a cooling roll temperature of 80 ° C., with a width of 120 mm and a thickness of about 0.2 mm.
A 3 mm unstretched sheet was obtained.

Next, after preheating the above unstretched sheet at 95 to 105 ° C. for 30 seconds using a biaxial stretching machine manufactured by Toyo Seiki Co., Ltd., a linear stretching speed of 87% / sec and a stretching ratio in the longitudinal and transverse directions. Were stretched simultaneously in the longitudinal and transverse directions under the conditions of 4.0 times each. Next, the stretched film was subjected to a heat treatment in an atmosphere at 235 to 240 ° C. for 5 seconds while keeping the stretched state, to obtain a stretched film having a thickness of 20 μm. Table 3 shows the measurement results of the haze value, the number of pinholes, and the oxygen permeability coefficient of the obtained film. Since the obtained stretched film had a small amount of PET mixed, the effect of improving pinholes was clearly insufficient.

Comparative Example 6 Nylon MXD6 (manufactured by Mitsubishi Gas Chemical Co., Ltd., relative viscosity:
2.2, melt viscosity: 214 Pa · s) and PET (manufactured by Kanebo Co., Ltd., trade name: Bellpet, grade: EFG85)
A, Melt viscosity: 893 Pa · s), dried pellets were mixed by a tumbler, and the blend ratio (nylon MXD
6 / PET (weight ratio): 80/20 (melt viscosity ratio: 4.17) was prepared. This mixed pellet is subjected to a twin-screw extruder (screw diameter: 20 mmφ, L / D:
25), using a T-die method, cylinder temperature 265
275 ° C, T-die temperature 275 ° C, screw rotation speed 10
A film was formed under the conditions of 0 rpm and a cooling roll temperature of 80 ° C. to obtain an unstretched sheet having a width of 120 mm and a thickness of about 0.3 mm.

Next, after preheating the above unstretched sheet at 95 to 105 ° C. for 30 seconds using a biaxial stretching machine manufactured by Toyo Seiki Co., Ltd., a linear stretching speed of 87% / sec, and a stretching ratio in the longitudinal and transverse directions. Were stretched simultaneously in the longitudinal and transverse directions under the conditions of 4.0 times each. Next, the stretched film was subjected to a heat treatment in an atmosphere at 235 to 240 ° C. for 5 seconds while keeping the stretched state, to obtain a stretched film having a thickness of 20 μm. Table 4 shows the measurement results of the haze, the number of pinholes, and the oxygen permeability coefficient of the obtained film. Since the film obtained from Table 4 exceeded the range of the melt viscosity ratio of the present invention, the transparency was insufficient for use as a packaging film.

Comparative Example 7 Nylon MXD6 (manufactured by Mitsubishi Gas Chemical Co., Ltd., relative viscosity:
2.2, melt viscosity: 214 Pa · s) and PET (manufactured by Kanebo Co., Ltd., trade name: Bellpet, grade: EFG85)
A, Melt viscosity: 893 Pa · s), dried pellets were mixed by a tumbler, and the blend ratio (nylon MXD
A mixed pellet (melt viscosity ratio: 4.17) having a ratio of 6 / PET (weight ratio: 60/40) was prepared. Using a single screw extruder (screw shape: full flight, screw diameter: 20 mmφ, L / D: 25), the mixed pellet was subjected to T-die method at a cylinder temperature of 275 to 275 ° C, a T-die temperature of 280 ° C, and a screw rotation speed. The film was formed under the conditions of 72 rpm and a cooling roll temperature of 80 ° C., with a width of 120 mm and a thickness of about 0.2 mm.
A 3 mm unstretched sheet was obtained.

Next, after preheating the above unstretched sheet at 95 to 105 ° C. for 30 seconds using a biaxial stretching machine manufactured by Toyo Seiki Co., Ltd., a linear stretching speed of 87% / sec, and a stretching ratio in the longitudinal and transverse directions. Were stretched simultaneously in the longitudinal and transverse directions under the conditions of 4.0 times each. Next, the stretched film was subjected to a heat treatment in an atmosphere at 235 to 240 ° C. for 5 seconds while keeping the stretched state, to obtain a stretched film having a thickness of 20 μm. Table 4 shows the measurement results of the haze, the number of pinholes, and the oxygen permeability coefficient of the obtained film. Since the film obtained from Table 4 exceeded the range of the melt viscosity ratio of the present invention, the transparency was insufficient for use as a packaging film.

Comparative Example 8 Nylon MXD6 (manufactured by Mitsubishi Gas Chemical Co., Ltd., relative viscosity:
2.2, melt viscosity: 214 Pa · s) and PET (manufactured by Nippon Unipet Co., Ltd., trade name: UNIPET, grade:
Dry pellets of RT580C (melt viscosity: 1918 Pa · s) were mixed by a tumbler to prepare mixed pellets (melt viscosity ratio: 8.96) having a blend ratio (nylon MXD6 / PET, weight ratio) of 60/40. This mixed pellet is subjected to a twin screw extruder (screw diameter: 20 mm
φ, L / D: 25), a film was formed by a T-die method under the conditions of a cylinder temperature of 270 to 280 ° C., a T-die temperature of 280 ° C., a screw rotation speed of 100 rpm, and a cooling roll temperature of 80 ° C. An unstretched sheet having a thickness of about 0.3 mm was obtained.

Next, after preheating the above unstretched sheet at 95 to 105 ° C. for 30 seconds using a biaxial stretching machine manufactured by Toyo Seiki Co., Ltd., a linear stretching speed of 87% / sec, and a stretching ratio in the longitudinal and transverse directions. Were stretched simultaneously in the longitudinal and transverse directions under the conditions of 4.0 times each. Next, the stretched film was subjected to a heat treatment in an atmosphere at 235 to 240 ° C. for 5 seconds while keeping the stretched state, to obtain a stretched film having a thickness of 20 μm. Table 4 shows the measurement results of the haze, the number of pinholes, and the oxygen permeability coefficient of the obtained film. Since the film obtained from Table 4 exceeded the range of the melt viscosity ratio of the present invention, the transparency was insufficient for use as a packaging film.

Comparative Example 9 Nylon MXD6 (Mitsubishi Gas Chemical Co., Ltd., trade name: M
X nylon, grade name: 6121, relative viscosity: 3.
5, melt viscosity: 2300 Pa · s) and PET (IV.
= 0.5, melt viscosity: 190 Pa · s), and mixed with a tumbler to obtain a mixed pellet (melt viscosity ratio: 0.08) having a blend ratio (nylon MXD6 / PET, weight ratio) of 40/60. Got ready. This mixed pellet is supplied to a twin-screw extruder (screw diameter: 20 mmφ, L /
D: 25) and the cylinder temperature 26 by the T-die method.
A film was formed under the conditions of 5 to 275 ° C., a T-die temperature of 275 ° C., a screw rotation speed of 100 rpm, and a cooling roll temperature of 70 ° C. to obtain an unstretched sheet having a width of 120 mm and a thickness of about 0.3 mm.

Next, after preheating the above unstretched sheet at 95 to 105 ° C. for 30 seconds using a biaxial stretching machine manufactured by Toyo Seiki Co., Ltd., a linear stretching speed of 87% / sec, and a stretching ratio in the longitudinal and transverse directions. Were stretched simultaneously in the longitudinal and transverse directions under the conditions of 4.0 times each. However, since the obtained film was in a poorly mixed state of MX nylon and PET, unevenness in thickness and surface roughness were remarkable, and no evaluable film was obtained.

Comparative Example 10 Nylon MXD6 (trade name: M, manufactured by Mitsubishi Gas Chemical Co., Ltd.)
X nylon, grade name: 6007, relative viscosity: 2.
7, melt viscosity: 530 Pa · s) and PET (manufactured by Nippon Unipet Co., Ltd., trade name: UNIPET, grade: RT)
Dried pellets having a melt viscosity of 543 C and a melt viscosity of 417 Pa · s were mixed by a tumbler to prepare a mixed pellet (melt viscosity ratio: 0.79) having a blend ratio (nylon MXD6 / PET, weight ratio) of 20/80. This mixed pellet is fed to a single screw extruder (screw shape: full flight,
Screw diameter: 20 mmφ, L / D: 25), T
A film was formed by a die method under the conditions of a cylinder temperature of 275 to 275 ° C., a T-die temperature of 280 ° C., a screw rotation speed of 72 rpm, and a cooling roll temperature of 70 ° C., to obtain an unstretched sheet having a width of 120 mm and a thickness of about 0.3 mm. .

Next, after preheating the above unstretched sheet at 95 to 105 ° C. for 30 seconds using a biaxial stretching machine manufactured by Toyo Seiki Co., Ltd., a linear stretching speed of 87% / sec, and a stretching ratio in the longitudinal and transverse directions. Were stretched simultaneously in the longitudinal and transverse directions under the conditions of 4.0 times each. Next, the stretched film was subjected to a heat treatment in an atmosphere at 235 to 240 ° C. for 5 seconds while keeping the stretched state, to obtain a stretched film having a thickness of 20 μm. Table 4 shows the measurement results of the haze, the number of pinholes, and the oxygen permeability coefficient of the obtained film. The film obtained from Table 4 was used as a packaging film for the purpose of preventing deterioration of contents such as food at a practical thickness due to reduced oxygen barrier property, although the effect of improving transparency and pinholes was recognized. Not suitable.

[0100]

[Table 1] Example No. 1 2 3 4 5 6 Resin used Polyamide used PA1 PA2 PA1 PA2 PA3 PA1 PET mixed amount (parts by weight) 10 10 20 20 20 40 Melt viscosity ratio 1.95 0.79 1.95 0.79 0.18 1.95 Number of pinholes (pieces) ) ^* 5.1 4.7 3.9 3.5 2.8 2.7 (0.5 x PA)-PC (pcs) ^* 0.4 0.6 1.6 1.8 2.1 2.7 Haze (%) 4.0 2.7 5.3 3.4 3.0 7.1 Oxygen transmission coefficient 0.05 0.05 0.07 0.06 0.06 0.08 (cc-mm / m ² -day-atm) * Number of pinholes per 100 cm ^{2 of} stretched film area.

[0101]

[Table 2] Example No. 7 8 9 10 11 Resin used Polyamide used PA2 PA3 PA1 PA2 PA3 PET mixing amount (parts by weight) 40 40 60 60 60 Melt viscosity ratio 0.79 0.18 1.95 0.79 0.18 Number of pinholes (pieces) ^* 2.3 1.6 3.1 2.0 1.2 (0.5 x PA)-PC (pcs) ^* 2.9 3.3 2.3 3.3 3.7 Haze (%) 4.5 4.7 7.5 8.0 6.1 Oxygen permeability coefficient 0.07 0.07 0.12 0.12 0.12 (cc-mm / m ² -day-atm) * This is the number of pinholes per 100 cm ² of the area of the stretched film.

[0102]

Table 3 Comparative Example No. 1 2 3 4 5 Resin Used Polyamide used PA1 PA2 PA3 PA1 PA3 PET mixing amount (parts by weight) 0 0 0 2 2 Melt viscosity ratio---1.95 0.18 Number of pinholes (pieces) ^* 10.9 10.5 9.8 10.2 9.0 Haze value (%) 1.6 1.4 1.9 1.9 2.1 Oxygen permeability coefficient 0.05 0.05 0.05 0.05 0.05 (cc-mm / m ² -day-atm) * It is the number of pinholes per 100 cm ^{2 of the} stretched film area.

[0103]

[Table 4] Comparative Example No. 6 7 8 9 10 Resin Used Polyamide PA1 PA1 PA1 PA3 PA2 PET Mixing amount (parts by weight) 20 40 40 60 80 Melt viscosity ratio 4.17 4.17 8.96 0.08 0.79 Number of pinholes (pieces) ^* 4.7 3.9 5.5 - 2.7 haze (%) 19.2 17.7 25.6 - a ^{0.28 (cc-mm / m 2} -day-atm) * number of pinholes area 100 cm ² per stretched film - 4.9 oxygen permeability coefficient 0.07 0.08 0.09.

As is clear from Tables 1 and 2, the stretched film made of the mixed resin in which the crystalline polyamide of the present invention is mixed with the polyester is excellent in transparency and the pin of the stretched film made of the mixed resin. The number of holes was improved to less than half the number of pinholes of the stretched film of the crystalline polyamide alone shown in Comparative Example. Furthermore, a stretched film made of a mixed resin also has excellent gas barrier properties and is industrially very useful.

[0105]

The stretched film obtained by molding the mixed resin of the present invention has excellent pinhole resistance, gas barrier properties and transparency, and thus is useful as a material for films, sheets, containers and the like.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI B29K 77:00 B29L 7:00 (72) Inventor Katsuya Maruyama 5-6-1 Higashi-Hachiman, Hiratsuka-shi, Kanagawa Sanritsu Gas Chemical Co., Ltd. Hiratsuka Laboratory

Claims (5)

[Claims] 1. A crystalline polyamide (A) obtained from a diamine containing at least 70 mol% of meta-xylylenediamine and a dicarboxylic acid containing at least 70 mol% of adipic acid.
5% to 60% by weight of polyester (B) obtained from 40% by weight, a dicarboxylic acid containing 80% by mole or more of terephthalic acid, and a diol containing 80% by mole or more of ethylene glycol. ), A stretched polyamide film obtained by molding a mixed resin (C) with a crystalline polyamide (A) and a polyester (B).
The mixed resin (C) having a melt viscosity ratio at 75 ° C. ((melt viscosity of polyester (B) / melt viscosity of crystalline polyamide (A))) in the range of 0.1 to 3 is obtained by melt extrusion molding. A stretched polyamide film having excellent pinhole resistance, obtained by stretching the resulting sheet at least 2.0 times in the longitudinal and transverse directions, respectively. 2. A crystalline polyamide (A) obtained from a diamine containing not less than 70 mol% of meta-xylylenediamine and a dicarboxylic acid containing not less than 70 mol% of adipic acid.
5% to 60% by weight of polyester (B) obtained from 40% by weight, a dicarboxylic acid containing 80% by mole or more of terephthalic acid, and a diol containing 80% by mole or more of ethylene glycol. ), A stretched polyamide film obtained by molding a mixed resin (C) with a crystalline polyamide (A) and a polyester (B).
A sheet obtained by melt-extruding a mixed resin (C) having a melt viscosity ratio at 75 ° C. ((melt viscosity of polyester (B) / melt viscosity of crystalline polyamide (A))) in the range of 0.1 to 3 is used. , At least 2.0 each in the vertical and horizontal directions
Bending fatigue test 400 of a stretched film having a thickness of 10 to 40 μm stretched at least twice by gel gel tester
A stretched polyamide film having 7 pinholes / 100 cm ² or less after turning. 3. A crystalline polyamide (A) obtained from a diamine containing not less than 70 mol% of meta-xylylenediamine and a dicarboxylic acid containing not less than 70 mol% of adipic acid.
Polyester (B) obtained from 40% by weight, a dicarboxylic acid containing 80% by mole or more of terephthalic acid, and a diol containing 80% by mole or more of ethylene glycol (5% to 60% by weight (total of 100% by weight is 100% by weight) Is a stretched polyamide film obtained by molding a mixed resin (C) with
275 of crystalline polyamide (A) and polyester (B)
The ratio of the melt viscosity at (° C) [(melt viscosity of polyester (B) / melt viscosity of crystalline polyamide (A)]] is 0.1
A film obtained by melt-extruding the mixed resin (C) having a thickness of at least 2.0 times in each of the longitudinal and transverse directions, and having a thickness of the stretched film of 20 or more.
The haze value per μm is 15% or less, and the number PC of pinholes after 400 times of repeated bending fatigue tests of a stretched film made of the mixed resin (C) by a gel tester satisfies the formula (1). Stretched polyamide film with excellent pinhole resistance. PC ≦ 0.5 × PA (1) (PA is 400 times after repeated bending test of a stretched film of the same thickness obtained by molding using only the crystalline polyamide (A) instead of the mixed resin (C). Indicates the number of pinholes.) 4. The stretched polyamide film according to claim 1, wherein the crystalline polyamide (A) is polymethaxylylene adipamide. 5. The stretched polyamide film according to claim 1, wherein the polyester (B) is polyethylene terephthalate.