JP2000108203A - Manufacture of film and inflation molding die - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain two sheet-like films having good properties and appearances in a thermoplastic resin inflation film exhibiting an anisotropy at the time of melting. SOLUTION: In the case of generating two sheet-like films by using an inflation molding machine, first a pair of stable plates 54a, 54b are previously disposed so that their front edges Ha, Hb become substantially parallel to a line P for connecting centers of supports 6a, 6b. The air is blown into a molten resin extruded in a cylindrical state from an inflation molding die 50 to expand the resin, thereby generating a cylindrical film. The cylindrical film is flattened by the plates 54a, 54b, and taken off by a pinch roll. Both side edges of the cylindrical film are cut at a slit to generate two sheet-like films. These sheet- like films are continuously wound by a winder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a film for producing two sheet-like films by inflation film formation, and to an inflation molding die used in the production method. The present invention relates to a method for producing a film for producing two sheet-like films by inflation film formation of a thermoplastic resin to be presented, and an inflation molding die used in the production method.

[0002]

2. Description of the Related Art Thermoplastic resins exhibiting anisotropy when melted,
A typical example of a so-called liquid crystal polymer is a liquid crystal polyester. This liquid crystal polyester is generally called a melt-type liquid crystal (thermotropic liquid crystal) polymer. Unlike crystalline polymers such as polyethylene terephthalate and polybutylene terephthalate, the molecules are rigid, so they do not entangle even in the molten state. It has a behavior that the molecular chains are remarkably oriented in the flow direction by low shear force. Due to this unique behavior, the melt fluidity is extremely excellent, and a thin molded product of about 0.2 to 0.5 mm can be easily obtained, and this molded product has high strength and high rigidity. Have.

On the other hand, liquid crystal polyester is a polyester characterized in that molecules are oriented in a molten state by strong intermolecular interaction from the viewpoint of a film raw material. In addition to well-known properties such as high strength, high elastic modulus and high heat resistance, industrialization as a film material having functions such as gas barrier properties has been expected.

However, the liquid crystal polyester has a disadvantage that the anisotropy is extremely large. In addition, as described above, liquid crystal polyester does not entangle even in the molten state because the molecules are rigid, and the molecular chains are remarkably oriented in the flow direction. It shows a behavior that the tension is extremely low. Therefore, it is very difficult to maintain the shape in the molten state, and it is difficult to balance the vertical and horizontal performance due to the orientation of the molecules.In extreme cases, the film may tear in the direction of the molecular orientation. There was a major problem that the utility in fields such as molding was poor. Therefore, a liquid crystal polyester film utilizing the function of the liquid crystal polyester has not been sufficiently put to practical use.

For such a liquid crystal polyester, a method for producing a film by inflation film formation has been attempted. Inflation film formation means that resin melt-kneaded in an extruder is extruded into a cylindrical shape from an annular slit (resin flow path) of a cylindrical inflation molding die, and a certain amount of air is fed into the cylindrical resin. Then, the resin is expanded and continuously wound up while being cooled to form a cylindrical film or two sheets of film.

[0006] By such inflation film formation, 2
As a method for producing two sheet films, for example, JP-A-3-288623 and JP-A-4-49026
There is known a method for producing a liquid crystalline polymer film described in Japanese Unexamined Patent Publication (Kokai) No. H11-15095. The publications described in these publications extrude a liquid crystalline polymer melted by an extruder into a cylindrical shape from an annular slit of an inflation die, and supply a gas supply connected to an inflation die to a hollow portion of the cylindrical liquid crystalline polymer. Air or the like is supplied from a pipe to expand the tube, thereby forming a tubular film. The tubular film is guided by a guide plate and taken up by a nip roll. Then, both side edges of the tubular film folded by the nip roll are slit with slitters, and the resulting laminated films are wound up by rollers via a pair of rollers.

As an inflation molding die used for inflation film formation, for example, Japanese Patent Publication No.
No. 2,635,383, which includes an inner lip, an outer lip, an inner mandrel, a die body, and a vent hole for injecting air, and a spiral mandrel for equalizing the flow rate of the polymer material. Some have a polymer channel.

[0008]

SUMMARY OF THE INVENTION Liquid crystal polyesters are:
It has the property of being less viscous and easier to flow than polyethylene and polypropylene. For this reason, the above-mentioned
In the case of inflation film-forming a liquid crystal polyester using an inflation molding die described in US Pat. No. 2,635,383, a part of the resin does not flow between spiral projections (spiral grooves) formed on a spiral mandrel, It flows upward between the projection and the die body without passing through, and as a result, the effect of pressure distribution by the spiral groove is lost, and the resin flow becomes uneven in the circumferential direction. Therefore, using such a die, Japanese Patent Laid-Open No.
When the film production method described in JP-A-88623 and JP-A-4-49026 was carried out, the obtained 2
Weld lines and uneven thickness are generated in one sheet-like film, and a film having good properties and appearance cannot be produced.

On the other hand, in the conventional inflation film formation, in addition to a so-called spiral die for inflation molding provided with a spiral mandrel as described in the above-mentioned prior art, a so-called so-called die for supporting a mandrel on a die body with a plurality of supports. There is a method using a spider die. However, this spider die has a low rectifying property because a plurality of supports block the resin flow path, and the flow of the resin is considered to be non-uniform in the circumferential direction in the same manner as described above. It is not suitable for a liquid crystal polyester having, and has not been used conventionally.

An object of the present invention is to provide a method for producing a film capable of obtaining two sheet-like films having good properties and appearance in inflation film formation of a thermoplastic resin exhibiting anisotropy when melted, and a method for inflation molding. To provide a die.

[0011]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that when two sheet-like films are to be produced, the cylindrical film is flattened by a stabilizer (guide plate). Focusing on cutting both side edges of the cylindrical film, if weld lines and uneven thickness are present only on both sides of the cylindrical film, cut the portions to obtain weld lines and uneven thickness. It has been found that it is possible to produce a film without defects. Also,
In the case of inflation film formation using a spider die, if the installation positions of a plurality of supports are devised, weld lines and uneven thickness caused by the influence of the supports are present only on both side edges of the cylindrical film. I speculated that it would be possible.

Therefore, the present inventors have completed the present invention in order to achieve the above object. That is, the present invention extrudes a molten resin into a cylindrical shape from an inflation molding die, expands the resin by blowing gas into the cylindrical resin to form a cylindrical film, and with respect to the extrusion direction of the resin. The cylindrical film is flattened by a pair of stabilizers arranged so as to face each other so as to be tapered, and both side edges of the cylindrical film are cut to produce two sheet films. In the method of manufacturing a film to be wound, respectively, as a die for inflation molding, a die body having a hollow portion, a mandrel arranged in the hollow portion of the die body, and an annular shape formed by a gap between the die body and the mandrel. A plurality of supports arranged in the resin flow path and supporting the mandrel to the die body; and a cylindrical tree extruded from a resin outlet of the resin flow path. And a ventilation path for passing gas to inflate the die, wherein the plurality of supports are disposed in one of two sets of opposed included angles formed by two lines passing through the central axis of the mandrel. And a pair of stabilizers are arranged such that the leading edges of the pair of stabilizers are substantially parallel to a line connecting the centers of one of the two sets of opposed narrow angle regions. And flatten the cylindrical film.

In the present invention configured as described above,
A plurality of supports for the inflation molding die are disposed in one of two sets of opposing included areas formed by two lines passing through the central axis of the mandrel, and a pair of stabilizers are provided in two sets. By arranging the leading edge of the plate to be substantially parallel to a line connecting the centers of one of the opposed narrow angle regions, when the cylindrical film is flattened by the stabilizer, Weld lines and uneven thickness caused by the influence are present only on both side edges of the cylindrical film. Therefore, by cutting both side edges of the cylindrical film, weld lines, thickness unevenness, and the like are almost eliminated in the obtained two sheet-like films, and as a result, the appearance of the film is improved. Further, since the thickness unevenness of the film is reduced, the tensile strength in the lateral direction of the film is improved, and the properties of the film are also improved.

In the above method for producing a film, preferably, as the inflation molding die, at least one of the plurality of supports is formed by two lines passing through the central axis of the mandrel, one of the opposing 45-degree regions. And a pair of stabilizers are connected to each other by using a die in which another support is disposed on the other side in the opposed 45-degree area.
The pair of stabilizers are arranged such that the leading edge portions of the pair of stabilizers are substantially parallel to a line connecting the centers of the degree regions.

Accordingly, when the cylindrical film is flattened by the stabilizer, the area occupied by weld lines and uneven thickness generated on both side edges of the cylindrical film is reduced. Two large sheet-like films can be produced.

The present invention also relates to an inflation molding die used for inflation film formation of a thermoplastic resin exhibiting anisotropy when melted, wherein the die body has a hollow portion and the die body is disposed in the hollow portion of the die body. Mandrel, a plurality of supports arranged in an annular resin flow path formed by a gap between the die body and the mandrel, supporting the mandrel to the die body, and extruded from the resin outlet of the resin flow path. An air passage for allowing gas to expand the cylindrical resin, wherein at least one of the plurality of supports is formed by two lines passing through a central axis of the mandrel.
Place one in the 5 degree area and face the other support 4
It is configured to be arranged on the other side of the 5 degree region.

Thus, the above-described method for producing a film can be carried out, so that two sheet-like films having good properties and appearance and having almost no weld lines and uneven thickness can be produced. In addition, since a spiral die is not required, it is not necessary to form a spiral projection on the surface of the mandrel, thereby making it possible to easily manufacture an inflation molding die. Furthermore, the absence of helical protrusions simplifies the resin flow path, causing the thermoplastic resin exhibiting a large shear rate dependence of melt viscosity and exhibiting anisotropy during melting to accumulate and generate foreign matter that impairs the film appearance. The danger of doing so is reduced.

In the above-mentioned inflation molding die, preferably, the number of the supports is two, and one of the two supports is disposed in one of the opposed 45-degree regions, and the other of the two supports is provided. Is arranged on the other side within the 45-degree region opposed to each other. In this case, arranging the two supports facing each other on a line passing through the central axis of the mandrel,
Particularly preferred. Thereby, the structure of the inflation molding die is simplified, and the die can be manufactured more easily.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a longitudinal sectional view showing one embodiment of the inflation molding die according to the present invention, and FIG. 2 is a top view thereof. In the figure, an inflation molding die 50 includes a cylindrical die body 2 having a hollow portion,
A cylindrical movable ring 8 having a hollow portion is attached to the upper surface of the die body 2 so as to be dividable, and is disposed coaxially with the die body 2 and the movable ring 8 in the hollow portions of the die body 2 and the movable ring 8. Mandrel 4 and die body 2
The mandrel 4 is disposed in the gap between the
Are supported on the die body 2. The inner surfaces of the die body 2 and the movable ring 8 and the surface of the mandrel 4 are both smooth, and their average roughness (Ra) is preferably 5.0 or less.

The die main body 2 is composed of an outer mold lower part 22 and an outer mold upper part 24 which is splitably mounted on the upper part of the outer mold lower part 22 so that the die 50 can be easily assembled or disassembled. The outer mold lower part 22 has a mandrel insertion part 22a having a curved lower part, and a resin inlet part 10 provided at a lower part of the mandrel insertion part 22a for taking a molten resin described later into the die 50. are doing. The outer mold upper portion 24 has a tapered shape in which the inner diameter decreases from the lower portion to the upper portion.

The upper part of the outer mold lower part 22 and the outer mold upper part 24
The two support members 6a and 6b
There are formed two concave portions 26a and 26b for attaching the two. As shown in FIG. 2, the recesses 26a and 26b are formed by a line L passing through the center axis of the die main body 2 within an opposing 30-degree region formed by two lines passing through the center axis of the die main body 2.
It is arranged facing upward.

The mandrel 4 includes a core lower part 42 and a core upper part 44 which is divided and mounted on the upper part of the core lower part 42 so that the die 50 can be easily assembled or disassembled in the same manner as the die body 2. And a core land portion 46 which is dividably mounted on the upper portion of the core upper portion 44. The lower part of the core lower part 42 has a curved shape corresponding to the mandrel insertion part 22a of the outer die lower part 22.

On the upper side surface of the core lower part 42, two supports 6a and 6b are fixed integrally. As shown in FIG. 2, the supports 6a and 6b are opposed to each other by 30 degrees formed by two lines passing through the center axis of the mandrel 4, corresponding to the recesses 26a and 26b formed in the die body 2. Are arranged on a line L passing through the central axis of the mandrel 4 in the region of the above. In such dimensions, the supports 6a, 6b
Can reliably support the mandrel 4 on the die body 2 and can sufficiently withstand the force applied by the flow of resin described later.
The supports 6a and 6b are inserted into the recesses 26a and 26b, respectively, and are fixed to the die body 2 with bolts or the like.

As shown in FIG. 3, the supports 6a and 6b have a streamlined vertical cross section. Here, the streamline refers to a shape in which the flow of the surrounding fluid (here, molten resin) is smooth and the resistance of the fluid is small, and includes not only a curved shape but also a shape having a straight portion in part. .

The supports 6a and 6b are fixed integrally to the lower core portion 42. In addition, for example, concave portions are respectively opposed to the inner peripheral surface of the die body 2 and the outer peripheral surface of the mandrel 4. The support may be inserted into each of the recesses, and the support may be fixed to the die body 2 and the mandrel 4 with bolts or the like.

The core upper portion 44 has a tapered shape corresponding to the outer die upper portion 24 and having a diameter decreasing from the lower portion to the upper portion. The core land portion 46 has a substantially constant diameter in the vertical direction. The diameter of the movable ring 8 is also substantially constant in the vertical direction.

The resin inlet 10 provided in the outer mold lower part 22 of the die body 2, the gap between the die body 2 and the mandrel 4, and the gap between the movable ring 8 and the mandrel 4 are formed at the lower end in the die 50. A resin flow path 12 for flowing the molten resin from the portion to the upper end is formed.

The gap between the outer mold upper portion 24 of the die main body 2 and the core upper portion 44 of the mandrel 4 in such a resin flow path 12 has a structure that is rapidly tapered (tapered). The gap between the movable ring 8 and the core land portion 46 of the mandrel 4 is substantially constant.

Here, the gap of the resin flow path 12 at a predetermined position below the mandrel 4 is G1, and the supports 6a and 6b
G2 is the gap of the resin flow path 12 in the immediately adjacent portion of
The gap of the resin flow path 12 at the resin outlet 14 is G3
Then, the relationship of G1>G2> G3 is established.
That is, the horizontal cross-sectional area of the resin flow path 12 at the resin outlet portion 14 is smaller than the horizontal cross-sectional area of the resin flow path 12 at a portion immediately above the supports 6a and 6b. The pressure can rise. At this time, the resin pressure rises too much, and
b, the horizontal cross-sectional area of the resin flow channel 12 at the resin outlet portion 14 should be adjusted in the horizontal resin flow channel 1 at the portion immediately above the supports 6a and 6b.
Preferably, the cross-sectional area of 2 is 1/50 to 1 / 1.2, more preferably 1/25 to 1 / 1.5,
Most preferably, it is 1/15 to 1/2.

The inflation molding die 50
Is inserted into an air introduction pipe (vent path) 32 through which air for expanding the cylindrical resin extruded from the resin outlet portion 14 of the resin flow path 12 and through holes provided in the die body 2 and the movable ring 8. The die body 2 and the movable ring 8
And the outer peripheral surfaces of the die body 2 and the movable ring 8 are covered, and based on the temperature measured by the thermocouple 36, the resin flowing through the resin flow path 12 is kept in a molten state. In order to adjust and improve uneven thickness (thickness unevenness) of the produced film (described later) provided on the movable ring 8 and the heater band 34 for heating so as to be heated, Multiple adjusting bolts 38 for applying force
And

The air introduction pipe 32 extends through the outer mold lower part 22, the support 6b, and the core lower part 42 of the mandrel 4 toward the central axis of the mandrel 4, and the mandrel 4
Is bent upward at the central axis position of, and extends as it is to the upper end of the mandrel 4 to form an air outlet 32b. Also,
The air introduction pipe 32 is connected to the external air introduction pipe 32a, and air from the external air introduction pipe 32a is
And blown out from the air outlet 32b into the cylindrical resin extruded above the mandrel 4 to expand the resin.

Here, air is blown into the cylindrical resin, but instead of air, nitrogen,
Hydrogen, oxygen, argon, helium, or a mixed gas thereof may be introduced.

FIG. 4 is a structural view showing an inflation molding apparatus provided with the above-mentioned inflation molding die 50. As shown in FIG. The inflation molding device 70 includes, in addition to the inflation molding die 50, an extruder 52 having a temperature adjustment facility, a pair of stabilizers 54a and 54b, a pinch roll 56, a slitter 58, and winders 60a and 60b.
And guide rollers 62, 63 and 64.

The extruder 52 has a screw 52b rotated by a driving section 52a and a temperature control device (not shown). The screw 52b and the temperature control device heat the solid particulate resin stored in the hopper 52c. In a uniform molten state, inflation molding die 50
Send to

The pair of stabilizers 54a and 54b are disposed so as to be tapered (C-shape) with respect to the upper direction (the resin extrusion direction).
The cylindrical film J extruded from the air and expanded by air is flattened. The pinch roll 56 is a metal roll 56
a and a rubber roll 56b, and the cylindrical film flattened by the stabilizer 54 is continuously taken up. Slitter 5
8 cuts both side edges of the cylindrical film sent from the pinch roll 56 via the guide roller 62 to generate two sheet films. Winders 60a, 60b
Takes up two sheet-like films continuously fed through the guide rollers 63 and 64, respectively.

Here, the extruder 52 and the inflation molding die 50 are fixed on the floor,
4a, 54b, pinch roll 56, slitter 58, winders 60a, 60b, and guide rollers 62 to 64 are arranged on a rotary table (not shown). By rotating the rotary table, the positions of the stabilizers 54a and 54b with respect to the inflation molding die 50 can be changed.

Next, the resin used when inflation film formation is performed by the inflation molding apparatus 70 configured as described above will be described.

In the present embodiment, a thermoplastic resin exhibiting anisotropy when melted is used as the resin. Here, the thermoplastic resin exhibiting anisotropy when melted refers to a so-called melt-type liquid crystal (thermotropic liquid crystal) polymer, and the preferred thermoplastic resin is a liquid crystal polyester.

Specific examples of the liquid crystal polyester include: (1) a product obtained by reacting an aromatic dicarboxylic acid, an aromatic diol, and an aromatic hydroxycarboxylic acid; and (2) a reaction between different aromatic hydroxycarboxylic acids. (3) Products obtained by reacting an aromatic dicarboxylic acid with a nucleus-substituted aromatic diol (4) Products obtained by reacting an aromatic hydroxycarboxylic acid with a polyester such as polyethylene terephthalate And an anisotropic melt is preferably formed at a temperature of 400 ° C. or lower. In addition, aromatic dicarboxylic acid,
Instead of aromatic diols and hydroxycarboxylic acids, their ester derivatives may be used.

Examples of the repeating structural unit of the liquid crystal polyester include the following repeating structural units derived from an aromatic dicarboxylic acid, the following repeating structural units derived from an aromatic diol, and the following repeating structural units derived from an aromatic hydroxycarboxylic acid. However, the present invention is not limited to these. Repeating structural unit derived from aromatic dicarboxylic acid:

[0042]

Embedded image Repeating structural unit derived from aromatic diol:

[0043]

Embedded image

[0044]

Embedded image Repeating structural unit derived from aromatic hydroxycarboxylic acid:

[0045]

Embedded image Heat resistance, mechanical properties, particularly preferred liquid crystal polyester from the balance of workability,

[0046]

Embedded image And more preferably contains at least 30 mol% or more of such a repeating structural unit. Specifically, the combination of the repeating structural units is preferably any one of the following (I) to (VI).

[0047]

Embedded image

[0048]

Embedded image

[0049]

Embedded image The production methods of the above liquid crystal polyesters (I) to (VI) are described, for example, in JP-B-47-47870 and JP-B-63
Japanese Patent Publication No. -3888, Japanese Patent Publication No. 63-3891, Japanese Patent Publication No. 56-18016, Japanese Patent Laid-Open Publication No. 2-51523, and the like. Of these, a combination of (I), (II) or (IV) is preferable, and a combination of (I) or (II) is more preferable.

In this embodiment, in the field where high heat resistance is required, the liquid crystal polyester of the component (A) contains 30 to 80 mol% of the following repeating unit (a ′) and 0% of the repeating unit (b ′). -10 mol%, and the repeating unit (c ') is 10
２５25 mol%, repeating unit (d ′) is 10 to 35 mol%
Is preferably used.

[0051]

Embedded image (In the formula, Ar is a divalent aromatic group.) As the film of the present embodiment, in the field in which easy disposal such as incineration after use is required from the viewpoint of environmental problems, each of the above-mentioned fields is used. Among the preferred combinations in the field required for the above, a liquid crystal polyester by a combination consisting of elements of only carbon, hydrogen and oxygen is particularly preferably used.

As the thermoplastic resin exhibiting anisotropy when melted in the present embodiment, more preferably, (A) a copolymer having a liquid crystalline polyester as a continuous phase and (B) having a functional group reactive with the liquid crystalline polyester. Is a liquid crystal polyester resin composition having as a dispersed phase, whereby a film having flexibility and less uneven thickness can be obtained.

The component (B) used in such a liquid crystal polyester resin composition is a copolymer having a functional group reactive with the liquid crystal polyester. The functional group reactive with the liquid crystal polyester is not particularly limited as long as it has reactivity with the liquid crystal polyester, and specific examples include an oxazolyl group, an epoxy group, and an amino group.
Preferably, it is an epoxy group.

The epoxy group and the like may be present as a part of another functional group, such as a glycidyl group.

In the copolymer (B), the method for introducing such a functional group into the copolymer is not particularly limited, and it can be carried out by a known method. For example, at the stage of synthesizing the copolymer, it is possible to introduce the monomer having the functional group by copolymerization, or it is also possible to graft copolymerize the monomer having the functional group to the copolymer. It is.

As the monomer having a functional group reactive with the liquid crystal polyester, particularly, the monomer containing a glycidyl group, unsaturated carboxylic acid glycidyl ester and / or unsaturated glycidyl ether is preferably used.

The unsaturated carboxylic acid glycidyl ester is
Preferably a general formula

[0058]

Embedded image (R is a hydrocarbon group having an ethylenically unsaturated bond and having 2 to 13 carbon atoms.)

The unsaturated glycidyl ether preferably has the general formula

[0060]

Embedded image (R is a hydrocarbon group having 2 to 18 carbon atoms which has an ethylenically unsaturated bond, X is -CH ₂ -O- or

[0061]

Embedded image It is. ).

Specifically, examples of unsaturated glycidyl carboxylate include glycidyl acrylate, glycidyl methacrylate, diglycidyl itaconate, triglycidyl butenetricarboxylate,
Glycidyl p-styrenecarboxylate and the like can be mentioned.

Examples of the unsaturated glycidyl ether include vinyl glycidyl ether, allyl glycidyl ether, 2-methylallyl glycidyl ether, methacryl glycidyl ether, and styrene-p-glycidyl ether.

The copolymer (B) having a functional group reactive with the liquid crystal polyester preferably contains 0.1 to 30% by weight of an unsaturated carboxylic acid glycidyl ester unit and / or an unsaturated glycidyl ether unit. It is a copolymer containing.

The copolymer (B) having a functional group reactive with the liquid crystal polyester may be a thermoplastic resin or a rubber, or a mixture of a thermoplastic resin and a rubber. You may. Rubber is preferable because it has better thermal stability and flexibility.

More preferably, the copolymer (B) having a functional group reactive with the liquid crystal polyester is
A copolymer having a heat of fusion of crystal of less than 3 J / g.

The copolymer (B) preferably has a Mooney viscosity of from 3 to 70, more preferably from 3 to 30, and particularly preferably from 4 to 25.

The Mooney viscosity referred to here is JIS K6
A value measured using a large rotor at 100 ° C. according to 300.

The rubber as used herein refers to a polymer substance having rubber elasticity at room temperature according to a new edition of Polymer Dictionary (edited by the Society of Polymer Science, published in 1988, Asakura Shoten). Examples thereof include natural rubber, butadiene polymer, butadiene-styrene copolymer (including random copolymer, block copolymer (including SEBS rubber or SBS rubber, etc.), and graft copolymer), or hydrogenation thereof. Product, isoprene polymer, chlorobutadiene polymer, butadiene-acrylonitrile copolymer, isobutylene polymer, isobutylene-butadiene copolymer rubber, isobutylene-isoprene copolymer, acrylate-ethylene copolymer rubber, ethylene- Propylene copolymer rubber, ethylene-butene copolymer rubber, ethylene-propylene Styrene copolymer rubber, styrene-isoprene copolymer rubber, styrene-butylene copolymer, styrene-ethylene-propylene copolymer rubber, perfluoro rubber, fluorine rubber, chloroprene rubber, butyl rubber, silicone rubber, ethylene-propylene- Non-conjugated diene copolymer rubber, thiol rubber, polysulfide rubber, polyurethane rubber, polyether rubber (for example, polypropylene oxide), epichlorohydrin rubber, polyester elastomer, polyamide elastomer and the like. Among them, acrylate-ethylene copolymers are preferably used, and (meth) acrylate-
Ethylene copolymer rubber is more preferred.

These rubber-like substances can be produced by any production method (eg, emulsion polymerization method, solution polymerization method, etc.) and any catalyst (eg, peroxide, trialkylaluminum, lithium halide, nickel-based catalyst, etc.). It may be something.

In the present embodiment, the rubber as the copolymer (B) is a rubber having a functional group reactive with the liquid crystal polyester in the above rubber.

In such a rubber, a method for introducing a functional group reactive with the liquid crystal polyester into the rubber is not particularly limited, and it can be carried out by a known method. For example, at the stage of rubber synthesis, it is also possible to introduce a monomer having the functional group by copolymerization,
It is also possible to graft copolymerize a monomer having the functional group to rubber.

As specific examples of the copolymer (B) having a functional group reactive with the liquid crystal polyester, rubbers having an epoxy group include (meth) acrylate-ethylene- (unsaturated glycidyl carboxylate and And / or unsaturated glycidyl ether) copolymer rubber.

Here, the (meth) acrylic acid ester is
An ester obtained from acrylic acid or methacrylic acid and an alcohol. Alcohols have 1 carbon atom
~ 8 alcohols are preferred. Specific examples of (meth) acrylates include methyl acrylate, methyl methacrylate, n-butyl acrylate, n-butyl methacrylate, tert-butyl acrylate, ter
Examples thereof include t-butyl methacrylate, 2-ethylhexyl acrylate, and 2-ethylhexyl methacrylate. As the (meth) acrylic acid ester, one kind thereof may be used alone, or two or more kinds may be used in combination.

Preferably, the content of the (meth) acrylate unit is more than 40% by weight and less than 97% by weight, more preferably 45 to 70% by weight, and the ethylene unit is 3% by weight to 5% by weight.
0% by weight, more preferably 10 to 49% by weight, 0.1 to 30% by weight of unsaturated carboxylic acid glycidyl ether unit and / or unsaturated glycidyl ether unit,
More preferably, it is 0.5 to 20% by weight.

If the ratio is outside the above range, the thermal stability and mechanical properties of a molded product such as a film or a sheet obtained from the composition may be insufficient, which is not preferable.

The copolymer rubber can be produced by a usual method, for example, bulk polymerization, emulsion polymerization, solution polymerization or the like using a free radical initiator. Typical polymerization methods are described in JP-B-46-45085 and JP-B-6-45085.
No. 1-127709, pressure of 500 k in the presence of a polymerization initiator generating free radicals
g / cm ² or more and a temperature of 40 to 300 ° C.

Other examples of the rubber that can be used in the copolymer (B) of the present embodiment include an acrylic rubber having a functional group reactive with the liquid crystal polyester and a vinyl aromatic having a functional group reactive with the liquid crystal polyester. A group hydrocarbon compound-conjugated diene compound block copolymer rubber can also be exemplified.

The acrylic rubber mentioned here is preferably represented by the general formula (1)

[0080]

Embedded image (Wherein, R 1 represents an alkyl group having 1 to 18 carbon atoms or a cyanoalkyl group), and general formula (2)

[0081]

Embedded image (Wherein R2 is an alkylene group having 1 to 12 carbon atoms,
3 represents an alkyl group having 1 to 12 carbon atoms. ) And general formula (3)

[0082]

Embedded image (Wherein, R4 is a hydrogen atom or a methyl group, R5 is an alkylene group having 3 to 30 carbon atoms, and R6 is a 1 to 20 carbon atom.
Wherein n represents an integer of 1 to 20; )) At least one monomer selected from the compounds represented by the formula (1).

Specific examples of the alkyl acrylate represented by the general formula (1) include, for example, methyl acrylate, ethyl acrylate, propyl acrylate,
Examples thereof include butyl acrylate, pentyl acrylate, hexyl acrylate, actyl acrylate, 2-ethylhexyl acrylate, nonyl acrylate, decyl acrylate, dodecyl acrylate, and cyanoethyl acrylate.

The alkoxyalkyl acrylate represented by the general formula (2) includes, for example, methoxyethyl acrylate, ethoxyethyl acrylate, butoxyethyl acrylate, ethoxypropyl acrylate and the like. One or more of these can be used as the main component of the acrylic rubber.

As a constituent component of the acrylic rubber, an unsaturated monomer copolymerizable with at least one monomer selected from the compounds represented by the above general formulas (1) to (3), if necessary. Can be used.

Examples of such unsaturated monomers include styrene, α-methylstyrene, acrylonitrile, halogenated styrene, methacrylonitrile, acrylamide, methacrylamide, vinylnaphthalene, N-methylolacrylamide, vinyl acetate, vinyl chloride, Examples include vinyl, vinylidene chloride, benzyl acrylate, methacrylic acid, itaconic acid, fumaric acid, and maleic acid.

The preferred constituent ratio of the acrylic rubber having a functional group reactive with the liquid crystal polyester is at least one monomer selected from the compounds represented by the above general formulas (1) to (3). 0 to 99.9% by weight, 0.1 to 30.0% by weight of unsaturated carboxylic acid glycidyl ester and / or unsaturated glycidyl ether, selected from the compounds represented by the above general formulas (1) to (3). Unsaturated monomer copolymerizable with at least one monomer 0.0
３30.0% by weight.

When the constituent ratio of the acrylic rubber is within the above range, the heat resistance, impact resistance and molding processability of a molded article such as a film or a sheet obtained from the composition are favorable, which is preferable.

The method for producing the above-mentioned acrylic rubber is not particularly limited. For example, JP-A-59-113010, JP-A-62-64809, and JP-A-3-160.
008, or a known polymerization method as described in WO95 / 04764 or the like can be used.
It can be produced by emulsion polymerization, suspension polymerization, solution polymerization or bulk polymerization in the presence of a radical initiator.

The vinyl aromatic hydrocarbon compound-conjugated diene compound block copolymer rubber having a functional group reactive with the liquid crystal polyester is preferably (a)
Epoxidation of a rubber obtained by epoxidizing a block copolymer consisting of a sequence mainly composed of a vinyl aromatic hydrocarbon compound and (b) a sequence mainly composed of a conjugated diene compound, or epoxidation of a hydrogenated product of the block copolymer This is the rubber obtained.

The vinyl aromatic hydrocarbon compound-conjugated diene compound block copolymer or its hydrogenated product can be produced by a well-known method.
798 and JP-A-59-133203.

As the aromatic hydrocarbon compound, for example,
Styrene, vinyltoluene, divinylbenzene, α-methylstyrene, p-methylstyrene, vinylnaphthalene and the like can be mentioned, among which styrene is preferable.

As the conjugated diene compound, for example, butadiene, isoprene, pyrrylene, 1,3-pentadiene, 3-butyl-1,3-octadiene and the like can be mentioned, butadiene or isoprene is preferred.

The rubber used as the copolymer (B) is preferably (meth) acrylate-ethylene-
(Unsaturated carboxylic acid glycidyl ester and / or unsaturated glycidyl ether) copolymer rubber is used.

The rubber used as the copolymer (B) may be vulcanized as required and used as a vulcanized rubber.

The above-mentioned (meth) acrylic acid ester-ethylene- (unsaturated carboxylic acid glycidyl ester and / or
Alternatively, the vulcanization of the unsaturated glycidyl ether) copolymer rubber can be achieved by using a polyfunctional organic acid, a polyfunctional amine compound, an imidazole compound, or the like, but is not limited thereto.

Further, as a specific example of the copolymer (B) having a functional group reactive with the liquid crystal polyester, a thermoplastic resin having an epoxy group includes (a) 50 to 99% by weight of ethylene units, (b) ) 0.1 to 30% by weight, preferably 0.5 to 20% by weight of unsaturated carboxylic acid glycidyl ester units and / or unsaturated glycidyl ether units.
% By weight, and (c) an epoxy group-containing ethylene copolymer having an ethylenically unsaturated ester compound unit of 0 to 50% by weight.

Examples of the ethylenically unsaturated ester compound (c) include vinyl carboxylate such as vinyl acetate, vinyl propionate, methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate and butyl methacrylate. Esters, α, β-unsaturated carboxylic acid alkyl esters, and the like. Particularly, vinyl acetate, methyl acrylate and ethyl acrylate are preferred.

Specific examples of the epoxy group-containing ethylene copolymer include, for example, a copolymer composed of ethylene units and glycidyl methacrylate units, a copolymer composed of ethylene units and glycidyl methacrylate units and a methyl acrylate unit, and a copolymer composed of ethylene units and glycidyl methacrylate units. A copolymer consisting of methacrylate units and ethyl acrylate units,
Copolymers composed of an ethylene unit, a glycidyl methacrylate unit and a vinyl acetate unit are exemplified.

The melt index (hereinafter sometimes referred to as MFR) of an epoxy group-containing ethylene copolymer.
K6760, 190 ° C., 2.16 kg load) is preferably 0.5 to 100 g / 10 min, more preferably 2 to 100 g / 10 min.
50 g / 10 min. The melt index may be outside this range, but the melt index is 100 g /
If it exceeds 10 minutes, it is not preferable from the viewpoint of mechanical properties of the composition, and if it is less than 0.5 g / 10 minutes, the compatibility with the liquid crystal polyester of the component (A) may be inferior.

[0102] The epoxy group-containing ethylene copolymer is preferably in the range stiffness modulus of 10~1300kg / cm ^2, further preferably from 20~1100kg / cm ^2.

If the flexural rigidity is out of this range, the molding processability and mechanical properties of the composition may be insufficient, which is not preferable.

The epoxy group-containing ethylene copolymer is usually prepared by reacting an unsaturated epoxy compound and ethylene in the presence of a radical generator at 500 to 4000 atm and 100 to 300 ° C. in the presence or absence of a suitable solvent or chain transfer agent. It is produced by a high-pressure radical polymerization method in which copolymerization is performed below. It can also be produced by a method in which an unsaturated epoxy compound and a radical generator are mixed with polyethylene and melt-grafted and copolymerized in an extruder.

The liquid crystal polyester resin composition is a resin composition having (A) a liquid crystal polyester as a continuous phase and (B) a copolymer having a functional group reactive with the liquid crystal polyester as a dispersed phase. Is not a continuous phase, the gas barrier properties and heat resistance of a film made of the liquid crystal polyester resin composition may be significantly reduced, which is not preferred.

The details of the mechanism of such a resin composition of a copolymer having a functional group and a liquid crystal polyester are not clear, but the composition between the component (A) and the component (B) of the composition is not clear. It is considered that a reaction occurs, and the component (A) forms a continuous phase, and the component (B) is finely dispersed, thereby improving the moldability of the composition.

One embodiment of the liquid crystal polyester resin composition comprises (A) 56.0 to 99.9% by weight of liquid crystal polyester, preferably 65.0 to 99.9% by weight, more preferably 70 to 98% by weight, And (B) a copolymer having a functional group reactive with the liquid crystal polyester, 44.0 to 44.0.
The resin composition contains 0.1% by weight, preferably 35.0 to 0.1% by weight, and more preferably 30 to 2% by weight.

When the amount of the component (A) is less than 56.0% by weight, the gas barrier properties and heat resistance of a molded article such as a film or sheet obtained from the above composition may be reduced.
Not preferred. When the amount of the component (A) exceeds 99.9% by weight, the moldability of the composition may decrease,
In addition, the price is expensive, which is not preferable.

As a method for producing the liquid crystal polyester resin composition in the present embodiment, a known method can be used. For example, there is a method in which each component is mixed in a solution state and the solvent is evaporated or precipitated in the solvent. From an industrial point of view, a method of kneading each component of the above composition in a molten state is preferred. For the melt kneading, kneading devices such as a single-screw or twin-screw extruder and various kneaders which are generally used can be used. In particular, a biaxial high kneader is preferred.

In the melt kneading, the cylinder set temperature of the kneading apparatus is preferably in the range of 200 to 360 ° C., and more preferably 230 to 350 ° C.

At the time of kneading, the respective components may be previously mixed uniformly using a device such as a tumbler or a Henschel mixer, or if necessary, the mixing may be omitted, and each component may be separately supplied to the kneading device. Methods can also be used.

In the liquid crystal polyester resin composition used in the present embodiment, an inorganic filler is used if desired. Such inorganic fillers include calcium carbonate,
Talc, clay, silica, magnesium carbonate, barium sulfate, titanium oxide, alumina, gypsum, glass flake,
Glass fiber, carbon fiber, alumina fiber, silica-alumina fiber, aluminum borate whisker, potassium titanate fiber and the like are exemplified.

The liquid crystal polyester resin composition used in the present embodiment may further contain, if necessary, an organic filler, an antioxidant, a heat stabilizer, a light stabilizer, a flame retardant, a lubricant, an antistatic agent, and rust prevention. Various additives such as an agent, a cross-linking agent, a foaming agent, a fluorescent agent, a surface smoothing agent, a surface gloss improving agent, and a mold release improving agent such as a fluororesin can be used in the manufacturing process or in the subsequent processing.

Next, a method for inflating a thermoplastic resin exhibiting anisotropy at the time of melting to form two sheet films using the inflation molding apparatus 70 shown in FIG. 4 will be described.

First, by rotating a rotary table (not shown), as shown in FIG. 5, with respect to a line P connecting the centers of the supports 6a and 6b, the tip edges Ha and Hb of the stabilizing plates 54a and 54b. Are arranged in advance so as to be substantially parallel.

In this state, the driving unit 5 of the extruder 52
2a is controlled to rotate the screw 52b, and the solid particulate resin stored in the hopper 52c is melted and sent to the inflation molding die 50.

The melt-kneaded resin is taken in from the resin inlet 10 of the die 50, and flows through the annular resin flow path 12 through the die 50.
It flows upward and is extruded cylindrically from the resin outlet 14. At this time, the molten resin flowing through the portion passing through the supports 6a and 6b once branches due to the presence of the supports 6a and 6b as shown in FIG.
Is dimensioned such that it is located within an opposing 30-degree region formed by two lines passing through the central axis of the mandrel 4,
Since the ratio of the supports 6a and 6b occupying the resin flow path 12 is relatively small, the influence of the branching of the resin is small. Also,
Since the vertical cross-sectional shapes of the supports 6a and 6b are streamlined, the resistance applied to the resin is small and the resin flows relatively smoothly. Furthermore, the outer mold upper part 24 of the die body 2
The gap between the upper core portion 44 of the mandrel 4 and the mandrel 4 is tapered, which is combined with the fact that the inner diameter of the outer mold upper portion 24 of the die body 2 decreases from the lower portion to the upper portion, and the molten resin When flows above the supports 6a and 6b, the resin pressure rises, so that the flow of the molten resin stagnates. Therefore, the supports 6a, 6
The resin branched at the point b rapidly merges above the supports 6a and 6b. Further, when the molten resin passes through the gap between the movable ring 8 and the core land portion 46, a rectifying action is generated in the molten resin. Therefore, in a state where the flow of the molten resin is uniform to some extent in the circumferential direction, the resin outlet 14
, A cylindrical resin is extruded, and a certain amount of air is blown into the cylindrical resin to expand the cylindrical resin, thereby forming a cylindrical film. As a result, weld lines, thickness unevenness, and the like generated in the cylindrical film due to the influence of the supports 6a and 6b are reduced.

Then, the cylindrical film J is connected to the stabilizer 5
The sheet is flattened at 4a and 54b and taken up by a pinch roll 56. At this time, as described above, the stabilizers 54a, 54b
Are substantially parallel to the line P connecting the centers of the supports 6a, 6b, and therefore, the slight edges generated in the cylindrical film due to the influence of the supports 6a, 6b. Weld lines, uneven thickness, and the like are present only on both side edges of the cylindrical film.

The flattened cylindrical film is sent to a slit 58 via a guide roller 62, and the slit 58 cuts both side edges of the cylindrical film. As a result, two sheet-like films having almost no weld lines and uneven thickness are generated. afterwards,
The two sheet films are sent to winders 60a and 60b via guide rollers 63 and 64, respectively, and are continuously wound by the winders 60a and 60b.

Here, assuming that the diameter of the resin expanded by air is D, the blow ratio BR of the film (= D / R
2) is preferably set to 1.2 to 6.0. The film winding speed by the pinch roll 56 is 1 m
/ Min to 100 m / min. Further, the thickness of the film can be controlled by appropriately adjusting the blow ratio and the film take-up speed.
The thickness is preferably set to 00 μm, more preferably 3 to 500 μm.

As described above, according to the present embodiment, the supports 6a and 6b are arranged so as to face each other on a line passing through the central axis of the mandrel 4, and the stabilizers 54a and 54b are connected to the front edges Ha and Hb. Since the support members 6a and 6b are arranged so as to be substantially parallel to a line connecting the centers of the support members 6a and 6b, when the cylindrical films are flattened by the stabilizers 54a and 54b, the cylindrical members are formed under the influence of the support members 6a and 6b. Slight weld lines and uneven thickness occurring in the film are present only on both side edges of the cylindrical film. Therefore, by cutting both side edges of the cylindrical film with the slits 58, it is possible to obtain two sheet-like films having a good appearance and almost no weld lines and uneven thickness. In addition, since the thickness unevenness is reduced as described above, the tensile strength in the lateral direction of the sheet-like film is increased, and as a result, the properties of the film are improved.

At this time, since the ratio of the supports 6a and 6b in the resin flow path 12 is relatively small, the stabilizers 54a and 6b
When the cylindrical film is flattened at 54b, the area occupied by weld lines and uneven thickness generated on both side edges of the cylindrical film is reduced, thereby generating two sheet films having a relatively large width. be able to.

Further, in this embodiment, since the spiral die is not required, it is not necessary to form a spiral projection on the surface of the mandrel, and the number of the supports is two. Only two grooves need to be formed in the die body 2 for mounting. This simplifies the structure of the inflation molding die 50, and
Can be easily manufactured, and the cost of the die 50 itself can be greatly reduced. Furthermore, the absence of the spiral projections simplifies the resin flow path 12, and the shear rate dependence of the melt viscosity is large.
The risk of generating foreign matter that impairs the film appearance is reduced.

Further, since the thermoplastic resin exhibiting anisotropy at the time of melting easily flows easily, it is possible to flow the resin into the resin flow path 12 at a low pressure. For this reason, even if the ratio of the supports 6a and 6b occupying in the resin flow path 12 is relatively small as described above, the mandrel 4 is reliably supported on the die main body 2 and the force applied by the flow of the resin is sufficient. Can withstand. Incidentally, when a resin such as polyethylene or polypropylene is to be formed into an inflation film by using the inflation molding die 50 as described above, polyethylene or polypropylene or the like is more viscous than liquid crystal polyester. High pressure must be flowed into the passage 12, in which case the two supports 6a, 6
It is impossible to support the mandrel 4 on the die body 2 in b.

In the present embodiment, the mandrel 4 is supported on the die body 2 by the two supports 6a and 6b, and the dimensions of the supports 6a and 6b are changed.
The dimensions are such that they are arranged in an opposing 30-degree region formed by two lines passing through the central axis of the mandrel. However, the number and dimensions of the supports are not particularly limited thereto. What is necessary is just to arrange | position in one of two sets of opposing narrow-angle area | regions formed of two lines which pass through the central axis of four. In this case, the stabilizing plates 54a, 54b are arranged such that the leading edges Ha, Hb of the stabilizing plates 54a, 54b are substantially parallel to a line connecting the centers of one of the two sets of opposed narrow angles. To be placed.

At this time, when the cylindrical film is flattened by the stabilizers 54a and 54b, a plurality of supports are required to reduce the area occupied by weld lines and uneven thickness generated on both side edges of the cylindrical film. Are formed by two lines passing through the central axis of the mandrel 4
Place one in the 5 degree area and face the other support 4
It is preferable to place it on the other side of the 5 degree region.

The resin flow path 1 at the resin outlet 14
2, the horizontal cross-sectional area is smaller than the horizontal cross-sectional area of the resin flow path 12 in the portion immediately above the supports 6a and 6b, but these horizontal cross-sectional areas may be the same.

Further, the inner diameter of the outer mold upper portion 24 of the die body 2 is reduced from the lower portion to the upper portion.
3 is a resin flow path 1 in a portion immediately above the supports 6a and 6b.
If the gap G2 is sufficiently smaller than the gap G2, the gap G2 may be increased from the lower portion to the upper portion, or may be constant in the vertical direction.

The inner diameter of the movable ring 8 and the outer diameter of the core land portion 46 of the mandrel 4 are both substantially constant in the vertical direction, but these may be changed in the vertical direction as necessary. You may. In some cases, the movable ring 8 and the core land portion 46 may not be provided.

Furthermore, although the vertical cross-sectional shape of the support is a streamline, the vertical cross-sectional shape of the support is not limited to this, and may be a circle or an ellipse.

Further, the extruder 52 and the inflation molding die 50 are fixed on the floor, and the stabilizers 54a, 54a
b, pinch roll 56, slitter 58, winder 60a,
60b, the guide rollers 62 to 64 are arranged on a rotary table (not shown).
b, pinch roll 56, slitter 58, winder 60a,
The extruder 52 and the inflation molding die 50 may be rotatable by fixing the guide rollers 60b and the guide rollers 62 to 64.

Although the above-described inflation molding die 50 takes in the molten resin from the lower end and extrudes it upward from the upper end in a cylindrical shape, the present invention is not particularly limited to this, and the molten resin is fed from the upper end. The present invention can also be applied to an inflation molding die which takes in and extrudes a cylindrical shape downward from the lower end.

[0132]

According to the present invention, when two sheet-like films are formed by inflation film formation of a thermoplastic resin exhibiting anisotropy at the time of melting, both sides of a cylindrical film flattened by a stabilizer are formed. By concentrating the weld line and uneven thickness on the edge portion and cutting the same, it is possible to obtain a film having good properties and appearance with almost no weld line and uneven thickness.

Further, since it is not necessary to use a spiral die having spiral projections formed on the surface of the mandrel, it is possible to easily manufacture an inflation molding die, and to greatly reduce the cost of the die itself. Become.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of an inflation molding die according to the present invention.

FIG. 2 is a top view of the inflation molding die shown in FIG.

FIG. 3 is a diagram showing a cross-sectional shape of a support shown in FIG. 1 and a flow of resin.

4 is a configuration diagram of an inflation molding apparatus including the inflation molding die shown in FIG.

FIG. 5 is a diagram showing a positional relationship between two supports of the inflation molding die shown in FIG. 4 and a pair of stabilizers.

[Explanation of symbols]

2 ... die body, 4 ... mandrel, 6a, 6b ... support,
10: resin inlet, 12: resin flow path, 14: resin outlet, 10: air inlet tube, 50: inflation molding die, 54a, 54b: stabilizer.

Continued on front page F term (reference) 4F207 AA04 AA24 AC07 AE01 AG01 AR07 KA01 KF01 KL62 KL86 KM16 4F210 AA04 AA24 AC07 AE01 AG01 AR07 QA01 QG01 QG18 QK01 QK12 QK53

Claims (5)

[Claims] 1. A molten resin is extruded into a cylindrical shape from an inflation molding die, and a gas is blown into the cylindrical resin to expand the resin to form a cylindrical film. The cylindrical film is flattened by a pair of stabilizers arranged to face each other so as to be tapered, and both side edges of the cylindrical film are cut to produce two sheet films. In the method of manufacturing a film to wind each, as the inflation molding die, a die body having a hollow portion, a mandrel disposed in the hollow portion of the die body, and a gap between the die body and the mandrel. A plurality of supports arranged in the formed annular resin flow path and supporting the mandrel on the die body; and a resin outlet of the resin flow path. And a ventilation path for allowing gas to expand the cylindrical resin extruded from the part, and wherein the plurality of supports are formed by two lines passing through the central axis of the mandrel. Using a die arranged on one side of the included angle region, the pair of stabilizers is connected to a line connecting the centers of one of the two pairs of opposed included regions with each other. A method for manufacturing a film, wherein the cylindrical film is flattened by arranging the leading edge portions to be substantially parallel. 2. As the inflation molding die, at least one of the plurality of supports is disposed on one of opposing 45-degree regions formed by two lines passing through a central axis of the mandrel, and Using a die in which the supporting body is disposed on the other side in the opposed 45-degree area, and connecting the pair of stabilizers to a line connecting the centers of the opposed 45-degree areas. 2. The method for producing a film according to claim 1, wherein the edge of the stabilizer is arranged to be substantially parallel. 3. An inflation molding die used for inflation-forming a thermoplastic resin exhibiting anisotropy when melted, comprising: a die body having a hollow portion; and a mandrel disposed in the hollow portion of the die body. A plurality of supports arranged in an annular resin flow path formed by a gap between the die body and the mandrel and supporting the mandrel on the die body; and extruded from a resin outlet of the resin flow path. An air passage for passing a gas for expanding the cylindrical resin, wherein at least one of the plurality of supports is formed by two lines passing through a central axis of the mandrel. A die for inflation molding, wherein the die is disposed on one side of the region and the other support is disposed on the other side of the opposed 45 degree region. 4. The number of the supports is two, one of the two supports is arranged in one of the opposed 45-degree regions, and the other of the two supports is placed in the opposite 45 °. 4. The inflation molding die according to claim 3, wherein the die is arranged on the other side in the area of the degree. 5. The inflation molding die according to claim 4, wherein the two supports are arranged on a line passing through a central axis of the mandrel.