JPH11147963A - Easily tearable film, easily tearable packaging film comprising the sane, and easily tearable packaging bag and easily tearable lid prepared by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare a film which is excellent in moldability, heat resistance, gas barrier properties, and flex resistance and has good tearability. SOLUTION: This film is prepd. from a liq. crystalline polyester resin compsn. comprising a continuous phase of a liq. crystalline polyester and a disperse phase of a copolymer having functional groups reactive with the liq. crystalline polyester and has a ratio of the max. value to the min. value of the strength of transmitted microwave (measured when a microwave is radiated vertically to the film surface by the microwave method) of 1.2 or higher. The easily tearable packaging film comprises the film, and both the easily tearable packaging bag and the easily tearable lid are prepd. by using the film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an easily tearable film suitable for a tear-resistant packaging film.

[0002]

2. Description of the Related Art Packaging materials using plastic films are used in various fields of the industry such as bags, pouches for foods, beverages, pharmaceuticals, detergents, etc., but they do not always satisfy the demands of the market. The current situation is not satisfied. For example, olefin resins such as polyethylene and polypropylene have low heat resistance and poor gas barrier performance. Ethylene-vinyl acetate copolymers and the like have poor gas barrier properties especially under high humidity and insufficient heat resistance. Polyvinyl chloride or polyvinylidene chloride has low heat resistance and has a problem of combustion gas at the time of disposal.

[0003] Liquid crystal polyester is a polyester characterized in that molecules are oriented in a molten state by strong intermolecular interaction. Film formation is difficult due to the strong intermolecular interaction and molecular orientation. Strength,
High elastic modulus, high heat resistance, excellent films such as gas barrier properties are expected, but when used as a packaging material, these films are heat-sealed to obtain bags, pouches,
There is also a problem that it is not easy to open various packaging materials such as a lid. That is, the packaging material film is extremely difficult to tear by hand without a notch, even if a notch is inserted, it is still difficult to tear,
Problems have been pointed out, such as difficulty in opening a bag or the like because the crack does not run in a straight line even if it is torn. This problem has been strongly demanded especially by the market for infants and the elderly.

[0004]

SUMMARY OF THE INVENTION In view of the above circumstances, the problem to be solved by the present invention is to provide a film which is excellent in moldability, heat resistance, gas barrier properties, etc., excellent in bending resistance, and excellent in tearability. To provide.

[0005]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have reached the present invention. That is, the present invention uses a liquid crystal polyester 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, and using a microwave method. An easily tearable film, in which the ratio of the maximum value and the minimum value of the transmitted microwave intensity measured when irradiating the microwave perpendicular to the film surface is larger than 1.2, an easily tearable packaging film comprising the same, The present invention relates to an easily tearable packaging bag and an easily tearable lid.

[0006]

Next, the present invention will be described in more detail. The liquid crystal polyester of the component (A) of the liquid crystal polyester resin composition in the present invention is a polyester called a thermotropic liquid crystal polymer.

[0007] Specifically, (1) those comprising a combination of an aromatic dicarboxylic acid, an aromatic diol and an aromatic hydroxycarboxylic acid. (2) Those comprising a combination of different aromatic hydroxycarboxylic acids. (3) Those comprising a combination of an aromatic dicarboxylic acid and a nucleus-substituted aromatic diol. (4) Those obtained by reacting an aromatic hydroxycarboxylic acid with a polyester such as polyethylene terephthalate. And the like, which forms an anisotropic melt at a temperature of 400 ° C. or lower. In addition, in place of these aromatic dicarboxylic acids, aromatic diols, and aromatic hydroxycarboxylic acids, ester-forming derivatives thereof may be used.

The repeating structural units 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,
Examples of the repeating structural unit derived from an aromatic hydroxycarboxylic acid include, but are not limited to, these.

A repeating structural unit derived from an aromatic dicarboxylic acid:

[0010]

A repeating structural unit derived from an aromatic diol:

[0012]

A repeating structural unit derived from an aromatic hydroxycarboxylic acid:

A liquid crystal polyester which is particularly preferable from the balance of heat resistance, mechanical properties and workability is And more preferably at least 30 mol% or more of such a repeating structural unit. Specifically, the combination of repeating structural units is preferably any one of the following (I) to (VI).

[0015]

[0016]

[0017]

[0018]

[0019]

[0020]

The method for producing the liquid crystal polyesters (I) to (VI) is described, for example, in JP-B-47-47870, JP-B-63-3888, JP-B-63-3891, and JP-B-56-18016. JP-A-2-515
No. 23, 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 the field where high heat resistance is required in the present invention, the liquid crystal polyester of the component (A) contains 30 to 80 mol% of the following repeating unit (a ') and 0 to 100% of the repeating unit (b'). 10 mol%, repeating unit (c ') is 1
A liquid crystal polyester having 0 to 25 mol% and a repeating unit (d ') of 10 to 35 mol% is preferably used.

[0023] (In the formula, Ar is a divalent aromatic group.)

In the field in which the easily tearable film of the present invention requires easy disposal such as incineration after use from the viewpoint of environmental problems, it is particularly preferable among the preferred combinations of the fields required in the above. Liquid crystal polyesters comprising a combination of only carbon, hydrogen and oxygen are particularly preferably used.

The component (B) used in the liquid crystal polyester resin composition of the present invention 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 or the like may be present as a part of another functional group, and such an example includes 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 of the general formula Wherein R is a hydrocarbon group having an ethylenically unsaturated bond and having 2 to 13 carbon atoms. The unsaturated glycidyl ether is preferably a compound represented by the general formula: (R is a hydrocarbon group having 2 to 18 carbon atoms which has an ethylenically unsaturated bond, X is -CH ₂ -O- or It is. ).

Specifically, the unsaturated carboxylic acid glycidyl ester includes, for example, glycidyl acrylate, glycidyl methacrylate, itaconic acid diglycidyl ester, butenetricarboxylic acid triglycidyl ester,
Glycidyl p-styrenecarboxylate and the like can be mentioned. As unsaturated glycidyl ethers,
For example, vinyl glycidyl ether, allyl glycidyl ether, 2-methylallyl glycidyl ether, methacryl glycidyl ether, styrene-p-glycidyl ether and the like are exemplified.

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 preferred because of its higher 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 3 to 70, more preferably 3 to 30 and more preferably 4 to 30.
25 are particularly preferred. The Mooney viscosity here refers to a value measured using a large rotor at 100 ° C. according to JIS K6300.

The rubber referred to here corresponds 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).
Specific 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 The hydrogenated 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, fluoro rubber, chloroprene rubber, butyl rubber, silicone rubber, ethylene-propylene-non-conjugated diene copolymer rubber, thiol rubber, polysulfide Examples include rubber, polyurethane rubber, polyether rubber (for example, polypropylene oxide, etc.), epichlorohydrin rubber, polyester elastomer, polyamide elastomer, and the like. Among them, an acrylate-ethylene copolymer is preferably used, and a (meth) acrylate-ethylene copolymer rubber is more preferred.

These rubber-like substances are 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 invention, the copolymer (B)
Is a rubber having a functional group reactive with the liquid crystal polyester in the rubber as described above. 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 can be performed by a known method. For example, it is possible to introduce the monomer having the functional group by copolymerization at the stage of synthesizing the rubber, or it is also possible to graft copolymerize the monomer having the functional group to the 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) acrylate 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 (meth) acrylic acid ester 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 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 rubbers that can be used in the copolymer (B) of the present invention include acrylic rubber having a functional group reactive with liquid crystal polyester and vinyl aromatic having a functional group reactive with liquid crystal polyester. Hydrocarbon compounds
A conjugated diene compound block copolymer rubber can also be exemplified.

The acrylic rubber mentioned here is preferably represented by the general formula (1) (In the formula, R ¹ represents an alkyl group having 1 to 18 carbon atoms or a cyanoalkyl group.), A general formula (2) (Wherein, R ² is an alkylene group having 1 to 12 carbon atoms, R ³
Represents an alkyl group having 1 to 12 carbon atoms. ) And general formula (3) (Wherein, R ⁴ is a hydrogen atom or a methyl group, R ^{5 is} an alkylene group having 3 to 30 carbon atoms, R ⁶ is an alkyl group having 1 to 20 carbon atoms or a derivative thereof, and n is an integer of 1 to 20) .)) At least one monomer selected from the compounds represented by 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, vinylidene chloride, benzyl acrylate, methacrylic acid, itaconic acid, fumaric acid, maleic acid, and the like. .

The preferred component 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 sheet obtained from the composition are favorable, which is preferable.

The method for producing the acrylic rubber is not particularly limited. For example, JP-A-59-113010, JP-A-62-64809, and JP-A-3-160008.
Or a well-known polymerization method described in WO95 / 04764 or the like, and 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.
Examples of the conjugated diene compound include butadiene, isoprene, pyrrylene, 1,3-pentadiene, 3-butyl-1,3-octadiene and the like, 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 (meth) acrylic acid ester-ethylene-
Vulcanization of the (unsaturated carboxylic acid glycidyl ester and / or unsaturated glycidyl ether) copolymer rubber is achieved by using a polyfunctional organic acid, a polyfunctional amine compound, an imidazole compound, and the like. It is not limited.

As a specific example of the copolymer (B) having a functional group reactive with the liquid crystal polyester, the 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 methyl acrylate units. Copolymers composed of glycidyl methacrylate units and ethyl acrylate units, and copolymers composed of ethylene units, glycidyl methacrylate units and vinyl acetate units are exemplified.

The melt index of the epoxy group-containing ethylene copolymer (hereinafter sometimes referred to as MFR. JI
SK6760, 190 ° C, 2.16 kg load) is preferably 0.5 to 100 g / 10 min, more preferably 2 to 100 g / 10 min.
５０50 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 in view of the 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.

[0056] Also, 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 outside 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 carried out in the presence. 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 of the present invention comprises:
A resin composition containing the above liquid crystal polyester,
A resin composition comprising (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. If the liquid crystal polyester is not in the continuous phase, the gas barrier properties and heat resistance of the film made of the liquid crystal polyester resin composition may be significantly reduced, which is not preferable.

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 resin 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 of the present invention comprises (A) 56.0 to 99.
9% by weight, preferably 65.0 to 99.9% by weight, more preferably 70 to 98% by weight, and (B) a copolymer 4 having a functional group reactive with the liquid crystal polyester
It is a resin composition containing 4.0 to 0.1% by weight, preferably 35.0 to 0.1% by weight, more preferably 30 to 2% by weight. If the content 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 composition may be undesirably reduced. On the other hand, if the content of the component (A) exceeds 99.9% by weight, the molding processability of the composition may be reduced, and the composition is expensive, which is not preferable.

As a method for producing the liquid crystal polyester resin composition of the present invention, 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 in a molten state is preferred. For the melt kneading, kneading apparatuses 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. During the melt kneading, the cylinder set temperature of the kneading apparatus is 200
To 360 ° C, more preferably 230 ° C.
３５０350 ° 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 the components may be separately supplied to the kneading device. Methods can also be used.

In the liquid crystal polyester resin composition used in the present invention, an inorganic filler is used if desired.
Examples of 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, and aluminum borate. Examples include whiskers and potassium titanate fibers.

The liquid crystal polyester resin composition used in the present invention may further contain, if necessary, an organic filler, an antioxidant, a heat stabilizer, a light stabilizer, a flame retardant, a lubricant, an antistatic agent,
Various additives such as a rust inhibitor, 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 a manufacturing process or in a subsequent processing process. .

In order to obtain the easily tearable film of the present invention, for example, a method in which a molten liquid crystal polyester resin composition is extruded from a T-die and wound up while stretching, and a liquid crystal polyester resin composition melted from a cylindrical die is used. Is extruded, and while blowing dry air into the cylindrical resin, the sheet obtained by the inflation film forming method in which the film is wound up while being stretched, or the sheet obtained by the injection molding method or the extrusion method is further uniaxially stretched to obtain an oriented film. Examples of the method include, but are not limited to, these methods.

The easily tearable film of the present invention comprises the above liquid crystal polyester resin composition, and is a film excellent in tearability. As the easily tearable film of the present invention, the ratio of the maximum value to the minimum value of the transmitted microwave intensity measured when the film surface is irradiated with microwaves in the vertical direction by the microwave transmission method is 1 .2
Greater than, preferably greater than 1.4,
More preferably, it is greater than 1.6.

The method using a microwave molecular orientation meter referred to here is a value that reflects the interaction between the microwave and the polar molecules constituting the film by irradiating the microwave in a direction perpendicular to the film surface. It can be determined as (maximum value of transmitted microwave intensity) / (minimum value of transmitted microwave) as a scale indicating the molecular orientation of the film. When the value of (maximum value of transmitted microwave intensity) / (minimum value of transmitted microwave) in the easily tearable film of the present invention is within the above range, the tearability of the film is good, which is preferable.

The easily tearable film of the present invention is suitable for use in packaging, and can be used as an easily tearable film having excellent heat resistance, gas barrier properties, bending resistance, and tearability. Examples of the form of packaging include bags and lids. Such a packaging bag can be obtained by cutting the easily tearable film of the present invention into a predetermined size and heat-sealing it, and can be used, for example, as a packaging bag for snacks or a pouch-shaped or standing pouch-shaped bag.
Alternatively, a bag can be obtained by vacuum forming the film into a predetermined mold and then heat sealing. When used as a lid for jellies or cup noodles, the easily tearable film of the present invention can be cut into a predetermined size and heat-sealed with the cup body.

When the easily tearable film of the present invention is used as a product such as a bag or a lid, the tearing direction is the direction of the molecular orientation in the film, more specifically, the MD direction.
It is preferable to form a bag or a lid such that If the tear direction is not MD, the tearability of the film becomes poor, which is not preferable.

The thickness of the easily tearable film of the present invention is not particularly limited, but is preferably 3 to 1000 μm, more preferably 3 to 200 μm.

The easily tearable film of the present invention may have a laminated structure of two or more layers of a liquid crystal polyester resin composition layer and a liquid crystal polyester or a thermoplastic resin layer other than the liquid crystal polyester resin composition. That is, as the easily tearable film of the present invention, at least a layer composed of the liquid crystal polyester resin composition and a thermoplastic resin (however,
The liquid crystal polyester and the liquid crystal polyester resin composition are excluded. A film composed of a laminated structure having a layer consisting of

The thermoplastic resin mentioned here includes, for example, polyethylene, polypropylene, polyolefin such as ethylene-α-olefin copolymer, polystyrene,
Polyester such as polycarbonate, polyethylene terephthalate or polybutylene terephthalate, polyacetal, polyamide, polyphenylene ether, polyether sulfone, ethylene-vinyl acetate copolymer, polyvinyl chloride, polyvinylidene chloride, polyphenylene sulfide, fluorine resin, acrylic resin, etc. No. Among these, polyethylene, polypropylene,
Ethylene-α-olefin copolymer and polyethylene terephthalate are preferred. As the thermoplastic resin, one kind or a mixture of two or more kinds can be used. In addition, as a thermoplastic resin, a functional group is introduced into the molecular chain,
A modified thermoplastic resin is also used.

When the above-mentioned thermoplastic resin film is laminated on the film made of the liquid crystal polyester resin composition as the easily tearable film in the present invention, the layer made of the liquid crystal polyester resin composition is easily formed by the thermoplastic resin layer. To ensure that the tearability is not significantly reduced, for example, to form a laminate in a state where the orientation direction of the unidirectionally oriented thermoplastic resin layer and the orientation direction of the layer made of the liquid crystal polyester resin composition are almost aligned in the same direction, Alternatively, a method is preferred in which the thickness of the thermoplastic resin layer is set to such a thickness that the layer made of the liquid crystal polyester resin composition easily retains the easily tearable property.

When such a laminated structure is used for the easily tearable film, the adhesive strength between the layers may be improved by using a hot melt adhesive, a polyurethane adhesive or the like between the layers as necessary. It is possible.

The form of such a laminated structure is not particularly limited, and a liquid crystal polyester resin composition film may be formed as an outer layer and another thermoplastic resin film may be formed as an inner layer in contact with the contents. The polyester resin composition film may be sandwiched between other thermoplastic resin films on a sandwich and molded.

The surface of the easily tearable film of the present invention can be subjected to a surface treatment if necessary. Examples of such a surface treatment method include corona discharge treatment, plasma treatment, flame treatment, sputtering treatment, solvent treatment, ultraviolet treatment, infrared treatment, ozone treatment, and polishing treatment.

[0077]

The easily tearable film of the present invention has good heat resistance, moldability, gas barrier properties, flex resistance, tearability, etc., and is therefore suitable for bags, pouches, etc. of foods, beverages, detergents, medicines, pesticides, etc. , Can be used in a wide range of industries such as lids.

[0078]

EXAMPLES The present invention will be described below with reference to examples, but these are merely examples, and the present invention is not limited to these examples.

(1) Liquid Crystal Polyester of Component (A) (i) 8.3 kg (60 mol) of p-acetoxybenzoic acid, 2.49 kg (15 mol) of terephthalic acid, 0.83 kg (5 mol) of isophthalic acid and 4 5,45 kg (20.2 mol) of 4,4'-diacetoxydiphenyl was charged into a polymerization tank having a comb-shaped stirring blade, and the temperature was increased while stirring under a nitrogen gas atmosphere, and polymerization was performed at 330 ° C. for 1 hour. The acetic acid gas produced as a by-product during this period was polymerized under strong stirring while being liquefied and collected and removed by a cooling tube. Thereafter, the system was gradually cooled, and the polymer obtained at 200 ° C. was taken out of the system.
The obtained polymer was pulverized with a hammer mill manufactured by Hosokawa Micron Co., Ltd. to obtain particles of 2.5 mm or less. This is further heated at 280 ° C. in a rotary kiln under a nitrogen gas atmosphere.
For 3 hours to obtain a particulate wholly aromatic polyester having a flow temperature of 324 ° C. and comprising the following repeating structural units. Here, the flow temperature refers to a resin heated at a heating rate of 4 ° C./min using a Shimadzu Koka type flow tester model CFT-500 and a load of 100 kgf / c.
When extruded from a nozzle having an inner diameter of 1 mm and a length of 10 mm under m ² , this refers to a temperature at which the melt viscosity shows 48,000 poise. Hereinafter, the liquid crystal polyester is abbreviated as A-1. This polymer showed optical anisotropy at 340 ° C. or more under pressure. The repeating structural units of the liquid crystal polyester A-1 are as follows.

[0080]

(Ii) p-hydroxybenzoic acid 16.6k
g (12.1 mol), 8.4 kg (45 mol) of 6-hydroxy-2-naphthoic acid and 18.6 kg of acetic anhydride
(182 mol) was charged into a polymerization vessel equipped with a comb-shaped stirring blade, and the temperature was increased while stirring under a nitrogen gas atmosphere, and the polymerization was performed at 320 ° C. for 1 hour, and further at 320 ° C. for 1 hour under a reduced pressure of 2.0 torr. Was. During this time, acetic acid produced as a by-product was continuously distilled out of the system. Thereafter, the system was gradually cooled, and the polymer obtained at 180 ° C. was taken out of the system. The obtained polymer is pulverized in the same manner as in the above (A-1), and then treated in a rotary kiln under a nitrogen gas atmosphere at 240 ° C. for 5 hours, whereby the following repetitive particles having a flow temperature of 270 ° C. A unitary aromatic polyester was obtained.
Hereinafter, the liquid crystal polyester is abbreviated as A-2. This polymer showed optical anisotropy at 280 ° C. or more under pressure. The ratio of the repeating structural units of the liquid crystal polyester A-2 is as follows.

[0082]

(2) Copolymer of Component (B) In the following, E represents ethylene, MA represents methyl acrylate, GMA represents glycidyl methacrylate, and VA represents vinyl acetate.

(I) According to the method described in Example 5 of JP-A-61-127709, MA / E / GMA = 5
9.0 / 38.7 / 2.3 (weight ratio), Mooney viscosity =
15 (here, Mooney viscosity is a value measured using a large rotor at 100 ° C. according to JIS K6300) was obtained. Hereinafter, the copolymer is referred to as b-1
It may be called.

(Ii) E / VA / GMA = 83/12/5
(Weight ratio) Copolymer (manufactured by Sumitomo Chemical Co., Ltd., Bondfast 7B), MFR = 7 g / 10 min. Hereinafter, the copolymer may be abbreviated as b-2.

(3) Physical property measurement method (i) Oxygen gas permeability: Measured at a temperature of 20 ° C. in accordance with JIS K7126 A method (differential pressure method). The unit is cc / m ² · 24 hr · 1 atm.

(Ii) Water vapor transmission rate: JIS Z0208
The measurement was performed under the conditions of a temperature of 40 ° C. and a relative humidity of 90% according to the (cup method). The unit is g / m ²・ 24hr ・ 1atm
It is.

(Iii) Flex resistance: The laminated material is cut out in the MD and TD directions of the liquid crystal polyester resin composition layer.
MIT bending tester manufactured by Toyo Seiki Co., Ltd.
Folding Endurance Tester
Using the MIT-D type, a bending test is performed at a load of 1 kgf, a bending angle of 135 degrees, a bending surface curvature radius of 1 mm, and a bending speed of 175 times / min based on JIS-p-8115 until the film or sheet breaks. The number of bendings was determined.

(Iv) Molecular orientation ratio: manufactured by Shin Oji Paper Co., Ltd.
The microwave transmittance of the sample film was measured at a measurement frequency of 4 GHz using a microwave orientation evaluation device MOA-5001, and the ratio of maximum transmittance / minimum transmittance was determined as the molecular orientation ratio.

(V) Evaluation of tearing property of film: A heat sealer was used to seal four sides of the two films having aligned orientations by thermocompression bonding to prepare a bag. Tear the bag by hand along the way,
The tearability of the film was evaluated without notch according to the following criteria. ：: Can be easily torn linearly along the MD. ×: The tearing of the film is difficult, and even if it is torn, the crack does not run straight.

Example 1 85% by weight of A-1 and 15% by weight of b-1 were melted at a cylinder set temperature of 350 ° C. and a screw rotation speed of 200 rpm using a TEX-30 type twin screw extruder manufactured by Nippon Steel Corporation. The composition was obtained by kneading. The pellets of this composition were fed to a 60 mmφ single screw extruder equipped with a cylindrical die, the cylinder set temperature was 350 ° C., and the screw rotation number was 9
The melted resin is extruded at 0 rpm, the molten resin is extruded upward from a cylindrical die having a die diameter of 50 mm, a lip interval of 1.5 mm, and a die setting temperature of 350 ° C., and dry air is pressed into the hollow portion of the cylindrical film to form a cylindrical film. Is expanded and then cooled, and then passed through a nip roll to take up a winding speed of 52 m /
The film was wound in a minimum time to form an inflation film. At this time, the blow ratio was 1.7, and the thickness of the obtained film was 38 μm. When the physical properties were measured, the result of the bending test was 100,000 times or more. The oxygen permeability was 0.3 cc / m ² · atm · 24 h, and the water vapor permeability was 0.4 g / m ² · atm · 24 h. Further, the molecular orientation ratio was 1.5, and the tearability of the bag made from the film was evaluated as ○.

Comparative Example 1 Melting and kneading of a resin and formation of a film were attempted in the same manner as in Example 1 except that b-1 was not used, but no good film was obtained.

Comparative Example 2 The composition was melt-kneaded and blown in the same manner as in Example 1 except that the blow ratio in inflation film formation was set to 5.1 and the take-up speed was set to 22 m / min. Was obtained. The molecular orientation ratio of the film was 1.1. A bag was prepared from the film in the same manner as in Example 1 and its tearing property was examined.

Example 2 88% by weight of A-2 and 12% by weight of b-2 were put into a TEX-30 type twin screw extruder manufactured by Nippon Steel Corporation using a cylinder set temperature of 298 ° C. and a screw rotation speed of 180 rpm.
The melt kneading was performed at m. The obtained pellets are supplied to a 40 mm diameter single screw extruder having a cylinder set temperature of 290 ° C. and a screw rotation speed of 60 rpm, and are melt-extruded from a T-die having a die set temperature of 350 ° C., a die gap of 1.2 mm and a die width of 50 cm. Then, it is passed through a nip roll at a set temperature of 150 ° C. and wound at 45 m / min.
A 3 μm thick film was obtained. Physical properties of the obtained film were measured. The results of the bending test were 100,000 times or more, and the oxygen permeability: 0.3 cc / m ² · atm · 24 h,
The water vapor transmission rate was 0.3 g / m ² · atm · 24 h. Further, the molecular orientation ratio was 1.7, and the tearability evaluation of a bag made from the film was ○.

Comparative Example 3 Melting and kneading were carried out in the same manner as in Example 2 except that b-2 was not used, and an attempt was made to form a film. However, no good film was obtained.

Claims (22)

[Claims] 1. A liquid crystal polyester resin composition comprising (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. An easily tearable film, wherein the ratio of the maximum value to the minimum value of the transmitted microwave intensity measured when microwaves are irradiated perpendicular to the film surface is greater than 1.2. 2. A layer comprising a liquid crystal polyester resin composition comprising at least (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; An easily tearable film comprising a laminated structure having a resin (excluding the liquid crystal polyester and the liquid crystal polyester resin composition). 3. A liquid crystal polyester resin composition comprising: (A) 56.0 to 99.9% by weight of a liquid crystal polyester; and (B) a copolymer having a functional group having a reactivity with the liquid crystal polyester of 44.0 to 04.0%. 3. The easily tearable film according to claim 1, which is a composition containing 0.1% by weight. 4. A liquid crystal polyester resin composition comprising (A) 56.0 to 99.9% by weight of a liquid crystal polyester and (B) a copolymer having a functional group having a reactivity with the liquid crystal polyester of 44.0 to 04.0%. 3. The easily tearable film according to claim 1, which is a composition obtained by melt-kneading 1% by weight. 5. The easily tearable film according to claim 1, wherein the functional group reactive with the liquid crystal polyester is an oxazolyl group, an epoxy group or an amino group. 6. The easily tearable film according to claim 1, wherein the functional group reactive with the liquid crystal polyester is an epoxy group. 7. A copolymer (B) having a functional group reactive with a liquid crystal polyester, wherein the copolymer (B) contains 0.1 to 30% by weight of an unsaturated glycidyl ester unit and / or an unsaturated glycidyl ether unit. The easily tearable film according to any one of claims 1 to 4, which is a polymer. 8. The copolymer (B) having a functional group reactive with a liquid crystal polyester has a crystal heat of fusion of 3 J / g.
The easily tearable film according to any one of claims 1 to 7, wherein the copolymer is a copolymer having a molecular weight of less than or equal to. 9. The copolymer according to claim 1, wherein the Mooney viscosity of the copolymer (B) having a functional group reactive with the liquid crystal polyester is in the range of 3 to 70. Easy tear film. Mooney viscosity here is J
A value measured using a large rotor at 100 ° C. according to IS K6300. 10. The easily tearable film according to claim 1, wherein the copolymer (B) having a functional group reactive with the liquid crystal polyester is a rubber having an epoxy group. . 11. The rubber having an epoxy group comprises a (meth) acrylate-ethylene- (unsaturated carboxylic acid glycidyl ester and / or unsaturated glycidyl ether) copolymer rubber.
The easily tearable film of the above. 12. A rubber having an epoxy group, wherein the (meth) acrylate unit is more than 40% by weight and less than 97% by weight, the ethylene unit is 3% by weight or more and less than 50% by weight, the unsaturated glycidyl carboxylate unit and The easily tearable film according to claim 10, wherein the copolymer is a copolymer containing 0.1 to 30% by weight of unsaturated glycidyl ether units. 13. The (meth) acrylic ester is methyl acrylate, methyl methacrylate, n-butyl acrylate, n-butyl methacrylate, tert-butyl acrylate, tert-butyl methacrylate,
The easily tearable film according to claim 11 or 12, comprising at least one selected from -ethylhexyl acrylate and 2-ethylhexyl methacrylate. 14. The copolymer according to claim 1, wherein the copolymer (B) having a functional group reactive with the liquid crystal polyester is a thermoplastic resin having an epoxy group. Tear film. 15. A thermoplastic resin having an epoxy group,
(A) 50 to 99% by weight of ethylene units, (b) 0.1 to 30% by weight of unsaturated glycidyl ester units and / or unsaturated glycidyl ether units.
(C) 0-50 ethylenically unsaturated ester compound units
15. The easily tearable film according to claim 14, which is an epoxy group-containing ethylene copolymer in an amount of 1% by weight. 16. The easily tearable film according to claim 1, wherein the liquid crystal polyester (A) contains at least 30 mol% of the following repeating structural units. 17. The liquid crystal polyester (A) according to claim 1, wherein the polyester is obtained by reacting an aromatic dicarboxylic acid, an aromatic diol and an aromatic hydroxycarboxylic acid. The easily tearable film of the above. 18. The easily tearable film according to claim 1, wherein the liquid crystal polyester (A) is obtained by reacting a combination of different aromatic hydroxycarboxylic acids. 19. The ratio of the maximum value to the minimum value of the transmitted microwave intensity measured when the film surface is irradiated with microwaves perpendicularly by a microwave method, is greater than 1.4. Item 19. The easily tearable film according to any one of Items 1 to 18. 20. An easily tearable packaging film comprising the easily tearable film according to claim 1. 21. An easily tearable packaging bag, comprising the easily tearable film according to claim 1. 22. An easily tearable lid comprising the easily tearable film according to claim 1.