JP2810097B2 - Multilayer film - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a multilayer film comprising a liquid crystal polymer layer as a constituent element and having excellent heat resistance, gas barrier properties and the like.

[Prior Art and Problems to be Solved by the Invention] Conventionally, a polypropylene film is coated on both sides of a stretched film such as polypropylene and polyethylene terephthalate as a packaging film, or a film made of a saponified ethylene-vinyl acetate copolymer. A composite film laminated via an adhesive layer containing an acid-modified polypropylene or the like is widely used. However, the polypropylene film has insufficient oxygen gas barrier properties, and the polyethylene terephthalate film has insufficient moisture barrier properties, that is, insufficient water vapor barrier properties. Further, in the above composite film, the oxygen gas barrier property of the film composed of the saponified ethylene-vinyl acetate copolymer is remarkably reduced due to moisture absorption. For example, after retort sterilization treatment, oxygen gas barrier property is 10-40
About twice as low. Therefore, it is difficult to store foods and the like for a long period of time. Furthermore, the above-mentioned composite film is not only insufficient in heat resistance due to its constituent polymer, but also unfavorably accompanied by a polyolefin odor particularly when heated.

A composite film in which a polypropylene film is laminated on both sides of a polyvinylidene chloride film via a layer made of an ethylene-vinyl acetate copolymer has also been proposed. According to this composite film, a polyvinylidene chloride film can secure oxygen gas barrier properties, and a polypropylene film can secure water vapor barrier properties. However, since a plasticizer or a stabilizer is usually added to polyvinylidene chloride to impart moldability, gas barrier properties are reduced.
In addition, since the glass transition temperature of polyvinylidene chloride is low,
As the temperature increases, plasticization occurs, the gas barrier property at high temperatures decreases as described above, and the heat resistance is insufficient due to the constituent polymers.

On the other hand, polybutylene terephthalate and the like are known as films having excellent heat resistance. Therefore, it is conceivable to laminate the film and the polyvinylidene chloride film. However, since the melting point and the decomposition temperature of polyvinylidene chloride are close to each other and decompose at about 180 to 200 ° C., it is difficult to form a laminated film by coextrusion with polybutylene terephthalate having excellent heat resistance.

Accordingly, an object of the present invention is to provide a multilayer film which has excellent heat resistance, has no polyolefin odor even when exposed to high temperature and high humidity, maintains excellent gas barrier properties, and can be used for various applications.

[Constitution of the Invention] The present inventors have found that a thermotropic liquid crystalline polymer exhibits a high gas barrier property, and as a result of earnestly studying the formation of a film, the present invention has been completed. That is, the present invention solves the above-mentioned problems by a multilayer film in which a polyalkylene terephthalate layer is laminated on both sides of a liquid crystalline polymer layer containing a thermotropic liquid crystalline polymer via an adhesive layer. The adhesive layer is
It is composed of the following specific modified polyolefin or polyester.

In the present specification, the liquid crystalline polymer means a thermotropic liquid crystal polymer and a composition thereof which are softened and flowable by heating, can be molded, and exhibit an anisotropic molten phase having birefringence when melted.

Also, a film is used to include all relatively thin, substantially flat structures that are sometimes referred to in the art as sheets or the like.

Examples of the above liquid crystalline polymer include polymers composed of the following components and the like.

(1) One or two or more aromatic digalbonic acids and alicyclic dicarboxylic acids (2) One or two or more aromatic diols, alicyclic diols, and aliphatic diols (3) One aromatic hydroxycarboxylic acid (4) One or more aromatic thiolcarboxylic acids (5) One or more aromatic diols and aromatic thiol phenols (6) One or two aromatic hydroxyamines and aromatic diamines More than species.

Examples of the liquid crystalline polymer composed of the above components include: i) a polyester composed of the components (1) and (2); ii) a polyester composed of the component (3); iii) a polyester composed of the components (1) and (2). Iv) a polythiol ester consisting of component (4), v) a polythiol ester consisting of components (1) and (5), vi) a component (1), (4) and (4) Vii) a polyester amide comprising components (1), (3) and (5); viii) a polythiol ester comprising components (1), (2), (3) and (5) Is selected as a combination of the following polyesteramides.

Although not included in the category of the combination of the above components, such a liquid crystalline polymer includes an aromatic polyazomethine, and specific examples thereof include poly (nitrilo-2-methyl-1,4
Phenylenenitroethylidine-1,4-phenyleneethylidine), poly (nitrilo-2-methyl-1,4-phenylenenitrilomethylidyne-1,4-phenylenemethylidyne), and poly (nitrilo-2-chloro- 1,4-phenylenenitromethylidine-1,4-phenylenemethylidine)
And the like.

Further, although not included in the category of the combination of the above components, such a liquid crystalline polymer includes polyester carbonate. This polymer essentially contains 4-oxybenzoyl, dioxyphenyl, dioxycarbonyl and terephthaloyl units.

As the aromatic dicarboxylic acid, terephthalic acid, 4,
4'-diphenyldicarboxylic acid, 4,4 "-triphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, diphenylether-4,4'-dicarboxylic acid, diphenoxyethane-4,4'-dicarboxylic acid, diphenoxybutane −4,4 ′
-Dicarboxylic acid, diphenylethane-4,4'-dicarboxylic acid, isophthalic acid, diphenylether-3,3'-dicarboxylic acid, diphenoxyethane-3,3'-dicarboxylic acid, diphenylethane-3,3'-dicarboxylic acid Aromatic dicarboxylic acids such as, naphthalene-1,6-dicarboxylic acid;
Alkyl, alkoxy or halogen-substituted aromatic dicarboxylic acids, such as chloroterephthalic acid, dichloroterephthalic acid, bromoterephthalic acid, methylterephthalic acid, dimethylterephthalic acid, ethylterephthalic acid, methoxyterephthalic acid, ethoxyterephthalic acid and the like. .

Examples of the alicyclic dicarboxylic acid include trans-1,4-cyclohexanedicarboxylic acid, cis-1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, and other alicyclic dicarboxylic acids; alkyls of alicyclic dicarboxylic acids ,
Alkoxy or halogen substituents such as trans-
Examples thereof include 1,4- (1-methyl) cyclohexanedicarboxylic acid and trans-1,4- (1-chloro) cyclohexanedicarboxylic acid.

As aromatic diols, hydroquinone, resorcinol, 4,4'-dihydroxydiphenyl, 4,4 "-dihydroxytriphenyl, 2,6-naphthalenediol, 4,4'-
Dihydroxydiphenyl ether, bis (4-hydroxyphenoxine) ethane, 3,3'-dihydroxydiphenyl, 3,3'-dihydroxydiphenyl ether, 1,6-
Aromatic diols such as naphthalene diol, 2,2-bis (4-hydroxyphenyl) propane and 1,1-bis (4-hydroxyphenyl) methane; alkyl, alkoxy or halogen-substituted aromatic diols such as chlorohydroquinone , Methylhydroquinone, 1-butylhydroquinone, phenylhydroquinone, methoxyhydroquinone, phenoxyhydroquinone, 4-chlororesorcin, 4-methylresorcin, and the like.

As the alicyclic diol, trans-1,4-cyclohexanediol, cis-1,4-cyclohexanediol, trans-1,4-cyclohexanedimethanol, trans-1,3-cyclohexanediol, cis-1,2- Alicyclic diols such as cyclohexanediol and trans-1,3-cyclohexanedimethanol; alkyl, alkoxy or halogen-substituted alicyclic diols such as trans-1,4- (1-methyl) cyclohexanediol, trans- 1,4- (1-chloro) cyclohexanediol and the like can be mentioned.

As the aliphatic diol, ethylene glycol, 1,3
-Linear or branched aliphatic diols such as propanediol, 1,4-butanediol and neopentyl glycol.

Examples of the aromatic hydroxycarboxylic acid include aromatic hydroxycarboxylic acids such as 4-hydroxybenzoic acid, 3-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, and 6-hydroxy-1-naphthoic acid; aromatic hydroxycarboxylic acids Alkyl, alkoxy or halogen substituents of
For example, 3-methyl-4-hydroxybenzoic acid, 3,5-
Dimethyl-4-hydroxybenzoic acid, 2,6-dimethyl-
4-hydroxybenzoic acid, 3-methoxy-4-hydroxybenzoic acid, 3,5-dimethoxy-4-hydroxybenzoic acid, 6-hydroxy-5-methyl-2-naphthoic acid, 6
-Hydroxy-5-methoxy-2-naphthoic acid, 3-chloro-4-hydroxybenzoic acid, 2,3-dichloro-4-
Hydroxybenzoic acid, 3,5-dichloro-4-hydroxybenzoic acid, 2,5-dichloro-4-hydroxybenzoic acid,
3-bromo-4-hydroxybenzoic acid, 6-hydroxy-5-chloro-2-naphthoic acid, 6-hydroxy-7-
Chloro-2-naphthoic acid, 6-hydroxy-5,7-dichloro-2-naphthoic acid and the like can be mentioned.

Examples of the aromatic mercaptocarboxylic acid include 4-mercaptobenzoic acid, 3-mercaptobenzoic acid, 6-mercapto-2-naphthoic acid, and 7-mercapto-2-naphthoic acid.

As aromatic dithiols, benzene-1,4-dithiol, benzene-1,3-dithiol, naphthalene-2,6-
Dithiol, naphthalene-2,7-dithiol and the like.

Examples of the aromatic mercaptophenol include 4-mercaptophenol, 3-mercaptophenol, and 2-mercaptophenol.

As aromatic hydroxyamine and aromatic diamine,
4-aminophenol, N-methyl-4-aminophenol, 1,4-phenylenediamine, N-methyl-1,4-phenylenediamine, N, N'-dimethyl-1,4-phenylenediamine, 3-aminophenol 3-methyl-4-aminophenol, 2-chloro-4-aminophenol,
4-amino-1-naphthol, 4-amino-4'-hydroxydiphenyl, 4-amino-4'-hydroxydiphenyl ether, 4-amino-4'-hydroxydiphenylmethane, 4-amino-4'-hydroxydiphenyl sulfide, 4 4,4'-diaminophenyl sulfide (thiodianiline), 4,4'-diaminodiphenyl sulfone, 2,5-diaminotoluene, 4,4'-ethylenedianiline, 4,4'-diaminodiphenoxyethane, 4,4 ' -Diaminodiphenylmethane (methylenedianiline), 4,4 '
-Diaminodiphenyl ether (oxydianiline) and the like.

The polymers i) to vii comprising the above components
i) is a polymer having no birefringence at the time of melting depending on the constituent components, the composition ratio in the polymer, and the sequence distribution, but the polymer used in the present invention is one of the above polymers having birefringence at the time of melting. Limited.

The liquid crystalline polymer used in the present invention can be produced by a conventionally known method.

The wholly aromatic polymers preferably used in the present invention tend to be substantially insoluble in common solvents and are therefore unsuitable for solution processing. However, these polymers can be easily processed by conventional melt processing methods. It should be noted that particularly preferred fully aromatic polymers are somewhat soluble in pentafluorophenol.

The liquid crystalline polymer used in the present invention may have an appropriate molecular weight as long as film formability and the like are not impaired. For example, suitable fully aromatic polyesters usually have a weight average molecular weight of about 2,000 to 200,000, preferably about 10,000 to 50,000.
0, particularly preferably about 20,000 to 25,000. Suitable wholly aromatic polyesteramides typically have a molecular weight of about
5,000 to 50,000, preferably about 10,000 to 30,000, for example, 15,000 to 17,000. The determination of molecular weight can be carried out by gel permeation chromatography as well as other standard methods without melt formation of the polymer, for example by quantifying end groups by infrared spectroscopy on compression molded films. The molecular weight can also be measured using a pentafluorophenol solution and using a light scattering method.

The wholly aromatic polyester amide described above, when dissolved in pentafluorophenol at a temperature of 60 ° C. at a concentration of 0.1% by weight, has at least about 2.0 dl / g, for example, about 2.0 to 10.0 dl / g.
Logarithmic viscosity (IV) is generally indicated.

Particularly preferred polyesters forming an anisotropic molten phase include naphthalene partial units such as 6-hydroxy-2-naphthoyl, 2,6-dihydroxynaphthalene and 2,6-dicarboxynaphthalene in an amount of about 10 mol% or more. I do.
Preferred polyesteramides are those containing repeating units of the naphthalene moiety and a moiety consisting of 4-aminophenol or 1,4-phenylenediamine. Specifically, it is as follows.

(A) a polyester consisting essentially of the following repeating units I and II: The polyester contains about 10-90 mol% of unit I and about 10-90 mol% of unit II. In one embodiment the unit I
Is present in an amount of about 65-85 mol% (e.g., about 75 mol%). In other embodiments, Unit II is present in a low amount of about 15-35 mol%, preferably about 20-30 mol%. At least a part of the hydrogen atoms bonded to the ring is substituted with a substituent selected from the group consisting of an alkoxy group having 1 to 4 carbon atoms, a halogen atom, a phenyl group, a substituted phenyl group, and combinations thereof. You may.

(B) a polyester consisting essentially of the following repeating units II, III and IV: This polyester contains about 30-70 mol% of unit II. The polyester preferably has units II of about 40 to
60 mol%, unit III is about 20-30 mol%, and unit IV is about 20
-30% by mole. At least a part of the hydrogen atoms bonded to the ring is substituted by a substituent selected from the group consisting of an alkoxy group having 1 to 4 carbon atoms, a halogen atom, a phenyl group, a substituted phenyl group, and a combination thereof. You may.

(C) a polyester consisting essentially of the following repeating units II, IV, V and VI: Wherein R represents a methyl group, chloro, bromo or a combination thereof, and is a substituent for a hydrogen atom on an aromatic ring.
IV is about 5 to 35 mol%, unit V is about 5 to 18 mol% and unit
Contains about 20-40 mol% VI. The polyester preferably has a unit II of about 35-45 mol% and a unit IV of about 15-25
Mol%, unit V is about 10-15 mol%, and unit VI is about 25-35.
Mol%. However, the total molarity of the units IV and V is substantially equal to the molarity of the unit VI. Further, at least a part of the hydrogen atoms bonded to the ring is a group consisting of an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a halogen atom, a phenyl group, a substituted phenyl group, and a combination thereof. May be substituted by a substituent selected from The wholly aromatic polyester generally exhibits a logarithmic viscosity of at least 2.0 dl / g, for example, 2.0 to 10.0 dl / g when dissolved in pentafluorophenol at a temperature of 60 ° C. at a concentration of 0.3 W / V%.

(D) a polyester consisting essentially of the following repeating units I, II, VII and VIII: A dioxyaryl unit represented by the general formula O-Ar-O VII (wherein, Ar represents a divalent group containing at least one aromatic ring) (Wherein Ar is the same as described above). The polyester has about 20 to 40 mol% of unit I,
II in excess of 10 mol%, up to about 50 mol%, unit VII in excess of 5 mol%, up to about 30 mol%, and unit VIII in 5 mol%
And in an amount up to about 30 mol%. The polyester preferably comprises about 20 to 30 mole% of unit I, for example about 25 mole%, and unit II for about 25 to 40 mole%, for example about
It contains 35 mol%, about 15 to 25 mol% of unit VII, for example, about 20 mol%, and about 15 to 25 mol% of unit VIII, for example, about 20 mol%. Further, at least a part of the hydrogen atoms bonded to the ring is an alkyl group having 1 to 4 carbon atoms,
4 may be substituted with a substituent selected from the group consisting of an alkoxy group, a halogen atom, a phenyl group, a substituted phenyl group, and combinations thereof.

Units VII and VIII may have one or two divalent bonds linking these units to other units on either side of the polymer backbone.
It is preferable to be symmetrical in the sense that they are symmetrically arranged on the above aromatic ring (for example, when they are present on a naphthalene ring, they are arranged in a para position or on a diagonal ring). . However, asymmetric units such as those derived from resorcinol and isophthalic acid can also be used.

Preferred dioxyaryl units VII are And a preferred dicarboxyaryl unit VIII is It is.

(E) a polyester consisting essentially of the following repeating units I, VII, VIII: A dioxyaryl unit represented by the general formula O-Ar-O VII (wherein Ar is as defined above) (Wherein Ar is the same as described above). The polyester has a unit I of about 10 to 90 mol%,
It contains 5 to 45 mol% of VII and 5 to 45 mol% of unit VIII. The polyester preferably has units I of about
20-80 mol%, about 10-40 mol% of unit VII and unit VIII
About 10 to 40 mol%. More preferably, the polyester contains about 60-80 mol% of unit I, about 10-20 mol% of unit VII, and about 10-20 mol% of unit VIII. At least a part of the hydrogen atoms bonded to the ring is selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a halogen atom, a phenyl group, a substituted phenyl group, and a combination thereof. It may be substituted with a selected substituent.

Preferred dioxyaryl units VII are And a preferred dicarboxyaryl unit VIII is It is.

(F) a polyesteramide consisting essentially of the following repeating units I, IX, X and VII: (Wherein, A represents a divalent group containing at least one aromatic ring or a divalent trans-cyclohexane group) General formula Y-Ar-Z X (wherein, Ar is as defined above). Y is O, NH or NR, Z is NH
Or NR, and R represents an alkyl group or an aryl group having 1 to 4 carbon atoms.) A unit represented by the general formula O-Ar-O VII (wherein Ar is as defined above) Carboxyaryl Units The polyesteramide contains about 10-90 mol% of unit I, 5-45 mol% of unit IX, 5-45 mol% of unit X, and about 0-40 mol% of unit VII. I do. At least a part of the hydrogen atoms bonded to the ring has 1 to 1 carbon atoms.
It may be substituted by a substituent selected from the group consisting of an alkyl group having 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a halogen atom, a phenyl group, a substituted phenyl group, and combinations thereof.

Preferred dicarboxyaryl units IX are And a preferred unit X is And a preferred dioxyaryl unit VII is It is.

Further, in the polymer forming the anisotropic melt phase of the present invention, a part of one polymer chain is composed of a segment of the polymer forming the anisotropic melt phase, and the remaining part is anisotropic melt phase. Also, a polymer composed of a segment of a thermoplastic resin that does not form a polymer is included.

The liquid crystalline polymer has not only excellent gas barrier properties at room temperature but also excellent heat resistance, and thus has no temperature dependence of gas barrier properties. That is, even when subjected to high temperature, for example, retort sterilization, the gas barrier property and the water vapor barrier property do not decrease. The heat distortion temperature of the liquid crystalline polymer is usually 80 to 400 ° C, preferably about 120 to 350 ° C. In particular, a liquid crystalline polymer having a heat deformation temperature of 150 to 250 ° C. is preferable because of excellent film-forming properties. The oxygen gas permeability and water vapor permeability of the liquid crystalline polymer is usually 1.0cc / m ² · 25μm ·
It is less than 24 hours and atmospheric pressure.

The liquid crystalline polymer is contained in the liquid crystalline polymer layer at least 50% by weight, preferably 75% by weight or more.

The melt-processable polymer composition that forms the anisotropic melt phase used in the present invention includes other polymers that form the anisotropic melt phase, thermoplastic resins that do not form the anisotropic melt phase, and thermosetting. It may contain at least one of a resin, a low molecular organic compound, and an inorganic substance. The polymer forming the anisotropic molten phase in the composition and other components may be thermodynamically compatible.

As the above thermoplastic resin, for example, polyethylene, polypropylene, polybutylene, polybutadiene,
Polyisoprene, polyvinyl acetate, ethylene-vinyl acetate copolymer, ethylene-acrylate copolymer,
Ethylene-methacrylic acid ester copolymer, ionomer, polyvinyl chloride, polyvinylidene chloride, polystyrene, acrylic resin, ABS resin, AS resin, BS resin, polyurethane, silicone resin, fluororesin, polyacetal, polycarbonate, polyethylene terephthalate,
Polybutylene terephthalate, aromatic polyester, polyamide, polyacrylonitrile, polyvinyl alcohol, polyvinyl ether, polyetherimide, polyamideimide, polyetheretherimide, polyetheretherketone, polyethersulfone, polysulfone, polyphenylene sulfide, polyphenylene oxide Etc. are included.

Examples of the thermosetting resin include a phenol resin, an epoxy resin, a melamine resin, a urea resin, an unsaturated polyester resin, a diallyl phthalate resin, and an alkyd resin.

As the low-molecular-weight organic compound, for example, substances usually added to thermoplastic resins and thermosetting resins, that is, weathering and light-resistant stabilizers such as plasticizers, antioxidants and ultraviolet absorbers, antistatic agents, Flame retardants, coloring agents such as dyes and pigments,
It includes a foaming agent, a divinyl compound, a crosslinking agent such as a peroxide and a vulcanizing agent, and a low molecular weight organic compound used as a lubricant for improving fluidity and releasability.

Further, as the above-mentioned inorganic substance, for example, a substance usually added to a thermoplastic resin and a thermosetting resin, that is,
General inorganic fibers such as glass fiber, carbon fiber, metal fiber, ceramic fiber, boron fiber, and asbestos, calcium carbonate, highly dispersible silica, alumina, aluminum hydroxide,
Powdered substances such as talc powder, mica, glass flakes, glass beads, quartz powder, quartz sand, various metal powders, carbon black, barium sulfate, calcined gypsum and the like, and inorganic compounds such as silicon carbonate, boron nitrite and silicon nitride, Whiskers and metal whiskers are included.

The thickness of the liquid crystal polymer layer containing the liquid crystal polymer is not particularly limited, but is usually about 1 to 500 μm, preferably about 5 to 250 μm, and more preferably about 10 to 150 μm.

In the multilayer film of the present invention, a polyalkylene terephthalate layer is laminated on both sides of the liquid crystalline polymer layer via an adhesive layer.

Examples of the polyalkylene terephthalate include those having an alkylene group having about 2 to 6 carbon atoms, those having a cycloalkylene group or an ether group in a part of the alkylene group, particularly polyethylene terephthalate, and polyalkylene terephthalate having high heat resistance. For example, so-called PET-G or polybutylene terephthalate obtained by substituting a part of ethylene glycol with 1,4-cyclohexanedimethanol, diethylene glycol or the like is preferable. The polyalkylene terephthalate having high heat resistance can be easily coextruded with the liquid crystalline polymer.

Note that a plurality of the same or different polyalkylene terephthalate layers may be stacked. Also, by laminating a liquid crystalline polymer layer and a polyalkylene terephthalate layer,
Gas barrier properties such as oxygen gas barrier properties can be further enhanced, and heat resistance is excellent.

The thickness of the polyalkylene terephthalate layer is not particularly limited, but is usually about 1 to 50 μm.

Further, the adhesive layer contains a modified polyolefin or polyester exhibiting excellent adhesiveness to the liquid crystalline polymer layer and the polyalkylene terephthalate layer.

As the modified polyolefin, a modified polyolefin into which at least one functional group selected from a glycidyl group and an alkoxysilane group is introduced is used. Examples of such modified polyolefins include glycidyl-modified polyolefin, alkoxysilane-modified polyolefin, glycidyl-modified ethylene-ethyl acrylate copolymer, alkoxysilane-modified ethylene-ethyl acrylate copolymer, glycidyl-modified ethylene-vinyl acetate copolymer, and alkoxy. Examples thereof include a silane-modified ethylene-vinyl acetate copolymer.

The modified polyolefin may have other functional groups introduced therein, for example, a hydroxy group, an alkoxy group, an alkoxycarbonyl group, an amino group, etc., particularly a carboxy group.
These functional groups may be used in combination. Further, the modified polyolefin used in the present invention may be used as a layer adjacent to an adhesive layer in combination with the modified polyolefin into which the other functional group has been introduced. Examples of such modified polyolefin include carboxy-modified polyolefin, carboxy-modified ethylene-ethyl acrylate copolymer, carboxy-modified ethylene-vinyl acetate copolymer, and the like.

The carboxy-modified, glycidyl-modified, and alkoxysilane-modified include, for example, an unsaturated carboxylic acid such as acrylic acid and maleic anhydride or an acid anhydride thereof; a polymerizable unsaturated compound having a glycidyl group such as glycidyl acrylate and glycidyl methacrylate; It means that it has been modified with a polymerizable unsaturated compound having an alkoxysilane group such as methacryloxypropyltrimethoxysilane.

Further, the polyester has a polyvalent carboxylic acid, a polyhydric alcohol, a hydroxycarboxylic acid as a component,
If necessary, small amounts of monohydric carboxylic acids and monohydric alcohols are used.

As polyvalent carboxylic acids, divalent or higher carboxylic acids, for example, oxalic acid, maleic acid, maleic anhydride, succinic acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanoic acid and the like Polyvalent carboxylic acid; alicyclic polycarboxylic acid such as 1,4-cyclohexanedicarboxylic acid; phthalic acid, phthalic anhydride, terephthalic acid, isophthalic acid, trimellitic acid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride Examples thereof include aromatic polycarboxylic acids such as melitic acid, trimesic acid, naphthalene-2,6-dicarboxylic acid, diphenyl-4,4'-dicarboxylic acid, and 3-sulfoisophthalic acid. These polycarboxylic acids can be used as a mixture of one or more kinds. In the present invention, 30 to 80 mol% of terephthalic acid and 70 to 20 mol% of dicarboxylic acid selected from adipic acid, sebacic acid and isophthalic acid are used as the polycarboxylic acid component.

As the polyhydric alcohol, dihydric or higher alcohols, for example, ethylene glycol, diethylene glycol,
Triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, trimethylene glycol, 1,4-butanediol, 1,3-butanediol, 1,5-pentanediol, 1,6- Aliphatic polyhydric alcohols such as hexanediol, neopentyl glycol, glycerol, trimethylolpropane, and pentaerythritol; resorcinol, 2,2-bis (4-hydroxyphenyl) propane, 4,4'-bis (2-hydroxyethyl) Such as phenyl-2,2-propane, 4,4'-bis (2-hydroxypropyl) phenyl-2,2-propane and 4,4'-bis (2-hydroxyethoxyethyl) phenyl-2,2-propane Aromatic polyhydric alcohols are exemplified. These polyhydric alcohols can be used by mixing one or more kinds. In the present invention, ethylene glycol and 1,4
-A diol component containing at least one of butanediol is used. In particular, 1,4-butanediol is preferred.

Examples of the hydroxycarboxylic acid include aliphatic hydroxycarboxylic acids such as glycolic acid and oxypropionic acid; and aromatic hydroxycarboxylic acids such as hydroxybenzoic acid, which may be used in combination of one or more.

Incidentally, the polyester referred to here, other polymers having a component of the polyester as a segment component,
For example, polyester ether, polyester amide,
Polyester carbonate and the like are also included.

These modified polyolefins and polyesters are used alone or in combination of two or more. Also, the adhesive layer
It contains at least 50% by weight, preferably at least 75% by weight of the above modified polyolefin and / or polyester.

At least one adhesive layer between the layers may be formed, and a plurality of layers may be formed as necessary. The thickness of the adhesive layer is not particularly limited as long as the adhesiveness is not impaired, but usually, about 0.1 to 50 μm can secure sufficient adhesiveness.

Further, the polyalkylene terephthalate layer and the adhesive layer may contain the above-mentioned thermoplastic resin, a low molecular organic compound, a tackifier, a wax, an inorganic substance, and the like.

The multilayer film of the present invention is not limited to a conventional method such as a dry laminating method and an extrusion laminating method.Because the melting point of a liquid crystalline polymer is high, a multilayer molding method of co-extruding with a polyalkylene terephthalate or a combination thereof is used. It can be formed by a method. As the co-extrusion multi-layer molding method, any of a multi-manifold method in which the layers are merged in a die and a feed block method can be adopted.
At the time of laminating, a corona discharge treatment, a sputtering treatment, a high-frequency treatment, a flame treatment, a chromic acid treatment, a solvent etching treatment, an undercoat treatment, or a combination of these surface treatments may be performed.

Further, the multilayer film of the present invention may be monoaxially or biaxially stretched to an appropriate magnification by stretching means such as roll stretching, belt stretching, tenter stretching, and tube stretching. Note that at least one of the liquid crystal polymer layer and the polyalkylene terephthalate layer may be stretched.

The multilayer film of the present invention can be used as a film for individual packaging, interior, exterior, and bag making of various articles to be packaged. For example,
Excellent in oxygen gas barrier and water vapor barrier properties, so it is used as conventional food packaging film, packaging material for oily cooking material, packaging material for medicine, packaging material for cosmetics, and fragrance-retaining packaging material for aromatic substances. it can. Also under high temperature, for example temperature
Since it exhibits resistance even at about 180 ° C. and has no polyolefin odor, it is suitable as a field in which gas barrier properties are required especially at high temperatures, for example, food packaging materials such as retort foods and foods for microwave ovens.

[Effects of the Invention] As described above, according to the multilayer film of the present invention, a polyalkylene terephthalate layer is laminated on both surfaces of a liquid crystalline polymer layer containing a thermotropic liquid crystalline polymer via a specific adhesive layer. Therefore, it has excellent heat resistance, has no polyolefin odor even when exposed to high temperature and high humidity, and has excellent gas barrier properties.

EXAMPLES Hereinafter, the present invention will be described in more detail based on examples.

Example 1 Polybutylene terephthalate (PBT) (manufactured by Polyplastics Co., Ltd., intrinsic viscosity 1.0 dl / g measured in orthochlorophenol at a temperature of 25 ° C.), glycidyl-modified ethylene-vinyl acetate copolymer (a) (Sumitomo) Chemical Industry Co., Ltd.
(Trade name Bond Fast 7B), liquid crystal polymer (b) composed of polyester (A) composed of the above repeating units I and II (Vectra A9, trade name, manufactured by Polyplastics Co., Ltd.)
Is fed to a feed block type multilayer molding apparatus, and is co-extruded into five layers to obtain (PBT) / (a) /
(B) / (a) / (PBT) = 25/10/30/10/25 μm multilayer films were produced.

Example 2 Polybutylene terephthalate (PBT) of Example 1 and maleic anhydride-modified ethylene-ethyl acrylate copolymer (c) (trade name: Bondine TX80, manufactured by Sumitomo Chemical Co., Ltd.)
30), glycidyl-modified polyethylene (d) (manufactured by Nippon Oil Co., Ltd., trade name: Lexpearl J-3700), and the liquid crystal polymer (b) of Example 1 were used to form 7 layers in the same manner as Example 1. Extrusion molding, (PBT) / (c) / (d) / (b) /
(D) / (c) / (PBT) = 20/10/10/30/10/10/20 μm
Was produced.

Example 3 Polybutylene terephthalate (PBT) of Example 1, an alkoxysilane-modified ethylene-ethyl acrylate copolymer (e) (trade name: HPR AS252, manufactured by DuPont-Mitsui), liquid crystal polymer of Example 1 (b) And co-extruded into five layers in the same manner as in Example 1 to obtain (PBT) / (e) /
(B) / (e) / (PBT) = 25/10/30/10/25 μm multilayer film was produced.

Example 4 Instead of the polybutylene terephthalate of Example 1, polyethylene terephthalate (PET-G) in which a part of the glycol component was replaced with 1,4-cyclohexanedimethanol
(Eastman Chemical Products, trade name PE
Using T-G6763), five layers were co-extruded in the same manner as in Example 1, and (PET-G) / (a) / (b) / (a)) / (P
(ET-G) = 25/10/30/10/25 μm multilayer films were produced.

Example 5 Example 1 was performed using the maleic anhydride-modified ethylene-ethyl acrylate copolymer (c) of Example 2, the glycidyl-modified polyethylene (d) of Example 2, and the liquid crystalline polymer (b) of Example 1. Co-extrusion into 5 layers in the same manner as in (c)
/ (D) / (b) / (d) / (c) = 10/10/30/10 / 10μ
m was prepared.

Next, stretched polyethylene terephthalate (PET) (trade name: E5100, manufactured by Toyobo Co., Ltd.) having a thickness of 12 μm and subjected to corona discharge treatment was heat-laminated on the adhesive layers (c) on both surfaces of the multilayer film, respectively (PET). ) / (C) /
(D) / (B) / (D) / (C) / (PET) = 12/10/10 /
A 30/10/10/12 μm multilayer film was produced.

Comparative Example 1 Polypropylene (PP) (manufactured by Sumitomo Chemical Co., Ltd., trade name: Noblen FL6315G), maleic anhydride-modified polypropylene (f) (manufactured by Mitsubishi Yuka Co., Ltd., Modec P310K),
Using a saponified ethylene-vinyl acetate copolymer (g) (manufactured by Solvay Co., Ltd., trade name: Clarane L6), it was co-extruded into five layers in the same manner as in Example 1, and (PP) / (f) / (g ) /
(F) / (PP) = 25/10/30/10/25 μm multilayer film was produced.

Comparative Example 2 Polypropylene (PP), ethylene-vinyl acetate copolymer (EVA) (trade name: Evaflex P1905, manufactured by Du Pont-Mitsui Co., Ltd.) of Comparative Example 1, and a polyvinylidene chloride copolymer (vinylidene chloride content 90) Resin composition comprising 5 parts by weight of an epoxy resin, 5 parts by weight of dityl sebacate as a plasticizer, and 0.3 parts by weight of stearic acid as a lubricant based on 100 parts by weight of 100 parts by weight or more of methyl acrylate content of 10% by weight or less. Using PVCD), co-extrusion molding into 5 layers was performed in the same manner as in Example 1, and (PP) / (EVA) / (PVDC) / (EVA) /
(PP) = A multilayer film of 25/10/30/10/25 μm was produced.

Then, odor, fragrance retention, oxygen gas permeability, water vapor permeability, and oxygen gas permeability after retort sterilization were examined by the following test methods.

Odor The four sides were impulse-sealed, water was poured into a bag having a hole for vapor release, heated in a microwave oven for 5 minutes, and the presence or absence of a polyolefin odor was evaluated by a sensory test according to the following criteria.

○: No polyolefin odor ×: Polyolefin odor Scent retention To prevent leakage from the seal part, seal it at two places at predetermined intervals on each side with a seal width of 15 mm and 5 ml of methyl salicylate using an impulse sealer. Make a 100mm x 100mm bag to hold the temperature, temperature 40 ℃, relative humidity 90%
Was allowed to stand for 30 days, and the weight loss rate was measured.

ASTM D-39 using a carrier gas consisting of 98% nitrogen gas and 2% hydrogen gas under the conditions of an oxygen gas permeability of 23 ° C and a relative humidity of 60%.
It was measured by the isobaric method according to 85-81.

Water vapor permeability Measured under the conditions of a temperature of 25 ° C. and a relative humidity of 90% using air as a carrier gas and an infrared sensor according to ASTM F-372-73.

Oxygen gas transmission rate after retort sterilization treatment Immerse in pressurized hot water at a temperature of 120 ° C for 30 minutes, and then measure at a temperature of 20 ° C and a relative humidity of 40% according to the above-described method for measuring the oxygen gas transmission rate. did.

 The results are shown in the table.

As is clear from the table, compared to the film of the comparative example,
Each of the films of Examples had no polyolefin odor when heated, and the weight loss of methyl salicylate was less than 0.1% by weight. Thus, the films were excellent in fragrance retention, oxygen gas barrier properties and moisture proof properties. Further, it was found that the gas barrier properties of the film of Comparative Example 1 were significantly reduced by the heating and humidification treatment, whereas the gas barrier properties of the films of Examples were hardly reduced.

Continuation of the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B32B 7/00-27/42 B65D 65/40 C09J 123/00-133/26 C08J 5/12

Claims (1)

(57) [Claims] 1. A multilayer film in which a polyalkylene terephthalate layer is laminated on both sides of a liquid crystalline polymer layer containing a thermotropic liquid crystalline polymer via an adhesive layer, wherein the adhesive layer comprises (1) a glycidyl-modified polyolefin. And at least one modified polyolefin selected from alkoxysilane-modified polyolefins, or (2)
30 to 80 mol% of terephthalic acid and 70 to 20 mol% of dicarboxylic acid selected from adipic acid, sebacic acid and isophthalic acid, and at least one of ethylene glycol and 1,4-butanediol A multilayer film comprising a polyester obtained by a reaction with a diol component.