JPH09323389A - Laminated polyamide film and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a film having excellent antistatic properties, satisfactory transparency and easy slipperiness by laminating an antistatic layer containing graft copolymer made of polyester having antistatic agent and acrylic polymer as a main component on one side surface of a polyamide film. SOLUTION: At least one side surface of an unoriented or uniaxially oriented polyamide film is coated with coating liquid containing graft copolymer made of polyester containing antistatic agent and acrylic polymer or graft copolymer made of polyurethane and acrylic polymer as a main component. Then, this film is oriented to obtain a laminated polyamide film having satisfactory transparence and easy slipperiness. The agent in the antistatic layer is compound made of 8-13C alkyl residue, aromatic residue and sodium sulfonate salt.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated polyamide film having excellent antistatic properties, excellent transparency and slipperiness, and a method for producing the same.

[0002]

2. Description of the Related Art Generally, polyamide films are excellent in mechanical properties, optical properties, thermal properties, gas barrier properties, toughness, pinhole resistance, flex resistance, etc. and are widely used mainly in the food packaging field. ing. However, the conventional polyamide film is inferior in antistatic property, various troubles caused by charging the film, for example, winding failure, pitch deviation of printing due to meandering of the film, occurrence of beard during printing, etc. Was strongly desired. As a method for solving these drawbacks, a polyamide film in which a low molecular weight antistatic agent such as a surfactant is blended with the base of the polyamide film to impart antistatic properties has been investigated.

[0003]

However, in the above polyamide film, the heat resistance of the antistatic agent is insufficient, the compatibility of the antistatic agent and the polyamide is reduced, and the die lip portion at the sheet extrusion molding is formed. There is a problem of film formation failure due to the decomposition of the above-mentioned antistatic agent or precipitation of a gel-like substance. Furthermore, in the case of certain antistatic agents,
There is also a problem that the slipperiness of the polyamide film is reduced. An object of the present invention is to solve the problems of the conventional polyamide film described above, and to provide a laminated polyamide film which is excellent in antistatic property, and is excellent in transparency and slipperiness.

[0004]

Means for Solving the Problems The laminated polyamide film of the present invention for achieving the above object is a graft copolymer comprising a polyester containing an antistatic agent and an acrylic polymer on at least one surface of the polyamide film, or It is characterized in that an antistatic layer composed of a composition containing a graft copolymer composed of polyurethane and an acrylic polymer as a main component is laminated.

The laminated polyamide film having the above structure is a film having excellent antistatic properties, transparency and slipperiness.

The antistatic agent in the antistatic layer has 8 carbon atoms.
It can be a compound consisting of ~ 13 alkyl residues, aromatic residues and sulfonic acid sodium salt.

The laminated polyamide film having the antistatic layer having the above structure has excellent antistatic properties.

Further, the method for producing a laminated polyamide film of the present invention comprises a graft copolymer comprising an antistatic agent-containing polyester and an acrylic polymer on at least one surface of an unstretched or uniaxially stretched polyamide film or The method is characterized in that a coating solution containing a graft copolymer composed of polyurethane and an acrylic polymer as a main component is applied and then stretched.

According to the method for producing a laminated polyamide film having the above structure, a uniform antistatic layer can be easily formed to produce a laminated polyamide film having good transparency and slipperiness.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The structure of the polyamide film of the present invention and the method for producing the same will be described in detail below. First, the polyamide constituting the polyamide film used in the present invention has an amide bond as a main bonding unit component, and examples of the polyamide include polyamides obtained by polycondensation of lactams having three or more ring members, ω
Examples include polyamides obtained by polycondensation of amino acids, polyamides obtained by polycondensation of dibasic acids and diamines, and the like.

Specifically, the following monomers can be exemplified as raw materials for polyamide. Specific examples of lactams having three or more rings include ε-caprolactam, enantholactam, capryllactam, lauryl lactam and the like. Specific examples of the ω-amino acid include 6-aminocaproic acid, 7-aminoheptanoic acid, 9-aminononanoic acid,
11-aminoundecanoic acid and the like. Specific examples of dibasic acids include adipic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecandioic acid,
Dodecadionic acid, hexadecadionic acid, eicosandioic acid, 2,2,4-trimethyladipic acid, terephthalic acid, isophthalic acid, 2,6-naphthalenedicarponic acid,
Xylylenedicarboxylic acid and the like. Specific examples of diamines include ethylenediamine, trimethylenediamine, tetramethylenediamine, hexamethylenediamine, pentamethylenediamine, undecamethylenediamine, 2,
2,4 (or 2,4,4) -trimethylhexamethylenediamine, cyclohexanediamine, bis- (4,4 ′
-Aminocyclohexyl) methane, meta-xylylenediamine and the like.

Further, a polymer obtained by polycondensing these,
Or, as the copolymer thereof, nylon 6, nylon 7, nylon 11, nylon 12, nylon 6.6,
Nylon 6.9, Nylon 6.11, Nylon 6.1
2, Nylon 6 ・ T, Nylon 6 ・ I, Nylon MXD
6, nylon 6/6 ・ 6, nylon 6/12, nylon 6/6 ・ T, nylon 6/6 ・ I, nylon 6 / MXD
6 etc. are illustrated.

The polyamide film used in the present invention contains the above polyamide as a main component, and as long as its purpose and performance are not impaired, known additives such as an antioxidant, a weather resistance improver, an antigelling agent and a lubricant are used. , Antiblocking agent,
It may contain a pigment, an antistatic agent, a surfactant and the like.

The polyamide film which is a constituent of the present invention can be produced by molding polyamide into a film by a known method such as T-die method or inflation method. This polyamide film may be a single-layer film or a multilayer film by a co-extrusion method or the like.

The graft copolymer composed of polyester and an acrylic polymer and the graft copolymer composed of polyurethane and an acrylic polymer used in the present invention will be described, but the invention is not limited thereto.

In the description of the present specification, the "graft copolymer" means a copolymer in which a trunk polymer main chain is bound with a branch polymer made of a polymer different from the main chain. , "Acrylic monomer" refers to an acrylic acid derivative or a methacrylic acid derivative, and "acrylic polymer" refers to a homopolymer or a copolymer containing at least an acrylic acid derivative or a methacrylic acid derivative as a monomer component.

(Regarding Graft Polymer Composed of Polyester and Acrylic Polymer)

First, the details of the polyester used in the present invention will be described. The polyester used in the present invention is a substantially linear polymer produced from a polybasic acid or an ester-forming derivative thereof and a polyol or an ester-forming derivative thereof.

Specific examples of the polybasic acid include terephthalic acid,
Aromatic dicarboxylic acids such as isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, biphenyldicarboxylic acid and 5-sodium sulfoisophthalic acid; aliphatic dicarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid and dimer acid Acids; alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, and 1,2-cyclohexanedicarboxylic acid, and acid anhydrides thereof.

For graft polymerization, it is preferable to use a dicarboxylic acid having an unsaturated double bond in the molecule in combination. Examples of such dicarboxylic acid include fumaric acid, maleic acid, maleic anhydride, itaconic acid, Examples include α, β-unsaturated dicarboxylic acids such as citraconic acid; 2,5-norbornanedicarboxylic acid (anhydride) and unsaturated bond-containing alicyclic dicarboxylic acids such as tetrahydrophthalic anhydride. Of these, fumaric acid, maleic acid, 2,5-norbornanedicarboxylic acid, endo-bicyclo- (2,2,1) -5-heptene-2,3- are preferable.
A dicarboxylic acid is mentioned.

These dicarboxylic acids having a radical-polymerizable double bond are preferably used in the range of 0.5 to 10 mol% based on the total acid component of the raw material for polyester.
If the amount is less than mol%, the radical graft polymerization on the polyester does not proceed efficiently, and when the graft polymerization is carried out in an aqueous medium, the dispersed particle system becomes large and the stability may be deteriorated. However, if it is used in excess of 10 mol%, the viscosity rises abruptly at the latter stage of the grafting reaction, which hinders the progress of the uniform reaction, which is not preferred. A more preferred range of the dicarboxylic acid containing a double bond is 2 to 7 mol%, most preferably 3 to 6 mol% of the total acid components.

On the other hand, specific examples of the polyol include ethylene glycol, 1,2-propanediol and 1,3-
Propanediol, 1,4-butanediol, 1,5-
Pentanediol, neopentyl glycol, 1,6-
Aliphatic glycols having 2 to 10 carbon atoms such as hexanediol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, 2-ethyl-2-butylpropanediol; 1,4-cyclohexanedimethanol Alicyclic glycols having 6 to 12 carbon atoms, such as diethylene glycol, triethylene glycol, dipropylene glycol, and the like, or obtained by adding one to several moles of ethylene (or propylene) oxide to two phenolic hydroxyl groups of bisphenols. Glycols (for example, 2,2-
And ether-containing glycols such as bis (4-hydroxyethoxyphenyl) propane. Further, polyethylene glycol, polypropylene glycol, polytetramethylene glycol and the like can be partially used in combination. Furthermore, when a glycol having a polymerizable unsaturated bond such as an allyl ether group is used, a polymerizable unsaturated group can be introduced into the polyester.

In the polyester used in the present invention, it is possible to copolymerize a polycarboxylic acid or a polyol having a functionality of 3 or more. As the usable polycarboxylic acid having a functionality of 3 or more, (anhydrous) trimellitic acid is used. , (Anhydrous) pyromellitic acid, (anhydrous) benzophenone tetracarboxylic acid,
Trimesic acid, ethylene glycol bis (anhydrotrimellitate), glycerol tris (anhydrotrimellitate) and the like are used. Further, as the trifunctional or higher functional polyol, glycerin, trimethylolethane,
Trimethylolpropane, pentaerythritol, etc. are used. It is recommended that the trifunctional or higher polycarboxylic acid or polyol is contained in an amount of 5 mol% or less, preferably 3 mol% or less based on the total acid component or the total glycol component. The polyester used in the present invention can be produced by a known transesterification method, a direct esterification method, or the like using the acid component and the glycol component exemplified above. In the present invention, such a polyester can be used as it is. Here, a method for producing a graft copolymer will be described below.

Details of the acrylic monomer used in the present invention will be described. As the acrylic monomer serving as a constituent component of the acrylic polymer to be grafted with the polyester, for example, an ester portion is a methyl group, an ethyl group,
non-functional (meth) acrylates such as n- (or i-) propyl group, n- (or t-) butyl group, 2-ethylhexyl group, cyclohexyl group, phenyl group, benzyl group, phenylethyl group; Hydroxyl group-containing (meth) acrylates such as hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate; epoxy group-containing acrylates such as glycidyl (meth) acrylate; carboxyl group-containing monomers such as acrylic acid and methacrylic acid; (Sodium salt, potassium salt, ammonium salt, etc.); (meth) acrylamide, N-methyl (meth) acrylamide, N
Amide group-containing monomers such as -methylol (meth) acrylamide, N, N-dimethylolacrylamide, N-methoxy (meth) acrylamide, and N-phenylacrylamide; and one or more kinds can be used. .

As long as it is a small amount, other copolymerizable monomers may be used in combination, and examples of such copolymerizable monomers include epoxy group-containing monomers such as allyl glycidyl ether; styrene sulfonic acid and vinyl sulfonic acid. Sulfonic acid group-containing monomers and salts thereof such as; crotonic acid, (anhydrous) itaconic acid, (anhydrous) maleic acid, fumaric acid and its salts; monoesters of unsaturated dicarboxylic acids (itaconic acid, maleic acid, fumaric acid, etc.) ; Vinyl isocyanate, allyl isocyanate, styrene, α-
Examples thereof include methylstyrene, t-butylstyrene, vinyltoluene, vinylmethylether, vinyltrialkoxysilane, (meth) acrylonitrile, vinylidene chloride, vinyl acetate, and vinyl chloride. You can use it selectively.

The method for producing a graft copolymer composed of polyester and an acrylic polymer (hereinafter abbreviated as polyester-acrylic graft copolymer) is as follows:
The following methods are exemplified, but the present invention is not limited to these methods.

(1) A method in which a reaction initiation point of radical polymerization, cationic polymerization or anionic polymerization is generated in polyester, and a monomer containing at least an acrylic monomer is graft-polymerized thereto. For example, a radical polymerization method in which radicals are generated on polyester molecules by light, heat or radiation, and then a graft polymerization of a monomer containing at least an acrylic monomer, AlC
l ₃ , a cation is generated on the polyester molecule using a catalyst such as TiCl ₄ , and then a cation polymerization method in which a monomer containing an acrylic monomer is graft-polymerized, or on the polyester molecule using metal sodium, metal lithium, or the like. An anion polymerization method of generating an anion and then graft-polymerizing a monomer containing an acrylic monomer is employed. According to this method, a graft polymer in which the polyester is a trunk polymer and the acrylic polymer is a branch polymer is obtained.

(2) A method in which a polymerizable unsaturated bond is introduced into the main chain of the polyester, main chain terminals or side chains, and a monomer containing at least an acrylic monomer is graft-polymerized thereto. Also in this method, a graft polymer in which the polyester is the trunk polymer and the acrylic polymer is the branch polymer is obtained.

As a method for preparing a polyester having a polymerizable unsaturated bond in the main chain, a dicarboxylic acid having a polymerizable unsaturated bond such as fumaric acid or maleic acid, or a glycol having an allyl ether group is used for polyester production. There is a method used at times to obtain a polyester having a polymerizable unsaturated bond by copolymerization, and as a method for preparing a polyester having a polymerizable unsaturated bond at the main chain end, a hydroxyl group at the hydroxy end of the polyester is used. There is a method in which a polymerizable monomer having a polymerizable unsaturated bond is reacted with a group capable of reacting with (for example, a carboxyl group, an acid anhydride group, an acid chloride, an epoxy group, an isocyanate group), and an unsaturated bond is added to a side chain. To introduce, polyester having carboxyl group or hydroxyl group in the side chain A polymer having a functional group reactive with these groups (groups that can react with a carboxyl group, such as an amino group and an isocyanate group are the same as those described above) and a polymerizable unsaturated bond. What is necessary is just to employ | adopt the method of making a reactive monomer react.

(3) A method of reacting a polyester having a functional group in a side chain with an acrylic polymer having a group capable of reacting with the functional group at a polymer chain end, or an acrylic polymer having a functional group in a side chain And a polyester having a group capable of reacting with the functional group at the end of the polymer chain. If the former method is adopted, a graft polymer in which the polyester is a trunk polymer and the acrylic polymer is a branch polymer is obtained, and if the latter method is employed, a graft polymer in which the acrylic polymer is a trunk polymer and the polyester is a branch polymer is obtained. Is obtained.

(4) A polyester having a functional group at the side chain and an acrylic polymer having a functional group at the terminal, or an acrylic polymer having a functional group at the side chain and a polyester having a functional group at the terminal are used as these functional groups. A method of binding with a bifunctional coupling agent having reactivity with a group.
If the former method is adopted, the polyester becomes the trunk polymer,
A graft polymer in which the acrylic polymer is a branch polymer is obtained. If the latter method is adopted, a graft polymer in which the acrylic polymer is a trunk polymer and the polyester is a branch polymer is obtained. As the functional groups of the polyester, acrylic polymer, and coupling agent used here, the functional groups described in (2) above are used in combination.

Although various patterns of graft polymerization methods have been described above, it is particularly preferable to dissolve the polyester synthesized by a known method in an aqueous organic solvent,
In this method, a radical initiator and an acrylic monomer component (preferably a mixture of two or more types) are added and reacted. Also, a part of the acrylic monomer component (10 to 90
If a carboxyl group-containing monomer (acrylic acid, methacrylic acid, etc.) is used as about (% by weight), the resulting graft polymer can be neutralized with a basic compound to be in a water-dispersed state.

The above-mentioned aqueous organic solvent is not particularly limited as long as it is a solvent for polyester and an acrylic monomer, but ketones, ethers, alcohols having a boiling point of 50 to 250 ° C. are used.

Radical initiators include benzoyl peroxide, t-butyl peroxypivalate, etc .; organic azo compounds such as 2,2'-azobisisobutyronitrile and 2,2'-azobis (2,4-dimethyl). Valeronitrile) and the like. The preferred amount of the radical initiator is at least 0.2% by weight, preferably at least 0.5% by weight, based on the monomer. It is also effective to adjust the graft chain length by adding a chain transfer agent such as octyl mercaptan or mercaptoethanol at about 5% by weight or less with respect to the acrylic monomer.

As the basic compound used for neutralization, a compound that volatilizes during the formation of a coating film or bake-curing with a curing agent is preferable, and ammonia, organic amines and the like are preferable. The basic compound has a pH value of the aqueous dispersion in the range of 5.0 to 9.0 by at least partial neutralization or complete neutralization depending on the content of the carboxyl group contained in the graft copolymerization reaction product. It is desirable to determine the amount as follows.

To prepare an aqueous dispersion, the solvent contained in the graft copolymerization reaction product is previously removed by an extruder or the like under reduced pressure to obtain a melt or solid form (pellets, powder, etc.), and then a base is prepared. Although it is also possible to adopt a method of heating and stirring by pouring it into water containing a basic compound, the most preferable is to immediately add basic compound-containing water at the time when the graft polymerization reaction is completed, and subsequently heat and stir. This is a method of continuously obtaining an aqueous dispersion (one-pot method). When the boiling point of the solvent used is 100 ° C. or lower, it is also possible to distill off part or all of the solvent used for the graft polymerization reaction.

The preferred ratio of the trunk polymer to the branch polymer in the graft polymer is 5:95 to 95: by weight.
5, more preferably 80:20 to 20:80. The preferred molecular weight of the backbone polymer is 5,000 to 200,000, and the preferred molecular weight of the branch polymer is 500 to 50,000. Next, the polyurethane graft polymer will be described. In the case of a polyurethane-based graft polymer, the polyurethane used for the above-described polyester-based graft polymer can be obtained by converting the polyester to a polyurethane. Further, since the method for producing a polyester-based graft polymer can be applied to the method for producing a graft polymer, only the polyurethane-forming reaction will be described.

(Regarding Graft Copolymer Composed of Polyurethane and Acrylic Polymer) Next, a graft copolymer composed of polyurethane and an acrylic polymer used in the present invention (hereinafter abbreviated as polyurethane-acrylic graft copolymer). ) Will be described in detail. In the case of a polyurethane-acrylic graft copolymer, it can be obtained by using the polyester used in the production of the polyester-acrylic graft copolymer described above and converting it to polyurethane. Further, since the method for producing a polyester-acrylic graft copolymer can be applied to the method for producing a graft copolymer, only the polyurethane-forming reaction will be described.

The polyurethane used in the present invention is produced from the polyester polyol (a) produced according to the above-mentioned polyester production method, the organic diisocyanate compound (b), and optionally a chain extender (c) having an active hydrogen group. The preferred molecular weight is 5,000 to 100,000, the preferred urethane bond content is 500 to 4,000 equivalent / 10 ⁶ g, and the preferred content of the polymerizable double bond is per polymer chain. The average is 1.5 to 30 pieces.

The polyester polyol (a) can be produced by using the dicarboxylic acid component and the glycol component according to the above-mentioned polyester production method, and has a hydroxyl group at both ends and a molecular weight in the range of 500 to 10,000. Is preferred. The polyester polyol is used in an amount of 60 mol% to 100 mol% of the raw material dicarboxylic acid component.
It is preferable that 79.5 mol% is an aromatic dicarboxylic acid. Desirably, it is 70 mol% to 79.5 mol%. An aliphatic polyester polyol widely used for general polyurethane resins, for example, a polyurethane using an adipate of ethylene glycol or neopentyl glycol is not sufficient in water resistance, and the obtained graft copolymer makes it possible to form a slippery layer of the outermost surface layer. If water resistance is required, it should be avoided.

As an example of water resistance, a polyurethane using ethylene glycol or neopentyl glycol adipate has a low reduced viscosity retention rate of 20 to 30% after 20 days of warm water immersion at 70 ° C., but the same. Polyurethane using glycol terephthalate or isophthalate has a high reduced viscosity retention rate of 80 to 90% under the same conditions. Therefore, in order to impart high water resistance to the slippery layer, it is effective to use a polyester polyol mainly composed of an aromatic dicarboxylic acid.

If necessary, a polyether polyol, a polycarbonate polyol, a polyolefin polyol and the like can be used in combination with the polyester polyol (a).

As the organic diisocyanate compound (b), hexamethylene diisocyanate, tetramethylene diisocyanate, 3,3'-dimethoxy-4,4'-biphenylene diisocyanate, p-xylylene diisocyanate, m-xylylene diisocyanate, 1,3 −
Diisocyanate methyl cyclohexane, 4,4'-diisocyanate dicyclohexane, 4,4'-diisocyanate cyclohexylmethane, isophorone diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, p-phenylene diisocyanate, diphenylmethane diisocyanate, m -Phenylene diisocyanate, 2,4-naphthalene diisocyanate, 3,3'-dimethyl-4,4'-biphenylene diisocyanate, 4,4'-diisocyanate diphenyl ether, 1,5-naphthalene diisocyanate, and the like.

Examples of the chain extender (c) having an active hydrogen group, which is used if necessary, include ethylene glycol, propylene glycol, neopentyl glycol, 2,2-diethyl-1,3-propanediol. , Glycols such as diethylene glycol, spiroglycol, and polyethylene glycol; amines such as hexamethylenediamine, propylenediamine, and hexamethylenediamine.

The polyurethane used in the present invention comprises the polyester polyol (a), the organic diisocyanate (b) and the chain extender (c) having an active hydrogen group, which is optionally used, in the active hydrogen group of {(a) + (C) active hydrogen group} /
Those obtained by reacting at a compounding ratio of 0.8 to 1.3 (equivalent ratio) with respect to the ratio of {isocyanate group of (b)} are preferable. If the ratio is out of this preferred range, the molecular weight of the polyurethane will not be sufficiently increased, and it will be difficult to obtain satisfactory coating properties as the outermost layer.

The polyurethane may be produced by a known method using the above raw material components, for example, a method of reacting in a solvent at a reaction temperature of 20 to 150 ° C. in the presence of a catalyst or without a catalyst. As the solvent used at this time, for example, methyl ethyl ketone, methyl isobutyl ketone,
Ketones such as cyclohexanone; aromatic hydrocarbons such as toluene and xylene; esters such as ethyl acetate and butyl acetate can be used. As a catalyst for accelerating the reaction, amines, organotin compounds and the like are used.

In order to increase the efficiency of the grafting reaction in the polyurethane, it is necessary to introduce a polymerizable double bond into the molecule by using a radically polymerizable monomer, and the introduction amount is one polyurethane chain. The average number is preferably 1.5 to 30, preferably 2 to 20, more preferably 3 to 10. This polymerizable double bond may be introduced, for example, by the following methods alone or in combination. Fumaric acid, itaconic acid,
An unsaturated dicarboxylic acid such as norbornene dicarboxylic acid is contained. An allyl ether group-containing glycol is contained in the polyester polyol. An allyl ether group-containing glycol is used as a chain extender. A hydroxyl group or isocyanate group of the polyurethane is reacted with a monomer having a functional group capable of reacting with these functional groups.

Next, the antistatic agent used in the present invention will be described. The antistatic agent is not particularly limited and can be arbitrarily selected from known ones. Further, it may be a low molecular type or a high molecular type, and one kind or two or more kinds may be used in combination. A particularly preferred antistatic agent for use in the present invention is a compound consisting of an alkyl residue having 8 to 13 carbon atoms, an aromatic residue and sodium sulfonate.

Here, examples of the aromatic residue include a phenyl group, a biphenyl group, a triphenyl group, a diphenyl oxide group and a naphthalene group. The number of sodium sulfonate may be one, or may be two or more. Examples thereof include sodium dodecylbenzene monosulfonate, sodium dodecylbenzene disulfonate, sodium dodecyl dioxide monosulfonate, sodium dodecyl dioxide disulfonate, and sodium dodecyl naphthalene disulfonate. The mixing ratio of the antistatic agent (A) and the graft copolymer (B) is (A) / (B) = 0.1 / 0.9 to 0.9 / 0.1 (weight ratio ) Is preferred. 0.2 / 0.8 to 0.8 / 0.2
Is more preferable. The above range is 0.1 / 0.9
If it is less than the above range, the antistatic effect is not exhibited, which is not preferable. On the other hand, if it exceeds 0.9 / 0.1, the antistatic effect is saturated and the antistatic agent is transferred to the opposite surface in contact with the laminated surface, which adversely affects the printability and laminate properties of the polyamide film. Therefore, it is not preferable. In the present invention, the method of mixing the antistatic agent and the graft copolymer may be arbitrary. For example, a method of directly mixing an aqueous solution or aqueous dispersion of an antistatic agent and an aqueous dispersion of a graft copolymer can be mentioned. The solid content concentration of the coating liquid containing the antistatic agent and the graft copolymer is usually 5 to 20.
%, But is not limited to this.

In the present invention, the antistatic layer comprising the above-mentioned composition may further contain other additives such as an antiblocking agent, an ultraviolet absorber, a lubricant and a coloring agent. Further, there is no limitation to use a means for improving the water resistance and abrasion resistance of the antistatic layer in combination with the crosslinking agent. Examples of the cross-linking agent used in the present invention include the following, but are not limited thereto.

Phenol formaldehyde resins, amino resins, polyfunctional epoxy compounds, polyfunctional isocyanate compounds or their block compounds, polyfunctional aziridine compounds, oxazoline compounds and the like.

Examples of the phenol-formaldehyde resin include phenol and various alkylphenols,
o- (m-, p-) cresol, various xylenols, p
-Tert-butylphenol, p-tert-amylphenol, 4,4'-sec-butylidenephenol, p-cyclohexylphenol, 4,4'-isopropylidenephenol, p-nonylphenol, p-octylphenol, 3-pentadecylphenol , P-
And condensates of phenolic compounds such as phenylphenol and phenyl-o-cresol with formaldehyde.

Examples of the amino resin include addition condensation products of urea, melamine, penzoguanamine and the like with formaldehyde, and alkyl ether compounds obtained by adding an alcohol having 1 to 6 carbon atoms thereto. Specifically, methoxylated methylol urea, methoxylated methylol-N, N-ethylene urea, methoxylated methylol dicyandiamide, methoxylated methylol melamine, methoxylated methylol benzoguanamine, butoxylated methylol melamine, butoxylated methylol benzoguanamine, methylolated benzoguanamine, etc. And
These may be used alone or in combination of two or more.

As the polyfunctional epoxy compound, diglycidyl ether of bisphenol A and its oligomer,
Diglycidyl ether of hydrogenated bisphenol A and its oligomers, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether,
Diglycidyl ethers such as 4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether and polyalkylene glycol diglycidyl ether; diglycidyl orthophthalate, diglycidyl isophthalate, diglycidyl terephthalate, p -Diglycidyl oxybenzoate, diglycidyl tetrahydrophthalate,
1,4-diglycidyl esters such as diglycidyl adipate and diglycidyl sebacate;
Diglycidyloxybenzene, diglycidylpropionurea; triglycidyl isocyanurate, trimellitic acid triglycidyl ester, glycerol triglycidyl ether, trimethylolpropane triglycidyl ether, bentaerythritol triglycidyl ether, triglycidyl ether of glycerol alkylene oxide adduct, etc. Triglycidyl ethers; and the like.

As the isocyanate compound, aromatic compounds,
Aliphatic diisocyanate, trivalent or higher polyisocyanate and the like can be used, and both low molecular weight and high molecular weight compounds can be used. Specifically, hexamethylene diisocyanate, tetramethylene diisocyanate, toluene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, p-xylylene diisocyanate, m-xylylene diisocyanate Isocyanates, hydrogenated xylylene diisocyanates, isophorone diisocyanates or trimers of these isocyanates; and excess amounts of these polyfunctional isocyanate compounds and, for example, ethylene glycol, propylene glycol, trimethylolpropane,
Terminals obtained by reacting low molecular active hydrogen compounds such as glycerin, sorbitol, ethylenediamine, monoethanolamine, diethanolamine, and triethanolamine, and high molecular active hydrogen compounds such as various polyester polyols, polyether polyols, and polyamides. Examples include isocyanate compounds.

It is also possible to use blocked isocyanates, and as the blocking agent, phenols such as phenol, thiophenol, methylthiophenol, cresol, xylenol, resorcinol, nitrophenol and chlorophenol; ε-caprolactam, δ
-Lactams such as butyrolactam, τ-valerolactam and β-propyllactam; oximes such as acetoxime, methylethylketoxime and cyclohexanone oxime; methanol, n- (i-, tert-) propanol, n- (i-, tert-) ) Alcohols such as butanol; Halogen-substituted alcohols such as ethylene chlorohydrin and 1,3-dichloro-2-propanol; Active compounds such as aromatic amines, imides, acetylacetone, acetoacetic acid ester, malonic acid ethyl ester , Mercaptans, imines, ureas, diaryl compounds, sodium bisulfite and the like. For blocking, the isocyanate compound and the blocking agent may be added by a known method.

The method of blending the cross-linking agent is (1) when the cross-linking agent is water-soluble, it is directly dissolved or dispersed in an aqueous dispersion of the graft polymer, and (2) the cross-linking agent is oil-soluble. In this case, there is a method of adding it to the reaction solution after the completion of the graft polymerization reaction. These methods may be appropriately selected according to the type and properties of the crosslinking agent. When compounding the crosslinking agent, it is also effective to use a curing agent and a curing accelerator together.

In order to form the antistatic layer, a method of applying the above-mentioned coating solution to the polyamide film by a known coating method such as a gravure method, a reverse method, a die method, a bar method and a dip method may be adopted.

The antistatic layer is applied or formed on an unstretched, uniaxially stretched or biaxially stretched polyamide film, or is applied on an unstretched or uniaxially stretched polyamide film.
It is effective to dry and further uniaxially stretch or biaxially stretch, and optionally heat set to form the film. When forming a coating film on the surface of a biaxially stretched polyamide film, the preferable drying or heat setting temperature after coating the coating solution is 150.
C. or higher, preferably 200.degree. C. or higher, a strong coating surface is formed under such temperature conditions, and the adhesiveness with the polyamide film is improved.

When the method of stretching after coating is used,
Although it is particularly easy to obtain a uniform surface, it is preferable to control the moisture content of the polyamide film in the range of 0.1 to 2% so that drying after application does not impair the stretchability of the coating film. . Also in this case, when the film is stretched and then heat-fixed at 200 ° C. or higher, the coating film as the slippery layer becomes stronger and the polyamide film is more firmly bonded and integrated.

The coating amount of the coating liquid for forming the antistatic layer is 0.005 to 0.5 g / m in terms of solid content after drying.
² , preferably in the range of 0.01 to 0.2 g / m ² ,
If the coating amount is insufficient, the effect expected as the antistatic layer will not be fully exhibited, and if the coating amount is too large, problems such as blocking will easily occur.

In producing the film of the present invention, surface activation treatment by a method such as corona discharge treatment, plasma treatment, ultraviolet ray irradiation treatment and fire treatment is not limited in any way. The surface treatment may be performed on either one or both of the antistatic layer surface and the opposite surface, but it is usual to perform the surface activation treatment only on the opposite surface side.

<Examples> The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited by the following examples, and is within a range applicable to the gist of the present invention. The present invention can be implemented with appropriate modifications, and all of them are included in the scope of the present invention. In the examples, simply "part" means "part by weight",
Unless otherwise specified, "%" means "% by weight".
Moreover, the measurement of the characteristic value in this specification followed the following method.

(1) Transparency Measured according to the JIS-K-6714 method.

(2) Static Friction Coefficient of Film The static friction coefficient between the antistatic layer and the opposite surface of the film is AST.
According to the MD-1894 method, the measurement was performed in an atmosphere of 50% relative humidity.

(3) Antistatic property of film According to JIS-K-6911, using an R8340 type surface resistance measuring instrument manufactured by Advantest Corporation, 23 ° C., humidity 5
The surface resistance value was measured in an environment of 0% and expressed in logarithm.

(Example 1) Polyester-acrylic graft copolymer (coating solution)
In a stainless steel autoclave equipped with a stirrer, a thermometer and a partial reflux condenser, dimethyl thylephthalate: 466 parts, dimethyl isophthalate: 466 parts, neopentyl glycol: 401 parts, ethylene glycol: 443 parts and tetra- n-butyl titanate 0.5
Two parts were charged and the transesterification reaction was carried out at 160 to 220 ° C. for 4 hours. Then, 23 parts of fumaric acid was added, and the temperature was raised from 200 ° C. to 220 ° C. over 1 hour to carry out an esterification reaction. Then, the temperature was raised to 255 ° C., and the pressure of the reaction system was gradually reduced. Then, the reaction was carried out under a reduced pressure of 0.2 mmHg for 1 hour and 30 minutes to obtain a polyester. The obtained polyester was light yellow and transparent, had a glass transition point of 60 ° C. and had a weight average molecular weight of 12,000. The composition of this polyester measured by NMR or the like was as follows.

Dicarboxylic acid component Terephthalic acid: 48 mol% Isophthalic acid: 48 mol% Fumaric acid: 4 mol% Diol component Neopentyl glycol: 50 mol% Ethylene glycol: 50 mol%

Next, in a reactor equipped with a thermometer, a reflux condenser and a constant amount dropping device, the above polyester (75 parts) was charged together with methyl ethyl ketone (56 parts) and isopropyl alcohol (19 parts), and heated and dissolved at 65 ° C. After the resin was completely dissolved, a mixture of 17.5 parts of methacrylic acid and 7.5 parts of ethyl acrylate and a solution obtained by dissolving 1.2 parts of azobisdimethyl valeronitrile in 25 parts of methyl ethyl ketone were used. The solution was dropped into the polyester solution at a rate of 0.2 cc / min, and stirring was continued at the same temperature for another 2 hours. Sampling for analysis from reaction solution (5g)
After that, 300 parts of water and 25 parts of triethylamine were added to the reaction solution, and the mixture was stirred for 1 hour to obtain an aqueous dispersion.
Thereafter, the temperature of the aqueous dispersion was raised to 100 ° C., and methyl ethyl ketone, isopropyl alcohol and an excess amount of triethylamine were distilled off. The resulting aqueous dispersion is white, B
The mold viscosity is 50 cps (25 ° C.), and the average particle size is 30
It was an aqueous dispersion in which fine particles of 0 nm were uniformly dispersed.
The weight average molecular weight of the graft polymerized portion is 10,000.
Met.

[Production of Polyamide Film and Formation of Antistatic Layer] The above aqueous dispersion, an aqueous solution of sodium dodecyldiphenyloxide disulfonate, a polyester-acrylic graft copolymer, and sodium dodecyldiphenyloxide disulfonate are weighed. 5: 5 by ratio
And a coating liquid was prepared by diluting with water so that the solid content concentration became 5%. On the other hand, nylon 6 containing 0.1% ethylenebisstearylamide and 3,500 ppm of amorphous silica having an average particle size of 2.0 μm was melt extruded from a T die and cooled on a cooling drum at 30 ° C. to obtain a thickness. 15
An unstretched polyamide film of 0 μm was obtained. This unstretched film was longitudinally stretched 3.1 times at 50 ° C. 1 obtained
The coating solution for antistatic layer was coated on one side of the axially stretched film by a rotating Myer bar and dried at 85 ° C. Then, it was stretched 3.3 times in the transverse direction at 125 ° C.
Heat setting was performed at 5 ° C. The thickness of the antistatic layer is 0.10μ
m, and the thickness of the polyamide film was 15 μm. Corona treatment was applied to the non-coding surface on which the antistatic layer was not formed, and the surface tension was set to 48 dyne / cm. The characteristics of the obtained laminated polyamide film are shown in Table 1. The laminated polyamide film obtained in this example has excellent antistatic properties, and also has good transparency and slipperiness, and is of high quality.

Comparative Example 1 A biaxially stretched polyamide film was obtained in the same manner as in Example 1 except that the antistatic layer was not provided. The characteristics of the obtained polyamide film are shown in Table 1. The film obtained in this comparative example,
The transparency was good, but the antistatic property and slipperiness were poor.

Comparative Example 2 A laminated polyamide film was obtained in the same manner as in Example 1 except that the coating liquid for forming the antistatic layer was not mixed with sodium dodecyldiphenyloxide disulfonate. The characteristics of the obtained laminated polyamide film are shown in Table 1. The laminated polyamide film obtained in this comparative example was inferior in antistatic property.

Example 2 The same method as in Example 1 except that the polyurethane-acrylic graft copolymer produced by the following method is used in place of the polyester-acrylic graft copolymer in the method of Example 1. A laminated polyamide film was obtained.

[Production of Polyester Polyol] Dimethyl terephthalate was added to a stainless steel autoclave equipped with a stirrer, a thermometer and a partial reflux condenser.
543 parts, neopentyl glycol: 458 parts, ethylene glycol: 410 parts, and tetra-n-butyl titanate: 0.52 parts were charged, and transesterification was carried out at 160 to 220 ° C. for 4 hours. Then fumaric acid:
23 parts and sebacic acid: 51 parts were added, and 200 ° C to 2
After raising the temperature to 20 ° C. and gradually reducing the pressure of the reaction system, 0.5 m
The reaction was carried out for 30 minutes under a reduced pressure of mHg to obtain a polyester polyol (A-1). The obtained polyester polyol (A-1) was pale yellow and transparent, and had a reduced viscosity of 0.3. The composition of this polyester polyol measured by NMR or the like was as follows. Dicarboxylic acid component Terephthalic acid: 56 mol% Sebacic acid: 40 mol% Fumaric acid: 4 mol% Diol component Neoventil glycol: 50 mol% Ethylene glycol: 50 mol%

[Production of Polyurethane] 100 parts of the polyester polyol (A-1) obtained by the above method was charged together with 120 parts of methyl ethyl ketone in a reactor equipped with a thermometer, a stirrer and a reflux condenser. After melting
Neopentyl glycol: 3 parts, isophorone diisocyanate: 15 parts, and dibutyltin laurate: 0.02 part were charged and reacted at 60 to 70 ° C for 6 hours. Next, the reaction system was cooled to 70 ° C. to stop the reaction. The reduced viscosity of the obtained polyurethane (B-1) was 0.56.

[Production of Graft Copolymer] In a reactor equipped with a stirrer, a thermometer, a reflux device and a metering dropping device, a solution of the polyurethane (B-1) obtained above in methyl ethyl ketone (solid content concentration: 50% ): 150 parts, and iropropyl alcohol: 15 parts, and the temperature was raised to 65 ° C., and then a mixture of methacrylic acid: 17.5 parts and ethyl acrylate: 7.5 parts, and azobisdimethylvaleronitrile: 1. 2 copies 2
A solution prepared by dissolving 5 parts of methyl ethyl ketone and 5 parts of isopropyl alcohol in a mixed solution was dropped into the polyurethane solution at a rate of 0.2 ml / min, and stirring was continued for another 2 hours at the same temperature. After sampling (5 g) for analysis from the reaction solution, 300 parts of water and 25 parts of triethylamine were added to the reaction solution, and the mixture was stirred for 1 hour to obtain an aqueous dispersion. Then, the temperature of the dispersion was raised to 100 ° C., and methyl ethyl ketone, isopropyl alcohol and excess triethylamine were removed by distillation. The resulting aqueous dispersion (C-1) was white and had a B-type viscosity of 50 cps (2
It was 5 ° C.), and it was a dispersion liquid in which fine particles having an average particle diameter of 300 μm were uniformly dispersed. The characteristics of the obtained laminated polyamide film are shown in Table 1. The laminated polyamide film obtained in this example was also of high quality as the film of Example 1.

Comparative Example 3 A laminated polyamide film was obtained in the same manner as in Example 1 except that the coating solution for the antistatic layer was not mixed with sodium dodecyldiphenyloxide disulfonate. The characteristics of the obtained laminated polyamide film are shown in Table 1. The antistatic property of the laminated polyamide film obtained in this Comparative Example was inferior to that of the laminated polyamide film of Example.

(Example 3) In the method of Example 1, sodium dodecyl benzene sulfonate was used instead of sodium dodecyl diphenyl oxide disulfonate in the coating solution for the antistatic layer, and the compounding ratio was 6: 4, and the charging was performed. Example 1 except that the thickness of the prevention layer was 0.05 μm
A laminated polyamide film was obtained by the same method as described above. The characteristics of the obtained laminated polyamide film are shown in Table 1. The film obtained in this example was also of high quality.

Example 4 In the method of Example 3, the coating liquid for the antistatic layer was replaced with the graft copolymer consisting of polyester and acrylic polymer, and the polyurethane and acrylic polymer used in Example 2 were used. A laminated polyamide film was obtained in the same manner as in Example 2, except that the following graft copolymer was used. The characteristics of the obtained laminated polyamide film are shown in Table 1. The film obtained in this example was also of high quality.

[0080]

[Table 1]

[0081]

EFFECT OF THE INVENTION The laminated polyamide film of the invention according to claim 1 is excellent in antistatic property, and is excellent in transparency and slipperiness. The laminated polyamide film of the invention according to claim 2 is particularly excellent in stable antistatic property. According to the method for producing a laminated polyamide film of the third aspect of the present invention, it is possible to easily obtain a laminated polyamide film having a uniform antistatic layer and having transparency and slipperiness.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical display location B29L 9:00 (72) Inventor Tsutomu Isaka 2-8 Dojimahama, Kita-ku, Osaka Toyobo Co., Ltd. Company head office

Claims (3)

[Claims] 1. A composition containing, as a main component, a graft copolymer composed of polyester containing an antistatic agent and an acrylic polymer or a graft copolymer composed of polyurethane and an acrylic polymer on at least one surface of a polyamide film. A laminated polyamide film, comprising an antistatic layer composed of: 2. The laminated polyamide film according to claim 1, wherein the antistatic agent is a compound consisting of an alkyl residue having 8 to 13 carbon atoms, an aromatic residue and sodium sulfonate. 3. A graft copolymer comprising a polyester containing an antistatic agent and an acrylic polymer or a graft copolymer comprising a polyurethane and an acrylic polymer on at least one surface of an unstretched or uniaxially stretched polyamide film. After applying the coating liquid containing as a main component,
A method for producing a laminated polyamide film, which comprises stretching.