JPH09248886A - Laminated polyamide film and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the easy sliding properties under a high humidity atmosphere by laminating an easy sliding layer composed of a blend of water-soluble or water-dispersion resin with a polyolefin wax at least on one face of a base layer composed of a polyamide film. SOLUTION: An easy sliding layer composed of a blend of water-soluble or water-dispersion resin with a polyolefin wax is laminated at least on one face of a base layer composed of a polyamide film. The water-soluble or water- dispersion resin is a graft copolymer resin composed of a polyester and an acrylic polymer or a graft copolymer resin composed of a polyurethane and an acrylic polymer. In other words, a coating fluid prepared by blending a polyolefin wax with a water solution of a water-soluble resin or a water- dispersion fluid of a water-dispersion resin is applied at least on one face of a non-polyamide film to manufacture a laminated polyamide film.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a laminated polyamide film excellent in slipperiness, particularly slipperiness under high humidity, and a method for producing the same.

[0002]

2. Description of the Related Art Polyamide films are generally excellent in mechanical properties, optical properties, thermal properties, gas barrier properties, toughness, pinhole resistance, bending resistance, etc. and are widely used mainly in the food packaging field. ing. However, the conventional polyamide film has a high hygroscopic property due to the peculiarity of the polyamide itself, and the slipperiness of the film decreases as the atmospheric humidity increases, so that the workability in the film processing step is deteriorated.

The laminate using the above-mentioned polyamide film also has the drawback that the characteristics of each polyamide film are reflected as they are and the slipperiness under high humidity deteriorates. Further, in recent years, there is a strong demand for a laminated film having low-temperature heat sealability and excellent impact resistance,
In this field, a laminated film of a biaxially stretched polyamide film and a linear low density polyethylene (LLDPE) is widely used. However, the laminated film is LLD
Since the PE is soft, blocking is likely to occur, and there is a problem that the laminated film causes a blocking phenomenon during laminating or bag making. Therefore, at the time of laminating or bag making, a measure is taken to avoid the above problem by shaking powder such as starch. However, this method has problems such as not only contaminating the periphery of the processing apparatus but also significantly deteriorating the appearance of food packaging, and improvement thereof has been desired. Further, although this problem has been investigated as a method by improving the anti-blocking property of the LLDPE layer,
It can also be improved by improving the slipperiness of the polyamide film. However, the current situation is that we are still not satisfied.

Conventionally, in order to improve the above-mentioned problems,
As a method for reducing the frictional force on the friction surface between films or a material in contact with the film, a method of containing inorganic or organic fine particles inert to polyamide, thermoplastic polymer fine particles incompatible with polyamide, etc. Has been used.

[0005]

However, the polyamide film obtained by such a method shows good slipperiness in a normal, low-humidity atmosphere, but satisfies the market demand for use in a high-humidity atmosphere. It was in a difficult situation. 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 excellent in slipperiness, particularly slipperiness in a high humidity atmosphere.

[0006]

In order to achieve the above object, the laminated polyamide film of the present invention comprises a mixture of a water-soluble or water-dispersible resin and a polyolefin wax on at least one surface of a base layer made of a polyamide film. It is characterized in that the slippery layer is laminated. The laminated polyamide film of the present invention having the above constitution is excellent in slipperiness, particularly slipperiness in a high humidity atmosphere.

Further, the laminated polyamide film of the present invention is a water-soluble or water-dispersible resin which is a graft copolymer resin composed of polyester and an acrylic polymer or a graft copolymer resin composed of polyurethane and an acrylic polymer. It is characterized by The laminated polyamide film of the present invention having the above-mentioned constitution is excellent in a high degree of slipperiness, particularly in a high humidity atmosphere.

Further, the method for producing a laminated polyamide film of the present invention comprises applying an aqueous solution of a water-soluble or water-dispersible resin or a coating solution containing a polyolefin wax to an aqueous dispersion on at least one surface of an unstretched polyamide film. , Biaxially stretched. According to the method for producing a laminated polyamide film of the present invention having the above-mentioned constitution, easily, a laminated polyamide film having a uniform slippery layer and excellent in slipperiness particularly in a high-humidity atmosphere is obtained. It can be manufactured.

Further, the method for producing a laminated polyamide film of the present invention comprises the steps of applying an aqueous solution of a water-soluble or water-dispersible resin or a coating solution prepared by blending a polyolefin wax into an aqueous dispersion on at least one side of a uniaxially stretched polyamide film. The uniaxially stretched polyamide film is stretched in a direction perpendicular to the stretching direction. According to the method for producing a laminated polyamide film of the present invention having the above-mentioned structure, easily and easily slippery with a uniform slippery layer,
In particular, it is possible to produce a laminated polyamide film having excellent slipperiness in a high humidity atmosphere.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the laminated polyamide film of the present invention will be specifically described below. As the polyamide used in the laminated polyamide film of the present invention, typically, nylon 6 having ε-caprolactam as a main raw material or nylon 6.6 having hexamethylenediamine and adipic acid as main raw materials can be mentioned. Other polyamides include lactams having three or more membered rings, ω-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. As the lactam, in addition to the above-mentioned ε-caprolactam, enanthlactam, capryllactam, lauryllactam and the like.
Examples of ω-amino acids include 6-aminocaproic acid, 7-aminoheptanoic acid, 9-aminononanoic acid and 11-aminoundecanoic acid. As the dibasic acid, in addition to the adipic acid described above, glutaric acid, pomeric acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecadioic acid, hexadecadioic acid, eicosandioic acid, eicosadienediene diacid. Onic acid, 2,2,4-trimethyladipic acid, terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, xylylenedicarboxylic acid and the like. As diamines, in addition to hexamethylenediamine described above, ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, undecamethylenediamine, 2,2,4 (or 2,4,4)-
Trimethylhexamethylenediamine, cyclohexanediamine, bis- (4,4'-aminocyclohexyl) methane, metaxylylenediamine and the like. Polyamide is a polymer obtained by polycondensing the above-exemplified monomers or a copolymer thereof, for example, nylon 6, 7, 1
1, 12, 6 ・ 6, 6 ・ 9, 6 ・ 11, 6 ・ 12, 6 ・
T, 6 · I, MXD · 6, 6/6 · 6, 6/12, 6 /
6 · T, 6/6 · I, 6 / MXD · 6 and the like.

Various additives may be added to the above polyamide as long as the object and performance of the present invention are not impaired. For example, an antioxidant, a light fastness agent, an antigelling agent, a lubricant, an antiblocking agent, a pigment, an antistatic agent, a surfactant and the like can be added.

The polyamide film used in the present invention can be formed using the above-mentioned polyamide by a known film forming method. As a film forming method, a T-die method, an inflation method or the like can be applied, and it may be a non-stretched film, a uniaxially stretched film, or a simultaneous or sequential biaxially stretched film. . The polyamide film used in the present invention may be a single layer film or a multilayer film obtained by a coextrusion method or the like.

Examples of the water-soluble or water-dispersible resin used in the present invention include polyester resins, polyurethane resins, polyacrylic resins and polyamide resins. As these resins, existing commercially available resins may be used or newly developed products may be used. Further, one kind may be used, or two or more kinds may be mixed and used. From the viewpoint that a high degree of slipperiness can be expressed on the film surface, a graft copolymer resin composed of polyester and an acrylic polymer among polyester resins, and a polyurethane and an acrylic polymer among polyurethane resins It is a preferred embodiment to use a graft copolymer resin. The solvent and dispersion medium for forming the aqueous solution or the aqueous dispersion may be 100% water or a mixture with an organic solvent, particularly a mixture with 50% or less of an organic solvent.

Hereinafter, 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 in detail, but the invention is not limited thereto. In the description in the present specification, the “graft copolymer” refers to a copolymer in which a trunk polymer main chain is bound with a branch polymer made of a polymer different from the main chain, and also “acrylic monomer”. The "" means an acrylic acid derivative or a methacrylic acid derivative, and the "acrylic polymer" means a homopolymer or a copolymer containing at least an acrylic acid derivative or a methacrylic acid derivative as a monomer component.

(Regarding Graft Copolymer Composed of Polyester and Acrylic Polymer)

First, 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 its ester-forming derivative and a polyol or its ester-forming derivative.

Specific examples of polybasic acids include terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, biphenyldicarboxylic acid, aromatic dicarboxylic acids such as 5-sodiumsulfoisophthalic acid, succinic acid,
Aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, dimer acid, 1,4-
Examples thereof include alicyclic dicarboxylic acids such as 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, and itaconic acid. Α, β-unsaturated dicarboxylic acids such as citraconic acid, 2,5-
Examples thereof include unsaturated bond-containing alicyclic dicarboxylic acids such as norbornane dicarboxylic acid (anhydride) and tetrahydrophthalic anhydride. Of these, fumaric acid, maleic acid and 2,5-norbornanedicarboxylic acid, endo-bicyclo- (2,2,1) -5-heptene-2, are preferred.
It is a 3-dicarboxylic acid. These dicarboxylic acids having a radical-polymerizable double bond are preferably used in the range of 0.5 to 10 mol% in the total acid component of the raw material for polyester, and when the amount is less than 0.5 mol%, it is relative to the polyester. The radical graft polymerization does not proceed efficiently, and when the graft polymerization is carried out in an aqueous medium, the dispersed particle size may become large and the stability may deteriorate. If it is used in excess of 10 mol%, the viscosity will increase sharply in the latter stage of the grafting reaction,
It is not preferable because it hinders the progress of the homogeneous reaction. The more preferable range of the double bond-containing dicarboxylic acid is 2 to all the acid components.
It is 7 mol%, most preferably 3 to 6 mol%.

On the other hand, specific examples of the polyol include ethylene glycol, 1,2-propylene glycol, 1,
3-propanediol, 1,4-butanediol, 1,
5-pentanediol, neopentyl glycol, 1,
6-hexanediol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, 2-ethyl-2-
Aliphatic glycols having 2 to 10 carbon atoms such as butylpropanediol, alicyclic glycols having 6 to 12 carbon atoms such as 1,4-cyclohexanedimethanol, diethylene glycol, triethylene glycol, dipropylene glycol, and bisphenol Glycols obtained by adding 1 to several moles of ethylene (or propylene) oxide to the two phenolic hydroxyl groups of the group (for example,
2,2-bis (4-hydroxyethoxyphenyl) propane and the like) and ether bond-containing glycols. In addition, 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. As the trifunctional or higher functional polyol, glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, etc. are used. It is recommended that the content of trifunctional or higher polycarboxylic acid or polyol is 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 is
It can be produced by a known transesterification method, direct esterification method or the like using the above-exemplified acid component and glycol component. 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 and phenylethyl group, Hydroxyl group-containing (meth) acrylate such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate, epoxy group-containing acrylate such as glycidyl (meth) acrylate, carboxyl group-containing monomer such as acrylic acid and methacrylic acid And salts thereof (sodium salt, potassium salt, ammonium salt, etc.),
(Meth) acrylamide, N-methyl (meth) acrylamide, N-methylol (meth) acrylamide, N,
Examples thereof include amide group-containing monomers such as N-dimethylol acrylamide, N-methoxy (meth) acrylamide, and -phenyl acrylamide, and one or more of these can be used.

Other copolymerizable monomers may be used in combination as long as the amount is small, 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, 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-methylstyrene, t-butylstyrene, vinyltoluene, vinylmethyl ether, vinyltrialkoxysilane, (meth) acrylonitrile, vinylden chloride, vinyl acetate, vinyl chloride and the like. Yes, one or two of these It is possible to use the above.

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 the production 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 monomer containing at least an acrylic monomer is graft-polymerized, AlCl
3. Cationic polymerization method in which a cation is generated on the polyester molecule by using a catalyst such as TiCl4, and then a monomer containing an acrylic monomer is graft-polymerized, or anion is generated on the polyester molecule by using metallic sodium or metallic lithium. Then, an anionic polymerization method in which a monomer containing an acrylic monomer is graft-polymerized is adopted. According to these methods, a graft copolymer 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. This method also gives a graft copolymer in which the polyester is the trunk polymer and the acrylic polymer is the branch polymer. As a method for producing 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 during polyester production. There is a method of obtaining a polyester having a polymerizable unsaturated bond by copolymerization, and as a method of producing a polyester having a polymerizable unsaturated bond at the main chain terminal, a hydroxyl group can be reacted with a hydroxyl group at the hydroxy terminal of the polyester. There is a method of reacting a polymerizable monomer having a polymerizable unsaturated bond with a group (for example, a carboxyl group, an acid anhydride, an acid chloride, an epoxy group, an isocyanate group, etc.), and to introduce an unsaturated bond into a side chain, Polyesters having a carboxyl group or a hydroxyl group in the side chain part of these groups A polymerizable monomer having a reactive functional group (a group capable of reacting with a carboxyl group, an amino group, an isocyanate group, etc., and a group capable of reacting with a hydroxyl group is the same as above) and a polymerizable unsaturated bond are reacted. The method of letting it be adopted.

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

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

Although various patterns of graft polymerization methods have been described above, it is particularly preferable to dissolve the polyester produced 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. In addition, a part of the acrylic monomer component (10 to 9
When a carboxyl group-containing monomer (acrylic acid, methacrylic acid, etc.) is used as about 0% by weight), the resulting graft copolymer can be neutralized with a basic compound to form an aqueous dispersion state.

The above-mentioned aqueous organic solvent is not particularly limited as long as it is a solvent of polyester and an acrylic monomer, but ketones and ethers having a boiling point of 50 to 250 ° C.,
Alcohols 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 the neutralization, a compound which volatilizes at the time of forming a coating film or baking hardening by adding a curing agent is desirable, and ammonia, organic amines and the like are preferable. The basic compound has a pH value of the aqueous dispersion of 5.0 to 9.0 depending on the content of the carboxyl group contained in the graft copolymerization reaction product by at least partial neutralization or complete neutralization. It is desirable to determine the amount so that

The preferred ratio of the trunk polymer to the branch polymer in the graft copolymer 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.

To prepare an aqueous solution or an aqueous dispersion, the solvent contained in the graft copolymerization reaction product is removed in advance by an extruder or the like under reduced pressure to obtain a melt or solid form (pellets, powder, etc.). The method of throwing in water containing a basic compound and heating / stirring can be adopted, but the most preferable is to add water containing a basic compound immediately after completion of the graft polymerization reaction, and subsequently heat the mixture. -A method of continuously stirring to obtain an aqueous dispersion (one-pot method). The boiling point of the solvent used is 10
When the temperature is 0 ° C. or lower, part or all of the solvent used in the graft polymerization reaction can be distilled off.

(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. Since the method for producing the graft copolymer can be the same as the method for producing the polyester-acrylic graft copolymer, only the polyurethane-forming reaction will be described.

The polyurethane used in the present invention can be produced from the polyester polyol (a), the organic diisocyanate compound (b) and, if necessary, the chain extender (c) having an active hydrogen group, and its preferable molecular weight is 5,000 to 100,000, a preferable urethane bond content is 500 to 4,000 equivalent / 10 6 g, and a preferable content of the polymerizable double bond is 1.
It is 5 to 30 pieces.

The above polyester polyol (a) is
It can be produced by using the dicarboxylic acid component and the glycol component according to the above-mentioned method for producing polyester, and those having hydroxyl groups at both ends and a molecular weight of 500 to 10,000 are preferable. 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. It is preferably 70 mol% to 79.5 mol%.
An aliphatic polyester polyol that is widely used for general polyurethane resins, for example, a polyurethane using an adipate of ethylene glycol or neopentyl glycol does not have sufficient water resistance, and a slipping layer that is the outermost surface layer of the resulting graft copolymer. If water resistance is required, it should be avoided.

As an example of water resistance, the retention of reduced viscosity of polyurethane using adipate of ethylene glycol or neopentyl glycol after being immersed in warm water at 70 ° C. for 20 days is as low as 20 to 30%. Polyurethane using glycol terephthalate or isophthalate has a high reduced viscosity retention ratio 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, etc. may be used in combination with the polyester polyol (a).

The above organic diisocyanate compound (b)
As, hexamethylene diisocyanate, tetramethylene diisocyanate, 3,3′-dimethoxy-4,
4'-biphenylene diisocyanate, p-xylylene diisocyanate, m-xylylene diisocyanate,
1,3-diisocyanate methylcyclohexane, 4,
4'-diisocyanate dicyclohexane, 4,4'-
Diisocyanate cyclohexylmethane, isophorone diisocyanate, 2,4-tolylene diisocyanate,
2,6-tolylene diisocyanate, p-phenylene diisocyanate, diphenylmethane diisocyanate,
Examples thereof include m-phenylene diisocyanate, 2,4-naphthalene diisocyanate, 3,3 ′ dimethyl-4,4′-biphenylene diisocyanate, 4,4′-diisocyanate diphenyl ether, and 1,5-naphthalene diisocyanate.

Examples of the chain extender (c) having an active hydrogen group, which is optionally used, include ethylene glycol, propylene glycol, neopentyl glycol, 2,2-diethyl-1,3-propanediol. ,
Examples thereof include 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 content is out of this range, the molecular weight of polyurethane will not be sufficiently increased, and it will be difficult to obtain satisfactory coating properties as an easily slipping layer.

The polyurethane may be produced by a known method using the above-mentioned raw material components, for example, a method of reacting in a solvent at a reaction temperature of 20 to 150 ° C. in the presence or absence of 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, and 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 graft reaction in the polyurethane, it is necessary to introduce a polymerizable double bond into the molecule by using a radical polymerizable monomer, and the amount of introduction is one polyurethane chain. The average number is preferably 1.5 to 30, preferably 2 to 20, and more preferably 3 to 10.

The introduction of the polymerizable double bond may be carried out 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. The hydroxyl group or isocyanate group of polyurethane is reacted with a monomer having a functional group capable of reacting with these functional groups.

Next, the polyolefin wax used in the present invention will be described. The polyolefin wax used in the present invention is not particularly limited as long as it is a wax of polyolefin resin, but a wax of polyethylene or polypropylene is preferable in terms of slipperiness.
The method for producing the polyolefin wax is not limited, and it may be produced by a known method, for example, by the telomerization method or by a thermal decomposition method of polyolefin. Further, it may be a modified product having a functional group introduced by oxidation treatment or the like. Particularly, an aqueous dispersion can be preferably used. The degree of polymerization of polyolefin wax is usually about 5
0 to about 400, and the melting point is about 100 to 15
The temperature is about 0 ° C., but is not limited to this.

The compounding ratio of the water-soluble or water-dispersible resin (A) and the polyolefin wax (B) is preferably (B) / (A) = 0.005-0.3 (weight ratio). . In particular, it is more preferably 0.02 to 0.2. If the above range is less than 0.005, the slipping effect is not exhibited, which is not preferable. On the other hand, if it exceeds 0.3, the slippery effect is saturated and the polyolefin wax is transferred to the opposite surface in contact with the laminated surface, which adversely affects the printability and laminating characteristics of the polyamide film, which is not preferable.

The method of incorporating the polyolefin wax into the aqueous solution or dispersion of the water-soluble or water-dispersible resin is arbitrary, and for example, it may be a method of self-dissolving or dispersing, or a method of emulsifying agent such as a surfactant. A method of dispersing them by combination may be used. Further, the method used in the above-mentioned method for producing the polyester-acrylic graft copolymer or the polyurethane-acrylic graft copolymer can be used as it is. If necessary, a small amount of a water-soluble organic solvent such as a lower alcohol may be used together during the water dispersion. The solid content concentration of the coating solution in which the polyolefin wax is mixed with the aqueous solution or the aqueous dispersion of the water-soluble or water-dispersible resin is usually about 5 to 20%, but is not limited thereto. In the present invention, the slippery layer made of the above-mentioned compound further comprises an antiblocking agent, U
Other additives such as V absorber and antistatic agent may be contained. Further, there is no limitation to use a means for improving the water resistance and abrasion resistance of the slippery layer in combination with a crosslinking agent.

In order to form the slippery layer, the above-mentioned coating solution may be applied 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. .

The slippery 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 preferred drying or heat setting temperature after coating the coating solution is 150 ° C.
As described above, the temperature is preferably 200 ° C. or higher, and a strong coating film is formed under such temperature conditions, and the adhesiveness with the polyamide film becomes good.

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 slippery 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 of the slippery layer is not sufficiently exhibited, and if the coating amount is too large, problems such as blocking tend to occur.

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

[0054]

The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to the following examples, and is appropriately modified within a range compatible with the gist of the present invention. It is also possible to add and implement, and all of them are included in the technical scope of the present invention. In the examples, simply "part" means "part by weight" and "%"
Unless otherwise specified, "% by weight" means "% by weight". The characteristic values were measured according to the following method. [Surface tension] It was measured according to JIS-K-6768. [Static Friction Coefficient of Film] The coefficient of static friction between the easily slipping layers of the film and the surface opposite to the easily slipping layer is ASTM-D-1.
According to Method 894, the measurement was performed in an atmosphere of relative humidity of 50% or 65%.

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 terephthalate: 466 parts, dimethyl isophthalate: 466 parts,
Neopentyl glycol: 401 parts, ethylene glycol: 443 parts and tetra-n-butyl titanate:
0.52 parts were charged and the transesterification reaction was carried out at 160 to 220 ° C. for 4 hours. Then fumaric acid: 23
Parts were added and the temperature was raised from 200 ° C. to 220 ° C. over 1 hour to carry out an esterification reaction. Next, the temperature was raised to 255 ° C., the pressure of the reaction system was gradually reduced, and then the reaction was performed under a reduced pressure of 0.2 mmHg for 1 hour and 30 minutes to obtain a polyester. The obtained polyester is light yellow transparent and has a glass transition temperature of 60.
C., the weight average molecular weight was 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%

Then, in a reactor equipped with a thermometer, a reflux condenser and a constant amount dropping device, 75 parts of the above polyester was charged together with 56 parts of methyl ethyl ketone and 19 parts of isopropyl alcohol, and heated and dissolved at 65 ° C. After the resin was completely dissolved, a mixture of methacrylic acid: 17.5 parts and ethyl acrylate: 7.5 parts and a solution of azobisdimethylvaleronitrile: 1.2 parts in 25 parts of methyl ethyl ketone were added to It was added dropwise to the above polyester solution at a rate of 0.2 ml / min, and stirring was continued for another 2 hours at the same temperature. After sampling for analysis (5 g) from the reaction solution, 300 parts of water and 25 parts of triethylamine were added to the reaction solution and stirred for 1 hour to obtain an aqueous dispersion. Then, the temperature of the aqueous dispersion was raised to 100 ° C., and methyl ethyl ketone, isopropyl alcohol and excess 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 was 10,000.

(Production of Polyamide Film and Formation of Sliding Layer) The above aqueous dispersion and an aqueous dispersion of polyethylene wax (Polylon 393, manufactured by Chukyo Yushi Co., Ltd.) were used.
A coating solution was prepared by diluting the polyester-acrylic graft copolymer and polyethylene wax in a weight ratio of 9: 1 with water so that the solid content concentration was 5%. On the other hand, Nylon 6 containing ethylenebisstearylamide: 0.1% and 3500 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 of A stretched polyamide film was obtained. This unstretched film was longitudinally stretched 3.1 times at 50 ° C. One side of the obtained uniaxially stretched film was coated with the above coating solution for a slippery layer by a rotating Mayer bar and dried at 85 ° C. Then, the film was stretched 3.3 times in the transverse direction at 125 ° C and heat-set at 215 ° C. The slippery layer has a thickness of 0.05 μm, and the polyamide film has a thickness of 1
It was 5 μm. Corona treatment is applied to the non-coated surface where the slippery layer is not formed, and the surface tension is 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 was excellent in slipperiness even under high humidity. In addition, a laminate of the laminated polyamide film obtained in this example and LLDPE having excellent low-temperature heat sealability (laminated with the slippery layer as the surface) has excellent blocking resistance and is used in a non-powder state. However, roll-blocking of the laminate did not occur, and the bag-manufactured product obtained from the above-mentioned laminated film had good opening property.

Comparative Example 1 A biaxially stretched polyamide film was obtained in the same manner as in Example 1 except that the slippery layer was not provided. The characteristics of the obtained polyamide film are shown in Table 1. The film obtained in this comparative example was inferior in slipperiness. Further, the laminate of the film obtained in this Comparative Example and the LLDPE film having excellent low temperature heat sealability was inferior in blocking resistance and could not be used without powder.

(Comparative Example 2) A laminated polyamide film was obtained in the same manner as in Example 1 except that polyethylene wax was not added to the coating solution for the slippery layer. The characteristics of the obtained laminated polyamide film are shown in Table 1. The slipperiness of the laminated polyamide film obtained in this Comparative Example was superior to the film of Comparative Example 1, but inferior to the film of Example 1.

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

(Production of Polyester Polyol) In a stainless steel autoclave equipped with a stirrer, a thermometer and a partial reflux type condenser, dimethyl terephthalate: 543 parts, neopentyl glycol: 458 parts, ethylene glycol: 410 parts and tetra-n- Butyl titanate: 0.52 parts was charged and the transesterification reaction was carried out at 160 to 220 ° C for 4 hours. Then, 23 parts of fumaric acid and 51 parts of sebacic acid were added to obtain 200
The temperature was raised from 0 ° C to 220 ° C over 1 hour to carry out an esterification reaction. Next, the temperature was raised to 255 ° C., the pressure of the reaction system was gradually reduced, and then the reaction was performed under reduced pressure of 0.5 mmHg for 30 minutes to obtain a polyester polyol (A-1). The obtained polyester polyol (A-1) was light 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 Neopentyl 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 and dissolved in a reactor equipped with a thermometer, a stirrer and a reflux condenser together with 120 parts of methyl ethyl ketone. After that, neopentyl glycol: 3 parts, isophorone diisocyanate: 15 parts, dibutyltin laurate: 0.02
A part was 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 metered dropping device, a solution of the polyurethane (B-1) obtained above in methyl ethyl ketone (solid content concentration: 50%). : 150 parts, Iropropyl alcohol: 15 parts, and heated to 65 ° C., then a mixture of methacrylic acid: 17.5 parts and ethyl acrylate: 7.5 parts, and azobisdimethylvaleronitrile: 1.2 A solution prepared by dissolving 25 parts of methyl ethyl ketone in a mixed solution of 25 parts of methyl ethyl ketone and 5 parts of isopropyl alcohol was added dropwise to the polyurethane solution at a rate of 0.2 ml / min, and stirring was continued at the same temperature for 2 hours. After sampling for analysis (5 g) from the reaction solution, 300 parts of water and 25 parts of triethylamine were added to the reaction solution and stirred for 1 hour to obtain an aqueous dispersion. Then raise the temperature of the dispersion to 100 ° C.,
Methyl ethyl ketone, isopropyl alcohol and excess triethylamine were removed by distillation. The produced aqueous dispersion (C-1) was white and had a B-type viscosity of 50 cps.
(25 ° C.), which was a dispersion liquid in which fine particles having an average particle diameter of 300 nm were uniformly dispersed. The characteristics of the obtained laminated polyamide film are shown in Table 1. The laminated polyamide film obtained in this example had excellent slipperiness.

(Comparative Example 3) A laminated polyamide film was obtained in the same manner as in Example 1 except that polyethylene wax was not added to the coating solution for the slippery layer in the method of Example 2. The characteristics of the obtained laminated polyamide film are shown in Table 1. The slipperiness of the laminated polyamide film obtained in this comparative example was inferior to that of the laminated polyamide film of the example.

(Example 3) In the method of Example 1, the coating liquid for the slippery layer was changed to polyethylene wax to have a molecular weight of 2
A laminated polyamide film was obtained in the same manner as in Example 1 except that the compounding ratio of the acid-modified polyethylene wax of 000 was 97: 3. The characteristics of the obtained laminated polyamide film are shown in Table 1. The laminated polyamide film obtained in this example was also excellent in slipperiness.

Example 4 In the method of Example 1, the composition of the coating liquid for the slippery layer was a water-dispersible polyester resin (Vylonal MD16 manufactured by Toyobo Co., Ltd.) and polyethylene wax in a ratio of 95: 5. A laminated polyamide film was obtained in the same manner as in Example 1 except that The characteristics of the obtained laminated polyamide film are shown in Table 1. The laminated polyamide film obtained in this example was also excellent in slipperiness.

(Comparative Example 4) A laminated polyamide film was obtained in the same manner as in Example 4 except that the blending of the polyethylene wax in the coating solution for the slippery layer was stopped by the method of Example 4.
The characteristics of the obtained laminated polyamide film are shown in Table 1.
The laminated polyamide film obtained in this comparative example had poor slipperiness.

(Example 5) In the method of Example 1, the composition of the coating liquid for the slippery layer was a mixture of a water-dispersible polyurethane resin (Dainippon Ink and Hydran HW350) and acid-modified polyethylene wax 95: 5. A laminated polyamide film was obtained in the same manner as in Example 1 except that The characteristics of the obtained laminated polyamide film are shown in Table 1. The laminated polyamide film obtained in this example was also excellent in slipperiness.

Comparative Example 5 A laminated polyamide film was obtained in the same manner as in Example 5, except that the acid-modified polyethylene wax in the coating liquid for the slippery layer was stopped by the method in Example 5. The characteristics of the obtained laminated polyamide film are shown in Table 1. The laminated polyamide film obtained in this comparative example had poor slipperiness.

[0071]

[Table 1]

[0072]

The laminated polyamide film of the invention according to claim 1 is excellent in slipperiness, particularly slipperiness in a high humidity atmosphere. The laminated polyamide film according to the second aspect of the invention is excellent in a high degree of slipperiness, particularly in a high humidity atmosphere. According to the method for producing a laminated polyamide film of the invention as set forth in claim 3, it is possible to easily produce a laminated polyamide film having a uniform slippery layer and excellent in slipperiness, particularly in a high humidity atmosphere. can do. According to the method for producing a laminated polyamide film of the invention as set forth in claim 4, a laminated polyamide film having a uniform and easily slippery layer, particularly excellent in slipperiness especially in a high humidity atmosphere, can be easily produced. can do.

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Claims (4)

[Claims] 1. A laminated polyamide film comprising a base layer made of a polyamide film and an easily slipping layer made of a mixture of a water-soluble or water-dispersible resin and a polyolefin wax laminated on at least one surface of the base layer. . 2. The water-soluble or water-dispersible resin is a graft copolymer resin composed of polyester and an acrylic polymer, or a graft copolymer resin composed of polyurethane and an acrylic polymer. The laminated polyamide film described. 3. A laminate characterized by applying an aqueous solution of a water-soluble or water-dispersible resin or a coating solution containing a polyolefin wax mixed to an aqueous dispersion on at least one side of an unstretched polyamide film, and then biaxially stretching. Method for producing polyamide film. 4. A uniaxially stretched polyamide film is coated on at least one surface thereof with an aqueous solution of a water-soluble or water-dispersible resin or a coating liquid containing a polyolefin wax and the stretching direction of the uniaxially stretched polyamide film is A method for producing a laminated polyamide film, which comprises drawing in a direction at a right angle.