JPH09143293A - Easily slippery polyamide resin film having excellent printability and method for producing the same - Google Patents

Abstract

(57) [PROBLEMS] To provide a polyamide resin film having excellent printability and good slipperiness, and a method for producing the same. SOLUTION: The surface tension on one side is 40 dyne / cm.
In the above polyamide-based resin film, the static friction coefficient of the one-side surface and the opposite surface thereof at a humidity of 50% is 1.0 or less, and the humidity is 50%.
Disclosed is a slippery polyamide-based resin film excellent in printability, which has a ratio (B) / (A) of the static friction coefficient (A) at 65% to the static friction coefficient (B) at 65%, and a method for producing the same. To do.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polyamide resin film having excellent printability and good slipperiness.

[0002]

2. Description of the Related Art Polyamide-based resin films are excellent in mechanical properties including toughness and bending resistance, optical properties, thermal properties, gas barrier properties, etc. Widely used. However, the polyamide-based resin film has a high hygroscopicity as a difficulty derived from the characteristics of the polyamide-based resin itself, and when used in a high-humidity environment, the hygroscopicity lowers the slipperiness and the workability during processing is significantly impaired. There is.

In recent years, full-scale printing and multicolor printing have become widespread as the packaging products have become more sophisticated, and a high degree of printability is required to adapt to such situations. Therefore, in order to meet such requirements, a method of increasing the printability by subjecting the surface of the polyamide resin film to a surface activation treatment such as corona discharge is adopted.

However, when such a surface activating treatment is applied, the slipperiness of the treated surface is further deteriorated. Therefore, as a means for overcoming these difficulties, a method of lowering the coefficient of friction of the friction surface between the films or the material in contact with the film is adopted. A method is adopted in which active inorganic or organic fine particles are contained or a thermoplastic resin which is incompatible with polyamide is contained to reduce the friction coefficient of the film surface.

However, with these methods, the slipperiness of the film is improved, but the printability cannot be increased, and a polyamide resin film satisfying both the requirements of printability and slipperiness cannot be obtained.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and its object is to provide a polyamide resin film capable of satisfying both printability and slipperiness at the same time. It is intended to provide the manufacturing method.

[0007]

The slippery polyamide resin film having excellent printability according to the present invention capable of achieving the above object has a surface tension on one side of 40 dyn.
In a polyamide-based resin film having a rate of e / cm or more, the one-side surface and the other-side surface have a humidity of 50%.
Where the static friction coefficient is 1.0 or less and the ratio (B) / (A) of the static friction coefficient (A) at 50% humidity and the static friction coefficient (B) at 65% humidity is 2.0 or less. Has its characteristics.

As a preferred specific example of the polyamide resin film, a slippery layer containing a graft copolymer composed of polyester and an acrylic polymer as a main component is formed on the opposite surface side of the film to provide smoothness. Or an easy-slip layer having a graft copolymer composed of polyester and an acrylic polymer as a main component is formed on both sides of the film, and only one side thereof is subjected to a surface activation treatment. The thing raised to the surface tension of 40 dyne / cm or more is mentioned.

The slippery polyamide resin film excellent in printability is subjected to a surface activation treatment on one surface of a base material film made of a polyamide resin to increase the surface tension to 40 dyne / cm or more, and the other. On the opposite surface side, a method of forming an easy-sliding layer containing a graft copolymer composed of polyester and an acrylic polymer as a main component, and both surfaces of a base film made of a polyamide resin,
After forming the slippery layer containing a graft copolymer composed of polyester and an acrylic polymer as a main component, one surface side thereof is subjected to a surface activation treatment to have a surface tension of 40 dyne /
It can be manufactured by a method of increasing the thickness to cm or more.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION As described above, according to the present invention, one side of a polyamide resin film has a surface tension of 40 dyne / cm or more and has excellent printability.
Moreover, as a requirement for improving slipperiness, the coefficient of static friction between the surface on one side and the surface on the opposite side under a specific humidity atmosphere is specified, whereby a polyamide that satisfies printability and slipperiness at the same time. It succeeded in obtaining a resin film.

The structure of the polyamide resin film according to the present invention will be described in detail below. First, the polyamide-based resin that constitutes the base film in the present invention has polyamide as a main component, and examples of the polyamide include polyamides obtained by polycondensation of lactams having three or more membered rings, and ω-amino acids. Examples thereof include polyamides obtained by polycondensation and polyamides obtained by polycondensation of dibasic acid and diamine. Specific examples of the 3- or more-membered lactams used here include ε
-Caprolactam, enantolactam, capryllactam, lauryllactam and the like; specific examples of ω-amino acids include 6-aminocaproic acid, 7-aminoheptanoic acid,
9-aminononanoic acid, 11-aminoundecanoic acid and the like;
Specific examples of the dibasic acid include adipic acid, glutaric acid,
Pimelic acid, suberic acid, azelaic acid, sebacic acid,
Undecanedioic acid, dodecadioic acid, hexadecadioic acid, eicosandioic acid, eicosadiendioic acid,
2,2,4-trimethyladipic acid, terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic 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, metaxylylenediamine and the like;

Polymers obtained by polycondensing these or copolymers thereof include nylon 6, nylon 7, nylon 11, nylon 12, nylon 6,6, nylon 6,9, nylon 6,11, Nylon 6,12,
Nylon 6T, Nylon 6I, Nylon MXD6, Nylon 6 / 6,6, Nylon 6/12, Nylon 6/6
T, nylon 6 / 6I, nylon 6 / MXD6 and the like.

The base film contains the above polyamide resin as a main component, and as long as its purpose and performance are not impaired,
Of course, known additives such as antioxidants, weather resistance improvers, anti-gelling agents, lubricants, anti-blocking agents, pigments, antistatic agents, and surfactants may be contained.

The substrate film containing the polyamide-based resin as a main component can be produced by, for example, the T-die method or the inflation method.
It can be formed into a film by a known method. This film may have a single-layer structure or a multilayer structure by a co-extrusion method or the like.

It is necessary that one surface of the base film is raised to a surface tension of 40 dyne / cm or more, more preferably 42 dyne / cm or more by surface activation treatment, and the surface tension is 40 dyne / cm. If it is less than the above, satisfactory printability cannot be ensured. The specific method of the surface activation treatment is not particularly limited, and corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, flame treatment and the like can be used alone or in combination as required.

In the polyamide resin film of the present invention, in addition to specifying the surface tension on one side for ensuring printability, as a requirement for ensuring slipperiness, the surface activation in a specific humidity atmosphere is required. It defines the coefficient of static friction between the treated surface and the opposite side. Specifically, the static friction coefficient at the humidity of 50% on the above-mentioned activated surface and the opposite side is 1.0 or less (requirement 1), and the humidity is 50%.
Ratio (B) / (A) of static friction coefficient (A) at 65% and static friction coefficient (B) at 65% humidity is 2.0 or less (Requirement 2)
Is mandatory. The above requirement 1 is defined as a requirement for ensuring slipperiness in a normal humidity atmosphere,
Requirement 2 is defined as a requirement for ensuring excellent slipperiness even in a high-humidity atmosphere such as the rainy season, and by defining these static friction coefficient requirements,
It becomes possible to stably obtain good slipperiness regardless of the dry season and the humid season.

A more preferable static friction coefficient in an atmosphere having a humidity of 50% as defined by the above requirement 1 is 0.90 or less, more preferably 0.80 or less, and a more preferable ratio (B) of the static friction coefficient as defined by the requirement 2 above. / (A) is 1.8 or less,
It is more preferably 1.5 or less, and a film satisfying these more preferable values shows further excellent slipperiness,
Good workability is assured without causing defects due to slippage in the film processing process. When the coefficient of static friction specified in Requirement 1 exceeds 1.0, satisfactory slipperiness cannot be obtained not only in the wet season but also in the dry season, and the coefficient of static friction specified in Requirement 2 exceeds 2.0. In this case, the slipperiness is remarkably deteriorated due to moisture absorption in a humid atmosphere, and the slipperiness is remarkably changed due to the humidity change of the handling atmosphere, so that stable workability cannot be guaranteed.

As a preferable means for satisfying the requirement of the static friction coefficient defined by the above requirements 1 and 2, it is easy to use a graft copolymer composed of the following polyester and acrylic polymer as the main component on the opposite surface side. Forming a slipping layer,
There is a method in which the characteristics of the graft copolymer itself are effectively used to impart slipperiness.

Then, a graft copolymer composed of polyester and acrylic polymer, which is preferably formed (laminated) as an easily slipping layer on a polyamide resin film, will be described. In the above or the following description, the "graft copolymer" refers to a copolymer in which a branch polymer made of a polymer different from the main chain is bonded to the main chain of the trunk polymer, and also "acrylic monomer". 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. The graft copolymer can be used in the state of an organic solvent solution, an organic solvent dispersion liquid, an aqueous solvent solution, an aqueous solvent dispersion liquid, or the like, but an aqueous solvent is environmentally preferable. The "aqueous solvent" means a solvent which is mainly composed of water and which optionally contains a hydrophilic organic solvent. The main component of the slippery layer is a copolymer having one of a polyester and an acrylic polymer as a main chain polymer component and the other as a branch polymer component. First, the polyester will be described.

(Polyester) Polyester is a substantially linear polymer synthesized from a polybasic acid or its ester-forming derivative and a polyol or its ester-forming derivative. As the polybasic acid, terephthalic acid,
Aromatic dicarboxylic acids such as isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, biphenyldicarboxylic acid, 5-sodium sulfoisophthalic acid; succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid,
Aliphatic dicarboxylic acids such as dimer acid; alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, and 1,2-cyclohexanedicarboxylic acid; and acid anhydrides thereof. .

Further, it is preferable to use a dicarboxylic acid having an unsaturated double bond in the molecule in combination for graft polymerization. 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. Among them, fumaric acid, maleic acid and 2,5-norbornanedicarboxylic acid [endo-bicyclo- (2,2,1) -5-heptene-2,3-dicarboxylic acid] are preferable.

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, and when the amount is less than 0.5 mol%, radicals to the polyester are not preferable. Graft polymerization may not proceed efficiently, and when carrying out graft polymerization in an aqueous medium, the dispersed particle size may become large and the stability may deteriorate. But,
When it is used in excess of 10 mol%, the viscosity sharply increases in the latter stage of the grafting reaction, which hinders the progress of the homogeneous reaction, which is not preferable. The more preferable range of the double bond-containing dicarboxylic acid is 2 to 7 mol%, most preferably 3 to 6 in the total acid component.
Mol%.

On the other hand, specific examples of the glycol component 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-
C2-C10 aliphatic glycols such as 2-butylpropanediol; C6-C12 alicyclic glycols such as 1,4-cyclohexanedimethanol; diethylene glycol, triethylene glycol, dipropylene glycol; Of ethylene (or propylene) oxide to two phenolic hydroxyl groups of bisphenols
Glycols obtained by addition of
2-bis (4-hydroxyethoxyphenyl) propane and the like) and ether bond-containing glycols.
Further, polyethylene glycol, polypropylene glycol, polytetramethylene glycol and the like can be used. Furthermore, when a glycol having a polymerizable unsaturated bond such as an allyl ether group is used, the 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, or the like is used. Trifunctional or higher polycarboxylic acids and polyols
It is recommended that the amount is 5 mol% or less, preferably 3 mol% or less, based on the total acid component or the total glycol component. The polyester may be produced by a known transesterification method, direct esterification method or the like using the above-exemplified acid component and glycol component.

(Acrylic Monomer) As an acrylic monomer which is a constituent of the acrylic polymer grafted with the above polyester, for example, the ester moiety is a methyl group, an ethyl group, n- (or i-) propyl group, n
Non-functional (meth) acrylates such as-(or t-) butyl group, 2-ethylhexyl group, cyclohexyl group, phenyl group, benzyl group, phenylethyl group; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl Hydroxyl group-containing (meth) acrylate such as (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, N-dimethylolacrylamide, N-methoxy (meth) acrylamide, N-phenylacrylamide-containing mono. Chromatography and the like, can be used alone or in combination.

Other copolymerizable monomers may be used in combination as long as the amount is small, and such copolymerizable monomers include epoxy group-containing monomers such as allyl glycidyl ether; styrene sulfonic acid, vinyl sulfonic acid, etc. Sulfonic acid group-containing monomers and salts thereof; 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-methyl styrene, t-butyl styrene, vinyl toluene; vinyl methyl ether, vinyl trialkoxy silane, (meth) acrylonitrile, vinylidene chloride, vinyl acetate,
Vinyl chloride and the like can be exemplified, and one or more of these can be selected and used.

As the method for producing the graft polymer, the following methods are exemplified, but the present invention is not limited to those methods. (1) A method of generating a reaction initiation point of radical polymerization, cationic polymerization or anionic polymerization on a polyester and graft-polymerizing a monomer containing at least an acrylic monomer onto the polyester: for example, on a polyester molecule by light, heat or radiation. Radical polymerization method for generating radicals and then graft-polymerizing a monomer containing at least an acrylic monomer, AlCl ₃ , TiCl
_A cation is generated on the polyester molecule using a catalyst such as ₄ , and then a cationic polymerization method in which a monomer containing an acrylic monomer is graft-polymerized, or an anion is generated on the polyester molecule using metal sodium or metal lithium, Next, an anionic polymerization method or the like in which a monomer containing an acrylic monomer is graft-polymerized 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, a terminal of the main chain or a side chain, and a monomer containing at least an acrylic monomer is graft-polymerized thereto: In this method as well, the polyester is the backbone. polymer,
Then, a graft polymer in which the acrylic polymer is a 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 to obtain a polyester having a polymerizable unsaturated bond by copolymerizing sometimes used, as a method for preparing a polyester having a polymerizable unsaturated bond at the main chain terminal, a hydroxyl group at the hydroxy terminal of the polyester, A reactive group (for example, a carboxyl group, an acid anhydride group,
Acid chloride, epoxy group, isocyanate group, etc.) together with a polymerizable monomer having a polymerizable unsaturated bond. In order to introduce an unsaturated bond into the side chain, a carboxyl group or a hydroxyl group is added to the side chain portion. 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, groups that can react with a hydroxyl group are the same as described above) and a polymerizable unsaturated bond. A method of reacting a polymerizable monomer having the following formula:

(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 the functional group at the polymer chain end, 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 polymer chain end are directly reacted: When 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. By adopting the latter method, a graft polymer in which the acrylic polymer is the trunk polymer and the polyester is the branch polymer 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. Method of binding with a bifunctional coupling agent having reactivity with a group: When the former method is adopted, a graft polymer in which polyester is a trunk polymer and acrylic polymer is a branch polymer is obtained, and the latter method is adopted. Then, a graft polymer in which the acrylic polymer is the trunk polymer and the polyester is the 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 (2) above are used in combination.

Various patterns of graft polymerization methods have been described above. Among them, the polyester synthesized by a known method is preferably dissolved in an aqueous organic solvent, and a radical initiator and an acrylic monomer component are added thereto. It is a method of adding (preferably a mixture of two or more kinds) and reacting. When a carboxyl group-containing monomer (acrylic acid, methacrylic acid, etc.) is used as a part of the acrylic monomer component (about 10 to 90% by weight), the resulting graft polymer is neutralized with a base to disperse water. The body condition can be achieved, and the workability and work environment of the coating process of the slippery layer can be improved.

The aqueous organic solvent is not particularly limited as long as it is a solvent of polyester and an acrylic monomer,
Ketones, ethers, alcohols and the like having a boiling point of 50 to 250 ° C. are used. Radical initiators include benzoyl peroxide, t-butyl peroxypivalate and the like; organic azo compounds such as 2,2′-azobisisobutyronitrile and 2,2′-azobis (2,4-dimethylvaleronitrile) Etc. are illustrated. The preferred amount of radical initiator used is at least 0.2% by weight, and preferably 0.5% by weight or more, based on the monomers. It is also effective to add a chain transfer agent such as octyl mercaptan or mercaptoethanol to the acrylic monomer in an amount of about 5% by weight or less to control the graft chain length.

As the basic compound used for neutralization, a compound that volatilizes during coating film formation 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-like or solid form (pellets, powder, etc.), and then a basic compound is added. It is also possible to adopt a method of heating and stirring by throwing it into the containing water, but the most preferable is to add the basic compound-containing water immediately after the completion of the graft polymerization reaction, and then continue heating and stirring with water. Method of obtaining 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. When the molecular weights of the trunk polymer and the branch polymer deviate from the above-mentioned preferred ranges, the effect of the slipping layer containing the graft polymer becomes difficult to be exhibited.

In the present invention, the layer containing the graft polymer as described above is formed on the side of the polyamide resin film opposite to the surface activation-treated surface, so that not only under normal humidity atmosphere, but also under high humidity. It is possible to exhibit excellent slipperiness even under humidity.

The above graft polymer can be used as it is as an easily slipping layer, but it is a cross-linking agent (curing resin).
When blended with and cured, the slippery layer can be provided with a high degree of water resistance. Examples of the crosslinking agent used here include a phenol formaldehyde resin, an amino resin, a polyfunctional epoxy compound, a polyfunctional isocyanate compound or a block thereof, a polyfunctional aziridine compound, and an oxazoline compound.

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-
Examples include condensates of phenolic compounds such as phenylphenol and phenyl-o-cresol with formaldehyde.

Examples of the amino resin include an addition condensation product of urea, melamine, benzoguanamine and the like with formaldehyde, or an alkyl ether compound 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, methylol benzoguanamine and the like. And it is possible to use one kind or two or more kinds.

As the polyfunctional epoxy compound, diglycidyl ether of bisphenol A and its oligomer, diglycidyl ether of hydrogenated bisphenol A and its oligomer, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether and 1,4-butanediol. Diglycidyl ether,
Diglycidyl ethers such as 1,6-hexanediol diglycidyl ether and polyalkylene glycol diglycidyl ether; orthophthalic acid diglycidyl ester, isophthalic acid diglycidyl ester, terephthalic acid diglycidyl ester, p-oxybenzoic acid diglycidyl ester, Diglycidyl esters such as tetrahydrophthalic acid diglycidyl ester, hexahydrophthalic acid diglycidyl ester, succinic acid diglycidyl ester, adipic acid diglycidyl ester, sebacic acid diglycidyl ester; 1,4-diglycidyloxybenzene, diester Glycidyl propionurea; triglycidyl isocyanurate, trimellitic acid triglycidyl ester, glycerol triglycidyl ether, trimethylolpropane It can be exemplified such as a; Li glycidyl ether, pentaerythritol triglycidyl ether, triglycidyl ethers such as triglycidyl ether of glycerol alkylene oxide adducts.

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 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, hydrogenated xylylene diisocyanate, isophorone diisocyanate or trimers of these isocyanates; and polyfunctional isocyanate compounds thereof. Excess amount and low molecular weight active hydrogen compounds such as ethylene glycol, propylene glycol, trimethylolpropane, glycerin, sorbitol, ethylenediamine, monoethanolamine, diethanolamine, triethanolamine, and various polyester polyols, polyether polyols, polyamides Isocyanate compounds obtained by reacting high molecular weight active hydrogen compounds such as And the like.

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, γ-valerolactam, β-propyllactam; oximes such as acetoxime, methylethylketoxime, cyclohexanone oxime; methanol, ethanol, n- (i-, tert.
-) Propanol, alcohols such as n- (i-, tert-) butanol; ethylene chlorohydrin, 1,3
-Halogen-substituted alcohols such as dichloro-2-propanol; active compounds such as aromatic amines, imides, acetylacetone, acetoacetic acid ester, malonic acid ethyl ester, mercaptans, imines, ureas, diaryl compounds, heavy compounds Examples include sodium sulfite and the like. For blocking, the isocyanate compound and the blocking agent may be added by a known method.

As the method of blending the crosslinking agent, (1) when the crosslinking agent is water-soluble, it is directly dissolved or dispersed in an aqueous dispersion of the graft polymer, and (2) the crosslinking 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 slippery layer, a coating solution containing a graft polymer and, if necessary, a crosslinking agent is prepared by a known coating method such as a gravure method, a reverse method, a die method, a bar method or a dip method. The method of applying to the base layer may be adopted. The coating liquid may further contain additives such as an antistatic agent, an inorganic lubricant and an organic lubricant as other components within a range not impairing the characteristics of the present invention.

The slippery layer is applied / formed on a polyamide-based substrate film that has been biaxially stretched in advance, or it is applied and dried on a polyamide-based substrate film that has not been stretched or is uniaxially stretched. It is also effective to perform heat setting after the axial stretching or biaxial stretching. When a coating film is formed on the surface of a biaxially stretched substrate film, the preferred drying or heat setting temperature after application of the coating solution is 150 ° C. or higher, preferably 200 ° C. or higher, and a strong coating film under such temperature conditions. Are formed, and the adhesiveness with the polyamide resin film is improved.

When stretching is carried out after coating, the moisture content of the substrate is controlled in the range of 0.1 to 2% so that the drying property after coating does not impair the stretchability of the coating film. Also in this case, when the film is stretched and then heat-set at 200 ° C. or higher, the coating film as the slippery layer becomes stronger and the polyamide-based resin film is more firmly joined and integrated.

The coating amount of the slippery layer is 0.005 to 0.5 g / m ² , preferably 0.01 to 0.5 in terms of solid content after drying.
It is in the range of 0.2 g / m ² , and when the coating amount is insufficient, the effect expected as the slippery layer is not sufficiently exerted, and when the coating amount is too large, obstacles such as blocking are likely to occur. Become.

The polyamide-based resin film of the present invention, which is excellent in printability and slipperiness, is a polyamide-based resin film whose base is the slippery layer containing the graft copolymer of polyester and acrylic polymer as a main component. The resin film is formed on the side opposite to the surface activation treated surface, and by using the surface activation treated surface as a surface with excellent printability, excellent printability is ensured and the opposite surface side is easy to slip. It should be used as an improvement layer.

Alternatively, after forming the slippery layer containing the above-mentioned graft copolymer of polyester and acrylic polymer as a main component on both sides of the polyamide-based substrate film, only one side is treated as described above. It is also possible to increase the surface tension of the treated surface to 40 dyne / cm or more by performing surface activation treatment by the method.

At this time, in order to effectively exert the purpose of improving the slipperiness, the coefficient of static friction between the surface-activated surface and the opposite surface is 1.0 or less, preferably 0.9, as described above.
0 or less, more preferably 0.80 or less,
It is necessary to suppress the static friction coefficient ratio to 2.0 or less, preferably 1.8 or less, and more preferably 1.5 or less. By satisfying these requirements, not only in a normal humidity atmosphere but also in a humid atmosphere. Also in the above, it is possible to obtain a polyamide resin film that stably exhibits excellent slipperiness and has good printability.

[0051]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples, and the present invention is not limited thereto. Modifications can be made and implemented, all of which are included in the technical scope of the present invention. In the examples, "part" means "part by weight",
Unless otherwise specified, "%" means "% by weight". The surface tension and the static friction coefficient of the film were measured according to the following methods. [Surface tension] It was measured according to JIS-K-6768. [Coefficient of static friction of film] The coefficient of static friction of the surface-active treated surface of the film and the surface on the opposite side of the surface are
According to the method, it was measured under a humidity of 50% or 65%.

Example 1 Preparation of Polyester-Acrylic Polymer Graft Polymer (Coating Agent) Dimethyl terephthalate: 466 parts, dimethyl isophthalate: 466 in a stainless steel autoclave equipped with a stirrer, a thermometer and a partial reflux condenser. Department,
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. Next, 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. 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 and 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 stirrer, a reflux condenser and a metering dropping device, the above polyester (75 parts), methyl ethyl ketone (56 parts) and isopropyl alcohol (19) were charged and heated at 65 ° C. Dissolved. After the resin is completely dissolved, methacrylic acid: 17.5
Parts and ethyl acrylate: 7.5 parts, and a solution of azobisdimethylvaleronitrile: 1.2 parts dissolved in 25 parts of methyl ethyl ketone, added dropwise to the above polyester solution at a rate of 0.2 ml / min. And 2 more at the same temperature
Stirring was continued for 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, the temperature of the dispersion was raised to 100 ° C., and methyl ethyl ketone, isopropyl alcohol, and excess triethylamine were distilled off. The resulting aqueous dispersion was white, had a B-type viscosity of 50 cps (25 ° C.), and was a dispersion liquid in which fine particles having an average particle diameter of 300 nm were uniformly dispersed. The weight average molecular weight of the graft portion was 10,000.

(Preparation of Polyamide Resin Film and Formation of Sliding Layer) The above dispersion liquid was diluted with water so that the solid content concentration became 5% to prepare a coating liquid. On the other hand, ethylenebisstearylamide: 0.1% and average particle size 2.0μ
Polycaprolactam containing 3500 ppm of amorphous silica of m was melt extruded from a T die and cooled on a drum at 30 ° C. to obtain an unstretched polyamide film having a thickness of 150 μm. Next, this unstretched film was longitudinally stretched 3.1 times at 50 ° C. The uniaxially stretched film thus obtained was coated on one side with the coating solution for a slippery layer described above with 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 thickness of the slippery layer was 0.05 μm, and the thickness of the polyamide resin film was 15 μm. Corona treatment is applied to the non-coated surface where the slippery layer is not formed, and the surface tension is set to 48dy.
It was ne / cm. The characteristics of this film are as shown in Table 1, and were excellent in both printability and slipperiness.

Comparative Example 1 A biaxially stretched polyamide resin film was obtained in the same manner as in Example 1 except that the slippery layer was not provided.
The characteristics are as shown in Table 1, and the static friction coefficient at a humidity of 65% was large, and the static friction coefficient ratio exceeded 2.0, and the slipperiness was poor.

Comparative Example 2 A biaxially stretched polyamide resin film was obtained in the same manner as in Example 1, except that the surface activation treatment was not performed. The characteristics are as shown in Table 1 and the sliding property is good, but the surface tension on the coated surface side is 38 dyne /
cm, and the printability was inferior.

Comparative Example 3 A polyester having the following composition was produced in the same manner as in the first step in Example 1. 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%

Using this polyester, it was dissolved in methyl ethyl ketone as it was without graft copolymerization to obtain a coating solution having a solid content of 5%. This coating solution is
In the same manner as in Example 1, the polyamide-based substrate film was coated on one side to prepare a biaxially stretched polyamide-based resin film. The characteristics are as shown in Table 1, and the layer formed by the above coating is made of only polyester and is not grafted with the acrylic polymer, so that the function as the slipping layer is not sufficiently exerted, Since the difference in static friction coefficient exceeded 2.0, the slipperiness was poor.

Example 2 A coating solution similar to that used in Example 1 was applied to both sides of a polyamide-based substrate film to produce a biaxially stretched polyamide-based resin film having both surfaces treated for slipperiness. Corona discharge treatment was applied to increase the surface tension to 50 dyne / cm. The characteristics of the film are as shown in Table 1, and were excellent in both printability and slipperiness.

Example 3 The same reaction as in Example 1 was carried out by changing the raw material components at the time of producing the polyester to obtain a polyester having the following composition. The glass transition temperature of the polyester was −10 ° C. 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%

Using this polyester, an acrylic polymer was graft-copolymerized in the same manner as in Example 1 to obtain an aqueous dispersion of the graft copolymer. The aqueous dispersion was white and had an average particle size of 200 nm and B at 25 ° C.
The mold viscosity was 90 cps. This aqueous dispersion was used as a coating liquid for forming a slippery layer, and a slippery layer (thickness: 0.02 μm) was formed on one surface in the same manner as in Example 1
An axially stretched polyamide resin film was obtained. The characteristics of this film are as shown in Table 1, and were excellent in both printability and slipperiness.

Example 4 The same reaction as in Example 1 was carried out by changing the raw material components at the time of polyester production to obtain a polyester having the following composition. The glass transition temperature of the polyester was −10 ° C. Dicarboxylic acid component terephthalic acid: 48 mol%, isophthalic acid: 39 mol%, sebacic acid: 9 mol%, fumaric acid: 4 mol% Diol component: neopentyl glycol: 50 mol%, ethylene glycol: 50 mol%

Using this polyester, the acrylic copolymer was graft-copolymerized in the same manner as in Example 1 to obtain an aqueous dispersion of the graft copolymer. The aqueous dispersion was white and had an average particle size of 150 nm and B at 25 ° C.
The mold viscosity was 100 cps. This aqueous dispersion was used as a coating solution for forming a slippery layer, and slippery layers (thickness: 0.02 μm) were formed on both sides in the same manner as in Example 2, and then only one side was subjected to corona discharge treatment. Then, the surface tension of the treated surface was increased to 50 dyne / cm. The characteristics of this film are as shown in Table 1, and were excellent in both printability and slipperiness.

[0064]

[Table 1]

[0065]

The polyamide resin film of the present invention is
The surface tension of one side is 40 dyne / cm or more and it has excellent printability, and by specifying the static friction coefficient at 50% humidity and the static friction coefficient ratio at 65% humidity and 50% humidity on both sides, high humidity can be obtained. It can exhibit excellent slipperiness even in an atmosphere, and can be extremely effectively used as a packaging material for various articles including foods.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical display location B32B 27/34 B32B 27/34 C08F 283/02 MQS C08F 283/02 MQS C08G 69/00 NRB C08G 69 / 00 NRB C09D 151/08 PGX C09D 151/08 PGX // B29K 77:00 B29L 9:00 (72) Inventor Mitsuru Kuwahara 2-1-1 Katata, Otsu City, Shiga Prefecture Toyobo Co., Ltd. (72) ) Inventor Tsutomu Isaka 2-8 Dojimahama, Kita-ku, Osaka Toyobo Co., Ltd.

Claims (5)

[Claims] 1. The surface tension on one side is 40 dyne / cm.
In the above polyamide-based resin film, the static friction coefficient of the one-side surface and the opposite surface thereof at a humidity of 50% is 1.0 or less, and the humidity is 50%.
The ratio (B) / (A) of the coefficient of static friction (A) in (1) to the coefficient of static friction (B) at a humidity of 65% is 2.0 or less, and an easily slipping polyamide resin film having excellent printability. 2. The slippery layer having a graft copolymer composed of polyester and an acrylic polymer as a main component is formed on the opposite surface side of the polyamide resin film. A slippery polyamide resin film with excellent printability. 3. A polyamide resin film has an easy-slip layer whose main component is a graft copolymer composed of polyester and acrylic polymer, and one surface of the polyamide resin film is treated by surface activation treatment. 40 dyne
The surface tension is increased to at least 1 / cm.
A slippery polyamide-based resin film having excellent printability according to 1. 4. The surface tension of one surface of the polyamide resin film is 40 dyne / surface by applying a surface activation treatment.
cm, and an easy-to-slip polyamide system with excellent printability, characterized in that an easy-slip layer containing a graft copolymer composed of polyester and an acrylic polymer as a main component is formed on the opposite side. Resin film manufacturing method. 5. A slippery layer comprising a graft copolymer composed of polyester and acrylic polymer as a main component is formed on both surfaces of a polyamide resin film, and one surface of the slippery layer is subjected to surface activation treatment to obtain a surface. Tension is 40 dyne / c
A method for producing a slippery polyamide resin film having excellent printability, which is characterized by increasing the thickness to m or more.