JPH0336030A - Easy adherent polyester film and manufacture thereof - Google Patents

Abstract

PURPOSE:To make it possible to form polyester film full of excellent adhesion to ultraviolet-curing resin, especially to shearing force by a method wherein specified easy adherent layer is provided at least on one side of the polyester film. CONSTITUTION:At least on one side of polyester film, easy adherent layer, which is produced by copolymerizing the following components one another and contains copolymer having the secondary transition point of 10-60 deg.C, is provided. The components are as follows: (a) 70 - 99wt.% of component represented by the formula I, in which R1 represents hydrogen atom (-H) or methyl group (-CH3) and R2 represents acid group (-COOR3) having straight alkyl (R3) chain or branched alkyl (R3) chain with the number of carbon atoms of 1 - 20, benzene nucleus represented by the formula II, or cyano (-CidenticalN), (b) 1 - 10wt.% of N-methylol (meth)acrylamide (c) 0 - 5wt.% of ethylene-based compound, the molecule of which contains carboxyl group, (d) 0 - 29wt.% of compound, which is copolymerizable with said compounds in (a) - (c) excluding said compounds in (a) - (c). Water-based coating liquid, which contains fine particles having the weight-average particle diameter of 0.01 - 0.3mum, is applied on the easy adherent layer. The resultant film is dried, stretched and heat-treated so as to complete the crystal orientation of the polyester film in order to obtain the aimed film, on which the easy adherent layer is provided.

Description

[Detailed Description of the Invention] <Industrial Field of Application> The present invention relates to an easily adhesive polyester film and a method for producing the same, and more specifically, it relates to an easily adhesive polyester film and a method for producing the same, and more particularly, it relates to an easily adhesive polyester film and a method for producing the same. The present invention relates to an easily adhesive polyester film exhibiting good adhesion to and a method for producing the same.

<Prior art> Polyester films, especially biaxially stretched films of polyethylene prephthalate, have excellent mechanical properties, Iw maturation properties, and chemical resistance, so they can be used for magnetic tapes, photographic films, packaging films, metallizing films for capacitors, The growth in demand for it as a material for electrical insulation films, OHP films, information recording cards, etc. has been particularly remarkable in recent years. However, polyester film has high surface cohesiveness due to its crystal orientation, and has extremely poor adhesion to various paints.

Therefore, methods such as corona treatment, plasma treatment, and flame treatment are known as methods for modifying the surface properties of polyester films, but these methods have the disadvantage that their performance deteriorates over time. One way to overcome this drawback is to use drugs to break the crystallinity. However, there are problems in practical use, such as the chemical being toxic and the volatilization of its vapor causing environmental pollution.

Another known method is to provide a primer layer by applying an easily adhesive coating onto a biaxially stretched polyester film. However, this method also involves safety and hygiene problems such as environmental pollution due to solvent volatilization, and the risk of frequent coating film surface defects due to dust adhesion because the coating atmosphere is dirty.

Therefore, if this primer treatment is performed during the polyester film production process using a water-based coating agent, there will be less dust adhesion in a clean environment, and there will be no risk of explosion or environmental pollution due to the number of water-based coatings, and the performance of the film will be improved. It is also advantageous in terms of economy and safety.

Because of these advantages, it has been proposed to use water-soluble or water-dispersible polyurethane or copolymerized polyester resins as primers. However, the primer layer has the disadvantage that the films block each other due to changes in temperature and humidity during storage. In addition, the adhesive strength to ultraviolet curing resins such as acrylic resins, especially the adhesive strength against shearing force, is extremely poor.

<Object of the Invention> The first object of the present invention is to provide a polyester film 11 that has excellent adhesion to ultraviolet curable resins such as acrylic resins, especially adhesion to front shearing force. . A second object of the present invention is to provide a method for efficiently producing such a polyester film.

<Structures/Effects of the Invention> According to the present invention, the objects of the present invention are: 1. An easily adhesive film having an easily adhesive layer provided on at least one side of a polyester film 11, wherein the easily adhesive layer is (a). ) Compound represented by the following formula (I) 1 CH2-C-R2...<I> 70-99% by weight, (bl methylol(meth)acrylamide-10% by weight, (e
) Ethylene compound having a carboxyl group in the molecule 0
~5% by weight and (d) copolymerizable with the above (al~(C) compound) and copolymerized with 0~29% by weight of a compound other than said compound, with a secondary transition point of 10~60°C An easily adhesive polyester film characterized by containing a copolymer having (Tg>).

2. Before completing the crystal orientation, apply an aqueous coating solution containing fine particles made of the copolymer described in 1 above and having a weight average particle size of 0.01 to 0.3 μm on at least one side of the polyester film, and then A method for producing an easily adhesive polyester film, which comprises drying, stretching, and heat-treating the polyester film to complete the crystal orientation of the polyester film to obtain a film provided with an easily adhesive layer.

achieved by

The polyester constituting the film in the present invention is
It is a linear saturated polyester synthesized from an aromatic dibasic acid or its ester-forming derivative and a diol or its ester-forming derivative. Specific examples of such polyesters include polyethylene terephthalate, polybutylene terephthalate, polyethylene isophthalate, poly(I4-cyclohexylene dimethylene terephthalate), polyethylene-2,6-phthalenosica l levoxylate, etc. Copolymers of these or Blends of these and small proportions of other resins are also included.This polyester can contain inorganic or organic fine particles in order to improve the slipperiness of the film and impart light-shielding properties. Such fine particles include titanium oxide,
Examples include inorganic fillers such as calcium carbonate, silica, barium sulfate, and carbon black, and organic fillers such as silicone, acrylic, benzoguanamine, Teflon, and epoxy. Furthermore, an agent that imparts easy adhesion and antistatic properties, such as polyethylene glycol and sodium dodecylbenzenesulfonate, can be included.

The polyester film of the present invention can be obtained by melt-extruding such a polyester into a film, and performing oriented crystallization by longitudinally and transversely biaxially stretching and crystallization by heat treatment.

The copolymer constituting the easily adhesive layer of the present invention is a compound represented by the following formula (I) (a) l CH2=C 2 ... (I), (b) N-methylol (meth)
Acrylamide, (C1 an ethylene compound having a carboxyl group in the molecule and (d) a compound that can be copolymerized with the compounds (a) to (C) above and is copolymerized with a compound other than the above compounds at a predetermined ratio) , and has a secondary transition point (Tg) of 10 to 60°C.

As the compound (a) represented by the above formula (I), R1
is a hydrogen atom or a methyl group, and R2 is C00
Examples include alkyl ester compounds of acrylic acid or methacrylic acid represented by R3 (wherein the crest is a straight chain or branched alkyl group of C1 to C2o). Among these compounds, in the case of acrylic ester compounds, the peak is preferably a linear or branched alkyl group of 01 to Cxo, and such alkyl groups include, for example, methyl group, ethyl group, l-propyl group, isopropyl group, II-butyl group, isobutyl group, 1
-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, 2-ethylhexyl group, n-
Examples include a nonyl group, an isononyl group, and an n-decyl group. Specifically, for example, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, isononyl acrylate, etc. can be used.

In the case of methacrylic acid ester compounds, the peak is preferably a 01-C20 straight chain or branched alkyl group, more preferably a C1-C4 straight chain or branched alkyl group, and such Examples of alkyl groups include methyl group, ethyl group, n~propyl group,
Examples include isopropyl group, rl-butyl group, isobutyl group, and specifically, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, and the like.

Also, the above combination! Examples of tk (a) include aromatic vinyl compounds in which R1 is a hydrogen atom or a methyl group and R2 is a phenyl group, such as styrene, α-methylstyrene, vinyltoluene, ethylvinylbenzene, etc. Furthermore, vinyl cyanide compounds in which R2 is a cyano group, such as acrylonitrile and methacrylaterile, can also be used.

The usage amount of these compounds (a) is as follows: Compounds (a) to (d)
It is 70 to 99% by weight, preferably 75 to 95% by weight, based on the total 100% by weight.

The compound (b) includes N-methylol acryl;
Amide and N-methylol methacrylamide. These may be used alone or in combination to form compounds (a) to (d).
), it is necessary to contain 1 to 10% by weight, preferably 1-6% by weight, based on 100% by weight.

Examples of the compound (C) include C3 to C5 α, β-mono- or mono-unsaturated carboxylic acids such as acrylic acid, methacrylic acid, lyrotonic acid, citraconic acid, itaconic acid, maleic acid, fumaric acid; Anhydrides of C3 to C5 alpha, beta cine saturated carboxylic acids such as maleic anhydride;
Monoalkyl esters of alpha, beta-cine saturated carboxylic acids to C3 and C5 such as monobutyl maleate, monobutyl fumarate, monoethyl itaconate; for example, ethylene carboxylic acids such as sodium acrylate, ammonium methacrylate, etc. or (χ, β-cine saturated carboxylic acid monoalkyl Nisderian compound ammonium salt or alkali metal salt, etc.). These compounds (
The amount of C) used is 0 to 5% by weight, preferably 0.5 to 3% by weight, based on the total weight of 100% of the compound (al to (dl).

Examples of the compound (d) include amides of ethylene carboxylic acids such as acrylamide, methacrylamide, diacetone acrylamide, etc.; esters of ethylene carboxylic acids and alcohols having an epoxy group such as glycidyl acrylate, glycidyl methacrylate, etc. For example, 2-hydroxyethyl acrylate, 2
-Hydroxyalkyl esters of ethylene carboxylic acids such as hydroxy 10-pyl acrylate, 2-hydroxyethyl methacrylate; esters of ethylene carboxylic acids and alcohols having an amino group, such as dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, etc. ; For example, divinylbenzene,
Compounds containing two or more unsaturated groups such as diallyl phthalate, triallyl cyanurate, diethylene glycol dimethacrylate and the like can be mentioned. The usage amount of these compounds (d) is as follows: Compounds (a) to (
It is 0 to 29% by weight based on the total 100% by weight of d).

The copolymers of the present invention are usually available as aqueous dispersions.

This "aqueous dispersion" is a (co)polymer obtained by emulsion polymerizing a compound appropriately selected from the above compound group (al. to (d)) in an aqueous medium in the presence of a surfactant or protective colloid. The combined aqueous dispersion may be a single aqueous dispersion, or a blend of aqueous dispersions of a plurality of these (co)polymers.

For use 1 of surfactants, the above compounds (al to fd
It is usually used in an amount of about 0.5 to about 7 parts by weight based on a total of 10,041 parts of l, and is used to improve the polymerization stability of aqueous emulsion copolymerization, the storage stability of an aqueous copolymer dispersion, and the acrylic resin targeted by the present invention. It is preferable to use about 1 to about 5 parts by weight in order to obtain adhesion to ultraviolet curable resins such as exemplified by, especially adhesion to shear force.

In addition, the amount of the protective colloid used is as follows:
An example is an amount of 0 to 3 parts by 1 part based on a total of 100 parts by weight of ) to (d).

Examples of such surfactants include nonionic surfactants such as polyoxyalkylene alkyl ethers such as polyoxyethylene lauryl ether and polyoxyethylene stearyl ether; polyoxyethylene octylphenol ether and polyoxyethylene nonylphenol ether; polyoxyalkylene alkylphenol ethers such as; sorbitan fatty acid esters such as sorbitan monolaurate, sorbitan monostearate, sorbitan trioleate; polyoxyalkylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monolaurate; polyoxyethylene Polyoxyalkylene fatty acid esters such as monolaurate, polyoxyethylene monostearate, etc.; glycerin fatty acid esters such as oleic acid monoglyceride, stearic acid monoglyceride, etc.; polyoxyethylene, polybrobylene block copolymer; etc. and anionic surfactants such as fatty acid salts such as sodium oleate; alkylaryl sulfonates such as sodium dodecylbenzenesulfonate; alkyl sulfate ester salts such as sodium lauryl sulfate; monooctylsulfosuccinate; Alkyl sulfosuccinate ester salts and derivatives thereof such as acid soda, dioctyl sodium sulfosuccinate, polyoxyethylene lauryl sulfosuccinate sodium ester, etc.; polyoxyalkylene alkyl ether sulfate ester salts such as polyoxyethylene lauryl ether sodium sulfate; polyoxyethylene Polyoxyalkylene alkylaryl ether sulfate salts such as nonylphenol needle sodium sulfate; etc. as cationic surfactants;
For example, alkylamine salts such as laurylamine acetate; quaternary ammonium salts such as lauryltrimethylammonium chloride, alkylbenzyldimethylammonium chloride; polyoxyethylalkylamine; and examples of amphoteric surfactants such as lauryl Examples include alkyl betaines such as betaine. Furthermore, surfactants in which some of the hydrogen atoms in the alkyl groups of these surfactants are replaced with fluorine can also be used. Furthermore, so-called reactive surfactants having a radically polymerizable double bond in the molecular structure of the surfactant can also be used.

Examples of the protective colloid include polyvinyl alcohols such as partially saponified polyvinyl alcohol, completely saponified polyvinyl alcohol, and modified polyvinyl alcohol; cellulose derivatives such as hydroxyethyl cellulose, hydroxypropyl cellulose, and carboxymethyl cellulose salt; and Examples include natural polysaccharides such as guar gum.

Furthermore, the term "in an aqueous medium" means in water or in an aqueous solution of a water-soluble organic solvent, and examples of such water-soluble organic solvents include methyl alcohol, ethyl alcohol, and ethyl alcohol. Water-soluble alcohols such as alcohol and isopropyl alcohol; Water-soluble ketones such as acetone; Methyl cellosolve, cellosolve,
Water-soluble ethers such as butyl cellosolve, calpitol, butyl carpitol, etc. can be used alone or in combination. The amount to be used is determined based on the concentration of the water-soluble organic solvent in the aqueous solution of 0 to about 5. From the viewpoint of obtaining adhesion to, particularly adhesion to, shear force, it is preferable to carry out the emulsion polymerization in water substantially free of these organic solvents.

Furthermore, in emulsion polymerization, persulfates such as ammonium persulfate, potassium persulfate, ammonium persulfate, etc.; organic peroxides such as tertiary butyl hydroperoxide, cumene hydroperoxide, para-menthane hydroperoxide, etc.; It is preferable to use one or more polymerization initiators such as hydrogen peroxide. This amount is 0.05 to 1 part by weight, more preferably 0.1 to 0.7 part by weight, particularly 0.1 to 0.5 part by weight, based on the total 100 parts by weight of the compound (al to (dl). It is preferable that there be.

Further, in the emulsion polymerization, a reducing agent can be used in combination if desired. Examples include reducing organic compounds such as ascorbic acid, tartaric acid, citric acid, glucose, etc.; reducing inorganic compounds such as sodium thiosulfate, sodium sulfite, sodium bisulfite, sodium metabisulfite, etc. The amount used can be selected as appropriate, but for example, about 0.0 parts by weight per 100 parts by weight of the compounds (a) to (d) used.
Examples include amounts such as 5 to about 1 part by weight.

The "copolymer aqueous dispersion" used in the present invention is a single (co)polymer emulsion obtained in this way or a plurality of (
Blends of co>polymer emulsions are preferred.

The copolymer thus obtained has a second-order transition point (Tg) of 1
It is a polymer that has a temperature of 0 to 60°C, or even 20 to 50°C. When this secondary transition point is less than 10°C, it is difficult to obtain adhesion to ultraviolet curable resins such as acrylic resins, which is the object of the present invention, especially adhesion to shear force, which is undesirable; When this is the case, it is difficult to obtain sufficient film strength due to poor film forming properties, etc., and it is difficult to obtain the desired effects of the present invention, which is not preferable.

Furthermore, the (weight i) average particle diameter of the copolymer is 0.01 to 0.01
μm, preferably 0.05 to 0.2 μm. The t(
If the average particle diameter of the polymer is less than the above lower limit, it is not preferable because a large amount of aggregates or gelation will occur when the copolymer is subjected to aqueous emulsion polymerization as described above. When the average particle diameter exceeds the above upper limit, it is difficult to obtain adhesion to ultraviolet curing resins such as acrylic resins, especially adhesion to shear forces, which is undesirable. .

The easily adhesive water-based anchor coat according to the present invention can be applied as it is or after being appropriately diluted with water or the like, to at least one side of a polyester film before crystal orientation is completed. In this case, it is possible to use a surfactant as a wetting agent in combination as necessary, and it is also possible to use polyvinyl alcohol, a cellulose derivative, a polycarboxylic acid resin, a surfactant, etc. as a thickening agent. .

Furthermore, the easily adhesive water-based anchor coating agent in the present invention may be an aqueous solution of a resin such as an epoxy resin, an amine resin, a polyester resin, a polyurethane resin, or a blocked incyanate resin, if desired, within a range that does not impede the effects of the present invention. Aqueous dispersions can be formulated, and organic or inorganic fillers, pigments, dyes such as titanium oxide, clay talc, calcium carbonate, silica, aluminum hydroxide, asbestos, carbon black and phthalocyanine blue, butyl cellosolve, butyl carpi There is no problem in adding film-forming aids such as Thor, anti-aging agents, preservatives, ultraviolet absorbers, antistatic agents, etc.

The step of applying this aqueous primer coating liquid is preferably carried out on the surface of the polyester film immediately after melt extrusion and casting of the polymer, or fsU&, or stretching in one direction, either vertically or horizontally. The usual process is to apply a primer layer on a uniaxial film stretched in the vertical direction, then horizontally stretched while heating.
Further, the film is heat-set at a high temperature and the primer layer is completely cured. Any known method can be used to coat the primer layer on the polyester film. For example, a spray coating method, an air knife method, a reverse coating method, a kiss coating method, a gravure coating method, a Meyer bar method, a roll plush method, etc. can be applied. The concentration of the applied coating fluid varies depending on the coding method, but is generally between 0.5 and 50% by weight.・≦. The coating amount is preferably 1 to 20 g wet i, -'nf.

The film of the present invention has excellent adhesion to ultraviolet curing resins such as acrylic resins, especially adhesion to shear forces. Therefore, general industrial applications such as telephone cards and other cards, abrasive tapes, chemical matte films, membranes, diazo photosensitive films, labels, OHP films, and magnetic materials such as video tapes, audio tapes, computer tapes, floppy disks, etc. Useful as a base material for tapes.

<Examples> The present invention will be explained in detail below using examples. Note that various values in the specification were measured as follows. Furthermore, "parts" in the examples represent parts by weight.

+1+ After printing an ultraviolet curable printing ink, Toyo Ink FDO Beni APNI, on a polyester film coated with an aqueous dispersion of adhesive copolymer, using a RI tester (Mei Seisakusho), a medium pressure mercury lamp (80 W/cm, - lamp) was used. Curing is performed using a JV curing device (Formula: Nippon Battery) to form a UV ink layer with a thickness of 4.5 μm.

Evaluation: 1) 18m/m I on top of this UV ink layer
100m/mi with cellotape (Nichiban)
180° reverse peeling was performed at a high speed of n, and the peeling load (, g
/18m/n).

Evaluation: 2) Scratch this UV ink layer with your fingernail and indicate the degree of scratching on a 5-level scale. (Good; 5H1; Bad) Examples 1 to 4 Contains 10% by weight of anatase titanium oxide with an average particle size of 0.2 μm and 1% by weight of silica with an average particle size of 4 μm,
Polyethylene terephthalate having an intrinsic viscosity of 0.55 as measured in orthochlorophenol at 25°C is extruded from a T-die, and cooled on a drum maintained at 40°C while applying electrostatic charge to a thickness of 2.5°C. A 4 mm unstretched film was made, and then heated to 90°C and stretched to 3.0 mm in the machine direction.
The film was stretched twice, and then a coating solution having the composition shown below was coated on the uniaxially stretched film by a kiss coating method.

Composition of coating liquid> ■ Copolymer resin shown in Table 1 90 parts by weight ■ Nonionic surfactant 10 parts by weight (NOF) Nion NS-208,51 The wet coating amount at this time was 1. It was 5%×10.7g/po.

Thereafter, it was laterally stretched to 3.2 times at 110°C, and then stretched at 230°C.
A biaxially stretched (easily adhesive) polyester film having a thickness of 250 μm was obtained by heat treatment at °C.

The performance of this film is shown in Table 1.

No. table The abbreviations in the above table are as follows.

MMA, methyl methacrylate EA; ethyl acrylate 6N; acrylonitrile N-MAM; N-methylolacrylamide MAA; methacrylic acid Comparative Example 1 For comparison, the performance of a polyester film not coated with any coating liquid is shown in Table 2. show.

As is clear from Table 2, the aqueous copolymer dispersion-coated film of the present invention exhibits excellent adhesive performance, especially adhesive performance against shear forces.

Claims (1)

[Scope of Claims] 1. An easily adhesive film comprising an easily adhesive layer provided on at least one side of a polyester film, the easily adhesive layer comprising (a
) The following formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼... (I) [In the formula, R_1: -H or -CH_3 R_2: -COOR_3 (here, R_3 is the number of carbon atoms from 1 to
20 straight or branched alkyl), ▲Mathematical formulas, chemical formulas, tables, etc.▼ or -
C≡N] 70 to 99% by weight of the compound represented by (b) 1 to 10% by weight of N-methylol (meth)acrylamide, (c)
Ethylene compound having carboxyl group in molecule 0~
5% by weight and (d) copolymerizable with the compounds (a) to (c) above and 0 to 29% by weight of a compound other than said compound, with a secondary transition point of 10 to 60°C ( An easily adhesive polyester film comprising a copolymer having a Tg). 2. Applying an aqueous coating solution containing fine particles made of the copolymer according to claim 1 and having a weight average particle size of 0.01 to 0.3 μm on at least one side of the polyester film before completion of crystal orientation, and then A method for producing an easily adhesive polyester film, which comprises drying, stretching, and heat-treating the polyester film to complete the crystal orientation of the polyester film to obtain a film provided with an easily adhesive layer.