JPS63158250A - Transparent easily adhesive polyester film - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Industrial application field> The present invention relates to a transparent, easily adhesive polyester film, and more specifically to a transparent, easily adhesive polyester film, which is formed by providing a methacrylate copolymer of a specific composition as an easily adhesive primer layer. This invention relates to polyester film.

<Prior Art> It is known to melt-extrude thermoplastic polyesters, such as polyethylene terephthalate or its copolymers, polyethylene naphthalate or its copolymers, or blends of these with small proportions of black resins, to form films. be. It is also known that the resulting biaxially stretched and heat-set polyester film is superior in heat resistance, gas barrier properties, electrical properties, and chemical resistance compared to films made from the above resin. However, since the surface is highly crystal oriented, the surface has a high cohesive property, such as paint,
Poor adhesion of adhesives, inks, etc.

Therefore, physical treatment (
For example, corona treatment, ultraviolet treatment, plasma treatment, EB treatment, etc.), flame treatment, or chemical treatment (for example, alkali, amine aqueous solution).

Treatment with chemicals such as trichloroacetic acid and phenols) is known. However, these methods have practical disadvantages such as deterioration of adhesive strength over time and contamination of the working environment due to volatilization of chemicals.

Another known method is to apply a highly adhesive coating agent to the surface of the film in a process other than the usual 'II process for polyester films to provide a single layer of primer. However, with this method, organic solvents are usually used as coating solvents, and the coating atmosphere is not particularly clean, resulting in frequent surface defects on processed products due to dust adhesion, or environmental pollution caused by the solvent. Safety such as deterioration.

There are hygiene issues.

Therefore, if this primer treatment is performed during the polyester film forming process using a water-based coating agent, the film will be film-forming in a clean environment without dust adhesion, and since it is a water-based solvent, there will be no risk of explosion or environmental deterioration. It is advantageous in terms of performance, economy, and prize money.

Because of these advantages, it has been proposed to use water-soluble or water-dispersible polyester resins or acrylic resins as primers (Japanese Patent Laid-Open No. 54-4301).
No. 7, Special Publication No. 1977-10243, Japanese Patent Publication No. 1977-197
No. 86, JP-A-52-19787, etc.). However, films having a single layer of the above-mentioned resin primer often suffer from problems in which the films block each other due to changes in temperature and humidity during storage, and long-term storage requires strict management.

<Object of the invention> The object of the present invention is to provide a transparent adhesive polyester film with improved blocking resistance, and furthermore, has excellent adhesion to diazo paints and is suitable for diazo films. The object of the present invention is to provide a polyester film useful as a base.

<Configuration/Effects of the Invention> According to the present invention, an object of the present invention is to provide methyl methacrylate (A) on at least one side of a polyester film.
, ethyl methacrylate (B) and a vinyl monomer (C) copolymerizable with these, and the quantitative ratio of these satisfies the following formulas (1) and (2)% formula% (1) [ [] Easy adhesion of methacrylate copolymers 19
This is achieved by a transparent, easily adhesive polyester film characterized by having 47 layers.

In the present invention, the polyester constituting the polyester film 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, polyethylene isophthalate, and polybutylene terephthalate.

Examples include poly(1,4-cyclohexylene dimethylene terephthalate) and polyethylene-2,6-naphthalene dicarboxylate, and also include copolymers of these or blends of these with small proportions of other resins. .

The polyester film of the present invention can be obtained by melt-extruding such a linear saturated polyester resin, forming it into a film by a conventional method, and subjecting it to oriented crystallization and heat treatment crystallization. As for this polyester film, the heat of crystal fusion was measured using a differential scanning calorimeter in a nitrogen stream [10'
The value measured at a heating rate of C/min is usually 4ca.
It is preferable that the crystals are oriented to such an extent that +/g or more. The polyester film preferably has a base value of 1.5% or less when the thickness is 75 μm.

In the present invention, at least one side of the polyester film has i! (The easily adhesive primer layer consists of methyl methacrylate (A), ethyl methacrylate (8), and a vinyl monomer (C) copolymerizable with these, and the quantitative ratio of these is expressed by the following formula (1). ).

[A] /[81≦1...(1)
1.5 [A] + [BI 0.75≦□≦1.22 ... (2) [A] + [
BI +IC] is a methacrylate copolymer that satisfies the following.

If the above formula (1) is not satisfied, self-folds will occur and the transparency will decrease, making it impossible to ensure the transparency that is the objective of the present invention. Moreover, if it is smaller than the lower limit of the above formula (2), the films will block each other, and if it is larger than the upper limit, the adhesiveness will be poor and an aqueous dispersion will not be obtained, which is not preferable. (1,5(^)+
[81)/([A] + [BI + [C1)] preferably ranges from 0.94 to 1.19.

Examples of the vinyl monomer (C) constituting the methacrylate copolymer include alkyl acrylate (the alkyl group is a medyl group or an ethyl group).

n-propyl group, isopropyl group, n-butyl group.

Isobutyl group, t-butyl group, 2-ethylhexyl group,
cyclohexyl group, etc.); alkyl methacrylate (alkyl group is C3 or higher, n-propyl group, isopropyl group, n-butyl group.

Isobutyl group, t-butyl group, 2-ethylhexyl group,
cyclohexyl group, etc.): 2- and droxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate.

Hydroxy-containing monomers such as 2-hydroxypropyl methacrylate; acrylamide, methacrylamide,
N-methylmethacrylamide, N-methylacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, N-alkoxymethyl(meth)acrylamide (alkoxy group is methoxy, ethoxy, n-butoxy.

(imbutoxy, etc.), N,N-dimethylolacrylamide, N-methoxymethylacrylamide.

Amide group-containing monomers such as N-methoxymethylmethacrylamide, N-phenylacrylamide, etc.; amino group-containing monomers nigericidylacrylate such as N,N-diethylamine ethyl acrylate + N+N-diethylamine ethyl acrylate.

Epoxy group-containing monomers such as glycidyl methacrylate, allyl glycidyl ether; styrene sulfonic acid,
Vinylsulfonic acids and their salts (sodium, potassium, ammonium salts.

monolayer containing sulfonic acid groups or their salts such as tertiary amine salts; crotonic acid, itaconic acid, acrylic acid, maleic acid, fumaric acid and their salts (sodium salts, potassium salts, ammonium salts, Monomers containing carboxyl groups or their salts, such as tertiary amine salts, etc.; Monomers containing acid anhydrides, such as maleic anhydride, itaconic anhydride, etc.; Others, vinyl isocyanate,
Allyl incyanate, styrene, vinyl methyl ether, vinyl ethyl ether, vinyl tris alkoxysilane, alkyl maleic acid monoester, alkyl fumaric acid monoester, acrylonitrile, methacrylonitrile, alkyl itaconic acid monoester, vinylidene chloride, vinyl acetate.

Examples include vinyl chloride. These can be used alone or in combination U of two or more.

Among these, hydroxyl groups, amide groups, carboxyl groups, or their salts (sodium salts, potassium Salts, ammonium salts, tertiary amine salts, etc.) are preferred.

When a crosslinked structure is introduced into a methacrylate copolymer, N-methylol (meth)acrylamide is used as a monomer that imparts the crosslinked structure.

N-alkoxymethyl (meth)acrylamide.

Glycidyl (meth)acrylamide, (meth)acrylic acid, 2-hydroxyethyl (meth)acrylate, etc., which have functional groups such as N-medylol group, N-alkoxymethyl group, epoxy group, carboxyl group, water ili group, etc. is preferably used. These can be used alone or in combination of two or more. When using two types of monomers, the functional groups should be a combination of, for example, a medillol group and a hydroxyl group, an alkoxymethyl group and a hydroxyl group, a medillol group and a carboxyl group, a glycidyl group and a hydroxyl group, a glycidyl group and a carboxyl group, etc. Good. The precursor methacrylate copolymer having two or more types of functional groups is a self-crosslinking type polymer. A precursor methacrylate copolymer having one kind of functional group can be used in combination with one having a group that reacts with the functional group to introduce a crosslinked structure. For example, it is preferable to use a crosslinking agent such as a methylolated melamine resin, an epoxy compound, an aziridine compound, or a polyvalent metal compound. The amount of crosslinking agent is 1 to 30% of the total solid content of the primer layer.
% by weight, more preferably 5 to 15% by weight.

A single layer of easily adhesive primer is usually formed by applying a primer-forming coating liquid to at least one side of a polyester film and drying (curing) it; however, the coating liquid has primer-forming components dissolved or uniformly dispersed in an organic solvent. Alternatively, the primer-forming component may be dissolved or uniformly dispersed in an aqueous solvent. Of these, the latter is preferred.

The production of the methacrylate copolymer or the precursor methacrylate copolymer and the preparation of the coating liquid can be carried out by any known method. For example, to illustrate an emulsion polymerization method in an aqueous dispersion system, one polymerization of an emulsifying dispersant (a surfactant such as sodium dodecylbenzenesulfonate) and a water-soluble polymerization initiator (a peroxide such as ammonium persulfate) is carried out in ion-exchanged water. Approximately 10% of the predetermined amount of the monomer is added by adding an appropriate amount of accelerator (reducing agent such as sodium acid sulfite) and stirring at a predetermined temperature (e.g., 50 to 90°C) and a predetermined stirring speed.
50% by weight, and once polymerization has started, the addition is interrupted for a short time, the remaining monomers are added at a constant rate, and the emulsion polymerization is carried out for several hours under the same conditions. Aqueous dispersions of copolymers can be prepared. In this case, the addition period of the surfactant used in the reaction is preferably 5% by weight or less, more preferably 1 to 2% by weight, based on the copolymerization component base. In this way, fine particles having an average particle size of 0.2 μm or less can be obtained. In addition, if necessary,
Molecular weight regulators (mercaptans), dispersion aids (polymer protective colloids such as polyvinyl alcohol and hydroxymethyl cellulose), etc. may be added.

In addition, applications of high molecular weight surfactants in place of the above-mentioned low molecular weight surfactants.2 Applications of reactive surfactants.

A production method using so-called soap-free polymerization, which does not contain a surfactant, may also be adopted. The molecular weight of the methacrylate copolymer (thermoplastic type) or precursor methacrylate copolymer (thermosetting type) produced by such a method is 10,000 to 2,000,000, and more preferably 200,000 to 1,500,000. It is preferable. In addition, for water-based coating liquids [7, water-based (precursor)]
A methacrylate copolymer is used, but a necessary amount of surfactant such as an anionic surfactant, cationic surfactant, or nonionic surfactant is added to improve the dispersibility of the copolymer. It is preferable. As such a surfactant, the surface tension of the aqueous coating liquid is 40 dyne, cm.
Preferably, those that can be reduced to the following and promote spreading into the polyester film are used, such as polyoxyethylene alkylphenyl ether, polyoxyethylene fatty acid ester, glycerin fatty acid ester, fatty acid metal soap, and alkyl sulfate.

Examples include alkyl sulfonates, alkyl sulfosuccinates, quaternary ammonium chloride salts, and alkylamine hydrochlorides. In addition (within a range that does not eliminate the effects of the present invention, for example, antistatic agents, ultraviolet absorbers, etc.)
Pigments, organic fillers.

Additives such as inorganic fillers, lubricants, and antiblocking agents can be mixed.

The coating liquid, particularly the aqueous coating liquid, may be applied to the polyester film in a normal coating process, that is, in a process in which the polyester film that has been stretched and heat-set is coated separately from the film manufacturing process.

However, this process tends to trap dirt, dust, etc., and it is desirable to apply the coating in a clean atmosphere for advanced products such as magnetic tapes and floppy disks. From this point of view, coating during the polyester film manufacturing process is preferable. In particular, it is preferable to apply an aqueous coating liquid to one or both sides of the polyester film before the crystal orientation is completed during this step. Here, the polyester film before crystal orientation is completed is an unstretched film obtained by thermally melting the polymer and forming it into a film as it is; A uniaxially stretched film that is oriented in either direction; and a film that is oriented by low-magnification stretching in both the vertical and horizontal directions (before finally being re-stretched in the vertical or horizontal direction to complete oriented crystallization) (2-wheel stretched film), etc. The solid content concentration of the coating liquid is usually 30% by weight or less, more preferably 10% by weight or less. The coating amount is preferably 0.5 to 20 g, more preferably 1 to 10 g per 1 Trt of the running film.

Any known coating method can be used as the coating method.

For example, roll coating method, gravure coating method, roll plush method, spray coating method, air knife coating method,
It is preferable to apply an impregnation method, a curtain coating method, etc. alone or in combination.

A polyester film coated with an aqueous coating solution before crystal orientation is dried and stretched.

This leads to processes such as heat fixation. For example, vertically coated with coating liquid.
The axially stretched polyester film is guided into a stenter, where it is laterally stretched and heat set. During this time, the coating solution dries and hardens) to form a continuous film on the film. Drying is preferably carried out before or during stretching.

Oriented crystallization conditions of polyester film, e.g. stretching,
Conditions such as heat fixation can be carried out under conditions conventionally accumulated in the industry.

The transparent and easily adhesive polynisdel film of the present invention has a small haze value of 3% or less when sieved to a total film thickness of 75μ, has excellent transparency, and is moldable with cellophane ink, magnetic paint, diazo paint, and inorganic coating. It exhibits an extremely wide range of adhesive adhesion performance to various materials and metal vapor deposited materials. It is particularly useful as a base for diazo films (microfilms) due to its excellent transparency and adhesive properties for diazo paints.

<Example> The present invention will be further explained below with reference to Examples.

Note that "parts" in the examples mean "parts by weight."

Moreover, each characteristic of the film was measured by the following method.

1. Adhesion The following diazo photosensitive liquid was applied onto the primer-coated polyester film to a dry thickness of 3 μm, and then Scotzi Tape No. 600 (manufactured by 3M) was applied onto the diazo photosensitive layer.
A tape with a width of 19.4 mm and a length of 15 cm is adhered without air bubbles, and the top is smoothed and brought into close contact with a manual load roll as described in JIS C2701 (1975), and then cut out to the tape width. This sample was quickly peeled off with the polyester film facing upward, and the peeling status of the diazo sight layer was observed.

Most of the diazo layer has been transferred to adhesive tape. × Half of the diazo layer remains on the polyester film. Δ All of the diazo layer remains on the polyester film. ○ Diazo photosensitive liquid> Binder cellulose acetate -Dobbrate 80 parts Diazo compound Daito Kagaku DH-3008F4 4 parts Coupling agent Daito Kagaku Grounder l)
5 parts Znα2 o,
1 part thia g urea 0.1 part P-chlorobenpine sulfone go o, i part M
E K 200 parts Toluene IOO part Cycliclosanone 200 parts 2, Blocking polyester film coated with primer Combine the pieces, cut into 10cm x 15cm squares, and add 55
6KMcm2 for 17 hours in an atmosphere of °CX88%RH
Then, the peel strength of this 10 part m width is measured. The peeling speed at this time was 100 mm/min.

3. Film transparency Po1c Hazemeter manufactured by Nippon Precision Optics viJ
Measured with 5EP-H3-01.

Examples 1 to 6 and Comparative Examples 1 to 3 Intrinsic viscosity measured in O-chlorophenol at 25°C [
0.65 polyethylene terephthalate (containing lubricant) was melt-extruded onto a rotating cooling drum maintained at 20°C to obtain an unstretched film with a thickness of 950 μm, and then 3
．． After stretching 5 times, an aqueous coating solution containing 90 parts of the resin component shown in Table 1 and 10 parts of a nonionic surfactant (polyoxyethylene nonylphenyl ether) was applied to both sides of the uniaxially stretched film by a kiss coating method. Subsequently, the film was stretched 3.9 times in the transverse direction at 105°C and further heat-treated at 210'C to obtain a polyester film coated with primer on both sides and having a thickness of 75 μm.

The average coating amount at this time was 50 mg/rd in terms of solid content.

The transparency, blocking properties, and adhesion properties of this film are
Shown in the table.

Table 1 shows that the primer-coated polyester film of the present invention has excellent adhesion to diazo paint, high transparency, and excellent blocking resistance, while the film of the comparative example has poor adhesion. It's obvious.

Example 7 Adding resin components to water-based coating liquids/ERA/KonAA/HEMA
=27/63/f? Completely the same method as in Example 1 except that 77 parts of methacrylate copolymer of /4, 10 parts of medirolled melamine resin (Sumitex Resin 3) and 3 parts of its catalyst (Sumitex Accelerator ACX) were used. A primer coated polyester film was obtained. This film had excellent adhesion to diazo paint and excellent transparency.

Claims (1)

[Claims] 1. At least one side of the polyester film contains methyl methacrylate (A) and ethyl methacrylate (B).
) and a vinyl monomer (C) copolymerizable with these, and their quantitative ratios satisfy the following formulas (1) and (2) [A]/[B]≦1...(1) 0. 75≦(1.5[A]+[B])/([A]+[B]
]+[C])≦1.22...(2) [In the formula, [A] is the mol% of component (A) in the polymer [B] is the mol% of component (B) in the polymer [C ] is the mol% of component (C) in the polymer. ] A transparent easily adhesive polyester film comprising an easily adhesive primer layer made of a methacrylate copolymer that satisfies the following. 2. The transparent easily adhesive polyester film according to claim 1, wherein the methacrylate copolymer has a crosslinked structure.