JPH0699578B2 - Easy-adhesive polyester film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to an easily-adhesive polyester film, more specifically, for example, chemical mat paint, offset ink, U
The present invention relates to a polyester film having excellent adhesiveness to V ink, diazo paint, magnetic paint, electrophotographic toner and other paints, inks and toners.

<Prior art> Polyester film, especially biaxially oriented film of polyethylene terephthalate, has excellent mechanical properties, heat resistance or chemical resistance, and therefore magnetic tape, photographic film, packaging film, capacitor metallizing film, electrical As a material for insulating films, OHP films, etc., the demand for them has been growing remarkably recently. However,
Since the polyester film has crystal orientation, it has high surface cohesion and poor adhesion to various paints.

Therefore, in order to improve the surface property of the polyester film, corona treatment, plasma treatment or flame treatment is used. However, these means have the drawback that their performance deteriorates over time. A method of overcoming this drawback is drug treatment. However, there are practical disadvantages such as the toxicity of this drug and the pollution of the environment due to the vaporization of its vapor.

As another means, there is known a method in which a biaxially stretched polyester film is coated with an easily adhesive coating agent to form a primer layer. However, this method also involves safety and hygiene problems such as deterioration of the environment due to volatilization of the solvent, and the risk of frequent occurrence of surface defects due to adhesion of dust because the coating atmosphere is dirty.

Therefore, if this primer treatment is carried out in the process of forming a polyester film using a water-based coating agent, less dust adheres in a clean environment and there is no fear of explosion or environmental deterioration due to the water-based coating agent. It is also advantageous in terms of film performance, economics, and safety.

Due to these advantages, it has been proposed to use a water-soluble or water-dispersible polyurethane or copolyester resin as the primer. However, the above-mentioned primer layer has the drawbacks that the films block each other due to changes in temperature and humidity during storage, and the adhesiveness to diazo paint and UV ink is insufficient.

<Object of the Present Invention> An object of the present invention is to provide a polyester film having excellent adhesiveness to various paints, inks, toners, etc., particularly diazo paints, UV inks and the like.

<Structure / Effect of the Invention> According to the present invention, according to the present invention, an acrylic copolymer resin 70 in which (A) a carboxyl group-containing monomer is copolymerized on at least one surface of 1 to 15 mol% ~ 98% by weight and (B)
It is achieved by an easily adhesive polyester film having a crosslinked primer layer using 2 to 30% by weight of a polyglycidyl amine compound.

In the present invention, the polyester 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, polybutylene terephthalate, poly (1,4-cyclohexylene dimethylene terephthalate) and polyethylene-2,6-phthalene dicarboxylate.
These copolymers or blends of these with small proportions of other resins are also included. The polyester may contain a small amount of inorganic or organic fine particles in order to improve slipperiness. Examples of such fine particles include inorganic fillers such as titanium oxide, calcium carbonate, silica, barium sulfate and silicone, and organic fillers such as acrylic, benzoguanamine, Teflon and epoxy. Further, it may contain an easily-adhesive property such as PEG and sodium dodecylbenzenesulfonate and an antistatic agent. This polyester is melt-extruded into a film by a conventional method,
Further, oriented polyester crystallization by biaxial stretching in the longitudinal and transverse directions and crystallization by heat treatment give the polyester film of the present invention.

In the present invention, (A) an acrylic copolymer resin obtained by copolymerizing 1 to 15 mol% of a carboxyl group-containing monomer constituting the primer layer (hereinafter referred to as a carboxyl group-containing acrylic copolymer resin) means a carboxyl group. The second-order transition point is 20 to 95, which is obtained by copolymerizing 1 to 15 mol% of the contained monomers.
The main target is a carboxyl group-containing (meth) acrylic acid ester resin at ℃. Such a resin includes a carboxyl group-containing monomer such as (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, styrenesulfonic acid, and salts thereof (sodium salt, potassium salt,
Ammonium salt, tertiary amine salt, etc.) and other copolymerizable monomers such as alkyl (meth) acrylate (wherein the alkyl group is a methyl group, ethyl group, n-propyl group, isopropyl group, n- Butyl group, isobutyl group, t
-Butyl group, 2-ethylhexyl group, cyclohexyl group, etc.); hydroxy-containing monomers such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate; (meth) acrylamide, N-alkyl (meth) acrylamide And N, N-dialkyl (meth)
Acrylamide (wherein alkyl group is methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group,
Isobutyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group, etc.), N-alkoxymethyl (meth) acrylamide and N, N-dialkoxymethyl (meth) acrylamide (where the alkoxy group is methoxy group, ethoxy group) Group, butoxy group, isobutoxy group, etc.), N-methylol (meth) acrylamide, N, N-dimethylol (meth) acrylamide, N-phenyl (meth) acrylamide, and other amide group-containing monomers; such as glycidyl (meth) acrylate Epoxy group-containing monomer; Acid anhydride monomer such as maleic anhydride, itaconic anhydride, etc .; vinyl isocyanate, allyl isocyanate, styrene,
Obtained by double or more copolymerization with monomers such as vinyl methyl ether, vinyl trialkoxycin, alkyl maleic acid monoester, acrylonitrile, methacrylonitrile, vinylidene chloride, ethylene, propylene, vinyl chloride, vinyl acetate, acrylonitrile and butadiene. To be Methyl methacrylate (MMA) and ethyl acrylate (EA) are preferred as the main components of the monomers constituting this copolymer. Particularly, the MMA / EA ratio is preferably in the range of 0.5 to 3 in terms of molar ratio. Further, it is preferably in the range of 0.7 to 2. The total amount of MMA and EA is 50-9 in total mol%.
8% is preferable and 80 to 96% is more preferable. The amount of the carboxyl group-containing monomer as an essential component is 1 to
It is 15 mol%. It is preferably in the range of 1 to 10 mol%. When the amount of the carboxyl group-containing monomer is less than 1 mol%, the reaction efficiency with the crosslinking agent is low and the solvent resistance is insufficient. On the other hand, if it exceeds 15 mol%, the moisture resistance deteriorates, which is not preferable.

When the second transition point of such a resin is less than 20 ° C., the blocking phenomenon between the films occurs due to the tackiness of the primer layer. On the other hand, if it is higher than 95, the primer layer is hard and brittle, so that there is a drawback that the adhesiveness to the polyester film is deteriorated. The second transition point is preferably 30 to 70 ° C,
Furthermore, 40 to 70 ° C is preferable.

As the polyglycidylamine compound (B) constituting the primer layer in the present invention, glycidylamine (tetrafunctional) can be preferably mentioned.

The (B) polyglycidylamine compound has excellent reactivity with the (A) carboxyl group-containing acrylic copolymer resin,
It has an advantage that a sufficiently crosslinked primer layer can be formed without using a reaction promoting compound. This is in marked contrast to other polyglycidyl compounds that require the use of reaction promoting compounds. However, in the present invention, a reaction accelerator may be used to accelerate the reaction.

Examples of the compound (reaction accelerating compound) that promotes the reaction between the carboxyl group (carboxyl group and its base) of the acrylic copolymer resin (A) and the glycidyl group include a compound containing a tertiary amino group and a nitrogen-containing ring structure. Examples thereof include compounds and salts thereof, quaternary ammonium salt compounds, and the like. As a specific example, tri-n-butylamine,
Examples thereof include dimethylaminobenzene, 2,4,6-tris (dimethylaminomethyl) phenol, 2-methylimidazole, 1,8-diazobicyclo (5,4,0) undecene-7 and tetramethylammonium chloride.

The polymerization percentage of (A) a carboxyl group-containing acrylic copolymer resin and (B) a polyglycidylamine compound in the primer is 70 to 98% for (A) and 2 to 30% for (B). The primer layer in the present invention can be formed by applying a coating liquid containing the components for forming the layer, preferably an aqueous liquid, onto a polyester film, followed by drying and heat curing.

The coating liquid is preferably an aqueous liquid such as an aqueous solution or a water emulsion liquid. The aqueous liquid may contain a small amount of an organic solvent for stabilizing the dispersion of solid components. This aqueous primer coating solution is obtained by dissolving or dispersing the above-mentioned two components as essential components in an aqueous medium, and a catalyst and a wetting agent are added if necessary. Examples of the wetting agent include anionic, cationic and nonionic surfactants. It is preferable that this surfactant makes the surface tension of the aqueous liquid 40 dyne / cm or less and accelerates the wetting of the polyester film. For example, polyoxyethylene alkyl phenyl ether, polyoxyethylene-fatty acid ester, sorbitan fatty acid ester, glycerin fatty acid ester, fatty acid metal soap, alkyl sulfonate, quaternary amine salt, betaine type surfactant and the like can be mentioned. Further, an antistatic agent, an ultraviolet absorber, a pigment, an organic filler, an inorganic filler, a lubricant, an antiblocking agent, etc. may be used in combination unless the object of the present invention is impaired.

The step of applying the aqueous primer coating solution is preferably performed on the surface of the substrate immediately after the polymer is melt extruded and cast, or immediately after the polymer is stretched in one of the longitudinal and transverse directions. As a normally performed step, a primer layer is applied on a uniaxial film stretched in the machine direction, then stretched laterally while heating, and the film is heat-set at a high temperature and the thermosetting of the primer layer is completed. As a method for applying the primer layer on the polyester film, a known method can be applied. 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 brush method, etc. can be applied. The concentration of the applied coating liquid varies depending on the coating method, but is generally 0.5 to 5
It is 0% by weight. The coating amount is preferably 1 to 20 g / m ² in terms of wet amount.

The film of the present invention has excellent adhesiveness, and is particularly used for general industrial films such as chemical matte films, membranes, telephone cards, labels, microfilms, diazo films, OHP films and video tapes, audio tapes, computer tapes, floppy disks, etc. It is useful as a base material for magnetic tapes.

<Examples> The present invention will be described in detail below with reference to Examples. Various values in the specification are measured as follows. In addition, "parts" in the examples represents parts by weight.

(1) Adhesiveness A diazo photosensitive paint having the following composition is applied to the primer-coated polyester film by 6 μ (Dry).

[Evaluation paint] Cellulose acetate butyrate 70 parts DH-200BF4 (manufactured by Daito Kagaku) 9 parts SC-100 (manufactured by Daito Kagaku) 7 parts Citric acid 8 parts Acid 6 parts Next, this diazo photosensitive layer was developed with ammonia and then exposed. A cellophane tape is pressed onto the layer with a roller, and the humidity is controlled at 23 ° C for 16 hours, and then strongly peeled. Then, the diazo photosensitive layer is entirely left on the polyester film side. ◯ Half is peeled off. Δ All is peeled off.

(2) Blocking property A primer-coated polyester film is cut out in a size of 15 × 10 cm, and the primer surfaces are placed on top of each other and a load of 50 kg / cm ² is applied and held at 50 ° C. for 16 hours, after which peel strength is measured in the width direction of 10 cm. taking measurement.

Comparative Example 1 A lubricant-containing polyethylene terephthalate having an intrinsic viscosity of 0.61 of a polymer measured in ortho-chlorophenol at 25 ° C. was extruded from a T-die and electrostatically applied on a drum cooled to 40 ° C. while a thickness of 152 μm was measured. A stretched film was prepared, subsequently heated to 93 ° C. and stretched 3.6 times in the machine direction, and then a primer coating solution having the following composition was applied onto the uniaxially stretched film by a kiss coating method.

<Primer coating liquid composition> Acrylic copolymer resin 80 parts (48 mol% methyl methacrylate, 48 mol% ethyl acrylate, 4 mol% ammonium acrylate) 1,6-hexamethylene diethylene urea 5 parts Nonionic surfactant ( NOF NS-20, NOF CORPORATION
8.5) 15 parts The wet application amount at this time was 5% × 3 g / m ² .

Then, the film was laterally stretched at 102 ° C. by a factor of 3.6 and then heat-treated at 223 ° C. to obtain a biaxially stretched (easy adhesive) polyester film having a thickness of 75 μm.

The performance of this film is shown in Table 1.

Example 1 A primer-coated polyester film was obtained in the same manner as in Comparative Example 1, except that glycidylamine (tetrafunctional) was used instead of 1,6-hexamethylenediethyleneurea in Comparative Example 1. The performance of this film is shown in Table 1.

Comparative Example 2 A primer solution was prepared by adding 10 parts of glycerol triglycidyl ether, 3 parts of 2,4,6-tris (dimethylaminomethyl) phenol and 15 parts of the nonionic surfactant of Comparative Example 1 to 72 parts of the acrylic resin of Comparative Example 1. Was prepared. A primer-coated polyester film was obtained in the same manner as in Comparative Example 1 except that this primer solution was used. The performance of this film is shown in Table 1.

Comparative Example 3 For comparison, Table 1 shows the performance of the polyester film not coated with any primer.

As is clear from Table 1, the primer-coated polyester film of the present invention has excellent adhesion and blocking properties, and is particularly useful as a polyester film for general industry.

Claims (1)

[Claims] 1. An acrylic copolymer resin having 70 to 98% by weight of (A) a carboxyl group-containing monomer copolymerized on 1 to 15 mol% of at least one side of a polyester film and (B).
An easily-adhesive polyester film having a crosslinked primer layer containing 2 to 30% by weight of a polyglycidylamine compound.