JPH0730188B2 - Easy-adhesive polyester film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention relates to an easily-adhesive polyester film, and more specifically, for example, a chemical mat paint, an offset ink,
The present invention relates to a polyester film having excellent adhesiveness to coating materials such as UV inks, diazo paints, magnetic paints, and electrophotographic toners, inks and toners.

<Prior Art> Polyester film, especially biaxially stretched film of polyethylene terephthalate, has excellent mechanical properties, heat resistance or chemical resistance, and therefore magnetic tape, photographic film, packaging film, metallized film for capacitors, electric film 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 properties 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 possibility of frequent occurrence of surface defects due to adhesion of dust because the coating atmosphere is dirty.

Therefore, if this primer treatment is performed during the film-forming process of the polyester film by using the water-based coating agent, dust adhesion is less 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 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 / Effects of the Invention> According to the present invention, according to the present invention, a primer in which (A) a hydroxyl group-containing acrylic copolymer resin is cross-linked with (B) a glycidylamine compound on at least one surface of a polyester film Achieved by an easy-adhesive polyester film characterized by having a layer.

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), polyethylene-2,6-phthalene dicarboxylate, and the like.
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 and barium sulfate, and organic fillers such as acrylic resin, silicone, benzoguanamine, Teflon and epoxy. Further, it may contain an easily-adhesive property and an antistatic agent such as polyethylene glycol (PEG) and dodecylbenzene sulfonic acid soda. The base film of the present invention can be obtained by melt-extruding this polyester by a conventional method to form a film, and further by crystallizing the polyester by orientation crystallization by biaxial stretching in the longitudinal and transverse directions and by heat treatment.

The (A) hydroxyl group-containing acrylic copolymer resin used for forming the primer layer in the present invention has a secondary transition point of 20 to
It is a hydroxyl group-containing (meth) acrylic acid ester resin at 95 ° C. This resin preferably has no free carboxyl groups. Such resins include hydroxyl group-containing monomers such as 2
-Hydroxyalkyl (meth) acrylates such as hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate and other copolymerizable monomers such as alkyl (meth) acrylates (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.); (meth) acrylamide, N-alkyl (meth)
Acrylamide or N, N-dialkyl (meth) acrylamide (wherein the alkyl group is a methyl group, an ethyl group, n
-Propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group), N-alkoxymethyl (meth) acrylamide and N, N-dialkoxymethyl (meth) acrylamide (Here, the alkoxy group includes methoxy group, ethoxy group, butoxy group, isobutoxy group, etc.), N-methylol (meth) acrylamide, N, N-dimethylol (meth) acrylamide, N-phenyl (meth) acrylamide and the like. Amide group-containing monomer; epoxy group-containing monomer such as glycidyl (meth) acrylate; vinyl isocyanate, allyl isocyanate, styrene,
It is obtained by copolymerizing two or more kinds of monomers such as vinyl methyl ether, alkyl maleic acid monoester, acrylonitrile, methacrylonitrile, vinylidene chloride, ethylene, propylene, vinyl chloride, vinyl acetate and butadiene. Methyl methacrylate (MMA) and ethyl acrylate (EA) are preferable as the main components of the monomers constituting this copolymer. Especially the MMA / EA ratio is 0.5-
It is preferably in the range of 3. Further, it is preferably in the range of 0.7 to 2. The total amount of MMA and EA is 5 in total mol%
0 to 98% is preferable, and 80 to 96% is more preferable. The amount of the hydroxyl group-containing monomer as an essential component is preferably 0.5 to 15 mol%. More preferably, it is 1 to 10 mol%.

When the second transition point of the resin is less than 20 ° C., the film-blocking phenomenon occurs due to the adhesiveness of the primer layer. On the other hand, when the temperature is higher than 95 ° C, the primer layer is hard and brittle, so that the adhesiveness to the polyester film is deteriorated. The second-order transition point is preferably 30 to 70 ° C, more preferably 40 to 70 ° C.

In the present invention, the compound (B) used for crosslinking the hydroxyl group-containing acrylic copolymer resin (A) is a glycidylamine compound. This glycidyl amine compound is a compound having at least one tertiary amino group and two or more glycidyl groups in one molecule, and for example, And the like are preferable. In addition to these compounds, a small amount of an aqueous solution of trimethylolpropane triglycidyl ether, glycerin triglycidyl ether, or the like or a water-dispersible polyglycidyl compound can be used together.
Further, a compound (reaction accelerating compound) that promotes the reaction between the hydroxyl group and the glycidyl group can be used, and examples of the compound include a tertiary amino group-containing compound, a compound having a nitrogen-containing ring structure and its salt, and quaternary ammonium. Salt compounds and the like can be mentioned. As a concrete example,
n-butylamine, dimethylaminobenzene, 2,4,6-
Examples thereof include tris (dimethylaminomethyl) phenol, 2-methylimidazole, 1,8-diazo-bicyclo (5,4,0) undecene-7 and tetramethylammonium chloride.

The weight% ratio of (A) hydroxyl group-containing acrylic copolymer resin and (B) glycidyl amine compound in the primer layer is 60-99% for component (A) and 1-40% for component (B). Preferably there is. A more preferred range is 70 for component (A).
.About.98% and the component (B) is 2 to 30%.

The primer layer in the present invention can be formed by applying a coating liquid, preferably an aqueous liquid, containing the components for forming the layer onto the 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 liquid is a dispersion in which the above two components are not dissolved as an essential component in an aqueous medium, but a catalyst and a leaking agent are added if necessary. The leaking agent includes 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 leakage of the polyester film. Examples thereof include 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. 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 method usually performed, a primer layer is applied on a uniaxial film stretched in the longitudinal direction,
Then, the film may be transversely stretched while being heated, and the film may be heat-set at a higher temperature, and the thermosetting of the primer layer may be completed. As a method of applying the primer layer on the polyester film, a known method can be applied. For example, the spray coating method, the ener knife method, the reverse coating method, the kiss coating method, the gravure coating method, the Meyer bar method, the roll brush method, etc. can be applied. The concentration of the coating liquid applied varies depending on the coating method, but is generally 0.5 to 50% by weight. 1 to 20 g / m ² wet coating amount
Is preferred.

The polyester film having the primer layer of the present invention has excellent adhesiveness, and in particular, it is a general industrial film such as a chemical matte film, a membrane, a telephone card, a label, a micro film, a diazo film, an OHP film and a video tape, an audio tape, a computer. It is useful as a base material for magnetic recording media such as tapes and floppy disks.

<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 Oxalic acid 6 parts Then, 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 peeled off ... △ All peeled off ... x.

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

Examples 1 to 3 A lubricant-containing polyethylene terephthalate having an intrinsic viscosity of 0.61 of a polymer measured in orthochlorophenol at 35 ° C. was extruded from a T-die, and electrostatically applied on a drum cooled to 40 ° C. while having a thickness of 152 μm. Was stretched in the machine direction by 3.6 times, and the primer coating solution having the above composition was applied onto the uniaxially stretched film by a kiss coating method.

<Primer coating liquid composition> Acrylic copolymer resin having the composition shown in Table 1 80 parts N, N, N ', N'-tetraglycidyl-m-xylenediamine 5 parts Nonionic surfactant (NOF Corporation ) Nonion NS-20
8.5) 15 parts The wet application amount at this time was 5% × 3 g / m ² .

After that, 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 (easily adhesive) polyester film having a thickness of 75 μm.

The performance of this film is shown in Table 2.

The abbreviations in the above table are as follows.

MMA; methyl methacrylate EA; ethyl acrylate NMAA; N-methylol acrylamide HEMA; 2-hydroxyethyl methacrylate MAA; methacrylamide Example 4 88 parts of the acrylic copolymer resin in Example 2 with Tetrad C5 manufactured by Mitsubishi Gas Chemical Company Department, Nagase Kasei Co., Ltd. DINACOR EX
A primer solution was prepared by adding 1 part of −313 and 6 parts of Nonion NS208.5 manufactured by NOF Corporation. A primer-coated polyester film was obtained in the same manner as in Example 1 except that this primer solution was used. The performance of this film is shown in Table 2.

Comparative Example 1 For comparison, Table 2 shows the performance of the polyester film not coated with any primer.

As is clear from Table 2, the primer-coated polyester film of the present invention has excellent adhesion and blocking resistance.

Claims (1)

[Claims] 1. An easily-adhesive polyester film having a primer layer obtained by crosslinking (A) a hydroxyl group-containing acrylic copolymer resin with (B) a glycidylamine compound on at least one side of the polyester film.