JPS61228956A - Easily adhesive polyester film and manufacture thereof - 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 Field of the Invention The present invention relates to an easily adhesive polyester film and a method for producing the same, and more particularly to an easily adhesive polyester film provided with a single layer of primer that is not dissolved by organic solvents and provides easy adhesive properties. This invention relates to a polyester film and its manufacturing method.

PRIOR ART It is known to melt-extrude and form films from heat-resistant polyesters, such as polyethylene terephthalate or its copolymers, polyethylene naphthalate or its copolymers, or blends of these with small proportions of other resins. be. It is also known that the resulting biaxially stretched and heat-set polyester film has better heat resistance, gas barrier properties, electrical properties, and chemical resistance than films made of other resins. However, since the surface of the polyester film is highly crystal oriented, the surface has high cohesiveness and poor receptivity to adhesives, ink, etc. Therefore, for example, a synthetic resin layer is added to the surface of the polyester film. In order to strengthen the adhesion between the two, the surface of the film is activated by corona discharge treatment, ultraviolet irradiation treatment, plasma treatment, or flame treatment, and then the synthetic resin coating film is coated. Applied.

However, although these methods of activating the film surface are expected to improve adhesion to the coating material layer by increasing secondary bonding force due to wetting, the activity decreases over time. Therefore, these means for activating the surface of the fill 4 are not necessarily satisfactory.

As another method for increasing the receptivity of the polyester film surface, an etching method has been proposed in which the surface is swollen or partially dissolved with a woodcutter's chemical. These are acids on the film surface.

The surface of the film is etched by contacting with chemicals such as alkali, amine aqueous solution, trichloroacetic acid, or phenols, and the crystal orientation near the surface is decomposed, #dissolved, and relaxed, and at the same time, the cohesiveness is reduced and the binder resin is removed. It is intended to improve the adhesion of the film and the layer provided thereon, for example, synthetic resin jI! The adhesion of the lower back layer becomes strong. However, some of the chemicals used in this method are harmful and may be dangerous to handle, and there is a risk that volatile substances from the chemicals may be released into the atmosphere. There are various disadvantages in practical painting, such as the need to be careful about

As a method similar to this method K11l, one layer of primer (undercoat layer) is provided on the surface of the film in advance, a thin surface layer different from the base film is formed, and then a desired layer is formed.
For example, there is a method of coating with a synthetic resin layer. When forming the undercoat layer, 111 fabric treatment is usually performed in a process different from the polyester film forming process. However, we cannot maintain the delicate quality of highly processed film products such as audio magnetic tape, video magnetic tape, computer magnetic tape, floppy disks, X* photographic film, printing photographic film, and diazo microfilm. Even if an easily adhesive surface is successfully formed, if the resulting film has surface defects caused by dust, it cannot be used as a base film for these applications, but in this separate process, are prone to this drawback.

Therefore, it is desirable to perform the undercoating process in an atmosphere as free from dust as possible. There is a polyester film forming process that satisfies these conditions, and if undercoating is performed in this process, it will be possible to obtain a product that can be fully used for the above-mentioned advanced film processed products.

On the other hand, in the conventional technology, the method of modifying the polyester film surface to an easily adhesive surface by primer treatment is as follows.
In many cases, this has been achieved by coating the surface layer of the film with a composition dissolved in an organic solvent. If such a method is carried out during film production, it may contaminate the surrounding environment with the fugitive organic solvent, resulting in unfavorable safety and hygiene conditions. The use of organic solvents should be kept to a minimum as much as possible since they have an adverse effect on the A-membrane process. Therefore Jl
! When performing an in-line undercoating process in a wrong step, it is preferable to use a composition using water as a solvent from the viewpoints of process, economy, and safety.

Therefore, many primer compositions using water as a solvent have been proposed, and in particular, many proposals have been made for aqueous solutions or dispersions of polyurethane or polyester. For example, Japanese Patent Publication No. 46-10193 discloses the use of polyurethane having solvent resistance to 7 setone and water dispersibility.

However, these primer compositions swell or dissolve in solvents used in magnetic coatings, such as methyl ethyl ketone, cyclohexane, detrahydrocufuran, etc., and have poor solvent resistance. When a magnetic paint is applied on such a single layer of primer, the primer layer and magnetic layer are mixed, which not only reduces the adhesion effect of the primer layer, but also causes streaks to appear on the surface of the coated layer, making it difficult to maintain a good quality. Unable to obtain a coated surface. As recording densities have increased in recent years, magnetic layers have tended to become thinner. In particular, floppy disks are rapidly becoming thinner, and the current has dropped to about 1μ. When the Kia layer becomes thinner in this manner, the flow streaks generated on the surface of the magnetic layer become even stronger, making it difficult to obtain a good magnetic surface.

Object of the invention The object of the invention is to apply various coatings applied to polyester films, such as cellophane inks, a-air paints, gelatin compositions, offset inks, electronic 4-tone toners, chemical matte paints, diazo maternity, heat-sealable Easy adhesion achieved by coating a single layer of a primer that has excellent adhesion to coating compositions, inorganic film-forming substances, etc., and has solvent resistance that does not cause mud removal streaks when applying these coatings. Our purpose is to provide polynisder film. Another object of the present invention is to provide a preferred method for producing such an easily adhesive polyester film.

Structure of the Invention According to the present invention, the following objects are achieved: 1. An aqueous coating solution containing an aqueous polyurethane having a carboxylic acid group on at least one side of a polyester film and an aqueous aziridine compound having two or more imine groups; an easily adhesive polyester film obtained by coating and heating and curing; and 26. an aqueous polyurethane having carbo/acid bases on at least one side of the polyester film before completion of crystal orientation and two or more imine groups; An aqueous coating liquid containing an aqueous aziridine compound having 311! cloth, then dry,
Stretch.

This is achieved by a method for producing an easily adhesive polyester film, which is characterized by subjecting the film to heat treatment to eliminate crystal orientation.

In the present invention, 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 phthalate, and polybutylene terephthalate.

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

The polyester film of the present invention is produced by melt-extruding such a saturated polyester resin, forming it into a film by a conventional method, and subjecting it to oriented crystallization and heat treatment crystallization. This polyester film is crystal-oriented to such an extent that the heat of fusion of the crystals measured with a scanner calorific value needle in a nitrogen stream (at a heating rate of 10°C/min) usually exhibits a value of 4 d/J/min or more. preferable.

In the present invention, a polyester film before completion of crystal orientation refers to an unstretched film obtained by thermally melting the polymer and forming it into a film as it is; an unstretched film oriented in either the vertical direction or the horizontal direction. uniaxially stretched film; furthermore, a film that has been stretched and oriented at a low magnification in two directions, the vertical direction and the horizontal direction (IIk Biaxially stretched film before finally being re-stretched in the vertical or horizontal direction to achieve oriented crystallization) film), etc.

The aqueous coating solution used in the present invention contains an aqueous polyurethane having a carboxylic acid group and an aziridine compound having 21 or more imine groups. This water-based poly 9
Rhettane has increased affinity for water by a carboxylic acid group, and the carboxylic acid group is usually introduced during or after polyurethane synthesis.

For example, when synthesizing polyurethane, one of the polyhydroxy compounds
As a method, a carboxylic acid group-containing polyhuman mixture compound is used, or a hydroxyl group-containing carboxylic acid or an amine 7 group-containing carboxylic acid is reacted with the incyanate group of a polyurethane having unreacted incyanate groups, and then the reaction product is stirred at high speed. It can be introduced by adding it to an alkaline aqueous solution and neutralizing it.

Sodium hydroxide is an alkaline aqueous solution.

It is preferable to use an aqueous solution of potassium hydroxide, ammonia, amine, etc., but ammonia, in which the alkali does not remain in the coating film, and amine, which volatilizes under drying conditions, are particularly preferable. The amount of carboxylic acid base is preferably 5 to 15% by weight.

If the proportion of the carboxylic acid base is too small, the water affinity of the polyurethane will be insufficient and the coating liquid will become harsh, and if it is too large, the inherent bone properties of the polyurethane will be impaired, which is not preferable. Such aqueous polyurethane forms a stable aqueous dispersion or aqueous solution using a dispersion aid if desired.

Examples of polyhydroxy compounds used in the synthesis of polyurethane include polyethylene glycol and polypropylene glycol. Polyethylene propylene glycol, bo1notetramethylene glycol, hexamebovine rangel glycol, tetramethylene glycol, II5''''bentanediol, diethylene glycol, triethylene glycol, polycabrolactone.

Polyhexamethylene 7dipate, polyhexamethylene sepacate, polytetramethylene adipate, polytetramethylene sebacate.

Examples include trimethylolf, bread, trinochlorethane, pentaerythritol, glycerin, and the like.

Examples of the polyincyanate compound include hexamethylene diisocyanate, diphenylmethane diisocyanate, tolylene diisocyanate, inphorone diisocyanate, an adduct of tolylene diisocyanate and trimethylene propane, an adduct of hexamethylene diisocyanate and trimethymylethane, etc. can be mentioned.

Examples of carboxylic acid-containing polyols include
Rubropionic acid, dimethylalbutyric acid, dimethylvaleric acid, trimellitic acid bis(ethylene glycol) ester, etc. may be mentioned. Examples of the amino group-containing carboxylic acid include β-7 minoprobion modified, r-aminobutyric acid, and p-7 minobenzoic acid. Furthermore, examples of the hydroxyl group-containing carboxylic acid include β-hydroxypropionic acid, r-human axybutyric acid, p-(2-human mixyethyl)benzoic acid, and malic acid. Synthesis of polyurethane using these compounds is
It can be synthesized by a conventionally well-known method.

As an aziridine compound having an imine group of 211m or more, for example (where n is an integer of 1 to 10) (where n is an integer of 1 to 10 (where n is an integer of 2 to 6)) (where n is an integer of 2 to 6), is an integer from 1 to 4] NS-ノ■ \.ノ0g NS%C/ 00H.

N\c7N 08m (However, n is an integer from 2 to 8 N\P/ (However, n is a !1 number from 1 to 6) 01) CM, 0COCH, CM, N]) 1
．． CCH,CC)i,0COC)i,CH,N,:]
-CH,0COCH,CH,Nku4 cH,ococ鴇CruNro1(OCH,C
CH,0COC)I,CH,NICM,0COCH,C
Examples include H, N:J, etc. The aziridine compound is preferably water-soluble, but if desired, it can be processed using a dispersion aid.
It may also be an aqueous dispersion. These five 1,6-
Hexamethylene diethylene urea is particularly preferred in terms of water solubility.

The aqueous coating liquid of the present invention may be a water bath liquid or an aqueous dispersion, but is not particularly limited. The ratio of the aqueous polyurethane having a carboxylic acid group to the aziridine compound having two or more imine groups is preferably 1 to 40 parts by weight, more preferably 1 to 20 parts by weight, to 100 parts by weight of the former. If the ratio of the aziridine compound is too high, the adhesion performance of the undercoat layer will be reduced, and if it is too low, the solvent resistance will be lowered, resulting in a coating surface that is easy to roll when the coating is applied, which is the objective of the present invention. It's undesirable because you're being harassed.

The aqueous coating liquid is made by dissolving or dispersing the above two components in an aqueous medium, but it is also possible to add a necessary amount of a surfactant such as Vc7=on surfactant or nonionic surfactant. can. As such a surfactant, one that can lower the surface tension of the aqueous coating solution to 40 dyn·71 or less and promote wetting to the polyester film is preferable.
For example, polyoxyethylene alkyl phenyl ether,
Polyoxyethylene-fatty acid ester, nrubitan fatty acid ester, glycerin fatty acid ester, fat deposit 31
1 soap, furkyl sulfate, furkyl sulfonate, furkyl sulfo/% phosphate, quaternary ammonium chloride, alkylamine hydrochloride, and the like.

Furthermore, in the range Mfl that does not eliminate the effects of the present invention, for example, antistatic agents, *external radiation absorbers, pigments, organic fillers,
Other additives such as inorganic fillers, lubricants, anticooking agents, etc. can be mixed.

Water-based to polyester film]! ! The coating may be applied in a normal coating process, that is, in a process of coating a biaxially stretched and heat-set polyester film separately from the film manufacturing process. However, this process tends to introduce dirt and dust, so it is desirable to apply the coating in a clean atmosphere for advanced products such as magnetic tapes and floppy disks. Coating during the polyester film manufacturing process is preferable from the viewpoint of bending. 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. At that time, water-based 1
! 1. The fixed concentration of the cloth solution is usually below 30 gravimetric quantum,
More preferably, it is 101% or less. The amount of coating is 0.5 to 20. V, 1-1 for refreshing
0Ii is preferred.

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

For example, a-le coat method, gravure coat method, o-le crush method, spray coat, air knife coat, impregnation method, curtain coat method, etc. may be applied alone or in combination.

The polyester film coated with the aqueous coating solution is dried and subjected to processes such as stretching and heat setting. For example, a longitudinally oriented polyester film coated with an aqueous coating solution is laterally stretched and heat-set by being rolled through a stenter 9. During this time, the coating solution dries and further undergoes a crosslinking reaction, forming a continuous film on the film. Heat for the crosslinking reaction is usually supplied by heat during stretching or heat setting. This may be done by heating at 200° C. for about 10 seconds, at 150° C. for about 1 minute, at 120° C. for about 15 minutes, at 220° C. for about 8 seconds, or heating under stricter conditions. Also, the drying time of the coating liquid is 10
0℃ for about 5 seconds, 110℃ for about 5 seconds, 90℃ for about 20 seconds.
Just heat it for a second. It may also be air-dried.

Conditions for orientation crystallization of the polyester film, such as stretching, heat setting, etc., can be carried out under conditions conventionally accumulated in the art.

Effects of the Invention The thus obtained polyester film having a single layer of primer is effective against extremely harsh paints such as printer inks, magnetic paints, gelatin compositions, electrophotographic toner compositions, and chemical matte paints. shows high adhesion,
and methyl ethyl ketone, toluene, ethyl acetate, butyl acetate, ethanol, dioxane.

Shows excellent solvent resistance to organic solvents such as tetrahydrofuran, cyclohexanone, and silica hexane.

Millet Examples Hereinafter, the present invention will be further explained with reference to Examples. In addition, "part" in an example means "E East quantity part". Moreover, each characteristic of the film was measured by the following method.

1. Apply the evaluation paint to the adhesive primer-treated polynisdel film, dry at 80°C for 1 minute, and then dry at 60°C for 24 hours.
The coating was rolled for 2 hours and then rolled coated to an average coating thickness of 2 μm. The resulting coated film is abraded with an RCA abrasion tester (RCA Co., Ltd.) K at a head load of 50 g, and the number of abrasions until holes are formed on the coated surface is used as a measure of adhesion.

[Adjustment of paint for evaluation]

Nitrocellulose R8I/2 as lacquer thinner for paints
(Flakes containing isopropanol 251: Daicel-
[manufactured by Bayer AG] was dissolved, a 40wt*jl solution was prepared by ILI, and 43.9 parts of the liquid was drained, followed by 32.5 parts of polynisder resin (Desmofuenna 1700, manufactured by Bayer AG), and 2.60 parts of silium dioxide magnetic powder. 9 Soybean oil and fat as a dispersant and wetting agent a! 1 part, 0.5 part, and 0.8 part of squalene (shark liver oil), respectively, were placed in a ball mill. Methyl ethyl ketone (hereinafter abbreviated as MEK)/cyclohexanone/toluene = 3/4/3
Further, 282s of the mixed solution consisting of (weight ratio) is further mixed and sufficiently pulverized to form a mother liquor paint (45 wt%). To 50 parts of this mother liquor, 48 parts of the addition reaction product of trimethylolbucuban and toluleine diisocyanate (
Coronate L (manufactured by Nippon Polyurethane Industry ■) and 6.25 parts of butyl acetate were added to give a final solid concentration of 42.75v.
Obtain t% of magnetic material for evaluation.

2. Solvent-resistant ply - Tetrahytomifuran is applied to the surface of the treated polyester film using a dropper - IIll (approximately 0.02
ec) Drop, place Nicase on top of the sono, and add 100#
The weight is moved through the gauze at a speed of about 1 ooom/min. The following judgments were made based on the surface changes of the primers using JII m micrographs taken at 400x magnification for those not treated with tetrahtomifuran and those treated with tetrahtomifuran.

Those with almost no primer: Example 1 Aqueous polyurethane dispersion containing carvone r117mine base (Toyo Polymer ■ back, trade name: Merci-585) 80
(as a non-volatile component), polyoxyethylene nonyl phenyl ether [manufactured by NOF ■, product name: NS-24
0110 parts and 10 parts of hexamethylene diethylene urea (Sogo Yakuhin Kogyo ■W, a product name: HDU) were diluted with ion-exchanged water to prepare an aqueous coating solution with a solid content concentration of 2% by weight.

This coating liquid was applied to a biaxially oriented polyethylene terephthalate film (by kiss coating method) and then heat treated in a drying zone at 140° C. for 45 seconds to obtain a primer-coated polyester film with an average coating weight of 50 dries/rrt.

The film had sufficient adhesion to the magnetic paint for evaluation, and it was possible to form a good coated surface without running streaks. The results are summarized in Table IK.

Example 2 Borie chlorine terephthalate (contains lubricant) with an intrinsic viscosity of 0.65 measured in 0-licIc1 phenol at 25°C
was melted and extruded onto a rotating drum maintained at 20°C to a thickness of 9.
An unstretched film of 50 μm was obtained, and then 3
．． After stretching 5 times, an aqueous coating solution identical to the aqueous coating solution used in Example 1 was coated on both sides of the axially stretched film using the kiss coating method. ~/d.Continued to add 10 films.
The film was stretched 3.9 times in the transverse direction at 5°C, and then filled with hot stones at 210°C to obtain a biaxially oriented polyester film coated with primer on both sides and having a thickness of 75 μm. Table 1 shows the characteristics of this film.
Shown below.

Comparative Example 1 The biaxially stretched Borier terephthalate film used in Example 1 was evaluated without being coated. The results are shown in Table 1.

Comparative Example 2 FJ was applied under exactly the same conditions as in Example 1 except that hexamethylene diethylene urea was not added to the aqueous coating solution &-Good.
14 ml of the solution was applied to a biaxially stretched polyester terephthalate film in the same manner as in Example 1. Table 1 shows the properties of the coated film obtained.

Comparative Example 3 The aqueous coating solution prepared in Comparative Example 2 in an amount of 114 m was applied to polybicylene terephthalate 2-yl A under the conditions of Example 20. The properties of the coated film obtained are shown in Table IK.

Claims (1)

[Scope of Claims] 1. Obtained by applying an aqueous coating solution containing an aqueous polyurethane having a carboxylic acid group and an aziridine compound having two or more imine groups to at least one side of a polyester film, and curing with heating. Easy adhesive polyester film. 2. The easily adhesive polyester film according to claim 1, wherein the carboxylic acid base of the aqueous polyurethane is a carboxylic acid amine base. 3. An aqueous coating solution containing an aqueous polyurethane having a carboxylic acid group and an aziridine compound having two or more imine groups is applied to at least one side of the polyester film before crystal orientation is completed, and then drying, stretching, and heat treatment are performed. 1. A method for producing an easily adhesive polyester film, the method comprising completing the crystal orientation by applying a polyester film. 4. The manufacturing method according to claim 3, wherein the carboxylic acid base of the aqueous polyurethane is a carboxylic acid amine base.