JPS59176042A - Easily adhesive biaxial stretched 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 The present invention relates to a biaxially oriented polyester film which has a specific coating layer on one side and has excellent secondary processability.

More specifically, the present invention relates to a biaxially oriented polyester film having good adhesive properties and having a coating F- made of a specific chloroprene resin and a specific polyester resin on at least one side of the polyester film.

Biaxially oriented polyester film, especially biaxially oriented polyethylene terephthalate film, has good transparency, dimensional stability,
Excellent IC properties such as mechanical properties, heat resistance, electrical properties, gas barrier properties, and chemical resistance, packaging materials, electrical insulation materials, metal vapor deposition materials, photosensitive materials using silver salts, diazo compounds, photosensitive resins, etc. It is also recommended for use as a base material for materials, electrophotographic materials, magnetic recording materials, etc.

For these uses, stretched polyester films are required to have adhesive properties. For example, in packaging materials (adhesion with printing inks and laminating materials), with photosensitive materials such as pyratin and polyvinyl Adhesiveness with a photosensitive pot using a binder such as alcohol, adhesion with a shade metal for metal vapor deposition materials, and adhesion with a magnetic layer for magnetic recording materials are required.

Methods for improving the seamability of biaxially oriented polyester films include copolymerization of specific polyester-forming components, methods using compositions containing specific resins, flame treatment, corona discharge treatment, plasma discharge treatment. Surface treatment methods such as ultraviolet irradiation treatment, chemical treatment using specific organic compounds or inorganic compounds, and the like are known. but,
Methods using combinations, compositions, and surface treatments may change their adhesion properties over time, may only adhere to specific objects, or may have high adhesion strength or may have adhesive properties. This method is not necessarily satisfactory for the applications described in .

In view of the above, at present, the film is put into practical use by applying an appropriate coating agent as an undercoat agent to the film depending on the application. However, in general, coating agents that have adhesive properties for biaxially oriented polyester films do not
In particular, it has poor adhesion with water-soluble resins such as polyvinyl alcohol, and conversely, coating agents that have adhesive properties with surface agents often have the disadvantage of poor adhesion with biaxially stretched polyester films. .

Furthermore, even if a coating agent has good adhesion to both a biaxially oriented polyester film and a specific surface material, it may not necessarily have good adhesion to a wide variety of surface materials. Even if the coating agent has good adhesion to the polyester film and surface material, the wettability of the coating agent to the polyester film may be poor, making it impossible to apply uniformly, or handling of films with a coating layer due to charging properties. Problems often arise in secondary processability, such as reduced workability and poor applicability when applying the surface layer material.

These problems are caused by the fact that the coating agent used is not suitable for occupational safety and health.
Organic solvent solution type is not used due to pollution, resource saving, energy saving, etc. (This is also due to various restrictions on making it water soluble or water dispersible type.

For example, water-soluble or water-dispersible polyester resins containing sulfonic acid groups have good coatability and adhesion to polyester films, and chargeability of coated films, but they have poor adhesion to certain surface materials. However, water-dispersible chloroprene resin has low coating properties (hereinafter referred to as adhesion properties) between the coating layer and the polyester film or between the coating layers (hereinafter referred to as adhesion properties) due to moisture absorption. It's bad.

However, the present inventors found that the coating agent containing this polyester resin and chloroprene resin has good coating properties and adhesion to polyester film, and that the coating agent containing this coating layer has good coating properties and adhesion to the polyester film. The present invention was based on the discovery that polyvinyl alcohol, which is difficult to adhere to, can be applied to various surface materials and has good adhesion.

In other words, the present invention consists of a polyester film containing polyethylene terephthalate as a main component (one side of which is coated with a water-soluble or water-dispersible polyester resin containing a water-dispersible chloroglene resin and a sulfo/acid base). This invention relates to a biaxially oriented polyester film.

The polyester film constituting the substrate of the present invention is a polyethylene terephthalate film in which 90 mol% or more of its constituent units are catethylene terephthalate.

The water-soluble or water-dispersible polyester resin (hereinafter abbreviated as polyester resin) having a sulfonic acid base used in the present invention includes the following:
No., Tokukai Akira! ;0-g3'197, Tokukai Sho! ;0-/
2/33A issue, JP-A-52-/! ;! A'l.

It is possible to use polyesters known in the art, such as No. 1, or polyesters similar thereto.

For example, dicarboxylic acid components of polyester include terephthalic acid, inophthalic acid, and inophthalic acid, as examples of aromatic dicarboxylic acids.
Examples of aliphatic/carboxylic acids include adipic acid, azelaic acid, sebacic acid and their ester-forming derivatives; Examples of carboxylic acids include oxybenzoic acid and its ester-forming derivatives.

Further, as glycol components of polyester, aliphatic, alicyclic, aromatic diols, etc. can be used, and examples thereof include ethylene glycol, /, couptanediol, diethylene glycol, triethylene glycol, /p, '
L-cyclohexane dimetatool, P-xylene diol, etc. are used, and examples of poly(oxyalkylene) glycols include so-called polyethylene glycol, polypropylene glycol, polytetramethylene glycol,
etc. are used.

As the polyester, not only the saturated linear polyester consisting of the above-mentioned ester-forming component, but also polyester consisting of a compound having an ester-forming component of trivalent or higher valence, or polyester having a reactive unsaturated group may be used.

A polyester having a sulfonate group can be produced using a compound having a sulfonate group that can be a polyester component together with the polynisder-forming component described above.

Examples of compounds having a sulfonic acid group include metal salts of sulfinophthalic acid, sulfoprephthalic acid, t-sulfonaphthalene-λ, 7-dicarboxylic acid and ester-forming derivatives thereof. Examples of metals in metal salts include:
Lithium, sodium, potassium, magnesium, etc. are preferred. Among these, a very preferred compound is 3-nodiosulfoinophthalic acid or sodiosulfodimethylisophthalate.

Another method for introducing sulfonic acid groups into polyester is to sulfonate the unsaturated groups of polyester containing an ester-forming aliphatic unsaturated compound as a copolymerization component with a sulfonating agent such as sodium bisulfite or sodium metabisulfite. It is also possible to exemplify the method of

The amount of aromatic dicarboxylic acid in the dicarboxylic acid component of the polyester resin is preferably in the range of SO molar head to 100 molar head. This is to increase the softening point of the polyester resin and improve its adhesion.

The sulfonic acid base in the polyester resin must be present in an amount necessary to make the resin water-soluble or water-dispersible. It is preferable to use within the range.

If the amount of sulfonic acid base is less than λ molar concentration, the water solubility and the water dispersibility will be insufficient. This is because if the amount of sulfonic acid base is more than 20 moles, the water resistance of the undercoat Jg after application will be poor, and the moisture-absorbing carbon films will stick to each other, resulting in poor JP quality.

Water-dispersible chloroprene resin C used in the crushing invention
(abbreviated as Coprene resin), edited by Kambara et al., "Revised new edition of the sole rubber: / Dobutsuku", pages 13g to 1,
2g/page, published by Breakfast Shoten, Showa I1, 1939///, or a method similar thereto may be used. Specifically, chlorogrene latex is available from DuPont or Showa Fuzoren Co., Ltd., Opsin (trade name), and Denka Kagaku Kogyo Co., Ltd. offers Denka chloroprene (trade name).
Chloroprene pomopolymer k) or copolymer commercially available as Skygrain Latex (trade name) from Toyo Soda Kogyo Co., Ltd. can be used.

In the case of a water-dispersible resin, the particle size of the water-dispersed particles is Sμ or less, preferably /μ or less, and more preferably 0.
/μ or less. When the particle size is large, there are problems such as agglomeration of particles is likely to occur during the coating process, and the transparency and gloss of the film are poor. Furthermore, if it is necessary to reduce the thickness of the coating layer, it is necessary to reduce the particle size accordingly.

The ratio of chloroprene resin to the total amount of polyester resin and chloroprene resin in the coating layer is preferably from 30% by weight to 99% by weight as a solid amount! rOT
E i% to 9SN amount head. If the proportion of chloroprene resin is small, the adhesion to surface materials such as polyvinyl alcohol will decrease, and since there is a large amount of polyester resin, it will tend to stick due to moisture absorption.If the proportion of polyester resin is small, The coating properties and adhesion of the coating agent to the polyester film are reduced.

Methods for applying chloroprene resin and polyester resin include a method in which a polyester film is previously coated with a polyester resin and then a chloroprene resin is applied, and a method in which a chloroprene resin and a polyester resin are blended and applied.

An example of an apparatus for applying a coating agent to a polyester film is "Coating Method" by Yuji Harasaki, published by Maki Shoten, 79, 79.
Examples include a reverse coater, a gravure coater, a rod coater, an air doctor coater, etc. shown in the October issue, but are not limited to these.

When to apply coating angle 11 to polyester film,
This may be before biaxial stretching, after biaxial stretching, or just before applying the P4 material. Particularly preferably, the coating agent is applied to a thinly stretched polyester film by the yellow roll stretching method, as exemplified by Tokko Sho Gu/-g Gua No. The stretching direction is a method of stretching in the placement direction and heat treating (hereinafter referred to as coating stretching method).If the coating stretching method is used, it is possible to dry the coating layer at the same time as stretching, and the coating layer is stretched. By doing so, the coating thickness can be reduced, and a wide laminated film can be obtained, which is difficult to achieve using methods other than coating stretchability.

It is also possible to subject the polyester film before the coating treatment to surface treatment such as corona discharge treatment 12 to improve the applicability and adhesion of the coating agent to the polyester film. Furthermore, by subjecting the biaxially stretched polyester film of the present invention to surface treatment such as corona discharge treatment, the adhesiveness to the surface layer material can be further improved.

The thickness of the coating layer of biaxially stretched polyester film Muhi is:
The range is preferably from 0.07μ to Sμ, more preferably from 0.0/μ to /μ. The thickness of the coating layer is o
If the thickness of the coating layer is less than 3μ, it will be difficult to apply it uniformly, resulting in uneven coating or insufficient adhesion in various applications.If the thickness of the coating layer exceeds 3μ,
The films tend to stick to each other, and the stiffness of the film becomes low compared to its overall thickness.

The coating layer of the biaxially stretched polyester film of the present invention includes:
Contains adhesion improvers, spreadability improvers, antifoaming agents, ultraviolet absorbers, antioxidants, antistatic agents, lubricants, inorganic fine particles, dyes, normal phase, etc. as necessary. Good too.

Furthermore, since the coating agent uses water as a medium, water-soluble resins such as gelatin, cellulose resin, polyether, silicone resin, epoxy resin, vinyl resin, horse/tan resin, and polyamide resin may be used in the coating layer. It can also contain a water-dispersible resin.

A crosslinking agent commonly used for crosslinking chloroprene resin to improve the adhesion of the coating layer, 4-aqueous property, 1-side solvent property, mechanical strength, etc., as well as general methylolated or alkylolated urea threads. , resins such as melamine, acrylamide thread, polyamide thread, epoxy compounds,
An aqueous solution or aqueous dispersion of block polyinocyanate or the like may also be used.

The thickness of the biaxially stretched polyester film of the present invention is Sμ
It is used as SOOμ.

The biaxially oriented polyester film of the present invention has the same adhesion properties as above to surface materials at moderate temperatures, and can be used for packaging materials, photosensitive materials, 5Jpg:'ZJ:', Shigito, Baiko photographic materials, When used in combination as a base material for magnetic recording materials, etc., it is particularly useful in applications using water-soluble resins such as poly, vinyl alcohol, and gelatin as a binder.

The present invention will be explained below with reference to Examples. In addition, the evaluation during implementation:1 will be based on the method described below.

/, 1 The applicability when applying a coating agent to a short polynisdel film was evaluated based on the following criteria.

○: Can be applied uniformly, causing no practical problems.

/K: Poor wettability, and some staining is observed on the coated surface.

×: Poor wettability (repels coating agent).

Transparency The transparency was evaluated based on the following criteria by the degree of haze using an integrating sphere type light transmittance classification device or by visual observation.

○: There is no practical problem.

△: There are uses that pose problems in practical use.

×: Not practically usable.

The adhesion between the base polyester film and the coating agent layer of the biaxially oriented polyester film provided with the coating layer of the present invention, and the adhesion between the biaxially oriented polyester film of the present invention and the surface layer materials shown in Table 2 are as follows: It was evaluated using the following method.

A cellotape manufactured by Nichiban Co., Ltd. with a width/gmm is applied to the coating layer of the film to a length of 7G1rL to prevent air bubbles, and a constant load is applied thereto using a 3 kg manual load roll.

The film was fixed, one end of the cellophane tape was connected to a soog weight, and the weight was allowed to fall naturally over a distance of 1 lscnL, and then a peel test was started in every θ° direction to evaluate the contact layer 1 (L).

Adhesion was evaluated using the following 5-level criteria.

3 or more is a practical range.

S: No peeling at all on the cellophane tape surface.

G: Less than 10% peels off from the cellophane tape surface. Practically speaking, it is not a problem (it can be used) if it is higher than the exponent.

3: 70 to 30% of the part peels off to the cellophane tape side.

, 2:! ; The portion above the θ ratio peels off to the cellophane tape side.

/: Completely peeled off to the cellophane tape side.

Adhesion The adhesion (blocking) test was carried out by overlapping the polyester film surface and the coated surface or the coated surfaces together, and heating at 20°C.
℃ or 0℃, the load is! ;Og/crA or 10o
g/ct/r for 20 hours. The evaluation criterion is a method of visually observing what percentage of the total area of the film is occupied by the adhered portion.

Comparative example/ A box of various coating agents of the second gen was applied to a biaxially stretched polyethylene terephthalate film with a thickness of 30 μm, and
It was applied with a rod and dried for 2 minutes at 0°C. The J-warness of this coating layer was approximately 0.Aμ. Two I! , lI+
As shown in Table 1, the adhesion between the stretched polyethylene terephthalate film and the coating agent was poor (biaxially stretched film 1;
It has been found that ethylene terephthalate film cannot be put to practical use as it is.

Comparison f, 'i+, 1 jζ・SOμ 24ζ11 stretched polyethylene terephthalate film from Showa I Obren Co., Ltd.); (Dispersible Chloroprene It Fat 4, Opsin 7 A; I enjoyed it and applied it with a rod. However, the applicability of the agent was extremely poor, and this -
! Until i, it was not possible to put it into practical use.

Comparative Example 3 Instead of neoprene 7kO (trade name) with a ratio of 15%
i:+The plate part was the same as that of Comparative Example v1 except that Neoprene g Dako A (trade name), a water-dispersible chloroprene rubber manufactured by Wa Neobrene Co., Ltd., was used. However, the coating properties of the coating agent were extremely poor, and it could not be put to practical use as it was.

Comparative Example: Finetex E8-A7θ (trade name), a water-dispersible polyester resin manufactured by Dainippon Ink and Chemicals, was applied at a concentration of 70% by weight to a biaxially stretched polyethylene terephthalate film with a thickness of 30 μm using a +g rod. The coating properties of the coating agent on the biaxially stretched polyethylene terephthalate film were extremely good.The thickness of this coating layer was approximately
, λμ. However, the evaluation result of the adhesion of this film was poor. Incidentally, it has been found that when a large amount of film is coated, the film is wound up into a roll, and stored in a normal room, both ends and the surface layer are highly sticky and tend to stick due to moisture absorption. Comparative Example 1: Various coating agents listed in Table 2 were applied to the coating layer surface of this film.
It was applied in the same manner as above and the adhesion was evaluated. As shown in Table 1, the adhesion of this film was quite poor to all three types of polyvinyl alcohol coating agents. That is, this film had poor adhesion (adhesive only to a specific coating agent), and could not be put to practical use as it was.

Example 1 Finetex B5-470C (trade name) 20, a water-dispersible polyester resin manufactured by Dainippon Ink and Chemicals, was applied to a biaxially stretched polyethylene terephthalate film having a thickness of SOμ.
parts (solid weight) and Showa Neoprene's water-dispersible chloroprene resin neoprene 7!;0 (trade name) go parts (
The concentration of the solid content (weight) of the aqueous dispersion is +3
It was applied with a rod of 100 ml and dried for 2 minutes at goC. The coating properties of the coating agent on the biaxially stretched polyethylene terephthalate film were good. The thickness of the coating layer of this film was about 7.2 microns.

The coating layer surface of this film was coated with various coating agents shown in Table 2 at a concentration of 3% by weight using a +3 rod, and dried for a minute at 0.degree. The thickness of this coating layer is approximately 0. It was Aμ.

The adhesion between various coating agents and the biaxially oriented polyester film of the present invention is good as shown in Table 1, and can be put to practical use.

Example 2 Example/neoprene? '! The procedure was carried out in the same manner as in Example 1, except that Neoprene g xi The coating and properties were good.The adhesion between the various coating agents shown in Table 2 and the biaxially oriented polyester film of the present invention was good as shown in Table 1, and could be used for practical purposes. It is.

Example 3 Intrinsic viscosity 0. A! of polyethylene terephthalate 2
g, , S-°C and extruded onto a cooling drum at 60°C to form a film. This film was stretched 3.3 times in the longitudinal direction with a roll at about 93°C to a thickness of about /g! It was made into an iμ film. In this film, a fluorosurfactant Megafac F-//A (trade name) O, S parts (solid weight) manufactured by Inu Nippon Ink Kagaku Kogyo Co., Ltd. was added to the coating agent of Example/. It was applied at a weight of 10% by weight. This film 7
The film was stretched 3.7 times in the transverse direction at 10°C, and heat treated under tension at 22 parts°C. The biaxially stretched polyester film thus obtained had a polyethylene terephthalate film RA of about soμ, a coating layer of about θ, and a cog μ. The uniformity of the coating layer of this biaxially stretched polyester film,
M, transparency, and adhesion were good, and the adhesion with the coating agents shown in Table 2 was also evaluated in the same manner as the four sides/, and as shown in Table 1, it was good. , this film can be put to practical use.

Claims (1)

[Claims] (1) An easily adhesive biaxially stretched polyester film made of polyethylene terephthalate as a main component, coated with a water-dispersible chloroprene resin and a water-soluble or water-dispersible polyester resin containing a sulfonic acid group on at least one side. Polyester film.