JP3028537B2 - Laminated film - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a thermoplastic resin laminated film excellent in water / oil repellency, antifouling property, non-adhesiveness, release property, substrate protection property and moisture resistance. More particularly, the present invention relates to a thermoplastic resin laminated film having excellent adhesion between layers and good durability.

[Prior art] Thermoplastic resin films such as polyester, polyamide, and polypropylene (particularly, polyester films such as polyethylene terephthalate) have excellent mechanical strength, heat resistance, chemical resistance, transparency, dimensional stability, and the like. As such, it is widely used in applications such as base films for magnetic tapes, insulating tapes, photographic films, tracing films, and films for food packaging. But,
These thermoplastic resin films are water- and oil-repellent, antifouling,
It is not always satisfactory in terms of non-adhesiveness, release properties, substrate protection properties, moisture resistance and the like.

On the other hand, fluorine-based resin films have most of the above-mentioned properties that are lacking in ordinary thermoplastic resin films,
Printing and laminating are extremely difficult. Therefore, a method is considered in which a fluororesin film is laminated with a thermoplastic resin film to ensure printability and laminating properties on the thermoplastic resin film side. However, it is not possible to obtain a high-quality laminated film by adopting the method. Therefore, as a means of increasing the lamination adhesiveness, a method of providing an anchor coat layer, a method of activating the surface of a thermoplastic resin film, and modifying a fluororesin to an extent capable of easily adhering to a thermoplastic resin film. (The properties of the fluororesin are significantly impaired by this modification). However, none of these methods is sufficient in cost and product characteristics.

[Problems to be Solved by the Invention] The present invention has been made in view of the above-mentioned circumstances, and its object is to provide water and oil repellency, antifouling property, non-adhesive property, mold release property, An object of the present invention is to provide a film in which a fluororesin layer is laminated, which is excellent in material protection and moisture resistance, and which can be manufactured with good productivity and at low cost.

[Means for Solving the Problems] The structure of the laminated film according to the present invention, which can solve the above problems, is based on a non-stretched or uniaxially stretched thermoplastic resin film containing a fluorine-containing polymer as a main component. The composition is a laminated film laminated, wherein the composition does not contain an aqueous polymer and a reactive low-molecular weight substance other than the fluorine-containing polymer, and the composition was laminated It has a gist in that it is heat-treated after uniaxial or biaxial stretching.

[Function] As described above, in the laminated film of the present invention, a non-stretched or uniaxially stretched thermoplastic resin film (hereinafter, sometimes referred to as a base film) contains a fluorine-containing polymer as a main component, The composition can be obtained by laminating a composition containing no molecule and a reactive low molecular weight substance (hereinafter, referred to as a fluorine-based resin composition), further uniaxially or biaxially stretching, and then performing heat treatment. Although the reason why the adhesion between the fluororesin composition layer and the base film is enhanced by specifying such requirements is not necessarily clarified, the following may be considered.

That is, in the conventional method of manufacturing a laminated film by laminating a fluororesin film on a base film, first the base film is biaxially stretched to secure physical properties, and then the surface is activated to improve the adhesion as described above. After the treatment, it is laminated with the fluororesin film. However, since a fluororesin film originally has a small surface energy and poor adhesion, it is not easy to increase the adhesion to the base film while maintaining the characteristics of the fluororesin. Further, since the base film that has been biaxially stretched has a high orientation due to stretching, and has a dense surface, even if the fluorine-based resin composition is applied to this surface, the base film may be finely recessed at the boundary surface. It cannot be expected to improve mechanical adhesion due to the effect of insertion. However, in an unstretched or uniaxially stretched film, an unoriented portion is left with respect to the biaxially stretched film, so that there is room for the fluorine-based resin composition to enter the surface thereof, so that the It is considered that a part of the fluororesin composition applied to the base film penetrates into the surface of the base film, and a wedge effect is exerted to enhance the adhesion. Then, when the laminated film is uniaxially or biaxially stretched, predetermined physical properties are given to the base film, and the physical properties are also improved. However, since the characteristics of the film-like fluororesin composition layer formed by lamination tend to be degraded due to internal strain accompanying stretching, heat treatment is performed after stretching to remove the internal strain of the fluororesin composition layer. At the same time, it is considered that by heat-setting the base film layer, the properties of both the base resin and the fluorine-based resin composition are stabilized, and a laminated film having excellent adhesion and physical properties is obtained.

There are various types of base films and fluororesin compositions used in the present invention, which are appropriately selected according to the application and required characteristics. Preferred examples are as follows.

First, as the base film, polyester film, polyamide film, polycarbonate film,
Polyphenylene sulfide film, polyether imide film, polyether sulfone film, polyolefin film, cellulose film, PVA film, acrylic film, polyvinyl chloride film and the like, among which the most commonly used Is a polyester film, a polyamide film, a polycarbonate film, a cellulosic film, or the like.

Examples of the fluorine-containing polymer as a main component of the fluorine-based resin composition include polyvinylidene fluoride, tetrafluoroethylene-propylene copolymer, vinylidene fluoride-hexafluoropropylene copolymer, tetrafluoroethylene, and hexafluoroethylene. And a copolymer of a fluoroolefin such as chlorotrifluoroethylene or vinylidene fluoride with an alkyl vinyl ether or another substituted vinyl ether. Specific examples of the alkyl vinyl ether and the substituted vinyl ether include, for example, methyl vinyl ether, isobutyl vinyl ether, hydroxybutyl vinyl ether, cyclohexyl vinyl ether, fluorovinyl ether, and glycidyl vinyl ether. Of course, other copolymerizable methacrylic acid or acrylic acid and derivatives thereof, vinyl esters such as vinyl acetate, styrene and the like may be used.

Further, as a particularly preferable fluorine-containing polymer in the present invention, for example, a polymer having a perfluoroalkyl group having 3 or more carbon atoms, preferably 6 to 21 is mentioned, and specific examples are represented by the following formulas (1) to (5). A polymer of an ethylenically unsaturated monomer having a perfluoroalkyl group as shown and a monomer and another ethylenically unsaturated monomer, for example, an ethylenically unsaturated acid ester of polyoxyalkylene glycol, hydroxy At least one selected from alkyl acrylate, glycidyl methacrylate, methacrylic acid, acrylamide, acrylate, acrylonitrile, vinyl acetate, methyl vinyl ether, and the like
And copolymers with various kinds of copolymerizable monomers. In particular, a copolymer with an ethylenically unsaturated monomer having a polyoxyalkylene chain is awarded as a preferred fluorine-containing polymer because of its excellent uniform adhesion and stain removal.

C _n F _{2n + 1} CHO−CH = CH ₂ (2) Further, compounds represented by the following formulas (a) to (e):
Polyurethanes obtained from tolylene diisocyanate, 2,6 tolylene diisocyanate, 4,4-diphenylmethane diisocyanate, trimethylolpropane tolylene diisocyanate, isophorone diisocyanate and hexamethylene diisocyanate are also one of the preferred fluorine-containing polymers. These copolymers may be used in combination with other glycols as a copolymer component, if necessary.

The fluorine-containing polymer preferably has a fluorine content of 10% by weight or more and a degree of polymerization of 100 or more in order to effectively utilize the excellent properties.

Also, these fluorine-containing polymers, if necessary,
Acrylic resin, polyurethane resin, polyester resin,
Blends epoxy resin, polyolefin resin, cellulose resin, vinyl ester resin, vinyl alcohol resin, rubber resin, silicone resin, polyamide resin, polyvinylidene chloride resin, polyvinyl chloride resin, etc. (excluding aqueous polymer) Or, as long as the properties of the fluorine-containing polymer are not impaired, colorants, antistatic agents, anti-blocking agents, lubricants using inorganic or organic particles, ultraviolet absorbers, deterioration inhibitors, etc. (Excluding reactive low molecular weight compounds).

In producing the laminated film of the present invention using the base film and the fluororesin composition, first, the thermoplastic resin as the base film material described above is dissolved in a suitable solvent, and the film is formed by a casting method or the like. After this film is stretched as it is or uniaxially stretched, a fluororesin composition is laminated and adhered to the surface thereof by the following method. Prior to this lamination, it is also effective to subject the surface of the base film to an adhesion improving treatment such as a corona discharge treatment or an ultraviolet irradiation treatment.

As a method of forming the fluororesin composition layer on the base film, the fluororesin composition is prepared by mixing the fluororesin composition with an emulsion or acetone, methyl ethyl ketone, dioxane, n-hexane, cyclohexanone, toluene, xylene, trichloroethylene, trichloroethane, perchloroethylene. Such as a solvent solution, a method of applying this to a base film, or dipping and then drying, or a method of laminating a base film by a coextrusion coating method, an extrusion lamination method, a dry lamination method, or the like,
Furthermore, a method of bonding by a hot melt bonding method or the like can be adopted, but the coating and drying method can provide the best adhesion. Preferred adhesion amount of fluorine-containing resin composition when employing a coating and drying method 0.003~20g / m ^2, more preferably in the range of 0.01 to 10 g / m ^2, fluorine-based resin composition is less than 0.003 g / m ² The effect of modification by lamination of materials is not sufficiently exhibited, while if it exceeds 20 g / m ² , the slipperiness of the laminated film becomes poor.

The thus obtained laminate is further uniaxially or biaxially stretched to enhance the physical properties of the base film layer, and then heat-treated to remove the internal stress of the fluorine-based resin layer and heat-fix the base film layer. It is possible to obtain a high-performance laminated film having both characteristics and characteristics of a fluororesin and having both adhered strongly. The stretching conditions at this time are not particularly limited, but the preferred stretching ratio is 2 in both the longitudinal and transverse directions.
The range is from 7 to 7, more preferably from 3 to 5 times. When an unstretched material is used as the base film, biaxial stretching is preferably performed after lamination of the fluororesin composition, and when a uniaxially stretched base film is used, the stretching direction of the base film after lamination is changed. It is desired that the base film is stretched in a direction orthogonal to the base film and finally the base film is biaxially stretched. However, this stretching does not exclude multi-stage stretching in both the vertical and horizontal directions.

The heat treatment performed after the stretching is intended mainly to remove the stress of the stretched fluororesin layer,
It is selected from the range of 0 to 250 ° C, preferably 180 to 230 ° C.

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to the following Examples.

In the following Examples, the adhesion between the base film and the fluororesin composition layer, the transferability of the coating layer (fluororesin composition layer), the surface energy and the antifouling property were evaluated by the following methods.

(Adhesion with Base Film) The coat layer was cross-cut into 100 cross-cuts, and after hand rubbing 20 times, the number of cross-cuts remaining in the coat layer was evaluated.

(Transfer resistance) Coated surface Fluorine resin coated surface and non-treated surface (3cm × 3c
m) and apply a load of 5 kg on the film at 40 ° C.
After leaving at × 90% RH for 72 hours, an aqueous ink was printed on the non-treated surface, and the appearance was observed. By this test, it is possible to know the degree of transfer of the fluororesin from the coated surface to the non-processed surface due to pressure (the printability of the non-processed surface will deteriorate if the transfer of the fluororesin occurs). The better the value, the better the transfer resistance.

A: Printed evenly B: Printed surface with fine repelling C: Printed surface with remarkably large repelling (Surface energy) From the contact angle of water and methylene iodide, DK. Owens et al. [J.Appl.Polym.Sci., Vol.13pp.1741-1747 (196
9)], the polar force component and the dispersion force component of the surface energy were calculated. This value is one evaluation criterion of stain resistance, and the smaller the sum of the two, the better the overall stain resistance.

(Anti-fouling property) 1 cc of heavy oil B was dropped on the resin film, left for 30 minutes, and then the heavy oil B was wiped off, and the degree of oil stain was evaluated using a gray scale for JIS contamination.

Example 1 Fluorine-containing polymer having the following monomer composition (degree of polymerization:
400, 10% concentration) [emulsifier: polyoxyethylene (40 mol%) cetyl ether].

On the other hand, polyethylene terephthalate was melt-extruded at 280 to 300 ° C. and then cooled with a cooling roll at 15 ° C. to a thickness of 300 μm.
m of unstretched polyester film was obtained. This unstretched polyester film was passed through a pair of rolls (temperature: 85 ° C.) having different peripheral speeds and stretched 3.3 times in the machine direction.

After applying the emulsion polymerization solution to the surface of the uniaxially stretched film by a kiss method, the coating was dried with hot air at 70 ° C. to form a coating layer made of a fluororesin composition.

This laminated film was stretched 3.5 times in the transverse direction at 100 ° C. and heat-set at 200 to 210 ° C. to obtain a biaxially stretched laminated film having a thickness of 30 μm (coating layer 0.2 μm).

Fluorine-containing emulsion polymerization in the fluorine-containing resin composition _{CH 2 = CHCOOCH 2 CH 2 C} n F 2n + 1 (n = 6~12 average 9) 60 mole% butyl acrylate 20 mol% of vinylidene chloride 20 mol% Example 2 Example 1 A biaxially stretched laminated film was obtained in the same manner as in Example 1 except that a resin solution having the following composition was used instead of the liquid. However, cyclohexanone / methyl isobutyl ketone (70/30) was used as the solvent, and the resin concentration was adjusted to 15%.

Fluorine-containing resin composition Terolafluoroethylene 70 mol% Cyclohexyl vinyl ether 15 mol% Hydroxy vinyl ether 5 mol% Ethyl vinyl ether 10 mol% Example 3 A fluorine-containing urethane resin prepared by the following method in place of the fluorine-containing resin in Example 1 A biaxially stretched laminated film was obtained in the same manner as in Example 1 except that an aqueous solution was used.

(Production method of fluorine-containing urethane resin aqueous solution) A perfluoroalkyl urethane compound obtained by reacting 2 mol of a perfluoroalkyl group-containing glycol, 1 mol of dimer acid diisocyanate, 3 mol of methylenebisdiisocyanate and 2 mol of diethanolamine represented by An aqueous solution (solid content 30%) was prepared.

Comparative Examples 1 to 3 Each of the fluorine-containing resin liquids used in Examples 1 to 3 was applied on a biaxially stretched polyester film so as to have the same coating layer thickness as in Example 1, and dried at 100 ° C. A laminated film was obtained.

Comparative Example 4 The laminated film obtained in Comparative Example 1 was heat-treated at 210 ° C. for 20 seconds without performing a stretching treatment to obtain a test film.

Comparative Example 5 A biaxially stretched polyester single-layer film was obtained in the same manner as in Example 1, except that the fluorine-containing resin layer was not laminated.

For each film obtained in the above Examples and Comparative Examples,
Adhesion between layers, transferability, surface energy and antifouling property were examined by the above-mentioned method.

 The results are collectively shown in Table 1.

From Table 1, the following can be considered.

It is a laminated film that satisfies the requirements of the present invention of Examples 1 to 3, has good interlayer adhesion, hardly any transfer of a coating layer, has low surface energy, and has excellent antifouling properties. Have been.

On the other hand, Comparative Examples 1 to 5 lack any of the prescribed requirements defined in the present invention, and have problems in some performance as described below.

Comparative Examples 1-3: Fluororesin resins were left as they were laminated, neither stretched nor heat-treated, and adhesion between the laminates, transfer resistance, antifouling properties, Very bad compared to the example film.

Comparative Example 4: After lamination of the fluororesin, only heat treatment was performed without stretching, and although the surface energy showed a low value, adhesion between the laminations, transfer resistance and antifouling properties were insufficient. It is.

Comparative Example 5: A biaxially stretched film of a polyester single layer, having very high surface energy and poor antifouling properties.

[Effects of the Invention] The present invention is constituted as described above, and is obtained by laminating a fluorine-containing polymer layer on a thermoplastic resin film in an unstretched state or stopped before a uniaxial stretching, and then uniaxially or biaxially. By stretching and heat-treating, the adhesion between the laminations can be remarkably increased, thereby fully exhibiting the characteristics of the thermoplastic resin layer and the fluorine-containing resin layer, and a high-performance laminated film that combines the characteristics of both resin films. Can be provided.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-60-192630 (JP, A) JP-A-2-27934 (JP, A) JP-A-59-176330 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) B32B 1/00-35/00

Claims (5)

(57) [Claims] 1. A laminated film obtained by laminating a composition containing a fluorine-containing polymer as a main component on an unstretched or uniaxially stretched thermoplastic resin film, and further performing a uniaxial or biaxial stretching and heat treatment. The fluorine-containing polymer is a copolymer of a fluoroolefin and an alkyl vinyl ether or another substituted vinyl ether.In the composition, an aqueous polymer other than the fluorine-containing polymer and a reactive low-molecular-weight polymer are included. A laminated film characterized by not being included. 2. A laminated film obtained by laminating a composition containing a fluorine-containing polymer as a main component on an unstretched or uniaxially stretched thermoplastic resin film, and further performing a uniaxial or biaxial stretching and heat treatment. The fluorine-containing polymer is a copolymer of an ethylenically unsaturated monomer having a perfluoroalkyl group having 6 to 21 carbon atoms and another ethylenically unsaturated monomer, and in the composition, Wherein the laminated film does not contain an aqueous polymer other than a fluorine-containing polymer and a reactive low-molecular-weight polymer. 3. A laminated film which is obtained by laminating a composition containing a fluorine-containing polymer as a main component on an unstretched or uniaxially stretched thermoplastic resin film, and further performing a uniaxial or biaxial stretching and heat treatment. In addition, the fluorine-containing polymer is at least one selected from the following formulas (a) to (e), 2,4 tolylene diisocyanate, 2,6 tolylene diisocyanate, 4,4-diphenylmethane diisocyanate, and trimethylol. Propane tolylene diisocyanate, isophorone diisocyanate, a polyurethane obtained from at least one selected from hexamethylene diisocyanate, A laminated film, characterized in that the composition does not contain an aqueous polymer and a reactive low molecular weight substance other than a fluorine-containing polymer. 4. The laminated film according to claim 1, wherein heat treatment after stretching is performed at 150 to 250 ° C. 5. The laminated film according to claim 1, wherein the thermoplastic resin film is a polyester film.