JPH0348497B2 - - Google Patents

Description

[Detailed description of the invention]

(a) Field of Industrial Application The present invention relates to an antistatic masking film comprising a plastic film support and a light-shielding release layer provided on one side thereof, and more specifically, to
The present invention relates to an antistatic type light-shielding masking film which is provided with a light-shielding peeling layer that is not sticky and has improved antistatic properties on one side of a light-transmitting plastic film support. (b) Prior Art A light-shielding masking film is made by providing a light-shielding release layer on a light-transmitting plastic film support, and can be peeled off by partially peeling off the release layer. Since the exposed portion is translucent, it is used in photoengraving and the like by taking advantage of this property. The characteristics required for a light-shielding masking film include: high strength of the release layer, good translucency of the plastic film support, excellent removability of the release layer, and the ability to remove the release layer with a cutter knife. Characteristics include: no lifting occurs in the non-peelable area even when a cut is made, the cut edge of the peeling layer with a cutter knife is sharp, excellent light-shielding properties, flexibility, and the ability to obtain precise photorealistic objects. In addition, in particular, it is necessary that the light-shielding masking film not be charged with electricity during production or use, and that dust and the like should not adhere to it, and that the surface should not be sticky. Therefore, recently the following have been proposed. That is, an antistatic light-shielding masking film has been proposed, which is formed by coating a nitrile rubber composition containing an ionic antistatic agent on a plastic support (Japanese Patent Application Laid-Open No. 108537/1983). The ionic antistatic agent used here is an anionic antistatic agent or a cationic antistatic agent, such as alkyl sulfonate, allyl sulfonate, alkyl sulfosuccinate ester salt, amine salt of sulfuric acid ester, phosphoric acid ester, etc. Examples include anionic antistatic agents such as ester salts and alkyl carboxylates, amphoteric antistatic agents such as cationic antistatic agents such as alkylamine salts, amidoamines or salts thereof, and esteramine quaternary ammonium salts. This light-shielding masking film is designed to prevent static electricity, and also prevents the viscosity of the nitrile rubber composition (coating liquid) containing an antistatic agent from increasing over time, making it easy to apply. It is made to be moisturized. An electrostatic recording material for plate making having a mask layer has been proposed, which is characterized in that a dielectric layer is provided on one side of a transparent support via a peelable conductive mask layer or a peeling layer (Japanese Patent Application Laid-Open No. 60-123847). Furthermore, a structure in which a low resistance layer is laminated on the transparent support is also disclosed, but the low resistance layer is made of a mixture of a resin that has good adhesion to the transparent support, an antistatic agent, or an antistatic resin. It is made by adding an antiblocking agent. Examples of the antistatic agent include polyethyleneimine hydrochloride, a copolymer of 2-acryloylethyltrimethylammonium chloride and vinylsulfone, poly(N-methylvinylpyridinium chloride), polyvinylbenzyltrimethylammonium chloride, and quaternized ammonium chloride. Examples include salt-acrylic copolymers and quaternized ammonium salt-epoxy resin copolymers. However, when such an antistatic agent is used, as described above, blocking occurs, so it is necessary to add an antiblocking agent. (c) Problems to be Solved by the Invention However, in the above method, the ionic antistatic agent is liquid at room temperature and not only bleeds onto the surface and becomes sticky, causing blocking, but also causes dyeing and staining in the release layer. The pigment is leached out, and this leached dye is
There is a problem in that the pigment transfers to the surface of the transparent plastic film support and deteriorates its transparency. In addition, if an ionic antistatic agent is used in solid form, the antistatic agent is ionic and has poor affinity with the resin component of the release layer. It bleeds onto the surface, resulting in a significant drop in adhesion, and when the release layer is cut with a cutter knife, it lifts, causing serious problems such as the cut edges of the release layer not being sharp, making it impossible to obtain a precise photographic object. It happens. On the other hand, in the above products, the antistatic agent has poor affinity with resins with good adhesive properties such as vinylidene chloride resin, and may bleed onto the surface and have a negative effect on adhesive properties, or prevent blocking unless an antiblocking agent is added. When an antiblocking agent is added in this way, there are problems such as a decrease in adhesive strength. (d) Means for Solving the Problems In order to solve the above problems, the present inventors have made extensive studies and found that the release layer provided on one side of the plastic film support has an electrically charged solid state at room temperature. Surprisingly, the inclusion of an antistatic agent, especially an antistatic agent consisting of glycerin stearate, not only does not cause problems such as stickiness or blocking, but also does not significantly affect the adhesion of the release layer. They have discovered that it is possible to appropriately adjust the adhesive force of the release layer and maintain a certain level of release properties, leading to the completion of the present invention. That is, the present invention is a light-shielding masking film comprising a release layer mainly made of thermoplastic plastic, rubber, or a mixture thereof on one side of a light-transmitting plastic film support, and the release layer has a temperature of room temperature. Contains a solid antistatic agent,
Further, the antistatic agent is a glycerin stearate ester. The present invention will be explained in detail below. The plastic film support used in the present invention may be either a stretched film or an unstretched film, as long as it has good translucency and flexibility. Typical examples of such plastic film supports include polyethylene terephthalate,
Examples include polyester films such as polybutylene terephthalate and polyoxybenzoate, polycarbonate films, and polypropylene films. Further, thermoplastic plastics used in the present invention include polyvinyl chloride, vinyl chloride resins such as vinyl chloride-vinyl acetate copolymers, nitrocellulose, polyacrylate resins, polyamide resins, polyacetal resins, polystyrene resins, Examples include resins selected from polyester resins and the like, but among these, those that are particularly compatible with the rubber described below, transparent, and non-sticky at room temperature are preferred, and from this point of view, vinyl chloride resins are most desirable. The vinyl chloride resin used is one that is compatible with the rubber described below and is not sticky at room temperature. Such vinyl chloride resin is usually a homopolymer or copolymer with a degree of polymerization of about 500 to 1000, and a preferred specific example thereof is vinyl chloride-vinyl acetate copolymer (vinyl chloride monomer
85 to 95% by weight, vinyl acetate 15 to 5% by weight), etc. Further, the rubber used in the present invention may be either synthetic rubber or natural rubber, and is appropriately selected from those that adhere to the plastic film support used. Among these, synthetic rubbers are preferred, and those with excellent adhesive properties such as nitrile rubber, urethane rubber, and acrylic rubber are particularly preferred. As the above-mentioned acrylic rubber, those having good adhesiveness and UV resistance are particularly preferably used. The acrylic esters constituting the acrylic rubber include alkyl esters (preferably,
Esters having 1 to 4 carbon atoms are preferred, and other components include acrylonitrile and the like. Specific examples of acrylic rubber include butyl acrylate-acrylonitrile copolymer,
Its composition ratio is preferably 85 to 90% by weight of butyl acrylate, 9.5 to 15% by weight of acrylonitrile, and 0.5 to 2% by weight of 2-hydroxyethyl methacrylate, and its molecular weight is 100,000 to 600,000 (based on polystyrene). The number average molecular weight measured by gel permeation chromatography is preferred. The mixing ratio of the above-mentioned thermoplastic plastic (A) and rubber (B) is usually in the range of 50 to 80% by weight of (B) based on the total solid content of (A+B), preferably 60 to 80% by weight.
A range of 70% by weight is desirable. If (B) is too small (less than 50% by weight), the adhesion to the plastic support will be poor and the release layer may peel off easily.On the other hand, if (B) exceeds 80% by weight, the characteristics of the rubber will be significantly affected. This is not preferable because the degree of elongation of the release layer becomes large and the work becomes difficult. In the present invention, light-shielding dyes and pigments are blended in order to impart light-shielding properties to the release layer, and such dyes and pigments are soluble in organic solvents and are compatible with the above-mentioned rubber and thermoplastic plastic. Dyes and pigments that are compatible with the mixed resin and have light-shielding properties are used, and dyes and pigments that are particularly stable against heat and ultraviolet rays and have little change in color tone are preferred. Further, the color tone and structure of the dye/pigment are not particularly limited. The blending ratio of the dye/pigment may be any amount sufficient to exhibit light-shielding properties, and is generally 0.5 to 10 parts by weight based on 100 parts by weight of the resin solid content in the mixed resin. Such light-blocking dyes and
Examples of the pigment include oil-soluble dyes, organic solvent-soluble dyes, metal complex dyes, and organic pigments. The release layer used in the present invention prevents dust adsorption, prevents stickiness on the surface of the release layer, and prevents light-shielding dyes and
An antistatic agent, which is solid at room temperature, is included to prevent the pigment from transferring onto the plastic film support. The present invention is characterized in that the antistatic agent is glycerin stearate. In this way, when glycerin stearate is used as an antistatic agent, blocking does not occur, so there is no need to add an antiblocking agent that adversely affects adhesion, and it does not significantly affect the adhesion of the release layer. preferred. In order to appropriately adjust the adhesive strength of the release layer and maintain a certain level of releasability, it is sufficient to adjust the proportions of glycerin stearate monoester, glycerin stearate diester, and glycerin stearate triester. be. In this case, polyoxyethylene stearyl ether is optionally used in combination with the glycerin stearate ester, depending on the type of thermoplastic plastic or rubber used. The preferred amount of the antistatic agent is sufficient to prevent the generation of static electricity, and is generally preferably 0.5 to 10% by weight based on the solid content in the release layer. If the amount is less than 0.5% by weight, the expected antistatic effect will not be obtained, while if it exceeds 10% by weight, it will have an adverse effect on the physical properties of the entire release layer, which is undesirable, and the particularly preferred amount is 1.0%.
A range of ~6.0% by weight is desirable. It is preferable that a matting agent is added to the release layer for the purpose of preventing light reflection. As the matting agent, particles having a matting ability (for example, hydrated amorphous silicon) having a particle size of 10 μm or less are used. The blending amount of the matting agent is about 0.5 to 3% by weight, preferably 0.75 to 3% by weight based on the resin content in the release layer.
It is about 2% by weight. If the blending amount is less than 0.5% by weight, there will be no matting effect, while if it exceeds 3% by weight, there will be a limit to the matting effect, and conversely, the harmful effect of the matting agent will be that the cutter knife blade will wear out faster and the light shielding effect will deteriorate. This is not preferable because it deteriorates the transparency of visible light and causes problems in layout work, etc. The antistatic light-shielding masking film of the present invention can be obtained by dissolving a resin composition made of thermoplastic plastic, rubber, light-shielding dye/pigment, etc. in a solvent such as acetone, methyl ethyl ketone, toluene, xylene, or a mixed solvent thereof. Furthermore, a composition obtained by mixing this with other ingredients is coated on one side of a plastic film support using, for example, a roll coater to form a release layer. Ru. (e) Effect The antistatic light-shielding masking film of the present invention uses an antistatic agent that is solid at room temperature,
In addition, since the antistatic agent is a glycerin stearate ester, it does not significantly affect the adhesion of the release layer, and the release layer does not become sticky, and the dye/pigment in the release layer does not ooze out. It has. In addition, the generation of static electricity is prevented by using glycerin stearate as an antistatic agent, and the ratio of glycerin stearate monoester, glycerin stearate diester, and glycerin stearate triester is By adjusting it, the adhesive force of the release layer can be appropriately adjusted and, moreover, it is possible to maintain a certain degree of releasability. (f) Examples Hereinafter, the present invention will be explained in detail based on Examples, but the present invention is not limited thereto. Example 1 A biaxially stretched polyethylene terephthalate film (thickness: 100 μm) was used as a translucent plastic film support. On the other hand, acrylic rubber (molecular weight approx. 10
10,000 parts by weight) and 90 parts by weight of vinyl chloride/vinyl acetate.
10 (weight ratio) and 60 parts by weight of copolymer (degree of polymerization 750) was dissolved in 450 parts by weight of methyl ethyl ketone, and a light-shielding dye, Spiron Orange 2RH (Hodogaya Chemical Co., Ltd.) was added to this solution. 4 parts by weight of glycerin stearate (82.4% by weight of mono-form, 11.5% by weight of di-form, 4.9% by weight of tri-form, 1.2% by weight of others), which is a nonionic antistatic agent that is solid at room temperature. Mix and dissolve 0.8 parts by weight of polyoxyethylene stearyl ether, which is also solid at room temperature.
This solution was used as a coating liquid. The thus obtained coating solution was applied onto one side of the polyethylene terephthalate film support using a roll coater, and dried in an oven for 2 minutes to form an orange-colored antistatic light-shielding product of the present invention with a total thickness of 125 μm. A sex masking film was obtained. The properties of the masking films thus obtained are shown in Tables 2 to 5. Example 2 A biaxially stretched polyethylene terephthalate film (thickness: 125 μm) was used as a transparent plastic film support. On the other hand, 35 parts by weight of acrylic rubber consisting of 12% by weight of acrylonitrile and 88% by weight of butyl acrylate, and 90/10 (weight ratio) of vinyl chloride/vinyl acetate.
65 parts by weight of the copolymer (degree of polymerization 800) was dissolved in 450 parts by weight of methyl ethyl ketone, and 4 parts by weight of Spiron Red GEH (manufactured by Hodogaya Chemical Industry Co., Ltd.), a light-shielding dye, was added to the solution, which was solid at room temperature. 2.5 parts by weight of glycerin stearate, an antistatic agent (45.4% by weight of mono-form, 38.7% by weight of di-form, 5.9% by weight of tri-form, 10% of others) and Carplex FPS-7 (Shionogi Co., Ltd.), a matting agent. 1 part by weight (manufactured by Yakuhin Co., Ltd.) was mixed, and this solution was used as a coating liquid. The coating liquid thus obtained was applied onto one side of the polyethylene terephthalate support using a roll coater to obtain an antistatic light-shielding masking film of the present invention having a total thickness of 150 μm, a red color, and a matte surface. The surface of the masking film thus obtained can be written on with a writing instrument such as a pencil or ballpoint pen before the peeling line is cut with a knife, and even when photographed with a plate-making camera, work using reflected light is necessary to prevent halation. is possible. Moreover, the characteristics of this masking film are as shown in Example 1.
It was the same. Experimental Example 1 (Peeling layer strength/peelability test) The antistatic light-shielding masking film obtained in Example 1 was used as a sample, and Competitor's product-1, Competitor's product-2, and Competitor's product-3 were used as comparative examples. was used. Each of the above samples was made into a size of 200 mm in length and 15 mm in width.
Each piece was cut out and exposed to ultraviolet light for 465 hours using an ultraviolet carbon fade meter. For each sample before and after UV irradiation, the plastic support side was adhered to a copper plate, and polyester adhesive tape (Nitsuto No. 31B) was attached to the release layer surface to serve as a reinforcing piece. layer strength) and 180 degree peeling (peelability). The results are shown in Tables 2 and 3, respectively. Test method (1) Tensile strength and elongation of release layer Test equipment Tensilon universal testing machine UTM (manufactured by Toyo Baldwin) Test conditions Temperature 24℃ Distance between fulcrums 100mm Tensile speed 200mm/min (2) Peelability of release layer (180 degree peeling) Test equipment Same as above Test conditions Temperature 24°C Peeling speed 300mm/min Experimental example 2 (Light transmittance test) Each plastic film was tested before and after the same ultraviolet irradiation as used in Experimental example 1. Regarding the support and release layer, the plastic film support was examined for its light transmittance, and the release layer was examined for its light blocking property. The results are shown in Table 4. Test method/Test device: Spectrophotometer UV 240 (manufactured by Shimadzu Corporation) - Test conditions: Temperature: 24°C As is clear from the results shown in Table 2, the antistatic, light-shielding masking film of the present invention is susceptible to deterioration due to ultraviolet rays, etc. It is resistant to UV irradiation, and its strength hardly changes even when exposed to ultraviolet irradiation. On the other hand, it can be seen that known light-shielding masking films are deteriorated by ultraviolet irradiation and become difficult to peel off, and even if they are peeled off, the release layer is brittle and has deteriorated to the extent that its properties cannot be measured. In addition, light-shielding masking films are usually used for 180° peeling.
Although a strength of 200 g/15 mm or more is required, it can be seen from the results in Table 3 that only the antistatic type light-shielding masking film of the present invention satisfies this strength. Furthermore, in the visible light of 600 nm, the plastic film support in the antistatic light-shielding masking film of the present invention is easier to see through than known ones, and the release layer has almost no light-shielding properties before and after irradiation with ultraviolet rays. That there is no change,
This is confirmed from the results in Table 4.

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[Table] * Test specimens of Competitor's Product 1, Competitor's Product 2, and Competitor's Product 3 could not be tested for the same reason stated in * in Table 2.

[Table] Experimental Example 3 (Comparison test of antistatic effect) The same sample used in Experimental Example 1, but before irradiation with ultraviolet rays, was used. Test method (1) Method according to surface leakage resistance JIS-L-1094 (1980 reference test 1). (2) Charge voltage, half-life, decay rate after 60 seconds JIS-L-
1094 (1980) 3-1- device was used. The test method is method A (half-life measurement method) and method B (electrostatic voltage). The results are summarized in Table 5.

[Table] From the above results, the antistatic light-shielding masking film of the present invention does not transmit light having a wavelength of 200 to 560 nanometers (nm) and has good light-shielding properties. Further, it is recognized that the surface of this masking film is not sticky, has appropriate peelability between the polyethylene terephthalate film support and the release layer, and has extremely excellent antistatic properties. Furthermore, the antistatic light-shielding masking film of the present invention is resistant to deterioration of the release layer due to photolithographic exposure, and is stable over a long period of time without floating at the cut end, and the cut end of the release layer with a cutter knife is sharp. In addition, it was observed that the dye did not stick to the plastic film support. (g) Effects of the Invention Since the antistatic light-shielding masking film of the present invention has the above structure, the peeling layer has good strength and the plastic film support has good light transmission. The release layer has excellent releasability.Even when the release layer is cut with a cutter knife, no lifting occurs in the non-released part.The cut of the release layer with the cutter knife is sharp.
In addition to having excellent properties such as excellent light-shielding properties and the ability to obtain precise photographic objects, it also has a non-sticky surface and does not allow dyes or pigments to stick to the plastic film support. Without,
Furthermore, it has an extremely excellent antistatic effect. In particular, in the present invention, since glycerin stearate is used as an antistatic agent, it does not significantly affect the adhesiveness of the release layer, and moreover, the adhesive strength of the release layer can be adjusted appropriately, and Since the removability can be maintained, it is easy to handle and extremely useful.

Claims (1)

[Claims] 1 A light-shielding masking film comprising a light-shielding plastic film support with a release layer mainly made of thermoplastic plastic, rubber, or a mixture thereof on one side, the release layer containing an antistatic agent that is solid at room temperature. 1. An antistatic light-shielding masking film, characterized in that the antistatic agent is glycerin stearate.