JPH08254811A - Light shielding masking film - Google Patents

Abstract

PURPOSE: To provide a light shielding masking film simultaneously solving problems on blocking resistance and moderate adhesiveness contrary to each other and problem on the aging stability of the physical properties of a coating film. CONSTITUTION: In this light shielding masking film with a light shielding peelable layer on the substrate, the binder component of the light shielding peelable layer consists essentially of 20-40wt.% rubberlike resin, 25-75wt.% vinyl chloride resin and 5-35wt.% OH group-contg. thermoplastic resin compatible with them.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light-shielding masking film mainly used in photolithography for cutting a required portion and peeling off an unnecessary portion to form a transparent image having a desired shape.

[0002]

2. Description of the Related Art Conventionally, as a light-shielding masking film used in the field of photoengraving and the like, it is known that a light-shielding release layer is provided directly or through an adhesive layer on a transparent support made of a plastic film. ing.

The former binder constituting the light-shielding release layer is, for example, one composed of nitrocellulose and a plasticizer (USP2576491), one composed of nitrocellulose, a nitrile rubber and an adhesion modifier (JP-A-61). No. 166549), nitrocellulose and an ethylene / vinyl acetate copolymer (JP-A 2-1).
88755).

Further, as the binder constituting the latter light-shielding release layer, for example, nitrile rubber and vinyl chloride /
Made of vinyl acetate copolymer (Japanese Patent Publication No. 58-460)
No. 11) etc.

Regarding the various properties generally required as a light-shielding masking film, such as peelability, coating film physical properties, blocking resistance, bleeding resistance and the like and their temporal stability, in the former constitution, an adhesive layer is used. Since the function can be shared with the light-shielding release layer, it is easy to select the resin composition forming the light-shielding release layer. On the other hand, in the latter configuration, since all of the required performances have to be included only in one layer, it is not possible to sufficiently satisfy all the required performances, which causes various problems such as blocking and adhesiveness. Was there.

Generally, in the light-shielding release layer of the light-shielding masking film, a binder component alone cannot cover all of the required characteristics, so that usually a plurality of components are required.
For example, it is constituted by a mixed balance of those that are adhered or adhered to the support and those that are not adhered.

Here, the substance to be adhered to the support or the substance to be adhered thereto usually gives plasticity to the coating film, and examples of low molecular weight substances include dibutyl phthalate, dioctyl phthalate, castor oil and the like. However, as a high molecular weight compound, a rubber-like elastomer such as nitrile rubber, acrylic rubber, urethane rubber or polyester is generally used.

As the substance which does not adhere to the support, vinyl chloride / vinyl acetate copolymer, vinyl chloride /
Vinyl chloride resins such as vinyl acetate / maleic acid copolymers and cellulose resins such as nitrocellulose are generally used.

The above-mentioned adhesive substance has a function of imparting plasticity, usually has a low glass transition point itself, and lowers the entire glass transition temperature if the system is compatible even when mixed.

On the other hand, many non-adhesive substances usually have hard physical properties, and most of them have a glass transition point higher than that of the former. In a conventional light-shielding masking film, components that are divided into these two groups are blended in a well-balanced manner to control properties such as adhesion to a support and blocking property.

However, if a large amount of an adhesive substance is added in order to sufficiently increase the adhesive strength to the extent that the light-shielding release layer does not drop off or curl up, the glass transition point of the entire light-shielding release layer lowers as described above. High temperature environment in summer, for example, the coating film softens during storage in a warehouse or shelf or during storage in a film dispenser, which causes a problem of blocking, and further, due to its plasticity in such a high temperature environment,
There may be a problem of film elongation during peeling.

On the other hand, if a large amount of a non-adhesive substance is added in order to raise the glass transition point of the light-shielding release layer as a whole, the blocking property is improved, but the adhesion property is poor, and the coating film may fall off or turn up. Problems occur, and the coating film becomes hard and brittle and becomes easy to cut.

In order to improve such blocking property, a method of adding an organic / inorganic filler to the light-shielding release layer may be considered, but the physical properties of the coating film are unstable over time, and the wear of the cutting blade is increased. Alternatively, due to the transparency of the coating film, only a few% of the binder component can be added, which is not sufficient for simultaneously improving the blocking property and other properties.

In addition to the above problems of blocking property and adhesive property, the conventional light-shielding masking film has another problem that the physical properties of the coating film change with time.

That is, in this type of light-shielding masking film, even if a conventional binder component is produced by mixing the plastic adhesive substance and the rigid non-adhesive substance in a combination that seems to be appropriate, the distribution route immediately after the production. The coating becomes considerably hard during a certain period until it is actually used.

Further, the binder component is a dye / pigment,
Since light-shielding substances such as alumina and zinc oxide, organic / inorganic fillers and other additives are contained, changes in physical properties with time are more likely to occur.

[0017]

SUMMARY OF THE INVENTION The present invention has the above-mentioned problems that cannot be solved conventionally, that is, both the blocking resistance and the appropriate adhesiveness are contradictory to each other, and the change in the physical properties of the coating film with time is stabilized. It is an object of the present invention to provide a light-shielding masking film that solves the problem at one time.

[0018]

The present invention provides a light-shielding masking film having a light-shielding release layer on a support, in which the binder component of the light-shielding release layer is at least a rubber-like resin, a vinyl chloride-based resin and those. Compatible OH
A thermoplastic resin containing a group, wherein the binder component is a rubber-like resin 20 to 40% by weight, a vinyl chloride resin 25 to
75% by weight, and an OH group-containing thermoplastic resin compatible with them is contained in an amount of 5 to 35% by weight.

It is preferable that the rubber-like resin is 25 to 35% by weight, the vinyl chloride resin is 35 to 65% by weight, and the OH group-containing thermoplastic resin compatible with them is 5 to 30% by weight. It is a feature.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The light-shielding masking film of the present invention will be specifically described below.

Examples of the transparent support include plastic films such as polyester, polycarbonate, triacetyl cellulose, polyvinyl chloride, acrylic, polystyrene, polyamide, polyimide, polyethylene and polypropylene, which are biaxially stretched in view of transparency. Polyester film is preferably used. Further, those having a thickness in the range of 25 to 250 μm are appropriately used.

The light-shielding release layer contains a specific binder component and a light-shielding substance for shielding actinic rays, and the specific binder contains a rubber-like resin in an amount of 20 to 40% by weight, preferably 25 to 35. % By weight, 25 to 75% by weight of vinyl chloride resin, preferably 35 to 65% by weight, and 5 to 35% by weight, preferably 5 to 30% by weight, of an OH group-containing thermoplastic resin compatible with them. It is a thing.

The rubber-like resin has adhesiveness to the transparent support and has a role of imparting flexibility to the coating film. Examples of such materials include nitrile rubber, acrylic rubber, urethane rubber, butadiene rubber, isoprene rubber, styrene-butadiene rubber, carboxyl group-containing nitrile rubber, butyl rubber, ethylene / vinyl acetate rubber,
One or more of ethylene / acrylic rubber, chlorinated polyethylene, chlorosulfonated polyethylene, and various thermoplastic elastomers can be used, and nitrile rubber is particularly preferable in terms of adhesiveness and compatibility.

As the vinyl chloride resin, one which is compatible with the above rubber-like resin and which is not sticky at room temperature is used. This vinyl chloride resin has a good coating property and forms a relatively hard coating film, and although the adhesiveness to the support is not sufficient,
Many of them are compatible with rubber-like resins and have the role of imparting flame retardancy and strength to the coating film, and adjusting the adhesiveness and flexibility. As such substances, one or more of vinyl chloride / vinyl acetate copolymer, vinyl chloride / acrylic copolymer, vinyl chloride / vinylidene chloride copolymer, chlorinated vinyl chloride resin and the like can be used.

By adjusting the blending ratio of the above two components, not only the adhesion of the coating film to the support and the flexibility of the coating film can be adjusted, but also the glass transition point of the coating film can be adjusted. As described above, it is not possible to obtain optimum performances of adhesiveness, flexibility, and glass transition point with only two components. In other words, the importance of adhesiveness and flexibility is such that the proportion of the rubber-like resin is slightly increased, which lowers the glass transition point of the coating film and causes a problem of blocking in a high temperature environment in summer.

Therefore, in the present invention, by adding an appropriate amount of OH group-containing thermoplastic resin in addition to these two components, blocking resistance, adhesiveness and flexibility can be simultaneously optimized. In this case, a part of the vinyl chloride resin from the two-component system of rubber-like resin and vinyl chloride resin is
When it is replaced with a thermoplastic resin containing an H group, even if the calculated total glass transition temperature of the three-component binder is lower than the total glass transition temperature of the two-component binder, the blocking property and the support The adhesiveness to is remarkably improved.

It is not clear why such a result is obtained, but it is thought that when the OH group-containing thermoplastic resin is mixed in a certain amount, the introduced OH group and the polar component of the other resin become a molecule. It is considered that the blocking property is improved by forming a pseudo bond by the inter-force, thereby suppressing the thermal mobility of the molecule and raising the apparent glass transition point or softening point. However, when the amount exceeds a certain amount, the amount of the resin other than the OH group-containing thermoplastic resin decreases, a pseudo bond is not formed, and the thermal motion of the molecule cannot be suppressed, so that the blocking property cannot be improved. Ah

Regarding the improvement of the adhesiveness by introducing the OH group, it can be considered that the OH group, which is an adhesive factor, improves the adhesiveness.

Regarding the stability of coating film properties over time, a general low-molecular weight plasticizer has a plasticizing effect on the entire coating film when mixed, but it is applied by evaporation over time or unevenness due to bleeding. The plasticizing effect of the film as a whole disappears.
However, when the mixed resins are compatible with each other and have a plasticizing effect, it is considered that the uniform state is maintained over time, and as a result, the stability of the physical properties is obtained.

Examples thereof include phenoxy resin, epoxy resin, acrylic resin, polyvinyl acetal, vinyl chloride / acrylic acid ester copolymer, vinyl chloride / vinyl acetate / vinyl alcohol copolymer, styrene / maleic acid half ester. One or two or more such as a cellulose resin can be used.

In the present invention, as the resin constituting the light-shielding release layer, 20 to 40% by weight, preferably 25 to 35% by weight of a rubber-like resin and 25% by weight of a vinyl chloride resin are used as the above three components.
-75 wt%, preferably 35-65 wt%, and OH group-containing thermoplastic resin 5-35 wt%, preferably 5-35 wt%
By using 30% by weight, problems such as blocking property can be solved.

Here, the rubber-like resin content of 20% by weight or more of the total resin makes it possible to impart adhesiveness to the support and flexibility of the coating film, and 40% by weight or less means adhesion. This is to prevent the film elongation at the time of peeling caused by the excessive flexibility and flexibility. A vinyl chloride resin content of 25% by weight or more based on the total resin can impart appropriate peelability, flexibility, and strength to the coating film, and a resin content of 75% by weight or less means that they are excessively lightly peeled or hard. This is to prevent overuse. The reason why the OH group-containing thermoplastic resin is 5% by weight or more of all the resins is to impart blocking property, adhesiveness, and stability of physical properties over time, and 35% by weight or less is too strong adhesion. This is because it is difficult to peel off a large area due to excessive strength, breakage of the coating film at peeling, and cohesive failure of the support.

When the glass transition point of the OH group-containing thermoplastic resin is lower than that of the vinyl chloride resin, the glass transition point of the entire coating film should be lowered, but the addition of this improves markedly the blocking property. It

In the present invention, by utilizing this phenomenon, it is possible to sacrifice the blocking property by using the optimum compounding ratio of adhesiveness and flexibility, which could not obtain each optimum performance at a time in the two-component system. It became possible to obtain the stability of physical properties over time without doing so.

In addition to the resins described above, additives such as light-shielding dyes / pigments, organic / inorganic matting agents, leveling agents, antistatic agents, and humidity control agents may be added to the light-shielding release layer. You can

The light-shielding release layer has a thickness of 10 to 50 μm.
The range is m, preferably 15 to 45 μm.

Further, in the method for producing a light-shielding masking film of the present invention, a coating solution prepared by dissolving or dispersing the above resin and necessary additives in a ketone-based or aromatic solvent is kissed on a transparent support or a bar. , Reverse, knife, gravure, microgravure, and other coating methods.

[0038]

The light-shielding masking film of the present invention having the above-mentioned constitution is improved in blocking resistance, adhesion to a support and stability of physical properties of a coating film over time.

[0039]

Embodiments of the present invention will be described below.

On a polyester film having a thickness of 100 μm, a coating solution for a light-blocking release layer having the composition shown in Table 1 was applied with a Meyer bar, dried at 120 ° C. for 6 minutes, and a light-shielding masking film having a thickness of 23 μm was coated. I got a film.

[0041]

[Table 1]

Next, the light-shielding masking films of Examples 1 to 4 and Comparative Examples 1 to 5 were stored for 1 week in an atmosphere of 20 ° C. and 65% RH, and the following physical properties were evaluated. Table 2 shows the results.

[0043]

[Table 2]

Here, regarding the blocking property, immediately after the coating film was dried, sampling was carried out, and an accelerated test was conducted for 24 hours at a pressure of 50 g / cm ^{2 in} an atmosphere of 50 ° C. and 10% RH. It was judged according to the standard.

[0045]

[Table 3]

Generally, from the correlation between the blocking occurrence state in the warehouse of rolls in the product form or the semi-finished product form and the acceleration test, if the blocking area in acceleration is 5% or less, preferably 2% or less, It has been confirmed that there is practically no problem.

The yield value, the breaking value and the coating film elongation were measured by sampling the coating film at 100 mm × 15 mm, and the peel strength was measured at 200 mm × 25 mm.
It sampled to mm and performed.

In Examples 1 to 4, even after 1 year in an atmosphere of 20 ° C. and 65% RH, there was little change in physical properties over time,
Stable yield value (hardness of coating film), coating film elongation, and peel strength were maintained, and good blocking property was exhibited. On the other hand, in Comparative Examples 1 to 5, none of the coating films simultaneously satisfies hardness, elongation, peeling property and blocking property.

[0049]

INDUSTRIAL APPLICABILITY As described above, the light-shielding masking film of the present invention maintains blocking resistance and appropriate adhesiveness over time, and blocks during transportation or storage of the masking film. It can be stored without worrying about the storage condition, and no need for slip sheets.

Further, the physical properties of the masking film are stable with time, and the cutting performance and the peeling performance are always the same regardless of the stage of storage immediately after production and during storage.

Claims (2)

[Claims] 1. In a light-shielding masking film having a light-shielding release layer on a transparent support, the film-forming material constituting the light-shielding release layer comprises a rubber resin 20 to 40% by weight and a vinyl chloride resin 25 to 75. Wt%, O compatible with them
A light-shielding masking film, which comprises 5 to 35% by weight of an H group-containing thermoplastic resin. 2. A light-shielding masking film having a light-shielding release layer on a transparent support, wherein the film-forming material forming the light-shielding release layer comprises 25 to 35% by weight of a rubber-like resin and a vinyl chloride resin 35 to 65. Wt%, O compatible with them
A light-shielding masking film containing 5 to 30% by weight of an H group-containing thermoplastic resin.