JPH0683066A - Photoresist cover film for photosensitive printing plate - Google Patents

Abstract

PURPOSE:To obtain a flexible film having rough surface, excellent in flatness, less in projections of foreign matter such as gel or fish-eye, and excellent in peeling property from a photoresist and protection property for a photoresist. CONSTITUTION:This photoresist cover film for a photosensitive printing plate is a laminated film consisting of a biaxially oriented polyolefin film (layer A) and a rough layer (layer B) laminated on at least one surface of the layer A. The rough layer (layer B) has >=10 piece/mm roughness density PC1 of >1mum roughness, and the laminated film has 0.0002-0.010 double refraction, >=10% total haze, and <=5 piece/100mm<2> gel and fish-eye.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoresist cover film for photosensitive plate making. More specifically, it ’s flexible,
The present invention relates to a photoresist cover film for a photosensitive plate having a rough surface, excellent flatness, and appropriate adhesiveness and releasability from a photoresist.

[0002]

2. Description of the Related Art Conventionally, polyethylene or polypropylene film has been used as a photoresist cover film for photosensitive plate making (JP-A-1-179154).

It is preferable that the cover film has small thickness unevenness, good flatness, and few foreign matter projections (gel or fish eyes). Moreover, it must be flexible and have good releasability from the photoresist. Furthermore, since dry film photoresist (hereinafter abbreviated as DFR) is applied to the polyester film of the base material and the cover film is attached and rolled in a long roll, the photoresist in the core is in an oxygen-deficient state. Since there is a problem of self-crosslinking and there is a recent demand for lengthening the DFR, there is a demand for the cover film to have a rough surface and a thin film.

Further, there is known a film in which a polymethylpentene and a copolymer resin with other olefins are laminated on the surface layer of polypropylene for the purpose of improving the releasability (Japanese Patent Publication No. 57-44465, Japanese Patent Publication No. 03). -71975
Etc.).

[0005]

However, the above-mentioned conventional polyethylene film has the drawbacks of large thickness unevenness and poor flatness, and many gel-like foreign matter projections. Further, it is necessary as a DFR cover film. What
It is very difficult to make a rough and thin film. On the other hand, polypropylene film is easy to make a thin film with a rough surface, but it is too stiff and has poor releasability from the photoresist, and it is easy to get ripples on the photoresist when stripping. have.

Further, a film obtained by laminating a polymethylpentene and a copolymer resin with other olefins on the surface layer of polypropylene for the purpose of improving the releasability is too strong and has a poor releasability from the photoresist. When the photoresist is peeled from the photoresist, ripples are formed on the photoresist, and a film in which a polymethylpentene and a copolymer resin with another olefin are laminated on the surface layer of the polypropylene is a polypropylene-polymethylpentene film. Due to poor compatibility, there is a problem that fish eyes frequently occur in the recovery process.

An object of the present invention is to provide a photoresist cover film for a photolithography plate which is rough and has a small thickness unevenness, good flatness, few foreign matter protrusions (gel or fish eyes) and good releasability from the photoresist. To provide.

[0008]

A photoresist cover film for photosensitization according to the present invention, which is intended for this purpose, comprises a biaxially stretched polyolefin film (A layer) on at least one surface thereof,
A laminated film formed by laminating rough surface layers (layer B),
The rough surface layer (B layer) has a roughness density PC1 of 1 μm or more of 10
1 / mm or more, the laminated film has a birefringence of 0.002 to 0.010 and a total haze of 1
0% or more, 5 gels / fish eyes / 100
mm ² or less.

In the biaxially stretched polyolefin film (A layer) of the present invention, an ethylene-propylene copolymer,
Ethylene-propylene-butene copolymer, propylene-
It is at least one resin selected from butene copolymers. Polyolefin resins such as polyethylene, polypropylene and polybutene may be further mixed with these copolymers to the extent that the film properties are not deteriorated. Among these, a mixture of an ethylene-propylene-butene copolymer and polyethylene is more preferable. The ethylene content of the ethylene-propylene-butene copolymer is 0.
It is preferable that the content of 5 to 10% by weight and the content of butene be 0.2 to 20% by weight because no gel-like substance is generated, and that the birefringence is within a specific range. Polyethylene is a medium density,
A low density or a linear low density mixture of 2 to 50% by weight is preferable because of its flexibility. The biaxially stretched polyolefin film contains a crystal nucleating agent, an antioxidant,
Heat stabilizers, slip agents, antistatic agents, UV absorbers, etc.
You may contain in the range which does not worsen peelability and optical characteristics.

The biaxially stretched polyolefin film (A
The birefringence of the layer is preferably in the range of 0.002 to 0.010. If the birefringence is 0.002 or less, the flatness is poor, and if it exceeds 0.010, the waist becomes too strong,
It is not preferable because peelability from the photoresist is poor and ripples are likely to be formed on the photoresist when peeling from the photoresist.

The average surface roughness Ra of the biaxially stretched polyolefin film (A layer) is preferably 0.05 μm or more. When the average surface roughness Ra is less than 0.05, when used as a cover film for DFR, the polyester film of the base material and the cover film adhere to each other,
Since there is no air layer between the polyester film and the cover film, it is impossible to prevent the photoresist in the core from being oxygen-deficient and self-crosslinking.

The photoresist cover film for photosensitive plate making of the present invention comprises the biaxially stretched polyolefin film (A
It is a laminated film formed by laminating a rough surface layer (B layer) on at least one surface of the (layer). Preferably, a three-layer laminated film in which the rough surface layer (B layer) is laminated on both surfaces, a photoresist is applied to the polyester film of the base material, a cover film is attached, and a long roll is rolled.
In R, the photoresist in the winding core is in an oxygen-deficient state and self-crosslinks due to an air layer that has entered into a minute space formed between the photoresist and the cover film and the polyester film of the base material and the cover film. Can be prevented.

The rough surface layer (B layer) must have a roughness density PC1 of 1 μm or more, preferably 2 to 5 μm, of 10 pieces / mm or more. When the roughness density PC1 of 1 μm or more is 10 pieces / mm or more, when peeled from the photoresist, there is no uneven peeling and smooth peeling can be performed, and the photoresist is not damaged. Roughness density P of 1 μm or more
When C1 is less than 10 pieces / mm, the adhesive force with the photoresist becomes strong and the releasability deteriorates, and the photoresist has ripple-like scratches, which is not preferable.

When used as a cover film for DFR, the roughness density PC1 of 1 μm or more is 10 pieces / m.
When it is less than m, the photoresist in the core portion is in an oxygen-deficient state, which is not preferable.

The resin composition of the rough surface layer (B layer) of the present invention is
It is a mixture of low density polyethylene or linear low density polyethylene and an ethylene-propylene block copolymer resin. The mixing amount is 50 to 90% by weight of low-density polyethylene or linear low-density polyethylene, and the ethylene-propylene block copolymer is 10 to 50% by weight, and the surface layer has a roughness density PC1 of 1 μm of 10 pieces. / Mm or more, which is preferable. Roughness density PC1 of 1μm is 1
In order to obtain 0 or more / mm, when the mixture is melt-mixed and extruded, the spherulites are gradually cooled and solidified while growing.
It is obtained by stretching at a stretching temperature which is equal to or higher than the melting point of low density polyethylene or linear low density polyethylene.

The wetting tension of the rough surface layer (B layer) is 35 dy.
It is preferably ne / cm or less. Wetting tension is 35
If it exceeds dyne / cm, the adhesive force with the photoresist becomes strong and the peeling property deteriorates, causing ripples on the photoresist, which is not preferable.

The birefringence of the photoresist cover film for photosensitive plate making of the present invention must be in the range of 0.002 to 0.010. If the birefringence is 0.002 or less, the flatness is poor, and if it exceeds 0.010, the rigidity is too strong, and the releasability from the photoresist is poor, and when the photoresist is stripped, ripples are wavy. It is not preferable because it tends to stick.

In the photoresist cover film for photosensitive plate making of the present invention, the total haze of one film is 10% or more, preferably 20% to 60%. If the total haze is less than 10%, the photoresist in the surface layer portion of the DFR is photosensitively deteriorated by ultraviolet rays, which is not preferable.

The photoresist cover film for photosensitive plate making of the present invention comprises 5 gels / fish eyes / 1
It is necessary that the size is 00 mm ² or less. When the number of gels and fish eyes is 5 pieces / 100 mm ² or more, a large amount of air can be trapped when bonding with the photoresist,
This is a defect in appearance when used as a DFR.

The photoresist cover film for photosensitive plate making of the present invention has a sum of Young's moduli in the longitudinal direction and the width direction of 150.
It is preferably not more than kg / mm ² . 150 kg /
If it exceeds mm ² , the stiffness becomes too strong, the peeling property from the photoresist deteriorates, and the photoresist is rippled, which is not preferable. The lower limit of the Young's modulus is not particularly limited, but it is necessary to have sufficient rigidity to be processed as a cover film, and a range of 50 to 100 kg / mm ² is preferable.

In the case of a two-layer laminated film of the A layer and the rough surface layer (B layer), the rough surface layer (B layer) is attached so that it is on the photoresist side, whereby the photoresist and the cover film are formed. It is possible to prevent the photoresist in the winding core from becoming oxygen deficient and self-crosslinking due to the air layer that has entered the minute space formed between the two. In addition, there is no appearance defect due to entrapment of large air when it is applied to the photoresist.

Further, one layer of the A layer is used as the B layer, and the other layer of the A layer is laminated with a polyolefin layer (C layer) to which organic spherical particles are added to form a C layer / A layer / B layer. It may be a three-layer laminated film.

The polyolefin layer (C layer) is at least one resin selected from an ethylene-propylene copolymer, an ethylene-propylene-butene copolymer and a propylene-butene copolymer.

Organic spherical particles added to the polyolefin layer (C layer) include crosslinked silicon, crosslinked polystyrene,
For example, cross-linked polymethylmethacrylate. The particle size of the organic spherical particles is preferably in the range of 1 μm to 6 μm.
The addition amount is preferably in the range of 0.1 to 2% so as not to deteriorate the total haze of the film.

The thickness of the photoresist cover film for photosensitive plate making of the present invention is not particularly limited, but it is 5
.About.50 .mu.m is preferable, and 10 to 20 .mu.m is more preferable for the demand for lengthening the DFR. The lamination thickness of the rough surface layer (B layer) and the particle-added layer (C layer) is not particularly limited, but is preferably 0.2 to 5 μm, and in consideration of releasability, optical characteristics, gel and fish. 0.5-3μ
m is more preferred.

One or both surfaces of the photoresist plate film for photosensitive plate making of the present invention may be subjected to a corona discharge treatment in air or in an atmosphere of nitrogen or carbon dioxide gas, as long as the releasability is not deteriorated. This corona discharge treatment is carried out when the adhesiveness with the photoresist is too small, or when the DFR is used, the winding shape is deteriorated and other handling problems occur. By this corona discharge treatment, the degree of peelability can be adjusted to an appropriate state.

Next, a method of manufacturing the photoresist cover film for photosensitive plate making of the present invention will be described, but the method is not necessarily limited thereto.

As the raw material composition of the layer A, a mixture of 75% by weight of an ethylene-propylene-butene copolymer having an ethylene content of 3% by weight and a butene content of 5% by weight and a linear low density polyethylene of 25% by weight. The resin is fed to the first extruder. On the other hand, as the raw material composition of the rough surface layer (B layer), the linear low density polyethylene is 75% by weight and the ethylene content is 20.
25 wt% ethylene-propylene block copolymer 25 wt% mixed resin is fed to the second extruder. Molten resins from both extruders are laminated in one die and coextruded. Then, the laminated film is obtained by cooling and solidifying on a cooling drum. The obtained laminated film was treated with 100 to 140
It is stretched 3 to 7 times in the longitudinal direction at a stretching temperature of ℃, and then 5 to 15 in the width direction at a stretching temperature of 120 to 150 ℃ in the width direction.
Stretching twice, then giving a few percent relaxation in the width direction,
It is heat-set at a temperature of 0 to 150 ° C., the edges are cut off, and then wound.

The layer B is not limited to the above-mentioned coextrusion, and may be before uniaxial stretching or before biaxial stretching. The biaxial stretching method may be any known method, for example, simultaneous biaxial stretching, sequential biaxial stretching, tuber stretching, etc., but sequential biaxial stretching is preferable in terms of planarity.

The lamination of the C layer containing spherical particles is
The three layers are used to laminate C layer / A layer / B layer and coextrude, or they are laminated in the same manner as the above B layer.

If necessary, the surface of the film of the present invention obtained as described above is subjected to corona discharge treatment or plasma treatment in an atmosphere of air, nitrogen gas, carbon dioxide gas or the like.

When the film of the present invention is used as a photoresist cover film for DFR photosensitive plate making, first, while pulling out the base material wound into a roll,
A photoresist is applied to the surface by using a coating device. Then, the film of the present invention is roll-pressed so as to cover the coated and dried photoresist, and the film is long-rolled. After that, when a photosensitive plate is used, the photoresist is adhered to the substrate while the cover film is peeled from the photoresist. At this time, the photoresist cover film for photolithography of the present invention has a good releasability from the photoresist and does not have ripple-like scratches on the photoresist surface. Further, the DFR wound in a long roll has good air circulation properties, and there is no difference in quality between the photoresist on the surface layer portion and the photoresist on the winding core portion.

[0033]

[Characteristic measuring method and effect evaluating method] The characteristic value measuring method and effect evaluating method of the present invention are as follows.

(1) Birefringence index Methyl salicylate was used as a mount solution in an Abbe refractometer, and the refractive index nx in the longitudinal direction and the refractive index ny in the width direction of the film were measured and determined by the difference between nx and ny. .

(2) Roughness density PC1 and surface roughness Ra As described in JIS B 0601-1976, the roughness was measured using a stylus type surface roughness meter. The cutoff was 0.25 mm and the measurement length was 5 mm.

(3) Total haze Measured according to JIS K 6714.

(4) Gel and fish eye film The number is shown per 100 mm ² . ◯: less than 5 Δ: 5 or more and less than 10 x: 10 or more

(5) Peelability A sample is laminated on a photoresist under a yellow lamp at 25 ° C. and cut into a width of 25 mm. Then, 90 ° peeling is performed in Tensilon, and judgment is made based on the adhesive force, peeling noise, and the photoresist surface state after peeling the sample. ◯: Peeling was smooth, there was no peeling noise, and there were no ripple-like scratches on the photoresist surface state after peeling the sample. X: The adhesive strength is strong, there is peeling noise, and ripples are scratched on the photoresist surface state after peeling the sample.

(6) Young's modulus The sample was cut into strips with a width of 10 mm, and the measurement length was 50 m.
m. Tensileron allows pulling speed of 20 mm / m
The rising curve is recorded on a chart paper at a chart speed of 500 mm / min. After drawing a tangent line to the rising curve from the base point, draw a perpendicular line at a point 25 mm from the base point and read the intersection of the tangent line and the perpendicular line as strong. And
Young's modulus (kg / mm ² ) is calculated by the following formula. Young's modulus (kg / mm ² ) = [Strength (kg) × Test length (m
m) × chart speed (mm / min)] ÷ [pulling speed (mm / min) × 25 mm × film thickness (mm) ×
Film width (mm)]

(7) Flatness Thickness unevenness is measured using a dial gauge. ◯: less than ± 10% of average thickness x: ± 10% or more of average thickness

(8) Wetting tension According to ASTM D 2578 67T, 20 ° C., 65
% It was measured in an atmosphere.

(9) Appearance of DFR A photoresist was applied to a polyester film as a base material, and a cover film was attached thereto to form a DFR, which was evaluated by observing the appearance when wound in a roll shape for 500 m.

◯: The appearance is good without the entrapment of large air. X: Large air bites are scattered and appearance defects are observed.

(10) Self-crosslinking state of DFR photoresist After 500 m of DFR was wound and left under a yellow lamp at 25 ° C. for 6 months, the self-crosslinking state of the DFR surface layer and core was observed. ◯: There was no self-crosslinking in the photoresist of the surface layer portion of the DFR and the core portion. X: The photoresist in the surface layer portion or the core portion of the DFR was partially crosslinked.

[0045]

EXAMPLES The present invention will be described based on Examples and Comparative Examples.

Example 1 As the raw material composition of the layer A, a linear low-molecular composition was obtained, which was 75% by weight of an ethylene-propylene-butene copolymer having an ethylene content of 2.5% by weight and a butene content of 4.5% by weight. A mixed resin having a density of 25% by weight of polyethylene was fed to the first extruder.
On the other hand, as the raw material composition of the rough surface layer (B layer), linear low-density polyethylene 75% by weight and ethylene-propylene block copolymer 25% by weight with an ethylene content of 20% by weight.
Was fed to the second extruder. Molten resin from both extruders was laminated into three layers of B layer / A layer / B layer in one die and coextruded. Then, it was cooled and solidified on a cooling drum at 40 ° C. to obtain a laminated film. The obtained laminated film is preheated at 100 ° C. and stretched 5 times in the longitudinal direction at a stretching temperature of 120 ° C., then stretched 10 times in the width direction at a stretching temperature of 135 ° C., and then 5 times in the width direction. It was heat-set at a temperature of 145 ° C. while giving a relaxation of%, and the edges were cut off and then wound. The thickness composition of the obtained film is 1 μm /
It was 13 μm / 1 μm.

The film of the present invention thus obtained was used as D
In order to evaluate as a photoresist cover film for FR photosensitization, a photoresist layer (composed of a monomer, an oligomer or a polymer having an epoxy group and a diazonium salt) coated on a polyester film as a base material and dried was used. It was roll-bonded at room temperature under a yellow lamp of 20 ° C. and wound into a roll.

Table 1 shows the results of evaluation of the film quality characteristics and the photoresist cover film for photosensitive plate making. As is clear from the table, the film of the present invention has a rough surface with a small thickness unevenness and good flatness,
There were few foreign matter protrusions such as gels and fish eyes, and the peelability from the photoresist was excellent. Also, D
The FR had good air flowability and did not undergo self-crosslinking due to oxygen deficiency of the photoresist in the winding core.

Example 2 As the raw material composition of the A layer, a mixed resin of 75% by weight of an ethylene-propylene random copolymer having an ethylene content of 4.5% by weight and 25% by weight of low-density polyethylene was used as a first composition.
It was fed to the extruder. On the other hand, as a raw material for the rough surface layer (layer B), a mixed resin containing 75% by weight of low-density polyethylene and 25% by weight of an ethylene-propylene block copolymer having an ethylene content of 20% by weight was supplied to the second extruder. . Molten resin from both extruders was laminated into two layers of B layer / A layer / B layer in one die and coextruded. Next, it was cooled and solidified on a cooling drum at 40 ° C. to obtain a laminated film. The obtained laminated film is preheated at 100 ° C. and stretched 5 times in the longitudinal direction at a stretching temperature of 120 ° C., then stretched 10 times in the width direction at a stretching temperature of 135 ° C., and then 5 times in the width direction. It was heat-set at a temperature of 145 ° C. while giving a relaxation of%, and the edges were cut off and then wound. The resulting film has a thickness composition of 1
It was μm / 14 μm.

Film quality characteristics and photolithography process were carried out in exactly the same manner as in Example 1 except that the rough surface layer (B layer) of the film of the present invention thus obtained was roll-pressed so as to face the photoresist. The results of evaluation as a photoresist cover film are shown in Table 1. As is apparent from the table, the film of the present invention had a rough surface, small thickness unevenness, good flatness, few foreign matter protrusions such as gel and fish eyes, and excellent peelability from the photoresist. Further, the DFR had good air flowability and did not undergo self-crosslinking due to oxygen deficiency of the photoresist in the winding core.

Example 3 As the raw material composition of the layer A, a mixed resin of 60% by weight of a propylene-butene copolymer having a butene content of 19% by weight and 40% by weight of a linear low-density polyethylene was used as a first extruder. Supplied to. On the other hand, as raw materials for the rough surface layer (B layer), 80% by weight of linear low-density polyethylene and an ethylene content of 15
20% by weight of the ethylene-propylene block copolymer mixed resin was fed to the second extruder. Film quality characteristics and photosensitization plate were manufactured in exactly the same manner as in Example 1 except that the molten resin from both extruders was co-extruded in three layers of B layer / A layer / B layer in one die. The results of evaluation as a photoresist cover film are shown in Table 1. As is apparent from the table, the film of the present invention had a rough surface, small thickness unevenness, good flatness, few foreign matter protrusions such as gel and fish eyes, and excellent peelability from the photoresist. Further, the DFR had good air flowability and did not undergo self-crosslinking due to oxygen deficiency of the photoresist in the winding core.

Example 4 As the raw material composition of the C layer, ethylene containing 2.5% by weight of cross-linked polystyrene spherical particles having a particle diameter of 2 μm and having an ethylene content of 2.5% by weight and a butene content of 4.5% by weight was used. The propylene-butene copolymer resin was supplied to a third extruder, and the uniaxially stretched film stretched in the longitudinal direction of Example 2 was passed between cooled nip rolls, and the C layer was placed between the A layer surface and the roll of the stretched film. The layer raw material was melt-extruded and pressure-bonded, and subsequently stretched in the width direction and wound in the same manner as in Example 2.
The thickness composition of the obtained film is C layer / A layer / B layer is 1
It was μm / 13 μm / 1 μm.

The thus obtained film of the present invention was evaluated in the same manner as in Example 1 as a film quality characteristic and a photoresist cover film for photolithography. The results are shown in Table 1. As is apparent from the table, the film of the present invention had a rough surface, small thickness unevenness, good flatness, few foreign matter protrusions such as gel and fish eyes, and excellent peelability from the photoresist. Further, the DFR had good air flowability and did not undergo self-crosslinking due to oxygen deficiency of the photoresist in the winding core.

Comparative Example 1 As a raw material composition of the layer A, a homopolymer of a propylene-butene copolymer having a butene content of 19% by weight was supplied to a first extruder and extruded. Then, it was cooled and solidified on a cooling drum at 40 ° C. to obtain a single film. The obtained single film was preheated at 90 ° C. and stretched 6 times in the longitudinal direction at a stretching temperature of 110 ° C., then stretched 10 times in the width direction at a stretching temperature of 120 ° C., and then 5 times in the width direction. It was heat-set at a temperature of 135 ° C. while giving a relaxation of%, and the edges were cut off and then wound. The thickness composition of the obtained film was 15 μm.

The thus obtained film was evaluated in the same manner as in Example 1 as a film quality characteristic and a photoresist cover film for photosensitive plate making, and the results are shown in Table 1. As is apparent from the table, the film outside the scope of the present invention has a defect in appearance because it can be entrapped with a large amount of air when it is pressure-bonded to the photoresist, and has poor peelability from the photoresist. there were. Further, the air flowability of the DFR was poor and self-crosslinking occurred due to oxygen deficiency of the photoresist in the core.

Comparative Example 2 As the raw material composition of the layer A, a linear low content of 75% by weight of ethylene-propylene-butene copolymer having an ethylene content of 2.5% by weight and a butene content of 4.5% by weight. A mixed resin having a density of 25% by weight of polyethylene was fed to the first extruder.
On the other hand, as a raw material composition of the layer B, evaluation was carried out as a photoresist cover film for photosensitization in exactly the same manner as in Example 1 except that a linear low-density polyethylene single resin was supplied to the second extruder. The results are shown in Table 1. As is apparent from the table, the film outside the scope of the present invention has a defect in appearance because it can be entrapped with a large amount of air when it is pressure-bonded to the photoresist, and has poor peelability from the photoresist. there were. Further, the air flowability of the DFR was poor and self-crosslinking occurred due to oxygen deficiency of the photoresist in the core.

Comparative Example 3 As the raw material composition of the layer A, polypropylene resin was supplied to the first extruder. On the other hand, as a raw material composition of the layer B, an ethylene-propylene block copolymer resin having an ethylene content of 19% by weight was supplied to the second extruder. Molten resin from both extruders was laminated into three layers of B layer / A layer / B layer in one die and coextruded. Then, it was cooled and solidified on a cooling drum at 40 ° C. to obtain a laminated film. The obtained laminated film is preheated at 125 ° C. and stretched 5 times in the longitudinal direction at a stretching temperature of 130 ° C., and subsequently stretched 10 times in the width direction at a stretching temperature of 165 ° C., and then 5 times in the width direction. It was heat-set at a temperature of 165 ° C. while giving a relaxation of%, and the edges were cut off and then wound. The thickness composition of the obtained film is 1 μm /
It was 13 μm / 1 μm.

In the same manner as in Example 1, the quality characteristics of the film and the evaluation as a photoresist cover film for photosensitive plate making were evaluated, and the results are shown in Table 1. As is apparent from the table, the film outside the scope of the present invention was inferior in releasability from the photoresist.

Comparative Examples 4 and 5 As the biaxially stretched polyolefin film, low density polyethylene was used in Comparative Example 4 and linear low density polyethylene was used in Comparative Example 5 to form a film by the tubular method. The thickness of each of the obtained films was 25 to 30 μm, the thickness variation was large, the flatness was poor, and the gel was rich.

The obtained film was evaluated in the same manner as in Example 1 as a film quality characteristic and a photoresist cover film for photosensitive plate making, and the results are shown in Table 1. As is apparent from the table, the film outside the scope of the present invention has a large air entrapment when it is pressure-bonded to the photoresist, has a bad winding appearance and has a defect in appearance, and is peeled from the photoresist. It was inferior in sex. Further, the air flowability of the DFR was poor and self-crosslinking was caused by oxygen deficiency of the photoresist in the core.

[0061]

[Table 1]

[0062]

As described above, the photoresist cover film for photosensitive plate making of the present invention has a specific rough surface on at least one side of a biaxially oriented polyolefin film (A layer) having a birefringence index within a specific range. In a laminated film formed by laminating layers (layer B), it is a film in which the total haze of the laminated film and gel and fish eyes are optimized, and produces the following excellent effects.

(1) Small thickness unevenness and good flatness,
There are few protruding foreign matters such as gel and fish eyes, and D
Good appearance when set to FR.

(2) Flexible and excellent in releasability from the photoresist.

(3) Since the surface to be bonded to the photoresist is a specific rough surface layer, there is no large air entrapment during roll pressure bonding, the process stability is excellent, and the appearance when using DFR is good.

(4) Further, by using a specific rough surface layer, the air flowability in the case of DFR is good, and the photoresist in the core does not self-crosslink due to oxygen deficiency.

(5) Since the film haze is high, D
Prevents the surface layer portion of FR from being crosslinked by ultraviolet rays.

Claims (3)

[Claims] 1. A biaxially stretched polyolefin film (A
Layer) on at least one side of which a rough surface layer (B layer) is laminated, and the rough surface layer (B layer) has a roughness density PC1 of 1 μm or more of 10 pieces / mm or more, The laminated film has a birefringence of 0.002 to 0.010, a total haze of 10% or more, and gel and fish eyes of 5 pieces / 100 mm ² or less. Cover film. 2. The biaxially oriented polyolefin film (layer A) is at least one resin selected from ethylene-propylene copolymer, ethylene-propylene-butene copolymer and propylene-butene copolymer resin. The photoresist cover film for photosensitive plate-making according to claim 1, which comprises: 3. The rough surface layer (B layer) comprises a mixture of low density polyethylene or linear low density polyethylene and an ethylene-propylene block copolymer resin. A photoresist cover film for the photolithography as described above.