Photosensitive dry film protective film and preparation method thereof

Abstract

The invention belongs to the technical field of protective films, and discloses a photosensitive dry film protective film and a preparation method thereof. The photosensitive dry film protection film comprises an anti-sticking layer, a middle layer and a release layer, the anti-sticking layer is made of first low-density polyethylene, and the haze of the first low-density polyethylene is 10%-30%; the release layer comprises first linear low-density polyethylene and a release agent; the middle layer comprises second low-density polyethylene, second linear low-density polyethylene, nano silicon dioxide and an antioxidant, the antioxidant is obtained by compounding a hindered phenol antioxidant and a phosphite antioxidant, and the content of the antioxidant is smaller than or equal to 200 ppm. Common polyethylene is used as a main raw material, and nano silicon dioxide is used as a nucleating agent to realize crystal point control; the content of the antioxidant is strictly controlled, the influence of the antioxidant on the photosensitive dry film is reduced, and long-acting oxidation resistance is achieved through a specific hindered phenol antioxidant and phosphite ester antioxidant compound system under the low-content condition.

Description

Technical Field

[0001] The present invention belongs to the technical field of protective films, and in particular relates to a photosensitive dry film protective film and a preparation method thereof. Background Art

[0002] With the rapid development of the electronic information industry, photosensitive dry film, a core material in printed circuit board (PCB) manufacturing, has placed higher demands on its performance. Traditionally produced photosensitive dry film protective films often suffer from the distribution of large crystal particles. The presence of large crystal particles affects the transmittance and uniformity of the protective film, thereby affecting the optical performance of the photosensitive dry film and the subsequent photolithography accuracy. Furthermore, to extend the life of photosensitive dry film protective films, traditional protective films require the addition of high concentrations of antioxidants. However, these antioxidants easily migrate into the photosensitive adhesive layer of the photosensitive dry film, affecting the stability and reliability of the photosensitive dry film. Summary of the Invention

[0003] The present invention aims to improve at least one technical problem in the background technology.

[0004] A first aspect of the present invention provides a photosensitive dry film protective film, comprising an anti-adhesive layer, an intermediate layer and a release layer, wherein the anti-adhesive layer is a first low-density polyethylene, and the haze of the first low-density polyethylene is 10%-30%; The release layer includes a first linear low-density polyethylene and a release agent; The middle layer comprises polyethylene, nano silicon dioxide and antioxidant. The polyethylene comprises second low-density polyethylene and second linear low-density polyethylene. The antioxidant is compounded by hindered phenol antioxidant and phosphite antioxidant. The content of the antioxidant is ≤200ppm.

[0005] The present invention designs the photosensitive dry film protective film into three layers: an anti-sticking layer, an intermediate layer and a release layer, and the three layers each have different functions.

[0006] Among them, the anti-sticking layer is the outermost layer. By using low-density polyethylene with a certain haze, it can prevent the mother roll from sticking during the winding process, thereby protecting the winding quality of the finished photosensitive dry film. The anti-sticking layer of the present invention does not require additional anti-sticking agents (such as diatomaceous earth and talcum powder, etc.), thereby improving the cleanliness of the product and improving the uniformity of the photosensitive dry film during exposure.

[0007] The middle layer serves as the main supporting layer, and can provide basic strength and flexibility through the combination of low-density polyethylene and linear low-density polyethylene; at the same time, nano-silica is used as a nucleating agent. After the nano-silica is evenly dispersed, it promotes the refinement of polyethylene crystals, which can reduce the generation of large-sized crystal points, prevent large-sized crystal points from becoming stress concentration points, resulting in a decrease in the tensile strength of the product, and prevent large-sized crystal points from causing a decrease in the light transmittance of the product and affecting the uniformity of the photosensitive dry film during exposure; in addition, hindered phenols and phosphites are used as compound antioxidants to delay material aging. The specific hindered phenol antioxidant and phosphite antioxidant compound system in the present invention can greatly improve the antioxidant effect, so that the antioxidant system can ensure the antioxidant effect even when it is controlled under trace conditions of ≤200ppm. The content control of the antioxidant can reduce the pollution problem caused by its migration to the photosensitive dry film, thereby ensuring the stability and reliability of the photosensitive dry film.

[0008] The silicone powder in the release layer is evenly dispersed in the linear low-density polyethylene to form a microphase separation structure, which can ensure the adhesion of the protective film and the photosensitive dry film and facilitate subsequent peeling.

[0009] Furthermore, the mass ratio of the second low-density polyethylene to the second linear low-density polyethylene is (30-50):(60-80).

[0010] Furthermore, the mass ratio of polyethylene to nano-silicon dioxide is 100:(0.5-1), and the average particle size of the nano-silicon dioxide is 5nm-50nm.

[0011] Furthermore, the mass ratio of the hindered phenol antioxidant to the phosphite antioxidant is 1:1, the hindered phenol antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and the phosphite antioxidant is tris(2,4-di-tert-butylphenyl)phosphite.

[0012] Furthermore, the mass ratio of the first linear low-density polyethylene to the release agent is 100:(1-3), and the release agent is silicone powder.

[0013] Furthermore, the total thickness of the photosensitive dry film protective film is 5 μm-50 μm, and the thickness ratio of the anti-sticking layer, the intermediate layer and the release layer is (15-25):(50-70):(15-25).

[0014] A second aspect of the present invention provides a method for preparing the above-mentioned photosensitive dry film protective film, comprising the following steps: preparing raw materials for the anti-sticking layer to obtain an anti-sticking layer material; respectively mixing the raw materials of the intermediate layer and the release layer to obtain an intermediate layer mixture and a release layer mixture; The anti-sticking layer material, the intermediate layer mixed material and the release layer mixed material are melted respectively, and filtered to obtain an anti-sticking layer melt, an intermediate layer melt and a release layer melt; The anti-sticking layer melt, the middle layer melt and the release layer melt are extruded and cooled by a three-layer co-extrusion film blowing unit to obtain a protective film semi-finished product; The protective film semi-finished product is stretched to obtain a photosensitive dry film protective film.

[0015] The materials of each layer of the present invention are based on polyethylene, have good compatibility, are efficiently prepared through a co-extrusion process, and reduce production costs.

[0016] The filtration includes at least two or more stages of filtration, the first stage filtration is 30μm-60μm, and the second and higher stages filtration are 3μm-30μm. The present invention removes impurities and gel point in the raw materials through multi-stage filtration, so that each raw material can meet the requirements of low crystal point.

[0017] The melting temperature is 150°C-180°C.

[0018] The extrusion die head heating temperature is 170°C-190°C.

[0019] The stretching ratio is 2%-5%, and the stretching is performed at a temperature of 120°C-140°C.

[0020] A third aspect of the present invention provides the use of the above-mentioned photosensitive dry film protective film in the production, transportation and storage of photosensitive dry films.

[0021] The present invention has the following beneficial effects: It utilizes ordinary polyethylene as the primary raw material and utilizes nanosilica as a nucleating agent to achieve crystallization point control. It also strictly controls the antioxidant content to minimize its impact on photosensitive dry films. At low concentrations, it achieves long-lasting antioxidant protection through a combination of a specific hindered phenol antioxidant and a phosphite antioxidant. The present invention's photosensitive dry film protective film combines high performance with minimal contamination, meeting the stringent requirements for dry film protective films in high-end electronics manufacturing. DETAILED DESCRIPTION

[0022] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content of the present invention record, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the application's appended claims.

[0023] The reagents / raw materials involved in the examples and comparative examples include: Low-density polyethylene: Dow Chemical, LDPE; Linear low-density polyethylene: Dow, LLDPE; Ethylene vinyl acetate copolymer: Dow, Elvax EVA 250; Nano-silicon dioxide: Changzhou Konada New Materials; Silicone powder: Dongguan Xingyuan Chemical Co., Ltd., XY1065; Hindered phenolic antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]: BASF, Irganox 1010; Phosphite antioxidant tris(2,4-di-tert-butylphenyl)phosphite: BASF, Irgafos 168; 2,6-di-tert-butyl-p-cresol: Shanghai Darui Chemical; Talc: Liaoning Beihai Industry.

[0024] Example 1 A photosensitive dry film protective film, comprising an anti-sticking layer, an intermediate layer and a release layer; The anti-sticking layer is a first low-density polyethylene, and the haze of the first low-density polyethylene is 10%; The release layer includes a first linear low-density polyethylene and silicone powder, and the mass ratio of the first linear low-density polyethylene to the silicone powder is 100:2; The middle layer includes polyethylene, nano-silica and an antioxidant. The polyethylene includes a second low-density polyethylene and a second linear low-density polyethylene. The mass ratio of the second low-density polyethylene to the second linear low-density polyethylene is 40:60. The mass ratio of polyethylene to nano-silica is 100:0.5. The average particle size of the nano-silica is 20 nm. The antioxidant is obtained by compounding Irganox 1010 and Irgafos 168 in a mass ratio of 1:1, and the content of the antioxidant is 200 ppm.

[0025] The total thickness of the photosensitive dry film protective film is 50 μm, and the thickness ratio of the anti-sticking layer, the intermediate layer and the release layer is 20:60:20.

[0026] The preparation method is as follows: Prepare a first low-density polyethylene to obtain a release layer material; mix a second low-density polyethylene, a second linear low-density polyethylene, nano-silica, Irganox 1010 and Irgafos to obtain an intermediate layer mixture; Mixing the first linear low-density polyethylene and silicone powder to obtain a release layer mixture; The anti-sticking layer material, the intermediate layer mixed material and the release layer mixed material are melted respectively, and filtered to obtain an anti-sticking layer melt, an intermediate layer melt and a release layer melt; The anti-sticking layer melt, the middle layer melt and the release layer melt are extruded and cooled by a three-layer co-extrusion film blowing unit to obtain a protective film semi-finished product; The protective film semi-finished product is stretched to obtain a photosensitive dry film protective film.

[0027] The filtration was performed through a primary filtration of 30 μm and a secondary filtration of 3 μm, the melting temperature was 160° C., the extrusion die heating temperature was 180° C., the stretching ratio was 5%, and the stretching was performed at a temperature of 120° C.

[0028] Example 2 A photosensitive dry film protective film, comprising an anti-sticking layer, an intermediate layer and a release layer; The anti-sticking layer is a first low-density polyethylene, and the haze of the first low-density polyethylene is 30%; The release layer includes a first linear low-density polyethylene and silicone powder, and the mass ratio of the first linear low-density polyethylene to the silicone powder is 100:3; The middle layer includes polyethylene, nano-silica and an antioxidant. The polyethylene includes a second low-density polyethylene and a second linear low-density polyethylene. The mass ratio of the second low-density polyethylene to the second linear low-density polyethylene is 50:50. The mass ratio of polyethylene to nano-silica is 100:1. The average particle size of the nano-silica is 30 nm. The antioxidant is obtained by compounding Irganox 1010 and Irgafos 168 in a mass ratio of 1:1, and the content of the antioxidant is 200 ppm.

[0029] The total thickness of the photosensitive dry film protective film is 45 μm, and the thickness ratio of the anti-sticking layer, the intermediate layer and the release layer is 20:65:15.

[0030] The preparation method is as follows: preparing a first low-density polyethylene to obtain an anti-sticking layer material; The second low-density polyethylene, the second linear low-density polyethylene, nano-silica, Irganox 1010 and Irgafos are mixed to obtain an intermediate layer mixture; Mixing the first linear low-density polyethylene and silicone powder to obtain a release layer mixture; The anti-sticking layer material, the intermediate layer mixed material and the release layer mixed material are melted respectively, and filtered to obtain an anti-sticking layer melt, an intermediate layer melt and a release layer melt; The anti-sticking layer melt, the middle layer melt and the release layer melt are extruded and cooled by a three-layer co-extrusion film blowing unit to obtain a protective film semi-finished product; The protective film semi-finished product is stretched to obtain a photosensitive dry film protective film.

[0031] The filtration was performed through a primary filtration of 50 μm and a secondary filtration of 10 μm, the melting temperature was 180° C., the extrusion die heating temperature was 190° C., the stretching ratio was 3%, and the stretching was performed at a temperature of 130° C.

[0032] Example 3 A photosensitive dry film protective film, comprising an anti-sticking layer, an intermediate layer and a release layer; The anti-sticking layer is a first low-density polyethylene, and the haze of the first low-density polyethylene is 20%; The release layer includes a first linear low-density polyethylene and silicone powder, and the mass ratio of the first linear low-density polyethylene to the silicone powder is 100:1.5; The middle layer includes polyethylene, nano-silica and an antioxidant. The polyethylene includes a second low-density polyethylene and a second linear low-density polyethylene. The mass ratio of the second low-density polyethylene to the second linear low-density polyethylene is 30:70. The mass ratio of polyethylene to nano-silica is 100:0.8. The average particle size of the nano-silica is 50 nm. The antioxidant is obtained by compounding Irganox 1010 and Irgafos 168 in a mass ratio of 1:1, and the content of the antioxidant is 100 ppm.

[0033] The total thickness of the photosensitive dry film protective film is 19μm, and the thickness ratio of the anti-sticking layer, the intermediate layer and the release layer is 15:70:15.

[0034] The preparation method is as follows: preparing a first low-density polyethylene to obtain an anti-sticking layer material; The second low-density polyethylene, the second linear low-density polyethylene, nano-silica, Irganox 1010 and Irgafos are mixed to obtain an intermediate layer mixture; Mixing the first linear low-density polyethylene and silicone powder to obtain a release layer mixture; The anti-sticking layer material, the intermediate layer mixed material and the release layer mixed material are melted respectively, and filtered to obtain an anti-sticking layer melt, an intermediate layer melt and a release layer melt; The anti-sticking layer melt, the middle layer melt and the release layer melt are extruded and cooled by a three-layer co-extrusion film blowing unit to obtain a protective film semi-finished product; The protective film semi-finished product is stretched to obtain a photosensitive dry film protective film.

[0035] The filtration was performed through a primary filtration of 40 μm and a secondary filtration of 5 μm, the melting temperature was 170° C., the extrusion die heating temperature was 180° C., the stretching ratio was 2%, and the stretching was performed at a temperature of 130° C.

[0036] Example 4 A photosensitive dry film protective film, comprising an anti-sticking layer, an intermediate layer and a release layer; The anti-sticking layer is a first low-density polyethylene, and the haze of the first low-density polyethylene is 20%; The release layer includes a first linear low-density polyethylene and silicone powder, and the mass ratio of the first linear low-density polyethylene to the silicone powder is 100:3; The middle layer includes polyethylene, nano-silica and an antioxidant. The polyethylene includes a second low-density polyethylene and a second linear low-density polyethylene. The mass ratio of the second low-density polyethylene to the second linear low-density polyethylene is 45:55. The mass ratio of polyethylene to nano-silica is 100:0.5. The average particle size of the nano-silica is 10 nm. The antioxidant is obtained by compounding Irganox 1010 and Irgafos 168 in a mass ratio of 1:1, and the content of the antioxidant is 50 ppm.

[0037] The total thickness of the photosensitive dry film protective film is 17 μm, and the thickness ratio of the anti-sticking layer, the intermediate layer and the release layer is 15:65:20.

[0038] The preparation method is as follows: preparing a first low-density polyethylene to obtain an anti-sticking layer material; The second low-density polyethylene, the second linear low-density polyethylene, nano-silica, Irganox 1010 and Irgafos are mixed to obtain an intermediate layer mixture; Mixing the first linear low-density polyethylene and silicone powder to obtain a release layer mixture; The anti-sticking layer material, the intermediate layer mixed material and the release layer mixed material are melted respectively, and filtered to obtain an anti-sticking layer melt, an intermediate layer melt and a release layer melt; The anti-sticking layer melt, the middle layer melt and the release layer melt are extruded and cooled by a three-layer co-extrusion film blowing unit to obtain a protective film semi-finished product; The protective film semi-finished product is stretched to obtain a photosensitive dry film protective film.

[0039] The filtration was performed through a primary filtration of 20 μm and a secondary filtration of 5 μm, the melting temperature was 180° C., the extrusion die heating temperature was 180° C., the stretching ratio was 4%, and the stretching was performed at a temperature of 140° C.

[0040] Example 5 A photosensitive dry film protective film, comprising an anti-sticking layer, an intermediate layer and a release layer; The anti-sticking layer is a first low-density polyethylene, and the haze of the first low-density polyethylene is 20%; The release layer includes a first linear low-density polyethylene and silicone powder, and the mass ratio of the first linear low-density polyethylene to the silicone powder is 100:1; The middle layer includes polyethylene, nano-silica and an antioxidant. The polyethylene includes a second low-density polyethylene and a second linear low-density polyethylene. The mass ratio of the second low-density polyethylene to the second linear low-density polyethylene is 35:65. The mass ratio of polyethylene to nano-silica is 100:0.5. The average particle size of the nano-silica is 20 nm. The antioxidant is obtained by compounding Irganox 1010 and Irgafos 168 in a mass ratio of 1:1, and the content of the antioxidant is 50 ppm.

[0041] The total thickness of the photosensitive dry film protective film is 5 μm, and the thickness ratio of the anti-sticking layer, the intermediate layer and the release layer is 20:60:20.

[0042] The preparation method is as follows: preparing a first low-density polyethylene to obtain an anti-sticking layer material; The second low-density polyethylene, the second linear low-density polyethylene, nano-silica, Irganox 1010 and Irgafos are mixed to obtain an intermediate layer mixture; Mixing the first linear low-density polyethylene and silicone powder to obtain a release layer mixture; The anti-sticking layer material, the intermediate layer mixed material and the release layer mixed material are melted respectively, and filtered to obtain an anti-sticking layer melt, an intermediate layer melt and a release layer melt; The anti-sticking layer melt, the middle layer melt and the release layer melt are extruded and cooled by a three-layer co-extrusion film blowing unit to obtain a protective film semi-finished product; The protective film semi-finished product is stretched to obtain a photosensitive dry film protective film.

[0043] The filtration was performed through a primary filtration of 30 μm and a secondary filtration of 3 μm, the melting temperature was 160° C., the extrusion die heating temperature was 180° C., the stretching ratio was 2%, and the stretching was performed at a temperature of 130° C.

[0044] Comparative Example 1 A protective film is different from Example 1 only in that the antioxidant is 2,6-di-tert-butyl-p-cresol.

[0045] Comparative Example 2 A protective film, which is different from Example 1 only in that the antioxidant content is 500 ppm.

[0046] Comparative Example 3 A protective film, which differs from Example 1 only in that the intermediate layer does not include nano-silicon dioxide.

[0047] Comparative Example 4 A protective film, the only difference from Example 1 is that the haze of the first low-density polyethylene of the anti-sticking layer is 9%.

[0048] Comparative Example 5 A protective film is different from Example 1 only in that the anti-sticking layer comprises a first low-density polyethylene and talc, and the mass ratio of the first low-density polyethylene to the talc is 100:5.

[0049] The tests of the relevant properties of the products in the examples and comparative examples of this application are as follows: Crystal point control: Cut a 30cm×30cm sample from the photosensitive dry film protective film product, lay it flat on the observation table, and inspect the crystal points one by one with the naked eye at a distance of 50cm from the sample. Count the number of crystal points per unit area and record the size range. Tensile strength: in accordance with GB / T 1040.3-2006 Plastics - Determination of tensile properties - Part 3: Test conditions for thin plastics and sheets; Tensile strength retention rate: The sample was aged in an oven at 80°C for 7 days to test its tensile strength, and the tensile strength retention rate was calculated based on the tensile strength before and after aging; Haze: in accordance with GB / T 2410-2008 Determination of light transmittance and haze of transparent plastics; Anti-sticking layer rewinding quality test: rewind the finished product with a width of 1800mm, ≥5000m / roll, and check the rewinding quality of the parent roll to see if there is any adhesion between the film layers; Photosensitive dry film contamination: Prepare the protective film into a photosensitive dry film and test the sensitivity of the photosensitive adhesive. The standard is sensitivity change ≤±2.

[0050] Table 1 Test results of the photosensitive dry film protective film prepared in the examples of this application Table 2 Test results of the photosensitive dry film protective film prepared in the comparative example of this application Referring to the test data shown in Tables 1 and 2, compared to Example 1, Comparative Example 1 employs the conventional antioxidant 2,6-di-tert-butyl-p-cresol. When its content is ≤200 ppm, the tensile strength retention of the product is significantly reduced, indicating that conventional 2,6-di-tert-butyl-p-cresol antioxidants cannot guarantee antioxidant effectiveness at low levels. Comparative Example 2, compared to Example 1, increases the content of the hindered phenol antioxidant and phosphite antioxidant combination to 500 ppm. The tensile strength retention is only slightly improved, with no significant improvement in antioxidant effectiveness. However, the sensitivity of the photosensitive dry film adhesive measured in Comparative Example 2 decreases significantly during application, indicating the risk of antioxidant migration. Comparative Example 3, compared to Example 1, shows that the absence of nano-silica produces a significant number of large crystals. Comparative Example 4, compared to Example 1, shows that using low-density polyethylene with a haze of less than 10% as the release layer results in a product with low haze and an overly smooth surface, resulting in film sticking during winding and poor winding quality. Comparing Comparative Example 5 with Example 1, it can be seen that the addition of talcum powder to the anti-sticking layer significantly reduces the sensitivity of the product. This may be because the talcum powder is transferred to the photosensitive adhesive, affecting the performance of the photosensitive adhesive.

[0051] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and supplements without departing from the method of the present invention. These improvements and supplements should also be regarded as the scope of protection of the present invention.

Claims

1. A photosensitive dry film protective film, characterized in that: It includes an anti-sticking layer, an intermediate layer and a release layer, wherein the anti-sticking layer is a first low-density polyethylene, and the haze of the first low-density polyethylene is 10%-30%; The release layer includes a first linear low-density polyethylene and a release agent; The middle layer includes polyethylene, nano-silica and an antioxidant. The polyethylene includes a second low-density polyethylene and a second linear low-density polyethylene. The antioxidant is obtained by compounding a hindered phenol antioxidant and a phosphite antioxidant. The content of the antioxidant is ≤200ppm.

2. The photosensitive dry film protective film according to claim 1, characterized in that: The mass ratio of the second low-density polyethylene to the second linear low-density polyethylene is (30-50):(60-80).

3. The photosensitive dry film protective film according to claim 1, characterized in that: The mass ratio of the polyethylene to the nano-silicon dioxide is 100:(0.5-1), and the average particle size of the nano-silicon dioxide is 5nm-50nm.

4. The photosensitive dry film protective film according to claim 1, characterized in that: The mass ratio of the hindered phenol antioxidant to the phosphite antioxidant is 1:1, the hindered phenol antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and the phosphite antioxidant is tris(2,4-di-tert-butylphenyl)phosphite.

5. The photosensitive dry film protective film according to claim 1, characterized in that: The mass ratio of the first linear low-density polyethylene to the release agent is 100:(1-3), and the release agent is silicone powder.

6. The photosensitive dry film protective film according to claim 1, characterized in that: The total thickness of the photosensitive dry film protective film is 5 μm-50 μm, and the thickness ratio of the anti-sticking layer, the intermediate layer and the release layer is (15-25):(50-70):(15-25).

7. A method for preparing a photosensitive dry film protective film according to any one of claims 1 to 6, characterized in that: The following steps are involved: preparing the raw material of the anti-sticking layer to obtain an anti-sticking layer material; respectively mixing the raw materials of the intermediate layer and the release layer to obtain an intermediate layer mixture and a release layer mixture; The anti-sticking layer material, the intermediate layer mixed material and the release layer mixed material are melted respectively, and filtered to obtain an anti-sticking layer melt, an intermediate layer melt and a release layer melt; The anti-sticking layer melt, the intermediate layer melt and the release layer melt are extruded and cooled by a three-layer co-extrusion film blowing unit to obtain a protective film semi-finished product; The protective film semi-finished product is stretched to obtain the photosensitive dry film protective film.

8. The method for preparing a photosensitive dry film protective film according to claim 7, characterized in that: The filtration includes at least two levels of filtration, the first level filtration is 30 μm-60 μm, and the second level and above filtration is 3 μm-30 μm.

9. The method for preparing a photosensitive dry film protective film according to claim 7, wherein: The melting temperature is 150-180°C; and / or the extrusion die head heating temperature is 170-190°C; and / or the stretching ratio is 2%-5%, and the stretching is performed at a temperature of 120-140°C.

10. Use of the photosensitive dry film protective film according to any one of claims 1 to 6 in the production, transportation and storage of photosensitive dry films.

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