KR101118872B1 - Surface protecting film and surface protecting material using the same - Google Patents

Abstract

The surface protective film of the present invention is formed of an ionizing radiation curable resin composition, an isocyanate prepolymer and a releasing agent. Preferably, the releasing agent has a silicon content of 50% by weight to 90% by weight, a number average molecular weight of 5000 to 20000, and an acrylic It is silicone acrylate whose number of rate functional groups is three or more. The surface protective film is not eroded by cleaning with a cleaning solvent, and is not eroded even by a solvent such as a polyhydric alcohol or a derivative thereof contained in the photoresist, so that very high releasability to the photoresist is maintained.

Surface protection film, surface protection material, photomask, photoresist, release property

Description

Surface protective film and surface protecting material using the same

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to surface protective films and surface protective materials having releasability. In particular, the present invention relates to a surface of a document (photomask) when exposing a photoresist having adhesive properties to a printed board manufacturing process or the like. The present invention relates to a surface protective film and a surface protective material suitably used.

Usually, a printed wiring board and a resin convex board are produced by bringing a photomask (exposure document) into close contact with an adhesive photoresist such as a liquid photoresist. When the photomask is peeled from the photoresist after the end of the exposure, in order to prevent a portion of the photoresist from adhering to the surface of the photomask, a surface protective material having releasability on the surface facing the photoresist on the conventional photomask (surface protection Sheet).

As such a surface protection material for photomasks, it is proposed to have a surface protective film which has releasability on one side of a plastic film, and to have an adhesive layer on the other side (Japanese Patent Laid-Open No. 11-13). See publication 7121). However, even in such a surface protection material, adhesion of the photoresist to the surface protection film is not completely prevented, and the surface of the surface protection film is cleaned with a cleaning solvent in order to remove photoresist or other dust remaining on the surface protection film. Cleaning (wiping operation) is performed regularly. For this reason, such a surface protection material is required to keep releasability to prevent adhesion of a resist even after cleaning.

On the other hand, the surface protection material which maintains mold release property with respect to a photoresist even after cleaning with a cleaning solvent is proposed (Japanese Patent Laid-Open No. 2000-273412). As such a surface protection material, sufficient releasability could be sustained with respect to cleaning by the cleaning solvents, such as a lower alcohol. However, in recent years, as a method of applying photoresist, a method such as spray coat or curtain coat has been taken from conventional screen printing in order to increase mass productivity. Therefore, the component and content of the solvent contained in the photoresist are changed, and the surface protective film is gradually eroded by a solvent such as a polyhydric alcohol or a derivative thereof contained in the photoresist, so that sufficient release property to the photoresist can be maintained. It became impossible.

On the other hand, since the surface protection material used for the surface of the photomask has irregularities due to through holes or the like on the substrate, such as a printed wiring board, the convex portion is subjected to a higher pressure than the smooth portion during close exposure. There is also a problem that the surface protective film is cut little by little every time the exposure is repeated.

Therefore, in the present invention, the surface protective film is not eroded by cleaning with a cleaning solvent, and is not eroded by a solvent such as a polyhydric alcohol or a derivative thereof contained in the photoresist, so that very high releasability of the photoresist is maintained. It is an object to provide a surface protective film and a surface protective material using the same.

Moreover, even if it uses repeatedly, an object of this invention is to prevent the fall of the release property of a surface protection film by physically scraping off a surface protection film, to suppress a rise of a haze, and to prevent the fall of resolution.

The surface protection film of this invention which achieves the said objective is a surface protection film which has releasability, It is characterized by being formed from an ionizing radiation curable resin composition and an isocyanate prepolymer.

The surface protective film of the present invention is characterized in that it is formed of an ionizing radiation curable resin composition, an isocyanate prepolymer, and a release agent.

In the surface protective film of the present invention, the content of the isocyanate prepolymer is not particularly limited, but is preferably 1% by weight or more and 50% by weight or less of the total resin solid content constituting the surface protection film.

In the surface protective film of this invention, mold release property can be provided by the mold release component or mold release agent contained in an ionizing radiation curable resin composition, for example.

The mold release agent is preferably a silicone compound. The silicone compound is preferably silicone acrylate. The silicone acrylate preferably has a silicon content of 50% by weight or more and 90% by weight or less, a number average molecular weight of 5000 to 20000, and a number of acrylate functional groups of 3 or more. The silicon content rate referred to in the present invention refers to the proportion of the polyalkylsiloxane skeleton in silicon acrylate.

The surface protection material of this invention has the surface protection film mentioned above on one side of a plastic film, and has an adhesive layer on the other side. It is characterized by the above-mentioned.

The surface protective film and the surface protective material of the present invention contain an isocyanate prepolymer together with an ionizing radiation curable resin composition so that the surface protective film is not eroded by cleaning with a cleaning solvent, and furthermore, a polyhydric alcohol or a derivative thereof contained in a photoresist. It does not corrode even by the solvent used, etc., and can maintain a very high mold release property with respect to a photoresist.

In the present invention, by using the ionizing radiation curable resin composition as the resin component constituting the surface protective film, it is possible to make the surface protective film difficult to be cut even if the exposure is repeated. Thereby, the fall of mold release property can be prevented, the rise of a haze can be suppressed, and the fall of a resolution can be prevented. In addition, since the surface protective film is less likely to be scratched, the durability of the surface protective film is improved, and the number of times of exposure can be significantly increased.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of each component of the surface protection film of this invention is described.

The ionizing radiation curable resin composition constituting the surface protective film of the present invention is a material which can be crosslinked and cured by irradiation with ionizing radiation (ultraviolet rays or electron beams), and the mechanical strength and haze of the surface protective film after curing. To prevent degradation. The hardness of the surface protective film varies depending on the laminated body, but the haze difference before and after the taper wear hardness test according to JIS K5400: 1990 (that is, the taper from the haze after the taper wear hardness test). The value obtained by subtracting the haze before the wear hardness test, hereinafter abbreviated as "ΔH") is preferably less than 25 and further less than 20.

As the ionizing radiation curable resin composition, a photopolymerizable prepolymer can be used. As this photopolymerizable prepolymer, the acrylic prepolymer which has a 2 or more acryloyl group in 1 molecule, and becomes a three-dimensional network structure by crosslinking hardening is used especially preferably. Urethane acrylate, polyester acrylate, epoxy acrylate, melamine acrylate, polyfluoroalkyl acrylate, silicone acrylate, etc. can be used as this acryl-type prepolymer. In addition, although these acrylic prepolymers can be used independently, it is preferable to add a photopolymerizable monomer in order to improve crosslinking curability and to improve the hardness of a surface protective film further.

Examples of the photopolymerizable monomer include monofunctional acrylic monomers such as 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and butoxyethyl acrylate, 1,6-hexanediol diacrylate, and neo Bifunctional acryl monomers such as pentyl glycol diacrylate, diethylene glycol diacrylate, polyethylene glycol diacrylate, hydroxypivaric acid ester neopentyl glycol diacrylate, dipentaerythritol hexaacrylate, trimethylpropane triacrylate And one or two or more kinds of polyfunctional acrylic monomers such as pentaerythritol triacrylate and the like are used.

It is preferable to use additives, such as a photoinitiator and a photoinitiator, when a surface protection film is hardened | cured by ultraviolet irradiation other than the photopolymerizable prepolymer and photopolymerizable monomer mentioned above.                     

Examples of the photopolymerization initiator include acetophenone, benzophenone, Michler's ketone, benzoin, benzyl methyl ketal, benzoyl benzoate, α-acyloxymester, thioxanthones, and the like.

In addition, the photopolymerization accelerator can reduce the polymerization impairment caused by air during curing and increase the curing speed. Examples thereof include p-dimethylamino benzoic acid isoamyl ester and p-dimethylamino benzoic acid ethyl ester. have.

Next, the isocyanate prepolymer which comprises the surface protection film of this invention with the ionizing radiation curable resin composition mentioned above is demonstrated. The isocyanate prepolymer referred to herein refers to an isocyanate prepolymer which is usually used in a room temperature curing system together with a polyol resin. Isocyanate prepolymers include tolylene diisocyanate type, diphenylmethane diisocyanate type, xylylene diisocyanate type, isophorone diisocyanate type, hexamethylene diisocyanate type, etc. with raw material isocyanate. Xylylene diisocyanate type, an isophorone diisocyanate type, and a hexamethylene diisocyanate type are used suitably from a viewpoint of a weather resistance and weather resistance.

By crosslinking and curing such an isocyanate prepolymer with an ionizing radiation curable resin composition, release property can be continued in a surface protection film. The reason why the release property can be continued by containing the isocyanate prepolymer together with the ionizing radiation curable resin composition is not necessarily clear, but it can be considered as follows. That is, hardening impairment caused by oxygen in the air and hardening impairment caused by a releasing agent are occurring at the surface of the film, and solvent resistance is deteriorated by this. It is considered that the polymer is able to compensate for the lack of crosslinking caused by crosslinking reaction and curing failure. It is thought that the surface protection film improves solvent resistance and can maintain mold release property by this, compared with the thing which does not contain an isocyanate prepolymer. In addition, by irradiating ionizing radiation in an atmosphere of an inert gas or the like, it is possible to prevent such hardening obstacles caused by oxygen in the air. However, in such a method, it is expensive to equip equipment and hardening obstacles by a release agent. It cannot be prevented.

The said effect is acquired by containing a small amount of isocyanate prepolymers, and the content is not specifically limited. In addition, since it varies depending on the content of the isocyanate group, the thickness of the surface protective film and the addition amount of the release agent, it cannot be said uniformly. It is made into% or more, More preferably, it is 10 weight% or more, As an upper limit, it is 50 weight% or less, Preferably you may be 30 weight% or less. The film hardness obtained by using an ionizing radiation curable resin composition by using 1% by weight or more of the isocyanate prepolymer crosslinking reaction on the surface of the surface protective film to compensate for the lack of crosslinking caused by curing failure. Physical properties such as can be prevented from being lost.

Next, the component which gives a release property to the surface protection film of this invention is demonstrated.                     

It does not specifically limit as a mold release agent, The mold release agent using a fluorine compound and a silicone type compound can be used, In consideration of the initial mold release property from a photoresist, it is preferable that it is a silicone type compound. Examples of such silicone compounds include silicone oils, silicone resins, ladder polymers of organosyl sesquioxanes, silicone comb graft polymers, silicone acrylates, and the like, with the ionizing radiation curable resin compositions described above. It is preferable to use silicone acrylate from the thing which can be bridge | crosslinked.

In addition, when the above-mentioned polyfluoroalkyl acrylate and silicone acrylate are used alone as a photopolymerizable prepolymer, mold release property can be imparted to the surface protective film without using a releasing agent described later, but these photopolymerizable prepolymers It is preferable to use together with the other ionizing radiation curable resin composition mentioned above as a mold release agent rather than using alone.

It is preferable to use a silicone acrylate as a mold release agent especially from a viewpoint of adhesiveness with a laminated body when it is used as a surface protective film, surface hardness, initial mold release property, and the continuation of mold release after repeated exposure and cleaning. When silicone acrylate is used as a releasing agent, the surface hardness is increased by another ionizing radiation curable resin composition, and the silicone acrylate has a specific silicone content so that sufficient release property can be obtained even with a small amount of addition. It is preferable to make a number average molecular weight and the number of acrylate functional groups a thing from a viewpoint of the persistence of mold release property after repeating cleaning.                     

That is, such silicone acrylate has a silicon content of at least 50 wt%, preferably at least 60 wt%, and at most 90 wt%, preferably at most 80 wt% as the upper limit. When the silicon content is at least 50% by weight, excellent mold release property can be imparted, and when the silicone content is at most 90% by weight, effective number of acrylate functional groups can be imparted to maintain mold release property.

Moreover, it is preferable that a number average molecular weight is 5000-20000, Furthermore, it is preferable that it is 10000-15000. By setting the number average molecular weight to 5000 or more, it is possible to prevent the release agent from being transferred to the photoresist side at the time of exposure, and by setting it as 20000 or less, the compatibility with the above-mentioned ionizing radiation curable resin composition is prevented from being lowered and the transparency of the film is prevented. At the same time, release of the surface protective film can be continued.

Moreover, it is preferable that it is three or more, and, as for the number of acrylate functional groups, it is more preferable that it is three or more and eight or less. By setting the number of acrylate functional groups to 3 or more, the reactivity with the above-mentioned ionizing radiation curable resin composition is sufficient, and releasability can be continued. Moreover, even if the number of acrylate functional groups is 8 or more, since the continuation of releasability by improvement of the reactivity with the ionizing radiation curable resin composition mentioned above cannot be expected, it is preferable to set it as such a range.

Although the addition amount of such a mold release agent changes with kinds of mold release agents used, such as a fluorine compound or a silicone type compound, in the case of a silicone type compound, it is generally about 0.1 weight%-20 weight% in the total resin solid content which comprises a surface protective film. Moreover, when using a silicone acrylate, although it changes also with a silicon content rate, it is preferable to set it as about 0.5 to 10 weight%, Furthermore, about 0.5 to 5 weight% in the said range.

The surface protection film of this invention may mix other resin as long as it is a range which does not impair these effects other than the ionizing radiation curable resin composition mentioned above, the isocyanate prepolymer and the mold release agent added as needed. However, in the case of the resin which will react with the isocyanate prepolymer, such as polyol resin, it is necessary to increase the amount of the isocyanate prepolymer added as much as the reaction. In addition, the surface protective film may contain lubricants, fine particles, fluorescent brighteners, pigments, antistatic agents, flame retardants, antimicrobial agents, mold mildews, antioxidants, plasticizers, leveling agents, and flow regulators so long as they do not impair these effects. Various additives, such as an antifoamer and a dispersing agent, can be included.

In particular, as a surface protective film for photomasks, it is preferable to form fine irregularities on the surface of the surface protective film by containing fine particles such as inorganic pigments, resin beads, etc. in the surface protective film from the viewpoint of facilitating vacuuming during close exposure. Such fine particles include inorganic pigments such as calcium carbonate, magnesium carbonate, barium sulfate, silica, aluminum hydroxide, kaolin, clay, and talc, acrylic resin particles, polystyrene resin particles, polyurethane resin particles, polyethylene resin particles, and benzoguanamine resins. Resin beads, such as particle | grains and an epoxy resin particle, can be used. Since the addition amount of such microparticles | fine-particles changes with the kind of microparticles | fine-particles and the thickness of a surface protective film, it cannot be said uniformly, Usually, it is about 0.1 to 10 weight% with respect to the total resin solid content which comprises a surface protective film. In addition, since the average particle diameter of such microparticles | fine-particles changes with the thickness of a surface protective film, it cannot be said uniformly, Usually, it is about 0.1 micrometer-10 micrometers, Preferably, 0.5 micrometer-5 micrometers are used.

Although the thickness of a surface protection film is not specifically limited, In order not to reduce the resolution of the photomask at the time of exposure, a thinner side is preferable. In addition, from the viewpoints of surface hardness of the surface protective film, prevention of chipping of the surface protective film by repeating close exposure, initial release and continuation of release after cleaning, a certain thickness is required. Specifically, the thickness is 0.5 µm to 5 µm, preferably 1 µm to 3 µm.

Such a surface protective film is mixed with an ionizing radiation curable resin composition, an isocyanate prepolymer and a release agent added as needed, other resins, other additives and diluting solvents to adjust the coating liquid for the surface protective film, and a conventionally known coating method, for example For example, a bar coater, a die coater, a blade coater, a spin coater, a roll coater, a gravure coater, a flow coater, a spray, a screen print, or the like is applied directly to a photomask or the like to be protected, It can be produced by drying if necessary, curing by irradiation with ionizing radiation, and further curing by heating as necessary.

As a method of irradiating ionizing radiation, ultraviolet rays in a wavelength range of 100 nm to 400 nm, preferably 200 nm to 400 nm emitted from an ultra high pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc, a metal halide lamp, or the like, or The method of irradiating the electron beam of the wavelength range of 100 nm or less emitted from a scanning type or curtain type electron beam accelerator can be employ | adopted.

The surface protective film of the present invention is formed directly on the photomask as described above, and used, for example, on the other surface of the plastic film provided with an adhesive layer on one surface, the surface protective film is formed in the same manner as described above. A protective material can also be produced and used by bonding the surface having the pressure-sensitive adhesive layer of the surface protective film with the surface of the photomask.

Although it does not specifically limit as such a plastic film, It is preferable that transparency is high, and it is more preferable that especially high ultraviolet transmittance used at the time of exposure is high. As such a plastic film, the plastic film which is excellent in transparency, such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyethylene, polypropylene, polystyrene, triacetyl cellulose, acryl, polyvinyl chloride, is used, for example. do. In particular, biaxially stretched polyethylene terephthalate films are suitably used because of their excellent mechanical strength and dimensional stability. Moreover, it is preferable to use the thing in which the adhesion | attachment process was given to the surface. Examples of the easy adhesion treatment include a plasma treatment, a corona discharge treatment, an ultraviolet irradiation treatment, and the formation of an under coating easy adhesion treatment layer.

The thickness of the plastic film is preferably as thin as possible from the viewpoint of not lowering the resolution of the photomask during exposure. However, considering the handleability and mechanical strength, the thickness of the plastic film is preferably 1 μm to 100 μm, preferably 2 μm to 25 μm. Preferably it is about 4 micrometers-15 micrometers.                     

The adhesive layer is formed of at least an adhesive component. It does not specifically limit as an adhesive component, A natural resin adhesive, a synthetic resin adhesive, etc. are used, Synthetic resin adhesives, such as an acrylic adhesive, a silicone adhesive, and a urethane type adhesive, are used preferably. Moreover, as long as it is a range which does not impair adhesiveness, in the adhesion layer, various additives similar to a crosslinking agent and a surface protective film can be included.

Although the thickness of an adhesion layer is not specifically limited, 0.5 micrometer-20 micrometers, Preferably it is 1 micrometer-10 micrometers, More preferably, about 2 micrometers-4 micrometers so that moderate adhesiveness can be obtained without impairing transparency (resolution). do. Moreover, what is necessary is just to bond together the separator which performed the mold release process on the surface of plastic films, paper, etc. so that the adhesiveness may not reduce the handleability of a surface protection material by the adhesiveness.

The pressure-sensitive adhesive layer is prepared by dissolving or dispersing an adhesive component and a crosslinking agent or other additive added as necessary in a solvent to prepare a coating liquid for pressure-sensitive adhesive layer, and the surface protective film of the plastic film described above by a conventionally known coating method similar to the surface protective film described above. It can produce by apply | coating and drying on the surface opposite to the surface which forms the form. Moreover, it can produce by apply | coating and drying the said coating liquid for adhesion layers on a separator etc. to the surface opposite to the surface which forms the surface protection film of a plastic film.

Hereinafter, the present invention will be described in more detail with reference to Examples. In addition, in this Example, "part" and "%" are a basis of weight unless there is particular notice.

Example 1

On one side of a polyethylene terephthalate film (Lumera: Douresha) having a thickness of 6 μm, the coating liquid for the surface protective film of the following prescription was applied sequentially to the other side, and the coating liquid for the adhesive layer of the following prescription was applied and dried, respectively. The surface of the surface forming film was irradiated with ultraviolet light with a high pressure mercury lamp to form a surface protective film having a thickness of 2 m. In addition, the surface having an adhesive layer was bonded with a separator having a thickness of 25 μm (MRB: Mitsubishi Chemical Co., Ltd.) in consideration of handling properties, and cured at 60 ° C. for 2 days to prepare the surface protective material of Example 1. It was. In addition, silicone acrylate a used as a mold release agent was 70% of silicone content, the number average molecular weight was about 12000, and the number of acrylate functional groups was six.

<Prescription of Coating Liquid for Surface Protective Film of Example 1>

16 parts of ionizing radiation curable resin composition

  (Polyester acrylate) (solid content 100%)

  (Aronix M7100: Doago Seisha)

5.5 parts of isocyanate prepolymers (75% solids)

  (Bannock D750: Dainippon Ink and Chemical Industries, Ltd.)

? 0.2 release agents

  (Silicone acrylate a) (100% solids)

Photopolymerization initiator part 1

  Irgacure 184 Sea Specialty Chemicals

Methyl ethyl ketone 77 parts

<Prescription of Coating Liquid for Adhesive Layer>

10 parts of acrylic pressure-sensitive adhesives (40% solids)

  (Arontech SCL-200: Toagosei Chemicals)

Toluene, part 10

10 parts ethyl acetate

[Example 2]

The surface protection material of Example 2 was produced like Example 1 except having changed the coating liquid for surface protection films of Example 1 into the coating liquid for surface protection films of the following prescription. In addition, the silicone acrylate b used as a mold release agent was 20% of silicone content, the number average molecular weight was about 3000, and the number of acrylate functional groups was two.

<Prescription of Coating Liquid for Surface Protective Film of Example 2>

16 parts of ionizing radiation curable resin composition

  (Epoxy acrylate) (100% solids)

  (KAYARAD R130: Nippon Kayakusha)

5.5 parts of isocyanate prepolymers (75% solids)

  (Bannock D750: Dainippon Ink and Chemical Industries, Ltd.)

? 0.2 release agents                     

  (Silicone acrylate b) (100% solids)

Photopolymerization initiator part 1

  Irgacure 184 Sea Specialty Chemicals

Methyl ethyl ketone 77 parts

Example 3

The surface protection material of Example 3 was produced like Example 1 except having changed the coating liquid for surface protection films of Example 1 into the coating liquid for surface protection films of the following prescription. In addition, the silicone oil used as a mold release agent modified | denatured one terminal of polysiloxane with the organic group.

<Prescription of Coating Liquid for Surface Protective Film of Example 3>

16 parts of ionizing radiation curable resin composition

  (Urethane acrylate) (solid content 100%)

  (NK raise UI5HA: Shinnakamura Gakuku High School)

5.5 parts of isocyanate prepolymers (75% solids)

  (Bannock D750: Dainippon Ink and Chemical Industries, Ltd.)

? 0.2 release agents

  (Silicone oil) (solid content 100%)

  (X22-170DX: Shin-Etsu Chemical Co., Ltd.)                     

Photopolymerization initiator part 1

  Irgacure 184 Sea Specialty Chemicals

Methyl ethyl ketone 77 parts

Comparative Example 1

A surface protective material of Comparative Example 1 in the same manner as in Example 1 except that the coating liquid for surface protection film of Example 1 was changed to the coating liquid for surface protection film (without addition of isocyanate prepolymer) of the following prescription. Was produced.

<Prescription of Coating Liquid for Surface Protective Film of Comparative Example 1>

20 parts of ionizing radiation curable resin composition

  (Polyester acrylate) (solid content 100%)

  (Aronix M7100: Doago Seisha)

? 0.2 release agents

  (Silicone acrylate a) (100% solids)

Photopolymerization initiator part 1

  Irgacure 184 Sea Specialty Chemicals

Methyl ethyl ketone 79 parts

Comparative Example 2                     

A surface protective material of Comparative Example 2 in the same manner as in Example 2 except that the coating liquid for surface protective film of Example 2 was changed to the coating liquid for surface protection film (without addition of isocyanate prepolymer) of the following prescription. Was produced.

<Prescription of Coating Liquid for Surface Protective Film of Comparative Example 2>

20 parts of ionizing radiation curable resin composition

  (Epoxy acrylate) (100% solids)

  (KAYARAD R130: Nippon Kayakusha)

? 0.2 release agents

  (Silicone acrylate b) (100% solids)

Photopolymerization initiator part 1

  Irgacure 184 Sea Specialty Chemicals

Methyl ethyl ketone 79 parts

Comparative Example 3

A surface protective material of Comparative Example 3 was prepared in the same manner as in Example 3 except that the coating liquid for surface protection film of Example 3 was changed to the coating liquid for surface protection film (without addition of isocyanate prepolymer) of the following prescription. Produced.

<Prescription of Coating Liquid for Surface Protective Film of Comparative Example 3>                     

20 parts of ionizing radiation curable resin composition

  (Urethane acrylate) (solid content 100%)

  (NK raise UI5HA: Shinnakamura Gakuku High School)

? 0.2 release agents

  (Silicone oil) (solid content 100%)

  (X22-170DX: Shin-Etsu Chemical Co., Ltd.)

Photopolymerization initiator part 1

  Irgacure 184 Sea Specialty Chemicals

Methyl ethyl ketone 79 parts

With respect to the surface protective material obtained in Examples and Comparative Examples, whether the surface protective film is not eroded even by cleaning with a cleaning solvent or a solvent such as a polyhydric alcohol contained in the photoresist, and whether or not high releasability is maintained with respect to the photoresist. Was evaluated by performing the following test. Moreover, the wear resistance of the surface protection film was evaluated by repeatedly exposing. Table 1 shows the evaluation results.

(1) Evaluation of Initial Dysplasia

An adhesive tape (Nitto Polyester 31b: Nitto Denko Co., Ltd.) was affixed on a surface having a surface protective film of the surface protective materials of Examples 1 to 3 and Comparative Examples 1 to 3, and a tensile tester (TENSILON HTM) -100: Toyoboldwinsha), 180 degree peeling force in peeling speed of 300 mm / min was measured and evaluated. The evaluation used "(circle)" and 20 g / 50mm-30 g / 50mm of peeling force which was less than 20g / 50mm, and made "x" that there was a sticky feeling by "(circle)" and uncured.

(2) Evaluation of release property after wiping test

As a wiping test, the surface having the surface protective film of the surface protective materials of Examples 1 to 3 and Comparative Examples 1 and 2 was immersed in gauze with ethyl alcohol (EtOH) as a cleaning solvent, and then the releasability after 50 wiping operations was performed. Measurement was carried out in the same manner as the initial release. In addition, in order to evaluate the solvent resistance with respect to the polyhydric alcohol contained in a photoresist, the wiping test was done similarly to the above using propylene glycol monomethyl ether (PGM) instead of ethyl alcohol (EtOH). The evaluation used "(circle)" and the thing which became 10 times or more "(circle)" and the thing which was 2 times or more and less than 10 times that peeling force was less than 2 times the initial measured value as "x".

(3) evaluation of wear resistance

After peeling the separator of the surface protection material of Examples 1-3 and Comparative Examples 1 and 2, bonding it to a transparent polyethylene terephthalate film (188 micrometers in thickness), it was a wear ring based on JISK5400: 1990. A taper abrasion test was performed at CS-10F, a load of 500 g, a rotational speed of 70 rpm, and a rotational speed of 100 cycles, and the value obtained by subtracting the haze before the test (initial haze) from the haze after the test was taken as the taper wear hardness ΔH. In addition, haze was measured using the haze meter (NDH2000: Nippon Denshokusha) based on JISK7136: 2000. Evaluation made "(circle)" that ΔH was less than 20.

As is apparent from the results in Table 1, the surface protective materials of Examples 1 to 3 are used as cleaning agents for cleaning the surface protective film since the surface protective film is formed of an ionizing radiation curable resin composition, an isocyanate prepolymer and a release agent. In addition to excellent solvent resistance to phosphorus ethyl alcohol, it also had excellent solvent resistance to propylene glycol monomethyl ether which is a polyhydric alcohol contained in the photoresist.

In particular, the surface protective material of Example 1 used a silicone acrylate having a silicon content of 70% by weight, a number average molecular weight of about 12000 and an acrylate functional group of 6 as the surface protective film as a release agent, and thus exhibited excellent releasability even after the wiping test. It became to last.

On the other hand, since the surface protective film of Comparative Example 1 was formed without containing an isocyanate prepolymer, the duration of this formation after the wiping test was inferior to that of Example 1.

In addition, since the surface protective film of Example 2 used a silicone acrylate having a silicon content of 20% by weight, a number average molecular weight of about 3000 and an acrylate functional group of 2 as the surface protective film as a release agent, good releasability was obtained even after the wiping test. It became to last. On the other hand, since the surface protective film of Comparative Example 2 was formed without containing an isocyanate prepolymer, the sustainability of releasability after the wiping test was inferior to that of Example 2.

In addition, although the surface protective film of Example 3 used the silicone oil as a mold release agent, but since the surface protective film was formed containing an isocyanate prepolymer, initial release property became favorable and it became favorable to maintain good mold release property even after a wiping test. On the other hand, since the surface protective material of Comparative Example 3 was formed without containing an isocyanate prepolymer, the surface protective film caused hardening impairment by silicone oil and became unsticky and gooey.

According to the present invention, the surface protective film having a releasability formed of an ionizing radiation curable resin composition and an isocyanate prepolymer is used to prevent exposure and cleaning without being eroded by cleaning by a cleaning solvent or by a solvent contained in a photoresist. Even if it is performed repeatedly, the surface protection film and surface protection film which maintain high release property can be obtained.

Claims (9)

Release property characterized in that it is formed of an ionizing radiation curable resin composition containing an acrylic prepolymer having two or more acryloyl groups in one molecule and crosslinking with ionizing radiation to form a three-dimensional network structure and an isocyanate prepolymer. Having a surface protective film. An ionizing radiation curable resin composition comprising an acrylic prepolymer having two or more acryloyl groups in one molecule and crosslinking with ionizing radiation to form a three-dimensional network structure, an isocyanate prepolymer and a release agent, characterized in that Surface protective film. The surface protective film according to claim 1 or 2, wherein the isocyanate prepolymer is 1% by weight or more and 50% by weight or less of the total resin solid content constituting the surface protection film. The surface protective film according to claim 1, wherein the ionizing radiation curable resin composition comprises a photopolymerizable prepolymer having a releasability. The surface protective film according to claim 2 or 4, wherein the mold release agent or the photopolymerizable prepolymer having mold release property is a silicone compound. 6. The surface protective film according to claim 5, wherein the silicone compound is silicone acrylate. 7. The surface protective film according to claim 6, wherein the silicone acrylate has a silicon content of 50% by weight or more and 90% by weight or less, a number average molecular weight of 5000 to 20000, and a number of acrylate functional groups of 3 or more. The surface protective film according to any one of claims 1, 2, and 4, wherein a haze difference before and after the taper wear hardness test in JIS K5400: 1990 is less than 25. The surface protective material of any one of Claims 1, 2, and 4 on one side of a plastic film, and the adhesive layer on the other side.