JP7142482B2 - surface protection film - Google Patents

Description

The present invention relates to a surface protection film.

In the manufacturing process of optical members and electronic members, in order to prevent the surfaces of the optical members and electronic members from being damaged during processing, assembly, inspection, transportation, etc., the optical members and electronic members are generally treated with A surface protective film is attached to the exposed surface of the member. Such a surface protective film is peeled off from an optical member or an electronic member when surface protection is no longer necessary (Patent Document 1).

In the optical member or electronic member to which such a surface protective film is attached, when the surface protective film is to be peeled off as described above, the interface between the surface protective film and the optical member or the electronic member may be damaged. It is important that the film can be peeled off smoothly.

However, in the case where optical members and electronic members are equipped with fragile members such as thin glass and barrier films, when trying to peel off the pasted surface protective film, the conventional surface protective film with easy peelability will be removed. Even when used, the peel force may cause the fragile member to break.

For this reason, there has been reported a surface protective film with even lighter releasability, ie, ultra-light releasability, compared to conventional surface protective films with easy releasability (Patent Document 2).

However, the conventional technique has a problem that, for example, when stored in a harsh environment for a long period of time, the adhesive strength increases with time, resulting in heavy peeling.

In order to suppress heavy peeling, a method of adding an excessive amount of an additive as reported in Patent Document 2 is also available. However, when such a method is employed, the degree of contamination of the surface of the adherend after peeling of the surface protective film is large, and when the surface protective film is applied again, the contamination of the surface of the adherend causes the surface protective film to become detached. There is a problem that it becomes difficult to stick.

As described above, for example, in the manufacturing process of optical members and electronic members, especially in the surface protective film that is attached to the exposed surface to prevent the surface from being scratched during processing, assembly, inspection, transportation, etc. In addition, it is required to be able to sufficiently suppress heavy peeling over time even when stored for a long time in a severe environment, and to be able to sufficiently reduce the contamination of the surface of the adherend.

JP 2016-17109 A JP 2017-160422 A

The problem of the present invention is that it does not easily peel off from the adherend, can sufficiently suppress heavy peeling over time even when stored for a long time in a harsh environment, and can be attached to the adherend. An object of the present invention is to provide a surface protective film which has sufficiently low contamination on the surface of the adherend.

The surface protection film of the present invention is
A surface protection film having an adhesive layer,
After the pressure-sensitive adhesive layer of the surface protective film was attached to a glass plate and allowed to stand at a temperature of 23° C. for 30 minutes, the surface protective film was peeled off from the glass plate at a temperature of 23° C. at a peeling angle of 180 degrees and a peeling speed of 300 mm/min. The peel force A is 0.005 N/25 mm to 0.50 N/25 mm when the peel force when peeled is defined as peel force A,
After the pressure-sensitive adhesive layer of the surface protective film was attached to a glass plate and allowed to stand at a temperature of 100° C. for 2 days, the surface protective film was peeled off from the glass plate at a temperature of 23° C. at a peeling angle of 180 degrees and a peeling speed of 300 mm/min. When the peel force at the time of peeling is defined as peel force B, the peel force aging rate P calculated by (peeling force B/peeling force A) × 100 is 400% or less,
The pressure-sensitive adhesive layer has a storage modulus at −70° C. of 5.0×10 ⁸ Pa to 1.0×10 ¹⁰ Pa,
The pressure-sensitive adhesive layer has a storage modulus at 23° C. of 7.0×10 ⁵ Pa to 1.0×10 ⁷ Pa,
The pressure-sensitive adhesive layer has a storage modulus at 100° C. of 7.0×10 ⁵ Pa to 5.0×10 ⁶ Pa.

In one embodiment, after the adhesive layer of the surface protection film is attached to a glass plate and left at 23° C. for 7 days, the surface protection film is peeled off from the glass plate at a temperature of 23° C. at a peeling angle of 180 degrees. When the peel strength when peeled at a peel speed of 300 mm/min is defined as peel strength C, the rate of increase in peel strength over time calculated by (peeling strength C/peeling strength A)×100 is 160% or less.

In one embodiment, the surface protection film of the present invention has a residual adhesion rate to a glass plate of 50% or more at 23°C.

In one embodiment, the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive composition, and the pressure-sensitive adhesive composition contains a base polymer and a silicone-based additive and/or a fluorine-based additive. .

In one embodiment, the adhesive composition contains a fatty acid ester.

In one embodiment, the silicone additive is at least one compound selected from siloxane bond-containing compounds, hydroxyl group-containing silicone compounds, and crosslinkable functional group-containing silicone compounds.

In one embodiment, the fluorine-based additive is at least one selected from a fluorine-containing compound, a hydroxyl group-containing fluorine-based compound, and a crosslinkable functional group-containing fluorine-based compound.

In one embodiment, the base polymer is at least one selected from urethane prepolymers, polyols, acrylic resins, rubber resins, and silicone resins.

The optical member of the present invention has the surface protective film of the present invention adhered thereto.

The electronic member of the present invention has the surface protection film of the present invention adhered thereto.

According to the present invention, it is not easily peeled off from the adherend, and even if the initial peeling force after sticking to the adherend is large, heavy peeling over time can be sufficiently suppressed, and the adhesive can be adhered to the adherend. It is possible to provide a surface protective film that causes sufficiently low contamination of the surface of the adherend when applied.

1 is a schematic cross-sectional view of a surface protection film according to one embodiment of the present invention; FIG.

≪≪A. Surface protection film>>>>
The surface protective film of the present invention has an adhesive layer. As long as the surface protective film of the present invention has a pressure-sensitive adhesive layer, it may be provided with any appropriate other member within a range that does not impair the effects of the present invention. Typically, the surface protection film of the invention has a substrate layer and an adhesive layer.

FIG. 1 is a schematic cross-sectional view of a surface protection film according to one embodiment of the invention. In FIG. 1, the surface protection film 10 comprises a substrate layer 1 and an adhesive layer 2. As shown in FIG. In FIG. 1, the substrate layer 1 and the adhesive layer 2 are laminated directly.

In FIG. 1, the surface of the pressure-sensitive adhesive layer 2 opposite to the substrate layer 1 is provided with any appropriate release liner (also referred to as release sheet or separator) for protection before use. (not shown). The release liner includes, for example, a release liner in which the surface of a base material (liner base material) such as paper or plastic film is treated with silicone, or a base material (liner base material) such as paper or plastic film whose surface is coated with a polyolefin resin. Examples include laminated release liners. Examples of plastic films as liner substrates include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polybutylene terephthalate film, Polyurethane films, ethylene-vinyl acetate copolymer films and the like are included. A polyethylene film is preferable as the plastic film as the liner base material.

The thickness of the release liner is preferably 1 μm to 500 μm, more preferably 3 μm to 450 μm, even more preferably 5 μm to 400 μm, particularly preferably 10 μm to 300 μm.

The thickness of the surface protective film is preferably 5 μm to 500 μm, more preferably 10 μm to 450 μm, still more preferably 15 μm to 400 μm, and particularly preferably 20 μm to 300 μm.

The surface protective film of the present invention is prepared by bonding the pressure-sensitive adhesive layer of the surface protective film to a glass plate and leaving it at a temperature of 23° C. for 30 minutes, then peeling off the surface protective film from the glass plate at a temperature of 23° C. When peel force A is the peel force when peeled at a peel speed of 300 mm / min, peel force A is preferably 0.005 N / 25 mm to 0.50 N / 25 mm, more preferably 0.007 N / 25 mm ~ 0.40 N/25 mm, more preferably 0.010 N/25 mm to 0.30 N/25 mm, still more preferably 0.012 N/25 mm to 0.20 N/25 mm, still more preferably 0.015 N/ 25 mm to 0.10 N/25 mm, particularly preferably 0.017 N/25 mm to 0.075 N/25 mm, most preferably 0.020 N/25 mm to 0.050 N/25 mm. If the peeling force A is within the above range, the surface protection film of the present invention can be difficult to peel off easily from the adherend. The surface protective film of the present invention attached to the exposed surface of the electronic member may be less likely to come off. The details of the measurement of the peeling force A will be described later.

The surface protective film of the present invention is prepared by bonding the pressure-sensitive adhesive layer of the surface protective film to a glass plate and leaving it at a temperature of 100° C. for 2 days, then peeling the surface protective film from the glass plate at a temperature of 23° C. When the peel force when peeled at a peel speed of 300 mm / min is defined as peel force B, peel force B is preferably 0.010 N / 25 mm to 1.0 N / 25 mm, more preferably 0.015 N / 25 mm 0.75 N/25 mm, more preferably 0.020 N/25 mm to 0.50 N/25 mm, particularly preferably 0.025 N/25 mm to 0.25 N/25 mm, most preferably 0.030 N/ 25 mm to 0.20 N/25 mm. If the peel force B is within the above range, the surface protective film of the present invention can sufficiently suppress heavy peeling over time even when stored for a long period of time in a harsh environment. The details of the measurement of the peeling force B will be described later.

In the surface protective film of the present invention, the peel force aging rate P calculated by (peeling force B/peeling force A)×100 for peel force A and peel force B is preferably 400% or less, more preferably is 375% or less, more preferably 350% or less, particularly preferably 325% or less, and most preferably 300% or less. Regarding the lower limit of the peel force increase rate P over time, the smaller the better, but in reality, it is preferably 80% or more. If the rate of increase in peel strength over time P is within the above range, the surface protective film of the present invention will not be easily peeled off from the adherend, and even if stored for a long period of time in a harsh environment, it will not become heavy over time. Exfoliation can be sufficiently suppressed.

In the surface protective film of the present invention, the pressure-sensitive adhesive layer of the surface protective film is attached to a glass plate, left at 23°C for 7 days, and then the surface protective film is peeled from the glass plate at a peeling angle of 180 degrees at a temperature of 23°C. When peel force C is the peel force when peeled at a speed of 300 mm / min, peel force C is preferably 0.005 N / 25 mm to 0.50 N / 25 mm, more preferably 0.007 N / 25 mm to 0.40 N/25 mm, more preferably 0.010 N/25 mm to 0.30 N/25 mm, still more preferably 0.012 N/25 mm to 0.20 N/25 mm, still more preferably 0.015 N/25 mm ~0.10 N/25 mm, particularly preferably 0.017 N/25 mm to 0.075 N/25 mm, most preferably 0.020 N/25 mm to 0.060 N/25 mm. If the peel force C is within the above range, the surface protective film of the present invention can sufficiently suppress heavy peeling over time even when stored for a long period of time in a harsh environment. The details of the measurement of the peeling force C will be described later.

In the surface protective film of the present invention, the peel force aging rate Q calculated by (peeling force C/peeling force A)×100 for peel force A and peel force C is preferably 160% or less, and more preferably. is 155% or less, more preferably 150% or less, particularly preferably 145% or less, and most preferably 140% or less. Regarding the lower limit of the peel force aging rate Q, the smaller the better, but in reality, it is preferably 80% or more. If the rate of increase in peel force over time Q is within the above range, the surface protective film of the present invention will not be easily peeled off from the adherend, and even if stored for a long time in a harsh environment, it will remain stable over time. Heavy peeling can be suppressed more sufficiently.

In the surface protective film of the present invention, the storage elastic modulus of the pressure-sensitive adhesive layer at −70° C. is preferably 5.0×10 ⁸ Pa to 1.0×10 ¹⁰ Pa, more preferably 7.0×10 ⁸ Pa to 8.0×10 ⁹ Pa, more preferably 9.0×10 ⁸ Pa to 6.0×10 ⁹ Pa, particularly preferably 1.0×10 ⁹ Pa to 4.0×10 ⁹ Pa, most preferably 1.5×10 ⁹ Pa to 3.0×10 ⁹ Pa. If the storage modulus of the pressure-sensitive adhesive layer at −70° C. is within the above range, the surface protective film of the present invention will not be easily peeled off from the adherend, and the initial peeling after sticking to the adherend will not occur. Even if the force is large, heavy peeling over time can be sufficiently suppressed, and the effect of sufficiently low contamination of the surface of the adherend due to attachment to the adherend can be further exhibited. The details of the measurement of the storage modulus of the pressure-sensitive adhesive layer at -70°C will be described later.

In the surface protective film of the present invention, the storage elastic modulus of the adhesive layer at 23° C. is preferably 7.0×10 ⁵ Pa to 1.0×10 ⁷ Pa, more preferably 7.0×10 ⁵ . Pa to 8.0×10 ⁶ Pa, more preferably 7.0×10 ⁵ Pa to 6.0×10 ⁶ Pa, particularly preferably 7.0×10 ⁵ Pa to 4.0×10 ⁶ Pa, most preferably 7.0×10 ⁵ Pa to 2.0×10 ⁶ Pa. If the storage elastic modulus of the pressure-sensitive adhesive layer at 23° C. is within the above range, the surface protective film of the present invention will not be easily peeled off from the adherend, and the initial peel strength after sticking to the adherend will be It is possible to sufficiently suppress heavy peeling over time even if it is large, and it is possible to exhibit the effect of sufficiently low contamination of the surface of the adherend by sticking to the adherend. The details of the measurement of the storage elastic modulus of the pressure-sensitive adhesive layer at 23°C will be described later.

In the surface protective film of the present invention, the storage elastic modulus of the adhesive layer at 100° C. is preferably 7.0×10 ⁵ Pa to 5.0×10 ⁶ Pa, more preferably 7.0×10 ⁵ . Pa to 3.0×10 ⁶ Pa, more preferably 7.0×10 ⁵ Pa to 2.0×10 ⁶ Pa, particularly preferably 7.0×10 ⁵ Pa to 1.0×10 ⁶ Pa Pa, most preferably 7.0×10 ⁵ Pa to 9.9×10 ⁵ Pa. If the storage elastic modulus at 100°C of the pressure-sensitive adhesive layer is within the above range, the surface protective film of the present invention will not be easily peeled off from the adherend, and the initial peel strength after sticking to the adherend will be It is possible to sufficiently suppress heavy peeling over time even if it is large, and it is possible to exhibit the effect of sufficiently low contamination of the surface of the adherend by sticking to the adherend. The details of the measurement of the storage elastic modulus of the pressure-sensitive adhesive layer at 100°C will be described later.

The surface protective film of the present invention preferably has a residual adhesion rate of 50% or more, more preferably 60% to 100%, still more preferably 70% to 100%, and particularly preferably 80% to 100%. %, most preferably between 85% and 100%. If the residual adhesion rate is within the above range, the surface protective film of the present invention can exhibit the effect of sufficiently reducing the contamination of the surface of an adherend when it is attached to the adherend. The details of the measurement of the residual adhesion rate will be described later.

The surface protection film of the invention can be produced by any appropriate method. As such a manufacturing method, for example,
(1) A method of applying a solution or hot melt of a material for forming an adhesive layer onto a substrate layer,
(2) A method of transferring a pressure-sensitive adhesive layer formed by applying a solution or hot melt of a material for forming the pressure-sensitive adhesive layer onto a separator onto a substrate layer,
(3) A method of extruding and coating the material for forming the pressure-sensitive adhesive layer onto the substrate layer,
(4) A method of extruding a substrate layer and an adhesive layer in two layers or multiple layers,
(5) A method of laminating a single adhesive layer on a substrate layer or a method of laminating two adhesive layers together with a laminate layer,
(6) A method of two-layer or multi-layer lamination of an adhesive layer and a substrate layer-forming material such as a film or laminate layer,
It can be performed according to any appropriate manufacturing method such as.

Examples of coating methods that can be used include a roll coater method, a comma coater method, a die coater method, a reverse coater method, a silk screen method, and a gravure coater method.

«A-1. Base layer≫
The base material layer may consist of only one layer, or may consist of two or more layers. The substrate layer may be stretched.

The thickness of the substrate layer is preferably 4 μm to 450 μm, more preferably 8 μm to 400 μm, even more preferably 12 μm to 350 μm, and particularly preferably 16 μm to 250 μm.

For the surface of the base layer on which the pressure-sensitive adhesive layer is not attached, for the purpose of forming a roll that can be easily unwound, for example, fatty acid amide, polyethyleneimine, long-chain alkyl additives are added to the base layer. etc. can be added for release treatment, or a coat layer made of any suitable release agent such as a silicone-based, long-chain alkyl-based, or fluorine-based release agent can be provided.

Any appropriate material can be adopted as the material of the base material layer depending on the application. Examples include plastics, paper, metal films, and non-woven fabrics. Preferably, it is plastic. That is, the substrate layer is preferably a plastic film. The base material layer may be composed of one kind of material, or may be composed of two or more kinds of materials. For example, it may be composed of two or more types of plastics.

Examples of the plastics include polyester-based resins, polyamide-based resins, and polyolefin-based resins. Polyester-based resins include, for example, polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate. Examples of polyolefin-based resins include homopolymers of olefin monomers and copolymers of olefin monomers. Specific examples of polyolefin-based resins include, for example, homopolypropylene; block-, random-, and graft-based propylene-based copolymers having an ethylene component as a copolymerization component; reactor TPO; low-density, high-density, linear Ethylene-based polymers with low density, ultra-low density, etc.; ethylene/propylene copolymer, ethylene/vinyl acetate copolymer, ethylene/methyl acrylate copolymer, ethylene/ethyl acrylate copolymer, ethylene/acrylic acid ethylene-based copolymers such as butyl copolymers, ethylene/methacrylic acid copolymers, and ethylene/methyl methacrylate copolymers;

The base material layer may contain any appropriate additive as needed. Examples of additives that can be contained in the base material layer include antioxidants, ultraviolet absorbers, light stabilizers, antistatic agents, fillers, pigments, and the like. The type, number, and amount of additives that can be contained in the base material layer can be appropriately set according to the purpose. In particular, when the material of the substrate layer is plastic, it is preferable to contain some of the above additives for the purpose of preventing deterioration. From the viewpoint of improving weather resistance, particularly preferred additives include antioxidants, ultraviolet absorbers, light stabilizers, and fillers.

Any appropriate antioxidant can be employed as the antioxidant. Examples of such antioxidants include phenol-based antioxidants, phosphorus-based processing heat stabilizers, lactone-based processing heat stabilizers, sulfur-based heat-resistant stabilizers, and phenol/phosphorus-based antioxidants. The content of the antioxidant is preferably 1% by weight or less, more preferably 1% by weight or less, relative to the base resin of the base layer (when the base layer is a blend, the blend is the base resin). It is 0.5 wt % or less, more preferably 0.01 wt % to 0.2 wt %.

Any appropriate UV absorber can be adopted as the UV absorber. Examples of such ultraviolet absorbers include benzotriazole-based ultraviolet absorbers, triazine-based ultraviolet absorbers, and benzophenone-based ultraviolet absorbers. The content of the ultraviolet absorber is preferably 2% by weight or less with respect to the base resin forming the base layer (when the base layer is a blend, the blend is the base resin), and more It is preferably 1 wt % or less, more preferably 0.01 wt % to 0.5 wt %.

Any suitable light stabilizer can be employed as the light stabilizer. Examples of such light stabilizers include hindered amine light stabilizers and benzoate light stabilizers. The content of the light stabilizer is preferably 2% by weight or less with respect to the base resin forming the base layer (when the base layer is a blend, the blend is the base resin), and more It is preferably 1 wt % or less, more preferably 0.01 wt % to 0.5 wt %.

Any appropriate filler can be adopted as the filler. Examples of such fillers include inorganic fillers. Specific examples of inorganic fillers include carbon black, titanium oxide, and zinc oxide. The content of the filler is preferably 20% by weight or less, more preferably 20% by weight or less, relative to the base resin forming the base layer (when the base layer is a blend, the blend is the base resin). is 10% by weight or less, more preferably 0.01% to 10% by weight.

Further, the additive preferably includes inorganic, low-molecular-weight, and high-molecular-weight antistatic agents such as surfactants, inorganic salts, polyhydric alcohols, metal compounds, and carbon for the purpose of imparting antistatic properties. In particular, high-molecular-weight antistatic agents and carbon are preferred from the viewpoint of contamination and maintenance of adhesiveness.

«A-2. Adhesive layer≫
The adhesive layer may be composed of an adhesive. The adhesive can be formed from the adhesive composition.

The pressure-sensitive adhesive layer can be formed by any appropriate method. Examples of such a method include a method of applying an adhesive composition onto a substrate layer to form an adhesive layer on the substrate layer. Examples of such coating methods include roll coating, gravure coating, reverse coating, roll brushing, spray coating, air knife coating, and extrusion coating using a die coater.

The thickness of the adhesive layer is preferably 1 μm to 150 μm, more preferably 2 μm to 140 μm, still more preferably 3 μm to 130 μm, still more preferably 4 μm to 120 μm, still more preferably 5 μm to 100 μm. , more preferably 10 μm to 90 μm, particularly preferably 20 μm to 85 μm, most preferably 30 μm to 80 μm.

The adhesive composition preferably contains a base polymer, a low molecular weight polyol, and a silicone additive and/or a fluorine additive. Since the pressure-sensitive adhesive composition contains a base polymer, a low-molecular-weight polyol, and a silicone-based additive and/or a fluorine-based additive, the surface protective film of the present invention is not easily peeled off from the adherend. It is said that even if the initial peel force after sticking to the adherend is large, heavy peeling over time can be sufficiently suppressed, and the contamination of the adherend surface due to sticking to the adherend is sufficiently low. The effect can be expressed more. In a preferred embodiment of the present invention, particularly by adopting an unconventional technical idea of using a low-molecular-weight polyol in combination with a silicone-based additive and/or a fluorine-based additive, the adhesive can be easily peeled off from the adherend. Even if the initial peel force after sticking to the adherend is large, heavy peeling over time can be sufficiently suppressed, and the surface of the adherend is sufficiently stained by sticking to the adherend. It is possible to provide a surface protective film that can exhibit the effect of lowering the

The total content of the base polymer, low-molecular-weight polyol, silicone-based additive and fluorine-based additive in the pressure-sensitive adhesive composition is preferably 50% by weight to 100% by weight, more preferably 60% by weight. 100% by weight, more preferably 70% to 100% by weight, particularly preferably 75% to 100% by weight, and most preferably 80% to 100% by weight. If the content of the total amount of the base polymer, the silicone additive, and the fluorine additive in the pressure-sensitive adhesive composition is within the above range, the surface protection film of the present invention can be easily peeled off from the adherend. Even if the initial peel force after sticking to the adherend is large, heavy peeling over time can be sufficiently suppressed, and the contamination of the adherend surface due to sticking to the adherend is sufficiently The effect of being low can be expressed more.

The content of the low-molecular-weight polyol in the pressure-sensitive adhesive composition is preferably 0.01 to 50 parts by weight, more preferably 0.05 to 25 parts by weight, relative to 100 parts by weight of the base polymer. , more preferably 0.07 to 30 parts by weight, more preferably 0.1 to 20 parts by weight, still more preferably 0.3 to 15 parts by weight, particularly preferably 0.5 to 10 parts by weight, most preferably 0.7 to 7.0 parts by weight. If the content of the low-molecular-weight polyol in the pressure-sensitive adhesive composition is within the above range, the surface protective film of the present invention will not be easily peeled off from the adherend, and the initial Even if the peeling force is large, heavy peeling over time can be sufficiently suppressed, and the effect of sufficiently low contamination of the surface of the adherend due to attachment to the adherend can be further exhibited.

The content of the silicone-based additive and/or the fluorine-based additive in the pressure-sensitive adhesive composition is preferably 0.001 part by weight as the total amount of the silicone-based additive and the fluorine-based additive with respect to 100 parts by weight of the base polymer. 50 parts by weight, more preferably 0.005 parts by weight to 25 parts by weight, still more preferably 0.01 parts by weight to 10 parts by weight, still more preferably 0.01 parts by weight to 1 part by weight more preferably 0.01 to 0.50 parts by weight, particularly preferably 0.01 to 0.30 parts by weight, most preferably 0.01 to 0.10 parts by weight is. If the content of the silicone-based additive and/or the fluorine-based additive in the pressure-sensitive adhesive composition is within the above range, the surface protective film of the present invention will not be easily peeled off from the adherend, Even if the initial peel force after sticking to the surface is large, it is possible to sufficiently suppress heavy peeling over time, and the effect that the contamination of the surface of the adherend due to sticking to the adherend is sufficiently low. can.

That is, when the pressure-sensitive adhesive composition contains a silicone-based additive but does not contain a fluorine-based additive, the content of the silicone-based additive with respect to 100 parts by weight of the base polymer is preferably 0.001 to 50 parts by weight. parts, more preferably 0.005 to 25 parts by weight, still more preferably 0.01 to 10 parts by weight, still more preferably 0.01 to 1 part by weight, and further It is preferably 0.01 to 0.50 parts by weight, particularly preferably 0.01 to 0.30 parts by weight, most preferably 0.01 to 0.10 parts by weight. If the content of the silicone-based additive in the pressure-sensitive adhesive composition is within the above range, the surface protective film of the present invention will not be easily peeled off from the adherend, and the initial Even if the peeling force of is large, heavy peeling over time can be sufficiently suppressed, and the effect of sufficiently low contamination of the adherend surface due to attachment to the adherend can be further exhibited.

Further, when the pressure-sensitive adhesive composition does not contain a silicone-based additive but contains a fluorine-based additive, the content of the fluorine-based additive with respect to 100 parts by weight of the base polymer is preferably 0.001 to 50 parts by weight. parts, more preferably 0.005 to 25 parts by weight, still more preferably 0.01 to 10 parts by weight, still more preferably 0.01 to 1 part by weight, and further It is preferably 0.01 to 0.50 parts by weight, particularly preferably 0.01 to 0.30 parts by weight, most preferably 0.01 to 0.10 parts by weight. If the content of the fluorine-based additive in the pressure-sensitive adhesive composition is within the above range, the surface protective film of the present invention will not be easily peeled off from the adherend, and the initial Even if the peeling force of is large, heavy peeling over time can be sufficiently suppressed, and the effect of sufficiently low contamination of the adherend surface due to attachment to the adherend can be further exhibited.

When both the silicone-based additive and the fluorine-based additive are contained in the pressure-sensitive adhesive composition, the total content of the silicone-based additive and the fluorine-based additive with respect to 100 parts by weight of the base polymer is preferably 0.5. 001 parts by weight to 50 parts by weight, more preferably 0.005 parts by weight to 25 parts by weight, still more preferably 0.01 parts by weight to 10 parts by weight, still more preferably 0.01 parts by weight to 1 part by weight parts by weight, more preferably 0.01 to 0.50 parts by weight, particularly preferably 0.01 to 0.30 parts by weight, and most preferably 0.01 to 0.5 parts by weight. 10 parts by weight. If the total content of the silicone-based additive and the fluorine-based additive in the pressure-sensitive adhesive composition is within the above range, the surface protective film of the present invention will not be easily peeled off from the adherend, Even if the initial peel force after sticking to the surface is large, it is possible to sufficiently suppress heavy peeling over time, and the effect that the contamination of the surface of the adherend due to sticking to the adherend is sufficiently low. can.

<A-2-1. Base polymer>
The base polymer is preferably at least one selected from urethane prepolymers, polyols, acrylic resins, rubber resins, and silicone resins. When the base polymer is at least one selected from urethane prepolymers, polyols, acrylic resins, rubber resins, and silicone resins, the surface protective film of the present invention is not easily peeled off from the adherend. Even if the initial peel force after sticking to the adherend is large, heavy peeling over time can be sufficiently suppressed, and the contamination of the adherend surface due to sticking to the adherend is sufficiently low. can be expressed more.

[A-2-1-a. Urethane prepolymer]
The urethane prepolymer is preferably a polyurethane polyol, more preferably polyester polyol (a1) or polyether polyol (a2), each alone or in a mixture of (a1) and (a2) in the presence of a catalyst. It is obtained by reacting with an organic polyisocyanate compound (a3) under or without a catalyst.

Any appropriate polyester polyol can be used as the polyester polyol (a1). Examples of such polyester polyols (a1) include polyester polyols obtained by reacting an acid component and a glycol component. Examples of acid components include terephthalic acid, adipic acid, azelaic acid, sebacic acid, phthalic anhydride, isophthalic acid, and trimellitic acid. Examples of glycol components include ethylene glycol, propylene glycol, diethylene glycol, butylene glycol, 1,6-hexane glycol, 3-methyl-1,5-pentanediol, 3,3′-dimethylolheptane, polyoxyethylene glycol, Examples include polyoxypropylene glycol, 1,4-butanediol, neopentyl glycol, butylethylpentanediol, and polyol components such as glycerin, trimethylolpropane, and pentaerythritol. Polyester polyols (a1) also include polyester polyols obtained by ring-opening polymerization of lactones such as polycaprolactone, poly(β-methyl-γ-valerolactone) and polyvalerolactone.

As the molecular weight of the polyester polyol (a1), it is possible to use from low molecular weight to high molecular weight. As for the molecular weight of the polyester polyol (a1), the number average molecular weight is preferably 100 to 100,000. If the number average molecular weight is less than 100, the reactivity becomes high and gelation may easily occur. If the number average molecular weight exceeds 100,000, the reactivity may become low, and furthermore, the cohesive strength of the polyurethane polyol itself may become small. The amount of the polyester polyol (a1) used is preferably 0 mol % to 90 mol % of the polyol constituting the polyurethane polyol.

Any appropriate polyether polyol can be used as the polyether polyol (a2). Examples of such polyether polyols (a2) include water, propylene glycol, ethylene glycol, glycerin, trimethylolpropane, and other low-molecular-weight polyols as initiators, and ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, and the like. Examples include polyether polyols obtained by polymerizing oxirane compounds. Specific examples of such polyether polyols (a2) include polyether polyols having two or more functional groups, such as polypropylene glycol, polyethylene glycol, and polytetramethylene glycol.

As the molecular weight of the polyether polyol (a2), it is possible to use from low molecular weight to high molecular weight. As for the molecular weight of the polyether polyol (a2), the number average molecular weight is preferably 100 to 100,000. If the number average molecular weight is less than 100, the reactivity becomes high and gelation may easily occur. If the number average molecular weight exceeds 100,000, the reactivity may become low, and furthermore, the cohesive strength of the polyurethane polyol itself may become small. The amount of the polyether polyol (a2) used is preferably 0 mol % to 90 mol % of the polyol constituting the polyurethane polyol.

Part of the polyether polyol (a2), if necessary, glycols such as ethylene glycol, 1,4-butanediol, neopentyl glycol, butylethylpentanediol, glycerin, trimethylolpropane, pentaerythritol, It can be used in combination with polyvalent amines such as ethylenediamine, N-aminoethylethanolamine, isophoronediamine, xylylenediamine, and the like.

As the polyether polyol (a2), only a bifunctional polyether polyol may be used, or a polyether having a number average molecular weight of 100 to 100,000 and at least 3 or more hydroxyl groups in one molecule. Part or all of the polyol may be used. As the polyether polyol (a2), a polyether polyol having a number average molecular weight of 100 to 100,000 and having at least 3 or more hydroxyl groups in one molecule is used in whole or in part to improve adhesive strength and removability. Balance can be good. In such a polyether polyol, if the number average molecular weight is less than 100, the reactivity becomes high and there is a possibility that gelation is likely to occur. Moreover, in such a polyether polyol, if the number average molecular weight exceeds 100,000, the reactivity may be lowered, and the cohesive strength of the polyurethane polyol itself may be lowered. The number average molecular weight of such polyether polyols is more preferably 100-10,000.

Any appropriate organic polyisocyanate compound can be used as the organic polyisocyanate compound (a3). Examples of such organic polyisocyanate compounds (a3) include aromatic polyisocyanates, aliphatic polyisocyanates, araliphatic polyisocyanates, and alicyclic polyisocyanates.

Examples of aromatic polyisocyanates include 1,3-phenylene diisocyanate, 4,4'-diphenyldiisocyanate, 1,4-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6 - tolylene diisocyanate, 4,4'-toluidine diisocyanate, 2,4,6-triisocyanatotoluene, 1,3,5-triisocyanatobenzene, dianisidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4', 4″-triphenylmethane triisocyanate and the like.

Examples of aliphatic polyisocyanates include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate and the like.

Examples of araliphatic polyisocyanates include ω,ω'-diisocyanate-1,3-dimethylbenzene, ω,ω'-diisocyanate-1,4-dimethylbenzene, ω,ω'-diisocyanate-1,4-diethylbenzene , 1,4-tetramethylxylylene diisocyanate, 1,3-tetramethylxylylene diisocyanate, and the like.

Examples of alicyclic polyisocyanates include 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate, 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, methyl-2 ,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4,4′-methylenebis(cyclohexyl isocyanate), 1,4-bis(isocyanatomethyl)cyclohexane, 1,4-bis(isocyanatomethyl)cyclohexane and the like. be done.

As the organic polyisocyanate compound (a3), a trimethylolpropane adduct, a water-reacted biuret compound, a trimer having an isocyanurate ring, and the like can be used in combination.

Any appropriate catalyst can be used as the catalyst that can be used when obtaining the polyurethane polyol. Examples of such catalysts include tertiary amine compounds and organometallic compounds.

Tertiary amine compounds include, for example, triethylamine, triethylenediamine, 1,8-diazabicyclo(5,4,0)-undecene-7 (DBU) and the like.

Examples of organometallic compounds include tin-based compounds and non-tin-based compounds.

Examples of tin compounds include dibutyltin dichloride, dibutyltin oxide, dibutyltin dibromide, dibutyltin dimaleate, dibutyltin dilaurate (DBTDL), dibutyltin diacetate, dibutyltin sulfide, tributyltin sulfide, tributyltin oxide, tributyltin Tin acetate, triethyltin ethoxide, tributyltin ethoxide, dioctyltin oxide, tributyltin chloride, tributyltin trichloroacetate, tin 2-ethylhexanoate and the like.

Examples of non-tin compounds include titanium compounds such as dibutyl titanium dichloride, tetrabutyl titanate, and butoxy titanium trichloride; lead compounds such as lead oleate, lead 2-ethylhexanoate, lead benzoate, and lead naphthenate. iron-based compounds such as iron 2-ethylhexanoate and iron acetylacetonate; cobalt-based compounds such as cobalt benzoate and cobalt 2-ethylhexanoate; zinc-based compounds such as zinc naphthenate and zinc 2-ethylhexanoate; zirconium-based compounds such as zirconium naphthenate;

When a catalyst is used to obtain a polyurethane polyol, in a system in which two kinds of polyols, a polyester polyol and a polyether polyol, are present, gelation or a reaction solution may occur in a single catalyst system due to the difference in reactivity. The problem of turbidity is likely to occur. Therefore, by using two kinds of catalysts when obtaining a polyurethane polyol, the reaction rate, the selectivity of the catalyst, etc. can be easily controlled, and these problems can be solved. Combinations of such two types of catalysts include, for example, tertiary amine/organometallic, tin/non-tin, and tin/tin, preferably tin/tin, and more preferably. is a combination of dibutyltin dilaurate and tin 2-ethylhexanoate. The weight ratio of tin 2-ethylhexanoate/dibutyltin dilaurate is preferably less than 1, more preferably 0.2 to 0.6. If the compounding ratio is 1 or more, gelation may tend to occur due to the balance of catalytic activity.

When a catalyst is used in obtaining the polyurethane polyol, the amount of the catalyst used is preferably 0.01 with respect to the total amount of the polyester polyol (a1), the polyether polyol (a2) and the organic polyisocyanate compound (a3). % to 1.0% by weight.

If a catalyst is used in obtaining the polyurethane polyol, the reaction temperature is preferably below 100°C, more preferably between 85°C and 95°C. If the temperature is 100° C. or higher, it may become difficult to control the reaction rate and the crosslinked structure, and it may become difficult to obtain a polyurethane polyol having a predetermined molecular weight.

When obtaining a polyurethane polyol, it is not necessary to use a catalyst. In that case, the reaction temperature is preferably 100° C. or higher, more preferably 110° C. or higher. Moreover, when obtaining a polyurethane polyol under no catalyst, it is preferable to carry out reaction for 3 hours or more.

Methods for obtaining polyurethane polyol include, for example, 1) a method of charging a polyester polyol, a polyether polyol, a catalyst, and an organic polyisocyanate into a volumetric flask, and 2) a method of charging a polyester polyol, a polyether polyol, and a catalyst into a flask to produce an organic polyisocyanate. can be added dropwise. As a method for obtaining a polyurethane polyol, the method 2) is preferable from the viewpoint of controlling the reaction.

Any suitable solvent may be used in obtaining the polyurethane polyol. Examples of such solvents include methyl ethyl ketone, ethyl acetate, toluene, xylene and acetone. Among these solvents, toluene is preferred.

[A-2-1-b. Polyol]

Polyols preferably include, for example, polyester polyols, polyether polyols, polycaprolactone polyols, polycarbonate polyols, and castor oil-based polyols. The polyol is more preferably polyether polyol.

A polyester polyol can be obtained, for example, by an esterification reaction between a polyol component and an acid component.

Polyol components include, for example, ethylene glycol, diethylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2-butyl-2-ethyl-1 ,3-propanediol, 2,4-diethyl-1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 2-methyl -1,8-octanediol, 1,8-decanediol, octadecanediol, glycerin, trimethylolpropane, pentaerythritol, hexanetriol, polypropylene glycol and the like. Examples of acid components include succinic acid, methylsuccinic acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, 1,12-dodecanedioic acid, 1,14-tetradecanedioic acid, dimer acid, 2-methyl-1, 4-cyclohexanedicarboxylic acid, 2-ethyl-1,4-cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, isophthalic acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid, 4,4'-biphenyldicarboxylic acid , acid anhydrides thereof, and the like.

Examples of polyether polyols include water, low-molecular-weight polyols (propylene glycol, ethylene glycol, glycerin, trimethylolpropane, pentaerythritol, etc.), bisphenols (bisphenol A, etc.), dihydroxybenzenes (catechol, resorcinol, hydroquinone, etc.). is used as an initiator, polyether polyols obtained by addition polymerization of alkylene oxides such as ethylene oxide, propylene oxide and butylene oxide. Specific examples include polyethylene glycol, polypropylene glycol, polytetramethylene glycol and the like.

Examples of polycaprolactone polyols include caprolactone-based polyester diols obtained by ring-opening polymerization of cyclic ester monomers such as ε-caprolactone and σ-valerolactone.

Polycarbonate polyols include, for example, polycarbonate polyols obtained by subjecting the above polyol component and phosgene to a polycondensation reaction; Polycarbonate polyols obtained by transesterification condensation with carbonic acid diesters such as propylene carbonate, diphenyl carbonate, and dibenzyl carbonate; Copolycarbonate polyols obtained by using two or more of the above polyol components in combination; Various polycarbonate polyols above and carboxyl group-containing polyols Polycarbonate polyol obtained by esterifying a compound; Polycarbonate polyol obtained by etherifying the above various polycarbonate polyols and a hydroxyl group-containing compound; Obtained by transesterifying the above various polycarbonate polyols and an ester compound. Polycarbonate polyols; Polycarbonate polyols obtained by transesterification of various polycarbonate polyols and hydroxyl group-containing compounds; Polyester-based polycarbonate polyols obtained by polycondensation reaction of various polycarbonate polyols and dicarboxylic acid compounds; Various polycarbonate polyols and a copolymerized polyether-based polycarbonate polyol obtained by copolymerizing alkylene oxide; and the like.

Examples of castor oil-based polyols include castor oil-based polyols obtained by reacting castor oil fatty acids with the above polyol components. Specific examples include castor oil-based polyols obtained by reacting castor oil fatty acids with polypropylene glycol.

The number average molecular weight Mn of the polyol is preferably 300-100,000, more preferably 400-75,000, still more preferably 450-50,000, and particularly preferably 500-30,000. If the number average molecular weight Mn of the polyol is within the above range, the surface protective film of the present invention will not be easily peeled off from the adherend, and even if the initial peeling force after sticking to the adherend is large. It can sufficiently suppress heavy peeling over time, and can exhibit the effect of sufficiently low contamination of the surface of an adherend when attached to the adherend.

The polyol preferably contains a polyol (A1) having three OH groups and a number average molecular weight Mn of 300 to 100,000. Only one kind of polyol (A1) may be used, or two or more kinds thereof may be used.

The content of the polyol (A1) in the polyol is preferably 5% by weight or more, more preferably 25% to 100% by weight, still more preferably 50% to 100% by weight. If the content of the polyol (A1) in the polyol is within the above range, the surface protective film of the present invention will not be easily peeled off from the adherend, and the initial peel strength after sticking to the adherend will be It is possible to sufficiently suppress heavy peeling over time even if it is large, and it is possible to exhibit the effect of sufficiently low contamination of the surface of the adherend by sticking to the adherend.

The number average molecular weight Mn of the polyol (A1) is preferably from 1,000 to 100,000, more preferably from 1,000 to 80,000, even more preferably from 1,100 to 70,000, still more preferably from 1,200 to 60,000, and It is preferably 1,300 to 50,000, more preferably 1,400 to 40,000, still more preferably 1,500 to 35,000, particularly preferably 1,700 to 32,000, most preferably 2,000 to 30,000. If the number average molecular weight Mn of the polyol (A1) is within the above range, the surface protective film of the present invention will not be easily peeled off from the adherend, and the initial peeling force after sticking to the adherend will be Even if it is large, it can sufficiently suppress heavy peeling over time, and the effect of sufficiently low contamination of the surface of an adherend when attached to the adherend can be further exhibited.

The polyol may contain a polyol (A2) having 3 or more OH groups and a number average molecular weight Mn of 20000 or less. Only one kind of polyol (A2) may be used, or two or more kinds thereof may be used. The number average molecular weight Mn of the polyol (A2) is preferably 100 to 20000, more preferably 150 to 10000, even more preferably 200 to 7500, particularly preferably 300 to 6000, most preferably 300. ~5000. If the number average molecular weight Mn of the polyol (A2) is out of the above range, the peel strength of the surface protective film of the present invention may increase over time. The polyol (A2) is preferably a polyol having 3 OH groups (triol), a polyol having 4 OH groups (tetraol), a polyol having 5 OH groups (pentaol), or 6 OH groups. polyols (hexaols) having

The total amount of a polyol (tetraol) having 4 OH groups, a polyol having 5 OH groups (pentaol), and a polyol having 6 OH groups (hexaol) as the polyol (A2) is The content is preferably 70% by weight or less, more preferably 60% by weight or less, still more preferably 40% by weight or less, and particularly preferably 30% by weight or less. In the polyol, the total amount of a polyol (tetraol) having 4 OH groups, a polyol having 5 OH groups (pentaol), and a polyol having 6 OH groups (hexaol) as the polyol (A2) If the content in the polyol is within the above range, a pressure-sensitive adhesive layer with excellent transparency can be provided, and the surface protective film of the present invention does not easily peel off from the adherend and adheres to the adherend. Even if the initial peel force after application is large, heavy release over time can be sufficiently suppressed, and the effect of sufficiently low contamination of the surface of the adherend due to application to the adherend is further exhibited. obtain.

The content of polyol (A2) in the polyol is preferably 95% by weight or less, more preferably 0% to 75% by weight. If the content of the polyol (A2) in the polyol is within the above range, the surface protective film of the present invention will not be easily peeled off from the adherend, and the initial peel strength after being attached to the adherend will be It is possible to sufficiently suppress heavy peeling over time even if it is large, and it is possible to exhibit the effect of sufficiently low contamination of the surface of the adherend by sticking to the adherend.

As the polyol (A2), the content of the polyol having 4 or more OH groups and a number average molecular weight Mn of 20000 or less is preferably less than 70% by weight, more preferably 60% by weight or less, based on the total polyol. , more preferably 50% by weight or less, particularly preferably 40% by weight or less, and most preferably 30% by weight or less. As the polyol (A2), if the content of the polyol having 4 or more OH groups and a number average molecular weight Mn of 20000 or less relative to the total polyol is within the above range, a pressure-sensitive adhesive layer with excellent transparency can be provided. In addition, the surface protective film of the present invention is not easily peeled off from the adherend, and can sufficiently suppress heavy peeling over time even if the initial peeling force after sticking to the adherend is large. , the effect that the contamination of the surface of the adherend due to sticking to the adherend is sufficiently low can be further exhibited.

[A-2-1-c. Acrylic resin]
As the acrylic resin, any suitable acrylic pressure-sensitive adhesive such as known acrylic pressure-sensitive adhesives described in Japanese Patent Application Laid-Open No. 2013-241606 can be employed as long as the effects of the present invention are not impaired.

The acrylic resin may contain any appropriate component as long as the effects of the present invention are not impaired. Examples of such components include resin components other than acrylic resins, tackifiers, inorganic fillers, organic fillers, metal powders, pigments, foils, softeners, anti-aging agents, conductive agents, and UV absorbers. agents, antioxidants, light stabilizers, surface lubricants, leveling agents, corrosion inhibitors, heat stabilizers, polymerization inhibitors, lubricants, solvents, catalysts and the like.

[A-2-1-d. Rubber resin]
As the rubber-based resin, any suitable rubber-based pressure-sensitive adhesive such as known rubber-based pressure-sensitive adhesives described in JP-A-2015-074771 can be employed as long as the effects of the present invention are not impaired. These may be of only one type, or may be of two or more types.

The rubber-based resin may contain any appropriate component within a range that does not impair the effects of the present invention. Such components include, for example, resin components other than rubber-based resins, tackifiers, inorganic fillers, organic fillers, metal powders, pigments, foils, softeners, anti-aging agents, conductive agents, and ultraviolet absorbers. agents, antioxidants, light stabilizers, surface lubricants, leveling agents, corrosion inhibitors, heat stabilizers, polymerization inhibitors, lubricants, solvents, catalysts and the like.

[A-2-1-e. Silicone resin]
As the silicone-based pressure-sensitive adhesive, any suitable silicone-based pressure-sensitive adhesive such as known silicone-based pressure-sensitive adhesives described in JP-A-2014-047280 can be employed as long as the effects of the present invention are not impaired. . These may be of only one type, or may be of two or more types.

The silicone-based resin may contain any appropriate component as long as the effects of the present invention are not impaired. Such components include, for example, resin components other than silicone-based resins, tackifiers, inorganic fillers, organic fillers, metal powders, pigments, foils, softeners, anti-aging agents, conductive agents, and ultraviolet absorbers. agents, antioxidants, light stabilizers, surface lubricants, leveling agents, corrosion inhibitors, heat stabilizers, polymerization inhibitors, lubricants, solvents, catalysts and the like.

<A-2-2. Low molecular weight polyol>
Only one type of low-molecular-weight polyol may be used, or two or more types may be used.

Any appropriate low-molecular-weight polyol can be adopted as the low-molecular-weight polyol as long as the effects of the present invention are not impaired. Such low-molecular-weight polyols preferably include polyols having a number-average molecular weight Mn of 1,500 or less.

The number average molecular weight Mn of the low molecular weight polyol is preferably 1400 or less, more preferably 1300 or less, even more preferably 1200 or less, particularly preferably 1100 or less, most preferably 1000 or less. The lower limit of the number average molecular weight Mn of the low-molecular-weight polyol is preferably 50 or more, more preferably 100 or more, still more preferably 150 or more, particularly preferably 200 or more, and most preferably 250 or more. be. If the number average molecular weight Mn of the low-molecular-weight polyol is within the above range, the surface protective film of the present invention will not be easily peeled off from the adherend, and the initial peeling force after being attached to the adherend will be large. However, it is possible to sufficiently suppress heavy peeling over time, and the effect of sufficiently low contamination of the surface of the adherend due to attachment to the adherend can be further exhibited.

Examples of low-molecular-weight polyols preferably include polyester polyols, polyether polyols, polycaprolactone polyols, polycarbonate polyols, and castor oil-based polyols. Polyether polyols are more preferred as low-molecular-weight polyols.

Examples of polyether polyols include water, low-molecular-weight polyols (propylene glycol, ethylene glycol, glycerin, trimethylolpropane, pentaerythritol, etc.), bisphenols (bisphenol A, etc.), dihydroxybenzenes (catechol, resorcinol, hydroquinone, etc.). is used as an initiator, polyether polyols obtained by addition polymerization of alkylene oxides such as ethylene oxide, propylene oxide and butylene oxide. Specific examples include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyoxypropylene glyceryl ether, and the like.

The number of OH groups possessed by the low-molecular-weight polyol is preferably 2 to 6, more preferably 3 to 5, even more preferably 3 to 4, and particularly preferably 3. . If the number of OH groups possessed by the low-molecular-weight polyol is within the above range, the surface protective film of the present invention will not be easily peeled off from the adherend, and the initial peel strength after being attached to the adherend will be high. Even if it is large, it can sufficiently suppress heavy peeling over time, and the effect of sufficiently low contamination of the surface of an adherend when attached to the adherend can be further exhibited.

<A-2-3. Silicone additive>
Any appropriate silicone-based additive can be adopted as the silicone-based additive as long as it does not impair the effects of the present invention. Such a silicone-based additive is preferably at least one selected from a siloxane bond-containing compound, a hydroxyl group-containing silicone-based compound, and a crosslinkable functional group-containing silicone-based compound.

Only one type of silicone additive may be used, or two or more types may be used.

Examples of siloxane bond-containing compounds include polyether-modified polyorganosiloxanes in which polyether groups are introduced into the main chain or side chains of a polyorganosiloxane skeleton (polydimethylsiloxane, etc.), Polyester-modified polyorganosiloxane into which polyester groups are introduced, organic compound-introduced polyorganosiloxane into which an organic compound is introduced into the main chain or side chain of the polyorganosiloxane skeleton, silicone-modified polyorganosiloxane into (meth)acrylic resin into which polyorganosiloxane is introduced ( Examples include meth)acrylic resins, silicone-modified organic compounds obtained by introducing polyorganosiloxane into an organic compound, and silicone-containing organic compounds obtained by copolymerizing an organic compound and a silicone compound. As such a siloxane bond-containing polymer, commercially available products include, for example, the product name "LE-302" (manufactured by Kyoeisha Chemical Co., Ltd.), BYK series leveling agent manufactured by BYK Chemie Japan Co., Ltd. ("BYK-300 , BYK-301/302, BYK-306, BYK-307, BYK-310, BYK-315, BYK-313, BYK-320, BYK-322 ”, “BYK-323”, “BYK-325”, “BYK-330”, “BYK-331”, “BYK-333”, “BYK-337”, “BYK-341”, “BYK-344”, "BYK-345/346", "BYK-347", "BYK-348", "BYK-349", "BYK-370", "BYK-375", "BYK-377", "BYK-378", "BYK-UV3500", "BYK-UV3510", "BYK-UV3570", "BYK-3550", "BYK-SILCLEAN3700", "BYK-SILCLEAN3720", etc.), AC series leveling agents manufactured by Algin Chemie (" AC FS180", "AC FS360", "AC S20", etc.), Polyflow series leveling agents manufactured by Kyoeisha Chemical Co., Ltd. ("Polyflow KL-400X", "Polyflow KL-400HF", "Polyflow KL-401") , "Polyflow KL-402", "Polyflow KL-403", "Polyflow KL-404", etc.), KP series leveling agents manufactured by Shin-Etsu Chemical Co., Ltd. ("KP-323", "KP-326", "KP-341", "KP-104", "KP-110", "KP-112", etc.), Shin-Etsu Chemical Co., Ltd.'s X22 series, KF series, etc., leveling agents manufactured by Dow Corning Toray Co., Ltd. ( "LP-7001", "LP-7002", "8032ADDITIVE", "57ADDITIVE", "L-7604", "FZ-2110", "FZ-2105", "67ADDITIVE", "8618ADDITIVE", "3ADDITIVE", "56ADDITIVE" etc.).

Examples of hydroxyl group-containing silicone compounds include polyether-modified polyorganosiloxane in which a polyether group is introduced into the main chain or side chain of a polyorganosiloxane skeleton (polydimethylsiloxane, etc.), the main chain or side chain of the polyorganosiloxane skeleton. Polyester-modified polyorganosiloxane in which a polyester group is introduced into the base, organic compound-introduced polyorganosiloxane in which an organic compound is introduced into the main chain or side chain of the polyorganosiloxane skeleton, silicone-modified polyorganosiloxane in which polyorganosiloxane is introduced into (meth)acrylic resin Examples include (meth)acrylic resins, silicone-modified organic compounds obtained by introducing polyorganosiloxane into organic compounds, and silicone-containing organic compounds obtained by copolymerizing organic compounds and silicone compounds. In these, the hydroxyl group may be possessed by a polyorganosiloxane skeleton, or may be possessed by a polyether group, a polyester group, a (meth)acryloyl group, or an organic compound. Commercially available products of such hydroxyl-containing silicones include, for example, trade names "X-22-4015", "X-22-4039", "KF6000", "KF6001", "KF6002", "KF6003", "X-22-170BX", "X-22-170DX", "X-22-176DX", "X-22-176F" (manufactured by Shin-Etsu Chemical Co., Ltd.), BYK Chemie Japan Co., Ltd. -370”, “BYK-SILCLEAN3700”, and “BYK-SILCLEAN3720”.

Examples of crosslinkable functional group-containing silicone compounds include polyether-modified polyorganosiloxanes in which polyether groups are introduced into the main chain or side chains of a polyorganosiloxane skeleton (such as polydimethylsiloxane), and polyorganosiloxane skeleton main chains. Polyester-modified polyorganosiloxane in which polyester groups are introduced into the chain or side chain, organic compound-introduced polyorganosiloxane in which an organic compound is introduced into the main chain or side chain of the polyorganosiloxane skeleton, polyorganosiloxane added to (meth)acrylic resin Silicone-modified (meth)acrylic resins, silicone-modified organic compounds obtained by introducing polyorganosiloxane into organic compounds, silicone-containing organic compounds obtained by copolymerizing organic compounds and silicone compounds, and the like can be mentioned. In these, the crosslinkable functional group may be possessed by a polyorganosiloxane skeleton, or may be possessed by a polyether group, a polyester group, a (meth)acryloyl group, or an organic compound. Examples of crosslinkable functional groups include amino groups, epoxy groups, mercapto groups, carboxyl groups, isocyanate groups, and methacrylate groups. Examples of such isocyanate group-containing silicones include commercially available products such as "BY16-855", "SF8413", "BY16-839", "SF8421", and "BY16-750" manufactured by Dow Corning Toray Co., Ltd. ”, “BY16-880”, “BY16-152C”, “KF-868”, “KF-865”, “KF-864”, “KF-859”, “KF-393” manufactured by Shin-Etsu Chemical Co., Ltd. , "KF-860", "KF-880", "KF-8004", "KF-8002", "KF-8005", "KF-867", "KF-8021", "KF-869", " KF-861", "X-22-343", "KF-101", "X-22-2000", "X-22-4741", "KF-1002", "KF-2001", "X- 22-3701E”, “X-22-164”, “X-22-164A”, “X-22-164B”, “X-22-164AS”, “X-22-2445” and the like.

<A-2-4. Fluorine-based additive>
Any appropriate fluorine-based additive can be adopted as the fluorine-based additive as long as it does not impair the effects of the present invention. As such a fluorine-based additive, preferably at least one selected from a fluorine-containing compound, a hydroxyl group-containing fluorine-based compound, and a crosslinkable functional group-containing fluorine-based compound can be used.

The fluorine-based additive may be used alone or in combination of two or more.

The fluorine-containing compound includes, for example, a compound having a fluoroaliphatic hydrocarbon skeleton, a fluorine-containing organic compound obtained by copolymerizing an organic compound and a fluorine compound, and a fluorine-containing compound containing an organic compound. Examples of the fluoroaliphatic hydrocarbon skeleton include fluoroC1-C10 alkanes such as fluoromethane, fluoroethane, fluoropropane, fluoroisopropane, fluorobutane, fluoroisobutane, fluoro-t-butane, fluoropentane, and fluorohexane. be done. Commercially available products of such fluorine-containing compounds include, for example, Surflon series leveling agents manufactured by AGC Seimi Chemical Co., Ltd. ("S-242", "S-243", "S-420", " S-611", "S-651", "S-386", etc.), BYK series leveling agents manufactured by BYK-Chemie Japan Co., Ltd. ("BYK-340", etc.), Algin Chemie AC series leveling agents agents ("AC 110a", "AC 100a", etc.), Megafac series leveling agents manufactured by DIC Corporation ("Megafac F-114", "Megafac F-410", "Megafac F-444" , "Megafuck EXP TP-2066", "Megafuck F-430", "Megafuck F-472SF", "Megafuck F-477", "Megafuck F-552", "Megafuck F-553", "Megafuck F-554", "Megafuck F-555", "Megafuck R-94", "Megafuck RS-72-K", "Megafuck RS-75", "Megafuck F-556", "Megafac EXP TF-1367", "Megafac EXP TF-1437", "Megafac F-558", "Megafac EXP TF-1537", etc.), Sumitomo 3M's FC series leveling agents ( "FC-4430", "FC-4432", etc.), Futergent series leveling agents manufactured by NEOS Co., Ltd. ("Ftergent 100", "Ftergent 100C", "Ftergent 110", "Ftergent 150") , “Ftergent 150CH”, “Ftergent AK”, “Ftergent 501”, “Ftergent 250”, “Ftergent 251”, “Ftergent 222F”, “Ftergent 208G”, “Ftergent 300” , “Futagent 310”, “Futagent 400SW”, etc.), PF series leveling agents manufactured by Kitamura Chemical Industry Co., Ltd. (“PF-136A”, “PF-156A”, “PF-151N”, “PF- 636”, “PF-6320”, “PF-656”, “PF-6520”, “PF-651”, “PF-652”, “PF-3320”, etc.).

As the hydroxyl group-containing fluorine-based compound, for example, conventionally known resins can be used. No. 97/11130 pamphlet, and International Publication No. 96/26254 pamphlet. Other hydroxyl group-containing fluororesins include, for example, JP-A-8-231919, JP-A-10-265731, JP-A-10-204374, JP-A-8-12922, and the like. A polymer etc. are mentioned. In addition, a copolymer of a compound having a fluorinated alkyl group in a hydroxyl group-containing compound, a fluorine-containing organic compound obtained by copolymerizing a fluorine-containing compound in a hydroxyl group-containing compound, a fluorine-containing compound containing a hydroxyl group-containing organic compound, and the like. Examples of such hydroxyl group-containing fluorine-based compounds include commercially available products such as "Lumiflon" (manufactured by Asahi Glass Co., Ltd.), "Cefral Coat" (manufactured by Central Glass Co., Ltd.), and "Zaflon" (trade name). (manufactured by Toagosei Co., Ltd.), trade name "Zeffle" (manufactured by Daikin Industries, Ltd.), trade name "Megafac F-571" and "Fluonate" (manufactured by DIC Corporation).

Examples of crosslinkable functional group-containing fluorine-based compounds include carboxylic acid compounds having a fluorinated alkyl group such as perfluorooctanoic acid, and compounds having a crosslinkable functional group-containing compound having a fluorinated alkyl group. Polymers, fluorine-containing organic compounds obtained by copolymerizing fluorine-containing compounds with crosslinkable functional group-containing compounds, fluorine-containing compounds containing crosslinkable functional group-containing compounds, and the like. Examples of such crosslinkable functional group-containing fluorine-based compounds include commercially available products such as "Megafac F-570", "Megafac RS-55", "Megafac RS-56", and "Megafac RS-72-K", "Megafac RS-75", "Megafac RS-76-E", "Megafac RS-76-NS", "Megafac RS-78", "Megafac RS-90" (manufactured by DIC Corporation).

By using a low-molecular-weight polyol together with a silicone-based additive and/or a fluorine-based additive, it does not peel off from the adherend more easily, and even when stored for a long period of time in a harsh environment, it does not become heavy over time. It is possible to provide a surface protection film that can more sufficiently suppress detachment and has sufficiently low contamination of the surface of an adherend when attached to the adherend.

When a low-molecular-weight polyol and a silicone-based additive and/or a fluorine-based additive are used in combination, the content of the low-molecular-weight polyol in the pressure-sensitive adhesive composition is preferably 0.01 parts by weight with respect to 100 parts by weight of the base polymer. 50 parts by weight, more preferably 0.05 parts by weight to 25 parts by weight, still more preferably 0.07 parts by weight to 30 parts by weight, still more preferably 0.1 parts by weight to 20 parts by weight more preferably 0.3 to 15 parts by weight, particularly preferably 0.5 to 10 parts by weight, and most preferably 0.7 to 7.0 parts by weight. When a low-molecular-weight polyol and a silicone-based additive and/or a fluorine-based additive are used in combination, if the content of the low-molecular-weight polyol in the pressure-sensitive adhesive composition is within the above range, the surface protective film of the present invention can be applied. It is not easily peeled off from the body, and even if the initial peeling force after sticking to the adherend is large, heavy peeling over time can be more sufficiently suppressed, and the adherend by sticking to the adherend The effect that the contamination of the body surface is sufficiently low can be further exhibited.

When a low-molecular-weight polyol and a silicone-based additive and/or a fluorine-based additive are used in combination, the content of the silicone-based additive and/or the fluorine-based additive in the pressure-sensitive adhesive composition is based on 100 parts by weight of the base polymer, silicone The total amount of additive and fluorine additive is preferably 0.001 to 50 parts by weight, more preferably 0.005 to 25 parts by weight, and still more preferably 0.01 part by weight. 10 parts by weight, more preferably 0.01 part by weight to 1 part by weight, still more preferably 0.01 part by weight to 0.50 part by weight, and particularly preferably 0.01 part by weight to 0.01 part by weight. 30 parts by weight, most preferably 0.01 to 0.10 parts by weight. When a low-molecular-weight polyol and a silicone-based additive and/or a fluorine-based additive are used in combination, if the content of the silicone-based additive and/or the fluorine-based additive in the pressure-sensitive adhesive composition is within the above range, the present invention The surface protective film of is not easily peeled off from the adherend, and even if the initial peeling force after being attached to the adherend is large, it can more sufficiently suppress heavy peeling over time, and the adherend The effect of sufficiently lower contamination of the surface of the adherend due to sticking to the surface can be further exhibited. Specifically, it is as follows.

When the low-molecular-weight polyol and the silicone additive are used in combination but the fluorine additive is not used in combination, the content of the silicone additive in the pressure-sensitive adhesive composition is preferably 0.001 per 100 parts by weight of the base polymer. parts by weight to 50 parts by weight, more preferably 0.005 parts by weight to 25 parts by weight, still more preferably 0.01 parts by weight to 10 parts by weight, still more preferably 0.01 parts by weight to 1 part by weight parts, more preferably 0.01 to 0.50 parts by weight, particularly preferably 0.01 to 0.30 parts by weight, and most preferably 0.01 to 0.10 parts by weight. weight part. When a low-molecular-weight polyol and a silicone-based additive are used in combination, but the fluorine-based additive is not used in combination, if the content of the silicone-based additive in the pressure-sensitive adhesive composition is within the above range, the surface protective film of the present invention is It does not peel off from the adherend more easily, and even if the initial peeling force after sticking to the adherend is large, it is possible to more sufficiently suppress heavy peeling over time, and the adhesion by sticking to the adherend is possible. The effect that the contamination of the surface of the adherend is sufficiently low can be further exhibited.

When the low-molecular-weight polyol and the fluorine-based additive are used in combination but the silicone-based additive is not used in combination, the content of the fluorine-based additive in the pressure-sensitive adhesive composition is preferably 0.001 per 100 parts by weight of the base polymer. parts by weight to 50 parts by weight, more preferably 0.005 parts by weight to 25 parts by weight, still more preferably 0.01 parts by weight to 10 parts by weight, still more preferably 0.01 parts by weight to 1 part by weight parts, more preferably 0.01 to 0.50 parts by weight, particularly preferably 0.01 to 0.30 parts by weight, and most preferably 0.01 to 0.10 parts by weight. weight part. When the low-molecular-weight polyol and the fluorine-based additive are used in combination, but the silicone-based additive is not used in combination, the surface protective film of the present invention can be obtained by: It does not peel off from the adherend more easily, and even if the initial peeling force after sticking to the adherend is large, it is possible to more sufficiently suppress heavy peeling over time, and the adhesion by sticking to the adherend is possible. The effect that the contamination of the surface of the adherend is sufficiently low can be further exhibited.

When a low-molecular-weight polyol, a silicone additive, and a fluorine additive are used in combination, the total content of the silicone additive and the fluorine additive relative to 100 parts by weight of the base polymer is preferably 0.001 part by weight to 50 parts by weight. parts, more preferably 0.005 to 25 parts by weight, still more preferably 0.01 to 10 parts by weight, still more preferably 0.01 to 1 part by weight, and further It is preferably 0.01 to 0.50 parts by weight, particularly preferably 0.01 to 0.30 parts by weight, most preferably 0.01 to 0.10 parts by weight. When a low-molecular-weight polyol, a silicone-based additive, and a fluorine-based additive are used in combination, if the total content of the silicone-based additive and the fluorine-based additive in the pressure-sensitive adhesive composition is within the above range, the surface of the present invention The protective film is not easily peeled off from the adherend, and even if the initial peeling force after being attached to the adherend is large, the protective film can sufficiently suppress heavy peeling over time, and can be adhered to the adherend. The effect that the contamination of the surface of the adherend due to application is sufficiently low can be further exhibited.

<A-2-5. Urethane resin>
The above-described urethane prepolymer and polyol as the base polymer can each be combined with the polyfunctional isocyanate compound (B) to become components of the composition for forming the urethane-based resin. By adopting the above components as the components of the composition for forming the urethane-based resin, the surface protective film of the present invention can be adhered to the adherend without being easily peeled off from the adherend. Even if the subsequent initial peeling force is large, heavy peeling over time can be sufficiently suppressed, and the effect of sufficiently low contamination of the surface of the adherend due to attachment to the adherend can be further exhibited.

The composition for forming the urethane-based resin may contain any appropriate other component within a range that does not impair the effects of the present invention. Such components include, for example, resin components other than urethane-based resins, tackifiers, inorganic fillers, organic fillers, metal powders, pigments, foils, softeners, anti-aging agents, conductive agents, and UV absorbers. agents, antioxidants, light stabilizers, surface lubricants, leveling agents, corrosion inhibitors, heat stabilizers, polymerization inhibitors, lubricants, solvents, catalysts and the like.

The composition for forming the urethane-based resin preferably contains deterioration inhibitors such as antioxidants, ultraviolet absorbers, and light stabilizers. Since the composition for forming the urethane-based resin contains an anti-degradation agent, even if the formed pressure-sensitive adhesive layer is stored in a heated state after being attached to the adherend, adhesive residue is left on the adherend. It can be excellent in adhesive residue prevention, such as being difficult to apply. Only one kind of anti-degradation agent may be used, or two or more kinds thereof may be used. Antioxidants are particularly preferred as deterioration inhibitors.

Antioxidants include, for example, radical chain inhibitors and peroxide decomposers.

Examples of radical chain inhibitors include phenol antioxidants and amine antioxidants.

Examples of peroxide decomposers include sulfur-based antioxidants and phosphorus-based antioxidants.

Examples of phenolic antioxidants include monophenolic antioxidants, bisphenolic antioxidants, polymeric phenolic antioxidants, and the like.

Examples of monophenol antioxidants include 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, stearin-β-( 3,5-di-t-butyl-4-hydroxyphenyl)propionate and the like.

Examples of bisphenol antioxidants include 2,2'-methylenebis(4-methyl-6-t-butylphenol), 2,2'-methylenebis(4-ethyl-6-t-butylphenol), 4,4' -thiobis(3-methyl-6-t-butylphenol), 4,4′-butylidenebis(3-methyl-6-t-butylphenol), 3,9-bis[1,1-dimethyl-2-[β-( 3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl]2,4,8,10-tetraoxaspiro[5,5]undecane and the like.

Examples of polymeric phenolic antioxidants include 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane, 1,3,5-trimethyl-2,4, 6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, tetrakis-[methylene-3-(3′,5′-di-t-butyl-4′-hydroxyphenyl)propionate]methane , bis[3,3′-bis-(4′-hydroxy-3′-t-butylphenyl)butyric acid]glycol ester, 1,3,5-tris(3′,5′-di-t-butyl -4′-Hydroxybenzyl)-S-triazine-2,4,6-(1H,3H,5H)trione, tocopherol and the like.

Examples of sulfur-based antioxidants include dilauryl 3,3'-thiodipropionate, dimyristyl 3,3'-thiodipropionate, and distearyl 3,3'-thiodipropionate.

Phosphorus antioxidants include, for example, triphenylphosphite, diphenylisodecylphosphite, and phenyldiisodecylphosphite.

Examples of ultraviolet absorbers include benzophenone-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, salicylic acid-based ultraviolet absorbers, oxalic acid anilide-based ultraviolet absorbers, cyanoacrylate-based ultraviolet absorbers, and triazine-based ultraviolet absorbers. be done.

Benzophenone-based UV absorbers include, for example, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, 2,2' -dihydroxy-4-dimethoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, bis(2-methoxy-4-hydroxy-5-benzoylphenyl ) methane and the like.

Benzotriazole-based UV absorbers include, for example, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-5'-tert-butylphenyl)benzotriazole, 2-( 2′-hydroxy-3′,5′-di-tert-butylphenyl)benzotriazole, 2-(2′-hydroxy-3′-tert-butyl-5′-methylphenyl)-5-chlorobenzotriazole, 2 -(2'-hydroxy-3',5'-di-tert-butylphenyl)5-chlorobenzotriazole, 2-(2'-hydroxy-3',5'-di-tert-amylphenyl)benzotriazole, 2-(2'-hydroxy-4'-octoxyphenyl)benzotriazole, 2-[2'-hydroxy-3'-(3'',4'',5'',6'',-tetrahydrophthalimidomethyl )-5′-methylphenyl]benzotriazole, 2,2′methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl)phenol], 2- (2'-Hydroxy-5'-methacryloxyphenyl)-2H-benzotriazole and the like.

Examples of salicylic acid-based ultraviolet absorbers include phenyl salicylate, p-tert-butylphenyl salicylate, and p-octylphenyl salicylate.

Examples of cyanoacrylate ultraviolet absorbers include 2-ethylhexyl-2-cyano-3,3'-diphenyl acrylate and ethyl-2-cyano-3,3'-diphenyl acrylate.

Examples of light stabilizers include hindered amine light stabilizers and ultraviolet stabilizers.

Examples of hindered amine light stabilizers include bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, methyl -1,2,2,6,6-pentamethyl-4-piperidyl sebacate and the like.

UV stabilizers include, for example, nickel bis(octylphenyl) sulfide, [2,2′-thiobis(4-tert-octylphenolate)]-n-butylamine nickel, nickel complex-3,5-di-tert- Butyl-4-hydroxybenzyl-phosphate monoethylate, nickel-dibutyldithiocarbamate, benzoate type quenchers, nickel-dibutyldithiocarbamate and the like.

[A-2-5-a. Urethane resin formed from composition containing urethane prepolymer and polyfunctional isocyanate compound (B)]
A urethane-based resin formed from a composition containing a urethane prepolymer and a polyfunctional isocyanate compound (B) is, for example, formed from a composition containing a polyurethane polyol as a urethane prepolymer and a polyfunctional isocyanate compound (B). and urethane-based resins.

Only one type of urethane prepolymer may be used, or two or more types may be used.

The number of polyfunctional isocyanate compounds (B) may be one, or two or more.

As the polyfunctional isocyanate compound (B), any suitable polyfunctional isocyanate compound that can be used in the urethanization reaction can be adopted. Examples of such polyfunctional isocyanate compounds (B) include polyfunctional aliphatic isocyanate compounds, polyfunctional alicyclic isocyanates, and polyfunctional aromatic isocyanate compounds.

Polyfunctional aliphatic isocyanate compounds include, for example, trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, 2,4, 4-trimethylhexamethylene diisocyanate and the like.

Examples of polyfunctional alicyclic isocyanate compounds include 1,3-cyclopentene diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated tetramethylxylylene diisocyanate, and the like.

Polyfunctional aromatic diisocyanate compounds include, for example, phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 2,2′-diphenylmethane diisocyanate, 4,4′-diphenylmethane diisocyanate, 4 ,4'-toluidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, xylylene diisocyanate and the like.

Examples of the polyfunctional isocyanate compound (B) include trimethylolpropane adducts of various polyfunctional isocyanate compounds such as those described above, water-reacted biuret forms, trimers having an isocyanurate ring, and the like. Moreover, you may use these together.

The composition containing the urethane prepolymer and the polyfunctional isocyanate compound (B) may contain any appropriate other component as long as the effects of the present invention are not impaired. Such other components include, for example, resin components other than polyurethane resins, tackifiers, inorganic fillers, organic fillers, metal powders, pigments, foils, softeners, anti-aging agents, conductive agents, UV absorbers, antioxidants, light stabilizers, surface lubricants, leveling agents, corrosion inhibitors, heat stabilizers, polymerization inhibitors, lubricants, solvents, catalysts and the like.

As a method for forming a polyurethane-based resin from a composition containing a urethane prepolymer and a polyfunctional isocyanate compound (B), any method can be used as long as it is a method for producing a polyurethane-based resin using a so-called "urethane prepolymer" as a raw material. suitable manufacturing method can be adopted.

The number average molecular weight Mn of the urethane prepolymer is preferably from 3,000 to 1,000,000.

The equivalent ratio of NCO groups to OH groups in the urethane prepolymer and the polyfunctional isocyanate compound (B) is preferably 5.0 or less, more preferably 0.01 to 4.75, as NCO groups/OH groups. more preferably 0.02 to 4.5, particularly preferably 0.03 to 4.25, and most preferably 0.05 to 4.0. When the NCO group/OH group equivalent ratio is within the above range, the surface protective film of the present invention is not easily peeled off from the adherend, and has a large initial peeling force after being attached to the adherend. However, it is possible to sufficiently suppress heavy peeling over time, and the effect of sufficiently low contamination of the surface of the adherend due to attachment to the adherend can be further exhibited.

The content of the polyfunctional isocyanate compound (B) is preferably 0.01% by weight to 30% by weight, more preferably 0.05% by weight, relative to the urethane prepolymer. to 25% by weight, more preferably 0.1% to 20% by weight, particularly preferably 0.5% to 17.5% by weight, and most preferably 1% to 15% by weight. be. If the content of the polyfunctional isocyanate compound (B) is within the above range, the surface protective film of the present invention will not be easily peeled off from the adherend, and the initial peel strength after being attached to the adherend will be It is possible to sufficiently suppress heavy peeling over time even if it is large, and it is possible to exhibit the effect of sufficiently low contamination of the surface of the adherend by sticking to the adherend.

[A-2-5-b. Urethane resin formed from composition containing polyol and polyfunctional isocyanate compound (B)]
Specifically, the urethane resin formed from the composition containing the polyol and the polyfunctional isocyanate compound (B) is preferably obtained by curing the composition containing the polyol and the polyfunctional isocyanate compound (B). It is a urethane resin that can be

Only one kind of polyol may be used, or two or more kinds thereof may be used.

The number of polyfunctional isocyanate compounds (B) may be one, or two or more.

As the polyfunctional isocyanate compound (B), those mentioned above can be used.

The equivalent ratio of NCO groups to OH groups in the polyol (A) and the polyfunctional isocyanate compound (B) is preferably 5.0 or less, more preferably 0.1 to 3.0, as NCO groups/OH groups. is more preferably 0.2 to 2.5, particularly preferably 0.3 to 2.25, and most preferably 0.5 to 2.0. When the NCO group/OH group equivalent ratio is within the above range, the surface protective film of the present invention is not easily peeled off from the adherend, and has a large initial peeling force after being attached to the adherend. However, it is possible to sufficiently suppress heavy peeling over time, and the effect of sufficiently low contamination of the surface of the adherend due to attachment to the adherend can be further exhibited.

The content of the polyfunctional isocyanate compound (B) is preferably 1.0% by weight to 30% by weight, more preferably 1.5% by weight to 27% by weight, based on the polyol. % by weight, more preferably 2.0% to 25% by weight, particularly preferably 2.3% to 23% by weight, and most preferably 2.5% to 20% by weight. If the content of the polyfunctional isocyanate compound (B) is within the above range, the surface protective film of the present invention will not be easily peeled off from the adherend, and the initial peel strength after being attached to the adherend will be It is possible to sufficiently suppress heavy peeling over time even if it is large, and it is possible to exhibit the effect of sufficiently low contamination of the surface of the adherend by sticking to the adherend.

Specifically, the polyurethane-based resin is preferably formed by curing a composition containing a polyol and a polyfunctional isocyanate compound (B). As a method for forming a urethane-based resin by curing a composition containing a polyol and a polyfunctional isocyanate compound (B), a urethanization reaction method using bulk polymerization, solution polymerization, or the like does not impair the effects of the present invention. Any suitable method can be employed within the range.

A catalyst is preferably used to cure the composition containing the polyol and the polyfunctional isocyanate compound (B). Examples of such catalysts include organometallic compounds and tertiary amine compounds.

Examples of organometallic compounds include iron-based compounds, tin-based compounds, titanium-based compounds, zirconium-based compounds, lead-based compounds, cobalt-based compounds, and zinc-based compounds. Among these, iron-based compounds and tin-based compounds are preferable in terms of reaction speed and pot life of the pressure-sensitive adhesive layer.

Examples of iron-based compounds include iron acetylacetonate and iron 2-ethylhexanoate.

Examples of tin compounds include dibutyltin dichloride, dibutyltin oxide, dibutyltin dibromide, dibutyltin maleate, dibutyltin dilaurate, dibutyltin diacetate, dibutyltin sulfide, tributyltin methoxide, tributyltin acetate, triethyltin ethoxide, tributyltin ethoxide, dioctyltin oxide, dioctyltin dilaurate, tributyltin chloride, tributyltin trichloroacetate, tin 2-ethylhexanoate and the like.

Titanium compounds include, for example, dibutyltitanium dichloride, tetrabutyltitanate, butoxytitanium trichloride and the like.

Zirconium-based compounds include, for example, zirconium naphthenate and zirconium acetylacetonate.

Examples of lead-based compounds include lead oleate, lead 2-ethylhexanoate, lead benzoate, and lead naphthenate.

Examples of cobalt-based compounds include cobalt 2-ethylhexanoate and cobalt benzoate.

Examples of zinc-based compounds include zinc naphthenate and zinc 2-ethylhexanoate.

Tertiary amine compounds include, for example, triethylamine, triethylenediamine, 1,8-diazabisic-(5,4,0)-undecene-7 and the like.

Only one kind of catalyst may be used, or two or more kinds thereof may be used. Moreover, a catalyst and a cross-linking retarder may be used in combination. The amount of catalyst is preferably 0.005 wt% to 1.00 wt%, more preferably 0.01 wt% to 0.75 wt%, more preferably 0.01 wt%, relative to the polyol. % to 0.50% by weight, particularly preferably 0.01% to 0.20% by weight. If the amount of the catalyst is within the above range, the surface protective film of the present invention will not be easily peeled off from the adherend, and even if the initial peeling force after being attached to the adherend is large, the film will not become heavy over time. Detachment can be sufficiently suppressed, and the effect of sufficiently low contamination of the surface of an adherend due to attachment to the adherend can be further exhibited.

The composition containing the polyol and the polyfunctional isocyanate compound (B) may contain any appropriate other component as long as the effects of the present invention are not impaired. Such other components include, for example, resin components other than polyurethane resins, tackifiers, inorganic fillers, organic fillers, metal powders, pigments, foils, softeners, anti-aging agents, conductive agents, UV absorbers, antioxidants, light stabilizers, surface lubricants, leveling agents, corrosion inhibitors, heat stabilizers, polymerization inhibitors, lubricants, solvents, catalysts and the like.

<A-2-6. Fatty acid ester>
The adhesive composition preferably contains a fatty acid ester. Only one kind of fatty acid ester may be used, or two or more kinds thereof may be used. When the pressure-sensitive adhesive composition contains a fatty acid ester, the surface protective film of the present invention will not be easily peeled off from the adherend, and even if the initial peeling force after sticking to the adherend is large, the film will not become heavy over time. Detachment can be sufficiently suppressed, and the effect of sufficiently low contamination of the surface of an adherend due to attachment to the adherend can be further exhibited.

The number average molecular weight Mn of the fatty acid ester is preferably 100 to 800, more preferably 150 to 750, still more preferably 200 to 700, particularly preferably 200 to 650, most preferably 200 to 600. is. If the number average molecular weight Mn of the fatty acid ester is within the above range, the surface protective film of the present invention will not be easily peeled off from the adherend, and the initial peeling force after being attached to the adherend will be large. Also, it is possible to sufficiently suppress heavy peeling with the passage of time, and it is possible to further exhibit the effect of sufficiently low contamination of the surface of the adherend by sticking to the adherend.

As the fatty acid ester, any suitable fatty acid ester can be adopted as long as it does not impair the effects of the present invention. Examples of such fatty acid esters include polyoxyethylene bisphenol A laurate, butyl stearate, 2-ethylhexyl palmitate, 2-ethylhexyl stearate, monoglyceride behenate, cetyl 2-ethylhexanoate, and myristic acid. Isopropyl, isopropyl palmitate, cholesteryl isostearate, lauryl methacrylate, methyl cocoate, methyl laurate, methyl oleate, methyl stearate, myristyl myristate, octyldodecyl myristate, pentaerythritol monooleate, pentaerythritol monostearate , pentaerythritol tetrapalmitate, stearyl stearate, isotridecyl stearate, 2-ethylhexanoic acid triglyceride, butyl laurate, octyl oleate and the like.

When the adhesive composition contains a fatty acid ester, the content of the fatty acid ester is preferably 0.01 to 50 parts by weight, more preferably 0.05 to 50 parts by weight, relative to 100 parts by weight of the base polymer. 45 parts by weight, more preferably 0.1 to 40 parts by weight, more preferably 0.3 to 35 parts by weight, still more preferably 0.5 to 30 parts by weight , particularly preferably 0.5 to 25 parts by weight, most preferably 0.5 to 20 parts by weight. If the content of the fatty acid ester is within the above range with respect to 100 parts by weight of the base polymer, the surface protective film of the present invention will not be easily peeled off from the adherend, and the initial Even if the peeling force of is large, heavy peeling over time can be sufficiently suppressed, and the effect of sufficiently low contamination of the adherend surface due to attachment to the adherend can be further exhibited.

<A-2-7. Other Ingredients>
The pressure-sensitive adhesive composition may contain any appropriate other component as long as the effects of the present invention are not impaired. Such other components include, for example, other resin components, tackifiers, inorganic fillers, organic fillers, metal powders, pigments, foils, softeners, anti-aging agents, conductive agents, and UV absorbers. , antioxidants, light stabilizers, surface lubricants, leveling agents, corrosion inhibitors, heat stabilizers, polymerization inhibitors, lubricants, solvents, catalysts and the like.

The adhesive composition may contain an ionic liquid containing a fluoroorganic anion. By including an ionic liquid containing a fluoroorganic anion in the pressure-sensitive adhesive composition, it is possible to provide a pressure-sensitive adhesive composition with extremely excellent antistatic properties. Only one kind of such ionic liquid may be used, or two or more kinds thereof may be used.

In the present invention, the ionic liquid means a molten salt (ionic compound) that exhibits a liquid state at 25°C.

As the ionic liquid, any appropriate ionic liquid can be adopted as long as it contains a fluoroorganic anion, as long as it does not impair the effects of the present invention. Such an ionic liquid is preferably an ionic liquid composed of a fluoroorganic anion and an onium cation. By employing an ionic liquid composed of a fluoroorganic anion and an onium cation as the ionic liquid, it is possible to provide a pressure-sensitive adhesive composition with extremely excellent antistatic properties.

As the onium cation that can constitute the ionic liquid, any suitable onium cation can be adopted as long as the effects of the present invention are not impaired. Such an onium cation is preferably at least one selected from nitrogen-containing onium cations, sulfur-containing onium cations, and phosphorus-containing onium cations. By selecting these onium cations, it is possible to provide a pressure-sensitive adhesive composition with extremely excellent antistatic properties.

As the fluoroorganic anion that can constitute the ionic liquid, any suitable fluoroorganic anion can be adopted as long as the effects of the present invention are not impaired. Such fluoroorganic anions may be fully fluorinated (perfluorinated) or partially fluorinated.

Such fluoroorganic anions include, for example, fluorinated arylsulfonates, perfluoroalkanesulfonates, bis(fluorosulfonyl)imides, bis(perfluoroalkanesulfonyl)imides, cyanoperfluoroalkanesulfonylamides, bis(cyano) perfluoroalkanesulfonylmethide, cyano-bis-(perfluoroalkanesulfonyl)methide, tris(perfluoroalkanesulfonyl)methide, trifluoroacetate, perfluoroalkylate, tris(perfluoroalkanesulfonyl)methide, (perfluoroalkane sulfonyl)trifluoroacetamide and the like.

A commercially available ionic liquid may be used, but it is also possible to synthesize it as follows. The method for synthesizing the ionic liquid is not particularly limited as long as the desired ionic liquid can be obtained. Publishing), the halide method, the hydroxide method, the acid ester method, the complexation method, and the neutralization method are used.

The blending amount of the ionic liquid varies depending on the compatibility between the polymer and the ionic liquid used, and cannot be unconditionally defined. It is from 0.01 to 40 parts by weight, more preferably from 0.01 to 30 parts by weight, and particularly preferably from 0.01 to 20 parts by weight. parts, most preferably 0.01 to 10 parts by weight. By adjusting the blending amount of the ionic liquid within the above range, it is possible to provide a pressure-sensitive adhesive composition having extremely excellent antistatic properties. If the amount of the ionic liquid is less than 0.01 part by weight, it may not be possible to obtain sufficient antistatic properties. If the amount of the ionic liquid exceeds 50 parts by weight, contamination of the adherend tends to increase.

The pressure-sensitive adhesive composition may contain a modified silicone oil as long as the effects of the present invention are not impaired. By including the modified silicone oil in the pressure-sensitive adhesive composition, an antistatic effect can be exhibited. In particular, by using it together with an ionic liquid, the effect of antistatic properties can be exhibited more effectively.

When the pressure-sensitive adhesive composition contains modified silicone oil, the content is preferably 0.001 to 50 parts by weight, more preferably 0.005 to 40 parts by weight, relative to 100 parts by weight of the base polymer. parts by weight, more preferably 0.007 to 30 parts by weight, particularly preferably 0.008 to 20 parts by weight, and most preferably 0.01 to 10 parts by weight. By adjusting the content of the modified silicone oil within the above range, the antistatic effect can be exhibited more effectively.

As the modified silicone oil, any appropriate modified silicone oil can be adopted as long as the effects of the present invention are not impaired. Examples of such modified silicone oils include modified silicone oils available from Shin-Etsu Chemical Co., Ltd.

The modified silicone oil is preferably a polyether-modified silicone oil. By employing the polyether-modified silicone oil, the antistatic effect can be exhibited more effectively.

Examples of the polyether-modified silicone oil include side-chain-type polyether-modified silicone oil and both-ends-type polyether-modified silicone oil. Among these, double-ended polyether-modified silicone oil is preferable in that the effect of antistatic properties can be exhibited sufficiently and more effectively.

≪≪B. Application≫≫
The surface protective film of the present invention is not easily peeled off from the adherend, and can sufficiently suppress heavy peeling over time even if the initial peeling force after being attached to the adherend is large. It is possible to exhibit the effect that the contamination of the surface of the adherend by sticking to the surface is sufficiently low. Therefore, it can be suitably used for surface protection of optical members and electronic members. The optical member of the present invention has the surface protective film of the present invention adhered thereto. The electronic member of the present invention has the surface protection film of the present invention adhered thereto.

EXAMPLES The present invention will be specifically described below with reference to Examples, but the present invention is not limited to these Examples. The tests and evaluation methods used in Examples and the like are as follows. "Parts" means "parts by weight" unless otherwise specified, and "%" means "% by weight" unless otherwise specified.

<Peeling force A from the glass plate (after standing at a temperature of 23° C. for 30 minutes)>
The pressure-sensitive adhesive layer side of the surface protective film (width 25 mm × length 140 mm) from which the separator was removed was pasted to a glass plate (soda lime glass, manufactured by Matsunami Glass Industry Co., Ltd.) with a 2 kg hand roller one reciprocation, and an environment of 23 ° C. It was left under temperature for 30 minutes.
The evaluation sample obtained as described above was measured with a tensile tester. As the tensile tester, a trade name "Autograph AG-Xplus HS 6000 mm/min high speed model (AG-50NX plus)" manufactured by Shimadzu Corporation was used. A sample for evaluation was set in a tensile tester, and a tensile test was started. Specifically, the load when the surface protective film was peeled off from the glass plate was measured, and the average load at that time was defined as the peeling force A of the surface protective film from the glass plate. The conditions of the tensile test were: test environment temperature: 23° C., peeling angle: 180 degrees, peeling speed (tensile speed): 300 mm/min.

<Peeling force B from the glass plate (after standing at a temperature of 100° C. for 2 days)>
The pressure-sensitive adhesive layer side of the surface protective film (width 25 mm × length 140 mm) from which the separator was removed was pasted to a glass plate (soda lime glass, manufactured by Matsunami Glass Industry Co., Ltd.) with a 2 kg hand roller one reciprocation, and the temperature was 100 ° C. It was left in the environment for two days.
The evaluation sample obtained as described above was measured with a tensile tester. As the tensile tester, a trade name "Autograph AG-Xplus HS 6000 mm/min high speed model (AG-50NX plus)" manufactured by Shimadzu Corporation was used. A sample for evaluation was set in a tensile tester, and a tensile test was started. Specifically, the load when the surface protective film was peeled off from the glass plate was measured, and the average load at that time was defined as the peeling force B of the surface protective film from the glass plate. The conditions of the tensile test were: test environment temperature: 23° C., peeling angle: 180 degrees, peeling speed (tensile speed): 300 mm/min.

<Peeling force C from the glass plate (after being left at a temperature of 23° C. for 7 days)>
The pressure-sensitive adhesive layer side of the surface protective film (width 25 mm × length 140 mm) from which the separator was removed was pasted to a glass plate (soda lime glass, manufactured by Matsunami Glass Industry Co., Ltd.) with a 2 kg hand roller one reciprocation, and the temperature was 23 ° C. It was left in the environment for 7 days.
The evaluation sample obtained as described above was measured with a tensile tester. As the tensile tester, a trade name "Autograph AG-Xplus HS 6000 mm/min high speed model (AG-50NX plus)" manufactured by Shimadzu Corporation was used. A sample for evaluation was set in a tensile tester, and a tensile test was started. Specifically, the load when the surface protective film was peeled off from the glass plate was measured, and the average load at that time was defined as the peeling force C of the surface protective film from the glass plate. The conditions of the tensile test were: test environment temperature: 23° C., peeling angle: 180 degrees, peeling speed (tensile speed): 300 mm/min.

<Residual adhesion rate to glass plate at 23°C>
The pressure-sensitive adhesive layer side of the surface protection film from which the separator was removed was attached to the entire surface of the glass plate (manufactured by Matsunami Glass, 1.35 mm × 10 cm × 10 cm) with a 2-kg hand roller one reciprocation, temperature 23 ° C., humidity 55% RH. After being stored for 24 hours in an atmosphere of , the surface protective film was peeled off at a speed of 0.3 m/min to prepare a treated glass plate.
Subsequently, on the surface of the treated glass plate from which the surface protective film was peeled off, a 19 mm wide No. A 31B tape (manufactured by Nitto Denko Corporation, substrate thickness: 25 μm) was adhered with a 2-kg hand roller one reciprocation under an atmosphere of 23° C. and 55% RH. After curing for 30 minutes in an atmosphere with a temperature of 23 ° C. and a humidity of 55% RH, a tensile tester (trade name “Autograph AG-Xplus HS 6000 mm / min high speed model (AG-50NX plus)” manufactured by Shimadzu Corporation). was used, the peel angle was 180 degrees, the peel speed was 300 mm/min, and the adhesive force a was measured.
Separately, a glass plate (Matsunami Glass Co., Ltd., 1.35 mm×10 cm×10 cm) not subjected to the bonding and peeling treatment of the surface protection film as described above was also subjected to a No. 19 mm wide glass plate in the same manner as described above. The adhesion b of the 31B tape was measured.
The residual adhesion rate was calculated by the following formula.
Residual adhesion rate (%) = (adhesive strength a/adhesive strength b) x 100
This residual adhesion rate is an index of how much the component of the pressure-sensitive adhesive layer of the surface protective film is transferred to the surface of the adherend and contaminates it. The higher the residual adhesion rate, the less likely the surface protection film is to contaminate the surface of the adherend with the components of the pressure-sensitive adhesive layer. It is a surface protection film that is easily contaminated with

<Storage modulus>
(Sample preparation method)
The pressure-sensitive adhesive composition was applied to the release-treated surface of a 38 μm-thick polyester film (trade name: MRF, manufactured by Mitsubishi Chemical Corporation) whose one side was release-treated with silicone so that the thickness after drying with a fountain roll was 50 μm, It was cured and dried under the conditions of a drying temperature of 130° C. and a drying time of 3 minutes. Thus, a pressure-sensitive adhesive layer was produced on the substrate. Next, on the surface of the adhesive layer, a 38 μm-thick polyester film (trade name: MRF, manufactured by Mitsubishi Chemical Corporation) with one side treated with silicone for release is applied so that the release-treated surface of the film faces the adhesive layer side. coated with Thus, a pressure-sensitive adhesive sheet was produced.
(Measuring method)
Only the pressure-sensitive adhesive layer was taken out from the obtained pressure-sensitive adhesive sheet, laminated to a thickness of about 2 mm, and punched into a diameter of 7.9 mm to prepare a cylindrical pellet, which was used as a sample for measurement. A measurement sample was fixed to a φ7.9 mm parallel plate jig, and the storage elastic modulus G′ was calculated using a dynamic viscoelasticity measuring device (manufactured by Rheometrics, ARES). The measurement conditions are as follows. In addition, "a.E+b" described in the table means "a×10 ^b ", as is generally well known.
Measurement: Shear mode Temperature range: -70°C to 150°C
Heating rate: 5°C/min
Frequency: 1Hz

[Production Example 1]
Polypropylene glycol (product name " Sannix PP-2000", manufactured by Sanyo Chemical Co., Ltd.): 150 g, polyester polyol (product name "Kuraray Polyol P-2010", manufactured by Kuraray Co., Ltd.): 150 g, toluene as a solvent (manufactured by Tosoh Corporation): 110 g, dilauric acid as a catalyst Dibutyltin (IV) (manufactured by Wako Pure Chemical Industries, Ltd.): 0.041 g was added, and nitrogen substitution was performed at room temperature for 1 hour while stirring. After that, 33.5 g of hexamethylene diisocyanate (product name “HDI”, manufactured by Tosoh Corporation) was added while stirring under nitrogen flow, and the temperature of the solution in the experimental apparatus was adjusted to 90±2° C. in a water bath. After holding for 4 hours while controlling, 74.9 g of polypropylene glycol (product name “GP1000”, manufactured by Sanyo Kasei Co., Ltd.) was added, and the solution temperature in the experimental apparatus was adjusted to 90 ± 2 ° C. in a water bath. After holding for 2 hours while controlling, hexamethylene diisocyanate (product name "HDI", manufactured by Tosoh Corporation): 25.4 g was added, and the solution temperature in the experimental apparatus was adjusted to 90 ± 2 ° C. in a water bath. It was held for 2 hours while controlling, and a urethane prepolymer solution A was obtained. During the polymerization, toluene was added dropwise as appropriate in order to control the temperature during the polymerization and to prevent deterioration of the stirrability due to an increase in viscosity. The total amount of toluene dropped was 320 g. The solid content concentration of the urethane prepolymer solution A was 50% by weight.

[Example 1]
As shown in Table 1, 100 parts by weight of the urethane prepolymer solution A obtained in Production Example 1 in terms of polymer solid content and an isocyanate-based cross-linking agent (trade name "Coronate HL", manufactured by Nippon Polyurethane Co., Ltd.) were added as solids. 14.6 parts by weight in terms of minutes, 0.5 parts by weight of a heat stabilizer (trade name “Irganox 1010”, manufactured by BASF) in terms of solid content, and low molecular weight polyol (trade name “Sannix GP250”, number The average molecular weight Mn = 250, manufactured by Sanyo Chemical Industries Co., Ltd.) is 1.0 parts by weight in terms of solid content, and the fluorine-containing polymer (trade name “F-571”, manufactured by DIC Corporation) is 0.05 in terms of solid content. Part by weight and 1 part by weight of fatty acid ester (trade name “Salacos 816”, manufactured by Nisshin OilliO Co., Ltd.) in terms of solid content are blended, and diluted with ethyl acetate so that the total solid content is 45% by weight. to obtain a pressure-sensitive adhesive composition (1).
The obtained pressure-sensitive adhesive composition (1) is applied to a base material made of polyester resin (trade name “T100-75S”, thickness 75 μm, manufactured by Mitsubishi Chemical Corporation) so that the thickness after drying becomes 75 μm, and dried. It was cured and dried under conditions of a temperature of 130° C. and a drying time of 3 minutes. Thus, the adhesive layer (1) formed from the adhesive composition (1) was produced on the substrate.
Next, on the surface of the pressure-sensitive adhesive layer (1) thus obtained, a separator (trade name: "MRF25", thickness: 25 µm, manufactured by Mitsubishi Chemical Co., Ltd.) made of a polyester resin having a thickness of 25 µm and having one surface treated with silicone was applied. The treated surfaces were bonded together to obtain a surface protective film (1).
The obtained surface protective film (1) was aged at room temperature for 7 days and evaluated. The release sheet was removed just prior to evaluation. Table 2 shows the results.

[Example 2]
As shown in Table 1, the blending amount of the isocyanate-based cross-linking agent (trade name "Coronate HL", manufactured by Nippon Polyurethane Co., Ltd.) was 16.0 parts by weight in terms of solid content, and the low molecular weight polyol (trade name "Sannics GP250 ", number average molecular weight Mn = 250, manufactured by Sanyo Chemical Industries Co., Ltd.) was changed to 1.5 parts by weight in terms of solid content. A pressure-sensitive adhesive layer (2) formed from was produced to obtain a surface protective film (2). Table 2 shows the results.

[Example 3]
As shown in Table 1, the blending amount of the isocyanate-based cross-linking agent (trade name "Coronate HL", manufactured by Nippon Polyurethane Co., Ltd.) was 16.6 parts by weight in terms of solid content, and the low molecular weight polyol (trade name "Sannics GP250 ", number average molecular weight Mn = 250, manufactured by Sanyo Chemical Industries Co., Ltd.) was changed to 2.0 parts by weight in terms of solid content. A pressure-sensitive adhesive layer (3) formed from was produced to obtain a surface protective film (3). Table 2 shows the results.

[Example 4]
As shown in Table 1, the blending amount of the isocyanate-based cross-linking agent (trade name “Coronate HL”, manufactured by Nippon Polyurethane Co., Ltd.) was changed to 6.5 parts by weight in terms of solid content, and the fatty acid ester (trade name “Salacos 816 ", manufactured by Nisshin OilliO Co., Ltd.) was performed in the same manner as in Example 1 to prepare an adhesive layer (4) formed from the adhesive composition (4), and a surface protective film (4 ). Table 2 shows the results.

[Example 5]
As shown in Table 1, the compounding amount of the isocyanate-based cross-linking agent (trade name "Coronate HL", manufactured by Nippon Polyurethane Co., Ltd.) was 13.2 parts by weight in terms of solid content, and the low molecular weight polyol (trade name "Sannics GP250 ", number average molecular weight Mn = 250, manufactured by Sanyo Chemical Industries Co., Ltd.) was changed to 3.0 parts by weight in terms of solid content. A pressure-sensitive adhesive layer (5) formed from was produced to obtain a surface protective film (5). Table 2 shows the results.

[Example 6]
As shown in Table 1, the blending amount of the isocyanate-based cross-linking agent (trade name "Coronate HL", manufactured by Nippon Polyurethane Co., Ltd.) was 20.0 parts by weight in terms of solid content, and the low molecular weight polyol (trade name "Sannics GP250 ", number average molecular weight Mn = 250, manufactured by Sanyo Chemical Industries Co., Ltd.) was changed to 5.0 parts by weight in terms of solid content. A pressure-sensitive adhesive layer (6) formed from was produced to obtain a surface protective film (6). Table 2 shows the results.

[Example 7]
As shown in Table 1, the blending amount of the isocyanate-based cross-linking agent (trade name “Coronate HL”, manufactured by Nippon Polyurethane Co., Ltd.) was changed to 4.5 parts by weight in terms of solid content, and the low molecular weight polyol (trade name “San Nix GP250", number average molecular weight Mn = 250, manufactured by Sanyo Chemical Industries Co., Ltd.), a low molecular weight polyol (trade name "Sannics GP600", number average molecular weight Mn = 600, manufactured by Sanyo Chemical Industries Co., Ltd.) is solidified. A pressure-sensitive adhesive layer (7) formed from the pressure-sensitive adhesive composition (7) was prepared in the same manner as in Example 4 except that 1.0 part by weight was used in terms of minutes, and a surface protective film (7) was obtained. rice field. Table 2 shows the results.

[Example 8]
As shown in Table 1, the compounding amount of the isocyanate-based cross-linking agent (trade name "Coronate HL", manufactured by Nippon Polyurethane Co., Ltd.) was 7.3 parts by weight in terms of solid content, and the low molecular weight polyol (trade name "Sannics GP600 ", number average molecular weight Mn = 600, manufactured by Sanyo Chemical Industries Co., Ltd.) was changed to 3.0 parts by weight in terms of solid content. A pressure-sensitive adhesive layer (8) formed from was produced to obtain a surface protective film (8). Table 2 shows the results.

[Example 9]
As shown in Table 1, the blending amount of the isocyanate-based cross-linking agent (trade name "Coronate HL", manufactured by Nippon Polyurethane Co., Ltd.) was 10.0 parts by weight in terms of solid content, and the low molecular weight polyol (trade name "Sannics GP600 ", number average molecular weight Mn = 600, manufactured by Sanyo Chemical Industries Co., Ltd.) was changed to 5.0 parts by weight in terms of solid content. A pressure-sensitive adhesive layer (9) formed from was produced to obtain a surface protective film (9). Table 2 shows the results.

[Example 10]
As shown in Table 1, the blending amount of the isocyanate-based cross-linking agent (trade name “Coronate HL”, manufactured by Nippon Polyurethane Co., Ltd.) was changed to 4.0 parts by weight in terms of solid content, and the low molecular weight polyol (trade name “San Nix GP250", number average molecular weight Mn = 250, manufactured by Sanyo Chemical Industries Co., Ltd.), a low molecular weight polyol (trade name "Sannics GP1000", number average molecular weight Mn = 1000, manufactured by Sanyo Chemical Industries Co., Ltd.) is solidified. A pressure-sensitive adhesive layer (10) formed from the pressure-sensitive adhesive composition (10) was prepared in the same manner as in Example 4 except that 1.0 part by weight was used in terms of minutes, and a surface protective film (10) was obtained. rice field. Table 2 shows the results.

[Example 11]
As shown in Table 1, the blending amount of the isocyanate-based cross-linking agent (trade name "Coronate HL", manufactured by Nippon Polyurethane Co., Ltd.) was 5.6 parts by weight in terms of solid content, and the low molecular weight polyol (trade name "Sannics GP1000 ", number average molecular weight Mn = 1000, manufactured by Sanyo Chemical Industries Co., Ltd.) was changed to 3.0 parts by weight in terms of solid content. A pressure-sensitive adhesive layer (11) formed from was produced to obtain a surface protective film (11). Table 2 shows the results.

[Example 12]
As shown in Table 1, the compounding amount of the isocyanate-based cross-linking agent (trade name “Coronate HL”, manufactured by Nippon Polyurethane Co., Ltd.) was 7.3 parts by weight in terms of solid content, and the low molecular weight polyol (trade name “Sannics GP1000 ", number average molecular weight Mn = 1000, manufactured by Sanyo Chemical Industries Co., Ltd.) was changed to 5.0 parts by weight in terms of solid content. A pressure-sensitive adhesive layer (12) formed from was produced to obtain a surface protective film (12). Table 2 shows the results.

[Example 13]
As shown in Table 1, the blending amount of the isocyanate-based cross-linking agent (trade name "Coronate HL", manufactured by Nippon Polyurethane Co., Ltd.) was 16.0 parts by weight in terms of solid content, and the low molecular weight polyol (trade name "Sannics GP250 ", number average molecular weight Mn = 250, manufactured by Sanyo Chemical Industries Co., Ltd.) was changed to 1.5 parts by weight in terms of solid content, and a fluorine-containing polymer (trade name "F-571", manufactured by DIC Corporation) Instead of using hydroxyl group-containing silicone (trade name “X-22-4015, manufactured by Shin-Etsu Chemical Co., Ltd.”) 0.05 parts by weight in terms of solid content, the same procedure as in Example 4 was performed, and the pressure-sensitive adhesive composition A pressure-sensitive adhesive layer (13) formed from the product (13) was produced to obtain a surface protective film (13). Table 2 shows the results.

[Comparative Example 1]
As shown in Table 1, the blending amount of the isocyanate-based cross-linking agent (trade name “Coronate HL”, manufactured by Nippon Polyurethane Co., Ltd.) was changed to 3.2 parts by weight in terms of solid content, and the low molecular weight polyol (trade name “San Nix GP250", number average molecular weight Mn = 250, manufactured by Sanyo Chemical Industries, Ltd.) was not used, and the fluorine-containing polymer (trade name "F-571", manufactured by DIC Corporation) was not used. 4, a pressure-sensitive adhesive layer (C1) formed from the pressure-sensitive adhesive composition (C1) was produced to obtain a surface protective film (C1). Table 2 shows the results.

[Comparative Example 2]
As shown in Table 1, the same procedure as in Comparative Example 1 was performed except that the amount of the isocyanate-based cross-linking agent (trade name "Coronate HL", manufactured by Nippon Polyurethane Co., Ltd.) was changed to 4.6 parts by weight in terms of solid content. A pressure-sensitive adhesive layer (C2) formed from the pressure-sensitive adhesive composition (C2) was produced to obtain a surface protective film (C2). Table 2 shows the results.

[Comparative Example 3]
As shown in Table 1, the procedure was carried out in the same manner as in Comparative Example 2, except that 0.05 parts by weight of a fluorine-containing polymer (trade name “F-571”, manufactured by DIC Corporation) in terms of solid content was further blended. A pressure-sensitive adhesive layer (C3) formed from the agent composition (C3) was produced to obtain a surface protective film (C3). Table 2 shows the results.

[Comparative Example 4]
As shown in Table 1, the adhesive composition was prepared in the same manner as in Comparative Example 2, except that 5 parts by weight of fatty acid ester (trade name “Salacos 816” manufactured by Nisshin OilliO Co., Ltd.) in terms of solid content was further blended. A pressure-sensitive adhesive layer (C4) formed from the product (C4) was produced to obtain a surface protective film (C4). Table 2 shows the results.

[Comparative Example 5]
As shown in Table 1, the blending amount of the isocyanate-based cross-linking agent (trade name “Coronate HL”, manufactured by Nippon Polyurethane Co., Ltd.) was changed to 9.3 parts by weight in terms of solid content, and the fluorine-containing polymer (trade name “F -571", manufactured by DIC Corporation) is further blended with 0.01 part by weight in terms of solid content, and fatty acid ester (trade name "Salacos 816", manufactured by Nisshin OilliO Co., Ltd.) is added in terms of 1 part by weight in terms of solid content. A pressure-sensitive adhesive layer (C5) formed from the pressure-sensitive adhesive composition (C5) was produced in the same manner as in Comparative Example 1, except that the composition was further blended, to obtain a surface protective film (C5). Table 2 shows the results.

[Comparative Example 6]
As shown in Table 1, the same procedure as in Comparative Example 5 was performed except that the amount of the isocyanate cross-linking agent (trade name "Coronate HL", manufactured by Nippon Polyurethane Co., Ltd.) was changed to 12.4 parts by weight in terms of solid content. A pressure-sensitive adhesive layer (C6) formed from the pressure-sensitive adhesive composition (C6) was produced to obtain a surface protective film (C6). Table 2 shows the results.

[Comparative Example 7]
As shown in Table 1, instead of the urethane prepolymer solution A obtained in Production Example 1, a commercially available urethane prepolymer solution (trade name “Siavine SH-109” manufactured by Toyochem Co., Ltd.) was used in terms of polymer solid content of 100. Using parts by weight, instead of the isocyanate cross-linking agent (trade name "Coronate HL", manufactured by Nippon Polyurethane Co., Ltd.), an isocyanate cross-linking agent (trade name "Coronate HX", manufactured by Nippon Polyurethane Co., Ltd.) is converted to solid content. The procedure was carried out in the same manner as in Comparative Example 1, except that 3.6 parts by weight was used and 1.0 parts by weight of a fluorine-containing polymer (trade name "F-571", manufactured by DIC Corporation) was added in terms of solid content. , a pressure-sensitive adhesive layer (C7) formed from the pressure-sensitive adhesive composition (C7) was produced to obtain a surface protective film (C7). Table 2 shows the results.

[Examples 14 to 26]
For each of the surface protective films (1) to (13) obtained in Examples 1 to 13, the separator was peeled off, and the pressure-sensitive adhesive layer side was coated with a polarizing plate (manufactured by Nitto Denko Corporation, trade name "TEG1465DUHC") to obtain an optical member to which the surface protection film was attached.

[Examples 27 to 39]
For each of the surface protective films (1) to (13) obtained in Examples 1 to 13, the separator was peeled off, and the pressure-sensitive adhesive layer side was coated with a conductive film (manufactured by Nitto Denko Corporation, trade name: "Elecrysta V270L-TFMP") to obtain an electronic member with a surface protective film attached.

The surface protective film of the present invention can be used for any suitable application. Preferably, the surface protective film of the present invention is preferably used in the fields of optical members and electronic members.

1 Base layer 2 Adhesive layer 10 Surface protection film

Claims (8)

A surface protection film having an adhesive layer,
The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive composition, and the pressure-sensitive adhesive composition comprises a urethane prepolymer, a polyfunctional isocyanate compound, a low molecular weight polyol, a silicone additive and/or a fluorine-based containing additives and heat stabilizers,
The adhesive comprises a urethane resin formed from a composition containing the urethane prepolymer and the polyfunctional isocyanate compound,
The low molecular weight polyol is a polyol having a number average molecular weight Mn of 1400 or less,
The content of the low-molecular-weight polyol in the adhesive composition is 0.01 to 50 parts by weight with respect to 100 parts by weight of the base polymer,
The content of the silicone-based additive and/or the fluorine-based additive in the pressure-sensitive adhesive composition is 0 as the total amount of the silicone-based additive and the fluorine-based additive with respect to 100 parts by weight of the base polymer. .001 to 50 parts by weight,
After aging the surface protective film at room temperature for 7 days, the pressure-sensitive adhesive layer is attached to a glass plate and allowed to stand at a temperature of 23 ° C. for 30 minutes, and then the surface protective film is peeled off from the glass plate at a temperature of 23 ° C. The peel force A is 0.005 N/25 mm to 0.50 N/25 mm when the peel force when peeled at an angle of 180 degrees and a peel speed of 300 mm / min is defined as peel force A,
After aging the surface protective film at room temperature for 7 days, the pressure-sensitive adhesive layer is attached to a glass plate and allowed to stand at a temperature of 100°C for 2 days, and then the surface protective film is peeled off from the glass plate at a temperature of 23°C. When the peel force when peeled at an angle of 180 degrees and a peel speed of 300 mm / min is peel force B, the peel force increase rate P calculated by (peeling force B / peeling force A) × 100 is 400% or less. and
The pressure-sensitive adhesive layer has a storage modulus at −70° C. of 5.0×10 ⁸ Pa to 1.0×10 ¹⁰ Pa,
The pressure-sensitive adhesive layer has a storage modulus at 23° C. of 7.0×10 ⁵ Pa to 1.0×10 ⁷ Pa,
The pressure-sensitive adhesive layer has a storage modulus at 100° C. of 7.0×10 ⁵ Pa to 5.0×10 ⁶ Pa.
surface protection film. After aging the surface protective film for 7 days at room temperature, the adhesive layer is laminated to a glass plate and left at 23 ° C. for 7 days, and then the surface protective film is peeled from the glass plate at a temperature of 23 ° C. When peel force C is the peel force when peeled at 180 degrees at a peel speed of 300 mm / min, the rate of increase in peel force over time calculated by (peeling force C / peeling force A) × 100 is 160% or less. The surface protection film according to claim 1, wherein 3. The surface protective film according to claim 1, which has a residual adhesion rate to a glass plate of 50% or more at 23[deg.]C. 4. The surface protective film according to any one of claims 1 to 3, wherein the adhesive composition contains a fatty acid ester. 5. The surface protection film according to any one of claims 1 to 4, wherein the silicone additive is at least one compound selected from a siloxane bond-containing compound, a hydroxyl group-containing silicone compound, and a crosslinkable functional group-containing silicone compound. . 6. The surface protective film according to any one of claims 1 to 5, wherein the fluorine-based additive is at least one selected from a fluorine-containing compound, a hydroxyl group-containing fluorine-based compound, and a crosslinkable functional group-containing fluorine-based compound. An optical member to which the surface protective film according to any one of claims 1 to 6 is adhered. An electronic member to which the surface protective film according to any one of claims 1 to 6 is adhered.

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