JPH10176148A - Surface protective film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare a surface protective film which has suitable tackiness against various adherends, can be easily separated at the time of peeling, and does not contaminate the surface of the adherend. SOLUTION: This surface protective film comprises a pressuresensitive adhesive layer laminated on and integrated with a substrate of a polyolefin resin. In this case, the pressuresensitive adhesive layer comprises: 80 to 99wt.% block copolymer represented by the formula A-B-A and block copolymer represented by the formula A-B (wherein A represents a styrene polymer block, B represents a butadiene polymer block, an isoprene polymer block, or an olefin polymer block obtd. by hydrogenating a butadiene polymer block or an isoprene polymer block); and 20 to 1wt.% hydrogenation product of a random copolymer of styrene with a diene hydrocarbon.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is to temporarily adhere to the surface of an adherend such as a synthetic resin plate, a metal plate, a decorative plywood, a coated coated steel plate, various nameplates, etc., in order to prevent dust from adhering to the plate surface and to prevent scratching. The present invention relates to a surface protective film used for:

[0002]

2. Description of the Related Art When processing or transporting a synthetic resin plate, a metal plate, a decorative plywood, various nameplates, etc., dirt adheres to the plate surface.
In order to prevent scratches, it is common practice to temporarily attach a surface protection film to the plate surface.

As such a surface protective film, a film obtained by laminating and integrating an adhesive layer on one surface of a base material made of a thermoplastic resin or paper is used. In use, the adhesive is temporarily attached to the surface of the plate, and when it is no longer needed, it is peeled off and removed. In such a case, it is required that the material is easily peeled off and that the surface of the adherend is not contaminated.

To satisfy such demands, Japanese Patent Publication No. Sho 58-30911 discloses a specific copolymer rubber alone or a tackifier resin of not more than 30 parts by weight based on 100 parts by weight of the rubber. Under certain circumstances, a pressure-sensitive adhesive having a specific adhesive strength is disclosed.
No. 3975 discloses an adhesive containing 100 parts by weight of a specific copolymer and 0 to 80 parts by weight of a tackifying resin.

However, both pressure-sensitive adhesives are inferior in the ability to hold a constant load, and when a surface protective film using the pressure-sensitive adhesive is used on a surface of a plate having a large surface roughness such as a polyester-coated steel plate or an acrylic-coated steel plate, As a result, there was a problem that the material was peeled off from the surface of the plate, resulting in a so-called partially floating state.

[0006]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and has an appropriate adhesiveness to an adherend, particularly an adherend having a large surface roughness regardless of the passage of time. Another object of the present invention is to provide a surface protective film which can be easily peeled off and does not contaminate the adherend surface.

[0007]

Means for Solving the Problems The surface protective film of the present invention is a surface protective film obtained by laminating and integrating an adhesive layer on a substrate made of a polyolefin resin. A block copolymer represented by -BA and a block copolymer represented by the general formula AB (where A is a styrene-based polymer block, B is a butadiene polymer block, an isoprene polymer block or butadiene) An olefin-based polymer block obtained by hydrogenating a polymer block or an isoprene polymer block.) 80 to 99% by weight and a hydrogenated product of a random copolymer of styrene and a diene-based hydrocarbon 20 to 1% by weight %.

[0008] The polyolefin resin constituting the base material is not particularly limited as long as it has been conventionally widely used as a base material for a surface protective film. Examples thereof include low-density polyethylene, medium-density polyethylene, and high-density polyethylene. , Linear low-density polyethylene, ethylene-α-olefin copolymer, propylene-α-olefin copolymer,
Ethylene-ethyl (meth) acrylate copolymer, ethylene-methyl (meth) acrylate copolymer, ethylene-n-butyl (meth) acrylate copolymer, ethylene-vinyl acetate copolymer, polypropylene and the like,
These may be used alone or in combination. In addition,
The α-olefin is not particularly limited as long as it can be copolymerized with ethylene. For example, propylene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-
Butene, 1-pentene, 1-heptene and the like.

The polyolefin resin constituting the base material includes fillers and lubricants such as talc, stearamide, calcium stearate and the like; inorganic hollow fibers such as glass balloons and silica balloons as long as the physical properties thereof are not impaired. Reinforcing agents such as particles; polymer microspheres, antioxidants,
An ultraviolet absorber, an ultraviolet stabilizer and the like may be added.

Next, the pressure-sensitive adhesive laminated on the base material will be described. General formula A which is one of the components of the pressure-sensitive adhesive
-B-A block copolymer represented by general formula AB
(Where A is a styrene polymer block, B is a butadiene polymer block, an isoprene polymer block, or an olefin polymer obtained by hydrogenating a butadiene polymer block or an isoprene polymer block.) (Hereinafter referred to as "styrene-based thermoplastic elastomer"), the weight average molecular weight of the styrene-based polymer block (A) is preferably 4,000 to 40,000, and more preferably 8,000.
To 20,000, and those having a glass transition temperature of 20 ° C. or higher are preferred.

The weight average molecular weight of a butadiene polymer block, an isoprene polymer block or an olefin polymer block (B) obtained by hydrogenating a butadiene polymer block or an isoprene polymer block is 5%.
0000 to 450,000, preferably 100,00
The glass transition temperature is more preferably 0 to 300,000, and the glass transition temperature is preferably -20 ° C or lower.

The weight ratio of the component A to the component B in the styrene thermoplastic elastomer is as follows: component A: component B =
2 to 50: 98 to 50 is preferable, and A component: B component = 5
To 30:95 to 70 is more preferred. The general formula AB
Of a block copolymer represented by -A (hereinafter referred to as "ABA copolymer") and a block copolymer represented by general formula AB (referred to as AB copolymer) The weight ratio is A-
BA copolymer: AB copolymer = 20 to 100: 80
To 0, more preferably ABA copolymer: AB copolymer = 50 to 100: 50 to 0. Note that, as can be seen from the above, the AB copolymer may be added as needed.

Furthermore, the pressure-sensitive adhesive layer contains a hydrogenated product of a random copolymer of styrene and a diene-based hydrocarbon. When the content of the styrene component in the hydrogenated product of the random copolymer of styrene and diene hydrocarbon is too high, the hardness becomes too high and the adhesiveness is lowered. Since it is not suitable, 1 to 40% by weight is preferable, and 5 to 30% by weight is more preferable.

The mixing ratio of the styrene-based thermoplastic elastomer in the pressure-sensitive adhesive layer to the hydrogenated product of a random copolymer of styrene and a diene-based hydrocarbon (hereinafter referred to as “hydrogenated SD random copolymer”) If the hydrogenated SD random copolymer is too large, the adhesive strength is too strong to be suitable for practical use. Conversely, if it is small, when used on the surface of an adherend having a large surface roughness, the surface protective film will become aging over time. Is separated from the surface of the adherend and becomes a so-called partially floating state, so that the styrene-based thermoplastic elastomer: SD random copolymer hydrogenated product is limited to 80 to 99:20 to 1 by weight%.

The pressure-sensitive adhesive layer may further comprise an aliphatic petroleum resin or an alicyclic petroleum resin in addition to the ethylene thermoplastic elastomer and the hydrogenated SD random copolymer as long as the physical properties are not impaired. , alicyclic hydrogenated petroleum resins, aromatic petroleum resins, C ₅ petroleum resins, terpene resins, terpene phenol resins, coumarone-indene resin, may be a tackifier such as rosin resin is added, these May be used alone or in combination.

If the amount of the tackifier is too large, the cohesive force of the pressure-sensitive adhesive layer is reduced, adhesive residue may be generated, and the adherend may be contaminated. It is preferably at most 120 parts by weight, more preferably at most 100 parts by weight, particularly preferably at most 60 parts by weight.

In addition, an α-methylstyrene resin may be added in order to give the pressure-sensitive adhesive an appropriate release property required for the surface protective film. If the amount of the α-methylstyrene resin is too large, the adhesive strength of the pressure-sensitive adhesive is reduced and the adhesive may not function as a surface protective film. Therefore, the amount is preferably 120 parts by weight or less based on 100 parts by weight of the styrene-based thermoplastic elastomer.

In addition, in addition to the above, additives such as an antioxidant may be added to the pressure-sensitive adhesive layer as long as the physical properties are not impaired.

Finally, a method for producing the surface protective film of the present invention will be described. The method for producing the surface protective film of the present invention is not particularly limited, a general-purpose method is used, for example,
The polyolefin-based resin constituting the base material is supplied to one extruder and melt-kneaded, while the styrene-based thermoplastic elastomer and the SD random copolymer hydrogenated product constituting the pressure-sensitive adhesive layer are added if necessary. A method of feeding and imparting an imparting agent or α-methylstyrene resin to another extruder, melt-kneading them, co-extruding them, laminating and integrating a base material and an adhesive layer, a solvent on a pre-manufactured base material, Examples include a method of applying the dissolved pressure-sensitive adhesive, and a method of extruding and laminating the pressure-sensitive adhesive on a previously manufactured base material.

In the surface protective film obtained by the above-described co-extrusion method, the interface between the base material and the pressure-sensitive adhesive layer is firmly integrated not only by chemical bonding by polarity but also by physical bonding by an anchor effect. Therefore, the base material and the pressure-sensitive adhesive layer do not easily peel off, and in combination with the excellent peelability of the pressure-sensitive adhesive itself, the resulting surface protective film has excellent peelability, so that it is manufactured by co-extrusion. The method is preferred.

In the above production process, the thickness of the substrate in the obtained surface protective film is 20 to 100 μm.
m, the thickness of the pressure-sensitive adhesive layer is preferably adjusted to 3 to 50 μm.

[0022]

【Example】

Example 1 Low-density polyethylene (trade name: Mirason 12 manufactured by Mitsui Petrochemical Co., Ltd.) was supplied to one extruder and melt-kneaded as a resin constituting a base material, while styrene was used as a resin constituting an adhesive layer. -90 parts by weight of a hydrogenated product of a butadiene-styrene block copolymer (trade name: Septon 2043, manufactured by Kuraray Co., Ltd.), and a hydrogenated product of a random copolymer of styrene and a diene-based hydrocarbon (trade name, manufactured by Nippon Synthetic Rubber Co., Ltd.) : Dinalon 1321P, styrene component content: 10% by weight), 10 parts by weight, alicyclic petroleum resin (trade name: Alcon P100, manufactured by Arakawa Chemical Co., Ltd.) and 40 parts by weight of antioxidant (Ciba Geigy, product name: Irganox 1010) ) 0.5 parts by weight was supplied to another extruder, melt-kneaded, and co-extruded to form a film having a thickness of 1 μm on a 50 μm-thick polyethylene substrate. A surface protective film in which a 0 μm pressure-sensitive adhesive layer was laminated and integrated was obtained.

The initial adhesive strength of the polycarbonate sheet, the initial adhesive strength of the acrylic-coated steel sheet, and the adhesive strength with time of the acrylic-coated steel sheet of the obtained surface protective film were measured by the following methods, and the results are shown in Table 1. In addition, even at the time of measuring the time-dependent adhesive force of the acrylic coated steel sheet, the surface protection film was stuck well without peeling off from the steel sheet surface, and was not in a so-called partially floating state.

(Initial Adhesive Strength of Polycarbonate Plate) The obtained surface protective film was cut into a width of 25 mm and a thickness of 2 mm.
Is adhered to the surface of a polycarbonate plate (trade name: Iupilon NF-2000, manufactured by Mitsubishi Gas Chemical Company) at a speed of 300 mm / min using a 2 kg pressure roller and left for 30 minutes, in accordance with JIS Z0237-8. The 180 ° peel adhesive strength at a pulling speed of 300 mm / min was measured, and this was defined as the initial adhesive strength. The above operations were all performed under a constant temperature and humidity condition of 23 ° C. and a humidity of 65%.

(Initial Adhesive Strength of Acrylic Painted Steel Sheet) The obtained surface protection film was cut into a width of 25 mm, and a 2 mm thick acrylic coated steel sheet (surface gloss: 22%) was coated on a surface of a 2 kg pressure roller using a 2 kg pressure roller. 300mm / min
JIS Z
The 180 ° peel adhesive strength at a pulling speed of 300 mm / min was measured according to 0237-8, and this was defined as the initial adhesive strength. The above operations were all performed under a constant temperature and humidity condition of 23 ° C. and a humidity of 65%.

(Acrylic Painted Steel Sheet Temporal Adhesion) The obtained surface protective film was cut into a width of 25 mm, and a 2 mm-thick acrylic-coated steel sheet (surface gloss: 22%) was pressed using a 2 kg pressure roller on the surface. 300mm / min
At a speed of This is fed into a gear oven,
After heating at 70 ° C for 30 minutes, temperature is 23 ° C and humidity is 65%
What was left for 1 day under the above conditions was measured for 180 ° peel adhesive force at a pulling speed of 300 mm / min in accordance with JIS Z0237-8, and this was regarded as the adhesive force over time.

Comparative Example 1 A hydrogenated styrene-butadiene-styrene block copolymer (trade name: SEPTON 204, manufactured by Kuraray Co., Ltd.) was used as the resin constituting the pressure-sensitive adhesive layer.
3) 100 parts by weight of alicyclic petroleum resin (Arakawa Chemical Co., Ltd.)
Trade name: Alcon P100) 40 parts by weight and antioxidant (trade name: Irganox 1010, manufactured by Ciba-Geigy)
A surface protective film was obtained in the same manner as in Example 1 except that 0.5 part by weight was used.

The initial adhesive strength of the polycarbonate sheet, the initial adhesive strength of the acrylic coated steel sheet, and the temporal adhesive strength of the acrylic coated steel sheet of the obtained surface protective film were measured in the same manner as in Example 1, and the results are shown in Table 1. . In addition, when measuring the time-dependent adhesive force of the acrylic coated steel sheet, the surface protection film was partially peeled off from the steel sheet and was in a so-called partially floating state, and could not be measured.

[0029]

[Table 1]

[0030]

Since the surface protective film of the present invention has the above-mentioned constitution, it has excellent initial adhesiveness to all adherends and maintains its excellent adhesive strength during use. It is easy to peel off after use, and has an excellent effect of not leaving glue residue and not contaminating the adherend surface.

In particular, the surface protective film of the present invention has an excellent initial adhesive strength even on an adherend having a painted surface and a large surface roughness, and the adhesiveness is maintained even after a lapse of time after temporary attachment. Maintains force and does not peel off from the adherend surface during use.

Claims (1)

[Claims] 1. A surface protective film in which a pressure-sensitive adhesive layer is laminated and integrated on a base material made of a polyolefin resin, wherein the pressure-sensitive adhesive layer is a block copolymer represented by the general formula ABA And a block copolymer represented by the general formula AB (where A is a styrene-based polymer block, B is a butadiene polymer block, an isoprene polymer block, or a hydrogenated butadiene polymer block or isoprene polymer block. 80 to 99% by weight and a hydrogenated product of a random copolymer of styrene and a diene-based hydrocarbon, 20 to 99% by weight.
A surface protective film containing 1% by weight.