JPH10183077A - Surface protective film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare a surface protective film which has suitable tackiness against an adherend, does not cause an increase in the strength of adhesion to the adherend upon heating or pressing after application to the surface of the adherend, can be easily peeled off, does not contaminate the surface of the adherend, and has suitable tackiness against an adherend having high surface roughness. SOLUTION: This surface protective film comprises a pressure-sensitive adhesive layer laminated onto and integrated with a substrate layer formed of a thermoplastic resin. The pressure-sensitive adhesive layer comprises: 100 pts.wt. hydrogenation product of a random copolymer of 1 to 40wt.% styrene with 99 to 60wt.% diene hydrocarbon; 5 to 120 pts.wt. tackifier; 5 to 120 pts.wt. α-methylstyrene resin; and/or 0.05 to 5 pts.wt. fatty acid amide.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a surface protective film, and more particularly, to a synthetic resin plate, a metal plate, a decorative plywood,
Temporarily attached to the surface of adherends such as coated painted steel plates and various nameplates,
The present invention relates to a surface protective film used for preventing dust from adhering to and scratching a plate surface.

[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.

[0003] As such a surface protective film, a film obtained by laminating and integrating an adhesive layer on one surface of a base material layer 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 requirements, Japanese Patent Application Laid-Open No. 7-241960 discloses that 60% by weight of a hydrogenated random copolymer consisting of 1 to 50% by weight of styrene and 99 to 50% by weight of a diene hydrocarbon. A surface protective film using an adhesive having a composition of not less than 40% by weight and not more than 40% by weight of a polyolefin is disclosed.

[0005] However, when the above-mentioned pressure-sensitive adhesive is applied to the surface of the adherend, if heat or pressure is applied thereto, the adhesive force to the adherend is remarkably increased, and adhesive residue is generated when peeling. There has been a problem that the surface of the adherend is contaminated, and the adherend having a large surface roughness does not exhibit appropriate tackiness and does not adhere to the surface of the adherend.

[0006]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems, and has a proper adhesiveness to an adherend.
Adhesive strength to the adherend does not increase even when heated or pressed after being adhered to the adherend surface, it can be easily peeled off, does not contaminate the adherend surface, and has a large surface roughness Another object of the present invention is to provide a surface protective film exhibiting appropriate adhesiveness to the 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 a base material layer made of a thermoplastic resin and an adhesive layer. Styrene 1 to 40% by weight and diene hydrocarbon 9
100 parts by weight of a hydrogenated random copolymer consisting of 9 to 60% by weight, 5 to 120 parts by weight of a tackifier, 5 to 120 parts by weight of an α-methylstyrene resin and / or 0.05 to 5 parts by weight of a fatty acid amide Parts are contained.

The hydrogenated product of the random copolymer comprising styrene and diene hydrocarbon contained in the pressure-sensitive adhesive layer has a styrene content of 1 to 40% by weight and a diene hydrocarbon content of 99 to 60. If it is% by weight, it is not particularly limited, but those having a weight average molecular weight of 100,000 to 600,000, more preferably about 200,000 to 500,000 are used. Specifically, the product name “Dynalon 132” manufactured by Nippon Synthetic Rubber Co., Ltd.
0P "," Dynalon 1321P "," Dynalon 19 "
10P "and the like are available.

The reason that the styrene content is limited to 1 to 40% by weight is that if the styrene content is too high, the adhesion to the adherend is insufficient,
If the amount is too small, the cohesive force as an adhesive is reduced, adhesive residue is generated at the time of peeling, and the adherend is contaminated.
３０30% by weight.

On the other hand, the diene hydrocarbon content is 99%.
The reason why the amount is limited to 60% by weight is that if the amount is too large, the cohesive force as an adhesive is reduced, adhesive residue is generated at the time of peeling, and the adherend is contaminated, and if the amount is small, the adhesion to the adherend is insufficient. And preferably 95 to 70% by weight.

The tackifier is not particularly limited as long as it can be used for a surface protective film. Examples thereof include aliphatic petroleum resins, alicyclic petroleum resins, and alicyclic hydrogenated petroleum resins. , aromatic petroleum resins, C ₅ petroleum resins, terpene resins, terpene phenol resins, coumarone-indene resins, rosin resins, and the like. these may be used in combination be used alone.

When the amount of the tackifier is large, the cohesive force of the pressure-sensitive adhesive layer is reduced and adhesive residue may be generated to contaminate the adherend, and when the amount is small, the effect of adding the tackifier is reduced. Since it may not be exhibited, it is limited to 5 to 120 parts by weight based on 100 parts by weight of a hydrogenated product of a random copolymer composed of styrene and a diene-based hydrocarbon;
The amount is preferably 00 parts by weight, more preferably 10 to 60 parts by weight.

Further, the pressure-sensitive adhesive layer may have an α in order to provide the pressure-sensitive adhesive with an appropriate release property required for a surface protective film.
-Methylstyrene resin and / or fatty acid amide are added.

When the above-mentioned α-methylstyrene resin is added, the bonding strength between the pressure-sensitive adhesive layer and the surface of the adherend is reduced, and the adhesion to the adherend after aging does not increase. And the appropriate adhesiveness required in the above.

If the amount of the α-methylstyrene resin is too large, the adhesive strength of the pressure-sensitive adhesive is reduced and the film may not function as a surface protective film. If the amount is too small, the effect of adding the α-methylstyrene resin is not exhibited. Therefore, the amount is limited to 5 to 120 parts by weight based on 100 parts by weight of the hydrogenated product of the random copolymer composed of styrene and diene hydrocarbon.

On the other hand, when the above fatty acid amide is added, it is possible to impart excellent releasability after a lapse of time while maintaining an appropriate initial adhesive strength in the adhesive layer. The fatty acid amide is not particularly limited as long as it can be used for a surface protective film. For example, ethylene bisstearic acid amide, stearic acid amide, methylene bisstearic acid amide, oleic acid amide, lauric acid amide And the like, and these may be used alone or in combination.

If the amount of the fatty acid amide is too large, the initial adhesive strength of the pressure-sensitive adhesive layer may be reduced to make it impossible to use it as a surface protective film.
Since the effect of adding the fatty acid amide may not be obtained, 0.05 to 100 parts by weight of the hydrogenated product of the random copolymer composed of styrene and diene hydrocarbon is used.
Limited to 5 parts by weight.

Further, polyethyleneimine having a higher alkyl group grafted thereon may be added to the pressure-sensitive adhesive layer as long as the physical properties are not impaired, and the polyethyleneimine having the higher alkyl group grafted thereto may be added. In addition, it is possible to impart an appropriate initial adhesive force to the pressure-sensitive adhesive layer, and to suppress an increase in the adhesive force to the adherend after the lapse of time under pressure.

If the amount of the polyethyleneimine to which the higher alkyl group is grafted is too large, the initial adhesive strength of the pressure-sensitive adhesive layer may be reduced and the film may not be used as a surface protective film. Since the effect of the addition may not be obtained, the amount is preferably 0.05 to 5 parts by weight based on 100 parts by weight of a hydrogenated product of a random copolymer composed of styrene and a diene-based hydrocarbon.

Finally, a small amount of an antioxidant, a plasticizer, a filler, a colorant, etc. may be added to the pressure-sensitive adhesive layer as long as the physical properties are not impaired.

Next, the base material layer is made of a thermoplastic resin.
The thermoplastic resin is not particularly limited as long as it can be used as a substrate of the surface protective film, and examples thereof include polyolefin-based, polyester-based, and polyvinyl chloride-based resins. In consideration of the above, a polyolefin type is preferably used. Examples of the polyolefin resin include low-density polyethylene, medium-density polyethylene, 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, Examples thereof include polypropylene, and these may be used alone or in combination. 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.

Fillers and lubricants such as talc, stearamide, calcium stearate and the like; glass balloon,
Reinforcing agents such as inorganic hollow particles such as silica balloons; polymer microspheres, antioxidants, ultraviolet absorbers, ultraviolet stabilizers and the like may be added.

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, for example, a hydrogenated product of a base layer made of a thermoplastic resin and a random copolymer composed of styrene and a diene-based hydrocarbon, a tackifier, α- The base material layer and the pressure-sensitive adhesive layer are laminated and integrated by co-extruding a pressure-sensitive adhesive layer containing a methylstyrene resin and / or a fatty acid amide and, if necessary, a polyethyleneimine to which a higher alkyl group is grafted, to form a surface. Examples of the method include a method of manufacturing a protective film, a method of laminating the pressure-sensitive adhesive layer on the substrate layer by laminating after forming the substrate layer, and the like. In the former, a known method such as an inflation method or a T-die method is used, and in the latter, a dry lamination or a melt extrusion method or an extrusion coating method using a T-die can be used. It is preferable in terms of quality and economy. The thickness of both layers is
What is necessary is just to adjust suitably according to an application, and the base material layer usually has 2
The thickness is adjusted to 0 to 100 μm, and the pressure-sensitive adhesive layer is adjusted to 3 to 50 μm.

[0024]

【Example】

(Examples 1 to 10, Comparative Examples 1 to 5) Polyethylene constituting a base material layer (trade name: Mirason 1 manufactured by Mitsui Petrochemical Co., Ltd.)
2. Melt index at 190 ° C .: 3.0 g /
10 minutes) to one extruder and melt-kneaded, and as a resin constituting the pressure-sensitive adhesive layer, a hydrogenated product of a random copolymer composed of styrene and a diene-based hydrocarbon (1) (Nippon Synthetic Rubber Co., Ltd.) Product name: Dinalon 1321P, styrene content: 10% by weight, diene-based hydrocarbon: 90% by weight, melt index at 230 ° C .: 10 g / 1
0 minutes), a hydrogenated random copolymer (2) composed of styrene and a diene-based hydrocarbon (2) (manufactured by Nippon Synthetic Rubber Co., Ltd., trade name: Dinalon 1910P, styrene content: 30% by weight, diene-based hydrocarbon: 70) Wt%, melt index at 230 ° C .: 5.3 g / 10 min), tackifier (trade name: Escolets 530, manufactured by Tonex Corporation)
0), α-methylstyrene resin (trade name: Endex 155, manufactured by Hercules Co., Ltd.), ethylenebisstearic acid amide, polyethyleneimine having a higher alkyl group grafted (0.8 mol of octadecyl isocyanate)
The addition-reacted product, a number average molecular weight: 10,000) and an antioxidant (trade name: Irganox 1010, manufactured by Ciba Geigy) were supplied to another extruder in the composition shown in Table 1 or 2 and melt-kneaded. Then, the base material layer and the pressure-sensitive adhesive layer were coextruded with a thickness of 50 μm and a pressure-sensitive adhesive layer of 10 μm by an inflation method, and the base material layer and the pressure-sensitive adhesive layer were laminated and integrated to obtain a surface protective film.

The resulting surface protective film has an initial adhesive strength of a stainless steel plate, an adhesive force over time of a stainless steel plate (1), an initial adhesive force of an acrylic-coated steel plate, an adhesive force over time of an acrylic-coated steel plate (1) and (2), adherend contamination. And the interlayer strength was measured by the method shown below, and the result was shown in Table 1 or Table 2.

(Initial Adhesive Strength of Stainless Steel Plate) The obtained surface protective film was cut into a width of 25 mm, and 2 kg was applied to the surface of a stainless steel plate (SUS304, No. 280 polishing) having a thickness of 2 mm.
Was adhered at a speed of 300 mm / min using a pressure roller and left for 30 minutes, and the 180 ° peel adhesive force was measured according to JIS Z0237, and this was taken as the initial adhesive force. The above operations were all performed at 23 ° C and a humidity of 65%.
Under constant temperature and humidity conditions.

(Temperature Adhesive Strength of Stainless Steel Plate (1)) The obtained surface protective film was cut into a width of 25 mm and a thickness of 2 mm.
Was adhered to the surface of a stainless steel plate (SUS304, No. 280 polishing) at a speed of 300 mm / min using a 2 kg pressure roller. This is fed into a gear oven and
After heating at 3 ° C for 3 days, the temperature was further reduced to 23 ° C and humidity 65%.
What was left for 0 minutes was 1 according to JISZ0237.
The 80 ° peel adhesive strength was measured, and this was evaluated as the adhesive strength over time (1).
And

(Initial Adhesive Strength of Acrylic Painted Steel Plate) The initial adhesive force of the stainless steel plate was measured in the same manner as in the measurement of the initial adhesive force of the stainless steel plate except that it was adhered to an acrylic painted steel plate instead of being adhered to a stainless steel plate.

(Aging Coated Steel Sheet Temporal Adhesion (1)) An acrylic coated steel sheet (center line surface roughness (Ra): 1.3 μm) was used instead of the stainless steel sheet.
It measured using the same method as the measurement of the time-dependent adhesion (1) of the stainless steel plate.

(Acrylic Coated Steel Sheet Temporary Adhesive Strength (2)) The obtained surface protective film was cut into a width of 25 mm and had a thickness of 2 mm.
mm acrylic coated steel sheet (center line surface roughness (Ra):
1.3 μm) on the surface using a 2 kg pressure roller
It was stuck at a speed of 0 mm / min. This is 23 ° C, 50
After pressurizing for 7 days under the condition of 0 t / m ^2, the sample was further allowed to stand at a temperature of 23 ° C. and a humidity of 65% for 30 minutes according to JIS Z02.
The 180 ° peel adhesive force was measured according to 37, and this was defined as the adhesive force with time (2).

(Adherend Contamination) At the time of measuring adhesive strength, the presence or absence of contamination on the adherend surface after peeling was visually observed.

(Interlayer Strength) At the time of measuring the adhesive strength, the presence or absence of delamination at the interface between the base material layer and the pressure-sensitive adhesive layer of the surface protective film after peeling was visually observed.

[0033]

[Table 1]

[0034]

[Table 2]

[0035]

Since the surface protective film of the present invention is constituted as described above, it is placed in a heated environment or a pressurized environment while having a proper initial tackiness to the adherend. Even in such a case, adhesion promotion is suppressed, and peeling after use is easy, and the adherend is not contaminated. In addition, it has excellent initial adhesiveness even to an adherend having a large surface roughness, and also has an excellent effect of being easy to peel off after use.

When both layers are laminated and integrated by coextrusion, the two layers are firmly integrated together with a physical bond due to an anchor effect in addition to a chemical bond due to polarity. Even when peeling after use, the two layers are not separated. Therefore, in addition to the above-described excellent performance of the pressure-sensitive adhesive layer, the strong lamination and integration of the base material layer and the pressure-sensitive adhesive layer are combined, so that the adherend does not remain on the adherend even when peeled, thereby contaminating the adherend. There is an excellent effect that there is no.

Claims (2)

[Claims] 1. A surface protection film in which a base layer made of a thermoplastic resin and an adhesive layer are laminated and integrated,
The pressure-sensitive adhesive layer contains 100 parts by weight of a hydrogenated random copolymer consisting of 1 to 40% by weight of styrene and 99 to 60% by weight of a diene hydrocarbon, 5-120 parts by weight of a tackifier, α-methylstyrene. A surface protective film comprising 5 to 120 parts by weight of a resin and / or 0.05 to 5 parts by weight of a fatty acid amide. 2. The surface protective film according to claim 1, wherein the pressure-sensitive adhesive layer further contains 0.05 to 5 parts by weight of polyethyleneimine having a higher alkyl group grafted thereon.