JP2713519B2 - Surface protection film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a pressure-sensitive adhesive composition,
More specifically, the obtained adhesive tape or sheet or surface protective film exhibits good re-peelability in a wound body, has good rewindability, that is, developability without using a release agent, and has a long term And a pressure-sensitive adhesive composition which maintains a good peeling force over a long period of time and has a lower adhesive strength at high speed peeling than at low speed peeling. The present invention also relates to a pressure-sensitive adhesive tape or sheet or a surface protective film using the above-mentioned pressure-sensitive adhesive composition.

[0002]

2. Description of the Related Art ABA (wherein A is a styrene polymer block, B is a butadiene polymer block, an isoprene polymer block or a polymer block obtained by hydrogenating them). Is known to be a thermoplastic elastomer suitable for an adhesive (for example, a handbook of
"Handbook of Pressure Sensitive Adhesive Technol"
ogy "Second Edition, 1989).

Japanese Patent Publication No. 58-13594 discloses a general formula ABA (where A is a styrene-based polymer block, B is a butadiene polymer block, an isoprene polymer block or a hydrogenated product thereof). A pressure-sensitive hot-melt pressure-sensitive adhesive composition containing a required amount of a block copolymer, a tackifying resin, and a developing oil represented by the following formulas: The product is described as a pressure-sensitive adhesive which has remarkably excellent heat resistance and good electrical properties.

Japanese Patent Laid-Open No. 1-129085 discloses that
A is represented by the general formula ABA (where A represents a styrene-based polymer block, B represents a butadiene polymer block, an isoprene polymer block, or a polymer block obtained by hydrogenating them). A surface protective film using a pressure-sensitive adhesive comprising a block copolymer, a tackifying resin, and a polyethyleneimine having a higher alkyl group introduced therein is disclosed.

[0005]

By the way, as a product form such as an adhesive tape, a wound body in which these are wound up in a coil shape with the adhesive layer inside is generally used. In such a wound body, the pressure-sensitive adhesive layer of the outer substrate and the back surface of the inner substrate are in close contact with a relatively strong adhesive force. Difficult to peel off.

Therefore, when the pressure-sensitive adhesive tape is rewound from the wound body, the pressure-sensitive adhesive can be easily rewound without causing migration of the pressure-sensitive adhesive to the back side of the inner substrate, blocking, and cracking of the substrate. Usually, a so-called release treatment is performed on the back surface of the base material. Conventionally, as the release treatment, a method of applying a release agent on the back surface of the base material in advance is often performed.

However, it is extremely difficult for the release agent to have the contradictory properties of firmly adhering to the back surface of the base material and appropriately releasing the pressure-sensitive adhesive layer. For this reason, it is necessary to take measures such as using a special release agent, applying an undercoat on the back surface of the base material, or performing a corona discharge treatment on the back surface of the base material. As the release agent, a linear alkyl group-containing polymer (for example, polyvinyl ester allyl carbamate), a silicone-based polymer, a perfluoro-based polymer, and the like are used.

However, in the method using the release agent as described above, the material cost is increased by the amount of the release agent, and a complicated release agent application step is required. However, even in the obtained pressure-sensitive adhesive tape roll, there was a quality problem that the release agent migrated to the pressure-sensitive adhesive layer and caused a decrease in the adhesive strength.

The pressure-sensitive adhesive tape roll using the pressure-sensitive adhesive composition described in Japanese Patent Publication No. 58-13594 and Japanese Patent Application Laid-Open No. 1-129085 also has the above-mentioned problems. For example, when a pressure-sensitive adhesive composition disclosed in Japanese Patent Publication No. 58-13594 is melt-coated on kraft paper to form a kraft paper pressure-sensitive adhesive tape roll, polyethylene is preliminarily laminated on the surface opposite to the surface of the kraft paper coated with the pressure-sensitive adhesive. Then, it is necessary to apply a release agent.

The present invention has been made in view of the above-mentioned circumstances, and has as its object to exhibit good removability in the obtained pressure-sensitive adhesive tape roll without using a release agent. It has good unwinding property, that is, developing property, maintains good developing force and re-peeling property over a long period of time, and is more adhesive than high-speed peeling at a high speed peeling speed of 20 to 30 m / min in actual use. An object of the present invention is to provide a pressure-sensitive adhesive composition having a reduced force and a pressure-sensitive adhesive tape or sheet or a surface protective film using the pressure-sensitive adhesive composition.

[0011]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in order to overcome the problems of the prior art, and as a result, a required amount of the general formula ABA as a pressure-sensitive adhesive composition has been obtained.
Or a block copolymer represented by AB (where A is a styrene-based polymer block, B is a butadiene polymer block, an isoprene polymer block, or a polymer obtained by hydrogenating the same. Block means), a required amount of tackifying resin, and a resin containing a required amount of polyolefin,
Demonstrates good re-peelability, has good unwinding properties without using a release agent, maintains good peel force over a long period of time, and has lower adhesive strength at high speed peeling than at low speed peeling It has been found that an adhesive tape or sheet or a surface protective film can be obtained.

The present invention has been completed based on such findings. That is, the pressure-sensitive adhesive composition according to the present invention comprises a block copolymer represented by the general formula ABA or AB (where A is a styrene-based polymer block, and B is a butadiene polymer). 100 parts by weight, 10 to 200 parts by weight of a tackifying resin, 10 parts by weight of polyolefin, and 10 parts by weight of a polyolefin 10
To 200 parts by weight.

[0013] The pressure-sensitive adhesive composition according to the present invention further comprises a polyethyleneimine having a higher alkyl group introduced therein of 0.01 to 0.01.
It may contain 5 parts by weight. The pressure-sensitive adhesive composition according to the present invention may further contain 5 to 100 parts by weight of a liquid rubber.

[0014] The pressure-sensitive adhesive composition according to the invention is used as the adhesive layer of the adhesive tape or sheet. The base material of the pressure-sensitive adhesive tape or sheet is not particularly limited, and examples thereof include kraft paper, cloth, and a thermoplastic resin film. When paper such as kraft paper is used, it is preferable to laminate a polyolefin such as polyethylene or polypropylene in advance on the surface opposite to the surface coated with the adhesive, that is, on the back surface.

The pressure-sensitive adhesive composition according to the present invention further comprises:
Temporarily adhere to the surface of synthetic resin plate, decorative plywood, metal plate, etc.
Surface protective film used to prevent adhesion and damage
It is used as an adhesive layer of the system. As a substrate of such a surface protection film, a film made of a polyolefin such as polyethylene and polypropylene and a mixture thereof is employed. The film may be unstretched or uniaxially or multiaxially stretched.

Hereinafter, each component of the pressure-sensitive adhesive composition according to the present invention and a method for producing a pressure-sensitive adhesive tape or sheet or a surface protective film will be described in detail. a) In the block copolymer represented by the general formula ABA or AB, one of the constituent components A, that is, the styrene polymer block, has an average molecular weight of 12,000.
About 0 to 100,000 and glass transition temperature 2
Those at 0 ° C. or higher are preferred.

The other component B, ie, a butadiene polymer block, an isoprene polymer block or a polymer block obtained by hydrogenating them, has an average molecular weight of about 10,000 to 300,000. And a glass transition temperature of −20 ° C. or less.

The preferred weight ratio of component A to component B is A / B = 5/95 to 50/50, more preferably 10/90 to 30/70. The weight ratio of the block copolymer represented by the general formula ABA to the block copolymer represented by the general formula AB is ABA / AB = 1.
00/0 to 20/80, more preferably 100/0 to 5
0/50.

B) The tackifying resin is represented by the general formula A-
A resin that is selectively compatible with the component B of the block copolymer represented by BA and the block copolymer represented by general formula AB is used. As such a resin, for example, an aliphatic hydrocarbon resin, a terpene resin, a coumarone-indene resin, an aromatic hydrocarbon resin, a rosin resin, and the like are suitably used.

The compounding amount of the tackifying resin is represented by the general formula AB
-A or block copolymer 100 represented by AB
It is in the range of 10 to 200 parts by weight based on parts by weight. The reason is that if the amount of the tackifying resin is less than 10 parts by weight, no tackiness is exhibited, and if it exceeds 200 parts by weight, cohesive strength is lost. The compounding amount of the tackifying resin is
Preferably 20 to 150 parts by weight, more preferably 30 to 150 parts by weight.
100 parts by weight.

C) The polyolefin is not particularly restricted but includes low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, ethylene-α olefin copolymer, ethylene-ethyl acrylate copolymer, ethylene -Vinyl acetate copolymer, ethylene-methyl methacrylate copolymer, ethylene-n-butyl acrylate copolymer, (crystalline) polypropylene or a mixture thereof.

The polyolefin preferably has a low molecular weight component, and specifically, the low molecular weight component extracted by boiling point distillation with n-pentane is preferably less than 1.0% by weight. If the low-molecular-weight component exceeds 1.0% by weight, the low-molecular-weight component adversely affects the adhesive properties according to a change in temperature or a change with time, and lowers the adhesive strength.

The compounding amount of the polyolefin is represented by the general formula AB
-A or block copolymer 100 represented by AB
It is in the range of 10 to 200 parts by weight based on parts by weight. The reason is that if the blending amount of the polyolefin is less than 10 parts by weight, good rewindability cannot be obtained, and if it exceeds 200 parts by weight, tackiness is lost. The blending amount of the polyolefin is preferably 15 to 1 with respect to 100 parts by weight of the block copolymer represented by the general formula ABA or AB.
80 parts by weight, more preferably 20 to 150 parts by weight.

D) Polyethyleneimine into which a higher alkyl group has been introduced is an optional additional component that is optionally contained. Examples of this component include an average molecular weight of 1,000.
The higher alkyl group is preferably introduced in an amount of 0.5 to 1.0 equivalent to the imine group of polyethyleneimine, more preferably 0.7 to 20,000.
1.0 equivalent. As the higher alkyl group, an alkyl group having 12 or more carbon atoms is generally preferable, and an octadecyl group is particularly preferable. In order to introduce a higher alkyl group into polyethyleneimine, for example, a method is employed in which an excess higher alkylisocyanate is added to polyethyleneimine to carry out an addition reaction.

The amount of the polyethyleneimine having a higher alkyl group introduced therein is 0.00.0 parts by weight based on 100 parts by weight of the block copolymer represented by the general formula ABA or AB.
It is in the range of 1 to 5 parts by weight. The reason is that if the blending amount of polyethyleneimine is less than 0.01 part by weight, it is not possible to suppress the increase in tackiness with the passage of time, and if it exceeds 5 parts by weight, a large amount of this bleeds out on the surface of the adhesive layer. This is because the adherend is contaminated. The blending amount of polyethyleneimine having a higher alkyl group introduced therein is preferably 0.1.
It is 1 to 2 parts by weight, more preferably 0.2 to 1.2 parts by weight.

E) Liquid rubber is an optional additional component that is optionally included. Examples of the liquid rubber include polybutene, polyisobutylene, and (liquid) polyisoprene, and those having a weight average molecular weight of about 500 to 50,000 are preferable. Further, those having no functional group in the molecule are preferable. Particularly, when a double bond is present in the molecule, heat resistance is inferior.

The compounding amount of the liquid rubber is in the range of 5 to 100 parts by weight based on 100 parts by weight of the block copolymer represented by the general formula ABA or AB. The reason is,
If the amount of the liquid rubber is less than 5 parts by weight, wettability cannot be obtained, and if it exceeds 100 parts by weight, cohesive strength is lost.

F) A stabilizer such as an antioxidant may be added to the pressure-sensitive adhesive composition according to the present invention, if necessary. For example, the antioxidant “Irganox 1010” (Ciba.
Geigy) is effective against thermal degradation.

G) The method for producing a pressure-sensitive adhesive tape or sheet or a surface protective film using the pressure-sensitive adhesive composition of the present invention is not particularly limited, and a coating method, an extrusion laminating method, and a co-extrusion method are appropriately employed. When the material is made of a thermoplastic resin such as a polyolefin resin, it is preferable to use a co-extrusion method.

[0030]

The pressure-sensitive adhesive tape or sheet or the surface protective film using the pressure-sensitive adhesive composition according to the present invention has a smaller thickness than the pressure-sensitive adhesive composition without the addition of polyolefin.
Since the storage modulus of the pressure-sensitive adhesive composition at ordinary temperature increases and the wettability between the composition and the substrate decreases, the adhesive force between the pressure-sensitive adhesive composition and the back surface of the substrate decreases, and the adhesive tape or the like is rewound or developed. Becomes easier. In addition, the adhesive strength at the time of high-speed peeling is lower than that at the time of low-speed peeling.

The pressure-sensitive adhesive tape or sheet or the surface protective film using the pressure-sensitive adhesive composition of the present invention has a greater effect on the adhesion between the composition and the base material than when a developing oil, low molecular weight polyethylene or the like is added. Since the wettability is reduced, the rewinding property of the adhesive tape or the like is also improved in this respect.

Further, when the pressure-sensitive adhesive composition contains a polyethyleneimine having a higher alkyl group introduced, the polyethyleneimine bleeds out moderately to the surface of the pressure-sensitive adhesive and has a physicochemical affinity with the adherend. It is thought that this moderately suppresses the increase in tackiness over time. The pressure-sensitive adhesive composition also has good melt extrusion characteristics, and is suitable for co-extrusion with a thermoplastic resin such as polyolefin.

Further, when the pressure-sensitive adhesive composition contains a liquid rubber, the liquid rubber has a high molecular weight, so that the surface of the adherend is not contaminated as compared with the case where the developing oil is added. .

[0034]

EXAMPLES Next, in order to specifically explain the present invention, examples of the present invention and comparative examples for comparison with the present invention will be given, and further, a performance test on the obtained adhesive tape or surface protective film. The result is shown.

Hereinafter, “parts” means “parts by weight”. Example 1 Styrene-butadiene-styrene block copolymer ("Califlex TR-1107" manufactured by Shell Chemical Company) 10
0 parts, 100 parts of a tackifier resin ("Escolets 4401" manufactured by Tonex), 80 parts of low-density polyethylene ("Mirason 12" manufactured by Mitsui Petrochemical Industries, Ltd.), and an antioxidant ("Yoshinox 425" manufactured by Yoshitomi Pharmaceutical Co., Ltd.) One part of the composition was mixed well at 180 ° C. under a nitrogen atmosphere and supplied to a coating machine with a gear pump.

One side of kraft paper having a thickness of 90 μm is previously coated with polyethylene (“Mirason 16” manufactured by Mitsui Petrochemical Industries, Ltd.).
On the surface opposite to the polyethylene surface of the substrate extruded and laminated so as to have a thickness of 16 μm, the pressure-sensitive adhesive composition was heated and melt-coated with a coating machine so as to have a thickness of 40 μm,
An adhesive tape was obtained.

Example 2 In place of the styrene-butadiene-styrene block copolymer, a styrene-isoprene-styrene block copolymer ("Califlex TR-110" manufactured by Shell Chemical Company) was used.
2 "), except that adhesive tape was obtained in the same manner as in Example 1.

Example 3 Hydrogenated product of styrene-isoprene-styrene block copolymer ("Septon 2063" manufactured by Kuraray Co., Ltd.) 100
Part, tackifying resin (“Clearon P” manufactured by Yasuhara Yushi Kogyo Co., Ltd.)
-115 ") 100 parts, linear low density polyethylene (Mitsubishi Yuka Co., Ltd." UF840 ") 40 parts, antioxidant (Ciba
An adhesive tape was obtained in the same manner as in Example 1 except that a composition consisting of 1 part of "Irganox 1010" manufactured by Geigy Corporation was used.

Example 4 Hydrogenated product of styrene-butadiene-styrene block copolymer ("TUFTEC H1052" manufactured by Asahi Kasei Corporation)
100 parts, 100 parts of tackifying resin ("Alcon P-100" manufactured by Arakawa Chemical Industries, Ltd.), 30 parts of low-density polyethylene ("Mirason 12" manufactured by Mitsui Petrochemical Industries, Ltd.), antioxidant ("Yoshitomi Pharmaceutical" Yoshinox 425 ") In the same manner as in Example 1 except that a composition consisting of 1 part was used,
An adhesive tape was obtained.

Example 5 Hydrogenated product of styrene-butadiene-styrene block copolymer ("TUFTEC H1052" manufactured by Asahi Kasei Corporation)
100 parts, 50 parts of tackifying resin ("Alcon P-100" manufactured by Arakawa Chemical Industry Co., Ltd.), 30 parts of low density polyethylene ("Mirason 12" manufactured by Mitsui Petrochemical Industry Co., Ltd.), antioxidant (manufactured by Yoshitomi Pharmaceutical Co., Ltd.) Yoshinox 425 ") and a low-density polyethylene (" Mirason 12 "manufactured by Mitsui Petrochemical Industries, Ltd.) formed by co-extrusion with 1 part of the composition such that the former has a thickness of 15 μm and the latter has a thickness of 100 μm. Then, an adhesive tape was obtained.

Example 6 The pressure-sensitive adhesive composition of Example 1 was further added with polyethyleneimine in which a higher alkyl group was introduced [octadecyl group was added to polyethyleneimine (average molecular weight: 2,000) at an imine group of 0.1%.
9 equivalents] was obtained in the same manner as in Example 1 except that 1 part was added.

Example 7 An adhesive tape was obtained in the same manner as in Example 2 except that 1 part of the same polyethyleneimine as in Example 6 was further added to the adhesive composition of Example 2.

Example 8 An adhesive tape was obtained in the same manner as in Example 3 except that 1 part of the same polyethyleneimine as in Example 6 was further added to the adhesive composition of Example 3.

Example 9 An adhesive tape was obtained in the same manner as in Example 4, except that 1 part of the same polyethyleneimine as in Example 6 was further added to the adhesive composition of Example 4.

Example 10 An adhesive tape was obtained in the same manner as in Example 5 except that 1 part of the same polyethyleneimine as in Example 6 was further added to the adhesive composition of Example 5.

Example 11 Hydrogenated product of styrene-butadiene-styrene block copolymer ("Clayton G1657" manufactured by Shell Chemical Company)
100 parts, 30 parts of a tackifier resin ("Escolets 5300" manufactured by Tonex Corporation), 100 parts of low-density polyethylene ("Mirason 16" manufactured by Mitsui Petrochemical Industries, Ltd.), 2 parts of the same polyethylene imine as in Example 6, antioxidant 1 part of agent (“Irganox 1010” manufactured by Ciba-Geigy) and an ultraviolet absorber (“Tinuvin 326” manufactured by Ciba-Geigy)
Extrusion molding of a composition consisting of 0.5 part and low density polyethylene (Mirason 16 manufactured by Mitsui Petrochemical Industry Co., Ltd.) by a two-layer coextrusion method with the former having a thickness of 8 μm and the latter having a thickness of 50 μm. Thus, a surface protective film was obtained.

Example 12 Hydrogenated product of styrene-butadiene-styrene block copolymer ("Clayton G1657" manufactured by Shell Chemical Company)
100 parts, 40 parts of a tackifier resin ("Escolets 5300" manufactured by Tonex Corporation), 70 parts of low-density polyethylene ("Mirason 16" manufactured by Mitsui Petrochemical Industries, Ltd.), Example 6
2 parts of polyethyleneimine and antioxidant (Ciba.
1 part of Geigy “Irganox 1010”), UV absorber (“Tinuvin 326” manufactured by Ciba-Geigy)
Example 1 except that a composition consisting of 0.5 parts was used.
In the same manner as in Example 1, a surface protection film was obtained.

Example 13 Hydrogenated product of styrene-butadiene-styrene block copolymer ("Clayton G1657" manufactured by Shell Chemical Company)
100 parts, 60 parts of tackifying resin ("Escolets 5300" manufactured by Tonex), 20 parts of low density polyethylene ("Mirason 16" manufactured by Mitsui Petrochemical Industries), Example 6
2 parts of polyethyleneimine and antioxidant (Ciba.
1 part of Geigy “Irganox 1010”), ultraviolet absorber (Ciba Geigy “Tinuvin 326”)
A surface protective film was obtained in the same manner as in Example 11 except that a composition consisting of 5 parts was used.

Example 14 Hydrogenated product of styrene-isoprene-styrene block copolymer ("Septon 2063" manufactured by Kuraray Co., Ltd.) 100
Part, tackifying resin (“Clearon P” manufactured by Yasuhara Yushi Kogyo Co., Ltd.)
-125 ") 20 parts, low-density polyethylene (" Mirason 16 "manufactured by Mitsui Petrochemical Industries, Ltd.) 120 parts, the same polyethylene imine as in Example 6, 2 parts, antioxidant (" Irganox 1010 "manufactured by Ciba-Geigy) 1 part, UV absorber (“Tinuvin 326” manufactured by Ciba-Geigy) 0.5
Part, light stabilizer ("LA-63" manufactured by Adeka Argus)
Example 1 except that a composition consisting of 0.5 parts was used.
In the same manner as in Example 1, a surface protection film was obtained.

Example 15 Hydrogenated product of styrene-butadiene-styrene block copolymer ("Clayton G1652" manufactured by Shell Chemical Company)
100 parts, 50 parts of a tackifier resin ("Escorez 5300" manufactured by Tonex), 50 parts of medium density polyethylene ("Neozex 3510F" manufactured by Mitsui Petrochemical Industries, Ltd.),
2 parts of polyethyleneimine and antioxidant (“Irganox 1010” manufactured by Ciba-Geigy) as in Example 6
Part, UV absorber (“Tinuvin 32” manufactured by Ciba-Geigy)
6)) A composition consisting of 0.5 part and polypropylene (“Noblen FL664” manufactured by Mitsui Toatsu Chemicals, Inc.), with the former having a thickness of 8 μm and the latter having a thickness of 50 μm.
Extrusion molding was performed by a layer coextrusion method to obtain a surface protective film.

Example 16 A surface protective film was obtained in the same manner as in Example 15 except that a linear low-density polyethylene ("UF840" manufactured by Mitsubishi Yuka Co., Ltd.) was used instead of polypropylene.

Example 17 A surface protective film was obtained in the same manner as in Example 15 except that high-density polyethylene ("HY430" manufactured by Mitsubishi Yuka Co., Ltd.) was used instead of polypropylene.

Example 18 Instead of polypropylene, a mixture of 100 parts of high-density polyethylene ("HY430" manufactured by Mitsubishi Yuka Co., Ltd.) and 100 parts of low-density polyethylene ("LK30" manufactured by Mitsubishi Yuka Co., Ltd.) was used. A surface protective film was obtained in the same manner as in Example 15 except for the above.

Example 19 Hydrogenated product of styrene-butadiene-styrene block copolymer ("Clayton G1657" manufactured by Shell Chemical Company)
100 parts, 50 parts of a tackifier resin ("Escolets 5300" manufactured by Tonex Corporation), 100 parts of low-density polyethylene ("Mirason 16" manufactured by Mitsui Petrochemical Industries, Ltd.), 2 parts of the same polyethylene imine as in Example 6, polybutene ( "Idemitsu Polybutene 300H" manufactured by Idemitsu Petrochemical Co., Ltd.
00), 1 part of an antioxidant (“Irganox 1010” manufactured by Ciba-Geigy), 0.5 part of an ultraviolet absorber (“Tinuvin 327” manufactured by Ciba-Geigy), and a low-density polyethylene ( Mitsui Petrochemical Industry Co., Ltd. “Mirason 12”), the former is 10 μm in thickness, and the latter is 5 μm in thickness.
Extrusion molding was performed by a two-layer coextrusion method so as to have a thickness of 0 μm to obtain a surface protective film.

Example 20 Hydrogenated product of styrene-butadiene-styrene block copolymer ("Clayton G1657" manufactured by Shell Chemical Company)
100 parts, 40 parts of a tackifier resin ("Escolets 5300" manufactured by Tonex Corporation), 70 parts of low-density polyethylene ("Mirason 16" manufactured by Mitsui Petrochemical Industries, Ltd.), Example 6
2 parts polyethyleneimine, liquid polyisoprene
(Kuraray “Kuraprene LIR-290” molecular weight 2
(5,000) 1 part of an antioxidant ("Irganox 1010" manufactured by Ciba-Geigy) and 0.5 part of an ultraviolet absorber ("Tinuvin 327" manufactured by Ciba-Geigy) were used. Except for the above, the same as in Example 19,
A surface protective film was obtained.

Example 21 Hydrogenated product of styrene-isoprene-styrene block copolymer (“Septon 2063” manufactured by Kuraray Co., Ltd.) 100
Part, tackifying resin (“Clearon P” manufactured by Yasuhara Yushi Kogyo Co., Ltd.)
-125 ") 20 parts, low-density polyethylene (" Mirason 16 "manufactured by Mitsui Petrochemical Industry Co., Ltd.) 120 parts, polyethyleneimine 2 parts same as in Example 6, liquid polyisoprene (Kuraray Co., Ltd." Claprene LIR-30 "molecular weight) 29,00
0) 40 parts, 1 part of antioxidant (“Irganox 1010” manufactured by Ciba-Geigy), 0.5 part of ultraviolet absorber (“Tinuvin 327” manufactured by Ciba-Geigy), light stabilizer (Adeka Argus) LA-63 ") A surface protective film was obtained in the same manner as in Example 19 except that a composition consisting of 0.5 parts was used.

Comparative Example 1 A naphthenic oil (SUN) was used in place of low density polyethylene.
An adhesive tape was obtained in the same manner as in Example 1 except that 50 parts of "Sansen Oil" manufactured by OCO Company was used.

Comparative Example 2 A naphthenic oil (SUN) was used in place of low density polyethylene.
An adhesive tape was obtained in the same manner as in Example 2 except that 50 parts of "Sansen Oil" manufactured by OCO Company was used.

Comparative Example 3 An adhesive tape was obtained in the same manner as in Example 1 except that 1 part of the same polyethyleneimine as in Example 6 was further added to the adhesive composition of Comparative Example 2.

Comparative Example 4 Hydrogenated product of styrene-butadiene-styrene block copolymer ("Clayton G1657" manufactured by Shell Chemical Company)
100 parts, 20 parts of a tackifier resin ("Escolets 5300" manufactured by Tonex), 2 parts of the same polyethyleneimine as in Example 6, 1 part of an antioxidant ("Irganox 1010" manufactured by Ciba-Geigy), and an ultraviolet absorber (Ciba Geigy's “Tinuvin 326”) 0.5 part of a composition and low-density polyethylene (“Milason 16” manufactured by Mitsui Petrochemical Industry Co., Ltd.) were used.
Extrusion was performed by coextrusion so as to have a thickness of 0 μm to obtain a surface protective film.

Comparative Example 5 Tackifying resin ("ESCOLETS 53" manufactured by Tonex Corporation)
00 ") was changed to 50 parts, and a surface protective film was obtained in the same manner as in Comparative Example 4.

Comparative Example 6 Hydrogenated product of styrene-butadiene-styrene block copolymer ("Clayton G1657" manufactured by Shell Chemical Company)
100 parts, 20 parts of a tackifier resin ("Escolets 5300" manufactured by Tonex), 2 parts of the same polyethyleneimine as in Example 6, 1 part of an antioxidant ("Irganox 1010" manufactured by Ciba-Geigy), and an ultraviolet absorber (Ciba Geigy's “Tinuvin 327”) 0.5 part of a composition and low-density polyethylene (Mitsui Petrochemical Co., Ltd. “Mirason 16”), the former having a thickness of 10 μm and the latter having a thickness of 50 μm. Thus, a surface protective film was obtained by extrusion molding by a coextrusion method.

Comparative Example 7 Hydrogenated product of styrene-isoprene-styrene block copolymer (“Septon 2063” manufactured by Kuraray Co., Ltd.) 100
Part, tackifying resin (“Clearon P” manufactured by Yasuhara Yushi Kogyo Co., Ltd.)
-125 ") 30 parts, 2 parts of the same polyethyleneimine as in Example 6, 1 part of antioxidant (" Irganox 1010 "manufactured by Ciba-Geigy), and 0 ultraviolet absorber (" Tinuvin 327 "manufactured by Ciba-Geigy) 0 A surface protective film was obtained in the same manner as in Comparative Example 6, except that a composition consisting of 0.5 parts was used.

Performance test The pressure-sensitive adhesive tape or surface protective film obtained in each of the above Examples and Comparative Examples was used as a roll, and the SP pressure, holding power, and unfolding force during rewinding of each roll were measured by the following methods. did. Table 1 summarizes the measurement results. SP adhesive strength: a method according to JIS-Z0237-8 (peeling speed 300 mm / min) Holding force: a method according to JIS-Z0237-11, a developing force: a method according to JIS-Z0237-10,

[0065]

[Table 1]

As described above, the adhesive tape or the surface protective film roll obtained in Examples 1 to 21 does not break when the tape or film is peeled off from the roll, and exhibits an appropriate developing force. It turns out that it has moderate initial adhesive strength. On the other hand, in Comparative Examples 4 to 7, it was found that the developing force immediately after production was 10 times or more that of Examples 11 to 18, and in the pressure-sensitive adhesive tape roll obtained in Comparative Examples 1 to 7, the developing force was increased after lapse of time. Is too high to peel off. In addition, in the pressure-sensitive adhesive tapes or surface protective films obtained in Examples 6 to 21, it can be seen that excessive increase in tackiness with time is almost completely prevented.

Next, for Examples 11 and 12 and Comparative Example 4, the SP adhesive strength after curing for 30 days at 30 ° C. under a pressure of 50 ton / m ^{2 was} measured at a low speed (300 mm / min) and a high speed (3 mm).
(0 m / min). Table 2 summarizes the measurement results.

[0068]

[Table 2]

As described above, in the pressure-sensitive adhesive tape or surface protective film roll obtained in Examples 11 and 12, the adhesive force at low speed is slightly higher, but at a high speed, it is moderate. On the other hand, in the pressure-sensitive adhesive tape roll obtained in Comparative Example 4, on the other hand, it is found that although it is moderate at low speed, it becomes high at high speed.

At the time of actual use, the pressure-sensitive adhesive tape or the surface protective film roll is moved at a high speed (20 to 3) from the adherend.
0 m / min), the examples are processing, storage,
It exhibits desirable properties as a surface protective film that is difficult to peel off during transportation and easy to peel off after use.

Example 22 Hydrogenated product of styrene-butadiene-styrene block copolymer ("Clayton G1657" manufactured by Shell Chemical Company)
100 parts, 100 parts of tackifying resin ("Alcon P-100" manufactured by Arakawa Chemical Industry Co., Ltd.), low density polyethylene ("LK-30" manufactured by Mitsubishi Yuka Co., Ltd.) is washed by boiling with n-hexane to remove low molecular weight components. 80 parts, an antioxidant (Ciba.
A composition consisting of 1 part of "Irganox 1010" manufactured by Geigy Co., Ltd. and a low-density polyethylene ("Mirason 16" manufactured by Mitsui Petrochemical Industries, Ltd.) were subjected to T-die molding so that the former had a thickness of 20 μm and the latter had a thickness of 60 μm. Extrusion molding was performed by a two-layer coextrusion method to obtain a surface protective film.

Example 23 The procedure of Example 22 was repeated except that a hydrogenated styrene-butadiene-styrene block copolymer was replaced with a styrene-butadiene block copolymer ("Tuffrene A" manufactured by Asahi Kasei Kogyo Co., Ltd.). Thus, a surface protective film was obtained.

Example 24 Instead of the hydrogenated styrene-butadiene-styrene block copolymer, a styrene-isoprene block copolymer ("Califlex TR110" manufactured by Shell Chemical Co., Ltd.) was used.
A surface protective film was obtained in the same manner as in Example 22 except that 2)) was used.

Example 25 Instead of low-density polyethylene, an ethylene-α-olefin copolymer ("Tuffmer A-40" manufactured by Mitsui Petrochemical Industries, Ltd.)
85 "was washed with boiling n-hexane to remove low molecular weight components, and the extraction amount with respect to n-pentane was adjusted to 0.5% by weight.) Surface protection was carried out in the same manner as in Example 22 except that 30 parts were used. A film was obtained.

Comparative Example 8 A surface protective film was obtained in the same manner as in Example 22 except that no polyolefin was used in the pressure-sensitive adhesive composition.

Comparative Example 9 A surface protective film was obtained in the same manner as in Example 23 except that no polyolefin was used in the pressure-sensitive adhesive composition.

The surface protective films obtained in Examples 22 to 25 and Comparative Examples 8 to 9 were rewound immediately after being formed into a roll (development force), and left at room temperature (23 ° C.) for 12 hours after production. SP adhesive strength after production and 40 after production
C. After standing for 7 days, the SP adhesion was measured. Note that these measurement methods are described in Example 1 above.
To 21 and the same method as the measurement method for the surface protective films obtained in Comparative Examples 1 to 7.

Table 3 summarizes these results.

[0079]

[Table 3]

In the above Examples 22 to 25, the extraction amount of the low molecular weight component relative to n-pentane was less than 1.0% by weight, but the extraction amount of the low molecular weight component relative to n-pentane was less than 1.0% by weight. When using a polyolefin exceeding 1.0% by weight, for example, (a) n-
A surface protection film obtained in the same manner as in Example 22 except that low-density polyethylene (“LK-30” manufactured by Mitsubishi Yuka Co., Ltd., extraction amount to n-pentane: 2.1% by weight) not washed with pentane was used. , (B) Low density polyethylene not boiled and washed with n-pentane (“LK
-30 ", 2.1% by weight based on n-pentane)
Surface protective film obtained in the same manner as in Example 23, except that (c) a low-density polyethylene not boiled and washed with n-pentane (“LK-30” manufactured by Mitsubishi Yuka, n-
A surface protection film obtained in the same manner as in Example 24 except that an extraction amount relative to pentane of 2.1% by weight) was used;
(D) Ethylene-α-olefin copolymer not boiled and washed with n-pentane (“Tuffmer A- manufactured by Mitsui Petrochemical Co., Ltd.)
4085 ", a surface protective film obtained in the same manner as in Example 25 except that an elution amount to n-pentane of 1.5% by weight was used. ) Are (a) 390, (b) 350,
(C) 340 and (d) 720, but after 7 days at 40 ° C., (a) 95, (b) 80,
It can be seen that (c) is extremely reduced to 65 and (d) 120, and it is preferable that the elution amount of a low molecular weight component relative to n-pentane is 1.0% by weight or less.

[0081]

Since the pressure-sensitive adhesive composition of the present invention is constituted as described above, a pressure-sensitive adhesive tape or sheet or a roll of a surface protective film obtained by using the pressure-sensitive adhesive composition exhibits good removability. It has good unwinding property, that is, developing property without using a release agent, and maintains good developing force and re-peeling property over a long period of time, and has lower adhesive strength at high speed peeling than at low speed peeling. .

Further, those containing polyethyleneimine having a higher alkyl group introduced therein can suppress the adhesive strength from excessively increasing with time.

Claims (2)

(57) [Claims] 1. A block copolymer represented by the general formula ABA or AB (where A is a styrene-based polymer block, B is a butadiene polymer block, and an isoprene polymer) Pressure-sensitive adhesive comprising 100 parts by weight, 10 to 200 parts by weight of tackifying resin, and 10 to 200 parts by weight of polyolefin resin.
Layer on one side of a polyolefin substrate film
Surface protective film that is layered. 2. The pressure-sensitive adhesive further contains 0.01 to 5 parts by weight of polyethyleneimine having a higher alkyl group introduced therein.
Surface protective film according to claim 1 wherein formed by.