JP2003327936A - Surface protective sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prepare a surface protective sheet having good adhesive strengths to various adherends, little increase in the adhesive strengths even when used in outdoor or preserved under high temperature conditions and easily peeled off from the adherends. <P>SOLUTION: This surface protective sheet is produced by coextruding a base substrate layer containing a polyolefin-based resin and a pressure sensitive adhesive layer containing a styrene-based thermoplastic elastomer. The styrene- based thermoplastic elastomer is a styrene-based block copolymer or its hydrogenated product having -40 to -25°C maximum temperature of tanδ by dynamic elasticity measurement at -6 to -10°C. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a surface protective sheet. The surface protection sheet of the present invention is, for example, a metal plate,
It is used for the purpose of attaching and protecting the surfaces of painted metal plates, aluminum sashes, resin plates, decorative steel plates, vinyl chloride laminated steel plates, glass plates, etc. when they are transported, processed or cured.

[0002]

2. Description of the Related Art As a characteristic required for a surface protection sheet,
It is required that the protective sheet does not float or peel off after being attached to the adherend, and that the adhesive layer does not remain on the adherend when peeling and removing. In particular, when the protective sheet attached to the adherend is placed under severe conditions such as high temperature or outdoor exposure until the protective sheet is peeled off, , More advanced things are required.

Conventionally, the adhesive layer of the surface protective sheet which has been generally used is made of natural rubber or modified natural rubber,
A natural rubber-based pressure-sensitive adhesive containing an appropriate amount of a tackifier is used. Such a surface protection sheet does not cause any particular problem when used indoors. However, since the natural rubber adhesive has an unsaturated double bond in its structure, UV irradiation causes molecular scission when exposed to the outside, and when the surface protective sheet is peeled off, it adheres to the adherend. The agent may remain. Therefore, a surface protection sheet having good weather resistance has been desired.

In order to solve the above problems, in the formation of the pressure-sensitive adhesive layer, the acrylic copolymer is crosslinked three-dimensionally with an isocyanate compound or a methylol compound to increase the cohesive strength to the extent that the acrylic copolymer does not lose its adhesiveness. Adhesives and synthetic rubber adhesives such as polyisobutylene have been proposed. However, since these pressure-sensitive adhesives are solvent-based, there are problems in terms of safety and hygiene of the surface protection sheet, pollution, and economical efficiency.

In recent years, in order to improve these problems, solvent-free adhesives have been demanded. As its effective means, a cohesive layer of a base material layer made of a polyolefin resin and an adhesive layer made of a thermoplastic elastomer is formed into a film,
A method for producing a surface protective sheet is being studied.

[0006] Generally, as a thermoplastic elastomer that can be coextruded, styrene / ethylene / butylene copolymer / styrene block polymer (SEBS), styrene / ethylene / propylene copolymer / styrene block polymer (SEPS) are used. Are known. These styrenic block copolymers have sufficient adhesiveness to the surface of an adherend such as a stainless plate or a resin plate having a relatively smooth adherend surface. On the other hand, these styrene block copolymers have poor adhesiveness to the adherend surface such as a polished stainless plate (hairline plate) or rough resin plate. Therefore, the pressure-sensitive adhesive layer of the protective sheet applied to the surface of the adherend such as the rough resin plate, the styrene-based block copolymer, by adding a large amount of tackifier or softener,
It is common to adjust the adhesive force of the adhesive layer (see, for example, Patent Document 1 and Patent Document 2).

However, the surface protective sheet having an adhesive layer containing a large amount of tackifier or the like adheres in a relatively short time when it is stored at a high temperature such as in a warehouse or a container in summer. Power will increase. Such an increase in adhesive strength has a problem such as peeling failure. Also,
When the surface protective sheet having increased adhesive strength is used for a smooth plate or the like, peeling failure occurs due to the influence of the tackifier or the like.

[0008]

[Patent Document 1] JP-A-5-194923 (second
page)

[0009]

[Patent Document 2] Japanese Unexamined Patent Publication No. 61-103975 (first)
page)

[0010]

DISCLOSURE OF THE INVENTION The present invention relates to a surface protective sheet in which a base material layer containing a polyolefin resin and an adhesive layer containing a styrene thermoplastic elastomer are formed by co-extrusion. Adhesiveness to the adherend is good, and even when it is used outdoors or stored under high temperature, the increase in the adhesive strength is small and the peelability when peeled from the adherend is good. It is intended to provide a surface protection sheet.

[0011]

As a result of intensive studies to solve the above problems, the present inventors have found the surface protection sheet shown below and completed the present invention.

That is, the present invention is a surface protection sheet in which a base material layer containing a polyolefin resin and an adhesive layer containing a styrene thermoplastic elastomer are formed by coextrusion, and the styrene thermoplastic elastomer is , The temperature at which the maximum tan δ value in dynamic viscoelasticity measurement in the measurement temperature range of −60 to 100 ° C. is −40 to −25.
A surface protection sheet, which is a styrene block copolymer having a temperature of 0 ° C. or a hydrogenated product thereof.

According to the present invention, the styrene-based thermoplastic elastomer used for forming the pressure-sensitive adhesive layer exhibits a maximum tan δ value in the above-mentioned dynamic viscoelasticity measurement at a higher temperature than that conventionally used. A block copolymer is used. Adhesion is increased by increasing the temperature at which the maximum tan δ value is reached. Also, by adjusting the temperature at which the maximum tan δ value is -40 to -25 ° C, appropriate wettability can be obtained. Therefore, the pressure-sensitive adhesive layer of the present invention has sufficient wettability and adhesiveness without adding a large amount of tackifier or the like. Therefore, the addition of a tackifier or the like can be suppressed to a small amount, and peeling failure and adhesive residue do not occur. The surface protective sheet of the present invention having such an adhesive layer,
By adjusting the physical properties of the pressure-sensitive adhesive layer, good adhesion is achieved even on a rough surface, and peeling failure does not occur even when applied to a flat surface.
In order to obtain good wettability and adhesiveness, the maximum temperature of the tan δ value in the dynamic viscoelasticity measurement is −40 ° C. to −3.
It is preferably 0 ° C. The dynamic viscoelasticity measurement is described in detail in Examples.

In the surface protective sheet, the adhesive layer 2
Storage elastic modulus at 0 ° C. is 1.0 × 10 ^{5 to} 8.0 ×
It is preferably 10 ⁵ Pa. From the viewpoint of adhesiveness to a rough surface, the storage elastic modulus at 20 ° C., which is a practical temperature range, is more preferably 1.5 × 10 ^{5 to} 7.5 × 10 ⁵ Pa, and further 2.0 × 10 5. ^{5 to} 7.0 x 10 ⁵ P
More preferably, it is a.

In the surface protective sheet, the polyolefin resin forming the base material layer has a density of 0.88 to 0.9.
It is preferably ³ g / cm ³ of linear low-density polyethylene. Various materials can be used for the polyolefin resin forming the base material layer, but from the viewpoint of flexibility of the base material, protection function against adherends, prevention of base material breakage during bending of metal plate, etc. Density polyethylene is preferred. In particular,
Those in the range of 0.895 to 0.92 g / cm ³ are preferable from the viewpoint of preventing floating during bending.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION In the surface protective sheet of the present invention, a base material layer containing a polyolefin resin and an adhesive layer containing a styrene thermoplastic elastomer are formed by coextrusion. In the styrene-based thermoplastic elastomer forming the adhesive layer, a styrene-based block having a maximum tan δ value in dynamic viscoelasticity measurement in the measurement temperature range of −60 to 100 ° C. of −40 to −25 ° C. A polymer or a hydrogenated product thereof is used.

Examples of the styrene-based block copolymer include styrene-based ABA type block copolymers (triblock copolymers) such as styrene / butadiene / styrene (SBS) and styrene / isoprene / styrene (SIS);
Styrene, butadiene, styrene, butadiene (SBS
B), a styrene-based ABAB type block copolymer (tetrablock copolymer) such as styrene / isoprene / styrene / isoprene (SISI); styrene / butadiene / styrene / butadiene / styrene (SBSBS), styrene / isoprene / styrene / Examples thereof include a styrene-based ABABA type block copolymer (pentablock copolymer) such as isoprene / styrene (SISIS), and a styrene-based block copolymer having more AB repeating units. As the styrene-based block copolymer, it is preferable to use a hydrogenated product obtained by hydrogenating an ethylenic double bond. For example, styrene / ethylene / butylene copolymer / styrene (SEBS), styrene / ethylene / propylene copolymer / styrene (SEPS), styrene / ethylene / butylene copolymer / styrene / ethylene / butylene copolymer (SEBSEB) Etc. These styrene block copolymers may be used alone or in combination of two or more.

The styrene block content in these styrenic block copolymers is not particularly limited, but those having a temperature at which the maximum tan δ value of the dynamic viscoelasticity measurement is within the above range are used. Usually, when the styrene block content is low, adhesive residue is likely to occur due to insufficient cohesive strength of the adhesive layer. On the other hand, when the styrene block content increases,
The adhesive layer formed by using the styrene block copolymer alone becomes hard, and good adhesiveness cannot be obtained on a rough surface. From this viewpoint, the styrene block content of the styrene block copolymer is preferably about 5 to 40% by weight. More preferably 7 to 30% by weight, especially 9 to
20 wt% is preferably used.

Among the above-mentioned styrene block copolymers, a triblock copolymer composed of styrene (A) and butadiene (B) having a repeating structure (ABA type, ABA type) or more
Hydrogenated products (SEBS, SEBSEB, SEBSE) of styrene block copolymers having B type, ABABA type, etc.
BS and the like) are preferred. In order to obtain good wettability and adhesiveness, the proportion of the butylene structure in the ethylene-butylene copolymer block in the hydrogenated product of the styrene block copolymer is 60% by weight or more, preferably 70% by weight or more. ,
Particularly, 75% by weight or more is preferable. When the butylene structure is 60% by weight or more, the wettability is good. In particular, it has good adhesiveness, and also adheres well to rough surfaces. The butylene structure ratio is usually preferably in the range of 90% by weight or less.

The styrenic block copolymer of the present invention may be mixed with other styrenic thermoplastic elastomers for the purpose of adjusting the adhesiveness, etc. within a range that does not impair the object of the present invention. Other styrene-based thermoplastic elastomers include styrene-based block copolymers other than the above; styrene / butadiene (SB), styrene / isoprene (SI), styrene / ethylene-butylene copolymer (SEB), styrene / ethylene- AB type block polymer such as propylene copolymer (SEP), styrene random copolymer such as styrene / butadiene rubber (SBR), styrene / ethylene-butylene copolymer / olefin crystal (SEBC), etc. Examples thereof include C-type styrene / olefin crystal block polymers, and hydrogenated products thereof.

In forming the adhesive layer, for example, for the purpose of controlling the adhesive property, if necessary, for example, a softening agent, an olefin resin, a silicone polymer, a liquid acrylic copolymer, a tackifier, an antiaging agent. , Hindered amine light stabilizers, ultraviolet absorbers, polyethyleneimine, fatty acid amides, phosphates, and other additives such as fillers and pigments such as calcium oxide, magnesium oxide, silica, zinc oxide, titanium oxide, etc. Can be added as appropriate. If necessary, the surface of the adhesive layer is subjected to surface treatment such as corona discharge treatment, ultraviolet ray irradiation treatment, flame treatment, plasma treatment or sputter etching treatment for the purpose of controlling adhesiveness or attaching workability. You can also

The addition of a tackifier is effective in improving the adhesive strength. However, the blending amount is appropriately determined according to the adherend to which the surface protective sheet is applied, in order to avoid the problem of adhesive residue due to the decrease in cohesive force. Usually, 0 to 40 parts by weight, and further 0 to 100 parts by weight of the styrene thermoplastic elastomer containing the styrene block copolymer.
30 parts by weight, particularly 0 to 10 parts by weight are preferred. If the adherend to which the surface protection sheet is applied is a metal plate,
It is preferable not to add a tackifier in forming the adhesive layer.

Examples of the tackifier include petroleum resins such as aliphatic copolymers, aromatic copolymers, aliphatic / aromatic copolymers and alicyclic copolymers, coumarone- Indene resin, terpene resin, terpene phenolic resin, rosin resin such as polymerized rosin, (alkyl) phenolic resin, xylene resin or hydrogenated products of these resins are generally used as adhesives. What is used can be used without particular limitation. These tackifiers may be used alone or in combination of two or more. Hydrogenated tackifiers are preferred from the viewpoints of releasability and weather resistance. The tackifier may be a commercially available blend as a blend with an olefin resin.

The compounding of a softening agent is generally effective in improving the adhesive strength. As the softening agent, for example, a low molecular weight diene polymer, polyisobutylene, hydrogenated polyisoprene,
Examples include hydrogenated polybutadiene and derivatives thereof. Examples of the derivative include O at one end or both ends.
Examples thereof include those having an H group or a COOH group, and specific examples thereof include hydrogenated polybutadiene diol, hydrogenated polybutadiene monool, hydrogenated polyisoprene diol, and hydrogenated polyisoprene monool. In particular, for the purpose of suppressing the improvement of the adhesiveness to the adherend, hydrogenated products of diene-based polymers such as hydrogenated polybutadiene and hydrogenated polyisoprene, olefin-based softening agents and the like are preferable. Specifically, Kuraray Co., Ltd. product name "Kurapren LIR-200"
Etc. are available. These softening agents may be used alone or in combination of two or more.

The molecular weight of the softening agent is not particularly limited and can be set appropriately. However, if the molecular weight becomes small, it may cause substance transfer from the adhesive layer to the adherend or heavy peeling. However, since the effect of improving the adhesive strength tends to become poor as the molecular weight increases, the number average molecular weight of the softening agent is preferably about 5,000 to 100,000, particularly preferably 10,000 to 50,000.

When a softening agent is used, its addition amount is not particularly limited. However, if the addition amount is large, the adhesive residue tends to increase at high temperatures and at the time of outdoor exposure. Therefore, the styrene type block copolymer is used. The amount is preferably 40 parts by weight or less, more preferably 20 parts by weight or less, and particularly preferably 10 parts by weight or less with respect to 100 parts by weight of the pressure-sensitive adhesive composition containing the styrene-based thermoplastic elastomer containing ss and the softening agent. When the adherend to which the surface protective sheet is applied is a metal plate, it is preferable not to add a tackifier when forming the adhesive layer.

The thickness of the adhesive layer is not particularly limited and may be appropriately determined depending on the required adhesive strength and the like. The thickness of the adhesive layer is usually about 1 to 50 μm, preferably 2
-40 μm, more preferably 5-20 μm.

The polyolefin resin forming the base material layer is not particularly limited, and for example, polypropylene or a block-type or random-type propylene-based polymer composed of a propylene component and an ethylene component; low density, high density,
Ethylene-based polymers such as linear low density polyethylene; olefin-based polymers such as ethylene-α-olefin copolymers, ethylene-vinyl acetate copolymers, ethylene-methyl methacrylate copolymers and other ethylene components and other monomers Polymers and the like can be preferably exemplified in view of problems such as film formation stability and incineration. These polyolefin resins may be used alone or in combination of two or more. Among these, the above-mentioned density 0.88 to 0.93 g
/ Cm ³ linear low density polyethylene is preferred.

For the purpose of preventing deterioration, the base material layer includes, for example, an antioxidant, a UV absorber, a light stabilizer such as a hindered amine light stabilizer, an antistatic agent, and other components such as calcium oxide. Fillers such as magnesium oxide, silica, zinc oxide and titanium oxide, additives such as pigments, eye drool inhibitors, lubricants, antiblocking agents, foaming agents and polyethyleneimine can be added as appropriate.

The thickness of the base material layer is not particularly limited, but is usually about 20 to 300 μm, preferably 30 to 25.
It is 0 μm, more preferably 40 to 200 μm. Further, the base material layer may be a single layer or may be composed of two or more layers. The back surface side of the base material layer may be subjected to uneven processing for the purpose of imparting slip resistance and handicap resistance.

The surface protective sheet of the present invention comprises a base material layer formed by using the base material layer forming material containing the polyolefin resin and the adhesive layer forming material containing a styrene block copolymer as the styrene thermoplastic elastomer. And an adhesive layer are formed by a coextrusion method. The coextrusion method can be carried out according to the inflation method, T-die method or the like generally used for film production. The base material layer and the adhesive layer are coextruded in two layers or multiple layers. The surface treatment can be applied to the base material layer and the adhesive layer, if necessary.

Further, if necessary, a separator or the like can be temporarily attached and protected on the adhesive layer until it is put into practical use. For the surface of the supporting base material to which the adhesive layer is not attached, for example, for the purpose of forming a wound body that can be easily unwound, a mold release treatment by adding fatty acid amide or polyethyleneimine to the base material layer or silicone. It is also possible to provide a coat layer made of an appropriate release agent such as a system, a long-chain alkyl system, or a fluorine system.

[0033]

EXAMPLES The present invention will be described below with reference to examples.
The present invention is not limited to these.

Example 1 Linear low-density polyethylene (Evolution-Mitsui Chemicals, Inc.)
SP2020) 0.5 parts by weight of ethylenebisstearylamide (manufactured by Nippon Kasei Co., Ltd.) per 100 parts by weight of a base layer forming material, and a block polymer of styrene / ethylene / butylene copolymer / styrene (manufactured by Asahi Kasei Corporation) , Tuftec H1221, maximum tan δ temperature = −32 ° C.) was formed by an inflation method at a die temperature of 240 ° C. to obtain a surface protective sheet. At this time, the base material layer was 110 μm, and the adhesive layer was 5 μm. In addition, linear low density polyethylene (Mitsui Chemicals, Inc., Evol-SP2020) has a density of 0.916 g / cm ³ . Styrene / ethylene-butylene copolymer / styrene block polymer (Tuftec H122 manufactured by Asahi Kasei Corporation)
In 1), the styrene content was 12% by weight, and the proportion of the butylene structure in the ethylene-butylene copolymer block was 76% by weight.

Example 2 Low-density polyethylene (Tosoh Corp., Petrosene 173)
Styrene / ethylene-butylene copolymerization with a base material layer forming material in which 0.5 parts by weight of ethylenebisstearylamide (manufactured by Nippon Kasei) and titanium oxide (manufactured by Dainichiseika, HCM2035W) were added to 100 parts by weight. Combined styrene block polymer (Tuftec H122, manufactured by Asahi Kasei Corporation)
1, the maximum tan δ temperature = -32 ° C) 100 parts by weight of a petroleum resin (Arakawa Chemical Co., Alcon P-100) was added to the adhesive layer forming material at a die temperature of 230 ° C by the T-die method. To obtain a surface protection sheet. At this time, the substrate layer was 60 μm and the adhesive layer was 10 μm. In addition, low-density polyethylene (Tosoh Corp., Petrosene 17
3) has a density of 0.924 g / cm ³ .

Example 3 Linear low-density polyethylene (Evolution-Mitsui Chemicals, Inc.)
SP2020) 0.5 parts by weight of ethylenebisstearylamide (manufactured by Nippon Kasei Co., Ltd.) per 100 parts by weight of a base layer forming material and a block polymer of styrene / ethylene / butylene copolymer / styrene (manufactured by JSR Corporation) , Dynaron 8600P, maximum tan δ temperature = −39 ° C.) with a die temperature of 220 by the T-die method.
A film was formed at 0 ° C to obtain a surface protection sheet. At this time, the substrate layer was 110 μm, and the adhesive layer was 10 μm. The styrene / ethylene-butylene copolymer / styrene block polymer (JSR Corporation, Dynaron 8600P) had a styrene content of 15% by weight and a butylene structure in the ethylene / butylene copolymer block of 67% by weight.

Comparative Example 1 In Example 1, as an adhesive layer forming material, a block polymer of styrene / ethylene / butylene copolymer / styrene (manufactured by Asahi Kasei Corp., Tuftec H1221, maximum tan δ).
Instead of (temperature = -32 ° C), a block polymer of styrene / ethylene / butylene copolymer / styrene (manufactured by Shell Elastomer Co., Ltd., Kraton G1657, maximum tan δ).
A surface protective sheet was prepared in the same manner as in Example 1 except that the temperature was -50 ° C. A block polymer of styrene / ethylene-butylene copolymer / styrene (made by Shell Elastomer Co., Ltd., Kraton G16
57) has a styrene content of 13% by weight.

Comparative Example 2 In Example 1, as an adhesive layer forming material, a block polymer of styrene / ethylene / butylene copolymer / styrene (manufactured by Asahi Kasei Corp., Tuftec H1221, maximum tan δ).
Instead of (temperature = -32 ° C), a block polymer of styrene / ethylene / butylene copolymer / styrene (manufactured by Shell Elastomer Co., Ltd., Kraton G1657, maximum tan δ).
The surface was prepared in the same manner as in Example 1 except that an adhesive composition was used in which 5 parts by weight of a petroleum resin (Arakawa Chemical Co., Alcon P-100) was added to 100 parts by weight of the temperature = -50 ° C. Created a protective sheet.

Comparative Example 3 In Example 2, as a pressure-sensitive adhesive layer forming material, a block polymer of styrene / ethylene / butylene copolymer / styrene (manufactured by Asahi Kasei Corp., Tuftec H1221, maximum tan δ).
Temperature = −32 ° C.), instead of styrene / ethylene / propylene copolymer / styrene block polymer (Co., Ltd.)
Kuraray, Septon 2063, maximum tan δ temperature = -5
Petroleum resin (Arakawa Chemical Co., Ltd.,
A surface protective sheet was prepared in the same manner as in Example 2 except that the pressure-sensitive adhesive composition containing 5 parts by weight of Alcon P-100) was used. In addition, styrene / ethylene-propylene copolymer / styrene block polymer (Co., Ltd.)
Kuraray's Septon 2063) has a styrene content of 13% by weight.

Evaluation Test (Measurement of Maximum Tan δ Temperature and Storage Elastic Modulus) Dynamic viscoelasticity measurement of each styrene block copolymer used in the adhesive layer of the surface protective sheet in the measurement temperature range of −60 to 100 ° C. The temperature at which the tan δ value is maximum and the storage elastic modulus at 20 ° C. of the adhesive layer are -60 to 150 ° C. temperature change while applying shear strain at a frequency of 1 Hz using ARES manufactured by Rheometric Scientific. A temperature rising rate of 5 ° C./min) was applied and measured. As the measurement sample, an adhesive layer having a thickness of about 5 mm was prepared and measured. The adhesive layer was formed by a casting method using an organic solvent or a hot pressing method. The storage modulus of the adhesive layer is
When these methods cannot be performed, it can be measured by a method of obtaining the difference between the storage elastic modulus of the surface protective sheet and the storage elastic modulus of the supporting substrate. The results are shown in Table 1.

(Measurement of Adhesive Strength) The adhesive strength of the surface protective sheets obtained in Examples and Comparative Examples was measured according to JIS Z 0237.
It was measured according to. Specifically, as an adherend, SUS3
A 04BA plate (smooth surface) and a SUS304HL plate (polished surface) were used. After washing the surface of the SUS plate with toluene, pressure bonding with a 2 kg roller, and after 30 minutes, measure with an Instron type tensile tester (manufactured by Shimadzu Corporation, Autograph) at a pulling speed of 300 mm / min and 180 degree peeling. did. At this time, the measurement environment and storage environment are 23 ° C / 5
Performed at 0%. 23 ° C / 5 as adhesive strength after heat resistance
The SUS304BA plate stuck at 0% was left in a dryer set at 80 ° C for 14 days, and then at 23 ° C / 50% for 2 days.
It was left for a time and measured at 23 ° C./50% in the same manner as above. The results are shown in Table 1.

[0042]

[Table 1] From Table 1, it can be seen that the surface protective sheet of the present invention has a good adhesive strength even with respect to the adherend that has been subjected to the polishing treatment, has a small increase in the adhesive strength even under heat resistance, and has a good releasability over time. Recognized to be.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tadao Torii             1-2 1-2 Shimohozumi, Ibaraki City, Osaka Prefecture Nitto             Electric Works Co., Ltd. (72) Inventor Masayoshi Natsume             1-2 1-2 Shimohozumi, Ibaraki City, Osaka Prefecture Nitto             Electric Works Co., Ltd. (72) Inventor Yuki Kobayashi             1-2 1-2 Shimohozumi, Ibaraki City, Osaka Prefecture Nitto             Electric Works Co., Ltd. F term (reference) 4F100 AK03A AK12B AK12J AK63A                       AL02B AL05A AL09B BA02                       EH20 GB90 JA06B JA13A                       JK07B JL13B JL14                 4J004 AA06 AB01 CA04 CB03 CC02                       FA04                 4J040 DM001 JA09 JB09 LA06                       MA11 NA12 PA23 PA42

Claims (3)

[Claims] 1. A surface protective sheet in which a base material layer containing a polyolefin resin and an adhesive layer containing a styrene thermoplastic elastomer are formed by coextrusion, wherein the styrene thermoplastic elastomer is -60. -10
Tan δ of dynamic viscoelasticity measurement in the measurement temperature range of 0 ° C
A surface protection sheet, which is a styrene block copolymer having a maximum value of -40 to -25 ° C or a hydrogenated product thereof. 2. The storage elastic modulus at 20 ° C. of the adhesive layer is
Surface protection sheet of claim 1, wherein it is ^{1.0 × 10 5 ~8.0 × 10 5} Pa. 3. The polyolefin resin has a density of 0.88.
~ 0.93 g / cm ³ Is a linear low density polyethylene
The surface protection sheet according to claim 1 or 2, wherein
Red.