WO2013121853A1

WO2013121853A1 - Surface protection sheet

Info

Publication number: WO2013121853A1
Application number: PCT/JP2013/051522
Authority: WO
Inventors: 公平武田; 生島　伸祐; 二郎山戸
Original assignee: 日東電工株式会社
Priority date: 2012-02-15
Filing date: 2013-01-25
Publication date: 2013-08-22
Also published as: CN103254820A

Abstract

Provided is a surface protection sheet: having excellent adhesion workability on curved surfaces, and exceptional weather resistance; and that maintains sufficient sheet strength and can easily be detached without causing trouble, such as damage, even when left in an attached state for a long period outdoors at high temperatures. This surface protection sheet has an adhesive layer formed on one surface of a base layer. The base layer includes: a whitish layer containing 50 to 95 wt% of polyethylene and 5 to 30 wt% of titanium oxide; and a blackish layer containing 50 to 99.9 wt% of polyethylene and 0.1 to 5 wt% of carbon black. The base layer has an initial yield-point strength of 15 to 50 N/25 mm at a thickness of 150 μm or less.

Description

Surface protection sheet

The present invention relates to a surface protection sheet. Specifically, the present invention relates to a surface protective sheet that is excellent in adhesion workability to a curved surface, weather resistance, peelability after long-term adhesion, and suitable for protecting a coating film of a car body or a part, a coated steel plate, etc. .

When painting finished automobiles and their parts on trucks and ships and transporting them to remote places such as overseas, the coating of dust, dirt, rain and stone particles, etc. There is a need for means for preventing damage, glossy blurring, and discoloration.

As such a preventive measure, a coating material with a wax coating material having a thickness of 5 to 20 μm is known. However, it is difficult to form a wax-based coating film with a uniform thickness, and it is difficult to obtain a uniform coating film. For this reason, there exists a problem that it is easy to get dirty, and it is weak to acid rain. In addition, since a great amount of labor is required for applying and removing the wax-based coating film, there is a problem that environmental problems such as the use of a solvent and the treatment of waste liquid are easily induced.

On the other hand, various surface protection sheets for coating films in which an adhesive layer is provided on a support film such as polyester have been proposed. According to such a sheet system, the above problem can be overcome. However, in applications that are left for a long time outdoors at high temperatures, it is difficult to peel the surface protective sheet from the coating film due to a decrease in flexibility and strength of the sheet, an increase in adhesive strength in the adhesive layer, and the like. Problems arise.

It has also been proposed to increase the strength of the support film to overcome the problems of sheet flexibility and strength reduction under high temperature outdoors (see, for example, Patent Document 1). However, the proposal has a problem that, as the initial strength of the support film is increased, the workability of adhesion to a curved surface of an automobile body or the like is lowered, and necessary basic performance is lost.

JP-A-7-118615

The problem of the present invention is that it has excellent workability for adhesion to a curved surface, and also has excellent weather resistance, and even when left in a hot outdoor environment for a long period of time, it retains sufficient sheet strength and causes troubles such as breakage. Another object of the present invention is to provide a surface protective sheet that can be easily peeled off.

The surface protective sheet of the present invention is
A surface protective sheet in which an adhesive layer is formed on one side of the base material layer,
The base material layer includes a white layer containing 50 to 95% by weight of polyethylene and 5 to 30% by weight of titanium oxide, and a black layer containing 50 to 99.9% by weight of polyethylene and 0.1 to 5% by weight of carbon black. Including
The base material layer has an initial yield strength of 15 to 50 N / 25 mm at a thickness of 150 μm or less.

In a preferred embodiment, the base material layer contains an ultraviolet absorber in a proportion of 0.1 to 2% by weight.

In a preferred embodiment, the yield point strength is 20 to 35 N / 25 mm.

According to the present invention, it is excellent in adhesion workability to a curved surface, is extremely excellent in weather resistance, and has a sufficient sheet strength even when left in a hot outdoor environment for a long time in a bonded state. And a surface protective sheet that can be easily peeled off.

In the surface protective sheet of the present invention, an adhesive layer is formed on one side of the base material layer.

The base material layer includes at least two layers of a specific white layer and a specific black layer. As a result, it has excellent workability for adhesion to curved surfaces and extremely excellent weather resistance. Even when left in a hot outdoor environment for a long period of time, it retains sufficient sheet strength and can be easily used without any trouble such as breakage. A surface protective sheet that can be peeled can be provided.

The white layer is a layer showing a white color tone. For example, the whiteness specified by JIS-L-1015 is preferably 60% or more, more preferably 70% or more, still more preferably 80% or more, Particularly preferably, it is 85% or more.

The white layer contains titanium oxide. The content of titanium oxide in the white layer is 5 to 30% by weight, preferably 6 to 20% by weight, and more preferably 6 to 15% by weight with respect to the components forming the white layer. . When the content of titanium oxide in the white layer is less than 5% by weight, the hiding power is poor, and the base material layer and the adhesive layer may be easily deteriorated by ultraviolet rays. When the content ratio of titanium oxide in the white layer exceeds 30% by weight, the moldability such as extrudability may be poor.

The white layer contains polyethylene. The polyethylene content in the white layer is 50 to 95% by weight, preferably 60 to 95% by weight, more preferably 65 to 95% by weight, based on the components forming the white layer. Particularly preferred is 70 to 95% by weight. When the polyethylene content in the white layer is less than 50% by weight, the strength is poor and the peeling workability may be inferior. When the content ratio of polyethylene in the white layer exceeds 95% by weight, the strength is excessive and the flexibility is poor, and the curved surface adhesion may be poor.

Any appropriate polyethylene can be adopted as the polyethylene contained in the white layer. Specific examples of such polyethylene include high density polyethylene (HDPE), low density polyethylene (LDPE), and linear low density polyethylene (LLDPE). Such polyethylene may use only 1 type and may use 2 or more types.

The high density polyethylene preferably has a density of 0.94 g / cm ³ or more. The low density polyethylene such as low density polyethylene (LDPE) and linear low density polyethylene (LLDPE) has a density of preferably 0.88 to 0.93 g / cm ³ , more preferably 0.895 to 0.920 g / cm ³ . cm ³ .

The white layer may contain any appropriate other resin other than polyethylene. Such other resin is preferably a polyolefin resin other than polyethylene, and more preferably polypropylene.

Any appropriate thickness can be adopted as the thickness of the white layer depending on the purpose. Such a thickness is preferably 1 to 50 μm, more preferably 3 to 40 μm, still more preferably 5 to 30 μm, and particularly preferably 10 to 30 μm.

The black layer is a layer showing a black color tone. The black layer includes carbon black. The content ratio of carbon black in the black layer is 0.1 to 5% by weight, preferably 0.1 to 3% by weight, more preferably 0.1% to the component forming the black layer. ~ 1% by weight. When the content ratio of carbon black in the black layer is less than 0.1% by weight, sufficient weather resistance may not be imparted to the resulting surface protective sheet. If the carbon black content in the black layer exceeds 5% by weight, moldability such as extrudability may be poor.

The black layer contains polyethylene. The polyethylene content in the black layer is 50 to 99.9% by weight, preferably 60 to 99% by weight, more preferably 70 to 99% by weight, based on the components forming the black layer. It is particularly preferably 80 to 99% by weight. If the polyethylene content in the black layer is less than 50% by weight, the strength is poor and the peeling workability may be poor. If the polyethylene content in the black layer exceeds 99.9% by weight, the strength becomes excessive, the flexibility is poor, and the curved surface adhesion may be poor.

Any appropriate polyethylene can be adopted as the polyethylene contained in the black layer. Specific examples of such polyethylene include high density polyethylene (HDPE), low density polyethylene (LDPE), and linear low density polyethylene (LLDPE). Such polyethylene may use only 1 type and may use 2 or more types.

The black layer may contain any appropriate other resin other than polyethylene. Such other resin is preferably a polyolefin resin other than polyethylene, and more preferably polypropylene.

Any appropriate thickness can be adopted as the thickness of the black layer according to the purpose. Such a thickness is preferably 1 to 100 μm, more preferably 5 to 70 μm, still more preferably 10 to 60 μm, and particularly preferably 20 to 50 μm.

The base material layer preferably contains an ultraviolet absorber. The content ratio of the ultraviolet absorber in the base material layer is preferably 0.1 to 2% by weight, more preferably 0.2 to 1.5% by weight, and still more preferably based on the components forming the base material layer. 0.3 to 1.0% by weight. If the content ratio of the ultraviolet absorber in the base material layer is less than 0.1% by weight, the base material layer or the pressure-sensitive adhesive layer may be easily deteriorated by ultraviolet rays, and the content ratio of the ultraviolet absorber in the base material layer If it exceeds 2% by weight, the ultraviolet absorber tends to bleed on the surface of the base material layer, which may cause a dusting phenomenon.

As the UV absorber, for example, any appropriate UV absorber such as a benzotriazole UV absorber, a hindered amine UV absorber, or a benzoate UV absorber can be adopted. Specific examples of such an ultraviolet absorber include, for example, 2- (3-t-butyl-5-methyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (3,5-di-t- Butyl-2-hydroxyphenyl) -5-chlorobenzotriazole, poly [{6- (1,1,3,3-tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl} {( 2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {(2,2,6,6-tetramethyl-4-piperidyl) imino}], dimethyl succinate 1- (2-hydroxy Ethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate, 2,4-di-t-butylphenyl-3,5-di-t-butyl-4-hydroxybenzoate, etc. Be

The base material layer may contain any appropriate additive for the purpose of preventing deterioration. Examples of such additives include antioxidants; light stabilizers such as hindered amine light stabilizers; antistatic agents; fillers such as calcium oxide, magnesium oxide, silica, and zinc oxide; pigments; A lubricant, an anti-blocking agent, a foaming agent, polyethyleneimine, and the like.

The thickness of the base material layer is preferably 10 to 150 μm, more preferably 20 to 100 μm, and still more preferably 30 to 50 μm.

The back surface side of the base material layer may be subjected to uneven processing for the purpose of imparting slip resistance and handy cut property. Furthermore, you may form various functional layers, such as a printing layer, in the back side of a base material layer.

The substrate layer has an initial yield strength of 15 to 50 N / 25 mm, preferably 20 to 35 N / 25 mm, at a thickness of 150 μm or less. If the yield point strength is less than 15 N / 25 mm, the strength is poor, the waist (self-supporting property) is weak, wrinkles easily occur during the bonding work, and the peeling workability may be inferior. When the yield point strength exceeds 50 N / 25 mm, the flexibility is poor and the workability of bonding to a curved surface may be inferior. In the present invention, the initial yield strength of the base material layer is measured based on the method described later.

Any appropriate method can be adopted as a method for forming the base material layer. Specific examples of such a formation method include film formation methods such as a T-die method and an inflation method.

Arbitrary appropriate adhesive can be employ | adopted for the adhesive used for an adhesion layer. Examples of such adhesives include known rubber adhesives, acrylic adhesives, polyester adhesives, polyurethane adhesives, polyisobutylene adhesives, styrene adhesives, olefin adhesives, and the like. It is done.

In the formation of the adhesive layer, for the purpose of controlling adhesive properties, etc., for example, a softening agent, an olefin resin, a silicone polymer, a liquid acrylic copolymer, a phosphate ester compound, a tackifier , Antioxidants, hindered amine light stabilizers, UV absorbers, polyethyleneimine, fatty acid amides, phosphate esters, fillers and pigments (eg calcium oxide, magnesium oxide, silica, zinc oxide, titanium oxide) An agent can be added as appropriate.

For example, corona discharge treatment, ultraviolet irradiation treatment, flame treatment, plasma treatment, sputter etching treatment, and other surface treatments for the purpose of adhesion control and pasting workability are performed on the adhesive layer surface as necessary. You can also.

配合 Blending of tackifier is effective for improving adhesive strength. However, the blending amount of the tackifier is appropriately determined according to the adherend to which the surface protective sheet is applied in order to avoid the occurrence of the adhesive residue problem due to the decrease in cohesive force. The blending amount of the tackifier is preferably 50% by weight or less, more preferably 30% by weight or less, and still more preferably 10% by weight or less with respect to the pressure-sensitive adhesive used in the pressure-sensitive adhesive layer. In addition, 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.

Examples of the tackifier include petroleum-based resins such as aliphatic copolymers, aromatic copolymers, aliphatic / aromatic copolymer systems and alicyclic copolymers, and coumarone-indene resins. Terpene resins, terpene phenol resins, rosin resins such as polymerized rosin, (alkyl) phenol resins, xylene resins, hydrogenated products thereof, etc. Things can be used without any particular restrictions. Only one type of tackifier may be used, or two or more types may be used. Among these tackifiers, hydrogenated tackifiers are preferable from the viewpoint of peelability and weather resistance. In addition, what is marketed as a blend with an olefin resin can also be used for a tackifier.

Softener blending is effective in improving adhesive strength. Examples of the softening agent include low molecular weight diene polymers, polyisobutylene, hydrogenated polyisoprene, hydrogenated polybutadiene, and derivatives thereof. Examples of such derivatives include those having an OH group or a COOH group at one or both ends. Specifically, hydrogenated polybutadiene diol, hydrogenated polybutadiene monool, hydrogenated polyisoprene diol, water Examples thereof include polyisoprene monool. In particular, hydrogenated products of diene polymers such as hydrogenated polybutadiene and hydrogenated polyisoprene, olefinic softeners, and the like are preferable for the purpose of suppressing the improvement in adhesiveness to the adherend. As such a softening agent, specifically, trade name “Kuraprene LIR-200” manufactured by Kuraray Co., Ltd. is available. These softeners may be used alone or in combination of two or more. The blending amount of the softening agent is preferably 40% by weight or less, more preferably 20% by weight or less, and further preferably 10% by weight or less with respect to the pressure-sensitive adhesive used in the pressure-sensitive adhesive layer. When the blending amount of the softening agent is 40% by weight or more with respect to the pressure-sensitive adhesive used in the pressure-sensitive adhesive layer, there is a possibility that the adhesive residue at the time of high temperature or outdoor exposure becomes remarkable.

The molecular weight of the softening agent can be appropriately set to any appropriate amount, but if the molecular weight is small, there is a risk of causing material transfer or heavy peeling from the adhesive layer to the adherend, while the molecular weight is large. Therefore, the softening agent has a number average molecular weight of preferably 5,000 to 100,000, more preferably 10,000 to 50,000.

The thickness of the adhesive layer may be appropriately set to any appropriate thickness according to the required adhesive strength. The thickness of the adhesive layer is preferably 1 to 50 μm, more preferably 2 to 40 μm, and still more preferably 5 to 20 μm.

The surface protective sheet of the present invention can be produced by any appropriate method. The surface protective sheet of the present invention is preferably obtained by forming the base material layer and the adhesive layer by coextrusion using the forming material for forming the base material layer and the forming material for forming the adhesive layer. It is done. The surface protective sheet of the present invention can also be obtained by applying a solution-type or emulsion-type adhesive on one side of the base material layer or transferring the adhesive layer formed on the separator to one side of the base material layer. Can be manufactured.
The structure of the surface protective sheet of the present invention is not particularly limited, and any structure of “white layer / black layer / adhesive layer” and “black layer / white layer / adhesive layer” can be adopted. . Moreover, as a base material layer, it can also be set as the layer structure of 3 or more layers which formed layers other than a black-type layer and a white-type layer. Specifically, a configuration such as “transparent resin layer / white color layer / black color layer / adhesive layer” may be employed. Furthermore, the thickness of the white layer and the black layer may be the same, and the thickness may be different (a white layer is thinner than the black layer, and a white layer is thicker than the black layer). May be.

As the co-extrusion method, it can be carried out according to the inflation method, T-die method and the like generally used for film production. The substrate layer and the pressure-sensitive adhesive layer can be subjected to the surface treatment as necessary.

If necessary, the adhesive layer can be protected by temporarily attaching a separator or the like until it is put to practical use. For the surface of the base material layer where the adhesive layer is not provided, for example, a mold release treatment by adding fatty acid amide or polyethyleneimine to the base material layer for the purpose of forming a wound body that can be easily rewound. It is also possible to provide a coat layer made of an appropriate release agent such as silicone, long chain alkyl, or fluorine.

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples.

[Example 1]
20% by weight of MFR5 low density polyethylene (Nippon Polyethylene, Novatec LD-LF640MA), white pigment (Daiichi Seika Co., Ltd., HCM2035W (titanium oxide concentration) 65 wt%)) 15 wt% (titanium oxide 9.75 wt%) and 2- (3-tert-butyl-5-methyl-2-hydroxyphenyl) -5-chlorobenzotriazole 0.3 wt% 20% by weight of MFR5 low-density polyethylene (Nippon Polyethylene, Novatec LD-LF640MA), carbon black (Mitsubishi) compared to the added base material white layer forming material and MFR0.07 high-density polyethylene (Tosoh, Nipolon Hard 6900) Chemical, carbon black “# 45”) 2% by weight, and A base black layer forming material to which 0.3% by weight of 2- (3-t-butyl-5-methyl-2-hydroxyphenyl) -5-chlorobenzotriazole was added was obtained by an inflation method (die temperature 240 ° C.). The black layer surface of the substrate layer having a thickness of 30 μm (white layer / black layer = 15 μm / 15 μm) obtained by coextrusion is subjected to corona treatment, and a 20 wt% toluene solution of a polyisobutylene pressure-sensitive adhesive is applied to the corona treatment surface. Was applied and dried at 80 ° C. for 3 minutes to form an adhesive layer having a thickness of 10 μm. In this way, a surface protective sheet was produced.
The obtained surface protective sheet had a base material layer thickness of 30 μm and an adhesive layer thickness of 10 μm.

[Example 2]
MFR5 homopolypropylene (Nippon Polypropylene, Novatec PP-FY4) 10% by weight, white pigment (Daiichi Seika Co., Ltd., HCM2035W (titanium oxide concentration 65) 15 wt% (titanium oxide 9.75 wt%) and 2- (3-tert-butyl-5-methyl-2-hydroxyphenyl) -5-chlorobenzotriazole 0.3 wt% added 10% by weight of MFR5 homopolypropylene (Nippon Polypropylene, Novatec PP-FY4), carbon black (Mitsubishi Chemical) , Carbon black “# 45”) 2% by weight, and 2- ( -T-Butyl-5-methyl-2-hydroxyphenyl) -5-chlorobenzotriazole and a base black layer forming material added thereto, and the same procedure as in Example 1 was carried out. Was made.
The obtained surface protective sheet had a base material layer thickness of 30 μm and an adhesive layer thickness of 10 μm.

Example 3
20% by weight of MFR5 homopolypropylene (Nippon Polypropylene, Novatec PP-FY4) and MFR5 low density polyethylene (Nippon Polyethylene, Novatec LD-LF640MA) with respect to MFR0.05 high density polyethylene (Tosoh, Nipolon Hard 7300A) 10% by weight, white pigment (manufactured by Dainichi Seika Co., Ltd., HCM2035W (titanium oxide concentration 65% by weight)) 15% by weight (titanium oxide 9.75% by weight), and 2- (3-t-butyl-5-methyl -2-Hydroxyphenyl) -5-chlorobenzotriazole 0.3% by weight of base material white layer forming material and MFR0.05 high density polyethylene (Tosoh Nipolon Hard 7300A), MFR5 homopolypropylene ( Nippon Polypropylene, Novatec PP-FY4) 0 wt%, MFR5 low density polyethylene (Nippon Polyethylene, Novatec LD-LF640MA) 10 wt%, carbon black (Mitsubishi Chemical, carbon black “# 45”) 2 wt%, and 2- (3-t- Thickness obtained by coextrusion with a base black layer forming material added with 0.3% by weight of butyl-5-methyl-2-hydroxyphenyl) -5-chlorobenzotriazole by an inflation method (die temperature 240 ° C.) The black layer surface of the base layer having a thickness of 25 μm (white layer / black layer = 12.5 μm / 12.5 μm) is subjected to corona treatment, and an acrylic pressure-sensitive adhesive is applied to the corona treatment surface, and then at 80 ° C. for 3 minutes. Drying treatment was performed to form a 5 μm thick adhesive layer. In this way, a surface protective sheet was produced. The acrylic pressure-sensitive adhesive was obtained by polymerizing 40 parts by weight of 2-ethylhexyl acrylate / 50 parts by weight of ethyl acrylate / 9 parts by weight of styrene / 1 part by weight of acrylic acid in an ethyl acetate by a conventional method to obtain a weight average molecular weight of 60 This was prepared by preparing 5 million polymers and adding 5 parts by weight of a trifunctional isocyanate to the solution.
The obtained surface protective sheet had a base material layer thickness of 25 μm and an adhesive layer thickness of 5 μm.

[Comparative Example 1]
MFR1 high density polyethylene (Tosoh, Nipolon Hard 5700), MFR0.05 high density polyethylene (Tosoh, Nipolon Hard 7300A) 45% by weight, white pigment (Daiichi Seika Co., Ltd., HCM2035W (Titanium oxide concentration 65% by weight) )) 1 wt% (titanium oxide 0.65 wt%) and 2- (3-tert-butyl-5-methyl-2-hydroxyphenyl) -5-chlorobenzotriazole 0.3 wt% The material layer forming material is subjected to corona treatment on one side of a base material layer having a thickness of 25 μm (white layer = 25 μm) obtained by molding the material layer forming material under a blow ratio of 5 conditions by an inflation method (die temperature: 240 ° C.) The corona-treated surface was coated with the acrylic pressure-sensitive adhesive obtained in Example 3 and dried at 80 ° C. for 3 minutes to form a 5 μm thick pressure-sensitive adhesive layer. In this way, a surface protective sheet was produced.
The obtained surface protective sheet had a base material layer thickness of 25 μm and an adhesive layer thickness of 5 μm.

〔Evaluation test〕
(Yield point strength)
About the surface protection sheet (25 mm in width) obtained in Examples and Comparative Examples, the tensile strength was examined under the conditions of a pulling speed of 300 mm / min and a chuck interval of 50 mm (MD direction). As the sample, an initial product and a product subjected to an outdoor exposure test for 6 months in Thailand (Thai exposure) were used. In the exposure test, the surface protection sheet was made of an acrylic clear coating plate (specifically, for example, the acrylic clear coating plate described above, an acrylic melamine paint for aluminum wheels (manufactured by Nippon Paint, Super rack 5000AW-10 clear) can be applied evenly using a spray gun and dried at 150 ° C. for 1 hour. The test was conducted under the condition of leaving from the month to August. The results are shown in Table 1.

(Curved surface adhesion)
Workability at the time of bonding the surface protective sheets obtained in Examples and Comparative Examples to a coated plate having a radius of 500 cm was examined and evaluated according to the following criteria. The results are shown in Table 1.
○: Adhesion treatment was easy without generating wrinkles.
(Triangle | delta): The work process was required for the adhesion process which is easy to enter a wrinkle and does not produce a wrinkle.
X: It was difficult to avoid wrinkling and difficult to adhere.

(Long-term peelability)
The surface protective sheets obtained in the examples and comparative examples were adhered to a coated plate having a radius of 500 cm, and the peeling workability after the exposure to the outdoors for 6 months was examined and evaluated according to the following criteria. The results are shown in Table 1.
○: The sheet could be smoothly peeled without being cut.
(Triangle | delta): The sheet | seat sometimes cut and it was hard to peel.
X: The sheet was very easy to cut.

(Measurement of weather resistance)
The surface protection sheets obtained in Examples and Comparative Examples were cut into strips having a width of 20 mm to prepare evaluation samples. This sample was pressed against a SUS430BA plate by reciprocating a 2 kg roller, and then put into a sunshine carbon weather meter (product of Suga Test Instruments Co., Ltd.) for 1000 hours, and then from one end of the sample to a length of 100 mm Was peeled in the 180 ° direction at a tensile speed of 0.3 m / min.
The above results were evaluated according to the following criteria. The results are shown in Table 1.
○: The sample was not broken and could be peeled off very well.
X: The sample was broken in the middle due to deterioration of the substrate, or the adhesive remained on the adherend and was contaminated.

From Table 1, the surface protective sheet of the present invention has excellent workability for adhesion to curved surfaces and extremely excellent weather resistance, and retains sufficient sheet strength even when left in a hot outdoor environment for a long time. Thus, it can be easily peeled off without any trouble such as breakage.

The surface protective sheet of the present invention is, for example, a member such as a metal plate, a painted metal plate, an aluminum sash, a resin plate, a decorative steel plate, a vinyl chloride laminated steel plate, a glass plate, etc. It can be used for purposes such as attaching to the surface to protect.

Claims

A surface protective sheet in which an adhesive layer is formed on one side of the base material layer,
The base material layer includes a white layer containing 50 to 95% by weight of polyethylene and 5 to 30% by weight of titanium oxide, and a black layer containing 50 to 99.9% by weight of polyethylene and 0.1 to 5% by weight of carbon black. Including
The base material layer has an initial yield strength of 15 to 50 N / 25 mm at a thickness of 150 μm or less.
Surface protection sheet.
The surface protective sheet according to claim 1, wherein the base material layer contains an ultraviolet absorber in a proportion of 0.1 to 2% by weight.
The surface protective sheet according to claim 1, wherein the yield point strength is 20 to 35 N / 25 mm.