JP2013189617A - Surface-protecting sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface-protecting sheet which configures a roll-wound article exhibiting a low peel rate dependence with respect to unwinding force and little elongation with respect to a base-material layer when unwinding at high speed.SOLUTION: A surface-protecting sheet configures a roll-wound article, includes a base-material layer and an adhesive layer, and is obtained by integrally forming the base-material layer and the adhesive layer using co-extrusion molding. The rate of variation of the unwinding force is within 200%. Elongation when unwinding at a peel rate of 30m/min is ≤1.5%.

Description

  The present invention relates to a surface protective sheet. In detail, this invention relates to the surface protection sheet containing a base material layer and an adhesion layer. The surface protective sheet of the present invention includes, for example, a metal plate, a paint plate, an aluminum sash, a resin plate, a decorative steel plate, a vinyl chloride laminated steel plate, a glass plate and other members, a polarizing film, an optical member such as a liquid crystal panel, and an electronic member. When transporting, processing, curing, etc., it is used for applications such as sticking to the surface for protection.

  The surface protective sheet is generally provided with an adhesive layer on one side of the base material layer. As a method for producing a surface protective sheet including such a base material layer and an adhesive layer, a method in which the base material layer and the adhesive layer are integrally formed by coextrusion molding has been proposed (for example, see Patent Document 1). .

  In general, the surface protection sheet is stored in a roll as a wound product, and is rewound during use. However, the conventional surface protection sheet has a problem that the rewinding force increases as a whole after storing the roll, and the rewinding force at high speed becomes large. There is a problem that the amount of elongation becomes large.

JP-A-61-103975

  An object of the present invention is a surface protective sheet which is a roll wound product, and is a surface protective sheet in which the unwinding force is less dependent on the peeling rate and the amount of elongation of the base material layer during rewinding at high speed is small. It is to provide.

The surface protective sheet of the present invention is
It is a surface protection sheet that is a rolled product,
Including a base material layer and an adhesive layer,
The base material layer and the adhesive layer are integrally formed by coextrusion molding,
The unwinding force variation rate measured based on the following formula is within 200%,
Fluctuation rate of unwind force (%) = P (max) / P (0.1) × 100
(However, P (max) is the maximum value of the unwinding force when the peeling speed is measured at 0.3 m / min, 1 m / min, 3 m / min, 10 m / min, and 30 m / min (N / 20 mm), and P (0.1) is the unwinding force (N / 20 mm) when measured under the condition that the peeling speed is 0.1 m / min.)
The amount of elongation at the time of unwinding at a peeling speed of 30 m / min is 1.5% or less.

  In preferable embodiment, the said base material layer contains polyolefin resin as a main component.

  In preferable embodiment, the said base material layer consists of the outermost base material layer A and the intermediate | middle base material layer B, and the said adhesion layer is arrange | positioned at this intermediate | middle base material layer B side.

  In a preferred embodiment, the outermost base material layer A contains a polyethylene resin as a main component.

  In preferable embodiment, the said polyethylene-type resin contains a low density polyethylene.

  In a preferred embodiment, the intermediate base material layer B contains a polyethylene resin as a main component.

  In preferable embodiment, the said polyethylene-type resin contains a low density polyethylene.

  In preferable embodiment, the said polyethylene-type resin contains a linear low density polyethylene.

  In a preferred embodiment, the adhesive layer contains a styrenic thermoplastic elastomer.

  In a preferred embodiment, the styrenic thermoplastic elastomer includes a styrene / ethylene-butylene copolymer / styrene copolymer (SEBS).

  In a preferred embodiment, the styrene block content in the styrene / ethylene-butylene copolymer / styrene copolymer (SEBS) is 1% by weight to 30% by weight.

  In preferable embodiment, the said adhesion layer contains a tackifier.

  In preferable embodiment, the softening point of the said tackifier is 100 degreeC or more.

  According to the present invention, there is provided a surface protective sheet which is a roll wound product, and has a small peeling rate dependency of the unwinding force, and a small amount of elongation of the base material layer at the time of rewinding at a high speed. Can be provided.

It is sectional drawing which shows typically the example of 1 structure of the surface protection sheet of this invention.

  The surface protective sheet of the present invention is a roll roll. Any appropriate size can be adopted as the size of the roll roll.

  The surface protective sheet of the present invention is a surface protective sheet including a base material layer and an adhesive layer. The surface protective sheet of the present invention may contain any appropriate other layer as long as the effects of the present invention are not impaired.

  The thickness of the base material layer is 50 μm or more, preferably 50 μm to 300 μm, more preferably 50 μm to 250 μm, still more preferably 50 μm to 200 μm, particularly preferably 50 μm to 150 μm, and most preferably. Is 50 μm to 100 μm. When the thickness of the base material layer falls within the above range, the base material layer is hardly torn or torn during rewinding, and the stiffness of the base material layer can be suppressed from increasing, so the surface protection of the present invention Floating or the like hardly occurs after the sheet is attached to the adherend.

  The thickness of the adhesive layer is preferably 1 μm to 50 μm, more preferably 2 μm to 40 μm, further preferably 3 μm to 30 μm, particularly preferably 4 μm to 20 μm, and most preferably 5 μm to 10 μm. . By keeping the thickness of the pressure-sensitive adhesive layer within the above range, it becomes easy to control the layer structure when producing the surface protective sheet of the present invention by coextrusion molding, and the surface protective sheet has sufficient mechanical strength. Can be obtained.

  The total thickness of the surface protective sheet of the present invention is preferably 50 μm to 150 μm, more preferably 53 μm to 140 μm, still more preferably 55 μm to 130 μm, particularly preferably 57 μm to 120 μm, and most preferably. Is 60 μm to 110 μm. By keeping the total thickness of the surface protective sheet of the present invention within the above range, a surface protective sheet having excellent mechanical properties and excellent handleability can be obtained.

  The surface protective sheet of the present invention is formed by integrally forming a base material layer and an adhesive layer by coextrusion molding. As the coextrusion molding, any appropriate coextrusion molding generally used for production of films, sheets and the like can be adopted. As the coextrusion molding, for example, an inflation method, a coextrusion T-die method, or the like can be adopted. These coextrusion molding is preferable in terms of cost and productivity.

In the surface protective sheet of the present invention, the fluctuation rate of the unwinding force measured based on the following formula is 200% or less, preferably 180% or less, more preferably 170% or less, and particularly preferably 165. %.
Fluctuation rate of unwind force (%) = P (max) / P (0.1) × 100
(However, P (max) is the maximum value of the unwinding force when the peeling speed is measured at 0.3 m / min, 1 m / min, 3 m / min, 10 m / min, and 30 m / min (N / 20 mm), and P (0.1) is the unwinding force (N / 20 mm) when measured under the condition that the peeling speed is 0.1 m / min.)
If the rate of fluctuation is within the above range, the unwinding force dependence of the unwinding force is small. For example, the problem seen in the conventional surface protection sheet that the unwinding force at high speed becomes large is solved. Can do. In addition, the measuring method of the said rewinding force is mentioned later.

  In the surface protective sheet of the present invention, the amount of elongation at the time of unwinding at a peeling speed of 30 m / min is 1.5% or less, preferably 1.4% or less, more preferably 1.3% or less. Particularly preferably, it is 1.2% or less, and most preferably 1.1% or less. The lower limit value of the elongation amount is preferably 0% or more. If the elongation amount falls within the above range, a surface protective sheet having a small elongation amount of the base material layer at the time of rewinding at a high speed can be provided. The method for measuring the elongation will be described later.

  In the surface protective sheet of the present invention, the unwinding force at a peeling speed of 0.1 m / min is preferably 2.5 N / 20 mm or less, more preferably 0.01 N / 20 mm to 2.3 N / 20 mm, More preferably, it is 0.1N / 20mm-2.1N / 20mm, Most preferably, it is 0.1-1.91N / 20mm. When the unwinding force at a peeling speed of 0.1 m / min is within the above range, a moderately light unwinding feeling can be obtained during unwinding at a low speed.

  The surface protective sheet of the present invention has a peeling rate of 0.3 m / min, 1 m / min, 3 m / min, 10 m / min, 30 m / min, based on the unwinding force at a peeling rate of 0.1 m / min. The amount of fluctuation of the unwinding force in each is preferably within ± 2 N / 20 mm, more preferably within ± 1.5 N / 20 mm, and even more preferably within ± 1.3 N / 20 mm. Preferably, it is within ± 1.0 N / 20 mm. Here, the fluctuation amount of the unwinding force is more specifically the peeling speed of 0.1 m / min, 0.3 m / min, 1 m / min, 3 m / min, 10 m / min, 30 m / min. The rewinding force in each is P (0.1) (N / 20mm), P (0.3) (N / 20mm), P (1) (N / 20mm), P (3) (N / 20mm) , P (10) (N / 20 mm), P (30) (N / 20 mm), P (0.3) -P (0.1) (N / 20 mm), P (1) -P ( 0.1) (N / 20 mm), P (3) -P (0.1) (N / 20 mm), P (10) -P (0.1) (N / 20 mm), P (30) -P Each of (0.1) (N / 20 mm) has a peeling rate of 0.3 m / min, 1 m / min, 3 m / min, 10 m / min, 30 m / mi. To the true amount of fluctuation of unwinding force in each. If the amount of fluctuation is within the above range, the peeling speed dependency of the unwinding force is small, and for example, the problem seen in the conventional surface protection sheet that the unwinding force at high speed becomes large is solved. Can do.

  The base material layer preferably contains a polyolefin resin as a main component. When the base material layer contains a polyolefin-based resin as a main component, it can have heat resistance, solvent resistance, and flexibility, and can easily form a rolled product. The polyolefin resin contained in the base material layer may be only one type or two or more types. The base material layer may be a single layer or a plurality of layers.

  Here, the “main component” in the present invention is preferably 50% by weight or more, more preferably 60% by weight or more, still more preferably 70% by weight or more, and particularly preferably 80% by weight or more. Yes, and most preferably 90% by weight or more.

  Examples of the polyolefin resin include a polyethylene resin, propylene or a propylene resin composed of a propylene component and an ethylene component, and an ethylene vinyl acetate copolymer.

  Specific examples of the polyolefin resin include, for example, high density polyethylene (HDPE), medium density polyethylene, low density polyethylene (LDPE), linear low density polyethylene (LLDPE), polypropylene, poly-1-butene, poly -4-methyl-1-pentene, ethylene / propylene copolymer, ethylene / 1-butene copolymer, ethylene / 1-hexene copolymer, ethylene / 4-methyl-1-pentene copolymer, ethylene / 1 -Octene copolymer, ethylene / methyl acrylate copolymer, ethylene / methyl methacrylate copolymer, ethylene / vinyl acetate copolymer, ethylene / ethyl acrylate copolymer, ethylene / vinyl alcohol copolymer, etc. It is done.

  When the base material layer is composed of two or more layers, each adjacent layer should be selected as a resin component that can form a strong bond with each other by melt coextrusion. Is preferred.

  The base material layer is preferably composed of an outermost base material layer A and an intermediate base material layer B, and the adhesive layer is disposed on the intermediate base material layer B side. That is, the laminated structure of the surface protective sheet of the present invention preferably has a three-layer structure of “outermost base material layer A / intermediate base material layer B / adhesive layer”. FIG. 1 is a cross-sectional view schematically showing a configuration example in which the surface protective sheet 100 of the present invention has a laminated configuration of “outermost base layer A21 / intermediate base layer B22 / adhesive layer 10”. The outermost base material layer A <b> 21 and the intermediate base material layer B <b> 22 become the base material layer 20.

  The outermost base material layer A is preferably a white layer. When the outermost base material layer A is a white layer, a surface protective sheet having excellent weather resistance can be obtained.

  The intermediate base material layer B is preferably a black layer. When the intermediate base material layer B is a black layer, a surface protective sheet having excellent weather resistance can be obtained.

  The base material layer is more preferably composed of an outermost base material layer A and an intermediate base material layer B. The outermost base material layer A is a white-based layer, and the intermediate base material layer B is a black-based layer. When the base material layer includes two layers of a white layer and a black layer, a surface protective sheet having extremely excellent weather resistance can be obtained.

  The white layer is a layer showing a white color tone. For example, the whiteness defined by JIS-L-1015 is preferably 60% or more, more preferably 70% or more, and still more preferably. It is 80% or more, and particularly preferably 85% or more. The white layer preferably contains a white pigment. Any appropriate white pigment can be adopted as the white pigment. An example of such a white pigment is titanium oxide. When the white layer contains a white pigment, the content is preferably 0.1% by weight to 50% by weight, more preferably 1% by weight to 40%, with respect to the resin component forming the white layer. % By weight, more preferably 2% by weight to 30% by weight. When the content ratio of the white pigment to the resin component forming the white layer falls within the above range, a surface protective sheet having excellent weather resistance can be obtained, and extrudability and other moldability are also excellent.

The resin component forming the outermost substrate layer A is preferably a polyolefin resin, more preferably a propylene polymer or an ethylene polymer. Specific examples of the resin component forming the outermost base material layer A include homopolypropylene, block polypropylene, random polypropylene, high density polyethylene (HDPE), medium density polyethylene, low density polyethylene (LDPE), and linear low Preferred is density polyethylene (LLDPE). The outermost base material layer A preferably contains a polyethylene resin as a main component. The density of the polyethylene resin is preferably 0.880 g / cm ^{3 to} 0.940 g / cm ³ , more preferably 0.880 g / cm ^{3 to} 0.923 g / cm ³ , and still more preferably 0 .880 g / cm ^{3 to} 0.915 g / cm ³ . When the outermost base material layer A contains a polyethylene resin as a main component, the base material layer can have heat resistance, solvent resistance, and flexibility, and the surface protection sheet of the present invention can be easily rolled. In addition to being able to form an object, the dependency of the unwinding force on the peeling speed can be reduced, and the amount of elongation of the base material layer during unwinding at high speed can be reduced. When the outermost base material layer A contains a polyethylene resin as a main component, the polyethylene resin preferably contains low-density polyethylene. When the polyethylene-based resin contains low-density polyethylene, the base material layer can have sufficient heat resistance, solvent resistance, and flexibility, and the surface protection sheet of the present invention can be easily formed into a roll wound form. In addition, the dependency of the unwinding force on the peeling speed can be reduced, and the amount of elongation of the base material layer during unwinding at high speed can be reduced.

  The content ratio of the polyolefin resin in the outermost base material layer A is preferably 60% by weight or more, more preferably 70% by weight or more, still more preferably 80% by weight or more, and particularly preferably 85% by weight. % Or more, and most preferably 90% by weight or more. Such polyolefin resin may use only 1 type, and may use 2 or more types.

  Arbitrary appropriate thickness can be employ | adopted for the thickness of the outermost base material layer A according to the objective. Such thickness is preferably 2 μm to 100 μm, more preferably 3 μm to 80 μm, still more preferably 4 μm to 60 μm, and particularly preferably 5 μm to 50 μm.

  The black layer is a layer showing a black color tone. The black layer preferably contains a black pigment. Any appropriate black pigment can be adopted as the black pigment. An example of such a black pigment is carbon black. When the black layer contains a black pigment, the content is preferably 0.01% by weight to 10% by weight and more preferably 0.1% by weight with respect to the resin component forming the black layer. -5% by weight, more preferably 0.5-3% by weight. When the content ratio of the black pigment to the resin component forming the black layer falls within the above range, a surface protective sheet having excellent weather resistance can be obtained, and extrudability and other moldability are also excellent.

The resin component forming the intermediate base material layer B is preferably a polyolefin-based resin, more preferably a propylene-based polymer or an ethylene-based polymer. Specific examples of the resin component forming the intermediate base material layer B include homopolypropylene, block polypropylene, random polypropylene, high density polyethylene (HDPE), medium density polyethylene, low density polyethylene (LDPE), and linear low density. Polyethylene (LLDPE) is preferred. The black layer preferably contains a polyethylene resin as a main component. The density of the polyethylene resin is preferably 0.880 g / cm ^{3 to} 0.940 g / cm ³ , more preferably 0.880 g / cm ^{3 to} 0.923 g / cm ³ , and still more preferably 0 .880 g / cm ^{3 to} 0.915 g / cm ³ . When the intermediate base material layer B contains a polyethylene-based resin as a main component, the base material layer can have heat resistance, solvent resistance, and flexibility, and the surface protection sheet of the present invention can be easily rolled. In addition, the dependency of the unwinding force on the peeling speed can be reduced, and the amount of elongation of the base material layer during unwinding at a high speed can be reduced.

  When the intermediate base material layer B contains a polyethylene resin as a main component, the polyethylene resin preferably contains low-density polyethylene. When the polyethylene-based resin contains low-density polyethylene, the base material layer can have sufficient heat resistance, solvent resistance, and flexibility, and the surface protective sheet of the present invention can be more easily rolled-rolled. While being able to form, the dependence of the unwinding force on the peeling rate can be further reduced, and the amount of elongation of the base material layer during unwinding at high speed can be further reduced.

  When the intermediate base material layer B contains a polyethylene resin as a main component, the polyethylene resin preferably contains a linear low density polyethylene. When the polyethylene-based resin contains linear low-density polyethylene, the dependency of the unwinding force on the peeling rate can be further reduced, and the elongation amount of the base material layer at the time of unwinding at high speed can be further reduced.

The density of the linear low density polyethylene is preferably 0.880 g / cm ^{3 to} 0.910 g / cm ³ , more preferably 0.880 g / cm ^{3 to} 0.905 g / cm ³ , and further preferably is ^{0.885g / cm 3 ~0.905g / cm 3} , particularly preferably from ^{0.890g / cm 3 ~0.900g / cm 3} . By keeping the density of the linear low-density polyethylene within the above range, the peeling speed dependency of the unwinding force can be further reduced, and the elongation of the base material layer at the time of unwinding at high speed can be further reduced. .

  When the intermediate base material layer B contains linear low density polyethylene, the content of the linear low density polyethylene in the intermediate base material layer B is preferably 30% by weight to 5% by weight, more preferably Is 25% by weight to 5% by weight, more preferably 20% by weight to 10% by weight, and particularly preferably 15% by weight to 10% by weight. By keeping the content ratio of the linear low density polyethylene in the intermediate base material layer B within the above range, the peeling speed dependency of the rewinding force can be further reduced, and the base material layer at the time of rewinding at high speed can be reduced. The amount of elongation can be further reduced.

  The content ratio of the polyolefin resin in the intermediate base material layer B is preferably 60% by weight or more, more preferably 70% by weight or more, still more preferably 80% by weight or more, and particularly preferably 85% by weight. Or more, and most preferably 90% by weight or more. Such polyolefin resin may use only 1 type, and may use 2 or more types.

  Arbitrary appropriate thickness can be employ | adopted for the thickness of the intermediate | middle base material layer B according to the objective. Such thickness is preferably 2 μm to 100 μm, more preferably 3 μm to 80 μm, still more preferably 4 μm to 60 μm, and particularly preferably 5 μm to 50 μm.

  The base material layer may contain any appropriate additive. Examples of such additives include antioxidants, ultraviolet absorbers, anti-aging agents, light stabilizers, antistatic agents, surface lubricants, leveling agents, plasticizers, low molecular weight polymers, corrosion inhibitors, and polymerization prohibitions. Agents, silane coupling agents, inorganic and organic fillers (eg, calcium oxide, magnesium oxide, silica, zinc oxide, titanium oxide, etc.), metal powders, colorants, pigments, heat stabilizers, anti-spot agents, lubricants And anti-blocking agents.

  A back surface treatment may be applied to the outermost layer on the side opposite to the adhesive layer of the base material layer. Any appropriate method can be adopted as the back surface processing method as long as the effects of the present invention are not impaired. Examples of the back treatment method include surface processing such as embossing and uneven processing, a method of containing a fatty acid derivative, and the like. Only one kind of such fatty acid derivative may be used, or two or more kinds thereof may be used.

  When the base material layer contains a fatty acid derivative, the content ratio of the fatty acid derivative in the base material layer is preferably 0.05% by weight to 1.00% by weight with respect to the resin component in the base material layer, More preferably, it is 0.10 weight%-0.90 weight%, More preferably, it is 0.30 weight%-0.80 weight%. If the content ratio of the fatty acid derivative in the base material layer is within the above range with respect to the resin component in the base material layer, the roll-shaped surface protection sheet of the present invention can be easily rewound. Thus, the mold release effect can be sufficiently exhibited, and the contamination of the fatty acid derivative by bleeding can be sufficiently suppressed.

  The fatty acid derivative refers to a compound containing a fatty acid derivative structure in the molecular structure.

  Examples of the fatty acid derivatives include saturated fatty acid bisamides, unsaturated fatty acid bisamides, aromatic bisamides, substituted ureas, and fatty acid metal salts. Specific examples of fatty acid derivatives include methylene bis stearamide, ethylene bis stearamide, ethylene bis oleate, N, N-dioleyl adipamide, N-stearyl-N′-stearyl urea, and the like. N-stearyl-N′-stearylamide, zinc stearate and the like.

  The fatty acid derivative is preferably a fatty acid amide, more preferably at least one selected from methylene bis stearic acid amide, ethylene bis stearic acid amide, and N-stearyl-N′-stearyl acid amide.

  The fatty acid derivative preferably has a melting point of 100 ° C. or higher. A fatty acid derivative having a melting point of less than 100 ° C. has a significant transfer to the surface of the adhesive layer, and there is a risk that a decrease in adhesive strength is likely to occur.

  The adhesive layer preferably contains a thermoplastic resin as a main component. The thermoplastic resin contained in the adhesive layer may be only one type or two or more types.

  Any appropriate thermoplastic resin can be adopted as the thermoplastic resin. Examples of such thermoplastic resins include olefin resins, aromatic group-containing olefin / diene copolymers, styrene resins, ester resins, and the like. Among these thermoplastic resins, styrene resins are preferable, and styrene thermoplastic elastomers are more preferable. By employing a styrenic thermoplastic elastomer as the thermoplastic resin, it is possible to reduce the dependency of the unwinding force on the peeling speed, and to reduce the amount of elongation of the base material layer during unwinding at a high speed.

  Preferred examples of the styrenic thermoplastic elastomer include hydrogenated styrene / butadiene rubber (HSBR), styrenic block copolymers, and hydrogenated products thereof.

  Examples of styrene block copolymers include styrene ABA block copolymers (triblock copolymers) such as styrene / butadiene / styrene copolymers (SBS) and styrene / isoprene / styrene copolymers (SIS). ); Styrenic ABAB type block copolymer (tetrablock copolymer) such as styrene / butadiene / styrene / butadiene copolymer (SBSB), styrene / isoprene / styrene / isoprene copolymer (SISI); styrene / butadiene・ Styrene-based ABABA block copolymer (pentablock copolymer) such as styrene / butadiene / styrene copolymer (SBSBS), styrene / isoprene / styrene / isoprene / styrene copolymer (SISIS); Styrene group having repeating units Click copolymers; and the like.

  Examples of hydrogenated styrenic block copolymers include styrene / ethylene-butylene copolymer / styrene copolymer (SEBS), styrene / ethylene-propylene copolymer / styrene copolymer (SEPS), and styrene. -Ethylene-butylene copolymer-Styrene-ethylene-butylene copolymer copolymer (SEBSEB);

  The styrene thermoplastic elastomer is particularly preferably a styrene / ethylene-butylene copolymer / styrene copolymer (SEBS). By adopting styrene / ethylene-butylene copolymer / styrene copolymer (SEBS) as the styrenic thermoplastic elastomer, the dependence of the unwinding force on the peeling speed can be further reduced, and the substrate at the time of rewinding at high speed. The amount of elongation of the layer can be made smaller.

  Only one type of styrenic thermoplastic elastomer may be used, or two or more types may be used.

  The styrene content in the styrenic thermoplastic elastomer (styrene block content in the case of a styrene block copolymer) is preferably 1 to 40% by weight, more preferably 5 to 40% by weight, Preferably, it is 7 to 30% by weight, more preferably 9 to 20% by weight, particularly preferably 9 to 15% by weight, and most preferably 9 to 13% by weight. . When the styrene content decreases, there is a risk that adhesive residue due to insufficient cohesive force of the adhesive layer is likely to occur. When the styrene content increases, the pressure-sensitive adhesive layer becomes hard, and there is a possibility that good adhesion to a rough surface cannot be obtained. When the styrene block content falls within the above range, the peeling speed dependency of the unwinding force can be made smaller, and the elongation amount of the base material layer at the time of unwinding at a high speed can be made smaller.

  As the styrene-based thermoplastic elastomer, hydrogenation of a styrene-based block copolymer having a repeating structure (ABA type, ABAB type, ABABA type, etc.) more than a triblock copolymer composed of styrene (A) and butadiene (B). Goods (SEBS, SEBSEB, SEBSEBS, etc.) are preferred. By adopting such a styrene-based thermoplastic elastomer, it is possible to reduce the dependency of the unwinding force on the peeling speed, and to reduce the elongation of the base material layer during unwinding at a high speed.

  Hydrogenated product of styrene-based block copolymer in which the styrene-based thermoplastic elastomer has a repetitive structure (ABA type, ABAB type, ABABA type, etc.) of a triblock copolymer or more composed of styrene (A) and butadiene (B) (SEBS, SEBSEB, SEBSEBS, etc.) The proportion of the butylene structure in the ethylene-butylene copolymer block is preferably 60% by weight or more, more preferably 70% by weight or more, and even more preferably 75. % By weight or more. When the proportion of the butylene structure in the ethylene-butylene copolymer block falls within the above range, the peeling rate dependency of the unwinding force can be further reduced, and the amount of elongation of the base material layer during unwinding at high speed can be reduced. It can be made even smaller. The proportion of the butylene structure in the ethylene-butylene copolymer block is preferably 90% by weight or less.

  The pressure-sensitive adhesive layer may contain other styrenic thermoplastic elastomers within the range that does not impair the object of the present invention for the purpose of adjusting the adhesiveness.

  Other styrene thermoplastic elastomers include styrene block copolymers other than those described above; styrene / butadiene copolymers (SB), styrene / isoprene copolymers (SI), and copolymers of styrene / ethylene-butylene copolymers. AB block polymers such as polymers (SEB) and styrene / ethylene-propylene copolymer (SEP); styrene random copolymers such as styrene / butadiene rubber (SBR); styrene / ethylene-butylene copolymer Examples thereof include ABC type styrene / olefin crystal block polymers such as a polymer / olefin crystal copolymer (SEBC); hydrogenated products thereof.

  In the formation of the adhesive layer, for the purpose of controlling adhesive properties, etc., for example, softening agents, tackifiers, polyolefin resins such as those used for the base material layer, silicone polymers, liquid acrylic copolymers are used. Polymer, Phosphate ester compound, Anti-aging agent, Light stabilizer, UV absorber, Surface lubricant, Leveling agent, Plasticizer, Low molecular weight polymer, Antioxidant, Corrosion inhibitor, Polymerization inhibitor, Silane cup Additives such as ring agents, inorganic and organic fillers (for example, calcium oxide, magnesium oxide, silica, zinc oxide, titanium oxide, etc.), metal powder, colorants, pigments, heat stabilizers, etc. may be added as appropriate. it can.

  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.

  In the surface protective sheet of the present invention, the pressure-sensitive adhesive layer preferably contains a tackifier. When the pressure-sensitive adhesive layer contains a tackifier, the peeling speed dependency of the rewinding force can be further reduced, and the amount of elongation of the base material layer during rewinding at high speed can be further reduced. The formulation of the tackifier is effective for improving the 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 compounding amount of the tackifier is preferably 80% by weight or less, more preferably 40% by weight or less, and further preferably 20% by weight or less with respect to the base polymer of 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.

  In the surface protective sheet of the present invention, the tackifier that the pressure-sensitive adhesive layer can contain has a softening point of preferably 100 ° C. or higher, more preferably 105 ° C. or higher, more preferably 110 ° C. or higher, particularly Preferably it is 115 degreeC or more. The upper limit value of the softening point is, for example, preferably 300 ° C. or lower, more preferably 250 ° C. or lower, and further preferably 200 ° C. or lower. When the softening point of the tackifier that can be contained in the adhesive layer falls within the above range, the dependency of the unwinding force on the peeling speed can be further reduced, and the amount of elongation of the base material layer during rewinding at high speed can be further reduced. .

  The blending of the softener is effective for improving the 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 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. Since there exists a tendency for it to become scarce at the improvement effect of adhesive force, the number average molecular weight of a softener becomes like this. Preferably it is 5000-100,000, More preferably, it is 10,000-50,000.

  When using a softener, the amount added can be appropriately set to any appropriate amount. However, as the amount added increases, the adhesive residue tends to increase at high temperatures and when exposed outdoors. On the other hand, it is preferably 100% by weight or less, more preferably 60% by weight or less, and still more preferably 40% by weight or less. In addition, when the adherend to which the surface protective sheet is applied is a metal plate, it is preferable not to add a softener when forming the adhesive layer.

  A polyolefin-based resin may be added to the adhesive layer for the purpose of suppressing an increase in adhesive force. Examples of the polyolefin resin can be the same as those used for forming the base material layer. This polyolefin resin may be only one kind or two or more kinds. The blending amount of the polyolefin resin is preferably 50% by weight or less, more preferably 30% by weight or less, and further preferably 20% by weight or less with respect to the base polymer of the adhesive layer.

  If necessary, a separator or the like can be temporarily attached to the adhesive layer until it is put to practical use.

  The method for producing the surface protective sheet of the present invention is preferably produced by integrally forming the base material layer and the adhesive layer by coextrusion molding. Thereby, the surface protection sheet of the laminated structure which has predetermined | prescribed thickness can be manufactured highly efficiently and cheaply. As the coextrusion molding, any appropriate coextrusion molding generally used for production of films, sheets and the like can be adopted. As the coextrusion molding, for example, an inflation method, a coextrusion T-die method, or the like can be adopted.

  According to the co-extrusion molding, the outermost surface on the opposite side of the adhesive layer of the base material layer and the adhesive layer are not in contact with each other in the melt-heated state. There is no production of by-products and no transfer of the by-products to the adhesive layer, and excellent unwinding properties are exhibited, and contamination of the adhesive layer surface can be suppressed.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples at all.

(Density measurement)
The density (g / cm ³ ) of the resin was a value measured according to ISO 1183.

(Measurement of unwinding force)
The unwinding force at each peeling speed of 0.1 m / min, 0.3 m / min, 1 m / min, 3 m / min, 10 m / min, and 30 m / min was measured as follows.
Based on JIS-Z0237 (2000), an unwinding force (N / 20 mm) of a roll product (roll width: 20 mm, length: 50 m) of a surface protection sheet was measured using an Instron type tensile tester (manufactured by Shimadzu Corporation, Auto Graph). The measurement was performed under the environment of 23 ° C. × 50% RH and the rewinding was performed so that the angle between the sheet to be rewound and the roll surface was vertical under the above speed condition.

(Calculation of fluctuation rate of rewind force)
The fluctuation rate of the unwinding force was calculated as follows.
Fluctuation rate of unwind force (%) = P (max) / P (0.1) × 100
However, P (max) is the maximum value of the unwinding force (N / min) when the peeling speed is measured under the respective conditions of 0.3 m / min, 1 m / min, 3 m / min, 10 m / min, and 30 m / min. 20 mm), and P (0.1) is the unwinding force (N / 20 mm) when measured under the condition that the peeling speed is 0.1 m / min.

(Measurement of elongation of base material layer)
The elongation amount of the base material layer during rewinding at a peeling speed of 30 m / min was measured as follows.
A tensile test according to JIS-K-7127 was performed. As a measurement sample, a surface protection sheet cut into the shape of test piece type 2 described in JIS-K-7127 was used, and the measurement was performed at a chuck interval of 50 mm, a test piece width of 20 mm, and a test speed of 300 mm / min. Moreover, the testing machine used for the measurement was an Instron type tensile testing machine (manufactured by Shimadzu Corporation, Autograph). From the SS curve obtained by measurement, the amount of elongation at 1N, 2N, 3N, 4N, 5N, 6N (/ 20 mm) can be measured, and the amount of elongation (%) at 1-6 N / 20 mm can be calculated. A calibration curve was created as follows. Next, the unwinding force at 30 m / min described above was measured, and the amount of elongation at the time of unwinding was measured from the numerical value of the obtained unwinding force (N / 20 mm) and the calibration curve of the SS curve.

(Coextrusion molding conditions)
In Examples and Comparative Examples, molding was performed by an inflation method according to the following melting temperature conditions.
Base material layer: 165 ° C
Adhesive layer: 165 ° C
Coextrusion temperature: 165 ° C

[Example 1]
Low density polyethylene (made by Tosoh, trade name: Petrocene 186R, density = 0.924 g / cm ³ ) and white pigment (titanium oxide, manufactured by DuPont, trade name: Ti-Pure R103) are contained in the proportions shown in Table 1. The white layer forming material was obtained by blending.
Next, low-density polyethylene (trade name: Petrocene 186R, density = 0.924 g / cm ³ ) and linear low-density polyethylene (product name: Excellen FX FX307, density = 0.890 g, manufactured by Tosoh Corporation) / Cm ³ ) and carbon black MB (manufactured by Sumika Color Co., Ltd., trade name: black SPEMB-865, carbon content 20%) were blended in the content ratio shown in Table 1 to obtain a black-based layer forming material.
Furthermore, SEBS (hydrogenated SEBS, styrene content = 15% by weight, manufactured by JSR, trade name: Dynalon 8600P) and 82% by weight and a tackifier (C5 hydrogenated aromatic petroleum resin, manufactured by Idemitsu Kosan, trade name: Imabu P140) , Softening point = 140 ° C.) was mixed with 18% by weight to obtain an adhesive layer forming material.
Using the white-type layer forming material, black-type layer forming material, and adhesive layer-forming material obtained above, co-extrusion molding by the inflation method is performed to obtain a roll wound product (three-layer structure (white type layer / black color) A surface protective sheet (1) (thickness: white layer / black layer / adhesive layer = 20 μm / 35 μm / 5 μm), which is a rolled product of the system layer / adhesive layer), was obtained.
The results are shown in Table 1.

[Example 2]
A surface protective sheet that is a roll wound product of a three-layer structure (white layer / black layer / adhesive layer), except that the composition of the white layer forming material is changed as shown in Table 1. (2) (Thickness: white layer / black layer / adhesive layer = 20 μm / 35 μm / 5 μm) was obtained.
The results are shown in Table 1.

Example 3
A surface protective sheet (3), which is a roll wound product having a three-layer structure (white layer / black layer / adhesive layer), except that the thickness of each layer is changed as shown in Table 1. (Thickness: white layer / black layer / adhesive layer = 20 μm / 45 μm / 5 μm) was obtained.
The results are shown in Table 1.

Example 4
The composition of the white layer forming material was changed as shown in Table 1, and the same procedure as in Example 1 was performed except that the thickness of each layer was changed as shown in Table 1. A three-layer structure (white layer / black layer / A surface protective sheet (4) (thickness: white layer / black layer / adhesive layer = 20 μm / 45 μm / 5 μm) which is a roll of the adhesive layer was obtained.
The results are shown in Table 1.

Example 5
SEBS (hydrogenated SEBS, styrene content = 15 wt%, manufactured by JSR, trade name: Dynalon 8600P) and tackifier (C5 hydrogenated aromatic petroleum resin, manufactured by Idemitsu Kosan Co., Ltd.) Name: Imabu P140, softening point = 140 ° C. 30% by weight, and the same procedure as in Example 1 was used except that an adhesive layer forming material was used. Three-layer structure (white layer / black layer) A surface protective sheet (5) (thickness: white layer / black layer / adhesive layer = 20 μm / 35 μm / 5 μm) which is a rolled product of / adhesive layer) was obtained.
The results are shown in Table 1.

Example 6
A surface protective sheet (6) which is a roll wound product having a three-layer structure (white layer / black layer / adhesive layer) except that the thickness of each layer is changed as shown in Table 1. (Thickness: white layer / black layer / adhesive layer = 15 μm / 50 μm / 5 μm) was obtained.
The results are shown in Table 1.

Example 7
As an adhesive layer forming material, SEBS (hydrogenated SEBS, styrene content = 15% by weight, manufactured by JSR, trade name: Dynalon 8600P) and 82% by weight and a tackifier (made by Eastman Chemical, trade name: C115W, softening point = 115) ° C.) A roll wound product having a three-layer structure (white layer / black layer / adhesive layer) was carried out in the same manner as in Example 1 except that the adhesive layer forming material obtained by blending 18% by weight was used. A surface protective sheet (7) (thickness: white layer / black layer / adhesive layer = 20 μm / 35 μm / 5 μm) was obtained.
The results are shown in Table 1.

Example 8
A surface protective sheet (8), which is a roll wound product having a three-layer structure (white layer / black layer / adhesive layer), except that the thickness of each layer is changed as shown in Table 1. (Thickness: white layer / black layer / adhesive layer = 15 μm / 50 μm / 5 μm) was obtained.
The results are shown in Table 1.

Example 9
Low density polyethylene (made by Tosoh, trade name: Petrocene 186R, density = 0.924 g / cm ³ ) and white pigment (titanium oxide, made by DuPont, trade name: Ti-Pure R103) are contained in the proportions shown in Table 3. The white layer forming material was obtained by blending.
Next, low density polyethylene (product of Tosoh, trade name: Petrocene 186R, density = 0.924 g / cm ³ ) and carbon black MB (product of Sumika Color, trade name: black SPEMB-865, carbon content 20%) Were blended in the proportions shown in Table 3 to obtain a black layer forming material.
Furthermore, HSBR (styrene content = 10% by weight, manufactured by JSR, trade name: Dynalon 1321P) and 82% by weight and a tackifier (C5-based hydrogenated aromatic petroleum resin, Eastman Chemical, trade name: EASTOTAC C115W) 18% by weight % To obtain an adhesive layer forming material.
Using the white-type layer forming material, black-type layer forming material, and adhesive layer-forming material obtained above, co-extrusion molding by the inflation method is performed to obtain a roll wound product (three-layer structure (white type layer / black color) A surface protective sheet (9) (thickness: white layer / black layer / adhesive layer = 20 μm / 35 μm / 5 μm), which is a rolled product of the system layer / adhesive layer), was obtained.
The results are shown in Table 3.

Example 10
The composition of the white layer forming material was changed as shown in Table 3, and the same procedure as in Example 9 was performed except that the thickness of each layer was changed as shown in Table 3. A three layer structure (white layer / black layer / A surface protective sheet (10) (thickness: white layer / black layer / adhesive layer = 20 μm / 45 μm / 5 μm) which is a roll of the adhesive layer was obtained.
The results are shown in Table 3.

Example 11
Performed in the same manner as in Example 9 except that IEMAB P140 (C5 hydrogenated aromatic petroleum resin, manufactured by Idemitsu Kosan Co., Ltd.) was used in place of EASTOTAC C115W as a tackifier, and a three-layer structure (white layer / black type) Layer / adhesive layer) surface protective sheet (11) (thickness: white layer / black layer / adhesive layer = 20 μm / 35 μm / 5 μm).
The results are shown in Table 3.

Example 12
The composition of the white layer forming material was changed as shown in Table 3, and the same procedure as in Example 9 was performed except that the thickness of each layer was changed as shown in Table 3. A three layer structure (white layer / black layer / A surface protective sheet (12) (thickness: white layer / black layer / adhesive layer = 20 μm / 45 μm / 5 μm) which is a roll of the adhesive layer was obtained.
The results are shown in Table 3.

[Comparative Example 1]
A white layer forming material was obtained in the same manner as in Example 1 except that the composition of the white layer forming material was changed as shown in Table 2.
Next, a black layer forming material was obtained in the same manner as in Example 1 except that the composition of the black layer forming material was changed as shown in Table 2.
A white layer forming material was obtained in the same manner as in Example 1 except that the composition of the white layer forming material was changed as shown in Table 2.
Next, it carried out similarly to Example 1 and the black type | system | group layer forming material was obtained.
A base film (thickness: white color layer / black color system) having a two-layer structure (white color layer / black color layer) by the inflation method using the white color layer formation material and black color layer formation material obtained above. Layer = 50 μm / 15 μm).
Further, 80% by weight of natural rubber cracked with Mn = 150,000, Mw = 820,000, Mw / Mn = 5.7 and a tackifier (C5 aliphatic hydrocarbon hydrogenated petroleum resin, manufactured by Arakawa Chemical, (Product name: Alcon P100) 20% by weight was mixed, and a solution dissolved in toluene so that the solid content concentration was 25% was prepared. The thickness of the adhesive layer after drying on the base film was 5 μm. It was coated and dried (90 ° C. × 3 min) to obtain a surface protection sheet (C1) (thickness: white layer / black layer / adhesive layer = 50 μm / 15 μm / 5 μm) as a roll roll. .
The results are shown in Table 2.

[Comparative Example 2]
A surface protective sheet (C2) which is a roll wound product having a three-layer structure (white layer / black layer / adhesive layer), except that the thickness of each layer is changed as shown in Table 2. (Thickness: white layer / black layer / adhesive layer = 55 μm / 20 μm / 5 μm) was obtained.
The results are shown in Table 2.

[Comparative Example 3]
A white layer forming material was obtained in the same manner as in Example 1 except that the composition of the white layer forming material was changed as shown in Table 2.
Next, a black layer forming material was obtained in the same manner as in Example 1 except that the composition of the black layer forming material was changed as shown in Table 2.
A base film (thickness: white color layer / black color system) having a two-layer structure (white color layer / black color layer) by the inflation method using the white color layer formation material and black color layer formation material obtained above. Layer = 60 μm / 15 μm).
Furthermore, 80% by weight of natural rubber cracked with Mw = 150,000, Mw = 820,000, Mw / Mn = 5.7 and a tackifier (rosin-based tackifier, manufactured by Arakawa Chemical Co., Ltd., trade name: Pine Crystal KE) -100) 20% by weight is mixed, and a solution dissolved in toluene so as to have a solid content concentration of 25% is prepared, so that the thickness of the adhesive layer after drying on the base film becomes 5 μm. It was coated and dried (90 ° C. × 3 min) to obtain a surface protection sheet (C3) (thickness: white layer / black layer / adhesive layer = 60 μm / 15 μm / 5 μm) as a roll.
The results are shown in Table 2.

  From Table 1, Table 2, and Table 3, the surface protection sheet of the present invention is a surface protection sheet that is a roll wound product, and has a small peeling speed dependency of the unwinding force, and the elongation at the time of rewinding at high speed. The amount is small.

  The surface protective sheet of the present invention includes, for example, a metal plate, a paint plate, an aluminum sash, a resin plate, a decorative steel plate, a vinyl chloride laminated steel plate, a glass plate and other members, a polarizing film, an optical member such as a liquid crystal panel, and an electronic member. When transporting, processing, curing, etc., it is used for applications such as sticking to the surface for protection.

100 Surface protective sheet 10 Adhesive layer 20 Base material layer 21 Outermost base material layer A
22 Intermediate base material layer B

Claims (13)

It is a surface protection sheet that is a rolled product,
Including a base material layer and an adhesive layer,
The base material layer and the adhesive layer are integrally formed by coextrusion molding,
The unwinding force variation rate measured based on the following formula is within 200%,
Fluctuation rate of unwind force (%) = P (max) / P (0.1) × 100
(However, P (max) is the maximum value of the unwinding force when the peeling speed is measured at 0.3 m / min, 1 m / min, 3 m / min, 10 m / min, and 30 m / min (N / 20 mm), and P (0.1) is the unwinding force (N / 20 mm) when measured under the condition that the peeling speed is 0.1 m / min.)
The elongation at the time of unwinding at a peeling speed of 30 m / min is 1.5% or less,
Surface protection sheet.   The surface protection sheet according to claim 1, wherein the base material layer contains a polyolefin-based resin as a main component.   The surface protection sheet according to claim 1 or 2, wherein the base material layer comprises an outermost base material layer A and an intermediate base material layer B, and the adhesive layer is disposed on the intermediate base material layer B side.   The surface protection sheet of Claim 3 in which the said outermost base material layer A contains a polyethylene-type resin as a main component.   The surface protection sheet of Claim 4 in which the said polyethylene-type resin contains a low density polyethylene.   The surface protection sheet in any one of Claim 3-5 in which the said intermediate | middle base material layer B contains a polyethylene-type resin as a main component.   The surface protection sheet according to claim 6 in which said polyethylene system resin contains low density polyethylene.   The surface protection sheet of Claim 6 or 7 in which the said polyethylene-type resin contains a linear low density polyethylene.   The surface protection sheet in any one of Claim 1-8 in which the said adhesion layer contains a styrene-type thermoplastic elastomer.   The surface protection sheet according to claim 9, wherein the styrenic thermoplastic elastomer includes a styrene / ethylene-butylene copolymer / styrene copolymer (SEBS).   The surface protection sheet according to claim 10, wherein the styrene block content in the styrene / ethylene-butylene copolymer / styrene copolymer (SEBS) is 1% by weight to 30% by weight.   The surface protection sheet in any one of Claim 1-11 in which the said adhesion layer contains a tackifier. The surface protection sheet of Claim 12 whose softening point of the said tackifier is 100 degreeC or more.

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