KR20190058710A - Self-adhesive surface protection film - Google Patents

Abstract

The self-adhesive surface protective film of the present invention is obtained by laminating an adhesive layer on one side of a base layer containing a polypropylene resin and a release layer on the opposite side by coextrusion, wherein the resin constituting the adhesive layer is styrene A hydrogenated product of a block copolymer having a butadiene-based polymer block, and a polyethylene-based resin, wherein the content of the styrene-based elastomer in the adhesive layer is 35 mass% or more and 99 mass %, The content of the polyethylene-based resin is 1% by mass or more and 65% by mass or less, and the sum of the ethylene component and the polyethylene-based resin in the styrene-based elastomer is 35% by mass or more and less than 70% by mass in the adhesive layer component.

Description

Self-adhesive surface protective film {SELF-ADHESIVE SURFACE PROTECTION FILM}

The present invention relates to an adhesive film. The pressure-sensitive adhesive film of the present invention can be suitably used in various fields such as a member such as a prism sheet used for optical use, a synthetic resin plate (for example, for building materials), a stainless steel plate (for building materials, for example) , To protect the surface of glass plates, home appliances, precision machinery, and automobile bodies at the time of manufacture, to protect against scratches during lamination, storage, transport or transport in the manufacturing process, It can be suitably used in the case of protecting from scratches occurring in a case (for example, a bending process or a press process).

BACKGROUND ART [0002] Adhesive films for the purpose of protecting the surface of a cover have conventionally been used for processing, storage, and transportation of building materials, electric appliances, electronic products, automobiles, etc. Such adhesive films have good adhesiveness, The surface should be easily removable without contamination with an adhesive.

In recent years, the cover body has been diversified, and many of the cover bodies have not only a smooth surface but also surface irregularities. As the cover having the surface irregularities, for example, a prismatic lens portion of a prism sheet used for an optical member can be given. In order to develop a sufficient adhesive force in use for a cover having surface irregularities such as a prism sheet, it is conceivable to increase the adhesive strength of the adhesive layer so that the adhesive force is obtained even if the contact area is small.

In order to increase the adhesive strength of the adhesive layer, it is possible to use a styrene-based elastomer or the like as a resin as a main component. However, when the adhesive strength of the adhesive layer is increased, the film is kept in a roll state, And the film is partially elongated or deformed.

As the countermeasure described above, a fluororesin, a silicone resin (see, for example, Patent Document 1), an ultra-high molecular polydimethylsiloxane (see, for example, Patent Document 2), a saturated fatty acid bisamide However, there is a possibility that these resins migrate into the adhesive layer when they are all stored in the roll state, and the adhesive strength may be lowered or the cover body may be contaminated (see, for example, Patent Document 3) You can not wash away your concerns.

In addition, although it has been studied to add a polyethylene resin to the adhesive layer (see, for example, Patent Document 4, Patent Document 5, etc.), both of the adhesive force to the prism and the film are kept in a roll state, It did not satisfy all of the above problems at the time of disassembling.

Japanese Patent Application Laid-Open No. 2008-81589 Japanese Patent Application Laid-Open No. 2008-308559 Japanese Patent No. 4565058 Japanese Patent Application Laid-Open No. 08-73822 Japanese Patent Laid-Open No. 2007-161882

A problem to be solved by the present invention is to provide a pressure sensitive adhesive sheet which exhibits a strong adhesive force to a cover body and which can be used for various cover bodies while keeping the pressure sensitive adhesive film in a roll state, And the like, and it is an object of the present invention to provide a self-adhesive surface protective film excellent in processability of a film.

As a result of intensive studies, the inventors of the present invention have found that the aforementioned problems can be solved by setting the kind and blending ratio of the resin used in the adhesive layer to a predetermined range, and have reached the present invention.

That is, the present invention provides a pressure-sensitive adhesive sheet comprising a substrate layer comprising a polypropylene resin, an adhesive layer formed on one side of the base layer and a release layer on the opposite side thereof laminated by coextrusion, wherein the resin constituting the adhesive layer comprises a styrene- Wherein the styrene elastomer is a hydrogenated product of a block copolymer having a styrene-based polymer block and a butadiene-based polymer block, or a block copolymer having a styrene-based polymer block and a random copolymer block of styrene and butadiene Wherein the polyethylene resin is an ethylene homopolymer and / or an ethylene-alpha olefin copolymer, the content of the styrene elastomer in the adhesive layer is 35 mass% or more and 99 mass% or less, and the content of the polyethylene- 1% by mass or more and 65% by mass or less, and the ethylene component and the polyethylene component in the styrene elastomer Fingers sum is directed to a self-adhesive surface protective film, characterized in that less than 70% by mass to 35% by weight of the adhesive layer components.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a pressure-sensitive adhesive sheet which exhibits a strong adhesive force to a cover body and which can be used for various kinds of cover bodies while keeping the pressure-sensitive adhesive film in a roll state, It is possible to obtain a self-adhesive surface protective film excellent in processability of the film.

In this case, the flexural modulus of the ethylene-based resin used in the adhesive layer is preferably 10 MPa or more and less than 90 MPa.

In this case, it is preferable that the MFR (190 DEG C, 2.16 kgf) of the polyethylene resin in the pressure-sensitive adhesive layer is 0.5 to 8 g / 10 min.

In this case, it is preferable that the MFR (230 DEG C, 2.16 kgf) of the styrene-based elastomer in the pressure-sensitive adhesive layer is 0.5 to 8 g / 10 min.

In this case, it is preferable that the MFR (230 DEG C, 2.16 kgf) of the polypropylene resin in the base layer is 1.0 to 15 g / 10 min.

INDUSTRIAL APPLICABILITY The adhesive film according to the present invention exhibits a strong adhesive force to a covering body and can be used for various covering bodies while keeping the adhesive film in a roll state and then the film is partially stretched or deformed even when the film is loosened And it is advantageous in that the processability of the film is excellent.

1 is a schematic view of a measurement sample.

Hereinafter, embodiments of the pressure-sensitive adhesive film of the present invention will be described.

(Substrate layer)

The adhesive film of the present invention requires a substrate layer containing a polypropylene resin as a main component. Examples of the polypropylene resin to be used herein include random copolymers of crystalline polypropylene, propylene and a small amount of alpha -olefin, or block copolymers. More specifically, examples of the crystalline polypropylene resin include n-heptane insoluble isotactic propylene homopolymers used in ordinary extrusion molding or copolymers of propylene and other? -Olefins containing 60% by mass or more of propylene have. The propylene homopolymer or the copolymer of propylene and another? -Olefin may be used alone or in combination.

The base layer preferably contains 60 mass% or more of propylene units, more preferably 70 mass% or more, further preferably 80 mass% or more, particularly preferably 90 mass% or more. If the propylene unit is less than 60% by mass, the film may not have a sense of firmness and may be difficult to handle. When the amount of propylene unit is less than 60% by mass, or when a polyethylene resin is used, the film tends to be flexible and stretched, so that the film tends to partially elongate or deform when the film is unwound.

The n-heptane insolubility indicates the crystallinity of polypropylene and shows safety. In the present invention, n-heptane insolubility (n-heptane insolubility) at 25 ° C for 60 minutes And an eluted fraction of not more than 150 ppm (when the use temperature exceeds 100 캜, not more than 30 ppm)).

Examples of the? -Olefin copolymer component constituting the copolymer of propylene and other? -Olefins include? -Olefins having 2 to 8 carbon atoms such as ethylene or 1-butene, 1-pentene, 1-hexene, And C4 or higher alpha-olefins such as 1-pentene. Here, the copolymer is preferably a random or block copolymer obtained by polymerizing propylene with one or more of the above-mentioned? -Olefins.

Further, the copolymers of propylene and other? -Olefins may be used alone or in combination of two or more.

The melt flow rate (MFR (melt flow rate): 230 DEG C, 2.16 kgf) of the polypropylene resin used is preferably in the range of 1.0 to 15 g / 10 min, more preferably 2.0 to 10.0 g / 10 min.

Further, the debris film produced when the film obtained by the present invention is processed into a product may be reassembled as a raw material for recovery and added to the base layer. By using the recovered raw material, it is possible to suppress the production cost.

(Adhesive layer)

The pressure-sensitive adhesive layer according to the present invention needs to contain a styrene-based elastomer in order to exhibit a high adhesive force. In addition, in order to exhibit adhesive force and film feeding property from the roll state, it is necessary that the adhesive layer includes a polyethylene resin. By adding the polyethylene-based resin, the peeling force from the adhesive surface side to the release surface can be lowered. In addition, a pressure-sensitive adhesive resin, a softening agent, polystyrene, etc. other than a polyethylene resin may be mixed with the pressure-sensitive adhesive layer as necessary for controlling the adhesive force.

The amount of the styrene-based elastomer in the adhesive layer is required to be not less than 35% by mass and not more than 99% by mass with respect to 100% by mass of the adhesive layer component, in order to exhibit high adhesive force and film feedability from the roll state. If it is less than 35% by mass, the adhesive strength is lowered, and it becomes difficult to obtain the necessary adhesive force. The amount of the styrene-based elastomer in the adhesive layer is preferably in the range of 38% by mass or more and 95% by mass or less. And more preferably in the range of 40 mass% or more and 90 mass% or less.

Examples of the styrene elastomer include a hydrogenated product of an ABA type block polymer such as a styrene-butadiene-styrene copolymer, a hydrogenated product of an AB type block polymer such as a styrene-butadiene copolymer, a styrene random copolymer such as styrene-butadiene rubber And the like. The hydrogenated product may be a partially hydrogenated product or a completely hydrogenated product.

The styrene component in the styrene-based elastomer is preferably 5 mass% or more and 40 mass% or less. If it is less than 5% by mass, it becomes difficult to assemble the resin at the time of producing the resin. If it is more than 40% by mass, the adhesive strength is lowered and it becomes difficult to obtain the required adhesive force. The styrene component in the styrene-based elastomer is preferably in the range of 8% by mass or more and 35% by mass or less, more preferably 10% by mass or more and 30% by mass or less.

On the other hand, the ethylene component in the styrene-based elastomer is preferably 15 mass% or more and 70 mass% or less. The ethylene component in the styrene-based elastomer has an effect of improving the compatibility with the polyethylene-based resin, and also has an effect of enhancing the film feedability from the roll state. Therefore, when the amount of ethylene is large, it is considered that the effect of improving the feedability is likely to become large. Further, the ethylene component in the styrene-based elastomer contributes greatly to the manifestation of the adhesive force. If the ethylene component content exceeds 70% by mass, the adhesive strength of the adhesive layer may become excessively high.

Further, it is preferable that a butylene component is present in the styrene-based elastomer. When the content of the butylene component is 50% by mass or more, the addition of the polyethylene-based resin tends to make the adhesive force less likely to deteriorate, which is preferable.

The melt flow rate (MFR: 230 DEG C, 2.16 kgf) of the styrene-based elastomer to be used is preferably in the range of 0.5 to 8 g / 10 min and more preferably in the range of 2.0 to 7.0 g / 10 min in terms of film formability.

The amount of the polyethylene-based resin in the pressure-sensitive adhesive layer is required to be 1% by mass or more and 65% by mass or less in order to exhibit high adhesive force and to exhibit film feedability from the roll state. When the amount of the polyethylene-based resin in the adhesive layer exceeds 65 mass%, the adhesive strength is lowered, and it becomes difficult to obtain the necessary adhesive force. The amount of the polyethylene-based resin in the adhesive layer is preferably in the range of 3% by mass or more and 60% by mass or less.

Examples of the polyethylene-based resin include a low-density polyethylene, a copolymer of ethylene and an? -Olefin, and the like. Of these, low-density polyethylene, in particular, linear low-density polyethylene such as LLDPE and ultra-low-density polyethylene such as VLDPE are preferable because they can improve the feedability of the film while maintaining the adhesive force. These are obtained by copolymerizing an? -Olefin to introduce a short-chain branch into the ethylene chain. Flexibility can be imparted to the polyethylene-based resin by the kind and amount of the? -Olefin.

Examples of the? -olefin include 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene and 1-octene.

In the pressure-sensitive adhesive layer according to the present invention, the sum of the ethylene component and the ethylene-based resin in the styrene-based elastomer is in the range of 35 mass% or more and less than 70 mass% in the adhesive layer component. When the sum of the ethylene component and the ethylene-based resin is 70 mass% or more of the components of the adhesive layer, the adhesive force is lowered and sufficient adhesive force is not obtained. When the sum of the ethylene component and the ethylene-based resin is less than 35% by mass in the adhesive layer component, the peeling strength of the film adhesive layer to the release layer is increased. Preferably, the sum of the ethylene component and the ethylene-based resin is 40 mass% or more and less than 70 mass% in the adhesive layer component. More preferably, the sum of the ethylene component and the ethylene-based resin is 45 mass% or more and 65 mass% or less in the adhesive layer component. Particularly preferably, the sum of the ethylene component and the ethylene-based resin is 45 mass% or more and 63 mass% or less in the adhesive layer component.

The bending modulus of elasticity of the polyethylene-based resin is preferably 10 MPa or more and less than 90 MPa. When the pressure is less than 10 MPa, the film feedability from the roll state is deteriorated. When the pressure is higher than 90 MPa, the pressure-sensitive adhesive layer is hardened, and the adhesive strength tends to decrease. The flexural modulus of the polyethylene-based resin is preferably in the range of 15 MPa to 80 MPa, and more preferably in the range of 20 MPa to 70 MPa.

In order to set the flexural modulus within the above range, it is a policy to adjust the ethylene component in the polyethylene-based resin. From this point of view, the ethylene component in the polyethylene-based resin is preferably 70% by mass or more. The ethylene component of the polyethylene-based resin is more preferably 75% by mass or more, and still more preferably 80% by mass or more. The ethylene content of the polyethylene-based resin is preferably 98% by mass or less, more preferably 96% by mass or less, still more preferably 95% by mass or less, and particularly preferably 94% by mass or less. If the ethylene content in the polyethylene-based resin is less than 70% by mass, the effect of improving film feedability from the roll state tends to be small. Examples of the polyethylene resin having an ethylene content of 70 mass% or more in the polyethylene-based resin include CX3007 and VL100 manufactured by Sumitomo Chemical Co.,

The density of the polyethylene resin is preferably 850 kg / m3 to 920 kg / m3, more preferably 860 kg / m3 to 910 kg / m3, particularly preferably 870 kg / m3 to 908 kg / m3, and most preferably 880 kg / / M 3 to 906 kg / m 3. By setting the above-mentioned range, it is easy to make both the good tackiness and the feedability easy.

The melt flow rate (MFR: 190 DEG C, 2.16 kgf) of the polyethylene-based resin used is preferably in the range of 0.5 g / 10 min to 8 g / 10 min, more preferably 0.8 g / 10 min to 7.0 g / 10 min Do. By setting the thickness to the above range, it is easy to perform film formation with uniform thickness of each layer.

The pressure-sensitive adhesive layer may contain a polyolefin-based resin other than the polyethylene-based resin, and the kind thereof is not particularly limited, and examples thereof include copolymerization of crystalline polypropylene, propylene and a small amount of -olefin. Since this resin generally tends to lower the adhesive force even if it is blended only in a small amount, it is preferable to blend in a proportion of 1% by mass or more and 20% by mass or less.

Examples of the tackifier resin include an aliphatic hydrocarbon resin, an aromatic hydrocarbon resin, a terpene resin, a coumarone-indene resin, a styrene-based resin, and a rosin resin. The molecular weight of the tackifier resin is not particularly limited and can be appropriately set. However, if the molecular weight is reduced, there is a fear that the substance migrates to the cover body from the pressure-sensitive adhesive layer, The improvement effect tends to be insufficient. Therefore, the number average molecular weight of the tackifier resin is preferably about 1,000 to 100,000. The number average molecular weight can be measured by gel permeation chromatography (standard substance: polystyrene) or the like.

The blending amount of the tackifier resin in the adhesive layer is preferably in the range of 5 mass% to 20 mass% with respect to 100 mass% of the adhesive layer component. When the blending amount of the tackifier resin is more than 20% by mass, the tackifier resin has a low molecular weight and therefore has an extremely low melt viscosity, and when co-extrusion coating is carried out using a T-die or the like, And the adhesive layer tends to become sticky, so that the film feedability from the roll state tends to be hard to be improved. If the blending amount of the tackifier resin in the adhesive layer is less than 5% by mass, it is difficult to contribute to the change in the adhesive force of the adhesive layer. Therefore, the blending amount of the tackifier resin is preferably 6 mass% or more and 20 mass% or less. More preferably, it is in the range of 6 mass% or more and 15 mass% or less.

When the melt viscosity tends to decrease by the addition of the tackifier resin to the adhesive layer, the difference in melt viscosity between the base layer and the adhesive layer is improved by adding polystyrene resin to the adhesive layer in an amount of about 1% by mass to 15% , It is easy to laminate. The blending amount of the polystyrene resin is preferably 3 mass% or more and 12 mass% or less, and more preferably 5 mass% or more and 10 mass% or less.

Examples of softeners include low molecular weight diene polymers, polyisobutylene, hydrogenated polyisoprene, hydrogenated polybutadiene and derivatives thereof, polybutene, and the like. The molecular weight of the softening agent is not particularly limited and can be appropriately set. However, if the molecular weight is reduced, there is a possibility that the coating material from the pressure-sensitive adhesive layer will cause material transfer or heavy-weighting. On the other hand, There is a tendency to become scarce. Therefore, the number average molecular weight of the softening agent is preferably about 1,000 to 100,000. The number average molecular weight can be measured by the same method as in the case of the tackifier resin.

The pressure-sensitive adhesive resin or softening agent used for the pressure-sensitive adhesive layer may be a liquid or a powder depending on the kind of the pressure-sensitive adhesive layer, and the extruder may be dirty at the time of extrusion. This problem is solved by using the tackifier resin or softening agent in a master batch with a polyethylene resin or a polyolefin resin. Therefore, it is preferable that the tackifier resin or softening agent is master-batched with a polyethylene-based resin or a polyolefin-based resin.

The adhesive force of the pressure-sensitive adhesive film (pressure-sensitive adhesive layer) of the present invention is preferably in the range of 200 cN / 25 mm to 1000 cN / 25 mm with respect to the acrylic plate at 23 deg. If the adhesive force is less than 200 cN / 25 mm, some of the coated bodies may be handed over when they are protected, and the protective film may not function. On the other hand, when the adhesive force is more than 1000 cN / 25 mm, there is a fear that the film can not be smoothly peeled off from the coated body.

Further, it is preferable to use those having a range of 2 cN / 25 mm to 20 cN / 25 mm with respect to the prism sheet at 23 캜. If the adhesive strength is less than 2 cN / 25 mm, the protective film may fail to be handed over when it is protected. On the other hand, if the adhesive strength is more than 20 cN / 25 mm, there is a fear that the film can not be smoothly peeled off. The adhesive force can be appropriately set by changing the resin composition and thickness of the adhesive layer.

The pressure-sensitive adhesive layer according to the present invention may contain known additives as needed. For example, it may contain a lubricant, an antiblocking agent, a heat stabilizer, an antioxidant, an antistatic agent, an anti-light agent, an impact resistance improver and the like. However, these components are relatively low in molecular weight, and may bleed out on the surface of the pressure-sensitive adhesive layer to lower the adhesive strength of the pressure-sensitive adhesive layer. Therefore, when an additive is used, it is preferable that the amount of low molecular weight substance on the surface of the pressure-sensitive adhesive layer is less than 1 mg / m < 2 >.

The measurement of the low molecular weight substance on the surface of the adhesive layer was carried out in the following procedure. The surface of the pressure-sensitive adhesive layer is washed with an organic solvent which does not corrode the resin constituting the pressure-sensitive adhesive layer such as ethanol, the organic solvent is removed from the cleaning liquid by an evaporator or the like and then the residue is weighed, And the surface area of the surface. If the residues are present at 1 mg / m < 2 > or more, foreign matter is present between the surface of the adhesive layer and the surface of the coating body to decrease the contact area with the coating, thereby lowering the van der Waals force. . In the case of adding an additive, it is necessary to select an additive such as a polymer type, or to examine the addition amount and the addition method so that transition and transfer of the low molecular weight substance (foreign matter) to the adhesive layer are not required.

(Releasing layer)

The adhesive film of the present invention has a release layer opposite to the adhesive layer laminated on one side of the base layer. This makes it possible to suppress the occurrence of blocking between the adhesive films even when the adhesive films are overlapped with each other. By forming the releasing layer, particularly when the adhesive film is stored in a roll state and thereafter the film is loosened, the problem of partial elongation or deformation of the film is unlikely to occur, and a film having excellent processability can be obtained. In order to prevent blocking between the adhesive films even when the adhesive films overlap each other, it is effective to form surface irregularities on the release layer to reduce the contact area with the adhesive layer.

The releasing layer is preferably made of a polypropylene resin as a main component (about 50 mass% or more). Specific examples of the polypropylene resin include a propylene-ethylene block copolymer and the like.

In order to form the surface irregularities on the release layer, it is effective to mix a resin that is incompatible with the polypropylene resin. By doing so, a roughened surface can be formed on the mat. Further, when a propylene-ethylene block copolymer is used as the polypropylene-based resin, the same effect can be expected without using a resin that is nonconductive for the polypropylene-based resin. Naturally, it is also possible to further add a resin that is nonconductive to the polypropylene resin to the propylene-ethylene block copolymer.

As the resin for use in the polypropylene type resin, an α-olefin (co) polymer having 4 or more carbon atoms such as low density polyethylene and 4-methylpentene-1 system (co) polymer is suitably used. In addition, examples thereof include linear low-density polyethylene, high-density polyethylene, copolymers of ethylene and a small amount of -olefins, copolymers of ethylene and vinyl acetate, polystyrene, polyester resins and polyamide resins. In particular, in the case of using a 4-methylpentene-1 system (co) polymer, not only the surface of the release layer is roughened in the form of a matte but also the surface free energy of the surface of the film is lowered to further improve the peeling property .

In consideration of the resin composition of the adhesive layer of the present invention, it is preferable that the three-dimensional average surface roughness SRa of the surface of the release layer is 0.10 m or more and 0.50 m or less. By doing so, it is possible to improve the blocking resistance and the protection performance of the cover body. If the surface roughness of the release layer is lower than 0.10 占 퐉, the film feedability when the film is made into a roll form may be deteriorated. When the surface roughness of the release layer is higher than 0.50 占 퐉, the surface irregularities of the release layer are transferred to the surface of the pressure-sensitive adhesive layer, and the adhesive strength is remarkably lowered. At this time, it is more preferable that the surface irregularities of the release layer have a surface with an average surface roughness SRa of not less than 0.25 mu m and not more than 0.45 mu m.

In addition, the three-dimensional average surface roughness SRa of the surface of the release layer means an average roughness at the center surface when the surface roughness curve is approximated by a sine curve, and can be measured by a surface roughness measuring device or the like.

(Self-adhesive surface protective film)

The self-adhesive surface protective film of the present invention is composed of each layer of a base layer, an adhesive layer, and a release layer containing the resin component. The thickness of the self-adhesive surface protection film of the present invention is preferably from 10 탆 to 150 탆, more preferably from 15 탆 to 120 탆, and further preferably from 20 탆 to 100 탆. If the total thickness of the film is too thin, the handling property may be poor. If the film thickness is excessively large, the rigidity is increased and the handling property is deteriorated. In addition, the film may be disadvantageous in terms of cost.

The thickness of the base layer of the present invention is preferably 5 mu m or more and less than 100 mu m, more preferably 10 mu m or more and 75 mu m or less, still more preferably 15 mu m or more and 55 mu m or less. When the thickness of the base layer is less than 5 탆, the elasticity is weakened. As a protective film, wrinkles or the like easily occur when the film is adhered to the cover, resulting in insufficient adhesion.

The thickness of the pressure-sensitive adhesive layer of the present invention is preferably 1 m or more and less than 30 m. If the thickness of the adhesive layer is less than 1 m, stable film formation by coextrusion becomes difficult, and if it is 30 m or more, the film becomes disadvantageous in terms of cost. At this time, when the adhesive strength is increased, it is preferable to increase the thickness of the adhesive layer in consideration of the viscosity. By increasing the thickness of the adhesive layer, the area of contact with the covering body tends to become large. The thickness of the adhesive layer is preferably 2 탆 or more and 20 탆 or less, more preferably 3 탆 or more and 15 탆 or less, and particularly preferably 4 탆 or more and 8 탆 or less.

The thickness of the release layer of the present invention is preferably 1 mu m or more and less than 30 mu m. If the thickness of the release layer is less than 1 mu m, stable film formation by coextrusion becomes difficult, and if it is 30 mu m or more, the film becomes disadvantageous in terms of cost. The thickness of the release layer is preferably 2 탆 or more and 20 탆 or less, more preferably 3 탆 or more and 15 탆 or less.

The peel force of the adhesive film of the present application on the adhesive surface releasing face is preferably 250 cN / 40 mm or less at 23 캜, from the viewpoint of film feedability when the adhesive film is in roll form. If the peeling force exceeds 250 cN / 40 mm, there arises a problem that the film is partially elongated or deformed when the adhesive film is rolled. More preferably 200 cN / 40 mm or less. Further, the lower limit of the peeling force of the adhesive surface of the adhesive film on the release surface is about 1 cN / 40 mm, more preferably about 5 cN / 40 mm.

The self-adhesive surface protective film of the present invention is composed of the respective layers of the base layer, the adhesive layer and the release layer including the resin component, and the resin constituting each layer is, for example, a single shaft, And fed to a T-die of a feed block type or a multi-manifold type in a molten state and laminated and extruded in three or more layers (base layer, adhesive layer, release layer) or more. The temperature of the extruder in each layer may be appropriately adjusted in consideration of the molding temperature of the component used in each layer appropriately in order to make each layer into a molten state, and may be adjusted within a range of, for example, 200 캜 to 260 캜. The temperature of the T die may be the same as the above temperature. The picking speed from the T die to the casting roll may be any speed that allows each layer to have a suitable thickness, for example from 10 m / min to 200 m / min, preferably from 10 m / min to 100 m / min.

The adhesive film of the present invention is suitable for handling in the form of a roll. Although the upper limit of the width and the winding length of the film roll is not particularly limited, it is preferable that the width is not more than 1.5 m and the winding length is not more than 5000 m in the case of the film thickness of 40 m. As the winding core, plastic cores or metal cores, typically 3 inches, 6 inches, 8 inches, etc., can be used. Further, it is preferable that the film roll is wound in a dimension of 200 m or more in length and 450 mm in width or more from the viewpoint of workability.

The pressure-sensitive adhesive film of the present invention can be applied to a variety of applications such as a member such as a prism sheet used for optical applications, a synthetic resin plate (for building material), a stainless steel plate (for building material, for example) In order to protect the surfaces of glass plates, appliances, precision machinery and automobile bodies at the time of manufacture, to protect against the occurrence of scratches during lamination, storage, transport or transport in the manufacturing process, (For example, a bending process or a press process).

This application claims the benefit of priority based on Japanese Patent Application No. 2012-89184 filed on April 10, 2012. The entire contents of the specification of Japanese Patent Application No. 2012-89184 filed on April 10, 2012 are hereby incorporated by reference herein.

Example

Hereinafter, the present invention will be described with reference to examples. However, the present invention is not limited to the following examples unless they depart from the gist of the present invention. In the following Examples and Comparative Examples, evaluation methods of physical properties are as follows.

(1) Evaluation of stickiness

According to JIS-Z-0237 (2000) Test method for adhesive tape and pressure-sensitive adhesive sheet, the following methods were used.

(3 mm thickness, manufactured by Mitsubishi Rayon Co., Ltd.) of 50 mm x 150 mm and a prism sheet (including a triangular prism in the lens portion, the height of the triangular prism being 25 mu m, And the width of the prism was 50 mu m). As test pieces, test pieces having a size of 150 mm in the take-up direction and 25 mm in the direction perpendicular to the take-up direction were cut out.

A test piece was applied to the test piece at a rate of 5 mm / minute using a 2000 g mass rubber roll (having a roller hardness of 80 Hs and a rubber layer of 6 mm in thickness, 45 mm in width and 95 mm in diameter (including rubber layer) Lt; RTI ID = 0.0 > sec. ≪ / RTI > After compression, the sample was allowed to stand for 30 minutes under an environment of a temperature of 23 DEG C and a relative humidity of 65%, and the sample was measured at a speed of 300 mm / minute using AGOG-J (Shimazu Seisakusho Co., And the resistance value when the film was peeled off by 180 degrees was regarded as an adhesive force [cN / 25 mm]. 180 deg. Peeling means maintaining the peeling angle of the acrylic plate and the film at 180 degrees when measuring the resistance value at the time of peeling.

At the time of measurement, a polyester sheet having a thickness of 190 탆 and a size of 25 mm × 170 mm was prepared as a gripping portion of the test sample. The test piece and the acrylic plate were pressed together, , The polyester sheet was attached by a cellophane tape to serve as a grip portion at the time of measurement. A schematic diagram of the measurement sample is shown in Fig. The measurement was carried out on three samples prepared from the respective films produced in Examples and Comparative Examples, and the average value thereof was regarded as the adhesive strength of the sample. In the case of the prism sheet, measurement was carried out in the same manner.

(2) Evaluation of peel strength

A double-faced adhesive tape (manufactured by Nitto Denko Corporation) was attached to the entire surface of an acrylic plate (acrylic light (registered trademark) made by Mitsubishi Rayon Co., Ltd., 3 mm thick) 50 mm x 150 mm, (Direction of winding at the time of film production) x 50 mm (direction perpendicular to the winding direction at the time of film production) so that the adhered surface of the test piece was located.

As a new test piece, a test piece having a length of 150 mm in the take-up direction and a length of 40 mm in the direction perpendicular to the take-up direction was cut out and the test piece adhered to the adhesive surface and the acrylic plate through a double- After the releasing surfaces were superimposed, a rubber roll having a mass of 2000 g (having a spring hardness of 80 Hs and a rubber layer of 6 mm in thickness, having a width of 45 mm and a diameter of 95 mm including a rubber layer) And the test piece was subjected to one round trip at a speed of 5 mm / sec. After compression, a load of 60 kg was applied to a total area of 4000 mm 2, which is 100 mm in the winding direction and 40 mm in the direction orthogonal to the winding direction, and left to stand at an ambient temperature of 40 캜 and a relative humidity of 65% for 24 hours. Resistance value at the time of 180 degrees peeling at a speed of 300 mm / min by using "Autograph (registered trademark)" (AGS-J) manufactured by Shimadzu Seisakusho Co., Ltd. was measured as peeling force [cN / ].

At the time of measurement, a polyester sheet having a thickness of 190 mu m and a size of 40 mm x 170 mm was prepared as a gripping portion of the measurement specimen and attached to the end of a test piece of 150 mm x 40 mm with a cellophane tape And was used as a grip portion at the time of measurement. The measurement was carried out three times with respect to one sample, and the average value thereof was taken as the peeling force of the sample.

(3) Feedability from a roll

A 550 mm wide and 500 m rolled winding was obtained by slitting and then stored in a roll state for 7 days under a light shielding condition of a temperature of 23 캜 and a humidity of 75%. Immediately after rewinding the film roll after storage for 300 m to another plastic core (diameter 9 cm), the end of the film was gripped by hand, pulled, and rewound for 3 m. Upon rewinding, the film was visually inspected for partial elongation or deformation. (Good), and those with partial elongation or deformation were evaluated as x (poor).

(4) MFR measurement of resin

Measurement was carried out in accordance with JIS-K7210.

(5) Measurement of bending elastic modulus of resin

Measurement was carried out in accordance with ASTM D747-70.

(6) Measurement of ethylene component in styrene elastomer

Approximately 330 mg of the resin sample was dissolved in deuterated chloroform and measured by ¹³ C-NMR (AVANCE 500, manufactured by BRUKER). From the obtained measurement results, the amount of ethylene component in the styrene-based elastomer was identified.

[Example 1]

(Preparation of base layer)

100% by mass of a homopolypropylene resin (FLX80E4, manufactured by Sumitomo Chemical Co., Ltd., MFR: 230 DEG C MFR: 10 minutes) was melt-extruded at 240 DEG C by a 90 mm phi single screw extruder to obtain a substrate layer.

(Production of adhesive layer)

A styrene-based elastomer (a hydrogenated product of a block copolymer of styrene and butadiene, available from Asahi Gas Chemical Co., Ltd.: TUPTEC (registered trademark) H1221, styrene component ratio of 12 mass%, ethylene component ratio of 18 mass%, 230 占 폚 MFR: 4.5 g / , 50 mass% of an ethylene-? Olefin copolymer (CX3007, 190 占 폚 MFR: 3.7 g / 10 min, modulus of elasticity: 26 MPa) and 40 mass% of a petroleum resin (ARAKAWA CHEMICAL Co., Trade name P125) was melt-extruded at 210 占 폚 by a 45 mm? Single screw extruder to obtain an adhesive layer.

(Preparation of release layer)

90% by mass of a propylene-ethylene block copolymer (manufactured by Nippon Polypropylene: BC3HF) and 10% by mass of a low-density polyethylene resin (Ube Gosan: R300) were melt-extruded at 230 占 폚 by a 65 mm? Single screw extruder to obtain a release layer.

(Production of film)

Layer extrusion was carried out in a three-layer T die (feed block type, lip width 850 mm, lip gap 1 mm) at 245 캜 with the substrate layer, the adhesive layer and the release layer being melted by the respective extruders. The extruded film was drawn into a casting roll at a temperature of 30 캜 at a speed of 20 m / min and cooled and solidified to obtain a film having a base layer thickness of 28 탆, a pressure-sensitive adhesive layer thickness of 6 탆, a release layer thickness of 6 탆, 3-layer undrawn film having a length of 1100 m was obtained. Further, this film was slit at a speed of 50 m / min while applying a 50 N contact pressure to the film width with a pulling tension of 40 N by a rubber roll to obtain an unstretched film having a film width of 550 mm and a film length of 500 m.

[Example 2]

The base layer and the release layer were changed to the following contents in the state of Example 1, and the same processes as in Example 1 were carried out to obtain three kinds of three-layer unoriented films.

(Production of adhesive layer)

60% by mass of a styrene-based elastomer (Asahi Gas Chemical Co., Ltd.: TUPTEC (registered trademark) H1221, styrene component ratio of 12 mass%, ethylene component ratio of 18 mass%, 230 占 폚 MFR: 4.5 g / 10 min) 40% by mass was melt-extruded at 210 占 폚 by a 45 mm? Single-screw extruder to obtain a pressure-sensitive adhesive layer.

[Example 3]

The base layer and the release layer were changed to the following contents in the state of Example 1, and the same processes as in Example 1 were carried out to obtain three kinds of three-layer unoriented films.

(Production of adhesive layer)

A styrene-based elastomer (a hydrogenated product of a block copolymer of styrene and butadiene, available from Asahi Gas Chemical Co., Ltd.: TUPTEC (registered trademark) H1221, styrene component ratio of 12 mass%, ethylene component ratio of 18 mass%, 230 占 폚 MFR: 4.5 g / And 50% by mass of an ethylene-? Olefin copolymer (VL100 manufactured by Sumitomo Chemical Co., Ltd., MFR: 0.8 g / 10 min at 190 占 폚, elastic modulus: 64 MPa) and a petroleum resin (Arakawa Chemical Industries, (Trademark) P125) was melt-extruded at 210 占 폚 by a 40 mm? Single screw extruder to obtain an adhesive layer.

[Example 4]

The base layer and the release layer were changed to the following contents in the state of Example 1, and the same processes as in Example 1 were carried out to obtain three kinds of three-layer unoriented films.

(Production of adhesive layer)

85% by mass of a styrene-based elastomer (Asahi Gas Chemical Co., Ltd.: TUPTEC (registered trademark) H1041, styrene component ratio 30 mass%, ethylene component ratio 49 mass%, 230 占 폚 MFR: 5.0 g / 10 min) , 10 mass% of a petroleum resin (Alcon (registered trademark) P125) by 5 mass% and a 10 mass% of a petroleum resin (Arakawa Chemical Industries, Ltd., CX3007, 190 占 폚 MFR: 0.8 g / 10 min, Extruded at 210 캜 by an extruder to obtain an adhesive layer.

[Example 5]

The base layer and the release layer were prepared in the same manner as in Example 1 except that the pressure-sensitive adhesive layer was changed to the following contents and the base layer thickness was 26 탆, the pressure-sensitive adhesive layer thickness was 8 탆 and the release layer thickness was 6 탆 A three-kind three-layer unoriented film was obtained in the same manner as in 1.

(Production of adhesive layer)

60% by mass of a styrene-based elastomer (Asahi Gas Chemical Co., Ltd.: TUPTEC (registered trademark) H1221, styrene component ratio of 12 mass%, ethylene component ratio of 18 mass%, 230 占 폚 MFR: 4.5 g / 10 min) 40% by mass was melt-extruded at 210 占 폚 by a 45 mm? Single-screw extruder to obtain a pressure-sensitive adhesive layer.

[Example 6]

The base layer and the release layer were prepared in the same manner as in Example 1 except that the pressure-sensitive adhesive layer was changed to the following contents and the base layer thickness was 30 占 퐉, the pressure-sensitive adhesive layer thickness was 4 占 퐉 and the release layer thickness was 6 占 퐉 A three-kind three-layer unoriented film was obtained in the same manner as in 1.

(Production of adhesive layer)

40% by mass of a styrene-based elastomer (Asahi Gas Chemical Co., Ltd.: TUPTEC (registered trademark) H1221, styrene component ratio of 12 mass%, ethylene component ratio of 18 mass%, 230 占 폚 MFR: 4.5 g / 10 min) 55 mass% of a petroleum resin (Alcon (registered trademark) P125 manufactured by Arakawa Chemical Industry Co., Ltd.) 5 mass% was shortened by 45 mm Extruded at 210 캜 by an extruder to obtain an adhesive layer.

[Comparative Example 1]

The base layer and the release layer were changed to the following contents in the state of Example 1, and the same processes as in Example 1 were carried out to obtain three kinds of three-layer unoriented films.

(Production of adhesive layer)

70% by mass of a styrene-based elastomer (Asahi Gas Chemical Co., Ltd.: TUPTEC (registered trademark) H1221, styrene component ratio of 12 mass%, ethylene component ratio of 18 mass%, 230 占 폚 MFR: 4.5 g / 10 min) (Alcon (registered trademark) P125) of 20% by mass and a petroleum resin (Alcon (registered trademark) P125) in an amount of 10% by mass were shortened by 40 mm in diameter (CX3007 manufactured by Sumitomo Chemical Co., Ltd., 190 占 폚 MFR: 3.7 g / 10 min, Extruded at 210 캜 by an extruder to obtain an adhesive layer.

[Comparative Example 2]

The base layer and the release layer were changed to the following contents in the state of Example 1, and the same processes as in Example 1 were carried out to obtain three kinds of three-layer unoriented films.

(Production of adhesive layer)

70% by mass of a styrene-based elastomer (Asahi Gas Chemical Co., Ltd.: TUPTEC (registered trademark) H1221, styrene component ratio of 12 mass%, ethylene component ratio of 18 mass%, 230 占 폚 MFR: 4.5 g / 10 min) (Alcon (registered trademark) P125) of 20% by mass and 20% by mass of a petroleum resin (Alcon (registered trademark) P125) at a temperature of 190 占 폚 for a MFR of 0.8 g / 10 min and an elastic modulus of 64 MPa) Extruded at 210 캜 by an extruder to obtain an adhesive layer.

[Comparative Example 3]

20% by mass of a styrene-based elastomer (Asahi Gas Chemical Co., Ltd.: TUPTEC (registered trademark) H1221, styrene component ratio of 12 mass%, ethylene component ratio of 18 mass%, 230 占 폚 MFR: 4.5 g / 10 min) 70% by mass) and 10% by mass of a petroleum resin (Alcon (registered trademark) P125) of 40% by mass were shortened by 40 mm phi (manufactured by Sumitomo Chemical Co., Ltd., CX3007, 190 占 폚 MFR: 3.7 g / 10 min, Extruded at 210 캜 by an extruder to obtain an adhesive layer.

[Comparative Example 4]

The base layer and the release layer were changed to the following contents in the state of Example 1, and the same processes as in Example 1 were carried out to obtain three kinds of three-layer unoriented films.

(Production of adhesive layer)

40% by mass of a styrene-based elastomer (Asahi Gas Chemical Co., Ltd.: TUPTEC (registered trademark) H1221, styrene component ratio of 12 mass%, ethylene component ratio of 18 mass%, 230 占 폚 MFR: 4.5 g / 10 min) and homopolypropylene 10% by mass of a petroleum resin (Arakawa Chemical Industry Co., Ltd .: Alcon (registered trademark) P125) was melted at 210 占 폚 by a 40 mm? Single screw extruder at a temperature of 210 占 폚 And extruded to form an adhesive layer.

The results are shown in Tables 1 and 2.

As apparent from Table 2, the films obtained in Examples 1 to 6 had sufficient adhesive force for practical use when used as a protective film, and had good peelability when the film was unwound from the roll.

On the other hand, the films obtained in Comparative Examples 1 and 2 were not always satisfactory in peelability when the film was unwound from a roll. The films obtained in Comparative Examples 3 and 4 could not be said to have sufficient adhesion to the cover. All of the films obtained in this Comparative Example were inferior in quality and practically inferior.

Claims (5)

An adhesive layer is laminated on one side of a substrate layer containing a polypropylene resin and a release layer is formed on the opposite side by coextrusion,
Wherein the release layer comprises a polypropylene resin and at least one selected from low-density polyethylene, an? -Olefin polymer having 4 or more carbon atoms and an? -Olefin copolymer having 4 or more carbon atoms,
Wherein the resin constituting the adhesive layer comprises at least a styrene elastomer and a polyethylene resin,
Wherein the styrene-based elastomer is a hydrogenated product of a block copolymer having a styrene-based polymer block and a butadiene-based polymer block, or a hydrogenated product of a block copolymer having a styrene-based polymer block and a random copolymer block of styrene and butadiene, Wherein the polyethylene-based resin is an ethylene homopolymer and / or an ethylene-alpha olefin copolymer,
The content of the styrene-based elastomer in the adhesive layer is 35 mass% or more and 99 mass% or less, the content of the polyethylene resin is 1 mass% or more and 65 mass%
Wherein the sum of an ethylene component and a polyethylene-based resin in the styrene-based elastomer is 50.8% by mass or more and less than 70% by mass in the adhesive layer component,
Wherein the ethylene component in the polyethylene-based resin is 70 mass% or more and 98 mass% or less. The self-adhesive surface protective film according to claim 1, wherein the polyethylene resin used for the adhesive layer has a flexural modulus of 10 MPa or more and less than 90 MPa. The self-adhesive surface protective film according to claim 1 or 2, wherein the polyethylene resin in the adhesive layer has a melt flow rate (190 占 폚, 2.16 kgf) of 0.5 to 8 g / 10 minutes. The self-adhesive surface protective film according to any one of claims 1 to 3, wherein the styrene-based elastomer in the adhesive layer has an MFR (230 占 폚, 2.16 kgf) of 0.5 to 8 g / 10 minutes. The self-adhesive surface protective film according to claim 1 or 2, wherein the MFR (230 占 폚, 2.16 kgf) of the polypropylene resin in the base layer is 1.0 to 15 g / 10 minutes.

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