TW201402760A - Self-adhesive surface protection film - Google Patents

Abstract

The object of the present invention is to provide a self-adhesive protection film which performs strong adhesive to a coated body, can be used for each kinds of coated body, and without causing defects such as make the film to be partially elongated, deformed even when the adhesive film is retained in a rolling condition to draw the film, and has excellent processing suitability. The self-adhesive surface protection film is laminated by coextruding an adhesive layer on one face of substrate layer formed from a polypropylene-based resin, and coextruding a mold release layer on a reverse face, and the resin used for forming the adhesive layer at least includes a styrene-based elastomer and a polyethylene-based resin. The styrene-based elastomer comprises a hydride of block copolymer including a styrene-based polymer block and a butadiene-based polymer block, or a hydride of block copolymer including a styrene-based polymer block and a random polymer block of styrene and butadiene. The polyethylene-based resin comprises an ethylene homopolymer and/or an ethylene- α olefin copolymer. In the adhesive layer, the content of styrene-based elastomer is not less than 35 mass% and not more than 99 mass%, the content of the polyethylene-based resin is not less than 1 mass% and not more than 65 mass%, and the sum of the ethylene content of the polyethylene-based resin and the styrene-based elastomer is 35 mass% or more and less than 70 mass% in the content of adhesive layer.

Description

Self-adhesive surface protection film

The present invention relates to an adhesive film. The adhesive film of the present invention is used for protecting members such as ruthenium used for optical applications, synthetic resin sheets (for example, for building materials), stainless steel sheets (for building materials), aluminum sheets, decorative plywood, steel sheets, glass sheets, and home appliances. Products, precision machinery, and the surface of the car body during manufacture can be used to protect against scratches during stacking, storage, transportation, and manufacturing steps, as well as protection from secondary processing of articles. Scratch in the case of (for example, bending or press working).

In the past, the adhesive film for the purpose of protecting the surface of the covering was used for processing, storage, and transportation of building materials, electrical, electronic products, automobiles, etc., and the adhesive film must have good adhesion and after use. So that the surfaces are not contaminated by the adhesive and are easy to tear off.

The diversity of the above-mentioned coverings has also progressed in recent years, and it is not only a smooth surface of the covering but also many surface irregularities. The covering body having the surface unevenness may, for example, be a prism type lens portion used for a cymbal of an optical member. In order to exhibit a sufficient adhesion to a covering having a surface unevenness such as a cymbal, it is considered that the adhesion of the adhesive layer is increased to make the contact area small. Can also have adhesion.

In order to improve the adhesion of the adhesive layer, a resin containing a styrene-based elastomer having a high adhesive strength as a main component can be used. However, if the adhesive force of the adhesive layer is increased, the film is stored in a roll state, and then the film is taken out. At the time, there is a problem that problems such as local elongation and deformation of the film occur.

In the above-mentioned problem, a fluorine-based resin, a ruthenium-oxygen resin (for example, see Patent Document 1), an ultra-high molecular polydimethyl siloxane (for example, see Patent Document 2), or In the case of research on saturated fatty acid biguanide (for example, refer to Patent Document 3), it is possible to move the resin to the adhesive layer when it is stored in a roll state, and it is impossible to remove the problem of lowering the adhesive force and contaminating the covering.

In addition, it has been studied to add a polyethylene-based resin to the adhesive layer (for example, refer to Patent Document 4, Patent Document 5, etc.), but it is impossible to satisfy the adhesion to the prism, and to store the film in a roll state, and then take out the film. The above problems in the film.

[Previous Technical Literature] [Patent Document]

Patent Document 1 Japanese Patent Laid-Open Publication No. 2008-81589

Patent Document 2 Japanese Patent Laid-Open Publication No. 2008-308559

Patent Document 3 Japanese Patent No. 4565058

Patent Document 4 Japanese Patent Publication No. 08-73822

Patent Document 5 Japanese Patent Laid-Open Publication No. 2007-161882

The problem to be solved by the present invention is to provide a self-adhesive surface protective film which exhibits a strong adhesive force to a covering body, can be used for various covering bodies, and at the same time, when the adhesive film is stored in a rolled state, and then the film is taken out, the film is obtained. It is also less prone to problems such as local elongation and deformation, and the film has excellent processing suitability.

As a result of the research by the inventors of the present invention, it has been found that the above problems can be solved by setting the type and ratio of the resin used in the adhesive layer to a specific range, and the present invention has been achieved.

That is, the present invention relates to a self-adhesive surface protective film characterized in that it is a coextruded adhesive layer on one side of a base material layer composed of a polypropylene-based resin, and a release layer is coextruded on the opposite side. The resin constituting the adhesive layer contains at least a styrene-based elastomer and a polyethylene-based resin, and the styrene-based elastic system has a styrene-based polymer block and a butadiene-based polymer block. a hydride of a segment copolymer, or a hydride of a block copolymer having a styrene polymer block and a random copolymer block of styrene and butadiene, the polyethylene resin being ethylene homopolymerized And the content of the styrene-based elastomer in the adhesive layer is 35 mass% or more and 99 mass% or less, and the content of the polyethylene resin is 1 mass% or more and 65 mass% or less. And the sum of the ethylene component and the polyethylene resin in the styrene elastomer The adhesive layer component is 35 mass% or more and less than 70 mass%.

According to the present invention, it is possible to obtain a strong adhesive force to the covering body, which can be used for When the adhesive film is stored in a roll state and the film is taken out, the film is also less likely to cause local elongation and deformation, and the film is excellent in self-adhesive surface protective film.

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

Moreover, in this case, the MFR (190 ° C, 2.16 kgf) of the polyethylene resin in the adhesive layer is preferably 0.5 to 8 g/10 min.

Further, in this case, the MFR (230 ° C, 2.16 kgf) of the styrene-based elastomer in the adhesive layer is preferably 0.5 to 8 g/10 min.

Further, in this case, the MFR (230 ° C, 2.16 kgf) of the polypropylene resin in the base material layer is preferably 1.0 to 15 g/10 min.

The adhesive film of the present invention has a strong adhesive force to the covering, can be used for various coverings, and when the adhesive film is stored in a roll state, and then the film is taken out, the film is less likely to locally elongate and deform, and the film is not affected. Excellent processing and other advantages.

Figure 1 is a schematic view of a measurement sample.

[Formation of the Invention]

Hereinafter, an embodiment of the adhesive film of the present invention will be described.

(base material layer)

The adhesive film of the present invention must be mainly composed of a polypropylene resin. Substrate layer. The polypropylene-based resin used herein may be a crystalline polypropylene, a random copolymer of propylene and a small amount of an α-olefin, or a block copolymer. More specifically, the crystalline polypropylene resin may be an n-heptane-insoluble homopolymer propylene homopolymer used in usual extrusion molding or the like, or propylene and other α-olefins containing 60% by mass or more of propylene. Copolymer. The propylene homopolymer or a copolymer of propylene and other α-olefins may be used singly or in combination.

The base material layer preferably contains 60% by mass or more of propylene unit, more preferably 70% by mass or more, still more preferably 80% by mass or more, and particularly preferably 90% by mass or more. When the amount of the propylene unit is less than 60% by mass, the film may feel no rigidity and it may become difficult to use. Further, when the amount of the propylene unit is less than 60% by mass, when the polyethylene-based resin is used, the film is soft and can be easily stretched, and when the film is taken out, the film is liable to cause local elongation and deformation.

Here, the n-heptane insoluble type is used as an indicator of the crystallinity of polypropylene, and it also shows safety. In the present invention, it is preferable to use n-heptane insoluble (25 ° C, extraction according to No. 20 of the Ministry of Health and Welfare, February, Showa 57). The eluted portion at 60 minutes was 150 ppm or less [using a temperature of more than 100 ° C and 30 ppm or less].

Examples of the α-olefin copolymer component constituting the copolymer of propylene and another α-olefin include an α-olefin having 2 to 8 carbon atoms, for example, ethylene or 1-butene, 1-pentene, 1-hexene, An α-olefin having a C4 or higher such as 4-methyl-1-pentene. Here, the copolymer is preferably a random or block copolymer obtained by polymerizing one or more of the above α-olefins to propylene.

In addition, the copolymer of propylene and other α-olefins may be used alone or in combination of two. Mix on top.

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

Further, the chip film produced during the processing of the film obtained by the present invention can be regranulated as a raw material for recycling, and added to the substrate layer. By using recycled raw materials, production costs can be suppressed.

(adhesive layer)

The adhesive layer of the present invention must contain a styrene-based elastomer in order to exhibit high adhesion. Further, in order to exhibit the adhesive force and the extraction property of the film from the wound state, the adhesive layer must contain a polyethylene resin. By adding a polyethylene-based resin, the peeling force of the adhesive surface side to the release surface can be reduced. In addition, in order to control the adhesive force, an adhesive imparting resin other than the polyethylene resin, a softener, polystyrene, or the like may be mixed in the adhesive layer as needed.

The amount of the styrene-based elastomer in the adhesive layer is required to exhibit a high adhesive force and to exhibit a drawability of the film in a self-rolling state, and it is necessary to have 35 mass% or more and 99 mass% or less with respect to 100% by mass of the adhesive layer component. . If it is less than 35% by mass, the adhesive force is lowered, and it is difficult to obtain a 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. More preferably, it is 40 mass % or more and 90 mass % or less.

Examples of the styrene-based elastomer include a hydrogenated product of an ABA-type block polymer such as a styrene-butadiene-styrene copolymer, and a hydrogenated product of an AB-type block polymer such as a styrene-butadiene copolymer. Styrene-butadiene rubber A hydride or the like of an olefinic random copolymer. Among them, their hydrides may be partial hydrides or complete hydrides.

The styrene component in the styrene-based elastomer is desirably 5% by mass or more and 40% by mass or less. When it is less than 5% by mass, granulation during production of the resin is difficult, and if it is more than 40% by mass, the adhesion is lowered, and it is difficult to obtain a necessary adhesive force. In particular, the styrene component in the styrene elastomer is preferably in the range of 8% by mass or more and 35% by mass or less, more preferably in the range of 10% by mass or more and 30% by mass or less.

On the other hand, the ethylene component in the styrene-based elastomer is desirably 15% by mass or more and 70% by mass or less. The ethylene component in the styrene-based elastomer has an effect of improving the compatibility with the polyethylene-based resin, and has an effect of improving the extractability of the film from the wound state. Therefore, it is considered that when the amount of the ethylene component is large, the effect of improving the extractability is likely to be improved. Among them, the ethylene component in the styrene-based elastomer is also considered to contribute greatly to exhibiting adhesion, and if the amount of the ethylene component is more than 70% by mass, the adhesive strength of the adhesive layer may become excessively high.

Further, a butene component is preferably present in the styrene elastomer. When the amount of the butene component is 50% by mass or more, when the polyethylene resin is added, the adhesion tends not to be lowered, which is preferable.

The melt flow rate (MFR: 230 ° 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, more preferably 2.0 to 7.0 g in terms of film formability. 10 minutes range.

The amount of polyethylene resin in the adhesive layer is to show high adhesion and display The extraction property of the film from the roll state must be 1% by mass or more and 65% by mass or less. When the amount of the polyethylene-based resin in the adhesive layer is more than 65 mass%, the adhesive force is lowered, and it is difficult to obtain a necessary adhesive force. The amount of the polyethylene-based resin in the adhesive layer is preferably in the range of 3% by mass to 60% by mass.

Examples of the polyethylene resin include low density polyethylene, a copolymer of ethylene and an α-olefin, and the like. Among them, low-density polyethylene, especially linear low-density polyethylene called LLDPE, and ultra-low-density polyethylene called VLDPE are preferred because they can maintain adhesion and improve film extraction. of. This is a method in which a short-chain branch is introduced into an ethylene chain by copolymerization with an α-olefin, and the flexibility and impartability of the polyethylene-based resin can be imparted by the type and copolymerization amount of the α-olefin.

The α-olefin may, for example, be 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene or 1-octene.

In the adhesive layer of the present invention, the sum of the ethylene component and the ethylene resin in the styrene 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 resin accounts for 70% by mass or more of the adhesive layer component, the adhesive force is lowered, and sufficient adhesive force cannot be obtained. On the other hand, when the sum of the ethylene component and the ethylene resin is less than 35% by mass in the adhesive layer component, the peeling force against the release layer of the film adhesive layer becomes high. The sum of the ethylene component and the ethylene resin is preferably 40% by mass or more and less than 70% by mass in the adhesive layer component. More preferably, the sum of the ethylene component and the ethylene resin is 45 mass% or more and 65 mass% or less in the adhesive layer component. It is particularly preferable that the sum of the ethylene component and the ethylene resin is 45 mass% or more and 63 mass% or less in the adhesive layer component.

The bending modulus of the polyethylene resin is desirably 10 MPa or more and less than 90 MPa. When the thickness is less than 10 MPa, the extraction property of the film from the wound state is lowered, and when it is 90 MPa or more, the adhesive layer is hardened and the adhesive strength tends to be lowered. The flexural modulus of the polyethylene resin is preferably in the range of 15 MPa to 80 MPa, more preferably in the range of 20 MPa to 70 MPa.

In order to make the bending modulus within the above range, it is one of the methods to adjust the ethylene component in the polyethylene resin. From this point of view, the ethylene component in the polyethylene resin is preferably 70% by mass or more. The ethylene component of the polyethylene resin is more preferably 75% by mass or more, still more preferably 80% by mass or more. Further, the content of ethylene in the polyethylene 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. When the ethylene component in the polyethylene resin is less than 70% by mass, the effect of improving the extraction property of the film from the wound state tends to be small. An example of the polyethylene resin having a vinyl component of 70% by mass or more in the polyethylene resin is CX3007 or VL100 manufactured by Sumitomo Chemical Co., Ltd., and the like.

Density polyethylene-based resin is preferably ^{850kg / m 3 ~ 920kg / m} 3, more preferably from ^{860kg / m 3 ~ 910kg / m} 3, particularly preferably ^{870kg / m 3 ~ 908kg / m} 3, most preferably 880kg / m ³ ~ 906kg/m ³ . By the above range, it is possible to easily achieve both good adhesion and extractability.

The melt flow rate (MFR: 190 ° C, 2.16 kgf) of the polyethylene-based resin to be 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. The scope. By the above range, it becomes easy to form a film having a uniform thickness of each layer.

The adhesive layer may be a polyolefin-based resin other than the polyethylene-based resin, and the type thereof is not particularly limited, and examples thereof include a crystalline polypropylene, a copolymer of propylene and a small amount of an α-olefin, and the like. These resins tend to have a tendency to easily lower the adhesion because they are generally blended in a small amount, and therefore are preferably formulated in a ratio 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 benzofuran/indene resin, a styrene resin, and a rosin resin. The molecular weight of the adhesiveness-imparting resin is not particularly limited, and may be appropriately set. However, if the molecular weight is small, the substance may move from the adhesive layer to the coating or the peeling force may increase. On the other hand, the molecular weight may become large. There is a tendency that the effect of the improvement of the force is insufficient. Therefore, the number average molecular weight of the adhesive imparting resin is preferably from about 1,000 to 100,000. The number average molecular weight can be measured by gel permeation chromatography (standard material: polystyrene) or the like.

The amount of the adhesive property in the adhesive layer to be added to the resin is preferably in the range of 5% by mass or more and 20% by mass or less based on 100% by mass of the adhesive layer component. When the amount of the tackifying resin to be added is more than 20% by mass, the molecular weight of the adhesive imparting resin is low, and the melt viscosity is extremely lowered. When copretrusion using a T-die or the like is performed, not only It is difficult to laminate the base material layer containing the polypropylene resin as a main component, and the adhesive layer is also viscous, and it is difficult to improve the extraction property of the film from the wound state. On the other hand, if the amount of the adhesive imparting 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 even if it is blended. Therefore, the amount of the tackifying resin to be added is preferably 6% by mass or more and 20% by mass or less. Better at 6 mass% The above range is 15% by mass or less.

In the case where the adhesiveness is imparted to the adhesive layer to reduce the melt viscosity, the base layer and the adhesive layer can be improved by adding a polystyrene resin of about 1% by mass to 15% by mass to the adhesive layer. The difference in melt viscosity between the layers makes the buildup easy. The blending amount of the polystyrene resin is preferably 3% by mass or more and 12% by mass or less, more preferably 5% by mass or more and 10% by mass or less.

Examples of the softening agent include a low molecular weight diene polymer, polyisobutylene, hydrogenated polyisoprene, hydrogenated polybutadiene and derivatives thereof, polybutene, and the like. The molecular weight of the softener is not particularly limited and may be appropriately set. However, if the molecular weight is small, the substance may move from the adhesive layer to the coating or the peeling force may increase. On the other hand, if the molecular weight is increased, There is a tendency to lack the effect of improving the strength. Therefore, the number average molecular weight of the softener is preferably from about 1,000 to 100,000. The number average molecular weight can be measured in the same manner as in the case of the adhesion imparting resin.

Further, the adhesiveness imparting resin and the softener used in the adhesive layer may vary depending on the type of the liquid or the powder, and may also foul the extruder during extrusion. Such a problem can be improved by using a tackifying resin and a softening agent, and a polyethylene resin and a polyolefin resin as a masterbatch. Therefore, the adhesiveness imparting resin and the softener are preferably used as a master batch for the polyethylene resin and the polyolefin resin.

The adhesive force of the adhesive film (adhesive layer) of the present invention is at 23 ° C, and for the acrylic plate system in the range of 200 cN / 25 mm to 1000 cN / 25 mm, It is preferably used for various coverings. If the adhesive force is less than 200 cN/25 mm, it will be rolled up during the protection according to the covering, and it cannot function as a protective film. On the other hand, if the adhesive force is more than 1000 cN/25 mm, there is a fear that the film may not be smoothly peeled off when the film is peeled off from the covering.

In addition, the sheet is in the range of 2cN/25mm to 20cN/25mm at 23 ° C, and is preferably used in consideration of use. If the adhesion is less than 2 cN/25 mm, it will be rolled up during protection and cannot function as a protective film. On the other hand, if the adhesive force is more than 20 cN/25 mm, there is a fear that the film may not be smoothly peeled off when the film is peeled off from the covering. The adhesive force can be appropriately set by changing the resin composition and thickness of the adhesive layer.

In the adhesive layer of the present invention, it is also necessary to contain a known additive. For example, it may contain: a lubricant, an anti-caking agent, a heat stabilizer, an antioxidant, an antistatic agent, a light stabilizer, a flushing improver, and the like. However, these components have a relatively low molecular weight and may bleed out to the surface of the adhesive layer to lower the adhesion of the adhesive layer. Therefore, in the case of using an additive, it is preferred that the low molecular weight mass of the surface of the adhesive layer be 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 order. After washing the surface of the adhesive layer with an organic solvent such as ethanol which does not erode the resin constituting the adhesive layer, the organic solvent is removed from the cleaning liquid by an evaporator or the like, and the value obtained by weighing the residue is divided by washing. The surface area of the surface of the adhesive layer is sought. When the residue is present at 1 mg/m ² or more, it means that impurities are present between the surface of the adhesive layer and the surface of the coated body, and the contact area with the coated body is reduced, which causes a decrease in the vanaural force, and the adhesive force is lowered. In the case of adding an additive, it is necessary to select an additive such as a polymer type, a research addition amount, an addition method, and the like so that the low molecular weight substance (impurity) does not move and is transferred to the adhesive layer.

(release layer)

The adhesive film of the present invention has an adhesive layer on one surface of the substrate layer and a release layer on the opposite side. Thereby, even if the adhesive films are overlapped with each other, adhesion of the adhesive films to each other can be suppressed. By providing the release layer, in particular, the adhesive film is stored in a roll state, and then the film is not easily subjected to partial elongation or deformation when the film is taken out, and it can be used as a film having excellent processing suitability. In order to allow the adhesive films to overlap each other, the adhesive films do not adhere to each other, and surface unevenness is formed in the release layer, and the contact area with the adhesive layer is effective.

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

In order to form the surface unevenness as described above in the release layer, it is effective to mix a non-compatible resin with a polypropylene resin. By doing so, a rough surface layer can be formed in a matte shape. Among them, in the case where a propylene-ethylene block copolymer is used as the polypropylene-based resin, the same effect as that of the resin which does not dissolve in the polypropylene-based resin can be expected. Among them, of course, a resin which is incompatible with the polypropylene resin may be further added to the propylene-ethylene block copolymer.

As the resin which is insoluble in the polypropylene resin, an α-olefin (co)polymer having 4 or more carbon atoms such as a low density polyethylene or a 4-methylpentene-1 (co) polymer can be used. Other examples include linear low-density polyethylene, high-density polyethylene, copolymer of ethylene and a small amount of α-olefin, and ethylene and vinyl acetate. Copolymer, polystyrene, polyester resin, polyamine resin or the like. In particular, in the case of using a 4-methylpentene-1 system (co)polymer, not only the surface of the release layer is matte-like rough, but also the peeling property can be further improved due to a decrease in the surface free energy of the surface of the film.

In view of the resin composition of the adhesive layer of the present invention, the three-dimensional average surface roughness SRa of the surface of the release layer is preferably 0.10 μm or more and 0.50 μm or less. By doing so, the anti-caking property and the protective property of the covering body can be improved. When the surface roughness of the release layer is less than 0.10 μm, the film extractability when the film is in the form of a roll may be deteriorated. When the surface roughness of the release layer is more than 0.50 μm, the surface unevenness of the release layer is transferred to the surface of the adhesive layer, and the adhesion is remarkably lowered. At this time, the surface unevenness of the release layer is more preferably 0.25 μm or more and 0.45 μm or less in terms of the average surface roughness SRa of the surface.

Here, the three-dimensional average surface roughness SRa of the surface of the release layer means an average thickness on the center surface when the sinusoidal curve approximates the surface roughness curve, and can be measured by a surface roughness measuring device or the like.

(self-adhesive surface protection film)

The self-adhesive surface protective film of the present invention comprises a base layer, an adhesive layer, and a release layer containing the above resin component. The thickness of the self-adhesive surface protective film of the present invention is preferably 10 μm or more and 150 μm or less, more preferably 15 μm or more and 120 μm or less, still more preferably 20 μm or more and 100 μm or less. If the total thickness of the film is too thin, the usability is poor, and if it is too thick, the rigidity becomes high and the usability is poor, and the film which is disadvantageous in cost is also formed.

The thickness of the base material layer of the present invention is preferably 5 μm or more and less than 100 μm, more preferably 10 μm or more and 75 μm or less, still more preferably 15 μm or more and 55 μm or less. When the thickness of the base material layer is less than 5 μm, the rigidity is weak, and wrinkles are likely to occur when the protective film is adhered to the covering, and a sufficient adhesive force is not obtained, and if it is 100 μm or more, it becomes a cost surface. Unfavorable film.

The thickness of the adhesive layer of the present invention is preferably 1 μm or more and less than 30 μm. When the thickness of the adhesive layer is less than 1 μm, it is difficult to customize the film by co-extrusion, and if it is 30 μm or more, it becomes a film which is disadvantageous on the cost side. At this time, in the case where the adhesion is increased, the viscosity is preferably considered to increase the thickness of the adhesive layer. By increasing the thickness of the adhesive layer, the contact area and the contact area can be easily increased. The thickness of the adhesive layer is preferably 2 μm or more and 20 μm or less, more preferably 3 μm or more and 15 μm or less, and particularly preferably 4 μm or more and 8 μm or less.

The thickness of the release layer of the present invention is preferably 1 μm or more and 30 μm. When the thickness of the release layer is less than 1 μm, it is difficult to customize the film by co-extrusion, and if it is 30 μm or more, it is a film which is disadvantageous on the cost side. The thickness of the release layer is preferably 2 μm or more and 20 μm or less, and more preferably 3 μm or more and 15 μm or less.

The peeling force of the adhesive film of the present application to the release surface is preferably in the range of 250 cN/40 mm or less at 23 ° C, and is preferable from the viewpoint of film extractability when the adhesive film is in the form of a roll. When the peeling force is more than 250 cN/40 mm, when the adhesive film is in the form of a roll, there is a problem that the film is partially elongated and deformed when the film is taken out. More preferably 200cN/40mm the following. The lower limit of the peeling force of the adhesive surface of the adhesive film with respect to the release surface is about 1 cN/40 mm in actual value, and further about 5 cN/40 mm.

The self-adhesive surface protective film of the present invention is composed of a layer including a base layer, an adhesive layer, and a release layer of the above-mentioned resin component, and constitutes a resin of each layer, for example, by using a uniaxial or twin-screw extruder. It is sent to a T-die of a shunt type or multi-manifold type in a molten state, and is obtained by laminating three layers (base material layer, adhesive layer, release layer) or more. The temperature of the extruder of each layer can be appropriately adjusted in consideration of the molding temperature of the components used in each layer in order to make the layers into a molten state, and can be adjusted, for example, in the range of 200 ° C to 260 ° C. The temperature of the T-die can be the same as the temperature described. The speed from the T-die winding to the casting roll may be any speed as long as the layers are brought to an appropriate thickness, for example, 10 m/min to 200 m/min, preferably 10 m/min to 100 m/min.

The adhesive film of the present invention is suitable for use in a roll form. The width of the film roll and the upper limit of the film roll length are not particularly limited. From the viewpoint of ease of use, the width is generally 1.5 m or less, and the roll length is preferably 40 m or less, preferably 5000 m or less. As the winding core, a plastic core or a metal core such as 3 吋, 6 吋, or 8 通常 can usually be used. Further, from the viewpoint of processing suitability, a film roll wound in a size of 200 m or more and 450 mm or more in width is preferable.

The adhesive film of the present invention is used for protecting members such as ruthenium used for optical applications, synthetic resin sheets (for example, for building materials), stainless steel sheets (for building materials), aluminum sheets, decorative plywood, steel sheets, glass sheets, and home appliances. system Products, precision machinery, and the surface of the car body during manufacture can be used to protect against scratches during stacking, storage, transportation, and manufacturing steps, as well as protection from secondary processing of articles. Scratch in the case of (for example, bending or press working).

The present application claims priority based on Japanese Patent Application No. 2012-89184 filed on Apr. 10, 2012. The entire contents of the specification of Japanese Patent Application No. 2012-89184, filed on Apr.

[Examples]

The following examples are provided to further illustrate the invention. However, the present invention is not limited to the following embodiments as long as it does not deviate from the gist thereof. Among them, the evaluation methods of the physical properties of the following examples and comparative examples are as follows.

(1) Evaluation of adhesion

According to JIS-Z-0237 (2000) tape and adhesive sheet test method, it was measured by the following method.

As a covering, a 50 mm × 150 mm acrylic sheet (made by Mitsubishi Rayon Co., Ltd.: ACRYLITE (registered trademark) 3 mm thick) and a 50 mm × 150 mm cymbal sheet (the lens portion is composed of a triangular prism, and the height of the triangular prism is 25 μm) is prepared. The width of the triangular prism is 50 μm). As a test piece, a test piece having a size of 150 mm in the winding direction when the film was produced and 25 mm in the direction orthogonal thereto was cut out.

Use a rubber roller of 2000g mass (the spring hardness of the roller surface is 80Hs, covered with a rubber layer with a thickness of 6mm, width 45mm, diameter (including rubber) Layer) 95 mm), the cover and the test piece were pressure-bonded one time at a speed of 5 mm/sec. After re-pressurizing and adhering, it was left to stand in an environment of a temperature of 23 ° C and a relative humidity of 65% for 30 minutes, and "Autograph (registered trademark)" (AGS-J) manufactured by Shimadzu Corporation was used at 300 mm/min. The speed is the resistance value at 180 degree peeling, and it becomes the adhesive force [cN/25mm]. The 180 degree peeling means that the peeling angle of the acrylic sheet and the film when the resistance value at the time of peeling is measured is maintained at 180 degrees.

In the measurement, a polyester sheet having a thickness of 190 μm and a size of 25 mm × 170 mm is prepared as a jaw holding portion for measuring a sample, and the end portion of the measurement sample side of the measurement sample obtained by pressure-bonding the test piece and the acrylic sheet is The 15 mm-wide adhesive portion was attached to the polyester sheet with a cellophane tape as a clamp holding portion at the time of measurement. A schematic diagram of the measurement sample is shown in Fig. 1. The measurement was carried out on three samples prepared from the respective films produced in the examples and the comparative examples, and the average value thereof was defined as the adhesion of the sample. The case of the sputum was also measured in the same manner.

(2) Evaluation of peeling force

A double-sided tape (made by Nitto Denko Co., Ltd.) is attached to the entire surface of a 50 mm × 150 mm acrylic sheet (manufactured by Mitsubishi Rayon Co., Ltd.: ACRYLITE (registered trademark) 3 mm thick) to face the adhesive surface of the test piece. In the manner, a test piece of 150 mm (winding direction when the film was produced) × 50 mm (winding direction and orthogonal direction when the film was produced) was attached to the other surface of the double-sided tape.

A test piece having a length of 150 mm in the winding direction when the film was produced and having a length of 40 mm in the direction orthogonal thereto was cut out as a new test piece, and the release sheet of the test piece adhered through the double-sided tape was cut out. After overlapping the adhesive surface and the acrylic plate, a rubber roller of 2000 g mass was used (the spring hardness of the roller surface was 80 Hs, the rubber layer was covered with a thickness of 6 mm, the width was 45 mm, the diameter (including the rubber layer) was 95 mm), and the thickness was 5 mm. The speed of / second will pressurize and stick the release surface and the test piece back and forth once. After pressing the adhesive, the winding direction is 100mm, in a direction orthogonal to the total area of 40mm to 4000mm ² of 60Kg load is applied, and at a temperature of 40 ℃, after 24 hours of 65% relative humidity environment, cooled to At 23 °C, the resistance value at 180 degree peeling at a speed of 300 mm/min was used as the peeling force [cN/40 mm] using "Autograph (registered trademark)" (AGS-J) manufactured by Shimadzu Corporation.

At the time of measurement, a polyester sheet having a thickness of 190 μm and a size of 40 mm × 170 mm was prepared as a clamp portion for measuring the sample, and a cellophane tape was attached to the end portion of the test piece of 150 mm × 40 mm at a thickness of 15 mm. Clamp grip. The measurement system was performed three times on one sample, and the average value thereof was used as the peeling force of the sample.

(3) Extraction from the film roll

After winding a long strip to obtain a wound body of 550 mm width and 500 m length, it was stored in a roll state for 7 days under a light-shielding environment of a temperature of 23 ° C and a humidity of 75%. After the stored film was wound up to another plastic core (diameter 9 cm) for 300 m, the end of the film was stretched with a handle and pulled back 3 m. When rewinding, it was visually confirmed whether the film was locally elongated or deformed. Those without local elongation or deformation were rated as ○ (good), and those with local elongation or deformation were rated as × (bad).

(4) MFR measurement of resin

The measurement was carried out in accordance with JIS-K7210.

(5) Determination of bending modulus of resin

The measurement was carried out in accordance with ASTM D747-70.

(6) Determination of ethylene component in styrene elastomer

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

[Example 1] (Production of substrate layer)

100% by mass of the homopolypropylene resin (manufactured by Sumitomo Chemical Co., Ltd.: FLX80E4, 230 ° C MFR: 7.5 g/10 min) was melt-extruded into a substrate layer at 240 ° C using a 90 mm φ uniaxial extruder.

(production of adhesive layer)

40% by mass of a styrene-based elastomer (a hydride of a block copolymer of styrene and butadiene, manufactured by ASAHI KASEI CHEMICALS: Tuftec (registered trademark) H1221, a styrene component ratio of 12% by mass, and an ethylene component ratio of 18 Mass%, 230 ° C MFR: 4.5 g/10 min), 50% by mass of ethylene-α-olefin copolymer (manufactured by Sumitomo Chemical Co., Ltd.: CX3007, 190 ° C MFR: 3.7 g/10 min, modulus of elasticity: 26 MPa) and 10% by mass A petroleum resin (manufactured by Arakawa Chemical Co., Ltd.: ARKON (registered trademark) P125) was melt-extruded into an adhesive layer at 210 ° C using a 45 mm φ single-axis extruder.

(production of release layer)

90% by mass of a propylene-ethylene block copolymer (made of Japanese polypropylene: BC3HF) and 10% by mass of a low-density polyethylene resin (manufactured by Ube Industries: R300) It was melt extruded into a release layer at 230 ° C using a 65 mm φ single-axis extruder.

(production of film)

The base material layer, the pressure-sensitive adhesive layer, and the release layer were laminated and extruded in a three-layer T-die (flow divider type, lip width: 850 mm, lip gap: 1 mm) at 245 ° C in a molten state by respective extruders. The extruded film was taken up at a speed of 20 m/min to a casting roll at a temperature of 30 ° C, and solidified by cooling to obtain a substrate layer thickness of 28 μm, an adhesive layer thickness of 6 μm, a release layer thickness of 6 μm, and a film width of 600 mm. Three 3-layer unstretched films having a film length of 1100 m. Then, the film was subjected to a take-up tension of 40 N, and a strip of 50 N was applied to the film width direction while the rubber roll was used to cut the strip at a speed of 50 m/min to obtain an unstretched film having a film width of 550 mm and a film length of 500 m. film.

[Embodiment 2]

In the same manner as in Example 1, the base layer and the release layer were changed to the following contents, and three types of three-layer unstretched films were obtained in the same manner as in Example 1.

(production of adhesive layer)

60% by mass of a styrene-based elastomer (manufactured by ASAHI KASEI CHEMICALS: Tuftec (registered trademark) H1221, styrene component ratio: 12% by mass, ethylene component ratio: 18% by mass, 230°C MFR: 4.5 g/10 min) and 40 mass The % ethylene-α-olefin copolymer (manufactured by Sumitomo Chemical Co., Ltd.: CX3007, 190 ° C MFR: 3.7 g/10 min, elastic modulus: 26 MPa) was melt-extruded into an adhesive layer at 210 ° C using a 45 mm φ single-axis extruder.

[Example 3]

In the same manner as in Example 1, the base layer and the release layer were changed to the following contents, and three types of three-layer unstretched films were obtained in the same manner as in Example 1.

(production of adhesive layer)

40% by mass of a styrene-based elastomer (a hydride of a block copolymer of styrene and butadiene, manufactured by ASAHI KASEI CHEMICALS: Tuftec (registered trademark) H1221, a styrene component ratio of 12% by mass, and an ethylene component ratio of 18 Mass%, 230 ° C MFR: 4.5 g/10 min), 50% by mass of ethylene-α-olefin copolymer (manufactured by Sumitomo Chemical Co., Ltd.: VL100, 190 ° C MFR: 0.8 g/10 min, elastic modulus: 64 MPa) and 10% by mass The petroleum resin (manufactured by Arakawa Chemical Co., Ltd.: ARKON (registered trademark) P125) was melt-extruded into an adhesive layer at 210 ° C using a 40 mm φ single-axis extruder.

[Example 4]

In the same manner as in Example 1, the base layer and the release layer were changed to the following contents, and three types of three-layer unstretched films were obtained in the same manner as in Example 1.

(production of adhesive layer)

85% by mass of a styrene-based elastomer (manufactured by ASAHI KASEI CHEMICALS: Tuftec (registered trademark) H1041, styrene component ratio: 30% by mass, ethylene component ratio: 49% by mass, 230°C MFR: 5.0 g/10 min), and 5 masses % ethylene-α-olefin copolymer (manufactured by Sumitomo Chemical Co., Ltd.: CX3007, 190 ° C MFR: 0.8 g/10 min, elastic modulus: 26 MPa) and 10% by mass of stone An oleoresin (manufactured by Arakawa Chemical Co., Ltd.: ARKON (registered trademark) P125) was melt-extruded into an adhesive layer at 210 ° C using a 40 mm φ single-axis extruder.

[Example 5]

The base material layer and the release layer were the same as in Example 1, except that the adhesive layer was changed to the following, and the thickness of the base material layer was 26 μm, the thickness of the adhesive layer was 8 μm, and the thickness of the release layer was 6 μm. Three kinds of three-layer unstretched films were obtained in the same manner as in Example 1.

(production of adhesive layer)

60% by mass of a styrene-based elastomer (manufactured by ASAHI KASEI CHEMICALS: Tuftec (registered trademark) H1221, styrene component ratio: 12% by mass, ethylene component ratio: 18% by mass, 230°C MFR: 4.5 g/10 min) and 40 mass The % ethylene-α-olefin copolymer (manufactured by Sumitomo Chemical Co., Ltd.: CX3007, 190 ° C MFR: 3.7 g/10 min, elastic modulus: 26 MPa) was melt-extruded into an adhesive layer at 210 ° C using a 45 mm φ single-axis extruder.

[Embodiment 6]

The base material layer and the release layer were the same as in Example 1, except that the adhesive layer was changed to the following, and the thickness of the base material layer was 30 μm, the thickness of the adhesive layer was 4 μm, and the thickness of the release layer was 6 μm. Three kinds of three-layer unstretched films were obtained in the same manner as in Example 1.

(production of adhesive layer)

40% by mass of a styrene-based elastomer (manufactured by ASAHI KASEI CHEMICALS: Tuftec (registered trademark) H1221, styrene component ratio: 12% by mass, ethylene component ratio: 18% by mass, 230°C MFR: 4.5 g/10 min), 55 mass% of ethylene-α-olefin copolymer (manufactured by Sumitomo Chemical Co., Ltd.: CX3007, 190°C MFR: 3.7 g/10 min, elastic modulus: 26 MPa) and 5% by mass of petroleum resin (AKBON (registered trademark) P125) was melt extruded into an adhesive layer at 210 ° C using a 45 mm φ single-axis extruder.

[Comparative Example 1]

In the same manner as in Example 1, the base layer and the release layer were changed to the following contents, and three types of three-layer unstretched films were obtained in the same manner as in Example 1.

(production of adhesive layer)

70% by mass of a styrene-based elastomer (manufactured by ASAHI KASEI CHEMICALS: Tuftec (registered trademark) H1221, styrene component ratio: 12% by mass, ethylene component ratio: 18% by mass, 230°C MFR: 4.5 g/10 min), 20 mass % of ethylene-α-olefin copolymer (manufactured by Sumitomo Chemical Co., Ltd.: CX3007, 190 ° C MFR: 3.7 g/10 min, elastic modulus: 26 MPa) and 10% by mass of petroleum resin (ARKON (registered trademark) P125) It was melt extruded into an adhesive layer at 210 ° C using a 40 mm φ single-axis extruder.

[Comparative Example 2]

In the same manner as in Example 1, the base layer and the release layer were changed to the following contents, and three types of three-layer unstretched films were obtained in the same manner as in Example 1.

(production of adhesive layer)

70% by mass of a styrene-based elastomer (manufactured by ASAHI KASEI CHEMICALS: Tuftec (registered trademark) H1221, styrene composition ratio 12% by mass, ethylene component ratio: 18% by mass, 230 ° C MFR: 4.5 g/10 min), 20% by mass of ethylene-α-olefin copolymer (manufactured by Sumitomo Chemical Co., Ltd.: VL100, 190 ° C MFR: 0.8 g/10 min, elastic mold) The number: 64 MPa) and 10 mass% of petroleum resin (ARKON (registered trademark) P125 manufactured by Arakawa Chemical Co., Ltd.) were melt-extruded into an adhesive layer at 210 ° C using a 40 mm φ single-axis extruder.

[Comparative Example 3]

20% by mass of styrene-based elastomer (manufactured by ASAHI KASEI CHEMICALS: Tuftec (registered trademark) H1221, styrene component ratio: 12% by mass, ethylene component ratio: 18% by mass, 230°C MFR: 4.5 g/10 min), 70 mass % of ethylene-α-olefin copolymer (manufactured by Sumitomo Chemical Co., Ltd.: CX3007, 190 ° C MFR: 3.7 g/10 min, elastic modulus: 26 MPa) and 10% by mass of petroleum resin (ARKON (registered trademark) P125) It was melt extruded into an adhesive layer at 210 ° C using a 40 mm φ single-axis extruder.

[Comparative Example 4]

In the same manner as in Example 1, the base layer and the release layer were changed to the following contents, and three types of three-layer unstretched films were obtained in the same manner as in Example 1.

(production of adhesive layer)

40% by mass of styrene-based elastomer (manufactured by ASAHI KASEI CHEMICALS: Tuftec (registered trademark) H1221, styrene component ratio: 12% by mass, ethylene component ratio: 18% by mass, 230°C MFR: 4.5 g/10 min), 50 mass % of homopolypropylene (manufactured by Sumitomo Chemical Co., Ltd.: FLX80E4, 190 ° C MFR: 7.5 g/10 min) and 10% by mass of petroleum resin (Arakawa Chemical Co., Ltd.: ARKON (registered trademark) P125) was melt extruded into an adhesive layer at 210 ° C using a 40 mm φ single-axis extruder.

The above results are shown in Tables 1 and 2.

As is clear from Table 2, the films obtained in Examples 1 to 6 had practically sufficient adhesion when used as a protective film, and the peeling property when the film was taken out from the film roll was also good.

On the other hand, in the films obtained in Comparative Examples 1 and 2, the peeling property at the time of extracting the film from the film roll was not good. The adhesion of the film obtained in Comparative Examples 3 and 4 to the covering body was not sufficient. Thus, the films obtained in the comparative examples were all of poor quality and low in practicality.

Claims (5)

A self-adhesive surface protective film characterized in that: by coextruding an adhesive layer on one side of a substrate layer composed of a polypropylene resin, and coextruding a layer of a release layer on the opposite side; The resin constituting the adhesive layer contains at least a styrene-based elastomer and a polyethylene-based resin, and the styrene-based elastic system has a block of a styrene-based polymer block and a butadiene-based polymer block. a hydride of a copolymer, or a hydride of a block copolymer having a styrene polymer block and a random copolymer block of styrene and butadiene, the polyethylene resin-based ethylene homopolymer and Or the ethylene-α-olefin copolymer, and the content of the styrene-based elastomer in the adhesive layer is 35 mass% or more and 99 mass% or less, and the content of the polyethylene resin is 1 mass% or more and 65 mass% or less. Further, the ethylene component in the styrene-based elastomer and the polyethylene-based resin are contained in an amount of 35 mass% or more and less than 70 mass%. The self-adhesive polypropylene film according to claim 1, wherein the polyethylene resin used in the adhesive layer has a bending modulus of 10 MPa or more and less than 90 MPa. The self-adhesive polypropylene film according to claim 1 or 2, wherein the MFR (190 ° C, 2.16 kgf) of the polyethylene resin in the adhesive layer is 0.5 to 8 g/10 min. The self-adhesive polypropylene film according to any one of claims 1 to 3, wherein the MFR (230 ° C, 2.16 kgf) of the styrene elastomer in the adhesive layer is 0.5 to 8 g/10 min. The self-adhesive polypropylene film according to any one of claims 1 to 4, wherein the polypropylene resin in the base material layer has an MFR (230 ° C, 2.16 kgf) of 1.0 to 15 g/10 min.