TWI600739B - Self-adhesive surface protection film - Google Patents

Description

Self-adhesive surface protection film

The present invention relates to a self-adhesive surface protective film (adhesive film). The adhesive film of the present invention can be applied to members such as ruthenium sheets used for protecting 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 automobile bodies at the time of manufacture; to protect articles from damage during transport during stacking, storage, transport, or manufacturing; and to protect articles from secondary processing (such as bending or pressurization) The situation of injury.

In the past, the adhesive film for the surface protection of the covering has been used for processing, storage, and transportation of building materials, electrical, electronic products, automobiles, etc., and such an adhesive film has good adhesion and must be After use, the surfaces are not contaminated by the adhesive and can be easily peeled off.

In recent years, the above-mentioned coating system has been diversified, and not only the coating surface is smooth, but also many surface irregularities are seen. Examples of the covering having the surface unevenness include a 透镜-type lens portion for a cymbal of an optical member. In the case of a coated body having a surface unevenness such as a ruthenium, in order to exhibit sufficient adhesion in use, it is considered to improve the adhesion of the adhesive layer, so that an adhesive force can be obtained even if the contact area is small.

In order to improve the adhesion of the adhesive layer, it is possible to use a styrene-based elastomer exhibiting high adhesion as a main component of the resin. However, if the adhesive force of the adhesive layer is increased, the film is stored in a roll state. When the film is rolled out, adhesion occurs, and problems such as partial elongation or deformation of the film occur.

Conventionally, by applying an adhesive layer and a release layer to a base film, an adhesive film having excellent adhesion and film-out property from a film in a roll state is obtained. However, these films are responsible for the problem of using a solvent having an environmental load and a complicated production process, and in recent years, an adhesive film produced by melt-extruding a full layer of a film has been actively developed.

When the adhesive film is produced by melt-extruding the entire film, it is possible to add a fluorine-based resin or a polyfluorene-based resin to the base material layer (see, for example, Patent Documents 1, 2, etc.) or a saturated fatty acid. In the case of reviewing the diterpene amine (for example, refer to Patent Document 3, etc.), when the resin is stored in a roll state, the resin may be transferred to the adhesive layer, and the adhesion may be reduced or the coating may be contaminated. .

In addition, it is also considered to add a polyethylene-based resin to the adhesive layer (for example, refer to Patent Documents 4 and 5), but it is not possible to simultaneously satisfy the adhesion to the crucible, and to store the film in a roll state and then roll out the film. The above question.

Prior technical literature Patent literature

Patent Document 1 JP-A-2008-81589

Patent Document 2, JP-A-2008-308559

Patent Document 3, Patent No. 4565058

Patent Document 4 Japanese Patent Publication No. 08-73822

Patent Document 5, JP-A-2007-161882

The problem to be solved by the present invention is to provide a self-adhesive surface protective film which, on the one hand, exhibits strong adhesion to a covering body, and can be used for a wide variety of coverings, even in a reel state. When the adhesive film is stored and the film is unwound, problems such as partial elongation or deformation of the film are less likely to occur, and the film has excellent processing suitability.

The present inventors focused on the review and found that the above problems can be solved, and the present invention has been achieved.

That is, the present invention relates to a self-adhesive surface protective film characterized in that an adhesive layer is laminated on one surface of a base material layer composed of a polypropylene-based resin by co-extrusion, and a release layer is laminated on the opposite surface. Layered, the maximum adhesion to the acrylic sheet is 800cN/25mm or more, the maximum adhesion to the acrylic sheet is taken as the denominator, and the ratio of the release force of the release layer to the adhesive layer is taken as the molecular ratio. 0.003 to 0.18.

According to the present invention, it is possible to obtain a self-adhesive surface protective film which, on the one hand, exhibits a strong adhesive force to a covering body, and can be used for a wide variety of covering bodies, and even if the adhesive film is stored in a roll state, When the film is rolled out, problems such as partial elongation or deformation of the film are less likely to occur, and the film has excellent processing suitability.

In this case, the resin constituting the adhesive layer contains at least a styrene-based elastomer and a polyethylene-based resin, and 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 resin is preferably 1% by mass or more and 65% by mass or less, and the sum of the ethylene component and the polyethylene resin in the styrene-based elastomer is preferably 35 mass% or more and less than 70 mass% in the adhesive layer component.

Moreover, in this case, the MFR (melt flow rate) (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.

Further, in this case, the resin used for the release layer is preferably a non-polyoxyl resin.

The adhesive film according to the present invention has the following advantages: on the one hand, it exhibits a strong adhesive force to the covering body, and can be used for a wide variety of covering bodies, and the adhesive film is stored even in a roll state, and then rolled. When the film is formed, problems such as partial elongation or deformation of the film are less likely to occur, and the film has excellent processing suitability.

Fig. 1 is a model diagram of a sample for measuring adhesion.

[Formation of the Invention]

The present invention is a self-adhesive surface protective film (adhesive film) characterized in that an adhesive layer is laminated on one surface of a substrate layer composed of a polypropylene resin by co-extrusion, and a release layer is laminated on the opposite surface. Layered, the maximum adhesion to the acrylic sheet is 800cN/25mm or more, the maximum adhesion to the acrylic sheet is taken as the denominator, and the ratio of the release force of the release layer to the adhesive layer is taken as the molecular ratio. 0.003 to 0.18.

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

The adhesion of the adhesive film of the present invention is preferably at 23 ° C, and is in the range of 800 to 1200 cN / 25 mm for the acrylic sheet, if it is considered to be used for a wide variety of coatings. The acryl plate used for this evaluation used 88% by mass or more of a methacrylic resin. When the adhesive force is less than 800 cN/25 mm, depending on the covering, curling or the like may occur during protection, and the function as a protective film may not be carried. On the other hand, when the adhesive force exceeds 1200 cN/25 mm, the film may not be smoothly peeled off when the film is peeled off from the covering.

Further, in consideration of use, the adhesion to the enamel sheet at 23 ° C is preferably in the range of 2 to 20 cN / 25 mm. If the adhesion is less than 2 cN/25 mm, curling or the like occurs during protection, and the function as a protective film cannot be carried. On the other hand, if the adhesive force exceeds 20 cN/25 mm, there is a possibility that the film cannot be peeled off smoothly when the film is peeled off. The adhesive force can appropriately set the adhesive force by changing the resin composition or thickness of the adhesive layer.

The adhesive film of the present invention is pressed against the viewpoint of the adhesion of the film and the roll-out property of the film when it is in the form of a roll. The maximum adhesion of the force plate is taken as the denominator, and the ratio of the release force of the release layer to the adhesive layer as a molecule is preferably in the range of 0.003 to 0.18. If the ratio is more than 0.18, the adhesion force of the film to the acrylic sheet and the peeling force of the release layer and the adhesive layer become approximate values, and the adhesive force may be insufficient, and the adhesive body may not exhibit adhesive force or peel off. When the force is high, when the film is in the form of a roll, the roll-out property of the film is deteriorated. The lower limit of the ratio is about 0.003 in actual value. Further, in the examples described later, the adhesive force was measured by a width of 25 mm, and the peeling force was measured by a width of 40 mm. Therefore, the above ratio was taken as a denominator with a value of 1.6 times (40 ÷ 25). And calculate the value.

(base material layer)

The adhesive film of the present invention requires a base material layer containing a polypropylene resin as a main component, and examples of the polypropylene resin used herein include crystalline polypropylene, a random copolymer of propylene and a small amount of α-olefin, or In particular, as the crystalline polypropylene resin, a n-heptane-insoluble homopolymer propylene homopolymer or propylene containing 60% by weight or more, which is used for ordinary extrusion molding, etc., may be mentioned. The copolymer of propylene and other α-olefins may be used singly or as a mixture of propylene homopolymer or propylene and other α-olefins.

The base material layer preferably contains 60% by mass or more of propylene units, more preferably 70% by mass or more of propylene units. When the propylene unit is less than 60% by mass, the film does not have a feeling of stiffness, and handling becomes difficult. In addition, when a polyethylene resin is used in a unit amount of propylene of less than 60% by mass, the film becomes soft and easily stretched, and when the film is wound up, problems such as partial elongation or deformation of the film are likely to occur.

In this case, the intrinsic n-heptane insolubleness is a safety in which the crystallinity of the polypropylene is used as an index. In the present invention, it is used in accordance with the No. 20 of the Ministry of Health and Welfare of the Republic of Japan in February, 57, in accordance with the The alkane insoluble property (the elution at 25 ° C for 60 minutes is 150 ppm or less (the use temperature is more than 100 ° C is 30 ppm or less) is preferred.

Examples of the α-olefin copolymerization component of the copolymer of propylene and another α-olefin include an α-olefin having 2 to 8 carbon atoms, such as ethylene or 1-butene, 1-pentene, and 1-hexene. And an α-olefin of C4 or higher such as 4-methyl-1-pentene. The copolymer to be used herein is preferably a random or block copolymer obtained by polymerizing one or two or more kinds of propylene and the above-exemplified α-olefin. 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, two or more kinds of copolymers of propylene and another α-olefin may be used in combination.

Further, when the film obtained in the present invention is subjected to product processing, the resulting waste film may be regranulated as a raw material for recovery and added to the substrate layer. Production costs can be suppressed by using recycled raw materials.

(adhesive layer)

As the resin constituting the adhesive layer of the present invention, in order to exhibit high adhesion, a styrene-based elastomer is preferably used. Moreover, in order to exhibit the adhesive force and the roll-out property of the film from the roll state, it is preferable to add a polyethylene resin. Further, by adding a polyethylene-based resin, the peeling force against the release surface from the adhesive surface side can be reduced. Further, in order to control the adhesion, a polyolefin resin other than a polyethylene resin, a tackifier resin, a softener, polystyrene, or the like may be mixed as needed.

Examples of the styrene-based elastomer system include an ABA type block polymer such as styrene-butadiene-styrene, an AB type block polymer such as a styrene-butadiene copolymer, and a styrene polymer block. A hydrogenated product such as a block copolymer of a random copolymer block of styrene and butadiene, or a hydride of a styrene-based random copolymer such as styrene-butadiene rubber.

Examples of the polyethylene resin include low density polyethylene, a copolymer of ethylene and an α-olefin, and the like. Among these, while maintaining the adhesive force while reducing the peeling force of the film from the roll state and improving the roll-out property of the film, low-density polyethylene, in particular, a linear low called LLDPE is used. Density polyethylene or ultra low density polyethylene called VLDPE is preferred. These are short-chain branches introduced into the ethylene chain by copolymerization of an α-olefin, and flexibility can be imparted to the polyethylene-based resin depending on the type or copolymerization amount of the α-olefin. The α-olefin is not particularly limited, and examples thereof include 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, and 1-octene.

The amount of the styrene-based elastomer in the adhesive layer is preferably from 35% by mass to 99% by mass in order to exhibit high adhesion and exhibiting the roll-out property of the film from the roll state. If it is less than 35% by mass, the adhesive force is lowered, and it is difficult to obtain the necessary adhesive force. The amount of the styrene-based elastomer in the adhesive layer is preferably in the range of 40% by mass or more and 90% by mass or less.

In order to exhibit high adhesion and reduce the peeling force of the film from the roll state, the roll-out property is exhibited, and the amount of the polyethylene-based resin in the adhesive layer is preferably 1% by mass or more and 65% by mass or less. When the amount of the polyethylene-based resin in the adhesive layer exceeds 65% by mass, the adhesive force is lowered, and it is 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 to 60% by mass.

The sum of the ethylene component and the polyethylene 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 polyethylene resin is 70% by mass or more of the adhesive layer component, the adhesive strength is lowered, and sufficient adhesive force cannot be obtained. When the sum of the ethylene component and the polyethylene resin is less than 35% by mass in the adhesive layer component, the peeling force of the film adhesive layer with respect to the release layer becomes high. The sum of the ethylene component and the polyethylene resin is preferably 40% by mass or more and 65% by mass or less in the adhesive layer component. More preferably, the sum of the ethylene component and the polyethylene resin is 45 mass% or more and 63 mass% or less in the adhesive layer component.

In terms of film formability, 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/10 min. The scope.

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 to 8 g/10 min, more preferably in the range of 0.8 to 7.0 g/10 min. By setting it as the above range, film formation in which the thickness of each layer is uniform becomes easy.

The styrene component in the styrene-based elastomer is preferably 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 (particles) becomes difficult, and if it exceeds 40% by mass, the adhesive force is lowered, and it is difficult to obtain the necessary adhesive force. The styrene component in the styrene-based elastomer is more preferably in the range of 10% by mass to 30% by mass. On the other hand, the ethylene component in the styrene-based elastomer is easily mixed with the polyethylene-based resin when the polyethylene-based resin is added, and it is considered that if the content in the styrene-based elastomer is large, the reel is obtained from the reel. State film The effect of improving the roll-out property tends to become large. Therefore, the ethylene component in the styrene elastomer is preferably 15% by mass or more and 70% by mass or less. In addition, it is considered that the ethylene component in the styrene-based elastomer greatly contributes to the adhesion. When the amount is more than 70% by mass, when the polyethylene-based resin is added under the following conditions, the adhesive strength tends to be lowered.

Further, 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, and particularly preferably 80% by mass or more. Further, the ethylene component of the polyethylene resin is preferably 98% by mass or less, more preferably 96% by mass or less, and still more preferably 95% by mass or less. When the ethylene component in the polyethylene resin is less than 70% by mass, the effect of improving the roll-out property of the film from the roll state tends to be small. The resin which is 70% by mass or more of the ethylene component in the polyethylene resin is CX3007 or VL100 manufactured by Sumitomo Chemical Co., Ltd., and the like.

Incidentally, the component other than the ethylene component in the polyethylene resin is preferably less than 30% by mass, and more preferably 25% by mass or less.

The density of the polyethylene resin is preferably 850 to 920 kg/m ³ , more preferably 860 to 910 kg/m ³ , most preferably 880 to 906 kg/m ³ . By being in the above range, it is easy to achieve both good adhesion and roll-out properties.

The flexural modulus of the polyethylene resin is preferably 10 MPa or more and less than 90 MPa. When it is 10 MPa or more, the roll-out property of the film from the roll state is further increased, and if it is less than 90 MPa, the adhesive force is further increased. The flexural modulus of the polyethylene resin is more preferably in the range of 15 to 80 MPa, and particularly preferably in the range of 20 to 70 MPa.

The polyolefin resin other than the polyethylene resin 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 low adhesive strength when they are blended in a small amount, and are preferably blended at a ratio of 1% by mass to 20% by mass.

Examples of the tackifier resin include petroleum resins, aliphatic hydrocarbon resins, alicyclic hydrocarbon resins, aromatic hydrocarbon resins, terpene resins, coumarone-indene resins, styrene resins, and rosin resins. The molecular weight of the tackifier resin is not particularly limited, and may be appropriately set. However, if the molecular weight is small, there is a possibility that the material from the adhesive layer is transferred to the covering or re-peeled, and the like. When the molecular weight is increased, the adhesion improving effect tends to be poor, so the number average molecular weight of the tackifying resin is preferably about 1,000 to 100,000. The number average molecular system can be determined by gel permeation chromatography or the like.

The blending amount of the tackifier resin in the adhesive layer is preferably in the range of 3% by mass to 20% by mass based on 100% by mass of the adhesive layer component. When the blending amount of the tackifying resin exceeds 20% by mass, since the tackifying resin has a low molecular weight and the melt viscosity is extremely low, when performing co-extrusion film formation using a T die or the like, not only polypropylene is used. It is difficult to laminate the base material layer containing the resin as a main component, and the adhesive layer becomes sticky, and it is difficult to improve the roll-out property of the film from the roll state. Further, if the blending amount of the tackifying resin in the adhesive layer is less than 3% by mass, the adhesion of the adhesive layer does not change even if blended. The blending amount of the tackifier resin is preferably 5% by mass or more and 15% by mass or less.

When the melt viscosity is lowered due to the addition of the tackifying resin in the adhesive layer, the polystyrene resin of about 1% by mass to 15% by mass may be added to improve the relationship between the substrate layer and the adhesive layer. The melt viscosity is poor, making it easy to laminate. 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 or 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 small, there is a cause of transfer or re-peeling of the material from the adhesive layer to the covering, and if the molecular weight is changed, Large, there is a tendency to improve the adhesion effect, so the number average molecular weight of the softener is preferably about 1000 to 100,000. The number average molecular weight can be measured by the same method as in the case of the tackifying resin.

Further, the tackifying resin or softener used in the adhesive layer is a liquid or a powder depending on the type, and may also contaminate the extruder during extrusion. Since such a problem can be improved by using a tackifying resin or a softening agent in combination with a polyethylene resin or a polyolefin resin, it is preferred to use a tackifying resin or a softening agent and a polyethylene resin. Or the polyolefin resin is used as a master batch.

The adhesive film of the present invention may contain a known additive as needed. For example, it may contain a slip agent, an anti-blocking agent, a heat stabilizer, an antioxidant, an antistatic agent, a light stabilizer, an impact modifier, and the like. However, these components have a relatively low molecular weight and may bleed out the surface of the adhesive layer and reduce the adhesion of the adhesive layer. Therefore, when an additive is used, it is preferred that the low molecular weight substance on the surface of the adhesive layer is less than 1 mg/m ² .

Here, the measurement of the low molecular weight substance on the surface of the adhesive layer was carried out by the following procedure. The surface of the adhesive layer is washed with an organic solvent such as ethanol which does not attack the resin constituting the adhesive layer, and the organic solvent is removed from the washing liquid by an evaporator or the like, and the value obtained by weighing the residue is divided by the washed amount. The surface area of the surface of the adhesive layer is obtained. When the residue is present at 1 mg/m ² or more, foreign matter is present between the surface of the adhesive layer and the surface of the coated body, and the contact area is reduced, and the vanaural force is lowered. Therefore, the adhesive strength is not preferable. When adding an additive, it is necessary to select an additive such as a polymer type, or to review the amount of addition, the method of addition, and the like so as not to transfer or transfer the adhesive layer.

(release layer)

The adhesive film of the present invention is formed on the opposite side of the adhesive layer laminated on one surface of the base material layer, and forms a release layer composed of a polypropylene resin which is not a polyoxymethylene resin, and thus even The adhesive films are overlapped with each other, and the adhesion of the adhesive films to each other is also reduced. In particular, even when the adhesive film is stored in a roll state and then the film is wound up, problems such as partial elongation or deformation of the film are less likely to occur, and the film has excellent processing suitability. Further, the adhesive films are not adhered to each other even if they are overlapped with each other, and it is effective to form surface irregularities on the release layer and to reduce the contact area with the adhesive layer.

It is effective to form a non-coherent resin in a polypropylene-based resin in order to form the surface unevenness as described above. By doing so, a matte surface can be formed as a rough layer. Furthermore, by using a propylene-ethylene block As a polypropylene resin, the polymer can be expected to have the same effect without using an incompatible resin. Further, it is of course also possible to add an incompatible resin to the propylene-ethylene block copolymer.

As the resin which is incompatible with the polypropylene resin, an α-olefin (co)polymer having a carbon number of 4 or more, such as a low-density polyethylene or a 4-methylpentene-1 (co)polymer, is preferably used. Further, a linear low-density polyethylene, a high-density polyethylene, a copolymer of ethylene and a small amount of an α-olefin, a copolymer of ethylene and vinyl acetate, a polystyrene, a polyester resin, and a polyfluorene may be mentioned. An amine resin or the like. In particular, the 4-methylpentene-1 (co)polymer not only roughens the surface to a felt shape, but also improves the peeling property because the surface free energy of the surface of the film is lowered.

The peeling force of the adhesive surface of the adhesive film of the present invention on the release surface is preferably in the range of 250 cN/40 mm or less at 23 ° C from the viewpoint of the film unwinding property when the adhesive film is in the form of a roll. When the peeling force exceeds 250 cN/40 mm, when the film is wound up in the form of a roll, the film may be partially elongated or deformed. Further, as an actual value, the lower limit of the peeling force of the adhesive surface of the adhesive film to the release surface is about 1 cN/40 mm, and further about 5 cN/40 mm.

The maximum adhesion of the adhesive film of the present invention to the acrylic sheet is taken as the denominator, the release layer and the adhesive layer, from the point of the adhesion of the film and the roll-out property of the film in the form of a roll. The ratio of the peeling force to the molecule is preferably in the range of 0.003 to 0.18. If the ratio is greater than 0.18, the adhesion of the film to the acrylic sheet is similar to the peeling force of the release layer and the adhesive layer, and the adhesive force may not be charged. In the case of the coating, the adhesion is not exhibited, or the peeling force is high, and when the roll form is formed, the problem that the film is unwound is deteriorated. As the actual value, the lower limit of the ratio is about 0.003. Further, as described above, the above ratio is calculated in consideration of the width of the sample at the time of measurement, and is preferably in the range of 0.01 to 0.18, more preferably in the range of 0.05 to 0.15.

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-blocking 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 unwinding property may be deteriorated when the film is formed into a roll form. When the surface roughness of the release layer is higher 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. In this case, it is more preferable that the surface unevenness of the release layer is such that the average surface roughness SRa of the surface is 0.25 μm or more and 0.45 μm or less.

In addition, the ternary mean surface roughness SRa of the surface of the mold release layer means the average roughness of the center surface when the surface roughness curve is approximated by a sinusoid, and can be measured by a surface roughness measuring apparatus or the like.

(adhesive film)

The thickness of the adhesive layer of the adhesive film 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 is a film which is disadvantageous in terms of cost.

At this time, when the adhesion is to be increased, it is preferable to increase the thickness in consideration of the viscosity. By increasing the thickness of the adhesive layer, the contact area with the covering It is easy to get bigger. 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 10 μm or less.

The thickness of the base material layer of the adhesive film 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, and 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 feeling of stiffness is weak, and when it is attached to the covering as a protective film, wrinkles are likely to occur, and the problem of insufficient adhesion is not obtained, and if it is 100 μm or more, it becomes a problem. A film that is unfavorable in terms of cost.

The thickness of the release layer of the adhesive film of the present invention is preferably 1 μm or more and less than 30 μm. When the thickness of the adhesive film 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 in terms of cost. The thickness of the release layer is more preferably 2 μm or more and 20 μm or less, and particularly preferably 3 μm or more and 15 μm or less. Further, 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, and still more preferably 20 μm or more and 100 μm or less. When the total thickness of the film is too thin, it may be difficult to handle, and if it is too thick, the rigidity becomes high and the workability is poor, and at the same time, it is a case of a film which is disadvantageous in terms of cost.

The self-adhesive surface protective film of the present invention is composed of a substrate layer containing the above resin component, an adhesive layer, and a release layer, and the resin constituting each layer is made of, for example, a uniaxial or biaxial extruder. The feed head type or multi-manifold type T die is directly sent out in a molten state, and is obtained by extrusion of three or more layers. In order to make the layers melt In the state, the temperature of the extruder of each layer can be appropriately adjusted in consideration of the forming temperature of the components used in each layer, and can be adjusted, for example, in the range of 200 ° C to 260 ° C. The temperature of the T die can also be the same as the above temperature.

The adhesive film of the present invention is preferably handled in the form of a roll. The width of the film roll and the upper limit of the winding length are not particularly limited, but generally, the width is preferably 1600 mm or less from the viewpoint of ease of handling, and the winding length is 5000 m or less when the film thickness is 40 μm. Further, as the winding core, a plastic core or a metal core of 3 吋, 6 吋, or 8 通常 can be usually used.

Further, from the viewpoint of processing suitability, a film roll wound up to a size of 100 m or more and a width of 450 mm or more is preferable.

The adhesive film of the present invention can be used for members such as ruthenium sheets used for protecting optical applications, synthetic resin sheets (for example, for building materials), stainless steel sheets (for building materials), aluminum sheets, decorative plywood, steel sheets, glass sheets, home electric appliances. , precision machinery and the surface of the car body during manufacturing; to protect the article from damage during transport during stacking, storage, transport or process; and to protect the article from damage during secondary processing such as bending or pressurization The situation.

[Examples]

Next, the present invention will be further described by way of examples. However, the present invention is not limited by the following examples as long as it does not deviate from the gist of the invention. In addition, the evaluation methods of the physical properties in the following examples and comparative examples are as follows.

(1) Evaluation of adhesion

It was measured in accordance with JIS-Z-0237 (2000) Adhesive tape ‧ Adhesive test method by the following method.

As a covering, a 50 mm × 150 mm acrylic sheet (made by Mitsubishi Ray: 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) Width 50 μm), as a test piece, a test piece having a winding direction of 150 mm at the time of film production and a direction of 25 mm orthogonal thereto was used, and a rubber roller having a mass of 2000 g was used (spring hardness of the roller surface was 80 Hs to thickness) A 6 mm rubber layer was coated with a width of 45 mm and a diameter (including a rubber layer of 95 mm), and the test piece was pressed back to the covering body at a speed of 5 mm/sec. After the pressure-bonding, using Autograph (registered trademark) (AGS-J) manufactured by Shimadzu Corporation, the product was allowed to stand at a temperature of 23 ° C and a relative humidity of 65% for 30 minutes, and was peeled at 180 degrees at a speed of 300 mm/min. The maximum resistance is taken as the adhesion [cN/25mm]. The 180-degree peeling means that the peeling angle of the acrylic sheet and the film is maintained at 180 degrees when the resistance value at the time of peeling is measured.

At the time of measurement, a polyester sheet having a thickness of 190 μm and a size of 25 mm×170 mm was prepared as a nip portion for measuring the sample, and the edge of the adhesive film side of the measurement sample to which the adhesive film and the acrylic sheet were pressure-bonded was adhered to a portion of 15 mm. The width is attached using a cellophane tape as a grip portion at the time of measurement. A model diagram of the measurement sample is shown in Fig. 1. The measurement system was performed three times on one sample, and the average value was used as the adhesion of the sample.

(2) MFR measurement of resin

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

(3) Determination of flexural modulus of resin

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

(4) Determination of ethylene component in styrene elastomer

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

(5) Evaluation of peeling force

Double-sided tape (made by Nitto Denko) on the acrylic sheet (Mitsubishi Twist: Acrylite (registered trademark) 3mm thick) 50mm × 150mm, on the other side of the double-sided tape, with the adhesive side of the test piece In the manner in which it was produced, a test piece of 150 mm (winding direction at the time of film production) × 50 mm (direction orthogonal to the winding direction at the time of film production) was attached.

As a new test piece, it was cut into 150 mm in the winding direction of the film, and a test piece of 40 mm in the direction orthogonal thereto was attached to the acrylic sheet with the adhesive surface and the double-sided tape interposed therebetween. After the release surface of the upper test piece was superposed, a rubber roller having a mass of 2000 g (the spring hardness of the surface of the reel was 80 Hs, the width of the rubber layer covered with a thickness of 6 mm was 45 mm, and the diameter (including the rubber layer) was 95 mm) was used. Back and forth at a speed of 5 mm / sec, pressure-bonded release surface and test piece. After pressure sticky, ² a load of 60kg for the take-up direction and 100mm in the direction perpendicular thereto in the total area of 40mm 4000mm, at a temperature of 40 ℃, stand for 24 hours at a relative humidity of 65% of the environment by cooling to 23 ℃ The peeling force was evaluated by using "Autograph (registered trademark)" (AGS-J) manufactured by Shimadzu Corporation and peeling at 180 degrees at a speed of 300 mm/min.

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 holding portion of the measurement sample, and was attached to the edge of a test piece of 150 mm × 40 mm by using a cellophane tape at a width of 15 mm of the adhesive portion. The clamping part. In the measurement, the average value of the resistance values at the time of peeling from 40 mm to 60 mm among the pressure-sensitive adhesive portions of the test piece was taken as the peeling force [cN/40 mm] of the test piece. The measurement system was carried out 3 times, and the average value was taken as the final peeling force.

(6) Taking the maximum adhesion force of the acrylic sheet as the denominator, the ratio of the peeling force of the release layer and the adhesive layer to the molecular ratio

The width of the sample at the time of measurement is taken into consideration. Specifically, the value of the peeling force of the above (5) is 25/40 times as a value.

(7) Rolling out from the reel

A film wound body having a width of 550 mm and a diameter of 500 m was obtained by cutting, and then stored in a roll state for 7 days in a light-shielding environment having a temperature of 23 ° C and a humidity of 75%. Regarding this storage reel, immediately after rewinding 300 m on another plastic core (diameter 9 cm), the end of the film was grasped by hand and stretched, and unrolled by 3 m. When unwinding, visually confirm whether there is a partial elongation or deformation of the film. A part of the elongation or deformation is regarded as ○ (good), and a part of the elongation or deformation is regarded as × (bad).

[Example 1] (Production of substrate layer)

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

(production of adhesive layer)

40% by mass of a styrene-based elastomer (manufactured by Asahi Kasei Chemical Co., Ltd.: 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% by mass Ethylene ‧ α-olefin copolymer (manufactured by Sumitomo Chemical Co., Ltd.: CX3007, 190 ° C MFR: 3.7 g/10 min, flexural modulus: 26 MPa) and 10% by mass of petroleum resin (Arakawa Chemical Co., Ltd.: Arkon (registered trademark) P125 It was melt extruded at 210 ° C as an adhesive layer using a 40 mm Φ single-axis extruder.

(production of release layer)

90% by mass of a propylene-ethylene block copolymer (made of Japanese propylene: BC3HF) and 10% by mass of a low-density polyethylene resin (manufactured by Ube Industries: R300) were melted at 230 ° C using a 65 mm Φ single-axis extruder. Extrusion was carried out as a release layer.

(production of film)

The base material layer, the adhesive layer, and the release layer were each laminated in a molten state at each of 245 ° C using a three-layer T die (feed head type, lip width 850 mm, lip gap 1 mm). The extruded film was drawn 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, a film width of 600 mm, and a film. Three 3-layer unstretched films of 1100 m in length. Further, this film was cut at a tensile force of 40 N by a rubber roller to a film width of 50 N 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.

[Embodiment 2]

The base material layer and the release layer were maintained as in Example 1, and the adhesive layer was changed to the following. 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 Chemical Co., Ltd.: 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% by mass The ethylene ‧ α-olefin copolymer (manufactured by Sumitomo Chemical Co., Ltd.: CX3007, 190 ° C MFR: 3.7 g/10 min, flexural modulus: 26 MPa) was melt extruded at 210 ° C as an adhesive layer using a 40 mm Φ single-axis extruder.

[Example 3]

The base material layer and the release layer were maintained as in Example 1, and the adhesive layer was changed to the following. 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 Chemical Co., Ltd.: 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% by mass Ethylene ‧ α-olefin copolymer (manufactured by Sumitomo Chemical Co., Ltd.: VL100, 190 ° C MFR: 0.8 g/10 min, flexural modulus: 64 MPa) and 10% by mass of petroleum resin (Arakawa Chemical Co., Ltd.: Arkon (registered trademark) P125 It was melt extruded at 210 ° C as an adhesive layer using a 40 mm Φ single-axis extruder.

[Example 4]

The base material layer and the release layer were maintained as in Example 1, and the adhesive layer was changed to the following. Three kinds 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 Chemical Co., Ltd.: Tuftec (registered trademark) H1041, styrene component ratio: 30% by mass, ethylene component ratio: 49% by mass, 230 ° C MFR: 5.0 g/10 min), 5% by mass Ethylene. Α-olefin copolymer (manufactured by Sumitomo Chemical Co., Ltd.: CX3007, 190° C. MFR: 0.8 g/10 min, flexural modulus: 26 MPa) and 10% by mass of petroleum resin (manufactured by Arakawa Chemical Industry Co., Ltd.: Arkon (registered trademark) P125) with 40 mm Φ A single-axis extruder was melt extruded at 210 ° C as an adhesive layer.

[Example 5]

First, this is a reference example. The base material layer and the release layer were maintained as in Example 1, and the adhesive layer was changed to the following except that the thickness of the base material layer was 24 μm, the thickness of the adhesive layer was 10 μm, and the thickness of the release layer was 6 μm. In the same manner as in Example 1, three kinds of three-layer unstretched films were obtained.

(production of adhesive layer)

50% by mass of styrene-based elastomer (manufactured by Asahi Kasei Chemical Co., Ltd.: Tuftec (registered trademark) H1221, styrene component ratio: 12% by mass, ethylene component ratio: 18% by mass, 230 ° C MFR: 4.5 g/10 min), 37% by mass Ethylene. Α-olefin copolymer (manufactured by Sumitomo Chemical Co., Ltd.: CX3007, 190° C. MFR: 3.7 g/10 min, flexural modulus: 26 MPa) and 13% by mass of petroleum resin (manufactured by Arakawa Chemical Industry Co., Ltd.: Arkon (registered trademark) P125) at 40 mm Φ A single-axis extruder was melt extruded at 210 ° C as an adhesive layer.

[Embodiment 6]

The base material layer and the release layer were maintained as in Example 1, and the adhesive layer was changed to the following except that 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. In the same manner as in Example 1, three kinds of three-layer unstretched films were obtained.

(production of adhesive layer)

40% by mass of a styrene-based elastomer (manufactured by Asahi Kasei Chemical Co., Ltd.: 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 55 mass% Ethylene ‧ α-olefin copolymer (manufactured by Sumitomo Chemical Co., Ltd.: CX3007, 190 ° C MFR: 3.7 g/10 min, flexural modulus: 26 MPa) and 5% by mass of petroleum resin (manufactured by Arakawa Chemical Industry Co., Ltd.: Arkon (registered trademark) P125 It was melt extruded at 210 ° C as an adhesive layer by a 40 mm Φ single-axis extruder.

[Comparative Example 1]

The base material layer and the release layer were maintained as in Example 1, and the adhesive layer was changed to the following. Three kinds 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 Chemical Co., Ltd.: 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% by mass Ethylene ‧ α-olefin copolymer (manufactured by Sumitomo Chemical Co., Ltd.: CX3007, 190 ° C MFR: 3.7 g/10 min, flexural modulus: 26 MPa) and 10% by mass of petroleum resin (Arakawa Chemical Co., Ltd.: Arkon (registered trademark) P125 It was melt extruded at 210 ° C as an adhesive layer by a 40 mm Φ single-axis extruder.

[Comparative Example 2]

The base material layer and the release layer were maintained as in Example 1, and the adhesive layer was changed to the following. Three kinds 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 Chemical Co., Ltd.: 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% by mass Ethylene ‧ α-olefin copolymer (manufactured by Sumitomo Chemical Co., Ltd.: VL100, 190 ° C MFR: 0.8 g/10 min, flexural modulus: 64 MPa) and 10% by mass of petroleum resin (Arakawa Chemical Co., Ltd.: Arkon (registered trademark) P125 It was melt extruded at 210 ° C as an adhesive layer by a 40 mm Φ single-axis extruder.

[Comparative Example 3]

20% by mass of a styrene-based elastomer (manufactured by Asahi Kasei Chemical Co., Ltd.: 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% by mass Ethylene ‧ α-olefin copolymer (manufactured by Sumitomo Chemical Co., Ltd.: CX3007, 190 ° C MFR: 3.7 g/10 min, flexural modulus: 26 MPa) and 10% by mass of petroleum resin (Arakawa Chemical Co., Ltd.: Arkon (registered trademark) P125 It was melt extruded at 210 ° C as an adhesive layer by a 40 mm Φ single-axis extruder.

[Comparative Example 4]

The base material layer and the release layer were maintained as in Example 1, and the adhesive layer was changed to the following. 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 Chemical Co., Ltd.: 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% by mass Uniform polypropylene (manufactured by Sumitomo Chemical Co., Ltd.: FLX80E4, 190 ° C MFR: 7.5 g/10 min) and 10% by mass of petroleum resin (manufactured by Arakawa Chemical Industry Co., Ltd.: Arkon (registered trademark) P125) with a 40 mm Φ single-axis extruder at 210 °C melt extrusion as an adhesive layer.

[Comparative Example 5]

The base material layer and the release layer were maintained as in Example 1, and the adhesive layer was changed to the following. Three kinds of three-layer unstretched films were obtained in the same manner as in Example 1.

(production of adhesive layer)

a hydrogenated body of a random copolymer of 80% by mass of styrene and butadiene (manufactured by JSR: Dynaron (registered trademark) 1320P, a styrene component ratio of 10% by mass, an ethylene component ratio of 22% by mass, 230 ° C MFR: 3.5 g/10min), 10% by mass of petroleum resin (Arkon (registered trademark) P125 manufactured by Arakawa Chemical Industry Co., Ltd.) and 10% by mass of ethylene ‧α-olefin copolymer (manufactured by Sumitomo Chemical Co., Ltd.: CX3007, 190°C MFR: 3.7g/ 10 min, bending elastic modulus: 26 MPa) was melt extruded at 210 ° C as an adhesive layer in a 40 mm Φ single-axis extruder.

The above results are shown in Tables 1 and 2.

As is clear from Table 1, the films obtained in Examples 1 to 6 have a practically sufficient adhesive force when used as a protective film, and the roll-out property when the film is wound up as a roll is also good.

On the other hand, in the films obtained in Comparative Examples 1, 2, and 5, the unwinding property when the film was taken up as a roll could not be said to be good. The films obtained in Comparative Examples 3 and 4 were not sufficient for the adhesion of the covering. As described above, the film systems obtained in the comparative examples were all of poor quality and low practicality.

Claims (6)

A self-adhesive surface protective film characterized in that an adhesive layer having a thickness of 1 μm or more and 10 μm or less is laminated on one surface of a base material layer made of a polypropylene-based resin by co-extrusion, and a layer is deposited on the opposite side. The mold layer is formed, wherein the adhesive layer contains 3% by mass or more and 10% by mass or less of the tackifying resin with respect to 100% by mass of the adhesive layer component; and the maximum adhesive force for the acrylic sheet is 800 cN/25 mm or more, which is for pressure The maximum adhesion of the kelly plate is taken as the denominator, and the ratio of the peeling force of the release layer to the adhesive layer is taken as a molecule of 0.003 to 0.14. The self-adhesive surface protection film according to claim 1, wherein the resin constituting the adhesive layer contains at least a styrene-based elastomer and a polyethylene-based resin, and the content of the styrene-based elastomer in the adhesive layer is 35 mass% or more and 99 mass%. In the following, the content of the polyethylene resin is 1% by mass or more and 65% by mass or less, and the sum of the ethylene component and the polyethylene resin in the styrene elastomer is 35 mass% or more and less than 70 mass% in the adhesive layer component. The self-adhesive surface protective film of claim 2, wherein the polyethylene resin in the adhesive layer has a MFR (melt flow rate) (190 ° C, 2.16 kgf) of 0.5 to 8 g/10 min. The self-adhesive surface protective film of claim 2, wherein the styrene-based elastomer in the adhesive layer has an MFR (230 ° C, 2.16 kgf) of 0.5 to 8 g/10 min. The self-adhesive surface protection 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. The self-adhesive surface protective film according to any one of claims 1 to 4, wherein the resin-based non-polyoxyphthalic resin used for the release layer.