JP6506556B2 - Self-adhesive surface protection film - Google Patents

Description

  The present invention relates to a self-adhesive surface protective film (adhesive film). The adhesive film of the present invention is a member such as a prism sheet used for optical applications, a synthetic resin plate (for example, for building materials), a stainless steel plate (for example, for building materials), aluminum plate, decorative plywood, steel plate, glass plate To protect the surface of home electric appliances, precision machinery, and automobile bodies at the time of manufacture, to protect them from being damaged when stacked, stored, transported, or transported in the manufacturing process, as well as It can be suitably used when protecting from being scratched during secondary processing (e.g., bending or pressing).

  Heretofore, adhesive films intended for surface protection of coverings have been used during processing, storage and transportation of construction materials, electricity, electronic products, automobiles, etc. Such adhesive films have good adhesiveness. As well as having them, after use, they should be able to be easily peeled off without contaminating each surface with an adhesive.

  In recent years, the coating described above has been diversified, and not only a coating having a smooth surface but also a coating having a surface asperity may be seen in large numbers. As a covering which has surface asperity, a prism type lens part of a prism sheet used for an optical member, etc. are mentioned, for example. In order to develop sufficient adhesion for use with a cover having a surface asperity such as a prism sheet, the adhesion of the adhesion layer is increased so that adhesion can be obtained even if the contact area is small, etc. Is considered.

  In order to increase the adhesive strength of the adhesive layer, it is possible to use a styrenic elastomer or the like exhibiting high adhesive strength as a resin as a main component, but when the adhesive strength of the adhesive layer is increased, the film is stored in a roll Then, when the film is subsequently fed out, blocking occurs and problems such as partial stretching and deformation of the film occur.

  Heretofore, a pressure-sensitive adhesive film excellent in adhesion and delivery properties of a film from a roll state has been obtained by applying a pressure-sensitive adhesive layer and a release layer on a substrate film. However, these films have the problem that the use of solvents and their production processes, which may cause environmental impact, become complicated, and adhesive films produced by melt-extruding all the films are actively developed in recent years. It became so.

  When producing a pressure-sensitive adhesive film by melt-extruding all layers of the film, as a countermeasure for the above, a fluorine-based resin, a silicone-based resin (for example, see Patent Documents 1 and 2) or a saturated fatty acid bisamide is used as a substrate layer. (For example, refer to Patent Document 3 and the like.) Studies have been made to add it, etc. However, there is a possibility that these resins may transfer to the adhesive layer when storing them in roll state, which lowers the adhesive force. Or contaminating the coating, etc. can not be wiped out.

  Moreover, addition of a polyethylene-based resin to the adhesive layer has also been studied (see, for example, Patent Documents 4 and 5), but the adhesive strength to the prism and the film are stored in a roll state, and then the film It is not something that satisfies the above-mentioned problems when feeding out.

JP 2008-81589 A JP 2008-308559 A Patent No. 4565058 gazette Japanese Patent Application Publication No. 08-73822 JP 2007-161882 A

  The problem to be solved by the present invention is that even when the adhesive film is stored in a roll state and then the film is fed out, while showing strong adhesive force to the coating and being usable for various coatings, It is an object of the present invention to provide a self-adhesive surface protective film which is less likely to cause problems such as the film being partially stretched or deformed, and which is excellent in processability of the film.

As a result of intensive studies, the present inventors have found that the above-mentioned problems can be solved, and reach the present invention.
That is, according to the present invention, an adhesive layer is laminated on one side of a base material layer made of polypropylene resin and a release layer is laminated on the other side by coextrusion, and the maximum adhesive strength to an acrylic plate is 800 cN / 25 mm or more. According to the self-adhesive surface protective film characterized in that a ratio of 0.003 to 0.18 when the peeling force between the releasing layer and the adhesive layer is taken as a numerator and the maximum adhesive force to the plate is taken as a denominator. It is a thing.

  According to the present invention, the adhesive film is stored in a roll state while showing a strong adhesive force to the coating and being usable for various coatings, and the film is partially obtained also when the film is subsequently fed out. It is difficult to cause problems such as elongation and deformation, and a self-adhesive surface protective film excellent in processability of the film can be obtained.

  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% by mass to 99% by mass, the content of the polyethylene-based resin Is preferably 1% by mass or more and 65% by mass or less, and the sum of the ethylene component in the styrene elastomer and the polyethylene resin is preferably 35% by mass or more and less than 70% by mass in the adhesive layer component.

  Moreover, in this case, it is preferable that MFR (190 degreeC, 2.16 kgf) of the polyethylene-type resin in the said adhesion layer is 0.5-8 g / 10min.

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

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

  Furthermore, in this case, it is preferable that the resin used for the release layer is a non-silicone resin.

  The pressure-sensitive adhesive film according to the present invention exhibits strong adhesion to a covering, and while being usable for various coverings, the pressure-sensitive adhesive film is stored in a roll state, and the film is a part It is difficult to cause problems such as elongation and deformation, and has an advantage of being excellent in processability of the film.

It is a schematic diagram of the measurement sample of adhesive force.

In the present invention, an adhesive layer is laminated on one side of a base material layer made of a polypropylene resin by coextrusion on the other side, and an acrylic resin is used while having a maximum adhesive strength of 800 cN / 25 mm or more. Self-adhesive surface protection film (adhesion (adhesion) characterized by the ratio of 0.003 to 0.18 when the peeling force between the release layer and the adhesive layer is taken as the numerator and the maximum adhesive force to the plate as the denominator Film).
Hereinafter, the embodiment of the adhesive film of the present invention will be described.

The adhesive strength of the pressure-sensitive adhesive film of the present invention is preferably in the range of 800 to 1200 cN / 25 mm with respect to an acrylic plate at 23 ° C. in consideration of use for various coatings. The acrylic board used for this evaluation uses what contains 88 mass% or more of methacrylic resin. When the adhesive strength is less than 800 cN / 25 mm, depending on the cover, curling may occur when protecting, and the function as a protective film may not be carried out. On the other hand, when the adhesive strength exceeds 1200 cN / 25 mm, there is a possibility that the film can not be peeled off smoothly when the film is peeled off from the coated body.
Moreover, it is preferable in consideration of use that the adhesive force to a prism sheet is in the range of 2 to 20 cN / 25 mm at 23 ° C. If the adhesive strength is less than 2 cN / 25 mm, then curling or the like occurs when protecting, and it can not bear the function as a protective film. On the other hand, when the adhesive strength exceeds 20 cN / 25 mm, there is a possibility that the film can not be peeled off smoothly. The adhesive force can be appropriately set by changing the resin composition, thickness and the like of the adhesive layer.

  The film has a ratio of 0.003 to 0.18 when taking the maximum adhesion of the pressure-sensitive adhesive film of the present invention to the acrylic plate as the denominator and taking the peeling force between the release layer and the pressure-sensitive adhesive layer as the molecule. It is preferable from the point which makes compatible the delivery property of the film at the time of setting it as the roll form, and the adhesive force of this. When this ratio is larger than 0.18, the adhesion of the film to the acrylic plate and the peel strength between the release layer and the adhesion layer become close values, and the adhesion is insufficient and does not exhibit adhesion depending on the cover. Or, the peeling force is high, which causes problems such as deterioration of the delivery property of the film in the roll form. The lower limit of this ratio is about 0.003 as a realistic value. In the examples described later, since the adhesive force is measured at 25 mm width and the peel force at 40 mm width, the above ratio is calculated by using a value obtained by multiplying the adhesive force by 1.6 times (40/25) as the denominator It will be a value.

(Base material layer)
The pressure-sensitive adhesive film of the present invention requires a base layer mainly composed of a polypropylene-based resin, and as the polypropylene-based resin used here, crystalline polypropylene, random copolymer or block of propylene and a small amount of α-olefin Copolymers and the like can be mentioned, and more specifically, as a crystalline polypropylene resin, n-heptane-insoluble isotactic propylene homopolymer used in ordinary extrusion molding or the like, or propylene containing 60% by mass or more Copolymers of propylene and other α-olefins may be mentioned, and the propylene homopolymers or copolymers of propylene and other α-olefins may be used alone or in combination.
The base material layer preferably contains 60% by mass or more of propylene units, and more preferably 70% by mass or more. If the propylene unit content is less than 60% by mass, the film may lose its feel and handling may become difficult. In addition, when the propylene unit amount is less than 60% by mass or a polyethylene resin is used, the film becomes flexible and easily stretches, and even when the film is fed out, the film partially stretches or deforms, etc. Is more likely to occur.
Here, n-heptane insolubility refers to the crystallinity of polypropylene and simultaneously indicates safety, and in the present invention, n-heptane insolubility according to Ministry of Health and Welfare notification No. 20, February 1982 (25 ° C., 60 ° C.) It is a preferred embodiment to use one which is compatible with an elution fraction of 150 ppm or less (a temperature exceeding 100 ° C. is 30 ppm or less) at the time of partial extraction.

As an α-olefin copolymer component of a copolymer of propylene and another α-olefin, α-olefins having 2 to 8 carbon atoms, such as ethylene or 1-butene, 1-pentene, 1-hexene, 4 -C4 or more alpha olefins, such as-methyl 1-pentene, are mentioned. Here, the copolymer is preferably a random or block copolymer obtained by polymerizing propylene with one or more α-olefins exemplified above. The range of 1.0-15 g / 10 minutes is preferable, and the range of 2.0-10.0 g / 10 minutes of the melt flow rate (MFR: 230 degreeC, 2.16 kgf) of the polypropylene resin to be used is more preferable. Moreover, the copolymer of propylene and another alpha-olefin can also be used in mixture of 2 or more types.
Furthermore, it is also possible to re-granulate the scrap film that has come out during product processing of the film obtained in the present invention as a recovered raw material and add it to the base material layer. By using the recovered raw material, it is possible to reduce the production cost.

(Adhesive layer)
As resin which comprises the adhesion layer of this invention, in order to express high adhesive force, it is suitable to use a styrene-type elastomer. Moreover, it is preferable to add a polyethylene-based resin in order to express the adhesive strength and the delivery property of the film from the roll state. Furthermore, the peeling force with respect to a mold release surface can be made low from the adhesive surface side by adding a polyethylene-type resin. Moreover, in order to control adhesive force, polyolefin resin other than polyethylene-type resin, tackifying resin, a softener, a polystyrene, etc. can also be mixed as needed.

  Styrene-based elastomers include an A-B-A type block polymer such as styrene-butadiene-styrene, an A-B-type block polymer such as styrene-butadiene copolymer, and a random copolymer of styrene-based polymer block and styrene and butadiene. A hydrogenated substance such as a block copolymer with a united block, and a hydrogenated substance of a styrene random copolymer such as a styrene-butadiene rubber can be mentioned.

  Examples of the polyethylene-based resin include low density polyethylene and copolymers of ethylene and α-olefin. Among these, low density polyethylene, in particular linear low density polyethylene called LLDPE, and ultra low density polyethylene called VLDPE reduce the peeling force of the film from the roll state while maintaining the adhesive strength, and the film It is further preferable to improve the delivery property of These are obtained by introducing short-chain branching into an ethylene chain by copolymerizing an α-olefin, and it is possible to impart flexibility to a polyethylene-based resin depending on the type and the amount of the α-olefin. Although it does not specifically limit as an alpha-olefin, 1-butene, 1-pentene, 1-hexene, 4-methyl- 1-pentene, 1-octene etc. are mentioned.

  The amount of the styrene-based elastomer in the adhesive layer is preferably 35% by mass or more and 99% by mass or less in order to develop high adhesion and expression of the film from the roll state. If it is less than 35% by mass, the adhesive strength is reduced, and it becomes difficult to obtain the required adhesive strength. The amount of the styrene-based elastomer in the adhesive layer is preferably in the range of 40% by mass to 90% by mass.

  The amount of the polyethylene-based resin in the adhesive layer is preferably 1% by mass or more and 65% by mass or less in order to develop high adhesion and lower the peel strength of the film from the roll state, and to develop delivery properties. . When the amount of the polyethylene-based resin in the adhesive layer exceeds 65% by mass, the adhesive strength is reduced, and it becomes difficult to obtain the required adhesive strength. The amount of the polyethylene resin in the adhesive layer is preferably in the range of 3% by mass to 60% by mass.

  The sum of the ethylene component in the styrene elastomer and the polyethylene resin is in the range of 35% by mass or more and less than 70% by mass in the adhesive layer component. When the sum of the ethylene component and the polyethylene resin is 70% by mass or more in the adhesive layer component, the adhesive strength is lowered, and a sufficient adhesive strength can not be obtained. When the sum of the ethylene component and the polyethylene-based resin is less than 35% by mass in the adhesive layer component, the peeling force of the film adhesive layer to the release layer becomes high. Preferably, the sum of the ethylene component and the polyethylene resin is 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 preferably 45% by mass or more and 63% by mass or less in the adhesive layer component.

The melt flow rate (MFR: 230 ° C., 2.16 kgf) of the styrenic elastomer used is preferably in the range of 0.5 to 8 g / 10 min in terms of film forming property, and 2.0 to 7.0 g / 10 min Is more preferable.
The range of 0.5-8 g / 10 minutes is preferable, and the range of 0.8-7.0 g / 10 minutes of the melt flow rate (MFR: 190 degreeC, 2.16 kgf) of the polyethylene-type resin to be used is more preferable. By setting it as the said range, film forming which made thickness of each layer uniform becomes easy to perform.

  The styrene component in the styrene-based elastomer is desirably 5% by mass or more and 40% by mass or less. If it is less than 5% by mass, granulation at the time of preparation of the resin (pellet) becomes difficult, and if it exceeds 40% by mass, the adhesive strength is lowered, and it becomes difficult to obtain the required adhesive strength. The styrene component in the styrene-based elastomer is 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 easily mixed with the polyethylene-based resin when the polyethylene-based resin is added, and therefore, when the content in the styrene-based elastomer is large, the delivery improvement effect of the film from the roll state is It is thought that it is easy to become large. Therefore, it is desirable that the ethylene component in the styrenic elastomer is 15% by mass or more and 70% by mass or less. Further, the ethylene component in the styrenic elastomer is considered to greatly contribute to the development of adhesive strength, so when it exceeds 70% by mass, the adhesive strength is less likely to be reduced when a polyethylene-based resin is added under the following conditions There is a tendency.

Moreover, it is preferable that the ethylene component in polyethylene-type resin is 70 mass% or more. The ethylene component of the polyethylene-based resin is more preferably 75% by mass or more, still more preferably 80% by mass or more. Moreover, 98 mass% or less is preferable, as for the ethylene component of polyethylene-type resin, More preferably, it is 96 mass% or less, More preferably, it is 95 mass% or less. If the ethylene component in the polyethylene-based resin is less than 70% by mass, the effect of improving the delivery property of the film from the roll state tends to be small. Examples of resins having an ethylene content of 70% by mass or more in polyethylene resins include CX3007 and VL100 manufactured by Sumitomo Chemical Co., Ltd.
Incidentally, it is preferable that components other than the ethylene component in a polyethylene-type resin are less than 30 mass%, More preferably, it is 25 mass% or less.

Preferably the density of the polyethylene resin is 850~920kg / m ^3, more preferably a 860~910kg / m ^3, most preferably 880~906kg / m ^3. By setting it as the said range, it becomes easy to be able to make favorable adhesiveness and delivery property make compatible.

  The flexural modulus of the polyethylene resin is preferably 10 MPa or more and less than 90 MPa. The delivery property of the film from a roll state is further improved as it is 10 MPa or more, and adhesive force is further improved as it is less than 90 MPa. The flexural modulus of the polyethylene resin is more preferably in the range of 15 to 80 MPa, and still more preferably in the range of 20 to 70 MPa.

  The polyolefin-based resin other than the polyethylene-based resin is not particularly limited, and examples thereof include crystalline polypropylene, a copolymer of propylene and a small amount of α-olefin, and the like. In general, these resins tend to decrease in adhesion only by blending in a small amount, and therefore, it is preferable to blend them in a proportion of 1% by mass or more and 20% by mass or less.

  Examples of the tackifier resin include petroleum resin, aliphatic hydrocarbon resin, alicyclic hydrocarbon resin, aromatic hydrocarbon resin, terpene resin, coumarone / indene resin, styrene resin, rosin resin and the like. The molecular weight of the tackifying resin is not particularly limited and can be set appropriately. However, if the molecular weight is small, there is a possibility that it may cause transfer of substance from the adhesive layer to the cover or heavy peeling, and when the molecular weight is large The number average molecular weight of the tackifier resin is preferably about 1000 to 100,000, because the adhesive improvement effect tends to be poor. The number average molecular weight can be measured by gel permeation chromatography or the like.

  The compounding amount of the tackifier resin in the adhesive layer is preferably in the range of 3% by mass to 20% by mass with respect to 100% by mass of the adhesive layer component. When the content of the tackifying resin exceeds 20% by mass, the viscosity of the tackifying resin is extremely low because the molecular weight of the tackifying resin is low, and the polypropylene resin is mainly used when performing coextrusion film formation using a T die or the like. Not only the lamination with the base material layer becomes difficult, but also the adhesive layer becomes sticky, and it tends to be difficult to improve the delivery property of the film from the roll state. Moreover, even if it mix | blends that the compounding quantity of tackifying resin in the adhesion layer is less than 3 mass%, it does not contribute to the adhesive force change of the adhesion layer. The blending amount of the tackifier resin is preferably 5% by mass or more and 15% by mass or less.

  When the melt viscosity tends to decrease due to the addition of the tackifying resin in the adhesive layer, the melt viscosity difference between the base material layer and the adhesive layer can be obtained by adding about 1% by mass to 15% by mass of the polystyrene resin. Can improve and make 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 softener include low molecular weight diene polymers, polyisobutylene, hydrogenated polyisoprene, hydrogenated polybutadiene and derivatives thereof, and polybutene. The molecular weight of the softener is not particularly limited and can be set appropriately. However, if the molecular weight is small, there is a possibility that substance transfer or heavy exfoliation from the adhesive layer to the cover may be caused. The softening agent preferably has a number average molecular weight of about 1,000 to 100,000 because the effect of improving the strength tends to be poor. The number average molecular weight can be measured by the same method as in the case of the tackifier resin.

  Moreover, the tackifying resin and the softener used in the adhesive layer are, depending on the type, a liquid or a powder, and some substances may contaminate the extruder at the time of extrusion. Such problems can be ameliorated by using a tackifier resin or a softener as a masterbatch with a polyethylene resin or a polyolefin resin, so that the tackifier resin or a softener can be used as a master resin with a polyethylene resin or a polyolefin resin. It is preferable to use it in

The pressure-sensitive adhesive film of the present invention can contain known additives as required. For example, a lubricant, an antiblocking agent, a heat stabilizer, an antioxidant, an antistatic agent, a light resistance agent, an impact modifier, etc. may be contained. However, these components have a relatively low molecular weight and may bleed out on the surface of the adhesive layer to reduce the adhesive strength of the adhesive layer. Therefore, when using an additive, it is preferable to make the low molecular weight substance on the adhesive layer surface less than 1 mg / m ² .
Here, the measurement of the low molecular weight substance on the surface of the adhesive layer was performed in the following procedure. The adhesion layer surface is washed using an organic solvent that does not erode the resin that constitutes the adhesion layer, such as ethanol, and the organic solvent is removed from the washing solution by an evaporator or the like, and the residue is weighed to determine the adhesion value It was divided by the surface area of the layer surface to obtain. Here, when the residue is 1 mg / m ² or more, foreign matter is present between the surface of the adhesive layer and the surface of the cover, which reduces the contact area and reduces the van der Waals force. Unfavorably reduced. In the case of adding an additive, it is necessary to prevent the transfer and transfer to the adhesive layer by selecting an additive such as a polymer type or examining the amount and method of addition.

(Release layer)
In the pressure-sensitive adhesive film of the present invention, a release layer made of a polypropylene resin which is a non-silicone resin is formed on the side opposite to the pressure-sensitive adhesive layer laminated on one side of the base material layer. Even if it stacks, blocking of adhesive films decreases. In particular, even when the adhesive film is stored in a roll state and thereafter the film is fed out, problems such as partial elongation or deformation of the film do not easily occur, and the film is excellent in processability. In order to prevent blocking of the pressure-sensitive adhesive films even when the pressure-sensitive adhesive films are stacked, it is effective to form surface irregularities on the release layer to reduce the contact area with the pressure-sensitive adhesive layer.

  In order to form the surface as described above, it is effective to mix a non-compatible resin with a polypropylene resin. By doing so, a layer having a rough surface can be formed in a mat-like manner. By using a propylene-ethylene block copolymer as the polypropylene resin, the same effect can be expected without using an incompatible resin. Of course, it is also possible to add a further incompatible resin to the propylene-ethylene block copolymer.

  As resin incompatible with polypropylene resin, C4 or more alpha-olefin (co) polymers, such as low density polyethylene and 4-methyl pentene 1 type (co) polymer, are used suitably. Besides, linear low density polyethylene, high density polyethylene, copolymer of ethylene and a small amount of α-olefin, copolymer of ethylene and vinyl acetate, polystyrene, polyester resin, polyamide resin and the like are mentioned. Be In particular, the 4-methylpentene-1 (co) polymer not only roughens the surface in a mat-like manner, but also the improvement of releasability can be expected by lowering the surface free energy of the film surface.

  It is preferable that the peeling force with respect to the mold release surface of the adhesive surface of the adhesive film of this invention is 250 cN / 40 mm or less in 23 degreeC from the point of the delivery property of the film at the time of making an adhesive film into a roll form. When the peeling force exceeds 250 cN / 40 mm, problems occur such as the film partially elongates or deforms when the pressure-sensitive adhesive film is in roll form. The lower limit of the peeling force of the pressure-sensitive adhesive surface of the pressure-sensitive adhesive film to the release surface is about 1 cN / 40 mm as a practical value, and further about 5 cN / 40 mm.

  The ratio of the adhesive force of the adhesive film of the present invention to the acrylic plate as the denominator and the peel force between the release layer and the adhesive layer as the molecule is in the range of 0.003 to 0.18. It is preferable from the point which makes compatible the delivery property of the film at the time of setting it as the roll form, and the adhesive force of this. When this ratio is larger than 0.18, the adhesion of the film to the acrylic plate and the peel strength between the release layer and the adhesion layer become close values, and the adhesion is insufficient and depending on the cover, the adhesion is exhibited. Or there is a problem that the peeling force is high and the delivery property of the film in the roll form is deteriorated. The lower limit of this ratio is about 0.003 as a realistic value. As described above, the ratio is calculated in consideration of the width of the sample at the time of measurement. Preferably, it is in the range of 0.01 to 0.18, and 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 blocking resistance and the protective performance of the coating can be improved. When the surface roughness of the release layer is lower than 0.10 μm, the feeding properties of the film when it is in roll form may be deteriorated. When the surface roughness of the release layer is higher than 0.50 μm, the surface irregularities of the release layer may be transferred to the surface of the adhesive layer, and the adhesion may be significantly reduced. At this time, it is more preferable that the surface unevenness of the release layer be a surface having an average surface roughness SRa of 0.25 μm or more and 0.45 μm or less.
In addition, three-dimensional average surface roughness SRa of the mold release layer surface means the average roughness in the center plane at the time of approximating a surface roughness curve by a sine curve, and it can measure it with a surface roughness measuring apparatus etc.

(Adhesive film)
It is preferable that the thickness of the adhesion layer of the adhesion film of this invention is one to 30 micrometer. When the thickness of the adhesive layer is less than 1 μm, stable film formation by co-extrusion becomes difficult, and when it is 30 μm or more, the film becomes disadvantageous in cost.
At this time, in the case of increasing the adhesive strength, 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 cover tends to be large. The thickness of the adhesive layer is preferably 2 μm to 20 μm, more preferably 3 μm to 15 μm, and particularly preferably 4 μm to 10 μm.

  The thickness of the base material layer of the pressure-sensitive 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 layer is less than 5 μm, the feeling of stiffness is weakened, and when it is attached to a cover as a protective film, wrinkles etc. are easily included, and there is a problem that sufficient adhesive strength can not be obtained. If it is above, it will be a disadvantageous film in terms of cost.

  It is preferable that the thickness of the release layer of the adhesive film of this invention is 1 micrometer or more and less than 30 micrometers. When the thickness of the adhesive film is less than 1 μm, stable film formation by coextrusion becomes difficult, and when it is 30 μm or more, the film becomes disadvantageous in cost. The thickness of the release layer is more preferably 2 μm or more and 20 μm or less, and still more preferably 3 μm or more and 15 μm or less. 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, the handling may be poor, and when it is too thick, the rigidity may be high and the handling may be poor, and the film may be disadvantageous in cost.

  The self-adhesive surface protective film of the present invention is composed of a base layer containing the above resin component, an adhesive layer and a release layer, and the resin constituting each layer is, for example, a uniaxial or biaxial extruder. It is obtained by being fed to a feed block type or multi manifold type T die as it is in a molten state and laminated and extruded with three or more layers. The temperature of the extruder of each layer may be appropriately adjusted in consideration of the molding temperature of the components used in each layer, for example, in the range of 200 ° C. to 260 ° C., in order to bring each layer into a molten state. It is also good. The temperature of the T-die may be similar to the above temperature.

The adhesive film of the present invention is preferably in the form of a roll in terms of handling. The upper limit of the width and the winding length of the film roll is not particularly limited, but in terms of ease of handling, the width is generally 1600 mm or less in general, and the winding length is preferably 5000 m or less at a film thickness of 40 μm. Also, as the winding core, a plastic core or metal core such as 3 inches, 6 inches, 8 inches, etc. can usually be used.
Moreover, it is preferable that it is a film roll wound up with the dimension of length 100 m or more and width 450 mm or more from the suitability of processing.

  The adhesive film of the present invention is a member such as a prism sheet used for optical applications, a synthetic resin plate (for example, for building materials), a stainless steel plate (for example, for building materials), aluminum plate, decorative plywood, steel plate, glass plate To protect the surface of home electric appliances, precision machinery, and automobile bodies at the time of manufacture, to protect them from being damaged when stacked, stored, transported, or transported in the manufacturing process, as well as Can be used to protect from damage during secondary processing (e.g., bending or pressing).

  This application claims the benefit of priority based on Japanese Patent Application No. 2012-223642 filed on October 5, 2012 and Japanese Patent Application No. 2013-069822 filed on March 28, 2013. It is The entire contents of Japanese Patent Application No. 2012-223642 and Japanese Patent Application No. 2013-069822 are incorporated herein by reference.

  The invention will now be further described by way of examples. However, the present invention is not limited to the following examples without departing from the scope of the invention. In addition, the evaluation method of the physical property in a following example and a comparative example is as follows.

(1) Evaluation of adhesiveness It measured by the following method based on JIS-Z-0237 (2000) adhesive tape and adhesive sheet test method.
As a covering, acrylic plate (Mitsubishi Rayon: Acrilite (registered trademark) 3 mm thick) 50 mm x 150 mm, prism sheet (lens part consists of triangular prism, height of triangular prism is 25 μm, width of triangular prism is 50 μm) 50 mm × 150 mm Prepare a test piece of 150 mm in the winding direction at the time of film production, and cut out a 25 mm test piece in the direction orthogonal to that as a rubber strip (a rubber layer with a mass of 2000 g (spring hardness 80 Hs on roller surface, 6 mm thickness) The test piece was crimped onto the covering at a speed of 5 mm / sec using a 45 mm width and a 95 mm diameter (including the rubber layer) coated with. After pressure bonding, one that has been left for 30 minutes in an environment with a temperature of 23 ° C and a relative humidity of 65% is 180 ° at a speed of 300 mm / min using Shimadzu "Autograph (registered trademark)" (AGS-J) The maximum resistance value at the time of peeling was made into adhesive force [cN / 25 mm]. The 180 degree peeling means that the peeling angle of the acrylic plate and the film at the time of measuring the resistance value at the time of peeling is maintained at 180 degrees.
In the case of measurement, prepare a polyester sheet with a thickness of 190 μm and a size of 25 mm × 170 mm as a grip for the measurement sample, and the adhesive film side of the measurement sample where the adhesive film and acrylic plate are crimped It stuck on cellophane tape, and was used as a grip margin at the time of measurement. A schematic view of the measurement sample is shown in FIG. The measurement was performed 3 times for one sample, and the average value was taken as the adhesion of the sample.

(2) MFR measurement of resin It measured based on JIS-K7210.

(3) Measurement of Flexural Modulus of Resin Measurement was performed in accordance with ASTM D747-70.

(4) Measurement of Ethylene Component in Styrene-Based Elastomer About 330 mg of a resin sample was dissolved in deuterated chloroform, and ¹³ C-NMR (manufactured by BRUKER, AVANCE 500) was measured. From the measurement results obtained, the amount of ethylene component in the styrenic elastomer was identified.

(5) Evaluation of peeling force Acrylic plate (Mitsubishi Rayon: Acrelite (registered trademark) 3 mm thick) 50 mm x 150 mm Double-sided adhesive tape (manufactured by Nitto Denko) is attached, and adhesion of test piece to other side of double-sided adhesive tape A test piece of 150 mm (the winding direction at the time of film production) × 50 mm (a direction perpendicular to the winding direction at the time of film production) was pasted so that the surface came.
As a new test piece, a test piece of 150 mm in the winding direction at the time of film production and 40 mm in the direction perpendicular thereto is cut out, and the release surface of the test piece attached to the adhesive surface and acrylic plate via double-sided adhesive tape. Of a rubber roll (spring hardness of 80 hs on the surface of the roll, covered with a rubber layer with a thickness of 6 mm, with a width of 45 mm, a diameter of 95 mm including a rubber layer) of 5 mm / The mold release surface and the test piece were crimped by making one reciprocation at a speed of seconds. After pressure bonding, a load of 60 kg was applied to a total area of 4000 mm ² of 100 mm in the winding direction and 100 mm in the winding direction, 40 mm in the direction perpendicular thereto, and cooled to 23 ° C. after standing for 24 hours under an environment of 40 ° C. and 65% relative humidity Peeling force was evaluated by peeling 180 degrees of materials at a speed of 300 mm / min using Shimadzu "Autograph (registered trademark)" (AGS-J).
For measurement, prepare a polyester sheet with a thickness of 190 μm and a size of 40 mm × 170 mm as a grip for the measurement sample, and stick it on the end of the 150 mm × 40 mm test piece with a cellophane tape with a width of 15 mm. It was the grip of the occasion. The measurement made the average value of the resistance value at the time of peeling off from 40 mm to 60 mm in the crimped part 100 mm of the test piece as the peeling force [cN / 40 mm] of the test piece. The measurement was carried out three times, and the average value was taken as the final peeling force.

(6) Calculate the maximum adhesive strength to the acrylic plate in consideration of the width of the sample in the ratio measurement when taking the peeling force between the release layer and the adhesive layer as the numerator and the denominator. Specifically, the value obtained by multiplying the value of the peeling force in the above (5) by 25/40 is taken as the molecule.

(7) Payout property from a roll After obtaining a 550 mm wide, 500 m wound film wound body with a slit, it was stored in a rolled state for 7 days under a light shielding environment of temperature 23 ° C. and humidity 75%. With respect to this storage roll, the film end was hand-held and pulled immediately after being rewound 300 m on another plastic core (diameter 9 cm), and was rewound 3 m. It was visually checked whether there was partial elongation or deformation in the film upon unwinding. Those with no partial elongation or deformation were evaluated as ○ (good), and those with partial elongation or deformation were regarded as x (defect).

Example 1
(Preparation of base layer)
100% by mass of a homopolypropylene resin (manufactured by Sumitomo Chemical: FLX 80E4, 230 ° CMFR: 7.5 g / 10 min) was melt-extruded at 240 ° C. with a 90 mm φ single-screw extruder to obtain a substrate layer.
(Preparation of adhesive layer)
Styrene-based elastomer (manufactured by Asahi Kasei Chemicals: Tuftec (registered trademark) H1221, styrene component ratio 12 mass%, ethylene component ratio 18 mass%, 230 ° CMFR: 4.5 g / 10 min) 40 mass% and ethylene · α-olefin coweight Combined (Sumitomo Chemical: CX 3007, 190 ° CMFR: 3.7 g / 10 min, bending elastic modulus: 26 MPa) 50 mass% and petroleum resin (Arakawa Chemical Industries: Alcon (registered trademark) P 125) 10 mass% to 40 mm φ single shaft It melt-extruded at 210 degreeC with the extruder, and was set as the adhesion layer.
(Preparation of mold release layer)
90% by mass of propylene-ethylene block copolymer (manufactured by Japan Polypropylene: BC3HF) and 10% by mass of low density polyethylene resin (manufactured by Ube Industries, Ltd .: R300) were melt-extruded at 230 ° C. .
(Production of film)
Perform lamination extrusion within a three-layer T-die (feed block type, lip width 850 mm, lip gap 1 mm) at 245 ° C while the base material layer, adhesive layer and release layer are each melted in each extruder The The extruded film is pulled to a casting roll at a temperature of 30 ° C. at a speed of 20 m / min and solidified by cooling to a substrate layer thickness of 28 μm, adhesive layer thickness of 6 μm, release layer thickness of 6 μm, film width of 600 mm, film A three-kind three-layer unstretched film with a length of 1100 m was obtained. Furthermore, this film is slitted at a speed of 50 m / min by applying 50 N contact pressure to the film width with a take-up tension of 40 N, and an unstretched film with a film width of 550 mm and a film length of 500 m. Obtained.

Example 2
The base material layer and the release layer were the same as in Example 1, and the adhesive layer was changed to the following contents to obtain an unstretched film of 3 types and 3 layers in the same manner as in Example 1.
(Preparation of adhesive layer)
Styrene-based elastomer (manufactured by Asahi Kasei Chemicals: Tuftec (registered trademark) H1221, styrene component ratio 12 mass%, ethylene component ratio 18 mass%, 230 ° CMFR: 4.5 g / 10 min) 60 mass% and ethylene · α-olefin coweight An adhesive layer was obtained by melt extruding 40% by mass (Sumitomo Chemical: CX 3007, 190 ° CMFR: 3.7 g / 10 min, flexural modulus: 26 MPa) at 210 ° C. with a 40 mm φ single-screw extruder.

[Example 3]
The base material layer and the release layer were the same as in Example 1, and the adhesive layer was changed to the following contents to obtain an unstretched film of 3 types and 3 layers in the same manner as in Example 1.
(Preparation of adhesive layer)
Styrene-based elastomer (manufactured by Asahi Kasei Chemicals: Tuftec (registered trademark) H1221, styrene component ratio 12 mass%, ethylene component ratio 18 mass%, 230 ° CMFR: 4.5 g / 10 min) 40 mass% and ethylene · α-olefin coweight Combined (Sumitomo Chemical: VL100, 190 ° CMFR: 0.8 g / 10 min, flexural modulus: 64 MPa) 50 mass% and petroleum resin (Arakawa Chemical Industries: Alcon (registered trademark) P 125) 10 mass% to 40 mm φ single axis It melt-extruded at 210 degreeC with the extruder, and was set as the adhesion layer.

Example 4
The base material layer and the release layer were the same as in Example 1, and the adhesive layer was changed to the following contents to obtain an unstretched film of 3 types and 3 layers in the same manner as in Example 1.
(Preparation of adhesive layer)
Styrene-based elastomer (manufactured by Asahi Kasei Chemicals: Tuftec (registered trademark) H1041, styrene component ratio 30 mass%, ethylene component ratio 49 mass%, 230 ° CMFR: 5.0 g / 10 min) 85 mass% and ethylene · α-olefin coweight Combined (Sumitomo Chemical: CX 3007, 190 ° CMFR: 0.8 g / 10 min, bending elastic modulus: 26 MPa) 5 mass% and petroleum resin (Arakawa Chemical Industries: Alcon (registered trademark) P 125) 10 mass% to 40 mm φ single shaft It melt-extruded at 210 degreeC with the extruder, and was set as the adhesion layer.

[Example 5]
Example 1 except that the adhesive layer was changed to the following contents as in Example 1, except that the thickness of the base layer was 24 μm, the thickness of the adhesive layer was 10 μm, and the thickness of the release layer was 6 μm. An unstretched film of 3 types and 3 layers was obtained in the same manner as in the above.
(Preparation of adhesive layer)
Styrene-based elastomer (manufactured by Asahi Kasei Chemicals: Tuftec (registered trademark) H1221, styrene component ratio 12 mass%, ethylene component ratio 18 mass%, 230 ° CMFR: 4.5 g / 10 min) 50 mass% and ethylene · α-olefin coweight Combined (Sumitomo Chemical: CX 3007, 190 ° CMFR: 3.7 g / 10 min, bending elastic modulus: 26 MPa) 37 mass% and petroleum resin (Arakawa Chemical Industries: Alcon (registered trademark) P 125) 13 mass% to 40 mm φ single shaft It melt-extruded at 210 degreeC with the extruder, and was set as the adhesion layer.

[Example 6]
Example 1 except that the adhesive layer was changed to the following contents as in Example 1, except that the thickness of the base layer was 30 μm, the thickness of the adhesive layer was 4 μm, and the thickness of the release layer was 6 μm. An unstretched film of 3 types and 3 layers was obtained in the same manner as in the above.
(Preparation of adhesive layer)
Styrene-based elastomer (manufactured by Asahi Kasei Chemicals: Tuftec (registered trademark) H1221, styrene component ratio 12 mass%, ethylene component ratio 18 mass%, 230 ° CMFR: 4.5 g / 10 min) 40 mass% and ethylene · α-olefin coweight Combined (Sumitomo Chemical: CX 3007, 190 ° CMFR: 3.7 g / 10 min, bending modulus: 26 MPa) 55 mass% and petroleum resin (Arakawa Chemical Industries: Alcon (registered trademark) P 125) 5 mass% to 40 mm φ single shaft It melt-extruded at 210 degreeC with the extruder, and was set as the adhesion layer.

Comparative Example 1
The base material layer and the release layer were the same as in Example 1, and the adhesive layer was changed to the following contents to obtain an unstretched film of 3 types and 3 layers in the same manner as in Example 1.
(Preparation of adhesive layer)
Styrene-based elastomer (manufactured by Asahi Kasei Chemicals: Tuftec (registered trademark) H1221, styrene component ratio 12 mass%, ethylene component ratio 18 mass%, 230 ° CMFR: 4.5 g / 10 min) 70 mass% and ethylene · α-olefin coweight Combined (Sumitomo Chemical: CX 3007, 190 ° CMFR: 3.7 g / 10 min, bending elastic modulus: 26 MPa) 20 mass% and petroleum resin (Arakawa Chemical Industries: Alcon (registered trademark) P 125) 10 mass% to 40 mm φ single shaft It melt-extruded at 210 degreeC with the extruder, and was set as the adhesion layer.

Comparative Example 2
The base material layer and the release layer were the same as in Example 1, and the adhesive layer was changed to the following contents to obtain an unstretched film of 3 types and 3 layers in the same manner as in Example 1.
(Preparation of adhesive layer)
Styrene-based elastomer (manufactured by Asahi Kasei Chemicals: Tuftec (registered trademark) H1221, styrene component ratio 12 mass%, ethylene component ratio 18 mass%, 230 ° CMFR: 4.5 g / 10 min) 70 mass% and ethylene · α-olefin coweight Combined (Sumitomo Chemical: VL100, 190 ° CMFR: 0.8 g / 10 min, flexural modulus: 64 MPa) 20 mass% and petroleum resin (Arakawa Chemical Industries: Alcon (registered trademark) P 125) 10 mass% to 40 mm φ single axis It melt-extruded at 210 degreeC with the extruder, and was set as the adhesion layer.

Comparative Example 3
Styrene-based elastomer (manufactured by Asahi Kasei Chemicals: Tuftec (registered trademark) H1221, styrene component ratio 12 mass%, ethylene component ratio 18 mass%, 230 ° CMFR: 4.5 g / 10 min) 20 mass% and ethylene · α-olefin coweight 70% by mass (Sumitomo Chemical: CX 3007, 190 ° CMFR: 3.7 g / 10 min, flexural modulus: 26 MPa) and 10% by mass of petroleum resin (Arakawa Chemical Industries: Alcon (registered trademark) P 125) at 40 mmφ single axis It melt-extruded at 210 degreeC with the extruder, and was set as the adhesion layer.

Comparative Example 4
The base material layer and the release layer were the same as in Example 1, and the adhesive layer was changed to the following contents to obtain an unstretched film of 3 types and 3 layers in the same manner as in Example 1.
(Preparation of adhesive layer)
Styrene elastomer (manufactured by Asahi Kasei Chemicals: Tuftec (registered trademark) H1221, styrene component ratio 12 mass%, ethylene component ratio 18 mass%, 230 ° CMFR: 4.5 g / 10 min) 40 mass% and homopolypropylene (Sumitomo Chemical product: 50% by mass of FLX80E4, 190 ° CMFR: 7.5g / 10min and 10% by mass of petroleum resin (made by Arakawa Chemical Industries, Ltd .: Alcon (registered trademark) P125) by melt extrusion at 210 ° C using a 40 mm single screw extruder It was a layer.

Comparative Example 5
The base material layer and the release layer were the same as in Example 1, and the adhesive layer was changed to the following contents to obtain an unstretched film of 3 types and 3 layers in the same manner as in Example 1.
(Preparation of adhesive layer)
Hydrogenated product of random copolymer of styrene and butadiene (JSR product: Dynaron (registered trademark) 1320 P, styrene component ratio 10 mass%, ethylene component ratio 22 mass%, 230 ° CMFR: 3.5 g / 10 min) 80 mass% And petroleum resin (manufactured by Arakawa Chemical Industries, Ltd .: Alcon (registered trademark) P 125) and 10% by mass ethylene / α-olefin copolymer (manufactured by Sumitomo Chemical: CX 3007, 190 ° CMFR: 3.7 g / 10 min, flexural modulus of elasticity: 26 MPa 10% by mass was melt-extruded at 210 ° C. with a 40 mmφ single-screw extruder to form an adhesive layer.

  The results are shown in Tables 1 and 2.

  As is clear from Table 1, the films obtained in Examples 1 to 6 had practically sufficient adhesiveness when used as a protective film, and the feeding properties when the film was fed out as a roll were also good. .

  On the other hand, the films obtained in Comparative Examples 1, 2 and 5 could not be said to have good feeding properties when the films were fed as rolls. The films obtained in Comparative Examples 3 and 4 did not have sufficient adhesion to the coating. Thus, the films obtained in the comparative examples were all inferior in quality and low in practicality.

Claims (6)

The adhesive layer is laminated on one side of the base material layer made of polypropylene resin and the release layer is laminated on the other side by coextrusion, and the maximum adhesion to acrylic plate is 800cN / 25 mm or more, and the maximum adhesion to acrylic plate The denominator is a ratio of 0.003 to 0.18 when the peeling force between the release layer and the adhesive layer is taken as a numerator.
The resin constituting the adhesive layer contains a styrene-based elastomer, a polyethylene-based resin, and a tackifier resin, and the content of the styrene-based elastomer in the adhesive layer is 35% by mass to 99% by mass, the content of the polyethylene-based resin The amount is 1% by mass to 65% by mass, and the sum of the ethylene component in the styrene elastomer and the polyethylene resin is 35% by mass to 46.7% by mass in the adhesive layer component,
The polyethylene-based resin is at least one selected from the group consisting of low density polyethylene and a copolymer of ethylene and an α-olefin,
The compounding quantity of tackifying resin in the said adhesion layer is 3 mass% or more and 10 mass% or less with respect to 100 mass% of the said adhesion layer components,
The resin constituting the release layer contains a propylene-ethylene block copolymer . Self-adhesive surface protective film characterized in that The resin constituting the release layer further contains a resin incompatible with the propylene-ethylene block copolymer, and the propylene-ethylene block copolymer is incompatible with the propylene-ethylene block copolymer. The self-adhesive surface protection film according to claim 1, wherein a ratio of the propylene-ethylene block copolymer is 90 parts by mass or more to a total of 100 parts by mass of the at least one resin. The self-adhesive surface protection film according to claim 1 or 2 , wherein MFR (190 ° C, 2.16 kgf) of the polyethylene-based resin in the adhesive layer is 0.5 to 8 g / 10 min. The self-adhesive surface protection film according to any one of claims 1 to 3 , wherein MFR (230 ° C, 2.16 kgf) of the styrenic elastomer in the adhesive layer is 0.5 to 8 g / 10 min. The self-adhesive surface protection film according to any one of claims 1 to 4 , wherein MFR (230 ° C, 2.16 kgf) of the polypropylene resin in the base material layer is 1.0 to 15 g / 10 min. The self-adhesive surface protection film according to any one of claims 1 to 5 , wherein the resin used for the release layer is a non-silicone resin.

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