JP6323690B2 - Self-adhesive surface protective film - Google Patents

Description

  The present invention relates to an 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 plate (for example, for building materials), an aluminum plate, a decorative plywood, a steel plate, and a glass plate. , Home appliances, precision machinery, to protect the surface of automobile bodies during manufacturing, to protect articles from being scratched when stacked, stored, transported, transported in the manufacturing process, and articles Can be suitably used for protecting from scratches during secondary processing (for example, bending or pressing).

  Conventionally, adhesive films aimed at protecting the surface of coatings have been used during processing, storage, and transportation of building materials, electrical, electronic products, automobiles, etc. Such adhesive films have good adhesive properties. In addition, after use, each surface must be able to be easily peeled off without being contaminated with an adhesive.

  In recent years, the above-described coverings have been diversified, and there are a large number of coverings having not only smooth covering surfaces but also surface irregularities. Examples of the covering having surface irregularities include a prism type lens portion of a prism sheet used for an optical member. In order to develop a sufficient adhesive force for use on a coated body having surface irregularities such as a prism sheet, the adhesive layer has a high adhesive force so that the adhesive force can be obtained even if the contact area is small. Can be considered.

  In order to increase the adhesive strength of the adhesive layer, it is possible to use a styrene-based elastomer that exhibits high adhesive strength as a main component, but if the adhesive strength of the adhesive layer is increased, the film is stored in a roll state. Then, when the film is subsequently fed out, blocking occurs, causing problems such as partial stretching or deformation of the film. Further, when the blocking is severe, there is a problem in that the feeding sound becomes large when the film is fed and the surrounding working environment is remarkably deteriorated as noise.

  Noise sometimes causes health problems such as sleep problems as well as hearing loss. If the noise exceeds 90 dB, the guidelines for preventing noise disturbances published by the Ministry of Health, Labor and Welfare will impose restrictions on work, such as requiring workers engaged in the work to use soundproofing protective equipment. come.

  When creating an adhesive film by melt-extrusion of the entire film layer, as a countermeasure, fluorine-based resin, silicon-based resin (see, for example, Patent Documents 1 and 2) or saturated fatty acid bisamide is used for the base layer. (For example, refer to Patent Document 3 etc.) has been studied, but any of these resins may migrate to the adhesive layer when stored in a roll state, and the adhesive strength is reduced. Concerns such as letting it go and contaminating the covering cannot be wiped off.

  In addition, the use of a styrene-based elastomer for the adhesive layer has also been studied (see, for example, Patent Documents 4, 5, 6, etc.). Neither of the above-mentioned problems in feeding the film was satisfied.

JP 2008-81589 A JP 2008-308559 A Japanese Patent No. 4565058 Japanese Patent Application Laid-Open No. 08-73822 Japanese Patent Laid-Open No. 2007-161882 JP 2007-332329 A

  The problem to be solved by the present invention is that the adhesive film is stored in a roll state while showing strong adhesive strength to the covering and can be used for various coverings. It is an object of the present invention to provide a self-adhesive surface protective film which is less prone to problems such as partial elongation or deformation and has excellent processability of the film.

As a result of intensive studies, the present inventors have found that the above problems can be solved, and have reached the present invention.
That is, the present invention is obtained by laminating an adhesive layer on one side of a base material layer made of a polypropylene resin and a release layer on the opposite side by coextrusion, and the adhesive layer has a styrene content of 5 to 40% by weight. Hydrogenation of a random copolymer of styrene and butadiene having a styrene content of 40 to 70% by weight, and a styrene elastomer A which is a hydrogenated block copolymer of a styrene polymer block and a butadiene polymer block A styrene-based elastomer B, and the weight ratio of the styrene-based elastomer A to the sum of these two types of styrene-based elastomers is 5% by weight or more and 80% by weight or less, and the sum of these two types of styrene-based elastomers A self-adhesive surface protective film, wherein 5 to 25 parts by weight of a tackifier resin is mixed with 100 parts by weight.

  According to the present invention, the adhesive film is stored in a roll state and can be used for various coverings while exhibiting strong adhesive strength against the covering. It is possible to obtain a self-adhesive surface protective film which hardly causes problems such as stretching and deformation and has excellent processability of the film.

  In this case, it is preferable that the peeling force of the pressure-sensitive adhesive surface of the pressure-sensitive adhesive film to the mold release surface is 200 cN / 40 mm or less at 23 ° C.

  In this case, it is preferable that the delivery sound when a film roll having a film width of 550 mm and a winding length of 1000 m is fed out at a speed of 20 m / min for 300 m is less than 90 dB.

  In this case, the MFR (230 ° C., 2.16 Kgf) of the styrene-based elastomer A or the styrene-based elastomer B in the previous adhesive layer is preferably 0.5 to 8 g / 10 minutes.

  Furthermore, in this case, it is preferable that the MFR of the polypropylene resin in the base material layer is (230 ° C., 2.16 Kgf) is 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-silicon resin.

  The pressure-sensitive adhesive film according to the present invention exhibits a strong adhesive force to the covering and can be used for various coverings. However, when the pressure-sensitive adhesive film is stored in a roll state and then fed out, the film is partially The film has the advantage that the film is not easily stretched or deformed, and is excellent in processability of the film.

It is a schematic diagram of a measurement material. It is a schematic diagram of a measurement. It is a schematic diagram of a measurement.

The present invention is a styrene having a pressure-sensitive adhesive layer laminated on one side of a base material layer made of polypropylene resin and a release layer laminated on the opposite side by coextrusion, and the pressure-sensitive adhesive layer has a styrene content of 5 to 40% by weight. Hydrogenated product of styrene-butadiene random copolymer having a styrene content of 40 to 70% by weight and a styrene-based elastomer A which is a hydrogenated product of a block copolymer of a polymer block and a butadiene polymer block And the weight ratio of the styrene elastomer A to the sum of these two kinds of styrene elastomers is 5% by weight or more and 80% by weight or less, and the sum of these two kinds of styrene elastomers, It is a self-adhesive surface protective film characterized in that 5 to 25 parts by weight of a tackifier resin is mixed with 100 parts by weight.
Hereinafter, embodiments of the pressure-sensitive adhesive film of the present invention will be described.

(Adhesive layer)
As a resin constituting the pressure-sensitive adhesive layer of the present invention, when a film stored in a roll state is unfolded while exhibiting high adhesive strength, problems such as partial elongation or deformation of the film are less likely to occur. It is necessary to use at least two kinds of styrene elastomers and tackifying resins. In order to control the adhesive force, an olefin resin such as a polyethylene resin, a tackifier resin, a softening agent, polystyrene, and the like can be mixed as necessary.

One of the two types of styrene elastomers used is a hydrogenated block copolymer of styrene polymer block and butadiene polymer block (hereinafter referred to as styrene elastomer A). Examples thereof include an ABA block polymer such as butadiene-styrene and an AB block polymer such as a styrene-butadiene copolymer.
The other of the two types of styrene elastomers used is a hydrogenated product of a random copolymer of styrene and butadiene (hereinafter referred to as styrene elastomer B), which is a styrene random copolymer such as styrene-butadiene rubber. Examples include hydrogenated polymers.
The melt flow rate (MFR: 230 ° C., 2.16 Kgf) of the styrene-based elastomer A or styrene-based elastomer B to be used is preferably in the range of 0.5 to 8 g / 10 minutes in terms of film forming properties, and is preferably 2.0 to The range of 7.0 g / 10 min is more preferable.

The total amount of the styrene-based elastomer in the adhesive layer is such that the weight ratio with respect to the entire resin composition constituting the adhesive layer is 60% by weight or more, in order to express high adhesive strength and roll out of the film from the roll state. It is preferable that it is below wt%.
If the total amount of the styrene-based elastomer is less than 60% by weight, the adhesive strength is lowered, and it becomes difficult to obtain the required adhesive strength. The total amount of styrenic elastomer in the adhesive layer is preferably in the range of 65% by weight to 95% by weight.
As the styrene elastomer at this time, a styrene elastomer other than the styrene elastomer A and the styrene elastomer B may be used.

The adhesive layer is composed of a styrene elastomer A which is a hydrogenated product of a block copolymer of a styrene polymer block and a butadiene polymer block, and a styrene elastomer B which is a hydrogenated product of a random copolymer of styrene and butadiene. The weight ratio of the styrene elastomer A which is a hydrogenated product of a copolymer of a styrene polymer block and a butadiene polymer block to the total amount of the styrene elastomer A and the styrene elastomer B is preferable. Is preferably 5% by weight or more.
When the weight ratio of the styrene elastomer A, which is a hydrogenated block copolymer of a styrene polymer block and a butadiene polymer block, is less than 5% by weight, the adhesive strength is reduced, and the required adhesive strength is obtained. It becomes difficult.
The weight ratio of the styrene elastomer A to the total amount of the styrene elastomer A and the styrene elastomer B is more preferably 8% by weight or more, and particularly preferably 20% by weight or more.

On the other hand, the weight ratio of styrene elastomer A, which is a hydrogenated block copolymer of styrene polymer block and butadiene polymer block, to the total amount of styrene elastomer A and styrene elastomer B is 80% by weight or less. preferable.
When the weight ratio of the styrene-based elastomer A to the total amount of the styrene-based elastomer A and the styrene-based elastomer B exceeds 80% by weight, the roll-out property of the film from the roll state may not be sufficiently exhibited.
The weight ratio of the styrene elastomer A is more preferably 60% by weight or less, further preferably 50% by weight or less, and particularly preferably 40% by weight or less.

The weight ratio of the styrene component of the styrene elastomer A which is a hydrogenated block copolymer of a styrene polymer block and a butadiene polymer block is preferably 5% by weight or more and 40% by weight or less.
If the weight ratio is less than 5% by weight, granulation at the time of preparing the resin becomes difficult. If the weight ratio exceeds 40% by weight, a blend of styrene elastomer B, which is a hydrogenated product of a random copolymer of styrene and butadiene. If it performs, adhesive force will fall and it will become difficult to obtain the adhesive force required.
The styrene component weight ratio of the styrene elastomer A, which is a hydrogenated block copolymer of a styrene polymer block and a butadiene polymer block, is preferably in the range of 5 wt% or more and 20 wt% or less. Is more preferable, and the range of 5 wt% or more and 13 wt% or less is most preferable, and the adhesive force is more easily developed.

On the other hand, the weight ratio of the styrene component in the styrene elastomer B, which is a hydrogenated product of a random copolymer of styrene and butadiene, is preferably 40% by weight or more and 70% by weight or less.
When the weight ratio of the styrene component in the styrene elastomer B is less than 40% by weight, a blend of the styrene elastomer A which is a hydrogenated product of a block copolymer of a styrene polymer block and a butadiene polymer block is used. If it is carried out, the roll-out property of the film from the roll state may not be sufficiently exhibited, and if it exceeds 70% by weight, the adhesive strength is lowered and it becomes difficult to obtain the required adhesive strength.
The styrene component of the styrene elastomer B, which is a hydrogenated product of a random copolymer of styrene and butadiene, is preferably in the range of 45% by weight to 65% by weight.

  Examples of the tackifying resin include aliphatic hydrocarbon resins, aromatic hydrocarbon resins, terpene resins, coumarone / indene resins, styrene resins, and rosin resins. 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 risk of causing material transfer from the adhesive layer to the adherend or heavy peeling, while the molecular weight is large. Since there exists a tendency for it to become scarce in the improvement effect of adhesive force, the number average molecular weight of tackifying resin has a preferable thing of about 1000-100,000. The number average molecular weight can be measured by gel permeation chromatography or the like.

The weight ratio of the content of the tackifying resin in the resin composition constituting the adhesive layer is in the range of 5% by weight to 25% by weight with respect to the total amount of the styrene elastomer A and the styrene elastomer B.
When the content of the tackifying resin exceeds 25% by weight with respect to the total amount of the styrene-based elastomer A and the styrene-based elastomer B, the melt viscosity becomes extremely low because the molecular weight of the tackifying resin is low, and a T-die or the like was used. When co-extrusion film formation is performed, not only is it difficult to laminate with a base material layer mainly composed of a polypropylene resin, but the adhesive layer becomes sticky, and it is difficult to improve the film feedability from the roll state. Tend to be.
Moreover, even if it mix | blends that content of tackifying resin is less than 5 weight% with respect to the total amount of the styrene-type elastomer A and the styrene-type elastomer B, it does not contribute to the adhesive force change of an adhesion layer, and the required adhesive force May not be obtained.
The content of the tackifying resin is preferably 6% by weight or more and 24% by weight or less, more preferably 7% by weight or more and 23% by weight or less, based on 100 parts by weight of the sum of the two types of styrene elastomers.

  In the case where the melt viscosity tends to decrease due to the addition of the tackifying resin in the adhesive layer, the base material can be added by adding about 1 wt% to 15 wt% of the polystyrene resin with respect to the entire resin composition constituting the adhesive layer. The difference in melt viscosity between the layer and the adhesive layer can be improved, and lamination can be facilitated. The amount of polystyrene resin at that time is preferably 5% by weight or more and 10% by weight or less.

Moreover, by adding about 0.1 to 15% by weight of the softening agent with respect to the entire resin composition constituting the adhesive layer, the adhesive force to the coated body having surface irregularities is easily developed.
Examples of the softening agent include low molecular weight diene polymers, polyisobutylene, hydrogenated polyisoprene, hydrogenated polybutadiene and derivatives thereof, and polybutene. The molecular weight of the softening agent is not particularly limited and can be set appropriately, but if the molecular weight is small, there is a risk of causing material transfer from the adhesive layer to the adherend or heavy peeling, while the molecular weight is large. The number average molecular weight of the softening agent is preferably about 1,000 to 100,000 because the effect of improving the adhesive force tends to be poor. The number average molecular weight can be measured by the same method as in the case of the tackifier resin.

  Further, the tackifying resin and softening agent used in the adhesive layer are liquids or powders depending on the type, and there are things that contaminate the extruder during extrusion. Such problems can be improved by using a tackifier resin or softener as a masterbatch with a polyethylene resin or polyolefin resin, so that the tackifier resin or softener can be a masterbatch with a polyethylene resin or polyolefin resin. It is more preferable to use it after making it.

  The pressure-sensitive adhesive film of the present invention may contain a polyolefin resin in order to improve the feeding property. Polyolefin-based resin is not particularly limited, crystalline polypropylene, copolymer of propylene and a small amount of α-olefin, low density polyethylene, high density polyethylene, copolymer of ethylene and a small amount of α olefin, ethylene and vinyl acetate and And the like. Among them, many polyethylene resins have a low elastic modulus and can be suitably used because they are easy to improve the feeding property without reducing the adhesive force.

The content of the polyolefin-based resin in the adhesive layer is preferably in the range of 1% by weight to 30% by weight with respect to the entire resin composition constituting the adhesive layer.
If the content of the polyolefin resin exceeds 30% by weight, the adhesive strength may be lowered depending on the resin used, and sufficient adhesive strength may not be obtained.
The content of the polyolefin resin in the adhesive layer is preferably mixed at a ratio of 25% by weight or less.

The pressure-sensitive adhesive film of the present invention can contain known additives as necessary. For example, a lubricant, an antiblocking agent, a heat stabilizer, an antioxidant, an antistatic agent, a light resistance agent, an impact resistance improvement agent and the like may be contained.
However, these components have a relatively low molecular weight, and may bleed out to the surface of the adhesive layer to reduce the adhesive strength of the adhesive layer. Therefore, when using an additive, it is preferable 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. After the surface of the adhesive layer is washed with an organic solvent that does not erode the resin constituting the adhesive layer such as ethanol, the organic solvent is removed from the cleaning solution with an evaporator, and the residue obtained by weighing the residue is washed. It was obtained by dividing by the surface area of the layer surface. Here, if the residue is present in an amount of 1 mg / m ² or more, foreign matter exists between the surface of the adhesive layer and the adherend surface, which reduces the contact area and decreases the van der Waals force. It is lowered and not preferable. In the case of adding an additive, it is necessary to select an additive such as a polymer type or to examine the addition amount and the addition method so that there is no transfer or transfer to the adhesive layer.

The adhesive strength of the pressure-sensitive adhesive film of the present invention is preferably in the range of 150 to 800 cN / 25 mm with respect to the acrylic plate at 23 ° C. in consideration of use in various coverings. The acrylic board used for this evaluation uses what contains methacrylic resin 88% or more. When the adhesive strength is less than 150 cN / 25 mm, turning may occur when protecting depending on the covering, and the function as a protective film may not be carried. On the other hand, when the adhesive strength exceeds 800 cN / 25 mm, there is a possibility that the film cannot be smoothly peeled when the film is peeled from the covering.
Further, at 23 ° C., the range of 2 to 20 cN / 25 mm with respect to the prism sheet is preferable in consideration of use. When the adhesive strength is less than 2 cN / 25 mm, turning or the like occurs when protecting, and the function as a protective film cannot be carried. On the other hand, when the adhesive strength exceeds 20 cN / 25 mm, there is a possibility that the film cannot be smoothly peeled when the film is peeled off. The adhesive force can be appropriately set by changing the resin composition, thickness, etc. of the adhesive layer.

  The working sound of the pressure-sensitive adhesive film of the present invention is preferably less than 90 dB when a film roll having a film width of 550 mm and a winding length of 1000 m is fed out by 300 m at a speed of 20 m / min. If the delivery sound exceeds 90 dB, it is not preferable because it is necessary to wear a soundproof protective equipment. More preferably, it is less than 88 dB, More preferably, it is less than 85 dB. On the other hand, although the delivery sound has never been small, since it is a film having an adhesive layer that adheres strongly to the acrylic plate, a practical value of about 70 dB is the lower limit of the delivery sound.

(Base material layer)
The pressure-sensitive adhesive film of the present invention requires a base material layer mainly composed of a polypropylene-based resin. The polypropylene-based resin used here includes crystalline polypropylene, random copolymerization of propylene and a small amount of α-olefin, and block copolymerization. More specifically, as a crystalline polypropylene resin, an n-heptane-insoluble isotactic propylene homopolymer used in ordinary extrusion molding or the like or propylene containing 60% by weight or more of propylene And other α-olefin copolymers, and these propylene homopolymers or copolymers of propylene and other α-olefins can be used alone or in admixture.
The base material layer preferably contains 60% by weight or more of propylene units, more preferably 70% by weight or more. If the propylene content is less than 60% by weight, the film may lose a feeling of back and handling may be difficult. In addition, when the propylene content is less than 50% by weight or a polyethylene resin is used, the film becomes flexible and easily stretched, and problems such as partial stretching or deformation of the film occur when the film is fed out. It becomes easy.
Here, the insolubility of n-heptane indicates safety of the polypropylene as well as the crystallinity of polypropylene. In the present invention, the insolubility of n-heptane (25 ° C., 60 ° It is a preferred embodiment to use one that is compatible with an elution amount of 150 pPm or less (if the operating temperature exceeds 100 ° C., 30 PPm or less) at the time of partial extraction.

As the α-olefin copolymerization component of the copolymer of propylene and other α-olefin, α-olefin having 2 to 8 carbon atoms such as ethylene, 1-butene, 1-pentene, 1-hexene, 4 -C4- or higher α-olefins such as methyl-1-pentene. Here, the copolymer is preferably a random or block copolymer obtained by polymerizing one or more α-olefins exemplified above with propylene. The melt flow rate (MFR: 230 ° C., 2.16 Kgf) of the polypropylene resin used is preferably in the range of 1.0 to 15 g / 10 minutes, more preferably in the range of 2.0 to 10.0 g / 10 minutes. Two or more types of copolymers of propylene and other α-olefins can be mixed and used.
Furthermore, the waste film produced when the film obtained in the present invention is processed into a product can be re-granulated as a recovered raw material and added to the base material layer. By using the recovered raw material, the production cost can be reduced.

(Release layer)
The pressure-sensitive adhesive film of the present invention forms a release layer on the surface opposite to the pressure-sensitive adhesive layer laminated on one side of the base material layer, so that even if the pressure-sensitive adhesive films are stacked, there is little blocking between the pressure-sensitive adhesive films, In particular, when the pressure-sensitive adhesive film is stored in a roll state and then fed out, problems such as partial stretching or deformation of the film hardly occur, and the film has excellent workability. In order to prevent blocking of the adhesive films even when the adhesive films are stacked, it is effective to form surface irregularities on the release layer to reduce the contact area with the adhesive layer.

In order to form such surface irregularities, it is effective to mix an incompatible resin with a polypropylene resin. By doing so, a layer whose surface is rough like a mat can be formed.
Examples of the incompatible resin to be mixed at this time include polyethylene resins and polymethylpentene resins. By using a propylene-ethylene block copolymer as the polypropylene resin, the same effect can be expected without using an incompatible resin.
At this time, the content of the ethylene component in the propylene-ethylene block copolymer is preferably 3 to 18% by weight.
Of course, it is also possible to add incompatible resins such as polyethylene resins and polymethylpentene resins to the propylene-ethylene block copolymer.
The total content of incompatible resins such as polyethylene resins and polymethylpentene resins in the polyolefin resin constituting the release layer is preferably in the range of 3 to 40 wt%.

  As the resin incompatible with the polypropylene resin, an α-olefin (co) polymer having 4 or more carbon atoms such as low density polyethylene and 4-methylpentene-1 (co) polymer is preferably used. In addition, linear low density polyethylene, high density polyethylene, copolymers of ethylene and a small amount of α-olefin, copolymers of ethylene and vinyl acetate, polystyrene, polyester resins, polyamide resins, etc. It is done. In particular, 4-methylpentene-1 (co) polymer not only roughens the surface like a mat, but also improves the peelability by lowering the surface free energy of the film surface.

  The peeling force of the pressure-sensitive adhesive surface of the pressure-sensitive adhesive film of the present application with respect to the release surface is preferably within a range of 250 cN / 40 mm or less at 23 ° C. from the viewpoint of the film payout property when the pressure-sensitive adhesive film is in roll form. If the peeling force exceeds 250 cN / 40 mm, problems such as partial stretching or deformation of the film occur when the film is fed out when the adhesive film is rolled. In addition, the lower limit of the peeling force with respect to the release surface of the pressure-sensitive adhesive surface of the pressure-sensitive adhesive film is about 1 cN / 40 mm, more preferably about 3 cN / 40 mm as a practical value.

In view of the resin composition of the pressure-sensitive adhesive layer of the present invention, it is preferable that the three-dimensional average surface roughness SRa of the release layer surface is 0.10 μm or more and 0.50 μm or less. By doing so, blocking resistance and the protection performance of a covering can be improved. When the surface roughness of the release layer is lower than 0.10 μm, the film feedability when the film 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 adhesive force may be significantly reduced. At this time, the surface unevenness of the release layer is more preferably a surface having an average surface roughness SRa of 0.25 μm or more and 0.45 μm or less.
The three-dimensional average surface roughness SRa of the release layer surface means the average roughness at the center plane when the surface roughness curve is approximated by a sine curve, and can be measured by a surface roughness measuring device or the like.

The thickness of the pressure-sensitive adhesive layer of the present invention is preferably 1 μm or more and less than 30 μm. When the thickness of the adhesive layer is less than 1 μm, stable film formation by coextrusion becomes difficult, and when it is 30 μm or more, a film is disadvantageous in terms of cost.
At this time, when increasing the adhesive strength, it is preferable to increase the thickness in consideration of the viscosity. Increasing the thickness of the adhesive layer tends to increase the contact area with the adherend. 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 present invention is preferably 5 μm or more and less than 100 μm, more preferably 10 μm or more and less than 75 μm, and further preferably 15 μm or more and less than 40 μm. When the thickness of the base material layer is less than 5 μm, there is a problem that the waist feeling is weak, wrinkles etc. are easily formed when pasted to a covering as a protective film, and sufficient adhesive strength cannot be obtained. If it is above, the film is disadvantageous in terms of cost.

The thickness of the release layer of the present invention is preferably 1 μm or more and less than 30 μm. If the thickness of the adhesive film is less than 1 μm, stable film formation by coextrusion becomes difficult, and if it is 30 μm or more, the film is disadvantageous in terms of cost. The thickness of the release layer is preferably 2 μm or more and 20 μm or less, and more preferably 3 μm or more and 15 μm or less.
In addition, it is preferable that the thickness of the self-adhesive surface protective film of this invention is 10 micrometers or more and 150 micrometers or less, More preferably, they are 15 micrometers or more and 120 micrometers or less, More preferably, they are 20 micrometers or more and 100 micrometers or less. If the total thickness of the film is too thin, it may be inferior in handling, and if it is too thick, the rigidity becomes high and handling properties are inferior, and the film may be 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, for example, a single-screw or biaxial extruder. It is obtained by being fed into a feed block type or multi-manifold type T die while being in a molten state and laminated and extruded with three or more layers. The temperature of the extruder of each layer may be adjusted as appropriate in consideration of the molding temperature of the components used in each layer in order to bring each layer into a molten state, for example, adjusted in the range of 200 ° C to 260 ° C. Also good. The temperature of the T die may be the same as the above temperature.

The pressure-sensitive 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 winding length of the film roll is not particularly limited. However, in view of ease of handling, generally, the width is 1600 mm or less, and the winding length is preferably 5000 m or less when the film thickness is 40 μm. Moreover, as a winding core, a plastic core and metal cores, such as 3 inches, 6 inches, and 8 inches, can usually be used.
Moreover, it is preferable that it is the film roll wound up by the dimension of length 100m or more and width 450mm or more from the suitability of a process.

  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 plate (for example, for building materials), an aluminum plate, a decorative plywood, a steel plate, and a glass plate. , Home appliances, precision machinery, to protect the surface of automobile bodies during manufacturing, to protect articles from being scratched when stacked, stored, transported, transported in the manufacturing process, and articles Can be used for protecting from scratches during secondary processing (for example, bending or pressing).

  The following examples further illustrate the invention. However, the present invention is not limited to the following examples without departing from the gist thereof. 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 * adhesive sheet test method.
As an adherend, acrylic plate (Mitsubishi Rayon Co., Ltd .: Acrylite 3 mm thickness) 50 mm × 150 mm, prism sheet (the lens part is composed of a triangular prism, the height of the triangular prism is 25 μm, the width of the triangular prism is 50 μm) 50 mm × 150 mm As a test piece, a test piece of 150 mm in the winding direction at the time of film production and 25 mm in a direction perpendicular thereto is cut out, and a rubber roll having a mass of 2000 g (roller surface spring hardness 80 Hs, thickness 6 mm rubber layer) The adherend and the test piece were reciprocated once at a speed of 5 mm / second and pressure-bonded using a coating having a width of 45 mm and a diameter (including a rubber layer) of 95 mm. After crimping, the sample left for 30 minutes in an environment of a temperature of 23 ° C. and a relative humidity of 65% was peeled 180 degrees at a rate of 300 mm / min using “Autograph” (AGS-J) manufactured by Shimadzu Corporation. The maximum resistance value was defined as the adhesive strength [cN / 25 mm]. 180 degree peeling means holding the peeling angle between the acrylic plate and the film at the time of measuring the resistance value at the time of peeling at 180 degrees.
At the time of measurement, a polyester sheet having a thickness of 190 μm and a size of 25 mm × 170 mm is prepared as a grip margin for the measurement sample, and the width of the paste margin is 15 mm at the end of the measurement sample obtained by pressure-bonding the adhesive film and the acrylic plate. Attached with cellophane tape as a grip for measurement. A schematic diagram of the measurement sample is shown in FIG. The measurement was performed three times for one sample, and the average value was defined as the adhesive strength of the sample.

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

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

(4) Evaluation of Peeling Force Acrylic board (Mitsubishi Rayon Co., Ltd .: Acrylite 3 mm thickness) 50 mm x 150 mm with a double-sided adhesive tape (Nitto Denko Co., Ltd .: No. 535A) attached, 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 so that the adhesive surface of the test piece came to the surface.
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 a direction perpendicular thereto is cut out, and the release surface of the test piece attached to the adhesive surface and the acrylic plate via a double-sided adhesive tape is used. After overlapping, a release surface using a rubber roll having a mass of 2000 g (with a spring hardness of 80 Hs on the roller surface and a width of 45 mm and a diameter (including the rubber layer) of 95 mm covered with a rubber layer having a thickness of 6 mm). The test piece was reciprocated once at a speed of 5 mm / second and pressed.
After crimping, a load of 60 kg was applied to a total area of 4000 mm ² of 100 mm in the winding direction and 40 mm in the direction perpendicular to it, left in an environment of temperature 40 ° C. and relative humidity 65% for 24 hours, and then cooled to 23 ° C. The product was peeled 180 ° at a rate of 300 mm / min using “Autograph” (AGS-J) manufactured by Shimadzu Corporation. At the time of measurement, a polyester sheet having a thickness of 190 μm and a size of 40 mm × 170 mm is prepared as a grip allowance for the measurement sample, and is attached to the end of a test piece of 150 mm × 40 mm with a cellophane tape with a width of 15 mm of paste. It was the time to grab. In the measurement, the average resistance value when peeling from 40 mm to 60 mm out of the 100 mm crimping portion of the test piece was defined as the peel strength [cN / 40 mm] of the test piece. The measurement was carried out three times, and the average value was taken as the final peel force.

(5) Feeding sound from roll The feeding sound when a film roll having a film width of 550 mm and a winding length of 1000 m was fed 300 m at a speed of 20 m / min was measured. The sound to be delivered is a sound level meter (NL-20, NL-20), the microphone is pointed directly below, 100 mm above the film roll and film peeling point, and La value at a position 50 mm away from the end of the film roll. (A characteristic) was measured. A schematic diagram of the measurement is shown in FIGS. The measurement was carried out for 30 seconds, and the average value was taken as the delivery sound from the roll.

[Example 1]
(Creation of base material layer)
100% by weight 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. with a 90 mmφ single screw extruder to obtain a base material layer.
(Creation of adhesive layer)
Hydrogenated block copolymer of styrene polymer block and butadiene polymer block (Asahi Kasei Chemicals: Tuftec H1221, styrene component ratio 12% by weight, 230 ° C. MFR: 4.5 g / 10 min) 30% by weight and styrene Hydrogenated product of random copolymer of butadiene and butadiene (manufactured by Asahi Kasei Chemicals: SOE L606, styrene component ratio 46% by weight, MFR: 2.9 g / 10 min) and petroleum resin (manufactured by Arakawa Chemical: 15% by weight of Alcon P125) was melt extruded at 210 ° C. with a 40 mmφ single-screw extruder to form an adhesive layer.
(Creation of release layer)
90% by weight of propylene-ethylene block copolymer (manufactured by Nippon Polypropylene: BC3HF) and 10% by weight of low density polyethylene resin (manufactured by Ube Industries: R300) were melt extruded at 230 ° C. with a 65 mmφ single screw extruder to form a release layer. .
(Create film)
Lamination extrusion is performed in a 245 ° C three-layer T die (feed block type, lip width 850 mm, lip gap 1 mm) with the base material layer, adhesive layer, and release layer melted in each extruder. It was. The extruded film is taken to a casting roll at a temperature of 30 ° C. at a rate of 20 m / min, cooled and solidified, and the substrate layer thickness is 28 μm, the adhesive layer thickness is 6 μm, the release layer thickness is 6 μm, the film width is 600 mm, and the film length. A three-kind three-layer unstretched film having a length of 1100 m was obtained. Further, the film was slit at a slitting speed of 50 m / min, a take-up tension of 40 N, and a rubber roll with a contact pressure of 50 N with respect to the film width to obtain an unstretched film having a film width of 550 mm and a film length of 1000 m.

[Example 2]
The base material layer and the release layer were the same as in Example 1, but the adhesive layer was changed to the following content, and a three-kind three-layer unstretched film was obtained by the same production method as in Example 1.
(Creation of adhesive layer)
Hydrogenated block copolymer of styrene polymer block and butadiene polymer block (Asahi Kasei Chemicals: Tuftec H1221, styrene component ratio 12 wt%, 230 ° C. MFR: 4.5 g / 10 min) 10 wt% and styrene Hydrogenated product of random copolymer of butadiene and butadiene (manufactured by Asahi Kasei Chemicals: SOE L606, styrene component ratio 46% by weight, MFR: 2.9 g / 10 min) and petroleum resin (manufactured by Arakawa Chemical: 10% by weight of Alcon P125) was melt extruded at 210 ° C. with a 40 mmφ single screw extruder to form an adhesive layer.

[Example 3]
The base material layer and the release layer were the same as in Example 1, but the adhesive layer was changed to the following content, and a three-kind three-layer unstretched film was obtained by the same production method as in Example 1.
(Creation of adhesive layer)
Hydrogenated block copolymer of styrene polymer block and butadiene polymer block (Asahi Kasei Chemicals: Tuftec H1221, styrene component ratio 12% by weight, 230 ° C. MFR: 4.5 g / 10 min) 5% by weight and styrene Hydrogenated product of random copolymer of butadiene and butadiene (manufactured by Asahi Kasei Chemicals: SOE L606, styrene component ratio 46% by weight, MFR: 2.9 g / 10 min) and petroleum resin (manufactured by Arakawa Chemical: Alcon P125) 10% by weight and ethylene-α-olefin copolymer (Sumitomo Chemical Co., Ltd .: CX3007, 190 ° C. MFR: 3.7 g / 10 min) 5% were melt-extruded at 210 ° C. with a 40 mmφ single screw extruder, and the adhesive layer It was.

[Example 4]
The base material layer and the release layer were the same as in Example 1, but the adhesive layer was changed to the following content, and a three-kind three-layer unstretched film was obtained by the same production method as in Example 1.
(Creation of adhesive layer)
Hydrogenated block copolymer of styrene polymer block and butadiene polymer block (Asahi Kasei Chemicals: Tuftec H1221, styrene component ratio 12% by weight, 230 ° C. MFR: 4.5 g / 10 min) 20% by weight and styrene Hydrogenated product of random copolymer of butadiene and butadiene (manufactured by Asahi Kasei Chemicals: SOE L606, styrene component ratio 46% by weight, MFR: 2.9 g / 10 min) and petroleum resin (manufactured by Arakawa Chemical: Alcon P125) 10% by weight and ethylene-α-olefin copolymer (Sumitomo Chemical Co., Ltd .: CX3007, 190 ° C. MFR: 3.7 g / 10 min) 20% were melt extruded at 210 ° C. with a 40 mmφ single screw extruder, and the adhesive layer It was.

[Comparative Example 1]
The base material layer and the release layer were the same as in Example 1, but the adhesive layer was changed to the following content, and a three-kind three-layer unstretched film was obtained by the same production method as in Example 1.
(Creation of adhesive layer)
Hydrogenated block copolymer of styrene polymer block and butadiene polymer block (Asahi Kasei Chemicals: Tuftec H1221, styrene component ratio 12% by weight, 230 ° C. MFR: 4.5 g / 10 min) 30% by weight and styrene Hydrogenated product of random copolymer of butadiene and butadiene (manufactured by JSR: Dynalon 1320P, styrene component ratio 10 wt%, 230 ° C. MFR: 3.5 g / 10 min) 55 wt% and petroleum resin (Arakawa Chemical: Alcon P125) 15 The adhesive was melt-extruded at 210 ° C. by a 40 mmφ single screw extruder to form an adhesive layer.

[Comparative Example 2]
The base material layer and the release layer were the same as in Example 1, but the adhesive layer was changed to the following content, and a three-kind three-layer unstretched film was obtained by the same production method as in Example 1.
(Creation of adhesive layer)
Hydrogenated block copolymer of styrene polymer block and butadiene polymer block (Asahi Kasei Chemicals: Tuftec H1221, styrene component ratio 12 wt%, 230 ° C. MFR: 4.5 g / 10 min) 10 wt% and styrene Hydrogenated product of random copolymer of butadiene and butadiene (manufactured by JSR: Dynalon 1320P, styrene component ratio 10 wt%, 230 ° C. MFR: 3.5 g / 10 min) 80 wt% and petroleum resin (Arakawa Chemical: Alcon P125) 10 The adhesive was melt-extruded at 210 ° C. by a 40 mmφ single screw extruder to form an adhesive layer.

[Comparative Example 3]
The base material layer and the release layer were the same as in Example 1, but the adhesive layer was changed to the following content, and a three-kind three-layer unstretched film was obtained by the same production method as in Example 1.
(Creation of adhesive layer)
Hydrogenated product of random copolymer of styrene and butadiene (manufactured by Asahi Kasei Chemicals: SOE L606, styrene component ratio 46% by weight, MFR: 2.9 g / 10 min) and petroleum resin (Arakawa Chemical) Manufactured by: Alcon P125) 10% by weight was melt extruded at 210 ° C. with a 40 mmφ single screw extruder to form an adhesive layer.

[Comparative Example 4]
The base material layer and the release layer were the same as in Example 1, but the adhesive layer was changed to the following content, and a three-kind three-layer unstretched film was obtained by the same production method as in Example 1.
(Creation of adhesive layer)
Hydrogenated block copolymer of styrene polymer block and butadiene polymer block (Asahi Kasei Chemicals: Tuftec H1221, styrene component ratio 12% by weight, 230 ° C. MFR: 4.5 g / 10 min) 70% by weight and styrene Hydrogenated product of random copolymer of butadiene and butadiene (manufactured by Asahi Kasei Chemicals: SOE L606, styrene component ratio 46% by weight, MFR: 2.9 g / 10 min) and petroleum resin (manufactured by Arakawa Chemical: 10% by weight of Alcon P125) 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 Tables 1 and 2, the films obtained in Examples 1 to 4 have a practically sufficient adhesive force when used as a protective film, and the feeding property when the film is fed as a roll is also good. Met.

  On the other hand, the films obtained in Comparative Examples 1 and 2 and 4 had a large sound when the film was fed out as a roll, and it could not be said that the feeding property was good. The film obtained in Comparative Example 3 could not be said to have sufficient adhesion to the covering. Thus, all the films obtained in the comparative examples were inferior in quality and low in practicality.

Claims (6)

  A styrenic polymer block in which 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 opposite side by coextrusion, and the adhesive layer has a styrene content of 5 to 40% by weight. Styrene elastomer A which is a hydrogenated block copolymer of styrene and butadiene polymer block, and a styrene based hydrogenated random copolymer of styrene and butadiene having a styrene content of 40 to 70% by weight Elastomer B is contained, and the weight ratio of the styrene elastomer A to the sum of these two styrene elastomers is 5% by weight or more and 80% by weight or less, and the sum of these two styrene elastomers is 100 parts by weight. A self-adhesive surface protective film, wherein 5 to 25 parts by weight of a tackifying resin is mixed.   The self-adhesive surface protective film according to claim 1, wherein the peel strength of the pressure-sensitive adhesive surface to the release surface is 250 cN / 40 mm or less at 23 ° C.   The self-adhesive surface protective film according to claim 1, wherein a payout sound is less than 90 dB when a film roll having a film width of 550 mm and a winding length of 1000 m is fed out at a speed of 20 m / min for 300 m.   The self-adhesion according to any one of claims 1 to 3, wherein the MFR (230 ° C, 2.16Kgf) of the styrene-based elastomer A or the styrene-based elastomer B in the previous adhesion layer is 0.5 to 8 g / 10 min. Polypropylene film.   The self-adhesive polypropylene film according to claim 1, 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 polypropylene film according to any one of claims 1 to 5, wherein the resin used for the release layer is a non-silicon resin.