WO2014054701A1

WO2014054701A1 - Self-adhesive surface protection film

Info

Publication number: WO2014054701A1
Application number: PCT/JP2013/076839
Authority: WO
Inventors: 茂知山本; 大木　祐和; 松田　明
Original assignee: 東洋紡株式会社
Priority date: 2012-10-05
Filing date: 2013-10-02
Publication date: 2014-04-10
Also published as: JPWO2014054701A1; TW201418132A; JP6508383B2; JP2018127637A; TWI607945B

Abstract

　Provided is a self-adhesive surface protection film which exhibits strong adhesion to a body to be covered, with which the adhesive film is stored in a rolled state while being usable with various bodies to be covered, which is not susceptible to problems such as the film partially stretching or deforming when being drawn out from the rolled state, which is unlikely to negatively impact the working environment because not too much noise is made when drawing out the film, and which has excellent film workability.　The self-adhesive surface protection film is characterized by: being formed by using co-extrusion to layer an adhesive layer on one surface of a substrate layer and a release layer on the opposite surface thereof, said substrate layer comprising a polypropylene resin; the maximum adhesion to an acrylic sheet being at least 800cN/25mm; and the sound from the film being drawn out being less than 90db when 300m of a film roll having a film width of 550mm and a roll length of 1000m is drawn out at a speed of 20m/min.

Description

Self-adhesive surface protective film

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 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 not only those having a smooth covering surface but also many having 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. In addition, when the blocking is severe, there is a problem 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.

Conventionally, an adhesive film excellent in adhesive force and roll-out property from a roll state has been obtained by applying an adhesive layer and a release layer on a substrate film. However, these films have the problem of complicated use of solvents and production processes in which environmental impacts are a concern. In recent years, adhesive films produced by melt-extrusion of all layers of the film have been actively developed. It became so. *

When producing an adhesive film by melt-extrusion of the entire film layer, as the above-mentioned measures, a fluororesin, a silicone-based resin (for example, see Patent Documents 1 and 2, etc.) (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. There is a concern that it may cause contamination or contamination of the coating.

In addition, addition of a polyethylene-based resin to the adhesive layer has also been studied (see, for example, Patent Documents 4 and 5). In either case, the adhesive force to the prism and the film are stored in a roll state, and then the film Both of the above-mentioned problems when paying out were not satisfied.

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

The problem to be solved by the present invention shows a strong adhesive force to the covering, and can be used for various coverings, while storing the adhesive film in a roll state, and then paying out the film, To provide a self-adhesive surface protective film that is unlikely to cause problems such as partial stretching or deformation of the film, that does not deteriorate the working environment because the feed-out sound does not become excessive, and that is excellent in workability of the film. It is in.

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 comprises a base material layer made of a polypropylene resin having a pressure-sensitive adhesive layer on one side and a release layer on the other side by co-extrusion, and has a maximum adhesive strength to an acrylic plate of 800 cN / 25 mm or more. The present invention relates to a self-adhesive surface protective film characterized by having a delivery sound of less than 90 dB when a film roll having a width of 550 mm and a winding length of 1000 m is fed out at a speed of 20 m / min for 300 m.

According to the present invention, the adhesive film has a strong adhesive force to the covering and can be used for various coverings. The self-adhesive surface protective film can be obtained which is difficult to cause problems such as stretching or deforming, and that the working environment is hardly deteriorated because the payout sound does not become too large, and that the workability of the film is excellent.

In this case, the resin constituting the adhesive layer includes at least a styrene elastomer and a polyethylene resin, and the content of the styrene elastomer in the adhesive layer is 35% by mass to 99% by mass, and the polyethylene resin is contained. The amount is preferably 1% by mass or more and 65% by mass or less, and the sum of the ethylene component and the polyethylene resin in the styrene elastomer is preferably 35% by mass or more and less than 70% by mass in the adhesive layer component.

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

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

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

In this case, the resin used for the release layer is preferably a non-silicone 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 In particular, there is an advantage that problems such as stretching and deformation are unlikely to occur, the feeding sound does not become too large, the working environment is unlikely to deteriorate, and the film processing suitability is excellent.

It is a schematic diagram of the measurement sample of adhesive force. It is explanatory drawing of the measuring method of a delivery sound. It is explanatory drawing of the measuring method of a delivery sound.

In the present invention, an adhesive layer is laminated on one side of a base material layer made of a polypropylene resin, and a release layer is laminated on the opposite side by coextrusion, and the maximum adhesive force to an acrylic plate is 800 cN / 25 mm or more, and the film width Is a self-adhesive surface protective film (adhesive film) characterized in that a delivery sound when a film roll having a roll length of 550 mm and a winding length of 1000 m is fed out by 300 m at a speed of 20 m / min is less than 90 dB.
Hereinafter, embodiments of the adhesive film of the present invention will be described in detail.

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 the acrylic plate at 23 ° C. in view of use in various coatings. The acrylic board used for this evaluation uses what contains methacrylic resin 88 mass% or more. When the adhesive strength is less than 800 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 1200 cN / 25 mm, there is a possibility that the film cannot be smoothly peeled when the film is peeled from the covering.
Further, it is preferable that the adhesive strength with respect to the prism sheet is in a range of 2 to 20 cN / 25 mm at 23 ° C. in consideration of the 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 feeding 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 at a speed of 20 m / min and less than 90 dB, considering the working environment. If the delivery sound is 90 dB or more, it is not preferable because it is necessary to wear a soundproofing protector. More preferably, it is 88 dB or less, More preferably, it is 85 dB or less. 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 resin. Examples of the polypropylene resin used here include crystalline polypropylene, random copolymers of propylene and a small amount of α-olefin, and blocks. More specifically, as a crystalline polypropylene resin, it contains n-heptane-insoluble isotactic propylene homopolymer or propylene in an amount of 60% by mass or more, which is used in ordinary extrusion molding. And a copolymer of propylene and another α-olefin, and this propylene homopolymer or a copolymer of propylene and another α-olefin can be used alone or in combination.
The base material layer preferably contains 60% by mass or more of propylene units, more preferably 70% by mass or more. When the propylene unit is less than 60% by mass, the film loses its sensation and may be difficult to handle. 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 stretched, and the film partially stretches or deforms when the film is fed out. Is more likely to occur.
Here, the insolubility of n-heptane is indicative of the crystallinity of polypropylene and at the same time indicates safety. In the present invention, n-heptane insolubility (at 25 ° C., 60 ° C. according to Ministry of Health and Welfare Notification No. 20 in February 1982). It is a preferred embodiment to use one that is compatible with an elution amount of 150 ppm or less (30 ppm or less when the operating temperature exceeds 100 ° C.)).

The α-olefin copolymerization component of the copolymer of propylene and other α-olefins includes α-olefins 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 of the 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, and more preferably in the range of 2.0 to 10.0 g / 10 minutes. Further, two or more kinds 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.

(Adhesive layer)
As the resin constituting the adhesive layer of the present invention, it is preferable to use a styrene-based elastomer in order to develop a high adhesive force. Moreover, in order to express the adhesiveness and the roll-out property of the film from the roll state, it is preferable to add a polyethylene resin. Furthermore, by adding a polyethylene-based resin, it is possible to reduce the peeling force from the pressure-sensitive adhesive side to the release surface while maintaining the pressure-sensitive adhesive force with the covering. For controlling the adhesive strength, polyolefin resins other than polyethylene resins, tackifier resins, softeners, polystyrene, and the like can be mixed as necessary.

Styrenic elastomers are ABA type block polymers such as styrene-butadiene-styrene, AB type block polymers such as styrene-butadiene copolymers, and random co-polymerization of styrene polymer blocks with styrene and butadiene. Examples thereof include a hydrogenated product such as a block copolymer with a combined block, and a hydrogenated product of a styrene random copolymer such as styrene-butadiene rubber.

Examples of the polyethylene resin include low density polyethylene and a copolymer of ethylene and α-olefin. Among these, low-density polyethylene, especially linear low-density polyethylene called LLDPE, and ultra-low-density polyethylene called VLDPE reduce the peel strength of the film from the roll state while maintaining the adhesive strength. It is further preferable to improve the feeding property. These are those in which a short chain branch is introduced into an ethylene chain by copolymerizing an α-olefin, and flexibility can be imparted to the polyethylene resin depending on the type and copolymerization amount of the α-olefin. The α-olefin is not particularly limited, and examples thereof include 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, and 1-octene.

The amount of the styrenic elastomer in the adhesive layer is preferably 35% by mass or more and 99% by mass or less in order to reduce the expression of high adhesive force and the peel strength of the film from the roll state and to express the feeding property. It is. If it is less than 35% by mass, the adhesive strength is lowered and it is difficult to obtain the required adhesive strength. The amount of 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 reduce the expression of high adhesive force and the peeling force of the film from the roll state and to express the feeding property. It is. When the amount of the polyethylene resin in the adhesive layer exceeds 65% by mass, the adhesive strength is lowered, 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 and the polyethylene resin in the styrene elastomer 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-based resin is 70% by mass or more in the adhesive layer component, the adhesive strength is lowered and sufficient adhesive strength cannot be obtained. If 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 on the release layer is increased. 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 styrene elastomer to be used is preferably in the range of 0.5 to 8 g / 10 minutes, and 2.0 to 7.0 g / 10 minutes in terms of film forming properties. The range of is more preferable.
The melt flow rate (MFR: 190 ° C., 2.16 kgf) of the polyethylene resin used is preferably in the range of 0.5 to 8 g / 10 minutes, more preferably in the range of 0.8 to 7.0 g / 10 minutes. By making it the said range, it becomes easy to perform the film-forming which made the thickness of each layer uniform.

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 producing a 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 elastomer is more preferably in the range of 10% by mass to 30% by mass. On the other hand, the ethylene component in the styrenic elastomer is easily mixed with the polyethylene resin when the polyethylene resin is added. It seems to be easy to grow. Therefore, the ethylene component in the styrene-based elastomer is desirably 15% by mass or more and 70% by mass or less. Moreover, since it is thought that the ethylene component in a styrene-type elastomer has contributed greatly to adhesive force expression, when it exceeds 70 mass%, when a polyethylene-type resin is added on the following conditions, it will become difficult to reduce adhesive force. There is a tendency.

Moreover, it is preferable that the ethylene component in a polyethylene-type resin is 70 mass% or more. The ethylene component of the polyethylene resin is more preferably 75% by mass or more, and still more preferably 80% by mass or more. Moreover, 98 mass% or less is preferable, as for the ethylene component of a polyethylene-type resin, More preferably, it is 96 mass% or less, More preferably, it is 95 mass% or less. When the ethylene component in the polyethylene-based resin is 70% by mass or more, the effect of improving the drawing property of the film from the roll state tends to be greater. Examples of the resin in which the ethylene component in the polyethylene resin is 70% by mass or more include CX3007 and VL100 manufactured by Sumitomo Chemical.
Incidentally, the component other than the ethylene component in the polyethylene resin is preferably less than 30% by mass, more preferably 25% by mass or less.

The density of the polyethylene resin is preferably 850 to 920 kg / m ³ , more preferably 860 to 910 kg / m ³ , and most preferably 880 to 906 kg / m ³ . By making it the said range, it becomes easy to make favorable adhesiveness and feeding property compatible.

The flexural modulus of the polyethylene resin is desirably 10 MPa or more and less than 90 MPa. When it is 10 MPa or more, the film feedability from the roll state is further improved, and when it is less than 90 MPa, the adhesive strength is further improved. The flexural modulus of the polyethylene resin is more preferably in the range of 15 to 80 MPa, still more preferably in the range of 20 to 70 MPa.

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

Examples of the tackifier resin include petroleum resins, aliphatic hydrocarbon resins, alicyclic hydrocarbon resins, aromatic hydrocarbon resins, terpene resins, coumarone / indene resins, styrene resins, rosin resins, and the like. The molecular weight of the tackifying resin is not particularly limited and can be set as appropriate.However, if the molecular weight is small, there is a risk of causing material transfer from the adhesive layer to the coated body or heavy peeling, while the molecular weight is large. The number-average molecular weight of the tackifying resin is preferably about 1,000 to 100,000 because it tends to be poor in the effect of improving the adhesive force. The number average molecular weight can be measured by gel permeation chromatography or the like.

The amount of tackifying resin in the adhesive layer is preferably in the range of 3% by weight to 20% by weight with respect to 100% by weight of the adhesive layer component. If the compounding amount of the tackifying resin is 20% by mass or more, the melt viscosity becomes extremely low because the molecular weight of the tackifying resin is low, and the main component is a polypropylene resin when performing coextrusion film formation using a T die or the like. In addition to the difficulty of lamination with the base material layer, the adhesive layer becomes sticky, and the film feedability from the roll state tends to be difficult to improve. The blending amount of the tackifying resin is more preferably 5% by mass or more and 15% by mass or less.

If the melt viscosity tends to decrease due to the addition of tackifying resin in the adhesive layer, the difference in melt viscosity between the base material layer and the adhesive layer can be achieved by adding about 1% to 15% by weight of polystyrene resin. Can be improved to facilitate lamination. The blending amount of the polystyrene resin is more preferably 3% by mass or more and 12% by mass or less, and further preferably 5% by mass or more and 10% by mass or less.

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. However, if the molecular weight is small, there is a risk of causing material transfer from the adhesive layer to the coated body or heavy peeling, etc. The number average molecular weight of the softening agent is preferably about 1,000 to 100,000 because it tends to be poor in the effect of improving force. The number average molecular weight can be measured by the same method as in the case of the tackifier resin.

Also, 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 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 an additive is used, the low molecular weight substance on the surface of the adhesive layer is preferably less than 1 mg / m ² . Here, the measurement of the low molecular weight substance on the surface of the adhesive layer was carried out by the following procedure. The adhesive layer surface is washed with an organic solvent that does not corrode the resin constituting the adhesive layer, such as ethanol, and after removing the organic solvent from the cleaning solution with an evaporator, the residue is weighed and the obtained numerical value 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 is present between the surface of the adhesive layer and the surface of the coated body, which reduces the contact area and decreases the van der Waals force. Is not preferable. When adding an additive, it is necessary to select an additive such as a polymer type, or to examine the amount and method of addition, so that there is no migration or transfer to the adhesive layer surface. .

(Release layer)
The pressure-sensitive adhesive film of the present invention forms a release layer made of a polypropylene-based resin that is a non-silicone resin on the surface opposite to the pressure-sensitive adhesive layer laminated on one side of the base material layer. Even if it piles up, blocking between adhesive films decreases. In particular, when the 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 processability. 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 the surface irregularities as described above, 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. 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 an incompatible resin to the propylene-ethylene block copolymer.

As the resin incompatible with the polypropylene resin, α-olefin (co) polymers having 4 or more carbon atoms such as low density polyethylene and 4-methylpentene-1 (co) polymer are preferably used. Other examples include 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, and the like. 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.

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 may be deteriorated when the film is in roll form. If 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.

(Adhesive film)
The thickness of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive film of the present invention is preferably 1 μm or more and less than 30 μm. When the thickness of the adhesive layer is less than 1 μm, 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 covering. 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 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 further preferably 15 μm or more and 55 μm or less. 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 pressure-sensitive adhesive film 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 more preferably 2 μm or more and 20 μm or less, and further 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 appropriately adjusted 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, it may be 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, but 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. In order to protect the surface of home appliances, precision machinery, and automobile bodies during production, to protect articles from being stacked, stored, transported, protected from scratches when transported in the manufacturing process, and It can be used to protect an article from scratches during secondary processing (for example, bending or pressing).

This application claims the benefit of priority based on Japanese Patent Application No. 2012-223623 filed on October 5, 2012 and Japanese Patent Application No. 2013-069821 filed on March 28, 2013 To do. The entire contents of the above Japanese Patent Application No. 2012-223623 and the above Japanese Patent Application No. 2013-069821 are incorporated herein by reference.

Next, the present invention will be further described with reference to examples. 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 was measured by the following method in accordance with JIS-Z-0237 (2000) Adhesive Tape / Adhesive Sheet Test Method.
As a covering, acrylic plate (Mitsubishi Rayon: Acrylite (registered trademark) 3 mm thick) 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 roller having a mass of 2000 g (roller surface spring hardness 80 Hs, thickness 6 mm rubber layer) The test piece was pressure-bonded on the covering body by reciprocating once at a speed of 5 mm / second using a 45 mm width and a diameter (including a rubber layer) of 95 mm. After crimping, the sample left for 30 minutes in an environment with a temperature of 23 ° C. and a relative humidity of 65% is 180 degrees at a speed of 300 mm / min using “Autograph (registered trademark)” (AGS-J) manufactured by Shimadzu Corporation. The maximum resistance value at the time of peeling was defined as 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 adhesive film and the acrylic plate are bonded to the end of the measurement film on which the adhesive film is bonded with a width of 15 mm. 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 Measurement was performed according to JIS-K7210.

(3) Measurement of elastic 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 obtained measurement results, the amount of ethylene component in the styrene-based elastomer was identified.

(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. A sound level meter (Lion Co., Ltd., NL-20) was used as the delivery sound, the microphone was pointed directly below, 100 mm directly 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]
(Preparation of base material layer)
100% by mass of a homopolypropylene resin (manufactured by Sumitomo Chemical Co., Ltd .: FLX80E4, 230 ° C. MFR: 7.5 g / 10 min) was melt-extruded at 240 ° C. with a 90 mmφ single screw extruder to obtain a base material layer.
(Preparation of adhesive layer)
Styrenic elastomer (Asahi Kasei Chemicals: Tuftec (registered trademark) H1221, styrene component ratio 12% by mass, ethylene component ratio 18% by mass, 230 ° C. MFR: 4.5 g / 10 min) 40% by mass and ethylene / α-olefin copolymer weight Combined (Sumitomo Chemical: CX3007, 190 ° C. MFR: 3.7 g / 10 min, flexural modulus: 26 MPa) 50% by mass and petroleum resin (Arakawa Chemical Industries: Alcon (registered trademark) P125) 10% by mass 40 mmφ uniaxial It was melt-extruded at 210 ° C. with an extruder to form an adhesive layer.
(Production of release layer)
90% by mass of propylene-ethylene block copolymer (manufactured by Nippon Polypropylene: BC3HF) and 10% by mass of low density polyethylene resin (manufactured by Ube Industries: R300) were melt extruded at 250 ° C. with a 65 mmφ single screw extruder to form a release layer. .
(Production of film)
While the base material layer, the adhesive layer, and the release layer were melted in each extruder, lamination extrusion was performed in a three-layer T die (feed block type, lip width 850 mm, lip gap 1 mm) at 245 ° C. . The extruded film is taken to a casting roll at a temperature of 30 ° C. at a rate of 20 m / min, and cooled and solidified. 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, the film A three-kind three-layer unstretched film having a length of 1100 m was obtained. Further, this film was slit at a rate of 50 m / min by applying a contact pressure of 50 N to the film width with a rubber roll, and this film was slit at a speed of 50 m / min, whereby an unstretched film having a film width of 550 mm and a film length of 1000 m was obtained. Obtained.

[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.
(Preparation of adhesive layer)
Styrene elastomer (Asahi Kasei Chemicals: Tuftec (registered trademark) H1221, styrene component ratio 12% by mass, ethylene component ratio 18% by mass, 230 ° C. MFR: 4.5 g / 10 min) 60% by mass and ethylene / α-olefin copolymer 40% by mass of coalesced (manufactured by Sumitomo Chemical Co., Ltd .: CX3007, 190 ° C. MFR: 3.7 g / 10 min, flexural modulus: 26 MPa) was melt extruded at 210 ° C. with a 40 mmφ single screw extruder to obtain 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.
(Preparation of adhesive layer)
Styrenic elastomer (Asahi Kasei Chemicals: Tuftec (registered trademark) H1221, styrene component ratio 12% by mass, ethylene component ratio 18% by mass, 230 ° C. MFR: 4.5 g / 10 min) 40% by mass and ethylene / α-olefin copolymer weight Combined (Sumitomo Chemical: VL100, 190 ° C. MFR: 0.8 g / 10 min, flexural modulus: 64 MPa) 50% by mass and petroleum resin (Arakawa Chemical Industries: Alcon (registered trademark) P125) 10% by mass 40 mmφ uniaxial It was melt-extruded at 210 ° C. with an extruder to form an adhesive layer.

[Example 4]
With the base material layer and the release layer remaining in Example 1, 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 Example 1.
(Preparation of adhesive layer)
Styrene elastomer (Asahi Kasei Chemicals: Tuftec (registered trademark) H1041, styrene component ratio 30% by mass, ethylene component ratio 49% by mass, 230 ° C. MFR: 5.0 g / 10 min) 85% by mass and ethylene / α-olefin copolymer Combined (Sumitomo Chemical: CX3007, 190 ° C. MFR: 0.8 g / 10 min, flexural modulus: 26 MPa) 5 mass% and petroleum resin (Arakawa Chemical Industries: Alcon (registered trademark) P125) 10 mass% 40 mmφ uniaxial It was melt-extruded at 210 ° C. with an extruder to form an adhesive layer.

[Example 5]
Example 1 except that the adhesive layer was changed to the following contents while the base material layer and the release layer were the same as in Example 1, the base material layer thickness was 24 μm, the adhesive layer thickness was 10 μm, and the release layer thickness was 6 μm. Three types and three layers of unstretched films were obtained by the same production method.
(Preparation of adhesive layer)
Styrenic elastomer (Asahi Kasei Chemicals: Tuftec (registered trademark) H1221, styrene component ratio 12% by mass, ethylene component ratio 18% by mass, 230 ° C. MFR: 4.5 g / 10 min) 50% by mass and ethylene / α-olefin copolymer weight Combined (Sumitomo Chemical: CX3007, 190 ° C. MFR: 3.7 g / 10 min, flexural modulus: 26 MPa) 37% by mass and petroleum resin (Arakawa Chemical Industries: Alcon (registered trademark) P125) 13% by mass 40 mmφ uniaxial It was melt-extruded at 210 ° C. with an extruder to form an adhesive layer.

[Example 6]
Example 1 except that the adhesive layer was changed to the following contents while the base material layer and the release layer were the same as those in Example 1, the base material layer thickness was 30 μm, the adhesive layer thickness was 4 μm, and the release layer thickness was 6 μm. Three types and three layers of unstretched films were obtained by the same production method.
(Preparation of adhesive layer)
Styrenic elastomer (Asahi Kasei Chemicals: Tuftec (registered trademark) H1221, styrene component ratio 12% by mass, ethylene component ratio 18% by mass, 230 ° C. MFR: 4.5 g / 10 min) 40% by mass and ethylene / α-olefin copolymer weight Combined (Sumitomo Chemical: CX3007, 190 ° C. MFR: 3.7 g / 10 min, flexural modulus: 26 MPa) 55% by mass and petroleum resin (Arakawa Chemical Industries: Alcon (registered trademark) P125) 5% by mass 40 mmφ uniaxial It was melt-extruded at 210 ° C. with an extruder to form an adhesive layer.

[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.
(Preparation of adhesive layer)
70% by mass of styrene elastomer (Asahi Kasei Chemicals: Tuftec (registered trademark) H1221, styrene component ratio 12% by mass, ethylene component ratio 18% by mass, 230 ° C. MFR: 4.5 g / 10 min) and ethylene / α-olefin co-polymer Combined (Sumitomo Chemical: CX3007, 190 ° C. MFR: 3.7 g / 10 min, flexural modulus: 26 MPa) 20% by mass and petroleum resin (Arakawa Chemical Industries: Alcon (registered trademark) P125) 10% by mass 40 mmφ uniaxial It was melt-extruded at 210 ° C. with an 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.
(Preparation of adhesive layer)
70% by mass of styrene elastomer (Asahi Kasei Chemicals: Tuftec (registered trademark) H1221, styrene component ratio 12% by mass, ethylene component ratio 18% by mass, 230 ° C. MFR: 4.5 g / 10 min) and ethylene / α-olefin co-polymer Combined (Sumitomo Chemical: VL100, 190 ° C. MFR: 0.8 g / 10 min, flexural modulus: 64 MPa) 20% by mass and petroleum resin (Arakawa Chemical Industries: Alcon (registered trademark) P125) 10% by mass 40 mmφ uniaxial It was melt-extruded at 210 ° C. with an extruder to form an adhesive layer.

[Comparative Example 3]
20% by mass of styrene elastomer (Asahi Kasei Chemicals: Tuftec (registered trademark) H1221, 12% by mass of styrene component, 18% by mass of ethylene component, 230 ° C. MFR: 4.5 g / 10 min) and ethylene / α-olefin copolymer Combined (Sumitomo Chemical: CX3007, 190 ° C. MFR: 3.7 g / 10 min, flexural modulus: 26 MPa) 70% by mass and petroleum resin (Arakawa Chemical Industries: Alcon (registered trademark) P125) 10% by mass 40 mmφ uniaxial It was melt-extruded at 210 ° C. with an 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.
(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 ° C. MFR: 4.5 g / 10 min) 40 mass% and homopolypropylene (manufactured by Sumitomo Chemical: FLX80E4, 190 ° C. MFR: 7.5 g / 10 min) 50% by mass and petroleum resin (Arakawa Chemical Industries: Alcon (registered trademark) P125) 10% by mass were melt-extruded at 210 ° C. with a 40 mmφ single screw extruder and adhered. Layered.

[Comparative Example 5]
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.
(Preparation of adhesive layer)
Hydrogenated random copolymer of styrene and butadiene (manufactured by JSR: Dynalon (registered trademark) 1320P, styrene component ratio 10 mass%, ethylene component ratio 22 mass%, 230 ° C. MFR: 3.5 g / 10 min) 80 mass% And 10% by mass of petroleum resin (Arakawa Chemical Industries: Alcon (registered trademark) P125) and ethylene / α-olefin copolymer (Sumitomo Chemical: CX3007, 190 ° C. MFR: 3.7 g / 10 min, flexural modulus: 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 apparent from Table 1, the films obtained in Examples 1 to 6 had practically sufficient adhesive strength when used as a protective film, and the delivery sound when the film was delivered as a roll was also good. .

On the other hand, in the films obtained in Comparative Examples 1, 2, and 5, the delivery sound when the film was delivered as a roll exceeded 90 dB and was not good. The films obtained in Comparative Examples 3 and 4 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

A pressure-sensitive adhesive layer is laminated on one side of a base material layer made of a polypropylene resin, and a release layer is laminated on the opposite side by co-extrusion. The maximum adhesive force to an acrylic plate is 800 cN / 25 mm or more, but the film width is 550 mm, A self-adhesive surface protective film, wherein a film roll having a winding length of 1000 m is fed out by 300 m at a speed of 20 m / min, and a delivery sound is less than 90 dB.
The resin constituting the adhesive layer contains at least a styrene elastomer and a polyethylene resin, the content of the styrene elastomer in the adhesive layer is 35% by mass to 99% by mass, and the content of the polyethylene resin is 1% by mass. The self-adhesive surface protective film according to claim 1, wherein the sum of the ethylene component and the polyethylene resin in the styrene elastomer is 35% by mass or more and less than 70% by mass in the adhesive layer component. .
3. The self-adhesive surface protective film according to claim 2, wherein the MFR (190 ° C., 2.16 kgf) of the polyethylene resin in the adhesive layer is 0.5 to 8 g / 10 minutes.
The self-adhesive surface protective film according to claim 2 or 3, wherein the MFR (230 ° C, 2.16 kgf) of the styrene-based elastomer in the adhesive layer is 0.5 to 8 g / 10 min.
The self-adhesive surface protective film according to any one of claims 1 to 4, wherein the MFR (230 ° C, 2.16 kgf) of the polypropylene resin in the base material layer is 1.0 to 15 g / 10 min.
6. The self-adhesive surface protective film according to claim 1, wherein the resin used for the release layer is a non-silicone resin.