KR20100046267A - Surface protection film - Google Patents

Abstract

The invention relates to a surface protection film which is to be applied to the surfaces of building materials, various resin plates for use in electrical and electronic fields, glass plates, metal plates and so on for the purpose of protecting the adherends from scratching, contamination or the like in storage, transportation, or post-processing. A surface protection film which little stains the surface of an adherend and is excellent in fabricability is provided by using, as the main resin component constituting the pressure-sensitive adhesive layer of the film, a resin blend which comprises an amorphous α-olefin polymer and a linear low-density polyethylene at a specific ratio or which comprises an amorphous α-olefin polymer, a linear low-density polyethylene, and a crystalline ethylene/α-olefin copolymer at a specific ratio.

Description

Surface protection film {SURFACE PROTECTION FILM}

This invention adheres to the surface for the purpose of protecting the surface of various resin plates, glass plates, metal plates, etc. used in building materials, an electrical / electronic field, etc., and damages a to-be-adhered body at the time of storage, transportation, and post-processing. , Surface protection film to protect from contamination. In particular, it is related with the surface protection film which is extremely free from contamination of the to-be-adhered surface after peeling and peeling from the to-be-adhered body after sticking a surface protection film to a to-be-adhered body, and the like. .

As the basic required performance for the surface protective film, the above-mentioned various adherends are excellent in adhesion workability uniformly attached without attracting wrinkles or air, and there is no moxibustion or peeling between storage and transport of the adherends. And the like having a moderate adhesive strength, a small change in the environment during storage of the adherend and a change in the adhesive strength due to post-processing, and being easily peelable, and which do not contaminate the surface of the adherend after peeling.

As a conventional surface protection film, what used the film which consists of polyvinyl chloride resin, polyethylene resin, polypropylene resin, etc. as a base material, and coated adhesives, such as a urethane type, an acryl type, and rubber type, on the single side | surface is known. However, these surface protection films may be inferior in adhesiveness between the film as the base material and the adhesive, or a part of the adhesive may remain on the surface of the adherend when peeled from the adherend due to the low cohesive force of the adhesive itself. There was. Moreover, since the surface protection film which apply | coats an adhesive to a film and manufactures requires the minimum 2 steps of the manufacturing process of the film which is a base material, and the coating process of an adhesive, a manufacturing cost becomes high and a large amount of solvent is used in the coating process of an adhesive. There was a problem that the environmental load is increased because it needs to be removed.

As a method of improving the said problem, the self-adhesive type surface protection film which simultaneously extruded and laminated | stacked and laminated | stacked the film layer and adhesive layer of a base material by the coextrusion lamination method is proposed. As such a surface protection film, for example, as a resin composition for an adhesion layer, using the mixture which has an amorphous olefin copolymer, a crystalline olefin copolymer, and a thermoplastic elastomer, and has a specific property (for example, By using a mixture of an amorphous olefin copolymer, a crystalline olefin polymer and a block copolymer having a crystalline olefin block at a specific ratio (see Patent Document 2, for example). The multilayer film which is excellent in adhesive strength and peeling stability, and is not sticking after peeling is provided.

Furthermore, the inventors of the present invention already have a moderate adhesiveness and heat resistance, and have a small amount of contamination on the surface of the adherend after peeling, and include a base layer mainly composed of a crystalline propylene polymer and an amorphous α-olefin type. The surface protection film which laminated | stacked the adhesion layer which consists of resin which mixed a polymer and a crystalline propylene polymer in a specific ratio was provided (for example, refer patent document 3).

However, when sticking the surface protection film provided by the said patent document 1 or 2 to an acryl plate etc., peeling from an to-be-adhered body might become difficult because of the high initial stage adhesive force. Moreover, depending on a use, after a protective film peels, secondary processing, such as printing, may be given to the surface of resin plates etc. which are to-be-adhered bodies. In the surface protection film which consists of a co-extrusion laminated | multilayer film provided by the said patent document 1 or 2, an extremely small amount of residues due to looseness etc. generate | occur | produce on the surface of a to-be-adhered body after film peeling, and it becomes a factor of a printing defect in such secondary processing There was a problem. Moreover, when mix | blending a styrene-type elastomer with the adhesion layer, after winding up in roll shape, when peeling and using again, the adhesion layer and a base material layer may be in close contact, and it may become difficult to remove, so-called blocking may arise.

Moreover, in the surface protection film provided by patent document 3, although there is no contamination as much as it can visually confirm to the to-be-adhered body surface after peeling, there may be a case which changes the property of the to-be-adhered body surface, especially coating and printing after peeling. In the case of performing secondary processing, the adverse effects were sometimes given.

Patent Document 1: Japanese Patent Application Laid-Open No. 2006-188646

Patent Document 2: Japanese Patent Application Laid-Open No. 2006-257247

Patent Document 3: Japanese Patent Application Laid-Open No. 2007-130872

[Initiation of invention]

[Problem to Solve Invention]

The subject of this invention has moderate adhesiveness and adhesive stability, there is no residue which can be visually confirmed on the surface of a to-be-adhered body after peeling, and there are no traces of unidentifiable traces, and secondary processing aptitudes, such as printing, are favorable, and also roll shape After winding up, it is providing the surface protection film without blocking at the time of unwinding and using again.

[Means for solving the problem]

MEANS TO SOLVE THE PROBLEM As a result of earnestly researching in order to solve the said subject, as a resin used for the adhesion layer of a surface protection film, the resin which mixed an amorphous alpha-olefin type polymer and linear low density polyethylene in a specific ratio, or amorphous By using the? -olefin polymer, a linear low density polyethylene, and a resin in which a crystalline ethylene-?-olefin copolymer is mixed at a specific ratio as a main component, contamination on the surface of the adherend is extremely small, and the secondary workability The improvement was found and the present invention was completed.

That is, this invention is a surface protection film which laminated | stacked the adhesion layer (A) and the base material layer (B), The adhesion layer (A) is 5-50 mass% of an amorphous alpha-olefin type polymer (A1), 50 to 95 mass% of mixed resin of linear low density polyethylene (A2) having a density of 0.880 to 0.938 g / cm ³ , or 5 to 50 mass% of an amorphous α-olefin polymer (A1), and a density of 0.880 to 0.938 40-90 mass% of linear low-density polyethylene (A2) which is g / cm <^3> , and 5-50 mass% of crystalline ethylene-alpha-olefin copolymer (A3) mixed resin as a main component, The surface protection film characterized by the above-mentioned. To provide. In addition, in this invention, having as a main component the specific resin in each layer is prescribed | regulated by this invention among the resin compositions (all containing various additives, the other resin etc. used together as needed) used for the said layer. It means what contains 65 mass% or more of resin or mixed resin made.

[Effects of the Invention]

After sticking to various resin plates, glass plates, metal plates, etc., the surface protection film of this invention does not have a solution which can be visually confirmed on the surface of the to-be-adhered body after peeling, even if it is left to stand for a long time or exposed to high temperature environment, and it cannot be visually confirmed. There is also very little residue. Therefore, the surface protection film of this invention is useful as a film which protects the surfaces of various resin plates, a glass plate, a metal plate, etc., and is especially suitable for the use which performs secondary processing, such as printing, after peeling of a protective film. In addition, when the surface protection film of this invention is wound up in roll shape, when it unwinds and uses again, there is no blocking and it is excellent also in blocking resistance.

Moreover, especially the surface protection film of this invention obtained using an ethylene polymer as a base material layer, in addition to the said performance, when cut-processing the to-be-adhered body in the state in which the surface protection film was stuck to the to-be-adhered body, It also has excellent properties of being cut neatly and not causing appearance defects such as cobwebbing and fluff, and its application field is wide.

BEST MODE FOR CARRYING OUT THE INVENTION [

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail. The surface protection film of this invention is a coextrusion laminated | multilayer film which formed the adhesion layer (A) and the base material layer (B) by the coextrusion lamination method.

The amorphous alpha -olefin polymer (A1) used for the adhesion layer (A) of the surface protection film of this invention is a polymer or copolymer containing the monomeric unit based on the alpha-olefin of C3-C20. In the measurement range of -100 to 200 ° C. of a differential scanning calorimeter (DSC), polymers in which neither the melting peak of the heat of fusion of crystals is 1 J / g or more and the crystallization peak of the heat of crystallization of 1 J / g or more are observed. You may use individually or may use 2 or more types together.

The α-olefin having 3 to 20 carbon atoms may be linear or branched, and for example, propylene, butene-1, pentene-1, hexene-1, heptene-1, octene-1, Nonene-1, decene-1, undecene-1, dodecene-1, tridecene-1, tetradecene-1, pentadecene-1, hexadecene-1, heptadecene-1, octadecene-1, nanodecene Linear α-olefins such as -1 and eicosene-1; And branched α-olefins such as 3-methylbutene-1, 3-methylpentene-1, 4-methylpentene-1, 2-ethyl-1-hexene, 2,2,4-trimethylpentene-1 and the like. have.

The amorphous α-olefin polymer (A1) is preferably a copolymer having two or more types of monomer units based on these α-olefins, a monomer unit based on propylene, and an α- having 4 to 20 carbon atoms. Copolymers having one or more monomer units based on olefins have industrial availability, compatibility with linear low density polyethylene (A2) or crystalline ethylene-α-olefin copolymer (A3) described later, and coextrusion moldability. It is more preferable from a viewpoint of etc., In particular, an amorphous propylene-butene-1 copolymer and an amorphous propylene-ethylene-butene-1 copolymer are the most preferable. In addition, the amorphous α-olefin-based polymer (A1) may have a monomer unit other than the α-olefin. As such a monomeric unit, the monomeric unit based on ethylene, a polyene compound, a cyclic olefin, a vinyl aromatic compound, etc. are mentioned, for example.

As content rate of the monomeric unit based on the propylene in the said amorphous propylene-butene-1 copolymer, 100 mass% of all the monomeric units of an amorphous propylene-butene-1 copolymer from a viewpoint of the heat resistance of the surface protection film obtained improve. When it is referred to, 70 mass% or more is preferable, More preferably, it is 80 mass% or more, More preferably, it is 90 mass% or more.

As a content rate of the monomeric unit based on the propylene in the said amorphous propylene ethylene- butene-1 copolymer, from the viewpoint of improving the heat resistance of the surface protection film obtained, all the monomer units of an amorphous propylene ethylene-butene-1 copolymer If it is 100 mass%, 50 mass% or more is preferable, More preferably, it is 60 mass% or more. In addition, as content rate of the monomeric unit based on ethylene in an amorphous propylene- ethylene- butene-1 copolymer, when all monomer units of an amorphous propylene- ethylene-butene-1 copolymer are 100 mass%, It is preferable that it is 10 mass% or more, More preferably, it is 20 mass% or more. If the content rate of the monomer unit based on ethylene is this range, since the said adhesion layer (B) becomes a comparatively soft thing, even if there are unevenness | corrugation on the surface of a to-be-adhered body, since it adheres closely in the form which follows the unevenness | corrugation, sufficient adhesive force is obtained Lose.

The intrinsic viscosity [?] Of the amorphous α-olefin polymer (A1) is preferably 0.1 to 10.0 dl / g, more preferably 0.7 to 7.0 dl / g. Moreover, it is preferable that the molecular weight distribution (Mw / Mn) represented by the ratio of a weight average molecular weight (Mw) and a number average molecular weight (Mn) is larger than 1 and is 4 or less, and it is more preferable that it is 2-3. When the intrinsic viscosity and molecular weight distribution of the amorphous α-olefin-based polymer (A1) are within this range, heat resistance, transparency, and adhesiveness are improved, and the adherend to which the surface protective film is stuck is stored for a long time, or is exposed to a high temperature environment. Contamination of the adherend due to migration of low molecular weight components in the island-in-water amorphous α-olefin-based polymer (A1) onto the adherend surface can be reduced. In addition, since the amorphous α-olefin polymer (A1) is an olefin polymer, as in the case where the ethylene-vinyl acetate copolymer is used as the resin for the adhesive layer, an increase in the adhesive force over time due to the deterioration of the resin such as deacetic acid is increased. It is possible to maintain a stable adhesive force over a long period of time.

The method for producing the amorphous α-olefin polymer (A1) is not particularly limited, and for example, a metallocene catalyst using a gas phase polymerization method, a solution polymerization method, a slurry polymerization method, a bulk polymerization method, or the like. The method of superposing | polymerizing by this etc. are mentioned. As a more preferable manufacturing method, the manufacturing method disclosed in Unexamined-Japanese-Patent No. 2002-348417 is mentioned.

Resin used for the adhesion layer (A) in the surface protection film of this invention is resin which mixed the said amorphous alpha-olefin polymer (A1) and linear low density polyethylene (A2), or the said amorphous alpha- It is resin which mixed the olefin polymer (A1), linear low density polyethylene (A2), and a crystalline ethylene-alpha-olefin copolymer (A3). By blending the linear low density polyethylene (A2) and the crystalline ethylene-α-olefin copolymer (A3) in the amorphous α-olefin polymer (A1), the surface state of the adherend, the material of the adherend, the use, etc. It can adjust by adhesive force according to a required characteristic, and can reduce the contamination to the to-be-adhered body surface after peeling, regardless of the strength of adhesive force.

The linear low-density polyethylene (A2) has a density in the range will 0.880~0.938g / cm ^3, the density is more preferably in 0.898~0.925g / cm ^3. Moreover, it is preferable that the melt flow rate (MFR, the value measured at 190 degreeC and 21.18N based on JISK7210: 1999) is 0.5-30.0 g / 10min, and it is 2.0-15.0 g / 10min. desirable. If the density and MFR of linear low density polyethylene (A2) are this range, compatibility with the amorphous alpha-olefin type polymer (A1) mentioned above will be favorable, and the film-forming property of a laminated film will improve.

Examples of the crystalline ethylene-α-olefin copolymer (A3) include ethylene-propylene copolymers, ethylene-butene-1 copolymers, and the like, but the ethylene-butene-1 copolymers are readily available industrially and obtain surface protection. It is preferable from a viewpoint that adjustment of the adhesive force of a film becomes easy. As the crystalline ethylene-α-olefin copolymer (A3), the MFR (value measured at 190 ° C. and 21.18 N) is 0.5 to 30.0 g / 10 minutes, and the density is preferably 0.870 to 0.905 g / cm ³ , and more Preferably, the MFR is 2.0 to 15.0 g / 10 min and the density is 0.880 to 0.900 g / cm ³ . If the MFR and density of the crystalline ethylene-α-olefin copolymer (A3) are within this range, compatibility with the above-mentioned amorphous α-olefin polymer (A1) is good, and the film forming property of the laminated film is improved. Moreover, it is more preferable that these resins are the metallocene catalyst system mentioned later with few low molecular weight components from the contamination prevention effect on the surface of a to-be-adhered body. In addition, the crystallinity is a polymer in which either the melting peak of the melting heat of a crystal is 1 J / g or more, and the crystallization peak of 1 J / g or more is observed in the measurement range of -100-200 degreeC of a differential scanning calorimeter (DSC). To say.

When using the mixed resin of an amorphous alpha-olefin type polymer (A1) and linear low-density polyethylene (A2) as a main component in the adhesion layer (A), the compounding ratio is an amorphous alpha-olefin type polymer (A1) It is 5-50 mass%, 50-95 mass% of linear low-density polyethylene (A2), More preferably, it mixes with 5-40 mass% of component (A1), and 60-95 mass% of component (A2). If the blending ratio of the amorphous α-olefin-based polymer (A1) is less than 5% by mass, sufficient adhesive strength cannot be obtained. If it exceeds 50% by mass, the adhesive force is too strong, so that handling of the film becomes difficult. Moreover, by adjusting the compounding ratio of component (A1) and component (A2) in the said range, it becomes easy to adjust to the adhesive force of about 0.05-5.0 N / 25mm according to the adhesive force requested | required.

In addition, when using the resin which mixed amorphous (alpha) -olefin type polymer (A1), linear low-density polyethylene (A2), and crystalline ethylene-alpha-olefin copolymer (A3) for adhesion layer (A) as a main component, the mixing ratio is 5 to 50 wt% non-crystalline α- olefin polymer (A1), a density of 0.880~0.938g / cm ³ of linear low-density polyethylene (A2) 40~90% by weight, crystalline ethylene -α- It is 5-50 mass% of an olefin copolymer (A3), More preferably, it is 5-30 mass% of component (A1), 40-85 mass% of component (A2), and 10-45 mass% of component (A3). By adjusting the compounding ratio of component (A1), component (A2), and component (A3) in the said range, it becomes easy to adjust to the adhesive force of about 0.1-7.0 N / 25mm according to the adhesive force requested | required.

In the present invention, the resin used for the adhesive layer (A) contains the above-described mixed resin as a main component, but other resins may be used in combination within a range that does not lose the effects of the present invention. At this time, as other resin which can be used together, a propylene homopolymer, a propylene- butene-1 copolymer, a propylene-butene-1-ethylene terpolymer, butene-1 homopolymer, styrene-butadiene-styrene, for example Copolymer (SBS), styrene-isoprene-styrene copolymer (SIS), styrene-ethylene-butylene-styrene copolymer (SEBS), styrene-ethylene-propylene-styrene copolymer (SEPS), styrene-butadiene copolymer ( SB), styrene-isoprene copolymer (SI), styrene-ethylene-butylene copolymer (SEB), styrene-butadiene rubber (SBR), styrene-ethylene-butylene-ethylene copolymer (SEBC), and also hydrogens thereof Additives etc. are mentioned.

The method for producing the mixed resin used in the pressure-sensitive adhesive layer (A) of the present invention is not particularly limited, but the co-extrusion lamination method takes into consideration that the amorphous α-olefin polymer (A1) is difficult to handle at room temperature. In order to apply more easily, it is preferable to melt-knead the amorphous α-olefin-based polymer (A1) beforehand by linear low density polyethylene (A2) or other crystalline polymer and the like to form pellets which are easy to handle. .

In addition, as mentioned above, in this invention, what makes a specific resin in each layer a main component is in the resin composition (all containing various additives, other resin etc. used together as needed) used for the said layer. It means that it contains 65 mass% or more of resin or mixed resin prescribed | regulated by this invention, It is preferable that it is 75 mass% or more from the point which becomes easier to express the effect of this invention, and it is especially 85 mass% or more. desirable.

As resin used for the base material layer (B) of the surface protection film of this invention, although it will not specifically limit, if coextrusion with the adhesion layer (A) is possible as a thermoplastic resin, but affinity with the said adhesion layer (A) It is preferable to have an olefin polymer as a main component from a favorable point, and it is especially preferable to have an ethylene polymer (B1) or a crystalline propylene polymer (B2) as a main component.

As said ethylene polymer (B1), low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene etc. are mentioned, for example. These may be used independently, respectively and may be used together. Among these, since heat resistance is favorable, it is preferable to have linear low density polyethylene, medium density polyethylene, or mixed resin of a low density polyethylene and a high density polyethylene as a main component.

When the said ethylene polymer (B1) is used as a base material layer (B), in addition to the antifouling effect on the to-be-adhered body surface after peeling of the main object of this invention, a to-be-adhered body in the state which a surface protection film adhered to the to-be-adhered body. When cut processing, the surface protection film is cut | disconnected neatly, and also favorable cutting property which does not produce appearance defects, such as a slip and a fluff, also expresses.

Moreover, as these ethylene polymers (B1), it is preferable that MFR (value measured at 190 degreeC and 21.18N) is 0.5-30.0 g / 10min since extrusion molding becomes easy, More preferably, MFR is 2.0. It is a thing of -15.0g / 10min. In addition, when these ethylene polymers (B1) have a melting point of 90 to 135 ° C, even if they are exposed to a high temperature environment by drying after being adhered to the adherend, heat molding, or the like, there is little shrinkage of the film. Since peeling, curvature of a to-be-adhered body, etc. can be suppressed, it is preferable, More preferably, melting | fusing point is 105-130 degreeC.

When heat resistance is calculated | required by the surface protection film of this invention, it is preferable to use a crystalline propylene polymer (B2) as resin used for a base material layer (B). Examples of the crystalline propylene polymer (B2) include propylene homopolymers, ethylene-propylene copolymers, propylene-butene-1 copolymers, and propylene-ethylene-butene-1 copolymers. These may be used independently or may use 2 or more types together. Moreover, it is preferable that MFR (value measured by 230 degreeC and 21.18N) of these crystalline polypropylene polymers (B2) is 0.5-30.0 g / 10min, and melting | fusing point is 120-165 degreeC, More preferably, , MFR is 2.0 to 15.0 g / 10 minutes, and the melting point is 125 to 162 ° C. If the MFR and the melting point are within these ranges, the film shrinks even when exposed to a high temperature environment by drying, heat molding, or the like after being adhered to the adherend, so that there is no moxibustion or peeling, no warping occurs in the adherend, and the film formation of the laminated film. It also improves sex. In addition, the crystallinity is a polymer in which either the melting peak of the melting heat of a crystal is 1 J / g or more, and the crystallization peak of 1 J / g or more is observed in the measurement range of -100-200 degreeC of a differential scanning calorimeter (DSC). Say.

Moreover, it is preferable that it is a crystalline propylene polymer (it is also called metallocene catalyst polypropylene) obtained using a metallocene catalyst among the crystalline propylene polymer (B2) used for the said base material layer (B). The metallocene catalyst polypropylene is a polypropylene polymerized using a metallocene catalyst instead of the conventional Ziegler-Natta catalyst. As this metallocene catalyst, for example, a metallocene homogeneous mixed catalyst containing a metallocene compound and an aluminoxane, a metallocene supported catalyst in which a metallocene compound is supported on a particulate carrier, etc. Can be mentioned. The metallocene supported catalyst is disclosed in Japanese Patent Laid-Open No. 5-155931, Japanese Patent Laid-Open No. 8-104691, Japanese Patent Laid-Open No. 8-157515, Japanese Patent Laid-Open No. 8-231621, and the like. Since the metallocene catalyst polypropylene has high uniformity of molecular weight distribution and composition distribution, and there is little content of a low molecular weight component, a low molecular weight component is used by using a metallocene catalyst polypropylene for the base material layer (B) of this invention. It is easy to prevent contamination of the surface of the adherend by the bleed. Further, the metallocene catalyst-based polypropylene may be a propylene homopolymer or a copolymer of propylene with another α-olefin. Examples of the copolymer of propylene with other α-olefins include ethylene-propylene copolymers and the like. Can be.

When using the said crystalline propylene polymer (B2) as said base material layer (B), you may use together the amorphous (alpha) -olefin type polymer (B3) similar to what was mentioned above with respect to the said adhesion layer (A). By using amorphous alpha-olefin type polymer (B3) together, the flexibility of the surface protection film obtained increases, the followability to the adherend surface at the time of sticking of a film improves, and it peels smoothly at the time of peeling. In addition, the amorphous (alpha) -olefin type polymer (B3) used at this time may be the same copolymer as the amorphous (alpha) -olefin type polymer (A1) used for the above-mentioned adhesion layer (A), or may be another copolymer.

When mix | blending an amorphous alpha-olefin type polymer (B3) with a base material layer (B), the compounding ratio of a crystalline propylene polymer (B2) and an amorphous alpha-olefin type polymer (B3) is based on a mass [crystal | crystallization] Propylene-based polymer (B2)]: [amorphous α-olefin-based polymer (B3)] = 70 to 95:30 to 5, more preferably in the range of 80 to 95:20 to 5 Range. If the blending ratio of the crystalline propylene polymer (B2) and the amorphous α-olefin polymer (B3) is within this range, heat resistance can be maintained while providing sufficient flexibility to the surface protective film obtained.

Moreover, you may adjust the flexibility of the surface protection film obtained by using together the said ethylene polymer (B1) and a crystalline propylene polymer (B2) as a base material layer (B). Moreover, the flexibility of the film obtained can also be manufactured by using together an ethylene-methylmethacrylate copolymer (henceforth "EMMA"). As EMMA, the thing of 0.5-30.0 g / 10min of MFR (value measured by 190 degreeC and 21.18N) is preferable, More preferably, MFR is 2.0-15.0 g / 10min. In EMMA, it is preferable that the content rate of the monomeric unit based on methylmethacrylic acid (henceforth "MMA") is 3-30 mass%, More preferably, it is 8-25 mass%. When content of the said MFR and MMA is this range, sufficient flexibility will be provided to the surface protection film obtained, and the film-forming property of a laminated film will improve.

In the base material layer (B), in the case of blending an amorphous α-olefin polymer (B3) with an ethylene polymer (B1) and / or EMMA, in the crystalline propylene polymer (B2), the crystalline propylene polymer The blending ratio of (B2), amorphous α-olefin polymer (B3), ethylene polymer (B1) and / or EMMA is based on mass [crystalline propylene polymer (B2)]: [amorphous α- Olefin type polymer (B3)]: [Ethylene type polymer (B1) and / or EMMA] It is preferable that it is the range of 70-95: 4-29: 1-12, More preferably, the said ratio is 80-95: It is the range of 4-19: 1-5. If the blending ratio is within this range, heat resistance can be maintained while providing sufficient flexibility to the surface protective film obtained.

Although the surface protection film of this invention makes two layers of an adhesion layer (A) and a base material layer (B) essential as mentioned above, Furthermore, in the base material layer (B), the surface which laminated | stacked the adhesion layer (A) The surface layer (C) may be provided on the opposite side of the. Although there is no limitation in particular as resin used for a surface layer (C), It is preferable to have an olefin type polymer as a main component from the point of favorable affinity with the said base material layer (B), and especially an ethylene polymer (C1) or crystalline It is more preferable to use a propylene polymer (C2). In particular, when the main component of the base material layer (B) is an ethylene polymer (B1), ethylene polymer (C1), and when the main component of the base material layer (B) is a crystalline propylene polymer (B2), crystalline propylene. It is more preferable if the polymer (C2) is used as the main component.

As an ethylene polymer (C1) which can be used suitably as a main component of a surface layer (C), the same thing as the ethylene polymer (B1) used as a main component of the said base material layer (B) is mentioned. In addition, by selecting the ethylene polymer (C1) as the main component of the surface layer (C), as in the case where the ethylene polymer (B1) is used as the main component of the base layer (B), the high cutability of the finally obtained surface protection film Expression. Moreover, although the same resin may be used for the said ethylene polymer (B1) used for a base material layer (B), and the ethylene polymer (C1) used for a surface layer (C), you may use another resin.

Among the ethylene polymers (C1) used as main components of the surface layer (C), when low density polyethylene is used, it is easy to modify the surface of the surface layer (C) into a pear-skin type. By making the surface of the surface layer C into the shape of a pear shell, blocking can be reduced even when the adhesive force of the adhesion layer A is designed strongly. Moreover, when high density polyethylene is used together with low density polyethylene, the rigidity of the surface protection film obtained can be raised, and workability, such as sticking and peeling, becomes favorable.

Moreover, even if the mixed resin of the said ethylene polymer (C1) and an ethylene-propylene copolymer is used as a main component of the said surface layer (C), the surface of the surface layer (C) can be modified in a pear-shell form. The ethylene-propylene copolymer may be a resin obtained by copolymerizing ethylene and propylene, and for example, an ethylene-propylene block copolymer obtained by polymerizing ethylene or polymerizing ethylene and propylene in the presence of a propylene homopolymer. Can be mentioned. Among these, ethylene-propylene block copolymers having an ethylene-derived component content of 8 to 20% by mass are preferred, and ethylene-propylene having a content of ethylene-derived components of 10 to 15% by mass because it is easy to form the surface as a pear shell. It is more preferable to use a block copolymer. In addition, the MFR (value measured at 230 ° C. and 21.18 N) of the ethylene-propylene copolymer is preferably in the range of 4 to 12 g / 10 minutes in terms of easy extrusion, and more preferably in the range of 6 to 10 g / 10 minutes. desirable. Similarly, the density of the copolymer is preferably in the range of 0.890 to 0.910 g / cm ^{3 in view} of easy extrusion, and more preferably in the range of 0.895 to 0.905 g / cm ³ . Moreover, even if the said ethylene-propylene copolymer is used alone as a main component of the surface layer (C), since the surface of the surface layer (C) can be modified in the shape of a pear shell, the surface of the surface layer (C) can be used with the resin species used for the base material layer (B). It is preferable to select and use suitably in consideration of chemical conversion.

As a crystalline propylene polymer (C2) which can be used suitably as a main component of a surface layer (C), the same thing as the crystalline propylene polymer (B2) used as a main component of the said base material layer (B) is mentioned. In addition, by selecting the crystalline propylene polymer (C2) as the main component of the surface layer (C), as in the case of using the crystalline propylene polymer (B2) as the main component of the base layer (B), High heat resistance is expressed.

Moreover, as a main component of the surface layer (C), you may mix a crystalline propylene polymer (C2) and the said ethylene-propylene copolymer from an adhesive force level, transparency required, etc., and may adjust the grade of pear shell suitably.

It is preferable that the surface protection film of this invention is 20-120 micrometers in total film thickness. When the thickness of the entire film is within this range, workability such as protective properties, adhesiveness, and adhesion and peeling of the adherend becomes good. Moreover, 3-30 micrometers is preferable and, as for the thickness of the adhesion layer (A), More preferably, it is 5-25 micrometers. If the thickness of the adhesion layer (A) is this range, adhesiveness and the film-forming property of a laminated | multilayer film become favorable. Moreover, when providing the said surface layer (C) in the surface protection film of this invention, 3-30 micrometers is preferable, and, as for the thickness of the surface layer (C), it is 5-20 micrometers more preferably. If the thickness of the surface layer (C) is in this range, heat resistance and film-forming property of a laminated film become favorable.

Although it does not specifically limit as a manufacturing method of the surface protection film of this invention, if it is a coextrusion lamination method, For example, it melts resin used for each resin layer using two or more extruders, and the coextrusion die method and the feed After lamination | stacking in a molten state by co-extrusion methods, such as a block method, the method of processing into a film form using methods, such as an inflation and a T-die chill-roll method, is mentioned. In the case of the T-die chilling method, between the rubber touch roll, the steel belt, and the chill roll, the melt-laminated film may be nipped to cool.

In addition, the surface protection film of this invention may be extended | stretched at least in 1 axial direction. As a stretching method, well-known methods, such as uniaxial stretching of longitudinal or a lateral direction, sequential biaxial stretching, simultaneous biaxial stretching, or tubular biaxial stretching, can be employ | adopted. The stretching step may be inline or offline. As a extending | stretching method of uniaxial stretching, the near-roll stretching method or the rolling method may be sufficient. As a draw ratio of uniaxial stretching, 1.1-80 times are preferable in a longitudinal or transverse direction, More preferably, it is 3-30 times. On the other hand, the draw ratio of biaxial stretching is preferably 1.2 to 70 times in area ratio, more preferably 4 to 6 times in length, 5 to 9 times in width, and 20 to 54 times in area ratio.

In addition, as a extending process of a longitudinal or a lateral direction, it is not necessarily limited to single stage extending | stretching, Multistage extending | stretching may be sufficient. In particular, in longitudinal uniaxial stretching such as longitudinal uniaxial roll stretching and longitudinal monoaxial rolling stretching in sequential biaxial stretching, it is preferable to use multistage stretching in terms of thickness and uniformity of physical properties. In the near roll stretching, any of the flat method and the cross method may be used, but multistage close cross stretching for reducing the width reduction is more preferable. As for extending | stretching temperature, 80 degreeC-160 degreeC is preferable also in any extending | stretching method in the case of uniaxial stretching, and when using tender extending | stretching in uniaxial stretching, 90-165 degreeC is preferable. Moreover, as a more preferable extending | stretching temperature, they are 110-155 degreeC and 120-160 degreeC, respectively. On the other hand, in the case of biaxial stretching, the stretching temperature range similar to the case of uniaxial stretching is also preferable in any method. In addition, you may provide a preheating part before an extending | stretching process, and a heat opening part after an extending | stretching process suitably. In this case, the range of the temperature of a preheating part is 60-140 degreeC, and the temperature of a heat-setting part is 90-160 degreeC.

The surface protection film of this invention is extended | stretched to at least one axial direction, and aims at structural stabilization by heat setting, and also the heat-resistant property by orientation crystallization of resin used for a base material layer (B) and a surface layer (C) Since it improves and the aging change of adhesive force becomes small, it is preferable, and especially when the crystalline propylene polymer is used for a base material layer (B) and / or a surface layer (C), the effect becomes high.

Moreover, you may add coloring agents, such as a lubricating agent, an antiblocking agent, a ultraviolet absorber, a light stabilizer, an antistatic agent, an antifog additive, etc. suitably in the range which does not lose the effect of this invention, The resin layer to add may be added to any layer according to the objective. You may add. As these additives, it is preferable to use various additives for olefinic polymers.

EXAMPLE

An Example and a comparative example are given to the following, and this invention is concretely demonstrated to it.

Synthesis Example 1

[Synthesis of amorphous α-olefin polymer (amorphous propylene-butene-1 copolymer)]

In a 100 L stainless steel polymerization vessel equipped with a stirrer, hydrogen was used as the molecular weight modifier, and propylene and butene-1 were continuously copolymerized to obtain an amorphous propylene-butene-1 copolymer as an amorphous α-olefin polymer. Specifically, from the bottom of the polymerizer, hexane is continuously supplied as a polymerization solvent at a feed rate of 100 L / hour, propylene is 24.00 kg / hour, butene-1 is 1.81 kg / hour, and from the top of the polymerizer, The reaction mixture was drawn off continuously so that the reaction mixture in the polymerization reactor kept 100L. Furthermore, from the lower part of the polymerization machine, as a catalyst component, dimethylsilyl (tetramethylcyclopentadienyl) (3-t-butyl-5-methyl-2-phenoxy) titanium dichloride is 0.005 g / hour, and triphenyl is used. Methyl tetrakis (pentafluorophenyl) borate was continuously fed at 0.298 g / hour and triisobutylaluminum at a feed rate of 2.315 g / hour, respectively. The copolymerization reaction was carried out at 45 ° C. by circulating cooling water in a jacket attached to the outside of the polymerization reactor. A small amount of ethanol was added to the reaction mixture continuously drawn out from the top of the polymerization reactor, and the polymerization reaction was stopped, followed by a demonomer, water washing, and solvent removal step to obtain an amorphous propylene-butene-1 copolymer. Subsequently, the obtained copolymer was dried under reduced pressure at 80 degreeC for 24 hours. The content rate of the propylene monomeric unit in this amorphous propylene-butene-1 copolymer was 94.5 mass%, and the content rate of the butene-1 monomeric unit was 5.5 mass% (each monomer unit was a nuclear magnetic resonance apparatus JMN manufactured by Nippon Denshi KK. Calculated by LA300). Moreover, the melting peak in DSC (EXSTAR6000 made by Seiko Instruments Inc.) of the copolymer was not observed, and the intrinsic viscosity [η] was 2.3 dl / g and the molecular weight distribution (Mw / Mn) was 2.2 (molecular weight distribution). Analyzed by gel permeation chromatograph manufactured by Tosoh Corporation, HLC-8020).

Synthesis Example 2

[Synthesis of amorphous α-olefin polymer (amorphous propylene-ethylene-butene-1 copolymer)]

1 L of dry toluene was introduced as a polymerization solvent after depressurizing and nitrogen-substituting the 2 L separable flask reactor equipped with the stirrer, the thermometer, the dropping funnel, and the reflux condenser. Ethylene 2 x 10 ^-6 cm ³ / min, propylene 4 x 10 ^-6 cm ³ / min and butene-1 1 x 10 ^-6 cm ³ / min were continuously supplied at atmospheric pressure to set the solvent temperature to 30 deg. . After adding 0.75 mmol of triisobutylaluminum (hereinafter referred to as TIBA) to the polymerization tank, dimethylsilyl (tetramethylcyclopentadienyl) (3-t-butyl-5-methyl-2-phenoxy) titanium dichloride 0.0015 mmol Was added to the polymerization tank. After 15 seconds, 0.0075 mmol of triphenylmethyltetrakis (pentafluorophenyl) borate was added to the polymerization tank, and polymerization was performed for 10 minutes. As a result, an amorphous propylene-butene-1-ethylene copolymer was obtained. The content of the propylene monomer unit in this amorphous propylene-ethylene-butene-1 copolymer was 61.5 mass%, the content of the ethylene monomer unit was 21.0 mass%, and the content of the butene-1 monomer unit was 17.5 mass%. Moreover, the melting peak in DSC of this copolymer was not observed, In addition, intrinsic viscosity [(eta)] was 1.69 dl / g and molecular weight distribution (Mw / Mn) was 2.0.

(Example 1)

[Production of Pellet Made of Composition (1) Containing Amorphous α-olefin-Based Polymer]

To the amorphous propylene-butene-1 copolymer obtained in Synthesis Example 1, a crystalline propylene-butene-1 copolymer (density 0.900 g / cm ³ , MFR (value measured at 230 ° C., 21.18 N) 10.0 g / 10 Minute and the maximum melting peak of 126 DEG C in DSC] are blended so as to be amorphous propylene-butene-1 copolymer / crystalline propylene-butene-1 copolymer = 60/40 (mass ratio), and further, an aromatic phosphite system Antioxidant [Irgafos 168 by Chiba Specialty Chemicals Co., Ltd.] and hindered phenol-based antioxidant [Irganox 1010 by Chiba Specialty Chemicals Co., Ltd.] 2000 ppm each, melt kneaded at 230 ° C. with a twin screw extruder (PCM30, manufactured by IKEGAI, 30 mmφ screw), and then contained an amorphous α-olefin-based polymer by a granulator (CK2, manufactured by Nakata Nigikai Co., Ltd.). Pellets of the composition (1) were obtained.

(Production Example 2)

[Production of Pellet Made of Composition (2) Containing Amorphous α-olefin-Based Polymer]

A composition containing an amorphous α-olefin-based polymer in the same manner as in Production Example 1 except for blending it so as to be an amorphous propylene-butene-1 copolymer / crystalline propylene-butene-1 copolymer = 95/5 (mass ratio). The pellet of (2) was obtained.

(Production Example 3)

[Production of Pellet Made of Composition (3) Containing Amorphous α-olefin-Based Polymer]

In Preparation Example 1, except that the amorphous α-olefin polymer used was used as the amorphous propylene-ethylene-butene-1 copolymer obtained in Synthesis Example 2, and was prepared in the same manner as in Preparation Example 1, amorphous α-olefin. The pellet of the composition (3) containing a system polymer was obtained.

(Production Example 4)

[Production of Pellet Made of Composition (4) Containing Amorphous α-olefin-Based Polymer]

Amorphous propylene-ethylene-butene-1 copolymer / crystalline propylene-butene-1 copolymer was mixed so as to be 95/5 (mass ratio). Pellets of the composition (4) were obtained.

(Example 5)

[Production of Pellet Made of Composition (5) Containing Amorphous α-olefin-Based Polymer]

To the amorphous propylene-butene-1 copolymer obtained in Synthesis Example 1, linear low-density polyethylene (density 0.935 g / cm ³ , MFR (value measured at 190 ° C. and 21.18 N) 3.5 g / 10 min) was prepared. A pellet of the composition (5) containing an amorphous α-olefin-based polymer was prepared in the same manner as in Production Example 1 except that the propylene-butene-1 copolymer / linear low density polyethylene was added so as to have a mass ratio of 95/5 (mass ratio). Got it.

Example 1

As the resin for the surface layer, a propylene homopolymer (density: 0.900 g / cm ³ , MFR (value measured at 230 ° C., 21.18 N)): 8.0 g / 10 min; Hereinafter, referred to as "HOPP"] 80 parts by mass, ethylene-propylene block copolymer [density: 0.900 g / cm ³ , MFR (230 ° C., 21.18 N): 8 g / 10 min] using 20 parts by mass of a mixed resin, As the resin for the base layer, 30 parts by mass of the composition (1) containing the amorphous α-olefin-based polymer prepared above and HO-used as a resin for the adhesive layer and linear low density polyethylene [density: 0.902 g / cm ³ , MFR (value measured at 190 ° C. and 21.18 N): 3.0 g / 10 min; Hereafter referred to as "LLDPE (1)", a mixture of 70 parts by mass is supplied to the surface layer extruder (diameter 50 mm), the base layer extruder (diameter 50 mm), and the adhesive layer extruder (diameter 40 mm), respectively, for co-extrusion. By extrusion so that the thickness of the surface layer was 12 µm, the thickness of the substrate layer was 38 µm, and the thickness of the adhesive layer was 10 µm at an extrusion temperature of 250 ° C., and then cooled with a 40 ° C. water-cooled metal cooling roll. It wound up and obtained the surface protection film. In order to stabilize a physical property, the obtained film was aged for 48 hours in 35 degreeC aging room.

Example 2

Except having changed into 50 mass parts of compositions (1) and 50 mass parts of LLDPE (1) containing an amorphous (alpha) -olefin type polymer as an resin for adhesion layers using ethylene-propylene block copolymer as surface layer resin. In the same manner as in 1, a surface protective film was obtained.

Example 3

In the same configuration as in Example 2, each of these was fed to a surface layer extruder (diameter 50 mm), a substrate layer extruder (diameter 50 mm), and an adhesive layer extruder (diameter 40 mm), respectively, and coextruded from the T-die at an extrusion temperature of 250 ° C. Extruded so that the thickness of the surface layer is 40 micrometers, the thickness of a base material layer is 120 micrometers, and the thickness of an adhesion layer is 40 micrometers, and it cools with a 40 degreeC water-cooling metal cooling roll, and then it is 4 times at 140 degreeC by the proximity roll drawing method. It extended | stretched and heat-fixed at 145 degreeC, and obtained the surface protection film uniaxially stretched. In order to stabilize a physical property, the obtained film was aged for 48 hours in 35 degreeC aging room. In addition, the thickness of each layer of Example 3 of Table 1 is a thing after uniaxial stretching.

Example 4

As resin for adhesion layers, it carried out similarly to Example 2 except having changed into the mixture of 40 mass parts of compositions (2) and 60 mass parts of LLDPE (1) containing an amorphous (alpha) -olefin type polymer, and obtained the surface protection film.

Example 5

As resin for adhesion layers, 40 mass parts of compositions (4) containing an amorphous alpha-olefin type polymer, and linear low density polyethylene (density: 0.920 g / cm <^3> , MFR (measured at 190 degreeC, 21.18N): 4.0 g / 10 min; Hereafter, "LLDPE (2)" was obtained. The surface protection film was obtained like Example 2 except having used 60 mass parts of mixtures.

Example 6

As a resin for adhesion layers, the surface protection film was obtained like Example 2 except having used the mixture of 20 mass parts of compositions (5) and 80 mass parts of LLDPE (2) containing an amorphous alpha-olefin type polymer.

Example 7

10 parts by mass of composition (2) and 90 parts by mass of LLDPE (2) containing HOPP as the resin for the surface layer, the same HOPP as the resin for the base layer, and an amorphous α-olefin-based polymer as the resin for the adhesive layer. Using a mixed resin with the resin, it is supplied to the surface layer extruder (diameter 50 mm), the substrate layer extruder (diameter 50 mm) and the adhesive layer extruder (diameter 40 mm), respectively, and coextruded from the T-die at an extrusion temperature of 250 ° C. The surface protection film was obtained like Example 1 except having extruded so that the thickness of a surface layer might be 14 micrometers, the thickness of a base material layer was 42 micrometers, and the thickness of an adhesion layer was 14 micrometers.

Example 8

As the resin for the base layer, a metallocene catalyst-based ethylene-propylene random copolymer [density: 0.900 g / cm ³ , MFR (value measured at 230 ° C., 21.18 N): 7.0 g / 10 min, content of ethylene monomer unit: 3.5 mass%; Hereinafter, referred to as "metallocene catalyst COPP"], using a mixture of 50 parts by mass of the composition (3) and 50 parts by mass of LLDPE (2) containing an amorphous α-olefin-based polymer as the resin for the adhesive layer The substrate layer was supplied to an extruder (diameter 50 mm) and an adhesive layer extruder (diameter 40 mm), respectively, and the substrate layer had a thickness of 50 μm and a thickness of 10 μm from the T-die at an extrusion temperature of 250 ° C. by a coextrusion method. It extruded so that it might become, and after cooling with a 40 degreeC water-cooling metal cooling roll, it wound up on the roll and obtained the surface protection film. In order to stabilize a physical property, the obtained film was aged for 48 hours in 35 degreeC aging room.

Example 9

As the resin for the base layer, a metallocene catalyst-based COPP was used, and as a resin for the adhesion layer, except that a mixture of 6.0 parts by mass of the composition (2) and 94 parts by mass of the LLDPE (2) containing an amorphous α-olefin polymer was used. In the same manner as in Example 2, a surface protective film was obtained.

Example 10

6.0 mass parts of compositions (2), 84 mass parts of LLDPE (2), and ethylene-butene-1 which use a metallocene catalyst type COPP as resin for a base material layer, and contain an amorphous alpha-olefin type polymer as resin for adhesion layers Copolymer (density: 0.895 g / cm ³ , MFR (value measured at 190 ° C. and 21.18 N): 3.0 g / 10 min; Hereinafter, referred to as "EBR"] A surface protective film was obtained in the same manner as in Example 2 except that a mixture of 10 parts by mass was used.

Example 11

A mixture of 30 parts by mass of composition (2), 50 parts by mass of LLDPE (2), and 20 parts by mass of EBR containing a metallocene catalyst COPP as the resin for the base layer, and containing an amorphous α-olefin polymer as the resin for the adhesive layer. A surface protective film was obtained in the same manner as in Example 2 except for using.

Example 12

A mixture of 20 parts by mass of composition (2) and 40 parts by mass of LLDPE (2) and 40 parts by mass of EBR containing a metallocene catalyst COPP as the resin for the base layer and containing an amorphous α-olefin polymer as the resin for the adhesion layer. A surface protective film was obtained in the same manner as in Example 2 except for using.

Example 13

As resin for base materials, high density polyethylene [density: 0.960 g / cm <^3> , MFR (value measured by 190 degreeC, 21.18N): 13 g / 10min; Hereinafter referred to as "HDPE"] 50 parts by mass and low density polyethylene (density: 0.902 g / cm ³ , MFR (value measured at 190 ° C. and 21.18 N)): 4 g / 10 min; 30 parts by mass of the composition (1) and 70 parts by mass of LLDPE (1) containing the amorphous α-olefin-based polymer prepared above as a resin for an adhesive layer, using 50 parts by mass of a mixed resin) (hereinafter referred to as "LDPE"). Using a mixed resin, the substrate layer was supplied to an extruder (diameter 50 mm) and an adhesive layer extruder (diameter 40 mm), respectively, and the substrate layer had a thickness of 56 μm and a pressure-sensitive adhesive layer from the T-die at an extrusion temperature of 250 ° C. by a coextrusion method. It extruded so that the thickness might be set to 14 micrometers, and after cooling with a 40 degreeC water-cooling metal cooling roll, it wound up on the roll and obtained the surface protection film. In order to stabilize a physical property, the obtained film was aged for 48 hours in 35 degreeC aging room.

Example 14

As a resin for adhesion layers, the surface protection film was obtained like Example 13 except having used 50 mass parts of compositions (1) and 50 mass parts of LLDPE (1) mixed resin containing an amorphous (alpha) -olefin type polymer.

Example 15

As a resin for adhesion layers, the surface protection film was obtained like Example 13 except having used the mixture resin of 40 mass parts of compositions (2) containing an amorphous alpha-olefin type polymer, and 60 mass parts of LLDPE (1).

Example 16

As a resin for adhesion layers, the surface protection film was obtained like Example 13 except having used the mixed resin of 40 mass parts of compositions (4) and 60 mass parts of LLDPE (1) containing an amorphous alpha-olefin type polymer.

(Example 17)

As a resin for adhesion layers, it carried out similarly to Example 13 except having used 40 mass parts of compositions (2) containing 40% of LLDPE (1), and 20 mass parts of EBR containing an amorphous (alpha) -olefin type polymer, and a surface protection film. Got.

(Example 18)

As a resin for adhesive layers, the surface protection film was obtained like Example 13 except having used the mixed resin of 15 mass parts of compositions (2) and 85 mass parts of LLDPE (2) containing an amorphous alpha-olefin type polymer.

Example 19

As resin for surface layers, 95 mass parts of LDPE and 5 mass parts of ethylene-propylene block copolymers are used, and as resin for a base material layer, 50 mass parts of HDPE and 50 mass parts of LDPE are used, and as resin for adhesion layers, A surface layer extruder (diameter 50 mm), a substrate layer extruder (a diameter 50 mm), and an adhesive layer extruder, using 10 parts by mass of a composition (2) containing an amorphous α-olefin-based polymer and 90 parts by mass of a mixed resin of LLDPE (2). (40 mm diameter), and extruded by a coextrusion method at a extrusion temperature of 250 ° C. so that the surface layer had a thickness of 14 μm, the base layer had a thickness of 42 μm, and the adhesive layer had a thickness of 14 μm from the T-die. In the same manner as in Example 13, a surface protective film was obtained.

Example 20

As a resin for surface layers, the surface protection film was obtained like Example 19 except having used the mixture resin of 85 mass parts of HOPP and 15 mass parts of ethylene-propylene block copolymers.

(Example 21)

As the resin for the surface layer, 95 mass parts of LLDPE (1) and 5 mass parts of mixed resin of ethylene-propylene block copolymer were used, and surface protection was performed like Example 19 except having used LLDPE (1) as resin for a base material layer. A film was obtained.

(Example 22)

As a resin for surface layers, 95 mass parts of LLDPE (2) and 5 mass parts of mixed resins of ethylene-propylene block copolymer were used, and surface protection film was carried out similarly to Example 19 except having used LLDPE (2) as resin for base materials. Got.

(Example 23)

As resin for surface layers, linear low-density polyethylene [density: 0.940 g / cm <^3> , MFR (value measured by 190 degreeC, 21.18N): 4.0 g / 10min; Hereinafter, referred to as "LLDPE (3)" surface protection in the same manner as in Example 19 except that 95 parts by mass of a mixed resin and 5 parts by mass of an ethylene-propylene block copolymer were used, and LLDPE (3) was used as the base layer resin. A film was obtained.

Example 24

A surface protective film was obtained in the same manner as in Example 18 except that LDPE was used as the resin for the base layer.

(Example 25)

LDPE was used as the base layer resin, and 10 parts by mass of a composition (2) containing an amorphous α-olefin-based polymer and 90 parts by mass of a mixed resin of LLDPE (2) were used as the adhesive layer resin. In the same manner, a surface protective film was obtained.

Example 26

As a resin for adhesive layers, the surface protection film was obtained like Example 19 except having used the mixture of 20 mass parts of compositions (5) and 80 mass parts of LLDPE (2) containing an amorphous alpha-olefin type polymer.

(Comparative Example 1)

As a resin for adhesion layers, it carried out similarly to Example 2 except having used the mixture of 3.16 mass parts of compositions (2) containing an amorphous alpha-olefin type polymer, and 96.84 mass parts of LLDPE (2), and used the comparative surface protection film Got it.

(Comparative Example 2)

As a resin for adhesion layers, it carried out similarly to Example 2 except having used the mixture of 30 mass parts of compositions (1) containing an amorphous alpha-olefin type polymer, and 70 mass parts of LLDPE (3), and used the comparative surface protection film. Got it.

(Comparative Example 3)

As resin for adhesion layers, 52 mass parts of compositions (2) containing an amorphous alpha-olefin type polymer, 8 mass parts of crystalline propylene-butene-1 copolymers like those used by the manufacture example 1, and styrene ethylene propylene styrene A surface protective film for comparison was obtained in the same manner as in Example 2, except that a mixture of 40 parts by mass of a block copolymer ("Septon 2063" manufactured by Kuraray Co., Ltd .; hereafter referred to as "SEPS") was used.

(Comparative Example 4)

As a resin for adhesion layers, the surface protection film for comparison was obtained like Example 2 except having used the mixture of 50 mass parts of compositions (1) and 50 mass parts of HOPP containing an amorphous alpha-olefin type polymer.

(Comparative Example 5)

As a resin for adhesion layers, it carried out similarly to Example 2 except having used the mixture of 50 mass parts of compositions (1) containing an amorphous (alpha) -olefin type polymer, 30 mass parts of LLDPE (2), and 20 mass parts of EBR. The surface protection film of was obtained.

(Comparative Example 6)

As a resin for adhesion layers, it carried out similarly to Example 2 except having used the mixture of 30 mass parts of compositions (2) containing an amorphous alpha-olefin type polymer, 20 mass parts of LLDPE (2), and 50 mass parts of EBR. The surface protection film of was obtained.

(Comparative Example 7)

As a resin for adhesion layers, it carried out similarly to Example 13 except having used mixed resin of 3.16 mass parts of compositions (2) containing amorphous alpha-olefin type polymer, and 96.84 mass parts of LLDPE (2), and used the comparative surface protection film. Got it.

(Comparative Example 8)

As a resin for adhesion layers, it carried out similarly to Example 13 except having used the mixed resin of 30 mass parts of compositions (1) containing an amorphous alpha-olefin type polymer, and 70 mass parts of LLDPE (3), and used the comparative surface protection film. Got it.

(Comparative Example 9)

As the resin for the adhesive layer, 52 parts by mass of the composition (2) containing the amorphous α-olefin-based polymer, 8 parts by mass of the crystalline propylene-butene-1 copolymer as used in Production Example 1, and a mixed resin of SEPS 40 parts by mass were used. A surface protective film for comparison was obtained in the same manner as in Example 13 except for using.

(Comparative Example 10)

As a resin for pressure-sensitive adhesive layers, a surface protective film for comparison was obtained in the same manner as in Example 13, except that 50 parts by mass of the composition (1) containing the amorphous α-olefin-based polymer and 50 parts by mass of a mixed resin of HOPP were used.

(Comparative Example 11)

As resin for adhesion layers, it carried out similarly to Example 13 except having used 50 mass parts of compositions (1) containing an amorphous alpha-olefin type polymer, 30 mass parts of LLDPE (2), and 20 mass parts of EBR. The surface protection film of was obtained.

The following measurements and evaluations were performed using the surface protection films obtained in the said Examples 1-26 and Comparative Examples 1-11.

(1) Measurement of adhesion

In the constant temperature room of 23 degreeC and 50% RH, the surface protection film obtained above was made into the acrylic plate of 2 mm in thickness (mirror surface finish, "Acrylic light" by Mitsubishi Rayon Corporation) according to the adhesive force evaluation method of JISZ0237: 2000. Stuck on. After leaving the acrylic plate on which the film was stuck for 24 hours in a 23 ° C. constant temperature room, a tensile tester (manufactured by A & D Co., Ltd.) was used to peel off in a 180 ° direction at a speed of 300 mm / min to measure initial adhesive force. Moreover, after leaving the acrylic plate on which the film was stuck for 1 day in a 50 degreeC dryer, adhesive force was measured similarly.

(2) Evaluation of adhesiveness

In order to measure the said adhesive force, the adhesion | attachment state to the acrylic plate of the surface protection film at the time of sticking a surface protection film to an acryl plate was visually confirmed, and the adhesiveness was evaluated by the following reference | standard.

○: Maintaining uniform adhesion to the acrylic plate surface

X: Unable to maintain uniform adhesion and moxibustion occurred in part

(3) Evaluation of pool male voice

In the constant temperature room of 23 degreeC and 50% RH, the surface protection film was made into the front surface of the acrylic plate (mirror finish, Mitsubishi Rayon Co., Ltd. make "acryllite") of 15 cm x 5 cm by the method based on JISZ0237: 2000. Stuck on. The acrylic plate with a film adhered was left to stand in a 60 degreeC dryer for 3 days, and then cooled in a 23 degreeC constant temperature room for 1 hour. The film was peeled off by hand at a high speed in the 180 ° direction from the cooled test piece, and the contamination state on the surface of the acrylic plate was visually confirmed, and the pooling performance was evaluated based on the following criteria.

(Circle): There is no contamination, such as a blur, white stripe, a foreign material, on the surface of an acryl board

X: The surface of an acryl board has any contamination, such as a blur, a white stripe, and a foreign material

(4) Measurement of the wetting tension on the acrylic plate surface

The wet tension of the acrylic plate surface was measured by the method based on JISK6768: 1999 using the test piece in which the film peeled in the evaluation of said (3).

(5) Print aptitude evaluation after protective film peeling

The width of the drop in wet tension from the blank value of the wet tension obtained in the measurement of (4) (wet tension measured by the same method after washing the surface of the acrylic plate before film bonding with alcohol and drying). It evaluated as substitution evaluation of the printability after protective film peeling. In addition, evaluation criteria are as follows.

(Circle): The fall width of wet tension is 2 mN / m or less with respect to a blank.

X: The fall width of wet tension exceeded 2 mN / m with respect to a blank

(6) Evaluation of blocking resistance

The obtained surface protection film was cut out to the magnitude | size (A297 mm x 210 mm) of A4. At this time, it cut out so that the extrusion direction (MD direction) and A4 longitudinal direction at the time of film-film formation might correspond. After stacking 10 pieces of cut out films, the upper and lower parts are sandwiched by a plate of A4 size and a vinyl chloride having a thickness of 3 mm, and a weight of 5 kg is placed and stored in a dryer at 40 ° C. for 14 days, followed by 23 ° C. and 50% RH. It was stored for 1 hour in the greenhouse. Subsequently, the film was cut out to 25 mm width in the MD direction, and it peeled in the 180 degree direction at the speed | rate of 300 mm / min using the tensile tester (made by A & D), and measured the blocking force. From the obtained blocking force, the blocking resistance was evaluated by the following criteria.

○: blocking force is less than 0.8N / 25mm

×: blocking force is 0.8N / 25mm or more

(7) Evaluation of cutting property

In the constant temperature room of 23 degreeC and 50% RH, the surface protection film obtained above was made into the acrylic plate of 2 mm in thickness (mirror surface finish, "Acrylic light" by Mitsubishi Rayon Corporation) according to the adhesive force evaluation method of JISZ0237: 2000. Stuck on both sides of the. The cross section of the film at the time of cut | disconnecting the acrylic plate with a film with the high speed cutter was visually observed, and the cutting property was evaluated by the following references | standards.

(Circle): Appearance defects, such as a stickiness, a fluff, and a crack, are not seen in the cut edge of a film.

(Triangle | delta): Appearance defects, such as a stickiness, a fluff, and a crack, are seen in the cut edge of a film a little.

×: Appearance defects such as slippage, lint, and cracking are observed on the cut end surface of the film.

The laminated constitution of the surface protection film produced above and the evaluation result obtained using these surface protection films are shown to Tables 1-6. In addition, in the Example and comparative example which did not provide a surface layer, the column is blank. About the composition containing the amorphous alpha-olefin type polymer used for the adhesion layer, it divided and described for each component.

TABLE 1

[Table 2]

[Table 3]

Table 4

[Table 5]

Table 6

From the result of Examples 1-26, the surface protection film of this invention is about 0.1-2.2N / 25mm in adhesive force with respect to an acryl plate, and the width | variety of the microadhesive-medium adhesion level optimal as a surface protection film is optimal. It was found to have a wide adhesive force. Moreover, it turned out that there is no generation | occurrence | production of peeling, peeling, etc. after sticking to an acryl plate, and it has favorable adhesiveness practically as a surface protection film. In particular, when peeling the film from the adhered acrylic plate, contamination such as blur, streaks, and foreign matters that can be seen with the naked eye is not recognized, and the decrease in the wet tension on the surface of the acrylic plate after peeling off the surface protection film is extremely small. After peeling off a surface protection film, it turned out that it can use suitably for the use which performs secondary processing, such as printing. Moreover, when using an ethylene polymer for a base material layer, when cut-processing a to-be-adhered body in the state in which the surface protection film was stuck to the to-be-adhered body, a surface protection film is cut | disconnected neatly and an appearance defect, such as slippage and fluff, does not arise. It turned out that the surface protection film which has the outstanding cutting property is obtained.

Comparative example 1 is an example of the surface protection film which made the compounding quantity of linear low-density polyethylene into about 97 mass% exceeding 95 mass% of the prescribed upper limit. In the surface protection film of this comparative example 1, the adhesive force was only about 0.05 N / 25 mm as an initial value, and it turned out that generation | occurrence | production of peeling, peeling, etc. are seen by light impact, and adhesive force is inadequate.

Comparative Example 2 is an example of the linear density of the low density polyethylene, a surface protective film to 0.938g / cm ³ of a specified upper limit to 0.940g / cm ³ in excess. In the surface protection film of this comparative example 2, adhesive force is only about 0.03N / 25mm as an initial value, and the occurrence of steaming or peeling is seen immediately after sticking of a film, and when the density of the linear low density polyethylene to mix | blends is too high, adhesive force This was found to be insufficient.

Comparative Example 3 is an example of a surface protective film using no styrene-ethylene-propylene-styrene block copolymer (SEPS) instead of using linear low density polyethylene in the adhesive layer. In the surface protection film of this comparative example 3, the generation | occurrence | production of the loosening was seen, It turned out that the wet tension of the surface of the acryl plate after peeling off a surface protection film is also large, blocking force is large, and blocking resistance is also inferior.

Comparative Example 4 is an example of a surface protective film using no linear low-density polyethylene in the pressure-sensitive adhesive layer, but using a propylene homopolymer instead. In the surface protection film of this comparative example 4, the generation | occurrence | production of a loosening was seen and it turned out that the fall of the wet tension of the acrylic plate surface after peeling a surface protection film is also large.

Comparative example 5 is an example of the surface protection film which made compounding quantity of linear low-density polyethylene into 37.5 mass% less than 40 mass% of the prescribed minimum. In the surface protection film of this comparative example 5, it turned out that there exists a problem which annealing generate | occur | produces.

Comparative example 6 is an example of the surface protection film which made the compounding quantity of an ethylene-alpha-olefin copolymer (EBR) into about 50.8 mass% exceeding 40 mass% of a prescribed upper limit. In the surface protection film of this comparative example 6, the blocking force was large and it turned out that blocking resistance is inferior.

Comparative Example 7 is an example of a surface protective film wherein the blending ratio of the amorphous propylene-butene-1 copolymer of the pressure-sensitive adhesive layer with the linear low density polyethylene is less than 5 mass% of the lower limit. In the surface protection film of this comparative example 7, the adhesive force was only about 0.05 N / 25 mm as an initial value, and it turned out that generation | occurrence | production of peeling, peeling, etc. are seen by light impact, and adhesive force is inadequate.

Comparative Example 8 is an example of the straight-chain low-density polyethylene of a density, a surface protective film to 0.938g / cm ³ of a specified upper limit to 0.940g / cm ³ greater than that used for the adhesive layer. In the surface protection film of this comparative example 8, the adhesive force is only about 0.03 N / 25mm as an initial value, the occurrence of steaming, peeling, etc. is seen immediately after sticking of a film, and when the density of the linear low density polyethylene mix | blended is too high, This was found to be insufficient.

Comparative Example 9 is an example of a surface protective film using no styrene-ethylene-propylene-styrene block copolymer (SEPS) instead of using linear low-density polyethylene for the adhesive layer. In the surface protection film of this comparative example 9, generation | occurrence | production of a loosening was seen, It turned out that the wet tension of the surface of the acryl plate after peeling off a surface protection film is also large, blocking force is large, and blocking resistance is also inferior.

Comparative Example 10 is an example of a surface protective film using no linear low-density polyethylene in the pressure-sensitive adhesive layer, but using a propylene homopolymer instead. In the surface protection film of this comparative example 10, the generation | occurrence | production of a loosening was seen, and it turned out that the fall of the wet tension of the acrylic plate surface after peeling a surface protection film is also large.

Comparative Example 11 is an example of a surface protective film wherein the blending ratio of the amorphous propylene-butene-1 copolymer of the pressure-sensitive adhesive layer with the linear low-density polyethylene is 50% by mass exceeding 40% by mass of the upper limit. In the surface protection film of this comparative example 11, it turned out that there exists a problem which annealing generate | occur | produces.

The surface protection film of this invention has the wide adhesive force of the optimal unadhesive-medium adhesion level, and there is no generation | occurrence | production of peeling, peeling, etc. after sticking to an acryl plate. In particular, when peeling the film from the adhered acrylic plate, contamination such as blur, streaks, and foreign matters that can be seen with the naked eye is not recognized, and the decrease in the wet tension on the surface of the acrylic plate after peeling off the surface protection film is extremely small. After peeling a surface protection film, it is suitable for the use which performs secondary processing, such as printing.

Claims (6)

As a surface protection film which laminated | stacked the adhesion layer (A) and the base material layer (B), the adhesion layer (A),
Amorphous α- olefin polymer (A1) is 5 to 50% by weight and a density of 0.880~0.938g / cm ³ linear low-density polyethylene (A2) a resin blend of 50-95% by weight, or,
5-50 mass% of amorphous (alpha) -olefin type polymer (A1), 40-90 mass% of linear low-density polyethylene (A2) whose density is 0.880-0.938 g / cm <^3> , and a crystalline ethylene-alpha-olefin copolymer (A3) 5-50 mass% mixed resin
The surface protection film which has a main component. The method of claim 1,
The said base material layer (B) is a surface protection film whose main component is an ethylene polymer (B1) or a crystalline propylene polymer (B2). The method according to claim 1 or 2,
The amorphous α-olefin-based polymer (A1) is an amorphous propylene-butene-1 copolymer or an amorphous propylene-ethylene-butene-1 copolymer. 4. The method according to any one of claims 1 to 3,
The said protective ethylene-alpha-olefin copolymer (A3) is an ethylene-butene-1 copolymer. The method according to any one of claims 1 to 4,
The surface protection film which provided the surface layer (C) which has an olefinic polymer as a main component in the surface opposite to the surface which laminated | stacked the adhesion layer (A) in the said base material layer (B). The method according to any one of claims 1 to 5,
Surface protection film extended | stretched in at least 1 axial direction.