KR101162583B1 - Surface protection film - Google Patents

Abstract

The present invention adheres to the surface of the various resin plates, glass plates, metal plates and the like used in building materials, electrical and electronic fields, etc. to protect the surface from scratches, contamination, etc. during storage, transportation and post-processing. It is about surface protection film to protect. Specifically, as a resin used for the adhesion layer of a surface protection film, the main component is a resin which mixed the block copolymer which has a crystalline olefin block, and the linear low-density polyethylene of density 0.880-0.938 g / cm <^3> in a specific ratio. By using it as an example, the surface protection film which has very little contamination to the to-be-adhered body surface and is excellent also in secondary processing aptitude is provided.

Description

Surface protection film {SURFACE PROTECTION FILM}

The present invention is a surface protection film used for the purpose of protecting the surface of various resin plates, glass plates, metal plates and the like, in particular, the contamination of the adherend on the surface of the adherend after film peeling is extremely small, and the secondary of the adherend It is related with the surface protection film which can maintain workability.

A surface protection film is used for the purpose of sticking to the surfaces of various resin plates, glass plates, metal plates, etc. used in building materials, an electrical / electronic field, etc., and protecting these to-be-adhered surfaces from abrasion, a contamination, etc. For the purpose of satisfying the various required performances for surface protective films, a number of inventions have been reported so far. One of the required performances for the surface protection film is minimization of contamination by sticking to the adherend surface after film peeling. In the case where secondary processing such as printing is performed on the adherend after peeling off the film, even if the microscopic contamination of the degree which cannot be visually confirmed affects the workability, a very high level of reduction of the pooling is required. As other required performance, after winding up a film in roll shape, the contact surface of a film does not come off easily when peeled and used, there is no so-called blocking, the state in which the film adhered to a to-be-adhered body In the case where the heat treatment or the like is performed, there is no lifting or peeling from the adherend, an increase in the adhesive strength with the passage of time after the film sticking, and there is no so-called adhesion acceleration. In addition, after the surface protection film is stored and transported in a state where the surface protective film is stuck to various adherends at the actual site of use, the protective film is peeled off from the adherend once, the surface state of the adherend and the like are examined, and then the surface is again applied. A protective film may be stuck and provided to post-processing etc. If the adhesive surfaces adhere to each other at such a site of use, when the adhesion between the adhesive surfaces is strong, when attempting to peel off the adhesive portions, whitening and roughness may occur on the adhesive surfaces, and the adhesive portions are easily peeled off. Therefore, new problems, such as poor handling property, which can adhere the surface protective film to the adherend again, have arisen. In order to combine these, various technical devises are necessary, such as not only adjusting the adhesive performance of an adhesion layer suitably, but selecting a suitable combination of resin in consideration of the affinity of an adhesion layer and a base material layer.

As a prior art of the surface protection film, the block air which has the base material layer which consists of a thermoplastic resin, an amorphous olefin copolymer, a crystalline olefin type polymer, and a crystalline olefin block as an example which aimed at suppressing the adhesion promotion of a surface protection film is shown. Coextruded laminated film having a pressure-sensitive adhesive layer made of a copolymer (see Patent Document 1, for example), a crystalline propylene polymer as an example to improve the heat workability in the state that the surface protective film is stuck to the adherend The coextrusion laminated | multilayer film (for example, refer patent document 2) which has a base material layer which is a main component, and the adhesion layer which consists of an amorphous alpha-olefin type copolymer and a crystalline propylene polymer, a surface protection film adheres to a to-be-adhered body Propylene homopolymerization as an example which aimed at suppressing the blocking at the time of unwinding and using after heat-processing property in the rolled state and winding up a film in roll shape A surface layer composed mainly of a polypropylene resin composed of a sieve and a propylene-ethylene copolymer elastomer, a base layer composed mainly of a crystalline propylene polymer, an amorphous α-olefin copolymer and a crystalline propylene polymer Coextrusion laminated | multilayer film (for example, refer patent document 3) which has an adhesion layer, etc. are mentioned.

In these techniques, however, the effect is reliably suppressed in the suppression of the adhesion enhancement of the film, the heat workability in the state where the film is stuck to the adherend, the suppression of the blocking after the film winding, and the like. Minimization of contamination by loosening on the surface of the adherend was insufficient, and there was a problem in secondary workability of the adherend after film peeling. Moreover, also about the peelability when the surface protection film adheres, it is not fully solved.

[Prior Art Literature]

[Patent Documents]

Patent Document 1: Japanese Patent Application Laid-Open No. 2006-257247

Patent Document 2: Japanese Patent Application Laid-Open No. 2007-130872

Patent Document 3: Japanese Patent Application Laid-Open No. 2008-68564

SUMMARY OF THE INVENTION [

[Problems that the invention tries to solve]

Therefore, the subject which this invention is going to solve is providing the surface protection film which can maintain the secondary workability of a to-be-adhered body very well, and contamination, such as sticking to the to-be-adhered body surface after surface protection film peeling, is favorable, Moreover, also when the adhesive faces of a surface protection film adhere, it is providing the surface protection film excellent in peelability and excellent handling property.

[Means for solving the problem]

MEANS TO SOLVE THE PROBLEM As a result of earnestly researching in order to solve the said subject, the surface protection film has the block copolymer which has a crystalline olefin block, and the adhesive layer whose main component is a linear low density polyethylene with a density of 0.880-0.938 g / cm <^3> . In the case of having a film, contamination on the surface of the adherend after peeling of the film was extremely small, and it was found that the surface protection film was able to maintain the secondary workability of the adherend satisfactorily. Thus, 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 said adhesion layer (A) has a block copolymer (A1) which has a crystalline olefin block, and density is 0.880. Block copolymer (A1) which contains 50 mass% or more of linear low density polyethylene (A2) of -0.938 g / cm <^3> with respect to the total mass of the component which comprises the said adhesion layer (A), and has a crystalline olefin block. And 5 to 80% by mass of the total mass with the linear low density polyethylene (A2) having a density of 0.880 to 0.938 g / cm ³ is a block copolymer (A1) having a crystalline olefin block. To provide.

[Effects of the Invention]

According to the present invention, as a surface protection film used for the purpose of adhering to the surface of various resin plates, glass plates, metal plates, etc. used in building materials, electrical and electronic fields, etc., and protecting these adherend surfaces from scratches, contamination, etc., a film When there is no blocking at the time of unwinding and using after winding up in roll shape, even if heat processing etc. are performed in the state in which the film adhered to the to-be-adhered body, it has high heat resistance, such as no lifting or peeling from the to-be-adhered body, and after film adhesion Since there is no adhesion increase and there is very little contamination by the sticking to the to-be-adhered body surface after film peeling, the high value of the surface protection film which can maintain the secondary workability of a to-be-adhered body favorable can be obtained. Moreover, when using a propylene polymer together in an adhesion layer, even when the adhesion surfaces of a surface protection film adhere, it is excellent in peelability, and surface roughness, whitening, etc. do not arise in the adhesion surface after peeling again, and surface protection is carried out again. It can be used as a film.

[Mode for Carrying Out the Invention]

The adhesion layer (A) which comprises the surface protection film of this invention has a block copolymer (A1) which has a crystalline olefin block, and a linear low density polyethylene (A2) whose density is 0.880-0.938 g / cm <^3> as a main component. Specifically, the total mass of the block copolymer (A1) having the crystalline olefin block and the linear low density polyethylene (A2) is 50% by mass based on the total amount of the components constituting the adhesive layer (A). It is characterized by containing as above. In particular, in the case of focusing on reduction of looseness to the adherend and low pollution, it is preferable that the total mass of the block copolymer (A1) and the linear low density polyethylene (A2) is contained at 80% by mass or more.

Block copolymer (A1) which has the said crystalline olefin block used here is a copolymer which has the block (I) which consists of crystalline polyolefin, and the other block (II) which does not have crystallinity, Preferably, It has a block which consists of conjugated diene type polymer as said other block (II). In addition, as a structure of the said copolymer, since the performance balance of the adhesiveness of a surface protection film obtained when it is used as resin for adhesion layer (A) in combination with linear low density polyethylene (A2) mentioned later, and outstanding remarkability is especially excellent. _Wherein at least one end of the polymer chain, represented by (I-II) _n1 or (I-II) _n2- (I) (n1, n2 is an integer of 1 or more), consists of crystalline olefin block (I) Is preferably.

As a block copolymer (A1) which has such a crystalline olefin block, what is provided by Unexamined-Japanese-Patent No. 3-128957 and 8-231786 is mentioned, for example. Specifically, polybutadiene polymer blocks having a low 1,2-vinyl bond content (for example, 25% or less) and polymers mainly containing a conjugated diene compound have a high 1,2- and 3,4-bond content ( For example, the copolymer which consists of 50% or more) polymer blocks is synthesize | combined, and this polybutadiene part is made into the structure similar to polyethylene by making hydrogenation, and the thing made into a crystalline polymer block is mentioned.

As said conjugated diene compound, for example, 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, 4 And 5-diethyl-1,3-octadiene, 3-butyl-1,3-octadiene, chloroprene and the like. From the viewpoint of industrial availability, it is preferable to use 1,3-butadiene and isoprene. desirable. As a commercial item which can be used suitably as a block copolymer which has such a crystalline olefin block, For example, the block copolymer which has the structure of a crystalline olefin ethylene butylene copolymer crystalline olefin (Hereinafter, it is referred to as CEBC. "Dynaron 6200P" by JSR, Inc. is mentioned.

In addition to the block copolymer (A1) which has a crystalline olefin block, the adhesion layer (A) which comprises the surface protection film of this invention contains a linear low density polyethylene (A2) whose density is 0.880-0.938 g / cm <^3> as a main component. Should be one of. When the density of linear low-density polyethylene (A2) uses 0.898-0.925 g / cm <^3> , since the balance of the adhesiveness suppression effect and adhesiveness of the surface protection film finally obtained becomes favorable, it is more preferable. Moreover, the value measured at 190 degreeC and 21.18 N based on the melt flow rate [JIS K7210: 1999. Hereinafter, "the film is represented by MFR (190 degreeC)" is preferable because it is a range of 0.5-30.0 g / 10min, since film-forming property of a film improves. Moreover, it is more preferable that MFR is the range of 2.0-15.0g / 10min.

The adhesive layer (A) which comprises the surface protection film of this invention is a block copolymer (A1) which has a crystalline olefin block as a main component, and linear low density polyethylene (A2) whose density is 0.880-0.938 g / cm <^3> . ) Together, the contamination on the surface of the adherend after film peeling can be minimized, and the secondary workability of the surface of the adherend can be maintained.

As a use ratio of the block copolymer (A1) which has a crystalline olefin block in the said adhesion layer (A), and the linear low density polyethylene (A2) whose density is 0.880-0.938 g / cm <^3> , (A1) and (A2) It is essential that 5 to 80% by mass of the total mass of the compound is a block copolymer (A1) having a crystalline olefin block. When the use ratio is within this range, the balance between low fouling on the surface of the adherend and adhesive force is maintained. That is, when the use ratio of the said block copolymer (A1) is less than 5 mass%, adhesive force is insufficient, peeling off and sticking after adhesion easily occur, and the use ratio of the said block copolymer (A1) exceeds 80 mass%. As a result, when adhesive force becomes strong, blocking at the time of storing in roll shape may occur easily, or low contamination property to a to-be-adhered body surface may run short.

As resin used for the adhesion layer (B) of the surface protection film of this invention, what is necessary is just to contain the above-mentioned block copolymer (A1) and linear low density polyethylene (A2) in total at 50 mass% or more, and other resins In particular, other olefin polymers may be further contained. At this time, it is preferable to use together a propylene polymer (A3) from the point of peelability in the case where adhesiveness of adhesive surfaces arises, and the reusability after peeling.

Examples of the propylene polymer (A3) include a propylene homopolymer, a propylene-ethylene copolymer, a propylene-butene-1 copolymer, a propylene-ethylene-butene-1 copolymer, a metallocene catalyst-based polypropylene, and the like. Can be. These may be used independently or may use 2 or more types together. Moreover, as for these propylene polymers (A3), it is preferable that 230 degreeC MFR is 0.5-30.0 g / 10min, and melting | fusing point is 120-165 degreeC, More preferably, MFR of 230 degreeC is 2.0-15.0 g / 10 minutes, melting | fusing point is thing of 125-162 degreeC. If the MFR and melting point of 230 deg. C are within this range, there is little shrinkage of the film 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 lifting or peeling, and no warpage is caused to the adherend. The film-forming property of a film also improves.

Moreover, among the propylene polymer (A3) used for the said adhesion layer (A), a metallocene catalyst type polypropylene is preferable. 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, and a metallocene compound on which a metallocene compound is supported on a particulate carrier. And supported catalysts. 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 in molecular weight distribution and composition distribution and has low content of low molecular weight components, the metallocene catalyst polypropylene is used in the propylene polymer (A3) to provide low molecular weight components. Contamination of the adherend surface due to bleed can be prevented. Further, the metallocene catalyst-based polypropylene may be a propylene homopolymer or a copolymer of propylene with another α-olefin, and examples of the copolymer of propylene with other α-olefins include propylene-ethylene copolymers. have.

In the adhesion layer (A), the block copolymer (A1) having a crystalline olefin block, a linear low density polyethylene (A2) having a density of 0.880 to 0.938 g / cm ³ , and a propylene polymer (A3) are used in combination. In that case, it is preferable that the total mass is 80 mass% or more with respect to the total mass of the component which comprises an adhesion layer (A) from the point which is excellent in the performance balance of the surface protection film obtained.

Moreover, the use ratio (A1) of each component in 100 mass parts of said block copolymer (A1), the said linear low density polyethylene (A2), and the said propylene polymer (A3) in total: (A2): (A3) It is more preferable that it is in the range of 10-50: 10-70: 10-50, although adhesiveness is appropriate, since it can peel easily at the time of the adhesion of adhesive surfaces, and can reuse after peeling. That is, adhesive force is enough that the use ratio of (A1) is 10 mass% or more, and the loosening after peeling can be prevented if it is 50 mass% or less. When the use ratio of (A2) is 10% by mass or more, whitening and surface roughness of the adhesive surface at the time of adhesion can be prevented, and an appropriate adhesive force is easily obtained when it is 70 mass% or less. Moreover, when the use ratio of (A3) is 10 mass% or more, peeling at the time of adhesion is easy, and when it is 50 mass% or less, it is easy to prevent the whitening and surface roughness after peeling.

In the adhesion layer (A) of this invention, even if it uses together the said component (A1) and a component (A3), in order to have practical adhesive force as a low pollution resistance, blocking resistance, and a surface protection film to a to-be-adhered body, the It is known that a practical surface protection film is obtained by managing a mixing ratio. However, since only the component (A1) and the component (A3) have a difference in the intrinsic properties (flexibility) of the resin, it is difficult to control the adhesiveness, resulting in the fact that the degree of freedom in industrial production is narrow and not practical. It was found that the combination of component (A1) and component (A2) and the combination of component (A3) are preferred. As a result, the adhesive layer (A) can also be made into the mixture which used together other resin, various additives, etc. in the range which does not impair the effect of this invention. As other resins, in the range which does not impair the effect of this invention, it is possible to use resin used conventionally when obtaining a film by a co-extrusion lamination method, and can use various olefin type polymer especially.

Resin which comprises the base material layer (B) used in addition to the adhesion layer (A) which comprises the surface protection film of this invention is not specifically limited, if coextrusion with the adhesion layer (A) is possible as a thermoplastic resin, 65 mass% or more is contained with respect to the total mass of the component which comprises the said base material layer (B) in an olefin polymer (B1) from the point with favorable affinity with the adhesion layer (A) which comprises the surface protection film of this invention. It is preferable to.

As said olefin polymer (B1), an ethylene polymer, a crystalline propylene polymer, etc. are mentioned.

As said ethylene polymer, 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. When these ethylene polymers are used as a base material layer (B), when cut-processing a to-be-adhered body in the state in which the surface protection film was affixed on the to-be-adhered body, a surface protection film is cut | disconnected neatly, stringiness, fluff, etc. The favorable cutting property which does not produce the external appearance defect of expresses. Moreover, since heat resistance is favorable among these, the low density polyethylene, the high density polyethylene, or the mixed resin of the low density polyethylene and the high density polyethylene is preferable.

Moreover, it is preferable that these ethylene polymers are 0.5-30.0 g / 10min of MFR (190 degreeC), since extrusion molding becomes easy, More preferably, MFR is 2.0-15.0 g / 10min. Moreover, when these ethylene polymers have melting | fusing points of 90-135 degreeC, even if they are exposed to a high temperature environment by drying, heat molding, etc. after adhering to a to-be-adhered body, since there is little shrinkage of a film, the lifting and peeling from a to-be-adhered body, and avoiding Since the curvature etc. of a complex can be suppressed, it is preferable, More preferably, melting | fusing point is a thing of 105-130 degreeC.

Examples of the crystalline propylene polymers include propylene homopolymers, propylene-ethylene copolymers, propylene-butene-1 copolymers, propylene-ethylene-butene-1 copolymers, and metallocene catalyst-based polypropylenes. have. These may be used independently, respectively and may be used together. When using these crystalline propylene polymers as a base material layer (B), the heat resistance of a surface protection film improves and it can be used suitably for the use etc. which are heat-processed after sticking. Moreover, it is preferable to use a metallocene catalyst polypropylene among these. This is because the metallocene catalyst-based polypropylene has high homogeneity in molecular weight distribution and composition distribution, and has low content of low molecular weight components. Therefore, when used as a main component of the base material layer (B), the adherend due to bleeding of low molecular weight components This is because contamination of the surface is reduced. In addition, in this application, crystallinity means having a peak of 0.5 J / g or more in the range of 95-250 degreeC in DSC (differential scanning calorimetry). The metallocene catalyst polypropylene may be a propylene homopolymer or a copolymer of propylene with another α-olefin.

Moreover, as for these crystalline propylene polymers, it is preferable that MFR (230 degreeC) is 0.5-30.0 g / 10min, and melting | fusing point is 120-165 degreeC, More preferably, MFR (230 degreeC) is 2.0-15.0 g / 10 minutes, melting point of 125 ~ 162 ℃. If the MFR and melting point are within this range, there is little shrinkage of the film even when exposed to a high temperature environment by drying, heat molding, or the like after being adhered to the adherend, so that lifting or peeling from the adherend, warpage of the adherend, etc. can be suppressed. It is preferable and the film-forming property of laminated | multilayer film also improves.

The surface protection film of this invention may be comprised from two layers of the adhesion layer (A) and base material layer (B) mentioned above, and may provide surface layer (C) in addition to these. At this time, the surface layer (C) is provided on the surface on the opposite side to the adhesive layer (A) on the base material layer (B). Resin which becomes a main component of the surface layer (C) used for the surface protection film of this invention is a thermoplastic resin, Although it will not specifically limit if coextrusion with an adhesion layer (A) and a base material layer (B) is possible, but it is the said base material layer It is preferable to contain 65 mass% or more of olefin polymers (C1) with respect to the total mass of the component which comprises the said surface layer (C) from a point with favorable affinity with (B). In particular, when the main component of the base layer (B) is an ethylene polymer, it is more preferable to use an ethylene polymer, and when the main component of the base layer (B) is a crystalline propylene polymer, a crystalline propylene polymer is used. .

As an ethylene polymer used as a resin component of a surface layer (C), the same thing as the ethylene polymer used for the said base material layer (B) is mentioned. Moreover, by selecting an ethylene polymer as the resin component of the surface layer (C), the high cutting property of the finally obtained surface protection film expresses like the case where an ethylene polymer is used as the resin component of a base material layer (B).

Among the ethylene polymers used as the resin component 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 shell shape. By making the surface of the surface layer (C) into a shell shape, even when the adhesive force of the adhesion layer (A) is designed strongly, blocking can be reduced. Moreover, when high density polyethylene is used together with low density polyethylene, 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 and a propylene ethylene block copolymer is used as a resin component of the said surface layer (C), the surface of the surface layer (C) can be modified in a pear-shell shape. The propylene-ethylene block copolymer may be a resin obtained by block polymerization of propylene and ethylene. For example, the propylene-ethylene block air obtained by polymerization of ethylene or polymerization of ethylene and propylene in the presence of a propylene homopolymer. Coalescence, etc. are mentioned. Among these, propylene-ethylene block copolymers having an ethylene-derived component content of 8 to 20% by mass are preferable, and the propylene-ethylene component having a content of ethylene-derived components of 10 to 15% by mass is preferable. It is more preferable if it is a block copolymer. The MFR (230 ° C) of the mixed resin of the ethylene-based polymer and the propylene-ethylene block copolymer is preferably in the range of 4 to 12 g / 10 minutes in terms of easy extrusion processing, and is in the range of 6 to 10 g / 10 minutes. It is more preferable that is. Likewise, it is the art that the density of the mixed resin is in the range of 0.890 ~ 0.910g / cm ³ more preferably preferred, and a range of 0.895 ~ 0.905g / cm ³ in the extruding process easy point.

As a crystalline propylene polymer used as a resin component of a surface layer (C), the same thing as the crystalline propylene polymer used as a resin component of the said base material layer (B) is mentioned. In addition, by selecting the crystalline propylene polymer as the resin component of the surface layer (C), the high heat resistance of the finally obtained surface protection film is expressed as in the case of using the crystalline propylene polymer as the resin component of the base layer (B). do.

As the resin component of the surface layer (C), when a mixed resin of the crystalline propylene polymer and the propylene-ethylene copolymer elastomer (hereinafter referred to as "EPR") is used, the surface layer (C) is easily formed in a pear-shell shape. Can be modified. As the crystalline propylene polymer used at this time, a propylene homopolymer having high versatility (hereinafter referred to as "HOPP") is preferable. On the other hand, the EPR used at this time is preferably in the range of 400,000 to 1 million in terms of weight average molecular weight, in that it forms irregularities on the surface of the film and can modify the surface into a pear shell shape. It is more preferable. Moreover, it is preferable that the content rate of EPR in mixed resin is the range of 5-35 mass% in the point which can modify a film surface homogeneously in pear-shell shape. It is preferable that MFR (230 degreeC) of the mixed resin of this crystalline propylene polymer and EPR is 0.5-15 g / 10min in the point which is easy to extrusion process. In addition, the weight average molecular weight of the said EPR calculates | requires and calculates the component extracted by the cross fractionation method at 40 degreeC using the ortho-dichlorobenzene as a solvent, by GPC (gel permeation chromatography). In addition, the content rate of EPR in the said mixed resin is calculated | required by the extraction amount of the EPR extracted by the cross fractionation method at 40 degreeC using ortho-dichlorobenzene as the solvent for this mixed resin.

There is no restriction | limiting in particular in the manufacturing method of the mixed resin of the said crystalline propylene-type polymer and EPR, As a specific example, for example, solution polymerization of a propylene homopolymer and ethylene-propylene copolymerization elastomer separately using a Ziegler-type catalyst is carried out. After producing by the method, slurry polymerization method, gas phase polymerization method, etc., both are mixed with a kneader, or the two-stage polymerization method produces a propylene homopolymer in the first stage, and in the presence of this polymer in the second stage. The method of generating an EPR, etc. are mentioned.

The Ziegler-type catalyst is a so-called Ziegler-Natta catalyst, and an organic metal compound such as a carrier supported catalyst and an organoaluminum compound obtained by supporting a transition metal compound such as a titanium-containing compound or a carrier such as a magnesium compound. The combination of the promoters of these, etc. are mentioned.

It is preferable that the surface protection film of this invention is 20-120 micrometers in total film thickness. If the thickness of all films is this range, workability, such as sticking and peeling, will become favorable. Moreover, 3-30 micrometers is preferable and, as for the thickness of an adhesion layer (A), More preferably, it is 5-25 micrometers. When the thickness of the adhesion layer (A) is this range, in addition to the said adhesive characteristic, the film-forming property of a laminated film will 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 a surface layer, More preferably, it is 5-20 micrometers. If the thickness of the surface layer is within this range, the heat resistance and the film-forming property of the laminated film are good.

Although it does not specifically limit as a manufacturing method of the surface protection film of this invention, if it is a co-extrusion lamination method, For example, the resin used for each resin layer is melt | dissolved using two or more extruders, and a multi-manifold method and a 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-chill roll method, between the rubber touch roll, a steel belt, etc., the melt-laminated film may be nipped and cooled.

In addition, it is good also as a surface protection film of this invention as a uniaxial stretched film or a biaxially stretched film. By extending | stretching in at least one axial direction, a base material layer is orientation crystallized and structural stabilization by heat setting is attained. This is preferable because the heat resistance is improved and the aging change of the adhesive force becomes smaller.

Moreover, you may add suitably a lubricating agent, an antiblocking agent, an ultraviolet absorber, a light stabilizer, an antistatic agent, an antifog additive, a coloring agent, etc. in the range which does not impair the effect of this invention. As these additives, it is preferable to use various additives for olefin resins.

[Example]

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

Example 1

As the resin for the surface layer, a propylene-based mixed resin (resin composed of propylene homopolymer and EPR, MFR (230 ° C.): 4.0 g / 10 min, content of EPR: 11 mass%, weight average molecular weight 550,000 of EPR) was used. As a resin for the base layer, a metallocene catalyst-based propylene-ethylene random copolymer [density: 0.900 g / cm ³ , MFR (230 ° C., 21.18 N): 7.0 g / 10 min, content rate of ethylene monomer unit: 3.5 mass%; Hereinafter, "metallocene catalyst-based COPP" is used. As a resin for the adhesive layer, "Dynaron 6200P" manufactured by JSR Corporation (density: 0.88 g / cm ³ , MFR (230 ° C): 2.5 g / 10 Minutes: hereinafter referred to as "CEBC" 10 parts by mass and linear low density polyethylene [density: 0.902 g / cm ³ , MFR (190 ° C): 3.0 g / 10 min; Hereafter, referred to as "LLDPE (1)"] Using a mixture of 90 parts by mass, it is supplied to the surface layer extruder (diameter 30 mm), the base layer extruder (diameter 40 mm) and the adhesive layer extruder (diameter 30 mm), respectively, to the coextrusion method. By extrusion at a extrusion temperature of 250 ° C. so that the surface layer had a thickness of 10 μm, the base layer had a thickness of 30 μm, and the adhesive layer had a thickness of 10 μm, 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)

As a resin for adhesion layers, the surface protection film of Example 2 was obtained like Example 1 except having used the mixture of 30 mass parts and 70 mass parts of LLDPE (1) CEBC.

Example 3

As resin for adhesion layers, 10 mass parts and linear low density polyethylene [density: 0.920 g / cm <^3> , MFR (190 degreeC): 3.0 g / 10min, CEBC; Hereinafter referred to as "LLDPE (2)". The surface protective film of Example 3 was obtained like Example 1 except having used the mixture of 90 mass parts.

Example 4

As a resin for adhesion layers, the surface protection film of Example 4 was obtained like Example 1 except having used the mixture of 30 mass parts and 70 mass parts of LLDPE (2) CEBC.

(Example 5)

The surface protection film of Example 5 was obtained like Example 4 except having used HOPP [density: 0.900 g / cm <^3> , MFR (230 degreeC): 8.0 g / 10min] as resin for base material layers.

Example 6

As the resin for the surface layer, a propylene-based mixed resin (resin composed of propylene homopolymer and EPR, MFR (230 ° C.): 4.0 g / 10 min, content of EPR: 30 mass%, weight average molecular weight 550,000 of EPR) was used. The surface protection film of Example 6 was obtained like Example 1 except having used the mixture of 50 mass parts of CEBC and 50 mass parts of LLDPE (2) as resin for adhesion layers.

(Example 7)

As a resin for adhesion layers, the surface protection film of Example 7 was obtained like Example 6 except having used the mixture of 70 mass parts and 30 mass parts of LLDPE (2) CEBC.

(Example 8)

As a base material layer, the surface protection film of Example 8 was obtained like Example 7 except having used HOPP.

(Example 9)

As resin for surface layer and resin for base material layers, Low density polyethylene [density: 0.920 g / cm <^3> , MFR (190 degreeC): 6g / 10min; Hereinafter, "LDPE (1)"] is used, and as the resin for the adhesion layer, a mixture of 10 parts by mass of CEBC and 90 parts by mass of LLDPE (1) is used, the thickness of the surface layer is 14 µm, and the thickness of the substrate layer is 42. The surface protection film of Example 9 was obtained like Example 1 except having extruded so that the thickness of micrometer and the adhesion layer might be set to 14 micrometers.

(Example 10)

As a resin for adhesion layers, the surface protection film of Example 10 was obtained like Example 9 except having used the mixture of 30 mass parts and 70 mass parts of LLDPE (1) CEBC.

(Example 11)

As a resin for adhesion layers, the surface protection film of Example 11 was obtained like Example 9 except having used the mixture of 10 mass parts and 90 mass parts of LLDPE (2) CEBC.

Example 12

As a resin for adhesion layers, the surface protection film of Example 12 was obtained like Example 9 except having used the mixture of 30 mass parts and 70 mass parts of LLDPE (2) CEBC.

Example 13

As resin for surface layer, 50 mass parts of LDPE (1) and high density polyethylene [density: 0.960 g / cm <^3> , MFR (190 degreeC): 5.5 g / 10min; Hereinafter, "HDPE (1)" is used in the same manner as in Example 9 except that 50 parts by mass of a mixture is used, and 50 parts by mass of CEBC and 50 parts by mass of LLDPE (2) are used as the resin for the adhesive layer. The surface protection film of 13 was obtained.

Example 14

The surface layer resin was not used, and as the resin for the adhesive layer, a mixture of 70 parts by mass of CEBC and 30 parts by mass of LLDPE (2) was used, except that the thickness of the substrate layer was 56 µm and the thickness of the adhesion layer was 14 µm. Obtained the surface protection film of Example 14 similarly to Example 9.

Example 15

As the resin for the base layer, low density polyethylene (density: 0.902 g / cm ³ , MFR (190 ° C., 21.18 N): 4 g / 10 min; hereinafter “LDPE (2)”) and high density polyethylene (density: 0.960 g / cm ³ , MFR (190 ° C, 21.18N): 13 g / 10 min; below "HDPE (2)" was mixed so as to be 50/50 by mass ratio, and as resin for adhesion layers, 30 mass parts of CEBC and 70 mass parts of LLDPE (2) The mixture was supplied to an extruder for base layer (50 mm diameter) and an extruder for 40 mm (40 mm diameter) layers, respectively, and the thickness of the base layer was 64 μm from the T-die at an extrusion temperature of 250 ° C. by the coextrusion method. The surface protection film of Example 15 was obtained like Example 1 except having extruded so that thickness might be 16 micrometers.

Example 16

As the resin for the surface layer, the LDPE (2) and the propylene-ethylene block copolymer were mixed in a mass ratio of 95/5, and as the resin for the substrate, the LDPE (2) and the HDPE (2) were mixed in a mass ratio of 50/50. As the resin for the adhesive layer, CEBC and linear low density polyethylene (density: 0.902 g / cm ³ , MFR (190 ° C, 21.18N): 6 g / 10 min; hereinafter referred to as "LLDPE (3)") The mixture of furnace 5/95 was supplied to the surface layer extruder (diameter 50 mm), the base layer extruder (diameter 50 mm), and the adhesion layer extruder (diameter 40 mm), respectively, and co-extruded at an extrusion temperature of 250 ° C. at T-. The surface protection film of Example 16 was obtained like Example 1 except having extruded so that the thickness of a surface layer might be 16 micrometers, the thickness of a base material layer is 48 micrometers, and the thickness of an adhesion layer from a die | dye.

(Example 17)

HOPP and the propylene-ethylene block copolymer were mixed at a mass ratio of 95/5 as the resin for the surface layer, and a metallocene catalyst-based COPP was used as the resin for the base layer, and CEBC and LLDPE (2) were used as the resin for the adhesive layer. A surface protective film of Example 17 was obtained in the same manner as in Example 16 except that the mixture of 30/70 was used.

(Example 18)

As a resin for adhesion layers, the surface protection film of Example 18 was obtained like Example 16 except having used the mixture of CEBC, LLDPE (3), and metallocene catalyst type COPP by mass ratio 25/70/5.

Example 19

As a resin for adhesion layers, the surface protection film of Example 19 was obtained like Example 15 except having used the mixture of CEBC, LLDPE (2), and metallocene catalyst type COPP by mass ratio 40/40/20.

Example 20

As a resin for adhesion layers, the surface protection film of Example 20 was obtained like Example 16 except having used the mixture of CEBC, LLDPE (2), and metallocene catalyst type COPP by mass ratio 40/35/25.

(Example 21)

As a resin for an adhesion layer, the surface protection film of Example 21 was obtained like Example 16 except having used the mixture of CEBC, LLDPE (2), and metallocene catalyst type COPP by mass ratio 40/30/30.

(Example 22)

As a resin for adhesion layers, the surface protection film of Example 22 was obtained like Example 16 except having used the mixture of 35/40/25 by mass ratio of CEBC, LLDPE (2), and metallocene catalyst type COPP.

(Example 23)

As a resin for adhesion layers, the surface protection film of Example 23 was obtained like Example 16 except having used the mixture of CEBC, LLDPE (3), and metallocene catalyst type COPP by mass ratio 25/45/30.

Example 24

As a resin for adhesion layers, the surface protection film of Example 24 was obtained like Example 16 except having used the mixture of CEBC, LLDPE (3), and metallocene catalyst type COPP by mass ratio 25/50/25.

(Example 25)

As a resin for adhesion layers, the surface protection film of Example 25 was obtained like Example 16 except having used the mixture of CEBC, LLDPE (2), and metallocene catalyst type COPP by mass ratio 40/10/50.

Example 26

As a resin for adhesion layers, the surface protection film of Example 26 was obtained like Example 17 except having used the mixture of CEBC, LLDPE (2), and metallocene catalyst type COPP by mass ratio 40/35/25.

Example 27

As a resin for adhesion layers, the surface protection film of Example 27 was obtained like Example 17 except having used the mixture of CEBC, LLDPE (2), and metallocene catalyst type COPP by mass ratio 40/30/30.

Example 28

As a resin for adhesion layers, the surface protection film of Example 28 was obtained like Example 17 except having used the mixture of 25/50/25 by mass ratio of CEBC, LLDPE (3), and a metallocene catalyst system COPP.

(Example 29)

As a resin for adhesion layers, the surface protection film of Example 29 was obtained like Example 16 except having used the mixture of CEBC, LLDPE (2), and metallocene catalyst type COPP by mass ratio 15/65/20.

(Example 30)

As a resin for adhesion layers, the surface protection film of Example 30 was obtained like Example 16 except having used the mixture of CEBC, LLDPE (2), and metallocene catalyst type COPP by mass ratio 30/60/10.

(Comparative Example 1)

Comparative resin 1 was the same as in Example 6, except that 57 parts by mass of the amorphous propylene-butene-1 copolymer, 3 parts by mass of the crystalline propylene-butene-1 copolymer and 40 parts by mass of CEBC were used as the resin for the adhesive layer. The surface protection film of was obtained.

(Comparative Example 2)

Comparative resin 2 was prepared in the same manner as in Example 6 except that 49.4 parts by mass of the amorphous propylene-butene-1 copolymer, 10.6 parts by mass of the crystalline propylene-butene-1 copolymer and 40 parts by mass of CEBC were used as the resin for the adhesive layer. The surface protection film of was obtained.

(Comparative Example 3)

As the resin for the adhesion layer, except that 50 parts by mass of a styrene-ethylene-propylene-styrene block copolymer ("Septon 2063" manufactured by KKK Co., Ltd .; hereafter referred to as "SEPS") and 50 parts by mass of LLDPE (2) were used. In the same manner as in Example 6, the surface protective film of Comparative Example 3 was obtained.

(Comparative Example 4)

As a resin for adhesion layers, the surface protection film of the comparative example 4 was obtained like Example 16 except having used the mixture of CEBC, LLDPE (2), and metallocene catalyst type COPP by mass ratio 30/10/60.

(Comparative Example 5)

As the resin for the adhesion layer, the surface protective film of Comparative Example 5 was prepared in the same manner as in Example 16 except that the mixture of CEBC, metallocene catalyst-based COPP, and amorphous propylene-butene-1 copolymer was used in a mass ratio of 40/10/50. Got it.

(Comparative Example 6)

As a resin for adhesion layers, the surface protection film of the comparative example 6 was obtained like Example 16 except having used the mixture of CEBC and metallocene catalyst type COPP by mass ratio 70/30.

(Evaluation method of the surface protection film obtained by the Example and the comparative example)

[Measurement of Adhesive Force]

In the constant temperature chamber of 23 degreeC and 50% RH, based on the adhesive force evaluation method of JISZ0237: 2000, the surface protection film obtained above was made into the acrylic plate (mirror surface finish, Mitsubishi Rayon Corporation) of thickness 2mm. Acrylic light ”). After leaving the acrylic plate on which the film is stuck for 24 hours in a constant temperature room at 23 ° C, using a tensile tester (manufactured by A & D, Co., Ltd.), the film was peeled in the direction of 180 ° at a speed of 300 mm / min to measure the initial adhesive force. did. 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.

[Evaluation of Adhesiveness]

When measuring the said adhesive force, the adhesion | attachment state to the acryl plate of the surface protection film affixed on the acryl plate was visually confirmed, and adhesiveness was evaluated by the following reference | standard.

○: Maintaining uniform adhesion to the acrylic plate surface.

X: The initial stage adhesive force was insufficient, and uniform adhesiveness was not maintained but some thing floated.

[Evaluation of pool voice]

In the constant temperature room of 23 degreeC and 50% RH, the surface protection film was made of the acrylic plate (mirror surface finish, "Acrylic light" made by Mitsubishi Rayon Corporation) of 15cm in height X 5cm in a method based on JISZ0237: 2000. Sticking to the front. The acrylic plate to which the film affixed was left still in a 60 degreeC dryer for 3 days, and then cooled in a 23 degreeC constant temperature room for 1 hour. From the cooled test piece, the film was peeled off at high speed in the 180 ° direction, visually confirmed the contamination state on the surface of the acrylic plate, and evaluation of looseness was performed based on the following criteria.

○: No contamination such as cloudy, white stripe, foreign material on the surface of acrylic plate

(Triangle | delta): A thing with practical use, although there exists some contamination, such as a cloudy, a white stripe, and a foreign material, on an acrylic board surface.

X: The surface of an acryl board has some contamination, such as a cloudiness, a white stripe, and a foreign material, and is unsuitable for practical use

[Measurement of Wetting Tension of Acrylic Plate Surface]

Wetting tension of the acrylic plate surface by the method based on JIS K6768: 1999, using the test piece before the film sticking (the test piece which wash | cleaned the surface of an acryl plate with alcohol, and dried) and the test piece after film peeling used in the said evaluation of the said remanence. Was measured. The wet tension of the test piece before film sticking was 40 mN / m.

[Printing titration evaluation after surface protection film peeling]

Using the measured value of the wet tension on the surface of the acrylic plate, the drop width ((wet tension of the test piece before film adhesion: 40 mN / m)-(wet tension of the test piece after film peeling)] of the wet tension was printed after the protective film peeling. It evaluated as a substitute evaluation of aptitude. In addition, evaluation criteria are as follows.

(Circle): The fall width of wet tension is 2 mN / m or less

X: Falling width of wet tension exceeds 2 mN / m

[Evaluation of Blocking Resistance]

The obtained surface protection film was cut out to the magnitude | size (A297mm * 210mm in width) 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-forming might correspond. After stacking 10 pieces of cut-out film, the upper and lower parts were sandwiched by a plate of A4 size and a thickness of 3mm vinyl chloride, a weight of 5 kg was put up, and stored in a 40 ° C. dryer for 14 days. Kept for 1 hour. 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 (D &amp; D), and the blocking force was measured. 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

[Measurement of Adhesive Forces Between Adhesive Surfaces]

In the constant temperature chamber of 23 degreeC and 50% RH, the adhesive surfaces of two surface protection films consisting of 15 cm x 25 mm in width were stuck by the method based on JISZ0237: 2000. After the adhered film was allowed to stand for 30 minutes in a 23 ° C. constant temperature room, the film was peeled in a 180 ° direction at a speed of 300 mm / min using a tensile tester (manufactured by KK & D., Inc.) to improve adhesion between the adhesive surfaces. Measured.

[Adhesive Surface States after Adhesive and Peeling Between Adhesive Surfaces]

In the constant temperature chamber of 23 degreeC and 50% RH, the adhesive surfaces of two surface protection films consisting of 15 cm x 25 mm in width were stuck by the method based on JISZ0237: 2000. After sticking the film to stand in a 23 degreeC constant temperature room for 30 minutes, it peeled off at high speed, visually confirmed the situation of the adhesive surface, and evaluated the adhesive surface state on the following references | standards.

○: No whitening or surface roughness on the adhesive surface

(Triangle | delta): Whitening or surface roughness generate | occur | produced on an adhesive surface, but what is suitable for practical use

X: Whitening and surface roughness are seen on an adhesive surface, and are unsuitable for practical use.

The result of having performed each said evaluation is described in the following table | surfaces. Moreover, the said location is blank about the surface protection film which does not provide the surface layer.

[Table 1]

TABLE 2

[Table 3]

[Table 4]

TABLE 5

TABLE 6

[More on stickiness]

The strength and weakness of the adhesive force of the surface protection film obtained in each Example are mainly caused by the difference of an adhesion layer, and can take various values according to the composition of an adhesion layer, In either case, an initial value and after "50 degreeC * 1 day There is no big difference in the value of 」and there is little adhesion increase. On the other hand, the surface protection film obtained by each comparative example has a big adhesion improvement compared with an Example.

[Contamination of the surface of the adherend after peeling the surface protective film]

In the surface protection film obtained by each Example, the looseness to the to-be-adhered body after film peeling could not be confirmed visually. Moreover, the fall of the wet tension of the to-be-adhered body surface before film sticking and after film peeling was small, and the contamination of the to-be-adhered body surface was able to be minimized to the extent that printability is not reduced. On the other hand, in the surface protection film obtained by each comparative example, it can confirm visually that the exfoliation to the to-be-adhered body after film peeling is carried out, and the evaluation result that the printability of the to-be-adhered body surface after film peeling falls compared with each Example Was obtained.

[Adhesion between Adhesive Surfaces]

In using a propylene polymer further together in an adhesion layer, peeling is easy even when adhesive surfaces adhere | attach, and it does not produce a roughness etc. in an adhesion surface, and detachment of a surface protection film is carried out in the middle of a manufacturing process. Also in the usage method performed, the surface protection film of this invention can be used.

[Industrial Availability]

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 matter which can be seen by eye is not recognized, and the decrease in the wetting tension of 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 to which secondary processing, such as printing, is performed.

Claims (20)

As a surface protection film which laminated | stacked the adhesion layer (A) and the base material layer (B), the said adhesion layer (A),
50 mass of the block copolymer (A1) having a crystalline olefin block and linear low density polyethylene (A2) having a density of 0.880 to 0.938 g / cm ³ with respect to the total mass of the components constituting the adhesive layer (A). % Or more, and
Block copolymer (A1) having a crystalline olefin block and 5 to 80% by mass of the total mass of the linear low density polyethylene (A2) having a density of 0.880 to 0.938 g / cm ³ have a crystalline olefin block. It is coalescence (A1), The surface protection film characterized by the above-mentioned. The method of claim 1,
The block copolymer (A1) which has the said crystalline olefin block is a crystalline olefin ethylene butylene copolymer crystalline olefin block copolymer (CEBC). The method of claim 1,
The surface protection film which further contains a propylene polymer (A3) in an adhesion layer (A). The method of claim 3,
The propylene-based polymer (A3) is a metallocene catalyst-based polypropylene. The method of claim 2,
The surface protection film which further contains a propylene polymer (A3) in an adhesion layer (A). The method of claim 5,
The propylene-based polymer (A3) is a metallocene catalyst-based polypropylene. The method of claim 3,
The use ratio (A1) of each component in 100 mass parts of said block copolymer (A1), the said linear low density polyethylene (A2), and the said propylene polymer (A3) in total is 10- Surface protection film which is 50: 10-70: 10-50. The method of claim 5,
The use ratio (A1) of each component in 100 mass parts of said block copolymer (A1), and said linear low density polyethylene (A2) and the said propylene polymer (A3) in total is 10 Surface protection film which is-50:10-70: 10-50. The method of claim 1,
The said base material layer (B) contains 65 mass% or more of olefin type polymers (B1) with respect to the total mass of the component which comprises the said base material layer (B). 10. The method of claim 9,
The said olefin polymer (B1) is a surface protection film which is 1 or more types of olefin polymers chosen from the group which consists of a low density polyethylene, a high density polyethylene, and a crystalline propylene polymer. The method of claim 1,
The surface protection film which provided the surface layer (C) on the base material layer (B) on the opposite side to the said adhesion layer (A). The method of claim 11,
The surface protection film in which the said surface layer (C) contains an olefin type polymer (C1) 65 mass% or more with respect to the total mass of the component which comprises the said surface layer (C). The method of claim 12,
The said olefin polymer (C1) is a surface protection film which is 1 or more types of olefin polymers chosen from the group which consists of a low density polyethylene, a high density polyethylene, and a propylene homopolymer. The method of claim 12,
The said olefin polymer (C1) is a surface protection film which is a mixed resin of 1 or more types of olefin polymers chosen from the group which consists of a low density polyethylene, a high density polyethylene, and a propylene homopolymer, and a propylene ethylene block copolymer. The method of claim 3,
The said base material layer (B) contains 65 mass% or more of olefin type polymers (B1) with respect to the total mass of the component which comprises the said base material layer (B). 16. The method of claim 15,
The said olefin polymer (B1) is a surface protection film which is 1 or more types of olefin polymers chosen from the group which consists of a low density polyethylene, a high density polyethylene, and a crystalline propylene polymer. The method of claim 3,
The surface protection film which provided the surface layer (C) on the base material layer (B) on the opposite side to the said adhesion layer (A). The method of claim 17,
The surface protection film in which the said surface layer (C) contains an olefin type polymer (C1) 65 mass% or more with respect to the total mass of the component which comprises the said surface layer (C). The method of claim 18,
The said olefin polymer (C1) is a surface protection film which is 1 or more types of olefin polymers chosen from the group which consists of a low density polyethylene, a high density polyethylene, and a propylene homopolymer. The method of claim 18,
The said olefin polymer (C1) is a surface protection film which is a mixed resin of 1 or more types of olefin polymers chosen from the group which consists of a low density polyethylene, a high density polyethylene, and a propylene homopolymer, and a propylene ethylene block copolymer.