JP5031320B2 - Surface protection film - Google Patents

Description

  The present invention relates to a surface protective film used for optical products, building materials, automobile parts and the like. More specifically, the present invention relates to a surface protective film that is excellent in adhesive properties, transparency, and heat resistance, has little contamination to an adherend, and is easy to be drawn out from a roll.

  The surface protective film is used by sticking to adherends such as resin products, metal products, glass products, etc. mainly for building materials and optical applications, and prevents them from being scratched or contaminated during transport, storage or processing. Plays. These surface protective films generally comprise a non-adhesive surface layer and an adhesive layer for adhering to the adherend. The surface layer is usually formed from a polyolefin such as polyethylene or polypropylene, a polyester such as polyethylene terephthalate, or a vinyl polymer such as polyvinyl chloride.

  In recent years, development of members used for liquid crystal screens, plasma displays (PDP), rear projection screens, and so on, so-called optical products, has been progressing. The surface protective film for protecting these optical products is not only scratched or mixed with foreign matter, but also transparent so that product inspection can be performed with the surface protective film applied, and even when applied at high temperatures. Properties such as the development of adhesive strength are desired.

  On the other hand, when the surface protective film is used for building materials or automotive parts, it may be thermoformed with the surface protective film attached, and high heat resistance is required.

  In addition, since a surface protective film having a relatively high adhesive strength is difficult to be fed out from a roll-shaped product, it is formed into a roll shape with a release film bonded to an adhesive layer, and applied to an adherend. The release film is peeled off and used. When such a process is employed, a large amount of waste is generated, and thus a surface protective film that can be easily fed out from a roll without a release film is required.

Japanese Unexamined Patent Application Publication No. 2006-116769 discloses a surface protective film mainly composed of a polyethylene component. However, although the method according to the publication can be applied to some use members, the adhesive strength is low and the transparency is insufficient, and the use of the adherend is limited.
JP 2006-116769 A

  The present invention has characteristics required as a surface protective film for protecting optical products, building material products and automobile parts during storage, transportation, processing and inspection, in particular, adhesive properties, transparency, heat resistance and feeding from a roll. It is in providing the surface protection film excellent in property.

As a result of intensive studies in view of the above problems, the present inventors have found that the above problems can be solved by a surface protective film having a surface layer made of a specific resin composition, and have completed the present invention.
That is, the present invention
1. It is a surface protective film from at least two layers of the surface layer (A) and the adhesive layer (X), and the surface layer (A) is 2 to 98 % by weight of butene-based (co) polymer (a) and having 5 or more carbon atoms. an olefin (co) polymer (b) based on α-olefin as a main component and formed from a composition comprising 2 to 98% by weight , and
Surface protective film to the olefin (co) polymer (b) is 4-methylpentene-1-based (co) polymer der wherein Rukoto,
2 . The surface protective film according to 1 , wherein the adhesive layer (X) is formed from an olefin-based elastomer and / or a styrene-based elastomer,
3 . The surface protective film according to 1 or 2, which is a multilayer film obtained by extrusion molding at least two layers of a surface layer (A) and an adhesive layer (X) from a T-die ,
4). The surface protective film according to any one of 1 to 3, comprising an intermediate layer between the surface layer (A) and the adhesive layer (X),
5.4 A laminate of the surface protective film according to 5.4, wherein the surface layer (A) and the adhesive layer (X) are in contact with each other,
A roll of the surface protective film according to 6.4, wherein the surface layer (A) and the adhesive layer (X) are in contact with each other.

  The surface protective film of the present invention is excellent in adhesive properties, transparency, feedability (rewinding force), and heat resistance, and has an extremely high industrial value as a protective film for optical applications, building material applications, and automotive parts applications.

Next, the present invention will be described in detail.
The surface protective film of the present invention comprises at least two layers of a surface layer (A) and an adhesive layer (X).

  The surface layer (A) is formed from a composition comprising a butene-based (co) polymer (a) and an olefin (co) polymer (b) mainly composed of an α-olefin having 5 or more carbon atoms.

  The butene-based (co) polymer (a) is a 1-butene homopolymer, a random or block copolymer of 1-butene and ethylene or an α-olefin having 3 to 20 carbon atoms (excluding 1-butene). Can be mentioned.

  In the random or block copolymer, the α-olefin having 3 to 20 carbon atoms (excluding 1-butene) includes propylene, 4-methylpentene-1, 1-hexene, 1-octene, 1-decene, 1-decene, Examples include dodecene.

  The butene-based (co) polymer (a) has a melting point of 40 to 150 ° C, preferably 50 to 140 ° C, more preferably 70 to 135 ° C. Heat resistance improves because melting | fusing point exists in such a preferable range. Here, the melting point is a value measured by a differential scanning calorimeter (DSC) at a temperature rising / falling rate of 10 ° C./min.

The butene-based (co) polymer (a) has a melt flow rate (hereinafter abbreviated as MFR ₁₉₀ ) measured at 190 ° C. of 0.01 to 500 g / 10 minutes, preferably 0.05 to 100 g / 10. Min, more preferably in the range of 0.1-50 g / 10 min.

  The butene-based (co) polymer (a) includes not only a solid titanium catalyst mainly composed of a solid titanium compound and an alkylaluminum compound, but also 1-butene in the presence of a metallocene compound mainly composed of a metallocene compound. It is obtained by copolymerizing 1-butene with ethylene or an α-olefin having 3 to 20 carbon atoms (excluding 1-butene).

  The olefin (co) polymer (b) contains 50 to 100 mol%, preferably 60 to 100 mol%, more preferably 70 to 100 mol% of an α-olefin having 5 or more carbon atoms. Examples of the α-olefin having 5 or more carbon atoms include 4-methylpentene-1, 1-hexene, 1-octene, 1-decene, 1-dodecene and the like, and 4-methylpentene-1 is preferable.

  Preferred examples of the olefin (co) polymer (b) include 4-methylpentene-1 homopolymer, 4-methylpentene-1 and an α-olefin having 6 to 20 carbon atoms. Examples of the α-olefin having 6 to 20 carbon atoms include 1-hexene, 1-octene, 1-decene and 1-dodecene.

  The olefin (co) polymer (b) has a melting point in the range of 150 to 300 ° C, preferably 180 to 280 ° C, more preferably 200 to 250 ° C. When the melting point is in such a preferable range, a surface protective film having good moldability and excellent heat resistance can be obtained.

The olefin (co) polymer (b) has a melt flow rate (hereinafter abbreviated as MFR ₂₆₀ ) measured at 260 ° C. of 0.1 to 500 g / 10 minutes, preferably 0.5 to 200 g / 10 minutes. More preferably, it is in the range of 1 to 100 g / 10 min.

  The surface layer (A) in the surface protective film of the present invention is formed from a composition comprising the butene-based (co) polymer (a) and the olefin (co) polymer (b).

  The proportion of the butene-based (co) polymer (a) in the composition is 2 to 100% by weight, preferably 3 to 98% by weight, more preferably 5 to 90% by weight, and the olefin (co) polymer (b ) Is 0 to 98% by weight, preferably 2 to 97% by weight, more preferably 5 to 95% by weight.

  In the composition, various additives such as an antistatic agent, a release agent, an antioxidant, a weathering agent, a crystal nucleating agent, a polyolefin, a polyester, and the like are added as long as the characteristics as the surface protective film of the present invention are not impaired. It is also possible to add resin modifiers such as polyamide and elastomer.

  The propylene-based (co) polymer (a) and the olefin (co) polymer (b), and if necessary, additives and modifiers are kneaded by, for example, a single-screw or twin-screw extruder or a feeder ruder. Although it may be further processed into a film shape, it can be directly put into a T-die molding machine equipped with an extruder to form the surface layer of the surface protective film of the present invention.

  As the pressure-sensitive adhesive layer (X) of the surface protective film of the present invention, any known pressure-sensitive adhesive used as the pressure-sensitive adhesive layer of the surface protective film can be used. From the viewpoint of damage, transfer of the adhesive to the adherend, so-called adhesive residue, an olefin-based elastomer and / or a styrene-based elastomer is preferable. More preferably, it is an olefin elastomer or a composition comprising an olefin elastomer and a styrene elastomer.

  As the olefin elastomer, the melting point is 110 ° C. or less, preferably 100 ° C. or less, more preferably 80 ° C. or less, or an α-olefin polymer or copolymer having 2 to 20 carbon atoms in which no melting point is observed, or ethylene and unsaturated. It is a copolymer with a carboxylic acid or an unsaturated carboxylic acid ester. Specifically, ethylene / propylene copolymer, ethylene / 1-butene copolymer, ethylene / 1-hexene copolymer, ethylene / 4-methylpentene-1 copolymer, ethylene / 1-octene copolymer , Propylene homopolymer, propylene / ethylene copolymer, propylene / ethylene / 1-butene copolymer, 1-butene homopolymer, 1-butene / ethylene copolymer, 1-butene / propylene copolymer, 4-methylpentene-1 homopolymer, 4-methylpentene-1 / propylene copolymer, 4-methylpentene-1 / 1-butene copolymer, 4-methylpentene-1 / propylene / 1-butene copolymer Polymer, propylene / 1-butene copolymer, ethylene / vinyl acetate copolymer, ethylene / methacrylic acid copolymer, ethylene / methyl methacrylate copolymer It can be mentioned. From the viewpoint of stability of adhesive strength with time, a propylene homopolymer, a propylene / ethylene copolymer, a propylene / 1-butene copolymer, and a propylene / ethylene / 1-butene copolymer are preferable.

  As the styrene elastomer, a known styrene elastomer having a polystyrene phase as a hard segment can be used. Specifically, styrene / butadiene copolymer (SBR), styrene / isoprene / styrene copolymer (SIS), styrene / butadiene / styrene copolymer (SBS), styrene / ethylene / butadiene / styrene copolymer ( SEBS), and their hydrides.

  The adhesive layer (X) in the surface protective film of the present invention can be formed by using the olefin-based elastomer and / or the styrene-based elastomer alone or by blending components having different compositions. Further, in the present invention, for the purpose of controlling the adhesive strength, and within the range not impairing the characteristics of the present invention, polyolefins such as polyethylene and polypropylene, resin modifiers such as acid-modified polyolefin, polyester and polyamide, Various additives such as an inhibitor, a crystal nucleating agent and an antioxidant may be contained.

  The above-mentioned olefin elastomer and / or styrene elastomer and, if necessary, a resin modifier or additive can be laminated with the surface layer (A) to form the surface protective film of the present invention.

  The method for laminating the surface layer (A) and the pressure-sensitive adhesive layer (X) is not particularly limited. However, known methods such as extrusion lamination and extrusion coating on a surface layer film obtained in advance by T-die molding or inflation molding. The method of laminating by the above-mentioned laminating method, the method of laminating each film by dry lamination after forming the surface layer and the adhesive layer independently into a film, etc. are mentioned. From the viewpoint of productivity, the surface layer, the adhesive layer Coextrusion molding in which each of the above components is subjected to molding in a multilayer extruder is preferred.

In the present invention, it is possible to provide at least one intermediate layer between the surface layer (A) and the adhesive layer (X). Moreover, when the adhesive force with the surface layer (A) and the pressure-sensitive adhesive layer (X) is insufficient, an adhesive or an adhesive layer may be used as the intermediate layer.
Although there is no restriction | limiting in particular as an intermediate | middle layer, Generally, crystalline polyolefins, such as a polypropylene and polyethylene with melting | fusing point of 100 degreeC or more, polyester, polyamide, polyolefin-type elastomer, etc. can be used. When the intermediate layer is used as an adhesive layer, modified polyolefin, polyolefin elastomer, styrene elastomer, polyester elastomer, or the like is used. Among these, from the viewpoint of productivity and transparency, it is preferable to use polypropylene or polyolefin elastomer as the intermediate layer.

  As thickness of the surface layer (A) in the surface protection film of this invention, it is 0.05-200 micrometers, Preferably it is 0.5-100 micrometers, More preferably, it is 1-30 micrometers, More preferably, it is 1-15 micrometers. As thickness of adhesion layer (X), it is 0.05-50 micrometers, Preferably it is 0.3-40 micrometers, More preferably, it is 0.5-30 micrometers.

  Therefore, the thickness of the surface protective film of the present invention is 0.1 to 500 μm, preferably 0.5 to 400 μm, more preferably 3 to 300 μm, including an intermediate layer that may be provided if necessary.

  By using the surface layer (A), the pressure-sensitive adhesive layer (X), and the intermediate layer in the preferable form, a surface protective film excellent in transparency can be obtained, and can be suitably used particularly for optical applications.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these Examples.

[Evaluation method]
Adhesive strength: Acrylic plate is cut into a width of 50 mm and a length of 125 mm, and is attached to this test plate using a pressure roll laminator. Next, the peel force when peeled at a speed of 300 mm / min (180 degree peel) is measured, and the peel force per 25 mm width is defined as the adhesive strength (N / 25 mm). Here, the measurement of sticking and peeling force was performed on the conditions of 23 degreeC.

Unwinding force: Using a roll-shaped sample, the peeling force (N / 25 mm) when being peeled off from the roll at a speed of 300 mm / min is measured and used as the unwinding force.

Haze: Measured with a film having a thickness of 50 μm according to JIS K7105.

Example 1
The following resin composition is supplied to a three-layer three-layer T-die molding machine having a die width of 500 mm, which is equipped with a 30 mmφ single screw extruder for the surface layer and the adhesive layer and a 40 mmφ single screw extruder for the intermediate layer, A surface protective film having a thickness of 10 μm, an adhesive layer thickness of 10 μm, an intermediate layer thickness of 30 μm, and a total thickness of 50 μm was obtained. The evaluation results of the obtained film are shown in Table-1.
Surface layer:
Homopolybutene (brand name: BL4000, melting point = 125 ° C., MFR ₁₉₀ = 1.8 g / 10 min, manufactured by Mitsui Chemicals) 30% by weight,
Poly 4-methylpentene-1 (trade name: TPX, brand name: RT18, melting point = 237 ° C., MFR ₂₆₀ = 26 g / 10 min, manufactured by Mitsui Chemicals) 30% by weight.
Middle layer:
Random polypropylene (brand name: F327, melting point = 138 ° C., MFR ₂₃₀ = 7 g / 10 min, manufactured by Prime Polypro) 100% by weight
Adhesive layer:
Propylene / ethylene / 1-butene copolymer (ethylene content 13 mol%, butene content 19 mol%, melting point not observed, MFR ₂₃₀ = 7 g / 10 min) 80 wt%
Random polypropylene (brand name: F327, melting point = 138 ° C., MFR ₂₃₀ = 7 g / 10 min, manufactured by Prime Polypro) 20% by weight

Examples 2-3, Reference Example 4 , Comparative Example 1
A surface protective film was obtained in the same manner as in Example 1 except that the resin composition of the various layers was changed to the resin composition shown in Table-1. The evaluation results of the obtained film are shown in Table-1.

h-PP;
Homo polypropylene (brand name F107BV, melting point = 160 ° C., MFR ₂₃₀ = 7 g / 10 min, manufactured by Prime Polypro)
r-PP;
Random polypropylene (brand name F327, melting point = 138 ° C., MFR ₂₃₀ = 7 g / 10 min, manufactured by Prime Polypro)
PB;
Polybutene (brand name BL4000, melting point = 125 ° C., MFR ₁₉₀ = 1.8 g / 10 min, manufactured by Mitsui Chemicals)
TPX;
Poly-4-methylpentene-1 (trade name: TPX, brand name: RT18, melting point = 237 ° C., MFR ₂₆₀ = 26 g / 10 min, manufactured by Mitsui Chemicals, Inc.)
PEBR-1;
Propylene / ethylene / 1-butene copolymer (ethylene content 13 mol%, butene content 19 mol%, melting point not observed, MFR ₂₃₀ = 7 g / 10 min)
PEBR-2;
Propylene / ethylene / 1-butene copolymer (ethylene content 12 mol%, butene content 19 mol%, no melting point observed, MFR ₂₃₀ = 7 g / 10 min)
HSBR;
Styrene elastomer (hydrogenated SBR, JSR Dynalon 1320P)

  The surface protective film of the present invention is excellent in adhesive properties, transparency, unwinding force, and heat resistance, and has an extremely high industrial utility value as a protective film for optical applications, building material applications, and automotive parts applications.

Claims (6)

It is a surface protective film from at least two layers of the surface layer (A) and the adhesive layer (X), and the surface layer (A) is 2 to 98 % by weight of butene-based (co) polymer (a) and having 5 or more carbon atoms. an olefin (co) polymer (b) based on α-olefin as a main component and formed from a composition comprising 2 to 98% by weight , and
Surface protective film to the olefin (co) polymer (b) is 4-methylpentene-1-based (co) polymer der wherein Rukoto. Adhesive layer (X) is a surface protective film according to claim 1, characterized in that it is formed from an olefin-based elastomer and / or styrene elastomer. The surface protective film according to claim 1 or 2 , wherein the surface protective film is a multilayer film obtained by extruding at least two layers of a surface layer (A) and an adhesive layer (X) from a T-die. The surface protection film as described in any one of Claims 1-3 provided with the intermediate | middle layer between the surface layer (A) and the adhesion layer (X). It is a laminated body of the surface protection film of Claim 4, Comprising: The laminated body which the said surface layer (A) and the said adhesion layer (X) contact | connect. It is a laminated body of the surface protection film of Claim 4, Comprising: The roll with which the said surface layer (A) and the said adhesion layer (X) are touching.