KR101690353B1 - Surface protection film - Google Patents

Abstract

Wherein the pressure-sensitive adhesive layer (X) comprises at least two layers of a surface layer (A) comprising a polyolefin resin and an adhesive layer (X) (Co) polymer (X-2a) having a melting point in a range of 50 to 140 캜 and a propylene (co) polymer (X-2a) having a melting point in a range of 50 캜 to 140 캜 0.5 to 50% by weight of at least one olefin (co) polymer selected from the ethylene-based (co) polymer (X-2b) (X-1), (X-2), (X-3) and (X-4) consisting of 0 to 50 wt% Surface protection film.

Description

Surface Protective Film {SURFACE PROTECTION FILM}

The present invention relates to a surface protective film used for optical products, building materials, automobile parts, and the like. More specifically, it relates to an adhesive composition which is excellent in adhesion property, particularly stickiness to an adherend and adherence in time, stability in heat resistance, less contamination to an adherend and the like, and also has an appearance such as a fish eye The present invention relates to a surface protective film which is excellent in transparency and does not cause damage to an adherend, and is easy to deliver when rolled out from a roll shape.

The surface protective film is used by adhering to an adherend such as a resin product, a metal product, or a glass product mainly for use in construction materials or for optical applications to prevent scratches or foreign matter from being mixed during transportation, storage and processing thereof have. These surface protective films are generally composed of a surface layer having no tackiness and an adhesive layer for adhering to the adherend. The surface layer is usually formed of a polyolefin such as polyethylene or polypropylene, a polyester such as polyethylene terephthalate, or a vinyl polymer such as polyvinyl chloride.

Background Art [0002] In recent years, development of so-called optical products has been underway for use in liquid crystal displays, plasma displays (PDP), rear projection screens and the like. The surface protective film for protecting these optical products is required not only to have scratches or to incorporate foreign matter but also to have a transparency which enables inspection of the product with the surface protective film attached, And the like are desired.

In optical products, there are many members for which optical characteristics are required, such as polarizing plates, retardation plates, light guide plates and prism plates, and there is a need for protection against these members in which an appropriate adhesive force and a stable adhesive force A film is desired.

On the other hand, in the case where a surface protective film is used for these optical members, when the surface protective film is peeled off, residual adhesive or fish eyes on the surface protective film may cause defects in the optical member, A surface protective film having no fish eye is desired.

In addition, in a surface protective film having a relatively high adhesive strength, it is difficult to deliver the product from a roll-shaped product, so that the release film is adhered to the pressure-sensitive adhesive layer to form a roll, and when the release film is adhered to an adherend, I am using it. If such a process is employed, a large amount of waste is generated, and therefore, a surface protective film that can be easily fed from a roll even without a release film is required.

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

Japanese Patent Application Laid-Open No. 2007-126512 discloses a surface protective film comprising an adhesive layer comprising a styrene-based elastomer as an isobutylene block copolymer and a tackifier resin. However, in the method according to the publication, when the adhesive is adhered to an adherend having a high unevenness, stability with time in adhesion property and adhesive force is insufficient, and further improvement is desired.

Japanese Patent Application Laid-Open No. 2006-116769 Japanese Patent Application Laid-Open No. 2007-126512

The present invention relates to a surface protective film for protecting the surface protective film for protecting at the time of storage, transportation, processing and inspection of an optical product, a building material product or an automobile part, in particular, an adhesive property to an adherend, A surface protective film which is excellent, has less contamination on an adherend or the like, has an excellent appearance such as a fish eye, does not damage an adherend, and is excellent in releasability from a roll.

The present inventors have intensively studied in view of the above problems and found that the above problems can be solved by a surface protective film having a pressure-sensitive adhesive layer made of a specific resin composition, and have completed the present invention.

A surface protective film comprising at least two layers of a surface layer (A) and an adhesive layer (X), wherein the surface layer (A) is made of a polyolefin resin and the adhesive layer (X) has a melting point of less than 50 deg. 0 to 50% by weight of an? -Olefin (co) polymer (X-1) containing as a main component an? -Olefin having 3 or more carbon atoms and a propylene (co) polymer (X- 0.5 to 50% by weight of at least one olefin (co) polymer (X-2) selected from an ethylene-based (co) polymer (X-2b) -3) and 0 to 50% by weight of an oligomer (X-4) having a weight average molecular weight (Mw) in the range of 200 to 9,000 and a softening point in the range of 60 to 160 ° C (X-1), (X-2), (X-3) and (X-4) is 100% by weight) It is about the.

Further, the present invention is a surface protective film characterized in that the styrene-based elastomer (X-3) is a styrene-isobutylene copolymer.

Further, the present invention is a surface protective film which is a multilayer film obtained by extruding at least two layers of the surface layer (A) and the adhesive layer (X) from a T-die.

The surface protective film of the present invention is excellent in adhesion properties, particularly in adhesion properties to high-concavo-convex adherends, stability with time, transparency, releasability and heat resistance, and can be used as a protective film for optical use, The value is very high.

Hereinafter, 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), or at least three layers of a surface layer (A), a base layer (B) and an adhesive layer (X)

Here, when the adhesive layer X is the innermost layer, the surface layer A is located on the outermost layer, and when the film is formed into a roll shape, the surface layer A and the adhesive layer X are in contact with each other.

The surface layer (A) is made of a polyolefin resin.

As the polyolefin resin, a known polyolefin resin such as polypropylene or polyethylene can be mentioned. Examples of the polypropylene include homopolypropylene, random polypropylene and block polypropylene. Examples of the polyethylene include high-pressure processed low-density polyethylene, linear low-density polyethylene and high-density polyethylene. Of these, high pressure low density polyethylene is preferably used from the viewpoint of releasability, and homopolypropylene or block polypropylene is preferably used from the viewpoints of transparency and heat resistance.

The composition for forming the surface layer (A) may contain various additives such as an antistatic agent, a releasing agent, an antioxidant, a lubricant and a nucleating agent, and other additives such as polyolefin resin, A resin modifying agent such as a wax, a polyester, a polyamide, and an elastomer may be added.

The melting point of the? -Olefin (co) polymer (X-1) used in the adhesive layer (X) is less than 50 占 폚 or the melting point is not observed. Here, the melting point is a value measured by a differential scanning calorimeter (DSC). The? -olefin (co) polymer (X-1) is a copolymer containing, as a main component, an? -olefin having 3 or more carbon atoms, such as 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, 1-butene copolymer, 4-methylpentene-1-propylene-1-butene copolymer, and propylene-1-butene copolymer, preferably propylene ethylene-1-butene copolymer.

The melt flow rate (MFR) of the? -olefin (co) polymer (X-1) measured at 230 占 폚 is in the range of 0.1 to 100 g / 10 min, preferably 0.5 to 50 g / 10 min.

The melting point of the propylene (co) polymer (X-2a) is in the range of 50 to 140 占 폚, preferably 55 to 130 占 폚, more preferably 60 to 125 占 폚. The propylene (co) polymer (X-2) is a homopolymer of propylene or a copolymer of propylene and 2 to 10 carbon atoms (excluding propylene) in the presence of a polymerization catalyst, preferably a metallocene catalyst, Propylene homopolymer, propylene-ethylene copolymer, propylene-1-butene copolymer, propylene-ethylene-1-butene copolymer and the like.

As described above, the propylene (co) polymer (X-2a) having a melting point in the range of 50 to 140 占 폚 contains a homopolymer of propylene and propylene as main components and also a copolymer of ethylene and? -Olefin having 4 to 10 carbon atoms There is a copolymer. They preferably have a melt flow rate (MFR) of from 0.1 to 100 g / 10 min, preferably from 0.5 to 50 g / 10 min, as measured at 230 ° C.

The ethylenic (co) polymer (X-2b) is a known ethylenic (co) polymer obtained by homopolymerizing ethylene or copolymerizing ethylene with an? -Olefin having 3 or more carbon atoms in the presence of a polymerization catalyst, preferably a metallocene catalyst. Lt; / RTI > Preferably, it is a copolymer obtained by copolymerizing ethylene and an? -Olefin having 3 to 10 carbon atoms in the presence of a metallocene catalyst. More specific examples include ethylene / propylene copolymer, ethylene / 1-butene copolymer, ethylene / 4-methylpentene-1 copolymer, ethylene / 1-hexene copolymer and ethylene / 1-octene copolymer. On the other hand, metallocene catalysts include half metallocenes and the like, and various other single site catalysts can also be used.

The melting point of the ethylenic (co) polymer (X-2b) measured by a differential scanning calorimeter (DSC) is in the range of 50 占 폚 to 140 占 폚, preferably 60 to 130 占 폚, and more preferably 80 to 125 占 폚 .

The melt flow rate (MFR) of these ethylene (co) polymers measured at 190 캜 is preferably in the range of 0.01 to 20 g / 10 min, preferably 0.5 to 10 g / 10 min.

In the present invention, at least one olefin copolymer (X-2) selected from the propylene (co) polymer (X-2a) and the ethylenic (co) polymer (X-2b) is used.

In the present invention, the olefin copolymer (X-2) is preferably a polymer obtained by using a metallocene catalyst, particularly a polymer obtained by using metallocene having a melting point of 50 to 130 ° C.

On the other hand, metallocene catalysts include half metallocenes and the like, and various other single-site catalysts can also be used.

Examples of the metallocene catalyst include a catalyst comprising a ligand and derivatives of a cyclopentadiene, indene, fluorene, an alkyl substituent thereof, an aryl substituent or the like, and a crosslinked or noncrosslinked metallocene compound composed of a metal such as zirconium or hafnium These are used in the production of these olefin (co) polymers by polymerization together with a co-catalyst system such as aluminoxane.

As the olefin (co) polymer (X-2) used in the present invention, at least one of them is used as needed. Therefore, when two or more propylene (co) polymers (X-2a) are used or when two or more kinds of ethylene (co) polymers are used, the molecular weight distribution (Mw / Mn) But the molecular weight distribution (Mw / Mn) thereof is a polymer having a value of from 1 to 4, preferably from 1.8 to 4, based on polystyrene conversion.

By blending the propylene polymer (X-2a) or ethylene (co) polymer (X-2b) obtained using these metallocene catalysts in the adhesive layer, the adhesive surface of the adhesive layer is not contaminated, There is no nonconformity such as adhesive residue, and the like.

As the styrene-based elastomer (X-3), a known styrene-based elastomer having a polystyrene phase as a hard segment can be used. Specific examples include styrene-butadiene copolymer (SBR), styrene-isoprene-styrene copolymer (SIS), styrene-butadiene-styrene copolymer (SBS), styrene- (Such as styrene, ethylene, butadiene and styrene copolymers (SEBS)), styrene-isobutylene-styrene copolymers such as isoprene-styrene polymers, Triblock copolymer (SIBS), and styrene-isobutylene diblock copolymer (SIB).

In the present invention, the propylene (co) polymer (X-2a) is used in combination and the styrene-isobutylene-styrene triblock copolymer (SIBS) It is preferable to use at least one diblock copolymer selected from styrene / isobutylene diblock copolymer (SIB) together with a block copolymer.

In the case of using a styrene-based elastomer containing these isobutylene components, in the case of using a diblock copolymer such as SIB together with a triblock copolymer such as SIBS, To about 900 parts by weight of a diblock copolymer is used in combination with 20 to 200 parts by weight. As another preferred embodiment of the styrene elastomer (X-3) containing the isobutylene component, the styrene-based elastomer (X-3) may be a diblock copolymer such as SIB alone or a diblock copolymer Is used in an amount of 10 parts by weight or less, particularly 1 to 10 parts by weight, based on 100 parts by weight of the co-polymer.

The weight average molecular weight (hereinafter abbreviated as Mw) of the styrene-based elastomer measured by gel permeation chromatography (GPC) is in the range of 10,000 to 300,000, preferably in the range of 15,000 to 250,000, more preferably in the range of 20,000 to 200,000 . If the Mw is smaller than 10,000 or larger than 300,000, the productivity of the protective film is deteriorated, which is undesirable.

As the oligomer (X-4) used in the adhesive layer (X), it is preferable that the weight average molecular weight (Mw) measured by GPC is in the range of 200 to 9,000 and the softening point measured in JIS K2207 is in the range of 60 to 160 ° C Oligomers. Preferably, the Mw is 300 to 7,000 and the softening point is 70 to 150 ° C, more preferably the Mw is 500 to 5,000, and the softening point is 80 to 140 ° C.

The oligomer (X-4) is not particularly limited as long as it has the above-mentioned molecular weight and softening point, and specific examples thereof include a petroleum resin, a hydrothermal petroleum resin, a styrene resin, a chromene-indene resin, a rosin derivative, . Based resin, preferably a styrene-based resin, a hydrogenated petroleum resin, and more preferably a styrene-based resin. Examples of the styrene-based resin include styrene homopolymer, alpha -methylstyrene homopolymer, styrene / alpha -methylstyrene copolymer, styrene monomer / aliphatic monomer copolymer, alpha -methylstyrene / aliphatic monomer copolymer And styrene-based monomer /? -Methylstyrene / aliphatic monomer copolymer.

The pressure-sensitive adhesive layer (X) of the surface protective film of the present invention preferably comprises 0 to 50% by weight of the? -Olefin (co) polymer (X-1), 0.5 to 50% by weight of the propylene (co) 10 to 98% by weight of the elastomer (X-3), and 0 to 50% by weight of the oligomer (X-4). 0 to 40% by weight of the? -Olefin (co) polymer (X-1), 1 to 40% by weight of the propylene (co) polymer (X-2), 30 to 96% by weight of the styrene- 2 to 30% by weight of the? -Olefin (co) polymer (X-1), 1 to 40% by weight of the oligomer (X- Olefin (co) polymer (X-3) is in the range of from 2 to 30% by weight, the styrene-based elastomer (X-3) is from 50 to 95% by weight and the oligomer 1 to 30% by weight of an oligomer (X-4), 2 to 30% by weight of a propylene (co) polymer (X-2), 68 to 95% by weight of a styrene- (The sum of all (X-1), (X-2), (X-3) and (X-4) is 100% by weight).

In the case of using the ethylene (co) polymer (X-2b) as the olefin (co) polymer (X-2) without using the -olefin (co) polymer (X-2b) in the range of from 0.5 to 50% by weight of the ethylene (co) polymer (X-2b), from 30 to 98% by weight of the styrene elastomer (X- , (X-3) and (X-4) is 100% by weight). More suitably, it is preferable that the content of the ethylene (co) polymer (X-2b) is in the range of 2 to 30 wt%, the styrene elastomer (X-3) is in the range of 50 to 95 wt%, and the oligomer (X-2b), (X-3) and (X-4) is 100% by weight.

A crystalline polyolefin and / or an olefinic elastomer may be added to the adhesive layer (X) in the protective film of the present invention for the purpose of controlling the adhesive force, the adhesive strength with time, and the releasing force.

As the crystalline polyolefin, any known polyolefin having a melting point exceeding 110 캜 (excluding those satisfying all the constituent requirements of the above (X-2)) can be used without limitation, and specific examples thereof include propylene homopolymer, Butene copolymer, a 1-butene-ethylene copolymer, a 1-butene-propylene copolymer, a 4-methylpentene-1 homopolymer, a 4-methylpentene- 1-propene copolymer, 4-methylpentene-1-butene copolymer, 4-methylpentene-1propylene-1-butene copolymer, propylene-1-butene copolymer, ethylene homopolymer, Olefin copolymers, ethylene-vinyl acetate copolymers, ethylene-methacrylic acid copolymers, and ethylene-methyl methacrylate copolymers.

As the olefinic elastomer, an? -Olefin polymer or copolymer having a melting point of 110 ° C or lower, preferably a melting point of 100 ° C or lower, more preferably a melting point of 80 ° C or lower or a melting point of 2 to 20 carbon atoms, And an unsaturated carboxylic acid or an unsaturated carboxylic acid ester (provided that the polymer satisfying all the constituent requirements of the above (X-4) is excluded). Specific examples include ethylene / 1-butene copolymer, ethylene 1-hexene copolymer, ethylene 4-methylpentene-1 copolymer, ethylene 1-octene copolymer, propylene homopolymer, Butene copolymer, a 1-butene-ethylene copolymer, a 1-butene-propylene copolymer, a 4-methylpentene-1 homopolymer, a 4-methyl Pentene-1-propene copolymer, 4-methylpentene-1-butene copolymer, 4-methylpentene-1propylene-1-butene copolymer, propylene-1-butene copolymer, ethylene- , Ethylene-methacrylic acid copolymer, ethylene-methyl methacrylate copolymer, and the like.

(X-1), (X-2), (X-3) and (X-3) are used as the content of the crystalline polyolefin and / or olefinic elastomer as one component of the adhesive layer (X) 0.5 to 50 parts by weight, preferably 0.5 to 40 parts by weight, more preferably 0.5 to 30 parts by weight, based on 100 parts by weight of the composition comprising (A) and (X-4)

The addition of the crystalline polyolefin and / or the olefinic elastomer enables the desired adhesive force to be exhibited, and the adhesive property suitable for various adherends can be exhibited.

In the case of using the ethylene (co) polymer (X-2b) as the olefin (co) polymer (X-2) without using the -olefin (co) polymer When the crystalline polyolefin and / or the olefinic elastomer is used as one component of the adhesive layer (X) of the protective film of the present invention, the content of the styrene-based elastomer (X-3), the ethylene- Is preferably 0.5 to 100 parts by weight, preferably 1 to 50 parts by weight, more preferably 2 to 40 parts by weight based on 100 parts by weight of the composition comprising the oligomer (X-2b) and the oligomer (X-4)

The addition of the crystalline polyolefin and / or the olefinic elastomer enables the desired adhesive force to be exhibited, and the adhesive property suitable for various adherends can be exhibited.

By the composition comprising (X-1), (X-2), (X-3) and (X-4) and optionally a crystalline polyolefin and / or olefinic elastomer added, The pressure-sensitive adhesive layer (X) in the protective film can be formed. In the present invention, various additives such as resin modifiers such as acid-modified polyolefins, polyesters and polyamides, antistatic agents, nucleating agents and antioxidants may be added within the range not impairing the properties of the present invention There may be.

In the present invention, at least one base layer (B) can be provided between the surface layer (A) and the adhesive layer (X). For the purpose of controlling the mechanical strength and transparency of the film, and when the adhesion between the surface layer (A) and the adhesive layer (X) is insufficient, a polyolefin resin, an adhesive resin or an adhesive may be used as the intermediate layer.

The base layer is not particularly limited, but a crystalline polyolefin such as polypropylene or polyethylene having a melting point of 100 占 폚 or more, polyester, polyamide, polyolefin elastomer, or the like can be used. When the base layer is used as an adhesive layer, a modified polyolefin, a polyolefin elastomer, a styrene-based elastomer, a polyester elastomer, or the like is used. Among these, from the viewpoints of productivity and transparency, it is preferable to use a polypropylene or polyolefin elastomer as an intermediate layer.

The composition comprising the above-mentioned (X-1), (X-2), (X-3) and (X-4) and optionally the crystalline polyolefin and / or olefinic elastomer, and if necessary, the resin modifier or additive , The surface layer (A) and, if necessary, the base layer (B), to form the surface protective film of the present invention.

The method for laminating the surface layer (A), the pressure-sensitive adhesive layer (X) and the base layer (B) when necessary is not particularly limited, but the surface layer film obtained by T- Extrusion coating, or a method in which the base layer and the adhesive layer are independently formed into films, and then the respective films are laminated by dry lamination. From the viewpoint of productivity, however, Co-extrusion molding in which each component of the surface layer, the base layer, and the adhesive layer is provided to a multi-layer extruder and molded is preferable.

The thickness of the surface layer (A) in the surface protective film of the present invention is 0.1 to 100 占 퐉, preferably 0.3 to 50 占 퐉, more preferably 0.5 to 30 占 퐉, and still more preferably 1 to 20 占 퐉. The thickness of the adhesive layer X is 0.1 to 50 占 퐉, preferably 0.3 to 40 占 퐉, and more preferably 0.5 to 30 占 퐉.

The thickness of the surface protective film of the present invention is 1 to 300 占 퐉, preferably 2 to 200 占 퐉, more preferably 3 to 100 占 퐉.

By using the surface layer (A), the adhesive layer (X) and, if necessary, the base layer (B) of the preferred form, the adhesive property, particularly excellent adhesion to the adherend having high unevenness such as a prism sheet, A surface protective film excellent in transparency can be obtained and can be suitably used particularly for use as a construction material or for optical use.

Example

Hereinafter, the present invention will be described in detail by way of examples, but the present invention is not limited to these examples.

[Evaluation method]

Adhesion (acrylic plate)

The acrylic plate was cut into a width of 50 mm and a length of 125 mm, and the test plate was attached using a 2-kg rubber roller. Subsequently, the peeling force at the time of peeling (180 degrees peeling) at a rate of 300 mm / min is measured, and the peeling force per 50 mm peaks is taken as the peeling force (N / 50 mm).

adhesiveness( Prism plate )

A peeling force is measured when a protective film is attached to a commercially available prism sheet and peeled off (180 degrees peeled off) at a rate of 300 mm / min. The peel force per 50 mm peel is taken as an adhesive force (N / 50 mm).

Melt Flow Rate ( MFR )

Measured according to ASTM D1238 under a load of 2.16 kg and a temperature of 230 占 폚.

Adhesive  Residual Contamination )

The measurement of the adhesive residue was made by attaching a test piece to the surface of an acrylic plate having a width of 50 mm and a length of 100 mm such that the bubble enters the adhesive film. The test piece was held at 50 占 폚 for one week and then allowed to stand at 23 占 폚 for 1 hour. Then, the adhesive film was peeled off from the acrylic plate, and the state of the acrylic plate was visually observed.

The case where the adhesive residue or the contaminant was not present on the acrylic plate was evaluated as " ", and the case where it was evaluated as " x ".

Release force ( Runnability )

Using a roll-shaped sample, the peeling force (N / 25 mm) at the time of peeling from the roll at a speed of 300 mm / min is measured to obtain a releasing force.

 [Example 1A]

The following resin compositions were supplied to the three-kind three-layer three-layer T-die molding machine having a die width of 500 mm having a single-screw extruder of 40 mm in diameter for the surface layer, the base layer and the adhesive layer, A surface protective film having a layer thickness of 10 mu m, a base layer thickness of 30 mu m, and a total thickness of 50 mu m was obtained. Table 1 shows the evaluation results of the obtained film.

Surface layer:

LD-1: high pressure low density polyethylene

(Density: 0.920 g / cm ³ , MFR (190 ° C): 6 g / 10 min)

Base layer:

PP-1: homopolypropylene

(Melting point 160 캜, MFR (230 캜) 7 g / 10 min)

EL-1: Ethylene / 1-butene copolymer

(Trade name: TAFMA, trade name: A-4085S, MFR = 3.6 g / 10 min, manufactured by Mitsui Chemicals, Inc.)

Adhesive layer:

PEBR: propylene / ethylene / 1-butene copolymer

(Ethylene content 13 mol%, butene content 19 mol%, melting point not observed, MFR = 7 g / 10 min)

SIBS: styrene-isobutylene-styrene triblock copolymer

(Trade name: Shibusuta, trade name: 062T, MFR = 8.0 g / 10 min, manufactured by Kaneka Corporation)

SIB: styrene-isobutylene diblock copolymer

(Trade name: Shibusuta, trade name: 042D, MFR = 8 g / 10 min, manufactured by Kaneka Corporation)

OL-1: styrene-based monomer / aliphatic monomer copolymer (oligomer)

(Trade name: FTR, trade name: FTR6125, Mw = 1950, softening point 125 캜, manufactured by Mitsui Chemicals, Inc.)

OL-2: Water-based petroleum resin (oligomer)

(Trade name: Arcon, trade name: P-125, softening point 125 캜, Mw = 1200, manufactured by Arakawa Chemical Industries, Ltd.)

PP-A: Propylene / ethylene copolymer

(Mw / Mn = 4.0, melting point = 138 占 폚, MFR = 7 g / 10 min)

MP-1: Propylene / ethylene copolymer (prepared using a metallocene catalyst)

(Mw / Mn = 2.1, melting point = 115 占 폚, MFR = 7 g / 10 min)

MP-2: Propylene / 1-butene copolymer (prepared using a metallocene catalyst)

(Molecular weight distribution (Mw / Mn) = 2.0, melting point 70 占 폚, MFR = 7 g / 10 min)

PP-2: homopolypropylene

(Trade name: F107BV, melting point = 160 DEG C, MFR = 7 g / 10 min, manufactured by Prime Polymer Co., Ltd.)

[Examples 2A, 3A, 5A, 6A, 9A, Comparative Examples 1A to 4A and Reference Examples 4A, 7A, 8A]

A surface protective film was obtained in the same manner as in Example 1A, except that the resin composition of the various layers was changed to the resin composition shown in Table 1. Table 1 shows the evaluation results of the obtained film.

The protective film according to the present invention is excellent in adhesion to prills such as a prism and stability with time of adhesion.

[Referential Example 1B]

The following resin compositions were supplied to the three-kind three-layer three-layer T-die molding machine having a die width of 500 mm, each having a 40 mm phi single screw extruder for the surface layer, the base layer and the adhesive layer and each having the surface layer thickness of 10 m, 10 mu m, a base layer thickness of 30 mu m, and a total thickness of 50 mu m. The evaluation results of the obtained films are shown in Table 2.

However, the composition of the surface layer and base layer was the same as in Example 1A.

Adhesive layer:

SEBS: styrene-butadiene-styrene block copolymer hydride

(Trade name: Tarp Tech, trade name: H1221, MFR = 8.0 g / 10 min, manufactured by Asahi Chemical Industry Co., Ltd.)

OL-1: styrene-based monomer / aliphatic monomer copolymer (oligomer)

(Trade name: FTR, trade name: FTR6125, Mw = 1950, softening point 125 캜, manufactured by Mitsui Chemicals, Inc.)

OL-2: Water-based petroleum resin (oligomer)

(Trade name: Arcon, trade name: P-125, softening point 125 캜, Mw = 1200, manufactured by Arakawa Chemical Industries, Ltd.)

ME-1: Ethylene / 1-hexene copolymer (manufactured by metallocene catalyst)

(Molecular weight distribution (Mw / Mn) 2.1, melting point = 115 ℃, MFR (190 ℃ ) = 3.6 g / 10 min, density 0.915 g / cm ³⁾

PP-2: homopolypropylene

(Trade name: F107BV, melting point = 160 DEG C, MFR = 7 g / 10 min, manufactured by Prime Polymer Co., Ltd.)

[Reference Examples 2B, 3B and Comparative Examples 1B and 2B]

A surface protective film was obtained in the same manner as in Reference Example 1B except that the resin composition of the various layers was changed to the resin composition shown in Table 2. [ The evaluation results of the obtained films are shown in Table 2.

Claims (3)

A surface protective film comprising at least two layers of a surface layer (A) and an adhesive layer (X)
Wherein the surface layer (A) is made of a polyolefin resin,
The adhesive layer (X)
Propylene homopolymer, a propylene / ethylene copolymer, a propylene / ethylene / 1-butene copolymer, a 1-butene homopolymer, a 1-butene · ethylene copolymer, a 1-butene · propylene copolymer, , 4-methylpentene-1-propene copolymer, 4-methylpentene-1-butene copolymer, 4-methylpentene-1propylene-1-butene copolymer and propylene-1-butene copolymer 2 to 15% by weight of an? -Olefin homopolymer or? -Olefin copolymer (X-1) having a melting point of less than 50 ° C or a melting point not observed,
A propylene homopolymer or propylene copolymer (X-2a) having a melting point in a range of 50 to 140 占 폚 and an ethylene homopolymer or an ethylene copolymer (X-2b) having a melting point in a range of 50 占 폚 to 140 占 폚 2 to 30% by weight of a homopolymer or copolymer (X-2) of at least one olefin selected,
68 to 95% by weight of a styrene-based elastomer (X-3), and
1 to 30% by weight of an oligomer (X-4) having a weight average molecular weight (Mw) in the range of 200 to 9,000 and a softening point in the range of 60 to 160 DEG C,
(X-1), (X-2), (X-3) and (X-4) is 100% by weight). The method according to claim 1,
A surface protective film characterized in that the styrene-based elastomer (X-3) is a styrene-isobutylene copolymer. 3. The method according to claim 1 or 2,
A surface protective film which 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.