JP4929213B2 - Surface protection film - Google Patents

Description

  The present invention relates to a surface protective film, and more specifically, to protect a surface of a building member such as a synthetic resin plate, a decorative plate, a metal plate, and a glass plate, and to protect a surface of a constituent member of a liquid crystal display such as a polarizing plate and a retardation plate. The present invention relates to a film for protecting a surface which is preferably used as an application.

  Surface protection films are affixed to building materials such as synthetic resin plates and liquid crystal display parts of optical equipment members from the viewpoint of preventing scratches and dirt on the surface during processing, transportation and transportation, and after processing or transportation and transportation. It is common to peel off and use the surface protection film which concerns later.

  Conventionally, as the surface protective film, there is a surface protective film mainly composed of an ethylene-based resin. For example, a surface protective film made of an ethylene-based resin that is polymerized from a metallocene catalyst, has a narrow composition distribution and molecular weight distribution, and does not have fish eye is described (for example, see Patent Document 1). Further, a polyethylene composed of 50 to 90% by weight of a specific low density polyethylene and 10 to 50% by weight of a specific high density polyethylene having a weight average molecular weight / number average molecular weight ratio of 9 to 15, and an ethylene-unsaturated ester A laminated film obtained by coextruding a pressure-sensitive adhesive layer made of a copolymer is described (for example, see Patent Document 2).

However, in the surface protective film described in the above patent document, since polyethylene is the main component, retention occurs inside the molding machine extruder during film formation, gelation occurs due to deterioration of the ethylene component, Since the fish eye is generated, when the product is attached to the object to be protected and stacked and stored as it is, the object to be protected is dented due to the presence of the fish eye. Therefore, for example, even if an attempt is made to use the laminated film as a polarizing plate or a retardation plate used as a liquid crystal display material, there is a problem that the image is distorted due to the dents and cannot be applied.
In addition, in view of problems of heat resistance, scratch resistance, and rigidity of polyethylene, and having improved the point defects of the metal thin film layer due to the influence of chlorine ions, it is made of polypropylene having a chlorine content of 5 ppm by weight or less. A surface protective film containing a characteristic propylene-based resin as a main component has also been proposed (see, for example, Patent Document 3). However, even in the propylene-based resin described in the patent document, gelation like polyethylene does not occur, but the molecular weight distribution is wide, that is, low molecular weight having a low molecular weight and high molecular weight having a high molecular weight are mixed. Therefore, when the high molecular weight component is formed into a film, an unmelted fine lump becomes a fish eye and exists in the film, resulting in a dent in the protected object.

Further, both ethylene-based resins and propylene-based resins have a crystallinity distribution, but there is a problem that if the crystallinity distribution is wide and there are many low crystal components, the object to be protected is contaminated. In addition, in the process of producing the polymer, sticking of the low crystal component causes polymer adhesion in a polymerization tank or the like, resulting in deterioration of the polymer due to stagnation, and as a result, fish eyes derived from polymer degradation products exist in the film. As a result, the object to be protected is dented, and there is a problem that it cannot be applied as a surface protective film. In addition, if the crystallinity distribution is wide, the compatibility between the low crystallinity component and the high crystallinity component becomes non-uniform, and the high crystallinity component tends to exist as fish eyes in the form of a fine unmelted mass. Similarly, there is a problem that it cannot be applied as a surface protective film.
JP-A-9-111208 JP 54-133578 A JP 2006-282761 A

  In view of the problems of the prior art described above, the present invention has a very small fish eye, and preferably a synthetic resin plate, a decorative plate, a metal plate, a glass plate, etc., with improved peel force control and feeding performance. An object of the present invention is to provide a propylene-based resin surface protective film suitable as a surface protective film for building members and as a surface protective film for liquid crystal display components such as polarizing plates and retardation plates.

  As a result of repeating various studies to solve the above problems, the present inventor has obtained a specific melt flow rate, a melting peak temperature by a differential thermal scanning calorimeter, a weight average molecular weight and a number average molecular weight determined by gel permeation chromatography. By using a polypropylene-based resin having a soluble content of 40 ° C. or less measured by a temperature rising elution fractionation method, a surface protective film with less fish eyes can be obtained, and a specific ethylene · The present invention has been completed by finding that a film for surface protection with improved peel force control and feeding performance can be obtained by combining with an α-olefin copolymer.

That is, according to the first invention of the present invention, in the surface protective film in which the pressure-sensitive adhesive layer is formed on one surface of the base material layer made of propylene-based resin,
The pressure-sensitive adhesive layer is polymerized using a metallocene catalyst, the density is 0.860 to 0.918 g / cm ^3, and the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is 3. A layer mainly composed of an ethylene / α-olefin copolymer of 5 or less,
The propylene-based resin is a propylene homopolymer or a propylene / α-olefin random copolymer polymerized using a metallocene catalyst and having the following properties (A1) to (A4): A protective film is provided.
(A1) Melt flow rate (MFR: 230 ° C., 21.18 N load) is 1 to 50 g / 10 minutes (A2) Melting peak temperature (Tmp) by differential thermal scanning calorimeter (DSC) is 120 to 170 ° C.
(A3) The ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) determined by gel permeation chromatography (GPC) is 1.5 to 3.5.
(A4) Soluble content (S ₄₀ ) of 40 ° C. or less measured by temperature rising elution fractionation (TREF) method is 10% by weight or less

According to a second aspect of the present invention, there is provided a surface protecting film according to the first aspect , wherein the propylene-based resin further has the following property (A5).
(A5) The range (T ₁₀₀ -T ₂₀ ) of the temperature (T ₁₀₀ ) at the end of elution by 100 wt% from the temperature (T ₂₀ ) at the elution of 20 wt% by the temperature rising elution fractionation (TREF) method is 30 ° C. Less than.

According to the third invention of the present invention, in the first or second invention, the adhesive layer is formed on one surface of the base material layer, and the release treatment layer is formed on the other surface. A surface protective film is provided.

Further, according to the fourth invention of the present invention, in any one of the first to third inventions, it is used for surface protection of building members such as a synthetic resin plate, a decorative plate, a metal plate, and a glass plate. A surface protective film is provided.

According to a fifth aspect of the present invention, in any one of the first to third aspects, the surface is used for surface protection of liquid crystal display components such as a polarizing plate and a retardation plate. A protective film is provided.

  The film for surface protection of the present invention is made of a specific propylene resin, because the crystallinity distribution of the resin is narrow, the amount of low crystalline components eluted is small, the molecular weight distribution is narrow, and the high molecular weight component is small. There is very little unmelted fish eye during film forming. For this reason, even if a surface protection film is affixed on a to-be-protected object and stored in a stacked manner, the to-be-protected object does not dent. Moreover, the film for surface protection of this invention is excellent in blocking property without using an antiblocking agent, and is excellent in transparency. Furthermore, when a specific ethylene / α-olefin copolymer polymerized using a metallocene catalyst is used as the pressure-sensitive adhesive layer, it adheres firmly when at least one of the base material layer and the pressure-sensitive adhesive layer is laminated in a molten state. And it can be set as the film for surface protection which has the characteristic that it peels off smoothly when a roll is unwound from the roll winding state which both an adhesion layer and a base material layer contact in a solid state.

  The present invention is a surface protective film having a pressure-sensitive adhesive layer formed on one surface of a base material layer and a base material layer, and further, if necessary, a pressure-sensitive adhesive layer and a release treatment layer on the other surface, The base material layer is polymerized using a metallocene catalyst, and a propylene homopolymer or propylene / α-olefin random copolymer having characteristics (A1) to (A4) and, if necessary, further characteristics (A5) It is a film for surface protection made of a propylene-based resin which is a coalescence. Hereinafter, the component of each layer of the film for surface protection of this invention and the manufacturing method of the film for surface protection are demonstrated in detail.

1. Base material layer The base material layer in the film for surface protection of the present invention is composed of a propylene-based resin. As the propylene-based resin, a propylene homopolymer or a propylene / α-olefin random copolymer of a copolymer of propylene and an α-olefin can be used. Here, examples of the α-olefin as the copolymer component include ethylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene and the like.

  Specific examples of the propylene / α-olefin random copolymer used in the present invention include propylene / ethylene random copolymer, propylene / 1-butene random copolymer, propylene / 1-hexene random copolymer, propylene / ethylene. -1-butene copolymer etc. are mentioned. Preferably, a propylene / ethylene random copolymer, a propylene / 1-butene random copolymer, a propylene / ethylene / 1-butene copolymer, and the like are used. More preferred is a propylene / ethylene random copolymer.

  The propylene-based resin used in the present invention has the following characteristics (A1) to (A4), and further has characteristics (A5) as necessary.

(A1) Melt flow rate The melt flow rate (MFR) of the propylene-based resin used in the present invention is 1 to 50 g / 10 minutes, preferably 2 to 30 g / 10 minutes, and more preferably 5 to 20 g / 10. Minutes, most preferably 7-15 g / 10 min.
If the MFR is less than 1 g / 10 minutes, the extrusion characteristics are deteriorated and the productivity is lowered, which is not preferable, and if the MFR exceeds 50 g / 10 minutes, the thickness accuracy at the time of film forming tends to be deteriorated.
MFR can be adjusted by the amount of hydrogen during polymerization. For example, increasing the amount of hydrogen increases the MFR.
In addition, the melt flow rate (MFR: unit g / 10min) employ | adopted in this invention is a value measured by 230 degreeC and a load of 21.18N load based on JISK-7210-1995.

(A2) Melting peak temperature The melting peak temperature (Tmp) of the propylene-based resin used in the present invention is 120 to 170 ° C, preferably 120 to 165 ° C, more preferably 120 to 160 ° C, and most preferably. Is 120 ° C to 150 ° C.
When the melting peak temperature is less than 120 ° C., the heat resistance is inferior, and the surface protection film is likely to be deformed during the processing step of applying heat to the surface protection film on the object to be protected. When the melting peak temperature is higher than 170 ° C., the impact strength is inferior, and there is a possibility that tearing may occur when the surface protection film is attached to an object to be protected.
The melting peak temperature (Tmp) can be adjusted by the amount of α-olefin used. For example, as the amount of α-olefin increases, the melting peak temperature (Tmp) decreases.
In addition, the melting peak temperature (Tmp: unit ° C) employed in the present invention is a differential scanning calorimeter (DSC), a sample amount of 5.0 mg is taken and held at 200 ° C for 5 minutes, and then 40 ° C. This is a value for measuring the melting peak temperature (Tmp) when crystallization is performed at a temperature lowering speed of 10 ° C./min until further melting at a temperature rising speed of 10 ° C./min.

(A3) Ratio of weight average molecular weight (Mw) and number average molecular weight (Mn) Ratio (Mw / Mn) of weight average molecular weight (Mw) and number average molecular weight (Mn) of the propylene-based resin used in the present invention is It is 1.5-3.5, Preferably it is 1.7-3.2, More preferably, it is 2.0-3.0, Most preferably, it is 2.3-2.8. When (Mw / Mn) is less than 1.5, the viscosity of the molten resin becomes high, the melt fluidity becomes poor, and extrusion molding becomes difficult. On the other hand, when (Mw / Mn) exceeds 3.5, the abundance ratio of molecules having a low molecular weight and molecules having a high molecular weight becomes high, and the high molecular weight component becomes an unmelted fish eye at the time of film formation and is stuck on a protected object. After that, if the products are stacked and stored as they are, the objects to be protected will be dented.
(Mw / Mn) can be adjusted by changing the polymerization conditions (polymerization temperature, polymerization pressure) during production and the type of catalyst used.

The weight average molecular weight (Mw) / number average molecular weight (Mn) used in the present invention is measured by gel permeation chromatography (GPC). The measurement conditions are as follows.
Apparatus: GPC 150C type manufactured by Waters Inc. Detector: 1A infrared spectrophotometer manufactured by MIRAN (measurement wavelength: 3.42 μm)
Column: Showa Denko Co., Ltd. AD806M / S 3 (column calibration is Tosoh monodisperse polystyrene (A500, A2500, F1, F2, F4, F10, F20, F40, F288 each 0.5 mg / ml solution) The logarithm of the elution volume and molecular weight was approximated by a quadratic equation, and the molecular weight of the sample was converted to polypropylene using the viscosity equation of polystyrene and polypropylene, where the coefficient of the viscosity equation of polystyrene was α = 0. .723, log K = −3.967, and polypropylene has α = 0.707 and log K = −3.616.)
Measurement temperature: 140 ° C
Concentration: 20 mg / 10 mL
Injection volume: 0.2ml
Solvent: Orthodichlorobenzene Flow rate: 1.0 ml / min Viscosity formula: log [η] = log K + α × log M

(A4) Soluble content of 40 ° C. or less by temperature rising elution fractionation (TREF) method (S ₄₀ )
The soluble content (S ₄₀ ) of 40 ° C. or less measured by the temperature rising elution fractionation (TREF) method of the propylene resin used in the present invention is 10% by weight or less, preferably 8% by weight or less, more preferably Is 6% by weight or less, and most preferably 4% by weight or less.
When the soluble content (S ₄₀ ) of 40 ° C. or less measured by the temperature rising elution fractionation (TREF) method is more than 10% by weight, there is a problem that the protected material is contaminated by the low crystalline component sticky component. In addition, in the process of producing the polymer, sticking of the low crystal component causes polymer adhesion in a polymerization tank or the like, resulting in deterioration of the polymer due to stagnation, and as a result, fish eyes derived from polymer degradation products exist in the film. End up.
The soluble content (S ₄₀ ) of 40 ° C. or lower can be adjusted by changing the polymerization conditions (polymerization temperature, polymerization pressure) during production, the type and amount of the catalyst and α-olefin used, and the composition.

(A5) by Atsushi Nobori elution fractionation _(T 100 _{-T 20)}
Width (T ₁₀₀ -T) of temperature (T ₁₀₀ ) when 100 wt% elution is completed from temperature (T ₂₀ ) when 20 wt% is eluted by the temperature rising elution fractionation (TREF) method of the propylene resin used in the present invention. ₂₀ ) is preferably 30 ° C. or lower, more preferably 25 ° C. or lower, further preferably 20 ° C. or lower, and most preferably 15 ° C. or lower. When (T ₁₀₀ -T ₂₀ ) exceeds 30 ° C., a component having high crystallinity and a component having low crystallinity are simultaneously present in the propylene-based resin, and the size and quality of the crystal component are not uniform. As a result, there is unevenness in the viscosity of the molten resin, and an unmelted fine lump becomes a fish eye and exists in the film.
Using a Atsushi Nobori elution fractionation (T _{100 -T 20),} the polymerization conditions at the time of production (polymerization temperature, polymerization pressure), the type of catalyst and α- olefin used and the amount can be adjusted by changing the composition.

The temperature rising elution fractionation (TREF) method employed in the present invention is the method shown below.
That is, a sample is dissolved in orthodichlorobenzene at 140 ° C. to obtain a solution. This is introduced into a 140 ° C. TREF column, cooled to 100 ° C. at a rate of 8 ° C./min, subsequently cooled to 40 ° C. at a rate of 4 ° C./min, and held for 10 minutes. Thereafter, orthodichlorobenzene as a solvent is caused to flow through the column at a flow rate of 1 mL / min, and components dissolved in 40 ° C orthodichlorobenzene are eluted in the TREF column for 10 minutes, and then the heating rate is 100 ° C / hour. The column is linearly heated to 140 ° C. to obtain an elution curve.
From the elution curve obtained according to the above conditions, the ratio (% by weight) to the total amount of components eluted at 40 ° C. is calculated. Moreover, to calculate the width of the temperature at which eluted 20% by weight temperature upon 100 wt% elution-ending from _{(T 20) (T 100)} (T 100 -T 20). Conditions such as a column to be used, a solvent, and a temperature are as follows.
Column size: 4.3mmφ × 150mm
Column packing material: 100 μm surface inert treatment glass beads Solvent: Orthodichlorobenzene Sample concentration: 5 mg / mL
Sample injection volume: 0.2 mL
Solvent flow rate: 1 mL / min Detector: Fixed wavelength infrared detector MIOX 1A manufactured by FOXBORO
Measurement wavelength: 3.42 μm

Such a propylene resin is required to be polymerized using a metallocene catalyst. A propylene homopolymer or propylene / α-olefin random copolymer polymerized with a metallocene catalyst has a narrow crystallinity distribution and molecular weight distribution, and therefore, as described above, has few components that become fish eye.
On the other hand, when a propylene homopolymer polymerized with a catalyst other than a metallocene catalyst such as a so-called Ziegler-Natta catalyst containing magnesium, titanium, halogen, and an electron donor as an essential component, or a propylene / α-olefin random copolymer is used, Wide molecular weight distribution and high content of high molecular weight component, wide crystal distribution, many low crystal components, and non-uniform crystallinity distribution, resulting in unmelted fine lump in the film And it becomes easy to exist as fish eyes.

  The metallocene catalyst used in the present invention is (i) a group 4 transition metal compound containing a ligand having a cyclopentadienyl skeleton (so-called metallocene compound) and (ii) a metallocene compound. It is a catalyst comprising a cocatalyst that can be activated to a stable ionic state and, if necessary, (iii) an organoaluminum compound, and any known catalyst can be used. The metallocene compound is preferably a bridged metallocene compound capable of stereoregular polymerization of propylene, and more preferably a bridged metallocene compound capable of isoregular polymerization of propylene. Each component will be described.

  Examples of (i) metallocene compounds include JP-A-60-35007, JP-A-63-130314, JP-A-63-295607, JP-A-1-275609, JP-A-2-41303, and JP-A-2-41303. JP-A-2-131488, JP-A-2-76887, JP-A-3-163888, JP-A-4-30087, JP-A-4-21694, JP-A-5-43616, JP-A-5-209913, JP-A-6 No. 239914, JP-A-7-504934, and JP-A-8-85708.

More specifically, methylene bis (2-methylindenyl) zirconium dichloride, ethylenebis (2-methylindenyl) zirconium dichloride, ethylene 1,2- (4-phenylindenyl) (2-methyl-4-phenyl) -4H-azulenyl) zirconium dichloride, isopropylidene (cyclopentadienyl) (fluorenyl) zirconium dichloride, isopropylidene (4-methylcyclopentadienyl) (3-t-butylindenyl) zirconium dichloride, dimethylsilylene (2- Methyl-4-t-butyl-cyclopentadienyl) (3′-t-butyl-5′-methyl-cyclopentadienyl) zirconium dichloride, dimethylsilylenebis (indenyl) zirconium dichloride, dimethylsilylenebis (4,5 , , 7-tetrahydroindenyl) zirconium dichloride, dimethylsilylenebis [1- (2-methyl-4-phenylindenyl)] zirconium dichloride, dimethylsilylenebis [1- (2-ethyl-4-phenylindenyl)] zirconium Dichloride, dimethylsilylenebis [4- (1-phenyl-3-methylindenyl)] zirconium dichloride, dimethylsilylene (fluorenyl) t-butylamidozirconium dichloride, methylphenylsilylenebis [1- (2-methyl-4, ( 1-naphthyl) -indenyl)] zirconium dichloride, dimethylsilylenebis [1- (2-methyl-4,5-benzoindenyl)] zirconium dichloride, dimethylsilylenebis [1- (2-methyl-4-phenyl-4H) -Azulenyl) ] Zirconium dichloride, dimethylsilylenebis [1- (2-ethyl-4- (4-chlorophenyl) -4H-azurenyl)] zirconium dichloride, dimethylsilylenebis [1- (2-ethyl-4-naphthyl-4H-azurenyl)] Zirconium dichloride, diphenylsilylene bis [1- (2-methyl-4- (4-chlorophenyl) -4H-azulenyl)] zirconium dichloride, dimethylsilylene bis [1- (2-ethyl-4- (3-fluorobiphenylyl) ) -4H-azurenyl)] zirconium dichloride, dimethylgermylenebis [1- (2-ethyl-4- (4-chlorophenyl) -4H-azurenyl)] zirconium dichloride, dimethylgermylenebis [1- (2-ethyl-) 4-phenylindenyl)] zirconium Zirconium compounds such as chloride can be exemplified. In the above, compounds in which zirconium is replaced with titanium or hafnium can be used in the same manner. In some cases, a mixture of a zirconium compound and a hafnium compound can be used. Further, the chloride can be replaced with other halogen compounds, hydrocarbon groups such as methyl, isobutyl and benzyl, amide groups such as dimethylamide and diethylamide, alkoxide groups such as methoxy group and phenoxy group, hydride groups and the like.
Among these, a metallocene compound in which an indenyl group or an azulenyl group is crosslinked with silicon or a germyl group is preferable. In particular, a polymer obtained by a catalyst in which a metallocene compound having an azulenyl group and a clay mineral are combined has excellent balance of film forming property and low fish eye.

The metallocene compound may be used by being supported on an inorganic or organic compound carrier. The carrier is preferably an inorganic or organic porous compound. Specifically, ion-exchange layered silicate, zeolite, SiO ₂ , Al ₂ O ₃ , silica alumina, MgO, ZrO ₂ , TiO ₂ , B Examples include inorganic compounds such as ₂ O ₃ , CaO, ZnO, BaO, and ThO ₂ , organic compounds composed of porous polyolefin, styrene / divinylbenzene copolymer, olefin / acrylic acid copolymer, and the like, or a mixture thereof. It is done.

  (Ii) As a co-catalyst that can be activated to a stable ionic state by reacting with a metallocene compound, an organoaluminum oxy compound (for example, an aluminoxane compound), an ion-exchange layered silicate, a Lewis acid, a boron-containing compound, an ionic compound And fluorine-containing organic compounds.

  (Iii) Examples of organoaluminum compounds include trialkylaluminum such as triethylaluminum, triisopropylaluminum, triisobutylaluminum, dialkylaluminum halide, alkylaluminum sesquihalide, alkylaluminum dihalide, alkylaluminum hydride, organoaluminum alkoxide. Can be mentioned.

Examples of the polymerization method include a slurry method using an inert solvent in the presence of the catalyst, a solution method, a gas phase method substantially using no solvent, or a bulk polymerization method using a polymerization monomer as a solvent. . As a method for obtaining propylene used in the present invention, for example, a desired polymer can be obtained by adjusting the polymerization temperature and the comonomer amount and appropriately controlling the molecular weight and crystallinity distribution.
Such polypropylene can be appropriately selected from those commercially available as metallocene polypropylene. Examples of commercially available products include “Wintech” manufactured by Nippon Polypro.
The propylene resin of the present invention may be composed of one type or a combination of two or more types as long as the above properties are satisfied.

2. Pressure-sensitive adhesive layer In the surface protective film of the present invention, a pressure-sensitive adhesive layer is formed on one surface of the base material layer made of the propylene-based resin.
The pressure-sensitive adhesive is not particularly limited as long as it is a known one. For example, a rubber-based pressure-sensitive adhesive, an acrylic pressure-sensitive adhesive, a soft polypropylene resin, an ethylene / vinyl acetate copolymer, an ethylene polymer (ethylene / acrylic copolymer) Polymers, other than ethylene / vinyl acetate copolymer) are preferably used. The pressure-sensitive adhesive is not limited to its composition. Below, each adhesive is demonstrated in detail.

(1) Rubber-based pressure-sensitive adhesives As rubber-based pressure-sensitive adhesives, for example, those mainly composed of natural rubber and synthetic rubber are used. In particular, from the viewpoint of pollution-free by hot melt coating, ABA type or AB type block copolymer (A means a styrene polymer block, B means a butadiene polymer block, an isoprene polymer block, or a polymer block obtained by hydrogenating these), for example, styrene-isoprene Copolymer (SI), styrene-isoprene-styrene copolymer (SIS), styrene-butadiene copolymer (SB), styrene-butadiene-styrene copolymer (SBS), styrene-ethylene-butadiene-styrene copolymer Those mainly composed of coalescence (SEBS) or the like are preferable. The composition of the rubber-based pressure-sensitive adhesive is not particularly limited as long as the effects of the present invention are not impaired, but a styrene content of 5 % by weight or more, particularly about 10 to 30% by weight is preferably used. The reason why the above range is preferable is that when the amount of styrene is increased, the elastic modulus of the pressure-sensitive adhesive is increased, and the pressure-sensitive adhesive can be prevented from entering the adherend, for example, the fiber or the uneven surface (anchor effect). This is thought to be because sometimes it can be removed lightly.

  Commercially available rubber adhesives include Asahi Kasei Co., Ltd. Tuftec series, Kuraray Co., Ltd. Septon series, Hibler series, Clayton Polymer Japan Co., Ltd. Clayton series, JSR Co., Ltd. For example, Dynalon series.

(2) Acrylic pressure-sensitive adhesive Acrylic pressure-sensitive adhesive is not particularly limited as long as it is cross-linked. Ethylene / ethyl acrylate copolymer (EEA), ethylene / methyl acrylate copolymer (EMA), ethylene ethyl methacrylate (EEMA), ethylene methyl methacrylate (EMMA)) and the like are preferably used. The composition of the acrylic pressure-sensitive adhesive is not particularly limited as long as the effects of the present invention are not impaired.

  Examples of commercially available acrylic pressure-sensitive adhesives include the Lexpearl series manufactured by Nippon Polyethylene Co., Ltd. and the ACLIFT series manufactured by Sumitomo Chemical Co., Ltd.

(3) Soft polypropylene resin The soft polypropylene resin is not particularly limited as long as the effects of the present invention are not impaired, but may be a crystalline soft polypropylene resin or an amorphous soft polypropylene resin. The melt flow rate (MFR: 230 ° C., 21.18 N load) is 2 to 30 g / min, the density is 0.85 to 0.89 g / cm 3, and the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) ( Mw / Mn) is preferably a propylene homopolymer having a molecular weight of 1.5 to 3 or a propylene / α-olefin random copolymer.

Examples of the α-olefin as the copolymer component include ethylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene and the like. Specific examples of the propylene / α-olefin random copolymer include propylene / ethylene random copolymer, propylene / 1-butene random copolymer, propylene / 1-hexene random copolymer, propylene / ethylene / 1-butene. A copolymer etc. are mentioned. Preferably, a propylene / ethylene random copolymer, a propylene / 1-butene random copolymer, a propylene / ethylene / 1-butene copolymer, and the like are used. In view of the balance between adhesive strength and adhesive residue, a propylene / ethylene random copolymer is most preferable.
If the melt flow rate (MFR) is less than 2 g / min, the melt viscosity is too high and it is difficult to form a film, and if it exceeds 30 g / min, the melt viscosity is too low and defects such as punching occur in the process of film formation. Density becomes the adhesive residue is generated to the adherend becomes too strong and adhesion strength is less than 0.85 g / cm ^3, the adhesive strength is not expressed required as a pressure-sensitive adhesive layer exceeds 0.89 g / cm ^3. The density is preferably 0.86 to 0.88 g / cm ³ from the balance of adhesive residue and adhesive strength. When the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is less than 1.5, a stable thickness cannot be secured when the adhesive layer is laminated. If it exceeds 3, there is a problem that powder blowing due to bleed-out occurs and the adherend is contaminated.

  The melt flow rate (MFR: unit g / 10 min) is a value measured according to JIS K-7210-1995 (230 ° C., 21.18 N load) and the density is JIS-K6922-2: 1997 appendix. The value measured according to (23 ° C.), Mw / Mn, is a value measured under the same conditions as gel permeation chromatography (GPC) of the propylene-based resin used for the base material layer.

  As soft polypropylene resins, commercially available products such as Tough selenium series manufactured by Sumitomo Chemical Co., Ltd., VISTAMAXX series manufactured by ExxonMobil Chemical, VERSIFY series manufactured by The Dow Chemical Company, and Notio manufactured by Mitsui Chemicals, Inc. A series or the like is preferably used.

(4) Ethylene / vinyl acetate copolymer (EVA)
The ethylene / vinyl acetate copolymer (EVA) is not particularly limited as long as the effects of the present invention are not impaired, but the vinyl acetate content (VAC) is 10% to 47%, more preferably 15 to 20%. %. With EVA of VAC lower than 10%, the initial adhesive strength is too low and does not stick to the object to be protected. In addition, VAC EVA higher than 47% increases the adhesive strength after heat treatment and makes it difficult to peel off.

The melt flow rate (MFR: 190 ° C., 21.18 N load) of the ethylene / vinyl acetate copolymer (EVA) is preferably 7 to 20 g / 10 minutes, more preferably 4 to 15 g / 10 minutes. If the MFR becomes too small, sufficient initial adhesive force cannot be obtained. Conversely, if the MFR becomes too large, when the surface protective film is heat-treated, the pressure-sensitive adhesive layer melts and the substrate and the adherend are not bonded. Even after the protective film is peeled off, it remains on the surface of the adherend, and the fluidity of the pressure-sensitive adhesive increases, making extrusion molding difficult.
The MFR of the ethylene / vinyl acetate copolymer (EVA) is a value measured according to JIS-K6922-2: 1997 appendix (190 ° C., 21.18 N load).

  Examples of commercially available ethylene / vinyl acetate copolymers (EVA) include Novatec EVA series manufactured by Nippon Polyethylene Co., Ltd. and Evaate series manufactured by Sumitomo Chemical Co., Ltd.

(5) Ethylene polymer The ethylene polymer is not particularly limited as long as the effects of the present invention are not impaired, but an ethylene / α-olefin copolymer is preferably used and copolymerized with ethylene. The α-olefin is preferably an α-olefin having 3 to 20 carbon atoms, and examples thereof include propylene, butene-1, hexene-1, octene-1, and the like, and in particular, propylene, butene-1, or hexene-1 Is preferred. Further, the α-olefin copolymerized with ethylene may be one type or two or more types.
The ethylene content in the ethylene / α-olefin random copolymer is preferably 50% by weight or more. If the ethylene content is low, the adhesive strength tends to be weak, so the effect as an adhesive layer may be inferior. The content of α-olefin is appropriately adjusted according to the required density.

The ethylene / α-olefin copolymer is polymerized using a metallocene catalyst, has a density of 0.860 to 0.918 g / cm ³ , and is 20 ° C. in temperature rising elution fractionation (TREF) measurement using orthodichlorobenzene as a solvent. The following elution amount is preferably 60% by weight or less, and the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is preferably 3.5 or less.
By using the ethylene / α-olefin copolymer layer in the pressure-sensitive adhesive layer, when at least one of the base material layer and the pressure-sensitive adhesive layer is laminated in a molten state, the adhesive layer and the base material layer are firmly bonded. From the rolled state in which both are in contact with each other in a solid state, it can be a surface protective film having the property of peeling smoothly when the roll is unwound, and the peel strength with the base material layer is improved in the surface protective film manufacturing process, When a surface protective film is used, the feeding property is improved.

The density of the ethylene / α-olefin copolymer is adjusted according to the strength of the adhesive force, and is not particularly limited, but is preferably 0.860 to 0.918 g / cm ³ , more preferably 0.865 to 0.905 g. / Cm ³ , more preferably 0.870 to 0.898 g / cm ³ . When the density is less than 0.860 g / cm ³ , the adhesive strength becomes too high, and there is a problem that the material is peeled off from the base material layer and a mark remains on the protected object. In addition, when the density exceeds 0.918 / cm ³ , the adhesive strength becomes too weak and the effect as an adhesive layer cannot be obtained.
In addition, a density is a value measured based on JIS-K6922-2: 1997 appendix (23 degreeC).

Further, the melt flow rate (MFR: 190 ° C., 21.18 N load) of the ethylene / α-olefin copolymer is preferably 0.1 to 50 g / 10 minutes, more preferably 1 to 30 g / 10 minutes, Most preferably, it is 2-15 g / 10min. When the MFR is less than 0.1 g / 10 min, the extrusion characteristics are likely to deteriorate, and there is a problem in that the interface with the base film made of the propylene resin of the present invention is roughened. If it exceeds 50 g / 10 min, it causes thickness unevenness.
In addition, MFR of an ethylene polymer is a value measured based on JIS-K6922-2: 1997 appendix (190 degreeC, 21.18N load).

Further, the elution amount at 20 ° C. or less in the temperature rising elution fractionation (TREF) measurement using orthodichlorobenzene of the ethylene / α-olefin copolymer as a solvent is preferably 60% by weight or less, more preferably 50% by weight or less. Particularly preferably, it is 15% by weight or less.
Further, the elution amount of 65 ° C. or higher by temperature rising elution fractionation (TREF) of the ethylene / α-olefin copolymer is 0.5 wt% or more, preferably 2.0 wt% or more, more preferably 5.0 wt%. % Or more. If it is the said range, since favorable adhesive strength can be maintained, it is preferable.

Here, the amount of elution by TREF is measured by the following cross-fractionation chromatograph (CFC) comprising a temperature rising elution fractionation (TREF) portion for performing crystalline fractionation and a gel permeation chromatography (GPC) portion for performing molecular weight fractionation. Depending on the method.
First, a polymer sample was completely dissolved in orthodichlorobenzene (ODCB) containing 0.5 mg / mL BHT at 140 ° C., and this solution was passed through a sample loop of the apparatus, and a TREF column (inert) maintained at 140 ° C. The polymer sample is crystallized by slowly cooling to a predetermined first elution temperature. After maintaining at a predetermined temperature for 30 minutes, ODCB is passed through a TREF column, whereby the eluted component is injected into the GPC section to perform molecular weight fractionation. An infrared detector (MIRAN 1A IR detector manufactured by FOXBORO, A chromatogram is obtained with a measuring wavelength of 3.42 μm). Meanwhile, in the TREF part, the temperature is raised to the next elution temperature, and after obtaining the chromatogram of the first elution temperature, the elution component at the second elution temperature is injected into the GPC part. Thereafter, the same operation is repeated to obtain a chromatogram of the eluted components at each elution temperature.
The measurement conditions are shown below.
Equipment: CFC-T102L manufactured by Dia Instruments
GPC column: Showa Denko AD-806MS (3 connected in series)
Solvent: ODCB
Sample concentration: 3 mg / mL
Injection volume: 0.4mL
Crystallization rate: 1 ° C / min Solvent flow rate: 1 mL / min GPC measurement time: 34 minutes Stabilization time after GPC measurement: 5 minutes Elution temperature: 0, 5, 10, 15, 20, 25, 30, 35, 40, 45 49, 52, 55, 58, 61, 64, 67, 70, 73, 76, 79, 82, 85, 88, 91, 94, 97, 100, 102, 120, 140
Data analysis: The chromatograms of the elution components obtained at each elution temperature obtained by measurement are processed by the data processing program attached to the instrument, and the elution amount is standardized so that the total is 100% (proportional to the area of the chromatogram) ) Is required. In addition, an integrated elution curve for the elution temperature is calculated. An elution amount of 20 ° C. or lower and an elution amount of 65 ° C. or higher are determined from the obtained elution curve.

Further, the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the ethylene / α-olefin copolymer is preferably 3.5 or less, more preferably 1.5 to 3 0.0, particularly preferably 2.0 to 2.5. If it is the said range, there will be no stickiness and it is preferable.
Here, Mw / Mn is defined by the ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) measured by gel permeation chromatography (GPC). The measuring method of Mw / Mn is as follows.
Apparatus: Waters GPC 150C type Detector: MIRAN 1A infrared spectrophotometer (measurement wavelength, 3.42 μm)
Column: AD806M / S manufactured by Showa Denko Co., Ltd. (column calibration is performed by Tosoh monodisperse polystyrene (0.5 mg / ml solution of each of A500, A2500, F1, F2, F4, F10, F20, F40, and F288) Measurement was performed, and the logarithm of the elution volume and the molecular weight was approximated by a quadratic equation. The molecular weight of the sample was converted to polyethylene using the viscosity formula of polystyrene and polyethylene. Here, the coefficients of the viscosity formula of polystyrene are α = 0.723 and log K = −3.767, and polyethylene has α = 0.723 and log K = −3.407.
Measurement temperature: 140 ° C
Injection volume: 0.2ml
Concentration: 20 mg / 10 mL
Solvent: Orthodichlorobenzene Flow rate: 1.0 ml / min

  The ethylene / α-olefin copolymer is prepared by using a catalyst such as a Ziegler catalyst, a Phillips catalyst, or a metallocene catalyst in a process such as a gas phase method, a solution method, a high pressure method, or a slurry method. Can be produced by copolymerizing with α-olefin such as 1-hexene, 4-methyl-1-pentene, 1-octene, etc., but especially produced by high pressure method or solution method using metallocene catalyst Is preferable because both the molecular weight distribution and the crystallinity distribution are narrow.

In the above ethylene / α-olefin copolymer, MFR, density, elution amount of TREF 20 ° C. or less, Mw / Mn change polymerization temperature, polymerization pressure, catalyst used, and type and composition of ethylene and α-olefin. By doing so, it can be adjusted easily.
For example, the density tends to increase as the polymerization temperature is increased, reducing the α-olefin feed rate. In addition, the amount of elution below TREF of 20 ° C. tends to increase as the α-olefin supply amount is increased or the polymerization temperature is lowered. Furthermore, the MFR tends to decrease with increasing polymerization pressure.

  When the pressure-sensitive adhesive layer is mainly composed of an ethylene / α-olefin copolymer polymerized using the metallocene catalyst, only the ethylene / α-olefin copolymer may be used, and other components may be used. May be. Examples of other components include low density polyethylene.

Examples of commercially available ethylene polymers include Novatec LL series, Harmolex series, Kernel series, Tuffmer P series and Tuffmer A series manufactured by Mitsui Chemicals, and Prime Polymer Co., Ltd. Examples include Volume Series, Sumikasen E, EP Series, Excellen GMH Series, Excellen FX Series, etc., manufactured by Sumitomo Chemical Co., Ltd.
Among these, an ethylene / α-olefin copolymer polymerized using a metallocene catalyst is preferable. In particular, Harmolex series, Kernel series manufactured by Nippon Polyethylene Co., Ltd., Evolue series manufactured by Prime Polymer Co., Ltd., Sumitomo Exelen GMH series, Exelen FX series, etc. manufactured by Chemical Co., Ltd. are preferable.

  These pressure-sensitive adhesives can be used singly or in combination of two or more, as long as the effects of this object are not impaired.

  The pressure-sensitive adhesive layer can be used as a pressure-sensitive adhesive layer in consideration of adhesion to the base material layer by blending a pressure-sensitive adhesive with the propylene-based resin used in the present invention. When the above-mentioned pressure-sensitive adhesive is used in combination with the propylene-based resin used in the present invention, when the total of the propylene-based resin and the pressure-sensitive adhesive used in the present invention is 100% by weight, the content of the propylene-based resin (A) Is 1 to 99% by weight, and the content of the pressure-sensitive adhesive is 99 to 1% by weight.

3. Release treatment layer
In the surface protective film of this invention, a peeling process layer is formed in the other surface of the adhesion layer formed in one side of the base material layer which consists of the said propylene-type resin as needed. The release treatment layer is not particularly limited as long as it is a known one, and for example, a layer formed with a silicone-based or long-chain alkyl release treatment agent or a film surface is roughened to form unevenness and improve releasability. The layer formed from a silicone-based or long-chain alkyl-based release treatment agent is preferable from the viewpoint of transparency.

As the silicone release treatment agent , a commonly used silicone release treatment agent mainly composed of dimethylpolysiloxane can also be used. It is also possible to use a silicone release treatment agent containing a three-dimensional organopolysiloxane. Specifically, a silicone-based release treatment agent containing organopolysiloxane as a main component and blended with a cellulose derivative such as methyl cellulose, ethyl cellulose, acetyl cellulose, alkyd resin, or the like is preferably used. By incorporating a cellulose derivative, an alkyd resin, or the like, it is possible to control the release property of the silicone release agent. The cellulose derivative and alkyd resin are preferably blended in an amount of 5 to 50% by weight in the silicone-based release treatment agent .

Depending on the type of curing reaction (crosslinking reaction) of the organopolysiloxane, it is roughly divided into a condensation reaction type and an addition reaction type, but in the present invention, any reaction type may be used.
For example, as the condensation reaction type silicone release agent, for example, a silicone release agent in which a cellulose derivative or an alkyd resin is blended with an organopolysiloxane having a silanol group at a molecular terminal is mentioned. Here, as the organopolysiloxane having a silanol group at the molecular end, a polysiloxane in which an alkyl group such as a methyl group or an ethyl group or a phenyl group is introduced as a side chain functional group (for example, dimethyl diphenylpolysiloxane) is used. It is preferable that the release agent has a good compatibility with the cellulose derivative and the alkyd resin, and a stable release property. In addition, the organopolysiloxane having a silanol group at the molecular end is appropriately blended with a crosslinking agent such as an alkoxy group-containing organopolysiloxane, or a catalyst such as dibutyltin dilaurate, dibutyltin diacetate, dibutyltin dioctate, or zinc octylate. May be. Moreover, resin, such as an acrylic resin, can also be suitably mix | blended as a 3rd component as needed. In the silicone release agent, the crosslinking agent is preferably 4 to 20% by weight, the catalyst is preferably 5 to 10% by weight, and the resin as the third component is preferably 5 to 26% by weight.

  As an addition reaction type silicone release agent, for example, a silicone release agent in which a cellulose derivative or alkyd resin is blended with organopolysiloxane having at least two alkenyl groups such as vinyl groups bonded to silicon atoms in one molecule. Agents. Here, as the above-mentioned organopolysiloxane, it is preferable to use an organopolysiloxane having an alkyl group such as a methyl group or an ethyl group or a phenyl group introduced as a functional group of the side chain, whereby cellulose derivatives or alkyds are used. A release agent having good compatibility with the resin and stable release characteristics can be obtained. The organopolysiloxane may be appropriately blended with a crosslinking agent such as an organohydrodiene polysiloxane and a catalyst such as a platinum compound such as chloroplatinic acid.

The silicone-based release treatment agent can be appropriately selected from commercially available products. For example, as a condensation reaction type silicone release agent, KS available from Shin-Etsu Chemical Co., Ltd., KS -723A / B (consisting of dimethyl diphenylpolysiloxane, methoxysilicone and ethylcellulose) is X-62-9201A / B available from Shin-Etsu Chemical Co., Ltd. as an addition reaction type silicone release agent. be able to.

Examples of the long-chain alkyl release agent include a polymer of a long-chain alkyl acrylate having 12 or more carbon atoms, a copolymer of a long-chain alkyl acrylate and another vinyl monomer, or a long-chain alkyl isocyanate to polyvinyl alcohol. And a release agent obtained from a reaction product obtained by reacting the long-chain alkyl component.
For example, BP type manufactured by Nitto Denko Corporation, ashioresin manufactured by Ashio Sangyo Co., Ltd., and Pyroleil manufactured by Yushi Co., Ltd. can be used.

  As a layer which roughened the film surface and formed unevenness and improved releasability, as a resin used to obtain the film, a propylene / α-olefin block copolymer alone, or a propylene resin used in the present invention A blend of a propylene / α-olefin block copolymer, a low density polyethylene alone, a high density polyethylene alone, or a blend of low density polyethylene or high density polyethylene in the propylene resin used in the present invention, or propylene・ Low-density polyethylene or high-density polyethylene blended with α-olefin block copolymer, or propylene / α-olefin block copolymer, low-density polyethylene, high-density polyethylene with propylene resin used in the present invention 2 or more types Things, or a different thermoplastic resin compatibility propylene resin used in the present invention can be used after blending.

Roughened surface of the film to improve the formed peelable irregularities, unevenness of the film surface is 0.1~1.5μm in center surface average roughness (S Ra). Preferably it is 0.3-1.2 micrometers, More preferably, it is 0.5-1.0 micrometer, Most preferably, it is 0.8-1.0 micrometer.
The center plane average roughness measuring method of (S Ra) is the value obtained by the measurement method and measurement conditions are different, in the present invention, a stylus-type specified in JIS-B-0651 (2001) Measure with a surface roughness meter. The measurement conditions of the measuring instrument are: stylus tip radius of curvature of 5 μm, cutoff wavelength of 0.80 mm, cutoff type of 2CR (phase compensation), measuring speed of 0.3 mm / second, measuring direction of film MD direction, The measurement length was 2 mm, and the range of surface roughness was defined by the obtained value. The MD direction, which is the measurement direction, refers to the film feed direction when extruding a resin composition containing a propylene-ethylene block copolymer as a main component, that is, the direction parallel to the longitudinal direction of the film.

  In addition, the release treatment layer can be used as a release treatment layer by blending a release treatment agent with the propylene-based resin used in the present invention in consideration of adhesion to the base material layer. When the above-mentioned release treatment agent is used in combination with the propylene resin used in the present invention, when the total of the propylene resin and release treatment agent used in the present invention is 100% by weight, the content of the propylene resin is 1 to 99% by weight, and the content of the release treatment agent is 99 to 1% by weight.

4). Resin compounding agent that can be used in each layer The base material layer, the pressure-sensitive adhesive layer, and the release treatment layer that is used as necessary in the present invention include film-forming stability of the film, and handling during secondary processing. And various additives used as a known resin compounding agent, for example, an antioxidant, an antiblocking agent, a slip agent, and a nucleating agent as long as the purpose of the present invention is not impaired from the maintenance of quality as a surface protective film. , Neutralizers, light stabilizers, antistatic agents, tackifiers and the like may be contained. Various additives are described in detail below.

(1) Antioxidants As antioxidants, specific examples of phenolic antioxidants include tris- (3,5-di-t-butyl-4-hydroxybenzyl) -isocyanurate, 1,1,3- Tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane, octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, pentaerythrityl-tetrakis {3- ( 3,5-di-tert-butyl-4-hydroxyphenyl) propionate}, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene 3,9-bis [2- {3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy} -1,1-dimethylethyl] -2,4,8,10- Examples thereof include tetraoxaspiro [5,5] undecane, 1,3,5-tris (4-t-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanuric acid and the like.

Specific examples of phosphorus antioxidants include tris (mixed, mono and dinonylphenyl phosphite), tris (2,4-di-t-butylphenyl) phosphite, 4,4′-butylidenebis (3- Methyl-6-tert-butylphenyl-di-tridecyl) phosphite, 1,1,3-tris (2-methyl-4-di-tridecylphosphite-5-tert-butylphenyl) butane, bis (2, 4-di-t-butylphenyl) pentaerythritol-di-phosphite, tetrakis (2,4-di-t-butylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2,4-di-t -Butyl-5-methylphenyl) -4,4'-biphenylenediphosphonite, bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol-di-phos You can list s fights.
Specific examples of the sulfur-based antioxidant include di-stearyl-thio-di-propionate, di-myristyl-thio-di-propionate, pentaerythritol-tetrakis- (3-lauryl-thio-propionate), and the like. it can.
These antioxidants can be used singly or in combination of two or more as long as the effects of the present object are not impaired.

  The compounding quantity of antioxidant is 0.01-1.0 weight part with respect to 100 weight part of each resin used for each layer of a base material layer, an adhesive layer, and a peeling process layer, Preferably it is 0.02-0. 0.5 part by weight, more preferably 0.05 to 0.1 part by weight. When the blending amount of the antioxidant is within the above range, the thermal stability is improved and the deterioration of the resin causing fish eyes is suppressed.

(2) Antiblocking agent The average particle diameter of an antiblocking agent is 1-7 micrometers, Preferably it is 1-5 micrometers, More preferably, it is 1-4 micrometers. If the average particle diameter is less than 1 μm, the slipperiness and openability of the resulting film are inferior. On the other hand, if it exceeds 7 μm, the transparency and scratching property are remarkably inferior. Here, the average particle diameter is a value obtained by Coulter counter measurement.

Specific examples of the anti-blocking agent include, for example, inorganic or synthetic silica (silicon dioxide), magnesium silicate, aluminosilicate, talc, zeolite, aluminum borate, calcium carbonate, calcium sulfate, barium sulfate, calcium phosphate. Etc. are used.
Moreover, as an organic type, polymethyl methacrylate, polymethylsilyltosesquioxane (silicone), polyamide, polytetrafluoroethylene, epoxy resin, polyester resin, benzoguanamine / formaldehyde (urea resin), phenol resin, or the like may be used. it can.
In particular, synthetic silica and polymethyl methacrylate are preferable from the balance of dispersibility, transparency, blocking resistance, and scratch resistance.
The anti-blocking agent may be surface-treated, and as the surface treating agent, surfactant, metal soap, acrylic acid, oxalic acid, citric acid, tartaric acid and other organic acids, higher alcohols, esters, Condensed phosphates such as silicone, fluorine resin, silane coupling agent, sodium hexametaphosphate, sodium pyrophosphate, sodium tripolyphosphate, sodium trimetaphosphate, etc. can be used, especially those treated with citric acid among organic acids Is preferred. The treatment method is not particularly limited, and a known method such as surface spraying or dipping can be employed.
The anti-blocking agent may have any shape, and can be any shape such as a spherical shape, a square shape, a columnar shape, a needle shape, a plate shape, and an indefinite shape.
These anti-blocking agents can be used singly or in combination of two or more in a range that does not impair the effects of this object.

  The compounding amount of the anti-blocking agent is 0.01 to 1.0 part by weight, preferably 0.05 to 0 with respect to 100 parts by weight of each resin used in each layer of the base material layer, the pressure-sensitive adhesive layer and the release treatment layer. 0.7 parts by weight, more preferably 0.1 to 0.5 parts by weight. When the blending amount of the anti-blocking agent is within the above range, the blocking property is improved and the feeding property is improved.

(3) The slip agent slip agents, monoamides include, bisamide compounds, and the like. These may be those substituted. Among these, it can be used 1 type or in combination of 2 or more types.
Specific examples of monoamides include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, hydroxystearic acid amide and the like as saturated fatty acid monoamides.
Examples of the unsaturated fatty acid monoamide include oleic acid amide, erucic acid amide, ricinoleic acid amide and the like.
Specific examples of substituted amides among monoamides include N-stearyl stearic acid amide, N-oleyl oleic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl erucic acid amide, N-oleyl Examples include palmitic acid amide.
Specific examples of bisamides include, as saturated fatty acid bisamides, methylene bis stearic acid amide, ethylene biscapric acid amide, ethylene bis lauric acid amide, ethylene bis stearic acid amide, ethylene bisisostearic acid amide, ethylene bishydroxystearic acid amide, Ethylene bisbehenic acid amide, hexamethylene bis stearic acid amide, hexamethylene bis behenic acid amide, hexamethylene bishydroxy stearic acid amide, N, N'-distearyl adipic acid amide, N, N'-distearyl Sepacic acid amide and the like can be mentioned.
The unsaturated fatty acid bisamide, ethylene bis-oleic acid amide, hexamethylene bis amide oleate.
Specific examples of substituted amides among bisamides include N, N′-dioleyl adipate amide, N, N′-dioleyl sepasin amide, and the like.
Examples of the aromatic bisamide include m-xylylene bis stearic acid amide and N, N′-distearylisophthalic acid amide.
Among these, oleic acid amide, erucic acid amide, and behenic acid amide are particularly preferably used among the fatty acid amides.

  As a compounding quantity of a slip agent, 0.01-1.0 weight part with respect to 100 weight part of each resin used for each layer of a base material layer, an adhesive layer, and a peeling process layer, Preferably 0.05- 0.7 part by weight, more preferably 0.1 to 0.4 part by weight. When the blending amount of the slip agent is within the above range, the slipping property is improved and the feeding property is improved.

(4) Nucleating agent Specific examples of the nucleating agent include sodium 2,2-methylene-bis (4,6-di-t-butylphenyl) phosphate, talc, 1,3,2,4-di (p-methyl). A sorbitol compound such as benzylidene) sorbitol, hydroxy-di (t-butylaluminum benzoate), 2,2-methylene-bis (4,6-di-t-butylphenyl) phosphoric acid and an aliphatic mono-carbon having 8 to 20 carbon atoms. Examples thereof include a carboxylic acid lithium salt mixture (manufactured by ADEKA, trade name NA21).
As a compounding quantity of the said nucleating agent, 0.0005-0.5 weight part with respect to 100 weight part of each resin used for each layer of a base material layer, an adhesive layer, and a peeling process layer, Preferably it is 0.001. It is -0.1 weight part, More preferably, it is 0.005-0.05 weight part. When the blending amount of the nucleating agent is within the above range, the crystallization speed is increased and the transparency is improved.

Moreover, a high density polyethylene resin can be mentioned as a nucleating agent other than the above. The density of the high-density polyethylene resin is 0.94 to 0.98 g / cm ³ , preferably 0.95 to 0.97 g / 10 cm ³ . If the density is out of this range, the effect of improving transparency cannot be obtained. The 190 degreeC melt flow rate (MFR) of a high density polyethylene resin is 5 g / 10min or more, Preferably it is 7-500 g / 10min, More preferably, it is 10-100 g / 10min. When the MFR is less than 5 g / 10 min, the dispersion diameter of the high-density polyethylene resin is not sufficiently small, and it itself becomes a foreign matter and causes fish eyes. In order to finely disperse the high-density polyethylene resin, the MFR of the high-density polyethylene resin is preferably larger than the MFR of the propylene-based resin of the present invention.

  The production of the high-density polyethylene resin used as the nucleating agent is not particularly limited with respect to the polymerization method and catalyst as long as a polymer having the desired physical properties can be produced. For catalysts, Ziegler type catalysts (ie, based on a combination of supported or unsupported halogen-containing titanium compounds and organoaluminum compounds), Kaminsky type catalysts (ie, supported or unsupported metallocene compounds and organoaluminum compounds, especially alumoxanes). Based on the combination). There is no restriction | limiting about the shape of a high density polyethylene-type resin, A pellet form may be sufficient and a powder form may be sufficient.

  The blending amount of the high density polyethylene used as the nucleating agent is 0.01 to 5 parts by weight, preferably 100 parts by weight of each resin used in each layer of the base material layer, the pressure-sensitive adhesive layer and the release treatment layer. 0.05 to 3 parts by weight, more preferably 0.1 to 1 part by weight. When the blending amount of the high density polyethylene is within the above range, the crystallization speed is increased and the transparency is improved. Further, in the case of coextrusion molding, there is no transfer of the sweeper roll.

(5) Neutralizing agent Specific examples of the neutralizing agent include calcium stearate, zinc stearate, hydrotalcite, Mizukarak (manufactured by Mizusawa Chemical Co., Ltd.), and the like.
The blending amount of the neutralizing agent is 0.01 to 1.0 parts by weight, preferably 0.02 to 0 parts per 100 parts by weight of each resin used in each of the base layer, the pressure-sensitive adhesive layer and the release treatment layer. 0.5 part by weight, more preferably 0.05 to 0.1 part by weight. When the blending amount of the neutralizing agent is within the above range, the effect as an internal lubricant is improved, and scraping of deteriorated materials inside the extruder is suppressed.

(6) Light Stabilizer As the light stabilizer, a hindered amine stabilizer is preferably used, and a structure in which all hydrogen bonded to carbons at the 2-position and 6-position of a conventionally known piperidine is substituted with a methyl group. Although the compound which has this is used without being specifically limited, the following compounds are specifically used.
Specific examples include polycondensates of dimethyl oxalate and 1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine, tetrakis (1,2,2,6,6). -Pentamethyl-4-piperidyl) 1,2,3,4-butanetetracarboxylate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, N, N-bis (3-aminopropyl) ) Ethylenediamine · 2,4-bis [N-butyl-N- (1,2,2,6,6-pentamethyl-4-piperidyl) amino] -6-chloro-1,3,5-triazine condensate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, poly [{6- (1,1,3,3-tetramethylbutyl) imino-1,3,5-triazine-2,4- Jil} {(2,2, , 6-tetramethyl-4-piperidyl) imino} hexamethylene {2,2,6,6-tetramethyl-4-piperidyl} imino], poly [(6-morpholino-s-triazine-2,4-diyl) And [(2,2,6,6-tetramethyl-4-piperidyl) imino] hexamethylene {(2,2,6,6-tetramethyl-4-piperidyl) imino}].
These hindered amine stabilizers can be used singly or in combination of two or more in a range not impairing the effect of the present object.

The blending amount of the hindered amine stabilizer is 0.005 to 2 parts by weight, preferably 0.01 to 1 part by weight with respect to 100 parts by weight of each resin used in the base layer, the pressure-sensitive adhesive layer and the release treatment layer. Parts, more preferably 0.05 to 0.5 parts by weight.
When the content of the hindered amine stabilizer is within the above range, stability such as heat resistance and aging resistance is improved.

(7) Antistatic agent The antistatic agent can be used without particular limitation as long as it is a known antistatic agent or antistatic agent conventionally used, and examples thereof include anionic surfactants and cations. Ionic surfactants, nonionic surfactants, amphoteric surfactants and the like.

  Examples of the anionic surfactant include fatty acid or rosin acid soap, N-acyl carboxylate, ether carboxylate, carboxylate such as fatty acid amine salt; sulfosuccinate, ester sulfonate, N-acyl sulfonate Sulfonates such as salts; sulfated oils, sulfate esters, alkyl sulfate salts, sulfate sulfate polyoxyethylene salts, sulfate ether salts, sulfate ester salts such as sulfate amide salts; alkyl phosphate salts, alkyl polyoxyethylene phosphates Examples thereof include phosphoric acid ester salts such as salts, phosphoric acid ether salts and phosphoric acid amide salts.

  Examples of the cationic surfactant include amine salts such as alkylamine salts; alkyltrimethylammonium chloride, alkylbenzyldimethylammonium chloride, alkyldihydroxyethylmethylammonium chloride, dialkyldimethylammonium chloride, tetraalkylammonium salt, N, N-di Quaternary ammonium salts such as (polyoxyethylene) dialkylammonium salts and N-alkylalkanamide ammonium salts; 1-hydroxyethyl-2-alkyl-2-imidazoline, 1-hydroxyethyl-1-alkyl-2-alkyl Examples include alkyl imidazoline derivatives such as -2-imidazoline; imidazolinium salts, pyridinium salts, isoquinolinium salts, and the like.

  Examples of the nonionic surfactant include ether forms such as alkyl polyoxyethylene ether and p-alkylphenyl polyoxyethylene ether; fatty acid sorbitan polyoxyethylene ether, fatty acid sorbitol polyoxyethylene ether, fatty acid glycerin polyoxyethylene ether, etc. Ether ester form of fatty acid polyoxyethylene ester, monoglyceride, diglyceride, sorbitan ester, sucrose ester, dihydric alcohol ester, boric acid ester, etc .; dialcohol alkylamine, dialcohol alkylamine ester, fatty acid alkanolamide, N, N-di (polyoxyethylene) alkanamide, alkanolamine ester, N, N-di (polyoxyethylene) alkaneamine, amine oxy De, a nitrogen-formed and fabricated and alkyl polyethylene imine.

  Examples of the amphoteric surfactant include amino acid forms such as monoaminocarboxylic acid and polyaminocarboxylic acid; N-alkyl-β-alanine such as N-alkylaminopropionate and N, N-di (carboxyethyl) alkylamine salt. Forms: Betaine forms such as N-alkylbetaines, N-alkylamidobetaines, N-alkylsulfobetaines, N, N-di (polyoxyethylene) alkylbetaines, imidazolinium betaines; 1-carboxymethyl-1-hydroxy- And alkyl imidazoline derivatives such as 1-hydroxyethyl-2-alkyl-2-imidazoline and 1-sulfoethyl-2-alkyl-2-imidazoline.

  Among these, nonionic surfactants and amphoteric surfactants are preferable. Among them, monoglycerides, diglycerides, boric acid esters, dialcohol alkylamines, dialcohol alkylamine esters, amides and the like or nitrogen-containing non-type surfactants are preferred. Ionic surfactants; betaine amphoteric surfactants are preferred.

  In addition, as an antistatic agent, a commercial item can be used, for example, electro stripper TS5 (trade name, glycerin monostearate manufactured by Kao Corporation), electro stripper TS6 (trade name, stearyl manufactured by Kao Corporation). Diethanolamine), electro stripper EA (trade name, lauryl diethanol amine, manufactured by Kao Corporation), electro stripper EA-7 (trade name, polyoxyethylene lauryl amine capryl ester, manufactured by Kao Corporation), Denon 331P (maruhishi oil ( Co., Ltd., trademark, stearyl diethanolamine monostearate), Denon 310 (manufactured by Maruhishi Oil Chemical Co., Ltd., trademark, alkyldiethanolamine fatty acid monoester), Register PE-139 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., trademark) , Stearic acid mono & diglyceride Ester), Chemistat 4700 (Sanyo Chemical Industries Co., Ltd., trademark, alkyl dimethyl betaine), rheostat S (Lion Co., Ltd., trademark, alkyl diethanolamide), and the like.

  The blending amount of the antistatic agent is 0.01 to 2 parts by weight, preferably 0.05 to 1 part by weight with respect to 100 parts by weight of each resin used for each layer of the base material layer, the pressure-sensitive adhesive layer and the release treatment layer. More preferably, it is 0.1-0.8 weight part, Most preferably, it is 0.2-0.5 weight part. These antistatic agents can be used singly or in combination of two or more in a range that does not impair the effects of this object. When the blending amount of the antistatic agent is within the above range, it is possible to prevent electrification and suppress deposits such as dust.

(8) Tackifier The tackifier includes, for example, aliphatic petroleum resins, alicyclic hydrogenated petroleum resins, aromatic petroleum resins, C5 petroleum resins, terpene resins, coumarone / indene resins, A phenol resin, a rosin resin, a tackifier, etc. are mentioned, These can be used 1 type or in combination of 2 or more types in the range which does not impair the effect of this invention remarkably.

The amount of tackifier is not particularly limited as long as it does not impair the effects of the present invention, the substrate layer, with respect to 100 parts by weight of the resin of each used in each layer of the pressure-sensitive adhesive layer and a release treatment layer 0.0001 to 200 parts by weight. Preferably it is 0.01-150 weight part, More preferably, it is 1-150 weight part, Most preferably, it is 10-100 weight part. The amount of tackifier in the above range improves the adhesion.

(9) Others Further, an elastomer is blended as a component for imparting flexibility, an ultraviolet absorber, a metal deactivator, a peroxide, a filler, an antibacterial and antifungal agent, as long as the effects of the present invention are not significantly impaired. Agents, fluorescent brighteners, antifogging agents, flame retardants, colorants, pigments, natural oils, synthetic oils, waxes and the like can be blended, and the blending ratio is an appropriate amount.

The blending of the above various additives can be directly added to the propylene resin of the present invention obtained by polymerization and melt kneaded for use, or may be added during melt kneading. Furthermore, it can be added directly after melt-kneading, or can be added as a masterbatch within a range that does not significantly impair the effects of the present invention. Moreover, you may add by these composite methods.
In general, additives such as an antioxidant and a neutralizing agent are blended, mixed, melted and kneaded, and then molded into a product for use. It is also possible to add and use other resins or other additional components (including a masterbatch) as long as the effects of the present invention are not significantly impaired during molding.

  For the above mixing, melting, and kneading, any conventionally known method can be used. Usually, Henschel mixer, super mixer, V blender, tumbler mixer, ribbon blender, Banbury mixer, kneader blender, uniaxial or biaxial kneading. It can be carried out in an extruder. Among these, it is preferable to perform mixing or melt-kneading with a uniaxial or biaxial kneading extruder.

5. Production of Surface Protection Film The surface protection film of the present invention can be produced by a known method for producing a laminated film.
For example, it manufactures by well-known techniques, such as a T die-cast method, a water cooling inflation method, an air cooling inflation method.
Among them, the T-die casting method in which a resin melted and kneaded by an extruder is extruded from a T-die and cooled by being brought into contact with a roll through a coolant such as water to produce a film generally has good transparency. A film with good thickness accuracy can be produced. Such a method is a preferable manufacturing method for the film.

  Here, the thickness of the film for surface protection is not particularly limited, but is 10 to 500 μm, preferably 20 to 200 μm, more preferably 30 to 100 μm, and most preferably 40 to 80 μm. If the thickness is outside this range, processing becomes difficult.

As a means for providing the pressure-sensitive adhesive layer on one side of the base material layer, as a method obtained by coating by a solution coating method or the like, a pressure-sensitive adhesive dissolved in an organic solvent such as a toluene solution is applied to one side of the base material layer by a roll coater or the like. The method of drying after application | coating and forming an adhesion layer can be mentioned. At that time, in order to improve the affinity between the base material layer and the pressure-sensitive adhesive layer, conventionally known corona discharge treatment, plasma discharge treatment, primer treatment, etc. are performed on one surface of the base material layer (adhesion surface with the pressure-sensitive adhesive layer). It may be.
Moreover, as a method for obtaining the pressure-sensitive adhesive layer by lamination, the pressure-sensitive adhesive is heated and melted by an extruder, extruded into a film form from a T die, and laminated on one side of the base material layer, or the substrate is obtained by an extruder. Examples thereof include a method in which the layer and the pressure-sensitive adhesive are heated and melted and coextruded into a film shape from a T-die together with the base material layer.

  The thickness of the pressure-sensitive adhesive layer is not particularly limited because the adhesive strength varies depending on the application, but is usually 0.1 to 100 μm, preferably 1 to 50 μm, more preferably 5 to 30 μm, and most preferably 10 to 20 μm. .

Examples of means for forming a release treatment layer provided on the other side of the pressure-sensitive adhesive layer of the surface protective film of the present invention include known methods such as coating, curing, and lamination.
As a method for obtaining the release treatment layer by coating, a release treatment agent dissolved in an organic solvent such as a toluene solution is applied to one side of the base material layer with a roll coater, and then dried to cure the release treatment agent and release. The method of forming a process layer can be mentioned. At that time, in order to improve the affinity between the base material layer and the release treatment layer, conventionally known corona discharge treatment, plasma discharge treatment, primer treatment, etc. are performed on one side of the base material layer (adhesion surface with the release treatment layer). May be.
In addition, as a method for obtaining a release treatment layer by lamination, a release treatment agent is heated and melted by an extruder and laminated on a single side of a base material layer in a film form from a T die, or by an extruder. Examples thereof include a method in which the material layer and the release treatment layer are heated and melted and coextruded into a film shape from a T die together with the base material layer.
In the present invention, adopting a method of roughening the surface of the release treatment layer to form unevenness and imparting release properties is advantageous in terms of contamination problems and economical points, and is suitable for the production of the release treatment layer. In addition, a method of co-extrusion with a T-die and lamination is preferable.

For method of applying the release treatment layer in a subsequent step, the coating amount of the release agent is generally in the case of silicone, 0.01 to 10 g / ^{m 2,} preferably from 0.1 to 3 g / ^{m 2.} In the case of long-chain alkyl-based, 0.005~10g / ^{m 2,} preferably 0.02~0.3g / ^{m 2,} particularly preferably preferably 0.01 to 0.1 g / ^{m 2.}

Although the thickness of the said peeling process layer is not specifically limited, Usually, 0.1-100 micrometers, Preferably it is 1-50 micrometers, More preferably, it is 5-30 micrometers, Most preferably, it is 10-20 micrometers. 6). Application of surface protection film
The film for surface protection of the present invention is stuck so that the pressure-sensitive adhesive layer is in contact with the surface of the adherend. Examples of the adherend include building members and liquid crystal display components. Examples of the building member include a synthetic resin plate, a decorative plate, a metal plate, and a glass plate. Further, examples of the constituent member of the liquid crystal display include a polarizing plate and a retardation plate.

  Examples of the present invention will be specifically described below, but the present invention is not limited to these examples. The physical property measurement methods, characteristic evaluation methods, and resin materials used in Examples and Comparative Examples are as follows.

1. Physical property measurement method, characteristic evaluation method (1) MFR: Propylene resin is measured at 230 ° C. under a load of 21.18 N in accordance with JIS K-7210-1995, and ethylene / α-olefin copolymer is measured according to JIS K-6922-2: Measured at 190 ° C. under a load of 21.18 N in accordance with the appendix of 1997.
(2) Density: Measured according to JIS K-6922-2: 1997 appendix (23 ° C.).
(3) Melting peak temperature: Using a differential scanning calorimeter (Seiko DSC), a sample amount of 5.0 mg was taken, held at 200 ° C. for 5 minutes, and then crystallized at a rate of temperature decrease of 10 ° C./min to 40 ° C. And the melting peak temperature (Tmp) when melted at a heating rate of 10 ° C./min was measured.
(4) Weight average molecular weight (Mw) / Number average molecular weight (Mn): Measured by the method described above.
(5) Temperature rising elution fractionation method: Measured by the method described above.
(6) n-decane soluble content: 200 ml of n-decane was added to 5 g of the sample and heated while stirring to completely dissolve the sample. It was cooled to 20 ° C. over about 3 hours and left for 30 minutes. Thereafter, the precipitate was filtered off. The filtrate was put in 1000 ml of acetone to precipitate the components dissolved in n-decane. The precipitate and acetone were filtered off and the precipitate was dried. Even when the filtrate side was concentrated to dryness, no residue was observed. The amount of n-decane solubles was determined by the following formula.
n-decane soluble content (% by weight) = [precipitate weight / sample weight] × 100
(7) Haze: The film was conditioned at 23 ° C. and 50% RH for 24 hours, and then measured with a haze meter in accordance with JIS-K7136-2000.
The smaller the value obtained, the better the transparency.
(8) Tensile elastic modulus: The film was measured for tensile elastic modulus in the flow direction (MD) under the following conditions in accordance with ISO 527.
The higher the obtained numerical value, the higher the rigidity of the film and the easier it is to handle it as a surface protecting film.
Sample length: 150mm
Sample width: 10mm
Distance between chucks: 100mm
Crosshead speed: 25mm / min
(9) Fish Eye: The number of fish eyes was counted from the area of 1 m ^{2 of the} film. The obtained fish eye is visually observed to have a major axis of 0.4 mm or more (≧ 0.4 mm), smaller than 0.4 mm, 0.2 mm or more (<0.4 mm to ≧ 0.2 mm), smaller than 0.2 mm, and 0. Each size was classified into 1 mm or more (<0.2 mm to ≧ 0.1 mm), and the number of each was divided (unit: pieces / m ² ).
When the number of fish eyes is small, even if the surface protective film is attached to the object to be protected and stacked and stored, the object to be protected does not dent, and is better as the surface protective film.
(10) Tackiness: Acrylic resin plate (mirror surface acrylic plate (manufactured by Mitsubishi Rayon Co., Ltd. “Acrylic”), which has a longitudinal direction of the film, cut to a width of 25 mm and a length of 20 cm, and preheated to 60 ° C. LIGHT L001 ”3 mm plate) After aging the pasted film at a temperature of 23 ° C. and a humidity of 50% for 12 hours, in accordance with JIS Z0237, at a pulling speed of 300 mm / min, at a peeling angle of 180 ° C. The adhesive strength per 25 mm width was measured.
The higher the value, the higher the adhesive strength. Although the target strength varies depending on the adherend, the adhesive strength is generally used in the range of 1 to 400 g / 25 mm. If the adhesive strength is too low, bonding to the adherend cannot be performed. If the adhesive strength is too high, it cannot be easily peeled off from the adherend .
(11) Exterior ( peeling treatment layer ) -Adhesive delamination property: Usually, the surface protective film is wound around a paper tube in a form in which the exterior ( peeling treatment layer ) and the adhesive layer are in contact with each other. used. As an evaluation of unwinding property, the molded film is rolled up in a form in which the outer layer ( peeling layer ) and the adhesive layer are in contact with a 3-inch paper tube, attached to the unwinding machine, and wrinkled, sagging, etc. It was visually confirmed whether or not it could be smoothly fed out, and ○ that was able to be smoothly fed out was marked with ○, and that that could not be smoothly fed out was marked with ×.
(12) Delamination (Punching impact strength): Using a “puncture tester” tester manufactured by Toyo Seiki, punching was performed using a 1/2 inch hemispherical head, visually confirmed, and those that did not peel Those with peeling were marked with x.

2. Resin material (1) Propylene-based resin As propylene-based resin, the propylene-based resin (PP-1 to 4) obtained in Production Examples 1 to 4 using a metallocene catalyst, a propylene / ethylene random copolymer (Wintech WFX4) using a metallocene catalyst (Nippon Polypro Co., Ltd.), Wintech WFW4 (Nihon Polypro Co., Ltd.), Wintech WFX6 (Nihon Polypro Co., Ltd.), Wintech WSX02 (Nihon Polypro Co., Ltd.)), propylene by Ziegler catalyst・ Ethylene-butene random copolymer (Novatech PP FX4G (manufactured by Nippon Polypro Co., Ltd.), Novatec PP FW4B (manufactured by Nippon Polypro Co., Ltd.)), Ziegler catalyst propylene / ethylene random copolymer (Novatech PP FX3A (Japan) Polypro Corporation)), Ziegler catalyst A propylene homopolymer (Novatech PP FB3C (manufactured by Nippon Polypro Co., Ltd.)) was used. Table 1 shows the physical properties.

(Production Example 1)
(I) Synthesis of metallocene compound Synthesis of (r) -dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (4-chlorophenyl) -4H-azurenyl}] hafnium is disclosed in JP-A-11-240909. This was performed according to the method described in the publication.
(Ii) Preparation of chemically treated ion-exchange layered silicate Slowly add 3.75 liters of distilled water followed by 2.5 kg of concentrated sulfuric acid (96%) to a 10-liter glass separable flask equipped with a stirring blade did. At 50 ° C., 1 kg of montmorillonite (Mizusawa Chemical Co., Ltd. Benclay SL) was further dispersed, the temperature was raised to 90 ° C., and the temperature was maintained for 6.5 hours. After cooling to 50 ° C., the slurry was filtered under reduced pressure to recover the cake. 7 liters of distilled water was added to this cake, and after reslurry, it was filtered. This washing operation was performed until the pH of the washing liquid (filtrate) exceeded 3.5.
The collected cake was dried at 110 ° C. overnight under a nitrogen atmosphere. The weight after drying was 705 g of chemically treated silicate.
The silicate previously chemically treated was further dried with a kiln dryer. The specifications and conditions of the dryer are as follows.
Rotating cylinder: cylindrical shape, inner diameter 50 mm, humidification zone 550 mm (electric furnace), rotation speed with lifting blade: 2 rpm, tilt angle: 20/520, silicate feed rate: 2.5 g / min, gas flow rate: nitrogen, 96 liters / hour, countercurrent drying temperature: 200 ° C. (powder temperature)
(Iii) Preparation of solid catalyst In a metal reactor equipped with a stirrer with an internal volume of 13 liters, 0.20 kg of the dried silicate obtained above and 0.74 liters of Nitsubishi Mitsubishi Corporation heptane (hereinafter referred to as heptane). In addition, 1.26 liters of a heptane solution of trinormal octyl aluminum (0.04M) was added, and the system temperature was maintained at 25 ° C. After the reaction for 1 hour, it was thoroughly washed with heptane to prepare 2.0 liters of a silicate slurry.
0.80 liters of heptane was added to 2.44 g (3.30 mmol) of (r) -dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (4-chlorophenyl) -4H-azulenyl}] hafnium, A mixture obtained by adding 33.1 ml of a heptane solution of triisobutylaluminum (0.71 M) and reacting at room temperature for 1 hour is added to the silicate slurry, and after stirring for 1 hour, 5.0 heptane is added and 5.0 liter is added. Adjusted.
Subsequently, at a temperature of 40 ° C., propylene was supplied at a rate of 100 g / hour, and prepolymerization was performed for 4 hours. Further polymerization was carried out for 1 hour.
After completion of the prepolymerization, the residual monomer was purged, and the catalyst was thoroughly washed with heptane. Subsequently, 0.17 L of heptane solution of triisobutylaluminum was added, followed by drying under reduced pressure at 45 ° C. By this operation, 0.60 kg of a dried prepolymerized catalyst was obtained.
(Iv) Polymerization After the inside of a stirring autoclave having an internal volume of 200 liters was sufficiently substituted with propylene, 24 g of triisobutylaluminum and 0.4 g of hydrogen were added, and 45 kg of sufficiently dehydrated liquefied propylene was introduced thereto. The temperature was raised to 40 ° C. Thereafter, 1.6 g of the prepolymerized catalyst was injected with argon, the temperature was raised to 75 ° C. over 40 minutes, and polymerization was performed for 3 hours. Thereafter, 100 ml of ethanol was injected to stop the reaction, the remaining gas was purged, and the product was dried to obtain a propylene homopolymer (PP1).
(Vi) Propylene-based resin Tetrakis [methylene-3- (3 ′, 5′-di-t-butyl-4-hydroxyphenyl) as an antioxidant with respect to 100 parts by weight of the obtained propylene homopolymer (PP1) Propionate] methane (manufactured by Ciba Specialty Chemicals, trade name Irganox 1010) 0.05 parts by weight, tris- (2,4-di-t-butylphenyl) phosphite (manufactured by Ciba Specialty Chemicals, 0.05 parts by weight of trade name Irgafos 168) was mixed, mixed at 750 rpm for 1 minute with a Henschel mixer, then pelletized at an extrusion temperature of 230 ° C. using a 50 mmφ single screw extruder, and propylene resin (PP-1) Got.

(Production Example 2)
After thoroughly replacing the inside of the stirring autoclave with an internal volume of 200 liters with propylene, 500 ml (0.12 mol) of triisobutylaluminum / n-hexane solution, 0.8 NL of hydrogen, and 1.94 kg of ethylene were added. 45 kg of sufficiently dehydrated liquefied propylene was introduced. The temperature was raised to 40 ° C., and 2.8 g of the prepolymerized catalyst prepared in Production Example 1 was injected with argon. The temperature was raised to 62 ° C. over 40 minutes, and polymerization was carried out for 2 hours under these conditions. Thereafter, 100 ml of ethanol was injected to stop the reaction, the remaining gas was purged, and the product was dried to obtain a propylene / ethylene random copolymer (PP2). The resulting propylene / ethylene random copolymer (PP2) was pelletized by the same additive formulation and method as in Production Example 1 to obtain a propylene-based resin (PP-2).

(Production Example 3)
After thoroughly replacing the inside of the stirred autoclave with an internal volume of 200 liters with propylene, 500 ml (0.12 mol) of triisobutylaluminum / n-hexane solution, 8.0 NL of hydrogen, and 1.92 kg of ethylene were added. 45 kg of sufficiently dehydrated liquefied propylene was introduced. The temperature was raised to 40 ° C., and 1.6 g of the prepolymerized catalyst prepared in Production Example 1 was injected with argon. The temperature was raised to 62 ° C. over 40 minutes, and polymerization was carried out for 2 hours under these conditions. During this time, hydrogen was introduced at a constant speed of 0.48 g / hr. Thereafter, 100 ml of ethanol was injected to stop the reaction, the remaining gas was purged, and the product was dried to obtain a propylene / ethylene random copolymer (PP3). The resulting propylene / ethylene random copolymer (PP3) was pelletized by the same additive formulation and method as in Production Example 1 to obtain a propylene-based resin (PP-3).

(Production Example 4)
After thoroughly replacing the inside of the stirred autoclave with an internal volume of 200 liters with propylene, 500 ml (0.12 mol) of triisobutylaluminum / n-hexane solution, 2.3 NL of hydrogen, and 1.94 kg of ethylene were added. 45 kg of sufficiently dehydrated liquefied propylene was introduced. The temperature was raised to 40 ° C., and 2.2 g of the prepolymerized catalyst prepared in Production Example 1 was injected with argon. The temperature was raised to 62 ° C. over 40 minutes, and polymerization was carried out for 2 hours under these conditions. Thereafter, 100 ml of ethanol was injected to stop the reaction, the remaining gas was purged, and the product was dried to obtain a propylene / ethylene random copolymer (PP4). The resulting propylene / ethylene random copolymer (PP4) was pelletized by the same additive formulation and method as in Production Example 1 to obtain a propylene-based resin (PP-4).

(2) Ethylene / α-olefin copolymer and polyethylene As the ethylene / α-olefin copolymer and polyethylene, the ethylene / α-olefin random copolymer (PE-1) obtained in Production Examples 5 to 6 using a metallocene catalyst was used. ~ 2) and high-pressure method low-density polyethylene Novatec LD LF240 (manufactured by Nippon Polyethylene Co., Ltd.) by high-pressure radical polymerization method were used. Table 2 shows the physical properties.

(Production Example 5)
The catalyst was prepared by the method described in JP-T-7-508545. That is, to the complex dimethylsilylene bis (4,5,6,7-tetrahydroindenyl) hafnium dimethyl 2.0 mmol, tripentafluorophenyl boron was added in an equimolar amount to the above complex, and diluted to 10 liters with toluene. A catalyst solution was prepared.
A stirred autoclave type continuous reactor having an internal volume of 1.5 liters was maintained at a pressure of 130 MPa, and a mixture of ethylene and 1-hexene was 40 kg / hour so that the composition of 1-hexene was 72% by weight. Continuously. Further, the catalyst supply amount was adjusted so that the polymerization temperature was maintained at 122 ° C. The polymer production per hour was about 2.1 kg. After completion of the reaction, an ethylene / 1-hexene copolymer (PE1) was obtained. The obtained ethylene / 1-hexene copolymer (PE1) was pelletized at an extrusion temperature of 230 ° C. using a 50 mmφ single screw extruder to obtain an adhesive resin (PE-1).

(Production Example 6)
In Production Example 5, the conditions were changed so that the polymerization temperature was 144 ° C., and the composition of 1-hexene in the mixture of ethylene and 1-hexene was 63% by weight, and an ethylene / 1-hexene copolymer (PE2 ) The obtained ethylene / 1-hexene copolymer (PE2) was pelletized at an extrusion temperature of 230 ° C. using a 50 mmφ single screw extruder to obtain an adhesive resin (PE-2).

(3) Ethylene / vinyl acetate copolymer As an ethylene / vinyl acetate copolymer (EVA), Novatec EVA LV342 (Nippon Polyethylene Co., Ltd.) having a vinyl acetate content (VAC) of 10% obtained by high-pressure radical polymerization. Made). Table 2 shows the physical properties.

Example 1
As a propylene-based resin polymerized using a metallocene catalyst, the lip clearance of the T-die is obtained using a T-die method film manufacturing apparatus using WFX6 as a raw material and having an extruder with a diameter of 35 mmφ, a width 330 mmT die, an air knife and a cooling roll. The film was formed at a film take-off speed of 10 m / min under the conditions of 0.8 mm, a setting temperature of the cylinder of the extruder of 230 ° C., and a cooling roll temperature of 35 ° C. to obtain a film having a film thickness of 40 μm. The characteristic of the propylene-type resin film (base material layer) was evaluated from the obtained film. The results are shown in Table 3.

(Example 2)
A film was formed and evaluated in the same manner as in Example 1 except that WFX6 used in Example 1 was replaced with WFX4. The results are shown in Table 3.

(Example 3)
A film was formed and evaluated in the same manner as in Example 1 except that WFX6 used in Example 1 was replaced with WSX02. The results are shown in Table 3.

Example 4
A film was formed and evaluated in the same manner as in Example 1 except that WFX6 used in Example 1 was replaced with WFW4. The results are shown in Table 3.

(Example 5)
A film was formed and evaluated in the same manner as in Example 1 except that WFX6 used in Example 1 was replaced with the propylene-based resin (PP-1) obtained in Production Example 1. The results are shown in Table 3.

(Comparative Example 1)
A film was formed and evaluated in the same manner as in Example 1 except that WFX6 used in Example 1 was replaced with FX4G. The results are shown in Table 3.

(Comparative Example 2)
A film was formed and evaluated in the same manner as in Example 1 except that WFX6 used in Example 1 was replaced with FX3A. The results are shown in Table 3.

(Comparative Example 3)
A film was formed and evaluated in the same manner as in Example 1 except that WFX6 used in Example 1 was replaced with FW4B. The results are shown in Table 3.

(Comparative Example 4)
WFX6 used in Example 1 was formed and evaluated in the same manner as in Example 1 except that FB3C was replaced. The results are shown in Table 3.

(Comparative Example 5)
Film formation was attempted in the same manner as in Example 1 except that WFX6 used in Example 1 was replaced with the propylene-based resin (PP-2) obtained in Production Example 2. There wasn't.

(Comparative Example 6)
Film formation was tried in the same manner as in Example 1 except that WFX6 used in Example 1 was replaced with the propylene-based resin (PP-3) obtained in Production Example 3, but the film thickness varied. Film formation was not possible.

(Comparative Example 7)
A film was formed and evaluated in the same manner as in Example 1 except that WFX6 used in Example 1 was replaced with the propylene-based resin (PP-4) obtained in Production Example 4. The results are shown in Table 3.

  From the results in Table 3, it can be seen that the propylene-based resin used for the surface protective film of the present invention is excellent in transparency and rigidity and has few fish eyes (Examples 1 to 5). On the other hand, a propylene / ethylene random copolymer having MFR and Mw / Mn obtained using a metallocene catalyst outside the scope of the present invention cannot produce a film or has too many fish eyes (Comparative Examples 5 to 7). ), The propylene homopolymer, propylene / ethylene random copolymer, and propylene / ethylene / butene random copolymer obtained with the Ziegler catalyst have too many fish eyes (Comparative Examples 1 to 4).

(Example 6)
Using a T-die two-layer coextrusion film production apparatus equipped with a 35 mmφ extruder, a 20 mmφ extruder, a 300 mm wide T die, an air knife and a cooling roll, a propylene resin as a raw material for a substrate layer in a 35 mmφ extruder (WFX4) is used, PE-1 is used as a raw material for the adhesive layer in a 20 mmφ extruder, the lip clearance of the T die is 0.8 mm, the set temperature of the cylinder of the extruder is 230 ° C., and the cooling roll temperature is 35 Under the condition of ° C., a protective film composed of two unstretched films was formed by co-extrusion so that the substrate layer thickness was 40 μm and the adhesive layer thickness was 10 μm at a film forming take-up speed of 10 m / min. Table 4 shows the evaluation results of the obtained surface protective film.

(Example 7)
Example 6 except that WFX4 was used as the propylene-based resin used for the base material layer, and a mixture of PE-1: 80% by weight and PE-4: 20% by weight was used as the material for the pressure-sensitive adhesive layer used for the pressure-sensitive adhesive layer. A surface protective film was molded under the same conditions. Table 4 shows the evaluation results of the obtained surface protective film.

(Example 8)
A surface protective film was molded under the same conditions as in Example 6 except that WFW4 was used as the propylene-based resin used for the base material layer and PE-1 was used as the raw material for the pressure-sensitive adhesive layer used for the pressure-sensitive adhesive layer. Table 4 shows the evaluation results of the obtained surface protective film.

Example 9
A surface protective film was molded under the same conditions as in Example 6 except that WFX4 was used as the propylene-based resin used for the base material layer and PE-2 was used as the raw material for the pressure-sensitive adhesive layer used for the pressure-sensitive adhesive layer. Table 4 shows the evaluation results of the obtained surface protective film.

(Comparative Example 8)
A surface protective film was used under the same conditions as in Example 6 except that FX4G outside the scope of the present invention was used as the propylene-based resin used in the base material layer, and PE-1 was used as the raw material for the adhesive layer used in the adhesive layer. Molded. Table 4 shows the evaluation results of the obtained surface protective film.

(Comparative Example 9)
A surface protective film was used under the same conditions as in Example 6 except that FW4B outside the scope of the present invention was used as the propylene-based resin used for the base material layer, and PE-1 was used as the material for the pressure-sensitive adhesive layer used for the pressure-sensitive adhesive layer. Molded. Table 4 shows the evaluation results of the obtained surface protective film.

(Example 10 (reference example) )
A surface protective film was molded under the same conditions as in Example 6 except that WFX4 was used as the propylene-based resin used for the base material layer and LF240 was used for the pressure-sensitive adhesive layer. Table 4 shows the evaluation results of the obtained surface protective film.

(Example 11 (reference example) )
A surface protective film was molded under the same conditions as in Example 6 except that WFX4 was used as the propylene-based resin used for the base material layer and LV342 was used for the pressure-sensitive adhesive layer. Table 4 shows the evaluation results of the obtained surface protective film.

  From the results of Table 4, it can be seen that the surface protective film of the present invention has transparency characteristics, and in particular, the surface obtained by using an ethylene / α-olefin copolymer having specific physical properties for the pressure-sensitive adhesive layer. The protective film is excellent in transparency and rigidity, and can impart the desired adhesive strength by adjusting the density of the adhesive layer. Further, the protective film is excellent in unwinding property and has little or no delamination. (Examples 6 to 11). On the other hand, the film for surface protection using the propylene / ethylene / butene random copolymer obtained by the Ziegler catalyst is inferior in transparency (Comparative Examples 8 to 9).

  The film for surface protection of the present invention is made of a specific propylene resin, because the crystallinity distribution of the resin is narrow, the amount of low crystalline components eluted is small, the molecular weight distribution is narrow, and the high molecular weight component is small. There is very little unmelted fish eye during film forming. For this reason, even if a surface protection film is affixed on a to-be-protected object and stored in a stacked manner, the to-be-protected object does not dent. Therefore, it can be suitably used as a film for protecting the surface of building members such as a synthetic resin plate, a decorative plate, a metal plate, and a glass plate, and as a surface protecting film for liquid crystal display components such as a polarizing plate and a retardation plate.

Claims (5)

In the surface protective film in which the pressure-sensitive adhesive layer is formed on one surface of the base material layer made of propylene-based resin,
The pressure-sensitive adhesive layer is polymerized using a metallocene catalyst, the density is 0.860 to 0.918 g / cm ^3, and the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is 3. A layer mainly composed of an ethylene / α-olefin copolymer of 5 or less,
The propylene-based resin is a propylene homopolymer or a propylene / α-olefin random copolymer polymerized using a metallocene catalyst and having the following properties (A1) to (A4): Protective film.
(A1) Melt flow rate (MFR: 230 ° C., 21.18 N load) is 1 to 50 g / 10 minutes (A2) Melting peak temperature (Tmp) by differential thermal scanning calorimeter (DSC) is 120 to 170 ° C.
(A3) The ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) determined by gel permeation chromatography (GPC) is 1.5 to 3.5.
(A4) Soluble content (S ₄₀ ) of 40 ° C. or less measured by temperature rising elution fractionation (TREF) method is 10% by weight or less The film for surface protection according to claim 1 , wherein the propylene-based resin further has the following property (A5).
(A5) The range (T ₁₀₀ -T ₂₀ ) of the temperature (T ₁₀₀ ) at the end of elution by 100 wt% from the temperature (T ₂₀ ) at the elution of 20 wt% by the temperature rising elution fractionation (TREF) method is 30 ° C. Less than The surface protective film according to claim 1 or 2 , wherein a pressure-sensitive adhesive layer is formed on one surface of the base material layer, and a release treatment layer is formed on the other surface. It is used for the surface protection of a building member, The film for surface protection of any one of Claims 1-3 characterized by the above-mentioned. It is used for the surface protection of the structural member of a liquid crystal display, The film for surface protection of any one of Claims 1-3 characterized by the above-mentioned.