JP2009113481A - Surface protection film and its production process - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a propylene based resin surface protection film and its production process, wherein the surface protection film is suitable for surface protection of building and liquid crystal display components due to its characteristics of making less fish-eye and further scarce small fish-eye. <P>SOLUTION: The surface protection film is composed of an adhesive layer laminated on a substrate layer comprising a propylene resin (A) which is either a propylene homopolymer polymerized using a metallocene catalyst and has following characteristics (A1)-(A4), or a propylene-α-olefine random copolymer; wherein the substrate layer is formed by feeding the propylene resin (A) to a die through a filter of 1-60 μm diameter after melt kneading with an extruder and extruding from the die. The characteristics (A1)-(A4) are: (A1) melt flow rate (MFR at 230°C, 21.18 N load) being 1-50 g/10 minutes; (A2) fusion peak temperature (Tmp) by differential scanning calorimeter (DSC) being 120-170°C; (A3) ratio (Mw/Mn) of weight average molecular weight (Mw) and number average molecular weight (Mn) as measured by gel permeation chromatography (GPC) being 1.5-3.5; and (A4) soluble portion at 40°C or lower (S<SB>40</SB>) as measured by temperature rising elution fractionation (TREF) method being 10 wt.% or less. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a film for surface protection and a method for producing the same, and more specifically, from the characteristics that there are few fish eyes and there are also very few fine-sized fish eyes, synthetic resin plates, decorative plates, metal plates, glass plates, etc. The present invention relates to a surface protective film made of a propylene-based resin suitable for protecting the surface of a building member or for protecting a surface of a liquid crystal display component such as a polarizing plate or a retardation plate, and a method for producing the same.

  In recent years, surface protection films have been applied to building materials such as synthetic resin plates and liquid crystal display parts of optical equipment members in order to prevent scratches and contamination on the surface during processing, transportation, and transportation. Or it is common to peel off and use the surface protection film which concerns after transportation conveyance.

Conventionally, as a surface protective film, there is a surface protective film mainly composed of an ethylene-based resin.
For example, Patent Document 1 discloses a surface protective film in which an adhesive layer is formed on one side of a base film made of a specific ethylene-based resin, and the surface protective film does not generate fish eyes, It is also described that it is suitable for a constituent member of a liquid crystal display such as a deflection plate or a retardation plate.

  Patent Document 2 discloses a polyethylene resin layer comprising 50 to 90% by weight of a specific low density polyethylene and 10 to 50% by weight of a high density polyethylene having a specific molecular weight and distribution, and an ethylene-unsaturated ester copolymer. A laminated film in which an adhesive resin layer made of a polymer is coextruded is disclosed, and the laminated film is applied to a metal plate to protect the surface from dirt and damage, and further to punchability during punching. It is described that it is excellent.

  However, the surface protective film obtained from a resin containing polyethylene as the main component stays in the dead space inside the extruder or die when the film is formed for a long time. Since it deteriorates and crosslinks, gelation occurs, and many unmelted fine lumps (hereinafter referred to as fish eyes) are generated in the film. Therefore, such a film was attached to an object to be protected. After that, when stacked and stored as it is, the existence of fish eyes causes dents to be protected. As a result, for example, when a polarizing plate or a retardation plate used in a liquid crystal display material is used as an object to be protected, and the surface protective film is used for the object, the object to be protected is dented, and the image is distorted. A problem that is not applicable is happening.

On the other hand, from the viewpoint that gelation due to crosslinking deterioration hardly occurs, use of a propylene-based resin instead of a polyethylene-based resin as a material for the surface protection film has been studied.
For example, Patent Document 3 discloses a polypropylene having a MFR and chlorine content within a specific range, in particular, a polypropylene having a chlorine content of 5 ppm by weight or less obtained by washing polypropylene powder with a mixed solvent of isopropanol and heptane after polymerization. A surface protective film used for a base material is disclosed, and when such a polypropylene is used, heat resistance, scratch resistance and rigidity, which are weak points of polyethylene, can be overcome and used for a thin display panel. When a protective film made of polypropylene is used for a transparent electrode or electromagnetic wave shielding film using a resin film provided with a thin metal film layer, it is effective to cause point defects in the metal thin film layer due to the influence of chlorine ions. It is disclosed that it can be prevented.

  Certainly, when a propylene-based resin is used, the generated fish eye can be reduced as compared with a polyethylene-based resin because gelation due to cross-linking degradation hardly occurs. However, simply by adjusting the MFR and chlorine content, a high-spec surface protection film called 10 / m2 or less fish eye, which is necessary for the use of liquid crystal display components such as polarizing plates and retardation plates, is used. The current situation is that it cannot be obtained at all.

  A method is also known in which gel-like materials and foreign matters mixed in the molten resin are removed with a sintered filter. Certainly, by using this method, it is possible to easily remove gel-like substances and foreign matters. However, if it is going to remove even fine fish eyes, it is necessary to use a sintered filter with a small filtration diameter, but the passage resistance of the filter due to the molten resin, that is, the pressure loss becomes extremely large, making the production of the film difficult. There were many things.

  As a method for solving such a problem, Patent Document 4 discloses a method in which a polyethylene resin containing a gel-like material and foreign matter is pumped through a sintered body filter by a gear pump to remove the gel-like material and foreign matter. Is disclosed. However, when a gear pump is used, resin often stays in the gear pump and deteriorates.

Therefore, as a method for solving such a problem without using a gear pump, Patent Document 5 uses a specific ethylene-α-olefin copolymer to reduce the resin pressure and use a gear pump. A method for producing a film with little fish eye through a sintered filter is described. However, since the resin used is an ethylene-based copolymer, it cannot be said to be sufficient in terms of heat resistance, scratch resistance and rigidity required for the film, and it can satisfy the suppression of the generation of fish eyes. It wasn't.
Under such circumstances, there has been a demand for the early development of a surface protection film with extremely few fish eyes, which eliminates the problems of conventional surface protection films using polypropylene resins.
JP-A-9-111208 JP 54-133578 A JP 2006-282761 A JP-A-8-103952 JP 2005-271420 A

  In view of the problems of the prior art, the object of the present invention is to reduce the number of fish eyes, and also to have very few fine-sized fish eyes, so that it can be used for building materials such as synthetic resin plates, decorative plates, metal plates, and glass plates. An object of the present invention is to provide a surface protective film made of a propylene-based resin suitable for surface protection or for surface protection of liquid crystal display components such as polarizing plates and retardation plates, and a method for producing the same.

  As a result of intensive studies to solve the above-mentioned problems, the present inventor has melt-kneaded a propylene-based resin having specific physical properties with an extruder, and then supplied it to a die through a filter having a specific filtration diameter, and pushed from the die. When the surface protective film in which the adhesive layer is laminated on the base material layer formed by taking out is prepared, since there are extremely few fish eyes caused by unmelted resin, the surface protective film, in particular, a small number This fish eye was found to be suitable for a film for surface protection which causes extremely inconvenience as a polarizing plate or a retardation plate used as a liquid crystal display material, and the present invention was completed.

That is, according to the first invention of the present invention, it is composed of a propylene homopolymer or a propylene / α-olefin random copolymer polymerized using a metallocene catalyst and having the following properties (A1) to (A4). A surface protecting film in which an adhesive layer is laminated on a base material layer made of a propylene-based resin (A),
The base material layer is formed by melting and kneading the propylene-based resin (A) with an extruder, then supplying the die through a filter having a filtration diameter of 1 to 60 μm, and extruding from the die. A surface protecting 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) measured by a differential thermal scanning calorimeter (DSC) is 120 to 170 (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 the temperature rising elution fractionation (TREF) method is 10% by weight or less.

According to the second invention of the present invention, in the first invention, the propylene-based resin (A) is 100 from the temperature (T ₂₀ ) when 20% by weight is eluted by the temperature rising elution fractionation (TREF) method. A surface protective film having a characteristic that the temperature (T ₁₀₀ ) width (T ₁₀₀ -T ₂₀ ) at the end of elution by weight% is 30 ° C. or less is provided.

  According to a third aspect of the present invention, there is provided the surface protecting film according to the first or second aspect, wherein the catalyst residue of the propylene-based resin (A) is 50 ppm or less.

  According to a fourth invention of the present invention, in any one of the first to third inventions, a release treatment layer is laminated on the side opposite to the adhesive layer on the base material layer. A surface protecting film is provided.

  According to a fifth invention of the present invention, in any one of the first to fourth inventions, the adhesive layer is obtained by melting and kneading the adhesive with an extruder and then passing it through a filter having a filtration diameter of 1 to 60 μm. The film for surface protection is provided by being fed to and extruded from the die.

  According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the release treatment layer is a filter having a filtration diameter of 1 to 60 μm after melt-kneading the release treatment agent with an extruder. A film for surface protection is provided which is formed by feeding to a die through and extruding from the die.

According to a seventh aspect of the present invention, there is provided a surface protecting film according to any one of the first to sixth aspects, wherein the number of fish eyes is 10 / m ² or less.

  Moreover, according to the eighth invention of the present invention, in any one of the first to seventh inventions, there is provided a surface protecting film which is used for protecting a surface of a building member.

  According to a ninth aspect of the present invention, there is provided a surface protective film characterized in that, in any one of the first to seventh aspects, the surface protective film is used for protecting a surface of a constituent member of a liquid crystal display. .

According to the tenth aspect of the present invention, the propylene homopolymer or the propylene / α-olefin random copolymer is polymerized using a metallocene catalyst and has the following properties (A1) to (A4). A method for producing a surface protective film in which an adhesive layer is laminated on a base material layer made of a propylene-based resin (A),
The base layer is formed by melting and kneading the propylene-based resin (A) with an extruder, then supplying the die through a filter having a filtration diameter of 1 to 60 μm, and extruding from the die. The manufacturing method of the film for surface protection which concerns on either invention of -9 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) measured by a differential thermal scanning calorimeter (DSC) is 120 to 170 (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 the temperature rising elution fractionation (TREF) method is 10% by weight or less.

  Since the film for surface protection of the present invention has a base material layer obtained by passing a specific propylene-based resin (A) through a filter having a filtration diameter of 1 to 60 μm, it can be produced without using a gear pump. Since the fisheye caused by the molten resin is extremely small, it is extremely inconvenient as a polarizing plate or retardation plate used as a liquid crystal display material even with a surface protecting film, especially a small number of fish eyes. It is suitable for surface protection films that cause fish eyes to dent when they are stacked and stored on the object to be protected. Furthermore, it is widely used for synthetic resin plates, decorative plates, metal plates. It can also be used as a surface protecting film having excellent performance for building members such as glass plates.

  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 having characteristics (A1) to (A4) and, if necessary, characteristics (A5) to (A6), or propylene / α- It is a film for surface protection which consists of propylene-type resin (A) which is an olefin random copolymer. Hereinafter, the component of each layer of the surface protective film of the present invention, the production method of the surface protective film, and the like will be described 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 (A) as described in detail below.
As the propylene-based resin (A), a propylene homopolymer or a random copolymer of propylene and an α-olefin can be used. Here, as an alpha olefin used as a random copolymerization component, ethylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene, etc. are mentioned.

  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 (A) used in the present invention has the following characteristics (A1) to (A4), and further has characteristics (A5) to (A6) as necessary.

(A1) Melt flow rate The propylene-based resin (A) used in the present invention has a melt flow rate value (hereinafter referred to as MFR) of 1 to 50 g / 10 minutes, preferably 2 to 30 g / 10 minutes. Preferably it is 5 to 20 g / 10 min, most preferably 7 to 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. If the MFR exceeds 50 g / 10 minutes, the thickness accuracy at the time of film formation tends to deteriorate, which is not preferable.
The measurement of MFR (unit: g / 10 minutes) employed in the present invention was performed at 230 ° C. and a load of 21.18 N in accordance with JIS K-7210-1995.

(A2) Melting peak temperature The propylene-based resin (A) used in the present invention has a melting peak temperature (hereinafter sometimes referred to as Tmp) of 120 ° C to 170 ° C, preferably 120 ° C to 165 ° C. Preferably they are 120 to 160 degreeC, Most preferably, it is 120 to 150 degreeC.
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 non-adhering body. When the melting peak temperature is higher than 170 ° C., the impact strength is inferior, and tearing may occur when the surface protective 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 degreeC) measurement employ | adopted in this invention took the sample amount 5.0mg using the differential scanning calorimeter (Seiko DSC), and hold | maintained at 200 degreeC for 5 minutes. Then, the melting peak temperature (Tmp) when crystallizing to 40 ° C. at a temperature lowering speed of 10 ° C./min and further melting at a temperature rising speed of 10 ° C./min was measured.

(A3) Ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) The propylene-based resin (A) used in the present invention has a weight average molecular weight (Mw) / number average molecular weight (Mn) (hereinafter referred to as (Mw ) / (Mn))) is 1.5 to 3.5, preferably 1.7 to 3.2, more preferably 2.0 to 3.0, most preferably 2.3. 2.8. When the value of (Mw) / (Mn) is less than 1.5, the molten resin viscosity becomes high, the melt fluidity becomes poor, and extrusion molding becomes difficult. On the other hand, if the value of (Mw) / (Mn) exceeds 3.5, the abundance ratio of molecules having a low molecular weight and molecules having a high molecular weight increases, and the high molecular weight component is not melted when forming a surface protective film. Then, after being affixed to the object to be protected, if the product is stacked and stored as it is, a dent will be generated in the object to be protected.
(Mw / Mn) can be adjusted by changing the polymerization conditions (polymerization temperature, polymerization pressure) during production and the type of catalyst used.

In addition, the measurement of (Mw) / (Mn) employ | adopted in this invention was performed by the 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 propylene-based resin (A) used in the present invention has a soluble content (S ₄₀ ) of 40 ° C. or less measured by a temperature rising elution fractionation (TREF) method of 10% by weight or less, preferably 8% by weight or less, more preferably Is 6% by weight or less, 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 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 propylene-based resin (A) used in the present invention (T _100- T ₂₀ ) is preferably 30 ° C. or less, more preferably 25 ° C. or less, further preferably 20 ° C. or less, and most preferably 15 ° C. or less. 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 hot elution fractionation (TREF) method employed in the present invention is a 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 allowed to flow through the column at a flow rate of 1 mL / min, and components dissolved in the orthodichlorobenzene at 40 ° C. 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

(A6) Catalyst residue The catalyst residue of the propylene-based resin (A) used in the present invention is preferably 50 ppm or less, more preferably 40 ppm or less, further preferably 30 ppm or less, and particularly preferably 20 ppm or less. The catalyst residue is a residual catalyst main component of the propylene-based resin (A), and is the sum of aluminum (Al) residue, titanium (Ti) residue, chlorine (Cl) residue, magnesium (Mg) residue, and silicon (Si) residue. Say. When the catalyst residue exceeds 60 ppm, the filter is clogged and the resin pressure is suddenly increased. In some cases, the filter is damaged.
The catalyst residue is a residue derived from the catalyst used for the polymerization to the end. When an additive is added, the additive-derived aluminum (Al), titanium (Ti), chlorine (Cl), magnesium (Mg) Needless to say, silicon (Si) is not included in the catalyst residue defined in the present invention. Therefore, when analyzing from a propylene-type resin, it cannot be overemphasized that the residue derived from an additive is remove | excluded.

The catalyst residue employed in the present invention was measured by the following method.
About 2 g of the propylene-based resin (A) powder sample was pressed using a mold at a temperature of 190 ° C. and a pressure of 50 kg / cm ² G to produce a pressed piece having a thickness of 1.5 (mm). In the pressing, the preheating time was 30 seconds and the pressing time was 30 seconds. The obtained press piece was analyzed using an X-ray fluorescence spectrometer, and the catalyst residue in the sample was quantified. The X-ray fluorescence spectrometer is calibrated using standard samples of components (aluminum (Al), titanium (Ti), chlorine (Cl), magnesium (Mg), silicon (Si))) separately prepared. It was.

Such a propylene resin is required to be polymerized using a metallocene catalyst.
The propylene homopolymer polymerized by the metallocene catalyst or the propylene / α-olefin random copolymer 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-3-163088, JP-A-4-300787, 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 polyolefins, styrene / divinylbenzene copolymers, olefin / acrylic acid copolymers, and the like, or mixtures 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 the organoaluminum compound 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. Adhesive layer In the film for surface protection of the present invention, an adhesive layer is formed on one surface of the base material layer made of the propylene-based resin (A).
The pressure-sensitive adhesive layer is not particularly limited as long as it is a known layer, and specifically, 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 copolymers, other than ethylene / vinyl acetate copolymers) and the like are preferably used. The pressure-sensitive adhesive is not limited to its composition. Below, each adhesive is demonstrated in detail.

(1) Rubber-based adhesive The rubber-based adhesive is not particularly limited as long as the effects of the present invention are not impaired, but natural rubber-based adhesives, thermoplastic styrene-diolefin copolymers, etc. Synthetic rubber adhesives and the like. Examples of the natural rubber used in the pressure-sensitive adhesive layer of the present invention include a commercial product name: SMR (manufactured by Kasho Corporation). Moreover, as a thermoplastic styrene-diolefin copolymer used by the adhesive layer of this invention, it is a thermoplastic styrene-diolefin copolymer hydrogenated substance, and has the following characteristic (b1).

(B1) Styrene content [St]
The styrene content [St] of the thermoplastic styrene-diolefin copolymer is not particularly limited, but is 5 to 60% by weight, preferably 10 to 50% by weight, more preferably 20 to 40% by weight. . When the styrene content is within the above range, the transparency is good, the affinity with the propylene resin is good, the dispersibility is good, and the flexibility is small.

  The hydrogenated thermoplastic styrene-diolefin copolymer is obtained by hydrogenating a thermoplastic styrene-diolefin copolymer. The hydrogenated thermoplastic styrene-diolefin copolymer may be a block copolymer or a random copolymer. A block copolymer is preferred.

  In the thermoplastic styrene-diolefin block copolymer hydrogenated product, when the styrene block is represented by STY and the diolefin block hydrogenated product is represented by DEN, STY-DEN, STY-DEN-STY, DEN-STY-DEN- A copolymer having a structure such as STY or STY-DEN-STY-DEN-STY can be given.

  Examples of the monomer constituting the diolefin hydrogenated block include hydrogenated butadiene, isoprene, vinylated polyisoprene, etc., and these may be used alone or in admixture of two or more. it can.

  Specific examples of hydrogenated products of block copolymers of styrene blocks and diolefin blocks include, for example, hydrogenated products of styrene-butadiene block copolymers, hydrogenated products of styrene-isoprene block copolymers, styrene- Examples thereof include hydrogenated products of vinylated polyisoprene block copolymers. These can be used alone or in admixture of two or more.

  The hydrogenated styrene-butadiene block copolymer is sold as “Clayton G” by Clayton Polymer Japan Co., Ltd., and as “Tough Tech” by Asahi Kasei Kogyo Co., Ltd. The hydrogenated styrene-isoprene block copolymer is sold by Kuraray Co., Ltd. under the trade name “Septon”. A hydrogenated product of a styrene-vinylated polyisoprene block copolymer is sold by Kuraray Co., Ltd. under the trade name “Hibler”. You may select and use suitably from these goods groups.

  In the hydrogenated thermoplastic styrene-diolefin random copolymer, examples of the monomer constituting the diolefin hydrogenated block include butadiene, isoprene, vinylated polyisoprene, and the like. , Or a mixture of two or more.

  Specific examples of the hydrogenated random copolymer of styrene and diolefin include hydrogenated styrene butadiene random copolymer, hydrogenated styrene-isoprene random copolymer, and styrene-vinylated polyisoprene random. Examples include hydrogenated products of copolymerization, and these can be used alone or in admixture of two or more.

  A hydrogenated product of a styrene-butadiene random copolymer is sold under the trade name “Dynalon” by JSR Corporation.

  Furthermore, a hydrogenated product of a thermoplastic styrene-diolefin block copolymer and a hydrogenated product of a thermoplastic styrene-diolefin random copolymer can be mixed and used.

  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.

  In addition, when the adhesive layer is laminated by coextrusion molding with an extruder, an adhesive is added to the propylene-ethylene block copolymer used for the base material layer of the present invention in consideration of adhesion to the base material layer. It can mix | blend and can be used as an adhesion layer. When the propylene-ethylene block copolymer used in the present invention is blended with the above-mentioned pressure-sensitive adhesive, the total amount of propylene-ethylene block copolymer and pressure-sensitive adhesive used in the present invention is 100% by weight. -Content of an ethylene block copolymer is 1 to 99 weight%, and content of an adhesive is 99 to 1 weight%. Preferably, the content of the propylene-ethylene block copolymer is 5 to 75% by weight, the content of the pressure-sensitive adhesive is 95 to 25% by weight, and more preferably, the content of the propylene-ethylene block copolymer is 10 to 10%. The content of the pressure-sensitive adhesive is 50 to 90% by weight.

(2) Acrylic pressure-sensitive adhesive The acrylic pressure-sensitive adhesive is not particularly limited as long as the effects of the present invention are not impaired, but contains a (meth) acrylic polymer containing an hydroxyl group as a functional group and an isocyanate-based crosslinking agent. And acrylic pressure sensitive adhesive. An acrylic pressure-sensitive adhesive containing a (meth) acrylic polymer containing a hydroxyl group as a functional group and an isocyanate-based crosslinking agent is used from the balance of transparency, cohesiveness, and peeling properties.

  The (meth) acrylic polymer in the present invention contains an alkyl (meth) acrylate and a hydroxyl group-containing monomer as monomer units. The technique for introducing a hydroxyl group is not particularly limited, but for example, a technique for copolymerizing a hydroxyl group-containing monomer can be easily performed.

  In addition, the (meth) acrylic polymer in the present invention refers to an acrylic polymer and / or a methacrylic polymer, (meth) acrylate refers to an acrylate and / or methacrylate, and an alkyl (meth) acrylate includes Refers to alkyl acrylate and / or alkyl methacrylate.

  Examples of the alkyl (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and the like. Can be given. These compounds may be used alone or in combination of two or more.

  Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl ( (Meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, (4-hydroxymethylcyclohexyl) methyl acrylate, N-methylol (meth) acrylamide, N-hydroxy (meth) acrylamide, Examples include vinyl alcohol, allyl alcohol, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, and diethylene glycol monovinyl ether. These monomers may be used alone or in combination of two or more.

  The hydroxyl group-containing monomer may be used alone or in combination of two or more, but the total content is 1 to 100 parts by weight of the (meth) acrylic polymer. The amount is preferably 10 parts by weight, and more preferably 2 to 6 parts by weight. By copolymerizing the hydroxyl group-containing monomer, a reactive site due to crosslinking or the like is given.

  The (meth) acrylic polymer used in the present invention preferably has a weight average molecular weight of about 300,000 to 2.5 million. When the weight average molecular weight is smaller than 300,000, the adhesive force tends to be generated due to the reduced cohesive force of the pressure-sensitive adhesive composition. A weight average molecular weight means what was obtained by measuring by GPC (gel permeation chromatography).

In addition, the glass transition temperature (Tg) of the (meth) acrylic polymer is preferably 0 ° C. or lower (usually −100 ° C. or higher), preferably −10 ° C. or lower for the reason that the adhesive performance is easily balanced. When the glass transition temperature is higher than 0 ° C., the polymer is difficult to flow and the wetting to the polarizing plate is insufficient, and there is a tendency to cause blisters generated between the polarizing plate and the pressure-sensitive adhesive composition layer of the pressure-sensitive adhesive sheet. is there.
In addition, the glass transition temperature (Tg) of a (meth) acrylic-type polymer can be adjusted in the said range by changing the monomer component and composition ratio to be used suitably.

  Moreover, as other polymerizable monomers other than the above-mentioned monomers, it is possible to use a polymerizable monomer for adjusting the glass transition point and peelability of the (meth) acrylic polymer as long as the effects of the present invention are not impaired. it can.

  Other polymerizable monomers used in (meth) acrylic polymers include, for example, cohesion and heat resistance of sulfonic acid group-containing monomers, phosphate group-containing monomers, cyano group-containing monomers, vinyl ester monomers, aromatic vinyl monomers, etc. It has a functional group that acts as a crosslinking point and improves adhesion, such as an acid-improving component, an acid anhydride group-containing monomer, an amide group-containing monomer, an amino group-containing monomer, an epoxy group-containing monomer, N-acryloylmorpholine, and a vinyl ether monomer. Components can be used as appropriate. These monomer compounds may be used alone or in admixture of two or more.

  Examples of the sulfonic acid group-containing monomer include styrene sulfonic acid, allyl sulfonic acid, 2- (meth) acrylamide-2-methylpropane sulfonic acid, (meth) acrylamide propane sulfonic acid, sulfopropyl (meth) acrylate, (meth And acryloyloxynaphthalene sulfonic acid.

  Examples of the phosphoric acid group-containing monomer include 2-hydroxyethylacryloyl phosphate.

  Examples of the cyano group-containing monomer include acrylonitrile and methacrylonitrile.

  Examples of the vinyl ester monomer include vinyl acetate, vinyl propionate, vinyl laurate, and the like.

  Examples of the aromatic vinyl monomer include styrene, chlorostyrene, chloromethyl styrene, α-methyl styrene, and the like.

  Examples of the acid anhydride group-containing monomer include maleic anhydride and itaconic anhydride.

  Examples of the amide group-containing monomer include acrylamide and diethyl acrylamide.

  Examples of the amino group-containing monomer include N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N- (meth) acryloylmorpholine, and alkylaminoalkyl (meth) acrylate. Examples include esters.

  Examples of the epoxy group-containing monomer include glycidyl (meth) acrylate and allyl glycidyl ether.

  Examples of the vinyl ether monomer include methyl vinyl ether, ethyl vinyl ether, isobutyl vinyl ether, and the like.

  In the present invention, other polymerizable monomers may be used alone or in combination of two or more, but the total content is 100 parts by weight of the (meth) acrylic polymer. On the other hand, it is preferably 0 to 300 parts by weight, and more preferably 0 to 150 parts by weight.

  In addition, the polymerization method in particular of (meth) acrylic-type polymer is not restrict | limited, Well-known polymerization methods, such as solution polymerization, emulsion polymerization, suspension polymerization, and UV polymerization, are employable. Further, the obtained copolymer may be any of a random copolymer, a block copolymer, a graft copolymer, and the like.

  The pressure-sensitive adhesive composition of the present invention is based on the (meth) acrylic polymer as described above.

  In the present invention, an isocyanate crosslinking agent and / or an epoxy crosslinking agent is used as the crosslinking agent. Isocyanate-based crosslinking agents and epoxy-based crosslinking agents are used for imparting adhesion and cohesiveness with the base material layer.

  As the isocyanate-based crosslinking agent, a polyfunctional isocyanate compound is used, and various compounds having two or more isocyanate groups in the molecule are included.

  Examples of the isocyanate compound include lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate, alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate, and isophorone diisocyanate, 2,4-tolylene diisocyanate, Aromatic isocyanates such as 4,4′-diphenylmethane diisocyanate and xylylene diisocyanate, trimethylolpropane / tolylene diisocyanate trimer adduct (trade name Coronate L, manufactured by Nippon Polyurethane Industry Co., Ltd.), trimethylolpropane / hexamethylene Diisocyanate trimer adduct (trade name Coronate HL, manufactured by Nippon Polyurethane Industry Co., Ltd.), isocyanurate of hexamethylene diisocyanate Body (trade name: Coronate HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) and isocyanate adducts and the like. Of these, those having an isocyanurate ring are particularly preferred. For example, polyisocyanate having a long-chain alkylene diol-modified isocyanurate ring (manufactured by Dainippon Ink and Chemicals, Vernock DN-995), isocyanurate of hexamethylene diisocyanate. (Trade name Coronate HX, manufactured by Nippon Polyurethane Industry Co., Ltd.). These compounds may be used alone or in combination.

  The content of the crosslinking agent used in the present invention may be blended to such an extent that it does not affect the physical properties of the adhesive, but is usually contained in an amount of 0.2 to 10 parts by weight with respect to 100 parts by weight of the (meth) acrylic polymer, It is preferable that 0.5-8 weight part is contained, and it is more preferable that 1-6 weight part is contained.

  As an epoxy type crosslinking agent, a polyfunctional epoxy compound is used, and various compounds having two or more epoxy groups in the molecule are included. Typical examples include sorbitol tetraglycidyl ether, trimethylolpropane glycidyl ether, tetraglycidyl-1,3-bisaminomethylcyclohexane, tetraglycidyl-m-xylenediamine, and triglycidyl-p-aminophenol. It is done. Examples of commercially available epoxy crosslinking agents include Tetrad C (manufactured by Mitsubishi Gas Chemical Co., Inc.).

  The number of parts of the epoxy crosslinking agent is generally 1 to 8 parts by weight per 100 parts by weight of the acrylic polymer, although it depends on the amount of acid introduced into the acrylic polymer and the structure of the epoxy crosslinking agent. It is preferable to contain 1-6 weight part.

  For the acrylic pressure-sensitive adhesive, a crosslinking agent (polyamine compound, melamine resin, aziridine derivative, urea resin) other than those exemplified above can also be used as appropriate. These components may be used alone or in combination of two or more.

  Examples of commercially available acrylic pressure-sensitive adhesives include Soken Kagaku Co., Ltd., trade name: AG105, Lexpearl series manufactured by Nippon Polyethylene Co., Ltd., Aklift series manufactured by Sumitomo Chemical Co., Ltd., and the like. Etc.

(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. When the density is less than 0.85 g / cm ³ , the adhesive strength becomes too strong, and adhesive residue is generated on the adherend. When the density exceeds 0.89 g / cm ³ , the adhesive strength necessary for the adhesive layer is not expressed. 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 Company, VERSIFY series manufactured by The Dow Chemical Company, Notio manufactured by Mitsui Chemicals, Inc. The Tuffmer series 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%. It is. 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 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. In addition, the melt flow rate of the said ethylene vinyl acetate copolymer (EVA) is measured based on JIS-K6922-2: 1997 appendix (190 degreeC, 21.18N 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 random copolymer is preferably used and copolymerized with ethylene. As the α-olefin, an α-olefin having 3 to 20 carbon atoms is preferable, 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. Those having an ethylene content of less than 50% by weight are inferior in adhesive strength because the adhesive strength is too weak. The content of α-olefin is appropriately adjusted according to the required density.
The melt flow rate (MFR: 190 ° C., 21.18 N load) of the ethylene polymer is 0.1 to 50 g / 10 minutes, preferably 1 to 30 g / 10 minutes, more preferably 2 to 15 g / 10. Minutes. If it is less than 0.1 g / 10 min, the extrusion characteristics are likely to be deteriorated, 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, a melt flow rate is measured based on JIS-K6922-2: 1997 appendix (190 degreeC, 21.18N load).
The density of the ethylene polymer 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, it is 0.870-0.898 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 film and a mark remains on the protected object. In addition, when the density exceeds 0.918 g / cm ³ , the adhesive strength becomes too weak and the effect as the adhesive layer cannot be obtained. In addition, a density is measured based on JIS-K6922-2: 1997 appendix (23 degreeC).

Further, the ratio (Mw / Mn) between the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the ethylene / α-olefin copolymer is not particularly limited, but is preferably 3.5 or less, more preferably. Is 1.5 to 3.0, particularly preferably 2.0 to 2.5. If it is the said range, there is no stickiness and it is preferable from a viewpoint of the contamination to a to-be-adhered body.
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.
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. Volume series, Sumitomo Chemical (
Examples include Sumikasen E, EP series, Excellen GMH, Excellen FX series, and the like.

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.
Moreover, the adhesive layer can use what mixed the said adhesive with the propylene-type resin used for this invention in consideration of the adhesiveness of a base material layer and an adhesive layer. When the above-mentioned pressure-sensitive adhesive is blended and used in the propylene-based resin used in the present invention, when the total amount 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 is 1 to 1%. 99% by weight, and the pressure-sensitive adhesive content is 99 to 1% by weight. Preferably, the content of the propylene-based resin is 5 to 75% by weight, and the content of the pressure-sensitive adhesive is 95 to 25% by weight. More preferably, the content of the propylene-based resin is 10 to 50% by weight, and the content of the pressure-sensitive adhesive is 50 to 90% by weight.

  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 0.5 to 80 μm, more preferably 1 to 60 μm, most preferably 2 to 2. 50 μm.

3. Peeling treatment layer In the surface protection film of the present invention, a peeling treatment layer is formed on the other surface of the pressure-sensitive adhesive layer formed on one of the base material layers made of the propylene-based resin, if necessary. The release treatment layer is not particularly limited as long as it is a known release layer. For example, a layer formed of a silicone-based or long-chain alkyl release treatment agent or a film surface is roughened to form unevenness and improve the release property. The layer formed from a silicone-based or long-chain alkyl-based release treatment agent is preferable from the viewpoint of transparency.

(1) Silicone-based or long-chain alkyl release agent A silicone-based release agent used for a layer formed of a silicone-based or long-chain alkyl-based release agent is a commonly used silicone mainly composed of dimethylpolysiloxane. System release treatment agents can also be used. It is also possible to use a silicone release treatment agent containing a three-dimensional organopolysiloxane. Specifically, a silicone-based mold release agent containing organopolysiloxane as a main component and blending cellulose derivatives such as methyl cellulose, ethyl cellulose and acetyl cellulose, alkyd resins, and 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. Cellulose derivatives and alkyd resins are preferably blended in an amount of 5 to 50% by weight in the silicone release 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-based release agent, it is preferable that the crosslinking agent is blended in an amount of 4 to 20% by weight, the catalyst is 5 to 10% by weight, and the resin as the third component is blended in an amount of 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 above-mentioned silicone release 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. -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. An exfoliating agent obtained from a reaction product obtained by reacting a long chain alkyl component of
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.

(2) Roughening of the film surface As a resin used to obtain a film having a layer having roughened film surfaces to form unevenness and improved peelability, the propylene / α-olefin block copolymer alone or the present invention is used. Propylene resin blended with propylene / α-olefin block copolymer, low density polyethylene alone, high density polyethylene alone, or low density polyethylene and high density polyethylene blended with propylene resin used in the present invention Or propylene / α-olefin block copolymer blended with low density polyethylene or high density polyethylene, or propylene resin used in the present invention with propylene / α-olefin block copolymer, low density polyethylene , High density polyethylene Those that have been blending two or more, or that such different thermoplastic resin compatibility propylene resin used in the present invention were blended and the like.
In order to roughen the film surface to form irregularities and improve the peelability, the irregularities on the film surface have a center plane average roughness (Ra) of 0.1 to 1.5 μm. 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.

  Here, since the value obtained by the measurement method of the center plane average roughness (Ra) differs depending on the measurement method and measurement conditions, in the present invention, the stylus type surface defined in JIS-B-0651 (1976). Measure with a roughness meter. The measurement conditions of the measuring instrument are: the radius of curvature of the stylus tip is 5 μm, the cutoff wavelength is 0.25 mm, the cutoff type is 2CR (phase compensation), the measurement speed is 0.3 mm / second, the measurement direction is the film MD direction, and the measurement The 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 the above resin composition, that is, the direction parallel to the longitudinal direction of the film.

Furthermore, it is also effective to combine a release treatment agent such as a silicone-based or long-chain alkyl release treatment agent with a technique of roughening the film surface to form unevenness and imparting releasability.
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 In the base material layer, the pressure-sensitive adhesive layer, and the release treatment agent layer used as necessary in the present invention, the film forming stability of the film and the secondary processing Various additives used as a known resin compounding agent within a range that does not impair the object of the present invention from the maintenance of quality as a film for handling and surface protection, for example, as described below, antioxidants, antiblocking An agent, a slip agent, a nucleating agent, a neutralizing agent, a light stabilizer, an antistatic agent, a tackifier, and the like may be blended and contained.

(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- Or the like can be mentioned Sufaito.

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.
And these antioxidants can be used 1 type or in combination of 2 or more types in the range which does not impair the effect of this objective.

  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 the antiblocking agent is 0.5 to 10 μm, preferably 1 to 7 μm, more preferably 1 to 5 μm, and most preferably 1 to 3 μm. If the average particle size is less than 0.5 μm, the slipperiness and opening property of the resulting film are inferior, which is not preferable. On the other hand, if it exceeds 10 μm, the transparency and scratching property are remarkably inferior. Also, the filter is clogged, the resin pressure rises and the sintered filter is damaged. 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, etc. 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 antiblocking agents can be used singly or in combination of two or more in a range that does not impair the effects of the present 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) Slip agent Examples of the slip agent include monoamides, substituted amides, bisamides, and the like, which can be used alone or in combination of two or more.
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 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 palmitic acid amide Etc.

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 bis behenic 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.
Examples of unsaturated fatty acid bisamides include ethylene bisoleic acid amide, hexamethylene bisoleic acid amide, N, N′-dioleyl adipic acid amide, N, N′-dioleyl sepacic acid amide and the like.
Examples of the aromatic bisamide include m-xylylene bis stearic acid amide and N, N′-distearylisophthalic acid amide.
In particular, among the above fatty acid amides, oleic acid amide, erucic acid amide, and behenic acid amide are preferably used.

  The compounding amount of the slip 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 0.4 parts 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). Benzyl compounds such as benzylidene) sorbitol, hydroxy-di (t-butylaluminum benzoate), 2,2-methylene-bis (4,6-di-t-butylphenyl) phosphoric acid and an aliphatic monocarbon having 8 to 20 carbon atoms Carboxylic acid lithium salt mixture (Asahi Denka Co., Ltd. make, brand name NA21) etc. are mentioned.
The blending amount of the nucleating agent is 0.0005 to 0.5 parts by weight, preferably 0.001 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. 0.1 parts by weight, more preferably 0.005 to 0.05 parts by weight. 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 etc. can be mentioned as nucleating agents 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 outside this range, the effect of improving transparency cannot be obtained. The polyethylene resin has a 190 ° C. melt flow rate (MFR) of 5 g / 10 min or more, preferably 7 to 500 g / 10 min, and more preferably 10 to 100 g / 10 min. When the MFR is less than 5 g / 10 min, the dispersion diameter of the high-density polyethylene resin is not sufficiently small, and the MFR itself becomes a foreign substance 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 that of the propylene-based resin used in 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 for 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, and Mizukarak (manufactured by Mizusawa Chemical Co., Ltd.).
The blending amount of the neutralizing agent is 0.01 to 1.0 part by weight, preferably 0.02 to 100 parts by weight of the propylene-based resin (A), the pressure-sensitive adhesive, and the release treatment agent used in the present invention. 0.5 parts by weight, more preferably 0.05 to 0.1 parts 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 As the antistatic agent, those conventionally used as an antistatic agent or an antistatic agent can be used without any particular limitation. For example, anionic surfactants and cationic surfactants can be used. , 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 polyethyleneimine and the like.

  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.

As the surfactant, nonionic surfactants and amphoteric surfactants are preferable. Among them, monoglycerides, diglycerides, boric acid esters, dialcohol alkylamines, dialcohol alkylamine esters, amides and other ester forms or nitrogen-containing forms Nonionic surfactants of the following: Betaine amphoteric surfactants are preferred.
In addition, as an antistatic agent, a commercial item can also be used, for example, electro stripper TS5 (trade name, glycerin monostearate manufactured by Kao Corporation), electro stripper TS6 (trade name, stearyl diethanolamine manufactured by Kao Corporation) ), Electro stripper EA (trade name, lauryl diethanolamine, manufactured by Kao Corporation), electro stripper EA-7 (trade name, polyoxyethylene lauryl amine capryl ester, manufactured by Kao Corporation), Denon 331P (Maruhishi Oil Chemical Co., Ltd.) ), Trademark, stearyl diethanolamine monostearate), Denon 310 (manufactured by Maruhishi Oil Chemical Co., Ltd., trademark, alkyldiethanolamine fatty acid monoester), Resist PE-139 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., trademark) Stearic acid mono & diglyceride boro Ester), Chemistat 4700 (Sanyo Chemical Industries Co., Ltd., trademark, alkyl dimethyl betaine), rheostat S (Lion Co., Ltd., trademark, alkyl diethanol amide) 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 content of the antistatic agent is within the above range, it is possible to prevent electrification and suppress deposits such as dust.

(8) Tackifiers Examples of tackifiers include, for example, aliphatic petroleum resins, alicyclic hydrogenated petroleum resins, aromatic petroleum resins, C5 petroleum resins, terpene resins, coumarone / indene resins, and phenols. Examples thereof include resins, rosin resins, tackifiers, and the like, and these can be used alone or in combination of two or more in a range that does not significantly impair the effects of the present invention.

The blending amount of the tackifying resin is not particularly limited as long as the effects of the present invention are not impaired, but 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. And 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. When the content of the tackifying resin is within the above range, the adhesive strength is improved.

(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.

5). Compounding and mixing of each component As a method of blending each of the above-mentioned additives, the additive is directly blended into each resin used in each layer of the base material layer, the pressure-sensitive adhesive layer, and the release treatment layer, and melt kneaded and used. It is also possible to add them during melt kneading. Furthermore, it can be directly blended after melt-kneading, or can be added as a masterbatch as long as the effects of the present invention are not significantly impaired. Moreover, you may mix | blend 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.

6). Method for Producing Surface Protection Film The surface protection film of the present invention can be produced by a known method for producing a laminated film.
The base material layer of the surface protective film used in the present invention is obtained by melt-kneading a propylene-based resin with an extruder, then feeding it to a die through a filter having a filtration diameter of 1 to 60 μm and extruding from the die. It is a thing.
Here, the thickness of the surface protective film is not particularly limited, but the thickness of the base material layer made of a propylene-based resin is usually 10 to 500 μm, preferably 20 to 200 μm, more preferably 30 to 100 μm, most preferably 40. ˜80 μm.
Examples of means for providing the pressure-sensitive adhesive layer on one side of the base material layer include known methods such as coating, curing, and lamination.

As a method of obtaining the pressure-sensitive adhesive layer by a solution coating method or the like, a pressure-sensitive adhesive layer dissolved in an organic solvent such as a toluene solution is applied to one side of the substrate layer with a roll coater or the like and then dried to form a pressure-sensitive adhesive layer. A method 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.
As a method of obtaining the pressure-sensitive adhesive layer by lamination, the pressure-sensitive adhesive is heated and melted by an extruder, and is co-extruded with a base material layer in a film form from a T-die, propylene kneaded with the pressure-sensitive adhesive by an extruder. After heat-melting the system resin and extruding it into a film form from the T die, the method of laminating on one side of the base material layer, the extruder is used to heat and melt the propylene resin kneaded with the adhesive, and from the T die Examples of the method include coextrusion with a base material layer in a film form. In those cases, it can be obtained by a production method in which a melted adhesive is supplied to a die through a filter having a filtration diameter of 1 to 60 μm and laminated as necessary.
In the present invention, adopting a method in which the pressure-sensitive adhesive layer is coextruded together with the base material layer is advantageous in that the pressure-sensitive adhesive remains on the adherend.

  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 the release treatment layer provided on the surface opposite to 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 a release treatment layer by coating with a solution coating method or the like, a release treatment agent dissolved in an organic solvent such as a toluene solution is applied to one side of a base material layer with a roll coater or the like, and then dried to release the release treatment agent. The method of hardening | curing and forming a peeling 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.

For method of applying the release treatment layer in a subsequent step, the coating amount of the releasing treatment agent is usually 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.}

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 that case, the adhesive which was fuse | melted as needed can be obtained with the manufacturing method which supplies to a die | dye through a filter with a filtration diameter of 1-60 micrometers, and laminates | stacks.
In the present invention, when the method of co-extruding the release treatment layer together with the base material layer from the T-die is advantageous in terms of contamination problems and economic points, it is suitable for the production of the release treatment layer. A method of co-extrusion and lamination using a T die is preferred.
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.

  By producing the surface protective film by such a method, one having a small fish eye can be continuously produced. As the extruder or die used in the present invention, an apparatus used in ordinary film forming can be used. Examples of the extruder include a single screw extruder and a twin screw extruder, and examples of the die include a T die and a circular die. Specifically, a film (unstretched film) can be produced by a known technique such as a casting method, a water-cooled inflation method, an air-cooled inflation method, or the like. In particular, from the viewpoint of productivity, the casting method is preferred, and as a casting method for producing an extrusion-molded body such as a film (unstretched film), a resin melt-kneaded by an extruder is extruded from a T die, It is cooled by being brought into contact with a roll through which a refrigerant such as water is passed, and thus a surface protecting film having generally good transparency and good thickness accuracy can be produced. Such a method is a preferable production method for the surface protective film.

  The temperature at which the propylene-based resin, the pressure-sensitive adhesive, and if necessary, the release treatment agent is melt-kneaded and the temperature at which the release treatment agent is extruded from the die is not particularly limited. In order to further suppress the molding process stability and the generation of fish eyes, the temperature is preferably 160 to 200 ° C. In the case of a T-die, the temperature is usually 180 to 260 ° C, and preferably 180 to 220 ° C in order to further suppress the molding process stability and the generation of fish eyes.

The filter used in the present invention is not particularly limited as long as it is a known filter, but a filter obtained by sintering a fibrous metal (generally made of stainless steel) into a mat shape is preferably used.
The filtration diameter of the filter used in the present invention is in the range of 1 to 60 μm, preferably 5 to 50 (μm), more preferably 10 to 40 (μm), and most preferably 10 to 20 (μm). The filtration diameter means a contaminant particle diameter with a collection efficiency of 95% that passes through the filter by the method of JIS-B8356. If the filtration diameter is too small, clogging occurs during film formation, and the load on the extruder tends to be excessive, and if the filtration diameter is too large, the filtration effect is insufficient and it tends to be difficult to suppress fish eyes.

The filter can be installed at any location between an extruder, which is a film processing apparatus, and a die. In general, a method of fitting into a part (breaker plate) to which a wire mesh is attached is simple, but it is preferable to install using a special casing (for example, a known candle filter, leaf disk filter (polymer filter)). Specific examples include a Dena filter manufactured by Nagase Sangyo Co., Ltd., and a pleated cylindrical film filter manufactured by Fuji Filter Industrial Co., Ltd.

The surface protective film of the present invention preferably has a fish eye of 10 / m ² or less, more preferably 5 / m ² or less, further preferably 3 / m ² or less, and 2 / m ² or less. Is particularly preferred.
When the fish eye exceeds 10 pieces / m ² on the surface protective film, the surface protective film is stuck on a polarizing plate or a retardation plate used as a liquid crystal display material and stacked and stored. There is a risk that the object to be protected will be dented.

  Since the surface protective film of the present invention has a base material layer obtained by passing a specific propylene-based resin through a filter having a filtration diameter of 1 to 60 μm, it can be produced without using a gear pump. Due to the extremely small number of fish eyes caused, it is extremely inconvenient as a polarizing plate or retardation plate used as a liquid crystal display material even with a small number of fish eyes. It is suitable for surface protection films that cause the object to be indented by fish eyes when stacked and stored on a plate, and is widely used for synthetic resin plates, decorative plates, metal plates, glass plates. It can also be used as a film for surface protection having excellent performance in building members such as.

  Examples of the present invention will be specifically described below, but the present invention is not limited to these examples. In addition, the measuring method of the characteristic value of the film shown in each Example and a comparative example, and the evaluation method are as follows.

1. Physical property measurement method, characteristic evaluation method (1) Resin pressure The resin pressure before filter filtration and the resin pressure after filter filtration were read from resin pressure gauges installed at the respective locations, and the differential pressure (ΔP) was determined. A smaller value of this differential pressure indicates a smaller extrusion load and is preferable.

(2) Fish Eye The number of fish eyes was counted from the area of 1 m ² of the obtained film. The obtained fish eye was measured with an optical microscope to have a major axis size of 100 μm or more (≧ 100 μm), smaller than 100 μm, 50 μm or more (<100 μm to ≧ 50 μm), smaller than 50 μm, 30 μm or more (<50 μm to ≧ 30 μm), smaller than 30 μm (< 30 μm) and divided the number (unit: pieces / m ² ). When the number of fish eyes is small, even if the surface protection film is attached to the object to be protected and stacked and stored, the object to be protected does not form a dent and is better as a film for surface protection.

2. Resin material (1) Base layer resin As propylene-based resin of the base layer, the propylene-based resin (PP-1 to 4) obtained in Production Examples 1 to 4 using a metallocene catalyst, and propylene / ethylene random copolymer by metallocene catalyst Combined (Wintech WFX4 (manufactured by Nippon Polypro), Wintech WFW4 (manufactured by Nippon Polypro), Wintech WFX6 (manufactured by Nippon Polypro), Wintech WSX02 (manufactured by Nippon Polypro)) , Propylene / ethylene / butene random copolymer (Novatech PP FX4G (manufactured by Nippon Polypro Co., Ltd.), Novatec PP FW4B (manufactured by Nippon Polypro))), propylene / ethylene random copolymer (manufactured by Nippon Polypro Co., Ltd.) Novatec PP FX3A (Nippon Polypro Co., Ltd.)), Ziegler catalyst 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. It carried out according to the method as described in the gazette.

(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 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. After further polymerization 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) 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) Adhesive layer resin As the adhesive layer resin, the ethylene / α-olefin random copolymer (PE-1) obtained in Production Example 5 using a metallocene catalyst, and as the rubber adhesive, natural rubber adhesive SMR (manufactured by Kasho Co., Ltd.), Kraton G1657 (styrene content: 13% by weight, manufactured by Kraton Polymer Japan Co., Ltd.), a hydrogenated styrene-butadiene-styrene block copolymer of a synthetic rubber adhesive, styrene- Dynalon 1321P (manufactured by JSR Corporation, styrene content: 10% by weight), which is a hydrogenated butadiene random copolymer, was used.

(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, ethylene / 1-hexene copolymer having a 1-hexene content of 18% by weight, an MFR of 2.4 g / 10 min, a density of 0.88 g / cm 3, and a molecular weight distribution (Mw / Mn) of 2.3 A coalescence (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).

(3) Release treatment layer As the release treatment layer, as a silicone release agent, X-62-2378 (manufactured by Shin-Etsu Chemical Co., Ltd.), as a three-dimensional organopolysiloxane, X-92-140 (manufactured by Shin-Etsu Chemical Co., Ltd.). ), As a long-chain alkyl-based release treatment agent, Pyroyl 101 (manufactured by Yushi Co., Ltd.) and a propylene / ethylene block copolymer (Novatech PP BC3HF (manufactured by Nippon Polypro Co., Ltd.)) using a Ziegler catalyst were used.

<Example 1>
Using a propylene-based resin WFX4 polymerized using a metallocene catalyst as a raw material, and using a T-die method film manufacturing apparatus equipped with an extruder with a diameter of 35 mmφ, a width 330 mmT die, an air knife and a cooling roll, between the extruder and the die Installed in Nagase Sangyo Co., Ltd. leaf disk filter (Denarabo 504 (diameter: 5 inches, number of filters: 5, filtration diameter: 10 μm)) before passing through the leaf disk filter (extruder and leaf disk filter And after passing through the leaf disk filter (between the leaf disk filter and the die), a resin pressure gauge was installed, and the indicated value of the resin pressure gauge was read. Under the conditions that the lip clearance of the T die is 0.8 mm, the setting temperature of the cylinder of the extruder, the setting temperature of the die, the setting temperature of the leaf disc filter is 220 ° C., the amount of extrusion is 10 kg / hour, and the cooling roll temperature is 35 ° C. Molded at a film forming speed of 10 m / min. A film with a film thickness of 40 μm was obtained. Fish eyes were evaluated from the obtained film. The results are shown in Table 2.
Next, the film formation was once stopped, the leaf disk filter was removed, and a film was obtained again under the same conditions. The fish eye of the obtained film was evaluated. The results are shown in Table 2.

<Example 2>
A film was formed and evaluated in the same manner as in Example 1 except that WFX4 in Example 1 was changed to WFW4. The results are shown in Table 2.

<Example 3>
A film was formed and evaluated in the same manner as in Example 1 except that WFX4 of Example 1 was changed to PP-1 pellets. The results are shown in Table 2.

<Example 4>
A film was formed and evaluated in the same manner as in Example 1 except that WFX4 in Example 1 was changed to WFX6. The results are shown in Table 2.

<Example 5>
A film was formed and evaluated in the same manner as in Example 1 except that WFX4 in Example 1 was changed to WSX02. The results are shown in Table 2.

<Example 6>
Except that the leaf disk filter of Example 1 was changed to a filtration diameter of 20 μm, the film was formed and evaluated by the same method as in Example 1. The results are shown in Table 2.

<Example 7>
A film was formed and evaluated in the same manner as in Example 1 except that the leaf disk filter of Example 1 was changed to a filtration diameter of 40 μm. The results are shown in Table 2.

<Comparative Example 1>
Except that WFX4 of Example 1 was changed to FX4G, a film was formed by the same method as in Example 1 and evaluated. The results are shown in Table 2.

<Comparative example 2>
Except that WFX4 of Example 1 was changed to FX3A, a film was formed by the same method as in Example 1 and evaluated. The results are shown in Table 2.

<Comparative Example 3>
Except that WFX4 of Example 1 was changed to FW4B, a film was formed and evaluated in the same manner as in Example 1. The results are shown in Table 2.

<Comparative example 4>
Evaluation was performed by forming a film of WFX4 of Example 1 in the same manner as in Example 1 except that FB3C was changed. The results are shown in Table 2.

<Comparative Example 5>
The WFX4 of Example 1 was formed and evaluated in the same manner as in Example 1 except that PP-2 was changed. The results are shown in Table 2.

<Comparative Example 6>
Evaluation was performed by forming a film of WFX4 of Example 1 by the same method as in Example 1 except that PP-3 was changed. The results are shown in Table 2.

<Comparative Example 7>
The WFX4 of Example 1 was formed and evaluated in the same manner as in Example 1 except that PP-4 was changed. The results are shown in Table 2.

<Comparative Example 8>
Except that the leaf disk filter of Example 1 was changed to a filtration diameter of 80 μm, the film was formed and evaluated by the same method as in Example 1. The results are shown in Table 2.

<Example 8>
To the base layer of the single-layer film obtained in Example 1, X-62-2378 (manufactured by Shin-Etsu Chemical Co., Ltd.) as an addition-type silicone release agent as a release treatment layer in a toluene solution (solid content 30%) A solution prepared by mixing a toluene / xylene solution (solid content 30%) of X-92-140 (manufactured by Shin-Etsu Chemical Co., Ltd.) as a three-dimensional organopolysiloxane so that the three-dimensional organopolysiloxane content is 30%. Was applied to one surface of the base material layer so as to be 0.38 g / m ² , followed by heat treatment at 120 ° C. for 1 minute to form a release treatment layer.
Furthermore, as rubber-based adhesive, natural rubber (trade name: SMR, manufactured by Kasho Co., Ltd.) 100% by weight, alicyclic petroleum resin (trade name: Alcon P100, manufactured by Arakawa Chemical Co., Ltd.) 50 parts by weight, terpene 10 parts by weight of a phenolic resin (trade name: PR-12603N, manufactured by Sumitomo Chemical Co., Ltd.) and 1 part by weight of an antioxidant (trade name: Irganox 1010 manufactured by Ciba Specialty Chemicals Co., Ltd.) were mixed in toluene and solidified. A rubber-based pressure-sensitive adhesive having a partial concentration of 20% was prepared, and this rubber-based pressure-sensitive adhesive was applied to the surface opposite to the surface of the release layer of the film having the release layer formed on the base layer with a reverse coater. Was dried at 100 ° C. for 2 minutes to prepare a surface protective film having a rubber-based pressure-sensitive adhesive layer having a thickness of 10 μm. Table 3 shows the evaluation results of the obtained surface protective film.

<Example 9>
As a base material layer, WFX4 of a propylene-based resin polymerized using a metallocene catalyst, PE-1 as an adhesive layer, and X-62-2378 as an addition type silicone-based release agent as a release treatment layer (Shin-Etsu Chemical Co., Ltd.) Toluene solution (manufactured by Shin-Etsu Chemical Co., Ltd.) as a three-dimensional organopolysiloxane with a toluene / xylene solution (solid content 30%) as a three-dimensional organopolysiloxane. A mixed solution was used so that the content was 30%.
Using an extruder with a substrate layer diameter of 35 mmφ, an adhesive layer with an aperture diameter of 20 mmφ, a two-layer T-die film production apparatus having an air knife and a cooling roll, Nagase Sangyo ( Co., Ltd. leaf disk filter (Denarabo 504 (diameter: 5 inches, number of filters: 5 sheets, filtration diameter: 10 μm)), T-die lip clearance of 0.8 mm, extruder cylinder set temperature, Die set temperature, leaf disk filter set temperature is 220 ° C., extrusion rate is 10 kg / hour, cooling roll temperature is 35 ° C., film forming condition is 10 m / min. A co-pressed two-layer film consisting of a two-layer T die film having a thickness of 10 μm was prepared.
The pressure-sensitive adhesive layer of the base material layer of the two-layer film thus obtained was added to a toluene solution (solid content 30%) of X-62-2378 (manufactured by Shin-Etsu Chemical Co., Ltd.) as an addition-type silicone release agent. A solution prepared by mixing a toluene / xylene solution (solid content 30%) of X-92-140 (manufactured by Shin-Etsu Chemical Co., Ltd.) as a three-dimensional organopolysiloxane so that the three-dimensional organopolysiloxane content is 30%. Was applied so as to be 0.38 g / m ² , followed by heat treatment at 120 ° C. for 1 minute to prepare a surface protective film on which a release treatment layer was formed. Table 3 shows the fish eye evaluation results of the obtained surface protective film.

<Example 10>
In Example 9, a film was formed and evaluated in the same manner as in Example 9 except that the leaf disk filter between the extruder and the die having a diameter of 35 mmφ of the base material layer was changed to a filtration diameter of 40 μm. The results are shown in Table 3.

<Example 11>
In Example 9, a film was formed and evaluated in the same manner as in Example 9 except that the leaf disk filter between the extruder and the die having a diameter of 20 mmφ of the adhesive layer was changed to a filtration diameter of 40 μm. The results are shown in Table 3.

<Example 12>
In Example 9, it evaluated by forming into a film by the same method as Example 9 except having changed the leaf disk filter between each extruder and die | dye of a base material layer and an adhesion layer into the filtration diameter of 40 micrometers. The results are shown in Table 3.

<Example 13>
In Example 9, except that PE-1 of the adhesive layer resin was changed to Clayton G1657, a film was formed and evaluated in the same manner as in Example 9. The results are shown in Table 3.

<Example 14>
In Example 9, it evaluated by forming into a film by the same method as Example 9 except having changed PE-1 of adhesion layer resin into Dynalon 1321P. The results are shown in Table 3.

<Example 15>
In Example 9, the adhesive layer resin PE-1 was formed into a film by the same method as in Example 9 except that the pellet mixture was changed to WFX4 (50 wt%) and Dynalon 1321P (50 wt%). It was. The results are shown in Table 3.

<Example 16>
WFX4 was used as the base material layer, Kraton G1657 was used as the pressure-sensitive adhesive layer, and BC3HF was used as the release treatment layer.
Using a three-layer T-die film manufacturing apparatus having an extruder with a substrate layer diameter of 35 mmφ, an adhesive layer with an aperture diameter of 20 mmφ, an exfoliation treatment layer with an aperture diameter of 20 mmφ, an air knife and a cooling roll, A leaf disk filter manufactured by Nagase Sangyo Co., Ltd. (Denarabo 504 (diameter: 5 inches, number of filters: 5 sheets, filtration diameter: 10 μm)) was installed between the extruder and the die, and the lip clearance of the T die was set at 0. 0. Film forming conditions of 8 mm, extruder cylinder set temperature, die set temperature, leaf disk filter set temperature 220 ° C., extrusion rate 10 kg / hour, cooling roll temperature 35 ° C., film take-up speed 10 m / min Thus, a co-pressed three-layer film made of a two-layer T-die film having a base material layer thickness of 30 μm and an adhesive layer thickness of 10 μm was produced. Table 3 shows the fish eye evaluation results of the obtained surface protective film.

<Reference Example 1>
In Example 9, a film was formed and evaluated in the same manner as in Example 9 except that an extruder having an adhesive layer with a diameter of 20 mmφ and a leaf disk filter between the dies were not used. The results are shown in Table 3.
<Comparative Example 9>
In Example 16, a film was formed and evaluated in the same manner as in Example 16 except that the leaf disk filter between the extruder and the die having a diameter of 35 mmφ of the base material layer was changed to a filtration diameter of 80 μm. The results are shown in Table 3.

  As is clear from the results in Tables 1, 2, and 3, in Examples 1 to 16 that satisfy the requirements of the present invention, the obtained film has extremely little fisheye caused by unmelted resin, whereas In Comparative Examples 1 to 9, which do not satisfy all or part of the requirements of the invention, it can be seen that there are many fish eyes and it is not suitable for a surface protective film.

  As described above, since the surface protective film of the present invention has extremely few fissure eyes caused by unmelted resin, it is particularly a surface protective film for polarizing plates and retardation plates used as liquid crystal display materials. In addition, it can be widely used as a surface protective film for building members such as synthetic resin plates, decorative plates, metal plates, and glass plates.

Claims (10)

On a base material layer made of a propylene-based resin (A) comprising a propylene homopolymer or a propylene / α-olefin random copolymer polymerized using a metallocene catalyst and having the following characteristics (A1) to (A4) A film for protecting a surface on which an adhesive layer is laminated,
The base material layer is formed by melting and kneading the propylene-based resin (A) with an extruder, then supplying the die through a filter having a filtration diameter of 1 to 60 μm, and extruding from the die. Surface 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) measured by a differential thermal scanning calorimeter (DSC) is 120 to 170 (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 the temperature rising elution fractionation (TREF) method is 10% by weight or less. The range (T ₁₀₀ -T) of the temperature (T ₁₀₀ ) when elution of the propylene resin (A) is 100% by weight from the temperature (T ₂₀ ) when 20% by weight is eluted by the temperature rising elution fractionation (TREF) method. _The film for surface protection according to claim 1, wherein ₂₀ ) has a characteristic of 30 ° C or lower.   The surface protection film according to claim 1 or 2, wherein the catalyst residue of the propylene-based resin (A) is 50 ppm or less.   The film for surface protection according to any one of claims 1 to 3, wherein a release treatment layer is laminated on the side opposite to the adhesive layer on the base material layer.   The pressure-sensitive adhesive layer is formed by melt-kneading a pressure-sensitive adhesive with an extruder, supplying the pressure-sensitive adhesive to a die through a filter having a filtration diameter of 1 to 60 μm, and extruding from the die. The film for surface protection of any one of these.   2. The release treatment layer is formed by melt-kneading a release treatment agent in an extruder, supplying the release treatment agent to a die through a filter having a filtration diameter of 1 to 60 μm, and extruding from the die. The film for surface protection of any one of -5. The film for surface protection according to claim 1, wherein the number of fish eyes is 10 / m ² or less.   It is used for the surface protection of a building member, The film for surface protection of any one of Claims 1-7 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 1-7 characterized by the above-mentioned. On a base material layer made of a propylene-based resin (A) comprising a propylene homopolymer or a propylene / α-olefin random copolymer polymerized using a metallocene catalyst and having the following characteristics (A1) to (A4) A method for producing a surface protective film in which an adhesive layer is laminated,
The base material layer is formed by melt-kneading the propylene-based resin (A) with an extruder, then supplying the die to a die through a filter having a filtration diameter of 1 to 60 µm, and extruding from the die. The manufacturing method of the film for surface protection of any one of 1-9.
(A1): Melt flow rate (MFR: 230 ° C., 21.18 N load) is 1 to 50 g / 10 minutes (A2): Melting peak temperature (Tmp) measured by a differential thermal scanning calorimeter (DSC) is 120 to 170 (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 the temperature rising elution fractionation (TREF) method is 10% by weight or less.