JP2010202697A - Polyolefin resin film and laminated item obtained using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyolefin resin film that has less fisheyes, is excellent in external appearances and exhibits excellent low-staining properties not to stain a mating member to be protected, and a laminated item using the same. <P>SOLUTION: The polyolefin resin film has a radical scavenger content of 0.1-3 ppm and at most 10 pieces/m<SP>2</SP>of fisheyes of 50 μm or larger. The laminated item is obtained using the same. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a polyolefin resin film and a laminate using the same.

  Polyolefin resins are used in a wide range of industrial fields because they are excellent in economic efficiency, mechanical strength, transparency, moldability, hygiene, etc. For example, they are processed into single-layer or multi-layer films, and optical protective films are used. First, it is widely used as a protective film for metal plates, resin plates, automobiles, electronic materials and the like.

  Demands for the quality of the protective film are becoming stricter year by year, and in particular, there is a demand for a reduction in fish eyes that impair the appearance, and a low contamination property that does not contaminate the counterpart material to be protected. Here, the fish eye is one of the drawbacks of a resin film that comes from the presence of foreign matter or gel in the film, and its peripheral part looks like a fish's eye when viewed with the naked eye, a polarizing plate, or a microscope.

  In the case of a polyolefin resin film, it is known that the gel which is one of the causes of fish eyes includes an unmelted gel and a crosslinked gel.

  The crosslinked gel is a gel in which a polyolefin resin is three-dimensionally crosslinked and is difficult to be melted by heating and dissolving in a solvent. On the other hand, an unmelted gel is a gel that can be melted or dissolved by heating, and when melt-kneaded by an extruder and extruded from a die or the like, the ratio of retaining the state as an unmelted gel is high. Incurs a decline.

  In particular, polyolefin resins obtained by high-pressure radical polymerization using a Bessel-type reactor or a tubular-type reactor, such as ethylene / vinyl acetate copolymer and low-density polyethylene, often have the above-mentioned unmelted gel and crosslinked gel. Are known. In the high-temperature reactor, hydrogen is radically extracted from the produced polymer and branches are formed. The reason for this is that this branched polymer is exposed to high temperature separators connected to the reactor and high temperature during the pelletization process, causing unmelted gel as aggregates or cross-linking reaction to form cross-linked gel. It is.

  Therefore, as a method for solving this problem, for example, when ethylene is polymerized under specific polymerization conditions in the presence of a radical polymerization initiator, it is proposed that a radical polymerization inhibitor coexists in the reaction system (for example, , See Patent Document 1).

  In addition, a method for removing the cross-linked gel and unmelted gel contained in the resin during molding has been proposed. For example, a gear pump for transporting a high-viscosity resin melt in an extruder, and a method of manufacturing a film by extruding a molten polyethylene resin have been proposed (see, for example, Patent Document 2). ).

  Furthermore, a film obtained by sandwiching a melted film-like polyolefin resin between a cast roll and an endless belt formed in an arc shape along the roll has been proposed (see, for example, Patent Document 3). ).

JP 2003-342307 A JP-A-8-103952 JP-A-8-25460

  However, although the method proposed in Patent Document 1 has a certain effect of reducing fish eye, its level is insufficient, and when it is used as a protective film formed on a polyethylene resin film to coexist with a radical polymerization inhibitor, There is a drawback of contaminating the partner.

  In addition, the methods described in Patent Documents 2 and 3 have not completely solved the problem that a crosslinked gel is generated because the polyolefin resin is exposed to a high temperature. In particular, since the method described in Patent Document 2 uses a sintered filter, it takes a long time to be exposed to a high temperature.

  On the other hand, a method of adding a radical scavenger to suppress the formation of cross-linked gel is conceivable, but a large amount of radical scavenger is necessary to suppress the formation of cross-linked gel of resin exposed to high temperature, and these are protected. When used as a film, it causes contamination.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a polyolefin resin film having a small number of fish eyes, an excellent appearance, and a low contamination property that does not contaminate a counterpart material to be protected, and a laminate thereof.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that a polyolefin resin film having a radical scavenger amount of 0.1 to 3 ppm and 50 μm or more of fish eyes of 10 pieces / m ² or less has a fish eye of It has been found that it has few appearances and is excellent in low contamination, and has completed the present invention. That is, the present invention is a polyolefin resin film having a radical scavenger amount of 0.1 to 3 ppm and a fish eye of 50 μm or more of 10 pieces / m ² or less, and a laminate using the polyolefin resin film.

  Hereinafter, the present invention will be described in detail.

In the polyolefin resin film of the present invention, the amount of radical scavenger is 0.1 to 3 ppm, and the number of fish eyes of 50 μm or more is 10 / m ² or less.

  The polyolefin resin film of the present invention is not particularly limited in length, width, and thickness, and is a planar molded product, including tapes and ribbons. The thickness of the polyolefin resin film of the present invention is preferably 1 to 200 μm, more preferably 5 to 150 μm, and particularly preferably 10 to 100 μm, from the viewpoint of easy handling of the film.

  There is no restriction | limiting in particular as polyolefin resin in the polyolefin resin film of this invention, For example, polyethylene, an ethylene-type copolymer, a polypropylene, a polypropylene-type copolymer, Furthermore, the chlorinated material of these polyolefin resin etc. can be mentioned. More specifically, examples of the polyethylene include high density polyethylene, medium density polyethylene, low density polyethylene, linear low density polyethylene, and ultra low density polyethylene. Examples of the ethylene copolymer include an ethylene-α-olefin copolymer, an ethylene-vinyl ester copolymer, an ethylene-acrylic acid copolymer, an ethylene-methacrylic acid copolymer, and an ethylene-acrylic acid ester copolymer. And ethylene-methacrylic acid ester copolymer. Specifically, ethylene-1-butene copolymer, ethylene-1-hexene copolymer, ethylene-1-octene copolymer, ethylene-4 -Methylpentene-1 resin, ethylene-vinyl acetate copolymer, saponified ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol resin, ethylene-propylene copolymer, ethylene-ethyl acrylate copolymer, ethylene- Examples thereof include an ethyl methacrylate copolymer. Examples of the polypropylene-based copolymer include a polypropylene block copolymer and a polypropylene random copolymer. These polyolefin resins can be used alone or in combination.

  Among them, since the polyolefin resin film obtained is flexible, the polyolefin resin in the polyolefin resin film is at least one selected from the group consisting of polyethylene, ethylene-vinyl acetate copolymer, and saponified ethylene-vinyl acetate copolymer. Preferably, it is a kind of polyolefin resin.

When the polyolefin resin film is a polyethylene film, the density of the polyolefin resin film is preferably 931 to 936 kg / m ³ from the viewpoint that the obtained film is flexible and easy to handle. When the polyolefin resin film is an ethylene-vinyl acetate copolymer film, the density of the polyolefin resin film is preferably 923 to 970 kg / m ³ because the resulting film is flexible and easy to handle. When the polyolefin resin film is a saponified film of ethylene-vinyl acetate copolymer, the density of the polyolefin resin film is preferably 923 to 1200 kg / m ³ from the viewpoint that the obtained film is flexible and easy to handle.

  There is no particular limitation on the polymerization method for synthesizing these polyolefin resins, and generally known methods can be used, for example, high pressure radical polymerization method, medium-low pressure polymerization method, solution polymerization method, slurry polymerization method, etc. Can be mentioned.

  Moreover, there is no restriction | limiting in particular in the catalyst used for superposition | polymerization, For example, a peroxide type catalyst, a Ziegler-Natta catalyst, a metallocene catalyst etc. are mentioned.

The molecular weight of the polyolefin resin in the polyolefin resin film of the present invention is not limited as long as the polyolefin resin dissolves in the solvent, but the film strength is maintained and the fluidity of the polymer solution is maintained to obtain a thin film. The weight average molecular weight ( _Mw ) in terms of linear polyethylene is preferably 10,000 to 1,000,000, more preferably 20,000 to 700,000, and particularly preferably 25,000 to 300,000.

  The radical scavenger contained in the polyolefin resin film of the present invention is not limited at all. For example, phenol radical scavenger, phosphorus radical scavenger, sulfur radical scavenger, amine radical scavenger, lactone radical Examples include scavengers and vitamin E radical scavengers.

  Examples of the phenol radical scavenger include 2,6-di-t-butyl-4-methylphenol, 2,6-di-t-butyl-4-ethylphenol, and 3,5-di-t-butyl. -4-hydroxytoluene, 2,2'-methylenebis (4-methyl-6-tert-butylphenol), 2,2'-methylenebis (4-ethyl-6-tert-butylphenol), 4,4'-butylidenebis (3 -Methyl-6-t-butylphenol), 4,4'-thiobis (3-methyl-6-t-butylphenol), 2,5-di-t-butylhydroquinone, 2,5-di-t-amylhydroquinone, Pentaerythritol tetrakis (3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate), octadecyl-3- (3,5-di-tert-butyl-4) Hydroxyphenyl) propionate, tetrakis [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane, 1,3,5-trimethyl-2,4,6-tris ( 3,5-di-tert-butyl-4-hydroxybenzyl) benzene, calcium (3,5-di-tert-butyl-4-hydroxy-benzyl-monoethyl-phosphate), triethylene glycol-bis [3- ( 3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], pentaerythritol tetrakis [3- (3,5-di-tert-butylanilino) -1,3,5-triazine], 3,9-bis [1,1-dimethyl-2- {β- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy} ethyl] 2 , 4,8,10-tetraoxaspiro [5,5] undecane, bis [3,3-bis (4′-hydroxy-3′-t-butylphenyl) butyric acid] glycol ester, triphenol, 2,2 ′ -Ethylidenebis (4,6-di-t-butylphenol), N, N'-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl] hydrazine, 2,2'-oxamide bis [Ethyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 1,1,3-tris (3 ′, 5′-di-t-butyl-4′-hydroxybenzyl) -S-triazine-2,4,6 (1H, 3H, 5H) -trione, 1,3,5-tris (4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate, 3, 5-di a mixture of t-butyl-4-hydroxyhydrocinnamic acid triester and 1,3,5-tris (2-hydroxyethyl) -S-triazine-2,4,6 (1H, 3H, 5H), N, N Hexamethylene bis (3,5-di-tert-butyl-4-hydroxy-hydrocinnamide), 3,9-bis [2- {3- (3-tert-butyl-4-hydroxy-5-methylphenyl) ) Propionyloxy} -1,1-dimethylethyl] -2,4,8,10-tetraoxaspiro [5.5] undecane.

  Examples of the phosphorus radical scavenger include tris (mixed, mono and dinonylphenyl) phosphite, tris (2,3-di-t-butylphenyl) phosphite, 4,4′-butylidene-bis ( 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-tert-butyl-6-methylphenyl) ethyl phosphite, tris (2,4-di-tert-butylphenyl) phosphite, bis (2,4-di-tert-butylphenyl) pentaerythritol Diphosphite, tetrakis (2,4-di-t-butylphenyl) -4,4'-biphenylene phosphite, bis (2,6-di-t-butyl) 4-methylphenyl) pentaerystol diphosphite, tetrakis (2,4-di-t-butylphenyl) 4,4'-biphenylene diphosphite, triphenyl phosphite, diphenyldecyl phosphite, tridecyl phosphite Phyto, trioctyl phosphite, tridodecyl phosphite, trioctadecyl phosphite, trinonyl phenyl phosphite, tridodecyl trithiophosphite and the like can be mentioned.

  Examples of the sulfur radical scavenger include dilauryl 3,3′-thiodipropionate, dimyristyl 3,3′-thiodipropionate, dioctadecyl 3,3′-thiodipropionate, lauryl stearyl 3,3. '-Thiodipropionic acid ester, pentaerythrityl tetrakis (3-laurylthiopropionate), dioctadecyl sulfide, 2-mercaptobenzimidazole, zinc salt of 2-mercaptobenzimidazole, nickel diethyldithiocarbamate, nickel dibutyldithiocarbamate 1,3-bis (dimethylaminopropyl) -2-thiourea, tributylthiourea and the like.

  Examples of the amine radical scavenger include 2,2,4-trimethyl-1,2-dihydroquinoline polymer, 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline, diphenylamine and acetone. Reaction product of phenyl-1-naphthylamine, alkylated diphenylamine, octylated diphenylamine, 4,4′-bis (α, α-dimethylbenzyl) diphenylamine, p- (p-toluenesulfonylamido) diphenylamine, N, N′- Di-2-naphthyl-p-phenylenediamine, N, N′-diphenyl-p-phenylenediamine, N-phenyl-N′-isopropyl-p-phenylenediamine, N-phenyl-N ′-(1,3-dimethyl) Butyl) -p-phenylenediamine, N-phenyl-N ′-(3-methacryloylio And xyl-2-hydroxypropyl) -p-phenylenediamine.

  Examples of the lactone radical scavenger include a reaction product of 3-hydroxy-5,7-di-t-butylfuran-2-one and O-xylene.

  Examples of the vitamin E-based radical scavenger include 3,4-dihydro-2,5,7,8-tetramethyl-2- (4,8,12-trimethyltridecyl) -2H-benzopyran-6-ol. Etc.

  These radical scavengers can be used in combination of two or more in order to exhibit a greater effect.

  Among these radical scavengers, 2,6-di-t-butyl-4-methylphenol and 2,6-di-t-butyl-4-ethylphenol have a great effect of suppressing the formation of crosslinked gel. Is preferred.

  The amount of the radical scavenger in the polyolefin resin film of the present invention is 0.1 to 3 ppm, more preferably 0.1 to 2 ppm, and particularly preferably 0.1 to 1 ppm. When the amount of the radical scavenger exceeds 3 ppm, the counterpart material may be contaminated when the polyolefin resin film is used as a protective film, and when it is less than 0.1 ppm, the polyolefin resin film may be colored.

Further, the number of fish eyes of 50 μm or more in the polyolefin resin film of the present invention is 10 / m ² or less, more preferably 5 / m ² or less of fish eyes of 50 μm or more, and particularly preferably 3 / m 2. ² or less. When the number of fish eyes of 50 μm or more exceeds 10 / m ² , for example, it cannot be used as a protective film that requires high quality.

  The fish eye here is defined as a region showing an optically non-uniform state in the polyolefin resin film.

  The polyolefin resin film of the present invention may contain various additives as long as the effects of the present invention are not impaired. Examples of additives include dyes, organic pigments, inorganic pigments, inorganic reinforcing agents, plasticizers, acrylic processing aids and other processing aids, ultraviolet absorbers, light stabilizers, foaming agents, lubricants, waxes, crystal nucleating agents. , Plasticizer, mold release agent, hydrolysis inhibitor, antiblocking agent, antistatic agent, antifogging agent, antifungal agent, rust inhibitor, ion trap agent, flame retardant, flame retardant auxiliary, inorganic filler, organic A filler etc. can be mentioned.

  Examples of the method of obtaining the polyolefin resin film of the present invention include a method of forming a film after heating and melting the polyolefin resin, and a method of forming a film after dissolving the polyolefin resin in a solvent.

  Examples of the method for forming a film after heating and melting the polyolefin resin include an inflation method (air cooling method, water cooling method), a T-die method, a calendar method, and the like.

  At that time, the radical scavenger can be added, for example, by mixing it with the polyolefin resin pellets as it is, or by mixing the radical scavenger with the polyolefin resin pellets and a master batch previously kneaded into the polyolefin resin.

  The amount of radical scavenger added is preferably 0.1 to 3 ppm, more preferably 0.1 to 2 ppm, and particularly preferably 0.1 to 1 ppm. When the amount of the radical scavenger exceeds 3 ppm, the counterpart material may be contaminated when the polyolefin resin film is used as a protective film, and when it is less than 0.1 ppm, the polyolefin resin film may be colored.

  Examples of the method for forming a film after dissolving the polyolefin resin in the solvent include, for example, a step of preparing the polyolefin solution by dissolving the polyolefin resin in the solvent, and then continuously casting the polyolefin solution on the substrate. And a solution casting method comprising a step of evaporating the solvent by heating.

  At that time, for example, the radical scavenger is mixed with the polyolefin resin pellets in the solution as it is, or added by mixing the radical scavenger in the solution with the master batch and the polyolefin resin pellets previously kneaded into the polyolefin resin. can do.

  The amount of radical scavenger added is preferably 0.1 to 3 ppm, more preferably 0.1 to 2 ppm, and particularly preferably 0.1 to 1 ppm. When the amount of the radical scavenger exceeds 3 ppm, the counterpart material may be contaminated when the polyolefin resin film is used as a protective film, and when it is less than 0.1 ppm, the polyolefin resin film may be colored.

  Among them, the polyolefin resin film obtained has a small fish eye, a step of preparing a polyolefin solution by dissolving the polyolefin resin in a solvent, and then continuously casting the polyolefin solution on the substrate, followed by heating to the solvent A solution casting method comprising a step of evaporating water is preferred.

  Each step of the solution casting method, which is a preferred production method, will be described below.

1) Step of preparing polyolefin solution The solvent used in the step of preparing polyolefin solution is not particularly limited as long as it is a solvent that dissolves polyolefin resin. For example, halogen solvent, boiling point is 70 to 140 ° C., solubility index is Examples thereof include at least one non-halogen solvent selected from an aliphatic hydrocarbon compound, an aromatic hydrocarbon compound, an ether compound, and an acetal compound that are 13 to 20 MPa ^1/2 . These solvents can be used in combination of two or more, and the ratio is not particularly limited.

  Examples of the halogen-based solvent include 1,1-dichloroethane, 1,2-dichloroethane, methylene chloride, chloroform, 1,1,1-trichloroethane, 1,1,2-trichloroethane, carbon tetrachloride, trichloroethylene, and perchloroethylene. Chlorinated solvents such as ethane, brominated solvents such as ethane bromide, fluorinated solvents such as monofluorobenzene, 1,4-difluorobenzene, perfluoroheptane, perfluorooctane, dichloropentafluoropropane, bromochloromethane, 1, Examples include a solvent containing bromine and fluorine such as 2-dibromo-1,1-difluoroethane.

Examples of the aliphatic hydrocarbon compound, aromatic hydrocarbon compound, ether compound and acetal compound having a boiling point of 70 to 140 ° C. and a solubility index of 13 to 20 MPa ^1/2 include n-heptane, 2- Methylhexane, 3-methylhexane, 2,3-dimethylpentane, 2,4-dimethylpentane, n-octane, 2,2,3-trimethylpentane, isooctane, 2,2,5-trimethylhexane, 1-heptene, 1-octene, methylcyclopentane, cyclohexane, methylcyclohexane, ethylcyclohexane, cyclohexene and other aliphatic hydrocarbon compounds, benzene, toluene, m-xylene, p-xylene, ethylbenzene and other aromatic hydrocarbon compounds, cyclopentylmethyl Ether, ethylamino ether, dioxa And ether compounds such as dipropyl ether and acetal compounds such as diethyl acetal.

  Among these solvents, a solvent capable of dissolving the polyolefin resin at, for example, 80 to 120 ° C. is preferable from the viewpoint of solubility of the polyolefin resin, and a solvent having a low boiling point is preferable from the viewpoint of evaporation of the solvent. From these viewpoints, 1,1,2-trichloroethane, n-heptane, methylcyclohexane, toluene and cyclopentylmethyl ether are preferable, and 1,1,2-trichloroethane and methylcyclohexane are more preferable.

  The melting temperature of the polyolefin resin is appropriately determined depending on the solvent and polyolefin to be used. If the polyolefin resin does not dissolve below the boiling point of the solvent used, it can be dissolved at a temperature above the boiling point of the solvent using a pressure vessel if necessary, but the boiling point at normal pressure of the solvent used. It is preferable from the economical aspect to dissolve in the following. For example, the melting temperature is preferably 60 to 200 ° C, and more preferably 70 to 150 ° C.

  The dissolution time depends on the shape of the polyolefin resin used and the dissolution temperature, and is preferably 20 minutes to 8 hours, for example, and more preferably 30 minutes to 2 hours. Moreover, it is necessary to completely dissolve the polyolefin resin, and it is preferable to dissolve the polyolefin resin until a certain solution viscosity is reached.

  Moreover, there is no restriction | limiting in particular in the apparatus to melt | dissolve, For example, a vessel, a tube, a horizontal reactor, an extruder etc. can be used. The dissolution is preferably carried out with stirring.

  The polyolefin solution obtained by dissolving the polyolefin resin in a solvent is preferably filtered to remove foreign substances, and the filtration is preferably performed in a state where the polyolefin resin is dissolved. There is no restriction | limiting in particular in the filtration method, A well-known method can be used, For example, natural filtration, centrifugal filtration, pressure filtration, reduced pressure filtration, decantation etc. are mentioned. Examples of the filter medium include metal mesh, laminated wire mesh sintered body, metal nonwoven fabric sintered body, resin woven fabric, resin nonwoven fabric, resin membrane, filter fabric, paper, and the like. These filter media can be used singly or in combination, and filtration can be performed in multiple stages in order to increase filtration accuracy. The opening of the filter medium is preferably 100 μm or less, more preferably 50 μm or less, and particularly preferably 30 μm or less.

  There is no restriction | limiting in particular in the temperature at the time of filtering a polyolefin solution, For example, it can carry out in the state etc. in which the polyolefin resin melt | dissolved below the boiling point of the solvent to be used.

  There is no restriction | limiting in particular in the density | concentration of polyolefin solution, It can set suitably with the selected solvent, 0.1 to 50 weight% is preferable, 1 to 30 weight% is further more preferable, and 5 to 25 weight% is especially. preferable.

2) Step of evaporating solvent As a method of evaporating the solvent, for example, a method in which a polyolefin solution is continuously cast on a substrate to form a thin film and then heated is exemplified.

  As the base material, various resin films represented by polyester films such as polyethylene terephthalate (PET) and polyethylene naphthalate, and various resins whose surfaces are subjected to surface treatment by hard coating such as silicon treatment and acrylic resin. Examples thereof include various resin films obtained by subjecting these resin films to metal vapor deposition. Furthermore, examples include metal foils such as aluminum, copper, and stainless steel, various films such as metal films and metal sheets, polymer coatings on these metal materials as necessary, and inorganic coatings. it can. Further, it can be cast on a heated rotating metal drum as necessary, and can be cast on an endless polymer belt or metal belt.

  Examples of the method for casting the polyolefin solution on the substrate include a gravure coater, a comma coater, a die coater, and a double Mayer bar coater, which are known methods. When heating is required to dissolve the polyolefin resin and the boiling point of the solvent is low, a die coater is used to suppress the increase in viscosity of the polyolefin solution due to rapid volatilization of the solvent during the casting process. Is preferred. The thickness of the polyolefin solution on the substrate immediately after being formed by casting is preferably 3 to 500 μm, and the casting speed is 0.5 to 50 m independent of the thickness of the polyolefin resin layer immediately after being formed on the substrate. / Min is preferred.

  Drying of the polyolefin solution layer formed on the substrate can be carried out in one step to multiple steps, and the temperature range is preferably 50 to 200 ° C. When drying in multiple steps, the temperature is 50 to 100 ° C. It is preferable to take a method such as primary drying and secondary drying in the range of 100 to 200 ° C. Moreover, it is also possible to perform drying in 3 steps or more as required. This drying can be carried out efficiently industrially using a drying furnace adjacent to the die coater. The polyolefin resin layer is peeled off from the substrate after sufficient drying and wound up, or peeled off from the substrate in the course of drying, and only the polyolefin resin layer is dried and wound into a film, and the polyolefin resin A film can be obtained.

The laminate of the present invention is a laminate using a polyolefin resin film in which the amount of radical scavenger is 0.1 to 3 ppm and the number of fish eyes of 50 μm or more is 10 / m ² or less.

  Examples of the layer laminated with the polyolefin resin film of the present invention include, for example, a thermoplastic resin film such as the polyolefin resin film of the present invention, PET film, cloth, nonwoven fabric, synthetic fiber, synthetic leather, leather, metal, rubber, and thermoplastic elastomer. , One or more layers selected from the group consisting of thermoplastic resins, thermosetting resins, paper, wood, glass, stones, ceramics, and porcelain may be used, and these may be laminated in one layer or two or more layers. A laminate with a thermoplastic resin film is preferred because a laminate with a wide range of use can be obtained.

  In order to produce the laminate of the present invention, for example, molding methods such as multilayer casting, multilayer extrusion molding, multilayer injection molding, multilayer laminate molding, multilayer dry laminate molding, multilayer inflation molding, multilayer blow molding and the like can be mentioned. . Moreover, the method of pasting together with an adhesive agent, an adhesive, hot melt, etc., or heat-sealing with a high frequency welder etc. is mentioned.

  INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a polyolefin resin film that has a very wide range of applications in industry, has a small fish eye and is excellent in appearance, and is excellent in low contamination, and a laminate using the polyolefin resin film. The polyolefin resin film of the present invention is useful, for example, as a protective film that requires high quality.

  The present invention will be described in more detail with reference to the following examples. However, these are examples for helping understanding of the present invention, and the present invention is not limited to these examples.

<Polyolefin resin>
As the polyolefin resin used in the examples, a resin to which no additive was added was used.

(1) Polyethylene 1) Low density polyethylene LDPE; Petrocene (registered trademark) 220K (MFR = 1.1 g / 10 min, density = 931 kg / m ³ ), manufactured by Tosoh Corporation 2) Linear low density polyethylene L-LDPE- 1; Nipolon-L (registered trademark) M70K (ethylene-butene copolymer, MFR = 20 g / 10 minutes, density = 936 kg / m ³ ), Tosoh Corporation L-LDPE-2; Nipolon-Z (registered trademark) YB10T (ethylene-hexene copolymer, MFR = 1.0 g / 10 min, density = 920 kg / m ³ ), manufactured by Tosoh Corporation 3) high-density polyethylene HDPE; Nipolon Hard (registered trademark) 8022 (MFR = 0.35 g / 10 min, density = 958kg ^{/ m} 3), Tosoh Corporation (2) an ethylene - vinyl acetate copolymer EVA; ur Helical (R) 546k (vinyl acetate content 10wt%, MFR = 6g / 10 min, density = 929kg ^{/ m} 3), Tosoh Corporation (3) Ethylene - vinyl acetate copolymer saponified EVAOH; Melthene H ( (Registered trademark) H-6051K (MFR = 5.5 g / 10 min, density = 970 kg / m ³ ), manufactured by Tosoh Corporation <Radical scavenger>
BHT (2,6-di-t-butyl-4-methylphenol); Sumilyzer (registered trademark) BHT, manufactured by Sumitomo Chemical Co., Ltd. AO-60 (pentaerythritol tetrakis (3- (3,5-di-t- Butyl-4-hydroxyphenyl) propionate)); ADK STAB (registered trademark) AO-60, manufactured by Asahi Denka Kogyo Co., Ltd. <Substrate>
PET film; Melinex (registered trademark) type S (thickness: 100 μm), manufactured by Teijin DuPont Films Co., Ltd. <Casting>
The coating was performed using a coating machine provided with a die having a width of 300 mm that can be heated. The polymer solution dissolved in the autoclave was transferred to a 5 L scale pressurizable tank equipped with a heating jacket and a nitrogen introduction valve manufactured by Unicontrols. The polymer solution in the tank was transferred to the die by pressurizing the tank. The tank and the die were connected to the extraction valve at the bottom of the tank with a Teflon (registered trademark) tube in which a hose heater manufactured by Mysec Co., Ltd. was applied, and kept at a constant temperature.

  The temperature of the die is controlled using a mold temperature controller TSW-75S manufactured by Nippon Mold Industry Co., Ltd., and the temperature of the hose heater and the heating tank is adjusted using HST-120CT manufactured by Mysec Co., Ltd. .

<Fisheye measurement>
A fluorescent lamp was irradiated from under the obtained film, and the number and size of fish eyes in the film were measured visually or using a magnifying glass, and the number was calculated as the number per 1 m ² .

<Measurement of amount of radical scavenger>
The obtained film was put into a mixed solvent of chloroform / methanol = 8/2 (volume ratio), the solvent was removed from the extract extracted at 90 ° C. for 2 hours, and methanol was added to make a constant volume. The amount of the radical scavenger of this solution was quantified using a gas chromatograph mass spectrometer (Turbomas-Gold, manufactured by PerkinElmer).

<Measurement of contamination>
The obtained polyolefin resin film was bonded to a polycarbonate plate to prepare a laminate, and then left for 24 hours in a gear oven set at 60 ° C. and then taken out. The polyolefin resin film was peeled off from the polycarbonate plate and visually checked for contamination on the surface. It was evaluated with. The evaluation results were ◎ when no contamination was observed, ◯ when almost no contamination was observed, and × when contamination was observed.

<Measurement of density>
The density of the polyolefin resin film was measured by a density-squeeze tube method in accordance with JIS K7112 (1999).

Example 1
2.5 kg of LDPE pellets, 0.005 g (2 ppm) of BHT, and 15.4 kg of methylcyclohexane were charged into a 30 L autoclave and stirred at 110 ° C. for 2 hours under heating to dissolve LDPE to obtain a polyolefin solution. While filtering this solution through a 500 mesh metal net, 3 L of the solution was transferred to a 5 L tank heated to 105 ° C. The tank is pressurized with nitrogen and fed to a 300 mm wide coating die heated to 105 ° C. through a Teflon (registered trademark) tube with a heating jacket kept at 105 ° C., and the polyolefin solution is the base material from the die. It was cast on a PET film and dried at 150 ° C. The speed of the PET film was set at 2 m / min. The LDPE film was peeled off from the laminate of the obtained PET film and LDPE film to obtain a polyolefin resin film. The thickness of the obtained polyolefin resin film, the amount of radical scavenger, contamination, fish eye, and density were measured. The results are shown in Table 1.

得られたポリオレフィン樹脂フィルムの５０μｍ以上のフィッシュアイは０．７個／ｍ^２で、汚染性も無く、優れた品質のフィルムであった。

The resulting polyolefin resin film had a fish eye of 50 μm or more, 0.7 pieces / m ² , no contamination, and an excellent quality film.

Examples 2-6
Examples except that the polyolefin resin, radical scavenger, solvent, charge amount, dissolution temperature, and dissolution time shown in Table 1 were used, and the temperature of the coating die, Teflon (registered trademark) tube, and tank was lowered by 5 ° C. from the dissolution temperature. 1 was used to obtain a polyolefin resin film. The obtained polyolefin resin film was evaluated in the same manner as in Example 1. The results are also shown in Table 1.

The obtained polyolefin resin film had a fish eye of 50 μm or more of 0.9 to 1.5 pieces / m ² , no contamination, and was an excellent quality film.

Comparative Example 1
LDPE pellets 2.5 kg, BHT 0.075 g (30 ppm) and 1,1,2-trichloroethane 20 L (28.8 kg) were charged into a 30 L autoclave and stirred at 110 ° C. for 2 hours under heating to dissolve LDPE. A polyolefin solution was obtained. While filtering this solution through a 500 mesh metal net, 3 L of the solution was transferred to a 5 L tank heated to 105 ° C. The tank is pressurized with nitrogen and fed to a 300 mm wide coating die heated to 105 ° C. through a Teflon (registered trademark) tube with a heating jacket kept at 105 ° C., and the polyolefin solution is the base material from the die. It was cast on a PET film and dried at 150 ° C. The speed of the PET film was set at 2 m / min. The polyolefin resin film was obtained by peeling from the PET film. The obtained polyolefin resin film was evaluated in the same manner as in Example 1. As a result, the thickness was 20 μm, the radical scavenger 20 ppm, the contamination property x, 50 μm or more fish eyes 1.5 / m ² , and the density 931 kg / m ³ . .

  The obtained polyolefin resin film was a film having poor contamination.

Comparative Example 2
A polyolefin resin film was obtained in the same manner as in Example 1 except that 0.005 g of BHT was not used. The obtained polyolefin resin film was slightly colored yellow.

Comparative Example 3
After dry blending 5 kg of LDPE pellets and 0.45 g (90 ppm) of BHT, a film was produced by the T-die method, which is a method of forming a film after heating and melting the polyolefin resin. The apparatus used was a lab plast mill manufactured by Toyo Seiki Seisakusho Co., Ltd. connected to a φ20 mm single-screw extruder and a 250 mm wide T-die. The temperature of the extruder and the T die was 180 ° C., and the screw rotation speed was 50 rpm. When the obtained polyolefin resin film was evaluated in the same manner as in Example 1, the thickness was 19 μm, the radical scavenger was 50 ppm, the fouling property was x, 20 fish eyes of 50 μm or more / m ² , and the density was 931 kg / m ³ .

  The obtained polyolefin resin film was a film with many fish eyes and poor contamination.

Comparative Example 4
After dry blending 5 kg of L-LDPE-2 pellets and 0.25 g (50 ppm) of BHT, a polyolefin resin film was prepared in the same manner as in Comparative Example 3 and evaluated in the same manner as in Example 1. The thickness was 20 μm and the radical scavenger. It was 30 ppm, contamination ×, 15 fish eyes of 50 μm or more / m ² , and a density of 920 kg / m ³ .

  The obtained polyolefin resin film was inferior in soiling properties, had a small amount of radical scavengers, and was exposed to high temperatures, so that it was a film with many fish eyes.

Comparative Example 5
After dry blending 5 kg of HDPE pellets and 0.25 g (50 ppm) of BHT, a polyolefin resin film was produced in the same manner as in Comparative Example 2 except that the temperature of the extruder and T die was 200 ° C. As a result, the thickness was 20 μm, the radical scavenger 20 ppm, the contamination ×, the fish eyes of 50 μm or more 35 / m ² , and the density 958 kg / m ³ .

  The obtained polyolefin resin film was inferior in soiling properties, had a small amount of radical scavengers, and was exposed to high temperatures, so that it was a film with many fish eyes.

Comparative Example 6
After dry blending 5 kg of EVA pellets and 0.25 g (50 ppm) of BHT, a polyolefin resin film was prepared in the same manner as in Comparative Example 2 except that the temperature of the extruder and T die was 180 ° C. As a result, the thickness was 20 μm, the radical scavenger was 20 ppm, the contamination property was x, 25 fish eyes of 50 μm or more / m ² , and the density was 929 kg / m ³ .

  The obtained polyolefin resin film was inferior in soiling properties, had a small amount of radical scavengers, and was exposed to high temperatures, so that it was a film with many fish eyes.

Comparative Example 7
After dry blending 5 kg of EVAOH pellets and 0.25 g (50 ppm) of BHT, a polyolefin resin film was prepared in the same manner as in Comparative Example 2 except that the temperature of the extruder and T die was 180 ° C. As a result, the thickness was 20 μm, the radical scavenger was 25 ppm, the contamination ×, the fish eyes of 50 μm or more were 30 / m ² , and the density was 970 kg / m ³ .

  The obtained polyolefin resin film was inferior in soiling properties, had a small amount of radical scavengers, and was exposed to high temperatures, so that it was a film with many fish eyes.

Example 7
The LDPE film obtained in Example 1 and the EVA film obtained in Example 5 were bonded together to obtain a laminate. It was (double-circle) when the contamination property of the obtained laminated body was evaluated.

  The polyolefin resin film of the present invention is useful as a protective film requiring high quality, for example, because it has few fish eyes and is excellent in appearance and is also excellent in low contamination.

Claims (5)

A polyolefin resin film, wherein the amount of radical scavenger is 0.1 to 3 ppm and the number of fish eyes of 50 μm or more is 10 / m ² or less. The polyolefin resin according to claim 1, wherein the polyolefin resin is at least one polyolefin resin selected from the group consisting of polyethylene, an ethylene-vinyl acetate copolymer, and a saponified product of an ethylene-vinyl acetate copolymer. Resin film. ^3. The polyolefin resin film according to claim 1, wherein when the polyolefin resin film is a polyethylene film, the density is 931 to 936 kg / m ³ . It is manufactured from a step of preparing a polyolefin solution by dissolving a polyolefin resin in a solvent, and subsequently a step of continuously casting the polyolefin solution on a substrate and then evaporating the solvent by heating. The polyolefin resin film according to any one of claims 1 to 3. A laminate comprising the polyolefin resin film according to any one of claims 1 to 4.