WO2009139439A1 - Polyolefin resin manufacturing method, polyolefin resin, and solution and film thereof - Google Patents

Abstract

Disclosed are a polyolefin resin manufacturing method that comprises a step in which a polyolefin solution is prepared by dissolving a polyolefin resin in a halogenated hydrocarbon solvent, or a non‑halogen solvent selected from an aliphatic hydrocarbon, aromatic hydrocarbon, ether compound, or acetal compound with a boiling point of 70 to 140ºC and a solvency index of 13 to 20 MPa^1/2, and a step in which the halogenated hydrocarbon solvent or the non‑halogen solvent is then evaporated from the solution, and a polyolefin resin manufacturing method that includes a step in which a polyolefin solution is prepared by dissolving a polyolefin resin in a halogenated hydrocarbon solvent, or the aforementioned non‑halogen solvent, a step in which the solvent is then cooled to cause the polyolefin resin to precipitate, and a step in which the halogenated hydrocarbon solvent or the non‑halogen solvent is then evaporated. The resulting polyolefin resin yields a high‑quality film with reduced visible defects, such as fish‑eye deformation, etc.

Description

Method for producing polyolefin resin, polyolefin resin, solution and film thereof

The present invention relates to a method for producing a polyolefin resin, a polyolefin resin, a solution thereof, and a film.

Polyolefin resins are used in a wide range of industrial fields because they are excellent in economy, mechanical strength, transparency, moldability, hygiene, and the like. Polyolefin films are processed into single-layer or multi-layer films, and are widely used in the field of electronic materials including optical masking films. In these applications, the demand for improving the quality of the film has become stricter year by year, and the reduction of fish eyes that reduce the appearance of the film is required. For example, a polyolefin film with very few fish eyes is required for a protective film layer for a dry film resist.
Since fish eyes are generated due to foreign matter and gel mixed in the polyolefin resin, it is necessary to reduce the amount of foreign matter and gel in the polyolefin resin in order to produce a high-quality film.

The term “fish eye” as used herein means that when gel and / or foreign matter is present in the film, the gel and / or foreign matter has an optically non-uniform state by exhibiting a refractive index different from its surroundings. It means what is recognized. Such non-uniformity of the refractive index occurs when the gel and / or foreign matter itself has a refractive index different from the refractive index of the film itself. It affects fluidity and may cause optical non-uniformity in areas that are larger than the size of the gel and / or foreign material itself. In this case, the optical strain is defined not as the size of the gel and / or the foreign material itself, but as the size of the region causing the optical strain including the surrounding region.

In the present invention, “gel” refers to an uncrosslinked component that has not been sufficiently plasticized in the process of producing a polyolefin resin, and a component that has been crosslinked by a thermal history applied to the polyolefin resin. The presence of the gel causes the above-mentioned optical distortion in the film and significantly deteriorates the appearance of the film. Further, the “foreign matter” is a substance other than the polyolefin resin mixed from the outside in the process of producing the polyolefin resin or the process of forming the polyolefin into a film, and examples thereof include fibers, inorganic substances, and metals.

It is known that the gel in the polyolefin resin includes an unmelted gel and a crosslinked gel. The crosslinked gel is a gel in which the 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. However, when melt-kneaded by a normal single-screw or twin-screw extruder and extruded from a die or the like, the state as an unmelted gel is maintained. The ratio is high, causing fish eyes to be produced and the appearance of the product to deteriorate.

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, or low-density polyethylene, have a large amount of the above-mentioned uncrosslinked gel and crosslinked gel. It has been known. In the high-temperature reactor, hydrogen is radically extracted from the produced polymer and branches are formed. This branched polymer generates a crosslinked gel by causing a high-pressure separator connected to the reactor and an uncrosslinked gel as an aggregate in the process of being exposed to high temperature in the process of pelletization or a crosslinking reaction.

As a method for suppressing the formation of gel, for example, a method for producing a polyethylene resin having a low gel content by polymerizing ethylene in the presence of an antistatic agent has been proposed (see Patent Document 1). . However, it was impossible to completely suppress the formation of gel, and it was necessary to select a resin having as little gel content as possible from the manufactured resin, which was an economical problem.

Japanese Examined Patent Publication No. 63-41926

On the other hand, a method for improving the appearance of the product by removing the crosslinked gel and the uncrosslinked gel contained in the resin during molding has been used. For example, a method of installing a filtration device in a single or twin screw extruder is known, and a metal mesh, a sintered metal filter, or the like is used as a filter medium. Such a filtration method is extremely effective for removing the cross-linked gel. However, since the unmelted gel is easily deformed and easily passes through the filter medium, it is difficult to remove it efficiently and effectively. there were.

The present invention has been made in view of the above problems, and its object is to provide a method for producing a polyolefin resin useful for producing a high-quality film in which defects in appearance such as fish eyes are reduced. There is to do.

As a result of intensive studies, the present inventors have found that a polyolefin resin produced by dissolving a polyolefin resin in a specific solvent and then evaporating the solvent is a high-quality polyolefin film free from defects in appearance such as fish eyes. And the present invention has been completed.

Thus, according to the present invention, the polyolefin resin is a halogenated hydrocarbon solvent, or an aliphatic hydrocarbon, aromatic hydrocarbon, ether having a boiling point of 70 to 140 ° C. and a solubility index of 13 to 20 MPa ^1/2. A step of preparing a polyolefin solution by dissolving in at least one non-halogen solvent selected from a compound and an acetal compound, and a step of evaporating the halogenated hydrocarbon solvent or the non-halogen solvent from the solution. A method for producing a polyolefin resin (hereinafter sometimes referred to as “first production method”) is provided.

Furthermore, according to the present invention, the polyolefin resin may be a halogenated hydrocarbon solvent or an aliphatic hydrocarbon, aromatic hydrocarbon, ether having a boiling point of 70 to 140 ° C. and a solubility index of 13 to 20 MPa ^1/2. A step of preparing a polyolefin solution by dissolving in at least one non-halogen solvent selected from a compound and an acetal compound, a step of subsequently cooling the solution to precipitate a polyolefin resin, and further, from the precipitated polyolefin resin, There is provided a method for producing a polyolefin resin (hereinafter sometimes referred to as “second production method”), which comprises a step of evaporating a halogenated hydrocarbon solvent or the non-halogen solvent.

According to the present invention, in order to reduce the uncrosslinked gel, it is difficult to eliminate the aggregated state by ordinary melt processing. Therefore, the aggregated state of the uncrosslinked gel causing the fish eye is This can be eliminated by using a hydrofluoric solvent or a specific non-halogen solvent. That is, the polyolefin resin containing uncrosslinked gel is solvated in a halogenated hydrocarbon solvent or a specific non-halogen solvent in which the polyolefin resin is dissolved, and the polymer aggregate is brought into a non-aggregated state. By this operation, the polymer chain is stabilized in the solvent, and even if it is solidified again, it does not return to the originally held aggregated structure, and fish eyes are not generated.
Therefore, the polyolefin resin produced by the method of the present invention gives a high-quality film in which defects in appearance such as fish eyes are greatly reduced.

Hereinafter, the present invention will be described in detail.
In the first polyolefin resin production method of the present invention, a polyolefin resin is a halogenated hydrocarbon solvent or an aliphatic hydrocarbon or aromatic hydrocarbon having a boiling point of 70 to 140 ° C. and a solubility index of 13 to 20 MPa ^1/2. A step of preparing a polyolefin solution by dissolving in at least one non-halogen solvent selected from a hydrocarbon, an ether compound and an acetal compound, and a step of evaporating the halogenated hydrocarbon solvent or the non-halogen solvent from the solution; including.

Each step will be described below.
1) Dissolution process The “polyolefin resin” used in the production method of the present invention is not particularly limited. In the present invention, the term “polyolefin resin” refers to a homopolymer of an α-olefin having 2 to 10 carbon atoms, a copolymer of the olefins, and another ethylenically unsaturated monomer copolymerizable with the olefin. It refers to a copolymer. Copolymers include both random and block. The content of α-olefin in the copolymer is 50% by weight or more. The polyolefin resin referred to in the present invention further contains a chemically modified product of such an α-olefin homopolymer and copolymer.

Specific examples of the α-olefin include ethylene, propylene, butene, propene and the like. Among these, the production method of the present invention is preferably adapted to ethylene homopolymers and copolymers.
The content of α-olefin in the copolymer is 50% by weight or more, preferably 70% by weight or more. Specific examples of the ethylenically unsaturated monomer copolymerized with the α-olefin include vinyl acetate, methyl acrylate, ethyl acrylate, and methyl methacrylate.

Specific examples of the polyolefin resin include a polyethylene resin. Polyethylene resins include high density polyethylene (HDPE), medium density polyethylene (MDPE), low density polyethylene (LDPE), linear low density polyethylene (L-LDPE), very low density polyethylene (V-LDPE), etc. . Examples of linear low density polyethylene (L-LDPE) include ethylene-α-olefin copolymers such as ethylene-1-butene copolymer, ethylene-1-hexene copolymer, and ethylene-1-octene copolymer. Can be mentioned. Other polyolefin resins include, for example, ethylene-4-methylpentene-1 resin, ethylene-vinyl acetate copolymer (EVA) and saponified products thereof, ethylene-vinyl alcohol resin (EVOH), ethylene-propylene copolymer ( EPM) and the like, polypropylene homopolymer, polypropylene block copolymer, polypropylene random copolymer and the like. Furthermore, modified products such as chlorinated products of these polyolefins can also be used.
These polyolefins can be used alone or in combination.

The polymerization method for synthesizing the polyolefin resin may be a generally known method, and examples thereof include high-pressure radical polymerization, medium-low pressure polymerization, solution polymerization, and slurry polymerization. Examples of the polymerization catalyst include peroxide catalysts, Ziegler-Natta catalysts, metallocene catalysts, and the like. Polyolefins polymerized with these catalysts can be used without any limitation.
The molecular weight of the polyolefin resin used in the production method of the present invention is not limited as long as the polyolefin resin is dissolved in a halogenated hydrocarbon solvent or a specific non-halogen solvent.

The shape of the polyolefin resin used in the production method of the present invention is not limited as long as the polyolefin resin is dissolved in a halogenated halogenated hydrocarbon solvent or a specific non-halogen solvent, but for example, a cylindrical shape obtained by a strand cut method or the like. Examples include pellets, egg-shaped pellets produced by an underwater hot cut method (underwater cut method), amorphous powders, granular materials, granules, and the like. In the case of a resin produced by a slurry method such as high-density polyethylene, the polymer may be taken out from the reactor as a powder. In the present invention, such a powdery polymer is used in the same manner. be able to.

In the production method of the present invention, it is also possible to use a polyolefin resin film, fiber, or molded article once molded as a raw material. In this case, there is no limitation on the shape of the molded article.
By the production method of the present invention, it is possible to produce a molded article in the form of a polyolefin resin, in particular, a powder, a high quality film or the like. By using this polyolefin resin powder, an arbitrary molded body such as a film can be produced by a known molding method described later.

The halogenated hydrocarbon solvent used in the production method of the present invention is not limited as long as the polyolefin resin dissolves. Specific examples of halogenated hydrocarbons include 1,1-dichloroethane, 1,2-dichloroethane, methylene chloride, chloroform, 1,1,1-trichloroethane, 1,1,2-trichloroethane, carbon tetrachloride, trichloroethylene, Chlorinated solvents such as chloroethylene, brominated solvents such as ethane bromide, fluorinated solvents such as monofluorobenzene, 1,4-difluorobenzene, perfluoroheptane, perfluorooctane, dichloropentafluoropropane, bromochloromethane, Examples include a solvent containing bromine and fluorine such as 1,2-dibromo-1,1-difluoroethane. These halogenated hydrocarbon solvents can be used in combination of two or more.

Among these halogenated hydrocarbon solvents, a polyolefin resin, for example, a halogenated hydrocarbon solvent capable of dissolving at 80 to 110 ° C. is suitable, and from the viewpoint of evaporation of the solvent, a halogenated hydrocarbon having a low boiling point. Solvents are suitable. From such a viewpoint, 1,1,2-trichloroethane is most preferable.

The non-halogen solvent used in the production method of the present invention is a material that does not contain halogen, and has a boiling point of 70 to 140 ° C. and a solubility index of 13 to 20 MPa ^1/2 , an aliphatic hydrocarbon or an aromatic hydrocarbon At least one selected from ether compounds and acetal compounds (hereinafter simply referred to as “non-halogen solvents”) is used. When the boiling point is less than 70 ° C., it is difficult to dissolve the polyolefin at normal pressure or low pressure. On the other hand, when the boiling point exceeds 140 ° C., there is a problem because the energy cost for evaporating the solvent increases. It is. On the other hand, when the solubility index is out of the range of 13 to 20 MPa ^1/2 , it becomes difficult to dissolve the polyolefin resin in the solvent.

Non-halogen solvents other than aliphatic hydrocarbons, aromatic hydrocarbons, ether compounds and acetal compounds (hereinafter simply referred to as “other non-halogen solvents”, for example, ketone compounds such as methyl ethyl ketone, diisopropyl ketone, and diethyl ketone, acetonitrile Nitrile compounds such as benzonitrile, alcohol compounds such as 1-butanol, isopropanol and 2-methyl-2-butanol, and amine compounds such as triethylamine and ethylenediamine) have a boiling point of 70 to 140 ° C. and a solubility index of 13 to 20 MPa. Even if it is ^1/2 , it becomes difficult to dissolve the polyolefin resin in the solvent.

Non-halogen solvents having a boiling point of 70 to 140 ° C. and a solubility index of 13 to 20 MPa ^1/2 include, for example, 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 Such as aliphatic hydrocarbons such as benzene, toluene, m-xylene, p-xylene, ethylbenzene, ether compounds such as cyclopentyl methyl ether, ethyl amino ether, dioxane, dipropyl ether, diethyl acetal, etc. Acetal compound Illustrated. These non-halogen solvents can be used as a mixture of two or more, and the ratio is not particularly limited. The non-halogen solvent preferably has a hydrogen bond term (δh) in the solubility index of 5 MPa ^1/2 or less in order to make the polyolefin resin solution in a uniform dissolved state.

Among these non-halogen solvents, from the viewpoint of the balance between the solubility of the polyolefin resin and the suppression of thermal degradation, a non-halogen solvent that can dissolve the polyolefin resin at, for example, 80 to 120 ° C. is preferable. From the viewpoint of transpiration, a non-halogen solvent having a low boiling point is preferred. From such a viewpoint, n-heptane, methylcyclohexane, toluene, and cyclopentylmethyl ether are preferably used.

The non-halogen solvent is at least one selected from aliphatic hydrocarbons, aromatic hydrocarbons, ether compounds and acetal compounds, but contains other non-halogen solvents as long as the effects of the present invention are not impaired. May be. When the other non-halogen solvent is contained, the weight ratio of the non-halogen solvent to the other non-halogen solvent varies depending on the other non-halogen solvent to be contained, and examples thereof include 70 to 99:30 to 1.

In the step of preparing the polyolefin resin solution, the melting temperature of the polyolefin resin is appropriately determined depending on the halogenated hydrocarbon solvent or non-halogen solvent used and the polyolefin resin, and the melting temperature is 60 to 200 ° C. It is preferable from an economic point of view to dissolve at a normal pressure or lower than the boiling point of the solvent. When the polyolefin resin is difficult to dissolve, it can be dissolved at a temperature equal to or higher than the boiling point of the solvent using a pressure resistant vessel, if necessary. The dissolution time is 20 minutes to 8 hours, although it depends on the shape of the polyolefin resin and the dissolution temperature. 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. However, stirring during dissolution is not essential. Moreover, the reactor used for melt | dissolution does not ask | require the shape etc., such as a vessel, a tube, a horizontal reactor, an extruder.

The polyolefin solution prepared by dissolving the polyolefin resin in a halogenated hydrocarbon solvent or a non-halogen solvent is preferably filtered in a state where the polyolefin is dissolved in order to further remove foreign substances in the polyolefin resin. As a filtration method, a known method can be used. For example, a metal woven fabric (mesh), a metal sintered filter known by a common name of a polymer filter, a metallic nonwoven fabric, polypropylene, a fluororesin, etc. Nonwoven fabrics using molecular materials are exemplified. These filter media can be used singly or in combination, and the filtration can be performed in multiple stages in order to sequentially increase the filtration accuracy.

In the filtration method using a polymer filter, a polymer filter using a cylindrical filter called a pleat type or a candle type, a cylinder type, or a leaf disk type polymer filter in which a large number of disk filters are combined may be used. it can. It is also possible to use a pleated type or a composite type polymer filter in which candle type and leaf disc type filters are installed in the same filter container. The filter medium is not particularly limited, and a sintered wire mesh, a sintered metal nonwoven fabric, and a sintered metal powder filter medium can be used.

Since it is introduced into the concentrator, the accuracy when filtering a low-viscosity polymer solution is preferably as high as possible, and a filter in the range of 0.5 to 200 μm is suitably used. The filtration temperature is not particularly limited as long as it is not higher than the boiling point of the solvent used. It is preferable to select the viscosity, flow rate, pressure, and filter medium of the polymer solution so that the filtration efficiency is at least 95% or more, more preferably 99% or more. In addition to the polymer filter, a plate tube type or plate pleat type line filter using a sintered metal mesh as a filter medium can be used.

If the polyolefin solution is insufficiently filtered once, it can be further divided into two portions. For example, after the polyolefin solution is filtered with a pleat-type filter, a high-viscosity polyolefin solution obtained by concentrating the polyolefin solution by the above-described concentration method can be filtered again with a leaf filter having high filtration accuracy.
The concentration of the polyolefin solution is not particularly limited and needs to be appropriately set depending on the selected solvent, but a concentration of 0.1 to 50% by weight is used.

In dissolving the above polyolefin resin, various additives can be added within a range that does not affect the fish eye, appearance, and physical properties of the film. For example, various additives such as wax can be added, including single or plural antioxidants selected from phenol, phosphorus, sulfur and the like.
The polyolefin solution obtained as described above becomes an unstretched film having 10 or less / m ² of fish eyes of 50 μm or more.

2) Solvent transpiration step As a method for evaporating the halogenated hydrocarbon solvent or the non-halogen solvent in the first production method of the present invention, for example, spraying a polyolefin solution by spray drying under reduced pressure to form a powder. A dry method can be used. In spray drying of a polyolefin solution, a halogenated hydrocarbon solvent or a non-halogen solvent is evaporated from a polyolefin solution that has been made into droplets by discharging the polyolefin solution from a small-bore nozzle into a heated vacuum container as necessary. It is something to be made. The degree of vacuum in this case is appropriately selected depending on the selected halogenated hydrocarbon solvent or non-halogen solvent and the temperature of the vacuum vessel. As long as the polyolefin solution becomes droplets and the halogenated hydrocarbon solvent or non-halogen solvent evaporates from the droplets, there are no restrictions on the degree of vacuum and temperature. Usually, the degree of vacuum is in the range of 0.1 to 200 Torr, and the temperature is 20 to 180 ° C.
The obtained polyolefin resin powder can be formed into a high-quality film by using, for example, inflation molding, a single-screw or twin-screw extruder equipped with a T-die, but there is no limitation on the molding method. Absent.

As another method of evaporating the halogenated hydrocarbon solvent or the non-halogen solvent in the first production method of the present invention, for example, a polyolefin solution is continuously cast on a substrate to form a thin film, and then heated. A drying method can be used. As the base material, various polymer films typified by polyester films such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), and surface treatment of these polyester films with silicon treatment, hard coating such as acrylic resin, etc. Examples include various films applied, metal foils such as aluminum, copper, and stainless steel, various metal materials such as metal films and metal sheets, and various polymer films such as PET subjected to metal vapor deposition. Furthermore, those obtained by applying a polymer coating or an inorganic coating on these metal materials can be used as necessary. Further, it can be cast on a heated rotating metal drum as necessary, and can be coated on an endless polymer belt or metal belt.

Examples of the method for casting a polyolefin solution on a substrate include known methods such as a gravure coater, comma coater, die coater, double Mayer bar coater and the like. When heating is necessary to dissolve the polyolefin resin and the boiling point of the solvent is low, in order to suppress an increase in the viscosity of the polyolefin solution due to rapid volatilization of the halogenated hydrocarbon solvent or non-halogen solvent in the casting process A die coater or a double Mayer bar coater is preferably used. The thickness of the polyolefin solution on the substrate immediately after being formed by casting is 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.

The polyolefin solution layer formed on the substrate can be dried in one step to multiple steps, and the temperature range is 50 to 200 ° C. When drying in multiple steps, the temperature is 50 to 100 ° C. A method such as primary drying and secondary drying in the range of 100 to 200 ° C. can be employed. 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 may be peeled off from the substrate after sufficient drying and wound up, or peeled off from the substrate in the middle of drying, and only the polyolefin resin layer may be dried and wound up to form a film. it can.

The second polyolefin resin production method of the present invention includes a step of preparing a polyolefin solution by dissolving a polyolefin resin in a halogenated hydrocarbon solvent or a non-halogen solvent, and subsequently cooling the solution to obtain a polyolefin resin. And a step of evaporating the halogenated hydrocarbon solvent.
The melting step is the same as that described above for the first manufacturing method, and the other steps will be described below.

2) Cooling step After the dissolving step, the polyolefin solution is cooled to precipitate a polyolefin resin. The cooling rate of the solution obtained by dissolving the polymer is not particularly limited, but is preferably 0.5 to 30 ° C./min in order to reduce production efficiency and equipment cost. By cooling the solution, polyolefin precipitates. The shape of the precipitated solid may be substantially a block shape or a granular shape.

3) Solvent transpiration step The solidified polyolefin is separated from the solvent by a known method such as decantation, and then the solvent in the solid is removed to obtain a dried polymer. The drying temperature at this time is from room temperature to 150 ° C., and the pressure is from 0.1 Torr to normal pressure. The drying time varies depending on the solid form obtained and the drying apparatus used, and is 1 minute to 40 hours. The solid thus obtained can be pulverized and shaped at a low temperature as necessary, and molded by a known molding method such as a melt extrusion method or an inflation molding method.

In the production method of the present invention, a polyolefin solution obtained by dissolving a polyolefin resin in a halogenated hydrocarbon solvent or the above-mentioned non-halogen solvent has a small gel and / or foreign matter content and is usually 20 μm thick. When an unstretched film is used, the number of fish eyes having a major axis of 50 μm or more is 10 or less / m ² .

The polyolefin resin obtained by the production method of the present invention usually has a gel having a major axis of 50 μm or more and a foreign matter content of 10 or less per 20 g. More preferably, the content of gel and foreign matters having a major axis of 50 μm or more is 5 or less / 20 g, particularly preferably 3 or less / 20 g, and most preferably 1 or less / 20 g.

The film made of the polyolefin resin obtained by the production method of the present invention is usually an unstretched film having a thickness of 20 μm, and fish eyes having a major axis of 50 μm or more are 10 or less / m ² , preferably 5 or less / m ² , More preferably 3 pieces / m ² or less, most preferably 1 piece or less / m ² .
Since the polyolefin resin film has few fish eyes, it can be used, for example, as a protective film for dry film photoresists that require high quality. A film for dry film resist is required to have high flatness. The thickness of the film is preferably 10 to 50 μm, and the thickness accuracy is preferably 2 μm or less.

Hereinafter, the present invention will be described in more detail based on examples, but these are examples for helping understanding of the present invention, and the present invention is not limited by these examples.

<Polyolefin resin>
(1) EVA (ethylene / vinyl acetate copolymer)
Ultrasen (registered trademark) 05A57C (MFR = 15 g / 10 min, density = 929 kg / m ³ ), manufactured by Tosoh Corporation (2) L-LDPE (linear low density polyethylene, ethylene / hexene copolymer)
Nipolon-Z (registered trademark) TZ420 (MFR = 10 g / 10 min, density = 913 kg / m ³ ), Tosoh Corporation L-LDPE1 (MFR = 4 g / 10 min, density = 900 kg / m ³ )
L-LDPE2 (MFR = 4 g / 10 min, density = 923 kg / m ³ )
(3) LDPE (low density polyethylene)
Petrocene (registered trademark) 225 (MFR = 3.7 g / 10 min, density = 923 kg / m ³ ), manufactured by Tosoh Corporation Petrocene (registered trademark) 204 (MFR = 7.0 g / 10 min, density = 922 kg / m ³⁾ ), LDPE1 manufactured by Tosoh Corporation (MFR = 2.0 g / 10 min, density = 924 kg / m ³ )
LDPE2 (MFR = 3.0 g / 10 min, density = 924 kg / m ³ )
LDPE3 (MFR = 3.0 g / 10 min, density = 924 kg / m ³ )
(4) HDPE (high density polyethylene)
Nipolon Hard (registered trademark) 4010, manufactured by Tosoh Corporation (5) PET film Melnex (registered trademark) type S (thickness: 125 μm), manufactured by Teijin DuPont Films, Ltd.

<Fisheye measurement>
Since the fish eye having a major axis of 50 μm or more can be visually confirmed, the obtained unstretched film having a thickness of 15 to 50 μm is irradiated from the back surface using a fluorescent lamp, and the fish eye in a 5 m long film is visually measured. It was calculated as the number per 1 m ² .

<Measurement of gel and foreign matter>
The number of gels and foreign matters per 20 g of resin was calculated from the number per 1 m ^{2 of} unstretched film of fish eyes having a major axis of 50 μm or more.
<Measurement of film thickness>
A film thickness measuring device K-402B manufactured by Anritsu Corporation was used.

<Casting>
The coating was performed using a coating machine provided with a die having a width of 300 mm and a heat of 600 mm. The polymer solution dissolved in the autoclave was transferred to a tank equipped with a heating jacket in a pressurizable tank equipped with a 5 L-scale 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 was 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 was adjusted using HST-120CT manufactured by Mysec Co., Ltd. . In Examples 1 to 15, the roll holding the film close to the die is heated from the back using a halogen heater (model IRE182-N) manufactured by Iwasaki Electric Co., Ltd., and the temperature depends on the voltage applied to the halogen heater. Adjusted.

<Deposition machine>
Toyo Seiki Seisakusho Co., Ltd. 100C100 type lab plast mill is connected to Toyo Seiki Seisakusho Co., Ltd. D25-20 type full flight screw and Toyo Seiki Seisakusho Co., Ltd. 250mm wide T-die. A film was formed.

Example 1
3.2 kg of EVA pellets and 20 L of 1,1,2-trichloroethane (28.8 kg) were charged into a 30 L autoclave and dissolved under heating at 110 ° C. for 1 hour with stirring to obtain a polyolefin solution (EVA solution). It was. 3 L of this solution was transferred to a 5 L tank heated to 90 ° C., and transferred to a heated 300 mm-wide coating die through a Teflon (registered trademark) hose with a heating jacket maintained at 80 ° C. The solution was continuously cast on a polyethylene naphthalate (PEN) film as a base material from a die pressurized in a tank and maintained at 90 ° C. The speed of the PEN film was set to 3 m / min. The film on the substrate was dried at 100 ° C., and the obtained unstretched film having a thickness of 21.5 μm was peeled from the PEN film, and the fish eye of the unstretched film was measured. As a result, the number of fish eyes of 50 μm or more was 1 / m ² , and it was confirmed that an excellent quality film was obtained. Moreover, from this result, EVA was 50 μm or more of gel and foreign matter / 20 g.

Example 2
L-LDPE Nipolon-Z (registered trademark) TZ420 pellets 2.5 kg and 1,1,2-trichloroethane 20 L (28.8 kg) were charged into a 30 L autoclave and dissolved with stirring at 110 ° C. for 1 hour. To obtain a solution of L-LDPE. 3 L of this solution was transferred to a 5 L tank heated to 100 ° C., and transferred to a 300 mm wide coating die through a Teflon (registered trademark) hose with a heating jacket maintained at 100 ° C. The tank was pressurized and the solution was cast on a PEN film as a substrate from a die maintained at 100 ° C. The speed of the PEN film was set to 3 m / min. The film on the substrate was dried at 100 ° C., and the obtained unstretched film having a thickness of 22 μm was peeled from the PEN film, and the fish eye of the unstretched film was measured. As a result, the number of fish eyes of 50 μm or more was 0.4 / m ² , and it was confirmed that an excellent quality film was obtained. Further, from this result, L-LDPE was found to have a gel of 50 μm or more and a foreign matter of 1 or less / 20 g.

Examples 3 to 10
A film was obtained in the same manner as in Example 1 except for the polyolefin resin shown in Table 1, its charging amount and the dissolution temperature. Table 1 shows the evaluation results of fish eyes of 50 μm or more of these unstretched films. As a result, the number of fish eyes of 50 μm or more was 0.2-1 piece / m ² , and it was confirmed that an excellent quality film was obtained. From these results, the polyolefin resin had a gel of 50 μm or more and a foreign matter of 1 or less / 20 g.

Example 11
L-LDPE Nipolon-Z (registered trademark) TZ420 pellets 2.5 kg and 1,1,2-trichloroethane 20 L (28.8 kg) were charged into a 30 L autoclave and dissolved with stirring at 110 ° C. for 1 hour. To obtain a solution of L-LDPE. While filtering this solution through a 600 mesh metal mesh, 3 L of the solution was transferred to a 5 L tank heated to 100 ° C. and heated through a Teflon (registered trademark) hose with a heating jacket maintained at 100 ° C. Transferred to width coating die. The tank was pressurized and the solution was cast on a PEN film as a substrate from a die maintained at 100 ° C. The speed of the PEN film was set to 3 m / min. The film on the substrate was dried at 100 ° C., and the obtained unstretched film having a thickness of 22 μm was peeled from the PEN film, and the fish eye of the unstretched film was measured. As a result, the number of fish eyes of 50 μm or more was 0.1 / m ² , and it was confirmed that an excellent quality film was obtained. Further, from this result, L-LDPE had a gel of 50 μm or more and a foreign matter of 1 or less / 20 g.

Example 12
LDPE1 pellets 2.5 kg and 1,1,2-trichloroethane 20 L (28.8 kg) were charged into a 30 L autoclave and dissolved under heating at 110 ° C. for 2 hours with stirring to obtain an LDPE solution. This solution was filtered through a 200-mesh metal mesh, 3 L was transferred to a 5 L tank heated to 100 ° C., and heated through a Teflon (registered trademark) hose with a heating jacket maintained at 100 ° C. Transferred to width coating die. The tank was pressurized and the solution was cast from a die maintained at 110 ° C. onto a 188 μm thick PET film as a substrate. At this time, the temperature of the back roll around which the base film was wound was set to 75 ° C., and the speed of the PET film was set to 1.5 m / min. The film on the substrate was dried at 100 to 160 ° C., and the resulting unstretched film having a thickness of 22 μm was peeled from the PET film, and the fish eye of the unstretched film was measured. As a result, the number of fish eyes of 50 μm or more was 0.02 / m ² , and it was confirmed that an excellent quality film was obtained. Further, from this result, LDPE had a gel of 50 μm or more and a foreign substance of 1 or less / 20 g.

Example 13
The EVA solution obtained in Example 1 was powdered by a spray drying method. A film having a thickness of 50 μm and a width of 250 mm was obtained from this powder using a Laboplast mill equipped with a T-die having a width of 15 cm at 180 ° C. and a single screw extruder. As a result of measuring the fish eyes of the obtained unstretched film, it was confirmed that the fish eyes of 50 μm or more were excellent at 0.5 pieces / m ² . Moreover, from this result, EVA was 50 μm or more of gel and foreign matter / less than 1 piece / 20 g.

Example 14
The polyolefin solution obtained by the same method as in Example 12 was cooled for 1 day to precipitate a polymer, which was separated from tetrachloroethane as a solvent. After removing the solvent by decantation, the solidified bulk polymer was dried at 40 ° C. for 48 hours to obtain 2.490 kg of a white solid. This solid was extruded at a lab plast mill, a cylinder temperature of 190 ° C. and a die temperature of 190 ° C. to obtain a film having a thickness of 50 μm. As a result of measuring the fish eyes of this unstretched film, it was confirmed that the number of fish eyes of 50 μm or more was 1 / m ² and was excellent in quality. Moreover, from this result, LDPE was 1 gel / 20g of gel and foreign material of 50 micrometers or more.

Example 15
A 30 L autoclave was charged with 2.5 kg of L-LDPE Nipolon-Z (registered trademark) TZ420 pellets and 20 L of perchlorethylene and dissolved under heating at 110 ° C. for 1 hour with stirring to obtain a solution of L-LDPE. . 4 L of this solution was transferred to a 5 L tank heated to 100 ° C., and transferred to a 300 mm wide coating die through a Teflon (registered trademark) hose with a heating jacket maintained at 100 ° C. The tank was pressurized, and the solution was cast on a PET film as a substrate from a die maintained at 105 ° C. The speed of the PET film was set at 3 m / min. The film on the substrate was dried at 100 to 140 ° C., and the obtained film was peeled from the PET film, and the fish eye of the unstretched film was measured. As a result, the number of fish eyes of 50 μm or more was 0.5 / m ² , and it was confirmed that an excellent quality film was obtained. Further, from this result, L-LDPE had a gel of 50 μm or more and a foreign matter of 1 or less / 20 g.

Comparative Example 1
EVA pellets were obtained at 180 ° C. using a Laboplast mill equipped with a T-die having a width of 15 cm and a single screw extruder, and having a thickness of 50 μm and a width of 250 mm. The obtained unstretched film had 90 / m ² fish eyes of 100 μm or more, and the film quality was low. Moreover, from this result, EVA contained a large number of gels and foreign substances of 100 μm or more.

Comparative Examples 2-10
A film was obtained in the same manner as in Comparative Example 1 except for the polyolefin resin and temperature shown in Table 2. Table 2 shows the evaluation results of fish eyes of 50 μm or more of these unstretched films. As a result, many fish eyes of 70 to 100 μm were contained, and the quality was inferior. From these results, the polyolefin resin contained a large number of gels and foreign matters of 70 to 100 μm.

Example 16
3.2 kg of EVA pellets and 20 L (15.4 kg) of methylcyclohexane (boiling point: 100.9 ° C., solubility index: 16.0 MPa ^1/2 ) were charged into a 30 L autoclave and stirred at 95 ° C. for 1 hour under heating. The resulting solution was dissolved to obtain a polyolefin solution (EVA solution). 3 L of this solution was transferred to a 5 L tank heated to 95 ° C., and transferred to a heated 600 mm coating die through a Teflon (registered trademark) hose with a heating jacket maintained at 90 ° C. The tank was pressurized, and the solution was cast on a PET film as a substrate from a die maintained at 90 ° C. The speed of the PET film was set at 3 m / min. The film on the substrate was dried at 140 ° C., and the obtained unstretched film having a thickness of 20 μm was peeled from the PET film, and the fish eyes of the unstretched film were measured. As a result, the number of fish eyes of 50 μm or more was 0 / m ² , and it was confirmed that an excellent quality film was obtained. Further, from this result, EVA was 0/20 g of gels and foreign matters of 50 μm or more.

Example 17
Charge 2.5 kg of Nipolon-Z (registered trademark) TZ420 pellets and 20 L (15.4 kg) of methylcyclohexane to a 30 L autoclave and dissolve them under heating at 95 ° C. for 1 hour with stirring to obtain a polyolefin solution (L-LDPE). Solution). 3 L of this solution was transferred to a 5 L tank heated to 95 ° C., and transferred to a heated 600 mm coating die through a Teflon (registered trademark) hose with a heating jacket maintained at 90 ° C. The tank was pressurized and the solution was cast from a die maintained at 100 ° C. onto a PET film as a substrate. The speed of the PET film was set at 3 m / min. The film on the substrate was dried at 140 ° C., and the obtained unstretched film having a thickness of 20 μm was peeled off from PET, and the fish eye of the unstretched film was measured. As a result, the number of fish eyes of 50 μm or more was 0.5 / m ² , and it was confirmed that an excellent quality film was obtained. Further, from this result, L-LDPE had a gel of 50 μm or more and a foreign matter of 1 or less / 20 g.

Example 18
LDPE1 pellets 2.5 kg and methylcyclohexane 20 L (15.4 kg) were charged into a 30 L autoclave and dissolved under heating at 95 ° C. for 2 hours with stirring to obtain a polyolefin solution (LDPE solution). This solution was filtered through a 200-mesh metal mesh, 3 L was transferred to a 5 L tank heated to 100 ° C., and heated through a Teflon (registered trademark) hose with a heating jacket maintained at 95 ° C. Transferred to width coating die. The tank was pressurized and the solution was cast on a PET film as a substrate from a die maintained at 95 ° C. At this time, the speed of the PET film was set to 1.5 m / min. The film on the substrate was dried at 160 ° C., and the obtained unstretched film having a thickness of 20 μm was peeled from the PET film, and the fish eye of the unstretched film was measured. As a result, the number of fish eyes of 50 μm or more was 0.1 / m ² , and it was confirmed that an excellent quality film was obtained. Further, from this result, LDPE had a gel of 50 μm or more and a foreign substance of 1 or less / 20 g.

Example 19
3.2 kg of EVA pellets and 20 L (17.4 kg) of toluene (boiling point: 110.6 ° C., solubility index: 18.0 MPa ^1/2 ) were charged into a 30 L autoclave and stirred at 100 ° C. for 1 hour under heating. To obtain a polyolefin solution (EVA solution). 3 L of this solution was transferred to a 5 L tank heated to 100 ° C., and transferred to a 600 mm wide coating die through a Teflon (registered trademark) hose with a heating jacket maintained at 100 ° C. The tank was pressurized and the solution was cast from a die maintained at 100 ° C. onto a PET film as a substrate. The speed of the PET film was set at 3 m / min. The film on the substrate was dried at 140 ° C., and the obtained unstretched film having a thickness of 20 μm was peeled from the PET film, and the fish eyes of the unstretched film were measured. As a result, the number of fish eyes of 50 μm or more was 0.2 / m ² , and it was confirmed that an excellent quality film was obtained. Moreover, from this result, EVA was 50 μm or more of gel and foreign matter / less than 1 piece / 20 g.

Example 20
LDPE2 pellets 2.5 kg and toluene 20 L (17.4 kg) were charged into a 30 L autoclave and dissolved under heating at 110 ° C. for 2 hours with stirring to obtain a polyolefin solution (LDPE solution). This solution was filtered through a 200-mesh metal mesh, 3 L was transferred to a 5 L tank heated to 110 ° C., and heated through a Teflon (registered trademark) hose with a heating jacket maintained at 105 ° C. Transferred to width coating die. The tank was pressurized, and the solution was cast on a PET film as a substrate from a die maintained at 105 ° C. At this time, the speed of the PET film was set to 1.5 m / min. The film on the substrate was dried at 160 ° C., and the obtained unstretched film having a thickness of 20 μm was peeled from the PET film, and the fish eye of the unstretched film was measured. As a result, the number of fish eyes of 50 μm or more was 0.1 / m ² , and it was confirmed that an excellent quality film was obtained. Further, from this result, LDPE had a gel of 50 μm or more and a foreign substance of 1 or less / 20 g.

Example 21
LDPE3 pellets 2.5 kg and toluene 20 L (17.4 kg) were charged into a 30 L autoclave and dissolved under heating at 105 ° C. for 2 hours with stirring to obtain a polyolefin solution (LDPE solution). This solution was filtered through a 200-mesh metal mesh, 3 L was transferred to a 5 L tank heated to 105 ° C., and heated through a Teflon (registered trademark) hose with a heating jacket held at 105 ° C. Transferred to width coating die. The tank was pressurized, and the solution was cast on a PET film as a substrate from a die maintained at 105 ° C. At this time, the speed of the PET film was set to 1.5 m / min. The film on the substrate was dried at 160 ° C., and the obtained unstretched film having a thickness of 20 μm was peeled from the PET film, and the fish eye of the unstretched film was measured. As a result, the number of fish eyes of 50 μm or more was 0.1 / m ² , and it was confirmed that an excellent quality film was obtained. Further, from this result, LDPE had a gel of 50 μm or more and a foreign substance of 1 or less / 20 g.

Example 22
Charge 3.2 kg of EVA pellets and 20 L (17.4 kg) of toluene into a 30 L autoclave, dissolve uniformly with stirring at 100 ° C. for 1 hour, and then cool until the liquid temperature reaches 90 ° C. A polyolefin solution (EVA solution) was obtained. 3 L of this solution was transferred to a 5 L tank heated to 90 ° C., and transferred to a heated 600 mm coating die through a Teflon (registered trademark) hose with a heating jacket maintained at 90 ° C. The tank was pressurized, and the solution was cast on a PET film as a substrate from a die maintained at 90 ° C. The speed of the PET film was set at 3 m / min. The film on the substrate was dried at 140 ° C., and the obtained unstretched film having a thickness of 20 μm was peeled from the PET film, and the fish eyes of the unstretched film were measured. As a result, the number of fish eyes of 50 μm or more was 0 / m ² , and it was confirmed that an excellent quality film was obtained. Moreover, from this result, EVA was 50 μm or more of gel and foreign matter / less than 1 piece / 20 g.

Example 23
3.2 kg of EVA pellets and 20 L (17.2 kg) of cyclopentyl methyl ether (boiling point: 106 ° C., solubility index: 17 MPa ^1/2 ) were charged into a 30 L autoclave and dissolved with stirring at 95 ° C. for 1 hour. To obtain a polyolefin solution (EVA solution). 3 L of this solution was transferred to a 5 L tank heated to 95 ° C. and transferred to a heated 600 mm coating die through a Teflon (registered trademark) hose with a heating jacket maintained at 95 ° C. The tank was pressurized and the solution was cast on a PET film as a substrate from a die maintained at 95 ° C. The speed of the PET film was set at 3 m / min. The film on the substrate was dried at 140 ° C., and the obtained unstretched film having a thickness of 20 μm was peeled from the PET film, and the fish eyes of the unstretched film were measured. As a result, the number of fish eyes of 50 μm or more was 0.1 / m ² , and it was confirmed that an excellent quality film was obtained. Moreover, from this result, EVA was 50 μm or more of gel and foreign matter / less than 1 piece / 20 g.

Example 24
3.2 kg of Nipolon-Z (registered trademark) TZ420 pellets and 20 L (17.2 kg) of cyclopentyl methyl ether were charged into a 30 L autoclave, and dissolved under stirring at 100 ° C. for 1 hour with heating to obtain a polyolefin solution (L- LDPE solution) was obtained. 3 L of this solution was transferred to a 5 L tank heated to 100 ° C., and transferred to a 600 mm wide coating die through a Teflon (registered trademark) hose with a heating jacket maintained at 100 ° C. The tank was pressurized and the solution was cast from a die maintained at 100 ° C. onto a PET film as a substrate. The speed of the PET film was set at 3 m / min. The film on the substrate was dried at 140 ° C., and the obtained unstretched film having a thickness of 20 μm was peeled from the PET film, and the fish eyes of the unstretched film were measured. As a result, the number of fish eyes of 50 μm or more was 0.2 / m ² , and it was confirmed that an excellent quality film was obtained. Further, from this result, L-LDPE had a gel of 50 μm or more and a foreign matter of 1 or less / 20 g.

Example 25
3.2 kg of LDPE1 pellets and 20 L (17.2 kg) of cyclopentyl methyl ether were charged into a 30 L autoclave and dissolved under heating at 100 ° C. for 1 hour with stirring to obtain a polyolefin solution (LDPE solution). 3 L of this solution was transferred to a 5 L tank heated to 100 ° C., and transferred to a 600 mm wide coating die through a Teflon (registered trademark) hose with a heating jacket maintained at 100 ° C. The tank was pressurized and the solution was cast from a die maintained at 100 ° C. onto a PET film as a substrate. The speed of the PET film was set at 3 m / min. The film on the substrate was dried at 140 ° C., and the obtained unstretched film having a thickness of 20 μm was peeled from the PET film, and the fish eyes of the unstretched film were measured. As a result, the number of fish eyes of 50 μm or more was 0.1 / m ² , and it was confirmed that an excellent quality film was obtained. Further, from this result, LDPE had a gel of 50 μm or more and a foreign substance of 1 or less / 20 g.

Example 26
3.2 kg of Petrocene (registered trademark) 225 pellets and 20 L (17.2 kg) of cyclopentyl methyl ether were charged into a 30 L autoclave and dissolved under heating at 100 ° C. for 1 hour with stirring to obtain a polyolefin solution (LDPE solution). Obtained. 3 L of this solution was transferred to a 5 L tank heated to 90 ° C., and transferred to a heated 600 mm coating die through a Teflon (registered trademark) hose with a heating jacket maintained at 100 ° C. The tank was pressurized and the solution was cast from a die maintained at 100 ° C. onto a PET film as a substrate. The speed of the PET film was set at 3 m / min. The film on the substrate was dried at 140 ° C., and the obtained unstretched film having a thickness of 20 μm was peeled from the PET film, and the fish eyes of the unstretched film were measured. As a result, the number of fish eyes of 50 μm or more was 0.2 / m ² , and it was confirmed that an excellent quality film was obtained. Further, from this result, LDPE had a gel of 50 μm or more and a foreign substance of 1 or less / 20 g.

Example 27
3.2 kg of Petrocene (registered trademark) 204 pellets and 20 L (17.2 kg) of cyclopentyl methyl ether were charged into a 30 L autoclave and dissolved under heating at 100 ° C. for 1 hour with stirring to obtain a polyolefin solution (LDPE solution). Obtained. 3 L of this solution was transferred to a 5 L tank heated to 90 ° C., and transferred to a heated 600 mm coating die through a Teflon (registered trademark) hose with a heating jacket maintained at 100 ° C. The tank was pressurized and the solution was cast from a die maintained at 100 ° C. onto a PET film as a substrate. The speed of the PET film was set at 3 m / min. The film on the substrate was dried at 140 ° C., and the obtained unstretched film having a thickness of 20 μm was peeled from the PET film, and the fish eyes of the unstretched film were measured. As a result, the number of fish eyes of 50 μm or more was 0.1 / m ² , and it was confirmed that an excellent quality film was obtained. Further, from this result, LDPE had a gel of 50 μm or more and a foreign substance of 1 or less / 20 g.

Example 28
Charge 3.2 kg of LDPE1 pellets and 20 L (14.0 kg) of n-octane (boiling point: 125.6 ° C., solubility index: 15.6 MPa ^1/2 ) into a 30 L autoclave and heat at 100 ° C. for 1 hour. A polyolefin solution (LDPE solution) was obtained by dissolving under stirring. 3 L of this solution was transferred to a 5 L tank heated to 100 ° C., and transferred to a 600 mm wide coating die through a Teflon (registered trademark) hose with a heating jacket maintained at 100 ° C. The tank was pressurized and the solution was cast from a die maintained at 100 ° C. onto a PET film as a substrate. The speed of the PET film was set at 3 m / min. The film on the substrate was dried at 160 ° C., and the obtained unstretched film having a thickness of 20 μm was peeled from the PET film, and the fish eye of the unstretched film was measured. As a result, the number of fish eyes of 50 μm or more was 0.3 / m ² , and it was confirmed that an excellent quality film was obtained. Further, from this result, LDPE had a gel of 50 μm or more and a foreign substance of 1 or less / 20 g.

Example 29
The EVA solution obtained in Example 16 was powdered by a spray dry method. An unstretched film having a thickness of 50 μm and a width of 250 mm was obtained from this powder using a Laboplast mill equipped with a T-die having a width of 15 cm at 180 ° C. and a single screw extruder. As a result of measuring the fish eyes of the obtained unstretched film, it was confirmed that 50 μm or more fish eyes were as excellent as 0.3 / m ² . Moreover, from this result, EVA was 50 μm or more of gel and foreign matter / less than 1 piece / 20 g.

Example 30
The LDPE solution obtained by the same method as in Example 18 was cooled over 1 day to precipitate a polymer, which was separated from the solvent methylcyclohexane. After the solvent was removed by decantation, the solidified bulk polymer was vacuum-dried at 40 ° C. for 48 hours to obtain 2.493 kg of a white solid. This solid was extruded at a lab plast mill, a cylinder temperature of 190 ° C. and a die temperature of 190 ° C. to obtain an unstretched film having a thickness of 50 μm. As a result of measuring the fish eye of this unstretched film, the number of fish eyes of 50 μm or more was 0.7 / m ² , and it was confirmed that the film was excellent in quality. Further, from this result, LDPE had a gel of 50 μm or more and a foreign substance of 1 or less / 20 g.

Example 31
LDPE1 pellets 3.2 kg, and cyclopentyl methyl ether 17 L (14.6 kg) and diethyl ketone 3 L (ketone compound, boiling point: 102.2 ° C., solubility index: 18.2 MPa1 / 2) (2.4 kg) in a 30 L autoclave And dissolved with stirring at 100 ° C. for 1 hour to obtain a polyolefin solution (LDPE solution). 3 L of this solution was transferred to a 5 L tank heated to 100 ° C., and transferred to a 600 mm wide coating die through a Teflon (registered trademark) hose with a heating jacket maintained at 100 ° C. The tank was pressurized and the solution was cast from a die maintained at 100 ° C. onto a PET film as a substrate. The speed of the PET film was set at 3 m / min. The film on the substrate was dried at 140 ° C., and the obtained unstretched film having a thickness of 20 μm was peeled from the PET film, and the fish eyes of the unstretched film were measured. As a result, the number of fish eyes of 50 μm or more was 0.2 / m ² , and it was confirmed that an excellent quality film was obtained. Further, from this result, LDPE had a gel of 50 μm or more and a foreign substance of 1 or less / 20 g.

Comparative Example 11
3.2 kg of LDPE1 pellets and 20 L (14.4 kg) of n-nonane (aliphatic hydrocarbon, boiling point: 150.8 ° C., solubility index: 16 MPa ^1/2 ) were charged into a 30 L autoclave and heated at 100 ° C. A polyolefin solution (LDPE solution) was obtained by dissolving for 1 hour under stirring. 3 L of this solution was transferred to a 5 L tank heated to 100 ° C., and transferred to a 600 mm wide coating die through a Teflon (registered trademark) hose with a heating jacket maintained at 100 ° C. The tank was pressurized and the solution was cast from a die maintained at 100 ° C. onto a PET film as a substrate. The speed of the PET film was set at 3 m / min. The film on the substrate was dried at 160 ° C., but the drying was insufficient.

Comparative Example 12
LDPE 1 pellets 3.2 kg and n-hexane (aliphatic hydrocarbon, boiling point: 68.7 ° C., solubility index: 14.9 MPa ^1/2 ) 20 L (13.2 kg) were charged in a 30 L autoclave and heated under 69 Although it melt | dissolved under stirring at 1 degreeC for 1 hour, the uniform solution was not obtained.

Comparative Example 13
LDPE1 pellets 3.2 kg and 1,4-dioxane (ether compound, boiling point: 101 ° C., solubility index: 20.5 MPa ^1/2 ) 20 L (20.7 kg) were charged into a 30 L autoclave and heated at 100 ° C. Although it was dissolved for 1 hour under stirring, a uniform solution was not obtained.

Comparative Example 14
Charge 3.2 kg of pellets of LDPE1 and 20 L (16.1 kg) of methyl ethyl ketone (ketone compound, boiling point: 80 ° C., solubility index: 19 MPa ^1/2 ) into a 30 L autoclave and stir at 80 ° C. for 1 hour with heating. Although dissolved, a uniform solution was not obtained.

Comparative Example 15
Charge 3.2 kg of LDPE1 pellets and 20 L (15.7 kg) of acetonitrile (nitrile compound, boiling point: 82 ° C., solubility index: 24.6 MPa ^1/2 ) into a 30 L autoclave, and stir at 80 ° C. for 1 hour under heating. However, a homogeneous solution was not obtained.

Comparative Example 16
Charge 3.2 kg of LDPE1 pellets and 20 L (16.2 kg) of 1-butanol (alcohol compound, boiling point: 117 ° C., solubility index: 23.1 MPa ^1/2 ) into a 30 L autoclave and heat at 100 ° C. for 1 hour. Although dissolved under stirring, a uniform solution was not obtained.

Comparative Examples 17-25
A film was obtained in the same manner as in Comparative Example 11 except for the polyolefin resin and temperature shown in Table 3. Table 3 shows the evaluation results of fish eyes of 50 μm or more of these unstretched films. As a result, many fish eyes of 70 to 100 μm were contained, and the quality was inferior. From these results, the polyolefin resin contained a large number of gels and foreign matters of 70 to 100 μm.

The polyolefin resin produced by the production method of the present invention is suitable for the production of a high-quality film with significantly reduced fish eyes and has a wide range of applications. Particularly useful applications are protective films for dry film photoresists and thin electronic devices such as flexible solar cells.

Claims (10)

1. The polyolefin resin is a halogenated hydrocarbon solvent or at least selected from an aliphatic hydrocarbon, an aromatic hydrocarbon, an ether compound and an acetal compound having a boiling point of 70 to 140 ° C. and a solubility index of 13 to 20 MPa ^1/2. A polyolefin resin comprising a step of preparing a polyolefin solution by dissolving in one non-halogen solvent, and a step of evaporating the halogenated hydrocarbon solvent or the non-halogen solvent from the solution. Manufacturing method.
2. The method for producing a polyolefin resin according to claim 1, wherein the step of evaporating the halogenated hydrocarbon solvent or the non-halogen solvent comprises spray drying the polyolefin solution under reduced pressure to form powder.
3. 2. The process for producing a polyolefin resin according to claim 1, wherein the step of evaporating the halogenated hydrocarbon solvent or the non-halogen solvent comprises continuously casting a polyolefin solution on a substrate to form a thin film, and then heating. Method.
4. The polyolefin resin is a halogenated hydrocarbon solvent or at least selected from an aliphatic hydrocarbon, an aromatic hydrocarbon, an ether compound and an acetal compound having a boiling point of 70 to 140 ° C. and a solubility index of 13 to 20 MPa ^1/2. A step of preparing a polyolefin solution by dissolving in one kind of non-halogen solvent, and subsequently a step of cooling the solution to precipitate a polyolefin resin. Further, from the precipitated polyolefin resin, the halogenated hydrocarbon solvent or the non-halogen A process for producing a polyolefin resin, comprising a step of evaporating a system solvent.
5. The method for producing a polyolefin resin according to claim 4, wherein the step of evaporating the halogenated hydrocarbon solvent or the non-halogen solvent is performed under heating and / or under reduced pressure.
6. The method for producing a polyolefin resin according to any one of claims 1 to 5, wherein the halogenated hydrocarbon solvent is 1,1,2-trichloroethane.
7. The method for producing a polyolefin resin according to any one of claims 1 to 5, wherein the non-halogen solvent has a hydrogen bond strength term (δh) in a solubility index of 5 MPa ^1/2 or less.
8. The polyolefin resin is a halogenated hydrocarbon solvent or at least selected from an aliphatic hydrocarbon, an aromatic hydrocarbon, an ether compound and an acetal compound having a boiling point of 70 to 140 ° C. and a solubility index of 13 to 20 MPa ^1/2. A polyolefin solution obtained by dissolving in one kind of non-halogen solvent, and having a 20 μm thick unstretched film, the number of fish eyes having a major axis of 50 μm or more is 10 or less / m ² .
9. A polyolefin resin obtained by the production method according to any one of claims 1 to 7, wherein a gel having a major axis of 50 µm or more and foreign matters are 10 or less / 20 g.
10. A film made of a polyolefin resin obtained by the production method according to any one of claims 1 to 7, wherein the number of fish eyes having a major axis of 50 µm or more is 10 or less / m ² in an unstretched film. A film characterized by that.