JP5343694B2 - Polyolefin resin and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyolefin resin useful for producing high quality films with visible defects such as fish-eye being reduced, and to provide a method for producing the same. <P>SOLUTION: A polyolefin resin is provided wherein the number of gels and foreign materials with a size of 50 &mu;m or larger is 10 or less per 20 g. A method for producing the polyolefin resin is also provided which includes a step of preparing a polyolefin solution by dissolving a polyolefin resin in a halogen-based solvent, and a following step of evaporating the halogen-based solvent from the solution. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a polyolefin resin and a method for producing the same.

  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 caused by foreign matters, gels and the like mixed in the polyolefin resin, it is necessary to reduce the amount of foreign matters and gels in the polyolefin resin in order to produce a high quality film.

  The fish eye as used herein refers to a state in which, when a gel or a foreign substance is present in the film, the gel or the foreign substance exhibits an optically non-uniform state by exhibiting a refractive index different from the surroundings. . Such non-uniformity of the refractive index occurs when the gel or foreign matter itself has a refractive index different from the refractive index of the film itself, but these gels and foreign matter also affect the fluidity of the resin during film formation. In some cases, optical non-uniformity may occur in a region larger than the size of the gel and foreign matter itself. In this case, the optical distortion is not defined as the size of the gel or the foreign substance itself, but as an area causing the optical distortion including the surrounding area.

  The gel referred to in the present invention 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, which significantly impairs the film appearance. Further, the foreign matter is a substance other than the polyolefin resin mixed from the outside during the process of manufacturing 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 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, but when melt-kneaded with a normal single- 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 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 many uncrosslinked gels and crosslinked gels. It has been 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 a high-pressure separator connected to the reactor, and an uncrosslinked gel as an agglomerate in the process of being exposed to high temperature in the process of pelletization, or a cross-linked reaction to form a crosslinked gel. It is.

  As a method for solving this problem, for example, a method of producing a resin with a low content of gel and foreign matters has been studied (see, for example, Patent Document 1), but only some of the produced resins are used. Therefore, there was a problem in terms of economy.

JP, 63-41926, A On the other hand, the method of improving the appearance of a product has been used by removing the crosslinked gel and uncrosslinked gel contained in the resin at the time of molding. For example, a method of installing a filtration device in a single-screw or twin-screw extruder is known, and a metal mesh, a sintered metal filter, or the like is used as a filter medium. Although it is extremely effective for removal, the unmelted gel is easily deformed and easily passes through the filter medium, so that it is difficult to remove it efficiently and effectively.

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

  As a result of intensive studies, the present inventors have found that a high-quality polyolefin film can be obtained by using a polyolefin resin obtained by a specific production method, and have reached the present invention. Since the present invention reduces uncrosslinked gel, it is difficult to eliminate the agglomerated state by ordinary melt processing. Therefore, the agglomerated state of the uncrosslinked gel that causes fish eyes is considered to be a halogen-based solvent. It is solved by using. That is, the polyolefin resin containing uncrosslinked gel is solvated in a halogen-based 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 does not return to the originally held aggregate structure until it is solidified again, and fish eyes are not generated. That is, the present invention is a polyolefin resin characterized in that the gel and foreign matter of 50 μm or more is 10 or less / 20g, and a step of preparing a polyolefin solution by dissolving the polyolefin resin in a halogen-based solvent, The present invention relates to a method for producing a polyolefin resin useful for producing a high-quality polyolefin film comprising a step of evaporating a halogen-based solvent from the solution.

  Hereinafter, the present invention will be described in detail.

  The polyolefin resin of the present invention has a gel of 50 μm or more and foreign matters of 10 or less / 20 g. If the polyolefin resin exceeds 10 μg / 20 g of gel and foreign matter having a size of 50 μm or more, the yield as a product is reduced in dry film photoresist applications and the like, and the product cannot be produced economically. In addition, the polyolefin resin itself cannot be used for products with strict quality requirements. The number of gels and foreign matters of 50 μm or more is preferably 5 or less / 20 g, more preferably 3 or less / 20 g, and most preferably 1 or less / 20 g.

  The polyolefin resin of the present invention is not limited at all. For example, the polyethylene resin may be high density polyethylene (HDPE), medium density polyethylene (MDPE), low density polyethylene (LDPE), linear low density polyethylene (L- LDPE) and very low density polyethylene (V-LDPE). 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. Examples of other polyolefin resins include ethylene-4-methylpentene-1 resin, ethylene-vinyl acetate copolymer (EVA) and its saponified product, ethylene-vinyl alcohol resin (EVOH), ethylene-propylene copolymer ( EPM) and the like, polypropylene homopolymers, polypropylene block copolymers, polypropylene random copolymers, and the like, and chlorinated products of these polyolefins. These polyolefin resins may be used alone or as a plurality of selected ones.

  Examples of the method for producing the polyolefin resin of the present invention include a method comprising a step of dissolving a polyolefin resin in a halogen-based solvent to prepare a polyolefin solution, and subsequently a step of evaporating the halogen-based solvent from the solution. It is done.

  Each step will be described below.

1) Dissolution process The polyolefin resin used in the production method of the present invention is not limited at all. For example, polyethylene resins include high-density polyethylene (HDPE), medium-density polyethylene (MDPE), low-density polyethylene (LDPE), Examples thereof include linear low density polyethylene (L-LDPE) and very low density polyethylene (V-LDPE). 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. Examples of other polyolefin resins include ethylene-4-methylpentene-1 resin, ethylene-vinyl acetate copolymer (EVA) and its saponified product, ethylene-vinyl alcohol resin (EVOH), ethylene-propylene copolymer ( EPM) and the like, polypropylene homopolymers, polypropylene block copolymers, polypropylene random copolymers, and the like, and chlorinated products of these polyolefins can be used as well. Moreover, these polyolefin can be used individually or in multiple selection.

  The polymerization method for synthesizing these polyolefin resins may be a generally known method, such as high pressure radical polymerization, medium-low pressure polymerization, solution polymerization, slurry polymerization, etc., and the catalyst used is a peroxide catalyst, Ziegler-Natta. Examples thereof include catalysts and metallocene catalysts, and 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 the halogen-based 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 the halogen-based solvent. For example, cylindrical pellets obtained by a strand cut method, an underwater hot cut method (underwater cut) Examples thereof include egg-shaped pellets, amorphous powders, granular materials, granules and the like produced by the above method. 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, a polyolefin resin (a molded body such as a powder or a high-quality film) can be produced. By using this polyolefin resin, an arbitrary molded body such as a film can be produced by a known molding method described later. This method will provide technology that can greatly contribute to the saving of fossil resources.

  The halogen-based solvent used in the production method of the present invention is not limited as long as the polyolefin resin is dissolved. For example, 1,1-dichloroethane, 1,2-dichloroethane, methylene chloride, chloroform, 1,1,1- Chlorinated solvents such as trichloroethane, 1,1,2-trichloroethane, carbon tetrachloride, trichlorethylene, perchloroethylene, brominated solvents such as ethane bromide, monofluorobenzene, 1,4-difluorobenzene, perfluoroheptane, perfluoroethylene Examples include fluorine-based solvents such as fluorooctane and dichloropentafluoropropane, and bromine and fluorine-containing solvents such as bromochloromethane and 1,2-dibromo-1,1-difluoroethane. These halogen solvents can be used in combination of two or more.

  Among these halogen-based solvents, halogen-based solvents that can dissolve the polyolefin resin at, for example, 80 to 110 ° C. are suitable, and halogen-based solvents having a low boiling point are suitable from the viewpoint of solvent evaporation. From such a viewpoint, 1,1,2-trichloroethane is preferable.

  The melting temperature of the polyolefin resin in the production method of the present invention is appropriately determined depending on the halogen-based solvent and the polyolefin used, and the melting temperature is 60 to 200 ° C. It is preferable from the economical aspect to dissolve at a normal pressure or less than the boiling point of the solvent. If the polyolefin resin does not dissolve, it can be dissolved at a temperature equal to or higher than the boiling point of the solvent using a pressure vessel if necessary. The dissolution time depends on the shape of the polyolefin resin and the dissolution temperature, but is 20 minutes to 8 hours. 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 the halogen-based solvent is preferably filtered with the polyolefin 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, a polymer such as polypropylene, a fluororesin, or the like. Nonwoven fabrics using 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 increase the filtration accuracy sequentially.

  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. In order to introduce into a 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 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.

  There is no restriction | limiting in particular in the density | concentration of a polyolefin solution, Although it is necessary to set suitably with the selected solvent, the density | concentration of 0.1 to 50 weight% is used.

  In dissolving the above polyolefin resin, various additives can be added in 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.

2) Solvent transpiration step As a method for evaporating the halogen-based solvent in the production method of the present invention, for example, a spray dry method in which a polyolefin solution is formed into droplets by spraying under reduced pressure can be used. In the method for forming a droplet of a polyolefin solution, the halogen-based solvent is evaporated from the polyolefin solution that has been formed into a droplet by discharging the polyolefin solution from a small-diameter nozzle into a vacuum container heated as necessary. In this case, the degree of vacuum is appropriately selected according to the selected halogen-based solvent and the temperature of the vacuum container. As long as the polyolefin solution is dropletized and the halogen-based solvent is evaporated from the droplet, the degree of vacuum and temperature are not affected. However, 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 can be molded 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.

  In addition, as another method for evaporating the halogen-based solvent in the production method of the present invention, for example, a method in which a polyolefin solution is continuously cast on a substrate to form a thin film and then dried by heating can be used. . As the base material, various polymer films typified by polyester films such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), and the surface of these polyester films are subjected to surface treatment by 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 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, in order to suppress the increase in the viscosity of the polyolefin solution due to rapid volatilization of the halogen-based solvent in the casting process, a die coater, It is preferred to use a double Mayer bar coater. 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.

  Drying of the polyolefin solution layer formed on the substrate can be performed in one step to multiple steps, and the temperature range is 50 to 200 ° C., and 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 into a film. it can.

  Other methods for producing the polyolefin resin of the present invention include, for example, a step of dissolving a polyolefin resin in a halogen-based solvent to prepare a polyolefin solution, and subsequently a step of cooling the solution to precipitate a polyolefin resin. A method comprising a step of evaporating a halogen-based solvent is mentioned.

  The dissolution process is the same as described above, and the other processes 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 is precipitated, but the shape of the solid may be substantially massive or granular.

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.

The film made of polyolefin resin obtained by the production method of the present invention is a high-quality film because the number of fish eyes of 50 μm or more is 10 or less / m ² in an unstretched film. It can be used as a film used in a protective film for dry film photoresists. If the number of fish eyes of 50 μm or more exceeds 10 / m ² in an unstretched film, it cannot be used as a masking film for which high quality is required. The number of fish eyes of 50 μm or more is preferably 5 or less / m ² , more preferably 3 or less / m ² , and most preferably 1 or less / m ² . Moreover, although high flatness is calculated | required by the film for a dry film resist use, 10-50 micrometers is preferable in this case, and 2 micrometers or less are preferable as thickness accuracy.

  INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a polyolefin resin suitable for the production of a high-quality film having a very wide industrial application range and reduced fish eyes, and a method for producing the same. Further, the polyolefin resin of the present invention is useful for a polyolefin film used for a protective film for a dry film photoresist 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>
(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 ), manufactured by 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 <Fisheye Measurement>
Since fish eyes 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 eyes in a 5 m long film are visually measured. ^It was calculated as the number per ^two .

<Measurement of gel and foreign matter>
The number of gels and foreign matters per 20 g of polyolefin resin was calculated from the number per 1 m ^{2 of} unstretched film of fish eyes of 50 μm or more.

<Measurement of film thickness>
Anritsu Corporation film thickness measuring instrument K-402B was used.

<Casting>
This was carried out 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 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. . The roll holding the film adjacent to the coating die was heated from behind using a halogen heater (model IRE182-N) manufactured by Iwasaki Electric Co., Ltd., and the temperature was adjusted by the voltage applied to the halogen heater.

<Deposition machine>
Connected to Toyo Seiki Seisakusho Co., Ltd. 100C100 type lab plast mill with D25-20 type full flight screw manufactured by Toyo Seiki Seisakusho Co., Ltd. Was deposited.

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 tank was pressurized, and the solution was cast on a PEN film as a base material from a die 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 under heating at 110 ° C. for 1 hour with stirring. 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. Moreover, from this result, L-LDPE had a gel of 50 μm or more and a foreign substance of 1 or less / 20 g.

Examples 3-10
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. Also, from these results, the polyolefin resin had a gel of 50 μm or more and 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 under heating at 110 ° C. for 1 hour with stirring. 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. Moreover, 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 obtained 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 matter 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 50 μm or more fish eyes were excellent at 0.5 / m ² . Moreover, from this result, EVA had a gel of 50 μm or more and a foreign substance of 1 or less / 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 had a gel of 50 μm or more and a foreign matter of 1 piece / 20 g.

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 with stirring at 110 ° C. for 1 hour 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 to measure the fish eye of the unstretched film. 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. Moreover, 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 many 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 70-100 micrometers were contained, and it was inferior to quality. Moreover, from these results, the polyolefin resin contained a large number of gels and foreign matters of 70 to 100 μm.

Claims (2)

The substrate process, and subsequently, Ri name includes the step of evaporating the halogenated solvent from the solution, the step of evaporating a halogen-based solvent, a polyolefin solution by dissolving a polyolefin resin with a halogen-based solvent to prepare a polyolefin solution after continuously flow cast thinned above method for producing a polyolefin resin 50μm or more gel and foreign matter, characterized that you drying is 10 or less / 20 g by heating. The method for producing a polyolefin resin according to claim 1 , wherein the halogen-based solvent is 1,1,2-trichloroethane.