JP2008024835A - Method for producing polypropylene resin film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a polypropylene resin film having excellent heat-resistant dimensional stability, little fisheye defects and proper transparency and suitable as a base film of a protection film. <P>SOLUTION: A polypropylene resin film is produced by melting a composition obtained by compounding 100 pts.mass of a resin composition composed of 85-96 pts.mass of a polypropylene block copolymer resin having an ethylene content of at least 5.5-9.9 mass% and 4-15 pts.mass of at least one kind of polypropylene resin selected from a polypropylene random copolymer resin having an ethylene content of ≤5 mass% and a polypropylene resin, with 0.01-0.1 pt.mass of a crystal nucleation agent, 0.01-0.1 pt.mass of an acrylate antioxidation agent and 0.05-1.0 pt.mass of at least one component selected from phosphorus-based antioxidation agents and phenolic antioxidation agents, extruding the molten resin from a die in the form of a thin film and cooling and solidifying the molten film with a chill roll. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing a polypropylene-based resin film, and in particular, has high heat deformation resistance at high temperatures, for example, has excellent processability such as adhesive processing, and has low transferability of additives. The present invention relates to a method for producing a polypropylene-based resin film that has less eye and is suitable for various uses, particularly for protecting the surface of various articles.

  Polypropylene-based unstretched films have good transparency and are inexpensive, and are therefore widely used as base materials for surface protection films for the purpose of protecting the surface of various packaging materials such as food packaging and various articles.

For example, even in the surface protection film field, a surface protection film is attached to the surface of a metal plate, decorative plate, resin plate, glass plate, etc. to prevent surface scratches, dirt and rust that tend to occur during transportation and processing. Method (for example, refer to Patent Documents 1 to 3), for example, scratches, dust adhesion, contamination during processing and assembly of electronic, precision products, components and related members such as related materials such as liquid crystal panels and polarizing plates As a coating surface protection film for protecting a coating film on an automobile body from acid rain, dust, dust, etc. during transportation and storage of the vehicle, for example, (For example, see Patent Documents 6 and 7, etc.) For example, as a method of partially plating the connection terminal portion of the flexible printed circuit board, an adhesive film is attached to the non-plated portion and the mask is used. Then, use in plating and etching processes such as a method of plating and a method of protecting a resist film or etching resistance film provided on an unetched surface in an etching process at the time of manufacturing a shadow mask (see, for example, Patent Documents 8 and 9) ), A method for protecting a surface of a semiconductor element by laminating a film on a surface without a circuit of the semiconductor element, and simplifying a process when assembling a semiconductor device (for example, see Patent Documents 10 and 11, etc.) Used in the field.
JP 2003-119435 A JP 2003-213229 A JP 2005-281328 A Japanese Patent Laid-Open No. 10-309781 JP 11-165368 A JP-A-8-143829 Japanese Patent Laid-Open No. 2001-121661 JP-A-11-291411 Japanese Patent Laid-Open No. 11-302611 JP 2004-63551 A JP 2004-142430 A JP-A-11-291411 Japanese Patent Laid-Open No. 11-302611

  The surface protective film is generally used by laminating an adhesive layer on the surface of a base film and fixing it to the surface of an object to be protected using the adhesive force of the adhesive layer. In recent years, with the expansion of applications, demands for quality and cost reduction have become stronger, and there is a demand for a base film having excellent adhesive processability. In particular, the processing temperature is increasing for the purpose of increasing the processing speed of adhesive processing, etc., and even when processed at a high temperature, thermal deformation due to the processing temperature is small, and dimensional stability during processing is good, There is a demand for dimensional stability at high temperatures (hereinafter, also simply referred to as heat-resistant dimensional stability) that suppresses the occurrence of hot flame during processing.

Regarding the surface protective film, there is no disclosure of the above-mentioned technology for improving the heat-resistant dimensional stability, but a composition in which an aromatic organophosphate metal salt is blended with a specific polypropylene resin has a cooling roll temperature of 40. A polypropylene resin film that is excellent in workability and dimensional stability in secondary processing such as high-speed film formation and metal deposition by extrusion molding at -50 ° C. and suitable for fiber packaging and food applications has been disclosed. (See Patent Document 14).
JP-A-10-298367

  In addition, the polypropylene resin film contains minute foreign matter called fish eye. For example, the definition of fish eye is written in Polymer Editorial Board, Polymer Dictionary, Taiseisha, 2000, 6th edition, P337, etc. A fish eye refers to a small spherical shape or the like formed in a film product. The name was given because there are many things that have transparency like fish eyes. There are various types such as unmelted lumps resulting from insufficient kneading of the molding material, lumps due to gelation of a part of the raw material, lumps due to partial deterioration of the material during molding, and those with foreign matter as the core. The fish eye here excludes those with foreign matter as the core. Examples of the foreign matter include cellulose, dust, metal pieces, resin carbide, plastics of different types, lint, and pieces of paper. For example, when packaging with a film containing a large amount of fish eyes, the fish eyes can be seen with the naked eye, which reduces the product image of the package, which is not preferable. With regard to the fish eye, in recent years, market demands have become stricter along with the increasing safety orientation of consumers. For example, even if it is not visible to the consumer under normal conditions, such as when used as an inner layer material for a paper pack, the paper pack will be cut out for collection to the consumer's eyes. As a result, phenomena such as raising anxiety about safety have begun to appear. In addition, when used as a transparent packaging bag, fish eyes may stand out as foreign matter depending on the color and form of the contents. These market requirements require strict management. Moreover, also in the above-mentioned protective film use, since the said external appearance defect reduces the product image of the goods protected, there exists a strong request of mixing suppression. In particular, for example, in the case of a protective film for plating, if the fish eye is present, a protrusion is formed in a portion where the fish eye is present on the film, and adhesion failure occurs between the protrusion and an object to be protected. A space is created between the object and the object, and the plating solution enters the space and the protective effect is reduced. Therefore, it is necessary to reduce it as much as possible. In the case of a protective film for protecting the LCD panel, the fish eye on the surface of the protective film may be damaged by the unevenness or rubbing of the fish eye when pressed on the surface in contact with the LCD panel. That is a problem. Recently, liquid crystal plates have been inspected with a protective film for protecting the liquid crystal plate. If fish eyes are present, it may be determined that the liquid crystal plate itself is a defect. The development of films such as grades and low fish eye grades is required.

  With respect to the surface protective film, there is no disclosure of a technique for suppressing the above fish eye, but a technique for suppressing the fish eye contamination of the polypropylene resin film is disclosed.

For example, a method for reducing the fisheye content in the raw resin is disclosed (for example,
(See Patent Documents 15 to 17). Although this method is effective as a method for reducing fish eyes, since fish eyes are also produced by a melt extrusion process or the like, it may be difficult to meet market demands only with this method.
JP-A-6-93061 JP 7-233291 A JP 2003-62954 A

In addition, the present inventors have disclosed a technique for reducing fish eyes by melt extrusion at a low temperature (see Patent Documents 18 and 19). Although the method of the present invention is an effective method for reducing fish eyes, there is a problem that it is necessary to use a limited film-forming machine in order to suppress the deterioration of thickness unevenness of the film obtained by low-temperature extrusion. Have.
JP 2005-178250 A JP-A-2005-179552

Moreover, the polypropylene resin composition which can reduce a fish eye is disclosed by using a phenolic antioxidant and sulfur type antioxidant as antioxidant (refer patent document 20). The method of the present invention is also an effective method for reducing fish eyes, but as shown in the examples, it is intended for fish eyes having a size of 0.2 mm or more, and the number of fish is 15 to 20 / m ² . Fisheye is included and further improvements are needed to meet the high demands of the market in recent years. For example, in the protective film for plating disclosed in Patent Document 8 and the like, the number of fish eyes of 0.2 mm or more is required to be substantially 0 as the number per area, and Small fisheye reduction is required.
JP 2003-268172 A

Further, a technique combining the technique approximated to Patent Document 14 and the technique approximated to Patent Document 20, that is, a polypropylene resin composition containing a crystal nucleating agent and two kinds of antioxidants, and molding formed by molding the same A body is disclosed (see Patent Documents 21 and 22).
JP 2000-109519 A JP 2000-248147 A

  In the technique disclosed in Patent Document 21, improvement of the heat distortion temperature is shown. Further, in the technique disclosed in Patent Document 22, an effect of improving impact resistance at a low temperature is shown. However, there is no mention of the effect that is the object of the present invention. For example, although the fish eye is not mentioned at all, the composition of the antioxidant that greatly affects the suppression of the fish eye is similar to the technique of Patent Document 20, and the fish described above is similar to the technique of Patent Document 20. It is presumed that it does not meet the high market demand for eye.

In recent years, attention has been focused on the fact that an acrylate-based antioxidant exhibits a good antioxidant effect when added in a small amount (see, for example, 23 to 26).
JP 58-84835 A Japanese Patent Laid-Open No. 1-168643 Japanese Patent Laid-Open No. 2001-114953 JP 2002-302579 A

  In the above-mentioned Patent Document 25, although it relates to a biaxially stretched polypropylene resin film using a homopolypropylene resin, two types of antioxidants, an acrylate antioxidant and a phenol antioxidant, or an acrylate antioxidant, Although the Example using together 3 types of antioxidants, a phenolic antioxidant and phosphorus antioxidant, is disclosed, the special effect is not shown compared with use of an acrylate antioxidant alone.

  The present invention is excellent in heat-resistant dimensional stability, has little fish eye, has moderate transparency, and has good handling properties of the film despite being substantially free of lubricants and anti-blocking agents. It is providing the manufacturing method of the polypropylene resin film suitable as a base film of a protective film.

  As a result of intensive studies to solve the above problems, the present inventors have completed the present invention.

また、この場合において、上記の冷却ロールの表面温度が６０〜９０℃であることが好ましい。
また、この場合において、上記の溶融押し出しを、少なくとも供給ゾーン、混練ゾーンおよび計量ゾーンよりなる押し出し機を用いて、かつ上記混練ゾーンの温度を供給ゾーンや計量ゾーンの温度より高温に設定することが好ましい。
また、この場合において、上記のアクリレート系酸化防止剤が下記（ＩＩ）式で示される構造よりなることが好ましい。

That is, the present invention provides a polypropylene block copolymer resin having an ethylene content of at least 5.5 to 9.9 mass% and a polypropylene random copolymer resin having an ethylene content of 5 mass% or less or The crystal nucleating agent is 0.01 to 0.1 parts by mass, and the acrylate antioxidant 0 to 100 parts by mass of the resin composition consisting of 4 to 15 parts by mass of at least one polypropylene resin selected from polypropylene resins. .01-0.1 part by mass, a composition containing 0.05-1.0 part by mass of at least one selected from phosphorus-based antioxidants and phenol-based antioxidants is melted from a die to form a thin film It is a method for producing a polypropylene resin film, which is extruded into a shape and cooled and solidified with a cooling roll.
In this case, the crystal nucleating agent is preferably composed of a cyclic organophosphate compound represented by the following general formula (I).

Moreover, in this case, it is preferable that the surface temperature of said cooling roll is 60-90 degreeC.
In this case, the melt extrusion may be performed using an extruder composed of at least a supply zone, a kneading zone, and a metering zone, and the temperature of the kneading zone may be set higher than the temperatures of the supply zone and the metering zone. preferable.
In this case, it is preferable that the acrylate antioxidant has a structure represented by the following formula (II).

  Since the polypropylene resin film obtained by the method for producing a polypropylene resin film of the present invention is excellent in heat-resistant dimensional stability, for example, it is excellent in secondary processing such as adhesive processing, particularly at a high temperature around 130 ° C. Since the generation of hot sag and film sagging is suppressed even when a treatment such as drying is performed, it is possible to improve the productivity of the secondary processing and to suppress the generation of defective products due to hot sag and film sagging. In addition, since the polypropylene resin film obtained by the method for producing a polypropylene resin film of the present invention does not substantially contain a lubricant, for example, when used as a base film for a packaging bag or a protective film, Since there is no transfer of the lubricant to the package or the object to be protected, contamination of these objects to be packaged or the object to be protected is suppressed. In addition, since the polypropylene resin film obtained by the method for producing a polypropylene resin film of the present invention does not substantially contain an antiblocking agent, for example, when a film containing an antiblocking agent is run, it wears out. The problem that the anti-blocking agent is detached due to the above can be avoided, so that contamination or failure due to the removed substance is suppressed. In addition, despite having substantially no lubricant or anti-blocking agent, the surface roughness is appropriate, the slipperiness of the film is good, and the rigidity is excellent, so the handleability of the film is excellent . Moreover, since it has moderate transparency, it is excellent in the visibility of a to-be packaged object or a to-be-protected body. In addition, since the fish eye is highly mixed, the appearance failure due to the fish eye, for example, when used as a base film of a protective film, penetration of the plating solution due to the above-mentioned adhesion failure to the protective part It is possible to suppress the occurrence of such troubles. In addition, despite the improved heat-resistant dimensional stability described above, it has excellent impact strength, and the impact resistance added by being made of block polypropylene resin is maintained. High reliability when used as a film. Therefore, it can be suitably used as a packaging for articles such as foods and precision parts, which are apt to be contaminated by films, and as a protective film for various precision parts.

  In the present invention, at least 85 to 96 parts by mass of a polypropylene block copolymer resin having an ethylene content of 5.5 to 9.9% by mass and a polypropylene random copolymer resin or polypropylene having an ethylene content of 5% by mass or less. 0.01 to 0.1 parts by mass of a crystal nucleating agent and 0.1 to 0.1 parts by mass of an acrylate antioxidant with respect to 100 parts by mass of a resin composition consisting of 4 to 15 parts by mass of at least one polypropylene resin selected from resins. 01-0.1 part by mass, a composition containing 0.05-1.0 part by mass of at least one selected from phosphorous antioxidants and phenolic antioxidants is melted from a die to form a thin film It is preferable to extrude, cool and solidify with a cooling roll.

  The polypropylene block copolymer resin used in the present invention is a block copolymer of a copolymer component of a large amount of propylene and a small amount of ethylene and a copolymer component of a small amount of propylene and a large amount of ethylene. The molecular weight of each copolymer block is controlled at the polymerization stage. Generally, as shown in JP-A-59-115312, it can be obtained by a polymerization method having two or more stages, but is not particularly limited in the present invention. It is important that the ethylene content contains 5.5 to 9.9% by weight. The ethylene content is preferably 6.0 to 9.5% by mass. When the ethylene content is less than 5.5% by mass, the surface roughness of the resulting film is lowered, the slipperiness and blocking resistance of the film are deteriorated, and the handleability of the film is lowered. Moreover, since the impact resistance of the obtained film deteriorates, it is not preferable. On the contrary, when the ethylene content exceeds 9.9% by mass, the haze value of the film is increased, the transparency is deteriorated, and the visibility of an object to be packaged or an object to be protected is lowered, which is not preferable. In addition, it is not preferable because fish eyes are easily generated and the variation in thickness becomes large.

The polypropylene block copolymer resin is not limited as long as the above requirements are satisfied, but it is preferable to use a resin having the following characteristics.
The 20 ° C. xylene soluble part is 3 to 50%, the intrinsic viscosity of the entire resin is 1.5 to 4.0, the intrinsic viscosity of the 20 ° C. xylene soluble part is 1.0 to 4.0, and the 20 ° C. xylene insoluble part. Those having an intrinsic viscosity of 1.0 to 4.0 are preferred. Moreover, what has a melt flow rate of 2-20 g / 10min in 230 degreeC is preferable.

  The polypropylene resin film of the present invention may contain 3 to 15% by mass of at least one polypropylene resin selected from a polypropylene random copolymer resin or a polypropylene resin having an ethylene content of 5% by mass or less. preferable. That is, a polypropylene random copolymer resin or polypropylene resin having an ethylene content of 5% by mass or less is formed by using a composition in which 3 to 14% by mass of a single or a mixture of both is mixed with respect to the total amount of the raw material composition. Is preferred. As for the compounding quantity of this resin, 6-13 mass% is more preferable. If it is less than 3% by mass, the effects described later are not exhibited, which is not preferable. On the contrary, if it exceeds 15% by mass, the slipperiness of the film is lowered, which is not preferable. The resin to be blended is preferably a random copolymer or homopolypropylene resin having an ethylene content of 1.0% by mass or less. In the present invention, the resin may be blended alone or as a matrix resin for a master batch of an antioxidant or a crystal nucleating agent described later. The compounded resin preferably has a melt flow rate of 3 to 10 g / 10 min at 230 ° C.

  Due to the above-mentioned measures, the motor load of the extruder can be reduced and the extrudability can be improved in the melt extrusion process. The reduction of the motor load can also be realized by increasing the resin temperature at the time of extrusion, but in this method, the deterioration of the resin increases, for example, the occurrence of an undesirable phenomenon such as an increase in fish eye generation. This is not preferable. In addition, for example, in the secondary processing step such as adhesion processing, the obtained film may be subjected to a method of slightly stretching the processed film in the transverse direction to the traveling direction in order to reduce heating wrinkles, a so-called extending method may be taken. However, due to the above measures, the spreadability is improved, and this also leads to the advantage that the effect of suppressing the occurrence of hot sores is easily expressed.

  As described above, in the present invention, it is preferable to blend a crystal nucleating agent. By adding the crystal nucleating agent, the heat resistant dimensional stability of the film can be improved. As specific film characteristics, elongation stress at 130 ° C. is improved, and the above-described effects can be exhibited. On the other hand, in order to increase the heat-resistant dimensional stability without adding a nucleating agent, it is necessary to increase the crystallinity of the film by adding a high crystal homo, or by stretching it weakly. If the amount is too large, the problem that the roughness of the surface decreases occurs. In addition, when performing weak stretching or the like, it is necessary to adjust the film forming apparatus, and it is difficult to change the draw or the like unless it is a dedicated machine. In that sense, a nucleating agent that can easily improve heat resistance is effective.

The crystal nucleating agent used in the present invention is not limited as long as it is a compound that exhibits a crystal nucleating agent effect on a polypropylene resin, a crystal nucleating agent containing a rosin metal salt as a main component, a sorbitol-based crystal nucleating agent, and an aromatic. A nucleating agent composed of an aromatic organic phosphoric acid ester metal salt, and a cyclic organic phosphoric acid ester represented by the following general formula (I) which is a kind of a nucleating agent composed of an aromatic organic phosphoric acid ester metal salt The use of a crystal nucleating agent comprising a compound is preferred.

In the cyclic organophosphate compound represented by the above general formula (I), examples of the alkyl group having 1 to 4 carbon atoms represented by R ¹ include methyl, ethyl, propylisopropyl, ptyl, nippibiso Examples include butyl. Examples of the alkyl group having 1 to 12 carbon atoms represented by R ² and R ³ include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, amyl, tert-amyl, hexyl, heptyl, Octyl, isooctyl, secondary octyl, 2-ethylhexyl, nonyl, isononyl, decyl, isodecyl, undecyl, dodecyl, tertiary dodecyl, etc .: as cycloalkyl groups, cyclobutyl, cyclohexyl, cyclopentyl, cycloheptyl, etc., as aralkyl groups, Examples include benzyl, α, α-dimethylbenzyl, α-methylbenzyl and the like. Further, examples of the metal atom of Group 3 or Group 4 of the periodic table represented by M include aluminum, gallium, germanium, tin, titanium, zirconium, and the like, and a compound in which M is aluminum is particularly preferable.

  In the case of the crystal nucleating agent comprising the above cyclic organophosphate compound, at least one selected from alkali metal compounds such as alkali metal carboxylate, alkali metal β-diketonate or alkali metal β-ketoacetate is used in a maximum of 40. You may contain to mass%. Alkali metal aliphatic monocarboxylates, particularly lithium aliphatic carboxylates are preferred, with aliphatic monocarboxylates having 8 to 20 carbon atoms being particularly preferred.

  Examples of the complexed crystal nucleating agent include ADK STAB NA-21 (Asahi Denka Kogyo Co., Ltd.).

  In this invention, it is preferable to add 0.01-0.1 mass part with respect to 100 mass parts of all the above-mentioned polypropylene resin compositions as a cyclic organophosphate ester compound. 0.02-0.09 mass part is more preferable, and 0.03-0.08 mass part is further more preferable. If it is less than 0.01 part by mass, the effect of improving the heat-resistant dimensional stability is insufficient, which is not preferable. On the other hand, when the amount exceeds 0.1 parts by mass, the effect of improving the heat-resistant dimensional stability is saturated, and it is rather undesirable that the transparency is lowered.

  In the present invention, with respect to 100 parts by mass of the total resin composition, 0.01 to 0.1 parts by mass of an acrylate antioxidant as an antioxidant, among phosphorus antioxidants and phenolic antioxidants. It is preferable to use the composition which mix | blended 0.05-1.0 mass part at least 1 sort (s) chosen from.

  In the present invention, as described above, it comprises at least two antioxidants selected from at least one selected from the group consisting of acrylate antioxidants, phosphorus antioxidants and phenolic antioxidants. However, it is a more preferable embodiment that three types of acrylate antioxidant, phosphorus antioxidant and phenolic antioxidant are used in combination.

  One of each of the three antioxidants may be used, or two or more of each type may be used in combination. Further, in addition to the above three kinds of antioxidants, for example, an antioxidant having another structure such as a sulfur-based antioxidant may be further used in combination.

  By using a plurality of the above-mentioned antioxidants in combination, a high level of fisheye mixing suppression effect that cannot be obtained by a combination of conventionally known antioxidants is exhibited. The reason is not clear, but is presumed as follows.

  Phenol-based antioxidants and phosphorus-based antioxidants have little selectivity for the antioxidant effect with respect to each component of the raw material resin composition described above, but acrylate-based antioxidants are used with the rubber part of the polypropylene-based block copolymer. It is known that the affinity is strong and the tendency to preferentially suppress the deterioration of the rubber part. On the other hand, regarding the generation of fish eyes, the contribution of the deterioration of the rubber part is large. Therefore, it is presumed that the combined use of the above-mentioned plurality of antioxidants led to a significant reduction in fish eyes.

The above acrylate antioxidant is an antioxidant having a phenol derivative containing an acrylate residue in the molecule, and preferably has a structure represented by the following formula (II).

In the formula (II), R ⁶ is an alkyl group having 1 to 5 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group, a t-butyl group, and a 2,2-dimethylpropyl group. A methyl group or an ethyl group is preferable, and an ethyl group is more preferable.

In the formula (II), R ⁷ is an alkyl group having 1 to 8 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group, a t-butyl group, a t-pentyl group, and a t-octyl group. It is done. A methyl group, a t-butyl group or a t-pentyl group is preferred, and a t-pentyl group is more preferred.

In the formula (II), R ⁸ is a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and examples thereof include a hydrogen atom, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and an octyl group. . Preferably they are a hydrogen atom or a methyl group, More preferably, it is a methyl group.

In the formula (II), R ⁹ is a hydrogen atom or a methyl group. Preferably it is a hydrogen atom.

  Examples of the acrylate compound include 2,4-di-t-amyl-6- [1- (3,5-di-t-amyl-2-hydroxyphenyl) ethyl] phenyl acrylate, 2,4-di- t-amyl-6- [1- (3,5-di-t-amyl-2-hydroxyphenyl) butyl] phenyl acrylate, 2,4-di-t-amyl-6- [1- (3,5- Di-t-amyl-2-hydroxyphenyl) propyl] phenyl acrylate, 2-t-butyl-6- (3-t-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate, and the like. .

  Preferably, 2,4-di-t-amyl-6- [1- (3,5-di-t-amyl-2-hydroxyphenyl) ethyl] phenyl acrylate and 2-t-butyl-6- (3- t-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate.

  As said acrylate compound, it can select from a commercially available thing suitably and can be used. For example, Sumitizer GM (registered trademark) manufactured by Sumitomo Chemical Co., Ltd., which is 2-t-butyl-6- (3-t-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate, 2,4 -Sumitizer GS (registered trademark) manufactured by Sumitomo Chemical Co., Ltd., which is di-t-amyl-6- [1- (3,5-di-t-amyl-2-hydroxyphenyl) ethyl] phenyl acrylate Can do. In particular, it is preferable to use a Sumilizer GS (registered trademark).

  Although the compounding quantity of the said acrylate antioxidant in this invention is not limited, The range of 0.01-0.1 mass part is preferable with respect to 100 mass parts of above described all polypropylene resin compositions. 0.02-0.08 mass part is more preferable, and 0.03-0.07 mass part is further more preferable. When the blending amount exceeds 0.1 parts by mass, the contamination of the cooling roll increases in the film forming step, which is not preferable. Also, the film is not preferable because it is dyed in the pale yellow color unique to antioxidants. On the other hand, if it is less than 0.01 parts by mass, the above-mentioned combined effect decreases, which is not preferable. It is preferable to lower the upper limit of the blending amount of the acrylate antioxidant alone than the above two kinds of antioxidants. The acrylate antioxidant is a polypropylene resin rubber compared to other antioxidants. Due to the high solubility in the component, it is more distributed to the rubber component in the film, and the rubber component portion has a slower crystallization rate by the cooling roll than the base resin, so that the rubber is in contact with the cooling roll. It is surmised that the above-mentioned acrylate antioxidant distributed to the components easily migrates to the cooling roll, and thus is caused by increasing the contamination degree of the cooling roll. For example, it is a peculiar phenomenon that occurs in the present invention that does not occur in the film formation using the homopolypropylene resin disclosed in the above-mentioned Patent Document 25 and the like.

  Specific examples of the phosphorus antioxidant include a heat stabilizer containing a trivalent phosphorus atom in the molecule, and the phosphorus atom has at least one P—O—C bond. For example, tributyl phosphite, trioctyl phosphite, trilauryl phosphite, tristearyl phosphite, tridecyl phosphite, tricresyl phosphite, tricyclohexyl phosphite, triphenyl phosphite, trilauryl thiophosphite, tris ( 2-ethylhexyl) phosphite, tris (isodecyl) phosphite, tris (tridecyl) phosphite, tris (2,4-di-t-butylphenyl) phosphite, tris (butoxyethyl) phosphite, tris (nonylphenyl) Phosphite, tris (3,5-di-t-butyl-4-hydroxyphenyl) phosphite, tris [4,4′-isopropylidenebis (2-t-butylphenol)] phosphite, tris (1,3- Gieste (Royloxyisopropyl) phosphite, 2-ethylhexyl diphenyl phosphite, decyl diphenyl phosphite, phenyl di-2-ethyl hexyl phosphite, phenyl didecyl phosphite, phenyl diisodecyl phosphite, phenyl di (tridecyl) phosphite, diphenyl nonyl phosphite, Diphenyl isooctyl phosphite, diphenyl isodecyl phosphite, diphenyl mono (tridecyl) phosphite, dibutyl hydrogen phosphite, 4,4′-isopropylidene diphenol alkyl (C12 to C15) phosphite, 4,4′-butylidenebis ( 3-methyl-6-tert-butylphenyl) di-tridecyl phosphite, 2,2-methylenebis (4,6-di-tert-butylphenyl) octyl Sufite, 2,2'-ethylidenebis (4,6-di-t-butylphenol) fluorophosphite, bis (2,4-di-t-butyl-6-methylphenyl) .ethyl phosphite, 4,4 ' -Isopropylidenebis (2-t-butylphenol) di (nonylphenyl) phosphite, distearyl pentaerythritol diphosphite, di (nonylphenyl) pentaerythritol diphosphite, diphenylpentaerythritol diphosphite, phenyl 4, 4'-isopropylidenediphenol pentaerythritol diphosphite, bis (4,6-di-t-butylphenyl) pentaerythritol diphosphite, bis (2,6-di-t-butyl-4-methylphenyl) Pentaerythritol diphosphite, phenyl -Bisphenol A pentaerythritol diphosphite, tetraphenyldipropylene glycol diphosphite, tetra (tridecyl) -1,1,3-tris (2-methyl-5-tert-butyl-4-hydroxyphenyl) butanediphos Phyto, tetra (C12-C15 mixed alkyl) -4,4′-isopropylidene diphenyl diphosphite, tetra (tridecyl) -4,4′-butylidenebis (3-methyl-6-tert-butylphenol) diphosphite, tetrakis (4 , 6-Di-t-butylphenyl) -4,4′-biphenylene diphosphonite, tetrakis (2-methyl-4,6-di-t-butylphenyl) -4,4′-biphenylene diphosphonite Bis (octylphenyl) -bis [4,4′-butylidenebis (3-methyl) 6-t-butylphenol)] • 1,6-hexanediol diphosphite, hydrogenated-4,4′-isopropylidene diphenol polyphosphite, 9,10-di-hydro-9-oxa-9-oxa- 10-phosphaphenanthrene-10-oxide, 2-[{2,4,8,10-tetrakis (1,1-dimethylethyl) dibenzo (D, F) (1,3,2) -dioxaphos Fephin-6-yl} oxy] -N, N-bis [2-[{2,4,8,10-tetrakis (1,1-dimethylethyl) dibenzo (D, F) (1,3,2) -Dioxaphosphine-6-yl} oxy] ethyl] ethanamine, 1,1,3-tris (2-methyl-4-di-tridecylphosphite-5-t-butylphenyl) butane, 3,4 , 5,6-Tetraben Like 1,2-oxa phosphane-2-oxide.

  Preferably, those having no pentaerythritol skeleton, tris (2,4-di-t-butylphenyl) phosphite, tris (3,5-di-t-butyl-4-hydroxyphenyl) phosphite, Bis (2,4-di-t-butyl-6-methylphenyl) .ethyl phosphite, tetrakis (2-methyl-4,6-di-t-butylphenyl) -4,4'-biphenylenediphosphonite It is.

  Commercially available products can also be used as the phosphorus-based antioxidant used in the present invention. For example, Irgafos 168 (manufactured by Ciba Specialty Chemicals), Irgafos 38 (manufactured by Ciba Specialty Chemicals), GSY- P101 (manufactured by Yoshitomi Fine Chemicals), Ultranox 641 (manufactured by GE Specialty Chemicals), and the like.

  Although the compounding quantity of the said phosphorus antioxidant in this invention is not limited, The range of 0.05-0.5 mass part is preferable with respect to 100 mass parts of above described all polypropylene resin compositions. 0.1-0.4 mass part is more preferable, and 0.15-0.3 mass part is further more preferable. If the blending amount is less than 0.05 parts by mass, the effect of using the above-mentioned antioxidant in combination decreases, which is not preferable. On the contrary, when the amount exceeds 0.5 parts by mass, the effect of using the above-described antioxidant in combination is saturated, film whitening due to the migration of the antioxidant to the film surface, contamination of the cooling roll in the film forming process, etc. Is not preferable.

  The phenolic antioxidant used in the present invention is an antioxidant having a phenol derivative in the molecule, such as 2,6-di-t-butyl-4-methylphenol, 2,6-di-t. -Butyl-4-ethylphenol, 2,6-dicyclohexyl-4-methylphenol, 2,6-di-t-amyl-4-methylphenol, 2,6-di-t-octyl-4-n-propylphenol 2,6-dicyclohexyl-4-n-octylphenol, 2-isopropyl-4-methyl-6-t-butylphenol, 2-t-butyl-2-ethyl-6-t-octylphenol, 2-isobutyl-4-ethyl -6-t-hexylphenol, 2-cyclohexyl-4-n-butyl-6-isopropylphenol, dl-α-tocopherol, t-butyl Droquinone, 2,2'-methylenebis (4-methyl-6-tert-butylphenol), 4,4'-butylidenebis (3-methyl-6-tert-butylphenol), 4,4'-thiobis (3-methyl-6) -T-butylphenol), 2,2-thiobis (4-methyl-6-t-butylphenol), 4,4'-methylenebis (2,6-di-t-butylphenol), 2,2'-methylenebis [6- (1-methylcyclohexyl) -p-cresol], 2,2′-ethylidenebis (4,6-di-t-butylphenol), 2,2′-butylidenebis (2-t-butyl-4-methylphenol), 2-t-butyl-6- (3-t-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate, 2- [1- (2-hydroxy-3,5 -Di-t-pentylphenyl) ethyl] -4,6-di-t-pentylphenyl acrylate, 1,1,3-tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane, triethylene Glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3,5-di-tert-butyl-4-hydroxy) Phenyl) propionate], 2,2-thiodiethylenebis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], N, N′-hexamethylenebis (3,5-di-t -Butyl-4-hydroxy-hydrocinnamide), 3,5-di-t-butyl-4-hydroxybenzylphosphonate-diethyl ester, tris (2,6-dimethyl) 3-hydroxy-4-t-butylbenzyl) isocyanurate, tris (3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate, tris [(3,5-di-t-butyl-4-hydroxy Phenyl) propionyloxyethyl] isocyanurate, tris (4-t-butyl-2,6-dimethyl-3-hydroxybenzyl) isocyanurate, 2,4-bis (n-octylthio) -6- (4-hydroxy-3) , 5-Di-t-butylanilino) -1,3,5-triazine, tetrakis [methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] methane, 2,2′-methylenebis (4-Methyl-6-tert-butylphenol) terephthalate, 1,3,5-trimethyl-2,4,6-tris (3,5-di- t-butyl-4-hydroxybenzyl) benzene, 3,9-bis [1,1-dimethyl-2- {β- (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy} ethyl]- 2,4,8,10-tetraoxaspiro [5,5] undecane, 2,2-bis [4- (2- (3,5-di-tert-butyl-4-hydroxyhydrocinnamoyloxy)) ethoxy Phenyl] propane, β- (3,5-di-t-butyl-4-hydroxyphenyl) propionic acid stearyl ester, and the like.

  Preferably, β- (3,5-di-t-butyl-4-hydroxyphenyl) propionic acid stearyl ester, tetrakis [methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] Methane, tris (3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4- Hydroxybenzyl) benzene, dl-α-tocopherol, tris (2,6-dimethyl-3-hydroxy-4-tert-butylbenzyl) isocyanurate, tris [(3,5-di-tert-butyl-4-hydroxyphenyl) ) Propionyloxyethyl] isocyanurate, 3,9-bis [1,1-dimethyl-2- {β- (3-tert-butyl-4-hydroxy-5-methyl) Butylphenyl) propionyloxy} ethyl] -2,4,8,10-tetra-oxa-spiro [5,5] undecane.

  Commercially available products may be used as the phenolic antioxidant (D) used in the present invention. For example, Irganox 1010 (manufactured by Ciba Specialty Chemicals), Irganox 1076 (Ciba Specialty Chemicals) Irganox 1330 (manufactured by Ciba Specialty Chemicals), Irganox 3114 (manufactured by Ciba Specialty Chemicals), Irganox 1425WL (manufactured by Ciba Specialty Chemicals), and the like.

  Although the compounding quantity of the said phenolic antioxidant in this invention is not limited, The range of 0.05-0.5 mass part is preferable with respect to 100 mass parts of above described all polypropylene resin compositions. 0.1-0.4 mass part is more preferable, and 0.15-0.3 mass part is further more preferable. If the blending amount is less than 0.05 parts by mass, the effect of using the above-mentioned antioxidant in combination decreases, which is not preferable. On the contrary, when the amount exceeds 0.5 parts by mass, the effect of using the above-described antioxidant in combination is saturated, film whitening due to the migration of the antioxidant to the film surface, contamination of the cooling roll in the film forming process, etc. Is not preferable.

  The method for preparing the polypropylene resin composition containing the antioxidant and the crystal nucleating agent used in the present invention is not particularly limited, and examples thereof include known methods. Examples thereof include a method of heat-melt kneading using a kneader such as a kneader, a Banbury mixer, or a roll, and a method of heat-melt kneading using a single screw or twin screw extruder. Various resin pellets may be dry blended. In the method for preparing the composition, the antioxidant and the crystal nucleating agent may be added directly to the respective powders, or may be added as a master batch previously mixed with the polypropylene resin. When adding as a masterbatch, it may be prepared for each additive or may be prepared by mixing two or more. Moreover, you may implement combining the commercially available resin in which the said additive was mix | blended well. In addition, the composition may be prepared in advance to be supplied to a film forming process and supplied to a film forming extruder, or the components constituting the composition may be supplied to the film forming extruder. It may be supplied and prepared to form a film.

  In the present invention, it is important that the polypropylene resin composition having the above composition is melted from a die, extruded into a thin film, and cooled and solidified with a cooling roll.

  In this invention, it is a preferable embodiment that the surface temperature of said cooling roll shall be 60-90 degreeC. For example, when the surface temperature of the cooling roll, which is a condition disclosed in Patent Document 14 or the like, is carried out at less than 60 ° C., the effect of improving the heat-resistant dimensional stability is lowered, which is not preferable. On the contrary, when it exceeds 90 ° C., a touch roll mark of the cooling roll is generated, which is not preferable. In addition, transparency may be reduced. In addition, the cooling temperature in the Example of patent document 14 is 50 degreeC.

  In the present invention, it is preferable that the melt extrusion is performed using an extruder including at least a supply zone, a kneading zone, and a metering zone, and the temperature of the kneading zone is set higher than the temperatures of the supply zone and the metering zone. . That is, by increasing the set temperature of the kneading zone above the set temperature of the supply zone and the measuring zone before and after the kneading zone, the melting rate of the polypropylene resin composition is increased without lowering the measurement accuracy of the molten resin to the die. The generation of fish eyes can be suppressed by increasing the melting rate. Although this temperature difference is not limited, 5-15 degreeC is preferable. For example, it is preferable to set the temperature of the supply zone and the metering zone to 220 to 235 ° C and the temperature of the kneading zone to 240 to 260 ° C. The reason why the generation of fish eye can be suppressed by this countermeasure is not clear, but it is presumed that the effect of suppressing the formation of fish eye by the composite antioxidant system described above increases by increasing the melting rate of the polypropylene resin composition. ing.

  In the present invention, thickness control and thickness spot control are important items. In order to control the thickness, it is important to maintain a pressure before the die of about 10 to 20 MPa. If the pressure before the die is maintained at 10 to 20 MPa, the thickness accuracy is easily obtained, and the thickness variation is reduced. This is presumed to be because the pressure balance in the T-die is kept even.

  In the present invention, resin filtration is important and leads to suppression of fish eyes. Use of a leaf desk filter or a sintered filter is preferred. A wire mesh filter with a special weaving method such as twill tatami weave is good. The finer the mesh of the filter, the better. However, polypropylene has a limit because of its high viscosity. The thing of the filtration precision of 40-80 micrometers is preferable. In addition, it is also a preferred embodiment that two filters are installed not only at one place but also at two places, for example. When performing filtration, it is important to confirm the pressure resistance. When the pressure difference ΔP before filtration and after filtration exceeds the filtration pressure resistance, not only the foreign matter that has been captured up to now will be discharged, but also the filter itself will be damaged and unusable. The filtration pressure resistance varies depending on the filter for filtration and the filtration accuracy, and is preferably optimized for use.

  In the method for producing a polypropylene resin film of the present invention, the extruded film can be subjected to a surface treatment such as a corona discharge treatment or a flame treatment by a method generally employed industrially.

  Although the thickness of the film obtained by the said manufacturing method is not specifically limited, It is common that it is 1-500 micrometers, and the thing of preferable thickness is selected as needed.

  Reference will be made to preferable properties that the polypropylene resin film obtainable by the above-described method for producing a polypropylene resin film of the present invention should have.

  In the polypropylene resin film of the present invention, it is important that the content of the lubricant in the film is 50 ppm or less. The content of the lubricant is more preferably 10 ppm or less, and particularly preferably the detection limit or less by a usual quantitative method such as elemental analysis or extraction method. That is, it is preferable that substantially no lubricant is contained. Here, “substantially containing no lubricant” means forming a film without positively adding the lubricant. The above range is to include that there is a case where a minute amount is mixed due to brand switching or the like at the time of manufacturing a raw material polymer or film without positively adding a lubricant, and it is a preferable embodiment that substantially does not contain a lubricant. is there. In the method of blending the lubricant and improving the slipperiness of the film due to the countermeasure, the migration of the lubricant to the film surface and the contamination of the packaged object or the protected object due to the subsequent transfer to the packaged object or the protected object occur. It is blocked and the clarity of the article to be packaged and the object to be protected is maintained.

  In the polypropylene resin film of the present invention, the content of the antiblocking agent in the film is preferably 50 ppm or less. The content of the anti-blocking agent is more preferably 10 ppm or less, and particularly preferably the detection limit or less by a usual quantitative method such as ash or elemental analysis. That is, it is preferable not to contain an antiblocking agent substantially. Here, substantially not containing an antiblocking agent has the same meaning as in the case of the above-mentioned lubricant. By this measure, the anti-blocking agent is prevented from falling off due to film abrasion in the film production and secondary processing steps, so that contamination, troubles, and the like due to the fall-off are suppressed.

  In the present invention, as described above, it is preferable not to add a lubricant or an anti-blocking agent that is used in a normal polypropylene resin film, so it is necessary to suppress deterioration of the slipperiness and blocking property of the film due to the correspondence. There is. The correspondence is preferably carried out by the above-described resin composition, in particular, film surface protrusions with a sea / island structure made of a block copolymer resin. On the other hand, the formation of film surface protrusions due to the sea / island structure with the block copolymer resin causes a decrease in transparency of the film. Therefore, in this method, the effect of improving slipperiness and blocking resistance due to the formation of surface protrusions and transparency Ensuring sex is a contradictory phenomenon. Therefore, the haze value of the film is an important factor. For example, the use of a block copolymer resin having a high ethylene content as disclosed in Patent Document 22 is effective in improving the above-described slipping property and blocking resistance. This is not preferable because the value is increased and the transparency is deteriorated, and the visibility of the article to be packaged or the object to be protected is lowered. Therefore, in the present invention, the haze value of the film is preferably 30% or less. 28% or less is preferable, and 25% or less is more preferable. When the haze value exceeds 30%, the transparency is deteriorated, and the visibility of the article to be packaged or the object to be protected is lowered. On the other hand, the lower limit of the haze value is preferably lower than the transparency point, but it is preferably 5% or more and more preferably 10% or more in relation to the point of imparting slipperiness by the above method.

  In the present invention, it is important that the polypropylene resin film of the present invention has a static friction coefficient of 0.95 or less after satisfying the above characteristics. 0.9 or less is more preferable, and 0.8 or less is more preferable. If the static friction coefficient exceeds 0.95, the film slips and the film is formed and wrinkles may occur at the time of winding. If it is 0.95 or less, wrinkles are difficult to enter during winding. The lower limit is preferably 0.4 or more and more preferably 0.5 or more in balance with other characteristics.

  If the static friction coefficient exceeds 0.95, the film slips and the film is formed and wrinkles may occur at the time of winding. If it is 0.95 or less, wrinkles are difficult to enter during winding.

  Moreover, it is preferable that the polypropylene resin film of the present invention has a blocking resistance of 350 N / 70 mm or less. 330 N / 70 mm or less is more preferable. When the blocking resistance exceeds 350 N / 70 mm, the film may be blocked due to long-term storage or the like, which is not preferable.

  The method for imparting the slipperiness and blocking resistance is not limited, but is greatly affected by the ethylene content described above. It is preferably achieved as the overall effect of the preferred embodiments described herein including the ethylene content.

  In the present invention, it is important that the polypropylene resin film of the present invention has a stress of 1.5 MPa or more at 5% elongation at 130 ° C. of the film. The pressure is preferably 1.6 MPa or more, and more preferably 1.7 MPa or more. The stress at 5% elongation at 130 ° C. is a measure of the heat-resistant dimensional stability of the film. Due to the correspondence, it is excellent in secondary processing such as adhesive processing, particularly at a high temperature around 130 ° C. Since the generation of hot soot is suppressed even when a treatment such as drying is performed, the productivity of the secondary processing can be improved. Moreover, generation | occurrence | production suppression of the inferior goods resulting from lack of heat resistance of films, such as hot water and a heat sagging, can be suppressed. The upper limit is preferably about 2.0 Mpa from the balance with other characteristics.

  The means for achieving the above heat-resistant dimensional stability is not limited, but the blending of the crystal nucleating agent described above is one of the important factors.

In the present invention, the polypropylene resin film of the present invention has 0 fisheye / m ² having a maximum diameter of 0.2 mm or more and 100 fisheye having a maximum diameter of 0.1 mm or less. It is important that it is not more than / m ² . The number of fish eyes having a maximum diameter of 0.1 mm or less is most preferably 0 / m ² or less, but the above range is preferable in view of economic efficiency and market demand. 2-80 pieces / m ² or less is more preferable, and 2-60 pieces / m ² or less is more preferable. By this correspondence, when it is used as a base film of a protective film, for example, when it is used as a base film of a protective film, it is possible to suppress the occurrence of troubles due to the penetration of the plating solution into the protective part due to the above-mentioned poor adhesion.

  The means for achieving the above properties is not limited, but optimization of the antioxidant composition described above is one of the important factors.

  In the present invention, the polypropylene resin film of the present invention preferably has a Young's modulus in the longitudinal direction at 23 ° C. of 650 Mpa or more. 680 Mpa or more is more preferable, and 720 Mpa or more is more preferable. 650 Mpa is not preferable because the handleability of the film is lowered. By this measure, it is possible to suppress a decrease in the handleability of the film due to the absence of the above-mentioned lubricant or antiblocking agent. The upper limit is preferably about 1000 Mpa from the balance with other characteristics.

  In the present invention, the polypropylene resin film of the present invention preferably has an impact strength at 23 ° C. of 0.6 J or more. 0.7J or more is more preferable. In general, when the rigidity and heat-resistant dimensional stability described above are improved, the impact strength moves in a decreasing direction. When the impact strength is reduced, the reliability of the impact resistance during use when used as a packaging bag, a protective film or the like is lowered. Therefore, it is preferable to satisfy the above-mentioned characteristics while giving the above-mentioned characteristics. The upper limit is preferably about 1.0 J from the balance with other characteristics.

  The above preferable characteristics can be stably produced by carrying out the above-described polypropylene resin film production method of the present invention.

"
Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited by the following examples, but may be implemented with appropriate modifications within a scope that can meet the gist of the present invention. These are all included in the technical scope of the present invention.

  The measurement and evaluation methods employed in this specification are as follows.

(1) Melt flow rate [MFR]
According to JIS K7210, it was measured by the method of Condition-14 (load 2.16 kg, temperature 230 ° C.).

(2) Ethylene content The ethylene content was measured by ¹³ C-NMR method according to the method described on page 616 of Polymer Handbook (published by Kinokuniya Shoten in 1995).

(3) Haze value Based on JIS-K-6714, it measured using "Haze Tester J" made by Toyo Seiki Seisakusho.

(4) Blocking resistance In accordance with ATM-D1893-67, a load of 90N was applied to the area of A4 size and left for 2 hours in an atmosphere at 60 ° C. The measurement was performed under the condition of 100 mm / min.

(5) Coefficient of static friction The slipperiness was measured according to JIS-K7215-1987 by combining the front and back surfaces of the film.

(6) Stress at 5% elongation at 130 ° C. (F5)
Set the distance between chucks of Autograph (manufactured by Shimadzu Corporation) to 100 mm. The pulling speed is adjusted to 200 mm / min. The temperature of the heating chamber is stabilized at 130 ° C. Five samples of 150 mm in the vertical direction and 20 mm in the horizontal direction are prepared. In order to prevent the sample from being broken, protect the film part sandwiched by the chuck with double-sided tape on both sides of the film. The sample is set between the chucks, the chamber lid is closed, and pulling is started after 15 seconds. The stress value at 5% elongation is read from the chart.

(7) Young's modulus In accordance with JIS K7127, the sample shape conforms to No. 1 type test piece (sample length 200 mm, sample width 15 mm, chuck distance 100 mm), and the crosshead speed is 500 mm / min. The MD direction (film longitudinal direction) was measured at 23 ° C.

(8) Impact strength In accordance with ASTM D3420, the sample is cut to 55 to 60 cm in the vertical direction and 9 to 10 cm in the horizontal direction. Read the strength value when punched using an impact tester in a 23 ° C room to the first decimal place. The operation is repeated 10 times, and the average value is obtained.

(9) Fisheye Cut the molded film 33.3 cm in the flow direction × 30 cm in the direction transverse to the flow direction, place it on the plate irradiated with a fluorescent lamp from under the film, and visually observe it with transmitted light. Measure fish eyes of 0.1 mm or more. Next, if the counted fish eye is immersed in liquid nitrogen and hardened, it is cut in half with a razor and the cross section of the fish eye is observed with a microscope at 50 to 300 times. For example, if there is no foreign matter such as cellulose, it is an unmelted lump, a lump due to gelation of a part of the raw material, or a gel-induced fish such as lump due to partial deterioration of the material during molding. Judged as eye. If there is a nucleus, it is judged as a fish eye caused by a foreign object and excluded from the count.

(10) Blocking resistance Blocking property is overlapped with the surface in contact with the cooling roll surface during film formation, tracing paper is overlapped on the overlapped surface and placed in a warm air dryer, and seasoning is performed at 50 ° C. for 30 minutes. Do. At that time, a sample is temporarily fixed with a clip or a staple to prevent the sample from shifting. The sample is put on a 50 ° C. heat press and subjected to pressure for 40 kg / cm ² × 15 minutes. The sample was cut into a width of 70 mm, and the film was separated into two sheets. An aluminum bar having a diameter of 6 mm and a width of 330 mm was used for peeling between the films, and the peeling resistance at a rate of 100 mm / min was read. The measurement is performed 4 times and the average value is obtained.
(11) Three-dimensional surface average roughness (SRa)
Using a three-dimensional surface roughness measuring instrument (model ET-30HK) manufactured by Kosaka Laboratory Ltd., measurement was performed under the following conditions, and the average surface roughness (SRa) was displayed.
Setting conditions Needle pressure [mg]: 20mg
Measurement length [mm]: 1.0
Measurement speed [mm / S]: 0.1
Measurement pitch (X pitch) [μm]: 2.0 μm
(Y pitch) [μm]: 2.0 μm
Measuring surface 1mm x 0.2mm
Z measurement magnification: 20000
Cut-off [mm] (low-frequency cut): 0.08
(High frequency cut): R + W
Leveling: Least square method Overall view (Y magnification) / (X magnification) = 5
(Z magnification) / (X magnification) = 50
(Viewing angle) = 30 °

(12) Extrudability The raw material resin composition is melt-extruded under the following extrusion conditions, and the motor current amount (A) value, which is a measure of the extruder motor load at the time of extrusion, is converted into an analog meter (JIS C1102 1.5). Class type ML-110, FS 100 mV). A case where the current value exceeded 680 A or better (◯) 680 A was judged as defective (×).
Extrusion conditions Screw diameter: 200mm
L / D: 29
Rotation speed: 50rpm
Discharge rate: 455kg / hr
Outlet temperature: 257 ° C

(Example 1)
0.22% by mass of Irgafos 168 (manufactured by Ciba Specialty Chemicals Co., Ltd.) as a phosphorous antioxidant and 0 of Irganox 1010 (manufactured by Ciba Specialty Chemicals Co., Ltd.) as a phenolic antioxidant 89 parts by mass of block copolymerized polypropylene resin (MFR = 2) having an ethylene content of 7.0% by mass containing 0.28% by mass, and a random copolymerized polypropylene resin (MFR = 7) having an ethylene content of 0.5% by mass ) 5 parts by mass and bis (2,2′-methylene-bis (4,6-di-tert-butylphenyl) phosphate) -aluminum hydroxide salt as a cyclic organophosphate compound (Asahi Denka Kogyo Co., Ltd.) Manufactured by ADK STAB NA-21) including a crystal nucleating agent comprising 1% by mass of a homopolypropylene resin (MFR = 7) An acrylate antioxidant comprising 5 parts by mass of a masterbatch resin (M-1) and 5% by mass of Sumylizer GS (manufactured by Sumitomo Chemical Co., Ltd.), which is an acrylate antioxidant, comprising a homopolypropylene resin (MFR = 7). 1 part by mass of a masterbatch resin (M-2) containing was melt-extruded with a T-die film forming machine to obtain an unstretched film having a thickness of 50 μm at a cooling roll temperature of 80 ° C. The resin temperatures of the feeding zone, the kneading zone, and the metering zone of the extruder were set to 230, 240, and 235 ° C, respectively. The results are shown in Table 1.
The polypropylene-based resin film obtained in this example was good in all properties shown in Table 1 and high in quality.

(Example 2)
In the method of Example 1, 0.28% by mass of Irgafos 168 (manufactured by Ciba Specialty Chemicals Co., Ltd.) using a block copolymerized polypropylene resin as a phosphorus-based antioxidant and Irganox 1010 (manufactured by Ciba Specialty Chemicals Co., Ltd.) Ciba Specialty Chemicals Co., Ltd.) containing 0.22% by mass of block copolymerized polypropylene resin having an ethylene content of 9.0% by mass and random copolymerized polypropylene resin having an ethylene content of 9.0% by mass. A polypropylene resin film of Example 2 was obtained in the same manner as in Example 1 except that the content of 2% by mass was changed to 7 parts by mass. The results are shown in Table 1.
The polypropylene resin film obtained in this example had the same properties as the polypropylene resin film obtained in Example 1 and was of high quality.

(Example 3)
In the method of Example 1, the block copolymerized polypropylene resin was replaced with 92 parts by mass of the block copolymerized polypropylene resin having an ethylene content of 4.8% by mass, and the random copolymerized polypropylene resin was replaced with the homopolypropylene resin. Except changing to a mass part, the polypropylene resin film of Example 2 was obtained by the same method as Example 1. The results are shown in Table 1.
The polypropylene resin film obtained in this example had the same properties as the polypropylene resin film obtained in Example 1 and was of high quality.

Example 4
In the method of Example 1, the compounding of Irgafos 168 (manufactured by Ciba Specialty Chemicals Co., Ltd.), which is a phosphorous antioxidant, to the block copolymerized polypropylene resin is canceled, and Irganox, which is a phenolic antioxidant, is used. A polypropylene resin film of Example 4 was obtained in the same manner as in Example 1 except that the blending amount of 1010 (manufactured by Ciba Specialty Chemicals Co., Ltd.) was changed to 4500 ppm. The results are shown in Table 1.
Compared with the polypropylene resin film obtained in Example 1, the polypropylene resin film obtained in this example was of high quality although the effect of suppressing fish eyes and the effect of improving slipperiness were slightly reduced.

(Example 5)
In the method of Example 1, the blending of Irganox 1010 (manufactured by Ciba Specialty Chemicals Co., Ltd.), which is a phenolic antioxidant, into the block copolymerized polypropylene resin is canceled and is a phosphorus antioxidant. A polypropylene resin film of Example 5 was obtained in the same manner as in Example 1 except that the amount of Irgafos 168 (manufactured by Ciba Specialty Chemicals Co., Ltd.) was changed to 4500 ppm. The results are shown in Table 1.
Compared with the polypropylene resin film obtained in Example 1, the polypropylene resin film obtained in this example was of high quality although the effect of suppressing fish eyes and the effect of improving slipperiness were slightly reduced.

(Comparative Example 1)
In the method of Example 1, a polypropylene resin film of Comparative Example 1 was obtained in the same manner as in Example 1 except that the block copolymerized polypropylene resin was changed to one having an ethylene content of 3.5% by mass. . The results are shown in Table 1.
The polypropylene resin film obtained in this comparative example was inferior in the slipperiness, blocking resistance and impact of the film and was of low quality.

(Comparative Example 2)
In the method of Example 1, a polypropylene resin film of Comparative Example 2 was obtained in the same manner as in Example 1 except that the block copolymerized polypropylene resin was changed to one having an ethylene content of 15% by mass. The results are shown in Table 1.
The polypropylene resin film obtained in this comparative example had a high film haze value, poor transparency, and low quality.

(Comparative Example 3)
Example 1 with the exception of stopping the supply of 5% by mass of the masterbatch resin (M-1) containing a crystal nucleating agent by the method of Example 1 and changing the supply amount of the random copolymer polypropylene resin to 10% by mass. A polypropylene resin film of Comparative Example 3 was obtained in the same manner. The results are shown in Table 1.
The polypropylene resin film obtained in this comparative example had a low F5 value and poor heat-resistant dimensional stability. In addition, the fish eye slightly increased compared with the polypropylene resin film obtained in Example 1, and the quality was low.

(Comparative Example 4)
In the method of Example 1, supply of the masterbatch resin (M-2) containing the acrylate antioxidant was stopped, and instead, Irganox 1010 (Ciba Specialty), which is a phenolic antioxidant to the block copolymerized polypropylene resin, was used. Chemicals Co., Ltd.) was increased to 0.28% by mass and the supply of the random copolymerized polypropylene resin was changed to 6% by mass. A film was obtained. The results are shown in Table 1.
The polypropylene resin film obtained in this comparative example had many fish eyes and low quality despite the total amount of the antioxidant being equal to that of the polypropylene resin film of Example 1.

(Comparative Example 5)
In the method of Example 1, except that the block copolymerized polypropylene resin in which the blending of the phosphorus antioxidant and the phenolic antioxidant is stopped is used and the blending amount of the acrylate antioxidant is increased to 1500 ppm. Obtained the polypropylene resin film of Comparative Example 7 in the same manner as in Example 1. The results are shown in Table 2.
The polypropylene resin film obtained in this comparative example had many fish eyes and low quality. Moreover, the contamination of the cooling roll increased.

(Comparative Example 6)
In the method of Example 1, the supply of the masterbatch resin (M-1) containing the crystal nucleating agent and the masterbatch resin (M-2) containing the acrylate antioxidant was stopped, and the supply of the random copolymer polypropylene resin was stopped. A polypropylene resin film of Comparative Example 8 was obtained in the same manner as in Example 1 except that the content was changed to 11% by mass. The results are shown in Table 2.
The polypropylene resin film obtained in this comparative example had a low F5 value at 130 ° C. and inferior heat-resistant dimensional stability, and also had many fish eyes and low quality.

(Comparative Example 7)
In the method of Comparative Example 6, except for stopping supply to the random copolymer polypropylene resin,
A polypropylene resin film of Comparative Example 7 was obtained in the same manner as Comparative Example 6. The results are shown in Table 2.
In addition to the problems of the polypropylene resin film obtained in Comparative Example 6, the polypropylene resin film obtained in this comparative example increased the motor addition of the extruder and lowered the extrudability.

(Comparative Example 8)
A polypropylene resin film of Comparative Example 10 was obtained in the same manner as in Comparative Example 4 except that the cooling roll temperature was changed to 50 ° C. in Comparative Example 4. The results are shown in Table 2.
In addition to the problem of the polypropylene resin film obtained in Comparative Example 4, the polypropylene resin film obtained in this Comparative Example was inferior in heat-resistant dimensional stability and was of lower quality.

(Comparative Example 9)
A polypropylene resin film of Comparative Example 9 was obtained in the same manner as in Comparative Example 3, except that the resin temperature in the kneading zone of the extruder was changed to 230 ° C. in Comparative Example 3. The results are shown in Table 2.
In addition to the problem of the polypropylene resin film obtained in Comparative Example 3, the polypropylene resin film obtained in this Comparative Example had an increased fish eye and was of lower quality.

  Since the polypropylene resin film obtained by the method for producing a polypropylene resin film of the present invention is excellent in heat-resistant dimensional stability, for example, it is excellent in secondary processing such as adhesive processing, particularly at a high temperature around 130 ° C. Since the generation of hot sag and film sagging is suppressed even when a treatment such as drying is performed, it is possible to improve the productivity of the secondary processing and to suppress the generation of defective products due to hot sag and film sagging. In addition, since the polypropylene resin film obtained by the method for producing a polypropylene resin film of the present invention does not substantially contain a lubricant, for example, when used as a base film for a packaging bag or a protective film, Since there is no transfer of the lubricant to the package or the object to be protected, contamination of these objects to be packaged or the object to be protected is suppressed. In addition, since the polypropylene resin film obtained by the method for producing a polypropylene resin film of the present invention does not substantially contain an antiblocking agent, for example, when a film containing an antiblocking agent is run, it wears out. The problem that the anti-blocking agent is detached due to the above can be avoided, so that contamination or failure due to the removed substance is suppressed. In addition, although it contains substantially no lubricant or antiblocking agent, the surface roughness is appropriate, the slipperiness of the film is good, and the rigidity is excellent. Yes. Moreover, since it has moderate transparency, it is excellent in the visibility of a to-be packaged object or a to-be-protected body. In addition, since the fish eye is highly mixed, the appearance failure due to the fish eye, for example, when used as a base film of a protective film, penetration of the plating solution due to the above-mentioned adhesion failure to the protective part It is possible to suppress the occurrence of such troubles. In addition, despite the improved heat-resistant dimensional stability described above, it has excellent impact strength, and the impact resistance added by being made of block polypropylene resin is maintained. High reliability when used as a film. Therefore, it can be suitably used as a packaging for articles such as foods and precision parts, which are apt to be contaminated by films, and as a protective film for various precision parts. Therefore, it is important to contribute to the industry.

Claims (5)

  The polypropylene block copolymer resin having at least an ethylene content of 5.5 to 9.9% by mass and 85 to 96 parts by mass and an ethylene content of 5% by mass or less were selected from a polypropylene random copolymer resin or a polypropylene resin. The crystal nucleating agent is 0.01 to 0.1 parts by mass and the acrylate antioxidant is 0.01 to 0.1 with respect to 100 parts by mass of the resin composition comprising 4 to 15 parts by mass of at least one polypropylene resin. A composition containing 0.05 to 1.0 parts by mass of at least one selected from mass parts, phosphorus antioxidants and phenolic antioxidants is melted from a die and extruded into a thin film, and a cooling roll A method for producing a polypropylene-based resin film, which is cooled and solidified by heating. A method for producing a polypropylene-based resin film, wherein the crystal nucleating agent comprises a cyclic organophosphate compound represented by the following general formula (I).

  The surface temperature of said cooling roll is 60-90 degreeC, The manufacturing method of the polypropylene resin film of Claim 1 or 2 characterized by the above-mentioned.   2. The melt extrusion is performed by using an extruder comprising at least a supply zone, a kneading zone and a metering zone, and the temperature of the kneading zone is set higher than the temperatures of the supply zone and the metering zone. The manufacturing method of the polypropylene resin film in any one of -3. The said acrylate antioxidant consists of a structure shown by following (II) Formula, The manufacturing method of the polypropylene resin film in any one of Claims 1-4 characterized by the above-mentioned.