JP2008050393A - Polypropylene-based resin film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a polypropylene-based resin film which has high heat-distortion resistance at a high temperature, for example, has excellent processing suitability such as adhesive processing, etc., a few fish eyes, improved handleability of film in spite of substantially not containing a lubricant and an antiblocking agent, for example, suitable as a substrate film of a protective film. <P>SOLUTION: The polypropylene-based resin film comprises a composition obtained by mixing, based on 100 pts.mass of a polypropylene-based resin composition containing ≥3.0 mass% of a rubber component, 0.01-0.1 pt.mass of a crystal nucleating agent, 0.01-0.1 pt.mass of an acrylate-based antioxidant and 0.05-1.0 pt.mass of at least one kind selected from a phosphorus-based antioxidant and a phenol-based antioxidant. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a polypropylene-based resin film, and in particular, has high heat deformation resistance at high temperatures, for example, excellent processing suitability such as adhesive processing, has little fish eye, and substantially contains a lubricant and an antiblocking agent. Although it is not included in the film, the film is easy to handle and, for example, relates to a polypropylene resin film suitable as a base film for a protective film.

  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.

  On the other hand, no mention is made regarding the effect of suppressing fisheye, but many techniques for enhancing the antioxidant effect by using two or more different types of antioxidants in combination are disclosed.

For example, a method in which a phenolic antioxidant and a phosphorus antioxidant are used in combination is disclosed (for example, see Patent Documents 23 to 26). Patent Document 23 improves coloration prevention, Patent Document 24 improves recyclability and temporal stability, Patent Document 25 improves coloration prevention during electron beam irradiation, and Patent Document 26 improves heat resistance stability.
Japanese Patent Laid-Open No. 7-23290 JP-A-10-202720 JP 2001-40113 A JP 2002-69248 A

Also, a method using a combination of a vitamin E antioxidant and a phosphorus antioxidant (see Patent Document 27), a method using a combination of a phenolic antioxidant, a phosphorus antioxidant and a sulfur antioxidant. (See Patent Document 28), a method of using a combination of a phenolic antioxidant and two types of phosphorus antioxidants (see Patent Document 29), a spirocoumarone compound, a polyhydric alcohol, a phosphorus antioxidant and a phenolic system A method of using together four kinds of antioxidants (see Patent Document 30) is disclosed. In Patent Document 27, the effect of reducing the addition amount is improved. In Patent Document 28, heat yellowing is improved. In Patent Document 29, yellowing of the coating film is improved. In Patent Document 30, recyclability and processing stability are improved. .
WO00 / 00540 Publication Japanese Patent Laid-Open No. 10-316808 JP 2003-292720 A JP 2002-60638 A

In recent years, attention has been focused on the fact that an acrylate-based antioxidant is added in a small amount and exhibits a good antioxidant effect (see, for example, 31 to 34).
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 33, in 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, a phenol oxidation Although the Example which uses together 3 types of antioxidants, an antioxidant and phosphorus antioxidant, is disclosed, the antiblocking agent is used in high concentration.

  The present invention is highly resistant to thermal deformation at high temperatures, for example, excellent in processability such as adhesive processing, has little fish eye, and has a film handling property despite being substantially free of lubricants and antiblocking agents. An object of the present invention is to provide a polypropylene-based resin film that is favorable and is suitable, for example, as a base film for a protective film.

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

  That is, in the present invention, 0.01 to 0.1 parts by mass of a crystal nucleating agent and 0.1 parts by mass of an acrylate antioxidant are added to 100 parts by mass of a polypropylene resin composition containing 3.0% by mass or more of a rubber component. 01-0.1 part by mass, comprising at least one selected from phosphorous antioxidants and phenolic antioxidants in a composition containing 0.05-1.0 parts by mass It is a polypropylene resin film.

  In this case, the content of the lubricant in the film is preferably 50 ppm or less.

  In this case, the content of the antiblocking agent in the film is preferably 50 ppm or less.

  Furthermore, in this case, the static friction coefficient of the film is preferably 0.95 or less.

  Furthermore, in this case, it is preferable that the stress at 5% elongation at 130 ° C. of the film is 1.5 MPa or more.

  Furthermore, in this case, the Young's modulus of the film is preferably 550 Mpa or more.

Furthermore, in this case, the number of fish eyes having a maximum diameter of 0.2 mm or more existing on the film surface is 0/1000 cm ² and the number of fish eyes having a maximum diameter of 0.1 mm or less is 100/1000 cm ² or less. It is preferable that

Furthermore, in this case, the crystal nucleating agent is preferably composed of a cyclic organophosphate compound represented by the following general formula (1).

Furthermore, in this case, it is preferable that the acrylate-based antioxidant has a structure represented by the following formula (II).

  Since the polypropylene resin film of the present invention is excellent in heat-resistant dimensional stability, for example, it is excellent in secondary processing such as adhesion processing, and even when subjected to treatment such as drying at a high temperature around 130 ° C. Since the occurrence of slack in the film and film sagging is suppressed, the productivity of the secondary processing can be improved, and the occurrence of defective products due to hot metal and film sagging can be suppressed. In addition, since the 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, the lubricant is transferred to an article to be packaged or an object to be protected. As a result, the contamination of these objects to be packaged and the objects to be protected is suppressed. In addition, since the 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, the antiblocking agent falls off due to wear or the like. Can be avoided, so that contamination, failure, etc. due to the fallout are suppressed. In addition, although it contains substantially no lubricant or anti-blocking agent, the surface roughness is appropriate, the film is slippery and blocking resistant, and the rigidity is excellent. Is excellent. 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 its improved heat-resistant dimensional stability, it has excellent impact strength, and the impact resistance added by being made of a rubber-containing polypropylene resin is maintained. And high reliability when used as a protective 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, the crystal nucleating agent is 0.01 to 0.1 parts by mass and the acrylate antioxidant is 0.01 parts by mass with respect to 100 parts by mass of the polypropylene resin composition containing 3.0% by mass or more of the rubber component. It is important to comprise a composition in which 0.05 to 1.0 part by mass of at least one selected from -0.1 part by mass, a phosphorus antioxidant and a phenolic antioxidant is blended.

  The composition of the polypropylene resin composition containing 3.0% by mass or more of the rubber component used in the present invention is not limited as long as it contains 3.0% by mass or more of the rubber component. Examples thereof include a blend of at least one of a homopolypropylene resin or a random copolymer polypropylene resin and a thermoplastic elastomer, a polypropylene block copolymer resin, and a mixture thereof. The block copolymer resin preferably contains 3.0% by mass or more of a rubber component. The amount of the rubber component is more preferably 4.0% by mass or more, further preferably 5.0% by mass or more, and particularly preferably 10.0% by mass or more. If the rubber component is less than 3.0% by mass, the impact resistance, slipping property and blocking resistance deteriorate, which is not preferable. On the other hand, the upper limit of the rubber component is preferably higher than the point of improvement in impact resistance, but is preferably 30% by mass or less because transparency deteriorates and visibility of a packaged article or a protected body is lowered. 28% or less is more preferable, and 25 mass% is further more preferable. When the rubber component amount exceeds 30% by mass, the film forming property is also lowered. The melting point is preferably from 155 to 166 ° C, particularly preferably from 160 to 165 ° C.

The homopolypropylene resin is not limited. Examples include the following.
A homopolypropylene having an MFR of 1 to 20 and a high melting point is preferred. The melting point is particularly preferably 160 to 166 ° C.

The copolymerized polypropylene resin is not limited. Examples include the following.
The random copolymer polypropylene resin preferably has an MFR of 1 to 20 and an ethylene content of 0.1 to 20% or less, particularly preferably an MFR of 0.1 to 3.
The melting point is preferably from 150 to 163 ° C, particularly preferably from 153 to 161 ° C.

  The polypropylene block copolymer resin is not limited, but 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 are copolymerized in a block manner. 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. In the case of the polypropylene block copolymer resin, the ethylene content is preferably 1.5 to 20% by mass, more preferably 2.0 to 15% by mass.

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.

  Examples of the thermoplastic elastomer include ethylene / propylene copolymer (EPR), ethylene / butene copolymer (EBR), ethylene / vinyl acetate (EVA), hydrogenated block copolymer, and the like. The hydrogenated block copolymer is composed of a polymer block A mainly containing at least one vinyl aromatic compound and a copolymer block B mainly containing at least one hydrogenated conjugated diene compound. For example, it is a hydrogenated block copolymer composed of ABA, BABA, BABA, and a mixture thereof. And what contains 10-40 mass% of vinyl aromatic compounds can be used as this hydrogenated block copolymer.

  As the vinyl aromatic compound constituting the hydrogenated block copolymer, for example, styrene, α-methylstyrene, and the like can be used, and styrene is particularly preferable. As the conjugated diene compound before hydrogenation constituting the hydrogenated conjugated diene compound, for example, butadiene, isoprene, or 1-3 pentadiene can be used, and butadiene is particularly preferable. The olefinic compound polymer block B is preferably obtained by hydrogenating 80%, preferably 90% or more of the aliphatic double bond based on the conjugated diene compound of the vinyl aromatic compound-conjugated diene compound block copolymer. A typical example of the copolymer is a styrene-ethylene-butylene-styrene copolymer, and the copolymerization amount of styrene is preferably 10 to 30% by weight. From the viewpoint of transparency, 10 to 20% by weight is preferred.

  The melt flow index (MI) of the thermoplastic elastomer (c) is preferably 5 g / 10 min or less, and preferably 0.2 to 5 g / 10 min in terms of impact resistance at low temperatures.

  Use of EPR and EBR is preferable from the viewpoint of cost performance.

  In the polypropylene resin film of the present invention, the content of the lubricant in the film is preferably 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, the polypropylene resin film of the present invention preferably has a static friction coefficient of 0.95 or less in a state where it does not substantially contain a lubricant or an antiblocking agent. 0.9 or less is more preferable, and 0.8 or less is more preferable. When the static friction coefficient exceeds 0.95, the slipperiness of the film is deteriorated and the handleability of the film is lowered. 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.

  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. 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. This characteristic can be imparted by the polypropylene block copolymer resin described above. The upper limit is preferably about 1.0 J from the balance with other characteristics.

  The method for imparting the above-mentioned slipperiness, blocking resistance and impact strength is not limited, but is greatly affected by the amount of rubber. It is preferably achieved as the overall effect of the preferred embodiments described herein including the amount of rubber.

  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 of the film at 130 ° C. is a measure of the heat-resistant dimensional stability of the film, and due to the correspondence, it is excellent in secondary processing such as adhesive processing, particularly around 130 ° C. Even when a treatment such as drying is performed at a high temperature, the generation of hot soot is suppressed, so that 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 compounding of the crystal nucleating agent described later 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 below 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 contains 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, the crystal nucleating agent is effective.

  In this invention, it is preferable to add 0.02-0.1 mass part as above-mentioned as a crystal nucleating agent with respect to 100 mass parts of all the polypropylene resin compositions mentioned above, and 0.3-0.8 mass part is more. preferable. Less than 0.02 parts by mass is not preferable because the effect of improving the heat-resistant dimensional stability described above is insufficient. 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.

Examples of the crystal nucleating agent include, but are not limited to, a crystal nucleating agent mainly composed of a metal salt of rosin, a sorbitol-based crystal nucleating agent, and a crystal nucleating agent composed of an aromatic organophosphate metal salt. The use of a crystal nucleating agent consisting of a cyclic organophosphate compound represented by the following general formula (1), which is a kind of crystal nucleating agent consisting of an organic phosphate metal salt, is preferred.

In the cyclic organophosphate compound represented by the above general formula (1), 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.).

  By including the above crystal nucleating agent, the heat-resistant dimensional stability of the obtained polypropylene resin film can be improved. The effect of improving the heat-resistant dimensional stability can be evaluated by, for example, stress at 5% elongation at 130 ° C.

  In the present invention, it is important for the polypropylene resin film of the present invention that the stress at 5% elongation at 130 ° C. is 1.5 MPa or more. 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.

  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.

  The above three kinds of antioxidants are not limited to one type each. Two or more of each type may be used in combination, and in addition to the above three types of antioxidants, for example, an antioxidant having another structure such as a sulfur-based antioxidant may be further used in combination.

  In combination, a high level of fisheye contamination suppression effect that is not obtained with a known combination of antioxidants is exhibited.

  As described above, Patent Document 6 discloses a polypropylene resin composition capable of reducing fish eyes by using a phenol-based antioxidant and a sulfur-based antioxidant as antioxidants. By using a plurality of antioxidants in combination with the above-mentioned method, it is expected that a high fisheye contamination suppression effect that cannot be obtained by a combination of conventionally known antioxidants, including the method of Patent Document 6, will be expected. The present invention was completed by finding no effect. It is presumed that the significant fisheye suppression effect was caused by the suppression of rubber component deterioration. Therefore, it is presumed that an effect that does not appear in the film formation using the homopolypropylene resin in Patent Document 17 in which the combined use of an antioxidant similar to the present invention is disclosed is exhibited.

  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 ¹ 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 ² 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 ³ 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 ⁴ 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 an antioxidant described later 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

  The polypropylene resin film of the present invention is an unstretched film formed by a known method such as a T-die method or an inflation method, and the thickness of the film is not particularly limited, but is generally 1 to 500 μm. A preferable thickness is selected as necessary.

  As film forming conditions for using the polypropylene resin composition of the present invention as an extruded film, for example, in the case of the T-die method, it is preferable to carry out at a die temperature of 200 ° C. to 250 ° C. and a cooling roll temperature of 60 to 90 ° C. 65-85 degreeC is more preferable. When the cooling roll temperature is 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.

  The polypropylene resin film of the present invention can be subjected to surface treatment such as corona discharge treatment or flame treatment by a method that is usually employed industrially.

Since the polypropylene-based resin film of the present invention has the characteristics as described above, it can be suitably used as a packaging for articles that are disliked from contamination caused by films such as food and precision parts, and as a protective film for various precision parts. However, it is preferable to use it as a surface protective film in which a pressure-sensitive adhesive layer is provided on at least one side of a polypropylene-based resin film because it also has excellent properties suitable for secondary processing such as pressure-sensitive adhesive processing. By the correspondence, the characteristics of the polypropylene resin film of the present invention described above can be effectively utilized, and the applicability in a wide field as a protective film is improved. In particular, for example, applications that prevent scratches, adhesion of dirt, contamination, etc. during the processing and assembly of electronic and precision products such as liquid crystal panels and polarizing plates, precision products, parts and related members, and connection of flexible printed circuit boards As a method of partially plating the terminal part, etc., a mask is formed by sticking an adhesive film to the non-plated part and then plating, or a resist film or etching resistance provided on the non-etched surface in the etching process when manufacturing the shadow mask Use in plating and etching processes such as methods for protecting the film, methods for protecting the surface of the semiconductor element by laminating a film on the surface without the circuit of the semiconductor element, and simplifying the process when assembling the semiconductor device, etc. Protection of various precision products and parts that are particularly demanding to suppress contamination and defects, and addition of such products and parts It can be suitably used as a protective film in and assembly process. Further, the polypropylene resin film of the present invention is excellent in heat-resistant dimensional stability, and in the above-mentioned adhesive processing, for example, even if the drying temperature in the drying process is increased, the occurrence of hot stagnation and film sagging is suppressed. It becomes possible to increase the productivity of adhesive processing. Moreover, generation | occurrence | production suppression of the inferior goods resulting from a hot bath or film sagging can be suppressed.

  The kind, thickness, adhesive strength, and the like of the pressure-sensitive adhesive layer are not limited. What is necessary is just to select suitably by market demand. Moreover, the lamination method of this adhesive layer is not limited. Any of the coating method and the extrusion laminating method may be used.

  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. Content of rubber component in block copolymer resin (1) 20 ° C. xylene soluble part 1 g of a sample is completely dissolved in 100 ml of boiling xylene, then cooled to 20 ° C. and left for 4 hours. Thereafter, this was separated into a precipitate and a solution, and the filtrate was dried and dried at 70 ° C. under reduced pressure. The weight was measured to determine the content% (weight).
(2) Component having a molecular weight of 50,000 or less (L-CXS) in a 20 ° C. xylene soluble part (CXS)
The molecular weight distribution of CXS was measured by GPC (gel permeation chromatography) under the following conditions, and L-CXS was determined by the following formula. The calibration curve was prepared using standard polystyrene. L-CXS = total CXS content × W / 100 (W is the content (wt%) of a component having a molecular weight of 50,000 or less in terms of polystyrene determined from GPC).
Model 150CV (Millipore Waters) Column Shodex M / S 80 Measurement temperature 145 ° C Solvent Orthodichlorobenzene Sample concentration 5mg / 8ml
Said L-CXS was made into rubber component content.

3. Ethylene content Measured by ¹³ C-NMR method according to the method described on page 616 of Polymer Handbook (published by Kinokuniya, 1995).

4). 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 °

5. Haze value Based on JIS-K-6714, it was measured using “Haze Tester J” manufactured by Toyo Seiki Seisakusho.

6). Blocking resistance The surface which contacted the cooling roll surface at the time of film forming was overlapped, and the tracing paper was overlapped on the overlapped surface and placed in a warm air dryer, and seasoned at 50 ° C. for 30 minutes. 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.

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

8. 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.

9. Young's modulus In accordance with JIS K7127, sample shape conforming to No. 1 type test piece (sample length 200 mm, sample width 15 mm, distance between chucks 100 mm), MD direction under conditions of crosshead speed 500 mm / min It measured at 23 degreeC about (film longitudinal direction).

10. Impact strength In accordance with ASTM D3420, the sample is cut to 55-60 cm in the vertical direction and 9-10 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.

11. Fisheye The molded film was cut 33.3 cm in the flow direction × 30 cm in the direction transverse to the flow direction, placed on a plate irradiated with a fluorescent lamp from below the film, and visually observed with transmitted light. Measure fish eyes of 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.

12 Extrudability The raw 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 grade ML -110, F.S. 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 The amount of the rubber component containing .28% by mass is 18.9% by mass, and the ethylene content is 9.0% by mass. The block copolymerized polypropylene resin (MFR = 2) is 89 parts by mass, and the ethylene content is 0.5% by mass. % Random copolymerized polypropylene resin (MFR = 7) and 10 parts by weight of bis (2,2′-methylene-bis (4,6-di-tert-butylphenyl) phosphate) -water as a cyclic organophosphate compound Homopolypropylene resin (M) containing 1% by mass of aluminum oxide salt (Asahi Denka Kogyo Co., Ltd., ADK STAB NA-21) A homopolypropylene resin containing 5 parts by mass of a masterbatch resin (M-1) containing a crystal nucleating agent consisting of FR = 7) and 5% by mass of Sumiser GS (manufactured by Sumitomo Chemical Co., Ltd.) which is an acrylate antioxidant ( 1 part by mass of a masterbatch resin (M-2) containing an acrylate antioxidant comprising MFR = 7) is melt-extruded by a T-die film forming machine, and an unstretched film having a thickness of 50 μm at a cooling roll temperature of 80 ° C. Obtained. In addition, the raw material resin composition was filtered by installing a filter having an average pore diameter of 40 μm between the extruder outlet and the die. 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. Further, using the polypropylene resin film, an adhesive was laminated by a coating method and dried at 130 ° C. with a tenter type dryer, but no generation of hot water was observed. Moreover, although the film was extended to 1.05 in the width direction and dried during the drying, the extensibility was good.

(Examples 2 and 3)
In the method of Example 1, Example 1 was used except that block copolymer polypropylene resins having a rubber component amount of 6.5 and 28.0% by mass and ethylene contents of 4.0 and 15% by mass, respectively, were used. The polypropylene resin films of Examples 2 and 3 were obtained in the same manner. The results are shown in Table 1.
The polypropylene resin films obtained in these examples had the same characteristics as the polypropylene resin film obtained in Example 1 and were 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.

(Example 6)
In the method of Example 1, instead of the block copolymerized polypropylene resin, a mixture comprising 81 parts by mass of a homopolypropylene resin (MFR = 3) and 11 parts by mass of an EPR-based thermoplastic elastomer (MFR = 0.7 g / 10 min). A polypropylene resin film of Example 4 was obtained in the same manner as in Example 1 except that the resin was used. The results are shown in Table 1.
The polypropylene-based resin film obtained in this example was inferior in extrudability and spreadability during adhesive processing. Other characteristics were high quality like the polypropylene resin film obtained in Example 1.

(Comparative Example 1)
Comparison is made in the same manner as in Example 1 except that the supply of 5 parts by mass of the master batch resin containing the crystal nucleating agent is stopped by the method of Example 1 and the supply amount of the random copolymer polypropylene resin is changed to 10 parts by mass. The polypropylene resin film of Example 1 was obtained. The results are shown in Table 1.
The polypropylene resin film obtained in this comparative example had a low F5 value at 130 ° C. and poor heat-resistant dimensional stability. Therefore, the occurrence of hot-spring was observed during the adhesive processing.

(Comparative Example 2)
The same method as in Example 1 except that the blending amount of the masterbatch resin containing the crystal nucleating agent in the method of Example 1 is 1 part by mass and the supply amount of the random copolymer polypropylene resin is changed to 9 parts by mass. A polypropylene resin film of Comparative Example 2 was obtained. The results are shown in Table 1.
The polypropylene resin film obtained in this comparative example had a low F5 value at 130 ° C. and poor heat-resistant dimensional stability. Therefore, the occurrence of hot-spring was observed during the adhesive processing.

(Comparative Example 3)
Bis (2,2′-methylene-bis (4,6-di-tert-butylphenyl) phosphate) -aluminum hydroxide salt in a masterbatch resin containing a crystal nucleating agent by the method of Example 1 (Asahi Denka Kogyo) A polypropylene resin film of Comparative Example 3 was obtained in the same manner as in Example 1 except that the concentration of ADK STAB NA-21 manufactured by Corporation was changed to 3% by mass. The results are shown in Table 2.
The polypropylene resin film obtained in this comparative example had low impact strength and was inferior in impact resistance.

(Comparative Example 4)
In the method of Example 1, the supply of the masterbatch resin (M-2) containing an acrylate antioxidant was stopped, and Irgafos 168 (manufactured by Ciba Specialty Chemicals Co., Ltd.) was replaced with a block copolymerized polypropylene resin. A polypropylene resin film of Comparative Example 4 was obtained in the same manner as in Example 1 except that the amount was increased to 0.28% by mass and the supply of the random copolymer polypropylene resin was changed to 10% by mass. The results are shown in Table 2.
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. Moreover, the slipperiness was also inferior. Therefore, the pressure-sensitive adhesive film produced using the polypropylene resin film obtained in this comparative example also contained a lot of fish eyes and was of low quality.

(Comparative Example 5)
In the method of Example 1, a block copolymerized polypropylene resin in which the blending of a phosphorus antioxidant and a phenolic antioxidant was stopped was used. Instead, Sumizer GS (Sumitomo Chemical Co., Ltd.), which is an acrylate antioxidant, was used. Manufactured) The supply amount of the masterbatch resin (M-2) containing an acrylate antioxidant comprising 5% by mass of a homopolypropylene resin (MFR = 7) is increased to 3 parts by mass to supply a random copolymer polypropylene resin. A polypropylene resin film of Comparative Example 3 was obtained in the same manner as in Example 1 except that the amount was changed to 8 parts by mass. 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 slipperiness was also inferior. Furthermore, 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 instead, Irgafos was supplied to the block copolymerized polypropylene resin. 168 (manufactured by Ciba Specialty Chemicals Co., Ltd.) was increased to 0.28% by mass, and the random copolymerized polypropylene resin supply was changed to 11% by mass, and compared in the same manner as in Example 1. The polypropylene resin film of Example 4 was obtained. 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 poor heat-resistant dimensional stability. Therefore, the occurrence of hot-spring was observed during the adhesive processing. Moreover, there were many fish eyes and it was low quality. Furthermore, the slipperiness was also inferior.

(Comparative Example 7)
In the method of Example 1, a polypropylene resin film of Comparative Example 6 was obtained in the same manner as in Example 1 except that a homopolypropylene resin was used instead of the block copolymerized polypropylene resin. The results are shown in Table 2.
The polypropylene resin film obtained in this comparative example was inferior in slipperiness. Moreover, impact strength was low and impact resistance was inferior. Furthermore, the spreadability at the time of adhesive processing was also inferior.

(Comparative Example 8)
In the method of Comparative Example 4, a polypropylene resin film of Comparative Example 9 was obtained in the same manner as in Comparative Example 2, except that the cooling roll temperature was changed to 50 ° C. 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 had a low F5 value at 130 ° C. and poor heat-resistant dimensional stability. Therefore, the occurrence of hot-spring was observed during the adhesive processing.

(Comparative Example 9)
In the method of Comparative Example 2, a polypropylene resin film of Comparative Example 4 was obtained in the same manner as in Comparative Example 2, except that the cooling roll temperature was changed to 95 ° C. The results are shown in Table 2.
In this comparative example, in addition to the problem of the polypropylene resin film obtained in Comparative Example 2, the cooling roll temperature was too high, and the touch roll mark of the cooling roll was generated, and the appearance of the film was deteriorated.

  Since the polypropylene resin film of the present invention is excellent in heat-resistant dimensional stability, for example, it is excellent in secondary processing such as adhesion processing, and even when subjected to treatment such as drying at a high temperature around 130 ° C. Since the occurrence of slack in the film and film sagging is suppressed, the productivity of the secondary processing can be improved, and the occurrence of defective products due to hot metal and film sagging can be suppressed. In addition, since the 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, the lubricant is transferred to an article to be packaged or an object to be protected. As a result, the contamination of these objects to be packaged and the objects to be protected is suppressed. In addition, since the 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, the antiblocking agent falls off due to wear or the like. Can be avoided, so that contamination, failure, etc. due to the fallout are suppressed. In addition, although it contains substantially no lubricant or anti-blocking agent, the surface roughness is appropriate, the film is slippery and blocking resistant, and the rigidity is excellent. Is excellent. 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, it has excellent impact strength, and the impact resistance added by being made of a rubber-containing polypropylene resin is maintained. And high reliability when used as a protective 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 (9)

  For 100 parts by mass of the polypropylene resin composition containing 3.0% by mass or more of the rubber component, the crystal nucleating agent is 0.02 to 0.1 parts by mass, and the acrylate antioxidant is 0.01 to 0.1 parts by mass. A polypropylene resin film comprising a composition in which 0.05 to 1.0 parts by mass of at least one selected from a part, a phosphorus antioxidant and a phenolic antioxidant are blended.   It is a polypropylene resin film of Claim 1, Comprising: Content of the lubricant in the said film is 50 ppm or less, The polypropylene resin film characterized by the above-mentioned.   It is a polypropylene resin film of Claim 1, Comprising: Content of the antiblocking agent in the said film is 50 ppm or less, The polypropylene resin film characterized by the above-mentioned.   It is a polypropylene resin film of Claim 1, Comprising: The static friction coefficient of the said film is 0.95 or less, The polypropylene resin film characterized by the above-mentioned.   2. The polypropylene resin film according to claim 1, wherein a stress at 5% elongation at 130 ° C. of the film is 1.5 MPa or more. 3.   It is a polypropylene resin film of Claim 1, Comprising: The Young's modulus of the said film is 550 Mpa or more, The polypropylene resin film characterized by the above-mentioned. 2. The polypropylene resin film according to claim 1, wherein the number of fish eyes having a maximum diameter of 0.2 mm or more present on the film surface is 0/1000 cm ² and the fish eye having a maximum diameter of 0.1 mm or less. Is a polypropylene resin film, wherein the number is 100 pieces / 1000 cm ² or less. It is a polypropylene resin film of Claim 1, Comprising: The said crystal nucleating agent consists of a cyclic organophosphate ester compound represented by following General formula (1), The polypropylene resin film characterized by the above-mentioned.

The polypropylene resin film according to any one of claims 1 to 8, wherein the acrylate antioxidant has a structure represented by the following formula (II).