JP2001072813A - Polypropylene-based resin composition and its oriented film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polypropylene-based resin composition which is suitable for producing oriented polypropylene-based films that have excellent transparency, excellent blocking resistance, excellent appearance and excellent falling-off resistance, and to provide an oriented polypropylene-based resin film using the polypropylene-based resin composition. SOLUTION: This polypropylene-based resin composition comprises (A) 100 pts.wt. of a crystalline propylenic polymer, (B) 0.05 to 5 pts.wt. of organic particles having a surface polarity of >=45 dyne/mm, a particle diameter variation coefficient of <=30%, an average particle diameter of 0.3 to 10 μm, and a strength of <=10 kgf/mm2, when the particles are deformed at a rate of 10%, and (C) 0.01 to 1 pt.wt. of an acid-modified polyolefin-based resin having an acid value of 1.0 to 100 mgKOH/g defined by JIS K0070. The oriented polypropylene-based resin film comprises the polypropylene-based resin composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polypropylene resin composition suitable for producing a stretched polypropylene film having excellent transparency, blocking resistance, appearance, and falling resistance, and a stretched polypropylene composition using the same. About the film.

[0002]

2. Description of the Related Art Stretched polyolefin films, especially stretched polypropylene films, have excellent transparency,
Due to its mechanical properties, it is used in a wide range of applications such as food packaging and textile packaging. However, the stretched polypropylene film itself has a drawback of being inferior in blocking resistance. In order to solve such problems, many studies have been made so far, and a method of adding inorganic fine particles (Japanese Patent Publication No. 52-16134) and a method of adding organic fine particles (Japanese Patent Publication No. Sho 50-50). A method of adding an antiblocking agent such as JP-A-36262) has been proposed.

[0003] However, when inorganic fine particles are used as an anti-blocking agent, voids are generated at the time of film stretching due to insufficient affinity between the inorganic fine particles and the polyolefin-based resin, resulting in poor transparency. Getting worse.
Furthermore, there is a problem that surface scratch resistance due to rubbing of the films due to the projection shape and hardness of the film surface, so-called scratch resistance becomes poor. Also,
As a method of adding organic fine particles, there is a method of using crosslinked polymethyl methacrylate particles or the like as the organic fine particles (JP-A-5-214120), but the affinity with the polyolefin resin is insufficient. Due to the spherical shape, voids are generated during film stretching and the transparency is deteriorated, and the anti-blocking agent falls off during film formation or secondary processing, resulting in process contamination and deterioration of film physical properties. ing.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polypropylene resin composition suitable for producing a stretched polypropylene film having excellent transparency, blocking resistance, appearance, and falling resistance, and a method for using the same. To provide a stretched polypropylene resin film.

[0005]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have used organic fine particles having a specific strength, surface polarity and particle size distribution as an anti-blocking agent, and The inventors have found that the above problems can be solved by using a modified polyolefin as a compatibilizer, and have reached the present invention. That is, the present invention is a polypropylene-based resin composition comprising the following components (A), (B), and (C). (A) 100 parts by weight of a crystalline propylene polymer (B) Average particle size having the following characteristics is 0.3 to 10 μm
0.05 to 5 parts by weight of organic fine particles of (1) Strength of 10 kgf when the particles are deformed by 10%
/ Mm ² or less. (2) It has a surface polarity of 45 dyne / mm or more. (3) The variation coefficient of the particle diameter calculated from the following equation is 30% or less. Coefficient of variation of particle size (%) = standard deviation of particle size (μm) / average particle size (μm) × 100 (C) The acid value specified by JIS K0070 is 1.0 to 1.0.
100mgKOH / g acid-modified polyolefin resin
0.01 to 1 part by weight Further, it is a stretched polypropylene-based resin film obtained by stretching a film made of the above composition at least uniaxially.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described specifically. 1. Crystalline Polypropylene-Based Resin The crystalline propylene-based resin used in the present invention is a propylene homopolymer, or propylene having a majority polymerization ratio and another α-olefin (ethylene, butene, hexene, 4-
A random, block or graft copolymer with an unsaturated carboxylic acid or a derivative thereof (such as acrylic acid or maleic anhydride) or an aromatic vinyl monomer (such as styrene). The isotactic index of such a crystalline propylene polymer (I.
I) is preferably 40% or more, more preferably 60% or more, particularly preferably 80% or more. Therefore, it is most preferable to use a propylene homopolymer. I is 9
It is preferable to use 0% or more, especially 95% or more, particularly 98% or more, from the viewpoints of the stiffness of the film, the paper dropping property of the film feeding portion, and the suitability for a high-speed automatic packaging machine. In addition, the melt flow rate (MFR) is 0.1.
Those having 5 to 10 g / 10 min, particularly 1 to 5 g / 10 min are preferable. Even these crystalline propylene polymers alone,
Alternatively, it may be used as a mixture of plural kinds of polymers, or may be a resin containing a crystalline propylene-based polymer as a main component.

[0007] 2. Organic Fine Particles The average particle diameter of the organic fine particles used in the present invention is from 0.3 to 1
0 μm, preferably 0.5 to 5 μm. If the average particle size is less than 0.3 μm, sufficient blocking resistance cannot be imparted when formed into a film. The average particle size is 1
If it exceeds 0 μm, a large stress concentration occurs at the interface between the organic fine particles and the polyolefin at the time of stretching the film, thereby causing interface delamination to generate voids and deteriorate transparency.

[0008] The organic fine particles used in the present invention further have the following characteristics. (1) The strength when the particles are deformed by 10% is 10 kgf
/ Mm ² or less, preferably 8 kgf / mm ² or less. Strength when deformed by 10% is 10 kgf / mm ²
If it exceeds, the scratch resistance deteriorates.

(2) The surface polarity of the organic fine particles is 45 dy.
ne / mm or more, preferably 50 dyne / mm or more. If the surface polarity is less than 45 dyne / mm, the affinity with the acid-modified polyolefin is poor, voids are generated at the interface between the organic fine particles and the polyolefin during film stretching, and the transparency is deteriorated and the fine particles fall off.

The method for imparting a surface polarity of 45 dyne / mm or more to the organic fine particles is not particularly limited, but the following methods are exemplified. A method of incorporating a monomer having a hydrophilic functional group into the composition when polymerizing organic fine particles. A method in which a monomer having a hydrophilic functional group on the surface of fine particles is polymerized by a method such as a seed polymerization method or a graft polymerization method. A method of coating the surface of organic fine particles with a resin having a hydrophilic functional group. A method of introducing a hydrophilic functional group by surface treatment of fine particles.

Examples of such a hydrophilic functional group include, for example, -COOX (X is -H, -K, -Na, -N
_{H 4), - OH, -NH} 2, -SO 3 X (X is, -H,
—K, —NH ₄ ), —O—R—H (R is a group derived from an alkylene oxide) and the like. Specific examples of the monomer having a hydrophilic functional group as described above include acrylic acid, methacrylic acid, glycidyl methacrylate, 2-hydroxyethyl methacrylate, N-methylolacrylamide, N, N-dimethylacrylamide, diacetoneacrylamide, and acrylic. Acrylic monomer such as isocyanate, o-aminostyrene, m
Styrene-based monomers such as -aminostyrene and p-aminostyrene.

Examples of the monomer copolymerizable with the monomer having a hydrophilic functional group or the monomer which polymerizes fine particles having a hydrophilic functional group on the surface thereof include methyl acrylate, ethyl acrylate and n-butyl acrylate. , Isobutyl acrylate, dodecyl acrylate, stearyl acrylate, 2-ethylhexyl acrylate, tetrahydrofurfuryl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n methacrylate -(Meth) acrylic monomers such as octyl, dodecyl methacrylate, stearyl methacrylate, 2-ethylhexyl methacrylate, methyl 5-hexenoate, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene α- methyl styrene, p- methoxystyrene, p-tert-butylstyrene, p-
Styrene-based monomers such as phenylstyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene,
Examples include ethylene, propylene, butylene, vinyl chloride, vinyl acetate, acrylonitrile, acrylamide, N-vinylpyrrolidone, and the like. It is also possible to use these monomers in combination.

Further, a crosslinking monomer can be copolymerized if necessary. Examples of the crosslinkable monomer include ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, decaethylene glycol diacrylate, pentadecaethylene glycol diacrylate, diacrylic acid 1,
3-butylene, allyl acrylate, pentaerythritol tetraacrylate, diethylene glycol diacrylate phthalate, pentacontaector ethylene glycol dimethacrylate, pentacontaector ethylene glycol diacrylate, tetraethylene glycol diacrylate, tetraethylene glycol dimethacrylate, tri Pentaerythritol acrylate, pentaerythritol trimethacrylate, 1,1,1-trishydroxymethylethane diacrylate, 1,1,1-trishydroxymethylethane triacrylate, 1,1,1 triacrylate
-Trishydroxymethylpropane, trimethylolpropane triacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, decaethylene glycol dimethacrylate, pentadecaethylene glycol dimethacrylate, dimethacrylic acid 1 (Meth) acrylic monomers such as 1,3-butylene, allyl methacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetramethacrylate, diethylene glycol phthalate dimethacrylate, and fragrances such as divinylbenzene, divinylnaphthalene, and derivatives thereof Group divinyl compound,
Crosslinking agents such as N, N-divinylaniline, divinyl ether, divinyl sulfide, divinyl sulfonic acid, etc., as well as polybutadiene, polyisoprene, unsaturated polyester and the like.

(3) The coefficient of variation of the particle size of the organic fine particles is 3
0% or less, preferably 20% or less. Coefficient of variation is 3
If it exceeds 0%, voids are generated at the time of stretching the film due to the influence of coarse particles, resulting in deterioration in transparency and poor appearance. Here, the variation coefficient of the particle size is a value obtained by dividing the standard deviation of the particle size obtained from the number distribution by the average particle size obtained from the number distribution, that is, a value obtained by the following equation. Coefficient of variation of particle size (%) = Standard deviation of particle size (μm) / Average particle size (μm) × 100 The variation coefficient of particle size is a value indicating variation in particle size distribution. Is broad. The shape of the crosslinked polymer fine particles is not particularly limited, but is preferably substantially spherical.

3. Acid-modified polyolefin-based resin The acid-modified polyolefin-based resin used in the present invention is a polyolefin-based resin in which at least a part of the terminals is acid-modified, and has an acid value defined by JIS K0070 of 1.0 to 1.0.
100 mg KOH / g, preferably 5 to 60 mg KOH
/ G. When the acid value is less than 1.0 mgKOH / g, the transparency and the falling resistance deteriorate. On the other hand, 100mgK
If it exceeds OH / g, operability deteriorates. Examples of polyolefins include homopolymers or copolymers of propylene, ethylene, butene-1, hexene-1, 4-methylpentene-1 and the like, and mixtures of these polymers.
Especially, it is preferable to use low molecular weight polypropylene.

The low-molecular-weight acid-modified polypropylene is an acid-modified polypropylene having a number-average molecular weight of 800 to 20,000, preferably 1,000 to 18,000 (hereinafter sometimes abbreviated simply as "acid-modified low-molecular weight PP"). ). The acid-modified low-molecular-weight PP is obtained by chemically adding an unsaturated carboxylic acid and / or an anhydride thereof described below to low-molecular-weight polypropylene having a terminal double bond, or by reducing the molecular weight of ordinary acid-modified propylene. And at least a part of the terminal is acid-modified. The acid-modified polypropylene obtained by the acid modification generally has a softening point of 130 to 170 ° C, preferably 140 to 160 ° C.

Preferred low molecular weight polypropylene having a terminal double bond is 1 to 1 per 1,000 carbons.
It has 0, preferably 2 to 7 terminal double bonds, and has a number average molecular weight of 800 to 20,000, preferably 1,000 to
18,000. If the terminal double bond is less than the above range, desired acid modification may not be performed. If the terminal double bond exceeds the above range, the heat resistance of the acid-modified low molecular weight PP tends to decrease. . Further, when the number average molecular weight exceeds the above range, the prevention of the fine particles from falling tends to decrease.

The above-mentioned acid modification is carried out by a melt grafting method or a solution grafting method. In the melt grafting method, the reaction temperature is usually 100 to 270 ° C., preferably 130 to 240 ° C., usually 0.5 to 30 hours. It is preferably carried out under the conditions of a reaction time of 1 to 20 hours. In the solution grafting method, after completely dissolved in xylene, a peroxide is used in combination, and the reaction with an unsaturated carboxylic acid and / or an anhydride thereof is usually performed at 120 to 180 ° C, preferably 140 to 180 ° C.
The reaction is carried out at a reaction temperature of 160 ° C., usually for a reaction time of 1 to 20 hours, preferably 3 to 15 hours. Then, a precipitate is obtained using a large amount of acetone or the like. The product obtained by the acid modification contains generally 0.01 to 20%, preferably 0.05 to 15%, particularly preferably 0.1 to 10% by weight of unsaturated carboxylic acid and / or anhydride thereof.
Is desirably contained at a ratio of

The unsaturated carboxylic acid as a modifier includes:
Acrylic acid, methacrylic acid, maleic acid, fumaric acid,
Examples thereof include itaconic acid, citraconic acid, and nadic acid. Further, as the unsaturated carboxylic anhydride,
Maleic anhydride, itaconic anhydride, citraconic anhydride,
Allyl succinic anhydride and nadic anhydride can be exemplified. Among these, it is preferable to use maleic anhydride. Such acid-modified polyolefins may be those obtained by diluting directly modified ones with unmodified ones, and may be appropriately selected from commercially available ones and used, for example, Umex series (Sanyo Chemical Industries, Ltd.) )
Commercially available maleic anhydride-modified polypropylene.

4. Polypropylene-based resin composition The polypropylene-based resin composition of the present invention is a composition comprising the polypropylene-based resin, the organic fine particles, and the acid-modified polyolefin-based resin. 0.05 to 5 parts by weight, preferably 0.07 to 3 parts by weight, and 0.01 to 1 part by weight of an acid-modified polyolefin resin. If the amount of the organic fine particles is less than 0.05 part by weight, sufficient slipperiness and blocking resistance cannot be imparted. If the amount exceeds 5 parts by weight, the transparency deteriorates. In addition, acid-modified polyolefin resin is 0.0%
If the amount is less than 1 part by weight, the transparency and the resistance to falling off are not sufficiently improved, and if it exceeds 5 parts by weight, the operability during film formation deteriorates.

As a method of adding organic fine particles and an acid-modified polyolefin resin to a polypropylene resin,
Any method may be used as long as the organic fine particles and the acid-modified polyolefin resin are uniformly dispersed.For example, after mixing the polypropylene resin, the organic fine particles and the acid-modified polyolefin resin with a ribbon blender, a Henschel mixer, or the like, A method in which the mixture is melt-kneaded with an extruder is used. At that time, additives such as an antioxidant, an antistatic agent, a neutralizing agent, and a lubricant can be appropriately compounded. Further, the polypropylene-based resin composition of the present invention may have a final composition in a stretched film within the above-mentioned composition range.For example, a high-concentration masterbatch is prepared in advance, and a method such as dry blending is used during stretched film production. It is possible to dilute to a predetermined concentration. Furthermore, the stretched film according to the present invention may be a multilayer film having two or more layers, and it is more preferable to use the resin composition of the present invention for at least one surface layer. In this case, the composition of the resin constituting the surface layer of the multilayer film may be within the composition range of the resin composition.

5. Film The stretched film of the present invention is produced by melt-extruding the polypropylene-based resin composition obtained above, cooling it, and then stretching it in at least one axial direction by a known method.
The thickness of the film of the present invention is not particularly limited.
μm or less, preferably 5 to 100 μm, more preferably 10 to 50 μm. The stretched film of the present invention may be used as a single-layer film or a laminated film. Examples of a method for obtaining a laminated film include a multilayer coextrusion method and a dry lamination method.

[0023]

EXAMPLES The present invention will be described in more detail with reference to the following Examples and Comparative Examples, but the present invention is not particularly limited by the following Examples. In addition, the measured value of each item in the detailed description of the present invention and the examples was measured by the following method. (1) Average particle size and variation coefficient of particle size: Organic fine particles were mixed with an anionic surfactant so as to have a concentration of about 10%. The fine particles were sufficiently dispersed using an ultrasonic disperser. The state of dispersion was observed with a microscope, and if aggregated, a surfactant was added and dispersed. The average particle diameter and the standard deviation of the obtained dispersion were measured using a Coulter Multitizer manufactured by Coulter Corporation. Here, values calculated from the number distribution were used for the average particle diameter and the variation coefficient. (2) Surface polarity: 1 g of organic fine particles were placed between two glass plates, and a load of 2 kg was applied and left at room temperature for 2 hours.
After the standing, the upper glass plate was removed, and 1 ml of a wetting index standard solution (manufactured by Wako Pure Chemical Industries, Ltd.) was dropped on the fine particles to evaluate. The number of the lowest standard solution in which a water droplet was retained for 2 seconds was used as a measure of the surface polarity. (3) Fine particle strength: using a micro compression tester (MCTM-201) manufactured by Shimadzu Corporation and a load speed of 0.014.
The load was applied when the organic fine particles were deformed at 5 gf / s and the organic fine particles were deformed by 10%. The measurement was performed 10 times, and the average value was used.

(4) HAZE: HAZE: Measured according to JIS K7105 and used as a measure of transparency. (5) Blocking strength: the corona-treated surfaces of the two films were stacked so that the contact area was 40 cm ² ,
Place between two glass plates and apply a load of 2 kg to 50
After leaving for 24 hours in an atmosphere of 50 ° C. and a humidity of 50%, the film was peeled off at a tensile speed of 150 mm / min using a tensile tester, and the maximum load was read to evaluate. (6) Drop-off resistance: A 100 × 300 mm film was sagged on a glass plate and fixed without wrinkling. Also, 10
0 × 50 mm black paper is wrapped with gauze in triple 10
It was wrapped around a rod having a contact area of 0 × 10 mm and fixed. Both were rubbed for 10 minutes under the conditions of an amplitude of 200 mm and a shaking speed of 72 times / min. The adhesion of the antiblocking agent to the black paper was visually evaluated according to the following criteria. ：: Almost no adhesion was observed. Δ: Slight adhesion is observed. X: Adhesion is observed. (7) Scratch resistance: A 100 × 300 mm film (film A) was fixed on a glass plate without sagging and without wrinkling. Further, a 100 × 300 mm film (film B) was placed on the film A, and a 200 g weight was placed on the center of the film B so as to be in contact with the area of 5 × 5 cm. Next, the film B was rubbed 100 times between 10 cm by moving horizontally. HAZE before and after rubbing of the film A was measured, and the difference ΔHAZE was used as a measure of the scratch resistance of the film.
The smaller the value, the better.

Example 1 (1) Preparation of Organic Fine Particles Emulsion polymerization was carried out with methacrylic acid / methyl methacrylate / trimethylolpropane trimethacrylate in a weight ratio of 5/85/10. Table 1 shows the properties of the obtained organic fine particles. (2) Preparation of polypropylene resin composition Polypropylene powder 1 having an MFR of 2.3 g / 10 minutes
0.18 parts by weight of BHT (2,6-di-tert-butylhydroxytoluene), 0.1 part by weight of calcium stearate, Ir1 manufactured by Ciba-Geigy Co., Ltd.
010 0.05 parts by weight, 2000 ppm of the organic fine particles obtained in (1), Umex 1001 manufactured by Sanyo Chemical Industries, Ltd. as an acid-modified polyolefin resin (acid value: 2
(6 mg KOH / g) 0.1 part by weight was added, mixed with a Henschel mixer, granulated with a 65 mmφ twin screw extruder, and pelletized. Table 2 shows the composition ratio of the resin composition. (3) Preparation of biaxially stretched film The obtained pellet is melt-extruded at 280 ° C from a T-die,
The film was quenched with a chill roll at 30 ° C. to obtain a film.
, Stretched 9 times in the horizontal direction at 155 ° C, thickness 20μm
After obtaining a stretched film, a corona treatment was applied to one surface.
Table 3 shows the evaluation results of the obtained films.

Example 2 (1) Preparation of Organic Fine Particles 2-hydroxyethyl methacrylate / methyl methacrylate / trimethylolpropane trimethacrylate
Emulsion polymerization was performed at a weight ratio of 85/10. Table 1 shows the properties of the obtained fine particles. (2) Preparation of biaxially stretched film Example 1 was repeated except that the organic fine particles obtained in (1) were used.
A polypropylene-based resin composition was prepared in the same manner as described above, and subsequently a stretched film having a thickness of 20 μm was obtained. Table 3 shows the evaluation results of the obtained films.

Example 3 (1) Preparation of organic fine particles Emulsion polymerization of methacrylic acid / methyl methacrylate / trimethylolpropane trimethacrylate was carried out at a weight ratio of 5/85/10. Table 1 shows the properties of the obtained fine particles. (2) Preparation of polypropylene resin composition Polypropylene powder 1 having an MFR of 2.3 g / 10 minutes
0.18 parts by weight of BHT, 0.1 part by weight of calcium stearate, Ir1 manufactured by Ciba Geigy
010 0.05 parts by weight, 3000 ppm of the organic fine particles obtained in (1), Umex 1001 manufactured by Sanyo Chemical Industries, Ltd. as an acid-modified polyolefin resin (acid value: 2
(6 mg KOH / g) 0.1 part by weight was added, mixed with a Henschel mixer, granulated with a 65 mmφ twin screw extruder, and pelletized. Table 2 shows the composition ratio of the resin composition. (3) Preparation of biaxially stretched film The obtained pellet is melt-extruded at 280 ° C from a T-die,
The film was quenched with a chill roll at 30 ° C. to obtain a film.
, Stretched 9 times in the horizontal direction at 155 ° C, thickness 20μm
After obtaining a stretched film, a corona treatment was applied to one surface.
Table 3 shows the evaluation results of the obtained films.

Example 4 (1) Preparation of Organic Fine Particles Emulsion polymerization of 2-methacrylamide / methyl methacrylate / trimethylol trimethacrylate in a weight ratio of 5/85/10 was carried out. Table 1 shows the properties of the obtained fine particles. (2) Preparation of biaxially stretched film Example 1 was repeated except that the organic fine particles obtained in (1) were used.
A polypropylene-based resin composition was prepared in the same manner as described above, and subsequently a stretched film having a thickness of 20 μm was obtained. Table 3 shows the evaluation results of the obtained films.

Comparative Example 1 (1) Preparation of Organic Fine Particles Emulsion polymerization of methyl methacrylate / trimethylolpropane trimethacrylate was carried out at a weight ratio of 95/5. Table 1 shows the properties of the obtained fine particles. (2) Preparation of biaxially stretched film Example 1 was repeated except that the organic fine particles obtained in (1) were used.
A polypropylene-based resin composition was prepared in the same manner as described above, and subsequently a stretched film having a thickness of 20 μm was obtained. Table 3 shows the evaluation results of the obtained films.

Comparative Example 2 (1) Preparation of Organic Fine Particles / Preparation of Polypropylene Resin Composition Organic fine particles were prepared in the same manner as in Example 1, and the procedure of Example 1 was repeated except that no acid-modified resin was added. A polypropylene resin composition was prepared. (2) Preparation of biaxially stretched film A stretched film having a thickness of 20 µm was obtained in the same manner as in Example 1 using the polypropylene-based resin composition obtained in (1). Table 3 shows the evaluation results of the obtained films.

Comparative Example 3 (1) Preparation of Organic Fine Particles Suspension polymerization of methacrylic acid / methyl methacrylate / trimethylolpropane trimethacrylate was carried out at a weight ratio of 2/88/10. Table 1 shows the properties of the obtained fine particles. (2) Preparation of biaxially stretched film Example 1 was repeated except that the organic fine particles obtained in (1) were used.
A polypropylene-based resin composition was prepared in the same manner as described above, and subsequently a stretched film having a thickness of 20 μm was obtained. Table 3 shows the evaluation results of the obtained films.

Comparative Example 4 (1) Preparation of Organic Fine Particles Suspension polymerization of methacrylic acid / methyl methacrylate / trimethylolpropane trimethacrylate was carried out at a weight ratio of 5/85/10. Table 1 shows the properties of the obtained fine particles. (2) Preparation of polypropylene-based resin composition MFR 2.3 g / 10 min polypropylene powder 10
0 parts by weight, 0.18 parts by weight of BHT, 0.1 parts by weight of calcium stearate, Ir10 manufactured by Ciba-Geigy
10 0.05 parts by weight, 3000 ppm of the organic fine particles obtained in (1), Umex 1001 manufactured by Sanyo Chemical Industries, Ltd. as an acid-modified polyolefin resin (acid value: 26
(mgKOH / g) 0.1 part by weight was added, mixed with a Henschel mixer, granulated with a 65 mmφ twin screw extruder, and pelletized. Table 2 shows the composition ratio of the resin composition. (3) Preparation of biaxially stretched film The obtained pellet is melt-extruded at 280 ° C from a T-die,
The film was quenched with a chill roll at 30 ° C. to obtain a film.
, Stretched 9 times in the horizontal direction at 155 ° C, thickness 20μm
After obtaining a stretched film, a corona treatment was applied to one surface.
Table 3 shows the evaluation results of the obtained films.

Comparative Example 5 A biaxially stretched film was obtained in the same manner as in Example 1 except that non-melting type silicone fine particles (Tospearl 120, manufactured by Toshiba Silicone Co., Ltd.) were used instead of the organic fine particles used in Example 1. Was. The properties of the non-molten silicone fine particles are shown in Table 1, and the evaluation results of the obtained film are shown in Table 3.

Comparative Example 6 In place of the organic fine particles used in Example 1, amorphous silica fine particles (Silicia 44, manufactured by Fuji Silysia Chemical Ltd.)
A biaxially stretched film was obtained in the same manner as in Example 1, except that 6) was changed to 0.03 parts by weight. Table 1 shows the properties of the amorphous silica fine particles, and Table 3 shows the evaluation results of the obtained films.

[0035]

[Table 1]

[0036]

[Table 2]

[0037]

[Table 3]

As is clear from Table 3, the biaxially stretched films obtained in Examples 1 to 4 have excellent transparency,
It showed blocking properties, falling resistance and scratch resistance, and was of high quality. On the other hand, the surface polarity is 45 dyne / mm ²
The biaxially stretched film obtained by using the fine particles having a particle size of less than 10 was inferior in falling resistance (Comparative Examples 1 and 3). The film in which no acid-modified polypropylene was used had poor shedding resistance (Comparative Example 2). The biaxially stretched film obtained using fine particles having a coefficient of variation exceeding 30% had slightly poor transparency and blocking resistance (Comparative Example 4). 10% particles
A biaxially stretched film obtained by using fine particles having a strength of more than 10 kgf / mm ² when deformed has a falling resistance,
The scratch resistance was poor (Comparative Example 5). The biaxially stretched film obtained using the inorganic fine particles was inferior in transparency and blocking property, and slightly inferior in falling-off resistance and scratch resistance (Comparative Example 6).

[0039]

The polypropylene resin composition of the present invention and the stretched film using the same contain organic fine particles having specific particle properties and surface properties and an acid-modified polyolefin resin, so that transparency and blocking are obtained. Excellent in industrial properties and extremely industrially useful as various packaging films. In addition, since the antiblocking agent has excellent resistance to falling off, there is no process contamination, and it is excellent in operability and post-processability.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F071 AA20 AA33 AA78 AD02 AH04 BB06 BB08 BC01 4J002 BB121 BB141 BB151 BB203 BB213 BG062 BN031 BN033 BN053 BP021 BP031 GG02

Claims (2)

[Claims] 1. A polypropylene resin composition comprising the following components (A), (B) and (C). (A) 100 parts by weight of a crystalline propylene polymer (B) Average particle size having the following characteristics is 0.3 to 10 μm
0.05 to 5 parts by weight of organic fine particles of (1) Strength of 10 kgf when the particles are deformed by 10%
/ Mm ² or less. (2) It has a surface polarity of 45 dyne / mm or more. (3) The variation coefficient of the particle diameter calculated from the following equation is 30% or less. Coefficient of variation of particle size (%) = standard deviation of particle size (μm) / average particle size (μm) × 100 (C) The acid value specified by JIS K0070 is 1.0 to 1.0.
100mgKOH / g acid-modified polyolefin resin
0.01 to 1 part by weight 2. A stretched polypropylene resin film obtained by stretching a film comprising the polypropylene resin composition according to claim 1 in at least one direction.