JP2010024428A - Polypropylene film for packaging - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polypropylene film for packaging having high transparency and gloss and suppressed odor. <P>SOLUTION: The polypropylene film for packaging includes a propylene resin composition obtained by compounding 100 pts.wt. of a propylene polymer with 0.01-2.0 pts.wt. of a clarifying nucleation agent (A) expressed by chemical structural formula (1), and has a glossiness of ≥135% and a haze value of ≤3% in the form of a film having a thickness of 100 μm. In the formula, n is an integer of 0-2; R<SP>1</SP>to R<SP>5</SP>may be the same as or different from each other and are each a hydrogen atom, a 1-20C alkyl group or the like; and R<SP>6</SP>is a 1-20C alkyl group. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a polypropylene packaging film with high transparency and high gloss and improved odor.

In recent years, the required performance of polypropylene-based packaging films has been increasing, and there is a strong demand for films having excellent transparency and glossy optical properties. If the contents do not look clear, the product value is inferior, and high transparency is desired because it is not preferred, and high optical properties are required rather than giving the product a high-class image by having high gloss. However, the existing technology has not yet achieved sufficiently high optical properties, and there has been a problem that the odor is remarkably lowered in order to obtain high optical properties. Particularly for food packaging applications, the problem of odor is large, and a lower odor polypropylene film is strongly demanded.

  As a method for producing a polypropylene packaging film, there are a casting method, an inflation method, a stretching method, and the like, which are appropriately and selectively used according to the packaging form and the required performance. However, when used in transparent applications, it has been difficult to achieve sufficient optical performance with only a propylene-based polymer.

  For this reason, various attempts have been made not only to improve propylene polymers, but also to improve optical properties by utilizing transparent nucleating agents for propylene polymers. As the clearing nucleating agent, an organophosphate nucleating agent (Patent Document 1), a dimethylbenzylidene sorbitol nucleating agent (Patent Document 2), etc. are most commonly used.

However, even if these existing clearing nucleating agents are used, the range of improvement in optical properties is not always sufficient, and even if optical properties are improved, a new problem of odor occurs, which is preferred for food applications. However, it has been strongly desired to improve to a balanced packaging film having low odor and excellent optical properties by a new method.
Japanese Patent Laid-Open No. 5-140466 JP-A-53-117044

  An object of the present invention is to provide a polypropylene packaging film having excellent transparency and glossiness and improved odor.

As a result of intensive studies to solve the above problems, the present inventors have used polypropylene having a specific clarification nucleating agent for a propylene-based polymer, whereby polypropylene having excellent transparency and gloss and improved odor. It discovered that it could become a film for system packaging, and came to complete this invention.
That is, the features of the present invention are enumerated sequentially as follows.
(1) A propylene resin composition in which 0.01 to 2.0 parts by weight of a nucleating agent (A) represented by the following chemical structural formula (1) is blended with 100 parts by weight of a propylene polymer. A polypropylene packaging film characterized by having a gloss measured by ASTM D2457-1970 of not less than 135% and a HAZE of 3% or less in a film having a thickness of 100 μm measured in accordance with JIS K7136.
[Wherein n is an integer of 0 to 2 and R ^{1 to} R ⁵ are the same or different and each is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, an alkenyl group, an alkoxy group, a carbonyl group, a halogen atom. Group and a phenyl group, and R ⁶ is an alkyl group having 1 to 20 carbon atoms. ]
(2) The polypropylene-based packaging film according to (1), wherein the clearing nucleating agent (A) is a clearing nucleating agent (A1) represented by the following chemical structural formula (1 ′): .

[However, n is an integer of 0 to 2, R ¹ , R ² , R ⁴ and R ⁵ are each a hydrogen atom, and R ³ and R ⁶ are the same or different and each has 1 carbon number. ˜20 alkyl groups. ]
(3) The polypropylene packaging film according to (1) and (2) above, wherein the thickness is 5 to 300 μm.

  The propylene-based resin composition of the present invention is a polypropylene-based resin composition in which a novel clearing nucleating agent represented by the chemical structural formula (1) is blended in an amount of 0.01 parts by weight or more, more preferably 0.2 parts by weight or more. By using such a new nucleating agent, it is possible to satisfy the transparency and glossiness that could not be realized with conventional propylene resin compositions and to have a low odor. A polypropylene-based packaging film characterized by having a HAZE of 3% or less and a gloss of 135% or more is provided. In addition, by improving the morphology of the polypropylene polymer with a nucleating agent, the impact strength is not lowered, in particular, the rigidity is increased, not only the transparency, but also the heat deformation temperature is increased, and the bending is further improved. Various physical properties, such as increasing the elastic modulus, can be improved, so that the film can be thinned, thereby achieving the problem of weight reduction.

  In the present invention, 100 parts by weight of a propylene polymer having a melt flow rate based on JIS K7210 (230 ° C., 2.16 kg load) of 1 to 50 g / 10 minutes is represented by the general formula (1). A resin composition containing 0.01 parts by weight or more, more preferably 0.2 parts by weight or more of the nucleating agent (A), or a polypropylene packaging film obtained by molding the resin composition by various methods. It is. Hereinafter, the component which comprises a propylene resin composition, the manufacturing method of a resin composition, and the polypropylene-type packaging film are demonstrated in detail.

[1] Propylene polymer The propylene polymer used for the polypropylene packaging film of the present invention is a propylene homopolymer or a propylene copolymer (random copolymer, block copolymer). Or a mixture thereof. In the case of a copolymer, it is common to use one or more selected from the group consisting of α-olefins other than ethylene or propylene as a comonomer, but is not limited thereto. .

Moreover, the propylene-type polymer whose melt flow rate based on JISK7210 (230 degreeC, 2.16kg load) is 1-50 g / 10min is preferable. If the melt flow rate is significantly lower than 1 g / 10 min, the extrusion load at the time of extrusion molding increases, the surface smoothness may be impaired, and the appearance of the molded product may deteriorate, conversely, 50 g / 10 min. If it exceeds significantly, the uniform dispersibility of the clearing nucleating agent in the propylene-based polymer may be deteriorated, and the transparency may be hardly exhibited.
One of the features of the propylene-based polymer of the present invention is that the melt flow rate (MFR) is 1 to 50 g / 10 min. Within this range, the propylene-based polymer of the present invention has significant processing advantages. It is possible to explain not only the characteristics but also the significance of various properties, and it is advantageous in achieving the object of the present invention. Further, if the propylene polymer is described in detail, the relationship between the MFR and the average molecular weight (Mw) can be described with reference to the molecular weight that is approximately in a linear relationship (logarithmic logarithm). When a preferable example of Mw / Mn (weight average molecular weight (Mw), number average molecular weight (Mn)), which is one of the indicators of molecular weight distribution, is shown, the weight average molecular weight (Mw) measured by GPC is 5000 to 400000. In the example of the specification having a number average molecular weight of about 3000 to 300,000, the Ziegler catalyst polypropylene polymer has Mw / Mn of about 3 to 12, and the metallocene catalyst polypropylene has about 2 or about 2.4. There are many things of about 2-6. The narrow molecular weight distribution tends to be a hindrance to molding because the melt tension is small, but on the other hand, the MFR becomes high, which can be processed relatively stably. It is characterized by high heat resistance and high heat distortion temperature. Further, it is advantageous in terms of transparency, gloss, and strength. More importantly, the narrow molecular weight distribution means that the amount of solvent extraction is small, that is, so-called attack propylene, or low low molecular weight by-products. It can be predicted that it will act relatively advantageously on the action of the nucleating agent of the polypropylene polymer packaging film.

Odors such as aldehyde odors from melt degradation products during molding processes, from volatiles, or from certain nucleating agent degradation products in the case of propylene-based polymers free of low molecular weight by-products The fact that Mw / Mn increases to 4, 6, 8, and 10 indicates that the difference in refractive index between the crystalline part and the amorphous part tends to occur. In order to maximize the function of the nucleating agent, technical consideration from the polypropylene polymer side is to make Mw / Mn as small as possible, that is, for example, Mw / Since it is expected that Mw / Mn is 4 rather than Mn is 12, if the polymerization method in the production stage of the polypropylene polymer is taken into consideration, the metallocene-catalyzed polymerization is transparent. , Odor, gloss In the heat deformation temperature of the packaging film, it is expected to be somewhat advantageous.
In this sense, the propylene-based polymer of the present invention preferably has a Mw / Mn of 2 to 10, preferably 2 to 8, more preferably about 2 to 4. A material having such a range is excellent in transparency, and has an advantageous effect on enhancing the function of the nucleating agent.

  The catalyst used for obtaining the propylene-based polymer used in the present invention is not particularly limited, and a known catalyst can be used. For example, a so-called Ziegler-Natta catalyst or a metallocene catalyst (for example, described in JP-A-5-295022), which is a combination of a titanium compound and organoaluminum, can be used. From the viewpoint of suppression, it is preferable to use a metallocene catalyst from the viewpoint of being extremely effective.

  The polymerization process used to obtain the propylene-based polymer used in the present invention is not particularly limited, and a known polymerization process can be used. For example, a slurry polymerization method, a bulk polymerization method, a gas phase polymerization method and the like can be used. Moreover, it can also superpose | polymerize by performing multistage polymerization combining the 1 type (s) or 2 or more types of these polymerization methods. Further, it can also be produced by mechanically melting and kneading two or more kinds of propylene polymers.

[2] Transparent nucleating agent The transparent nucleating agent used in the present invention is a transparent nucleating agent (A) represented by the following chemical structural formula (1):

[Wherein n is an integer of 0 to 2 and R ^{1 to} R ⁵ are the same or different and each is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, an alkenyl group, an alkoxy group, a carbonyl group, a halogen atom. Group and a phenyl group, and R ⁶ is an alkyl group having 1 to 20 carbon atoms. ]

Preferably, the chemical structural formula (1) [where n is an integer of 0 to 2, R ¹ , R ² , R ⁴ and R ⁵ are each a hydrogen atom, and R ³ and R ⁶ are They are the same or different and each is an alkyl group having 1 to 20 carbon atoms. ] The clearing nucleating agent (A) shown by these.
More preferably, the clarifying agent (A) represented by the chemical structural formula (1) is specifically a clearing nucleating agent (A1) represented by the following general formula (1 ′).

[N is an integer of 0 to 2, R ¹ , R ² , R ⁴ and R ⁵ are each a hydrogen atom, and R ³ is —CH ₃ , —CH ₂ CH ₃ , —CH _{2 CH 2 CH 3, -CH 2 CH} 2 CH 2 CH 3, -CH 2 CH = CH 2, -CH (CH 3) CH = CH 2, -CH 2 CH-X 1 -CH 2 -X 2, -CH ₂ CH—X ³ —CH ₂ CH ₃ , —CH ₂ CH—X ⁴ —CH ₂ OH or —CH ₂ OH—CH (OH) —CH ₂ OH (provided that X ^{1 to} X ⁴ are each independently And R ⁶ is an alkyl group having 1 to 20 carbon atoms. ]

The clearing nucleating agent (A) used in the present invention gives the resulting polypropylene-based packaging film very excellent transparency that is impossible to achieve with conventional clearing nucleating agents.
The blending amount of the clearing nucleating agent (A) used in the polypropylene packaging film of the present invention is 0.01 parts by weight or more with respect to 100 parts by weight of the propylene polymer. If it is less than 0.01 part by weight, it is difficult to obtain a sufficient effect. 0.2 parts by weight or more is more preferable. If the amount exceeds 2.0 parts by weight, the nucleating agent may be aggregated and the transparency may be lowered. As a manufacturing method of the clearing nucleating agent (A) used for this invention, the method as described in WO2005 / 111134 etc. can be mentioned. Commercially available products can also be easily obtained, for example, Mirad NX8000 (manufactured by Milliken & Company).

  Moreover, in the polypropylene-type packaging film of the present invention, at least one kind of other nucleating agent may be blended in addition to the clearing nucleating agent (A). Thereby, transparency, glossiness, etc. can further be improved. The nucleating agent used here is not particularly limited, and known nucleating agents can be used. For example, known clearing nucleating agents such as sorbitol-based clearing nucleating agents, organic phosphate-based clearing nucleating agents, aromatic phosphate esters, and talc can be added within a range that does not significantly impair the effects of the present invention.

[3] Other additives In the present invention, in addition to the propylene polymer and the clearing nucleating agent (A), various antioxidants, neutralizers, and the like used as stabilizers for the propylene polymer, Additives such as a lubricant, an ultraviolet absorber and a light stabilizer can be blended.

  Specifically, as the antioxidant, bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol-di-phosphite, di-stearyl-pentaerythritol-di-phosphite, bis ( 2,4-di-t-butylphenyl) pentaerythritol-diphosphite, tris (2,4-di-t-butylphenyl) phosphite, tetrakis (2,4-di-t-butylphenyl) -4 Phosphorous antioxidants such as 4,4'-biphenylene-diphosphonite, tetrakis (2,4-di-t-butyl-5-methylphenyl) -4,4'-biphenylene-diphosphonite, 2,6-di-t-butyl-p-cresol, tetrakis [methylene (3,5-di-t-butyl-4-hydroxyhydrocinnamate)] methane, 1 3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, tris (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate Phenolic antioxidants such as di-stearyl-ββ'-thio-di-propionate, di-myristyl-ββ'-thio-di-propionate, di-lauryl-ββ'-thio-di-propionate An antioxidant etc. are mentioned.

Specific examples of the neutralizing agent include metal fatty acid salts such as calcium stearate, zinc stearate and magnesium stearate, hydrotalcite (trade name: magnesium represented by the following general formula (2) of Kyowa Chemical Industry Co., Ltd.) Aluminum complex hydroxide salt), Mizukarak (lithium aluminum composite hydroxide salt represented by the following general formula (3)), and the like.
Mg _1-x Al _x (OH) ₂ (CO ₃ ) _{x / 2} · mH ₂ O (2)
[Wherein x is 0 <x ≦ 0.5, and m is a number of 3 or less. ]

[Al ₂ Li (OH) ₆ ] _n X · mH ₂ O (3)
[Wherein, X is an inorganic or organic anion, n is the valence of the anion (X), and m is 3 or less. ]

  Specific examples of the lubricant include known lubricants, and examples thereof include fatty acid amides such as oleic acid amide, stearic acid amide, erucic acid amide, and behenic acid amide, butyl stearate, and silicone oil.

  Examples of the ultraviolet absorber include 2-hydroxy-4-n-octoxybenzophenone, 2- (2′-hydroxy-3 ′, 5′-di-t-butylphenyl) -5-chlorobenzotriazole, 2- (2 And ultraviolet absorbers such as' -hydroxy-3'-t-butyl-5'-methylphenyl) -5-chlorobenzotriazole.

  Examples of the light stabilizer include n-hexadecyl-3,5-di-t-butyl-4-hydroxybenzoate, 2,4-di-t-butylphenyl-3 ′, 5′-di-t-butyl-4 ′. -Hydroxybenzoate, dimethyl-2-succinate-2- (4-hydroxy-2,2,6,6-tetramethyl-1-piperidyl) ethanol condensate, poly {[6-[(1,1,3,3-tetra Methylbutyl) amino] -1,3,5-triazine-2,4diyl] [(2,2,6,6-tetramethyl-4-piperidyl) imino] hexamethylene [(2,2,6,6- Tetramethyl-4-piperidyl) imino]}, N, N′-bis (3-aminopropyl) ethylenediamine-2,4-bis [N-butyl-N- (1,2,2,6,6-pentamethyl-) 4-piperidyl) amino] -6 It can be given a light stabilizer such as Rollo triazine condensate.

  Further, an amine-based antioxidant represented by the following general formula (4) or the following general formula (5), 5,7-di-t-butyl-3- (3,4-di-methyl-phenyl) -3H -Lactone type antioxidants, such as benzofuran-2-one, and vitamin E type antioxidants, such as following General formula (6), can be mentioned.

[Wherein R ¹ and R ² are alkyl groups having 14 to 22 carbon atoms]

  In addition, an antistatic agent, a dispersant such as a fatty acid metal salt, a high-density polyethylene, a low-density polyethylene, a linear low-density polyethylene, and an olefin-based elastomer can be blended within a range that does not impair the object of the present invention. . When linear low density polyethylene and an olefin elastomer are blended, those polymerized with a metallocene catalyst are preferred from the viewpoint of transparency.

[4] Propylene resin composition production method The propylene resin composition used for the polypropylene packaging film of the present invention comprises a propylene polymer, a clearing nucleating agent (A) and other additives used as necessary. Is mixed into a Henschel mixer, super mixer, ribbon blender, etc., and then melt kneaded at a temperature range of 180 to 280 ° C. with a normal single screw extruder, twin screw extruder, Banbury mixer, plastic bender, roll, etc. Can be obtained.

[5] Molding method The polypropylene packaging film of the present invention is characterized in that the gloss is 135% or more and the HAZE is 3% or less, and if the gloss is less than 135, the sense of quality is impaired and the commercial value is increased. However, if HAZE exceeds 3%, the transparency is deteriorated and the contents cannot be clearly confirmed, and the commercial value is inferior. Preferably, the gloss is 140% or more and HAZE is 2% or less. In order to produce such a film, it can be obtained by molding by a known casting method, inflation method, stretching method or the like. Of these, the cast method and the water-cooled inflation method are preferable.

The casting method is a method for producing an extrusion-molded body such as a sheet or a film (unstretched film). The resin composition melt-kneaded by an extruder is extruded from a T-die and passed through a roll through which a coolant such as water passes. Since the film is cooled by being brought into contact with the film and generally has good transparency and glossiness and can be produced with a good thickness accuracy, it is a preferable production method for the film.
The nucleating agent of the present invention not only simply prevents the development of spherulites by refining the crystal of the polypropylene polymer, but also homogenizes and refines the amorphous part having a relatively low melting point. Raising the crystallization temperature of the polymer results in increasing the strength of the waist as a packaging film.

  In the polypropylene-based packaging film of the present invention, when it is molded and used as a single layer film, the thickness is usually 5 to 500 μm, preferably 10 to 200 μm. Even if the thickness is less than 5 μm or more than 200 μm, processing becomes difficult.

The polypropylene packaging film of the present invention may be an inflation method. The inflation method is a method for producing a film by melting it with an extruder with an annular die, extruding it into a tube shape, and cooling it with water cooling and air cooling. The thickness of the film is usually preferably 10 to 150 μm.

  The polypropylene packaging film of the present invention may be in the form of a stretched film, in which case the stretched film is produced by stretching the sheet or film obtained as described above with a known stretching device. Can do. Examples of these stretching apparatuses include a tenter method, a simultaneous biaxial stretching method, and a uniaxial stretching method. The stretch ratio of the stretched film is desirably 10 to 70 times in the case of a biaxially stretched film, and desirably 2 to 10 times in the case of a uniaxially stretched film. Moreover, it is desirable that the thickness of the stretched film is usually 5 to 200 μm.

  The polypropylene-based packaging film of the present invention has a very high commercial value as a packaging material that has no whiteness, has a clear transparency, and has an excellent gloss and a high-quality odor and improved odor. Although it does not specifically limit as a use, It uses suitably for packaging uses, such as a foodstuff, medical treatment, stationery, and miscellaneous goods.

From the viewpoint of the transparency, high gloss, and low odor properties of the polypropylene packaging film of the present invention, the significance of the packaging film in a specific application will be described in more detail. The packaging film is required to have characteristics that can be adapted to diversification of packaging forms, taking advantage of its characteristics. For example, in addition to general packaging applications, the present invention can also be used in the field of application forms in which many packaging films are recently used.
(1) Wrapped or stretch wrapping: It is a normal form of use for tightly wrapping with a molded unstretched or stretched wrapping film, which can be expressed as wrap or stretch wrapping.
(2) Shrink wrapping; a form of wrapping utilizing the heat-shrinkable nature of the wrapping film, which is expressed as shrink wrapping.
(3) Vacuum packaging: This is a technique in which the contents are covered with a film, and the intervening air is sucked by a vacuum forming machine and closely packed.
(4) Retort packaging; a packaging form compatible with retort processing.
(5) Laminated film: Composite film form laminated with other polypropylene resin for the polypropylene packaging film of the present invention or polypropylene or polyethylene other than the polypropylene packaging film of the present invention.
Thus, the polypropylene-based packaging film of the present invention includes embodiments that can be used in various packaging forms and packaging methods, and diversifies such packaging forms as the polypropylene-based packaging film of the present invention. It has applicable characteristics and performance.

General functions required for the packaging film include the following.
(I) It has a quality function that appropriately expresses the appearance, state, freshness, and aesthetic appearance of the contents as well as the protection of the contents during transportation, storage, store display, etc. of the contents. The polypropylene-based packaging film of the present invention has a HAZE of 3% or less and a gloss of 135% or more, which satisfies the above requirements.
(Ii) Increase product value. Usually, a polypropylene packaging film has a HAZE of about 3 to 10%, and has a performance of 3% or less, preferably 2% or less, more preferably 1.0% or less of the present invention. It can be evaluated that it is excellent. Similarly, the gloss may be as high as 100% or more, and in some cases, 120 or more. Preferably, the gloss is 135% or more and 150% or more is very good. The characteristics of these packaging films are extremely useful in enhancing the commercial value of the contents when packaging fresh food, fashionable fibers, clothing, and other products that require introspection.
It can be said that the polypropylene-based packaging film of the present invention has sufficient properties, characteristics, functions, and operational effects that satisfy the requirements (i) to (ii).

Regarding other usage forms, for example, in the applications (1) to (5) described above, the polypropylene-based packaging film of the present invention has significance, and its high transparency and glossiness and its low From the viewpoint of odor, it is extremely useful for increasing the commercial value of the contents as shown in (i) to (ii).
As described above, the polypropylene packaging film comprising the propylene resin composition of the present invention not only plays a role of increasing the commercial value in any packaging form, but also maintains the working environment and improves moldability in molding. , With multifaceted significance.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited at all by these description. In each Example and Comparative Example, the physical properties used were measured by the following methods, and the following were used as propylene polymers, clearing nucleating agents and other additives (neutralizing agents, lubricants, etc.). did.

1. Test Method (1) (i) Ethylene Concentration: Ethylene content in the random copolymer by infrared spectroscopy using a characteristic absorber of 733 cm ⁻¹ with an ethylene / propylene random copolymer whose composition was verified by ¹³ C-NMR as a reference substance Was measured. The pellets were formed into a film having a thickness of about 500 microns by press molding.
(Ii) Butene concentration: The ethylene content in the random copolymer was measured by infrared spectroscopy using a characteristic absorber of 767 cm ⁻¹ using an ethylene / propylene random copolymer whose composition was verified by ¹³ C-NMR as a reference substance. The pellets were formed into a film having a thickness of about 500 microns by press molding.
(2) MFR: Measured according to JIS K7120-1999, 230 ° C. 2.16 kg load.

(3) Haze value: Measured according to JIS K7136 using a molded film. The film thickness was measured by producing a film having a thickness of 100 μm when a T-die molding machine was used. When an air-cooled inflation molding machine was used, a film having a thickness of 30 μm was produced and measured.

(4) Gloss: Measured according to ASTM D2457-1970 using a molded film.
(5) Odor
Odor evaluation: A grading sensory evaluation was performed according to JIS Z9080. Sensory evaluation of odor bag air stored in a 6L polyethylene terephthalate odor bag with 100g of molded film and odorless air obtained through activated carbon stored at room temperature 23 ° C and humidity 50% for 7 days was performed by 6 panelists. . (5: very strong smell, 4: strong smell, 3: smell, 2: weak smell, 1: very weak smell, 0: no smell)
(6) Bleedability: Evaluation was performed by the difference between the haze value measured after the molded film was stored in a 40 ° C. gear oven for 14 days and the measured molded film after the surface was washed with ethanol. (The larger the value, the greater the amount of bleed. A better index for long-term storage. The smaller the value, the better the bleed.)

2. Propylene polymer, clearing nucleating agent and other additives (1) Propylene polymer (i) Ethylene / propylene random copolymer (RPP): metallocene catalyst, ethylene concentration 1.9% by weight, MFR 7 g / 10 min (Ii) Ethylene / propylene / butene-1 random copolymer (RPP): Ziegler-Natta catalyst, ethylene concentration 3.1 wt%, butene concentration 1.3 wt%, MFR 8 g / 10 min

(2) Clearing nucleating agent (i) Mirad NX8000 (manufactured by Milliken & Company): Clearing nucleating agent (A) equivalent product: Compound of chemical structural formula represented by the following general formula (7)

(Ii) ADK STAB NA11 (manufactured by ADEKA Corporation): Organophosphate metal salt compound-based transparent nucleating agent: Clearing nucleating agent not corresponding to transparent nucleating agent (A) (iii) Gelol MD (New Nippon Rika ( Co., Ltd.): Dimethylbenzylidenesorbitol nucleating agent: Clearing nucleating agent not equivalent to nucleating agent (A)

(3) Antioxidant (i) Hindered phenol antioxidant: Irganox 1010 (IR1010; manufactured by Ciba). Tetrakis [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxylphenyl) propionate] methane.
(Ii) Phosphorus antioxidant: Irgaphos 168 (IF168; manufactured by Ciba). Tris (2,4-di-tert-butylphenol) phosphite.

(4) Neutralizing agent (i) Calcium stearate (CAST; manufactured by NOF Corporation)

(5) Lubricant (i) Fatty acid amide: erucic acid amide, behenic acid amide

[Example]
EXAMPLES Next, although an Example and a comparative example are given and this invention is demonstrated still in detail, this invention is not limited to a following example, unless the summary is exceeded.
Manufacture of polypropylene resin

[Production Example 1] Production of propylene random copolymer (PP-1) a. A racemic form of dimethylsilylenebis [1- {2-methyl-4- (4-chlorophenyl) -4H-azurenyl}] zirconium dichloride is synthesized based on the description in Example 1 of JP-A-2002-20430. did.

B. Chemical treatment of clay mineral In a solution obtained by mixing 218.1 g of sulfuric acid (96%) and 130.4 g of magnesium sulfate with 909 ml of demineralized water, 200.03 g of commercially available montmorillonite (Kunimine Kogyo, Kunipia F) is dispersed at 100 ° C. Stir for 2 hours. This water slurry of montmorillonite was adjusted to a solid content concentration of 12%, and spray granulation was performed with a spray dryer to obtain particles. Thereafter, the particles were dried under reduced pressure at 200 ° C. for 2 hours.

C. Preparation of Solid Catalyst Component After the inside of a stirring autoclave having an internal volume of 1 liter was sufficiently substituted with propylene, 230 ml of dehydrated and deoxygenated heptane was introduced, and the system temperature was maintained at 40 ° C. 10 g of the above chemically treated clay slurried with toluene was added thereto. Furthermore, in another container, 0.15 mmol of the above metallocene compound and 1.5 mmol of triisobutylaluminum mixed under toluene were added. Here, propylene was introduced at a rate of 10 g / hour for 120 minutes, and then polymerization was continued for 120 minutes. Further, the solvent was removed and dried under nitrogen to obtain a solid catalyst component. This solid catalyst component contained 1.9 g of polypropylene per 1 g of the solid component.

D. Propylene / Ethylene Copolymerization After the inside of a stirring autoclave having an internal volume of 200 l was sufficiently substituted with propylene, 45 kg of sufficiently dehydrated liquefied propylene was introduced. To this, 500 ml (0.12 mol) of a triisobutylaluminum / n-heptane solution, 1.22 kg of ethylene, and 6 L of hydrogen (as a standard state volume) were added, and the internal temperature was maintained at 30 ° C. Next, 2.4 g of the solid catalyst component was injected with argon to initiate polymerization, and the temperature was raised to 70 ° C. over 30 minutes, and the temperature was maintained for 1 hour. Here, 100 ml of ethanol was added to stop the reaction. The residual gas was purged to obtain 18 kg of a propylene / ethylene random copolymer (PP-1).
The polymer had an MFR of 7 g / 10 min, a melting point of 135 ° C., and an ethylene content of 2.1% by weight.

[Production Example 2] Production of propylene-based butene random copolymer (PP-2) Based on the description in Example 12 of JP-A-56-143207, 3.11 kg of a propylene / ethylene / butene random copolymer (PP-2) was obtained.
The polymer had an MFR of 8 g / 10 min, a melting point of 138 ° C., an ethylene concentration of 3.1 wt%, and a butene concentration of 1.3 wt%.

(Examples 1-5, Comparative Examples 1-6)
IR1010 as an antioxidant, 0.05 part by weight of IF168 and 0.05 part by weight of calcium stearate as a neutralizer in the resin and the clearing additive in the blending ratios shown in Tables 1 and 2 Then, 0.04 parts by weight of erucic acid amide as a lubricant and 0.08 parts by weight of behenic acid amide were dry blended with a super mixer, and then melt-kneaded using a 50 mm diameter extruder. Extruded pellets from the die at a die outlet temperature of 200 ° C. The obtained pellets are rapidly cooled with a T-die molding machine (casting method) with a cooling roll having a resin temperature of 230 ° C., an air knife, and a surface temperature of 30 ° C., and wound into a film having a thickness of 100 μm and a width of 30 cm. A test film was prepared. Using the obtained film, the physical properties were measured. The evaluation results are shown in Tables 1 and 2.

Examples 1 to 3 were obtained by blending the nucleating agent (A) in the range of 0.1 to 0.4 parts by weight with respect to the propylene / ethylene random copolymer obtained using the metallocene catalyst. It is a packaging film. The evaluation results are shown in Table 1. It can be seen that the polypropylene-based packaging film of the present invention is very excellent in transparency and gloss, and the odor is extremely improved.
On the other hand, Comparative Example 1 is a packaging film that does not contain the clearing nucleating agent (A). The evaluation results are shown in Table 1. If the clearing nucleating agent (A) is not blended, the transparency and gloss will be poor.
Comparative Examples 2 and 3 are packaging films obtained by blending 0.2 parts by weight of typical clearing nucleating agents conventionally used outside the scope of the present invention. The evaluation results are shown in Table 1. Although the comparative example 2 is excellent in transparency and glossiness, generation | occurrence | production of an odor is seen. It can be seen that Comparative Example 3 is excellent in terms of low odor, but is inferior in transparency and gloss.

Examples 4 and 5 were obtained by blending the nucleating agent (A) in the range of 0.2 to 0.4 parts by weight with respect to the propylene / ethylene random copolymer obtained using the Ziegler-Natta catalyst. Film for packaging. The evaluation results are shown in Table 2. It can be seen that the polypropylene-based packaging film of the present invention is very excellent in transparency and gloss, and the odor is extremely improved.
In contrast, Comparative Example 4 is a packaging film that does not contain the clearing nucleating agent (A). The evaluation results are shown in Table 2. If the clearing nucleating agent (A) is not blended, the transparency and gloss will be poor.
Comparative Examples 5 and 6 are packaging films obtained by blending 0.2 parts by weight of a conventionally used typical nucleating agent outside the scope of the present invention. The evaluation results are shown in Table 2. Comparative Example 5 is excellent in transparency and gloss, but generation of odor is observed. It can be seen that Comparative Example 6 is excellent in terms of low odor, but is inferior in transparency and gloss.

Example which is a film for packaging obtained by blending clear nucleating agent (A) in the range of 0.2 to 0.4 parts by weight to propylene / ethylene random copolymer obtained using metallocene catalyst The bleed properties of Nos. 2 and 3 are obtained by blending the nucleating agent (A) in the range of 0.2 to 0.4 parts by weight with respect to the propylene / ethylene random copolymer obtained using a Ziegler-Natta catalyst. It turns out that it is excellent with respect to the bleeding property of Example 4 and 5 which is the obtained packaging film. Depending on the use environment of the packaging film of the present invention, it may be understood that a superior bleed property may be required, so that a propylene polymer obtained using a metallocene catalyst is more dominant.

(Comparative Example 7, Comparative Example 8)
As an antioxidant, 0.05 part by weight of IR1010, 0.05 part by weight of IF168, 0.05 part by weight of calcium stearate and 0.05 part by weight of calcium stearate as a lubricant are added to the resin and the clearing additive in the blending ratio shown in Table 3. 0.04 part by weight of erucic acid amide and 0.08 part by weight of behenic acid amide were dry-blended with a super mixer and then melt-kneaded using a 50 mm diameter extruder. Extruded pellets from the die at a die outlet temperature of 200 ° C. The pellet obtained was melt-extruded at a resin temperature of 180 ° C. from an annular die having a diameter of 200 mm and a lip of 3 mm mounted on an extruder having a diameter of 50 mm, and air-cooled inflation molding was performed at a blow ratio = 2 and a take-off speed of 16 m / min. A test film having a thickness of 30 μm was prepared. Using the obtained film, the physical properties were measured. The evaluation results are shown in Table 3. As is clear from Table 3, it can be seen that Comparative Example 7 is very excellent in transparency and gloss as compared with Comparative Example 8 in which the clearing nucleating agent (A) is not blended. However, transparency and gloss are not in the casting method, and it can be seen that the casting method is preferable as the molding method.

The polypropylene packaging film of the present invention is very excellent in transparency and gloss and has improved odor, and high transparency and low odor are particularly preferred for medical use from the viewpoint of safe management. Further, by using this film having transparency, gloss and low odor for packaging applications, it is possible to give a high-class feeling and increase the value of products such as foods, stationery and miscellaneous goods.

Claims (3)

ASTM obtained using a propylene-based resin composition in which 0.01 to 2.0 parts by weight of a clearing nucleating agent (A) represented by the following chemical structural formula (1) is blended with 100 parts by weight of a propylene-based polymer. A polypropylene-based packaging film having a gloss measured by D2457-1970 of 135% or more and a thickness HAZE measured by JIS K7136 of 3% or less.

[Wherein n is an integer of 0 to 2 and R ^{1 to} R ⁵ are the same or different and each is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, an alkenyl group, an alkoxy group, a carbonyl group, a halogen atom. Group and a phenyl group, and R ⁶ is an alkyl group having 1 to 20 carbon atoms. ]
2. The polypropylene packaging film according to claim 1, wherein the clearing nucleating agent (A) is a clearing nucleating agent (A1) represented by the following chemical structural formula (1 ′).

[However, n is an integer of 0 to 2, R ¹ , R ² , R ⁴ and R ⁵ are each a hydrogen atom, and R ³ and R ⁶ are the same or different and each has 1 carbon number. ˜20 alkyl groups. ]
Thickness is 5-300 micrometers, The polypropylene-type packaging film of Claim 1 and 2 characterized by the above-mentioned.