JP4923330B2 - Cap liner material composition and cap - Google Patents

Description

【発明の効果】
本発明のキャップライナー材用組成物は、従来公知のキャップライナー材用組成物には無い、耐熱性と柔軟性及びキャップライナー成形性を併せ持ち、高温殺菌処理をした後であっても、ライナー性能を保持し有用である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a resin composition that has high heat resistance, is rich in flexibility, and is excellent in cap liner moldability (particularly in-shell moldability). Specifically, the cap liner material composition is made flexible and heat resistant, so that when used as a cap liner for food (beverage) packaging containers, the contents (packaging containers) are sterilized at higher temperatures. Heat treatment is possible.
[0002]
Due to such characteristics, the composition of the present invention can be processed at high temperature in the sterilization process of food (beverage) contents (packaging container) due to the superior heat resistance of the cap liner, and the processing time can be shortened. It is effective because it has the effect of preventing the flavor of the contents from being influenced by the temporal heat history.
[0003]
In addition, recently, retort sterilization (100 to 130 ° C. for 1 to 30 minutes heat treatment) may be required for some of the diversified foods, which can be used and is effective.
[0004]
[Prior art]
Generally, as a composition used for a cap liner, a composition obtained by adding a hydrogenated styrene-conjugated diene block copolymer rubber, liquid paraffin, or the like to polyolefin (Japanese Patent Publication No. 6-88608) or a simple polyethylene-based composition Resin was used suitably.
[0005]
However, these compositions have low heat resistance, and the heat treatment temperature in the sterilization process of food (beverage) contents (packaging container) is about 95 ° C. even at a high temperature, so that a sufficient sterilization effect is exhibited. The sterilization time was extended. However, there have been concerns about the content being altered and the flavor being changed due to a long thermal history.
[0006]
As described above, the currently used cap liner material composition has the above-mentioned problem of low heat resistance, and can be sterilized at a higher temperature, and its composition. There is a need for a cap having a cap liner comprising:
[0007]
[Problems to be solved by the invention]
An object of the present invention is to provide a cap liner material composition having excellent heat resistance and excellent flexibility and cap liner moldability, and a cap having a cap liner made of the composition.
[0008]
[Means for Solving the Problems]
Therefore, as a result of intensive studies by the present inventors, a propylene-ethylene / α-olefin copolymer which is an elastomer component having a specific melt flow rate and a high melting point as a flexibility-imparting material and a propylene-based copolymer having a high crystallization temperature. It has been found that a composition for a cap liner material comprising a combination with a polymer has flexibility, cap liner moldability and heat resistance, and has completed the present invention.
That is, in the present invention, a propylene polymer (A) 30 to 90 having a melt flow rate (JIS K7210-76; 230 ° C.-2.16 kg load) of 0.1 to 100 g / 10 min and a crystallization temperature of 120 ° C. or higher. Polypropylene-ethylene / α-olefin copolymer (b) having a melt flow rate (JIS K7210-76; 230 ° C.-2.16 kg load) of 1 to 50 g / 10 min and a melting point of 140 ° C. or higher is 70 to 10% by weight. It is a composition for cap liner materials characterized by comprising.
[0009]
The propylene polymer (A) used in the present invention has a melt flow rate (JIS K7210-76; 230 ° C.-2.16 kg load) of 0.1 to 100 g / 10 min and a crystallization temperature of 120 ° C. or higher. is there.
[0010]
The propylene polymer (A) has a melt flow rate (JIS K7210-76; 230 ° C.-2.16 kg load, hereinafter referred to as MFR) of 0.1 to 100 g / 10 min, preferably 1 to 50 g / 10 min. is there. When the MFR is less than 0.1 g / 10 min, an extrusion load is excessively applied during molding of the cap liner, resulting in poor molding, and when it exceeds 100 g / 10 min, the heat resistance and impact resistance are poor.
[0011]
The propylene polymer (A) has a crystallization temperature of 120 ° C. or higher. When the crystallization temperature is less than 120 ° C., the heat resistance is poor.
[0012]
The crystallization temperature was measured using a scanning differential calorimeter (DSC) (Perkin Elmer, apparatus name “DSC-7”. The sample was melted at 230 ° C. for 5 minutes in the DSC furnace. Then, the temperature at the maximum peak position of the exothermic curve obtained by solidifying (crystallization) by lowering to 30 ° C. at a cooling rate of 10 ° C./min was measured as the crystallization temperature.
[0013]
The propylene polymer (A) can be obtained by a known production method, and can be produced by polymerization of propylene or copolymerization with a small amount (5 wt% or less) of an α-olefin.
[0014]
The crystallization temperature of the propylene polymer (a) is usually around 115 ° C., but the target crystallization temperature of 120 ° C. or more can be achieved by adding a nucleating agent or the like. Specific examples of the nucleating agent include phosphoric acid metal salts (Adeka Stub NA-11 manufactured by Asahi Denka), carboxylic acid metal salts (shell Al-PTBBA), and the like. can get.
[0015]
The polypropylene-ethylene / α-olefin copolymer (b) used in the present invention has an MFR of 1 to 50 g / 10 min and a melting point of 140 ° C. or higher.
The polypropylene-ethylene / α-olefin copolymer (b) has an MFR of 1 to 50 g / 10 min, and preferably 5 to 30 g / 10 min. When the MFR of the polypropylene-ethylene / α-olefin copolymer (b) is less than 1 g / 10 min, an extrusion load is excessively applied at the time of cap liner molding, resulting in poor molding, and when it exceeds 50 g / 10 min, the heat resistance and impact resistance are poor.
[0016]
The polypropylene-ethylene / α-olefin copolymer (b) has a melting point of 140 ° C. or higher. When the melting point of the polypropylene-ethylene / α-olefin copolymer (b) is less than 140 ° C., the heat resistance is poor.
[0017]
The melting point was measured using a scanning differential calorimeter (DSC) (manufactured by Perkin Elmer, apparatus name “DSC-7”. The sample was once heated in a DSC furnace to 230 ° C. and 30. After cooling to 0C and holding for 5 minutes, the temperature at the maximum peak position of the endothermic curve obtained by melting up to 230C at a heating rate of 10C / min was measured as the melting point.
[0018]
Here, as the α-olefin used in the polypropylene-ethylene / α-olefin copolymer (b), for example, propylene, 1-butene, 4-methyl-1-pentene, 3-methyl-1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1- Examples include octadecene, 1-nonadecene, and 1-eicosene, and one or more types may be copolymerized. Of these, propylene and 1-butene are generally used as α-olefins. Among them, 1-butene improves compatibility with the propylene-based polymer (A), and has material properties, particularly high tensile strength. Low compression set, high ESCR, large improvement effect, and effective cap liner performance.
[0019]
Polypropylene-ethylene / α-olefin copolymer (b) has a structure in which the ethylene / α-olefin copolymer component is finely dispersed in a matrix mainly composed of polypropylene. Catelloy (C200F, KS-359P, KS-357P, KS-084P, X500F, etc.) manufactured by Montel is available.
[0020]
Further, as the ethylene / α-olefin copolymer (b), one kind or two or more kinds of blends can be used.
[0021]
The composition for cap liner material of the present invention is 30 to 90% by weight, preferably 40 to 80% by weight of the propylene polymer (A), and 70 to 10% of ethylene / α-olefin copolymer (B). It is composed of wt%, preferably 60-20 wt%. When the propylene polymer (a) is less than 30% by weight, the heat resistance is poor, and when it exceeds 90% by weight, the rigidity is too high and the impact resistance is poor.
[0022]
The composition for a cap liner material of the present invention includes a thermoplastic resin, a heat stabilizer, a weather stabilizer, an anti-blocking agent, an antistatic agent, a slip agent, a surfactant, an antifogging agent, a droplet agent, if necessary. Inorganic or organic additives such as plasticizer, nucleating agent, pigment, dye, silica, titanium oxide, talc, mica, carbon, calcium carbonate, magnesium carbonate, metal stearate, wood powder, cork powder, cellulose powder, You may add a filler in the range which does not impair the objective of this invention.
[0023]
Among them, the slip agent is often necessary for adjusting the cap opening torque, and is generally suitably used. For example, higher fatty acid amide, higher fatty acid, glycerin fatty acid ester, sorbitan fatty acid ester, propylene glycol fatty acid ester, higher alcohol fatty acid ester, ethylene bis higher fatty acid amide, etc. are used, preferably higher fatty acid amide is used. , Caprylic acid amide, capric acid amide, lauric acid amide, myristic acid amide, palmitic acid amide, stearic acid amide, arachidic acid amide, behenic acid amide, oleic acid amide, erucic acid amide, linoleic acid amide, linolenic acid Amides are mentioned.
[0024]
The composition for a cap liner material of the present invention comprises the above-mentioned propylene-based polymer (i) and a polypropylene-ethylene / α-olefin copolymer (b) in various methods known within the above range, such as a Henschel mixer, V -After mixing with a blender, ribbon blender, tumbler blender, etc., melt kneading with a single screw extruder, twin screw extruder, kneader, Banbury mixer, etc., granulating or grinding, or dry blending without prior melt kneading Or a method using an auto feeder is used.
[0025]
In order to obtain a cap molded product, a cap having the cap liner material composition as a cap liner is obtained by an in-shell molding method.
[0026]
The cap liner material composition of the present invention is characterized in that a polypropylene-ethylene / α-olefin copolymer having a melt flow rate and a melting point limited to a specific range is added to a propylene-based polymer having a high crystallization temperature. The cap liner material composition is superior in cap liner moldability and has both high heat resistance and flexibility, which is not found in conventional cap liner material compositions.
[0027]
Caps provided with the cap liner comprising the composition for cap liner material of the present invention based on the above features are soft drinks, alcoholic beverages, coffee beverages, tea beverages, mineral water, dressings, grilled meat sauces, seasoning sauces, mayonnaise It can be used as a cap for packaging containers such as salad oil and sesame oil.
[0028]
【Example】
EXAMPLES Next, although an Example is given and this invention is demonstrated more concretely, this invention is not restrict | limited to these Examples, unless the summary is exceeded.
[0029]
The test measurement method used in the present invention is as follows.
[0030]
<Method for producing composition for cap liner material>
After blending each constituent raw material with a tumbler, kneading granulation is performed at 230 ° C. using a Tanabe Plastics Machine Co., Ltd. single screw extruder with L / D = 28 mm, 60 mmφ, and a composition for a cap liner material Got.
[0031]
<Liner formability evaluation>
Using a single screw extruder manufactured by Tanabe Plastics Machine Co., Ltd. with L / D = 25 mm and 40 mmφ, the composition for the cap liner material is melt-kneaded at a resin temperature of 230 ° C., a screw rotation speed of 100 rpm, and a discharge rate of 15 kg / h. One strand is taken out from a hole of 8 mmφ opened in the part. The strand coming out from the die head part is hot-cut with a rotary cutter so as to be 300 mg as it is. The hot-cut molten pellets are dropped onto a 28 mmφ polypropylene cap, cooled under pressure, and arranged into a cap liner shape. 1000 cap liners are molded and the success rate is measured. (Note that Chisso PP K1016 manufactured by Chisso was used as the raw material for the polypropylene cap.)
<Water bottle drop test>
The following test method was implemented as a test for comparing the heat resistance and impact resistance of the cap liner material composition.
[0032]
A 500 ml PET bottle was filled with hot water at 85 ° C., and a cap-clamping process (clamping torque: 15 kg-cm) was performed using a good cap produced by cap liner moldability evaluation. Then, after putting in a retort sterilization pot and performing the process for 120 degreeC-20 minutes, it stood to cool to normal temperature, and the test bottle was obtained.
[0033]
Twenty dummy bottles (untreated retort bottles) were placed in a cardboard carton case containing 24 boxes per box (4 x 6 levels), and only four upper test bottles were placed.
[0034]
The carton case was placed so that the four test bottles were in the upper stage, and the carton case was gradually tilted so that it fell on its own weight so that the top surface of the cap became the impact surface, and dropped.
[0035]
The test bottle was repeatedly dropped until the liquid leaked, and the test bottles that had been leaked were counted as the number of drops until that time. (However, the maximum number of drops was 30.)
Example 1
As a composition for a cap liner material, a propylene resin (a product obtained by adding 0.2% by weight of nucleating agent ADK STAB NA-11 to Chisso Polypro K1016 manufactured by Chisso, MFR 5.0 g / 10 min, crystallization temperature 133 ° C., hereinafter referred to as PP- 1) 60% by weight, polypropylene-ethylene / α-olefin copolymer (Montel Catalloy KS-357P (polypropylene-ethylene / propylene copolymer) MFR 25 g / 10 min, melting point 142 ° C., hereinafter referred to as PER-1) 40 0.3 parts by weight of erucamide was added to 100 parts by weight of 100% by weight to obtain a composition.
Using the composition, liner moldability evaluation and a water bottle drop test were performed, and the test results are shown in Table 1.
[0036]
Example 2
In Example 1, PP-1 was changed to 80% by weight and PER-1 was changed to 20% by weight, and a composition was obtained in the same manner as in Example 1. The test results are shown in Table 1.
[0037]
Example 3
In Example 1, PP-1 was changed to 40% by weight and PER-1 was changed to 60% by weight, and a composition was obtained in the same manner as in Example 1. The test results are shown in Table 1.
[0038]
Example 4
In Example 1, PP-1 is a propylene-based resin (a product obtained by adding 0.2% by weight of nucleating agent ADK STAB NA-11 to Chisso Polypro K1800 manufactured by Chisso, MFR 21.0 g / 10 min, crystallization temperature 134 ° C., hereinafter PP To 2) and a composition was obtained in the same manner as in Example 1. The test results are shown in Table 1.
[0039]
Example 5
In Example 1, PER-1 was changed to a polypropylene-ethylene / α-olefin copolymer (Montel Catalloy X500 (polypropylene-ethylene / butene copolymer), MFR 9 g / 10 min, melting point 162 ° C., hereinafter referred to as PER-2). Then, a composition was obtained in the same manner as in Example 1. The test results are shown in Table 1.
[0040]
Comparative Example 1
PP-1 20% by weight, hydrogenated styrene-ethylene-butylene block copolymer rubber (Shell Japan Clayton G1651, hereinafter referred to as SEBS) 40% by weight, liquid paraffin (Esso Petroleum Corporation Christol J-262; viscosity ( 40 parts by weight of JIS K2283-83) 51 mm2 / S (40 ° C., hereinafter referred to as flow para) and 0.3 part by weight of erucic acid amide were added, and a composition was obtained in the same manner as in Example 1. The test results are shown in Table 1.
[0041]
Comparative Example 2
0.3 parts by weight of erucic acid amide was added to 100 parts by weight of PP-1, and a composition was obtained in the same manner as in Example 1. The test results are shown in Table 1.
[0042]
Comparative Example 3
In Example 1, PP-1 was changed to a propylene-based resin (Nisso-made Chisso Polypro K1016, MFR 5.0 g / 10 min, crystallization temperature 114 ° C., hereinafter referred to as PP-3), and the composition was changed in the same manner as in Example 1. Obtained. The test results are shown in Table 1.
[0043]
Comparative Example 4
In Example 1, PER-1 was converted into a polypropylene-ethylene / α-olefin copolymer (Montel Catalloy 5C30F (polypropylene-ethylene / propylene copolymer), MFR 5.5 g / 10 min, melting point 130 ° C., hereinafter referred to as PER-3). The composition was obtained in the same manner as in Example 1. The test results are shown in Table 1.
[0044]
Comparative Example 5
In Example 1, PP-1 was changed to 15% by weight and PER-1 was changed to 85% by weight, and a composition was obtained in the same manner as in Example 1. The test results are shown in Table 1.
[0045]
Comparative Example 6
In Example 1, PER-1 was converted to a polypropylene-ethylene / α-olefin copolymer (Montel Catalloy KS-353P (polypropylene-ethylene / propylene copolymer), MFR 0.45 g / 10 min, melting point 142 ° C., hereinafter PER-4. The composition was obtained in the same manner as in Example 1. The test results are shown in Table 1.
[0046]
[Table 1]

【Effect of the invention】
The composition for a cap liner material of the present invention has both heat resistance, flexibility, and cap liner moldability, which is not found in a conventionally known composition for a cap liner material, and the liner performance even after high-temperature sterilization treatment. Is useful to keep.

Claims (3)

Propylene polymer (ii) 30 to 90 having a melt flow rate (JIS K7210-76; 230 ° C.-2.16 kg load) of 0.1 to 100 g / 10 min and a crystallization temperature of 120 ° C. or more by addition of a nucleating agent. % By weight, melt flow rate (JISK7210-76; 230 ° C.-2.16 kg load) is 1 to 50 g / 10 min, melting point is 140 ° C. or higher, and the ethylene / butene copolymer component is fine in a matrix mainly composed of polypropylene. Polypropylene-ethylene butene copolymer (b) having a dispersed structure (b) 70 to 10% by weight (total of (a) and (b) is 100% by weight) Composition. A cap comprising the cap liner made of the composition for a cap liner material according to claim 1. A packaging container comprising the cap according to claim 2.