JP2000297198A - Cap liner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cap liner which is excellent in moldability, heat resistance and preservation of contents and facilitates uncapping in practical use by compounding a hydrogenated block copolymer mixture with a polypropylene resin, a polyethylene resin and a hydrocarbon oil in a specified ratio. SOLUTION: A hydrogenated block copolymer having a number average mol.wt. (Mn) of 150,000-400,000 and prepared by hydrogenating a block copolymer comprising 15-40 wt.% polymer block A formed mainly from at least two vinylaromatic compounds and polymer block B formed mainly from at least one conjugated diene is mixed with a hydrogenated block copolymer having an Mn of 30,000-149,000 and prepared by hydrogenating a block copolymer comprising 8-35 wt.% polymer block A formed mainly from at least one vinylaromatic compound and polymer block B, the wt. ratio of the former hydrogenated block copolymer to the latter being (5/95)-(95/5). The resultant mixture in an amount of 100 pts.wt. is compounded with 10-100 pts.wt. polypropylene resin having an MFR of 0.1-10 g/10 min, 0-70 pts.wt. polyethylene resin having an MFR of 1-20 g/10 min and 30-150 pts.wt. hydrocarbon oil and is then molded to give cap liners.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cap liner which is excellent in moldability, heat resistance and preservation of contents, and which facilitates opening in practical use, and particularly a packing material for a metal or resin screw cap. And a cap liner suitable for beverages.

[0002]

2. Description of the Related Art Conventionally, as a liner material for a beverage cap, for example, a liner material described in JP-A-2-57569 is known. This liner material was a composition comprising a hydrogenated styrene-butadiene block copolymer, liquid paraffin, and polypropylene. Although the heat resistance effect was recognized, it was inferior in moldability. (Because the melt viscosity is highly dependent on the shear rate and the die swell is small, stable dimensions cannot be obtained when forming into a sheet or rod shape.)
JP-A-34085 proposes a cap liner comprising an ethylene-based polymer, a hydrogenated block copolymer elastomer and a higher fatty acid amide, which has excellent storage properties and excellent openability in practical use. However, this cap liner has a drawback of poor heat resistance. Further, JP-A-7-76360 discloses a composition for a cap liner material comprising a hydrogenated styrene-butadiene block copolymer, liquid paraffin, polypropylene, and polyethylene and having heat resistance and a good opening torque. . However, the heat resistance of this composition is substantially inadequate.
There was a drawback that the sealing property was deteriorated when exposed to a temperature of not less than ° C for a long time.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional technical problems, and is excellent in moldability, heat resistance, and storage stability of contents, and can be easily opened in practical use. To provide a cap liner.

[0004]

That is, the present invention relates to (a) 100 parts by weight of a hydrogenated block copolymer mixture of the following (a-1) and (a-2): (a-1) at least two A block copolymer obtained by hydrogenating a block copolymer composed of a polymer block A mainly composed of a vinyl aromatic compound and a polymer block B mainly composed of at least one conjugated diene compound,
The number average molecular weight is not less than 150,000 and not more than 400,000, and the polymer block A is 15 to 40% by weight of the copolymer.
(A-2) a polymer block A mainly composed of at least one vinyl aromatic compound and a polymer mainly composed of at least one conjugated diene compound. A block copolymer obtained by hydrogenating a block copolymer consisting of a united block B,
A hydrogenated block copolymer having a number average molecular weight of 30,000 or more and 149000 or less, and the polymer block A constitutes 8 to 35% by weight of the copolymer: 5 to 95 parts by weight. 1 to 10 g / 10 min of polypropylene resin: 10 to 100 parts by weight (c) Polyethylene resin having a melt flow rate of 0.1 to 10 g / 20 min: 0 to 70 parts by weight (d) Hydrocarbon oil: 30 to 150 parts by weight (e) Higher fatty acid amide: 0.1 to 2.0.1 parts by weight based on 100 parts by weight of the total amount of components (a), (b), (c) and (d).
A cap liner comprising an elastomer composition comprising 0 parts by weight.

Hereinafter, the present invention will be described in detail. Examples of the vinyl aromatic compound constituting the hydrogenated block copolymer as the component (a) of the present invention include styrene and α.
One or more of methylstyrene, vinyltoluene, p-tert-butylstyrene and the like can be selected;
Among them, styrene is preferred.

As conjugated diene compounds, for example, butadiene, isoprene, 1,3-pentadiene, 2,2
One or more of 3-dimethyl-1,3-butadiene and the like can be selected, and among them, butadiene, isoprene and a combination thereof are preferable. The polymer block B mainly composed of a conjugated diene compound before hydrogenation can be arbitrarily selected from microstructures in the block. For example, in the case of a polybutadiene block, a 1,2-vinyl bond structure is used. Is 20 to 50% by weight, preferably 25 to 45% by weight, and the polyisoprene block has 80% by weight of 1,4-vinyl bonds.
Or more, preferably 90% by weight or more.

In the present invention, the hydrogenated block copolymer comprises:
Two types (a-1) and (a-2) are used. The hydrogenated block copolymer (a-1) has a number average molecular weight of 15
0000 or more and 400,000 or less, preferably 1800
00 or more and 350,000 or less, more preferably 200
000 or more and 300,000 or less, and the polymer block A is 15 to 40% by weight of the copolymer, preferably 20 to 3% by weight.
Make up 5% by weight.

The number average molecular weight of the hydrogenated block copolymer is 1
If it is 50,000 or less, the strength and heat resistance of the elastomer composition decrease, which is not preferable. On the other hand, when the number average molecular weight of the hydrogenated block copolymer exceeds 400,000, the moldability (fluidity) of the elastomer composition is lowered, and the appearance of the molded product is unfavorably deteriorated. If the polymer block A is less than 15% by weight of the copolymer, the strength and heat resistance of the elastomer composition are undesirably reduced. on the other hand,
When the amount of the polymer block A exceeds 40% by weight of the copolymer, the flexibility of the elastomer composition decreases,
It is not preferable because the sealing property is reduced.

The hydrogenated block copolymer (a-2) has a number average molecular weight of 30,000 or more and 149000 or less, preferably 50,000 or more and 120,000 or less, more preferably 60,000 or more and 90000 or less. 8-35% by weight of the copolymer, preferably 10%
-30% by weight, more preferably 15-25% by weight. Number average molecular weight of the hydrogenated block copolymer is 300
If it is less than 00, the strength and heat resistance of the elastomer composition are undesirably reduced. On the other hand, if the number average molecular weight of the hydrogenated block copolymer exceeds 149000, the moldability (fluidity) of the elastomer composition is lowered, and the appearance of the molded product is unfavorably deteriorated. Further, if the amount of the polymer block A is less than 10% by weight of the copolymer, the strength and heat resistance of the elastomer composition are undesirably reduced. on the other hand,
If the polymer block A exceeds 35% by weight of the copolymer, the flexibility of the elastomer composition is undesirably reduced. The molecular weight distribution of the hydrogenated block copolymers (a-1) and (a-2) [the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) (Mw / Mn)] is 5 or less;
Preferably it is 2 or less, more preferably 1.5 or less. If the molecular weight distribution exceeds 5, the strength and heat resistance of the elastomer composition are not sufficient, which is not preferable. The molecular weight and the molecular weight distribution described in the present specification can be determined by, for example, GPC (Gel
It is measured by the Permeation Chromatography method. In GPC analysis, the molecular weight can be calculated using a calibration curve prepared with standard polystyrene.

The hydrogenated block copolymer used as the component (a-1) in the present invention comprises at least two polymer blocks A mainly composed of a vinyl aromatic compound and at least one conjugated diene compound. And a block copolymer obtained by hydrogenating a block copolymer consisting of a polymer block B, for example, ABA, BAB-
A, ABABA, BABAB and the like.

The hydrogenated block copolymer used as the component (a-2) in the present invention comprises at least one polymer block A mainly composed of a vinyl aromatic compound and at least one conjugated diene compound. Is a block copolymer obtained by hydrogenating a block copolymer comprising a polymer block B mainly composed of, for example, AB, AB-
A, BABA, ABABA, BAB
-AB and the like.

In the present invention, (a-1) or (a-
2) The polymer block A mainly composed of a vinyl aromatic compound of the hydrogenated block copolymer used as the component, and the polymer block B mainly composed of the conjugated diene compound are each a vinyl aromatic compound or a vinyl aromatic compound in each polymer block. Conjugated diene compound distribution is random or tapered (the monomer component increases or decreases along the molecular chain)
Or, it may be partially block-shaped or an arbitrary combination thereof. When there are two or more polymer blocks A and B, each polymer block may have the same structure or different structure. It may be. As used herein, the expression "predominantly" means that the corresponding monomer unit is at least 5 of the polymer block.
0% by weight or more, preferably 70% or more.

The mixing ratio of the hydrogenated block copolymer (a-1) and the hydrogenated block copolymer (a-2) is such that the total amount of the hydrogenated block copolymer is 100 parts by weight. 5 to 95 parts by weight of the polymer (a-1) and 5 to 95 parts by weight of the block copolymer (a-2), preferably 30 to 90 parts by weight of the block copolymer (a-1); 10 to 70 parts by weight of the block copolymer (a-2), more preferably 50 to 80 parts by weight of the block copolymer (a-1),
The amount of the block copolymer (a-2) is 20 to 50 parts by weight. If the amount of the block copolymer (a-1) is less than 5 parts by weight, the strength and heat resistance of the elastomer composition are undesirably reduced. If the amount of the block copolymer (a-1) exceeds 95 parts by weight, the moldability (fluidity) of the elastomer composition is lowered, and the appearance of the molded product is unfavorably deteriorated.

The production method of these block copolymers is not limited as long as they have the above-mentioned structure. For example, a method using a lithium catalyst by a method described in Japanese Patent Publication No. 40-23798 is used. Thus, a vinyl aromatic compound-conjugated diene compound block copolymer before hydrogenation can be synthesized in an inert solvent. As the method of hydrogenation, for example, Japanese Patent Publication No. 42-8704,
JP-B-43-6636, JP-A-60-22014
7, JP-A-61-33132 or JP-A-62-207303. At least 80%, preferably at least 90%, of the aliphatic double bonds derived from the conjugated diene compound are hydrogenated, while less than 20%, preferably less than 10%, of the vinyl aromatic compound is hydrogenated. To be selected. The hydrogenation rate of the hydrogenated block copolymer can be easily known by infrared spectroscopy or nuclear magnetic resonance analysis.

Next, the component (b) of the present invention is a polypropylene resin. As the polypropylene resin, propylene homopolymer or propylene and α-
It is a copolymer with an olefin (hereinafter abbreviated as propylene-based resin). In the case of a copolymer of propylene and an α-olefin having 2 to 8 carbon atoms, the α-olefin in the copolymer may be ethylene, butene-1, isobutene, pentene-1, hexene-1, 4-methylpentene- 1, octene-1 and the like. The proportion of α-olefin is 30% by weight or less. These propylene-based resins can be synthesized by a conventionally known method, for example, a propylene homopolymer synthesized using a Ziegler-Natta type catalyst, or a copolymer of random or block propylene and an α-olefin. Is raised. In order to obtain an elastomer composition having excellent heat resistance and moldability, it is preferable to use a polypropylene resin as the polyolefin resin.

The melt flow rate of these polyolefin resins (ASTM D1238, 230 ° C., 2.1
A value measured according to a 6 kg load. (Hereinafter abbreviated as MFR) is 0.1 to 10 g / 10 min, preferably 0.3 to 6 g / min.
g / 10 minutes. If the MFR is less than 0.1 g / 10 minutes, the melt viscosity of the elastomer composition is high, the moldability (flowability) of the elastomer composition is reduced, and the appearance of the molded product is unfavorably deteriorated. In addition, MFR is 10 g
If it exceeds / 10 minutes, the strength, heat resistance, and moldability (drawdown during extrusion molding and decrease in die swell) of the elastomer composition are undesirably reduced.

In the present invention, the blending amount of the polypropylene resin as the component (b) is 100 parts by weight of the hydrogenated block copolymer.
10 to 100 parts by weight, preferably 15 to 100 parts by weight, based on parts by weight
60 parts by weight, more preferably 20 to 40 parts by weight. If the amount of the polyolefin-based resin is less than 10 parts by weight, the heat resistance and the moldability (flowability) of the elastomer composition are lowered, and the appearance of the molded product is unfavorably deteriorated. If the amount of the polypropylene resin exceeds 100 parts by weight, the flexibility of the elastomer composition and the sealing property of the liner are undesirably reduced.

The component (c) in the present invention is a polyethylene resin, specifically a homopolymer of ethylene and / or a copolymer of ethylene and an α-olefin. In the case of a copolymer of propylene and an α-olefin having 2 to 8 carbon atoms, the α-olefin in the copolymer may be ethylene, butene-1, isobutene, pentene-1, hexene-1, 4-methylpentene- 1, octene-1 and the like. The ratio of α-olefin is 30% by weight.
The following are used:

The MFR of these polyethylene resins is 0.1 to 20 g / 10 min, preferably 3 to 15 g / 10 min.
Minutes. If the MFR is less than 0.1 g / 10 minutes, the melt viscosity of the elastomer composition is high, the moldability (flowability) of the elastomer composition is reduced, and the appearance of the molded product is unfavorably deteriorated. On the other hand, if the MFR exceeds 20 g / 10 minutes, the strength, heat resistance and moldability (drawdown and die swell during extrusion molding) of the elastomer composition are undesirably reduced.

The amount of the polyethylene resin as component (c) in the present invention is from 0 to 70 parts by weight, preferably from 5 to 50 parts by weight, more preferably from 10 to 100 parts by weight, based on 100 parts by weight of the hydrogenated block copolymer. 45 parts by weight. If the amount of the polyethylene resin exceeds 70 parts by weight, the heat resistance of the elastomer composition and the sealing property of the liner are undesirably reduced.

Component (d) in the present invention is a hydrocarbon oil, which has the effect of improving the flexibility and processability of the resulting composition, and is a non-aromatic mineral oil or a liquid or low molecular weight oil. Synthetic softeners are suitable. As the non-aromatic mineral oil, generally known paraffin oils and naphthenic oils can be used. Among them, paraffin oils having an aromatic ring component of 10% by weight or less are preferable. The blending amount of the hydrocarbon oil is 30 to 150 parts by weight, preferably 40 to 120 parts by weight, more preferably 50 to 100 parts by weight, based on 100 parts by weight of the hydrogenated block copolymer.
90 parts by weight. If the blending amount of the hydrocarbon oil exceeds 150 parts by weight, the heat resistance of the elastomer composition is lowered, and the transfer of the oil from the liner material is not preferable.

Further, the composition of the present invention may contain an inorganic filler, a stabilizer, a lubricant, a coloring agent, a silicone oil, a flame retardant and the like, if necessary. As inorganic fillers,
For example, calcium carbonate, talc, magnesium hydroxide,
Mica, barium sulfate, silica (white carbon),
Examples include titanium oxide and carbon black. Examples of the stabilizer include a hindered phenol-based antioxidant, a phosphorus-based heat stabilizer, a hindered amine-based light stabilizer, and a benzotriazole-based UV absorber.

A lubricant may be added to the composition of the present invention in order to reduce the torque at the time of opening. Preferred examples include higher fatty acid amides, stearic acid, stearic acid esters and stearic acid. Among them, metal salts and the like are mentioned, and higher fatty acid amides are preferable.
Such higher fatty acid amides include oleic acid amide, erucic acid amide, stearic acid amide, palmitic acid amide, lauric acid amide, behenic acid amide, methylene bisstearyl amide, ethylene bis stearyl amide, ethylene bis oleyl amide, ethylene bis lauryl amide, Stearyl oleylamide, N-stearyl erucamide, N-oleyl palmitoamide and the like can be mentioned.

When the higher fatty acid amide is added, the addition amount is preferably 0.1 to 3.0 parts by weight, based on 100 parts by weight of the total amount of the components (a), (b), (c) and (d). Is 0.2 to 1.0 part by weight. If the amount of the higher fatty acid amide is less than 0.1 part by weight, the torque at the time of opening the cap is undesirably increased. On the other hand, when the addition amount of the higher fatty acid amide exceeds 3.0 parts by weight, bleeding of the higher fatty acid amide occurs and the sealing property decreases, which is not preferable.

In general, any method known in the art for blending polymer components may be used to prepare the elastomer composition of the present invention. In order to obtain the most homogeneous blend, a method of melt-kneading using various kinds of kneading machines such as commonly used mixing rolls, kneaders, Banbury mixers and extruders is desirable. Prior to melt-kneading, these blends were dry-blended in advance using a mixer such as a Henschel mixer, tumbler or ribbon blender,
A homogeneous elastomer composition can be obtained by melt-kneading the mixture. As a method for forming the cap liner, a known liner forming method is used to form the cap liner into the cap shell. As a liner forming method, for example,
After forming the resin composition into a sheet having a thickness of 0.5 to 1.0 mm, punching into a diameter corresponding to the shape of the cap, inserting into the cap, and bonding, a certain amount of molten resin extruded by an extruder is used as a cap. , And embossed under cooling to form a liner shape. Further, the composition of the present invention has an advantage that it can be recycled because of its excellent thermal stability.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the examples and comparative examples, the test methods used for various evaluation methods are as follows. (1) Hardness [-]: JIS K6301, A type, 2
Measured at 3 ° C. (2) Tensile strength [kgf / cm2]: JIS K630
No. 1 and No. 3 dumbbells and 2 mm thick pressed sheets were used as samples. (3) Elongation [%]: JIS K6301, No. 3 dumbbell, 2 mm thick pressed sheet was used as a sample. (4) Melt flow rate (MFR) [g / 10 min]:
ASTM D1238 was measured at 230 ° C. under a load of 2.16 kg. (5) Moldability: The composition was molded in a 28 mmφ polypropylene cap shell by an in-shell mold method to form a liner, and various test caps were produced (cylinder temperature C1: 180 ° C, C2: 190).
° C, C3: 190 ° C, nozzle temperature: 200 ° C). Each of the caps thus prepared was visually observed for its surface condition, appearance, and the like, and the appearance was evaluated as good (○), slightly poor (△), and poor (×). (6) Opening torque: 40 cc for a 500 cc glass bottle
Using a cap filled with 0 cc of carbon dioxide and fitted with a liner made of the composition shown in Table 1, sealing was performed at a top load of 270 kgf and a side torque of 8 kgf-cm. As the carbon dioxide gas water, used was one in which about 2.5 times the volume of carbon dioxide gas was dissolved in the same amount of water at 23 ° C. This container is 5
After storage at 30 ° C. for 30 days, the opening torque was measured with a torque meter. The evaluation was performed as follows. ：: Torque 10 to 16 kgf-cm △: Torque 5 kgf-cm or more and less than 10 kgf-cm or more than 16 kgf-cm and 20 kgf-cm or less ×: Torque less than 5 kgf-cm or 20 kgf-cm
(7) Sealing and storage test: A 500 cc glass bottle was filled with 400 cc of carbon dioxide gas, and a cap equipped with a liner composed of the composition shown in Table 1 was used to obtain a top load of 270 kgf and a side torque of 8 kgf- cm
And sealed. As the carbon dioxide gas water, used was one in which about 2.5 times the volume of carbon dioxide gas was dissolved in the same amount of water at 23 ° C. After leaving this glass container at 70 ° C. for 30 days, gas leakage was inspected. The evaluation was performed as follows. ：: All or most of them are not leaked. (0/10/1 /
10) X: All or most of them leak. (6/10 to 10/1
0) Δ: middle of the above. (2/10 to 5/10) The components used in Examples and Comparative Examples are as follows.

Component (a-1) -1 having the structure of ABA, having a number average molecular weight of 270000,
Molecular weight distribution 1.2, bound styrene content 31% by weight, 1,2-vinyl bond content of polybutadiene part before hydrogenation was 38
A hydrogenated block copolymer of a styrene / butadiene block copolymer having a hydrogenation rate of 99% by weight and a polybutadiene portion of 99% was synthesized by the method described in JP-A-60-220147.

Component (a-1) -2 having the structure of ABA, having a number average molecular weight of 290000,
Molecular weight distribution 1.2, bound styrene content 28% by weight, 1,4-bond content of polyisoprene portion before hydrogenation 94% by weight, 3,4-bond content 6% by weight, hydrogenation rate of polyisoprene portion A hydrogenated block copolymer of 99% styrene / isoprene block copolymer was obtained by
No. 47 was synthesized.

Component (a-1) -3 has the structure of BABA and has a number average molecular weight of 21,000.
Styrene / butadiene block copolymer having a molecular weight distribution of 1.2, a bound styrene content of 34% by weight, a 1,2-vinyl bond content of the polybutadiene portion before hydrogenation of 36% by weight, and a hydrogenation rate of the polybutadiene portion of 99%. Was synthesized by the method described in JP-A-60-220147.

Component (a-2) -1 having the structure of ABA, having a number average molecular weight of 90000, a molecular weight distribution of 1.10, a bound styrene content of 21% by weight, and 1,2 of the polybutadiene portion before hydrogenation. 38 vinyl bonds
A hydrogenated block copolymer of a styrene / butadiene block copolymer having a hydrogenation rate of 99% by weight and a polybutadiene portion of 99% was synthesized by the method described in JP-A-60-220147.

Component (a-2) -2 having the structure of BABA and having a number average molecular weight of 6500
0, molecular weight distribution 1.13, bound styrene content 20% by weight,
A hydrogenated block copolymer of a styrene / butadiene block copolymer having a 1,2-vinyl bond content of 36% by weight in the polybutadiene portion before hydrogenation and a hydrogenation rate of 99% in the polybutadiene portion is disclosed in JP-A-60-220147. It was synthesized by the method described in the gazette.

Component (a-2) -3 having the structure of ABA, having a number average molecular weight of 55000, a molecular weight distribution of 1.1, an amount of bound styrene of 25% by weight, and a polyisoprene part of 1,1 before hydrogenation. 4- 94% by weight of binding;
A hydrogenated block copolymer of a styrene / isoprene block copolymer having a 3,4-bond content of 6% by weight and a hydrogenation rate of the polyisoprene portion of 99% was prepared by the method described in JP-A-60-220147.
The synthesis was carried out according to the method described in Japanese Patent Publication No.

Component (a-2) -4 having the structure of ABA, having a number average molecular weight of 25,000, a molecular weight distribution of 1.14, an amount of bound styrene of 21% by weight, and 1,2 of the polybutadiene portion before hydrogenation. 38 vinyl bonds
A hydrogenated block copolymer of a styrene / butadiene block copolymer having a hydrogenation rate of 99% by weight and a polybutadiene portion of 99% was synthesized by the method described in JP-A-60-220147.

Component (a-2) -5 having the structure of BABA and having a number average molecular weight of 7000
Styrene / butadiene block copolymer having a molecular weight distribution of 1.1, a bound styrene content of 39% by weight, a 1,2-vinyl bond content of a polybutadiene portion before hydrogenation of 36% by weight, and a hydrogenation rate of the polybutadiene portion of 99%. Was synthesized by the method described in JP-A-60-220147.

Component (b) -1 Made by JPO, Shaw Allomer SK711 (block type polypropylene), MFR: 1 g / 10 minutes Component (b) -2 Made by JPO, Shaw Allomer MK511 (block type polypropylene), MFR: 15 g / 10 Component (c) JPO, LDPE, L1850A, MFR: 12g /
10 minutes.

Component (c) A paraffinic oil manufactured by Idemitsu Kosan. Diana Process Oil PW-90. (Kinematic viscosity; 90 cSt).

[0037]

Examples 1 to 10 As a hydrogenated block copolymer (a-
1) -1 to 3 and (a-2) -1 to 3, (b) -1 as a polypropylene resin, (c) -1 as a polyethylene resin, and (d) as a hydrocarbon oil. After blending with a Henschel mixer at the respective ratios shown in Tables 1, 2 and 3, the mixture was melt-kneaded at 220 ° C. in a 45 mm-diameter twin-screw extruder to obtain pellets of an elastomer composition. Was. This was evaluated by the above test method, and the results are shown in Tables 1, 2 and 3. From these results, the cap liner made of the elastomer composition of the present invention has heat resistance,
It is clear that the sealability is excellent, and the openability and processability are also good.

[0038]

[Table 1]

[0039]

[Table 2]

[0040]

[Table 3]

[0041]

Comparative Examples 1 to 10 As a hydrogenated block copolymer (a-
Tables 4, 5, and 6 using 1) -1, (a-2) -1, 4, 5; using (b) -1, 2 as a polyolefin-based resin; and (c) as a hydrocarbon oil. At the respective ratios shown in Table 1, kneading and evaluation were performed in the same manner as in the methods of Examples 1 to 10. The results are shown in Tables 4, 5, and 6. From these results, it is clear that a composition outside the range of the present invention is inferior in any performance or processability.

[0042]

[Table 4]

[0043]

[Table 5]

[0044]

[Table 6]

[0045]

The cap liner made of the elastomer composition obtained by the present invention is excellent in molding processability, heat resistance and content preservability, and is easy to open in practical use, particularly a cap liner. It can be suitably used for a cap liner for beverages as a packing material for a screw cap made of metal or resin.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 91:00 23:10 23:04) (C08L 53/02 23:10 23:04) F-term (Reference) 4F071 AA15 AA15X AA20 AA20X AA21X AA71 AA75 AA81 AC12 AE11 AH05 BA01 BC01 BC07 4J002 AE05W BB054 BB143 BB153 BP01X EP016 EP026 FD176 GG01

Claims (4)

[Claims] (A) The following (a-1) and (a-2)
100 parts by weight of a hydrogenated block copolymer mixture of (a-1): a polymer block A mainly composed of at least two vinyl aromatic compounds and a polymer block B mainly composed of at least one conjugated diene compound A block copolymer obtained by hydrogenating a block copolymer consisting of
The number average molecular weight is not less than 150,000 and not more than 400,000, and the polymer block A is 15 to 40% by weight of the copolymer.
(A-2) a polymer block A mainly composed of at least one vinyl aromatic compound and a polymer mainly composed of at least one conjugated diene compound. A block copolymer obtained by hydrogenating a block copolymer consisting of a united block B,
A hydrogenated block copolymer having a number average molecular weight of 30,000 or more and 149000 or less, and the polymer block A constitutes 8 to 35% by weight of the copolymer: 5 to 95 parts by weight. 1-10 g / 10 min polypropylene resin: 10-100 parts by weight (c) Polyethylene resin having a melt flow rate of 0.1-20 g / 10 min: 0-70 parts by weight (d) Hydrocarbon oil: 30- A cap liner comprising an elastomer composition comprising 150 parts by weight. 2. The method according to claim 1, wherein the vinyl aromatic compound is styrene,
The conjugated diene compound is butadiene or isoprene or a combination thereof.
The cap liner as described. 3. The cap liner according to claim 1, wherein the hydrocarbon oil is a non-aromatic paraffin oil. 4. The elastomer composition according to claim 1, wherein the higher fatty acid amide is composed of the components (a), (b), (c) and (d) in a total amount of 1
2. The cap liner according to claim 1, wherein the content is 0.1 to 3.0 parts by weight based on 00 parts by weight.