JP2002264155A - Cap liner and cap - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin cap which has a characteristic of low carbon dioxide permeability and does not spoil original flavor of a content in a container for a long time. SOLUTION: A laminated body used for a cap liner or the resin cap is constituted of a thermoplastic resin (a) and a low carbon dioxide permeable resin (b) with a carbon dioxide gas permeability of 1.0×10<-16> mol×m/(m<2> ×s×Pa) or less, and has a laminated structure in the plane direction and with a lamination thickness constitutional ratio of the thermoplastic resin (a): the low carbon dioxide gas permeable resin (b)=100:0.1-100:100.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cap liner and a cap formed by laminating a carbon dioxide low-permeability resin with a thermoplastic resin. It is effective to use it for applications.

When used for bottles containing contents in which carbon dioxide is dissolved, such as carbonated drinking water, etc., it is possible to prevent permeation and leakage of carbon dioxide and maintain the flavor of the contents for a long time. is there. In addition, the permeability of carbon dioxide is substantially proportional to the permeability of oxygen, and also has a low permeability to oxygen. Also when used for bottles, it is possible to prevent permeation and mixing of oxygen and to maintain the flavor of the contents for a long time.

[0003]

2. Description of the Related Art Generally, a cap liner and a cap are produced by various molding methods using a generally known thermoplastic resin. For cap liners,
In general, low-density polyethylene resin,
When the cap is made of a styrene-based elastomer resin, a resin such as a polypropylene-based resin or high-density polyethylene has been suitably used.

[0004] In the case of a large carbonated drinking water PET bottle (2.0 liter type or 1.5 liter type), permeation leakage of carbon dioxide from the cap portion is as follows.
Compared to the leakage of carbon dioxide through the bottle having a large surface area, the leakage rate was very small, and was not a problem to be noticed.

[0005] However, small carbonated drinking water PET bottles (50) which have recently been introduced to the market and whose quantity has increased dramatically have been increasing.
(0 ml type and 350 ml type), the leakage of carbon dioxide through the cap is not negligible compared to the leakage through the bottle with a reduced surface area. And permeation leakage of carbon dioxide from the cap
One cause and a problem.

[0006] In addition, this is the same situation in which the contents are oxidized by permeation and mixing of oxygen, thereby causing flavor inhibition.

[0007] Therefore, there has been a demand for a cap liner and a cap for preventing the bottle contents from hindering the flavor.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a cap liner and a cap having low carbon dioxide permeability and low oxygen permeability. is there.

[0009]

The inventors of the present invention have conducted intensive studies and have found that a cap liner and a cap having a laminated structure of a thermoplastic resin and a resin having a low carbon dioxide permeability of a certain value or less are used. As a result, they have found that the flavor of the contents in the packaging container can be maintained for a long period of time, and have completed the invention.

That is, the present invention relates to a thermoplastic resin (a) and carbon dioxide having a carbon dioxide gas permeability coefficient (JIS K7126-87) of 1.0 × 10 ^-16 mol × m / (m ² × s × Pa) or less. A laminated body composed of a low-permeability resin (b), which has a laminated structure in the plane direction, and the laminated thickness composition ratio is thermoplastic resin (a) thickness: carbon dioxide low-permeability resin (b) thickness = The present invention relates to a cap liner and a cap having a ratio of 100: 0.1 to 100: 100.

The thermoplastic resin used in the present invention (a)
Examples thereof include polyolefin-based resins, polyester-based resins, ABS resins, styrene-based resins, olefin-based elastomers, and styrene-based elastomers.

In the case of a cap liner, generally known cap liner material compositions can be used. Specifically, it is at least one resin selected from the group consisting of polyolefin-based resins, olefin-based elastomers, and styrene-based elastomers. Specifically, polypropylene, high-density polyethylene,
Linear low density polyethylene, branched low density polyethylene, ethylene-vinyl acetate copolymer, ethylene-propylene copolymer rubber, ethylene-butene copolymer rubber, styrene-butadiene block copolymer rubber, styrene-
Ethylene-butene block copolymer rubber, styrene-ethylene-propylene block copolymer rubber, styrene-
There is isoprene block copolymer rubber and the like.

In the case of the cap, a generally known composition for a cap material can be used. Specifically, it is a polyolefin resin, specifically, polypropylene, high-density polyethylene, linear low-density polyethylene, or branched low-density polyethylene.

Among the polyolefin resins, gel
Monodispersity (weight average molecular weight / number average molecular weight) in permeation chromatography measurement is 1.5 to
It is more preferable to use a polyolefin-based resin having a range of 3.0, because the influence of the low molecular weight component on the flavor of the content is small. In addition, the measuring method of Mw and Mn is as follows.
Gel permeation chromatography (manufactured by Nippon Millipore Co., Ltd., apparatus name "ALC / GPC150C" (column: manufactured by Tosoh Corporation, trade name "GMHHR-H")
(S) ", 3 solvents, 1,2,4-trichlorobenzene, temperature: 140 ° C., flow rate 1.0 ml / min, injection concentration 1
mg / ml, injection volume 300 μl).
The column elution volume was calibrated by universal calibration using standard polystyrene manufactured by Tosoh Corporation.

The carbon dioxide low permeability resin (b) used in the present invention has a carbon dioxide gas permeability coefficient (JIS K71).
26-87) is 1.0 × 10 ⁻¹⁶ mol × m / (m ² ×
s × Pa) or less, specifically, polyvinyl alcohol resin, ethylene-vinyl alcohol copolymer, polyamide resin, polyester resin, acrylonitrile resin, vinyl chloride resin, vinylidene chloride resin, etc. Can be mentioned.

Among them, an ethylene-vinyl alcohol copolymer (trade name; EVAL manufactured by Kuraray Co., Ltd., manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) which is easily laminated and formed on a thermoplastic resin (a) and has excellent carbon dioxide low permeability Polyamide resins (Nylon manufactured by Ube Industries, Ltd., Nylon manufactured by Unitika, Nylon manufactured by Kanebo Co., Ltd.) and polyester resins (Polyethylene terephthalate manufactured by Teijin Limited, polyethylene terephthalate manufactured by Kuraray Co., Ltd.) The carbon dioxide gas permeability coefficient (JIS K7126-87) of the excellent carbon dioxide low permeability resin (b) is 1.0 × 10 ^-16
mol × m / (m ² × s × Pa) or less and 1.0 ×
If it exceeds 10 ⁻¹⁶ mol × m / (m ² × s × Pa), it is difficult to effectively reduce the carbon dioxide permeability of the cap liner and the cap.

In the cap liner and the cap of the present invention, the thermoplastic resin (a) and the carbon dioxide low-permeability resin (b) have a laminated thickness composition ratio of the thermoplastic resin (a):
Carbon dioxide low permeability resin (b) thickness = 100: 0.1 ~
100: 100, preferably 100: 0.5 to
100: 50.

The thickness ratio of the thermoplastic resin (a) and the carbon dioxide low-permeability resin (b) is 0 with respect to the thermoplastic resin (a) thickness ratio of 100. When the thickness is less than 0.1, the effect of low carbon dioxide permeability is low, and when the thickness of the low carbon dioxide permeability resin (b) exceeds 100, the resin generally has low impact resistance and high water absorption. Performance is impaired.

The cap liner and cap of the present invention are prepared by laminating a thermoplastic resin (a) and a carbon dioxide low-permeability resin (b) by a multilayer molding method such as sheet, press, injection, etc. Alternatively, it is formed into a cap liner or a cap by secondary processing such as compression molding and vacuum molding. In particular, a sheet molding machine, a press molding machine, or the like has a thickness considering the compression ratio (final thickness / sheet molded body thickness) A method of producing a sheet, punching, melting or semi-melting the punched one, inserting it into a cap or a mold, and compression molding (sheet punching compression molding method) to obtain a cap or cap provided with a cap liner. Or a method of hot-cutting a multi-layer extruded melt, inserting it into a cap or a mold, and compression molding It is needed.

The compression ratio when forming the cap liner and the cap is 0.10 to prevent deformation of the laminated structure.
0.99 is preferred.

The laminated structure may be a three-layer structure in which both outer layers are a thermoplastic resin (a) and the inner layer is a carbon dioxide low-permeability resin (b), or a thermoplastic resin (a) and a carbon dioxide low-permeability resin In consideration of the adhesiveness of (b), an appropriate adhesive layer was provided 5
A layer molded body is preferably used. This laminate has a laminated structure in the plane direction.

The cap liner and the cap of the present invention may contain, if necessary, a compatibilizer, a heat stabilizer, a weather stabilizer, and a thermoplastic resin (a) and a carbon dioxide low-permeability resin (b).
Antistatic agent, antiblocking agent, slip agent, surfactant, antifogging agent, dropping agent, crosslinking agent, nucleating agent, pigment, dye, silica, talc, mica, carbon, calcium carbonate, magnesium carbonate, metal stearate Inorganic or organic additives such as wood powder, cork powder, and cellulose powder, and fillers may be blended within a range that does not impair the purpose of the present invention. Among them, a slip agent is often used to adjust the cap opening torque, especially higher fatty acid amides, higher fatty acids, glycerin fatty acid esters, sorbitan fatty acid esters, propylene glycol fatty acid esters, higher alcohol fatty acid esters, and ethylene bis higher fatty acids. Fatty acid amides and the like are used, and preferably, higher fatty acid amides are used. Specifically, caprylic amide, capric amide, lauric amide, myristic amide, palmitic amide, stearic amide, arachidic amide, behenic amide, oleic amide, erucic amide, linoleic amide, Linolenic amides are preferred, with stearamide, oleamide and erucamide being preferred.

The feature of the cap liner and the cap of the present invention is a laminate of a thermoplastic resin and a carbon dioxide low-permeability resin, which suppresses the carbon dioxide (oxygen) permeability of the cap liner and the cap. Sheet,
It is a cap liner and cap made by press, injection molding, etc., which is not present in conventional cap liners and caps, prevents the hindrance of the contents of the container, and has excellent long-term storage properties, especially for carbonated beverages and alcoholic beverages Useful as a packaging container.

[0024]

Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples unless it exceeds the gist of the present invention.

The test and measurement methods used in the present invention are as follows.

<Method for Producing Sample Cap> As a method for producing the test sample cap described below, a sheet punching compression molding method using a laminated sheet produced by press molding was employed.

As a method for manufacturing a cap with a cap liner, specifically, a press sheet is prepared by pressing a material of each layer to an arbitrary thickness at an appropriate temperature in advance so that the entire sheet thickness becomes 0.7 mm. Again, stack the prepared press sheets in the order of configuration, heat press mold,
Integrate. The sheet compact was punched out into a circular shape so as to have a weight of about 0.3 g, melted by heating with hot air at 200 ° C. for 2 minutes, and inserted into the inner top surface of a 28 mmφ type polypropylene resin cap. Immediately, it was pressurized and cooled with a pressing die, and the cap liner was adjusted to a cap liner shape such that the top surface of the cap liner was 0.4 mm, thereby producing a sample cap.

As a method of manufacturing the cap, specifically,
A press sheet is prepared by press-forming the material of each layer to an arbitrary thickness at an appropriate temperature so that the overall thickness of the sheet becomes 6 mm, and the prepared press sheets are stacked again in the order of configuration, heat-press-formed, and integrated. To make The molded sheet was punched out into a circular shape so as to have a weight of about 3 g.
After being melted by heating with hot air at 30 ° C. for 3 minutes, it was inserted into a mold of a 28 mmφ cap. Immediately, the sample was pressurized and cooled with a pressing die, and the cap was adjusted to a cap shape such that the top surface of the cap was 1.5 mm, thereby producing a sample cap.

<Test Bottle Preparation Method> A 500 ml PET bottle (manufactured by Toyo Seikan) has a carbon dioxide concentration of 50%.
0 ml was filled with 500 ml of 3.5 volume carbon dioxide water at 5 ° C., and using the prepared sample resin cap, tightening the cap was 15 kg-cm.
The test was carried out at a torque of 1.

<Confirmation of Laminated Structure> The sample cap is frozen (-120 ° C. with liquid nitrogen) by an ultramicrotome in a direction perpendicular to the top surface of the sample cap to a thickness of about 0.1 μm. The cut sample was dyed with ruthenium tetroxide to obtain a sample for observation of a laminated structure. The laminated structure of the cap liner or the cap was confirmed for the sample by a transmission electron microscope (acceleration voltage: 200 kV).

<Cap Impact Test> As a test for comparing the impact resistance of the cap, the following test method was carried out.

At 23 ° C., the cap of the test bottle was vertically dropped from a height of 50 cm on a flat iron plate with the cap top side facing downward, and cracks in the cap liner or cap were confirmed. The number of tests was set to 20 and the number of breaks such as cracks was confirmed.

<Carbon dioxide permeation test> JIS K712
According to 6-87 (Method A), a test was performed using a three-piece gas permeation tester manufactured by Toyo Seiki. The shape of the test piece was heated and compressed so that the press-formed body used at the time of preparing the sample cap was 0.4 mm in the case of a cap liner and 1.5 mm in the case of a cap. The center portion was cut into a circle having a diameter of 70 mm to obtain a test piece. Regarding the comparison of the cap liner, the carbon dioxide permeation coefficient of the test piece produced by the configuration of Comparative Example 1 was 1
Regarding the comparison of caps, the carbon dioxide permeation coefficient of the test piece manufactured by the configuration of Comparative Example 4 was set to 100, and the cap was compared with other test pieces.

Example 1 Thermoplastic resin (Ultra-linear low-density polyethylene manufactured by Tosoh Corporation: Lumitac 22-1; melt flow rate (J
IS K7210-76; 190 ° C, 2.16 kg load) 2 g / 10 min, density (JIS K6760-8)
1) 0.900 g / cm ³ , monodispersity 4.2, hereinafter PE
-1), a carbon dioxide low permeable resin (ethylene-vinyl alcohol copolymer manufactured by Kuraray Co., Ltd .: EVAL E)
PG156A; carbon dioxide gas permeability coefficient 2.8 × 10
⁻¹⁸ mol × m / (m ² × s × Pa), hereinafter referred to as EVOH), and the outer layer (PE-1) / the inner layer (EVOH) / the outer layer (PE-1) = 0.25 / 0.2 / 0. A .25 mm sheet molded product for a cap liner was prepared, and a cap with a cap liner was molded by the above-described method to obtain a test bottle. Confirmation of the laminated structure, a cap impact test and a carbon dioxide permeation test were performed, and the test results are shown in Table 1.

Example 2 In Example 1, EVOH-1 was replaced with a carbon dioxide low-permeability resin (polyamide 6: UBE nylon 1011FB manufactured by Ube Industries, Ltd .; carbon dioxide gas permeability coefficient 5.2 × 10 5).
^-18 mol × m / (m ² × s × Pa), hereinafter referred to as PA6), and various tests were performed as in Example 1. Table 1 shows the test results.

Example 3 In Example 1, the structure of the sheet molding was changed to the outer layer (PE-
1) / Inner layer (EVOH) / Outer layer (PE-1) = 0.3 /
Various tests were performed in the same manner as in Example 1 except that the thickness was changed to 0.1 / 0.3 mm. Table 1 shows the test results.

Example 4 In Example 1, the structure of the sheet molding was changed to the outer layer (PE-
1) / Inner layer (EVOH) / Outer layer (PE-1) = 0.32.
/0.06/0.32 mm, and various tests were performed as in Example 1. Table 1 shows the test results.

Example 5 In Example 1, the structure of the sheet molding was changed to the outer layer (PE-
1) / Inner layer (EVOH) / Outer layer (PE-1; PET bottle contact side) = 0.5 / 0.04 / 0.16 mm, and various tests were performed as in Example 1. Table 1 shows the test results.

Example 6 In Example 1, PE-1 was replaced with polyethylene (manufactured by Dow:
PF1140; melt flow rate (JIS K721
0-76; 190 ° C, 2.16 kg load) 2 g / 10 m
in, density (JIS K6760-81) 0.900 g
/ Cm ³ , monodispersity 2.1, hereinafter referred to as PE-2), and various tests were performed as in Example 1. Table 1 shows the test results.

Comparative Example 1 In Example 1, the sheet constituting material was changed to PE-1 0.7
mm, and various tests were performed in the same manner as in Example 1. Table 1 shows the test results.

Comparative Example 2 In Example 1, EVOH-1 was replaced with polypropylene (manufactured by Chisso Corp .: Chissopolypro K1011); melt flow rate (JIS K7210-76; 230 ° C .;
3. 16g load) 0.7g / 10min, monodispersity
7. Carbon dioxide gas transmission coefficient 2.2 × 10 ^-15 mol ×
m / (m ² × s × Pa), hereinafter referred to as PP), and various tests were conducted as in Example 1. Table 1 shows the test results.

Comparative Example 3 In Example 1, the structure of the sheet molding was changed to the outer layer (PE-
1) / Inner layer (EVOH) / Outer layer (PE-1) = 0.15
/0.4/0.15 mm, and various tests were performed as in Example 1. Table 1 shows the test results.

Example 7 Thermoplastic resin (high-density polyethylene manufactured by Tosoh Corporation):
Nipolon Hard 5700; Melt flow rate (JIS
K7210-76; 190 ° C, 2.16 kg load)
1.0 g / 10 min, density (JIS K6760-8
1) 0.953 g / cm3, monodispersity 5.4, hereinafter PE
-3), a carbon dioxide low-permeability resin EVOH, and an outer layer (PE-3) / an inner layer (EVOH) / an outer layer (PE
-3) = A molded sheet for a cap having a size of 2/2/2 mm was prepared, and the cap was molded by the method described above to obtain a test bottle. Confirmation of the laminated structure, a cap impact test and a carbon dioxide permeation test were performed, and the test results are shown in Table 2.

Example 8 In Example 7, various tests were carried out in the same manner as in Example 7 except that EVOH was changed to PA6-1, a low carbon dioxide permeable resin. Table 2 shows the test results.

Example 9 In Example 7, the structure of the sheet molding was changed to the outer layer (PE-
3) / Inner layer (EVOH) / Outer layer (PE-3) = 2.8 /
Various tests were performed in the same manner as in Example 7 except that the thickness was changed to 0.4 / 2.8 mm. Table 2 shows the test results.

Example 10 In Example 7, PE-3 was replaced with high-density polyethylene (Nipolon Hard 5400, manufactured by Tosoh Corporation); melt flow rate (JIS K7210-76; 190 ° C., 2.1
0.85g / 10min, density (JIS)
K6760-81) 0.958 g / cm ³ , monodispersity 7.9, hereinafter referred to as PE-4), and various tests were carried out as in Example 7. Table 2 shows the test results.

Embodiment 11 In Embodiment 7, PE-3 was changed to PP.
Various tests were conducted in the manner described above. Table 2 shows the test results.

Comparative Example 4 In Example 7, the sheet material was changed to PE-36 mm
Various tests were performed according to the procedure of Example 7. Table 2 shows the test results.

Comparative Example 5 In Example 7, EVOH was changed to PP.
Various tests were conducted in the manner described above. Table 2 shows the test results.

Comparative Example 6 In Example 7, the structure of the sheet molding was changed to the outer layer (PE-
3) / Inner layer (EVOH) / Outer layer (PE-3) = 1.2 /
Various tests were performed in the same manner as in Example 7 except that the size was changed to 3.6 / 1.2 mm. Table 2 shows the test results.

[0051]

[Table 1]

[Table 2]

The cap liner and cap of the present invention have a characteristic of low carbon dioxide permeability, which is not found in conventionally known cap liners and caps, and impair the original flavor of the contents of the container for a long period of time. Useful without.

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Claims (19)

[Claims] 1. A thermoplastic resin (a) having a carbon dioxide gas permeability coefficient (JIS K7126-87) of 1.0 × 10 ^-16.
mol × m / (m ² × s × Pa) or less, a laminated body composed of a carbon dioxide low-permeability resin (b), which has a laminated structure in the plane direction and a laminated thickness composition ratio of thermoplastic Resin (a) thickness: carbon dioxide low permeability resin (b) thickness = 100: 0.1 to 100: 100. 2. The cap liner according to claim 1, wherein the thermoplastic resin (a) is a polyolefin resin. 3. The polyolefin resin has a monodispersity (weight average molecular weight / number average molecular weight) in gel permeation chromatography measurement of 1.5 to 3.0. 3. The cap liner according to 2. 4. The method according to claim 1, wherein the carbon dioxide low-permeability resin (b) comprises at least one of an ethylene-vinyl alcohol copolymer, a polyamide resin and a polyester resin. The cap liner as described. 5. The cap liner according to claim 1, wherein the cap liner is used for packaging containers for carbonated beverages. 6. The cap liner according to claim 1, wherein the use of the cap liner is for packaging containers for alcoholic beverages. 7. The method according to claim 1, wherein a laminated sheet of the thermoplastic resin (a) and the carbon dioxide low-permeability resin (b) is punched, melted or semi-melted, and compression molded. A method for producing the cap liner according to the above. 8. The method for producing a cap liner according to claim 7, wherein the compression ratio expressed by the thickness of the cap liner / the thickness of the laminated sheet is 0.10 to 0.99. 9. The multi-layer extruded melt is hot-cut,
2. A compression molding in a molding die.
7. The method for producing a cap liner according to any one of claims 6 to 6. 10. A cap with a cap liner according to claim 1. 11. A thermoplastic resin (a) having a carbon dioxide gas permeability coefficient (JIS K7126-87) of 1.0 × 10
^-16 mol x m / (m ² x s x Pa) or less, composed of a low-permeability carbon dioxide resin (b). Is thermoplastic resin (a) Thickness: carbon dioxide low permeability resin (b)
A cap having a thickness of 100: 0.1 to 100: 100. 12. The cap according to claim 11, wherein the thermoplastic resin (a) is a polyolefin resin. 13. A polyolefin resin having a monodispersity (weight average molecular weight / number average molecular weight) in gel permeation chromatography measurement of from 1.5 to 3.0. 13. The cap according to 12. 14. The method according to claim 11, wherein the carbon dioxide low-permeability resin (b) comprises at least one of an ethylene-vinyl alcohol copolymer, a polyamide resin and a polyester resin. The cap described. 15. The cap according to claim 10, wherein the cap is used for packaging containers for carbonated beverages. 16. The cap according to claim 10, wherein the use of the cap is for packaging containers for alcoholic beverages. 17. A laminated sheet of a thermoplastic resin (a) and a carbon dioxide low-permeability resin (b) is punched, melted or semi-melted, and compression molded.
The method for producing a cap according to any one of the above. 18. The method for producing a cap according to claim 17, wherein a compression ratio represented by a thickness of the cap / a thickness of the laminated sheet is 0.10 to 0.99. 19. The method for producing a cap according to claim 11, wherein the melt extruded from the multilayer is hot-cut and compression molded in a molding die.