JP2019064025A - Multilayer preform and multilayer container - Google Patents

Abstract

To provide a multilayer container exhibiting an excellent oxygen barrier property while nozzle clogging is prevented at the time of production of a preform, and a multilayer preform used for the production of the multilayer container.SOLUTION: The multilayer preform of the present invention comprises, from inside in this order, a first polyolefin resin layer, a polyamide resin layer containing a cobalt catalyst and a second polyolefin resin layer, in which content of the cobalt catalyst is 70 ppm or more and 400 ppm or less in the polyamide resin layer.SELECTED DRAWING: Figure 1

Description

  The present invention relates to multilayer preforms and multilayer containers.

  Polyester-based resins such as polyethylene terephthalate are excellent in mechanical properties, chemical stability, heat resistance, gas barrier properties, transparency and the like, and are inexpensive, so they are widely used in the production of containers for containing food and drink etc. It is used. Such a container can be produced by blow molding a preform, which can be produced by injection molding of a resin composition.

  The container is required to have various functions depending on the contents to be filled. For example, a function to prevent the quality deterioration of the contents due to oxygen dissolved in the contents and oxygen intruded into the container from the outside, that is, oxygen barrier property is required.

For example, the container which used the polyamide-type resin is proposed by Unexamined-Japanese-Patent No. 2004-460987 (patent document 1) as a container which oxygen barrier property improved.
However, there is room for improvement in the oxygen barrier property, and as a container in which the oxygen gas barrier property is further improved, in JP 2007-308155 A (Patent Document 2), a polyamide resin is used as an intermediate layer; Multilayer containers have been proposed which comprise a barrier layer in combination with ~ 600 ppm transition metal catalyst.

JP 2004-460987 A JP 2007-308155 A

  At present, the present inventors have found that the multilayer container proposed in Patent Document 2 uses a large amount of transition metal catalyst, and the transition metal catalyst is in the nozzle during injection molding of a resin composition for producing a preform. It has been found that there is a possibility that the production efficiency may be reduced. In addition, it has been found that the container has room for improvement from the viewpoint of recyclability and manufacturing cost.

The present invention has been made in view of the above problems, and the problem to be solved is a multilayer container exhibiting high oxygen barrier property while preventing occurrence of nozzle clogging at the time of preparation of a preform, and the multilayer container It is to provide a multilayer preform used for the production of
Another object of the present invention is to provide a multilayer container having high recyclability and capable of being manufactured at lower manufacturing cost, and a multilayer preform used for manufacturing the multilayer container.

  The multilayer preform of the present invention comprises a first polyolefin resin layer, a polyamide resin layer containing a cobalt catalyst, and a second polyolefin resin layer from the inside in this order, and cobalt in the polyamide resin layer It is characterized in that the content of the catalyst is 70 ppm or more and 400 ppm or less.

  In one embodiment, the content of the cobalt catalyst in the polyamide resin layer included in the multilayer preform of the present invention is 100 ppm or more and 300 ppm or less.

  In one embodiment, in the multilayer preform, the ratio of the thickness of the polyamide resin layer to the sum of the thicknesses of the first polyester resin layer and the second polyester resin layer is 1/20 or more, 1 / 5 or less.

  The multilayer container of the present invention is characterized by being a blow-molded article of the multilayer preform.

  In one embodiment, the thickness of the 1st polyester system resin layer with which a multilayer container is provided is 50 micrometers or more and 250 micrometers or less.

  In one embodiment, the thickness of the polyamide resin layer included in the multilayer container is 2 μm or more and 50 μm or less.

According to the present invention, it is possible to prevent clogging of the transition metal catalyst in the nozzle during injection molding of the resin composition for producing the multilayer preform while maintaining the oxygen barrier properties of the multilayer container. .
Further, according to the present invention, the recyclability of the multilayer container can be improved, and the manufacturing cost can be reduced.

FIG. 1 is a partial vertical cross-sectional view of a multilayer preform produced by the method of the present invention. FIG. 2 is a schematic view of an injection molding apparatus used by the method of the present invention. FIG. 3 is a schematic view of an injection molding apparatus used by the method of the present invention. FIG. 4 is a partial vertical cross-sectional view of a multilayer container produced by the method of the present invention. FIG. 5 is a partial vertical cross-sectional view of a multilayer container produced by the method of the present invention. FIG. 6 is a front view of the bottom of a multilayer container manufactured by the method of the present invention. FIG. 7 is a schematic view showing a method of manufacturing a multilayer container.

(Multilayer preform)
In one embodiment, as shown in FIG. 1, the multilayer preform 10 of the present invention comprises a mouth 11, a body 12 connected to the mouth 11, and a bottom 13 connected to the body 12. ing.
The multilayer preform 10 according to the present invention at least includes the first polyester resin layer 14, the polyamide resin layer 15, and the second polyester resin layer 16 from the inside in this order.
In addition, the multilayer preform of the present invention may be provided with two or more polyamide resin layers (not shown).

Further, the ratio of the thickness of the polyamide resin layer to the sum of the thicknesses of the first polyester resin layer and the second polyester resin layer (thickness of polyamide resin layer / first polyester resin layer, and It is preferable that it is 1/20 or more and 1/5 or less, and, as for the sum of the thickness of a 2nd polyester resin layer, it is more preferable that it is 1/10 or more and 1/5 or less.
By using the ratio of the thickness of the polyamide-based resin layer to the sum of the thicknesses of the first polyester-based resin layer and the second polyester-based resin layer in the above numerical range, it is manufactured using the multilayer preform of the present invention While being able to improve the recyclability of the multi-layered container, it is possible to prevent the drop of the polyamide-based resin layer during blow molding and the reduction of the oxygen barrier property of the multi-layered container.

(Polyester resin layer)
The multilayer preform of the present invention comprises two or more polyester resin layers, at least a first polyester resin layer and a second polyester resin layer.
The polyester-based resin layers provided in the multilayer preform may have different configurations, or may have the same configuration. Also, the thickness may be different or identical.

In the present invention, a polyester-based resin refers to a resin obtained by condensation polymerization of a polyvalent carboxylic acid and a polyvalent alcohol.
Examples of polyvalent carboxylic acids include terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, zebacic acid, decanedicarboxylic acid, azelaic acid, dodecadicarboxylic acid, cyclohexanedicarboxylic acid and the like. . Moreover, as polyhydric alcohols, for example, ethylene glycol, propanediol, butanediol, pentanediol, hexanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, decanediol, 2-ethyl-butyl-1-propanediol And bisphenol A, diethylene glycol, triethylene glycol, polyethylene glycol and the like.
Among these, polyethylene terephthalate, which is a polymer of terephthalic acid and ethylene glycol, is particularly preferable from the viewpoint of mechanical strength, cost and the like.
In the present invention, as the polyester resin, an acid-modified polyolefin resin obtained by modifying the polyester resin with an unsaturated carboxylic acid such as (meth) acrylic acid, maleic acid, maleic anhydride, fumaric acid or itaconic acid is used. included.
The polyester resin layer may contain two or more polyester resins.

  The content of the polyester resin in the polyester resin layer is preferably 50% by mass or more and 99% by mass or less, and more preferably 60% by mass or more and 95% by mass or less. By making content of polyester-type resin into the said numerical range, the mechanical strength of the multilayer container produced using the multilayer preform of this invention can be improved.

In condensation polymerization of polyvalent carboxylic acid and polyvalent alcohol, catalysts such as titanium catalyst, zirconium catalyst, antimony catalyst, cerium catalyst, germanium catalyst, zinc catalyst and the like can be used.
Among them, a germanium catalyst is preferable from the viewpoint of heat resistance and no elution at high temperature, and an antimony catalyst is preferable from the viewpoint of low cost.

  Insofar as the properties of the present invention are not impaired, the polyester resin layer may be a resin other than polyester resin, for example, polyolefin resins such as polyethylene, polypropylene and polymethylpentene, polyvinyl chloride, polyvinyl alcohol, polyvinyl acetate, hydrochloric acid Vinyl-vinyl acetate copolymers, vinyl resins such as polyvinyl butyral and polyvinyl pyrrolidone, (meth) acrylic resins such as polyacrylates, polymethacrylates and polymethyl methacrylates, polyimides such as polyimides and polyetherimides, A styrene resin, cellophane, cellulose acetate such as cellulose acetate, nitrocellulose, cellulose acetate propionate and cellulose acetate butyrate can be included.

  In addition, the polyester resin layer may contain various additives as long as the characteristics of the present invention are not impaired. For example, plasticizers, ultraviolet light stabilizers, anti-coloring agents, matting agents, deodorants And flame retardants, weathering agents, antistatic agents, yarn friction reducing agents, slip agents, releasing agents, antioxidants, ion exchange agents, dispersing agents, ultraviolet absorbers, and colorants such as pigments and dyes.

The thickness of the first polyester resin layer in the multilayer preform is preferably 800 μm or more and 1800 μm or less, and more preferably 1000 μm or more and 1600 μm or less. By setting the thickness of the first polyester resin layer to the above numerical range, the mechanical strength of the multilayer container produced using the multilayer preform of the present invention can be maintained, and a polyamide resin layer and The distance to the contents can be made appropriate, and the oxygen barrier property of the multilayer container can be improved.
The thickness of the second polyester resin layer in the multilayer preform is preferably 1000 μm or more and 2000 μm or less, and more preferably 1200 μm or more and 2000 μm or less. By setting the thickness of the second polyester resin layer in the above numerical range, the mechanical strength of the multilayer container produced using the multilayer preform of the present invention can be improved.

(Polyamide resin)
The polyamide resin layer included in the multilayer preform of the present invention contains a polyamide resin and a cobalt catalyst. By providing the polyamide-based resin layer, the multilayer preform can improve the oxygen barrier properties of a multilayer container produced using the multilayer preform of the present invention.

Examples of polyamide resins include polymethaxylylene adipamide (nylon MXD6), polyundecaneamide, polydodecane amide, polyhexamethylene sebacamide, polyhexamethylene dodecamide, polyundecamethylene adipamide, polydeca Methylene sebacamide, polydecamethylene dodecamide, polydodecamethylene sebacamide, polydodecamethylene dodecamide, trimethylhexamethylene terephthalamide, polyhexamethylene terephthalamide, poly 2-methylpentamethylene terephthalamide, poly nona methylene terephthalamide , Poly 2-methyloctamethylene terephthalamide, polyhexamethylene isophthalamide, polyhexamethylene cyclohexane dicarboxamide, poly 2-methylpentamethylene cyclohexane Carboxamide, polynonamethylenecyclohexanedicarboxamide, poly 2-methyloctamethylenecyclohexanedicarboxamide, polybis (4-aminocyclohexyl) methandodecamide, polybis (3-methyl-aminocyclohexyl) methandodecamide, polydecamethylene terephthalamide, poly Undecamethylene terephthalamide, polydodecamethylene terephthalamide, polydecamethylene cyclohexane dicarboxamide, polyundecamethylene cyclohexane dicarboxamide, polydodecamethylene cyclohexane dicarboxamide and the like can be mentioned.
Among these, polymetaxylylene adipamide is particularly preferable from the viewpoint of the oxygen barrier property.
The polyamide resin layer may contain two or more polyamide resins.

  The content of the polyamide resin in the polyamide resin layer is preferably 50% by mass or more and 99% by mass or less, and more preferably 60% by mass or more and 95% by mass or less. By making content of the polyamide-type resin in a polyamide-type resin layer into the said numerical range, the oxygen barrier property of the multilayer container produced using the multilayer preform of this invention can be improved more.

The polyamide resin layer contains a cobalt catalyst. Examples of cobalt catalysts include cobalt organic acid salts, halides, phosphates, phosphites, hypophosphites, nitrates, sulfates, oxides, hydroxides, and complexes with β diketones, etc. It can be mentioned. Examples of organic acids include stearic acid, acetic acid, propionic acid, lauric acid, dimethyldithiocarbamic acid, palmitic acid, 2-ethylhexanoic acid, neodecanoic acid, linoleic acid, tallic acid, oleic acid, capric acid, naphthenic acid and the like. .
Among these, an organic acid salt of cobalt is preferable, and cobalt stearate is particularly preferable because the oxygen barrier property of a multilayer container produced using the multilayer preform of the present invention can be further improved.

The content of the cobalt catalyst in the polyamide resin layer is 70 ppm or more and 400 ppm or less.
The content of the cobalt catalyst is more preferably 70 ppm or more and 300 ppm or less, and still more preferably 70 ppm or more and 200 ppm or less. By setting the content of the cobalt catalyst in the above numerical range, the occurrence of nozzle clogging at the time of producing the preform is made more remarkable while maintaining the oxygen barrier property of the multilayer container produced using the multilayer preform of the present invention. It can be prevented. Furthermore, the recyclability of the multilayer container can be further improved, and the manufacturing cost can be further reduced.

  Insofar as the properties of the present invention are not impaired, the polyamide resin layer may be a polyester resin, a polyolefin resin such as polyethylene, polypropylene, and polymethylpentene, polyvinyl chloride, polyvinyl alcohol, polyvinyl acetate, and vinyl chloride-vinyl acetate copolyester. Polymers, vinyl resins such as polyvinyl butyral and polyvinyl pyrrolidone, (meth) acrylic resins such as polyacrylates, polymethacrylates and polymethyl methacrylates, polyimides such as polyimide and polyetherimide, styrene resins, cellophane And cellulose resins such as cellulose acetate, nitrocellulose, cellulose acetate propionate and cellulose acetate butyrate.

  The polyamide resin layer may contain various additives as long as the characteristics of the present invention are not impaired. For example, plasticizers, ultraviolet light stabilizers, anti-coloring agents, matting agents, deodorants And flame retardants, weathering agents, antistatic agents, yarn friction reducing agents, slip agents, releasing agents, antioxidants, ion exchange agents, dispersing agents, ultraviolet absorbers, and colorants such as pigments and dyes.

  The thickness of the polyamide resin layer is preferably 90 μm or more and 300 μm or less, and more preferably 100 μm or more and 200 μm or less. By setting the thickness of the polyamide resin layer to the above numerical range, it is possible to improve the recyclability and the oxygen barrier property of the multilayer container produced using the multilayer preform of the present invention.

(Method of manufacturing multilayer preform)
In one embodiment, the method for producing a multilayer preform of the present invention comprises the steps of heating and melting a resin composition constituting a first polyester resin layer, a polyamide resin layer, and a second polyester resin layer; Injecting the molten resin composition into a mold.

In one embodiment, a multi-layer preform can use the injection molding apparatus 20 shown in FIG.
The injection molding apparatus 20 comprises an injection mold 21 and a core mold 22, between which are formed cavities 23 corresponding to the shape of the multilayer preform.
The injection molding apparatus 20 includes a gate 24 at a position corresponding to the bottom of the multilayer preform of the injection mold 21, and the gate 24 and the injection machines 25 and 26 are connected via a nozzle 27.
The injection machines 25, 26 provided in the injection molding apparatus 20 include a barrel 28 and a screw 29 disposed inside the barrel 28.

(Heating and melting process)
The method of the present invention includes the step of heating and melting the resin composition constituting the first polyester resin layer, the polyamide resin layer, and the second polyester resin layer.
The heating and melting step is usually performed in an injection machine provided in an injection molding apparatus, and at least a resin composition containing a polyester resin and a resin composition containing a polyamide resin and a titanium catalyst are used as the resin composition. Be done.

(Injection process)
As shown in FIG. 3, a resin composition 30 constituting a first polyester resin layer and a second polyester resin layer melted in a barrel 28 and a resin composition 31 constituting a polyamide resin layer are The multilayer preform of the present invention can be produced by advancing the screw 29 and injecting it into the cavity 23 formed by the injection mold 21 and the core mold 22 and molding it.
In addition, in FIG. 3, although the 1st polyester-type resin layer and the 2nd polyester-type resin layer showed the example comprised with the same resin composition, it is not limited to this, Another A barrel may be further provided, and the first polyester resin layer or the second polyester resin layer may be formed of a resin composition having a different structure.

(Multilayer container)
The multilayer container 40 of the present invention is a blow-molded article of the above-mentioned preform, and in one embodiment, as shown in FIG. 4, the mouth 41, the neck 42 provided below the mouth 41, and the neck 42 downward. And a body 44 provided below the shoulder 43, and a bottom 45 provided below the body 44.
Moreover, when heating a container after filling of the contents, it is preferable that the multilayer container 40 has the panel part 46 dented in a container inward as shown in FIG. 4 in the trunk | drum 44 of each side.
Further, as shown in FIG. 4, the multilayer container 40 preferably has a transverse rib 47 extending in the circumferential direction below the body portion 44. Thereby, the strength of the body 44 can be improved.

Although the shape of the bottom of the container 10 is not particularly limited, for example, when the content is a carbonated beverage such as natural foaming water (sparkling water), it is preferable to have a petaloid shape as shown in FIG. Thereby, the deformation of the multilayer container can be prevented when the internal pressure is high.
In one embodiment, in order to prevent deformation of the multilayer container, the bottom 45 of the multilayer preferably has a reinforcing groove 48 as shown in FIG. The number of reinforcing grooves 48 is preferably 5 or more and 12 or less, and more preferably 5 or more and 7 or less. Also, from the viewpoint of pressure dispersion, the number of reinforcing grooves is preferably an odd number.

The thickness of the first polyester resin layer in the multilayer container is preferably 40 μm or more and 230 μm or less, and more preferably 65 μm or more and 190 μm or less. The mechanical strength of the multilayer container can be maintained, the distance between the polyamide resin layer and the contents can be made appropriate, and the oxygen barrier property of the multilayer container can be further improved.
The thickness of the second polyester resin layer in the multilayer container is preferably 50 μm or more and 250 μm or less, and more preferably 75 μm or more and 200 μm or less. The mechanical strength of the multilayer container can be improved by setting the thickness of the second polyester resin layer in the above numerical range.
The thickness of the polyamide resin layer in the multilayer container is preferably 2 μm or more and 50 μm or less, and more preferably 4 μm or more and 50 μm or less. By setting the thickness of the polyamide-based resin layer in the above numerical range, the oxygen gas barrier property of the multilayer container can be improved, and a multilayer container with high recyclability can be obtained.

Moreover, the multilayer container of this invention may be equipped with the vapor deposition film in the inner surface (not shown). By providing the vapor deposition film in the multilayer container, the gas barrier property can be further improved. From the viewpoint of gas barrier properties and transparency, it is preferable to use an inorganic oxide. As such an inorganic oxide, aluminum oxide, silicon oxide, magnesium oxide, calcium oxide, zirconium oxide, titanium oxide, titanium oxide, boron oxide, hafnium oxide, barium oxide and the like can be used.
As a method of forming a deposited film, for example, physical vapor deposition (Physical Vapor Deposition, PVD) such as vacuum deposition, sputtering, and ion plating, or plasma chemical vapor deposition, thermochemical Examples thereof include a chemical vapor deposition method such as a vapor phase growth method and a photochemical vapor deposition method (Chemical Vapor Deposition method, CVD method).

(Method of manufacturing multi-layered container)
The method for producing a multilayer container of the present invention is
Heating the multilayer preform,
Blow molding the multilayer preform in a blow mold.

(Heating process)
The heating of the multilayer preform can be performed by a heating device 51 utilizing near infrared rays, warm air, microwaves, etc. (see FIG. 7a).
The heating temperature of the multilayer preform is preferably 90 ° C. or more and 130 ° C. or less, and more preferably 100 ° C. or more and 120 ° C. or less.

(Blow molding process)
The method of the present invention comprises the step of blow molding the heated multilayer preform in a blow mold.
In one embodiment, as shown in FIG. 7B, the blow molding die 50 is composed of a pair of barrel molds 50a and 50b and a bottom mold 50c which are divided from each other. The pair of body molds 50a and 50b is open to each other, and the bottom mold 50c is raised upward. In this state, the multilayer preform 10 is inserted between the pair of body molds 50a and 50b.

Next, the bottom mold 50c is lowered and the pair of barrel molds 50a and 50b is closed, and the blow molding mold 50 sealed by the pair of barrel molds 50a and 50b and the bottom mold 50c is configured. .
Next, a rod is inserted from the mouth of the multilayer preform 10 so as to contact the bottom of the inner surface of the preform (not shown), and air is pressed into the multilayer preform 10, and the multilayer preform 10 is The biaxial stretch blow molding is carried out to manufacture a multilayer container 40 (see FIG. 7 (c)).
Finally, as shown in FIG. 7D, the multilayer container 40 is taken out from the pair of body molds 50a and 50b and the bottom mold 50c.

  EXAMPLES The present invention will be more specifically described by way of examples, but the present invention is not limited by these examples.

Example 1
The multi-layer molding shown in FIG. 1, which comprises a first polyester resin layer, a polyamide resin layer and a second polyester resin layer from the inside in this order using the injection molding apparatus shown in FIG. A reform was made.
As polyester resin which comprises the 1st and 2nd polyester resin layer, it used with PET, and as a polyamide resin which comprises a polyamide resin layer, МXD6 was used. Moreover, cobalt stearate was used as a transition metal catalyst, and the content of cobalt in the polyamide resin layer was 300 ppm.
In the multilayer preform, the thickness of the polyamide resin layer is 1200 μm, the thickness of the first polyester resin layer is 1600 μm, and the thickness of the second polyester resin layer is 400 μm (the thickness of the polyamide resin layer, Ratio with the sum of thicknesses of the first polyester resin layer and the second polyester resin layer = 1/7).
Although 72 multilayer preforms were continuously produced, nozzle clogging did not occur.

  The multilayer preform obtained as described above was heated to 100 ° C. using an infrared heater, and was conveyed to the blow molding die represented in FIG. 7 (b). In this blow molding die, the multilayer preform was blow molded to obtain a multilayer container having a full filling volume of 520 mL, as shown in FIG. The thickness of the polyamide resin layer in the multilayer container was 30 μm, the thickness of the first polyester resin layer was 100 μm, and the thickness of the second polyester resin layer was 150 μm.

Comparative Example 1
A multilayer preform and a multilayer container were produced in the same manner as in Example 1 except that the content of the cobalt catalyst in the polyamide resin layer was changed to 50 ppm. Further, in the same manner as in Example 1, 72 continuous multilayer preforms were produced, but no nozzle clogging occurred.

Comparative example 2
A multilayer preform and a multilayer container were produced in the same manner as in Example 1 except that the content of the cobalt catalyst in the polyamide resin layer was changed to 500 ppm. Further, in the same manner as in Example 1, 72 continuous multilayer preforms were produced, and nozzle clogging occurred 4 times.

<< Oxygen barrier test >>
The multilayer containers obtained in the above Examples and Comparative Examples were each filled with 500 mL of wine, capped, and stored at 22 ° C. for 1 month. After storage, the rate of reduction of the amount of oxygen in the wine was measured. The measurement results are summarized in Table 1.

10: multilayer preform, 11: mouth, 12: body, 13: bottom, 14: first polyester resin layer, 15: polyamide resin layer, 16: second polyester resin layer, 20: injection Molding apparatus, 21: injection mold, 22: core mold, 23: cavity, 24: gate, 25, 26: injection machine, 27: nozzle, 28: barrel, 29: screw, 30, 31: resin composition, 40: multi-layered container 41: mouth 42: neck 43: shoulder 44 44: body 45: bottom 46: panel 47 47: transverse rib 50: blow molding mold 50a 50b: body Part mold, 50c: Bottom part mold, 51: Heating device

Claims (6)

A first polyolefin resin layer,
A polyamide resin layer containing a cobalt catalyst,
A second polyolefin resin layer from the inside in this order,
Content of the cobalt catalyst in the said polyamide-type resin layer is 70 ppm or more and 400 ppm or less, The multilayer preform characterized by the above-mentioned.   The multilayer preform according to claim 1, wherein a content of the cobalt catalyst in the polyamide resin layer is 100 ppm or more and 300 ppm or less.   The ratio of the thickness of the polyamide resin layer to the sum of the thicknesses of the first polyester resin layer and the second polyester resin layer is 1/20 or more and 1/5 or less. Multilayer preform as described in 1 or 2.   The multilayer container which is a blow molded article of the multilayer preform as described in any one of Claims 1-3.   The multilayer container according to claim 4, wherein the thickness of the first polyester resin layer included in the multilayer container is 50 μm or more and 250 μm or less.   The multilayer container according to claim 4 or 5, wherein the thickness of the polyamide resin layer included in the multilayer container is 2 μm or more and 50 μm or less.