JP7037739B2 - Containers and preforms for making the containers - Google Patents

Description

The present invention relates to a container and a preform for making the container.
More specifically, the present invention relates to a container having excellent gas barrier properties and light-shielding properties, and a preform used for producing the container.

Conventionally, as one of the packaging containers for filling and packaging various articles, a plastic container obtained by injection molding a resin such as polyethylene terephthalate and blow molding the obtained preform is known. These plastic containers have advantages such as light weight, resistance to breakage, low cost, easy manufacturing, and mass production as compared with glass containers, and are widely used as packaging containers.

These plastic containers are required to have various functions depending on the contents to be filled. For example, when the content is deteriorated by oxygen, visible light, or the like, the container is required to have gas barrier property such as carbon dioxide barrier property and oxygen barrier property, and light shielding property.

As a container having an improved gas barrier property and a light-shielding property, a container having a vapor-filmed film formed on the inside and outside by aluminum, aluminum oxide, or the like has been proposed.

However, such vapor deposition film formation can be performed only on the container after blow molding, and cannot be performed on the preform before blow molding. Therefore, it has to be transported in the state of a container, which has led to an increase in cost.

As a container capable of reducing such a transport cost, Japanese Patent Application Laid-Open No. 2003-334906 (Patent Document 1) describes an ethylene-vinyl alcohol copolymer, nylon 6, nylon 6,6, and polymethoxylen adipa. A plastic multilayer container including a gas barrier resin such as mid and a gas barrier layer containing a transition metal catalyst as an intermediate layer has been proposed. However, there was room for improvement in its gas barrier properties.

Further, Japanese Patent Application Laid-Open No. 2015-174662 (Patent Document 2) proposes a container provided with a printing layer and enhanced in light-shielding property. However, there is a problem that the ink contained in the print layer falls off over time and the light-shielding property cannot be exhibited for a long period of time.

Japanese Patent Application Laid-Open No. 2003-334906 Japanese Unexamined Patent Publication No. 2015-174662

Now, the present inventors have formed voids around the fiber material in the container obtained by blow molding a preform containing the fiber material in the resin material as a constituent material, whereby the gas barrier property of the container is formed. And the surprising finding that the light blocking effect is significantly improved.

Therefore, an object of the present invention is to provide a container exhibiting excellent gas barrier property and light shielding property.

Another object of the present invention is to provide a preform used for making the above-mentioned container.

The container of the present invention contains a fiber material and a resin material, and is characterized in that voids are formed around the fiber material.

In one embodiment, the average fiber length of the fiber material contained in the container is 10 μm or more and 300 μm or less.

In one embodiment, the average fiber diameter of the fiber material contained in the container is 100 nm or more and 12 μm or less.

In one embodiment, the container comprises a fiber material and a resin material and has a multilayer structure including a layer in which voids are formed around the fiber material, and the content of the fiber material in the layer is 1% by mass or more. It is 10% by mass or less.

In one embodiment, the container has a multilayer structure composed of a polyester resin layer / a polyamide resin layer / a polyester resin layer, and the polyester resin layer and the polyamide resin layer contain a fiber material.

In one embodiment, the content of the fiber material in the polyester-based resin layer and the polyamide-based resin layer provided in the container is 1% by mass or more and 10% by mass or less.

In one embodiment, the container is a biaxially stretched blow molded product.

In one embodiment, the total light transmittance of the container is 55% or less.

In one embodiment, the haze value of the container is 85% or more and 100% or less.

The preform of the present invention is used for producing the above-mentioned container, and is characterized by having an infrared transmittance of 50% or more.

According to the preform according to the present invention, it is possible to provide a container having excellent gas barrier property and light shielding property.

FIG. 1 is a schematic view showing a process of forming voids in a container. FIG. 2 is a partial vertical cross-sectional view of the container in one embodiment. FIG. 3 is a partial vertical cross-sectional view of the container in one embodiment. FIG. 4 is a partial vertical sectional view of the preform in one embodiment. FIG. 5 is a partial vertical sectional view of the preform in one embodiment. FIG. 6 is an optical micrograph of the container surface obtained in Example 2-3. FIG. 7 is an optical micrograph of the cross section of the container obtained in Example 2-3.

(container)
The container according to the present invention comprises a fiber material and a resin material, and is characterized in that voids are formed around the fiber material.

The average fiber length of the fiber material contained in the container according to the present invention is preferably 10 μm or more and 300 μm or less, and the average fiber diameter is preferably 100 nm or more and 12 μm or less.
By setting the average fiber length and the average fiber diameter of the fiber material within the above numerical ranges, the gas barrier property and the light shielding property of the container can be improved.
In addition, the infrared transmittance of the preform used for producing the container according to the present invention can be improved.
The average fiber length of the fiber material is more preferably 30 μm or more and 150 μm or less, and further preferably 50 μm or more and 100 μm or less.
The average fiber diameter of the fiber material is more preferably 300 nm or more and 10 μm or less, and further preferably 1 μm or more and 5 μm or less.
The average fiber diameter and average fiber length of the fiber material were measured by observing the fiber material with a scanning electron microscope (SEM) and measuring from the scale of the image (n = 10).
If the fiber material has a major axis and a minor axis, the major axis is defined as the fiber length.

Examples of the fiber material include glass fiber, cellulose fiber, carbon fiber, metal oxide fiber, and synthetic resin fiber.
Among these, glass fiber and carbon fiber are preferable, and glass fiber is particularly preferable, because the gas barrier property and the light-shielding property of the obtained container can be further improved and the heat resistance thereof can also be improved.
The preform according to the invention can include two or more fiber materials.

As the glass fiber, conventionally known glass fiber can be used, and for example, E glass, C glass, A glass, S glass, D glass, NE glass, T glass, quartz glass and the like can be used.

The cellulose fiber is not particularly limited as long as it is formed of, for example, a polysaccharide having a β-1,4-glucan structure, and is a plant-derived cellulose fiber, an animal-derived cellulose fiber, a bacterial-derived cellulose fiber, or a synthetic fiber. Any of the cellulose fibers may be used.
Examples of the synthetic cellulose fiber include cellulose acetate, cellulose propionate, cellulose butyrate, cellulose acetate propionate, cellulose acetate butyrate, cellulose nitrate, cellulose sulfate, cellulose phosphate, carboxymethyl cellulose and the like.

Examples of carbon fibers include single-walled carbon nanotubes, double-walled carbon nanotubes, multi-walled carbon nanotubes, carbon nanohorns, carbon nanocoils, cup-stacked carbon nanotubes, vapor-phase grown carbon fibers, and graphite fiber materials.

Examples of the metal oxide fiber include SiO ₂ , ZnO, TiO ₂ , Al ₂ O ₃ , ZrO ₂ , and the like.

Examples of the synthetic resin fiber include a resin fiber made of polyethylene, an ethylene / vinyl acetate copolymer, a polyolefin resin such as polypropylene, a polyester resin, a vinyl resin and the like.

As will be described later, the container according to the present invention may have a single-layer structure or a multi-layer structure, but when it has a single-layer structure, the content of the fiber material is 1% by mass or more. It is preferably 10% by mass or less, and more preferably 3% by mass or more and 7% by mass or less.
When the container according to the present invention has a multi-layer structure, the content of the fiber material in the layer containing the fiber material and the resin material is preferably 1% by mass or more and 10% by mass or less, preferably 3% by mass or more. It is more preferably 7% by mass or less.
By setting the content of the fiber material in the above numerical range, the formation of voids can be satisfactorily performed, and the gas barrier property and the light-shielding property of the container can be further improved. Moreover, the heat resistance can be improved.
When the container according to the present invention has a multi-layer structure, two or more layers may contain a fiber material and a resin material, whereby the gas barrier property and the light-shielding property of the container can be further improved.

Examples of the resin material include polyamide resins such as metaxylene adipamide (MXD6), nylon 6, nylon 6,6, nylon 6 / nylon 6,6 copolymer, polyethylene terephthalate (PET), and polybutylene terephthalate (PBT). , Polyethylene naphthalate (PEN), Polyester terephthalate-isophthalate copolymers and polyester resins such as terephthalic acid-cyclohexanedimethanol-ethylene glycol copolymers, polyethylene (PE), polypropylene (PP) and polymethylpentene, etc. Polymer resins such as polyolefin resins, cellophane, cellulose acetate, nitrocellulose, cellulose acetate propionate (CAP) and cellulose acetate butyrate (CAB), polyvinyl chloride, polyvinyl acetate, polyvinyl alcohol (PVA), ethylene. -Vinyl-based resins such as vinyl acetate copolymer (EVA), ethylene-vinyl alcohol copolymer (EVOH), polyvinylidene chloride copolymer (PVDC) and the like can be mentioned.
Among these, polyamide-based resins are preferable from the viewpoint of gas barrier properties of the container. Further, from the viewpoint of heat resistance and durability, PET and PP are preferable.
The container according to the present invention can contain two or more of the above resin materials.

When the container according to the present invention has a single-layer structure, the content of the resin material is preferably 60% by mass or more and 90% by mass or less, and more preferably 70% by mass or more and 87% by mass or less. ..
When the container according to the present invention has a multi-layer structure, the content of the resin material in the layer containing the fiber material and the resin material is preferably 60% by mass or more and 90% by mass or less, preferably 70% by mass or more. It is more preferably 87% by mass or less.
By setting the content of the resin material in the above numerical range, the gas barrier property and the light-shielding property of the container can be further improved.

When the container according to the present invention contains a polyamide-based resin, it is preferable that the container further contains an inorganic acid salt containing a transition metal-based catalyst or a complex salt of an organic acid salt. Thereby, the gas barrier property of the container can be further improved.
Examples of the metal component of the transition metal catalyst include iron, cobalt, nickel, copper, silver, titanium, zirconium, chromium, manganese and the like.
The transition metal catalyst is used in the form of an inorganic acid salt, an organic acid salt or a complex salt of the above metal components.
Examples of the inorganic acid salt include chloride halides, oxidates, silicates and the like.
Examples of the organic acid salt include propionate, butane salt, hexane salt, stearate, oxalate and the like.
Examples of the complex salt include a complex with β-diton or β-keto acid ester.

The content of the transition metal catalyst in the container is preferably 50 ppm or more and 600 ppm or less, and more preferably 200 ppm or more and 500 ppm or less in terms of the weight ratio of the metal.

The container of the present invention is characterized in that voids are formed around the fiber material.
The void 3 is formed by blowing the preform containing the fiber material 1 and the resin material 2 and peeling the resin material 2 around the fiber material 1 from the fiber material 1 (see FIG. 1).
It is considered that the container of the present invention appears cloudy due to the voids, thereby improving the light-shielding property.

When the container according to the present invention has a single-layer structure, the porosity is preferably 3% or more and 20% or less, and more preferably 5% or more and 15% or less.
When the container according to the present invention has a multi-layer structure, the porosity in the layer in which the voids are formed is preferably 3% or more and 20% or less, and more preferably 5% or more and 15% or less. ..

The haze value of the cloudy container is preferably 85% or more and 100% or less, and more preferably 95% or more and 100% or less. By setting the haze value of the container within the above numerical range, the light-shielding property of the container can be further improved.
In the present invention, the haze value of the container can be measured by a haze meter.

As long as the characteristics of the present invention are not impaired, the container according to the present invention may contain various additives, for example, a plasticizer, an ultraviolet stabilizer, a color inhibitor, a matting agent, a deodorant, and a difficulty. Examples thereof include fuel agents, weather resistant agents, antistatic agents, thread friction reducing agents, slipping agents, mold release agents, antioxidants, ion exchangers, dispersants, ultraviolet absorbers, and colorants such as pigments and dyes.

The shape of the container according to the present invention is not particularly limited, and as shown in FIGS. 2 and 3, the container 10 may have a mouth portion 11, a neck portion 12, a shoulder portion 13, a body portion 14, and a bottom portion 15. ..
Further, the shape of the bottom portion is not particularly limited, and may be, for example, a round bottom shape or a petaloid shape depending on the contents to be filled.

In one embodiment, the container 10 according to the invention has a single layer structure as shown in FIG. Further, in one embodiment, the container 10 according to the present invention has a multi-layer structure as shown in FIG.
As a specific example of the multi-layer structure,
(1) A three-layer structure composed of a polyester resin layer containing a polyester resin such as PET, a polyamide resin layer containing a polyamide resin such as MXD6 and a fiber material, and a polyester resin layer.
(2) A three-layer structure composed of a polyester resin layer containing a fiber material, a polyamide resin layer, and a polyester resin layer containing a fiber material.
(3) Examples thereof include a three-layer structure including a polyester-based resin layer containing a fiber material, a polyamide-based resin layer containing a fiber material, and a polyester-based resin layer containing a fiber material.
Although the preform having three layers is shown in FIG. 3, the preform having a multi-layer structure is not limited to this, and includes the case of two layers, four layers, five layers and the like.

The container according to the present invention is a preform blow-molded product described later, and the blow molding may be uniaxially stretched blow molded or biaxially stretched blow molded, but it is more likely to generate voids and has a light-shielding property. The container according to the present invention is preferably a biaxially stretched blow-molded product.

When the container has a single-layer structure, the thickness of the container is preferably 100 μm or more and 500 μm or less, and preferably 150 μm or more and 300 μm or less.
When the container has a multi-layer structure, for example, a three-layer structure of a polyester resin layer / a polyamide resin layer / a polyester resin layer, the thickness of the polyester resin layer is preferably 70 μm or more and 300 μm or less. , 100 μm or more, more preferably 250 μm or less. The thickness of the polyamide resin layer is preferably 10 μm or more and 100 μm or less, and more preferably 30 μm or more and 80 μm or less.

(preform)
The preform according to the present invention is used for producing the above-mentioned container, and is characterized by having an infrared transmittance of 50% or more. Further, the infrared transmittance is more preferably 65% or more.
When the infrared transmittance of the preform is 50% or more, heating by infrared rays can be satisfactorily performed at the time of blow molding. The infrared transmittance of the preform can be adjusted by the type of fiber material used for producing the preform, the average fiber length, the average fiber diameter, the content, the type of resin material, and the like.
In the present invention, the infrared ray means a light ray having a wavelength of 800 nm to 2500 nm. Further, for example, the infrared transmittance of 50% or more means that the entire range of the infrared wavelength region (800 nm to 2500 nm) is measured when the absorbance of the preform is measured using, for example, a known spectrophotometer. It means that the transmittance is 50% or more.

The preform can be produced by injection molding the above-mentioned resin material or the like using a conventionally known injection molding machine. The shape of the preform is not particularly limited, and may be the shape shown in FIGS. 4 and 5.

The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Example 1-1
A mixture containing PET and glass fiber A (manufactured by Nitto Boseki Co., Ltd., trade name: SS 05DE-413SP, fiber length: 70 μm, fiber diameter: 7 μm) was injection-molded by an injection molding machine to prepare a preform. The content of glass fiber A in the preform was 3% by mass.

When the infrared transmittance of the preform obtained as described above was specified using a spectrophotometer, it was 84%.

The preform obtained as described above is heated to 110 ° C. by an infrared irradiation heating device, and then biaxially stretched and blow-molded in a molding die to have a shape shown in FIG. 2, a capacity of 500 mL. A container with a thickness of 20 μm was prepared. When the surface of the obtained container was observed with an optical microscope, voids were observed around the glass fiber A. Moreover, when the haze value of the obtained container was measured by the haze meter, it was 95.7%.

Example 1-2
Preforms and containers were prepared in the same manner as in Example 1 except that the content of glass fiber A was changed to 5% by mass. The infrared transmittance of the preform was 84%. When the surface of the obtained container was observed with an optical microscope, voids were observed around the glass fiber A. Moreover, when the haze value of the obtained container was measured, it was 98.8%.

Example 1-3
Preform and preform and the same as in Example 1 except that the glass fiber A was changed to the glass fiber B (manufactured by Nitto Boseki Co., Ltd., trade name: SS 10C-404, fiber length: 300 μm, fiber diameter: 11 μm). A container was made. The infrared transmittance of the preform was 84%. When the surface of the obtained container was observed with an optical microscope, voids were observed around the glass fiber B. Moreover, when the haze value of the obtained container was measured, it was 90.3%.

Comparative Example 1-1
A container was prepared in the same manner as in Example 1-1 except that the glass fiber was not used.

Example 2-1
A preform having a multilayer structure composed of a polyester resin layer / a polyamide resin layer containing glass fiber A / a polyester resin layer by co-injection molding a mixture containing PET, MXD6 and glass fiber A, and PET. Was produced.
The content of the glass fiber A in the polyamide resin layer was 5% by mass. The infrared transmittance of the preform was 86%.

The preform obtained as described above is heated to 110 ° C. by an infrared irradiation heating device, and then biaxially stretched and blow-molded in a molding die to have a shape shown in FIG. 3, a capacity of 500 mL. A container having a three-layer structure was produced. The thickness of the polyester-based resin layer was 130 μm, and the thickness of the polyamide-based resin layer containing the glass fiber A was 50 μm. When the surface of the obtained container was observed with an optical microscope, voids were observed around the glass fiber A. Moreover, when the haze value of the obtained container was measured by the haze meter, it was 27.4%.

Example 2-2
A mixture containing PET and glass fiber A, MXD6, and a mixture containing PET and glass fiber A are co-injection molded, and a polyester resin layer containing glass fiber A / a polyamide resin layer / polyester containing glass fiber A is formed. A preform having a multilayer structure composed of a based resin layer was produced. The content of the glass fiber A in the polyester resin layer was 5% by mass in both cases. The infrared transmittance of the preform was 84%.

The preform obtained as described above is heated to 110 ° C. by an infrared irradiation heating device, and then biaxially stretched and blow-molded in a molding die to have a shape shown in FIG. 3, a capacity of 500 mL. A container having a three-layer structure was produced. The thickness of the polyester-based resin layer was 130 μm, and the thickness of the polyamide-based resin layer was 50 μm. When the surface of the obtained container was observed with an optical microscope, voids were observed around the glass fiber A. Moreover, when the haze value of the obtained container was measured by the haze meter, it was 98.2%.

Example 2-3
A mixture containing PET and glass fiber A, a mixture containing MXD6 and glass fiber A, and a mixture containing PET and glass fiber A are co-injection molded to obtain a polyester resin layer / glass fiber A containing glass fiber A. A preform having a multilayer structure composed of a polyamide-based resin layer containing the same and a polyester-based resin layer containing the glass fiber A was prepared. The content of the glass fiber A in each layer was 5% by mass. The infrared transmittance of the preform was 84%.

The preform obtained as described above is heated to 110 ° C. by an infrared irradiation heating device, and then biaxially stretched and blow-molded in a molding die to have a full-fill capacity having the shape shown in FIG. A 500 mL, three-layered container was prepared. The thickness of the layer made of the mixture of polyethylene terephthalate and the glass fiber A was 130 μm, and the thickness of the layer made of the mixture containing MXD6 and the glass fiber A was 50 μm.
When the surface of the obtained container was observed with an optical microscope, voids were observed around the glass fiber A as shown in FIG.
Moreover, when the cross section of the container was observed with an optical microscope, as shown in FIG. 7, voids were observed around the glass fiber A. Moreover, when the haze value of the obtained container was measured by the haze meter, it was 98.2%.

Comparative Example 2-1
A container was prepared in the same manner as in Example 2-1 except that the glass fiber was not used.

Comparative Example 2-2
A mixture containing polyethylene terephthalate and crystal nucleating agent A (manufactured by ADEKA Corporation, trade name: NA-05), a mixture containing MXD6, and a mixture containing polyethylene terephthalate and crystal nucleating agent A were co-injection molded. A preform having a multi-layer structure was produced. The content of the crystal nucleating agent A was 0.02% by mass.

The preform obtained as described above is heated to 110 ° C. by an infrared irradiation heating device, and then biaxially stretched and blow-molded in a molding die to have a full-fill capacity having the shape shown in FIG. A 500 mL, three-layered container was prepared. The thickness of the layer made of a mixture of polyethylene terephthalate and the crystal nucleating agent A was 130 μm, and the thickness of the layer made of MXD6 was 50 μm.

Comparative Example 2-3
Preforms and containers were prepared in the same manner as in Comparative Example 2-2, except that the content of the crystal nucleating agent A was changed to 0.05% by mass.

<< Light-shielding test >>
The light-shielding properties of the containers obtained in the above Examples and Comparative Examples were measured using a spectrophotometer in accordance with JIS K-7361-1 “Plastic-Transparent Material Total Light Transmittance Test Method”. , Evaluated according to the following evaluation criteria. The evaluation results are summarized in Tables 1 and 2.
◯: The total light transmittance was 50% or less.
Δ: The total light transmittance was 51% or more and 55% or less.
X: The total light transmittance was 56% or more.

<< Oxygen barrier test >>
An oxygen permeation test of the containers obtained in the above Examples and Comparative Examples was performed using an oxygen permeation tester (manufactured by MOCON, trade name: OXTRAN). The oxygen permeation test was performed in an environment of 22 ° C. and a humidity of 40% RH. The results were as shown in Tables 1 and 2.

<< Carbon dioxide barrier test >>
The containers obtained in Examples 1-1 to 1-3 and Comparative Example 1-1 were filled with 4.0 GV (gas volume) carbonated water so that the head space was 20 mL, and then capped. 22 It was left for 6 weeks in an environment of ° C. and humidity of 40% RH. The GV of carbonated water after 6 weeks was measured using Direct GV-1 (trade name) manufactured by Biscle Co., Ltd., and the reduction rate of GV was determined. The results were as shown in Table 1.
Further, for Examples 2-1 to 2-3 and Comparative Examples 2-1 to 2-3, the GV reduction rate after being left for 3 weeks, 6 weeks, and 12 weeks was obtained by the same method. It is summarized in Table 2.

<< Heat resistance test >>
The containers obtained in the above Examples and Comparative Examples were left in an environment of 85 ° C. for 10 minutes. Then, the shrinkage amount (mL) of the container was measured. The results were as shown in Tables 1 and 2.

1: Fiber material 2: Resin material 3: Void 10: Container 11: Mouth 12: Neck 13: Shoulder 14: Body 15: Bottom 20: Preform

Claims (9)

A container containing fiber and resin materials,
It has a multi-layer structure consisting of a polyester-based resin layer / polyamide-based resin layer / polyester-based resin layer.
Each layer of the polyester-based resin layer / polyamide-based resin layer / polyester-based resin layer contains the fiber material.
A container, characterized in that voids are formed around the fiber material. The container according to claim 1, wherein the average fiber length of the fiber material is 10 μm or more and 300 μm or less. The container according to claim 1 or 2, wherein the average fiber diameter of the fiber material is 100 nm or more and 12 μm or less. The container according to any one of claims 1 to 3, wherein the content of the fiber material in the polyester resin layer or the polyamide resin layer is 1% by mass or more and 10% by mass or less. The container according to claim 4, wherein the content of the fiber material in each layer of the polyester resin layer / polyamide resin layer / polyester resin layer is 1% by mass or more and 10% by mass or less. The container according to any one of claims 1 to 5, which is a biaxially stretched blow molded product. The container according to any one of claims 1 to 6, wherein the total light transmittance is 55% or less. The container according to any one of claims 1 to 7, wherein the haze value is 85% or more and 100% or less. A preform used for producing the container according to any one of claims 1 to 8.
A preform characterized by an infrared transmittance of 50% or more.

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