JP3042795B2 - Heat resistant light-shielding barrier multilayer bottle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin bottle manufactured by stretch blow molding, and more particularly to a multilayer bottle excellent in heat resistance, light shielding property and barrier property.

[0002]

2. Description of the Related Art In recent years,
So-called hot filling (heating filling), which fills a polyester bottle with a liquid at 80 to 95 ° C, and pasteurizing (heat sterilization) by a hot shower, will be performed.
Therefore, excellent heat resistance has been required near the mouth of the bottle. This is because the mouth is first exposed to a hot liquid in a hot fill, and it is common to pour the hot shower from above the bottle even in pasteurizing with a hot shower.

[0003] Under such circumstances, various attempts have been made to impart heat resistance to polyester bottles.

As such an attempt, a method of producing a heat-resistant bottle by co-injecting a polyester and a heat-resistant resin to form a multilayered preformed body and subjecting it to stretch blow molding is disclosed in Japanese Patent Application Laid-Open No. Sho 63 (1988) -1988. No. -19208.
The present applicant has previously proposed that the bottles be further multi-layered by improving the co-injection method (Japanese Patent Application Nos. 1-163261 and 2-16329). These multilayer bottles have many heat-resistant resin layers especially at the mouth, and have good heat resistance.

[0005] On the other hand, many drinks such as milk drinks and lactic acid drinks deteriorate when exposed to light for a long time. Therefore, in order to prevent deterioration and guarantee quality during the period from production to consumption, it is desirable that the bottles in which they are sealed have a light-shielding property.

As such a light-shielding bottle, there is, for example, a bottle of colored glass, or a bottle in which paper is further wound around the body of the bottle. However, they are extremely restricted in design and often have poor appearance. In addition, handling is inconvenient because of its heavy weight. In addition, titanium white (TiO 2)
Those produced from a resin in which ₂ ) is dispersed have relatively excellent light-shielding properties and are used in some cases. However, although the bottle has a high light-shielding property with respect to ultraviolet rays, a large amount of visible light is transmitted therethrough, so that the contents are easily deteriorated, and the shelf life is not sufficiently long.

[0007] Further, in the case where contents such as juices susceptible to oxygen, carbonated drinks, and foods that need to maintain freshness are contained, it is necessary to make the bottles excellent in gas barrier properties. . Some contents do not like to be mixed with moisture from the outside world, and a bottle for such contents is required to have a moisture barrier property.

Accordingly, it is an object of the present invention to provide a blow-molded multi-layer bottle having heat resistance and excellent light-shielding properties and barrier properties.

[0009]

Means for Solving the Problems As a result of intensive studies in view of the above object, the present inventor has found that a blow-molded bottle has a multilayer structure comprising a light-shielding resin layer, a heat-resistant resin layer, and a barrier resin layer, We discovered that by making the light-shielding resin layer a polyester that simultaneously contained a light-reflective pigment and a light-absorbing pigment, heat resistance, light-shielding properties, and barrier properties could be imparted to the bottle. Completed the invention.

That is, the heat-resistant and light-shielding multilayer multilayer bottle of the present invention has a mouth, a support ring provided at a lower end of the mouth, a shoulder following the support ring, a body and a bottom, The mouth portion has a light-shielding resin layer and a heat-resistant resin layer, the body has a multilayer structure including a light-shielding resin layer and a barrier resin layer, the light-shielding resin layer,
Light reflective pigment 2.5 to 100 parts by weight of polyester
It is characterized by containing 6.0 parts by weight and 0.005 to 0.015 parts by weight of a light absorbing pigment.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a bottle according to an embodiment of the present invention. The bottle 10 includes a mouth 1, a shoulder 2, a support ring 5 provided therebetween, a body 3, and a bottom 4.
In addition, the bottle 10 includes a light-shielding resin layer 7 and a barrier resin layer 8.
And a heat-resistant resin layer 9. That is, the mouth 1 and the support ring 5 have a five-layer structure including three heat-resistant resin layers 9 and two light-shielding resin layers 7, and the body 3 and the bottom part 4 have two layers of light-shielding properties. It comprises a resin layer 7 and one barrier resin layer 8 sandwiched between them.

As described above, the opening 1 is provided with the heat-resistant resin layer 9 on the surface, and therefore has high heat resistance. The trunk 3 and the bottom 4 have high light-shielding properties and barrier properties. The thickness of the barrier resin layer 8 on the body 3 and the bottom 4 is preferably 5 to 8% of the thickness of the body and the bottom.

The multilayer bottle 10 is disclosed in, for example, Japanese Patent Application Laid-Open No. 1-294025.
The preformed body is manufactured by co-injection molding the light-shielding resin, the heat-resistant resin, and the barrier resin by the method exemplified in the above item, and the preformed body is manufactured by biaxial stretch blow molding. At the time of co-injection molding, the number of layers in each part after completion can be appropriately changed by changing the number of resin flow paths in the hot runner nozzle for injecting the resin and the timing of starting and stopping co-injection. .

For example, in the case of the two-gate co-injection method, FIG.
The core mold 110, the lip mold 111, and the cavity mold 11 shown in FIG.
2, a light-shielding resin and a barrier resin are co-injected from a nozzle 113 into an injection mold having a cavity 120 formed by 2 and the resin is injected into a cavity corresponding to a body portion.
Inflow into 120. On the other hand, the heat-resistant resin is injected from the nozzle 114, and the heat-resistant resin is caused to flow in the radial direction from the gate 115.

The light-shielding resin layer 7 is formed by dispersing light-reflective pigment particles and light-absorbent pigment particles in a polyester resin.

As the polyester resin, a thermoplastic resin comprising a saturated dicarboxylic acid and a saturated dihydric alcohol can be used. As the saturated dicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, naphthalene-1,4- or 2,
Aromatic dicarboxylic acids such as 6-dicarboxylic acid, diphenyl ether-4,4'-dicarboxylic acid, diphenyl dicarboxylic acids, diphenoxyethane diethane dicarboxylic acids, adipic acid, sebacic acid, azelaic acid, decane-1,10-dicarboxylic acid And alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid. Saturated dihydric alcohols include aliphatic glycols such as ethylene glycol, propylene glycol, trimethylene glycol, tetramethylene glycol, diethylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, hexamethylene glycol, dodecamethylene glycol, and neopentyl glycol. Glycols, alicyclic glycols such as cyclohexanedimethanol, 2,2-bis (4'-β-hydroxyethoxyphenyl) propane, and other aromatic diols can be used. A preferred polyester is polyethylene terephthalate consisting of terephthalic acid and ethylene glycol.

The above polyester resin has an intrinsic viscosity of 0.5
~ 1.5, preferably in the range of 0.55-0.85. Also, such polyesters are produced by melt polymerization, 1
Those subjected to a reduced pressure treatment or a heat treatment in an inert gas atmosphere at a temperature of 80 to 250 ° C., or those obtained by solid phase polymerization to reduce the content of oligomers and acetaldehyde, which are low molecular weight polymers, are preferable.

Light reflective pigment is added in an amount of 2.5 to 6.0 parts by weight based on 100 parts by weight of the polyester. As the light-reflecting pigment, white pigments such as titanium white (TiO ₂ ), aluminum powder, mica powder, zinc sulfide, and zinc white are preferable, and it is particularly preferable to use rutile titanium white. When light enters the resin, the light is scattered by the particles of the light-reflective pigment. If the amount is less than 2.5 parts by weight, a sufficient light scattering effect cannot be obtained. If the amount exceeds 6.0 parts by weight, the effect is not remarkably improved, and the moldability of the resin deteriorates. The preferred content of the light reflecting pigment is 4 to 5.3 parts by weight.

Further, 0.005 to 0.015 parts by weight of a light absorbing pigment is further added to 100 parts by weight of the polyester. As the light-absorbing pigment, a colored pigment such as carbon black, ceramic black, and bone black is preferable, and carbon black, which is a black pigment, is particularly preferable. Since the light scattered by the particles of the light-reflective pigment is absorbed by the particles of the light-absorbing pigment, the light does not pass through the resin. If the amount of the light-absorbing pigment is less than 0.005 parts by weight, a sufficient light absorbing effect cannot be obtained.If the amount exceeds 0.015 parts by weight, the effect is not remarkably improved even if added more, and the color of the resin becomes dark and the bottle becomes dark. Appearance is impaired.
The preferred content of the light absorbing pigment is 0.009 to 0.012 parts by weight.

Further, 0.05 to 0.1 parts by weight of iron oxide (Fe ₂ O ₃ ), which is generally referred to as red iron oxide, is added to the light-shielding resin layer 7 in order to conceal the above-mentioned light-absorbing pigment and to suppress its color formation. Is preferred. If the amount is less than 0.05 part by weight, the above effects cannot be obtained. If the amount is more than 0.1 part by weight, coloring by iron oxide becomes remarkable and the appearance of the bottle is impaired. The preferred content of iron oxide is 0.07 to 0.09 parts by weight.

Further, additives such as a lubricant, a stabilizer, an antioxidant, a heat deterioration inhibitor, an ultraviolet light deterioration inhibitor, an antistatic agent and an antibacterial agent are added to the light-shielding resin layer within a range not to impair the object of the present invention. And other resins can be added in appropriate amounts.

Next, the resin constituting the heat-resistant resin layer 9 includes polyarylate, polycarbonate, polyethylene naphthalate, polyacetal, polysulfone, polyetheretherketone, polyethersulfone,
Polyetherimide, polyphenylene sulfide, a blend polymer of these resins with polyethylene terephthalate, a blend polymer of the above-mentioned heat-resistant resin, and a blend polymer of two or more kinds of the above-mentioned heat-resistant resins with polyethylene terephthalate, U A polymer (a blend polymer of polyarylate and polyethylene terephthalate, manufactured by Unitika), a polymer alloy of polyarylate and polycarbonate, and polyethylene terephthalate may be used.

As the barrier resin, those having excellent gas barrier properties such as oxygen and carbon dioxide gas include copolymer polyester resin, polyamide resin, ethylene vinyl alcohol copolymer resin, hynitrile resin, polyacrylonitrile, acrylonitrile and methyl Copolymers of acrylate and butadiene (trade name: Valex), polyvinyl chloride, nylon MXD6 comprising meta-xylylenediamine and adipic acid, polyethylene isophthalate copolymers, various liquid crystal polyesters, and the like. It is particularly preferable to use a copolymerized polyester resin. Specifically, B010 (copolymerized polyester resin manufactured by Mitsui Pet Resin Co., Ltd.), MX nylon (Mitsubishi Gas Chemical Co., Ltd.)
Polyamide resin), XYDAR (manufactured by Dartco), VECTRA (manufactured by Celanese Polyplastics), Econole (manufactured by Sumitomo Chemical), Rodrun (manufactured by Unitika), EPE (manufactured by Mitsubishi Chemical),
X7G (manufactured by Eastman), ULTRAX (manufactured by BASF) and the like. In addition, those excellent in both gas barrier properties and moisture barrier properties include polyethylene terephthalic acid, a polyethylene copolymer (PETG) composed of ethylene glycol and cyclohexane dimethanol, and a blend polymer of an ethylene vinyl alcohol copolymer and the above-mentioned PETG. Blend polymers with polyvinyl alcohol can be used.

Polyolefin, vinyl chloride resin and the like are suitable for making a bottle having excellent moisture proof properties.

[0025]

The multilayer bottle of the present invention has a high heat resistance since the heat resistant resin layer 9 is provided on the surface of the mouth. Further, since the body 3 and the bottom 4 are composed of the light-shielding resin layer 7 and the barrier resin layer 8, the light-shielding property and the barrier property are high.

The reason why the light-shielding resin layer exerts light-shielding properties is considered to be as follows. That is, as shown in FIG. 3, the incident light is scattered by the particles 20 of the light-reflective pigment dispersed in the light-shielding resin layer 7 having a polyester resin as a matrix, The optical path becomes significantly longer. Since the light-absorbing pigment particles 30 are also present in the light-shielding resin layer 7, the scattered light hits the light-absorbing pigment particles 30 and the probability of being absorbed is high. For this reason, even if the amount of the light-absorbing pigment is relatively small, the overall absorbance is sufficiently high. By such a principle, sufficient light-shielding properties can be obtained without using a large amount of light-absorbing pigment.

The present invention will be described in more detail with reference to the following specific examples. Example 1 Polyethylene terephthalate resin (NE made by Unitika Ltd.)
H-2050) 100 parts by weight, 5.29 parts by weight of titanium white, 0.01 parts by weight of carbon black, 0.07 parts by weight of iron oxide, and 0.1 part of alkylene bis fatty acid amide as a lubricant.
1 part by weight and 0.16 parts by weight of a higher fatty acid salt were added to prepare a light-shielding resin. As a heat-resistant resin, a blend polymer of polyethylene terephthalate and polyarylate (U-Polymer 8400, manufactured by Unitika Ltd.) was prepared. Further, a copolymerized polyester resin (B010 manufactured by Mitsui Pet Resin Co., Ltd.) was prepared as a barrier resin.

A preform was formed by co-injection molding using the above light-shielding resin, heat-resistant resin and barrier resin.

Then, the preformed body was subjected to biaxial stretch blow molding to produce a milky white bottle having a substantially uniform thickness of about 0.35 mm and a capacity of 925 ml. As shown in FIG. 1, this bottle had a multilayer structure consisting of five layers at the mouth and three layers at the body.

The light transmittance of the body of the bottle was measured using a spectrophotometer.
It was confirmed that the film was cut by 0% and had excellent light-shielding properties.

The bottle was filled with a lactic acid beverage by heating, sealed, stored for one year, and subjected to a sensory test.
It was found that the taste was good and a sufficiently long shelf life was guaranteed.

[0032]

As described above, when light is incident on the multilayer bottle of the present invention, the light-reflective pigment particles in the light-shielding resin layer occupying most of the body scatter light, and the light-shielding resin layer is scattered. The light path inside is longer. Therefore, the probability that the scattered light is absorbed by the particles of the light-absorbing pigment is increased, and the light-shielding property of the bottle is improved. Therefore, the shelf life of the contents can be significantly lengthened. Further, when iron oxide is further added to the light-shielding resin layer, the coloring of the light-absorbing pigment is suppressed, and the color tone of the bottle can be kept good. Further, a barrier resin layer is also provided on the body, so that the barrier property is high. On the other hand, since the heat-resistant resin layer is provided on the surface of the mouth, it has sufficient heat resistance against hot fill and pasteurizing.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a bottle according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing an example of a two-gate mold used to manufacture a multilayer preform.

FIG. 3 is an enlarged sectional view of a light-shielding resin layer for explaining a light-shielding effect of the bottle of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mouth 2 Shoulder 3 Body 4 Bottom 5 Support ring 7 Light-shielding resin layer 8 Barrier resin layer 9 Heat-resistant resin layer 10 Bottle 20 Light-reflective pigment particles 30 Light-absorbing pigment particles 110 Core type 111 Lip Mold 112 Cavity Mold 113, 114 Nozzle 115 Gate 120 Cavity

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI B32B 27/20 B32B 27/20 A 27/36 27/36 // B29L 22:00

Claims (5)

(57) [Claims] 1. A mouth, a support ring provided at a lower end of the mouth, a shoulder following the support ring, a body and a bottom, wherein the mouth is made of a light-shielding resin layer and a heat-resistant resin layer. A heat-resistant and light-shielding multi-layer bottle comprising a light-shielding resin layer and a barrier resin layer, wherein the light-shielding resin layer is a light-reflective pigment based on 100 parts by weight of polyester. A heat-resistant light-shielding multilayer bottle comprising 2.5 to 6.0 parts by weight and 0.005 to 0.015 parts by weight of a light-absorbing pigment. 2. The heat-resistant light-shielding barrier multilayer bottle according to claim 1, wherein the light-shielding resin layer further comprises iron oxide.
A heat-resistant, light-shielding multilayer bottle containing 0.05 to 0.1 part by weight. 3. The heat-resistant and light-shielding multilayer bottle according to claim 1, wherein the barrier resin layer is made of a copolymerized polyester resin. 4. The heat-resistant and light-shielding multilayer bottle according to claim 1, wherein the light-reflective pigment is titanium white. 5. The heat-resistant and light-shielding multilayer bottle according to claim 1, wherein the light-absorbing pigment is carbon black.