JPH04113836A - Heat-resistant light interrupting multilayer bottle - Google Patents

Abstract

PURPOSE:To obtain a bottle having heat resistance and excellent in light shielding ability by a method wherein the structure of a blow-molded bottle is made up of the multilayer consisting of a polyester layer and a heat resisting resin layer, and light reflecting and absorbing pigments are incorporated in the polyester layer simultaneously. CONSTITUTION:In a bottle 10, a neck part 1 and a support ring 5 have a five- layer structure consisting of a three-layer heat resisting resin layer 9 and a two-layer polyester layer 7 and a body part 2 and a bottom part 4 consist of one-layer pigment-containing polyester layer 7. As the polyester resin constituting the polyester layer 7, a thermoplastic resin consisting of saturated dicarboxylic acid and saturated dihydric alcohol can be used. A light reflecting pigment is added to the polyester resin in an amount of 2.5-6.0 pts.wt. relative to 100 pts.wt. polyester and a light absorbing pigment is also added thereto in an amount of 0.005-0.015 pts.wt. relative to 100 pts.wt. polyester. On the other hand, polyarylate can be used as the resin for the heat resisting resin layer 9.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a resin bottle manufactured by stretch blow molding, and more particularly to a multilayer bottle with excellent heat resistance and light shielding properties.

[Problems to be solved by conventional techniques and inventions] In recent years,
So-called hot fill, in which polyester bottles are filled with liquid at 80 to 95°C, and pastelizing using hot showers have come to be used, and as a result, excellent heat resistance has become required near the mouth of the bottle. This is because in a hot fill, the mouth is first exposed to the hot liquid, and in batherizing with a hot shower, the hot shower is generally poured from the top of the bottle.

Under these circumstances, various attempts have been made to impart heat resistance to polyester bottles.

As an attempt at such a method, a method for producing a heat-resistant bottle by co-injecting polyester and a heat-resistant resin to form a multi-layered preform and stretch-blow molding it was disclosed in JP-A No. 63-19208. has been disclosed. In addition, the applicant has previously improved the co-injection method,
We would like to propose making the bottle even more layered.
No. 163261 and Japanese Patent Application No. 16329 (Hei 2-16329). These multilayer bottles have many heat-resistant resin layers, especially in the mouth, and have good heat resistance.

On the other hand, many beverages 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 manufacture to consumption, it is desirable that the bottle in which they are enclosed has light-shielding properties.

Examples of such light-shielding bottles include bottles made of colored glass, bottles whose bodies are further wrapped in paper, and the like. However, their designs are extremely limited, and many of them are inferior in appearance. In addition, it is heavy, making it inconvenient to handle.

Blow-molded bottles made of polystyrene with titanium white (T102) dispersed therein have relatively good light-shielding properties and are used in some cases. However, although the bottle had a high UV shielding property, a large amount of visible light was transmitted through the bottle, and the t1 contents were easily deteriorated, so the shelf life was not long enough.

Therefore, an object of the present invention is to provide a blow-molded multilayer bottle that has heat resistance and excellent light shielding properties.

[A means of promise to solve problems]

As a result of intensive research in view of the above objectives, the present inventors developed a blow-molded bottle with a multilayer structure consisting of a polyester layer and a heat-resistant resin layer, and further contained a light-reflecting pigment and a light-absorbing pigment in the polyester layer at the same time. They discovered that it is possible to make a material with excellent heat resistance and light shielding properties, and completed the present invention.

That is, the heat-resistant and light-shielding multilayer bottle of the present invention has a mouth, a support ring provided at the lower end of the mouth, a shoulder following the support ring, a body and a bottom, and the mouth has a The polyester layer has a multilayer structure consisting of the polyester layer and the heat-resistant resin layer, and the polyester layer contains 2.5 to 6 parts by weight of a light reflective pigment based on 100 parts by weight of the polyester.
．． 0 parts by weight, and 0.005 to 0.015 parts by weight of a light-absorbing pigment.

When light enters the polyester layer constituting the bottle of the present invention, particles of the light-reflecting pigment scatter the light. Since the scattered light is absorbed by the particles of the light-absorbing pigment, the light does not pass through the resin. In particular, visible light and ultraviolet rays with wavelengths of 780 nm or less are blocked.

It is preferable to use titanium white as the light-reflecting pigment and carbon black as the light-absorbing pigment.

In addition, 0.05 to 0 iron oxide is added to the polyester layer.
, 1 part by weight is preferably added. Adding iron oxide suppresses the color development of light-absorbing pigments, making it possible to maintain a good color of the bottle.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a bottle according to one embodiment of the present invention.

The bottle 10 consists of a mouth part 1, a shoulder part 2, a support ring 5 provided between them, a body part 3, and a bottom part 4. Further, the bottle 10 includes a pigment-containing polyester layer 7,
It has a multilayer structure consisting of a heat-resistant resin layer 9. That is, the mouth part 1 and the support ring 5 have a five-layer structure consisting of three heat-resistant resin layers 9 and two polyester layers 7, and the body part 3 and the bottom part 4 have a one-layer pigment-containing polyester layer 7. Consisting of

The multilayer bottle 10 is manufactured by manufacturing a preform by co-injection molding a polyester resin and a heat-resistant resin, for example, by the method exemplified in JP-A No. 1-146707, and then biaxially stretching and blow molding the preform. Manufactured by. In that case, by changing the number of resin channels in the hot runner nozzle that injects the resin and the timing of starting and stopping co-injection, the number of layers in each part after completion can be changed as appropriate.

As the polyester resin constituting the polyester layer 7, a thermoplastic resin made of a saturated dicarboxylic acid and a saturated dihydric alcohol can be used. As a saturated dicarboxylic acid,
Terephthalic acid, isophthalic acid, phthalic acid, naphthalene
Aromatic dicarboxylic acids such as 1,4- or 2,6-dicarboxylic acid, diphenyl ether-4,4'-dicarboxylic acid, diphenyl dicarboxylic acids, diphenoxyethane diethanedicarboxylic acids, adipic acid, sepatic acid, azelaic acid, decane Aliphatic dicarboxylic acids such as -1,10-dicarboxylic acid, alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, etc. can be used. Saturated dihydric alcohols include aliphatic alcohols 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 cyclohexane dimetatool, 2,2-bis(4'-β-hydroxyethoxyphenyl)propane, other aromatic diols, etc. 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 to 1°5,
Preferably it has a value in the range of 0.55 to 0.85.

Also, such polyesters are produced by melt polymerization,
It is preferable to use one that has been subjected to a reduced pressure treatment or a heat treatment in an inert gas atmosphere at a temperature of 180 to 250°C, or one that has been subjected to face phase polymerization to reduce the content of low molecular weight polymers such as oligomers and acetaldehyde.

2.5 to 6.0 parts by weight of a light-reflecting pigment is added to 100 parts by weight of the above polyester. As the light-reflective pigment, white pigments such as titanium white (Tin.), aluminum powder, mica powder, zinc sulfide, and zinc white are preferable, and it is particularly preferable to use rutile-type titanium white. When light enters the resin, it is scattered by particles of the light-reflective pigment. If it is less than 2.5 parts by weight, a sufficient light scattering effect cannot be obtained, and if it exceeds 6.0 parts by weight, there is no significant improvement in the effect even if more than 6.0 parts by weight is added, 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 above polyester. As the light-absorbing pigment, colored pigments such as carbon black, ceramic black, and bone black are preferable, and it is particularly preferable to use carbon black, which is a black pigment. The light scattered by the particles of light-reflecting pigment is
Light does not pass through the resin because it is absorbed by the light-absorbing pigment particles.

If the amount of the light-absorbing pigment is less than 0.005 parts by weight, a sufficient light absorption effect cannot be obtained, and if it exceeds 0.015 parts by weight, the effect will not be significantly improved even if more than 0.015 parts by weight is added. becomes dark and spoils the appearance of the bottle.

The preferred content of light-absorbing pigment is 0.009 to 0.01
2 parts by weight.

Further, in the polyester layer of the present invention, 0.05 to 0.1 part by weight of iron oxide (Fe2O,), commonly called red iron oxide, is added in order to hide the light-absorbing pigment and suppress its color development. is preferable. If it is less than 0.05 parts by weight, the above effects cannot be obtained, and if it exceeds 0.1 parts by weight, coloration due to iron oxide becomes significant and the appearance of the bottle is impaired. The preferred content of iron oxide is 0.07 to 0.09 parts by weight.

Furthermore, additives such as lubricants, stabilizers, antioxidants, heat deterioration inhibitors, ultraviolet deterioration inhibitors, antistatic agents, antibacterial agents, and other resins may be added to the polyester layer within a range that does not impair the purpose of the present invention. You can add an appropriate amount.

On the other hand, the resins constituting the heat-resistant resin layer 9 include polyarylate, polycarbonate, polyethylene naphthalate, polyacetal, polysulfono, polyetheretherketone, polyethersulfone, polyetherimide, polyphenylene sulfide, and combinations of these resins and polyethylene. A blend polymer with terephthalate, and a blend polymer between the above heat-resistant resins, and a blend polymer between two or more of the above heat-resistant resins and polyethylene terephthalate. U polymer (manufactured by Unitika, a blend polymer of polyarylate and polyethylene terephthalate), Polymer alloys of polyarylate, polycarbonate, polyethylene 1 terephthalate, etc. may be used.

Further, in addition to the polyester layer 7 and the heat-resistant resin layer 9, a layer of resin having excellent gas barrier properties against oxygen, carbon dioxide, etc. may be provided.

[For production]

The reason why the multilayer bottle of the present invention has sufficient light-shielding properties is considered to be due to the following reasons. In other words, the 2nd I! I
As shown in the figure, the incident light is scattered by the particles 20 of the light-reflecting pigment dispersed in the polyester layer 7, and the optical path when passing through the polyester layer 7 becomes significantly longer. Furthermore, since there are also light-absorbing pigment particles 30 in the polyester layer 7, the scattered light hits the light-absorbing pigment particles 30,
The probability of absorption increases. Therefore, even if the amount of light-absorbing pigment is relatively small, the absorbance as a whole can be sufficiently high. Based on this principle, sufficient light-shielding properties can be obtained without using a large amount of light-absorbing pigment.

The present invention will be explained in more detail with reference to the following specific examples.

Example 1 Polyethylene terephthalate resin (Unitika Co., Ltd. N)
EH-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 parts by weight of alkylene bis fatty acid amide as a lubricant. Fatty acid salt 0
．． A polyester resin was prepared by adding 16 parts by weight.

In addition, as a heat-resistant resin, a blend polymer of polyethylene terephthalate and polyarylate (U Polymer 840
0, manufactured by Unitika Co., Ltd.) was prepared.

A preform was molded by co-injection molding using the above polyester resin and heat-resistant resin.

Next, this preform is subjected to biaxial stretch blow molding to obtain approximately 0. The button has an almost uniform wall thickness and a capacity of 9
A 25 ml bottle with a milky white color was produced. The mouth of this bottle had a multilayered structure consisting of five layers, as shown in FIG.

When the light transmittance of the body of this bottle was measured using a spectrophotometer, it was confirmed that it blocked 100% of light with a wavelength of 600 nm or less, and had excellent light-shielding properties.

Furthermore, after heating and filling the bottle with lactic acid beverage and storing it for one year, a sensory test was conducted, and it was confirmed that the bottle had a good taste and had a sufficiently long shelf life.

Example 2 and Comparative Examples 1 to 3 Polyethylene terephthalate resin (N manufactured by Unitika Co., Ltd.)
E) I-2050) A polyester resin was prepared by adding 5.0 parts by weight of titanium white and 0.009 parts by weight of carbon black to 100 parts by weight.

This polyester resin was injection molded and then biaxially stretched blow molded to form a bottle with a thickness of approximately 0.3 mm (
Example 2).

A commercially available bottle made of polystyrene resin added with titanium white and having a thickness of approximately Q, 5 mm was prepared (Comparative Example 1).

Polyethylene terephthalate resin (NEII-2050
) 2.5 parts by weight of titanium white was added to 100 parts by weight to prepare a polyester resin. Next, using this polyester resin, a bottle with a thickness of about 0.3 mm was molded in the same manner as in Example 2 (Comparative Example 2).

Polyethylene terephthalate resin (NEH-2050)
A polyester resin was prepared by adding 5.0 parts by weight of titanium white to 100 parts by weight. Next, using this polyester resin, a bottle having a thickness of about Q and 3 mm was molded in the same manner as in Example 2 (Comparative Example 3).

Using the bottles of Example 2 and Comparative Examples 1 to 3, the light transmittance was measured using a spectrophotometer.

The results are shown in FIG. The bottle of Example 2 is 7801
Almost no wavelengths of 171 or less were transmitted, showing excellent light-shielding properties.

C Effects of the Invention] As explained above, when light enters the multilayer bottle of the present invention, the particles of the light-reflective pigment in the polyester layer scatter the light, and the optical path in the polyester layer becomes longer. Therefore, the probability that the scattered light will be absorbed by the light-absorbing pigment particles increases, and the light-shielding properties of the bottle improve. Therefore, the shelf life of the contents can be significantly extended.

Moreover, if iron oxide is further added to the polyester layer, color development of the light-absorbing pigment can be suppressed, and the color of the bottle can be kept good.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing a bottle according to an embodiment of the present invention, FIG. Grad showing the results of measuring the light-shielding properties of using an absorption photometer...Mouth 2...Shoulder 3...Body 4...Bottom 5...Support ring 7...Polyester layer 9 ... Heat-resistant resin layer 10 ... Bottle 20 ... Particles of light-reflecting pigment 30 ... Particles of light-absorbing pigment.

Claims (4)

[Claims] (1) A heat-resistant, light-shielding multilayer bottle having a polyester layer and a heat-resistant resin layer, including a mouth, a support ring provided at the lower end of the mouth, a shoulder following the support ring, a body, and a bottom. and the mouth part has a multilayer structure consisting of the polyester layer and the heat-resistant resin layer, and the polyester layer contains 2.5 to 6 parts by weight of a light-reflecting pigment based on 100 parts by weight of the polyester. .0 part by weight of a light-absorbing pigment and 0.005 to 0.015 parts by weight of a light-absorbing pigment. (2) In the heat-resistant and light-shielding multilayer bottle according to claim 1, the polyester layer further includes 0.05 to 0.0 iron oxide.
A heat-resistant, light-shielding multilayer bottle containing 1 part by weight. (3) The heat-resistant and light-shielding multilayer bottle according to claim 1 or 2, wherein the light-reflecting pigment is titanium white. (4) The heat-resistant and light-shielding multilayer bottle according to any one of claims 1 to 3, wherein the light-absorbing pigment is carbon black.