JPH04173134A - Heat-resistant and sunproof bottle - Google Patents

Abstract

PURPOSE:To contrive to improve the heat resistance and sunproofness by a method wherein the mouth part of a blown bottle is whitened by heat treatment and, further, light-reflecting pigment and light-absorbing pigment are simultaneously added to polyester, which forms the mouth part and the cylindrical part of the bottle. CONSTITUTION:The mouth part 1 and the support ring 5 of a bottle concerned has five-layered structure consisting of three heat-resistant resin layers 9 and two polyester layers 7. Its cylindrical part 3 and its bottom part 4 consist of one pigment-containing polyester layer 7. Further, the mouth part 1 and the support ring 5 are crystallized by heat treatment. In the polyester layer 7, 2.5-6.0 pts.wt. of light-reflecting pigment is added to 100 pts.wt. of polyester. As the light-reflecting pigment, especially rutile titanium white is preferably used. Furthermore, 0.005-0.015 pts.wt. of light-absorbing pigment is added to 100 pts.wt. of the polyester. As the light-absorbing pigment, especially black pigment such as carbon black is preferably used.

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 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 (heat filling), in which polyester bottles are filled with liquid at 80 to 95°C, and batherizing (heat sterilization) using hot showers, have created excellent heat resistance near the mouth of the bottle. It has become required. This is because in hot-filling, the mouth is first exposed to hot liquid, and in hot shower basterizing, the hot shower is generally poured from above the bottle, and the mouth of unstretched polyester is exposed to heat. This is because it will occur.

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

As such an attempt, a method for manufacturing a heat-resistant bottle by co-injecting polyester and a heat-resistant resin layer 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 proposed making the bottle even more layered (Patent Application No. 1999-
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.

It has also been proposed to whiten the mouth by crystallization through heat treatment, thereby imparting heat resistance to the mouth (JP-A-57-201631, JP-A-58-2173).
No. 26, JP-A-59-138417, JP-A-59-3
3101 etc.).

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.

In addition, blow-molded bottles made of resin in which titanium white (Ti02) is dispersed in polystyrene have relatively excellent light-shielding properties and are used in some cases. However, although these bottles have high UV blocking properties, a large amount of visible light passes through them, so the contents tend to deteriorate and the shelf life is not long enough.

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

[Means to solve the problem]

As a result of intensive research in view of the above objectives, the present inventors whitened the mouth of a blow-molded bottle by heat treatment, and further contained a light-reflecting pigment and a light-absorbing pigment simultaneously in the polyester that forms the mouth and body. They discovered that it is possible to achieve excellent heat resistance and light-shielding properties by doing so, and have completed the present invention.

That is, the heat-resistant and light-shielding bottle of the present invention is made of resin and has a mouth, a support IJ song provided at the lower end of the mouth, a shoulder continuing to the support ring, a body and a bottom. The mouth part is whitened by crystallization by heat treatment and has heat resistance, and the resin forming the mouth part and body part is made of polyester based on 100 parts by weight of polyester.
2.5 to 6.0 parts by weight of light-reflecting pigment and 0 parts by weight of light-absorbing pigment
．． 005 to 0.015 parts by weight, and is characterized by having light-shielding properties.

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

Furthermore, in order to further improve the heat resistance of the mouth of the bottle, it is desirable to provide a heat-resistant resin layer on the mouth.

〔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. Moreover, although the bottle 1O may be formed entirely of polyester, it is preferable to have a multilayer structure consisting of a polyester layer 7 and a heat-resistant resin layer 9. That is, in FIG. 1, 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,
The body part 3 and the bottom part 4 consist of one pigment-containing polyester layer 7.

Further, as shown in an enlarged view in FIG. 2, the mouth portion 1 and the support ring 5 are crystallized by a heat treatment described later (dotted portion). Therefore, it is whitened and its heat resistance is further improved.

The multilayer bottle 10 is manufactured by co-injection molding a polyester resin and a heat-resistant resin using the method exemplified in JP-A No. 1-146707, for example, to produce a preform, 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, diphenyldicarboxylic acids, diphenoxychetane 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 fatty acids 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. Group glycols, alicyclic glycols such as cyclohexane dimetatool, 2,2-bis(4'-β-hydroxyethoxyphenyl)propane, other aromatic diols, and the like 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,
Those that have been subjected to a reduced pressure treatment or heat treatment in an inert gas atmosphere at a temperature of 180 to 250°C, or those that have been subjected to solid phase polymerization to reduce the content of low molecular weight polymers such as oligomers and acetaldehyde are suitable.

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 (T102), 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.
In particular, it is preferable to use carbon black, which is a black pigment. The light scattered by the particles of the light-reflecting pigment is absorbed by the particles of the light-absorbing pigment, so that the light does not pass through the resin.

If 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 it is added further, and the color of the resin will change. It darkens and spoils the appearance of the bottle.

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

Furthermore, in the polyester layer of the present invention, iron oxide (generally called red iron oxide) is used to hide the light-absorbing pigment, suppress its color development, and maintain a good color of the bottle.
It is preferable to add 0.05 to 0.1 parts by weight of Fe203). If it is less than 0.05 part by weight, the above effect cannot be obtained, and if it exceeds 0.1 part by weight, coloring 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 resin constituting the heat-resistant resin layer 9 includes polyarylate, polycarbonate, polyethylene naclate, polyacecool, polysulfone, polyetheretherketone, polyethersulfone, polyetherimide, polyphenylene sulfide, and these resins. Blend polymers with polyethylene terephthalate, blend polymers between the above heat-resistant resins, blend polymers with two or more of the above heat-resistant resins and polyethylene terephthalate, U polymer (manufactured by Unitika, blend of polyarylate and polyethylene terephthalate) polymers), polymer alloys of polyarylates and polycarbonates and polyethylene terephthalates, 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.

Crystallization of the mouth part can be performed by heating the mouth part 1 from its surroundings. Specifically, after the preform is molded, the mouth part 1 is cooled and released, and then heated in a separate process (off-line method), or by slowly cooling and keeping warm during the molding and cooling process of the preform. Method of crystallization (inline method)
This can be done either way. In either method, it is preferable to use a heating mold in which a heater is built in a lip mold that grips the mouth portion 1, since the apparatus is not large-scale.

The heating temperature in the offline method needs to be higher than the crystallization temperature of the polyester layer 7, and is particularly preferably higher than the glass transition point and 140 to 210°C. If the heating temperature is less than 160°C, the crystallization process will take too long, and if it exceeds 200°C, air bubbles will be generated due to rapid heating of the polyester layer, causing the shape of the mouth to collapse. The preferred heating temperature is 160-180°C. The heating time is 70 to 150 seconds.

On the other hand, in the in-line method, both the polyester layer and the heat-resistant resin layer are crystallized through a step of slow cooling from a high-temperature molten state, so there is no need to heat the lip mold itself to a high temperature. In this method, the heating temperature that allows slow cooling and heat retention is preferably 90 to 110°C. If the heating temperature is less than 90°C, sufficient crystallization will not occur within the in-line molding cycle (usually 70 to 150 seconds).

If the temperature exceeds 130°C, crystallization of the polyester layer from the mouth to the body will occur, and the part that will become the shoulder after bottle molding will become opaque. The preferred heating temperature is 90-110℃
It is. At this heating temperature, the time required for crystallization is 70 to 150 seconds, which is the same as the above-mentioned in-line molding cycle.

[For production]

In the bottle of the present invention, the mouth part is whitened by crystallization through heat treatment, so the heat resistance of the mouth part is significantly improved.

Moreover, the reason why the bottle of the present invention has sufficient light-shielding properties is considered to be due to the following reasons. That is, as shown in FIG. 3, the incident light is scattered by the light-reflective pigment particles 20 dispersed in the polyester layer 7, and the optical path when passing through the polyester layer 7 becomes significantly longer. Furthermore, since the light-absorbing pigment particles 30 are also present in the polyester layer 7, the scattered light has a high probability of hitting the light-absorbing pigment particles 30 and being absorbed. 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 telescrate resin (Unitika Co., Ltd. N)
B) l-2050>100 M For the lubricant, 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 by weight of alkylene bis fatty acid amide as a lubricant. and 0.16 parts by weight of higher fatty acid salt to prepare a polyester resin.

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.

The mouth of the obtained multilayer preform was heated at 170° C. for 140 seconds using a heating mold with a heater built into the lip mold to effect crystallization.

Next, this preform was subjected to biaxial stretch blow molding to produce a milky white bottle with a substantially uniform wall thickness of about 0.35 mm and a capacity of 900 ml. 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 found that light with a wavelength of 600r+m or less was
% and was confirmed to have excellent light blocking properties.

In addition, the lactic acid beverage was heated and sealed in the bottle, and after being stored for one year, a sensory test was conducted, and the results confirmed that the bottle had a good taste and had a sufficiently long shelf life.

Example 2 and Comparative Examples 1 to 3 5.0 parts by weight of titanium white and 0.01 parts by weight of carbon black were added to 100 parts by weight of polyethylene terephthalate Nit resin (NEH-2050 manufactured by Unitika Co., Ltd.). , a polyester resin was prepared.

This polyester resin was injection molded, and the mouth part of the obtained preform was heated at 170° C. for 140 seconds in the same manner as in Example 1 to effect crystallization. Next, a bottle with a thickness of about 0.35 mm was formed by biaxial stretch blow molding (Example 2
).

For comparison, a commercially available polystyrene colored bottle (about 0.5 mm thick) was used in Comparative Example 1).

Polyethylene terephthalate resin (NEH-2050)
A polyester resin was prepared by adding 2.5 parts by weight of titanium white to 100 parts by weight. Next, using this polyester resin, injection molding and blow molding were performed in the same manner as in Example 2 to form a bottle with a thickness of approximately 0.35 mm (Comparative Example 2).

Polyethylene terephthalate resin (NEH-2050”
) 5.0 parts by weight of titanium white was added to 100 parts by weight to prepare a polyester resin. Next, using this polyester resin, injection molding and blow molding were performed in the same manner as in Example 2 to form a bottle with a thickness of approximately 0.35 mm (Comparative Example 3).

In Comparative Examples 1 to 3, crystallization at the mouth was not performed.

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 800n
Almost no wavelengths of m or less were transmitted, showing excellent light-shielding properties.

〔Effect of the invention〕

As explained above, when light enters the bottle of the present invention,
Particles of light-reflecting pigment in the polyester layer scatter light,
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.

Furthermore, since the mouth part is whitened by crystallization, the heat resistance of the mouth part is significantly improved.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing a bottle according to an embodiment of the present invention, FIG. 2 is an enlarged cross-sectional view of the mouth of the bottle of FIG. 1, and FIG. FIG. 4 is an enlarged sectional view of the polyester layer for explanation, and FIG. 4 is a graph showing the results of measuring the light-shielding property of the bottle using a spectrophotometer. 1... Mouth 2... Shoulder 3... Body 4... Bottom 5... Support ring 7... Polyester layer 9... Heat resistant resin layer 10... Bottle 20. ...Light-reflecting pigment particles 30...Light-absorbing pigment particles

Claims (5)

[Claims] (1) In a resin bottle having a mouth, a support ring provided at the lower end of the mouth, a shoulder following the support ring, a body and a bottom, the mouth is crystallized by heat treatment. It is whitened and has heat resistance,
The resin forming the mouth and body is polyester 1.
00 parts by weight, it contains 2.5 to 6.0 parts by weight of a light-reflecting pigment and 0.005 to 0.015 parts by weight of a light-absorbing pigment, and has a light-shielding property. Heat-resistant and light-shielding bottle. (2) The heat-resistant and light-shielding bottle according to claim 1, wherein the mouth portion has a multilayer structure consisting of a polyester layer and a heat-resistant resin layer. (3) In the heat-resistant and light-shielding bottle according to claim 1 or 2, the resin forming the body further includes 0% iron oxide.
A heat-resistant and light-shielding bottle containing 0.05 to 0.1 parts by weight. (4) The heat-resistant and light-shielding bottle according to any one of claims 1 to 3, wherein the light-reflecting pigment is titanium white. (5) The heat-resistant and light-shielding multilayer bottle according to any one of claims 1 to 4, wherein the light-absorbing pigment is carbon black.