JPH0339250A - Multilayer bottle, multilayer preform and production of them - Google Patents

Abstract

PURPOSE:To improve heat resistance and transparency by molding a bottle from a laminate prepared by successively laminating a polyethylene dicarboxylic acid copolymer and a polyethylene terephthalate resin. CONSTITUTION:A polyethylene naphthalate resin, a copolymer resin consisting of ethylene glycol, terephthalic acid and naphthalene dicarboxylic acid and a polyethylene terephthalate resin are laminated in this order to form a preform 7 having a multilayer structure. Subsequently, this preform is heated on the side of the polyethylene naphthalate layer and subjected to high stretching blow molding to mold a multilayer bottle 1 consisting of a mouth plug part 2, an upper shoulder part 3, a body part 4, a lower shoulder part 5 and a bottom part 6. The obtained multilayer bottle is excellent in the gas barrier properties to CO2 and also has good transparency.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a polyester resin bottle having a multilayer structure, a multilayer preform, and a method for producing a multilayer bottle. The present invention relates to a multilayer bottle with excellent properties, a multilayer preform for producing the multilayer bottle, and a method for producing a multilayer bottle using the multilayer preform.

Technical Background of the Invention Glass has been widely used as a material for containers for seasonings, oils, juices, carbonated drinks, beer, Japanese sake, cosmetics, detergents, and the like. However, since glass containers are expensive to manufacture, a method is generally adopted in which empty containers are collected after use and recycled for reuse. In addition, glass containers are heavy, which increases shipping costs, and they also have the disadvantage of being easily damaged and difficult to handle.

In order to eliminate these drawbacks of glass containers, there has recently been a rapid shift from glass containers to various plastic containers. Various plastics are used as materials depending on the type of filling contents and the purpose of use. Among these plastic materials, polyethylene terephthalate and polyethylene naphthalate have excellent mechanical strength, heat resistance, and transparency. Because of its excellent gas barrier properties, it is used as a material for containers for juices, soft drinks, carbonated drinks, seasonings, detergents, cosmetics, etc. Among these uses, blow-molded containers for filling juices, soft drinks, and carbonated drinks are required to be sterilized and filled at high temperatures. For this reason, it is required that the blow-molded containers be made of heat-resistant resin that can withstand high-temperature filling, and all of these blow-molded containers for filling have shapes that are transparent and have small variations in internal volume. It is required to have excellent stability.

However, conventionally known polyethylene naphthalate preforms have superior gas barrier properties when molded into bottles compared to polyethylene terephthalate preforms, but they have a problem in that they are difficult to perform high-stretch molding due to their high softening temperature. was there.

A preform with a two-layer structure of polyethylene terephthalate and polyethylene naphthalate was developed as a preform to solve the above problems and to manufacture bottles that also have good gas barrier properties, transparency, and heat resistance. is possible. However, polyethylene terephthalate and polyethylene naphthalate have a large difference in softening temperature, and when stretched using the conventional method, the two peel off due to the difference in stretchability, making it difficult to obtain a bottle with a good appearance. This was difficult, and the improvement in gas barrier properties was also small due to the separation of the raindrops.

The present inventors conducted extensive studies to solve the above-mentioned problems, and found that (A) polyethylene naphthalate resin,
(B) A copolymer resin of ethylene glycol, terephthalic acid, and naphthalene dicarboxylic acid and (C) a polyethylene terephthalate resin are laminated in this order to form a preform with a multilayer structure, which is highly stretch blow molded. The present inventors have discovered that it is possible to produce a multilayer bottle with excellent properties, heat resistance, and transparency, and have completed the present invention.

Purpose of the Invention The present invention aims to solve the problems associated with the prior art, and provides a multilayer structure that has excellent stretchability, gas barrier properties, transparency, and heat resistance. It is an object of the present invention to provide a polyester resin preform having a polyester resin preform, a multilayer bottle obtained from this preform, and a method for producing a multilayer bottle from the preform.

Summary of the Invention The multilayer bottle according to the present invention comprises (A) a polyethylene naphthalate resin, (B) a copolymer resin of ethylene glycol, terephthalic acid, and naphthalene dicarboxylic acid, and (C) a polyethylene terephthalate resin in this order. It is characterized by being laminated.

Moreover, the multilayer preform according to the present invention includes (A) polyethylene naphthalate resin, (B) ethylene glycol,
It is characterized in that a copolymer resin of terephthalic acid and naphthalene dicarboxylic acid and (C) a polyethylene terephthalate resin are laminated in this order.

The bottle manufacturing method according to the present invention is characterized in that a preform having a multilayer structure as described above is heated and blow-molded from the (A) polyethylene terephthalate side.

DETAILED DESCRIPTION OF THE INVENTION The multilayer preform, multilayer bottle, and method for manufacturing the same according to the present invention will be specifically described below.

The multilayer bottle and multilayer preform according to the present invention are (
It has a multilayer structure in which A) polyethylene naphthalate resin, (B) copolymer resin of ethylene glycol, terephthalic acid, and naphthalene dicarboxylic acid, and (C) polyethylene terephthalate resin are laminated in this order. .

Each resin constituting the multilayer bottle and multilayer preform will be described in detail below.

(A) Polyethylene naphthalate resin In the present invention, polyethylene naphthalate resin is used to form the bottle. This polyethylene naphthalate resin contains ethylene-26-naphthalate units derived from 2,6-naphthalene dicarboxylic acid and ethylene glycol in an amount of 60 mol% or more, preferably 80% or more, more preferably 90 mol% or more. Although preferred, it may contain less than 40 mole percent of units other than ethylene-26-naphthalate.

Constituent units other than ethylene-26-naphthalate include terephthalic acid, isophthalic acid, 2,7-naphthalene dicarboxylic acid, 2,5-naphthalene dicarboxylic acid, diphenyl-4,4'-dicarboxylic acid, and 4.4'-diphenyl ether. Aromatic dicarboxylic acids such as dicarboxylic acid, 4,4'-diphenylsulfone dicarboxylic acid, 4,4'-diphenoxyethane dicarboxylic acid, and dibromoterephthalic acid, and fats such as adipic acid, azelaic acid, sepatic acid, and decanedicarboxylic acid. group dicarboxylic acids, l,4-cyclohexanedicarboxylic acid, cyclopropanedicarboxylic acid, alicyclic dicarboxylic acids such as hexahydroterephthalic acid, hydroxycarboxylic acids such as glycolic acid, p-hydroxybenzoic acid, p-hydroxyethoxybenzoic acid, etc. , propylene glycol, trimethylene glycol, diethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, decamethylene glycol, neopentylene gellicol, p-xylene glycol, 1,4-cyclohexanedimethanol, bisphenol A, LD-di Phenoxysulfone, 1
．． 4-bis(β-hydroxyethoxy)benzene, 2.2
Examples include structural units derived from -bis(pβ-hydroxyethoxyphenyl)propane, polyalkylene glycol, p-phenylenebis(dimethylsiloxane), glycerin, and the like.

Furthermore, the polyethylene naphthalate resin used in the present invention contains a small amount of structural units derived from polyfunctional compounds such as trimesic acid, trimethylolethane, trimethylolpropane, trimethylolmethane, and pentaerythritol in an amount of 2 mol% or less. May contain.

Furthermore, the polyethylene naphthalate resin used in the present invention contains a small amount, for example, 2 mol% or less of a constituent unit derived from a monofunctional compound such as benzoylbenzoic acid, diphenylsulfone monocarboxylic acid, stearic acid, methoxypolyethylene glycol, or phenoxypolyethylene glycol. It may be included in the amount.

Such polyethylene naphthalate resins are substantially linear, which means that the polyethylene naphthalate
- Confirmed by dissolving in chlorophenol.

The intrinsic viscosity [η] of polyethylene naphthalate measured in O-chlorophenol at 25°C is 0.2 to 1. ld
j/g, preferably 0.3 to 0.9 dl/g, particularly preferably 0.4 to 0.8 djF7g.

Note that the intrinsic viscosity [η1] of polyethylene naphthalate is measured by the following method. That is, polyethylene naphthalate to O-chlorophenol, 1 g/1
The solution viscosity was measured using an Ubbelohde capillary viscometer at 25°C, and then O-chlorophenol was gradually added to measure the solution viscosity on the low concentration side. Find the limiting viscosity ([η]) by extrapolating to

Additionally, a polyethylene naphthalate differential scanning calorimeter (
The temperature-raising crystallization temperature (Tc) when the temperature is raised at a rate of 10°C/min with DSC) is usually 150°C or higher, preferably 160 to 230°C, particularly preferably 170 to 22°C.
It is desirable that the temperature is in the range of 0°C.

In addition, the temperature-elevated crystallization temperature (T
c) is measured by the following method. That is, using a PerkinElmer Model DSC-2 differential scanning calorimeter, a thin section of about 10 mm of a sample from the center of a polyethylene naphthalate chip was dried at about 140° C. under a pressure of about 5 m Hπ for about 5 hours or more. Measurement is carried out by enclosing the liquid in an aluminum pan under a nitrogen atmosphere. The measurement conditions are: First, the temperature is rapidly raised from room temperature, melted and held at 290℃ for 10 minutes, then rapidly cooled to room temperature, and then the peak temperature of the exothermic peak detected when the temperature is increased at a rate of 10℃/min. demand.

(B) Copolymer resin of ethylene glycol, terephthalic acid, and naphthalene dicarboxylic acid The copolymer resin used in the present invention is composed of ethylene glycol or its ester-forming derivative, and terephthalic acid or its ester-forming derivative. and 2,6-naphthalene dicarboxylic acid or its ester-forming derivative as raw materials.

2.6-naphthalene dicarboxylic acid or its ester-forming derivative should be used in an amount of 21-5 based on the total amount of dicarboxylic acids.
It is preferably used in an amount of 9 mol%, preferably 30-59 mol%.

Terephthalic acid or its ester-forming derivative is preferably used in an amount of 41 to 79 mol%, preferably 41 to 69 mol%, based on the total amount of dicarboxylic acids.

This terephthalic acid or its ester-forming derivative may contain other dicarboxylic acids as shown below.

Such dicarboxylic acids other than terephthalic acid include:
Specifically, aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, naphthalene dicarboxylic acid, diphenyl dicarboxylic acid, and diphenoxyethane dicarboxylic acid; aliphatic dicarboxylic acids such as adipic acid, sebacic acid, azelaic acid, and decane dicarboxylic acid; Examples include alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid.

Further, glycol components other than ethylene glycol may be contained in an amount of less than 60 mol% based on the total amount of glycol.

Specifically, such glycols other than ethylene glycol include aliphatic glycols such as trimethylene glycol, propylene glycol, tetramethylene glycol, neopentyl glycol, and hexamethylene glycol, ring glycols such as cyclohexanedimethanol, and bisphenol. Hydroquinone, 2.2
Examples include aromatic diols such as -bis(4-β-hydroxyethoxyphenyl)propane.

Moreover, instead of this (B) copolymer resin of ethylene glycol, terephthalic acid, and naphthalene dicarboxylic acid, (A) polyethylene naphthalate resin and (C) polyethylene terephthalate resin described herein may be used. A melt blend of the composition may be used, and other polyester resin components may be further included within the range of the above composition.

(C) Polyethylene terephthalate resin The above-mentioned polyethylene terephthalate resin is produced using terephthalic acid or its ester-forming derivative and ethylene glycol or its ester-forming derivative as raw materials, but the polyethylene terephthalate contains 20 mol% or less. Other dicarboxylic acids and/or other glycols may be copolymerized.

Examples of dicarboxylic acids used in copolymerization other than terephthalic acid include aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, naphthalene dicarboxylic acid, diphenyl dicarboxylic acid, and diphenoxyethane dicarboxylic acid, adipic acid, and sebacic acid. , azelaic acid, aliphatic dicarboxylic acids such as decanedicarboxylic acid, and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid.

Specifically, glycols other than ethylene glycol used for copolymerization include aliphatic glycols such as trimethylene glycol, propylene glycol, tetramethylene glycol, neopentyl glycol, hexamethylene glycol, and dodecamethylene glycol, and cyclohexanedimethanol. alicyclic glycols, bisphenols, hydroquinone, 2,2-bis(4-β-
Examples include aromatic diols such as hydroxyethoxyphenyl)propane.

Such polyethylene terephthalate is a substantially linear polyester formed by arranging the engineered ethylene terephthalate component unit (a) alone or randomly arranging the modified ethylene terephthalate component unit (a) and the dioxyethylene terephthalate component unit (b) to form an ester bond. is formed. The fact that the polyethylene terephthalate is substantially linear is confirmed by dissolving the polyethylene terephthalate in O-chlorophenol.

The above polyethylene naphthalate resin, polyethylene terephthalate resin, and ethylene glycol, terephthalic acid, and naphthalene dicarboxylic acid copolymer resin can be produced by conventionally known production methods.

In addition, various compounding agents such as heat stabilizers, weather stabilizers, antistatic agents, lubricants, mold release agents, pigment dispersants, pigments, and dyes, which are usually added to polyester, are added to these resins in accordance with the present invention. It can be added within a range that does not impair the purpose.

Hereinafter, the multilayer preform according to the present invention will be explained in detail.

The multilayer preform according to the present invention can be manufactured by a conventionally known method using each of the resins described above. A preform having such a multilayer structure can be manufactured by coextruding, for example, resin (A), resin (B), and resin (C). In such a preform, it is preferable that the outer peripheral surface layer is molded from (A) resin, and the (Δ) polyethylene naphthalate layer accounts for 5 to 30%, preferably 5 to 2%, of the total thickness.
0%, more preferably 5-15%, (B
) The copolymer resin layer of ethylene glycol, terephthalic acid, and naphthalene dicarboxylic acid has a thickness of 5 to 20%, preferably 5 to 10%, and (C) the polyethylene terephthalate resin layer has a thickness of 90 to 60%. and preferably 90 to 70%. Furthermore, since this preform is highly stretched and molded into bottles, it is desirable that its length be shorter than that of conventional preforms, and if necessary, the diameter of the preform may also be smaller than that of conventional preforms. Can be molded.

Next, a multilayer stretched bottle according to the present invention will be explained.

The multilayer stretched bottle according to the present invention is not particularly limited in size, but is formed to have a high stretching ratio, and specifically, has a stretching index defined as below of 130ao or more,
Preferably 140 to 200011, more preferably 1
It is desirable that the film be highly stretched to 50 to 200 cm.

The stretching index of the bottle according to the present invention will be explained below with reference to FIG. As shown in FIG. 1, the bottle 1 according to the present invention includes a spout 2, an upper layer 3, a body 4, a lower front portion 5, and a bottom 6.
It consists of

When manufacturing such a bottle 1, the preform 7
This preform 7 is shown in FIG. 1 by a dotted line.

The internal volume of the stretched bottle as described above is the internal volume of the stretched bottle 1 excluding the spout 2, specifically, the internal volume of the bottle 1 below the support ring 8, and more specifically, means the internal volume of the bottle below the virtual straight line 9.

This is the internal volume of the preform 7 excluding
It is the internal volume below the support ring 8 of the preform 7, and more specifically means the internal volume of the bottle below the virtual straight line 9.

Further, the inner surface area of the stretched bottle is the inner surface area of the stretched bottle excluding the spout 2, specifically, the inner surface area of the stretched bottle below the support ring 8 of the bottle 1,
More specifically, it means the inner surface area of the bottle below the virtual straight line 9.

The inner surface area of the stretched bottle (excluding the inner surface of the spout) S is calculated using a micro-division method in which the bottle is divided, the shape of the inner surface is detected by a three-dimensional measuring machine, the area is divided into minute parts, and the areas of these minute parts are integrated. It can be measured by Note that when the stretched bottle has a simple shape, the inner surface area can also be determined as an approximate value by assuming that the body of the bottle is a cylinder, and assuming that the lower and upper parts of the bottle are hemispheres.

The stretching index of the above-mentioned stretched bottle can be determined by calculating the inner surface area of the stretched bottle, the internal volume of the stretched bottle (excluding the volume of the spout), and the internal volume of the unstretched bottle (excluding the volume of the spout). can be calculated. Note that the internal volume of a bottle can be easily measured by filling it with a liquid such as water. Note that the units of f value and stretch index are c!
11-1 and 0.

In such a bottle according to the present invention, the wall thickness at the body is:
Same as conventionally known bottles, usually 0.1 to 0.5+
W is preferably about 0.2 to 0.4 m.

When measuring carbon dioxide gas permeability, after adjusting the amount of dry ice in a stretched blow-molded bottle at 23°C to give an internal pressure of approximately 5 kg/d, the bottle was placed at 23°C with 0% dry ice.
Leave it in a thermostatic room at RH and measure the change in weight over time, and calculate the average carbon dioxide permeation ff1 (carbon dioxide volume converted to 1 atm, 23°C) per mouthful from 7 days to 21 days after sealing.
CC) was calculated by subtracting the internal pressure (alas) immediately after filling the dry ice.

The number of test bottles was three for each sample, and the average value was determined.

The gas barrier property was evaluated based on the value of the carbon dioxide permeability coefficient.

Transparency was measured by cutting the body of the bottle and using a haze meter (ND) l-200 manufactured by Nippon Heavy Industries Ltd.
The haze value (
Haze) was measured three times, and the average value was used for evaluation.

Next, a method for manufacturing a multilayer bottle from a multilayer preform will be described.

A multilayer bottle is manufactured from a preform having a multilayer structure in which (A) polyethylene naphthalate resin, (B) ethylene glycol, terephthalic acid and naphthalene dicarboxylic acid copolymer resin, and (C) polyethylene terephthalate resin are laminated in this order. To do this, heat the preform to the appropriate temperature for stretching, and then use a biaxial stretch blow molding machine (Kohoplast Co., Ltd. Type LB-01).
Blow molding can be performed using.

At this time, it is preferable to heat the preform from the (A) polyethylene naphthalate layer side.

Further, when performing heating, it is preferable to use an infrared ray source as a heat source, and it is also preferable to perform heating intermittently.

By heating from the (A) polyethylene naphthalate side using an infrared ray source as a heat source, a temperature gradient is generated from the (A) polyethylene naphthalate side to the (C) polyethylene terephthalate side, so that good stretching can be achieved. Furthermore, by performing heating intermittently, temperature control becomes easier.

The specific temperature for blow molding the preform is 100 to 1
The temperature is desirably 30°C, preferably 110-130°C, more preferably 120-130°C.

Further, the blowing pressure is preferably 20 to 30 kg/ad.

The highly stretched multilayer bottle obtained by the above method can be stretched more highly than conventional polyethylene naphthalate bottles, and this highly stretched multilayer bottle also has superior gas barrier properties compared to polyethylene terephthalate bottles. Moreover, the transparency is also good.

Effects of the Invention The multilayer bottle obtained from the multilayer preform according to the present invention has better gas barrier properties against carbon dioxide than conventional polyethylene terephthalate bottles, and can be stretched to a higher degree than polyethylene naphthalate bottles. It also has excellent transparency.

EXAMPLES The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples.

Example 1 (A) Polyethylene naphthalate resin was heated to 280°C (
B) A copolymer resin of ethylene glycol, terephthalic acid, and naphthalene dicarboxylic acid and (C) a polyethylene terephthalate resin are respectively put into an extruder at 270°C and melted, and from the outer peripheral surface of the preform (A), (B) ,
(C) Supply the three types to the three-layer die in the order of the layers (
The thickness of A/(B)/(C) is each 0.3m10
．． A three-layer pipe with a total wall thickness of 6 m and consisting of 15.4 m of 3-layer pipes was obtained. At this time, the temperature of the cooling water was 50°C. The outer diameter of the obtained pipe was 22 cm.

Next, this pipe was cut, one end was heated and melted to process the bottom part, and the other end was similarly heated and melted to process the plug part to obtain a multilayer preform with a total length of 70 m and a weight of 23 g. .

This multilayer preform was heated to a stretching temperature of 100°C to 130°C, and
The preform was blow-molded using a blow molding machine (OI) at a blowing pressure of 25 kg/cj to obtain a bottle with a stretch index of 158 cm and a volume of 500 cc.

Regarding this bottle, the transparency and carbon dioxide permeability coefficient as defined in the specification were measured.

The results obtained are shown in Table 1.

Example 2 Thickness configuration of 3-layer pipe (A)/(B)/(C)-
A highly stretched multilayer bottle was obtained in the same manner as in Example 1, except that the bottle was changed to 6m10.61111/4.8M. The transparency and carbon dioxide permeability coefficient of this bottle were measured in the same manner as in Example 1.

The results obtained are shown in Table 1.

Example 3 Thickness configuration of 3-layer pipe is (A)/(B)/CC)=
A highly stretched multilayer bottle was obtained in the same manner as in Example 1, except that the length was changed to 0.9 m/10.6 m/4.5 m. The transparency and carbon dioxide permeability coefficient of this bottle were measured in the same manner as in Example 1.

The results obtained are shown in Table 1.

Comparative Example 1 A highly stretched polyethylene terephthalate bottle was obtained by molding in the same manner as in Example 1 using a 6-thickness pipe made only of polyethylene terephthalate. The transparency and carbon dioxide permeability coefficient of this bottle were measured in the same manner as in Example 1.

The results obtained are shown in Table 1.

[Brief explanation of drawings]

FIG. 1 is a schematic illustration of a bottle. 1...bottle 3...Upper tsuba 5...Lower circumference 2...Spout part 4... Torso 6...bottom

Claims (3)

[Claims] (1) A multilayer structure in which (A) polyethylene naphthalate resin, (B) copolymer resin of ethylene glycol, terephthalic acid, and naphthalene dicarboxylic acid, and (C) polyethylene terephthalate resin are laminated in this order. bottle with. (2) A multilayer structure in which (A) polyethylene naphthalate resin, (B) copolymer resin of ethylene glycol, terephthalic acid, and naphthalene dicarboxylic acid, and (C) polyethylene terephthalate resin are laminated in this order. Preform with. (3) It has a multilayer structure in which (A) polyethylene naphthalate resin, (B) copolymer resin of ethylene glycol, terephthalic acid, and naphthalene dicarboxylic acid, and (C) polyethylene terephthalate resin are laminated in this order. A method for manufacturing a multilayer bottle, which comprises heating a preform from the (A) polyethylene naphthalate layer side to perform high stretch blow molding.