JP2642728B2 - Bottle - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a polyethylene naphthalate resin bottle, and more particularly, to a polyethylene naphthalate resin bottle excellent in gas barrier properties and excellent in transparency and heat resistance.

Technical Background of the Invention Conventionally, glass has been widely used as a material for containers such as seasonings, oils, juices, carbonated drinks, beer, sake, cosmetics, and detergents. However, since the production cost of the glass container is high, a method of collecting an empty container after normal use and circulating and reusing the container has been adopted. Further, since the glass container is heavy, the transportation cost is increased, and the glass container is liable to be broken and is inconvenient to handle.

In an effort to overcome these drawbacks of glass containers, the conversion from glass containers to various plastic containers has recently been rapidly progressing. As the material, various plastics are adopted according to the kind of the filling content and the purpose of use. Among these plastic materials, polyethylene terephthalate or polyethylene naphthalate has 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, and cosmetics. Among these uses, hollow molded containers for filling juices, soft drinks, and carbonated drinks are required to be sterilized and filled at a high temperature. Therefore, heat-resistant resins that can withstand high-temperature filling are required. It is required to form a hollow molded container, and all of these hollow molded containers for filling are required to be excellent in shape stability such as transparency and small variation in internal volume. .

However, conventionally known polyethylene terephthalate or polyethylene naphthalate bottles are considerably excellent in gas barrier properties and heat resistance, but the appearance of synthetic resin bottles having further excellent gas barrier properties and heat resistance is desired. ing.

Object of the Invention The present invention has been made in view of the above points, and provides a polyethylene naphthalate bottle having excellent gas barrier properties, and excellent transparency and heat resistance. The purpose is.

SUMMARY OF THE INVENTIONThe bottle according to the present invention is made of polyethylene naphthalate resin, and has a carbon dioxide gas permeability coefficient Pc defined as below of 0.13 cccm / dayatm or less, and defined as follows. The average thickness coefficient tc of the central portion of the body portion excluding the plug portion of the bottle to be manufactured is not more than 0.2.

Pc = P × f [where P is the carbon dioxide permeability of the whole bottle (cc / day · at
m), f = S / V (cm ^-1 ), S is the internal surface area of the drawn bottle (excluding the inner surface of the plug), and V is the internal volume of the drawn bottle (excluding the plug volume). ). Tc = t × f × 10 where t is the average thickness (mm) of the central part of the body part excluding the plug part of the bottle, and f is the same as above. Specific Description of the Invention Hereinafter, the bottle according to the present invention will be specifically described.

In the present invention, polyethylene naphthalate resin is used to form a bottle. This polyethylene naphthalate resin contains ethylene-2,6-naphthalate units derived from 2,6-naphthalenedicarboxylic acid and ethylene glycol in an amount of 60 mol% or more, preferably 80% or more, more preferably 90 mol% or more. It is desirable that the structural unit other than ethylene-2,6-naphthalate be 40
It may be contained in an amount of less than mol%.

Structural units other than ethylene-2,6-naphthalate include terephthalic acid, isophthalic acid, 2,7-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, diphenyl-4,4'-dicarboxylic acid, and 4,4 ' -Diphenyl ether dicarboxylic acid, 4,4'-diphenyl sulfone dicarboxylic acid, 4,4'-diphenoxyethane dicarboxylic acid, aromatic dicarboxylic acid such as dibromoterephthalic acid, adipic acid, azelaic acid, sebacic acid, decane dicarboxylic acid, etc. Aliphatic dicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, cyclopropanedicarboxylic acid, alicyclic dicarboxylic acid such as hexahydroterephthalic acid, glycolic acid,
hydroxycarboxylic acids such as p-hydroxybenzoic acid and p-hydroxyethoxybenzoic acid, propylene glycol, trimethylene glycol, diethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, decamethylene glycol, neopentylene glycol, p
-Xylene glycol, 1,4-cyclohexanedimethanol, bisphenol A, p, p-diphenoxysulfone, 1,4-bis (β-hydroxyethoxy) benzene,
Examples include structural units derived from 2,2-bis (p-β-hydroxyethoxyphenyl) propane, polyalkylene glycol, p-phenylenebis (dimethylsiloxane), glycerin, and the like.

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, for example, in an amount of 2 mol% or less. May be included.

Further, the polyethylene naphthalate resin used in the present invention contains a small amount of a structural unit derived from a monofunctional compound such as benzoyl benzoic acid, diphenyl sulfone monocarboxylic acid, stearic acid, methoxy polyethylene glycol, phenoxy polyethylene glycol, for example, 2 mol%.
It may be contained in the following amounts.

Such polyethylene naphthalate resins are substantially linear, which is confirmed by the dissolution of the polyethylene naphthalate in o-chlorophenol.

The intrinsic viscosity [η] of polyethylene naphthalate measured in o-chlorophenol at 25 ° C. is in the range of 0.2 to 1.1 dl / g, preferably 0.3 to 0.9 dl / g, particularly preferably 0.4 to 0.8 dl / g. Is desirable.

The intrinsic viscosity [η] of polyethylene naphthalate is measured by the following method. That is, polyethylene naphthalate is dissolved in o-chlorophenol at a concentration of 1 g / 100 ml, the solution viscosity is measured using an Ubbelohde capillary viscometer at 25 ° C., and then o-chlorophenol is gradually added. The solution viscosity on the low concentration side is measured, and the intrinsic viscosity ([η]) is obtained by extrapolating to the 0% concentration.

The temperature-rise crystallization temperature (Tc) when the polyethylene naphthalate is heated at a rate of 10 ° C./min with a differential scanning calorimeter (DSC) is 150 ° C. or higher, preferably 160 to 230 ° C.
C, particularly preferably in the range of 170 to 220C.

In addition, the temperature rise crystallization temperature (Tc) of polyethylene naphthalate is measured by the following method. That is, a sample of about 10 mmg from the center of a polyethylene naphthalate chip dried at about 140 ° C. under a pressure of about 5 mmHg for about 5 hours or more using a DSC-2 type differential scanning calorimeter manufactured by Perkin Elmer Co.
Is sealed in a liquid aluminum pan under a nitrogen atmosphere and measured. The measurement conditions were as follows: first, the temperature was rapidly raised from room temperature, melted and held at 290 ° C for 10 minutes, then rapidly cooled to room temperature, and then the peak temperature of the exothermic peak detected when the temperature was raised at a rate of 10 ° C / min. Ask.

The above-mentioned polyethylene naphthalate can be produced by a conventionally known production method.

In the polyethylene naphthalate used in the present invention,
Heat stabilizers, weather stabilizers, antistatic agents, lubricants, release agents,
Various compounding agents such as a pigment dispersant, a pigment or a dye, which are usually used by adding to polyester, can be added within a range not to impair the object of the present invention.

The bottle according to the present invention is made of such a polyethylene naphthalate resin, and has a carbon dioxide gas transmission coefficient Pc defined as below of 0.13 cccm / dayatm or less, preferably 0.12 cccm / dayatm. Below, more preferably 0.10cc
Cm / day · atm or less, and the average thickness coefficient tc of the central portion of the body portion excluding the plug portion of the bottle as defined below is preferably 0.2 or less, more preferably 0.18 or less.

Pc = P × f [where P is the carbon dioxide permeability of the whole bottle (cc / day · at
m), f = S / V'cm ^-1 ), S is the inner surface area of the stretched bottle (excluding the inner surface of the spout), and V is the inner volume of the stretched bottle (excluding the spout volume). ). Tc = t × f × 10 where t is the average thickness (mm) of the central part of the body part excluding the plug part of the bottle, and f is the same as above. The carbon dioxide permeability P (cc / day · atm) of such a polyethylene naphthalate resin bottle is measured as follows. That is, after filling dry ice into a stretched hollow molded bottle at 23 ° C. by adjusting the amount of filling so that the internal pressure becomes about 5 kg / cm ² , the bottle is left in a constant temperature room at 23 ° C. and 50% RH to store the weight of the ice over time. The change was measured, and the average amount of carbon dioxide permeated per day from the 7th to 21st days after the encapsulation (1 atm, the volume of carbon dioxide (cc) converted to 23 ° C.) was calculated as the internal pressure (atm ). The number of test bottles was three for each sample, and the average value was determined.

The internal volume V (excluding the cap portion) of the stretched bottle can be measured by adding water to the portion of the bottle other than the cap portion.

The internal surface area (excluding the inner surface of the spout) S of the stretched bottle is
The bottle can be divided, the inner surface shape is detected by a three-dimensional measuring machine, divided into minute parts, and the measurement can be performed by a minute division method in which the area of the minute parts is integrated. In the case where the stretched bottle has a simple shape, it is also possible to assume that the body of the bottle is a cylinder, assume that the lower and upper portions of the bottle are each a hemisphere, and determine the internal surface area as an approximate value.

The average thickness t (mm) at the center of the body except for the mouth of the bottle is obtained by dividing the center of the bottle into four parts,
It can be obtained by measuring and averaging the thickness (mm) at a point.

The gas barrier property with thickness correction measured for reference was evaluated using commonly used carbon dioxide gas permeability coefficient Pd (CO ₂ ) and oxygen gas permeability coefficient Pd (O ₂ ), and was manufactured by MODERN CONTROL (US ) Carbon dioxide permeation tester PE
Using RMATRARC-IV, the temperature was 23 by the PERMATRAN method.
Cd, relative humidity 0%, carbon dioxide permeability coefficient Pd of a sample consisting of a section at the center of the body of a bottle with a thickness of 300 to 450 μm
(CO ₂ ) and MODERN CONTROL (USA) OXT
Using the RAN100 type, measure the carbon dioxide gas permeability coefficient Pd (O ₂ ) of a sample consisting of a section at the center of the body of a bottle with a thickness of 300 to 400 μm by the OXTRAN method at a temperature of 23 ° C. and a relative humidity of 0%. did.

In such a polyethylene naphthalate resin bottle according to the present invention, the stretching index defined as follows is 130 cm or more, preferably 140 to 220 cm, more preferably 150 cm or more.
It is desirable that the film is highly stretched to 200 cm.

Hereinafter, a bottle according to the present invention will be described with reference to FIG.
As shown in FIG. 1, the bottle 1 according to the present invention includes a plug 2, an upper shoulder 3, a trunk 4, a lower shoulder 5, and a bottom 6.

When such a bottle 1 is manufactured, a preform 7 is used, and the preform 7 is shown by a dotted line in FIG.

The internal volume of the above-described stretched bottle (excluding the cap volume) is, specifically, an internal volume below the support ring 8 of the bottle 1, and more specifically, an internal volume below the virtual straight line 9. Means the volume inside the bottle.

In addition, the internal volume of the unstretched preform (excluding the plug)
Is the internal volume below the support ring 8 of the preform 7, and more specifically, means the internal volume below the virtual straight line 9.

Furthermore, the inner surface area of the stretched bottle (excluding the cap volume)
Is the internal surface area of the stretched bottle below the support ring 8 of the bottle 1, and more specifically, means the internal surface area of the bottle below the virtual straight line 9.

In such a bottle according to the present invention, the wall thickness at the body is the same as that of a conventionally known bottle, and is usually about 0.1 to 0.5, preferably about 0.2 to 0.4 mm.

Next, a method for producing a bottle according to the present invention will be described.

First, a preform is produced from the polyethylene naphthalate resin as described above, and this preform can be produced by a conventionally known method.

Such a preform is manufactured by a conventionally known method, but in the present invention, since the stretched portion of the preform is stretched higher than the conventionally known method, the length of the preform is smaller than that of the conventional preform. It is desirable to be formed shorter than the reform. If necessary, the diameter of the preform can be smaller than that of the conventional preform.

In the present invention, a bottle is manufactured by blow molding the preform for forming a bottle as described above.

At this time, blow molding is performed so that the obtained bottle has a stretch index of 130 cm or more, preferably 140 to 220 cm, and more preferably 150 to 200 cm.

The temperature during blow molding of the preform is 110 to 150
C. Preferably, it is 120 to 150C, more preferably 125 to 145C.

Consisting of the polyethylene naphthalate resin obtained in this way, the stretching index defined as above is 13
A bottle stretched 0 cm or more is extremely excellent in gas barrier properties. For example, the gas barrier property against carbon dioxide (CO ₂ ) is improved by about 20 times as compared with a conventionally commercially available bottle made of polyethylene terephthalate. The gas barrier property against oxygen (O ₂ ) is also improved about 7 times. Furthermore, the bottle according to the present invention has a gas barrier property against carbon dioxide (CO ₂ ) of about 3 times as compared with a bottle made of polyethylene naphthalate resin having a stretch index of about 95 cm as defined herein. The gas barrier property against oxygen (O ₂ ) is also remarkably improved to about twice.

Further, the bottle according to the present invention has heat resistance (Tg is about 120 ° C.)
And also excellent in transparency and mechanical strength.

Effects of the Invention The bottle according to the present invention has a remarkably improved gas barrier property against oxygen or carbon dioxide, and also has excellent heat resistance, transparency, and mechanical strength.

Example 1 A polyethylene naphthalate resin having the following physical properties obtained from 2,6-dinaphthalenedicarboxylic acid and ethylene glycol was used as a molding machine M-10 manufactured by Meiki Seisakusho Co., Ltd.
It was molded at 0A to obtain a preform for forming a bottle. The molding temperature at this time was 270 to 290 ° C.

Polyethylene naphthalate resin: Intrinsic viscosity [η]: 0.6 dl / g Heating crystallization temperature (Tc): 180 ° C. Next, the preform obtained as described above is CORPOP
It was molded with a LAST-01 LB-01 molding machine to obtain a biaxially stretched bottle. The stretching temperature at this time was 130 to 140 ° C.

Unstretched preform inner volume (excluding spout) is 19cm
³ , and the internal volume (excluding the stopper) of the obtained stretched bottle was 1469 cm ³ .

The inner surface area of the stretched bottle (excluding the inner surface of the spout)
It was 678 cm ² .

 Therefore, the stretching index is calculated as follows.

The carbon dioxide permeability P, the carbon dioxide permeability coefficient Pd (CO ₂ ) and the oxygen gas permeability coefficient Pd (O ₂ ) were measured as described in the specification.

 Table 1 shows the results.

Transparency was measured by cutting the body of the bottle and using a haze meter NDH-20D manufactured by Nippon Denshoku Co., Ltd.
The haze of the test piece was measured three times by a method according to 003, and the average value was evaluated.

 Table 1 shows the results.

Comparative Example 1 In Example 1, the unstretched preform having an inner volume of 33.4 cm ³ excluding the plug was used to increase the bottle stretching index to 95.
The procedure was the same as in Example 1 except that cm was used.

 Table 1 shows the results.

Comparative Example 2 The procedure of Example 1 was repeated, except that polyethylene terephthalate was used instead of polyethylene naphthalate.

 Table 1 shows the results.

[Brief description of the drawings]

 FIG. 1 is a schematic explanatory view of a bottle. 1 ... bottle 2 ... stopper 3 ... upper shoulder 4 ... trunk 5 ... lower shoulder 6 ... bottom

Claims (1)

(57) [Claims] 1. A method comprising a polyethylene naphthalate resin,
Carbon dioxide permeability coefficient Pc defined as below is 0.13
A bottle characterized by being not more than cc · cm / day · atm and having an average thickness coefficient tc of not more than 0.2 at the center of the body portion excluding the plug portion defined as follows: Pc = P × f [where P is the carbon dioxide permeability of the whole bottle (cc / day · at
m), f = S / V (cm ^-1 ), S is the internal surface area of the drawn bottle (excluding the inner surface of the plug), and V is the internal volume of the drawn bottle (excluding the plug volume). ). Tc = t × f × 10 where t is the average thickness (mm) of the central part of the body part excluding the plug part of the bottle, and f is the same as above. ]