JPS58114922A - Manufacture of preform for heat-resistant polyester bolt - Google Patents

Abstract

PURPOSE:To make possible to prepare a preform capable of being blow molded into a heat-resistant polyester bolt, by subjecting a pipe to heat treatment at a specified temperature for a specified period prior to the preforming thereby resulting in the crystalization. CONSTITUTION:A polyethylene terephthalate or copolymerized polyester consisting mainly of a polyethylene terephthalate is melted, extruded and subjected to vacuum molding, and then it is quenched to obtain the transparent pipe. Prior to the preforming, one end or, if desired, both ends of the resulting are heated at a desired temperature in the range of from 90 to 200 deg.C for from 5 to 200sec so that the one end or both the ends are crystallized. After the one end is preheated in molds to be sealed under pressure to be formed with a bottomed section, it is preheated by a preheater 1 and is worked to have a section engageable with a cap by an outer mold 4 and an inner mold 5 thereby a preform is molded. The polyester bottle obtained from the thus prepared preform is improved in heat resitance, and can be filled with seasoning or the like at high temperatures.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing heat-resistant polyester bottle preforms from pipes.

Polyethylene terephthalate or a copolyester based on it has excellent mechanical properties.

In recent years, it has rapidly begun to be developed as a material for bottles, mainly for food applications, due to its chemical properties, transparency, and hygienic properties.

One of the preferred methods for forming polyester bottles is the pipe method, which consists of the following three steps.

■Pipe molding (melt extrusion of polyester, X-air molding and quenching to form a pipe).

■Preform molding (Process the bottom part of the pipe and the neck part of the pipe so that it is possible to separate the cap.).

■Blow molding (Blow to stretch and orient and mold into a bottle.)

When this polyester bottle is filled with seasonings or beverages at a high temperature of 70°C or higher, the parts that are not stretched and oriented, such as the neck and neck of the bottle, the 1M part, and the bottom, are deformed and the outer twill is damaged. Conventional polyester bottles were generally considered to have one drawback in terms of content light at island temperatures.

In order to impart heat resistance to the polyester bottle and enable high-temperature filling, there is a method of crystallizing the polyester preform by heat-treating the neck or the entire neck of the bottle.・9 For example, Unexamined Japanese Patent Publication No. 55-
This is conventionally known in Japanese Patent No. 79237 and the like.

As a result of intensive research in order to produce heat-resistant polyester by the pipe method, the researchers at Zero Starter and others developed the following five methods.

That is, polyethylene terephthalate or a copolyester mainly composed of polyethylene terephthalate is melt-extruded.

From a transparent pipe obtained by rapid cooling after vacuum forming.

The bottom part is hooked and the neck part is processed to make it possible to hold the cap, and the preform is molded.Blow the preform to make a bottle, with one neck part as the main part per k! When forming into an lt shape, the part that is not stretched or oriented is processed into a pipe according to the heat resistance required for the bottle prior to preform molding.
The object is effectively achieved by heat-treating at 90 to 200° C. for 5 to 200 seconds to crystallize and impart heat resistance.

Per k of carrying out the method of the present invention, polyethylene terephthalate obtained by esterification reaction and polycondensation reaction from prelental acid and ethylene glycol, or mainly polyethylene terephthalate, is used in an amount of 7 tal or less in an amount of 10 molar proportion or less of the total acid component. Acids, inphthalic acid, 7thalene dicarboxylic acid, trimellitic acid, pyromellitic acid, 1: uccinic acid, adipic acid, azelaic acid.

Other acid components such as sebacic acid, p-oxybenzoic acid are used. Or diethylene glycol with less than 10 moles of total alcohol content.

Other alcohol components such as ethylene glycol, 1,2-furopanediol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, cyclohexane dimetatool. Copolymerized polyester with an intrinsic viscosity (phenol/tetrachloroethane fat; 1; a! Measured at 20°C in a copolymer) of 0.7 or more (0.7 or less, ' is difficult to form into a pipe) After melt extrusion at 270 to 300°C and molding in a vacuum chamber, 1. Cool and make the pipe 88.

One end of the resulting pipe (the part that forms the mouth and neck) or must g! Prior to preform molding, both ends (parts that shape the mouth and neck and bottom) according to
@@Ma Heat the pipe at the desired temperature for 5 to 200 seconds to crystallize one or both ends. Preheat one end and directly irradiate it in the mold to form a bottomed part. gm
After preheating with the preheater l shown in fO*, the outer metal as shown in Figure 11iHk! l! 4 and the inner mold 5 to make it possible to add a cap, and make the plate 7 into a one-mum KWI shape. Pottery 9
In the figure, 2#7 is a holding stand, 3 is a crystallized pipe with a bottom end, and 6
is preform.

8 indicates a bottomed part, and 9 indicates a mouth and neck part.

A polyester bottle obtained by plowing a preform subjected to [H] by this method has significantly improved heat resistance compared to a bottle not subjected to crystallization treatment, and can be filled with seasonings, beverages, etc. at high temperatures.

According to the method of this invention, the crystallization of the pipe is performed using one or more methods such as direct heat transfer using heated metal, radiant heat, or indirect heating via a layer of gas such as air. , by heating the pipe to the desired temperature.

Next, the effects of the present invention will be specifically explained with reference to Examples and Reference Examples.

Example 1 25-1 x 124% L (weight f#: 361) made from polyethylene terephthalate with an intrinsic viscosity of ff0.90
A portion forming the mouth and neck of the pipe was treated under the conditions shown in Table 1 to crystallize it. Continue to show off the bottomed part.

A preform was prepared by preheating the mouth and neck to 95°C and then molding the mouth and neck.

After blowing the preform to form a bottle (capacity 1tz), fill it with hot water of 70 to 90°C, count the number of defects (deformation and cap leakage) per bottle, and write in Table 2 IK.
The following results were obtained.

Table 1 Reference 111 Same as Example 1, except that the treatment temperature and treatment time were changed to 1.
After crystallizing the pipe and preparing a preform, the same bottle as in Example 1 was molded.
When the hot water of c was filled, the number of defects per 10 bottles was obtained as shown in Table 2.

The 11# pipe under the conditions of 43 and 4 in Table 2 was expensive to remove from the mold, and could not be produced as a preform that could be blow-molded into a bottle.

It would be interesting to compare the examples and reference examples.

The method of the present invention removes glare ohms from the pipe.

Next, before blow molding into a bottle, one end of the pipe (the part that forms the neck and neck) is cut before preform molding.
Alternatively, by crystallizing both ends (the parts forming the neck and bottom), it is possible to prepare a preform that can be blow molded into a heat-resistant polyester bottle that can be filled at high temperatures.

[Brief explanation of drawings]

The vocal part is a cross-sectional view explaining the method of molding the main body.
A) is an explanatory diagram of preheating the mouth and neck of the mouth and neck crystallized bottomed pipe, and tp> is an explanatory diagram of preform molding this. In the figure, l is the predetermined jI! II! , 2 is a holding stand, 3 is a neck-and-neck crystallization bottomed pipe, 4 is an outer mold, 5 is an inner mold, 7 is a holding stand, 6 is a preform, 8 is a bottomed part, and 9 is a mouth-and-neck part. Patent applicant: Nihon Ester Co., Ltd. Representative: Yuzo Kodama

Claims (1)

[Claims] 1. Melt extrusion of polyethylene terephthalate or a copolyester mainly composed of polyethylene terephthalate. From a transparent pipe obtained by rapid cooling after vacuum forming. Around k, the bottom part is sealed and the neck part is processed to make it possible to attach a cap, and then molded into a preform. When blowing the preform to form a bottle, the parts that are not stretched and oriented are pre-7#-
A heat-resistant polyester characterized by being crystallized by heat treatment at 90 to 200°C for 5 to 200 seconds depending on the desired heat resistance in the form of a pipe prior to molding, thereby imparting heat resistance. Manufacturing method for bottle preforms.