JPH06305001A - Polyester hollow molded form - Google Patents

Abstract

PURPOSE:To obtain a hollow molded form having excellent heat resistance and transparency by specifying a composition ratio, mixture melting temgerature of polymer mixture and haze after injection molding and orientation. CONSTITUTION:A polyester hollow molded form has a ratio of ethylene terephthalate unit to carbonate unit of 90/10-70/30, a glass transition temperature of 80-95 deg. and a haze of an oriented part of 30% or less. The haze of a sheetlike material having a thickness of 0.3mm when such a mixture of polyester and polycarbonate is mixed in a melted state at a temperature range of 280-320 deg.C for 1-3min, and then injection molded to be elongated to an area magnification of 12.5 times is 30% or less. Such a hollow molded form has heat resistance of 85 deg.C and excellent transparency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hollow molded polyester product, and more particularly to a hollow molded product having excellent transparency and heat resistance.

[0002]

2. Description of the Related Art Polyester, especially polyethylene terephthalate, is widely used for fibers, films, industrial resins, bottles, cups, trays, etc. because of its excellent mechanical and chemical properties. Of these, hollow molded articles such as bottles show a marked increase in consumption. However,
Polyethylene terephthalate has a glass transition temperature of 70 ° C.
Since it is in the vicinity, it is difficult to apply it to applications such as sterilizing the contents at high temperature.

In order to solve this problem, a method of heat setting in a mold after stretching and blowing (for example, Japanese Patent Laid-Open No. Sho 6)
3-185620, JP-A-63-280615, etc.) and a method of melt blending an aromatic polyester (for example, JP-A-50-96652 and JP-A-57-1).
No. 60, etc.), and a method of forming a multi-layer bottle in which heat-resistant resins such as aromatic polyester and polycarbonate are laminated (for example, JP-A-55-154234 and JP-A-59-204).
No. 552, JP-A-62-208924, etc.) and a method of copolymerizing a rigid monomer (for example, JP-A No. 2-9).
7518, JP-A-2-97521, etc.) have been proposed.

However, the method (1) has a problem of mold fouling due to exudation of oligomers in polyester,
The method (3) has a problem that uneven thickness of the hollow molded body is likely to occur. It has been pointed out that it is difficult to control the conditions at the time of co-injection by the other method, and in the further method, since a new compound is introduced from the polymer stage, the production of the polymer is difficult and expensive. There is a problem.

[0005]

DISCLOSURE OF THE INVENTION The present inventors have paid attention to the high glass transition point of polycarbonate and studied blending with it. However, although the heat resistance of the molded product is improved, there is a problem that the transparency is impaired.

Therefore, the inventors arrived at the present invention as a result of extensive studies to solve this problem.

[0007]

According to the present invention, the ratio of ethylene terephthalate units to carbonate units is 90/1.
0-70 / 30 and glass transition temperature 80-95
C. and a haze in the stretched portion of 30% or less, which is a hollow polyester body, wherein a mixture of polyester and polycarbonate in a molten state is used.
After mixing for 1 to 3 minutes in the temperature range of 0 to 320 ° C., the thickness when the mixture is injection molded and stretched to have an area ratio of 12.5 is 0.
The haze of a 3 mm sheet is 30% or less.

The present invention will be described.

In the present invention, the hollow molded article means a tobolt, a cup,
A tray, etc. Further, in the present invention, the polyester is a polyester whose main acid component is terephthalic acid and whose main glycol component is ethylene glycol. Here, "mainly" means an amount exceeding 85 mol%. Therefore, in the range of less than 15 mol%, ester units other than terephthalic acid and ethylene glycol can be contained, and such copolymerization components include terephthalic acid, dicarboxylic acids other than ethylene glycol, and diols or oxyacids. Specifically, aromatic dicarboxylic acids such as isophthalic acid, naphthalenedicarboxylic acid,
Diphenyl dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenyl sulfone dicarboxylic acid, diphenyl ketone dicarboxylic acid, sodium-sulfoisophthalic acid,
Dibromoterephthalic acid and the like; aliphatic dicarboxylic acids such as decalin dicarboxylic acid, hexahydroterephthalic acid and the like; aliphatic dicarboxylic acids such as malonic acid, succinic acid, adipic acid and the like. As the glycol component, aliphatic diols such as diethylene glycol, trimethylene glycol, tetramethylene glycol, hexamethylene glycol and the like; aromatic diols,
For example, hydroquinone, catechol, naphthalene diol, resorcin, 4,4'-dihydroxy-diphenyl-sulfone, bisphenol A [2,2'-bis (4-
Hydroxyphenyl) propane], tetrabromobisphenol A, bishydroxyethoxy bisphenol A
Alicyclic diols, such as cyclohexanediol, etc .; aliphatic oxycarboxylic acids, such as glycolic acid,
Hydroacrylic acid, 3-oxypropionic acid, etc .; Alicyclic oxycarboxylic acid, such as asiatic acid, quinobaic acid, etc .; Aromatic oxycarboxylic acid, such as salicylic acid, m-
Examples thereof include oxybenzoic acid, p-oxybenzoic acid, mandelic acid and atrolactic acid. Furthermore, within the range where the polyester is substantially linear, trifunctional or higher polyfunctional compounds such as glycerin, trimethylolpropane, pentaerythritol, trimellitic acid, trimesic acid, pyromellitic acid, tricarballylic acid, and gallic acid are used. It may be copolymerized, and if necessary, a monofunctional compound such as o-benzoylbenzoic acid or naphthoic acid may be added.

The polycarbonate used in the present invention is
4,4-dioxydiallyl alkane-based polycarbonate, for example, bis (4-hydroxyphenyl) methane, bis (4-hydroxyphenyl) ethane, 2,2-
(4-hydroxyphenyl) propane, bis (4-hydroxy-3,5-dichlorophenyl) methane, 2,2-
It is a polycarbonate obtained from (4-hydroxy-3,5-dimethylphenyl) propane, bis (4-hydroxydiphenylalkane) and phosgene or diphenylcarbonate.

The composition used in the present invention has a mixing ratio of polyester and polycarbonate of 90/10 to 70/3.
It is 0. When the content of polycarbonate is less than 10%, the degree of improvement in heat resistance of the molded product is small, and when it exceeds 30%, it is difficult to obtain a stable molded product. Therefore, the preferred mixing ratio is 1
2 to 25%.

The glass transition temperature of the hollow molded article of the present invention is 8
It is necessary to be 0 ° C or higher. If it is lower than 80 ° C, desired heat resistance cannot be obtained. The glass transition temperature is preferably 85 ° C or higher.

The haze in the stretched portion of the hollow molded article of the present invention must be 30% or less. When it exceeds 30%, the transparency which is a feature of the present invention is impaired. The haze is preferably 20% or less. In order to obtain the highly heat resistant and highly transparent molded product of the present invention, it is necessary to appropriately select the melt mixing conditions of polyester and polycarbonate. Depending on the pressure applied during mixing and the shearing action, 1-3 at 280-320 ° C
Mix in the molten state for a minute. When the melting temperature exceeds 320 ° C, foaming and discoloration due to thermal decomposition of polyester and polycarbonate are remarkable, and when the melting temperature is less than 280 ° C, transesterification reaction does not proceed and compatibility is insufficient and a transparent bottle cannot be formed. When the mixing time is less than 1 minute, a transparent bottle cannot be obtained due to insufficient compatibility, but when the mixing time exceeds 3 minutes, foaming, discoloration, etc. due to thermal decomposition are promoted and the effect of improving compatibility is small.

The specific blending method is, for example, in the case of the injection blow method, when the preform is molded, until just before the resin flows into the injection mold, or in the case of the extrusion blow method, the resin is dies. It suffices that the polyester and the polycarbonate are blended by just before being further extruded.
Therefore, polyester and polycarbonate may be supplied to an injection molding machine or an extrusion molding machine in the form of pellets or the like for kneading, or may be melt kneaded in advance and the mixture may be pelletized.

[0015]

EXAMPLES The present invention will be specifically described below with reference to examples.

The mixing ratios in the examples are parts by weight, and the characteristic values are determined by the following methods. (A) Heat resistance: A 1000 cm ³ bottle was molded and the appearance change after filling with hot water at 85 ° C. was observed. (B) Glass transition temperature (Tg): A sample melted at 290 ° C. and then rapidly cooled to 0 ° C. was measured with a differential calorimeter (using DSC-20 type manufactured by Seiko Denshi Kogyo) at a temperature rising rate of 20 ° C./min. (C) Haze: injection molding machine M manufactured by Meiki Seisakusho
-100 ° C in -100DM at 315 ° C with a basis weight of 50 g and a wall thickness of 3.7 m
m preform, blow stretched to an area ratio of 12.5 times, body thickness 0.3 mm, internal volume 1000 c
a hollow molded body m ^3. The straight body part of this molded body was cut out and measured with Nippon Denshoku Industries Co., Ltd. 1001DP type integrating sphere type light transmittance meter.

[0017]

Examples 1 to 6 Teijin Polyester Resin TR-8550
Table 1 for T and Teijin Chemicals Polycarbonate L-1225L
After chip blending at the ratio shown in, a preform of 50 g was molded at 315 ° C. by an injection molding machine M-100DM manufactured by Meiki Seisakusho.

This was blow-molded by a blow molding machine RHB-L manufactured by Cincinnati Miracron Co., Ltd.
A hollow molded body having a size of 3 mm and an internal volume of 1000 cc was obtained. The characteristics of this molded product are shown in the right column of Table 1.

[0019]

[Table 1]

[0020]

[Comparative Examples 1 to 7] When PC is less than 10%, a transparent bottle can be obtained if melt blending conditions are appropriate, but heat resistance is poor (Comparative Example 4). Even if PC is in the range of 10 to 30%, if the melt blending temperature is low, the compatibility becomes insufficient and a transparent bottle cannot be obtained (Comparative Example 5). If the melt-blending time exceeds 3 minutes, foaming due to decomposition of PC or PET results in defective molding (Comparative Example 6). If the PC content exceeds 30%, the blow moldability will deteriorate even if the melt blending conditions are appropriate,
A normal bottle cannot be obtained (Comparative Example 7).

[0021]

The hollow molded article according to the present invention has a heat resistance of 85 ° C. and is excellent in transparency.

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Claims (1)

[Claims] 1. A polymer mixture in which the ratio of ethylene terephthalate units to carbonate units is 90/10 to 70/30 is mixed in the molten state in the temperature range of 280 to 320 ° C. for 1 to 3 minutes and then injected. Molded, area magnification 1
Haze of 0.30mm thickness when stretched 2.5 times is 3
A polyester hollow molded article characterized by being 0% or less.