JPH06219436A - Heat-resistant container and its preformed body - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a biaxially stretch blow-molded container having a small thickness and excellent heat resistance, and a preform for manufacturing such a container. [Structure] A preform 1 for a heat-resistant container in which a mouth portion 2 is made of a single layer of heat-resistant resin or polyester resin, and a shoulder portion 3, a body portion 4 and a bottom portion 5 are made of a heat-resistant resin layer 9 and a polyester resin layer 8, and It is a heat-resistant container obtained by biaxially stretch blow molding the preform 1 and then cutting the mouth 2.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a heat-resistant container comprising a heat-resistant resin layer and a polyester resin layer, and a method for producing the same.

[0002]

When sterilizing the medium of various fungi and microorganisms, steam catamars such as Koch bactericidal catamanas are usually used. When Koch sterilization cattail is used, it is sterilized by a sterilization method called an intermittent sterilization method. However, in the intermittent sterilization method, since it is necessary to heat the culture medium several times, the substance in the culture medium may be changed. In addition, since heat-resistant spores may be mixed in, it may not be possible to sterilize by the intermittent sterilization method.

Therefore, pressure sterilization using a pressure sterilizer called an autoclave has come to be carried out. Since an autoclave container is handled under high temperature and high pressure, a container made of polycarbonate having excellent heat resistance and pressure resistance has been used as an autoclave container.

Autoclave containers made of polycarbonate are manufactured by so-called direct blow molding because biaxial stretch blow molding is difficult. A container formed by direct blow molding has a non-uniform wall thickness and is likely to be optically distorted in some cases. Therefore, there is a problem that the container is not necessarily suitable as an autoclave container requiring internal observation. Moreover, since it is thick, there is a problem that the amount of resin used is large and the product cost is high.

Therefore, it is an object of the present invention to provide a biaxially stretch blow-molded container having a small wall thickness and excellent heat resistance, and a preform for manufacturing such a container.

[0006]

As a result of earnest research in view of the above object, the present inventors have found that the mouth portion is formed of a single layer of a heat-resistant resin such as polycarbonate or a polyester resin having excellent stretchability such as polyethylene terephthalate. The shoulder, body and bottom are made of a heat-resistant resin layer and a polyester resin layer to form a preform, and the preform is biaxially stretch blow molded, and then the mouth is cut to obtain a thin wall. Then, they have found that a biaxially stretched blow molded container having excellent heat resistance can be obtained, and have conceived the present invention.

That is, in the preform for heat-resistant containers of the present invention, the mouth is made of a single layer of heat-resistant resin or polyester resin, and the shoulder, body and bottom are made of heat-resistant resin layer and polyester resin layer. Is characterized by.

The heat-resistant container of the present invention comprises a preformed body having a mouth made of a single layer of a heat-resistant resin or a polyester resin, and a shoulder, a body and a bottom made of a heat-resistant resin layer and a polyester resin layer. After the axial stretch blow molding, the mouth is cut.

[0009]

The present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a flowchart showing the manufacturing process of the heat resistant container of the present invention. Hereinafter, the method for producing the heat-resistant container of the present invention will be described with reference to the flow chart.

(1) Preparation of Preform To manufacture the heat resistant container of the present invention, first, a preform is prepared. FIG. 2 is a schematic sectional view showing an example of a preformed body of the heat-resistant container of the present invention. The preform 1 comprises a mouth part 2 having a support ring 6, a shoulder part 3, a body part 4 and a bottom part 5.

The shoulder portion 3, the body portion 4 and the bottom portion 5 of the preform 1 have a multilayer structure in which a polyester layer 8 and a heat resistant resin layer 9 are laminated. The layer structure shown in FIG. 2 is a polyester layer / heat resistant resin layer / polyester layer, but there is no particular limitation as long as it is composed of a polyester layer and a heat resistant resin layer. Heat-resistant resin layer / polyester layer / with changed positions /
The heat-resistant resin layer may be used, or a five-layer structure of polyester layer / heat-resistant resin layer / polyester layer / heat-resistant resin layer / polyester layer may be used, and various layer configurations are possible. With such a multilayer structure, the heat resistance of the heat resistant resin layer 9 and the stretchability of the polyester resin layer 8 can be imparted to the finally obtained container.

Since the bottom portion 5 is less stretchable than the shoulder portion 3 and the body portion 4 and is somewhat inferior in heat resistance, the ratio of the heat-resistant resin layer to the polyester resin layer increases as it approaches the bottom portion 5. Is preferred.

On the other hand, the mouth 2 of the preform 1 has a single layer structure. Although the single layer structure composed of the polyester resin layer 8 is shown in FIG. 2, it may be a single layer structure composed of the heat resistant resin layer. In the present invention, this mouth portion 2 is cut, as will be described later. However, if the part to be cut has a multi-layered structure, cracks may form from the joints of the layers on the cut surface,
The problem of cracking occurs. Therefore, since the portion having the single-layer structure is cut, the opening 2 of the preform 1 is cut.
The purpose is to use a single-layer structure. In the present specification, the term “portion” means the mouth portion that is not stretched during biaxial stretch blow molding and its peripheral portion, and includes the lower portion of the support ring 6.

As the polyester resin forming the polyester resin layer of the preform 1, a thermoplastic resin composed of saturated dicarboxylic acid and saturated dihydric alcohol can be used. As the saturated dicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, naphthalene-1,4- or 2,6-dicarboxylic acid, diphenyl ether-4,4'-dicarboxylic acid,
Aromatic dicarboxylic acids such as diphenyldicarboxylic acids and diphenoxyethanediethanedicarboxylic acids, aliphatic dicarboxylic acids such as adipic acid, sebacic acid, azelaic acid, decane-1,10-dicarboxylic acid, and alicyclic compounds such as cyclohexanedicarboxylic acid A dicarboxylic acid or the like can be used. As the saturated dihydric alcohol, aliphatic glycols 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 are used. Glycols, alicyclic glycols such as cyclohexanedimethanol, 2,2-bis (4'-β-hydroxyethoxyphenyl) propane, and other aromatic diols can be used. As the polyester resin composed of such a saturated dicarboxylic acid and a saturated dihydric alcohol, it is preferable to use polyethylene terephthalate composed of terephthalic acid and ethylene glycol.

The above polyester resin has an intrinsic viscosity of 0.5.
It has a value in the range from .about.1.5, preferably 0.55 to 0.8. Also, such polyesters are produced by melt polymerization, 1
Those that have been subjected to reduced pressure treatment or heat treatment in an inert gas atmosphere at a temperature of 80 to 250 ° C., or those that have reduced the content of oligomers and acetaldehyde which are low molecular weight polymers by solid-state polymerization are suitable.

As the heat-resistant resin forming the heat-resistant resin layer, polyarylate, polycarbonate, polyethylene naphthalate, polyacetal, polysulfone,
Polyether ether ketone, polyether sulfone, polyether imide, polyphenylene sulfide and blend polymers of these resins with polyethylene terephthalate, blend polymers between the above heat resistant resins, and further two or more resins of the above heat resistant resins And a polyethylene terephthalate blend polymer, U polymer (manufactured by Unitika, polyarylate / polyethylene terephthalate blend polymer) and the like can be used. Of these, polyarylate, U polymer, polycarbonate, and a blend polymer of polycarbonate and polyethylene terephthalate are particularly preferable.

In the above polyester resin and heat-resistant resin, stabilizers, pigments, antioxidants, heat deterioration inhibitors, UV deterioration inhibitors, antistatic agents, antibacterial agents, etc. are included within the range not impairing the object of the present invention. Additives and other resins can be added in appropriate amounts.

The preform 1 described above can be produced by co-injection molding a polyester resin and a heat-resistant resin by the method exemplified in JP-A 1-294025.

(2) Biaxial Stretch Blow Molding Next, biaxial stretch blow molding is performed using the obtained preform 1. The biaxial stretch blow molding may be performed by a known method. As described above, the preform 1 has the polyester resin layer 8 and the heat resistant resin layer 9. During stretch blow molding, the polyester resin layer 8 has excellent stretchability, while the heat-resistant resin layer 9 has poor stretchability. However, when the multilayer structure according to the present invention is used, heat resistance is poor. The resin layer 9 is also sufficiently stretched together with the polyester resin layer 8.

Therefore, the shoulder portion 3 and the body portion 4 of the preform 1 are sufficiently stretched by the biaxial stretch blow molding to have a thin wall thickness. In addition, the thickness is constant to some extent without any optical distortion. The mouth 2 is not stretched because it is held in the mold, and the bottom 5 has a low degree of stretching due to the nature of biaxial stretch blow molding.

(3) Heat treatment The intermediate molded body obtained by the biaxial stretch blow molding is rapidly heated by heated pressurized air, radiant heat and the like. By performing such heat treatment, the stress at the time of stretch molding can be relaxed, and crystallization under stretch orientation can be promoted. Therefore, the volume contraction rate after mold release is reduced, and whitening due to spherulites is eliminated. Also,
In the above-mentioned biaxial stretch blow molding, the intermediate molded body is molded larger than the intended final shape container, and the intermediate molded body is contracted while being heated to the crystallization temperature of the crystalline plastic or higher and lower than the melting temperature. Alternatively, the biaxially stretch blow molding may be performed again to obtain a container having a desired shape. In this case, the whitening phenomenon can be eliminated, and formation of unnecessary concave portions on the surface and occurrence of irregular distortion can be prevented.

(4) FIG. 3 shows the mouth of the intermediate compact after the heat treatment for cutting the mouth. Mouth 2
It is composed of either a polyester resin layer or a heat resistant resin layer. Heat resistance is imparted by stretching these thermoplastic resins, but the mouth portion 2 is inferior in heat resistance because it is not stretched as described above. In the present invention, by cutting the mouth portion 2, the obtained container is formed only from the stretched portion, and has excellent heat resistance.

The mouth 2 is cut slightly above the dotted line A from the end of the monolayer. The cutting position is a single-layer portion. If the cutting position has a multi-layer structure, the joint portion between the polyester resin layer 8 and the heat-resistant resin layer 9 on the cut surface is cracked or cracked. This is because there is a risk.

The container obtained by the above steps is shown in FIG. The container 7 includes a mouth portion 2, a shoulder portion 3, a body portion 4 and a bottom portion 5. The mouth portion 2, the shoulder portion 3 and the body portion 4 are excellent in stretchability and have a heat resistant resin layer, and the bottom portion 5 is slightly inferior in stretchability, but the ratio of the heat resistant resin layer is large. in this way,
Each part of the container of the present invention has excellent heat resistance and can withstand high temperature sterilization at 120 to 130 ° C.

The present invention has been described above with reference to the accompanying drawings. However, the present invention is not limited to this, and various modifications can be made without departing from the idea of the present invention. For example, the size and shape of the container can be variously changed according to the purpose of use,
The cutting position of the mouth may be slightly changed depending on the position of the multilayer structure.

[0026]

As described in detail above, in the heat-resistant container of the present invention, the mouth portion is composed of either a single layer of the heat-resistant resin layer or the polyester resin layer, and the portion other than the mouth portion is the heat-resistant resin layer. It is formed by biaxially stretch-blow-molding a preform composed of and a polyester resin layer, and then cutting the mouth part made of a single layer.

The heat-resistant container of the present invention as described above has the following advantages. 1) It has excellent heat resistance and can be sterilized at high temperature. 2) Since it can be molded into a thin wall, it can be manufactured with a small amount of raw material resin. 3) Because it has a certain amount of uniform thickness and is highly transparent,
The internal observation can be performed well. 4) Lightweight, so work and transportation is easy.

The heat-resistant container of the present invention is suitable for an autoclave container, a container for culturing various tissues or cloned plants, a container for merigulin cultivation, and the like.

[Brief description of drawings]

FIG. 1 is a flowchart showing steps for producing a heat-resistant container according to the present invention.

FIG. 2 is a schematic cross-sectional view showing an example of a preform of the present invention.

FIG. 3 is a schematic cross-sectional view showing a mouth portion of an intermediate molded body of the heat resistant container of the present invention.

FIG. 4 is a schematic sectional view showing an example of a heat-resistant container of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Preformed body 2 ... Mouth part 3 ... Shoulder part 4 ... Body part 5 ... Bottom part 6 ... Support ring 7 ... Heat-resistant container 8 ... Polyester resin layer 9 ... Heat-resistant resin layer

Claims (2)

[Claims] 1. A preform for a heat-resistant container, the mouth of which is made of a single layer of heat-resistant resin or polyester resin, and the shoulder, body and bottom of which are made of a heat-resistant resin layer and a polyester resin layer. 2. A biaxially stretch-blow-molded preform having a mouth made of a single layer of a heat-resistant resin or a polyester resin, and a shoulder, a body and a bottom made of a heat-resistant resin layer and a polyester resin layer, A heat resistant container, characterized in that the mouth is cut.