JP3075431B2 - Preform warmer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, a preform heat insulating apparatus provided during a process of manufacturing an acrylonitrile resin container.

[0002]

2. Description of the Related Art An acrylonitrile-based resin container produced by biaxially stretch-blow-molding an acrylonitrile-based resin bottomed tubular body (hereinafter referred to as a preform) has excellent properties in gas barrier properties and transparency. And
Moreover, since it is lightweight and has excellent stability against many solvents, it is widely used as various containers, for example, containers for filling foods, medicines, cosmetics, and beverages containing carbon dioxide gas. .

[0003] However, in the case of the container obtained by the biaxial stretching blow molding method of the acrylonitrile-based resin, the raw material acrylonitrile-based resin itself contains a trace amount of an unpolymerized acrylonitrile monomer. Traces of unpolymerized acrylonitrile monomer are produced, which inevitably are contained in the container by the biaxial stretch blow molding method and have the potential to migrate into the contents of the container.

[0004] For this reason, for example, Japanese Patent Publication No. 56-54321
As described in JP-A-54-148059 or JP-A-54-148059, by irradiating an electron beam to a preform of a thermoplastic resin containing an acrylonitrile-based resin as a main component, unpolymerized preform in the preform is irradiated. Methods for reducing the content of acrylonitrile monomer have been proposed.

However, the method of irradiating the acrylonitrile-based resin preform with an electron beam to reduce the content of unpolymerized acrylonitrile monomer in the preform is based on a method in which HCN is produced by irradiation of the electron beam. Another problem is that it is difficult to obtain an acrylonitrile-based resin container having excellent hygiene properties by a stretch blow molding method.

[0006] Accordingly, the applicant of the present invention has previously described the content of the unpolymerized acrylonitrile monomer in the preform and the amount of by-produced HCN in the production of the acrylonitrile-based resin container by the biaxial stretch blow molding method. Have been proposed to produce an acrylonitrile-based resin container by a biaxial stretch blow molding method which is excellent in hygiene properties (JP-A-1-234225).

In the method, an electron beam or a gamma ray is irradiated to a preform formed of a bottomed tubular body of a thermoplastic resin containing an acrylonitrile-based resin as a main component, and immediately heated at a temperature of 40 ° C. or more. By performing the treatment, the unpolymerized acrylonitrile-based monomer in the preform is reduced to 0.1 ppm or less, and then the preform is subjected to biaxial stretch blow molding. This is a method for forming an axial stretch blow molded article.

[0008]

However, in the above-mentioned molding method, the heat-treated preform is exposed to the atmosphere while being sent to the blow molding machine in the next step, so that the temperature of the preform falls or the temperature varies. As a result, there is a problem that the molding efficiency is poor because the molding is not stable, and the quality of the molded product is not stable.

Therefore, the preform warming apparatus of the present invention
An object of the present invention is to improve the molding efficiency and the quality of a molded product by making the temperature of a preform supplied to a blow molding machine uniform to a predetermined temperature.

[0010]

According to a first aspect of the present invention, there is provided a star wheel which rotates by holding a preform at a predetermined interval on an outer periphery thereof in a heat insulating furnace in which hot air circulates. And a preform conveying means comprising:

According to a second aspect of the present invention, a pair of endless chains circulating in the longitudinal direction of the insulated furnace are opposed to each other in an insulated furnace in which hot air is circulated, and a plurality of endless chains are provided outside the endless chains at regular intervals. And a preform conveying means provided with the elastic body.

[0012]

In the first aspect of the present invention, the preform is held and held in a rotating star wheel in a heat-retaining furnace and moves slowly, so that the preform is heated and maintained for a sufficient time, thereby making the temperature of the preform uniform. Achieved.

In the second aspect of the present invention, the preform moves slowly while being sandwiched by the elastic members attached to a pair of endless chains orbiting the insulated furnace, so that the temperature can be made uniform.

[0014]

1 to 4 show an embodiment of the first invention. In the drawing, reference numeral 1 denotes a flat circular insulated furnace, 2 denotes a preserving furnace for supplying the preform 4, 3 denotes a preserving furnace for discharging the preform 4, and each of the preheating furnaces 1, 2 and 3 is ducking with a heat insulating material. And are in communication with each other. The supply-side and discharge-side insulated furnaces 2 and 3 are respectively installed so as to be inclined downward in the traveling direction of the preform 4, and inclined chutes 5 and 6 are respectively penetrated therein. And
The neck ring 7 of the preform 4 is hooked on the upper end surface of each of the inclined chutes 5, 6, and the preform 4 slides in each of the inclined chutes 5, 6 by its own weight.

In the heat-retaining furnace 1, a disk-shaped star wheel 8 having a large number of recesses 9 provided at regular intervals on the outer periphery is rotatably installed. The concave portion 9 is cut out to a size for accommodating the preform, and the neck ring 7 of the preform 4 is hooked, whereby the preform 4 is cut.
Is held in the recess 9. A guide 10 having a substantially semicircular shape is provided outside the outer peripheral portion on one side of the star wheel 8 in order to prevent the preform 4 from dropping.

Reference numeral 16 denotes a motor which is a rotation drive source of the star wheel 8. Further, a hot air device 11 is installed at a lower portion in the heat insulating furnace 1. A hot air outlet 12 is provided on the upper surface of the hot air device 11, and a hot air supply duct 13 is provided between a side portion of the outlet 12 and a lower portion of each of the heat retaining furnaces 2 and 3. Hot air recovery ducts 14 are provided between the upper portions of the heat retaining furnaces 1, 2, 3 and the side portions of the hot air device 11, respectively.

Therefore, the hot air generated by the hot air device 11 is
A part of the air exits from the outlet 12 and rises in the insulated furnace 1, and then is collected from the collection duct 14.
After being supplied into the insulated furnaces 2 and 3 through the recovery duct 1
Collected from 4.

The preform 4 sent from a previous step such as a heat treatment step sequentially moves in the insulated furnace 2 through the inclined chute 5 on the supply side, where a certain degree of heat insulation effect is achieved by hot air. You.

The preform 4 having passed through the heat insulating furnace 2
Is pushed by the succeeding preform 4 at the tip of the inclined chute 5 as shown in FIG. 3, and is sequentially accommodated in the concave portion 9 of the preform 8 rotating at a predetermined speed.
Make a half circle inside. The star wheel 8 is preferably rotated relatively slowly, so that the preform 4
Since the preform 4 is heated and maintained by the hot air for a sufficient time, the preform 4 is made uniform at a predetermined temperature, and the preservation effect is sufficiently achieved.

The preform 4, which is held by the star wheel 8 and makes a half turn in the heat retaining furnace 1, moves to the inclined chute 6 on the discharge side. That is, as shown in FIG. 4, the guide portion 15 which is smoothly curved in the direction opposite to the rotation direction of the star wheel 8 is formed at the start end of the inclined chute 6, and has moved together with the star wheel 8. Preform 4
The guide 15 smoothly moves to the inclined chute 6. Next, the preform 4 is sent to the blow molding step by sequentially sliding the inclined chute 6 in the heat insulating furnace 3 by its own weight.

Next, an embodiment of the second invention will be described with reference to FIGS. In the figure, reference numeral 20 denotes an insulated furnace installed in a downwardly inclined shape in the traveling direction of the preform 4, in which hot air generated by a hot air device 21 circulates through a hot air supply duct 22 and a hot air recovery duct 23. I have.

Reference numeral 24 denotes a pair of endless chains which are installed so as to face each other so as to penetrate the insulated furnace 20, and respectively circulate along the longitudinal direction of the furnace 20. A large number of elastic members 2 made of rubber or the like are provided outside each endless chain 24 as shown in FIGS.
The preform 4 is conveyed in the furnace 20 by holding the preform 4 from both sides by these elastic bodies 25. 26 is an inclined chute on the preform supply side, and 27 is an inclined chute on the discharge side.

The preform 4 sent from the previous step through the inclined chute 26 is sequentially sandwiched from both sides by the elastic bodies 25 attached to the pair of orbiting endless chains 24 so as to be held in the heat insulating furnace 20. After moving through the inside, it moves to the inclined chute 27 on the discharge side and is sent to the blow molding step. It is desirable that the endless chain 24 also circulates relatively slowly, so that the preform 4 is heated and kept warm for a sufficient time, so that the preform 4 is made uniform at a predetermined temperature and the heat keeping effect is sufficiently achieved.

[0024]

According to the present invention, the preform is heated and maintained for a sufficient time before the molding step, so that the temperature can be made uniform to a predetermined temperature, whereby the molding is stabilized and the molding is performed. Efficiency is improved, and the quality of molded products is also stably improved.

[Brief description of the drawings]

FIG. 1 is a plan view showing an embodiment of the first invention.

FIG. 2 is a front view of the same.

FIG. 3 is an enlarged plan view of a portion A in FIG. 1;

FIG. 4 is an enlarged plan view of a portion B in FIG. 1;

FIG. 5 is a plan view showing an embodiment of the second invention.

FIG. 6 is a front view of the same.

FIG. 7 is a sectional view taken along line CC in FIG. 6;

FIG. 8 is a plan view of a main part of FIG. 7;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1; Heat insulation furnace 4; Preform 8; Star foil 9; Concave part 11; Hot air device 20; Heat insulation furnace 21; Hot air device 24; Endless chain 25; Elastic body

────────────────────────────────────────────────── (5) References JP-A-49-36766 (JP, A) JP-A-49-5162 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B29C 49/00-49/80 B29C 35/00-35/18

Claims (2)

(57) [Claims] 1. A preform warming apparatus comprising: a preform conveying means made of a star wheel that rotates while holding and holding a preform at regular intervals on an outer peripheral portion in a warming furnace in which hot air circulates. . 2. A pair of endless chains that circulate in the longitudinal direction of the insulated furnace are installed in the insulated furnace in which hot air circulates, and a plurality of elastic bodies are attached to the outside of each of the endless chains at regular intervals. A preform warming device comprising a preform conveying means comprising: