JPS61142140A - Can - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

TECHNICAL FIELD The present invention relates to a can filled with food, etc., which has lids fixed to openings at both ends of a biaxially stretched synthetic resin pipe of a predetermined length containing metal powder.

BACKGROUND ART In order to fill and enclose contents in a synthetic resin container, a lid is usually attached to the opening after filling the container with the contents open at one end.

In this case, the container with one end open is manufactured by blow molding or cold or hot working.

As a blow molding method, a blow molding method that involves a stretching process (hereinafter referred to as the hollow stretching method) is common, and it is used to make PET bottles, etc.
It is widely used in the production of various types of ash, and also cold and hot.
As hot processing methods, cold processing methods such as meta/ping process and hot processing methods such as vacuum pressure forming are known.

Problems with the conventional technology However, with the hollow stretching method, there is a limit to balancing the stretching ratio in the longitudinal and lateral directions, so the strength cannot be increased, and vertical cracks may occur during seaming, and the parting line may not be visible in terms of appearance. There is a drawback that (mold seams) remain.

Further, stamping and vacuum-pressure forming methods have the disadvantage that orientation is insufficient due to the nature of the forming method, resulting in insufficient strength and furthermore, there is a limit to deep drawing.

Therefore, the can with a lid attached to the open end of the container with one end open can be sealed only once, but
Either it was not possible to form a container with the desired depth for the diameter, or even if it could be formed, the inherent drawbacks of containers with one end open, such as insufficient strength, were still connected to the can. Ta.

Furthermore, due to the inherently low thermal conductivity of synthetic resins, when the contents are cooled before being eaten, such as in soft drinks and frozen desserts,
There was a problem in that it took a long time to cool down.

OBJECTS OF THE INVENTION In view of the above-mentioned circumstances, an object of the present invention is to provide a can with high strength and thermal conductivity, the main component of which is a synthetic resin gib having a desired diameter and height.

Structure of the Invention The present invention has been made to achieve the above object.
The gist of the can is that the main body is a synthetic resin pipe that is biaxially stretched and contains metal powder, has a constriction and an expanded portion at both ends of the main body, and has a lid fixed to the expanded portion.

Figures 1 to 9 show an example of the method for manufacturing cans according to the present invention, and the synthetic resins used are polyethylene, isotactic polypropylene, polyethylene terephthalate, nylon, polyhinyl chloride, polyacrylic acid ester, etc. It is a plastic resin.

The metal powder to be included in the synthetic resin has a higher thermal conductivity than the synthetic resin, such as aluminum powder and iron powder, and the content is preferably 3 to 30% by weight, and if it is less than 3% by weight, the improvement efficiency will be reduced. If it is insufficient and exceeds 30% by weight, molding problems such as uneven thickness and insufficient orientation are likely to occur.

In order to impregnate the metal powder, it is preferable to knead it in a mixer, pass through rolls, make it into pellets, and then apply it to a molding machine.If the mixture is triblended and then applied to a molding machine, there is a risk of uneven extrusion and poor dispersion. The particle size of the metal powder is preferably fine to some extent from the viewpoint of dispersion and stretchability, and may be several hundred microns.

The thermal conductivity (ASTM C177) is, for example, 0.3 Wm-' for isotactic polypropylene.
, aluminum powder 3A0X10-3Wm"k", and iron 83.5X10-3Wm-'k".

Fig. 1 is a diagram of a biaxially stretched synthetic resin pipe manufacturing apparatus, and the reference numeral 11 in the figure is an extrusion device in which molten resin containing metal powder is extruded into a cylindrical shape at a predetermined speed -l through a die lla at the tip. It is a machine. The extruded resin 12a passes through a calibration die 13 to form a cylindrical resin 12b having a predetermined diameter, and is led to a vacuum chamber 14. At this time, the temperature at the center of the thickness of the resin 12b is, for example, 90 to 11 if it is high-density polyethylene.
0C, 1oo for isotactic polypropylene
The temperature is maintained at a temperature suitable for stretching depending on the type of resin, such as 130°C.

In the vacuum chamber 14, the diameter of the resin 12b is expanded,
The outer diameter is D20 synthetic resin and 12c, but this E
Since the eve 12c is taken up by the caterpillar set TIFJ 15 at a speed v2 faster than v1, the resin 12b is also stretched in the length direction.
It becomes Iso 12c. Therefore, by appropriately selecting the outer diameter dimension DllD2 and the speeds vl and v2, Guia' 12c can be stretched to desired stretching ratios in both the vertical and horizontal directions, resulting in a biaxially stretched pipe that is relatively thin but has high strength. Become.

Next, the sleeve 12c is subjected to a heat treatment (not shown) to remove distortion, and then cut to a predetermined length by a forceps 16.

In this case, the cutter 16 is configured to move parallel to the mother groove 12c at a speed v2 until the cutting is completed, so that the biaxially stretched pipe 12 of the predetermined length shown in FIG. 2 can be continuously obtained.

This biaxially stretched tube 12 of a predetermined length is heat-treated and undergoes a change over time. Eve's entire distortion is removed.

Next, the strain-removed pipe 12 of a predetermined length is moved back at one end as shown in FIG. -17, and insert the other end into the mold 18 to narrow the opening. In this case, the mold 18 is provided with an inner mold 18a that is movable up and down to level the inner surface of the drawing area, but if the drawing is too much, the inner mold 18a
This is undesirable as it creates wrinkles that cannot be smoothed out. Similarly, the one end side is also constricted to form a cylinder 19 having apertures at both end openings as shown in FIG.

As shown in FIG. 5, this cylindrical body 19 is held at one end by a retracting stopper 17, the upper edge of the aperture is opened by a male die 20, and the same operation is performed at the other end. By this operation, a synthetic resin gib (hereinafter referred to as pipe) 23 having constrictions 21 and widened portions 22 at both ends as shown in FIG. 6 is formed.

There is no particular restriction on the height Ll of the expanded portion 22, but it is preferably about 1/20 of the height L2 of the opening from the overall shape, and the maximum diameter D3 of the end of the expanded portion 22 is: In order to prevent it from protruding beyond the outer periphery of each can, it is preferably equal to or slightly smaller than the outer diameter of the rib 23 (the outer diameter of the biaxially stretched mother rib 12a) D2.

Depending on the type of synthetic resin and the type and content of metal powder, the main body can be seen through, and can be made thinner and lighter by biaxial stretching, and can be squeezed or incinerated after use.

In addition, as shown in FIG. 7(a) and (b), the lid to be attached to the lid 24 has an outer tip 24a that is connected to the expanded portion 24.
A shallow dish-shaped thing made of synthetic resin that comes into contact with the inner surface 22a of the is used. There are no particular restrictions on the molding method, such as injection molding or vacuum-pressure forming, but vacuum-pressure forming is inexpensive and economical because the drawing margins are shallow.

There are various ways to attach the lid, for example:
The well-known ultrasonic welding is efficient. Ultrasonic welding is the 8th
As shown in the figure, the lid 24 is placed on the expanded portion 22 and pressed by the ultrasonic horn 25. In this case, it is necessary to provide a support (not shown) on the outside of the expanded portion 22 to support the pressing force of the horn 25. In this way, horn 2
Ultrasonic waves are emitted from the 5th direction, and the 9th surface 24a of the lid 24 is welded to the inner surface 22a of the expanded portion. After one lid is bathed, the contents are filled and the other lid is attached to form the can 26 shown in FIG. In this case, a pull top (open-hole gripping piece) 27 may be provided on the other lid.

In the above description, the lid 24 is made of synthetic resin, but the lid 24 is not limited to this.As shown in FIG. A metal lid 28 or the like may also be used.

Effects of the Invention As described above, the can according to the present invention is made of synthetic resin or ino containing biaxially stretched metal powder, so it can be made thinner in terms of strength and lighter in weight than conventional cans. They are cheaper than steel and aluminum cans, are available in a variety of resin materials, and can even be made to see through the contents. In addition, since the expansion part is provided following the constriction, it does not protrude beyond the outer periphery of the can body, allowing stable packaging without wasting space. Therefore, it can completely eliminate the pollution caused by conventional cans, and has many advantages such as improved thermal conductivity and shortened cooling time due to the presence of metal powder.

[Brief explanation of the drawing]

Figures 1 to 9 show an example of the method for manufacturing cans according to the present invention. Fig. 2 is a perspective view of a biaxially stretched synthetic resin pipe containing a predetermined length of metal powder, Fig. 3 is a longitudinal cross-sectional view of a device with apertures provided at both ends, and Fig. 4 is a perspective view of a biaxially stretched synthetic resin pipe containing a predetermined length of metal powder. 5 is a vertical sectional view of a device for providing an expanded portion, FIG. 6 is a perspective view of a tube with constrictions and expanded portions at both ends, and FIG. Figure 7(a) is a perspective view of the synthetic resin lid, and Figure 7(b) is
FIG. 7(a) is a cross-sectional view taken along the arrow ■-■, FIG. 8 is a longitudinal cross-sectional view showing a state in which the lid is welded to the expanded portion by ultrasonic waves, and FIG. 9 is a cross-sectional view of the can according to the present invention. FIG. 10 is a perspective view showing the embodiment, and FIG. 10 is a longitudinal sectional view showing another embodiment of the can. DESCRIPTION OF SYMBOLS 21... Constriction, 22... Expanding part, 22a... Inner surface, 23... Synthetic resin pipe having constriction expanding part, 24... Lid, 26... Can, 28...・Metal lid.

Claims (1)

[Claims] A can whose main body is a synthetic resin pipe that is biaxially stretched and contains metal powder, has a constriction and an expanded part at both ends of the main body, and has a lid fixed to the expanded part.