JPH03275327A - stretch blow molded containers - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a stretch blow molded container.More specifically,
This invention relates to a stretch blow-molded container whose main resin is polyethylene terephthalate and whose bottom part has improved thermal stability.

(Prior Art) Stretch-blown bottom containers made of polyethylene terephthalate are well known.

Stretch-blown bottom shapes are made by heating and softening a bottomed cylindrical preform in a blow mold, blowing pressurized air into it, and expanding it through the opening of the preform. This method involves stretching the preform, pressing a stretching iron against the bottom of the preform, and stretching the preform in the longitudinal direction to shape the bottom. As a result, the preform is stretched in the longitudinal and circumferential directions.

When the preform is made of polyethylene terephthalate, it is crystallized by stretching, and heat resistance, rigidity, etc. are significantly improved. The resulting polyethylene terephthalate stretch-blown bottom container has excellent physical properties (lightness, transparency,
Due to its moderate rigidity, etc., it is widely used as containers for beverages including carbonated drinks, seasonings, cosmetics, liquid detergents, etc.

(Intelligence M to be Solved by the Invention) By the way, in the case of the stretch-blown bottom shape, the body of the container is mainly stretched, and the mouth and neck and the bottom are not stretched at all, or are only slightly stretched.

Some drinks are heated to 80-100℃ to maintain their hygiene.
Some products are heat sterilized and then filled into containers. However, the bottom portion was not crystallized due to unstretched or weak stretching, and was thermally deformed by heating and filling, making the container unable to stand on its own.

Some containers that can stand on their own even when subjected to thermal deformation have a bottom portion that protrudes toward the inner surface of the container via an uneven step. However, since such a container merely absorbs thermal deformation in its shape, it has not been possible to avoid the problem that the container capacity varies due to variations in thermal deformation.

An object of the present invention is to provide a stretch-blow-molded container that has improved heat resistance at the bottom and is free from thermal deformation.

(Means for Solving the Problem) In order to achieve this object, the invention of claim (1) provides a stretch blow-molded container consisting of a mouth and neck, a shoulder, a body, and a bottom, wherein the body is made of polyethylene terephthalate. Consisting of
The bottom is made of polyethylene terephthalate and has a heat distortion temperature of 100.
Provided is a stretch blow-molded container characterized by being made of a laminated structure of heat-resistant resin at temperatures above .degree. C.

Further, the invention of claim (2) provides a stretch blow-molded container that includes a mouth and neck, a shoulder, a body, and a bottom. , an oxygen barrier resin, and a heat-resistant resin having a heat distortion temperature of 100° C. or higher.

(Details of invention) The present invention will be described below with reference to the drawings.

As shown in FIG. 1A, the stretch blow-molded container according to the present invention has a mouth and neck (la), a shoulder (1b), a body (IC), and a bottom (1d).

The mouth and neck part (1a) has an opening for filling with contents, and is usually provided with a camping screw groove around the periphery. During blow molding, it is fixed by a chuck and does not expand, so it has a smaller diameter than the body (1c).

The mouth and neck part (1a) may be made of polyethylene terephthalate alone. However, since it is not stretched during blow molding, in order to improve its heat resistance, the heat distortion temperature is 1.
It is preferable to have a laminated structure of heat-resistant resin (12) with a temperature of 00°C or higher and polyethylene terephthalate (11).It is limited to those with a heat distortion temperature of 100°C or higher when the contents are heated and filled at 100°C. From what happens below,
This is to prevent thermal deformation during heating and filling.

Polyethylene terephthalate (11) and heat-resistant resin (1
2) may be laminated in any order, but in order to prevent the two from peeling off, it is desirable to have a shape in which the entire circumference of the heat-resistant resin (12) is surrounded by polyethylene terephthalate (11). It is composed of polyethylene terephthalate alone.

The shoulder (1b) is a part that connects the mouth and neck (1a) and the trunk (lc). Since it is necessary to stretch during blow molding, it is desirable that the heat resistant resin (12) not be included.

The body part (1c) serves as a storage part for the contents, and since it is stretched in the longitudinal direction and the circumferential direction during blow molding, it is desirable that the body part (1c) does not contain the heat-resistant resin (12).

Since the bottom part (1d) is not stretched at all or only slightly stretched during blow molding, a heat-resistant resin (1d) with a heat distortion temperature of 100'C or higher is used to improve heat resistance.
2) and polyethylene terephthalate (11). The reason why the heat deformation temperature is limited to 100° C. or higher is the same as in the case of the mouth and neck (Ia). The stacking order is also the same.

The container shown in FIG.
), it has a laminated structure in which oxygen barrier resin (13) is arranged on the entire surface, and the rest is the same as that in FIG. 1A.

In addition, the oxygen barrier resin (13) is a heat-resistant resin (■2
) and the oxygen barrier resin (13) may be laminated in any order.

The container shown in FIG. 1A can be manufactured by the following method.

That is, FIG. 2A shows the main parts of a multilayer injection molding apparatus for molding a preform used for manufacturing the container of FIG. 1A.

In FIG. 2A, the injection molding nozzle includes a number of coaxially combined nozzles (21) (22) (23) (24).
), a central flow path (30) is provided in the center, and a flow connected to the central flow path (30) is provided between each nozzle (21) (22) (23) (24). Road (31) (3
2) (33) are provided radially over the entire circumference. The first wave path (31) is for injecting the inner layer of polyethylene terephthalate (11), and the third flow path (33) is for injecting the outer layer of polyethylene terephthalate (11) into the -1-yabity (70). They are connected to each other upstream. Moreover, the second wave path (32) is for injecting the heat-resistant resin (12).

A rod-shaped valve (40) is slidably provided in the central flow path (30). The channels (31), (32), and (33) are opened and closed. Rod valve (4
0) is provided with an opening (41) in the direction of its solid axis, and the opening (41) reaches the side surface of the rod-shaped valve (40).

The central channel (30) is connected to the cavity (70) at its tip, and the cavity (70) is connected to the fixed mold (50).
and a movable mold (60), and has the same shape as the intended preform.

Injection molding is performed according to the time chart shown in FIG. 2B. That is, the rod-shaped valve (40) is slid backward to an appropriate position to open the third flow path (33) and connect the first flow path (31) and the opening (41) (tl). At this time, only polyethylene terephthalate (11) is injected.

This is the resin that forms the area around the opening of the container.

Next, while maintaining the connection between the first flow path (31) and the opening (41), the rod-shaped valve (40) is slid further rearward to open the second flow path (32). At this time, heat-resistant resin (12) is placed between polyethylene terephthalate (11).
) flows in, and the three layers are injected in a laminar flow state. This is the resin that constitutes the container neck (1a).

Next, the rod-shaped valve (40) is slid forward to close the second flow path (32) (t,). Only polyethylene terephthalate (11) is injected.

This is the resin that constitutes the container shoulder (1b) and body (1c).

Further slide the rod # (40) backwards to open the second stream * (32) (t4). Three layers of resin are injected. This is the resin that makes up the container bottom (1d).

Finally, close the second wave path (32), inject only polyethylene terephthalate (11) to completely cover the heat-resistant resin (12) with polyethylene terephthalate (11), and then insert the rod valve (40). Slide forward and
Close all channels (31), (32), and (33).

The molded preform is taken out by moving the movable mold (6o). The preform is as shown in FIG.

The stretch-blown bottom shape is possible by the method shown in FIG.

That is, the preform neck is sandwiched between the blow molds (81), and the preform is housed in the blow molds (81). With the preform heated and softened, the stretching rod (83) is extended to stretch the preform, and pressurized air is blown through the blow hole (84) of the blow pin (82). The preform is stretched in the longitudinal direction by a stretching rod and expanded in the circumferential direction by pressurized air.
It is pressed against a blow mold (81) to obtain a stretch blow-molded container (1).

In order to manufacture the container shown in FIG. 1B, a multilayer injection molding machine shown in FIG. 5 may be used. In Figure 5 (13
) indicates the flow path of the oxygen barrier resin, and the injection time chart is shown in FIG. The stretch blow bottom shape is the same.

In the present invention, polyarylate (wholly aromatic polyester), polycarbonate, etc. can be used as the heat-resistant resin (12). Further, as the oxygen barrier resin (13), 37°C, O% R, H.

In, 0.2X10-” cc-cml-3eC
-cml(g) or less oxygen permeability is preferred.

For example, saponified ethylene-vinyl acetate copolymer, metaxylylene group-containing polyamide, and the like. to polyamide,
Lithium chloride and copper chloride metals)
7-185349), carboxylic acid salts such as strontium carboxylate and copper carboxylate (European Publication No. 3017
When No. 19) is mixed, the oxygen barrier properties are improved.

In addition, it is desirable that the heat-resistant resin (12) in the bottom part contains 4.0 to 15% by weight of the entire container wall at that position, and the oxygen barrier resin contains 5.0% by weight or more.
In particular, the heat-resistant resin (12) is 4.0% by weight in the container shown in
It is suitable when the above conditions are included.

(Example 1) A container shown in FIG. 1A was manufactured.

Boria arylate is used as the heat-resistant resin, and Fig. 2A
A preform weighing 61 g was molded using the apparatus shown in Figure 2B according to the time chart shown in Figure 2B. The preform has a shape as shown in FIG.

The bottom shape of the stretch plow was carried out by the method shown in FIG. The capacity of the container is 1540m1, the stretching ratio is 7.8 times the area ratio,
The bottom of the container is flat and has a rounded bottom that protrudes inward.

After filling the container with hot water at 85°C and 90'C, the container was cooled to room temperature with cooling water at 20°C, and the deformation of the mouth and neck and bottom was measured. The experiments were conducted on containers in which the weight of heat-resistant resin in the mouth and neck and bottom was 0.0%, 5.7%, 8.6%, and 10.2% compared to the entire weight of the container wall at the same positions. I did it.

The results are shown in Table 1.

The procedure was the same as in Example 1 except that the preform was molded according to the time chart shown in Table 1 and FIG. 6. In addition, hot water is 88°
I used one from C. The results are shown in Table 2. weight percentage,
The symbols have the same meanings as in Table 1.

(Left below) ◎... No deformation ○... Mouth and neck 0.05mm or less at the bottom
0.5mm or less Δ...For mouth and neck 0.05-0.1mm bottom
0.5-1.0mm ×...For mouth and neck 0.1mm or more at the bottom
1.0 mm or more (Example 2) A container shown in FIG. 1B was manufactured.

Using the metaxylylene diamine adipate resin as the oxygen barrier resin and using the molding machine shown in FIG. A shaped container is obtained.

Therefore, it is possible to heat and fill the container without impairing its independence and to keep the container capacity constant at all times, making it possible to use the container for beverages that require heating and filling.

[Brief explanation of drawings]

Figures 1A and B are sectional views of a stretch blow molded container, Figure 2 is a sectional view of essential parts of an injection molding machine, Figure 2B is an injection molding time chart, and Figure 3 is a sectional view of a preform.
FIG. 4 is an explanatory diagram of the bottom shape of the stretch blow, FIG. 5 is a sectional view of the main part of the injection molding machine for manufacturing the container shown in FIG. 1B, and FIG. 6 is a time chart. (1) Stretch blow molded container (11) Polyethylene terephthalate (12)
... Heat-resistant resin (13) ... Oxygen barrier resin (1a) ... Mouth and neck (1b) ... Shoulder (1
c)... Body part (1d)... Bottom part 2nd figure A 111213 time t4t5t6 figure 2B figure 5 timetable figure

Claims (2)

[Claims] (1) In a stretch blow-molded container consisting of a neck, shoulders, body, and bottom, the body is made of polyethylene terephthalate, and the bottom is made of a laminated structure of polyethylene terephthalate and a heat-resistant resin with a heat distortion temperature of 100°C or higher. A stretch blow molded container characterized by: (2) In a stretch blow-molded container consisting of a neck, shoulders, body, and bottom, the body is made of a laminated structure of polyethylene terephthalate and oxygen barrier resin, and the bottom is made of polyethylene terephthalate, oxygen barrier resin, and heat barrier resin. A stretch blow-molded container characterized by being made of a laminated structure of heat-resistant resin with a deformation temperature of 100° C. or higher.