JPH08164557A - Polycarbonate container, as well as method and device for molding the container - Google Patents

Abstract

PURPOSE: To prevent burst or extremely uneven thickness by molding a preform for a polycarbonate container by blow molding at above a specified temperature of an outer surface immediately before the blow molding. CONSTITUTION: A polycarbonate container 10 is formed out of a polycarbonate resin by injection stretch blow molding. The polycarbonate container has a circular shape in cross section consisting of a neck part 14 including a mouth 12 at an upper end, a shoulder part 16 which is continued from the neck part 14 and gradually expands, a barrel part 18 which is continued from the shoulder part 16 and extends downward, and a bottom 20 at the lower end which is continued from the barrel part 18. Here, temperature of an outer surface of a preform immediately before blow molding is made to be 180 deg.C or above, the temperature of the preform is heightened so as to easily expand the whole, so that uneven thickness is restrained, thickness distribution is almost uniformed, and defective molding such as burst can be eliminated. In this case, when the temperature is below 180 deg.C, distribution of thickness is unstable and thickness is largely uneven, which are undesirable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for molding a polycarbonate container and a polycarbonate container, and more particularly to a method and apparatus for molding a large polycarbonate container by injection stretch blow molding and a polycarbonate container.

[0002]

2. Description of the Related Art Polycarbonate is generally used as a molding material for containers because of its impact resistance, transparency and dimensional stability.

In particular, it is used as a 5 gallon (about 20 liter) mineral water refillable bottle.

This 5 gallon polycarbonate container
The mainstream is formed by extrusion blow molding.

In this extrusion blow molding, a tubular parison is extruded by extrusion blow molding, and this tubular preform is sandwiched between molds for blowing.

[0006]

In the conventional extrusion blow-molded polycarbonate container, since the extrusion-blow-molded tubular parison is sandwiched between the molds and blow-molded, the parting line of the mold is Burrs will occur along the line. In addition, the moldability of the mouth and bottom of the container is not very good, and it is not preferable in terms of appearance.Furthermore, since there is a mold parting line at the bottom, there is a crack from the parting line due to a drop impact or the like. There was a problem that it was likely to occur.

Therefore, it is conceivable to mold the polycarbonate container by injection stretch blow molding which does not cause the above-mentioned problems caused by extrusion blow molding.

However, as compared with polyethylene terephthalate (PET), which is often used for injection stretch blow molding, polycarbonate has poor stretching characteristics and the degree of stretching due to a partial temperature difference is extremely different, making molding difficult. There was a problem that was.

In particular, in the case of a container having a large draw ratio, that is, a container having a narrow mouth and a large barrel shape, if the preform has an uneven temperature distribution during the expansion by blow molding or the like,
Only the high temperature part extends and the other part stops expanding, and in the worst case, it bursts.

It has been confirmed that such molding defects such as unevenness of elongation during blowing tend to appear when molding the preform having a wall thickness of about 4 mm or more.

Normally, the preform is prevented from becoming thick by making the longitudinal length of the preform as long as possible, but it is a large bottle having a narrow mouth and a barrel shape, and the thickness of the bottle is further thick. In the case of molding, there was a problem that the wall thickness of the preform inevitably exceeded 4 mm, resulting in molding defects such as uneven elongation.

On the other hand, in order to improve the wall thickness distribution,
Blow molding was performed with the temperature of the preform as low as possible, but there was a problem in that the uneven thickness would not be corrected and some of the pieces would burst.

The present invention has been made in view of the above-mentioned problems, and an object thereof is to form a polycarbonate container having a large draw ratio without causing rupture or large uneven thickness. (EN) It is possible to provide a polycarbonate container molding method, a molding apparatus therefor, and a polycarbonate container.

[0014]

In order to achieve the above object, the method according to the first invention is a method for molding a polycarbonate container, wherein the injection-molded polycarbonate preform is blow-molded to form a container. The preform has an outer surface temperature of 18 immediately before blow molding.
It is characterized by being blow molded at 0 ° C or higher.

In addition to the method of the first aspect of the present invention, the method of the second aspect of the present invention is characterized in that the injection-molded preform is heated from the outside of the preform while retaining heat inside, and then blow-molded. I am trying.

The method according to the third invention is characterized in that, in addition to the second invention, the heating from the outside of the preform is performed by radiant heat of far infrared rays from the inner wall surface of the cylindrical heating pot. .

The method according to the fourth aspect is characterized in that, in addition to the third aspect, before the blow molding, a rod-shaped heating member is inserted inside the preform and heated by radiant heat from the inside of the preform. I am trying.

In the method according to the fifth invention, in addition to the first invention, the injection molding step of the preform is carried out separately for a first molding die and a second molding die. In the first molding die, the first layer is injection-molded, and in the second molding die, the second layer is injection-molded outside the first layer. It is performed by radiant heat from heating members provided inside and outside, and the set temperature of this heating member is set higher in the inside heating member than in the outside heating member.

The method according to the sixth invention is characterized in that, in addition to the first invention, the preform is blow-molded by heating the outer surface temperature immediately before blow molding to 200 to 220 ° C.

The method according to the seventh invention is characterized in that, in addition to the first invention, in the injection molding step of the preform, the preform is molded into a body wall thickness of about 4 mm or more.

A method according to an eighth aspect of the present invention is a method for molding a polycarbonate container in which the injection-molded polycarbonate preform is blow-molded to form a container.
It is characterized by introducing blow air set to a pressure of m ² or less and performing blow molding.

The method according to the ninth invention is characterized in that, in addition to the eighth invention, the pressure of blow air introduced into the preform is set to 4 to 5 kg / cm ² .

The method according to the tenth invention is characterized in that, in addition to the first invention, the pressure of the blow air introduced into the preform in the blow molding step is set to 4 to 5 kg / cm ² . .

The method according to the eleventh aspect of the present invention is the method for molding a polycarbonate container in which the injection-molded polycarbonate preform is blow-molded to form a container, wherein blow air is blown into the preform in a blow molding step. The pressure inside the preform being introduced is about 2 kg / cm
It is characterized in that it is ^2.

According to a twelfth aspect of the present invention, in the method for molding a polycarbonate container in which the injection-molded polycarbonate preform is blow-molded to form a container, in the heating step before the blow-molding step, the outer surface temperature is When the preform is heated to 180 ° C. or higher, the preform is molded using a polycarbonate resin that does not extend in the axial direction by its own weight.

According to a thirteenth aspect of the present invention, in the apparatus for molding a polycarbonate container in which the injection-molded polycarbonate preform is blow-molded to form a container, the preform having a body wall thickness of about 4 mm or more is used. Injection molding section for injection molding, a heating section for heating the preform until the outer surface temperature immediately before blow molding reaches 180 ° C. or more, and stretching the heated preform at an introduction blow air pressure of 7 kg / cm ² or less. A blow molding part for performing blow molding to form a product, a product take-out part for taking out a molded product molded by the blow molding part, and a preform carrying part for carrying the preform to each part. I am trying.

According to a fourteenth invention, in addition to the thirteenth invention, the injection molding section has a first molding die and a second molding die, and the first molding die is provided. Includes a first injection cavity mold having an inner wall surface for injection molding a first layer on the inside of the preform, and a second molding die for injection molding a second layer on the outside of the preform. The first injection cavity mold has a second injection cavity mold having an inner wall surface having a diameter larger than that of the first injection cavity mold.

In addition to the thirteenth invention, the apparatus according to the fifteenth invention is characterized in that the heating section has inner and outer heating members for heating the preform from inside and outside by radiant heat, and the inner heating member is for outside heating. The feature is that the temperature is set higher than that of the member.

According to a sixteenth invention, in addition to the fifteenth invention, the outer heating member has a heater wound around its outer periphery,
It is composed of a cylindrical heating pot whose inner surface is subjected to far-infrared treatment, and the inner heating member is composed of a heating core which extends in the preform axial direction and has a plurality of stages of temperature controllable heaters in the axial direction. It is characterized by that.

A container according to a seventeenth aspect of the present invention is the container according to any one of the first to first aspects.
It is characterized by being molded by using any one of the molding methods according to the second invention.

The container according to the eighteenth invention is characterized in that, in addition to the seventeenth invention, it has a narrow mouth and a large diameter.

[0032]

In the first aspect of the present invention, the outer surface temperature of the preform immediately before blow molding is 180 ° C. or higher,
By increasing the preform temperature to make it easier to expand, uneven thickness can be suppressed, the thickness distribution can be made almost uniform, and molding defects such as rupture can be eliminated. In this case, 180
If the temperature is less than 0 ° C, the thickness distribution is not stable, and the uneven thickness is large, which is not preferable.

According to the second aspect of the present invention, the injection-molded preform is heated from the outside and blow-molded while retaining the heat quantity inside, thereby shortening the heating time and shortening the molding cycle. You can

Further, by heating from the outside of the preform, temperature unevenness during injection molding is eliminated, uneven thickness during blow molding is prevented, and heating from the outside facilitates blow molding of the entire preform. You can

In the third invention, the preform is heated from the outside by the radiant heat from the far infrared rays from the inner wall surface of the cylindrical heating pot, so that the temperature unevenness at the time of injection molding is eliminated and the bias of blow molding is eliminated. It is possible to prevent meat and improve heating efficiency by heating with far infrared rays.

In the fourth invention, in addition to heating from the outside of the preform, a rod-shaped heater is inserted inside the preform, and heating is performed by radiant heat from the inside of the preform, thereby further preforming the preform. It can be easily stretched during blow molding and the wall thickness distribution can be made uniform.

According to the fifth aspect of the invention, in the preform injection molding step, the first layer is injection-molded by the first molding die, and the second layer is formed on the outside of the first layer by the second molding die. By injection molding the second layer and setting the set temperature of the inner heating member higher than that of the outer heating member when heating with radiant heat from the heating members provided inside and outside the preform, injection molding is performed. It is possible to suppress the temperature unevenness of the preform as much as possible and mold it to a thick wall, and it is possible to shorten the molding cycle. In addition, by inserting the core mold twice and heating the inner side, which has become colder than the outer side, at a temperature higher than the outer side, it is possible to balance the temperature difference between the inside and outside of the preform. Moldability can also be improved.

In the sixth aspect of the present invention, the temperature range of the outer surface of the preform where the thickness distribution is easy to take is 180 to 230.
A test result of 0 ° C is obtained, preferably 200-
By setting the temperature to 220 ° C., the thickness distribution becomes stable, and molding can be performed in a state with less uneven thickness.

According to the seventh aspect of the present invention, the thickness of the body of the preform is set to about 4 mm or more, and the outer surface temperature of the preform immediately before blow molding is set to 180 ° C. or more to perform blow molding to increase the thickness. Even the preform of (1) can be molded in a state where uneven thickness is prevented.

In the eighth aspect of the invention, if the preform has temperature unevenness, the stretching tends to proceed only in the high temperature portion during blow molding, and in this case, when a rapid expansion is attempted at a high pressure, The high temperature part expands and bursts. Therefore, by introducing blow air whose set pressure is set to 7 kg / cm ² or less and slowly blow molding, the expanded part cools and synchronizes with other parts. While expanding, it is possible to eliminate the rupture at the time of blow molding and to make the thickness distribution uniform.

In the ninth invention, by setting the pressure of the blow air introduced into the preform to 4 to 5 kg / cm ² , it is possible to obtain even better moldability.

According to the tenth aspect of the invention, when the preform is heated to a high temperature of 180 ° C. or higher, the pressure of blow air introduced into the preform is 4 to 5 kg / cm ^2.
By setting to 1, it is possible to eliminate the rupture of the preform under a high temperature condition and to make the wall thickness distribution uniform to obtain good moldability.

In the eleventh aspect of the invention, the pressure in the preform when introducing the blow air into the preform is set to about 2 kg / cm ² , whereby the preform is prevented from bursting and the thickness distribution is made uniform. And good moldability can be obtained.

In the twelfth aspect of the invention, when the preform is heated to 180 ° C. or higher, the polycarbonate resin which does not stretch in the axial direction due to its own weight is used. In the case of a homopolymer, heating down to 180 ° C or higher causes drawdown, and the length of the preform changes during the heating process, causing a problem that the temperature distribution in the axial direction cannot be set at a desired position. However, it becomes possible to set the temperature distribution in the axial direction at a desired position by using the polycarbonate resin as described above.

Further, the homopolymer polycarbonate resin has particularly poor stretching characteristics, and if there is temperature unevenness, only the high temperature portion will grow very easily. At the time of molding, the molecules of the resin pull each other and try to stretch uniformly, so that the wall thickness distribution can be improved.

Further, if the preform is drawn down before blow molding, the preform may come into contact with the bottom mold and become a defective product when it is conveyed from the heating section to the blow molding section. However, there is a problem in that the distal end of the stretching rod is displaced due to a moment during the transportation, resulting in uneven thickness. However, these problems can be solved by using the above-mentioned polycarbonate resin.

In the thirteenth invention, the thickness of the body is 4
injection molding part for injection molding a preform of mm or more,
Outer surface temperature of 180 ℃ just before blow molding preform
Heating part to heat up to above and introduction blow air pressure 7
By constructing a molding apparatus for a polycarbonate container, a blow molding unit that performs stretch blow molding at a pressure of not more than kg / cm ² , a product take-out unit that takes out a molded product, and a preform transport unit that conveys a preform to each unit Molding can be performed while suppressing uneven thickness without rupturing the container.

In the fourteenth invention, a first molding die for injection molding the first layer on the inner side of the preform, and a second molding die for injection molding the second layer on the outer side. By configuring the injection molding part with, the molding cycle can be shortened,
Moreover, a thick preform can be injection-molded without causing temperature unevenness.

In the fifteenth aspect of the present invention, the heating section is provided with an inner and outer heating member for heating the preform from inside and outside by radiant heat, and the inner heating member is set to a higher temperature than the outer heating member. It is possible to eliminate the temperature unevenness of the preform during injection molding and prevent uneven thickness during blow molding.

In the sixteenth invention, the outer heating member is constituted by a heating pot, the inner heating member is constituted by a heating core, and the far-infrared treatment is applied to the inner surface of the heating pot, whereby the preform is processed. Efficient heating can be performed and the molding cycle can be shortened.

In the seventeenth invention, by molding the polycarbonate container using the molding method according to any one of the first to twelfth inventions, there is no burr and the moldability of the mouth and bottom of the bottle is reduced. It is possible to obtain a polycarbonate container which has good quality and does not easily crack at the bottom.

According to the eighteenth invention, it is possible to obtain a polycarbonate container which is molded well without rupturing a polycarbonate container having a narrow mouth and a large body diameter and preventing uneven thickness.

[0053]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described in detail below with reference to the drawings.

1 to 6 are views showing an embodiment of the present invention.

First, a polycarbonate container according to one embodiment of the present invention will be described with reference to FIG.

This polycarbonate container 10 is molded by injection stretch blow molding of a polycarbonate resin, and has a neck portion 14 including a mouth portion 12 at the upper end.
A shoulder portion 16 continuously and gradually expanding from the neck portion 14, a body portion 18 continuously extending downward from the shoulder portion 16, and a bottom portion 20 continuous from the body portion 18 at a lower end position. It has a circular cross section.

Further, this polycarbonate container 10 is
The mouthpiece 12 has a small diameter and the body portion 18 has a large diameter, and is formed as a small, large-diameter, large-body, 5 gallon (about 20 liter), refillable bottle for mineral water.

Further, the body portion 18 is formed with a reinforcing portion 24 composed of a plurality of annular inclined portions 22, and the body portion 18 when filled with contents such as mineral water is used.
It is designed to prevent deformation.

Further, an upper bottom portion 26 is formed on the bottom portion 20 so as to project inward of the container, and an annular grounding portion 28 is formed on the outer periphery of the upper bottom portion 26. The annular grounding portion 28 makes the container self-supporting. In addition, the upper bottom portion 26 prevents the contents of the bottom portion 20 from being deformed by the weight.

By forming such a polycarbonate container 10 by injection stretch blow molding, there is no burr and the moldability of the mouth portion 12 and the bottom portion 20 is better than in the conventional case of molding by extrusion blow molding. And then the bottom 2
It is possible to obtain a polycarbonate container 10 in which cracking is unlikely to occur, the thickness distribution is stable, and there is no uneven thickness.

Next, a molding apparatus for molding the above-mentioned polycarbonate container 10 will be described with reference to FIGS.

This molding apparatus performs injection stretch blow molding, and as shown in FIG. 6, an injection molding section 30 having a first molding die 50 and a second molding die 52, and a heating section 32. A blow molding section 34, a product unloading section 36, and a preform carrying section 38.

The preform transport section 38 transfers the preform 56 (see FIGS. 4 and 5) from the injection molding section 30 to the heating section 3.
2, the blow molding section 34, and the product unloading section 36 are circulated and conveyed, and the neck portion 14 of the preform 56 (see FIG.
Neck mold 40 made of split mold for holding (see 3, 4, 5)
And a neck die support member 44 composed of a pair of split plates 42 that support the neck die 40 so that the neck die 40 can be opened and closed. The neck die support member 44 includes a first molding die 50 and a second molding die 5 of the injection molding unit 30.
2. The preform 56 is provided on the lower surface of the rotary transport plate 46 at a position corresponding to the heating unit 32, the blow molding unit 34, and the product unloading unit 36, and the preform 56 is rotated by a predetermined angle, for example, 72 degrees. First of the injection molding section 30
From the molding die 50 to the second molding die 52, the heating unit 32,
The blow molding unit 34 and the product take-out unit 36 are circulated and conveyed.

The rotary carrier plate 46 is rotatable on the lower surface of the upper substrate 48.

The injection molding part 30 is for molding a polycarbonate resin by injection molding to form a cylindrical preform having a bottom. As shown in FIGS. 2 and 3, the first molding die 50 has a first molding die 50. Injection cavity mold 50a and first injection core 54
a, and the second molding die 52 includes a second injection cavity mold 52a and a second injection core 54b.

The first injection cavity mold 50a has an inner wall surface 60 having a slightly smaller diameter for injection molding the first layer (see FIG. 2) 58 inside the preform 56.

The second injection cavity mold 52a is used for injection molding the second layer (see FIG. 3) 62 on the outer side of the preform 56 and has a diameter larger than the inner wall surface 60 of the first molding die 50. It has an inner wall surface 64 having a diameter. The second injection cavity mold 52a is set so that the thickness of the body portion 66 of the preform 56 is finally about 4 mm or more.

Thus, the first molding die 50 and the second molding die 50
The molding die 52 of the first layer 58 and the second layer 62
By performing injection molding in two stages, the molding cycle can be shortened, and temperature unevenness during injection molding of the thick preform 56 can be suppressed.

First and second injection cores 54a, 54b
From the upper substrate 48 to the upper substrate 48 and the rotary transport plate 4.
6 is inserted into the first injection cavity mold 50a and the second injection cavity mold 52a through 6 and can be retracted from the rotary transport plate 46 after the completion of injection molding. The injection cores 54a and 54b have the same shape and size.

The heating section 32 heats the preform 56 from inside and outside by radiant heat. As shown in FIG. 4, the heating unit 32 has a cylindrical heating pot 6 for heating the preform 56 from outside.
8 and a rod-shaped heating core 70 for heating the preform 56 from the inside.

The heating pot 68 includes five ring-shaped heating blocks 74a, 74b, 7 having a heater 72 wound around the outer periphery thereof.
4c, 74d, 74e are vertically stacked, and each heating block 74a, 74b, 74c, 7
Far infrared rays are applied to the inner surfaces of 4d and 74e. Further, in the heating section 32, the outer surface temperature of the preform 56 immediately before the blow molding is 18%.
This heating pot 6 is used to heat it up to 0 ° C or higher.
8 heating blocks 74a, 74b, 74c, 7
As shown in Table 1, the preferable set temperature ranges of 4d and 74e are 250 to 350 ° C., respectively.

[0072]

[Table 1]

The heating core 70 penetrates the upper substrate 48 and the rotary transfer plate 46 from above the upper substrate 48 and then the preform 5 is formed.
6 can be inserted into the center of the rotary conveyor plate 4 after heating.
It is possible to evacuate from 6. Further, the heating core 70 contains a rod-shaped heater 76 capable of temperature control in three stages extending in the axial direction of the preform 56, and three stages of heating rings 78a, 78b, 78c arranged in the outer circumferential axial direction thereof. The temperature of the preform 56 can be controlled in three stages in the axial direction through the heating rings 78a, 78b, 78c. Further, in the heating core 70, the injection cores 54a and 54b are subjected to two injection moldings by the first molding die 50 and the second molding die 52 at the time of injection molding.
Are contacted with each other and the inside of the preform 56 is cooled more than the outside, so heating is performed at a set temperature higher than the set temperature of the heating pot 68. This heating core 70
As shown in Table 2, a preferable actually measured temperature range in
The heating ring 78a is 400 to 500 ° C., the heating ring 78b is 500 to 600 ° C., and the heating ring 7 is
In 8c, it is 500-600 degreeC. In addition,
Also in the heating core 70, heating using radiant heat by far infrared rays is performed.

As described above, the preform 56 is heated by the radiant heat from inside and outside of the heating pot 68 and the heating core 70, and the set temperature of the inner heating core 70 is set to the heating pot 6.
By setting the temperature higher than the set temperature of 8, it is possible to eliminate temperature unevenness of the preform 56 during injection molding, prevent uneven thickness during blow molding, and heat the heating pot 68.
By performing the far infrared treatment on the inner surface of the preform 56, the preform 56 can be efficiently heated and the molding cycle can be shortened. In addition, preform 56
It is possible to eliminate temperature unevenness during injection molding and prevent uneven thickness during blow molding.

[0075]

[Table 2]

The blow molding section 34 performs stretch blow molding on the preform 56 heated to an outer surface temperature of 180 ° C. or higher in the heating section 32 to mold it into a product shape. And the blow core 82
And a stretching rod 84.

The blow mold 80 has an inner wall surface 86 corresponding to the shape of the product polycarbonate container 10,
In addition, an upper bottom mold 88 for molding the upper bottom portion 26 of the polycarbonate container 10 is provided in the lower portion.

The blow core 82 penetrates the upper substrate 48 and the rotary transfer plate 46 from above the upper substrate 48 and the neck mold 40.
Blow air is introduced from the blow core 82 into the preform 56 held by the neck mold, and a stretch rod 84 penetrating the blow core 82 is extended downward to blow mold the preform 56. Blow molding is performed by closely contacting the inner wall surface 86 of the mold 80.

Further, during the blow molding, if the preform 56 has temperature unevenness, the stretching tends to proceed only in the high temperature portion, and when the preform 56 is rapidly expanded at a high pressure, the high temperature portion expands. As a result, the blown air is blown at a set pressure of 7 kg / cm ² or less, and slowly blow-molded, so that the stretched part cools and expands in synchronization with other parts. As a result, rupture during blow molding can be eliminated and the wall thickness distribution can be made uniform. In this case, by setting the set pressure to 4 to 5 kg / cm ² and restricting the flow rate of the blow air, good moldability can be obtained during slow blow molding, and the preform 5 at that time can be obtained.
The pressure inside 6 is about 2 kg / cm ² , and the preform 56 is heated to such a high temperature that it expands with this level of internal pressure.

Further, from the time when the blow air is introduced until the preform 56 is completely adhered, the internal pressure is 2 kg / c.
It is preferable to introduce the blow air having a set pressure of about 17 kg / cm ² for forming the shape after maintaining the pressure at about m ² and completely adhering to shape.

After the blow molding is completed, the blow core 82
The stretching rod 84 and the stretching rod 84 can be retracted from the rotary transport plate 46.

The product take-out portion 36 has a neck-type support member 44.
The dividing plate 42 constituting the above is separated by a cam member (not shown), and the neck mold 40 is opened to release the holding state of the neck portion 14 of the polycarbonate container 10 so that the polycarbonate container 10 can be taken out of the molding apparatus. ing.

Next, a method of molding the polycarbonate container 10 using the above-described molding device will be described.

First, in the injection molding section 30, the neck mold 40 is arranged with respect to the first injection cavity mold 50a of the first molding die 50, and the injection core 54a is further inserted, and this first injection cavity is inserted. The molten polycarbonate resin is injected into the mold 50a to mold the first layer 58.

Next, the first layer 58 is released from the first injection cavity mold 50a, and the neck mold 40 is placed in the second injection cavity mold 52a of the second molding die 52 to form the second mold. Put the first layer 58 in the injection cavity mold 52a,
After inserting the injection core 54b, the molten polycarbonate resin is injected into the second injection cavity mold 52a,
By molding the second layer 62 on the outside of the first layer 58,
The preform 56 having a thickness of the body portion 66 of about 4 mm or more, for example, 13 mm is formed.

As described above, the first molding die 50 and the second molding die 50
The preform 5 is divided into two stages using the molding die 52 of
By injection-molding No. 6, it is possible to shorten the molding cycle, and it is possible to injection-mold a thick preform without causing temperature unevenness.

After cooling the preform 56 to a state where it can be released from the mold in the second injection cavity mold 52a, the preform 56 is taken out from the second injection cavity mold 52a, and the neck mold 40 becomes the neck portion 14 of the preform 56. While maintaining the above, the rotary transport plate 46 is rotated by a predetermined angle to transport the preform 56 to the heating unit 32.

In the heating section 32, the preform 56 is placed in the cylindrical heating pot 68, the heating core 70 is placed in the center of the preform 56, and the radiant heat is generated from the inside and outside of the preform 56 in a non-contact state. Preform 5
6 is heated so that the outer surface temperature of the preform 56 immediately before blow molding becomes 180 ° C. or higher.

In this case, as shown in Table 1, the set temperature conditions of the heating blocks 74a, 74b, 74c, 74d, 74e of the heating pot 68 are, for example, 300 ° C., 2 ° C. in the first heating block 74a from the top. Step heating block 74
280 ° C in b, 28 in the third heating block 74c
The heating is performed at 0 ° C., 300 ° C. in the fourth heating block 74 d, and 310 ° C. in the fifth heating block 74 e.

Further, the heating ring 78a of the heating core 70,
As shown in Table 2, the set temperature conditions of 78b and 78c are as follows.
For example, at the measured temperature, the upper 78a is 450 ° C., the middle heating ring 78b is 510 ° C., and the lower heating ring 78c is 5 ° C.
Set at 10 ° C. and heat.

In this way, the temperature of the heating core 70 is set higher than the temperature of the heating pot 68, and the inside of the cooled preform 56 is heated more than the outside in the injection molding process to make the temperature uniform. I am trying.

The heating time is about 15 seconds.

After the heating of the preform 56 by the heating pot 68 and the heating core 70 is completed, the preform 56 is
The heating core 70 is removed from the inside, the preform is taken out from the heating pot 68, the rotary conveying plate 46 is rotated by a predetermined angle, and the preform 56 is transferred to the blow molding part 34 with the neck part 14 held by the neck mold 40. And carry.
In this case, if the polycarbonate resin is a homopolymer, drawdown starts when heated to 180 ° C. or higher, the length of the preform 56 changes during heating, and the temperature distribution in the axial direction can be specified at a desired position. It may disappear. Further, if there is temperature unevenness, only the high temperature portion may be stretched very easily. Therefore, when the preform 56 is heated to 180 ° C. or higher before blow molding, the preform 56 uses a polycarbonate resin that does not extend in the axial direction by its own weight, for example, a branched type polycarbonate resin, thereby preventing drawdown, At the time of blow molding, the resins pull each other and stretch uniformly, so that the thickness distribution can be improved. Further, by using such a resin, it is possible to prevent the preform 56 from coming into contact with the upper bottom mold 88 when being conveyed from the heating unit 32 to the blow molding unit 34, and to prevent defective products from occurring. It is possible to prevent the bending and bending of the tip end of the stretching rod 84 due to a moment during the transportation of the preform 56 to cause uneven thickness.

In the blow molding section 34, the blow molding die 80 is used.
Preform 56 heated to a temperature of 180 ° C or above
Is set, and the blow core 82 is inserted into the neck die 40, and the bottom portion of the preform 56 is centered at the bottom of the preform 56 by the extension rod 84 to slowly extend in the axial direction.
To 7 kg / cm ² or less, for example, blow air set to a pressure of 5 kg / cm ² is introduced at a relatively low flow rate. In this case, the pressure inside the preform 56 is about 2 kg / c.
The preform 56 is slowly expanded while maintaining it at about m ² . Further, in this case, after the blow molding die 80 is clamped, the introduction of the blow air is continued until the preform 56 comes into contact with the inner wall surface of the blow molding die 80 and the shape is fixed.

After the preform 56 is fixed to the shape of the product in the blow mold 80, the blow core 82 and the drawing rod 84 are pulled out, and the blow mold 80 is opened.
The rotation transfer plate 46 is rotated by a predetermined angle, and the polycarbonate container 10 blow-molded with the neck part 40 held by the neck mold 40 is transferred to the product unloading part 36. In the product take-out portion 36, the dividing plate 42 constituting the neck die support member 44 is separated by a cam member (not shown), the neck die 40 is opened, and the neck portion 14 of the polycarbonate container 10 is opened.
Then, the polycarbonate container 10 is taken out of the molding apparatus.

Preform 56 in such a process
The outer surface temperatures of the upper part, the middle part and the lower part were measured, and as shown in Table 3, for example, immediately before blow molding, the upper part temperature was 208 ° C, the middle part temperature was 210 ° C and the lower part temperature was 210 ° C. The temperature was 0 ° C., which was within a suitable temperature range of 180 ° C. or higher and 200 ° C. to 220 ° C. The polycarbonate container 10 molded by such a process has a thickness distribution in a preferable range in the axial direction and the circumferential direction, and is in a state where uneven thickness is hardly recognized.

[0097]

[Table 3]

The present invention is not limited to the above embodiments, but various modifications can be made within the scope of the gist of the present invention.

For example, in the above-mentioned embodiment, the preform is injection-molded in two steps by using the first molding die and the second molding die in the injection molding section, but the present invention is not limited to this example. Instead, it is also possible to injection-mold a thick preform at one time with one molding die.

Further, in the above embodiment, the heating pot and the heating core are brought into non-contact with the preform and heated by radiant heat, but the present invention is not limited to this example, and a heating means by direct contact may be used. It is possible. Further, the inner wall surface of the heating pot is subjected to far-infrared treatment so as to be heated by far-infrared radiation, but it is not always necessary to perform far-infrared treatment.

Further, in the above-described embodiment, the case where the preform is conveyed by the rotary conveying plate in the preform conveying section is shown, but the present invention is not limited to this example, and arm type and various other conveying means can be adopted.

[0102]

As described above, according to the first aspect of the invention, the outer surface temperature of the preform immediately before blow molding is 18
By setting the preform temperature to 0 ° C. or higher and increasing the preform temperature so that the entire product can easily swell, uneven thickness can be suppressed, the thickness distribution can be made substantially uniform, and molding defects such as rupture can be eliminated.

According to the second aspect of the invention, the injection-molded preform is heated from the outside and blow-molded while keeping the amount of heat inside, thereby shortening the heating time and shortening the molding cycle. There is an effect that can be.

By heating from the outside of the preform, temperature unevenness during injection molding is eliminated, uneven thickness during blow molding is prevented, and heating from the outside facilitates blow molding of the entire preform. There is an effect that can be.

According to the third invention, the preform is heated from the outside by the radiant heat of the far infrared rays from the inner wall surface of the cylindrical heating pot, so that the temperature unevenness at the time of injection molding is eliminated and the uneven thickness of blow molding is eliminated. In addition to preventing the above, there is an effect that heating efficiency can be improved by heating with far infrared rays.

According to the fourth invention, in addition to heating from the outside of the preform, a rod-shaped heater is inserted inside the preform, and heating is performed by radiant heat from the inside of the preform to further blow the preform. It has the effects of making it easier to stretch during molding and making the wall thickness distribution uniform.

According to the fifth invention, in the injection molding step of the preform, the first layer is injection-molded by the first molding die, and the second layer is formed outside the first layer by the second molding die. Two
By injection-molding the layer of, and setting the set temperature of the inner heating member higher than that of the outer heating member when heating with radiant heat from the heating members provided inside and outside the preform, It is possible to suppress the temperature unevenness of the preform as much as possible and to mold it into a thick wall, and also to shorten the molding cycle. In addition, by inserting the core mold twice and heating the inner side, which has become colder than the outer side, at a temperature higher than the outer side, it is possible to balance the temperature difference between the inside and outside of the preform. There is an effect that the moldability can also be improved.

According to the sixth aspect of the present invention, the temperature range of the outer surface of the preform where the thickness distribution is easy to take is 180 to 230 ° C.
The test result that it is obtained is preferably 200 to 2
By setting the temperature to 20 ° C., there is an effect that the thickness distribution is stable and the molding can be performed in a state with less uneven thickness.

According to the seventh aspect of the present invention, the thickness of the body of the preform is about 4 mm or more, and the outer surface temperature of the preform immediately before blow molding is 180 ° C. or more. Even a preform has an effect that it can be molded in a state where uneven thickness is prevented.

According to the eighth aspect of the invention, if the preform has temperature unevenness, the stretching tends to proceed only in the high temperature portion during blow molding. In this case, if the preform is rapidly expanded at a high pressure, the high temperature The part will expand and burst. Therefore, by introducing blow air whose set pressure is set to 7 kg / cm ² or less and slowly blow molding, the expanded part will cool and synchronize with other parts. There is an effect that it can be expanded, and as a result, rupture during blow molding can be eliminated and the thickness distribution can be made uniform.

According to the ninth aspect of the invention, by setting the pressure of the blow air introduced into the preform to 4 to 5 kg / cm ² , it is possible to obtain a better moldability.

According to the tenth invention, the preform is
By setting the pressure of the blow air introduced into the preform to 4-5 kg / cm ² when heated to a high temperature of 80 ° C or higher, the preform is prevented from bursting under the high temperature condition and the wall thickness distribution There is an effect that the moldability can be made uniform and good moldability can be obtained.

According to the eleventh invention, the pressure inside the preform when introducing blow air into the preform is about 2
The use of kg / cm ² is effective in preventing the preform from bursting, making the wall thickness distribution uniform, and obtaining good moldability. According to the twelfth invention, when the preform is heated to 180 ° C. or higher, by using the polycarbonate resin in which the preform does not extend in the axial direction by its own weight, the case of the conventionally used polycarbonate resin, particularly the homopolymer , The drawdown started by heating above 180 ° C, the length of the preform changed during the heating, and the temperature distribution in the axial direction could not be set at the desired position. By using such a polycarbonate resin, it becomes possible to set the temperature distribution in the axial direction at a desired position.

Further, the homopolymer polycarbonate resin has particularly poor stretching characteristics, and if there is temperature unevenness, only the high temperature portion will be stretched very easily. At the time of molding, the molecules of the resin pull each other and try to stretch uniformly, so that there is an effect that the thickness distribution can be improved.

Furthermore, if the preform is drawn down before the blow molding, the preform may come into contact with the bottom mold and become a defective product when it is conveyed from the heating section to the blow molding section. However, there is a problem that the stretch rod is bent due to a moment during transportation and the tip of the stretching rod is displaced, resulting in uneven thickness. However, by using the above-mentioned polycarbonate resin, these problems can be solved.

According to the thirteenth invention, the thickness of the body is 4 m.
An injection molding part for injection molding a preform of m or more, a heating part for heating the preform until the outer surface temperature immediately before blow molding reaches 180 ° C. or more, and an introduction blow air pressure 7k
By forming a molding apparatus for a polycarbonate container by a blow molding unit that performs stretch blow molding at g / cm ² or less, a product take-out unit that takes out a molded product, and a preform conveyance unit that conveys a preform to each part, a polycarbonate container is formed. There is an effect that uneven thickness can be suppressed and molding can be performed without rupturing the container.

According to the fourteenth invention, the first molding die for injection-molding the first layer on the inner side of the preform and the second molding die for injection-molding the second layer on the outer side are provided. By forming the injection molding section, there is an effect that the molding cycle can be shortened, and furthermore, a thick preform can be injection molded without causing temperature unevenness.

According to the fifteenth aspect of the invention, the heating section is provided with inner and outer heating members for heating the preform from inside and outside by radiant heat, and the inner heating member is set to a higher temperature than the outer heating member. There is an effect that uneven temperature of the preform at the time of injection molding can be eliminated and uneven thickness at the time of blow molding can be prevented.

According to the sixteenth invention, the outer heating member is constituted by a heating pot, the inner heating member is constituted by a heating core, and the far-infrared ray treatment is applied to the inner surface of the heating pot.
The preform can be efficiently heated,
There is an effect that the molding cycle can be shortened.

According to the seventeenth invention, by molding the polycarbonate container using the molding method according to any one of the first to twelfth inventions, there is no burr and the moldability of the mouth and bottom of the bottle is improved. There is an effect that it is possible to obtain a polycarbonate container that is good and is not easily cracked at the bottom.

According to the eighteenth invention, there is an effect that a polycarbonate container having a good shape can be obtained without rupturing a polycarbonate container having a narrow mouth and a large cylinder diameter, and preventing uneven thickness.

[0122]

[Brief description of drawings]

FIG. 1 is a front view of a polycarbonate container according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a state in which an inner first layer is injection-molded by a first molding die in an injection molding section.

FIG. 3 is a view of a first molding die using a second molding die in an injection molding section.
FIG. 6 is a cross-sectional view showing a state in which a second layer is injection-molded on the outside of the layer.

FIG. 4 is a cross-sectional view showing a state in which heating is performed from inside and outside of the preform in a heating unit.

FIG. 5 is a cross-sectional view showing a state in which a preform is blow-molded in a blow-molding section.

FIG. 6 is a plan view showing a preform transport unit of the molding apparatus.

[Explanation of symbols]

 10 Polycarbonate Container 14 Neck Part 18 Body of Container 30 Injection Molding Part 32 Heating Part 34 Blow Molding Part 36 Product Extraction Part 38 Preform Transfer Part 50 First Molding Die 52 Second Molding Die 56 Preform 58th 1st layer 60 Inner wall surface 62 Second layer 64 Inner wall surface 66 Preform barrel 68 Heating pot 70 Heating core 72 Heater 74 Heating block 76 Heater 78 Heating ring

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display area B29L 22:00

Claims (18)

[Claims] 1. A method for molding a polycarbonate container, comprising forming a container by blow molding an injection-molded polycarbonate preform, wherein the preform has an outer surface temperature of 1 immediately before blow molding.
A method for molding a polycarbonate container, which comprises blow molding at 80 ° C or higher. 2. The method for molding a polycarbonate container according to claim 1, wherein the injection-molded preform is blow-molded after being heated from the outside of the preform while retaining heat inside. 3. The method for molding a polycarbonate container according to claim 2, wherein the heating from the outside of the preform is performed by radiant heat of far infrared rays from the inner wall surface of the cylindrical heating pot. 4. The method for molding a polycarbonate container according to claim 3, wherein before the blow molding, a rod-shaped heating member is inserted inside the preform and heated by radiant heat from the inside of the preform. 5. The preform injection molding step according to claim 1, wherein the first molding die and the second molding die are used.
In the first molding die, the first layer is injection-molded, and in the second molding die, the second layer is provided outside the first layer. The injection-molded preform is heated by radiant heat from the heating members provided inside and outside the preform, and the set temperature of this heating member is set higher on the inside heating member than on the outside heating member. A method for molding a polycarbonate container, comprising: 6. The preform according to claim 1, wherein the outer surface temperature of the preform is 2 immediately before blow molding.
A method for molding a polycarbonate container, characterized in that it is heated to 00 to 220 ° C. and blow-molded. 7. The apparatus for molding a polycarbonate container according to claim 1, wherein the preform is molded to a body wall thickness of about 4 mm or more in the preform injection molding step. 8. A method for molding a polycarbonate container, comprising forming a container by blow molding an injection-molded polycarbonate preform, wherein a pressure of 7 kg / cm ² or less is set in the preform in the blow molding step. A method of molding a polycarbonate container, which comprises introducing blow air to perform blow molding. 9. The pressure of blow air introduced into the preform according to claim 8, which is 4 to 5.
A method for molding a polycarbonate container, wherein the method is set to kg / cm ² . 10. The method for molding a polycarbonate container according to claim 1, wherein the pressure of the blow air introduced into the preform in the blow molding step is set to 4 to 5 kg / cm ² . 11. A method for molding a polycarbonate container, wherein an injection-molded polycarbonate preform is blow-molded to form a container, wherein a pressure in the preform during introduction of blow air into the preform in a blow molding step. Is about 2 kg / cm ² and a method for molding a polycarbonate container. 12. A method for molding a polycarbonate container, wherein an injection-molded polycarbonate preform is blow-molded to form a container, wherein the outer surface temperature is 180 ° C. in the heating step before the blow molding step.
A method for molding a polycarbonate container, characterized in that the preform is molded using a polycarbonate resin that does not extend in the axial direction under its own weight when the preform is heated as described above. 13. A polycarbonate container molding apparatus for forming a container by blow molding an injection-molded polycarbonate preform, comprising: The outer surface temperature of the preform immediately before blow molding is 18
A heating part for heating to 0 ° C. or higher, and a blow air pressure of 7 kg for introducing the heated preform.
/ Cm ² or less, a blow molding part for performing stretch blow molding to mold into a product shape, a product unloading part for taking out a molded product molded by the blow molding part, and a preform carrying part for carrying the preform to each part. A molding device for a polycarbonate container, comprising: 14. The injection molding section according to claim 13, wherein the injection molding section has a first molding die and a second molding die, and the first molding die is the first inner mold of the preform. A first injection cavity mold having an inner wall surface for injection molding a layer, the second molding die having a diameter smaller than that of the first injection cavity mold for injection molding the second layer on the outer side of the preform. A polycarbonate container molding apparatus comprising a second injection cavity mold having a large inner wall surface. 15. The heating unit according to claim 13, wherein the heating unit has inner and outer heating members that heat the preform from inside and outside by radiant heat, and the inner heating member is set to a temperature higher than that of the outer heating member. A molding device for a polycarbonate container, characterized in that 16. The outer heating member is a cylindrical heating pot having a heater wound around the outer periphery and a far infrared ray treatment on the inner surface, and the inner heating member is arranged in a preform axial direction. A molding apparatus for a polycarbonate container, comprising a heating core that has a heater that extends and has a plurality of stages of temperature controllable in the axial direction. 17. A polycarbonate container molded by using the molding method according to any one of claims 1 to 12. 18. The polycarbonate container according to claim 17, which has a narrow mouth and a large diameter.