JP3014876B2 - Heat resistant container molding equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for forming a heat-resistant container.

[0002]

In general, the packaging container of the biaxially stretch blow-molded container called synthetic resin thin-walled, blow mold comprising a preform in the stretch suitable temperature obtained by injection or extrusion molding from the split mold cavity And is expanded in the longitudinal direction of the container and expanded in the lateral direction by the pressure of the gas blown into the container.

By the way, depending on the selection of the material used for the above-mentioned container, there is a problem that the body is deformed when the inside is filled in a high temperature state.

Therefore, conventionally, the blow molding process performed after temperature control of the preform is divided into primary and secondary, and the primary blow molding is performed in a longitudinal direction more than that obtained by secondary blow molding corresponding to final molding. A so-called oven blow molding method in which the primary blow molded product is shrunk by heat treatment and then subjected to secondary blow molding to obtain a container as a final molded product. Has been proposed. According to this molding method, a heat-resistant container can be obtained by thermally shrinking the primary blow molded product before the secondary blow molding.

[0005]

When such a heat treatment is performed, uniform shrinkage over the entire primary blow-molded product can be achieved by shortening the molding time in secondary blow molding by re-blowing. Furthermore, it is desired in order to achieve uniform heat resistance.

However, in practice, the temperature distribution of the preform at the stage of temperature regulation may not be maintained uniformly in the circumferential direction. Then, when a preform in which the temperature distribution in the circumferential direction is not maintained uniformly is subjected to primary blow molding, the stretch amount in the circumferential direction differs, thereby causing uneven thickness. Therefore, when the primary blow-molded product having uneven thickness is subjected to heat treatment, heat shrinkage is not uniformly performed in the circumferential direction. Further, the shrinkage in the circumferential direction may be uneven due to the directionality of the hot air in the oven, and the shrinkage ratio may be different due to the difference in the stretching ratio or thickness in the axial direction.
When such a heat-shrinkable molded product is placed in a cavity and subjected to mold clamping in order to perform secondary blow molding, a portion where uneven thickness occurs is cut into a parting surface of the mold, and the parting surface is deformed. The pinched portion may remain as a burr. Therefore, the secondary blow-molded product, which is the final molded product with burrs, has been discarded as a defective product, and the yield of the heat-resistant container may be reduced.

Accordingly, an object of the present invention is to provide a heat-resistant heat-shrinkable molded product which is placed in a cavity of a mold used for secondary blow molding in view of a problem in a conventional heat-resistant container molding apparatus. A heat-resistant container capable of preventing the formation of burrs by preventing a part of the heat-shrinkable molded product from being caught by the parting surface of the mold and preventing the yield of the final molded product from deteriorating. An object of the present invention is to provide a molding device.

[0008]

In order to achieve this object, an invention according to claim 1 is to form a primary blow-molded product by biaxially stretch-blow-molding a preform in a machine direction and a transverse direction. After shrinking the blow-molded product in a heat treatment furnace, the molding device for forming a heat-resistant container by secondary blow-molding the heat-shrinkable molded product in a cavity of a secondary blow-molding die composed of a split mold, A straightening means is provided for reducing the outer diameter of the shrink-molded product to be smaller than the outer diameter of the secondary blow-molded product.

According to a second aspect of the present invention, when the heat-shrinkable molded product is disposed inside and the mold is closed with the heat-shrinkable product, the dimension between both ends in a direction parallel to the parting surface of the mold is adjusted. It is characterized in that it is made smaller as an object.

According to a third aspect of the present invention, the straightening means is provided so as to be able to advance and retreat with respect to the inside of the heat treatment furnace. A straightening guide member sized to reduce the dimension in the direction is provided.

According to a fourth aspect of the present invention, there is provided means for maintaining the internal pressure of the primary blow molded article at a predetermined pressure during the heat shrink molding, and this means comprises at least a part of the increase in the internal pressure during the correction of the heat shrink molded article. Alternatively, a relief member is provided for eliminating the entirety.

[0012]

According to the present invention, since the outer diameter of the heat-shrink molded article is corrected to be smaller than the outer diameter of the secondary blow molded article before the secondary blow molding, the parting surface of the secondary blow molding die is corrected. The outer portion of the heat-shrinkable molded product is not located at the same time.
Therefore, even if the secondary blow-molded product, which is the final molded product by secondary blow molding, presents a state in which the outer diameter is biased due to the difference in the amount of shrinkage in the heat treatment stage, the secondary molding die is It is not trapped by the parting surface.

Further, according to the present invention, when the heat-shrinkable molded product is corrected to be smaller than the inner size of the secondary blow molding die, the internal pressure rises, and the rise in the internal pressure is increased via the relief member. Since the heat-shrinkable molded product is removed, the heat-shrinkable molded product is smoothly corrected without being hindered by an increase in the internal pressure.

[0014]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

FIG. 1 shows a molded product to which a molding apparatus according to the present invention is applied.
Prior to the secondary blow molding of the biaxial stretch blow molding, the primary blow molded product is subjected to heat shrinkage in a heating furnace to obtain a heat-resistant molded product by oven blow molding.

That is, the details of the oven blow molding are described in, for example, Japanese Unexamined Patent Publication No.
As described in the specification of JP-A-205124 and JP-A-3-234520, for example, a preform at an appropriate stretching temperature which is injection- or extrusion-molded using polyethylene terephthalate (hereinafter abbreviated as PET). After the temperature of 80 is controlled, each step for obtaining a primary blow molded product 90, a heat shrink molded product 100, and a secondary blow molded product 110 is provided.

The primary blow-molded product 90 is stretched in the vertical direction while vertically guiding the container while centering and guiding by a stretchable stretch rod (not shown) inserted from the neck of the preform 80. The lateral expansion molding is performed by blowing out a pressurized fluid, for example, air.

Further, the heat-shrinkable molded product 100 is 180 to 2
By heating the primary blow molded product 90 in an atmosphere of 20 ° C., the primary blow molded product 90 is thermally contracted in the vertical and horizontal directions. Then, the heat-shrinkable molded product 100
Is formed to have a height substantially the same as or slightly higher than the final molded product, and to have a smaller lateral dimension than the final molded product. Further, in the secondary blow molded product 110, the heat shrink molded product 100 is positioned in a blow mold cavity formed to the size of the final molded product, and the heat shrink molded product 100 is stretched in the lateral direction by introducing air. Obtained.

On the other hand, FIG. 2 is a plan view showing an oven blow stage 20 when the molding apparatus of the present invention is applied to the oven blow molding machine 10. The turntable 22 is provided on the machine base. The turntable 22 is provided by a machine base so as to be intermittently rotatable in the direction of the arrow shown in the figure, and is a primary blow molded product along the rotation direction of the turntable 22.
9 0 transfer station 12 having a carrying path 12A of the removal station 14 is located with a discharge channel 14A of the secondary blow-molded article 11 0, between each of these stations, to heating stations 24A of the first to fifth 2
4E are arranged. Further, a secondary blow molding station is provided behind the fifth heating station 24E, and a mold clamping device 30 having a blow mold formed of a split mold is disposed in this station.

The rotary disk 22 is provided with a structure for holding the molded product while moving to each station. This structure includes, for example, a clamping mechanism described in Japanese Patent Application Laid-Open No. 3-234520. A member is provided. In the case of the present embodiment, for example, four holding members are provided along the circumferential direction of the turntable 22 as one block.
The transfer station 12 and the take-out station 14 are provided with a supply device 16 and a take-out device 18 that can reciprocate with the turntable 22 respectively.

The first to fifth heating stations 24A to 24E are provided for forcibly flowing hot air along the longitudinal direction of the primary blow-molded article 90 so as to contact the body of the primary blow-molded article 90. Among the heating stations, the heating furnace 240 of the fifth heating station, which is provided on the front side of the mold clamping device 30 and opposed to the bottle width correcting device 40 described later, has a structure thereof. This is shown in FIG.

That is, the fifth heating station 24E
Is formed in a double structure having an inner space 240B and an outer space 240C which are open at the top and partitioned inside by a partition 240A. Each space described above is connected to the hot air generator 240F via ventilation pipes 240D and 240E in the figure, and the spaces are communicated by opening the upper part of the partition 240A.

The hot air generator 240F is attached to a side of the manufacturing apparatus 10, and the hot air from the hot air generator 240F is supplied to the ventilation pipe 240 connected to the inner space 240B.
D, and blows out from the lower part of the inner space 240B, and then through the communicating position at the upper part of the partition 240A, the outer space 2B.
It returns to the hot air generator 240F via 40C.

A shape for guiding hot air along the outer periphery of the body of the primary blow molded product 90 is set below the bottom of the primary blow molded product 90 suspended in the space below the inner space 240B. Baffle member 240 with dish-shaped cross section
G is disposed to prevent the hot air blown from the hot air generator 240F from being directly blown to the bottom of the primary blow molded product 90.

Further, at a position of the partition wall 240A facing the shoulder of the primary blow molded article 90, a guide extended toward the inside space at an angle corresponding to the inclination of the shoulder. A plate 240H is provided, and the inner space 2 is provided.
The hot air flowing from the lower part of 40B is blown to the primary blow molded product 9
It is designed to move along the zero shoulder portion.
In addition, this guide plate 240H has
A, and the tip is separated from the shoulder of the primary blow molded article 90 so that hot air flows between the tip and the shoulder. Guide plate 2
The hot air that has passed between the tip of 40H and the shoulder of the primary blow molded article 90 flows from the communicating portion of the partition 240A toward the outer space 240C, and is collected by the hot air generator 240F.

The outer wall of the heating furnace 240 and the partition 2
An opening 240I is formed in the opening 40I.
Is provided with a bottle width straightening device 40 provided with a straightening guide 42 capable of moving forward and backward with respect to the inside of the heating furnace 240. The first to fourth heating stations 2
4A to 24D, the heating furnace disposed in the opening 2
Except that 40I is not provided, the configuration is the same as that of the heating furnace provided in the fifth heating station 24E.

On the other hand, the bottle width correcting device 40 is a device that is a feature of the present embodiment, and the outer diameter of the heat-shrinkable molded product heat shrunk in the heating furnace 240 is smaller than the outer diameter of the secondary blow-molded product. It is provided in order to.

As shown in FIG. 4, the bottle width straightening device 40 includes a straightening guide 42 and a driving unit for driving the straightening guide 42 into and out of the heating furnace 240,
A relief mechanism 46 for eliminating an increase in the internal pressure of the heat-shrinkable molded product 100 is provided as a main component.

Referring to FIG. 4, the bolt width correcting device 40 includes:
A straightening guide 42 for pressing the side surface in the arrangement direction of the heat-shrinkable molded product 100 formed by the heat treatment in the heating furnace 240;
And a drive unit for moving the straightening guide 42 toward the heat-shrinkable molded article 100.

In the arrangement direction of the heat-shrinkable molded products 100 suspended in the holding member by the holding member, the straightening guide 42 is used when the heat-treated molded products 100 are arranged inside and the split molds are clamped. The surfaces at both sides in the direction parallel to the bearing surface are arranged with an arrangement interval at which they can abut. Then, the correction guide 42 has a base member having a sliding member 44.
, And a distal end extending toward the opening 240I of the heating furnace 240 is formed with a tapered surface in a plan view shape. Also, the vertical shape at the tip is
As shown in part in FIG. 5, the upper part is formed with a slope surface along the shape of the shoulder part of the secondary blow molded article 110, and the lower part is similar to the shape of the heel part of the secondary blow molded article 110. A round portion is formed, and a vertical wall surface is formed between the upper and lower portions. Therefore, the correction guide 42
The range from the shoulder to the heel of the heat-shrinkable molded product 100 is defined as the correction range.

On the surface of the straightening guide 42, a release layer 42A of, for example, Teflon (trade name) is formed to prevent sticking when retreating from the heat-shrinkable molded product 100 and pull the molded product surface. It is not stubborn.

Further, the interval X between the adjacent surfaces of the straightening guides 42 is made narrower as shown by the symbol X2 (X1> X) than the outer dimension X1 in the arrangement direction of the primary blow molded products 90.
2), the side of the primary blow molded article 90 in the arrangement direction, that is,
The outer dimensions of a surface adjacent to and parallel to the blow parting surface are reduced. The reduced size is set to a value smaller than the lateral size of the blow type cavity.

Further, the driving unit of the correction guide 42 includes:
The piston 60A is constituted by an air cylinder 60 having a piston 60A fixed to the back surface of the sliding member 44, and the movement stroke (S) of the piston 60A is between the primary blow molded products 90 and the outermost side surface in the arrangement direction. The stroke is set so that the body of the correction guide 42 can enter the position facing the position.

Accordingly, the correction guide 42 is provided with the sliding member 44.
Of the heat-shrinkable molded articles 100 arranged on the outer side of the outermost heat-shrinkable molded articles 100, and from the entry position to a position where the movement of the primary molded article is not hindered. It is possible to evacuate.

The air cylinder 60 is generally provided with a heat-shrinkable molded product 100 as shown by a solid line in FIG.
The heat-shrinkable molded product 100 is moved to the opening 240I of the heating furnace 240 by the rotation of the turntable 22 without waiting in a retreat position where the heat-shrinkable molded product 100 does not hinder the movement of the heat-shrinkable molded product 100 without entering between them. Figure 3
As shown by a two-dot chain line in FIG.

For this reason, the operation state of the air cylinder 60 is set by a control unit (not shown), and the control unit controls the air cylinder 60 on the turntable 22 holding the heat-shrinkable molded product 100. The air cylinder 60 is moved from the standby position for a predetermined period of time after a slight time delay from when a signal from a detection unit (not shown) for detecting that the block has opposed the bottle width correcting device 40 is input. The correction guide 42 is moved so as to enter between the heat-shrinkable molded products 100 and between the heat-shrinkable molded products 100 and the side in the arrangement direction. The above-described time delay is set so that the relief mechanism 46 described later changes to a state of eliminating the increase in the internal pressure in the heat-shrinkable molded product 100. A time equal to or shorter than the time at which the station stops is set.

A pair of guide rods 46 are fixed to the sliding member 44 on the side where the piston 60A is fixed, and the guide rods 46 are fixed on a base. The sliding member 44 is supported by a bracket 48, and guides the sliding member 44 in a direction perpendicular to the arrangement direction of the primary molded products 90.

On the base on the side where the bottle width correcting device 40 is provided, a mechanism 4 for relieving the rising pressure of the primary blow molded product 90 when the internal pressure rises.
6 are provided.

That is, as described in, for example, JP-A-3-205124, the relief mechanism 46 is used to supply a pressurized fluid for secondary blow molding to the inside of the primary blow molded product 90. Of the check valves provided in the passage and the passage for eliminating the pressure increase during the heat treatment from the inside of the primary blow molded article 90, the check valve is provided for the former check valve. The stop valve is opened when a pressurized fluid is introduced into the interior of the primary blow molded product 90.

Then, in FIG.
The air cylinder 74 includes an air cylinder 74 provided on a fixed support base 70 installed on a base, and an air release rod 76 fixed to the tip of a piston of the air cylinder 74. The relief mechanism 46 opens the check valve by opening the check valve 76 before the correction guide 42 advances the body portion between the heat-shrinkable molded products 100 and toward the side in the arrangement direction. It is supposed to. Also,
The projecting timing of the air release rod 76 provided in the relief mechanism 46 is set by the control unit. In the case of the present embodiment, the block of the rotary plate 22 is Is determined so as to start projecting at a time point when it is detected that the object has faced. Note that the return timing of the air release rod 76 is desirably set to a point in time when the time during which the check valve can be maintained in the open state has elapsed until the correction guide 42 returns to the standby position. this is,
For example, due to an assembly error such as a deviation in the extension direction of the straightening guide 42, the straightening guide 42 is moved to the heat shrinkable molded product 100.
When the molded article is pressurized both at the time of entering and retreating, the increase in pressure due to the pressurization can be eliminated.

Next, the operation will be described.

In the oven blow stage 20,
The transferred primary molded article 90 is set on the rotating plate 22 with the neck held by the holding member, and the rotating plate 2
The inside of the heating furnace 24 can be moved according to the rotation of 2.

The primary molded article 90 having moved through the heating furnace 24 reaches the heating furnace 240 located on the front side of the blow mold clamping device 30 and faces the bottle width correcting device 40.

The heat-shrinkable molded product 100 is a bottle width straightening device 4
When it is detected by the position detecting means that the user has faced 0,
Air release rod 76 provided in relief mechanism 46
And the check valve for introducing the pressurized fluid provided on the holding member is opened. When the air cylinder 60 is driven, the body of the straightening guide 42 is moved between the heat-shrinkable molded products 100 and toward the side in the arrangement direction. Therefore, in the heat-shrinkable molded product 100, the surfaces facing the adjacent ones and the outermost surface in the arrangement direction are adjusted by the straightening guide 4.
The outer diameter of the secondary blow-molded article 110 is reduced by pressurizing by the pressure of 2, so as to be smaller than the outer diameter of the secondary blow molded product 110, in other words, the lateral dimension of the cavity of the blow mold clamping device 30. Then, the internal pressure of the heat-shrinkable molded product 100 whose outer diameter dimension is reduced by the straightening guide 42 entering is increased at the time of reduction, but the increased pressure is removed to the outside via the check valve on the holding member side. Therefore, it does not hinder the reduced deformation.

On the other hand, when a predetermined time has elapsed, the straightening guide 42 of the bottle width straightening device 40 and the air release rod 7
6 returns to the initial position. At this time, the correction guide 42
The release layer 42A provided on the surface of the primary blow
-It can return without sticking to the surface of the molded article 90, and does not cause the heat shrink molded article 100 to lose its shape. Therefore, the heat-shrinkable molded product 100 is placed in the cavity with the outer dimensions at positions adjacent to and in parallel with the parting surface of the blow mold smaller than the lateral dimensions of the cavity. Next, blow molding is performed.

In the above-described embodiment, as the structure of the bottle width correcting apparatus, a structure using the primary blow molded articles and a straightening guide which advances and retreats toward the side surface in the arrangement direction is shown. The present invention is not limited to the structure of the embodiment, and various modifications can be made within the scope of the present invention. For example, instead of a straightening guide having a tapered surface that can move forward and backward, a swingable clamping structure is used, and the outer dimensions are clamped by clamping the part facing the parting surface of the mold used in the secondary blow molding process. It is also possible to adopt a structure to reduce. Further, a heater or a cooling or temperature control structure may be provided on the straightening guide so that the primary molded product is not excessively cooled or heated.

[0047]

As described above, according to the present invention, the outer diameter of the heat-shrinkable molded product which is subjected to the heat treatment and reaches the secondary blow molding is made smaller than the outer diameter of the secondary blow molded product. At this time, it is possible to prevent a part of the heat-shrinkable molded product from entering the parting surface of the blow mold. Therefore, even when using a heat-shrinkable molded product in which uneven thickness has occurred during primary blow molding, burrs do not occur on the outer periphery of the secondary blow molded product during secondary blow molding, and the final molded product The yield can be improved by suppressing the defect rate.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing a molded product obtained in an oven blow molding machine which is an example of a molding device of the present invention.

FIG. 2 is a plan view for explaining a configuration of an oven blow stage in the heat-resistant container forming apparatus of the present invention.

FIG. 3 is a schematic diagram showing a configuration of a heating furnace and a bottle width correcting device provided in an oven blow stage shown in FIG. 2;

FIG. 4 is a partial plan view of the bottle width correcting device shown in FIG.

FIG. 5 is a perspective view showing a structure of a straightening guide used in the bottle width straightening device shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Forming apparatus 20 Oven blow stage 22 Rotating disk 24 Heating furnace 30 Mold clamping apparatus 40 Bottle width straightening apparatus 42 Straightening guide 46 Relief mechanism 76 Air release rod 100 Heat shrink molded article

──────────────────────────────────────────────────続 き Continued on the front page (72) Saburo Suzuki, Inventor 4586-3, Komoro-shi, Nagano Prefecture Nissei ASB Machine Co., Ltd. (56) References JP-A-63-122516 (JP, A) (58) ) Surveyed field (Int.Cl. ⁷ , DB name) B29C 49/18 B29C 49/42-49/80

Claims (4)

(57) [Claims] 1. A preform is biaxially stretched and blow-molded in a longitudinal direction and a transverse direction to form a primary blow-molded product. After shrinking the primary blow-molded product in a heat treatment furnace, a secondary mold comprising a split mold is formed. In a molding apparatus for forming a heat-resistant container by secondary blow-molding the heat-shrinkable molded product in a cavity of a blow mold, the outer diameter of the heat-shrinkable molded product is made larger than the outer diameter of the secondary blow-molded product. An apparatus for forming a heat-resistant container, comprising a straightening means for reducing the size of the container. 2. The molding apparatus according to claim 1, wherein the straightening means includes a heat-shrinkable molded product inside, and when clamping the split mold, both ends in a direction parallel to a parting surface of the split mold. An apparatus for forming a heat-resistant container, wherein the apparatus is reduced in size for a dimension between the containers. 3. The shaping apparatus according to claim 2, wherein the straightening means is provided so as to be able to advance and retreat with respect to the inside of the heat treatment furnace. A molding apparatus for a heat-resistant container, comprising: a straightening guide member having a size set to reduce the size in the arrangement direction by applying pressure. 4. The manufacturing apparatus according to claim 1, further comprising means for maintaining the internal pressure of the primary blow-molded article at a predetermined pressure during the heat-shrink molding, and this means increases the internal pressure at least when correcting the heat-shrink molded article. An apparatus for forming a heat-resistant container, comprising a relief member for removing a part or all of a part.