JP2003159739A - Compression molding equipment for compressing and molding preform for blow molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compression molding equipment capable of molding a mouth of a shape and dimensions, corresponding to those of a mouth part of a final molding, just as required, with adequate accuracy without the occurrence of fins, etc. <P>SOLUTION: This compression molding equipment comprises: a female mold (32) which has a cavity (43); a driven member (47) which is arranged around the female mold (32), and made slidable over a prescribed range with respect to the female mold (32) in such a manner as to be coaxial with the female mold (32); a male mold (33) which is equipped with a core mold (53) arranged above the female mold (32) so as to be ascendable/descendable with respect to the female mold (32), and a driven mold (57) arranged around the core mold (53) openably/closably and ascendably/descendably over a prescribed range with respect to the core mold (53) in such a manner as to be coaxial with the core mold (53); a spring for urging the driven mold (57) downward; and a spring for urging the driven member (47) upward with a relatively great urging force. <P>COPYRIGHT: (C)2003,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention
Must be blow-molded with mouth of corresponding shape and dimensions
Compression molding of a blow molding preform having a bottom body
And a compression molding apparatus for the same. [0002] Stretch blow molded plastic containers, especially
Polyester containers have become popular today,
Liquid detergent, with appropriate transparency and moderate gas barrier properties
Outside of liquid products such as shampoo, cosmetics, soy sauce, sauce
In addition, carbonated drinks such as beer, cola, cider, fruit juice,
Other beverage containers such as mineral water and desserts
It is widely used for containers, containers for miso and cup products. [0003] When molding polyester containers,
Ester injection molding allows for much larger dimensions than the final container
Preform small and amorphous polyester preforms
The preform is preheated to its stretching temperature.
And stretch in the blow mold in the axial direction.
The method of blow-drawing in the direction is adopted. [0004] The shape of the preform is determined by the shape of the mouth of the container.
Mouth and bottomed body to be stretch blow molded
For a vertically long container, the overall shape was tested.
Tubular ones are common. In the mouth, for example, for sealing
Means for engaging with the open end and the lid are formed. Also this
At the bottom, from the center of the bottom to the outside due to the need for injection molding
A protruding gate portion is always formed. [0005] Preforms can be manufactured by compression molding of resin.
Also known, for example, International Publication WO97 / 32
No. 706 has a cavity for forming a preform.
Prepare a compression mold to mold and mold thermoplastic resin into precursor
Together with the precursor into a compression mold where the precursor is
Is fixed and fixed in the cavity
The precursor is not completely filled in the compression mold,
Before being compressed into a shape, a certain amount of
Have a shape that is supported by the method,
Precursor was heated prior to placing in compression mold
It is described that the precursor is compression molded in a compression mold. [0006] However, the injection molding
The gate formed on the preform is shaped to improve productivity and
Many in terms of manufacturing costs and properties of the final blow molded product
Has become a problem. That is, this gate portion is cut.
Requires a special cutting process, which reduces productivity.
Cause. In addition, the cut gate part is scraped.
And become waste of resources. In addition, this game
The rest of the sheet may cause crystallization and whitening of the final blow molded product.
In addition to causing deterioration of appearance characteristics,
Stretch blow molding due to the flow orientation of
This can lead to uneven orientation and non-uniform texture when forming,
This also causes bottom cracks. In addition, in injection molding, large shear
Since the force acts, molding at high temperature is necessary,
The question is that thermal degradation (thermal degradation) of the resin may occur due to the history.
It is a title. For this reason, the conventional PET (polyethylene
Phthalate) In the manufacture of containers, the inherent
Expecting a decrease in viscosity in advance, high intrinsic properties by solid-state polymerization
The use of PET with viscosity requires increased costs.
Has brought. In addition, the resin injected into the mold
Not only cooling of resin but also flow of resin
The degree of freedom in setting the mold temperature is small, and the injection molding time
However, there is also a productivity problem in that it becomes longer. Forming a preform by the above compression molding method
Says that it is possible to reduce the thermal degradation of resin due to injection molding.
Although it has the advantage, it avoids excess or shortage of resin supply to the compression mold.
The resin is once thermoformed into a precursor, and this precursor is added again.
Heat and supply to injection mold, heated precursor in compression mold
In addition to thermoforming, compression molding must be performed.
Still improved in that reheating for shape is required
There is something to be done. Therefore, the technical problem of the present invention is to reduce the resin
It is supplied to the compression mold without the need to mold into a precursor.
Despite the slight variation in the amount of resin
Burr the shape and size of the mouth corresponding to the mouth of the final molded product.
Molding precisely and as required without causing any problems
To provide a compression molding machine that allows
You. [0010] To achieve the above technical object
According to the present invention, as a compression molding apparatus,
Blow molded with a mouth of the shape and size corresponding to the mouth
Compresses preforms for blow molding with bottomed body to be
It has a cavity as a compression molding device for molding
A female mold, which is disposed around the female mold and is coaxial with the female mold.
A driven member slidable over a predetermined range with respect to the female mold
Disposed above the female mold so as to be movable up and down with respect to the female mold.
Core mold and the core mold disposed around the core mold.
Ascending and descending over a predetermined range with respect to the core mold coaxially with the mold
Male with driven mold movably and openably arranged
A mold, a spring for urging the driven mold downward,
A spring for urging the moving member upward,
Tee forms the outer peripheral surface of the bottomed body of the preform, and
A mold is a portion forming the top surface of the mouth of the preform,
The part that forms the inner peripheral surface and the part that forms the inner surface of the bottomed trunk
The driven mold forms the outer peripheral surface of the mouth of the preform.
Biasing the spring to bias the driven member upward
The force is the urging force of the spring that urges the driven mold downward.
Larger than the male mold with respect to the female mold during compression molding.
When lowered, the driven member comes into contact with the driven mold.
To raise the driven mold relative to the core mold.
Then, while lowering the driven member, the core metal
The mold and the driven mold are integrally lowered.
A compression molding device is provided. In the compression molding apparatus of the present invention, the bottomed cylinder
Before the compression molding of the part is completed, the compression molding of the mouth is completed,
Therefore, the required shape without burr on the mouth
And dimensions. Young resin supply
Dryness variations are compensated for by slight variations in bottom thickness
You. On the other hand, before the compression molding of the mouth is completed,
If you want to complete the compression molding of the body,
The shape and dimensions of the mouth fluctuate due to fluctuations in the amount of resin supplied
And there is a tendency for burr to occur at the mouth. The present invention will now be described with reference to the accompanying drawings.
The preferred embodiments will now be described in more detail. [Overall Configuration of Apparatus] Compression molding apparatus of the present invention
1 (plan view) and FIG. 2 showing the overall arrangement of the device including
In (side view), this device is roughly
Extrusion device 1 for plastic resin, cutting and feeding device 2 for molten mass
And a compression molding device 3 for preform molding. The extruder 1 is used for melting and kneading the resin.
An extruder body 11 is provided, and on the inlet side of this body,
Dry thermoplastic resin powder or pellets to be molded
Vacuum hopper 1 for holding the feed to the extruder body
2 is provided, and on the outlet side of the main body, the decomposition gas in the resin, etc.
Suction vent 13 for sucking out and removing
A die head 14 for receiving the molten resin is provided. Da
Ihead 14 is connected to an extruder nozzle 16 via a pipe 15
Although connected, the die head 14 and the extruder nozzle 16
In between, a gear pump 17 for supplying a fixed amount of molten resin
Should be provided. It should be noted that in FIG.
In order to avoid this, the gear pump 17 is omitted. The apparatus 2 for cutting and supplying a molten mass is shown in FIG.
Front view) and FIG. 4 (side view).
Gripping the molten mass with the cutter 22 provided on the
Of outer gripping member 23 and inner gripping member 24 for
It consists of The cutter 22 is a turret 21
Of the turret 21
Resin extruded from extruder nozzle 16 with rotation
So that the melt 18 can be cut in a direction perpendicular to the extrusion direction
Has become. The outer gripping member 23 is provided in the turret radial direction.
And a circumferentially extending outer portion.
Are fixed to the pocket 21. On the other hand, the inner gripping member 2
4 is the radial direction of the turret with respect to the outer gripping member 23
It is provided movably. The rotary turret 21 of the cutting and feeding device 2
Below the extruder nozzle 16 of the extruder 1 and compression molding
It is provided so as to pass above the female mold 32 of the device 3,
By gripping members 23 and 24 below extruder nozzle 16
The holding of the melt 18 and the cutting by the cutter 22 are performed,
The molten mass 19 in the gripping state by the gripping members 23 and 24
Of the female mold upward and release of the gripping members 23 and 24.
Of the molten mass 19 into the female mold 32 is performed. FIGS. 2 and 4 show that the embodiment shown in FIG.
The thermoplastic resin melt 18 is divided into the male mold 33 and the female mold 3.
2 and extruded in parallel with the axial direction, and cut the molten mass 19
Supplied into female mold 32 while maintaining its parallel state substantially
That the melt 18 is substantially
The resin is supplied in a fixed state, and the molten resin mass 19 is formed into a cylindrical or cylindrical shape.
And the molten mass 19 is supplied
At the position above the center of gravity,
Move from the cutting position C to the mold position M, and
It is evident that this is supplied to The compression molding device 3 is, roughly speaking, a rotary
The turret 31 and the turret 31
Consisting of a large number of female molds 32 and male molds 33
ing. The rotating turret 31 has the melting point already pointed out.
A melt cutting and feeding mechanism 2 is provided, and
The take-out mechanism 34 for the shaped blow molding preform is also provided.
It is attached. The rotating turret 31 is perpendicular to the machine base 35.
Horizontally and rotatably supported by a straight shaft 36
Driven by the motor 37 and the drive transmission mechanism 38
It is designed to be rotated. Female 32 and Male 33
The combination (set) is on the outer circumference of the rotating turret 31
A large number are fixedly provided on the surface. That is, the female mold 32 is
9 while the male mold 33 has a vertical support
The lifting of the hydraulic mechanism and the like via the material 40 and the horizontal support member 41
By the lowering drive mechanism 42, it can move up and down coaxially with the female mold 32.
Noh is provided. The detailed structure of the female mold 32 and the male mold 33,
In FIGS. 5 and 6 showing the forming process step by step, the female mold 32 is shown.
Has a cavity 43 and a bottom
Vent 44 and bottom and taper to eliminate trapped air
A vent portion 45 is also provided at a connection portion with the connection portion. Ma
In addition, small upward protrusions are formed around the upper portion of the cavity 43.
A portion 46 is formed. Its operation will be described later.
You. Furthermore, it can slide around the female mold 32 coaxially with the female mold.
The driven member 47 having a ring shape is provided.
7 has a downwardly extending shaft 48, the lower end of which has a strike.
A stopper 49 is formed, and the stopper 49 is
It is housed in the lower recess 50 of the female mold 32. Hide
The stopper 49 is located between the upper surface and the lower surface of the lower concave portion 50.
It will be understood that it is possible to move up and down. Also, stopper
-49 is applied upward by means such as a spring (not shown).
It is being rushed. Furthermore, on the upper inner peripheral surface of the driven member 47,
An engagement taper portion 51 having an upwardly increasing diameter is formed.
Have been. On the other hand, the male mold 33 is a supporting member which can move up and down.
A core mold 53 fixed to 52 is provided. This core
The mold 53 is a part for forming the mouth top surface of the preform.
A portion 54, a portion 55 for forming an inner peripheral surface of the mouth,
A portion 56 for forming the inner surface of the bottom tapered body;
Have. Around the core mold 33, the core mold 33 is coaxial and coaxial.
There is a driven mold 57 that can be opened and closed.
The driven mold 57 is fixed to a driven support member 58 and
Although not shown, the support member 52 and the driven support member 5
A push spring is provided between 8 and the driven mold
Is urged downward. On the lower inner peripheral surface of the driven mold 57
Is provided with a portion 59 that forms the outer peripheral surface of the mouth of the preform.
On the other hand, the lower outer peripheral surface is engaged with the diameter decreasing downward.
Taper portion 60 is formed. In the compression molding apparatus shown in FIGS.
The pressing force (absolute value) of each member performs each operation smoothly.
Therefore, it is set as follows. Pressing force of male mold 33> Pressing force of driven member 47> Driving die 5
Pressing force of 7 The molding operation by the above device is performed as follows.
You. (A) Melt extrusion process: For molding thermoplastic polyester, etc.
The resin is supplied to the vacuum hopper 12 of the extruder 1 and
In the state where moisture absorption from outside air is shut off, the extruder body 1
When it is separated in 1, it is melted and kneaded by a screw and die
Via the head 14 and the pipe 15 and by the gear pump 17
The fixed amount is supplied to the nozzle 16 and is pushed into a cylindrical shape from the nozzle 16.
It is started. (B) Cutting and supply step: from nozzle 16
The melt-extruded resin stream 18 is cylindrically or
Or into a molten mass 19 shaped like a cylinder,
The molten mass 19 is gripped by the gripping members 23 and 24 and cut.
From the cutting position C to the supply position M to the female mold 32, a substantial temperature
Transfer with rotation of the turret without lowering
It is moved into the female mold 32. (C) Compression molding step: The application shown in FIG.
In the roach process, the cavity mold 43 and the core mold 53
Is still open, and the molten mass 19 is
It is stored upright. The core mold 53 starts to descend
I have. In the cavity mold clamping process shown in II of FIG.
The core mold 53 descends into the cavity, and the molten resin
19 'is substantially defined by the cavity 43 and the core 53
Filled with space. At the same time as the start of compression molding,
The residual air in the chamber is quickly ventilated through vents 44 and 45.
Released to the outside of the crab. At the same time, the driven mold 57 descends
And abuts on the driven member 47, but on the driven support member 58.
There is still a gap between the surface and the lower surface of the male support member 52.
You. In the core mold clamping process shown in III of FIG.
As a result, the core mold 53 further descends, and
The surface contacts the lower surface of the male support member 52. With this
The molten resin 19 ′ in the cavity follows the core mold 53.
It flows into the space defined by the moving die 57. In the solidification process at a high temperature shown in IV of FIG.
As a result, the core mold 53 is further lowered slightly, and
The member 47 is also lowered, and the cavity 43, the core mold 53 and
And the space defined by the driven mold 57 must be filled with resin.
And In the solidification process at a low temperature shown in FIG.
As the resin temperature drops, the resin shrinks in volume,
However, distortion due to this volume shrinkage is
Absorption by applying compressive force to the mold (core 53)
be able to. In this case, the core mold 53 and the cavity 4
Of course, it is necessary to move so that 3
The upwardly directed small protrusion 46 of the cavity 43 is
57 to absorb volume shrinkage,
A pure blow molding preform can be obtained. Step of taking out the compression molded preform
Are indicated by steps I to V in FIG. Step I
This shows a stage at which molding has been completed. Core in Step II
The mold 53 starts rising, and the mold opening is started. Step
In Step III, the core mold 53 is moved up before the driven mold 57.
Ascending, core removal from the formed preform 60 is performed.
Be done. In step IV, the core mold 53 is further raised,
The preform 60 is taken out of the cavity 43.
You. In step V, the driven mold is
The mold 57 moves to a position outside the diameter (the position indicated by the dotted line) and
The blow molding preform 60 held is released. [Resin raw material] In the present invention, blow molding
The raw material resin for forming the preform for
Use any formable thermoplastic resin
Can be. As such a resin, polyethylene tereph
Tallate (PET), polybutylene terephthalate (P
BT), heat of polyethylene naphthalate (PEN), etc.
Plastic polyester, mainly composed of these ester units
Copolyester or blends thereof; Polycarbonate
-Carbonates; acryl-butadiene-styrene copolymer
Body (ABS resin); polyacetal resin; nylon 6,
Nylon such as nylon 66 and their copolymerized nylon
Acrylic resins such as polymethyl methacrylate; Eyes
Sotactic polypropylene; polystyrene, etc.,
Low-, medium- or high-density polyethylene, ethylene-
Propylene copolymer, ethylene-butene-1 copolymer,
Styrene-butadiene thermoplastic elastomer etc.
be able to. These plastics have a product quality
Various additives within a range not impairing, for example, coloring agents, purple
It can be blended with external absorbent, release agent, lubricant, nucleating agent, etc.
Wear. Particularly, polyester is used as the thermoplastic resin.
It is preferred to use
Intrinsic viscosity (η) is 0.5 dl / g or more, especially 1.3 to
Those in the range of 0.7 dl / g are preferred. Also,
Polyesters include diethylene glycol units.
With an amount of 1.60% by weight or less, especially 1.50% by weight or less
Those within the range are preferably used. [Molding conditions] Melt extrusion temperature of thermoplastic resin
(Die head temperature) varies depending on the resin,
Generally, Tm is determined based on the melting point (Tm) of a thermoplastic resin.
+ 100 ° C to Tm + 10 ° C, especially Tm + 40 ° C to T
It is preferably in the range of m + 20 ° C. Than the above range
At low temperatures, the shear rate becomes too high and uniform melting
Extrudates can be difficult to form, while
At temperatures higher than the above range, the degree of thermal degradation of the resin increases.
Or draw down for polyester
Tends to be too large. The weight of the molten mass to be cut, that is, the basis weight is naturally
Determined by the final blow molded product, generally 10
From 0 to 2 g, especially 40 to 10 g
An appropriate value should be selected depending on the strength. Further, the molten mass has a columnar shape or a shape close thereto.
Is advantageous in terms of handling, but the diameter of the molten mass
The ratio (H / D) between (D) and height (H) is generally 0.8
The range of 4 to 4 prevents the temperature of the molten mass from lowering as much as possible.
It is advantageous in that it can be stopped and the molten mass can be easily poured into the female mold.
is there. That is, when H / D is out of the above range, the surface area of the molten mass is
The temperature tends to increase and the temperature tends to decrease. An arbitrary cutter is used to cut the molten resin mass.
It is used, but those that can prevent resin adhesion are preferable.
Suitable. For example, surface treatment such as shot blasting
It is effective for A gripping member for moving the molten resin block;
Then, use something made of a material with good thermal conductivity,
Those with the smallest possible contact area with the resin are preferably used.
It is. From cutting the molten resin mass to putting it in the mold,
It is better to do it within the time already pointed out. As the compression mold, the bottom or its vicinity
Used with fine gaps or porous parts
The fine gap is located at or near the bottom of the female mold.
Split into pieces and eliminate air between these pieces
To form minute gaps or exhaust air to the mold.
By forming holes for removal.
Can be. Further, the porous portion is made of, for example, a sintered metal or the like.
It can be used by processing products. The surface temperature of the compression mold is determined by the solidification of the molten resin.
Temperature, such as polyester
In this case, a temperature range of 65 to 30 ° C. is appropriate. Mold table
In order to maintain the surface temperature within the above range, cool water in the mold
Alternatively, a medium such as temperature-controlled water may be passed through. The molding force required for compression molding is quite small.
One of the features is good. The specific molding force is
It depends on the type and size of the preform for blow molding.
Generally, 800 to 50 kg
f, especially a molding force of 600 to 150 kgf is appropriate.
You. According to the present invention, by one-stage compression molding,
No need for gates or other trimming operations
-Since a preform for molding is obtained,
Can be used as it is in the stretch blow molding process,
It has many advantages in terms of process simplicity and productivity. [Preformed product for blow molding] In the present invention
In FIG. 7, which shows a preform for blow molding,
The molding 60 is roughly divided into a mouth 61 and a tapered bottomed cylinder.
And a part 62. The mouth 61 is a final molded product
It is the mouth of the bottle.
Lid locking part 63 and support ring 6 necessary for sealing with lid
4 are formed. The bottomed body 62 is stretch blow molded.
The tapered side wall 65 and the
Consisting of a smoothly connected downwardly convex bottom 66
I have. As already pointed out, the bottom 66 has the rest of the gate
There are no wrinkles. The mouth 61 and the bottomed body
62 is smoothly connected via a connecting portion 67. The tapered side wall 65 and bottom 66
Means compression moldability and moldability at the time of final stretch blow
In terms of size, there is a certain preferred range for its size and shape.
You. Generally, the outer surface of the side wall portion 65 is a frustoconical surface,
66 is a partial sphere smoothly connected to the truncated cone surface
Surface is preferred in terms of moldability, but blow molded products
It may be any shape according to the shape. one
On the other hand, the inner surface of the side wall portion 65 also increases in thickness from the inner periphery of the connection portion.
It is a frustoconical surface connected via an inclined portion 66. Side wall
The taper angle (θ) of the outer surface is 0.5 to 89.5 °
Such a material is preferable from the viewpoint of moldability. Figure 9
In the case of a blow molding of the present invention in the case of a taper angle of 0.8 °,
FIG. 10 shows a cross section of the preform, and FIG.
Shows the cross section of the blow molding preform of the present invention in the case
I have. The thickness of the side wall portion 65 and the bottom portion 66 is the inclination described above.
The thickness may be uniform except for the portion 67, and
There may be changes, e.g. the side wall thickness towards the bottom
May be distributed. The above preform is stretch blow molded as it is.
It can be used for shapes,
To give heat and rigidity, heat the mouth at the stage of preforming.
It may be crystallized and whitened by the treatment, and
Preforms are molded into bottles by biaxial stretch blow molding
After that, the mouth of the obtained plastic bottle is crystallized,
It may be whitened. [Stretch Blow Molding] The above preform is stretched.
Heat to temperature and stretch this preform in the axial direction
Then, it is blow-stretched in the circumferential direction to produce a bottle. Prior to stretch blow molding, a preform
Using hot air, infrared heater, high frequency induction heating, etc.
Preheat to a suitable stretching temperature. The temperature range is poly
85-120 ° C., especially 95-11 in the case of esters
It should be in the range of 0 ° C. The preform is placed in a known stretch block.
It is fed into a low molding machine, set in a mold, and
In addition to stretching in the axial direction by pushing,
It is blow-stretched in the circumferential direction by penetration. The stretching ratio in the final bottle is the area ratio.
1.5 to 25 times is appropriate.
The stretching ratio is 1.2 to 6 times, and the circumferential stretching ratio is 1.
It is good to make it 2 to 4.5 times. The blow-molded preform of the present invention
8 (side view) showing an example of a bottle manufactured from the above.
The bottle 70 has a mouth 61, a frustum-shaped shoulder 71,
An upper body 72, a lower body 73, and a bottom 74 are provided. Mouth 6
The structure and dimensions of 1 are exactly the same as those of the preform.
You. The bottom part 74 is provided between the ground part 75 and the ground part.
The raised bottom 76 is formed. Bottle
A panel (mirror) for absorbing reduced pressure deformation
(Part) 77 is formed via a rib 78. Also below
The connecting portion between the torso 73 and the shoulder 71 and the upper torso 72 is supplementary.
A strong circumferential concave bead 79 is formed. The preform for blow molding in the present invention
The bottles manufactured from them have the shape and structure
And excellent physical properties such as strength and impact resistance
It has the advantage of being significantly better. [Embodiment 1] The present invention will be described with reference to the following examples.
You. Polyethylene terephthalate manufactured by Kanebo Gosen Co., Ltd.
Resin EFS-7H is dried with a dryer, 65mm diameter
・ Using an extruder with an L / D of 27, a diameter of 22 mm
For cutters that extrude vertically from the nozzle and rotate horizontally
Therefore, the resin in the molten state is cut horizontally and melted with a weight of 20 g.
Creates a molten mass, transports it immediately, and synchronizes with cutter rotation
And drop it vertically onto the rotating female mold in the molding machine.
While closing the mold at high speed, do not exhaust residual air in the mold at the same time.
It is compressed and molded while applying a force of about 700 kgf.
After making the mold, open the mold, caliber 38mm, height 63m
m, average thickness 3mm, weight 20g
Shape was obtained. Wrinkles at and near the bottom of the preform
It is recognized after the residual air discharge part without any whitening
However, the surface was extremely smooth with no remaining gate. Forecast
When observing the bottom of the molding with polarized light,
It was extremely scarce. Test this preform
After heating to 110 ° C with a stretch blow molding machine for
-High pressure air of 35 atm after stretching in the mold in the longitudinal direction
Blow molding, height 140mm, trunk diameter 67.5m
m, a bottle having a content of 380 cc was obtained. The appearance of the bottle
It was beautiful without wrinkles or streaks. 3 bottles of water
Add 50cc, seal with cap, 1.2m height
Even when it is dropped 15 times
Did not crack. [Comparative Example 1] No residual air in the mold was discharged
Under the same conditions as in the example except that compression molding was performed
A preform for low forming was obtained. The bottom of the preform and
In the vicinity, wrinkles and whitening due to slight crystallization were observed.
Was done. This preform is converted to a stretch blow molding machine for testing.
And then stretched in the blow mold in the machine direction
After that, blow molding with high pressure air of 35 atm.
140mm in diameter, 67.5mm in body diameter, 380cc in content
Got a bottle. The appearance of the bottle is wrinkles and streaks around the bottom
There was no commercial value. 35 bottles of water
0cc, sealed with a cap and from 1.2m height
After dropping it 7 times, the bottom of the bottle
There was a crack from the periphery. [Comparative Example 2] The cut molten mass was once
After receiving the rough mold, it is transferred into the mold and then compression molded.
Under the same conditions as in the example except that
A molded product was obtained. A pole is located at and near the bottom of the preform.
The wrinkles were noticed. Use this preform for testing
After heating to 110 ° C with a stretch blow molding machine
After stretching in the mold in the longitudinal direction, press
Blow molding, height 140mm, body diameter 67.5m
m, a bottle having a content of 380 cc was obtained. The appearance of the bottle
There are large wrinkles and streaks from around the bottom to the trunk
It had no commercial value. 350 cc of water in the bottle
Put in, seal with cap and drop from 1.2m height
Around the bottom of the bottle after three repetitions
Cracking occurred. According to the present invention, a resin is once formed into a precursor.
The amount of resin supplied to the compression mold without the need to shape
Despite slight fluctuations in the final compact,
Burrs etc. are generated on the mouth of the shape and size corresponding to the mouth.
For blow molding that is exactly as required without turning
A preform can be formed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view showing an arrangement of an entire apparatus including a compression molding apparatus constituted according to the present invention. FIG. 2 is a side view of the apparatus of FIG. FIG. 3 is a plan view of an apparatus for cutting and supplying a molten mass. FIG. 4 is a side view showing each stage of the apparatus of FIG. 3; FIG. 5 is a side sectional view for explaining each stage of the compression molding process. FIG. 6 is a sectional side view for explaining each stage of a step of taking out a preform after compression molding. FIG. 7 is a sectional view showing an example of a preform for blow molding. FIG. 8 is a side view showing an example of a bottle manufactured from the preform of FIG. 7; FIG. 9 is a sectional view showing another example of a preform for blow molding. FIG. 10 is a sectional view showing still another example of a preform for blow molding. [Explanation of Symbols] 3: Compression molding device 32: female mold 33: male mold 43: cavity 47: driven member 53: core mold 57: driven mold

Continuation of front page    (72) Inventor Kiyoshi Kawaguchi             3359-9 Shinyoshida-cho, Kohoku-ku, Yokohama-shi, Kanagawa F term (reference) 4F201 AA24 AG07 AH55 BA03 BC02                       BC12 BC15 BD05 BD06 BM06                       BM07 BM12                 4F208 AA24 AG07 AG23 AH55 AM33                       LA02 LA04 LG16 LG32 LG35

Claims (1)

Claims: 1. A compression molding method for a blow molding preform having a mouth having a shape and dimensions corresponding to a mouth of a final molded body and a bottomed body to be blow molded. A compression molding apparatus, a female mold having a cavity, a driven member disposed around the female mold and slidable over a predetermined range with respect to the female mold coaxially with the female mold, A core mold disposed above the female mold so as to be able to move up and down with respect to the female mold; A male mold having a driven mold disposed so as to be vertically movable and openable and closable over a range, a spring for urging the driven mold downward, and a spring for urging the driven member upward. Wherein the cavity forms an outer peripheral surface of a bottomed body of the preform, and the core mold is formed of the preform. A portion that forms the top surface, a portion that forms the inner peripheral surface of the mouth, and a portion that forms the inner surface of the bottomed body, wherein the driven mold forms the outer peripheral surface of the mouth of the preform; The urging force of the spring for urging the driven member upward is larger than the urging force of the spring for urging the driven mold downward, so that the male mold is lowered with respect to the female mold during compression molding. When the driven member abuts on the driven mold, the driven mold is relatively raised with respect to the core mold, and then the driven mold is lowered while the driven mold is lowered. A compression molding apparatus, wherein the mold is lowered integrally.