JPS58124611A - Preparation of hollow plastic body - Google Patents

Abstract

PURPOSE:To prevent a hollow molded product from breaking in the vicinity of the boundary of its middle wall portion and its flange portion by such an arrangement that a piece of plastic raw material is introduced into a dice cavity with its central portion compressed by an upper plunger and a lower plunger. CONSTITUTION:A bottom surface 1a and side surface 1b of an upper plunger 1 are heated and maintained, by a built-in heater, in the vicinity of a temperature at which molecular orientation of plastic takes place, and the central portion 10a of a piece of a plastic raw material 10 is pressure held between the bottom surface 1a of the upper plunger 1 and the upper surface 2a of a lower plunger 2 and it is introduced into a lower cavity 3b. After a hollow molded product 5' is formed, pressurized fluid is sent into the interior of the hollow molded product 5' through an introducing hole 7, while the plunger 1 is made to return, and its middle wall portion 5b is inflated and then it is cooled off and hardened by bringing it in contact with the internal surface of the dice cavity 3b which is maintained at a temperature lower than the lower limit of the temperature at which molecular orientation takes place.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a hollow plastic body, and more particularly to a method for producing a can-shaped plastic hollow body having a thin body wall with molecular orientation and a large height/diameter ratio. Relating to a method particularly suitable for.

Japanese Patent Publication No. 43-8631' discloses a method for manufacturing a can-shaped plastic hollow body whose body wall is molecularly oriented and has improved transparency, strength, and gas barrier properties. A method is disclosed in which a preform is formed, the peripheral portion of the preform is tightened, and the central portion is extruded into a mold cavity while being compressed while maintaining the molecular orientation temperature to form a body wall. However, this method requires a step of forming a preform, making it difficult to prepare a preform such as a laminate, and before extruding the preform into the mold cavity. There is a problem in that it requires time and effort to uniformly heat the molding temperature to the molding temperature. Furthermore, Japanese Patent Application Laid-Open No. 54-131663 discloses a method for manufacturing a two-layer can-shaped plastic container, but this is a melt-molding method, and the container has transparency due to molecular orientation. It is not a method for producing plastic containers with improved properties.

The present invention has been made in view of the problems of the prior art described above. In a method for manufacturing a hollow body, a peripheral edge portion corresponding to the flange portion of a flat piece of molecularly oriented plastic material having a substantially uniform thickness and having a temperature below the upper limit of the temperature at which molecular orientation is possible is held; A central portion that substantially corresponds to the wall portion is introduced into the die cavity while being compressed by a first sylanger and a second plunger, and extends from between the first silanger and the second plunger. A hollow molded body is formed by forming the body wall portion of the plastic material piece so as to be in contact with the side surface of the first sylanger maintained at a temperature that allows molecular orientation, and then While returning the first syringer, pressurized fluid is sent into the hollow molded body to inflate the body wall, and the die cavity is maintained at a temperature lower than the lower limit of the molecular orientation temperature. The present invention provides a method for producing a hollow plastic body, characterized in that the hollow plastic body is cooled and hardened by contacting the inner surface of the hollow plastic body.

Further, the present invention provides a method for manufacturing a hollow plastic body having a flange portion, a body wall portion and a bottom wall portion, at least the body wall portion having molecular orientation, which includes a flat plastic body having a substantially uniform thickness; The peripheral edge portion corresponding to the flantz portion of a piece of molecularly oriented plastic material whose temperature is below the upper limit of the temperature that allows molecular orientation is held, and the central portion approximately corresponding to the bottom wall portion is placed into a first lunge and a second sylanger. The first plunger and the second plunger are introduced into the die cavity while being compressed.
The material of the plastic material piece extending from between the grungers is hollow, and the body wall portion is formed so as to be in contact with the side surface of the first plunger, which is maintained at a temperature that allows molecular orientation of +4 molecules. A molded body is formed, and then, while returning the first plunger, a pressurized fluid is sent into the interior of the hollow molded body to inflate the body wall, and the temperature is lower than the lower limit of the molecular orientation temperature. The peripheral portion is cooled and hardened in contact with the inner surface of the die cavity held in the die cavity, and the peripheral portion is cooled and hardened before or during introduction of the central portion into the die cavity, or after forming the hollow molded body. The present invention provides a method for manufacturing a hollow plastic body, characterized in that a thin-walled or shaped flange portion is formed by compressing the material so that the material primarily flows outward in the radial direction.

Next, the present invention provides a method for manufacturing a hollow glass body having a flange portion, a body wall portion, and a bottom wall portion, in which at least the body wall portion has molecular orientation. The peripheral edge portion corresponding to the flange portion of the molecularly oriented glass material piece whose temperature is below the upper limit of molecular orientation temperature is sandwiched, and the center portion approximately corresponding to the bottom wall portion is placed between the first glascier and the 20th glansha. The plasti is introduced into the die cavity while being compressed by a roller/jar, and extends from between the first granular and the second granular.

A hollow molded body is formed by using the material of the raw material so that the body wall portion is in contact with the side surface of the first gland which is maintained at a temperature that allows molecular orientation, and then the peripheral edge portion is formed. is compressed so that the material flows toward the body wall, and at the same time, the first lunge and the second lunge are further introduced into the die cavity, and the flowing material causes the body wall of the hollow molded body to be compressed. After that, while returning the first gransha, a pressurized fluid is sent into the hollow molded body to inflate the body wall, and the temperature is lower than the lower limit of the molecular orientation temperature. The present invention provides a method for manufacturing a plastic hollow body, characterized in that the hollow plastic body is cooled and hardened by contacting the inner surface of the die cavity maintained at a temperature.

The present invention also provides a method for manufacturing a hollow plastic body having a flange portion, a body wall portion, and a bottom wall portion, at least the body wall portion having molecular orientation. A peripheral edge portion corresponding to the flange portion of a piece of molecularly oriented plastic material whose temperature is below the upper limit of molecular orientation temperature is sandwiched, and a central portion approximately corresponding to the bottom wall portion is connected to a first plunger and a second grunger. The material of the piece of plastic material extending from between the first sylanger and the second syringer is introduced into the die cavity while being compressed, and the material of the plastic material piece is heated to a temperature that allows almost molecular orientation of the body wall part. A hollow molded body is formed by forming the hollow molded body in contact with the side surface of the grunge held in the body, and during the introduction, the peripheral edge is compressed so that the material flows toward the body wall. Then, the upper part of the body wall of the hollow molded body is formed using the flowing material, and then, while returning the first syringer, pressurized fluid is sent into the inside of the hollow molded body to form the body wall part of the hollow molded body. The present invention provides a method for producing a hollow plastic body, characterized in that the hollow plastic body is inflated, brought into contact with the inner surface of the die cavity maintained at a temperature lower than the lower limit of the molecular orientation temperature, and then cooled and hardened.

The present invention will be described below with reference to the drawings.

In Figures 1 to 7, 1 is an upper plansha, 2 is a lower grunger, 3 is a die, and 4 is a presser foot.

It is de. The die 3 is fixed to a holding member (not shown), and as shown in FIG.
a and a lower cavity 3b are formed. The upper cavity 3a has a short cylindrical shape, and its inner diameter is set approximately equal to the outer diameter of the flange portion 5a of the plastic hollow body 5 (see FIG. 6) to be formed, while the lower cavity 3b is cylindrical, and its inner diameter is set equal to the outer diameter of the body wall portion 5b of the plastic hollow body 5 to be formed. The inner surface 3al of the upper cavity 3a connects to the inner surface 3b of the lower cavity 3b via a horizontal step 3c.
It is connected to l.

The outer diameter of the upper syringe 1 is equal to the inner surface 3b of the lower cavity.
The clearance X (see Fig. 5) with respect to the hollow molded body 5' to be press-stretched is set to be larger than the wall thickness y of the body wall portion 5'b of the hollow molded body 5' to be press-stretched, for example, z-y= Q, 2-0.
It is set at about 8 dew. A guide hole 7 is formed in the upper granger 1 in the axial direction and is normally closed (FIG. 5). The conduit 7 is communicated with a pressurized air source (not shown) through a conduit and a solenoid valve (not shown), and a limit switch (not shown) causes the bottom surface 1a of the upper syringe 1 to be approximately at the level of the stepped portion 3c of the die 3. When the electromagnetic pulp is located below, the electromagnetic pulp opens and the guide hole 7 is opened.
It is configured such that pressurized air is supplied to. In addition,
The upper plunger l is made of metal (for example, tool steel, etc.),
Preferably, a smooth hard surface treatment layer (for example, a hard chrome plating layer) is formed on the surface. A heater (not shown) is built in, and the bottom surface 1a and the side surface 1b (FIG. 5) of a portion having a height approximately equal to at least the height of the body wall portion 5b of the plastic can body to be formed are as follows: The temperature is maintained near the temperature at which the molecules of the plastic can be oriented.

The lower sylanger 2 is configured to be slidable within the lower cavity 3b, and preferably has a smooth hard surface treatment layer formed on its upper surface 2a.

This is to facilitate the compression and expansion of the material, which will be described later.

The presser foot 4 has a hollow part 4a, and the hollow part 4
The upper plunger 1 is configured to be slidable along the inner surface of a. The bottom surface 4b of the presser foot pad 4 is flat and is disposed to face the stepped portion 3c, and the lower portion 4c of the presser foot pad 4 is movable up and down within the upper cavity 3a, and its outer diameter is The inner diameter of the upper cavity 3a is approximately equal to, but slightly smaller than, the inner diameter of the upper cavity 3a. Presser foot.

The vertical movement of the door 4 is performed via a rod 11 by a drive mechanism (for example, a hydraulic system), not shown.

The upper cylinder/jar 1 and the lower plunger 2 are also moved up and down by a drive mechanism (for example, a hydraulic device) not shown, and the central portion of the plastic piece 10 is moved between the bottom surface 1a of the upper plunger l and the upper surface 2a of the lower plunger 2. In order to be able to apply a controlled compressive force to the central portion 10a when pressing the portion 10a and introducing the portion 10a into the lower cavity 3b, a control mechanism (not shown) is used to control the upper plunger l and the lower plunger 2. The descending speed difference between the two is controlled.

The glass material piece 10 is mainly made of thermoplastic plastic having molecular orientation. Examples of this type of plastic include crystalline polyolefin resins such as isotactic polypropylene, high-density polyethylene, medium-density polyethylene, and low-density polyethylene, linear polyester resins such as polyethylene terephthalate, polycardenate resin, and tetrachloride. vinyl resin, nitrile resin,
Alternatively, these coelectric materials or 5 may be a blend. If transparency is not particularly required for the plastic hollow product, a filler such as talc, calcium carbonate or mica flakes may be mixed therein. The plastic material piece lO is a sheet consisting of these molecularly oriented thermoplastics alone, or a sheet consisting mainly of these molecularly oriented thermoplastics,
A laminate or blend sheet made by laminating or blending an oxygen gas barrier resin such as ethylene-hinyl alcohol copolymer, polyamide, cellulose resin, polyacrylonitrile, -9 vinylidene chloride, or polyvinyl alcohol is added to this. It is formed by cutting to a predetermined size. The thickness of the piece of plastic material 10 is preferably substantially uniform and is preferably about 0.5 to 6 mm, more preferably about 2 to 4 meters. Approximately 0.5
This is because if the plastic hollow body is too thin, it is likely to break during molding, especially at the bottom, while if it is thicker than about 6 inches, breakage is likely to occur near the flange.

In the case of a laminate, generally an integral sheet heat-bonded through an adhesive layer is used, but in the case of the present invention, it is not necessarily necessary to use an integral sheet.
As shown in FIG.
polypropylene sheet pieces), adhesive film pieces 100
b (for example, a piece of maleic anhydride-modified polypropylene film with a thickness of 50 to 150 μm), a piece of barrier thermoplastic glass film 100c (for example, a piece of maleic anhydride-modified polypropylene film with a thickness of 200 to 4 μm)
00 μm ethylene-vinyl alcohol copolymer film piece), an adhesive film piece 100b, and a molecularly oriented thermoplastic plastic sheet piece 100a (in the figure, large voids are shown between each layer for clarity of explanation). However, in reality, there are almost no voids) may be used as the plastic material piece 10. It is presumed that this is due to the sagging phenomenon that occurs between each layer when the material at a temperature that allows molecular orientation is compressed between the upper silane 1 and the lower silane 2 and is extended along the side surface 1b of the upper silane 2. This is because, during molding, sufficient bonding is achieved between the layers except for the 7-run section 5&. This is because the above-mentioned joining is also performed for the 72-inch portion 5a when it is compressed by the method shown in FIGS. 10 and 11, which will be described later.

In this case, 0) it is possible to reuse the cutting (punching) waste, and (b) the production of a thick laminate (the thickness of the plastic material piece 10 is uniform, preferably about 2 to 6 mm) (for example (by simultaneous melt extrusion) has many technical problems, such as difficulty in winding, a slow cooling rate, which slows down the production rate, and a drop in formability due to an increase in the size of microcrystals. This problem can be solved, and (c) when a plastic hollow body is molded using the preheated plastic material piece 10, the preheating time can be shortened.

In addition, as shown in FIG. 9(b), an adhesive film piece 10 is attached to the molecularly oriented thermoplastic plastic sheet piece 100a.
A plastic material piece 10 simply sandwiched between two laminate pieces 101 to which a barrier thermoplastic plastic piece 100C is bonded, or a plastic material piece 10 as shown in FIG.
) As shown in ), prepare a plurality of relatively thin sheets (three in the figure).
It is also possible to use a plastic material piece 10 obtained by manufacturing laminated material pieces 102 and simply stacking these pieces on top of each other. In this case too,
The above-mentioned bonding during molding is realized, and the above-mentioned advantage (b) is achieved.
, (c). Similarly, as shown in FIG. 9(d), a plastic material piece 10 formed by simply stacking a plurality (three in the figure) of relatively thin molecularly oriented thermoplastic plastic pieces 100a may be used.

The diameter of the plastic material piece 10 is determined so that the plastic material piece 10 can be placed on the stepped portion 3c and held between the presser/base and the dowel 4, and so that a predetermined width of the flange portion 5a can be obtained. It will be done.

That is, the diameter is set to be approximately equal to the inner diameter of the inner surface 3aH of the upper cavity 3a, or to be an intermediate dimension between the inner diameter and the inner diameter of the inner surface 3b1 of the lower cavity 3b.

The piece of plastic material 10 is preferably kept at room temperature (usually 1
0-40℃), that is, without preheating.
As shown in FIG. 1, the molding is performed after being inserted into the upper cavity 3a. However, the upper limit of molecular orientation temperature (Tu)
It may be shaped after uniformly preheating to a lower predetermined temperature. The upper limit of the temperature at which molecular orientation is possible ('ru) refers to the melting point (in this specification, the upper limit of the temperature under atmospheric pressure) for crystalline thermoplastic plastics such as polypropylene, polypropylene, and high, medium, and low density polyethylene. (defined as the apex temperature of the melting endothermic curve measured by differential thermal analysis), even if it is a crystalline thermoplastic, in the case of a resin with a cold crystallization temperature such as polyethylene terephthalate, In the case of amorphous plastics such as vinyl chloride, nitrile resin, and polycarbonate resin, the crystallization temperature is determined by the liquid flow start temperature (in this specification, using a Koka type flow tester described in JIS K6719). (defined as the temperature at which the resin starts to eject a liquid flow from a nozzle with a diameter of 1 inch and a length of 10 squares when heated at a constant rate under a plunger pressure of 160 kl/car2). Further, after the sheet coming out of a sheet extrusion molding die (not shown) is cooled by a cooling roll and reaches the above-mentioned predetermined temperature, the sheet is placed on the upper surface 3d of the die 3, and the presser pad 4 is placed on the cutter. Lower the presser foot/? , lower corner 4d of y-d4 and die 3
The opening corner 3d' of the upper cavity 3a (in FIG. 1, the opening corner 3d' is a curved part, but in this case it is a right-angled part, although not shown) allows the plastic material piece to It is also possible to cut the plastic material piece 10 into 10 pieces and place the cut plastic material piece 10 on the stepped portion 3C.

Even if molding is performed at room temperature without preheating, the temperature rises due to the processing heat generated when the central portion 1 oa of the glass material piece 10 is compressed between the upper lunge 1 and the lower silanger 2, and during molding. The body wall portion and the bottom wall portion are heated to a temperature above the molecular orientation temperature (T+), which is approximately 20°C lower than the lower limit of molecular orientation temperature, and approximately 60°C higher than the upper molecular orientation temperature limit, and below. Preferably, the temperature is about 20°C higher than the lower limit of the temperature at which molecular orientation is possible.
The side surface 1b and the bottom surface 1 of the upper silansha 1 are respectively maintained at a temperature approximately 20° C. higher than the upper limit of molecular orientation temperature.
It is assumed that this is due to heat transfer due to contact with a, but in the case of the examples shown in Figures 1 to 5, the hollow molded body 5' during molding was maintained at a temperature that allows molecular orientation except for the Franz part. The present inventors have discovered. Therefore, a piece of plastic material -
It is more preferable to employ the above-mentioned molding method without preheating, which does not require the above-mentioned preheating equipment and preheating process.

At least the polymer chains of the molecularly oriented plastic forming the body wall portion 5b are oriented compared to normal melt molding,
It means a temperature at which improvements in mechanical strength, gas barrier properties, transparency, etc. are recognized as a result. For example, in the case of isotactic polypropylene, the melting point is lower, about 120
In the case of linear polyester resins such as polyethylene terephthalate, the temperature is higher than the glass transition temperature, and in the case of sticks, the temperature is higher than the glass transition temperature and lower than the liquid flow start temperature. In the case of a laminate mainly containing an ethylene-vinyl alcohol copolymer or the above-mentioned laminate, the temperature is lower than the melting point of the polyolefin resin, and (1,64M+20), where M is the latter vinyl alcohol-containing molten
Means a temperature of ℃ or higher.

The plastic hollow body 5 is manufactured using the above-mentioned molding apparatus, for example, in the following manner.

First, as shown in FIG. 1, with the upper plunger 1 and the presser foot 4 raised above the die 3, the peripheral edge 10b of the plastic material piece 10 is placed on the die 3.
It is placed on the stepped portion 3C. In this case, if the plastic material piece 10 is preheated to a relatively high temperature that allows molecular orientation, the lower cavity 3 of the plastic material piece 10
In order to prevent the softened central portion log above b from bending downward, it is preferable to arrange the upper surface 2a of the lower sylanger 2 in advance at the same level as the stepped portion 3C. Then the second
As shown in the figure, the presser pad 4 is lowered and the peripheral edge 10b of the plastic material piece 10 is pressed between the stepped portion 3C and the bottom surface 4 of the presser notch 4. It is clamped with a predetermined pressing force by b.

At least at the stage before the bottom surface 1a of the upper grunge l comes into contact with the top surface 10c of the plastic material piece 10, the above-mentioned pressing force compresses the material at the peripheral edge 10b, causing almost a flow inward in the radial direction. It is necessary to maintain the value such that the peripheral edge portion 10b is held between the stepped portions 3c without causing any damage. It is presumed that if the pressing force is excessively large as the material flows inward in the radial direction, a large shearing force is applied to the material when the upper plunger 1 descends. This is because breakage often occurs near the boundary between the wall portion and the flange portion.

After the above-mentioned clamping, as shown in FIG. 2, the upper planter 1 and the lower planter 2 are brought into contact with the center part 10a of the plastic piece 10, and while pressing the center part 10a, as shown in FIG. As shown, the upper syringer 1 and the lower syringer 2 are simultaneously lowered into the lower cavity 3b. By making the pressing force relatively high in the early stage of descent (usually the stage until reaching about 20 to 46% of the total stroke), the amount of compression of the central part 10a is increased, that is, it extends from between the two planar shafts. As shown in FIG.
The gap between the inner surface 3b' of the lower cavity and the side surface 1b of the upper plunger 1 is almost filled. That is, during the early stages of descent, material accumulates in the voids. If the pressing force is reduced and the downward movement continues after the first stage has passed, the amount of material extending from between the two syringers will decrease, and tension will be applied to the accumulated material in the barrel wall portion 5'b'. The barrel wall portion 5'b' is elongated. Therefore, in the later stage of descent after the earlier stage, the body wall part 5'b is formed by the material supplied by the stretching of the body wall part 5'b' being formed and the material extending from between the two syrangers. be done.

Therefore, when the lowering is completed and the hollow molded body 5' is formed, a gap 12 is formed between the body wall portion 5'b and the lower cavity inner surface 3b1, as shown in FIG.

By appropriately controlling the pressing force and the descending speed, a trunk wall portion 5'b having a substantially uniform thickness can be obtained. Thus 0.2
It is also possible to form the body wall portion 5'b as thin as wm. Since the pressing force at the latter stage of the descent is relatively low as described above, the wall thickness of the bottom wall portion 5'c is relatively thick (for example, approximately 1 inch or more), and therefore the corner portion 5'd due to the tension during molding. breakage is prevented. If the pressing force is kept high until the later stages of descent, the bottom wall 5/c and therefore the corner 5'd will become thinner and more likely to break, and even if they do not break, the plastic hollow body 5 may be retort heated after being sealed. During sterilization, the corner portion 5d tends to wrinkle due to thermal deformation due to the thin wall (particularly when the thickness is less than 0.3 mm).

Furthermore, the fact that the bottom wall portion 5'c is thin (approximately 1 m+ or less) weakens the deformation resistance of the plastic hollow body 5 against external force directed inward in the radial direction. The problem is that On the other hand, when molding is carried out with a relatively low pressing force from the early stages of formation, material is supplied to the body wall part during molding only from the material corresponding to the central part 10a between both plungers. Therefore, the material cannot be replenished in time for the descending speed, and a large tension is applied to the shell wall. If the temperature of the shell wall during molding is low, it is likely to break, and if the temperature is high, microcracks may occur on the surface layer. This results in the problem that the barrel wall is susceptible to whitening.

During the above-mentioned descent, the surfaces of the materials to become the bottom wall part 5C and the body wall part 5b come into contact with the upper plunger 1, which is maintained at approximately the temperature at which molecular orientation is possible (TI), and the temperature rises due to processing heat. Therefore, even if the plastic material piece 10 is not preheated and is at room temperature as described above, the material during molding is maintained at a temperature that allows molecular orientation. As mentioned above, the temperature at which molecular orientation is possible (Tl) is approximately 20°C lower than the lower limit of temperature at which molecular orientation is possible (TL), or
A temperature that is approximately 60°C higher than the upper limit of the temperature that allows molecular orientation ('ru), preferably the lower limit of the temperature that allows for molecular orientation (TL).
The upper limit of the temperature at which molecular orientation is possible (T
u) Means a temperature that is approximately 20°C higher or lower. T1
If the temperature is about 20° C. lower than TL, when the plastic material piece lO is about to be preheated, it is difficult to raise the temperature of the material being molded to a temperature at which molecular orientation is possible. On the other hand, T1 is L
If the temperature is higher than about 60° C., the temperature of the material during molding will exceed the temperature at which molecular orientation is possible, which is not preferable, not only when the plastic material piece 10 is preheated, but even when it is not preheated. Note that even if Tu<T1 or Tu is approximately 60°C,
When the molding speed is high, the contact time between the material and the upper plunger 1 is short, so it is possible to maintain the material during molding at a temperature that allows molecular orientation.

During the above molding, the inner surface 3b1 of the lower cavity and the upper surface 2a of the lower plunger 2 are heated by a built-in heater (not shown) to a temperature slightly lower than the lower limit (Tt) of the molecularly oriented plastic (typically 20 to 50°C).
) temperature, e.g. about 70-100 for polypropylene
kept at ℃. If the temperature of the inner surface 3b1 and the upper surface 2a is lower than the above temperature, it is not preferable because it becomes difficult to maintain the material during molding at a temperature that allows molecular orientation.

After the hollow molded body 5' has been formed, the upper grunger 1 is raised and, at the same time, the lower granger 2 is lowered, preferably by a small amount of .phi., for example by about 5.

This is because, as shown in FIG. 6, at the very initial stage when the upper plunger 1 has risen, the glass 8 still closes the opening of the guide hole 7 due to the time lag, and therefore the bottom surface 1a of the upper syringe 1 and the bottom end The gap 13 formed between the parts 5/e is reduced in pressure, and the bottom end part 5, which is still at a temperature that allows molecular orientation,
/c tends to deform inward, but the lower syringe 2
When it is slightly lowered, the air gap 14 between the bottom end 5/c and the upper surface 2& of the lower granger is also depressurized, and the pressure balance between the upper and lower sides of the bottom end 5'C is maintained, preventing the above deformation. This is because it can be done.

When the upper plunger 1 is further raised, the plug 8 is lowered by air pressure and the glass 8 is lowered, as shown in FIG.
Pressurized air is blown out from the gap 20 between the opening of the guide hole 7, and the hollow molded body 5' is blow-molded. b comes into close contact with the inner surface 3b1 of the lower cavity, and is cooled to a temperature υ lower than the temperature at which molecular orientation is possible, and hardened. Then, as shown in FIG. 8, a plastic hollow body 5 having a flange portion 5m, a body wall portion 5b, and a bottom wall portion 5C is formed. Thereafter, the upper shell/gloss 1 continues to rise, the presser/e-rad 4 and the lower plunger 2 are raised, and the glass hollow body 5 is extracted from the die 3. As described above, the ratio of the outer diameter to the height of the body wall portion 5b is approximately 1.5 to 3, and the thickness of the C1 body wall portion 5b is thin (approximately 01 to 03 m> and substantially uniform). Furthermore, the body wall portion 5b is transparent due to molecular orientation, and gas/Z
A plastic hollow body 5 with improved container properties such as IJ carrier is obtained. Note that if a relatively thick body wall portion 5b is required depending on the application, the thickness may be approximately 0.4 to 1. O
A plastic hollow body 5 having a body wall portion 5b with a wall thickness of wm
Needless to say, it is possible to manufacture

The flange portion 5a of the hollow silastic body 5 manufactured as described above has a thickness substantially equal to the initial thickness of the plastic material piece 10, so that it is considerably thick (approximately 2 to 2 mm thick).
6 m), and its side end surface 5a' (8th
Figure 1) is almost similar to the state of the cut surface when forming the plastic material piece 10, and therefore its surface is rough. Therefore, it is difficult to double seam the metal lid (not shown) or seam the metal collar 7° (not shown) after filling the contents. Furthermore, when a lid made of a plastic sheet or film (including a laminate with metal foil) is heat-sealed, the appearance of the side end surface 5a/ is inferior. Countermeasures for the above problems will be explained below.

FIG. 10 and FIG. 11 are drawings for explaining an example of a method of making the flange portion 5a thinner.

In FIG. 10(,), the inner diameter of the upper cavity 3'a of the die 3' is set to be slightly larger than the outer diameter of the presser pad 4 so that a gap 15 is formed.

Therefore, after the upper syranger 1 has finished lowering, the presser pad 4
(The temperature of at least the bottom surface 4b is maintained at approximately the same temperature as the side surface 1b of the upper plunger 1 by a built-in heater, not shown).
When a is compressed, the material mainly flows into the void 15, as shown in FIG.
, a flange portion 5a+ having a predetermined thickness, and a flange portion 5a/
A rising portion 5a2 that is connected to is formed. Rising part 5
a/ is removed by cutting from its base. Note that if the width of the void 15 is wide or the amount of compression is small, the rising portion 5a
' may not be formed. Note that the above compression may be performed before the upper plunger 1 descends or while descending within the lower cavity 3'b.

In FIG. 11(,), the upper surface 3"d of the die 3" is
It is approximately the same level as the bottom surface 4b of the presser foot/zorad 4,
In addition, the outer diameter of the upper cavity 3''a is set to be larger than the outer diameters of the bottom surface 4b and the flange portion 5a (both of which are approximately equal). An annular wedge-shaped small protrusion 16 is provided so that the height of the small protrusion 16 is approximately equal to the height of the flange portion 5a2 after compression. After the upper granger 1 has been lowered, the presser pad 4 presses and compresses the sifron part 5a, as shown in Fig. 11(a).
The material is the upper cavity part 3 outside the small protrusion 16.
Since the material portion 18 that has flowed into the portion 3 "a" is separated by the small protrusion 16, it can be easily separated from the formed thin flange portion 5a2. is the same as in the case of FIG.

FIG. 12 shows the side end surface 5. of the flange portion 5a. / and bottom surface 5a'', the first
As shown in Figure 2(a), the upper surface 3"'d of the die 3"'
A recess 20 having a shape substantially corresponding to the lower half of the flange portion 5a3 after shaping is formed on the inside of the flange portion 5a3, and a protrusion for holding the flange portion 5a (peripheral portion 10b) at the innermost side of the recess portion 20. A portion 20a is formed. On the other hand, the presser foot/hood 4' is provided with a flange part 4'a, and on the inside of the lower surface 4'a' of the flange part 4/a, there is approximately the upper half of the side surface of the flange part 5a3 after shaping. A recessed portion 21 having a side surface 21a having a shape corresponding to that of the recessed portion 21 is formed. Recess 21
The upper surface 21b is a plane whose width is slightly wider than the width of the flange portion 5a. Therefore, after the upper plunger l has finished descending (in the case of Fig. 12), or before or during its descent, the presser pad 4' causes the die 3///d and the lower surface 4'a' of the presser pad's flange to be By slightly pressing the flange portion 5a until they come into contact, a flange portion 5a3 whose side end surface 5a' and bottom surface 5a'' are shaped as shown in FIG. 12(b) can be obtained.

Although not shown, while the upper plunger 1 is descending in the lower cavity 3b, more preferably in the latter stage of its descent, the pressing force of the presser foot/glad 4 is increased to compress the peripheral edge portion 10b, thereby compressing the flange portion 5a. You may try to make it thinner. As shown in FIG. 5, after the molding of the hollow molded body 5' is completed, the flange portion 5a is pressed and compressed by the presser/gurad 4, and at the same time, the height of the body wall portion 3b increases due to the compression. The thickness of the flange portion 5a can also be reduced by lowering the upper syringe/jar 1 and the lower syringe 2 by the same amount. When compressing or shaping the flange portion as described above, the plastic material piece 10 does not necessarily have to be circular; for example, even if it is a regular polygon (for example, a regular hexagon), the flange portion with a circular outer periphery may be used. It is possible to obtain. In these cases, the bottom surface 4b of the presser foot base 4,
The temperature of the side surface 21a1 of the upper surface 21b of the concave portion 21 of the presser foot 4' is maintained at approximately the same temperature as that of the side surface 1b of the upper granger 1.

In the above example, the manufacturing method of a plastic hollow body with a cylindrical body wall was described, but it is also possible to manufacture a plastic hollow body with a body wall of any shape such as a square with rounded corners. Needless to say, this can be easily obtained by changing the .

Furthermore, the introduction of the plastic material piece into the center of the die cavity is carried out by the upper plunger 1 and the lower sill/jar 2.
This may be done by simultaneously raising the die 3 and the presser pad 4 without substantially moving the die 3 (although there may be some movement due to the suppression). Further, although not shown, pressurized air (pressurized fluid) may be blown into the hollow molded body 5' from the side surface 1b of the sylanger 1.

According to the present invention, the upper plunger descends and contacts the central part of the piece of plastic material in order to introduce the central part into the die cavity while compressing the material in the central part of the piece of plastic material by the upper plunger and the lower plunger. Previously, since the material at the peripheral edge of the plastic material piece does not flow inward in the radial direction, there is no risk of breakage occurring near the boundary between the body wall and the 7-edge part of the hollow molded body. have

This has the effect of providing a plastic hollow body with improved container properties such as resiliency and strength.

In addition, since the body wall is formed from the material that is compressed and expanded while in contact with the side surface of the upper Glossy, which is maintained at a temperature near the temperature that allows for molecular orientation, the plastic material piece is kept at room temperature without being preheated. Even when molded from scratch, it has the advantage that it is possible to obtain a can-shaped glass hollow body having a body wall with molecular orientation and a large height to diameter without breaking.

Furthermore, since the plastic material pieces are formed by multiple cutting into sheets or films of substantially uniform thickness, the cost is lower and mass production is superior compared to forming the plastic material by injection molding or the like. It has the advantage of being

Examples will be described below.

Example 1 Melt flow index (measured at 230°C) is 0, 9
A blank with a diameter of 60 cm was punched out from a 3-thick polypropylene sheet having a melting point (differential calorimeter method) of 164 DEG C. and a melting point of 164 DEG C. (differential calorimeter method). In the device shown in Figure 1, there is an upper sylunger (diameter 51.4 m), a lower plunger (
diameter 53.0 tea), lower cavity (inner diameter 5
3.05 ms) surface temperature was 155 °C and 100 °C, respectively.
It was preheated to 75°C using an internal heater.

The polypropylene blank was placed in the upper cavity at room temperature (30° C.) as shown in FIG. 1, and the periphery of the blank was clamped by a pressure pad of 10 kg/cm 2 . After that, while applying a small pressure of 1120 kg 7cm2 to the center of the blank in the upper and lower sylangers, the center of the blank was moved into the lower cavity by 50 W.
Introducing at a speed of m/s, and reducing the pressure in the center of the blank to 200 m/sec at a position where the lower plunger tip is 25 m+ from the upper end of the lower cavity, until the lower plunger tip is 100 m+ from the upper end of the lower cavity. I did the molding.

After that, while raising the upper syranja, 10kfl/c
Air at a pressure of m2 was introduced, and the body wall surface of the molded container was moved from the side surface of the upper sylanger to the surface of the lower cavity, thereby cooling and assimilating the body wall portion and the bottom wall portion. Thereafter, the presser/hood and lower silanja were raised to obtain an extremely transparent container with a body wall thickness of 0.3 m and a height of 99 mash.

Example 2 Two blanks with a diameter of 60 cm were prepared by punching out polyzoropyrene 7-metal having a melt flow index of 0.4 g/10 minutes and a melting point of 163° C. and a thickness of 1+ m. Furthermore, the melt flow index is 6g/10ffi and the melting point is 165.
The innermost layer is teripropylene (4) with a melting point of 162°C.
Adhesive layer of maleic anhydride-modified polyglobylene (B),
Vinyl alcohol content is 70 molt and melting point is 1
Thickness l of A/B/C/B/A configuration with a single layer of 82°C ethylene-vinyl alcohol copolymer (C) as an oxygen barrier
(1) Blanks each having a diameter of 60 mm were punched out from a symmetrical 5-layer laminated sheet of (the CV thickness of the ethylene-vinyl alcohol copolymer layer as an oxygen barrier layer was approximately 85 μm), and each was heated to 155° C. with oat.

The three heated blanks were placed one on top of the other with the polypropylene blanks on both sides in the upper cavity of the same device as in Example 1 (the upper syringe, etc. were also preheated to the same temperature as in Example 1), and the presser was pressed.・10 by Grado
The periphery of the blank was clamped at a pressure of 1.5 kg/cm2. After that, while applying a pressure of 320 kg 7 cm2 to the center of the syringe blank by the upper planar and lower lunge, the center of the blank was introduced into the lower cavity at a speed of 50 m/sec, so that the tip of the lower syringer was 25 m/sec from the upper end of the lower cavity.
Pressure at the center of the blank at position m is 90 In 7 cm.
2, molding was carried out until the tip of the lower plunger was 100 mm from the upper end of the lower cavity.

Then, while raising the upper plunger, 10 to 9/c
Air at a pressure of rn was introduced to move the body wall surface of the molded container from the side surface of the upper plunger to the surface of the lower cavity, and the body wall portion and the bottom wall portion were cooled and solidified.

Furthermore, the presser pad and the lower plunger were raised to obtain a container with a body wall thickness of 0.3 m and a height of 99 m, with excellent transparency and excellent oxygen barrier properties. The trunk wall and bottom wall were completely adhered even though three blanks were stacked and molded.

[Brief explanation of the drawing]

FIG. 1 is an explanatory longitudinal cross-sectional view of an example of a tool used in carrying out the present invention, FIG. 2 is a longitudinal cross-sectional view showing the state immediately before molding of a plastic hollow body by the tool of FIG. 1, and FIG. 2 is a cross-sectional view taken along the line I-III, FIG. 4 is a longitudinal sectional view showing the early stage of forming using the tool shown in FIG. 1, and FIG. 5 is a completed compression stretch forming using the tool shown in FIG. 1. 6, 7, and 8 are longitudinal sectional views showing the state at the time when the hollow molded body is formed by blow molding, respectively, immediately before, during, and after blow molding the hollow molded body in Figure 5. A vertical cross-sectional view showing the later state,
Fig. 9 is a vertical cross-sectional view of plastic material pieces formed by overlapping each other, and Fig. 9(a) is a case where different types of single plastic pieces are overlapped, and Fig. 9 (color) is a laminate piece and a single plastic piece. Fig. 9(C) is a drawing showing a case in which pieces of a laminate are overlapped, and Fig. 9(d) is a drawing showing a case in which single pieces of the same type of plastic are overlapped.
FIG. 0 is a vertical cross-sectional view of a main part of a first example of a tool capable of forming a thin flange portion used in carrying out the present invention, and FIG.
0 (a) is a drawing showing the state before the flange is compressed, FIG. 10 (b) is a drawing showing the state after the flange is compressed and made thinner, and FIG. FIG. 11(b) is a longitudinal cross-sectional view of a main part of a second example of a tool capable of forming a thin-walled flange portion, in which FIG. FIG. 12 is a longitudinal cross-sectional view of a main part of an example of a tool capable of forming a shaped flange used in the practice of the present invention; Figure 72(a) is a drawing showing the state before pressing the flange part, Figure 72(b)
is a drawing showing the state after the flange portion has been pressed and shaped. /... Upper franchisor (first plunger), /a...
・Bottom surface, /b...Flight 1 side, 2.Lower plunger (second plunger), 3b...Lower (dice) capitei,
3b...Inner side! ...Plastic hollow body, S/,
,,Hollow molded body! ; a % S a, + S ax
, 3 FLr-75 section,! b... body wall part, 5c
...Bottom wall part, IO...Plastic material piece, 10a...
central part, 10b... peripheral part. Figure 1 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 100° (b) +01 (c) (d) Figure 10 Figure 11 (b)

Claims (7)

[Claims] (1) In a method for producing a hollow plastic body having a flange portion, a body wall portion, and a bottom wall portion, at least the body wall portion having molecular orientation, the method includes a flat, molecular-oriented body having a substantially uniform thickness. The periphery of a piece of molecularly oriented plastic material whose temperature is below the upper limit of the orientable temperature is held, and the central part corresponding to the bottom wall is held between a first granger and a second sylanger. The material of the plastic material piece extending from between the first plunger and the second plunger is introduced into the die cavity while being compressed to bring the body wall portion to a temperature that allows molecular orientation. A hollow molded body is formed by contacting the side surface of the held first syringer, and then, while returning the first syringer, pressurized fluid is introduced into the inside of the hollow molded body. The hollow plastic body is characterized by being sent out to inflate the body wall portion, and to be cooled and hardened by contacting the inner surface of the die skievity, which is maintained at a temperature lower than the lower limit of the molecular orientation temperature. manufacturing method. (2) A method for manufacturing a plastic hollow body having a flange portion, a body wall portion, and a bottom wall portion, at least the body wall portion having molecular orientation, wherein the plastic hollow body has a substantially uniform thickness, is flat, and has molecular orientation. The peripheral edge portion corresponding to the flange portion of a piece of molecularly oriented plastic material whose temperature is below the upper limit of possible temperature is clamped, and the central portion approximately corresponding to the bottom wall portion is compressed by the granger of the first sylanger j2. The material of the plastic material piece extending from between the first sylanger and the second syringe is introduced into the die cavity, and the material of the plastic material piece is maintained at a temperature that substantially allows molecular orientation of the body wall. A hollow molded body is formed by forming the hollow molded body so as to be in contact with a side surface of the first plunger, and then, while the first plunger is returned, pressurized fluid is sent into the inside of the hollow molded body. The body wall portion is brought into contact with the inner surface of the die cavity, which is maintained at a temperature lower than the lower limit of the molecular orientation temperature, to be cooled and hardened, and before the central portion is introduced into the die cavity. or during introduction or after forming the hollow molded body, the peripheral edge is compressed so that the material flows primarily radially outward to form a thin-walled or shaped flange. A method for manufacturing a hollow glass body. (3) A method for manufacturing a hollow glass body having a flange portion, a body wall portion, and a bottom wall portion, at least the body wall portion having molecular orientation, in which a flat, molecular structure having a substantially uniform thickness is provided. A peripheral edge portion corresponding to the flange portion of a piece of molecularly oriented plastic material whose temperature is below the upper limit of the orientable temperature is held between the first sylanger and the second plunger. The material of the plastic material piece extending from between the first syringer and the second syringe is introduced into the die cavity while being compressed, and the material of the plastic material piece is brought to a temperature at which the body wall portion can be substantially oriented in molecular orientation. forming a hollow molded body by forming the hollow molded body in contact with the side surface of the first syringe held in the body, and then compressing the peripheral edge so that the material flows toward the body wall, and at the same time The first sylanger and the second grunge are further introduced into the die cavity, and the upper part of the body wall of the hollow molded body is additionally formed by the flowing material, and then the first silunger is introduced into the die cavity. While returning the hollow molded body, pressurized fluid is sent into the inside of the hollow molded body to inflate the body wall portion and bring it into contact with the inner surface of the die cavity, which is maintained at a temperature lower than the lower limit of the molecular orientation temperature. A method for manufacturing a hollow body characterized by cooling and hardening. (4) A method for manufacturing a plastic hollow body having a flange portion, a body wall portion, and a bottom wall portion, at least the body wall portion having molecular orientation, wherein the plastic hollow body has a substantially uniform thickness, is flat, and has molecular orientation. The periphery of the molecularly oriented glass material piece, which is at a temperature below the upper limit of possible temperature, is held between the edges corresponding to the flange, and the center portion, which approximately corresponds to the bottom wall, is held by a first granger and a second plunger. The plastic material is introduced into the die cavity while being compressed, and the material of the glass material extending from between the first plansha and the second plansha is brought to a temperature that substantially allows molecular orientation of the body wall. A hollow molded body is formed by forming it in contact with the side surface of the held gransha, and during the introduction, the peripheral edge is compressed so that the material flows toward the body wall. The upper part of the body wall of the hollow molded body is formed using the flowing material, and then, while returning the first syringe, pressurized fluid is sent into the inside of the hollow molded body to form the body wall part. A method for producing a hollow plastic body, characterized by: inflating it, bringing it into contact with the die cavity or inner surface, which is maintained at a temperature lower than the lower limit of the molecular orientation temperature, and cooling and hardening it. (5) A method for manufacturing a hollow plastic body according to claim 1, 2, 3, or 4, in which the plastic material pieces are made by overlapping plastic sheets or films of the same or different types. . (6) The method for manufacturing a plastic hollow body according to claim 1, 2, 3, or 4, wherein the temperature of the plastic material piece is room temperature. (7) In the early stage of introducing a piece of plastic material into the die cavity, the compressive force by the first and second glanders is relatively increased to force the extending material between the first planter and the inner surface of the die cavity. The plastic hollow according to claim 1, 2, 3, or 4, which accumulates the material so as to substantially fill the void of the material, reduces the compression force of the hindlimb, and stretches the accumulated material. How the body is manufactured.