JP2544615B2 - Biaxially stretched blow molding parison and molding method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to molding of bottle necks, and more particularly to a synthetic resin container, particularly a polyisylene terephthalate biaxially stretch blow molded container molding parison, and the same. It relates to a molding method.

[Conventional technology]

In order to improve various properties (heat distortion resistance, chemical resistance, strength, etc.) of bottles that cannot be stretched, (i) a method of heating and crystallizing the bottles, (ii) polycarbonate, polyarylate, etc. A method of co-injecting a heat-resistant resin or the like with a main resin to crystallize the heat-resistant resin, (iii) a method of molding the heat-resistant resin or the like in two colors to form a bottle mouth, or (iv) using a heat-resistant resin A method has been used in which the outer peripheral portion of the bottle mouth is preformed, and the bottle is made by insert molding using this preformed product.

[Problems to be solved by the invention]

However, in the case of the above method (i), the shape of the bottle is likely to be deformed during the heating crystallization. As a result, a bottle mouth with poor sealing property may be obtained. In addition, the screw thread, screw root diameter, top surface shape and dimensions of the seal portion of the bottle mouth are not stable.

Further, since it becomes opaque by crystallization, it cannot be applied when a transparent feeling is required for the entire bottle.

Further, since another step for crystallization is required, productivity is poor.

Next, in the above method (ii), the main resin, polyethylene terephthalate, and the functional resin are co-injected and melted and injected from a position corresponding to the bottom of the container by co-injection.
The functional resin remains in areas other than the bottle mouth, such as the shoulder, body, and bottom of the container, and the resin is concentrated in the bottle to provide a bottle with excellent functionality. I can't make it.

For this reason, the functional resin is also distributed in areas other than the bottle neck portion, which makes it difficult to perform stretch blow molding (especially in the case of poor stretch moldability, in the case of resin, uneven wall thickness of containers or whitening etc. Molding becomes difficult because it easily occurs in the process).

Moreover, since an expensive functional resin is generally used as a material, there is a drawback that the manufacturing cost becomes high.

Next, the above methods (iii) and (iv) have a drawback that the adhesiveness between the main resin and the functional resin is not sufficient. Further, in the case of the above method (iii), a plurality of molding dies are required and the molding product or the dies are moved, which complicates the process. Also in the case of the above method (iv), a plurality of molds are required, and an insert device and the like are indispensable, which also has a drawback that the process becomes complicated.

Therefore, the problem to be solved by the present invention is to solve the above-mentioned drawbacks, and the functional resin in the bottle mouth portion, in which the bottle mouth portion is composed of one or more kinds of functional resin and the main resin constituting the container body portion, Another object of the present invention is to provide a bison stretch blow molding parison having a bottle mouth portion and a method for molding the same, in which the interfacial adhesion of the main resin is improved.

[Means for solving problems]

The present inventor, as a result of research to solve the above problems,
It has a brim-shaped protruding ring part connected to the lower end of the mouth part, and has one or more functional resin gates on the outer peripheral part of this protruding ring part, and also has a main resin gate on the bottom part, Between the portion corresponding to the bottle body portion and the portion corresponding to the bottle body portion via the transition portion, there is a throttle portion, the cross-sectional area of this throttle portion is smaller than the cross-sectional area of the lower end of the mouth portion, and the bottle Set a parison shape with a value smaller than the cross-sectional area of the part corresponding to the body, from the main resin gate at the position corresponding to the bottom of the parison, inside the cavity, from the cavity area corresponding to the protruding ring part of the parison. The main resin is injected until the lower cavity region is filled, and it is detected that the flow end surface of the main resin reaches the cavity corresponding to the narrowed part of the parison and the main resin pressure rises. The functional resin gate is located at a position corresponding to the outer periphery of the protruding ring portion of the Son, and injection of the functional resin is started in the radial direction into the cavity area corresponding to the protruding ring portion. Are simultaneously or sequentially or alternately injected, and the bottle mouth portion consisting of the protruding ring portion and the mouth portion is formed into a multi-layer structure of at least two layers in which the interface between the main resin and the functional resin is intricately shaped. The present invention has been completed based on the finding that a parison in which the portion corresponding to the bottle body and the transition portion is formed of only the main resin can be molded.

That is, the first invention is "a bottomed cylindrical parison for biaxial stretch blow molding, having a collar-shaped protruding ring portion connected to the lower end of the mouth portion, and the outer peripheral portion of the protruding ring portion is functional. It has one or more resin gates, and also has a main resin gate on the bottom part, between the protruding ring part and the part corresponding to the bottle body, in the part corresponding to the bottle body through the transition part. There is a connected throttling part, and the cross-sectional area of this throttling part is set to a value smaller than the cross-sectional area of the lower end of the mouth part and smaller than the cross-sectional area of the part corresponding to the bottle body part, and the mouth part and the protruding ring. For biaxial stretch blow molding, characterized in that the part has a multi-layered structure of two or more layers of functional resin and main resin, and the part corresponding to the bottle body and the transition part are formed of only the main resin. Parison. ] Is the gist.

Next, a second aspect of the present invention is "a mouth and a flange-shaped protruding ring portion connected to the lower end thereof, and a portion corresponding to the bottle body portion located below the flange portion, and a portion corresponding to the protruding ring and the bottle body portion. There is a throttling part connected to the part corresponding to the bottle body through the transition part, the cross-sectional area of this throttling part is smaller than the cross-sectional area of the lower end of the mouth part, and the cross-section of the part corresponding to the bottle body part. Using an injection mold with a cavity corresponding to the parison shape set to a value smaller than the area, from the main resin gate at the position corresponding to the bottom of the parison into the cavity, the protrusion of the parison The process of injecting the main resin until the cavity region below the cavity region corresponding to is filled, and the flow end surface of the main resin reaches the cavity region corresponding to the narrowed portion of the parison, When a rise in the oil pressure inside the cavity is detected, the process of radially injecting into the cavity area from the functional resin injection gate located at the position corresponding to the protruding ring of the parison, and then continuing to the main resin After or without stopping the injection, the functional resin and the main resin are simultaneously or simultaneously or alternately injected to form at least the main resin portion to be inserted into the protruding ring, and at the same time, the main resin is formed. A method for molding a parison, characterized in that a layer is stretched and formed along a core portion and an interface between a functional resin and a main resin is indefinite. ] Is the gist.

Hereinafter, the present invention will be described in detail with reference to the drawings.

 FIG. 1 shows the whole parison according to the present invention.

The parison (1) of the present invention comprises a bottle mouth portion (1 ') composed of a mouth portion (2) and a protruding ring portion (3), and a portion (6) corresponding to a bottle body portion which becomes a bottle body portion by biaxial stretching blow. ), The narrowed portion (7), the main resin gate (4), and the functional resin injection port (5) are provided on the outer circumference of the protruding ring portion (3).

More specifically, as shown in FIG. 2 (a), the thickness of the portion (6) corresponding to the bottle body is t _o , the radius from the center of the parison to the center of the wall thickness is r _o , and the constricted portion ( The wall thickness of 7) is t ₁ , the radius from the center of the ballison to the wall thickness center is r ₁ , and the protruding ring part (3)
The thickness of the lower end (8) of the mouth where the mouth and the mouth (2) connect is t ₂ ,
Letting the radius from the center of the parison to the center of the wall thickness be r ₂ , the resin flow path cross sections at these positions, S ₀ = 2πr _o t _o , S ₁ = 2πr ₁ t ₂ , S ₂ = 2πr ₂ t ₂ , ₂ > S ₁ and S ₀ ≧ 2S ₁ are set.

Further, t ₂ > t ₁ > 0.3 mm and 5.0 mm> t ₀ > t ₁ are set.

As shown in FIGS. 2 (a) to 2 (d), the parison according to the present invention gradually increases in wall thickness via the transitional portion (9) between the portion (6) corresponding to the bottle body and the throttle portion (7). It is going to be smaller.

Alternatively, it has a transition portion (9 ') between the throttle portion (7) and the protruding ring portion (3) as shown in FIG. 2 (e).

There are various shapes of the transition part (9) as shown in FIGS. 2 (a) to (d). Among them, the part (6) corresponding to the bottle body part in terms of mold releasability and mold production. The shapes shown in FIGS. 2 (a) and 2 (c), which do not cause so-called undercut, are preferable.

Further, when the protruding ring portion (3) is made to function as a support ring at the time of filling the bottle, after the biaxial stretch forming under the ring, as shown by the dotted line in FIG. 2 (c), the mouth portion (8) is formed.
It is possible to form an outer periphery that is substantially the same as the outer periphery of

Next, the narrowing section and the bottle section, which are the main parts of the parison of the present invention, will be described.

 FIG. 4 (d) shows an example of the parison of the present invention.

The main resin (21) constitutes the part corresponding to the bottle body,
(21a) is a transition section, and (22b) is a diaphragm section. In the protruding ring portion (3), the functional resin (22a) is formed on the outer circumference, while the main resin (21c) is formed along the core type wall surface. Even if placed on the mouth (8), the functional resin (26
b) is formed on the outer circumference, and the main resin (21d) is formed along the core type wall surface. And functional resin (26b),
An amorphous interface (23) is formed between (22a) and the main resin (21d) and (21c).

 FIG. 5 (a) shows another example of the parison of the present invention.

In this example, the intricate interface (23a) is formed, and the intricate functional resin (22d) wraps around the main resins (21f) and (21e) and the core mold surface ( 22e) and a multiple structure.

Further, FIG. 5 (b) shows still another example of the parison of the present invention.

A separate interface (23b) is formed by the main resin layer (21g) formed on the outer periphery of the bottle mouth, and the main resin layer is divided into two or more layers. The functional resin layer (22f) is formed.

As illustrated above, the parison according to the present invention features an amorphous interface. Thus, this amorphous interface exists in the narrowed portion, the transition portion from the narrowed portion to the protruding ring portion, and the bottle mouth portion, and the portion corresponding to the bottle body portion and the portion corresponding to the bottle body portion It does not exist at the transition to the diaphragm.

That is, a portion corresponding to the bottle body portion and a transition portion from the portion corresponding to the bottle body portion to the narrowed portion are formed by only the main resin.

Next, regarding the molding method of the parison of the present invention, FIG. 3 showing a mold, and FIG. 4 showing the molding process of the parison.
A description will be given with reference to FIGS.

A main resin is injection-molded from a main resin injection nozzle (13) into an injection mold having cavities formed by a core mold (10), a lip mold (11), and a cavity mold (12), and FIG. As shown in a), the main resin (2
1) is flowed into the cavity area of the part corresponding to the bottle body, and when the resin flow front surface reaches the cavity area of the throttle part, the cross-sectional area of the flow passage extends from the cavity area of the transition part to the cavity area of the throttle part. By rapidly reducing the pressure, the resin internal pressure rises sharply. This sudden rise is detected by a main resin flow path (not shown) in the injection mold, a resin sensor provided in the cavity, or an injection ram pressure detection sensor that rises as the resin pressure rises. Grasping as the timing to start flowing into the mouth, the functional resin injection nozzle (14) injection-molds the functional resin, and the radius from the functional resin injection gate (5) provided with at least one protruding ring. The functional resin (22) is caused to flow in the direction. (Fig. 5 (b)) Subsequently, as shown in Fig. 4 (c), the main resin (2
1) and the functional resin (22) are simultaneously injected and filled in the bottle mouth, the main resin is stretched inward along the core mold wall surface, and via the functional resin and the amorphous interface (23). The main resin inner layers (21c) and (21d) that are connected together are formed.

During this molding process, the functional resin is pushed by the main resin that flows in under pressure from the throttled portion, and as a result, flows toward the lower end of the mouth that has a wider flow passage cross section than the throttled portion and crosses the throttled portion. Therefore, it does not flow to the part corresponding to the bottle body or the transition part.

Thus, in the present invention, polyethylene terephthalate resin can be used as the main resin.

The polyethylene terephthalate resin used in the present invention means terephthalic acid or its ester-forming derivative (for example, lower alkyl ester, phenyl ester, etc.) and ethylene glycol, or its ester-forming derivative (for example, monocarboxylic acid ester, ethylene oxide, etc.). Is a polyester obtained by polymerizing and
Less than about 20 mol% of other dicarboxylic acids or glycol moieties may be copolymerized. Further, the polyester may be copolymerized with a polyfunctional compound such as trimethylolpropane, pentaerythritol, trimellitic acid and trimesic acid in the range of 2 mol%. Examples of the other dicarboxylic acid used as the copolymerization component include aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, naphthalene dicarboxylic acid and diphenyldicarboxylic acid, adipic acid,
Examples thereof include fatty acids such as sebacic acid, azelaic acid, decanedicarboxylic acid, cyclohexanedicarboxylic acid, and alicyclic dicarboxylic acids.

As the other glycol component used as the other copolymerization component, an aliphatic such as trimethylene glycol, propylene glycol, tetramethylene glycol, neopentyl glycol, hexamethylene glycol, dodecamethylene glycol, cyclohexanedimethanol, or the like, or Examples thereof include alicyclic glycols, bisphenols, hydroquinone, 2.2-bis (4-β-hydroxyethoxyphenyl) propane and other aromatic diols.

Further, it is also possible to use other oxyacids such as p-hydroxyethoxybenzoic acid and α-oxycaproic acid. It is also possible to use lower alkyl esters of these oxyacids and other ester-forming derivatives.

Next, as a functional resin, polyacetal, polyamide such as nylon 6, nylon 66, polycarbonate ,.
Aromatic polyesters such as polyphenylene oxide, polyphenylene sulfide, polysulfone, polyether sulfone, polyarylate, phenol aralkyl resin, polyether ether ketone, polyetherimide, and U polymer (Unitika polyarylate and polyethylene terephthalate blend polymer) , A blended polymer of polycarbonate and polyethylene terephthalate, a blended polymer of polyarylate and polycarbonate and polyethylene terephthalate, and other than the above polymers, continuous fibers such as glass fiber, carbon fiber, SiC fiber, alumina fiber and silica fiber, Al ₂ O ₃ , SiC, Si ₃ N ₄ ,
It is possible to apply whiskers such as graphide, Cu, Cr, Fe and Ni, and polyester resin mixed with a reinforcing material such as mica and potassium titanate, or a composite material of the above functional resins.

Next, as a functional resin injection gate, as in the embodiment described later, a ring sprue connected to a hot runner via a primary gate is used to form a film gate or a partial film gate over the entire circumference, or a predetermined area over the entire circumference. Any one or many pin gates that are evenly distributed at intervals can be applied.

Further, in the former case, the gap size of the film gate or the cross-sectional area of the pin gate can be changed depending on the position of the primary gate to make the inflow amount uniform due to the sprue pressure loss.

In the present invention, the injection position of the functional resin is set to a position corresponding to the outer peripheral article of the protruding ring portion of the parison, and the injection opening timing of the functional resin is adjusted when the flow front end surface of the main resin reaches the narrowed portion of the parison. The reason is that by doing so, the residual air in the cavity is trapped between the functional resin and the main resin, and it is prevented from becoming bubbles after molding and remaining at the mouth of the molded body. This is because the resin is limited in the area above the narrowed portion.

In addition, the functional resin is injected in the cavity in the radial direction because the functional resin is injected in the radial direction, in a ring shape, or at a number of circumferential points at the same time, and then flows upward. As a result, the molding strain of the mouth and the uneven distribution of the functional resin in the circumferential direction are not generated, and by allowing the functional resin to flow in such a manner, the weld is welded to the upper end of the mouth. This is because the occurrence of lines is prevented, there are no molding defects (such as sink marks and air bubbles) at the mouth, and the dimensional accuracy important for the sealing property of the container is obtained.

[Action]

(I) The flow cross-sectional area of the resin is gradually narrowed from the portion corresponding to the bottle body through the transition portion, and the bottle mouth portion is provided through the throttle portion having the flow cross-sectional area of the resin narrowed to at least 1/2 or less. Due to the connection to the portion corresponding to, the abrupt resin pressure increase in the cavity occurs in the process in which the tip of the main resin flow passes from the portion corresponding to the bottle body to the throttle portion. This rise in pressure is detected by the main resin flow path (not shown) between the injection molds, the resin sensor provided in the cavity, or the injection ram pressure detection sensor that rises as the resin pressure rises. The obtained result is effectively used for setting the injection start timing of the functional resin.

(Ii) The throttle has a flow cross-sectional area smaller than the lower end of the mouth,
In addition, since the thickness of the throttle portion is 0.3 mm or more, the main resin flow pressure passing through the throttle portion can be made higher than the combined pressure of the functional resin and the main resin passing through the lower end portion of the mouth. As a result, the functional resin is prevented from flowing into the cavity region of the portion corresponding to the bottle body portion, and the portion corresponding to the bottle body portion can be constituted by only the main resin.

(Iii) In the process of simultaneously injection-molding a large number of parisons, the transfer speed of each tip of the main resin flow that is inevitably generated due to mold precision, resin flow channel temperature, non-uniformity of the physical properties of the molten resin, etc. It acts to correct the deviation of the filling time due to the difference up to the narrowing portion from when the leading edge of the resin flow in the main resin flow divided into each cavity reaches the narrowing portion.

That is, in the cavity where the resin flow is the first,
The resin pressure in the cavity sharply increases, and as a result, the resin inflow amount into the cavity sharply decreases, so that the main resin inflow pressure increases toward the remaining unreached cavities, and the resin inflow amount increases. As a result, the filling speed of the cavities that are delayed in filling is increased, and the arrival of the cavities that are delayed next in time is accelerated.
The resin flow reaches the throttled portion of the cavity with the longest delay at an accelerated speed, and as a result, the gap in the filling time is shortened.

Also, since the amount of main resin that passes through the throttle portion and flows into the mouth portion is limited by the throttle portion and is small, the cavity region of the mouth portion is filled with the main resin while the above-mentioned iming correction is performed. It is prevented from falling.

(Iv) The main resin flow and function that flows near the center of the cavity due to the unevenness of the mold surface of the outer peripheral surface molding mold, so-called lip mold, which has the unevenness of the screw, locking ring, etc. The resin exhibits a wavy shape.
A structure in which the interface between the functional resin flow and the main resin is intricate is obtained.

〔Example〕

Example 1 Portion corresponding to bottle body t ₀ = 4.2 mm, S ₀ = 372 mm ² , r ₀ = 14.1 mm, throttle part t ₁ = 1.2 mm, S ₁ = 118 mm ² , r ₁ = 15.6 mm, mouth Lower end t ₂ = 2.4 mm, S ₂ = 241 mm ² , r ₂ = 16 mm 38 mmφ caliber thread size, locking ring mouth, and 44 mmφ outer circumference protruding ring, bottom center A mold having a gate for injecting the main resin and a film gate for injecting the functional resin on the outer peripheral portion of the protruding ring is used as a parison injection molding die, and polyethylene terephthalate (IV value of 0.
80 Mitsui PET resin JI25), U polymer (Unitika U8400, blend polymer of polyarylate and polyethylene terephthalate) is used as functional resin, and polyethylene terephthalate injection unit cylinder temperature
270-280 ℃, U polymer injection unit cylinder temperature is 285-290 ℃, mold temperature is 10 ℃ for cavity mold
The temperature of the core mold was adjusted to 17 ° C, and the temperature of the lip mold was adjusted to 40 ° C.

Injection of polyethylene terephthalate Ram pressure 120kg / cm ²
Set the injection speed (oil flow rate adjustment%) to 3 steps (20
%, 25%, 23%) and controlled injection, ram pressure is 70kg / c
When it reached m ² , it stopped for 0.1 seconds, and at the same time as it stopped, the U polymer was injected at a ram pressure of 120 kg / cm ² and an injection speed of 90%.
Injection-filled with g.

Then, the cylinder stroke of the U polymer was cut off, and the injection of polyethylene terephthalate was restarted.
After restarting the injection of polyethylene terephthalate, the holding pressure was changed to a temporary holding pressure of 80 kg / cm ² and a secondary holding pressure of 30 kg / cm ² .

As a result, it was possible to obtain a parison with a weight of 67 g in which 75% by weight of U polymer was concentrated and distributed to the bottle mouth.

Then, the obtained parison is biaxially stretch blow molded,
By subsequent heat treatment, a bottle with excellent heat resistance could be obtained. 0.4 kg / cm of this bottle with hot water at 85 ℃
^{It was} filled with hot water under a counter pressure of ² , then capped, sterilized by inversion for 30 seconds, and then cooled. After a while
When the contraction of the inner diameter of the mouth and the opening torque were calculated, the inner diameter torque of the opening was 0.15 mm or less, and the opening torque was 20 kg cm to 30 kg cm.
It was found that the heat filling performance was excellent.

Example 2 Portion corresponding to bottle body t ₀ = 4.0 mm, S ₀ = 239 mm ² , r ₀ = 9.5 mm, narrowing part t ₁ = 1.0 mm, S ₁ = 69 mm ² , r ₁ = 11 mm, mouth bottom end Part t ₂ = 2.16 mm, S ₂ = 155 mm ² , r ₂ = 11.4 mm with 28 mmφ diameter thread, locking ring mouth, and outer circumference 41 mmφ protruding ring, centered on the bottom. A mold having a gate for injecting the main resin and a pinpoint gate for injecting the functional resin on the outer periphery of the protruding ring was used as a parison injection molding die, and polyethylene terephthalate (IV value 0.80 Mitsui PE
T resin J125), polycarbonate (Teijin Kasei, Panlite L1225T) as the functional resin, and the polyethylene terephthalate Brent polymer (PC / PET blend polymer) (blend ratio 35:65) were used.

Polyethylene terephthalate injection cylinder temperature 26
5 to 270 ℃, PC / PET blend polymer injection unit Cylinder temperature is 290 to 300 ℃, mold temperature is controlled by the cavity mold and core mold with cold water of 15 ℃, and the lip mold is 30 ℃ during injection molding. I adjusted the temperature.

Polyethylene terephthalate injection ram pressure 120kg / cm ²
Set, ram pressure stops 0.05 seconds when it reaches the 70 kg / cm ^2, injection ram pressure simultaneously blend polymer and stop
6 g was injected and filled at 120 kg / mm ² and an injection speed of 95%.

The injection cylinder stroke of PC / PET blend polymer was cut off, and after the injection of polyethylene terephthalate was restarted, the primary holding pressure was 100 kg / cm ² and the secondary holding pressure was 30 kg / cm ² .

As a result, a parison with a weight of 60 g, in which the PC / PET blend polymer was concentrated and distributed about 70% by weight to the bottle mouth, was obtained.

This parison was biaxially stretch blow molded, heat treated and 1.
After making it into a bottle of 5, fill it with hot water at 85 ° C and seal it with a 28 mm aluminum screw cap,
When the inner diameter contraction of the mouth and the opening torque were obtained for a second, the opening torque of 20 to 30 kg / mm when the inner diameter contraction was 0.1 mm or less,
It was found that the thermal filling performance was good.

〔The invention's effect〕

As described in detail above, according to the present invention, it is possible to provide a bottle portion which has a strong bonding strength between the functional resin and the main resin, is hard to peel off, and is particularly strong against external impact such as dropping.

Further, the present invention has an advantage that the functional resin can be concentratedly distributed to the bottle portion. Therefore, the container body can be stretch blow-molded, and the bottle portion can be obtained at low cost.

Further, according to the present invention, the bottle portion is heated and crystallized,
Compared with the case of two-color molding or insert molding, the process can be simplified and the number of molds required for molding can be reduced.

Furthermore, since the functional resin and the main resin are cooled and solidified in the same mold from the molten and fluid state to the laminated state where they are joined to each other through the same heat and pressure process, dimensional accuracy and dimensional heat stability. The sex is extremely good. (There is little peeling deformation under thermal shock and heat cycle.) Also, only the functional resin is limited to the throttle part and the bottle mouth part, the part corresponding to the bottle body part, and the part corresponding to the bottle body part from the drawing part The transition part of is composed only of the main resin, and the main resin has an intricate interface with an indeterminate interface, so that only the main resin is stretched in the subsequent biaxial stretching blow molding process. Therefore, the stretch blow molding can be performed more smoothly from the transition part to the part corresponding to the bottle body, as compared with the multi-layered parison.

Further, by applying the present invention to a multi-cavity production system in which resin is injected from one injection unit, the resin is branched, and a large number of parison cavities are flowed in, the functional resin of the bottle mouth part, and It is possible to make the constituent parts of the main resin uniform, and to prevent the functional resin from flowing into the part corresponding to the bottle body part, which is caused by the different filling speed due to the cavities.

[Brief description of drawings]

1 is a perspective view of a parison of the present invention, and FIGS. 2 (a) to 2 (d) are schematic views showing various shapes of a bottle neck portion, a throttle portion, and a transition portion of the parison of the present invention, and FIG. Is a cross-sectional view of the parison molding apparatus of the present invention, FIGS. 4 (a) to 4 (d) are cross-sectional views showing the molding process according to the present invention, and FIGS. 5 (a) to 5 (b).
FIG. 6 is a cross-sectional view showing another example of the molding process according to the present invention. 1 …… Parison 1 ′ …… Bottle mouth 2 …… Mouth portion 3 …… Projecting ring portion 4 …… Main resin injection port 5 …… Functional resin injection port 6 …… Part corresponding to bottle body 7 …… Throttle 8 …… Mouth bottom 9 …… Transition 10 …… Core type 11 …… Lip type 12 …… Cavity type 13 …… Main resin injection nozzle 14 …… Functional resin injection nozzle 21 …… Main Resin 22: Functional resin

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B29L 22:00 31:56

Claims (2)

(57) [Claims] 1. A biaxially stretch blow molded bottomed cylindrical parison having a brim-shaped protruding ring portion connected to the lower end of the mouth, and a functional resin gate being provided on the outer peripheral portion of the protruding ring portion. One or more, and a main resin gate at the bottom, and a narrowing part connected between the protruding ring part and the part corresponding to the bottle body through the transition part to the part corresponding to the bottle body. The cross-sectional area of the narrowed portion is smaller than the cross-sectional area of the lower end of the mouth portion and smaller than the cross-sectional area of the portion corresponding to the bottle body, and the mouth portion and the protruding ring portion function. A biaxially stretched blow molding parison having a multi-layered structure of two or more layers of a resin and a main resin, and the portion corresponding to the bottle body and the transition portion are formed of only the main resin. 2. A mouth portion, a collar-shaped projecting ring portion connected to the lower end thereof, and a portion corresponding to the bottle body portion located below the mouth portion, and between the projecting ring portion and the portion corresponding to the bottle body portion. In, there is a throttling portion connected to the portion corresponding to the bottle body through the transition portion, the cross-sectional area of this throttling portion is smaller than the cross-sectional area of the lower end of the mouth portion, and than the cross-sectional area of the portion corresponding to the bottle body portion. Also, using an injection mold with a cavity that corresponds to the shape of the parison set to a small value, from the main resin gate at the position corresponding to the bottom of the parison into the cavity, corresponding to the protrusion of the parison The process of injecting the main resin until the cavity region below the cavity region is filled, and the flow end surface of the main resin reaches the cavity region corresponding to the narrowed portion of the parison, When the rise in the cavity pressure of the parison is detected, the functional resin is injected into the cavity area corresponding to the protruding ring portion from the gate for injecting the functional resin at the position corresponding to the outer periphery of the protruding ring portion of the parison. After the process of injecting in the direction and the injection of the main resin is temporarily stopped or without stopping, the functional resin and the main resin are simultaneously injected, or sequentially or alternately,
At least the main resin portion inserted into the protruding ring portion is formed, the main resin layer is stretched and formed along the core mold wall surface, and the interface between the functional resin and the main resin is indefinite. Molding method of parison.