JPH03162928A - Cylindrical opening part of preform and method of molding bottom - Google Patents

Abstract

PURPOSE:To enable the cylindrical opening part and bottom of preform to be molded correctly by molding a multi-layered structure on the cylindrical body and thereafter heating one end and the other end of the cylindrical body and further pressing respectively each mold and cylindrical body in a cylindrical opening female mold and bottom forming female mold in the axial direction of the cylindrical body. CONSTITUTION:One end part 2 of a cylindrical body 1 in the multi-layered structure where layers comprising thermoplastic polyester having ethylene terephthalate as a main repeating unit or polyester are a main body heated and softened is at the temperature of a glass transi tion point or higher and at the temperature of crystallization or lower. The heated and thus softened one end part 2 of the cylindrical body 1 is inserted into a cylindrical opening female mold 10 provided with molding resessions 11 such as screws, flanges, and the like in its inner surface and formed as a split mold and in the cylindrical body 1, a cylindrical opening female mold 12 is inserted and then the other end part 3 of the cylindrical body 1 is pressed by means of a cylindrical body pressing tool 13 in the axial direction of the cylindrical body 1. Thereby, at the outside of the one end part 2, screws, flanges, and the like formed on the cylindrical opening mold 10 are molded correctly and at the inside of the one end part 2, a cylindrical opening part 30 formed according to the outer surface of top end of the cylindrical opening female mold 12 is molded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] -2 Is the present invention a method of molding a preform for bottle molding? Regarding leaving.

[Traditional technique]

Conventionally, a single polyethylene terephthalate preform or the like has generally been molded using an extrusion molding tool.

As a preform molding method for a multilayered bottle with gas barrier properties, etc., a pipe made of multiple resin layers is molded by extrusion molding, etc., and then one end of this pipe is attached with a screw, A method of forming a preform has been adopted in which a flange or the like is formed to form a mouth part, and the other end of the vibrator is closed to form a bottom part.

The molding of the mouth part of this preform is generally carried out as follows:
One end of the heated and softened pipe is blow-molded by pressurizing it with high-pressure air in a mold with recesses for forming threads, flanges, etc.

The bottom of this preform is generally formed by sandwiching and pressing the other end of the heated and softened pipe between a concave mold and a convex mold, and pressing the other end of the pipe inside the cavity. Compression molding is used to form the part into a closed bottom part such as a hemispherical shape.

[Problem to be solved by the invention]

In the conventional method of forming the mouth part of the preform, it is difficult to accurately make the screw or flange protrude outside, and there is an annular shape inside the protruding part of the screw or flange. A concave portion was formed, and this concave portion was sometimes buckled by the pressing force during capping.

In addition, since the conventional method of molding the bottom of the preform is a compression molding method, the wall thickness may become thick or thin, making it impossible to mold to the exact dimensions, and in order to avoid this problem, excess resin is required. } If the material was to be removed, an additional process would be required to remove it after molding.

Furthermore, when the bottom part is molded into a hemispherical shape or the like, radial wrinkles occur on the bottom part, and these wrinkles remain even after the bottle is molded and are unsightly.

The present invention is based on the above points, and has the following features: 4. It is possible to mold a preform with an accurate mouth part and no dents on the inside thereof, and the preform can be molded without excess resin wetting out. A technical problem is to be able to mold an accurate bottom part and to mold the bottom part of a preform into a bottom part that does not generate wrinkles.

[Means to solve the problem]

The invention according to claim 1 provides that the one end portion 2 of the cylindrical body 1 having a multilayer structure mainly made of a thermoplastic polyester having ethylene terephthalate as a main repeating unit, or a layer made of the polyester, is heated to a temperature higher than the glass transition point temperature. heated to a temperature below the crystallization temperature,
The heated one end giPJ2 of this cylindrical body 1 is twisted on the inner surface, a recess 11 for forming a flange, etc. is provided, and the cylindrical body 1 is inserted into a female mold 10 for a mouth cylinder formed as a split mold. The male mold 12 for the mouth tube part is inserted into the cylinder body 1, and then the other end 3 of the cylinder body 1 is pressed in the axial direction of the cylinder body 1 with the cylinder body pressing tool 13 to press the cylinder body 1. A method for forming a mouth barrel part of a renovated projector was adopted in which a mouth barrel part 30 formed with a flange or the like is formed on one end part 2.

The invention according to claim 2 provides the following steps: The female mold 10 for the mouth barrel is heated to a temperature higher than the crystallization temperature and lower than the melting point of the thermoplastic polyester whose main repeating unit is ethylene terephthalate, and the male mold 12 for the mouth barrel is heated. One end 2 is kept at a temperature below the crystallization temperature of the thermoplastic polyester whose main repeating unit is ethylene terephthalate.
The method for molding a mouth barrel portion of a preform according to claim 1, wherein the mouth barrel portion 30 is formed by molding the preform into the mouth barrel portion 30.

The invention according to claim 3 is made of thermoplastic polyester whose main repeating unit is ethylene terephthalate, or
The other end 3 of the cylindrical body 1 having a multilayered structure, in which the layer made of polyester is the main body, is heated to a temperature above the glass transition point and below the crystallization temperature, and only the tip is heated above the melting temperature. The heated other end 3 of the cylindrical body 1 is inserted into the bottom female mold 2.
At the same time, the bottom male mold 2 is inserted into the cylinder body 1.
2 is inserted, and with a distance maintained between the tip of the male bottom mold 22 and the inner bottom surface of the female bottom mold 20, the opening part 30 of the cylinder 1 is inserted into the cylinder. With the pressing tool 13, the cylindrical body 1
Press the other end 3 of the cylinder 1 in the axial direction of the bottom gPJ31.
This method was used to form the bottom part of the preform.

[For production]

The invention according to claim 1 is made of thermoplastic polyester whose main repeating unit is ethylene terephthalate, or
The layer made of polyester heats one end 2 of the cylinder 1 having a main multilayer structure to a glass transition temperature (approximately 70°C).
The cylinder body 1 is heated and softened at a temperature below the crystallization temperature (approximately 170°C) in the above manner, and the one end portion 2 of the heated and softened cylinder body 1 is
The inner surface is provided with a recess 11 for molding screws, flanges, etc., and is inserted into a female mold 10 for a mouth cylinder formed as a split mold, and a male mold 12 for a mouth cylinder is inserted into this cylinder 1. Insert the cylinder 1, and press the other end 3 of the cylinder 1 with the cylinder pressing tool 13.
When pressed in the axial direction, the cylindrical body 1 is softened, and the one end 2 is pushed into the recess 11 of the sealed female mold 10 for the mouth barrel part.
On the outside of the one end part 2, screws, flanges, etc. formed in the female mold 10 for the mouth barrel part are accurately molded, and on the inside of the one end part 2, the male mold 12 for the mouth barrel part is formed. Mouth barrel part 30 shaped according to the outer surface of the tip part
is formed.

The invention according to claim 2 is the mouth barrel part 3 of the invention according to claim 1.
During molding, the female mold 1o for the mouth tube part is heated to a temperature above the crystallization temperature and below the melting point (approximately 170°C to about 260'C') of thermoplastic polyester whose main repeating unit is ethylene terephthalate. The mouth barrel part 30 is formed by heating and keeping the male mold 12 for the mouth barrel part at a temperature below the crystallization temperature (approximately 170° C.) of a thermoplastic polyester whose main repeating unit is ethylene terephthalate. Therefore, the mouth part 3
The outside of o is completely crystalline, and the inside is amorphous.

The invention according to claim 3 is made of thermoplastic polyester whose main repeating unit is ethylene terephthalate, or
The layer made of polyester heats the other end gPJ3 of the cylindrical body 1 having a multilayer structure, which is the main body, at a glass transition temperature (70°C).
) and above to a temperature below the crystallization temperature (approximately 170'C) to soften it, and only the tip portion is heated to a temperature above the melting point (approximately 260'C) to melt it, and this heated cylinder 1 The other end 3 is inserted into the female bottom mold 20, and a space is maintained between the tip of the male bottom mold 22 and the inner bottom surface of the female bottom mold 20 inside the cylinder 1. When the mouth part 30 of the cylinder 1 is pressed in the axial direction of the cylinder 1 with the cylinder pressing tool 13 in the hanging state, the heated other end 3 of the cylinder 1 is pressed against the bottom female mold 20. It is pushed into the gap between the inner bottom surface of the mold 22 and the tip of the male bottom mold 22, and the gap is filled, forming the bottom part 31 with an accurate shape.

The thermoplastic polyester having ethylene terephthalate as a main repeating unit in the present invention usually has an acid component of 80 mol% or more, preferably 90 mol% or more of terephthalic acid, and a glycol component of 80 mol%, preferably 90 mol%. The above refers to a polyester which is ethylene glycol, and the remaining acid components include isophthalic acid, cyphenyl ether 4,4'-dicarboxylic acid, naphthalene 14 or 2,6-dicarboxylic acid, adipic acid, sebacic acid,
Decane 1,10-dicarboxylic acid, hexahydride terephthalic acid, and other glycol components -9- such as propylene glycol, 1,4-butanesiol, neobentyl glycol, diethylene glycol, 1
, 6-hexylene glycol, cyclohexanedimethanol, 2,2-bis(4-hydroxyphenyl)broban, 2,2-bis(4-hydroxyethoxyphenyl)
propane, or P-oxybenzoic acid as the oxyacid;
It means a polyester containing P-hydroxybenzoic acid or the like.

The polyester in the present invention may contain additives such as colorants, ultraviolet absorbers, antistatic agents, thermal oxidative deterioration inhibitors, antibacterial agents, and lubricants in appropriate proportions, if necessary.

The thermoplastic polyester of the present invention needs to have an intrinsic viscosity of 0.55 or more, preferably 0.55 or more. It has an intrinsic viscosity of 6 or more, more preferably 0.7 to 1.4. Intrinsic viscosity is a solution of polyester dissolved in a mixed solvent of phenol/tetrachloroethane (674 weight ratio).
Intrinsic viscosity measured at 0°C. Intrinsic viscosity is 0
．． If it is less than 55-101, it will be difficult to obtain a transparent, non-quality molded product during parison molding, and the mechanical strength will also be insufficient.

〔Example〕

1 to 9 are explanatory diagrams of embodiments of the invention according to claims 1 to 3, and the cylinder 1 used in the embodiment of the invention according to claim 1 is formed into five layers by extrusion molding. The first innermost layer is polyethylene terephthalate, the second layer is an adhesive layer made of adhesive polyolefin, and the third layer is an ethylene vinyl acetate copolymer. The fourth layer is the same adhesive layer as the second layer, and the outermost fifth layer is the same polyethylene terephthalate layer as the innermost first layer.

This cylinder 1 has an inner diameter of 19 mm and an outer diameter of 25 mm.
, the length is 106 mm.

One end 2 of this cylinder 1 is inserted into the annular recess of the one end heating device 7 shown in FIG. The heating temperature in step 2 is above the glass transition point temperature (about 70'C) of polyethylene terephthalate and below the crystallization temperature (about 170'C), preferably about 90°C or above and about 150°C. Heat to a temperature below °C.

Furthermore, what is important here is the amount of the heated portion of the one end portion 2, and the amount of this heated portion is determined when the mouth tube portion is inserted into the female mold 10 for the mouth tube portion in the next step. female mold 10
Roughly speaking, the amount required to fill this void is the amount of screws, flanges, etc. formed in the female mold 10 for the mouth part. The amount varies depending on the size, but in any case, it is best to use an amount slightly larger than the amount of voids.

Next, the one end portion 2 heated as described above is placed in a female mold 10 for a mouth tube portion formed as a split mold and having four portions 11 for forming screws and flanges on the inner surface as shown in FIG. At the same time, the male mold 12 for a mouth tube portion formed in a cylindrical shape is inserted into the cylinder 1 so that its tip is in contact with the bottom surface of the female mold 10 for a mouth tube portion.

=12= Next
At step 3, the cylindrical body 1 is firmly pressed in the axial direction toward the female mold 10 for the mouth part 30 of the preform having screws and flanges as shown in FIGS. 4 and 5. was molded.

The embodiment of the invention set forth in claim 2 heats one end portion 2 of the cylindrical body 1 in the same manner as the embodiment of the invention set forth in claim 1,
At the same time, the female mold 10 for the mouth part is heated to a temperature above the crystallization temperature of polyethylene terephthalate and below the melting point (about 170° C. to about 260° C., preferably about 200° C.
℃ to about 250 degrees Celsius, and the male mold 12 for the neck part is maintained at a temperature below the crystallization temperature of polyethylene terephthalate (about 170 degrees Celsius), and The mouth barrel portion 30 of the preform was molded in the same manner as in Example 1 of the invention.

An embodiment of the invention as claimed in claim 3 is a cylinder 1 formed by the embodiment of the invention as claimed in claim 1 and shown in FIG.
The other end 3 is inserted into the annular recess of the other end heating device 17 shown in FIG.

The possible heating temperature range of the other end 3 is the one end i? of the cylinder 1 in the above embodiment. The heating temperature range is the same as that of 132, but since the tip of the other end 3 is fused to form the bottom 31, in this embodiment, the other end 3 is
The temperature at the tip of the tube was set at 270°C, which is about 260°C or higher.

The important thing here is that the amount of heating at the other end 3 is
This is the same as the molding of the mouth barrel portion 30 described above, and the amount of the heated portion of the other end portion 3 is such that when inserted into the female bottom mold 20 in the next step, the female mold 20 for the bottom and the bottom portion are heated. This is the amount necessary to fill the void left between the male molds 22,
Furthermore, the amount required to fill this void is
The amount varies depending on the shape of the spacer 1, ie, hemispherical, elliptical, flat-bottomed, etc., but it is best to use an amount slightly larger than the amount of voids.

Next, the heated other end 3 of the cylindrical body 1 is inserted into a female mold 20 for the bottom, which has a hemispherical inner bottom and is formed as a split mold, as shown in FIG. Insert the bottom male mold 22 into the cylindrical body 1 together with the
The tip of the male bottom mold 22 is opened to the inner bottom surface of the female bottom mold 20 to form the bottom 31 of the preform. Mouth part 3
The end face of the cylindrical body 1 was pressed in the axial direction of the cylindrical body 1 toward the bottom female mold 20 using the cylindrical body pressing tool 13 to mold a preform having a hemispherical bottom part 31.

The outer diameter of the threaded part of the mouth barrel part 30 of the molded preform is 28 mm, the wall thickness of the bottom MJ31 is 3 mm, and the total length is 100 mm.
This is for ml bottles.

Moreover, FIG. 10 shows a preform molded in another embodiment, in which the bottom part 31 is the same as that in FIG. 9, but only a flange is molded in the mouth barrel part 30. be.

The cylinder body 1 is pressed in the axial direction by the cylinder body pressing tool 13.
This may be carried out by stopping the opening and pressing down the female mold 10 for the mouth and the female mold 20 for the bottom.

〔Effect of the invention〕

15 The present invention involves forming a cylinder 1 with a multilayer structure mainly made of a thermoplastic polyester having ethylene terephthalate as a main repeating unit or a layer made of the polyester, and then forming a cylinder 1 with one end 2 and a layer made of the polyester. heating the other end 3;
In the female mold 10 for the mouth part and in the female mold 20 for the bottom part,
Pressing the respective molds and the cylinder 1 in the axial direction of the cylinder 1, the mouth cylinder part 30 of the preform, and
The bottom part 31 is zeta-shaped so that the bottom part 31 can be formed accurately, and even if the preform has multiple layers, the mouth part 30 and the bottom part 31 can be molded without greatly disturbing each layer of the multilayer preform. No annular recess is generated in the giPJ 30, no wrinkles are generated on the bottom 31, and excess resin can be prevented from wetting out during rough molding.

In addition, the invention as claimed in claim 2, in molding the mouth barrel portion 30, simultaneously performs a thermal crystallization (whitening) step for improving the heat resistance of the k-mouth barrel portion 30, which has conventionally been carried out in a separate process. Instead of using a sophisticated scale that can be used for this purpose, instead of forming a whole crystal 16 crystal like the conventional one that crystallizes the mouth part 30, the outside of the mouth part 30 becomes antagonistic and the inside becomes amorphous. We were able to improve the impact resistance and heat resistance.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIGS. 1 to 9 are explanatory views of an embodiment of the invention according to claims 1 to 3, and FIG. 1 is a view showing a cylindrical body;
Fig. 2 shows the process of heating one end, Figs. 3 and 4 show the process of forming the one end into a mouthpiece, and Fig. 5 shows the cylindrical body with the mouthpiece formed. 6 is a diagram showing the heating process of the other end, FIGS. 7 to 8 are diagrams showing the process of molding the other end to the bottom, and FIG. 9 is a diagram showing the molded preform. FIG. 10 is a diagram showing nine preforms molded according to another embodiment 1. DESCRIPTION OF SYMBOLS 1... Cylindrical body, 3... Other end part, 11... Recessed part, 13... Cylindrical body presser, 22... Male mold for bottom part, 2... One end part, 10...・Female mold for mouth tube portion, 12...Male mold for mouth tube portion, 20...Female mold for bottom portion, 30... Mouth tube portion, 17-31...Bottom. 18 Figure 7 Figure 8 Figure 9

Claims (3)

[Claims] (1) One end portion 2 of the cylindrical body 1 made of thermoplastic polyester whose main repeating unit is ethylene terephthalate, or having a multilayer structure mainly consisting of a layer made of the polyester.
is heated to a temperature above the glass transition point and below the crystallization temperature, and the heated one end 2 of the cylindrical body 1 is provided with a recess 11 for forming screws, flanges, etc. on the inner surface, and is used as a split mold. At the same time, the male mold 12 for the mouth barrel is inserted into the cylinder 1, and then the other end 3 of the cylinder 1 is pressed into the cylinder. A method for forming a mouth barrel part of a preform, in which a mouth barrel part 30 having a thread, a flange, etc., is formed on one end part 2 of the cylinder body 1 by pressing the barrel body 1 in the axial direction with a tool 13. (2) The female mold 10 for the mouth part is heated to a temperature above the crystallization temperature and below the melting point of thermoplastic polyester whose main repeating unit is ethylene terephthalate, and the male mold 12 for the mouth part is heated to a temperature above the crystallization temperature and below the melting point temperature.
2. The method for molding a neck part of a preform according to claim 1, wherein the one end part 2 is molded into the neck part 30 while maintaining the temperature at a temperature below the crystallization temperature of the thermoplastic polyester having ethylene terephthalate as a main repeating unit. (3) The other end 3 of the cylindrical body 1 is made of thermoplastic polyester whose main repeating unit is ethylene terephthalate, or has a multilayer structure mainly consisting of a layer made of the polyester.
is heated to a temperature above the glass transition point and below the crystallization temperature, and only the tip is heated to the melting temperature, and the heated other end 3 of the cylinder 1 is inserted into the female mold 20 for the bottom. At the same time, the male bottom mold 22 is inserted into the cylindrical body 1, and with a distance maintained between the tip of the male bottom mold 22 and the inner bottom surface of the female bottom mold 20, Press the mouth part 30 of the cylinder 1 in the axial direction of the cylinder 1 with the cylinder pressing tool 13 to release the cylinder 1.
A method for forming the bottom of a preform in which the other end 3 is formed into the bottom 31.