JP6628512B2 - Container manufacturing method - Google Patents

Description

  The present invention relates to a container manufacturing method for manufacturing a container having a predetermined shape by liquid blow-molding a preform made of a permeable polyester.

  Polyester containers having permeability such as polyethylene terephthalate bottles (pet bottles) and polyethylene naphthalate containers are used for various liquids such as beverages, cosmetics, chemicals, liquid detergents, toiletries such as shampoos, etc. It is used for housing.

  Such a container is generally manufactured by blow molding a preform made of polyester formed in a bottomed cylindrical shape. Further, as blow molding for molding a preform into a container, there is known liquid blow molding in which a pressurized liquid is used instead of pressurized air as a pressurized medium supplied to the preform.

  For example, Patent Literature 1 discloses a method of manufacturing a container having a predetermined shape by supplying a pressurized liquid to a polyethylene terephthalate preform and subjecting the preform to liquid blow molding. In such a method of manufacturing a container using liquid blow molding, a step of filling the container with the content liquid after molding is performed by using a content liquid finally contained in the container as a product to be supplied to the preform. Can be omitted to simplify the manufacturing process and the configuration of the blow molding apparatus.

JP-T-2005-529002

  When manufacturing a container containing an alcohol-containing liquid containing an alcohol such as ethanol as a content liquid, such as a liquid detergent or a softener or an alcoholic beverage, the alcohol-containing liquid is applied to a polyester preform by a pressurized medium. And liquid blow molding is performed.

  However, when an alcohol-containing liquid is supplied to a polyester preform to perform liquid blow molding, the inner surface of the preform is attacked by alcohol during the molding, and fine irregularities are formed on the inner surface of the container after molding. There has been a problem that cloudiness (cloudiness) occurs and the transparency of the container is impaired.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a container manufacturing method capable of manufacturing a permeable polyester container for accommodating an alcohol-containing liquid by liquid blow molding. To provide.

The container manufacturing method of the present invention is a method of manufacturing a container having a predetermined shape by performing liquid blow molding of a transparent or translucent preform capable of visually recognizing a content liquid contained therein from the outside made of polyethylene terephthalate . a in ethanol was supplied to the preform ethanol-containing liquid containing at a ratio of less than 10 wt% as a pressurizing medium by the preform to the liquid blow molding, housing the preform, the inside from the outside The obtained content liquid is formed into a transparent or translucent container that can be visually recognized .

In the method for manufacturing a container according to the present invention, in the above structure, the ethanol- containing liquid preferably contains ethanol at a ratio of 5 wt% or less.

According to the present invention, the preform is supplied to the preform ethanol-containing liquid, which contains ethanol in a proportion of less than 10 wt% as a pressurizing medium since such that the liquid blow-molding, the inside from the outside as a preform Even if the contained liquid made of transparent or translucent polyethylene terephthalate is used, the occurrence of cloudiness is suppressed in the container after molding, and the container containing the ethanol- containing liquid has high transparency. Containers can be manufactured.

As described above, according to the present invention, a container capable of manufacturing a transparent or translucent polyethylene terephthalate container capable of visually recognizing the content liquid contained therein from the outside that contains the ethanol- containing liquid by liquid blow molding. Can be provided.

It is an explanatory view showing the composition of a liquid blow molding device. It is explanatory drawing which shows the state which is performing the liquid blow molding of the preform.

  Hereinafter, the present invention will be described more specifically with reference to the drawings.

  The method for producing a container of the present invention is a method for producing a container having a predetermined shape by subjecting a preform made of a permeable polyester to liquid blow molding to produce a container having a predetermined shape, wherein the alcohol contains alcohol at a ratio of less than 15 wt%. The preform is liquid blow-molded by supplying the contained liquid to the preform as a pressurized medium. According to the method for producing a container of the present invention, even when a preform made of a polyester having permeability is used, it is possible to suppress the occurrence of cloudiness in the molded container and to provide a transparent container for containing the alcohol-containing liquid. A highly reliable container can be manufactured. In the present invention, “having transparency” means that the content liquid contained in the container is visible from the outside, and includes various things such as colorless or colored, transparent or translucent.

  In the method for producing a container of the present invention, for example, a preform made of polyethylene terephthalate (PET) can be used as the preform made of polyester having permeability. In this case, the container can be formed into a so-called PET bottle by forming the preform into a substantially test tube shape having a cylindrical mouth and a bottomed cylindrical body connected to the mouth.

  The preform is not limited to polyethylene terephthalate as long as it is made of a polyester having transparency, and another material such as polyethylene naphthalate (PEN) may be used. Further, as the preform, if the formed container has permeability, it may be a laminated structure in which polyester is used as the innermost layer and a different polyester resin or another resin layer is laminated on the outermost layer. Further, it is also possible to use a plurality of polyester resins, or a polyester resin blended with a resin of another material at a predetermined ratio. Further, the shape of the preform or the container can be variously changed as long as the container capable of containing the content liquid can be manufactured by liquid blow molding the preform.

  In the method for producing a container of the present invention, an alcohol-containing liquid containing alcohol in a proportion of less than 15 wt% is used as a pressurizing medium for liquid blow molding of a preform. That is, in the container manufacturing method of the present invention, as the pressurized medium, an alcohol-containing liquid in which alcohol is mixed with a base liquid such as water at a ratio of less than 15 wt%, that is, a ratio of less than 15% by weight, is used. Used. In addition, the alcohol-containing liquid may be a liquid obtained by further adding other components such as a surfactant, a preservative, a coloring agent, an enzyme, and a fragrance to a base liquid such as water in addition to the alcohol.

  The alcohol-containing liquid may contain alcohol at a ratio of 10 wt% or less. In this case, cloudiness of the container after the liquid blow molding can be more effectively suppressed. Further, the alcohol-containing liquid may contain alcohol at a ratio of 5 wt% or less. In this case, cloudiness of the container after the liquid blow molding can be more effectively suppressed.

  As the alcohol-containing liquid, a liquid containing ethanol (ethyl alcohol) as the alcohol can be used. In this case, the alcohol-containing liquid can be, for example, alcoholic beverages, liquid detergents, detergents or liquid softeners. In addition, a liquid containing alcohol other than ethanol can be used as the alcohol-containing liquid.

  The method for producing a container according to the present invention can be performed using a liquid blow molding apparatus 1 as shown in FIGS. 1 and 2, for example. This liquid blow molding apparatus 1 performs liquid blow molding of a preform PF made of a permeable polyester using an alcohol-containing liquid L containing alcohol at a ratio of less than 15 wt%, so that the alcohol-containing liquid L is contained therein. To manufacture a container C having a predetermined shape in which is stored.

  The liquid blow molding apparatus 1 has a blow mold 11. The blow mold 11 has a cavity 12 having a shape corresponding to the shape of the container C. In the illustrated case, the cavity 12 is formed in a bottle shape and opens upward on the upper surface of the blow mold 11. Although not shown in detail, the blow mold 11 can be opened to the left and right. By opening the blow mold 11, the container C after molding can be taken out of the blow mold 11.

  In the case shown in the figure, a resin material made of polyethylene terephthalate (PET) is used as a preform PF by means of injection molding, compression molding, extrusion molding, or the like to form a cylindrical mouth PFa and a bottomed cylindrical body PFb. What was formed in the substantially test tube provided with is used. The preform PF is placed in the blow mold 11 in a standing posture in which the mouth PFa projects upward from the cavity 12 after being preheated to a predetermined temperature at which the preform PF develops extensibility using a heater (not shown) or the like. .

  A nozzle unit 13 is provided on the upper side of the blow mold 11 so as to be vertically movable relative to the blow mold 11. The nozzle unit 13 has a main body block 14 and a blow nozzle 15.

  The blow nozzle 15 includes a cylindrical nozzle body 15a having a diameter smaller than the inner diameter of the mouth PFa of the preform PF, and a large-diameter holding portion 15b formed integrally with the nozzle body 15a. It is formed integrally with a resin material or the like, and is fixed to the main body block 14 by fitting the holding portion 15b into the inner surface of the main body block 14.

  The nozzle body 15a is disposed coaxially with the cavity 12 of the blow mold 11, and is engaged with the mouth PFa of the preform PF mounted on the blow mold 11 when the nozzle unit 13 is lowered to a predetermined position. It has become. Reference numeral 16 denotes a seal that seals between the nozzle body 15a and the mouth PFa.

  A supply path 17 is provided inside the main body block 14 and extends in the up-down direction coaxially with the nozzle body 15a. The supply path 17 is connected to the blow nozzle 15 at a lower end thereof.

  A pressurized liquid supply unit 19 is connected to the supply path 17 via a pipe 18. The pressurized liquid supply unit 19 can supply the alcohol-containing liquid L pressurized to a predetermined pressure to the supply path 17 via the pipe 18. As described above, the alcohol-containing liquid L contains alcohol at a ratio of less than 15 wt%.

  When the pressurized alcohol-containing liquid L is supplied from the pressurized liquid supply unit 19 to the supply path 17, the alcohol-containing liquid L is supplied from the supply path 17 to the preform placed in the blow mold 11 via the blow nozzle 15. It is supplied inside the PF. Thereby, the preform PF is liquid blow-molded by the alcohol-containing liquid L into a container having a shape along the cavity 12 of the blow mold 11.

  As the pressurized liquid supply unit 19, for example, one having a configuration using a plunger pump as a pressurization source is used.

  Inside the supply path 17, a seal pin 20 for opening and closing the supply path 17 with respect to the blow nozzle 15 is arranged. The seal pin 20 is formed in a columnar shape extending along the axis of the supply path 17, and is vertically movable relative to the main body block 14 inside the supply path 17. On the other hand, a tapered closing surface 15c is provided on the upper surface of the holding portion 15b of the blow nozzle 15. When the seal pin 20 moves to the lower stroke end and the tapered surface 20a provided at the lower end of the seal pin 20 comes into contact with the closing surface 15c, the communication between the supply path 17 and the nozzle body 15a is cut off by the seal pin 20, and the supply is stopped. The path 17 is closed with respect to the blow nozzle 15. On the other hand, when the seal pin 20 moves upward and the tapered surface 20a provided at the lower end of the seal pin 20 is separated from the closing surface 15c, the supply path 17 communicates with the nozzle body 15a. Open state, that is, open state.

  Therefore, as shown in FIG. 2, the pressurized liquid supply unit 19 is engaged with the nozzle body 15a engaged with the opening PFa of the preform PF, the seal pin 20 is opened, and the supply path 17 communicates with the blow nozzle 15. When activated, the pressurized alcohol-containing liquid L is supplied into the preform PF from the pressurized liquid supply unit 19 through the supply path 17 and the blow nozzle 15, and the preform PF can be subjected to liquid blow molding. Then, the container C containing the alcohol-containing liquid L therein is manufactured by the liquid blow molding.

  The liquid blow molding device 1 may have a configuration in which an extension rod 21 is slidably mounted in an insertion hole formed in the center of the seal pin 20. In this case, the extension rod 21 can be moved relatively vertically (axially) with respect to the seal pin 20, and moves downward (to the bottom of the cavity 12) with respect to the seal pin 20, as shown in FIG. By doing so, the bottom part of the trunk PFb of the preform PF arranged in the blow mold 11 is pushed down, and the trunk PFb is extended in the axial direction (vertical direction) inside the cavity 12. In other words, by using the liquid blow molding apparatus 1 having the configuration in which the stretching rod 21 is provided, the preform PF placed in the blow molding die 11 is stretched in the longitudinal direction using the stretching rod 21 while the alcohol is pressed. The container C can be manufactured by biaxial stretch blow molding in which the liquid L is stretched in the radial direction.

  Next, in order to confirm the effects of the container manufacturing method of the present invention, a plurality of polyethylene terephthalate preforms were prepared, and a plurality of types of alcohol-containing liquids having ethanol concentrations different from each other were prepared on these preforms. Was supplied (filled) to perform liquid blow molding, a container containing an alcohol-containing liquid was produced by the liquid blow molding, and the transparency of the produced container was evaluated. For comparison, a container was manufactured by supplying water as a pressurized medium to the same preform made of polyethylene terephthalate as described above and performing liquid blow molding.

  In the above liquid blow molding, the temperature of the preform is heated to 120 ° C. in advance using a heater or the like, the temperature of the alcohol-containing liquid and water supplied to the preform is 25 ° C., and the temperature of the blow mold is 40 ° C. The pressure (blow pressure) of the alcohol-containing liquid and water supplied to the preform was 3.0 MPa.

  In addition, haze (cloudiness) was measured using a device such as a haze meter for each of the front and side surfaces of the upper and lower parts of the body of the molded container, and the haze value at each of these parts was comprehensively considered. Then, the transparency of each container was evaluated as ○ (good) or × (poor). In addition, haze (degree of haze) is an index relating to transparency obtained from the ratio of diffuse transmitted light to total light transmitted light.

  Table 1 shows the evaluation results.

  From the evaluation results shown in Table 1, it is possible to improve the transparency of the manufactured container by making the alcohol-containing liquid supplied to the preform the ethanol concentration, that is, the alcohol concentration less than 15 wt%. I was able to confirm that I could. In particular, when the alcohol-containing liquid supplied to the preform has an ethanol concentration of 10 wt% or less, the transparency of the manufactured container can be improved, and the ethanol concentration can be 5 wt%. %, It was confirmed that the transparency of the manufactured container could be further improved.

  On the other hand, when the ethanol concentration of the alcohol-containing liquid supplied to the preform was 15 wt% or more, the formed container became cloudy and the transparency was poor.

  The present invention is not limited to the above-described embodiment, and it goes without saying that various changes can be made without departing from the scope of the invention.

  For example, in the above embodiment, the preform and the container are made transparent, but the present invention is not limited to this, and the preform and the container may be colored in a predetermined color if they have transparency. Can also. Also in this case, when the alcohol-containing liquid supplied to the preform has an alcohol concentration of less than 15 wt%, the occurrence of cloudiness (cloudiness) due to the formation of fine irregularities on the inner surface of the container. The transparency of the colored container can be ensured by suppressing it.

  Further, the blow molding apparatus for performing the liquid blow molding of the preform PF is not limited to the liquid blow molding apparatus 1 having the configuration shown in FIGS. 1 and 2, but various configurations can be used.

  Further, in the above-described embodiment, the alcohol-containing liquid containing alcohol at a ratio of less than 15 wt% is supplied to the preform as a pressurized medium and the preform is subjected to liquid blow molding. Alternatively, a liquid containing an alkali component or a surfactant in a ratio less than a predetermined weight concentration can be used. In this case, the alkali component and the surfactant contained in the liquid cause cloudiness in the container after the liquid blow molding when the alkali component and the surfactant are contained in a proportion of a predetermined weight concentration or more.

1 Liquid Blow Molding Apparatus 11 Blow Mold 12 Cavity 13 Nozzle Unit 14 Main Block 15 Blow Nozzle 15a Nozzle Body 15b Nipping Part 15c Closed Surface 16 Seal Body 17 Supply Path 18 Pipe 19 Pressurized Liquid Supply Part 20 Seal Pin 20a Tapered Surface 21 Stretch Rod PF Preform PFa Mouth PFb Body L Alcohol-containing liquid C Container

Claims (2)

A container manufacturing method for manufacturing a container having a predetermined shape by performing liquid blow molding of a transparent or translucent preform capable of visually recognizing a content liquid contained therein from the outside made of polyethylene terephthalate ,
An ethanol- containing liquid containing ethanol at a ratio of 10 wt% or less is supplied to the preform as a pressurized medium, and the preform is subjected to liquid blow molding. The method for producing a container, comprising: forming a transparent or translucent container into a transparent or translucent container. The method for producing a container according to claim 1, wherein the ethanol- containing liquid contains ethanol at a ratio of 5 wt% or less.

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