Patent Description:
It is requested that containers that accommodate cosmetics, milky lotion, or the like have the visually attractive appearance of the containers themselves, in order to enhance the buying intention of consumers. As this type of containers that accommodate cosmetics or the like, a bottle that is made of glass, creates luxurious feeling or massive feeling, and can maintain a beautiful state in repetitive use has been preferably used. In addition, in order to improve the esthetic appearance of containers, it is desired that a vertical-striped pattern be applied to containers that accommodate cosmetics or the like, by performing internal coloring.

Meanwhile, bottles made of glass are heavy and fragile, and also have a high transportation cost or manufacturing cost. Therefore, it has been considered that as containers that accommodate cosmetics or the like, a bottle made of glass is replaced with a resin container.

As one example of a manufacturing method of a resin container, a hot parison blow-molding method is conventionally known. In the hot parison blow-molding method, a resin container is blow-molded by using residual heat at the time of injection molding of a preform. Therefore, there is an advantage in which a variety of resin containers that have excellent esthetic appearance can be manufactured in comparison with a cold parison method.

For example, Patent Literatures <NUM> to <NUM> disclose a configuration in which a gas barrier resin having a longitudinal belt shape is disposed in parallel in a circumferential direction as an intermediate layer of a PET resin container in order to improve a gas barrier property of the container. In this technology of Patent Literature <NUM>, two types of resin are merged in a multiple nozzle, a cavity of a mold is filled with the two types of resin, and a laminated preform is molded.

<CIT>
describes an injection stretch blow molding method that sequentially circulates a plurality of neck mold moving units for supporting and conveying neck molds adapted to hold the neck portions of hollow containers and preforms used to mold the hollow containers at least through preform injection molding, blow molding and ejecting stations, the preform injection molding step, the blow molding step for blow molding the hollow containers from the preforms having their potential heat provided by the injection molding step and the product ejecting step being repeatedly carried out. The injection molding stations of M in number are provided for blow molding stations of N in number (M>N>/=<NUM>). Preforms are injection molded in each of the injection molding stations at an injection molding start time staggered from those of the other injection molding stations by time equal to NxT/M where T is an injection molding cycle time in each of the injection molding stations. The neck mold moving units are sequentially moved from the injection molding stations to the empty blow molding station after the respective one of the injection molding stations has molded the preforms. The preforms are blow molded into the hollow containers in the blow molding stations through their blow molding cycle time which is set within NxT/M. <CIT> describes a thin-wall multilayer preform comprising an inner layer constituted of a first material and symmetric variable thickness zone, and a second external layer molded on a first layer and constituted of a second material. <CIT> describes formation of an optical design pattern in an article of polyethylene terephthalate by utilizing the property of polyethylene terephthalate to become crystallized and whitened upon slow cooling and the fact that cooling of a plastic article molded within a mold advances from the surface portion of the article in contact with the surface of the mold toward the wall of the article. Based on this theory, a desired portion of the wall of an article of polyethylene terephthalate is whitened by properly controlling the degree and speed of cooling of the polyethylene terephthalate article in the mold to cool it slowly. The whitened portion in the wall is developed as an optical design pattern that can be viewed from outside. The whitened optical design pattern developed by the aforesaid technique can be made more distinct by heat treatment and stretching treatment. <CIT> describes an injection molding machine that has a plurality of blockade vertical rib pieces, which partition a middle channel in the peripheral direction into a plurality of channels, parallelly arranged in a range from a prescribed position of the annular middle channel forming an intermediate layer to a junction, in a multiple nozzle part in which a plurality of molten resins are piled up. Using the injection molding machine, over a prescribed height region, the intermediate layer is piled up between substrate layers, a longitudinal connection strip part with the substrate layers connected without the intermediate layer is parallelly extended/formed along the central axis direction, in the peripheral direction, and a preform is molded with the intermediate layer partitioned in the peripheral direction by the longitudinal connection strip part. <CIT> describes various embodiments of a process for making hollow thermoplastic articles. In one embodiment, a process for producing hollow thermoplastic article includes placing a sock preform of a first polymer composition about a core pin and injection molding a molten parison of a second polymer composition that is different than the first polymer composition into an injection mold cavity and onto the sock perform. The injection molding process produces an injection preform having two different material compositions. The process further include blow molding the injection preform to produce a hollow thermoplastic article having an interior surface of the first polymer composition and an exterior surface of the second polymer composition.

Meanwhile, in the technologies of Patent Literatures <NUM> to <NUM>, in practice, it is very difficult to simultaneously inject plural types of resin and precisely control a width, a position, and a shape of an intermediate layer. In addition, a configuration of an injection molding apparatus is complicated and expensive. Therefore, the technology of Patent Literature <NUM> is not necessarily suitable for the purpose of stably forming a vertical-striped color pattern in a container after blow-molding, by performing internal coloring.

Accordingly, the present invention has been made in view of such a problem, and it is an object of the present invention to provide a manufacturing method that enables a vertical-striped color pattern to be stably formed in a container after blow-molding, by performing internal coloring.

A manufacturing method of a resin container in one aspect of the present invention includes: a first injection molding process for injection-molding a first layer of a preform by using a first resin material, the preform having a bottomed cylindrical shape and including a groove that extends in an axis direction; a second injection molding process for injecting a second resin material into the groove of the first layer, the second resin material having a color that is different from a color of the first resin material, and laminating a second layer on an outer peripheral side or an inner peripheral side of the first layer; and a blow-molding process for blow-molding a preform that includes multiple layers and has been obtained in the second injection molding process in a state where residual heat at a time of injection molding is contained, and manufacturing the resin container having a vertical-striped color pattern formed by using the second layer.

In one aspect of the present invention, a vertical-striped color pattern can be stably formed in a container after blow-molding, by performing internal coloring.

Embodiments of the present invention are described below with reference to the drawings.

In the embodiments, in order to make description easily understandable, description is provided in a state where a structure or elements other than a principal portion of the present invention are simplified or omitted. In addition, in the drawings, the same element is denoted by the same reference sign. Note that a shape, a size, or the like of each element in the drawings is schematically illustrated, and does not indicate an actual shape, size, or the like.

First, configuration examples of a preform having a multilayer structure according to the present embodiment are described with reference to <FIG>.

<FIG> is a vertical sectional view of a preform <NUM> in a first example of the present embodiment, and <FIG> is a sectional view taken along line Ib-Ib of <FIG> is a vertical sectional view of a preform <NUM> in a second example of the present embodiment, and <FIG> is a sectional view taken along line Id-Id of <FIG>.

Both the entire shapes of the preforms <NUM> in the first example and the second example illustrated in <FIG> are a bottomed cylindrical shape in which one end side is open and another end side is closed. These preforms <NUM> include a first layer that includes a barrel <NUM> that has been formed in a cylindrical shape, a bottom <NUM> that closes the other end side of the barrel <NUM>, and a neck <NUM> that has been formed in an opening on the one side of the barrel <NUM>. In addition, these preforms have a multilayer structure in which a second layer <NUM> has been laminated on a first layer <NUM>. The first layer <NUM> and the second layer <NUM> that have been described above are formed by performing two stages of injection molding, as described later.

As illustrated in <FIG>, in the preform <NUM> in the first example, a plurality of grooves 11a that each extends along an axis direction has been formed on an outer peripheral side of the first layer <NUM>. The grooves 11a of the first layer <NUM> are disposed at equal intervals in a circumferential direction, and therefore a transverse cross section of the first layer <NUM> illustrated in <FIG> forms an external gear shape. Then, in each of the grooves 11a on the outer peripheral side of the first layer <NUM>, the second layer <NUM> has been formed in such a way that a space of each of the grooves 11a is filled.

In contrast, as illustrated in <FIG>, in the preform <NUM> in the second example, a plurality of grooves 11b that each extends along the axis direction has been formed on an inner peripheral side of the first layer <NUM>. The grooves 11b of the first layer <NUM> are disposed at equal intervals in the circumferential direction, and therefore a transverse cross section of the first layer illustrated in <FIG> forms an internal gear shape. Then, in each of the grooves 11b on the inner peripheral side of the first layer <NUM>, the second layer <NUM> has been formed in such a way that a space of each of the grooves 11b is filled. In addition, as illustrated in <FIG>, in the preform <NUM> in the second example, a hole <NUM> has been formed in a center of a bottom of the first layer <NUM>, and the hole <NUM> of the first layer <NUM> is closed from an inside by the second layer <NUM>.

Note that the specifications, such as a shape or a size, of the first layer <NUM> and the second layer <NUM> are appropriately adjusted according to a shape of a container to be manufactured, a color pattern to be formed in the container, or the like.

Hereinafter, a resin material that is used to form the first layer <NUM> is also referred to as a first resin material, and a resin material that is used to form the second layer <NUM> is also referred to as a second material.

Both the first resin material and the second resin material are a thermoplastic synthetic resin, and can be appropriately selected according to the specifications of a container. Specific examples of a type of material include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycyclohexanedimethylene terephthalate (PCTA), Tritan (registered trademark) (copolyester from Eastman Chemical Company), polypropylene (PP), polyethylene (PE), polycarbonate (PC), polyethersulfone (PES), polyphenylsulfone (PPSU), polystyrene (PS), cyclic olefin polymer (COP/COC), polymethyl methacrylate (PMMA: acryl), polylactic acid (PLA), nylon, and the like. An additive such as colorant can be appropriately added to these resin materials.

In addition, in each of the preforms <NUM> described above, resin materials that are different in color are employed in the first layer <NUM> and the second layer <NUM>. For example, the first resin material and the second resin material are different in an amount of colorant (a shade of color) or a type of colorant (a type of color). Colorant does not need to be added to one of the first resin material and the second resin material.

In addition, both or at least one of the first layer <NUM> and the second layer <NUM>, for example, a layer including a portion that faces an outer periphery, may have a property that allows light to pass through (a light transmissive property). Note that a layer having the light transmissive property may be colored. The present embodiment is described under the assumption that the first resin material is transparent (has the light transmissive property).

In addition, a combination of the first resin material and the second material can be appropriately set according to the specifications of a container, and it is preferable that materials having high mutual weldability be combined. As an example, the first resin material and the second resin material may be resin materials that have different compositions of colorant and are of the same type (for example, PETs).

Next, configuration examples of a resin container (hereinafter also simply referred to as a container) according to the present embodiment are described with reference to <FIG>.

<FIG> is a diagram illustrating an example of a container <NUM> obtained by blow-molding the preform <NUM> in the first example, and <FIG> is a sectional view taken along line IIb-IIb of <FIG> is a diagram illustrating an example of a container <NUM> obtained by blow-molding the preform <NUM> in the second example, and <FIG> is a sectional view taken along line IId-IId of <FIG>. In each of <FIG>, a right half portion of the drawing illustrates the appearance of the container <NUM>, and a left half portion of the drawing illustrates a vertical cross section of the container <NUM>.

In the containers <NUM> illustrated in <FIG>, for example, toner, milky lotion, or the like is accommodated. The container <NUM> includes a neck <NUM> that includes an opening at an upper end, a barrel <NUM> that continuously extends from the neck <NUM> and has a cylindrical shape, and a bottom <NUM> that continuously extends from the barrel <NUM>.

In each of the barrels <NUM> of these containers <NUM>, a color pattern that extends along the axis direction has been formed in a striped shape in the circumferential direction. By applying decoration having such a pattern, the esthetic appearance of the container <NUM> is improved, and the buying intention of consumers can be further enhanced in the use as a cosmetic container or the like.

The color pattern of the container <NUM> according to the present embodiment is formed according to a thickness distribution of the first layer <NUM> and the second layer <NUM>.

In the circumferential direction of the container <NUM>, a portion other than the grooves 11a and 11b of the first layer <NUM> (a portion of ridges 11c and 11d) has been formed to roughly only include the first layer <NUM> (to have a higher ratio of the first layer <NUM>), and therefore the color of the first layer <NUM> appears.

On the other hand, in the circumferential direction of the container <NUM>, the second layer <NUM> has been laminated in a portion of each of the grooves 11a and 11b of the first layer <NUM>. Therefore, in the portion of the grooves 11a and 11b of the first layer <NUM>, the color of the second layer <NUM> that is located in an outer periphery appears in the case of <FIG>, or the color of the second layer <NUM> on an inner layer side appears through the first layer <NUM> in the case of in <FIG>.

Note that the barrel <NUM> of the container <NUM> may be formed to have a thickness that is much smaller than the thickness of the bottom <NUM>, and the barrel <NUM> may have a uniform thickness distribution. If the container <NUM> is formed to have a shape having the thickness distribution described above, luxurious feeling or massive feeling is emphasized, and the container <NUM> can be made closer to a consumer's impression of a cosmetic container.

<FIG> is a diagram schematically illustrating a configuration of a blow-molding apparatus according to the present embodiment. A blow-molding apparatus <NUM> according to the present embodiment is an example of a container manufacturing apparatus, and employs a hot parison method (also referred to as a one-stage method) for blow-molding the container <NUM> by utilizing residual heat (a quantity of internal heat) at the time of injection molding without cooling down the preform <NUM> to room temperature.

The blow-molding apparatus <NUM> includes a first injection molding unit <NUM>, a second includes molding unit <NUM>, a temperature adjusting unit <NUM>, a blow-molding unit <NUM>, a taking out unit <NUM>, and a conveyance mechanism <NUM>. The first injection molding unit <NUM>, the second injection molding unit <NUM>, the temperature adjusting unit <NUM>, the blow-molding unit <NUM>, and the taking out unit <NUM> are disposed in positions that have been displaced in a rotating manner by every predetermined angle (for example, every <NUM> degrees) with the conveyance mechanism <NUM> as a center.

The conveyance mechanism <NUM> includes a transfer plate (not illustrated in <FIG>) that rotates about an axis in a sheet vertical direction in <FIG> as a center. On the transfer plate, a neck mold 36a (not illustrated in <FIG>) that holds the neck <NUM> of the preform <NUM> (or the neck <NUM> of the container <NUM>) is disposed. In a case where the transfer plate includes a single roughly disk-shaped member, one or more neck molds 36a are disposed at every predetermined angle. In a case where the transfer plate includes roughly fan-shaped members that have been divided for respective molding units, one or more neck molds 36a are disposed for each of the divided transfer plates.

The conveyance mechanism <NUM> rotates the transfer plate, and therefore the conveyance mechanism <NUM> conveys the preform <NUM> (or the container <NUM>) in which a neck is held by the neck mold 36a to the first injection molding unit <NUM>, the second injection molding unit <NUM>, the temperature adjusting unit <NUM>, the blow-molding unit <NUM>, and the taking out unit <NUM> in this order. Accordingly, each of the neck molds 36a is shared by a plurality of molding stations (at least the first injection molding unit <NUM> and the second injection molding unit <NUM>). In addition, a tapered part 36a1 has been formed on an outside face (or an inside face) of the neck mold 36a. The tapered part 36a1 comes into contact with or is fitted into a mold of each of the molding stations, and therefore a relative positional relationship between both parts at the time of molding can be regulated. Note that the conveyance mechanism <NUM> can also elevate or lower the transfer plate, and also performs an operation relating to mold closing or mold opening (mold releasing) in the first injection molding unit <NUM> or the second injection molding unit <NUM>.

The first injection molding unit <NUM> includes a mold for first injection molding that includes a cavity mold <NUM>, a core mold <NUM>, and a hot runner mold <NUM>, and manufactures the first layer <NUM> of the preform <NUM>. The first injection molding unit <NUM> is connected to a first injection device <NUM> that supplies the first resin material to the hot runner mold <NUM>. The cavity mold <NUM> includes a fitting part (a concavo-convex part for fitting and a position regulation part) 40b on a face on an opposite side of a face that faces the hot runner mold <NUM> (see <FIG> and <FIG>). The fitting part 40b includes a tapered part 40b1 having a shape that is roughly similar to a shape of the tapered part 36a1 of the neck mold 36a, and receives the tapered part 36a1 of the neck mold 36a by using the tapered part 40b1.

<FIG> illustrates a first injection molding unit 31a that molds the first layer <NUM> of the preform <NUM> in the first example (<FIG>). <FIG> illustrate a first injection molding unit 31b that molds the first layer <NUM> of the preform <NUM> in the second example (<FIG>). Note that herein, when the first injection molding units 31a and 31b do not need to be distinguished from each other, the first injection molding unit <NUM> is used as a generic term.

As illustrated in <FIG> and <FIG>, in the first injection molding unit <NUM>, mold closing is performed on the cavity mold <NUM>, the core mold <NUM>, and the neck mold 36a of the conveyance mechanism <NUM> that have been described above, and a mold space (a molding space) of the first layer <NUM> is formed.

The cavity mold <NUM> illustrated in <FIG> specifies an outer peripheral shape of an inner layer (the first layer <NUM>) of the preform <NUM>. The core mold <NUM> illustrated in <FIG> is inserted into the cavity mold <NUM>, and specifies an inner peripheral shape of the inner layer.

On the other hand, the cavity mold <NUM> illustrated in <FIG> specifies an outer peripheral shape of an outer layer (the first layer <NUM>) of the preform <NUM>. The core mold <NUM> illustrated in <FIG> is inserted into the cavity mold <NUM>, and specifies an inner peripheral shape of the outer layer.

Then, the first resin material is poured into the mold space described above through the hot runner mold <NUM> from the first injection device <NUM>, and therefore the first layer <NUM> of the preform <NUM> is manufactured in the first injection molding unit <NUM>.

Here, on an inner face of the cavity mold <NUM> of the first injection molding unit 31a, protrusions 40a that extend along the axis direction are formed at equal intervals in the circumferential direction, and the inner face of the cavity mold <NUM> forms an internal gear shape, but this is not illustrated. Each of the protrusions 40a of this cavity mold <NUM> has a shape that corresponds to the groove 11a of the first layer <NUM>, and by using the cavity mold <NUM> described above, the grooves 11a and the ridges (narrow and long protrusions) 11c that each extend in the axis direction are formed in an outer periphery of the first layer <NUM>, as illustrated in <FIG>.

On the other hand, on a surface of the core mold <NUM> of the first injection molding unit 31b, protrusions 41a that extend along the axis direction are formed at equal intervals in the circumferential direction, and a transverse cross section of the core mold <NUM> forms an external gear shape, but this is not illustrated. Each of the protrusions 41a of this core mold <NUM> has a shape that corresponds to the groove 11b of the first layer, and by using the core mold <NUM> described above, the grooves 11b and the ridges 11d that each extend in the axis direction are formed in an inner periphery of the first layer <NUM>, as illustrated in <FIG>.

Note that <FIG> illustrate a vertical cross section of a portion of the protrusion 41a of the core mold <NUM>.

In addition, as illustrated in <FIG>, in the first injection molding unit 31b, a valve pin <NUM> that can move in the axis direction to a position close to the core mold <NUM> is provided in the interior of the hot runner mold <NUM>. The valve pin <NUM> is accommodated in the interior of the hot runner mold <NUM> until the mold space is filled with the first resin material, and the valve pin <NUM> protrudes to a position close to the core mold <NUM> after the mold space has been filled with the first resin material. The valve pin <NUM> moves at the time of injection molding, as described above, and therefore a thin film <NUM> in which the thickness of a resin material is smaller than the thickness of a peripheral part can be formed in a center of the bottom of the first layer <NUM>.

In addition, even when mold opening has been performed on the first injection molding unit <NUM>, the neck mold 36a of the conveyance mechanism <NUM> is not opened, and in this state, the first layer <NUM> of the preform <NUM> is held and conveyed. The number of preforms <NUM> to be simultaneously molded by the first injection molding unit <NUM> (that is, the number of containers <NUM> that can be simultaneously molded by the blow-molding apparatus <NUM>) can be appropriately set.

The second injection molding unit <NUM> includes a mold for second injection molding that includes a cavity mold <NUM>, a core mold <NUM>, and a hot runner mold <NUM>, and the second injection molding unit <NUM> injection-molds the second layer <NUM> in an outer peripheral part or an inner peripheral part of the first layer <NUM>. The second injection molding unit <NUM> is connected to a second injection device <NUM> that supplies the second resin material to the hot runner mold <NUM>. In addition, the cavity mold <NUM> includes a fitting part (a position regulation part) 50b on a face on an opposite side of a face that faces the hot runner mold <NUM> (see <FIG> and <FIG>). The fitting part 50b includes a tapered part 50b1 having a shape that is roughly similar to a shape of the tapered part 36a1 of the neck mold 36a, and receives the tapered part 36a1 of the neck mold 36a by using the tapered part 50b1.

<FIG> illustrates a second injection molding unit 32a that molds the second layer <NUM> of the preform <NUM> in the first example (<FIG>). <FIG> illustrates a second injection molding unit 32b that molds the second layer <NUM> of the preform <NUM> in the second example (<FIG>). Note that herein, when the second injection molding units 32a and 32b do not need to be distinguished from each other, the second injection molding unit <NUM> is used as a generic term.

The second injection molding unit 32a accommodates the first layer <NUM> of the preform <NUM> that has been injection-molded by the first injection molding unit 31a. As illustrated in <FIG>, in a state where mold closing has been performed on the second injection molding unit 32a, a mold space is formed between a portion from the barrel to the bottom of the outer peripheral side of the first layer <NUM> and an inner face of the cavity mold <NUM>.

The core mold <NUM> illustrated in <FIG> is inserted into an inner layer (the first layer <NUM>) of the preform <NUM>, and holds the inner layer from the inside. The cavity mold <NUM> illustrated in <FIG> receives the inner layer into which the core mold <NUM> will be inserted, forms a mold space of an outer layer (the second layer <NUM>) between the cavity mold <NUM> and an outer peripheral face of the inner layer, and specifies an outer peripheral shape of the outer layer.

The mold space described above is filled with the second resin material from the second injection device <NUM> by using the hot runner mold <NUM>, and therefore the second layer <NUM> is formed in each of the portions of the grooves 11a of the first layer <NUM>. By doing this, the preform <NUM> in the first example is manufactured.

The second injection molding unit 32b accommodates the first layer <NUM> of the preform <NUM> that has been injection-molded by the first injection molding unit 31b. As illustrated in <FIG>, in a state where mold closing has been performed on the second injection molding unit 32b, a mold space is formed between the grooves 11b on the inner peripheral side of the first layer <NUM> and a surface of the core mold <NUM>.

The cavity mold <NUM> illustrated in <FIG> receives an outer layer (the first layer <NUM>) of the preform <NUM>, and holds the outer layer from the outside. The core mold <NUM> illustrated in <FIG> is inserted into an inside of the outer layer, forms a mold space of an inner layer (the second layer <NUM>) between the core mold <NUM> and an inner peripheral face of the outer layer, and specifies an inner peripheral shape of the inner layer.

The second injection device <NUM> fills the mold space described above with the second resin material by using the hot runner mold <NUM>, and therefore the second layer <NUM> is formed in each of the portions of the grooves 11b of the first layer <NUM>. By doing this, the preform <NUM> in the second example is manufactured. In addition, in the second injection molding unit <NUM>, a small mold space between the ridges 11c and the cavity mold <NUM> or between the ridges 11d and the core mold <NUM> may be provided, and a thin second layer <NUM> may also be formed on outer surfaces of the ridges 11c and 11d. It is preferable that a thickness of the second layer <NUM> in the ridge 11c or 11d be less than or equal to one fourth of a thickness in the groove 11a or 11b, and it is more preferable that the thickness of the second layer <NUM> in the ridge 11c or 11d be less than or equal to one fifth of the thickness in the groove 11a or 11b.

Note that <FIG> illustrates a vertical cross section in a position where the grooves 11b have been formed in the first layer <NUM>.

The temperature adjusting unit <NUM> includes a not-illustrated mold for temperature adjustment (a temperature adjusting pot or a temperature adjusting core). The temperature adjusting unit <NUM> accommodates the preform <NUM> conveyed from the second injection molding unit <NUM> in a mold unit in which temperature is maintained at a predetermined temperature, and therefore the temperature adjusting unit <NUM> makes temperature uniform or removes temperature deviation, and adjusts the temperature of the preform <NUM> to a temperature suitable for final blowing (for example, about <NUM> to <NUM>). In addition, the temperature adjusting unit <NUM> also has a function of cooling down the preform <NUM> in a high-temperature state after injection molding. Note that the temperature adjusting pot includes a fitting part (a position regulation part) that comes into contact with the neck mold 36a and can be fitted, and the fitting part includes a tapered part having a shape that is roughly similar to a shape of the tapered part 36a1 of the neck mold 36a.

The blow-molding unit <NUM> performs blow-molding on the preform <NUM> in which temperature has been adjusted by the temperature adjusting unit <NUM>, and manufactures the container <NUM>.

The blow-molding unit <NUM> includes a mold for blow-molding that includes blow cavity molds that are a pair of split molds that correspond to a shape of the container <NUM>, a bottom mold, and a stretching rod and an air introducing member (a blowing core, both are not illustrated). The blow-molding unit <NUM> performs blow-molding while stretching the preform <NUM>. This causes the preform <NUM> to be shaped into a shape of the blow cavity mold, and the container <NUM> can be manufactured. The pair of blow cavity molds include a fitting part (a position regulation part) that comes into contact with the neck mold 36a and can be fitted, and the fitting part includes a tapered part having a shape that is roughly similar to a shape of the tapered part 36a1 of the neck mold 36a.

The taking out unit <NUM> is configured to release the neck <NUM> of the container <NUM> manufactured by the blow-molding unit <NUM> from the neck mold 36a, and take out the container <NUM> to an outside of the blow-molding apparatus <NUM>. The taking out unit <NUM> includes a taking out rod (a mold for taking out) that is inserted from an opening of the neck mold 36a. The taking out rod includes a fitting part (a position regulation part) that can roughly abut onto the neck mold 36a.

Next, a container manufacturing method performed by the blow-molding apparatus <NUM> according to the present embodiment is described. <FIG> is a flowchart illustrating processes of the container manufacturing method.

First, as illustrated in <FIG> and <FIG>, in the first injection molding unit <NUM>, the first resin material is injected from the first injection device <NUM> into a mold space formed by the cavity mold <NUM>, the core mold <NUM>, and the neck mold 36a of the conveyance mechanism <NUM>, and the first layer <NUM> of the preform <NUM> is molded. In a case where the preform <NUM> in the first example is formed, the first injection molding unit 31a is used, and in a case where the preform <NUM> in the second example is formed, the first injection molding unit 31b is used.

In the first injection molding unit 31b, as illustrated in <FIG>, after the first layer <NUM> of the preform <NUM> has been molded, a process of causing the valve pin <NUM> to protrude to a position close to the core mold <NUM> is performed. By doing this, in the center of the bottom of the first layer <NUM>, the thin film <NUM> having a thickness that is smaller than a thickness of a peripheral part is formed.

Then, when mold opening has been performed on the first injection molding unit <NUM>, the transfer plate of the conveyance mechanism <NUM> rotates by a predetermined angle, and the first layer <NUM> of the preform <NUM> held by the neck mold 36a is conveyed to the second injection molding unit <NUM> in a state where residual heat at the time of injection molding is contained.

Next, the first layer <NUM> of the preform <NUM> is accommodated in the second injection molding unit <NUM>, and the second layer <NUM> is injection-molded. In a case where the preform <NUM> in the first example is formed, the second injection molding unit 32a is used, and in a case where the preform <NUM> in the second example is formed, the second injection molding unit 32b is used.

In the second injection molding unit 32a, as illustrated in <FIG>, a mold space is formed between the grooves 11a on the outer peripheral side of the first layer <NUM> and the cavity mold <NUM> that faces the outer periphery of the first layer <NUM>. The mold space described above is filled with the second resin material by using the hot runner mold <NUM>.

In <FIG>, the core mold <NUM> is inserted on the inner peripheral side of the first layer <NUM>, and the core mold <NUM> holds a shape of the first layer <NUM> from the inner peripheral side. Therefore, even if the second resin material comes into contact with the first layer <NUM>, heat deformation of the first layer <NUM> can be avoided. In a case where the preform <NUM> in the first example is molded by doing the above, the second layer <NUM> can be formed on the outer peripheral side of the first layer <NUM>.

In contrast, in the second injection molding unit 32b, as illustrated in <FIG>, a mold space is formed between the grooves 11b on the inner peripheral side of the first layer <NUM> and the core mold <NUM> that faces the inner periphery of the first layer <NUM>. The mold space described above is filled with the second resin material by using the hot runner mold <NUM>. Note that the thin film <NUM> has been formed in the bottom of the first layer <NUM>. However, the thin film <NUM> is broken due to injection pressure of the second resin material, a hole <NUM> is formed in the bottom, and the second resin material is guided from the hole <NUM> described above to the inner peripheral side of the first layer <NUM>.

In <FIG>, the cavity mold <NUM> faces the outer peripheral side of the first layer <NUM>, and the cavity mold <NUM> holds a shape of the first layer <NUM> from the outer peripheral side. Therefore, even if the second resin material comes into contact with the first layer <NUM>, heat deformation of the first layer <NUM> can be avoided. In a case where the preform <NUM> in the second example is molded by doing the above, the second layer <NUM> can be formed on the inner peripheral side of the first layer <NUM>.

Note that the first layer <NUM> in the second injection molding process has residual heat at the time of injection molding, and is relatively easily deformable. Therefore, if the second resin material is injected into the mold space, air in the mold space is pushed out in an upward direction while slightly elastically deforming the first layer <NUM>, and is exhausted. Thus, air accumulation is not likely to be generated at the time of molding the second layer <NUM>, and this avoids defective molding of the preform <NUM>.

As described above, by performing the first injection molding process and the second injection molding process, the preform <NUM> in the first example or the second example is manufactured.

Then, when mold opening has been performed on the second injection molding unit <NUM>, the transfer plate of the conveyance mechanism <NUM> rotates by a predetermined angle, and the preform <NUM> held by the neck mold 36a is conveyed to the temperature adjusting unit <NUM> in a state where residual heat at the time of injection molding is contained.

Next, in the temperature adjusting unit <NUM>, the preform <NUM> is accommodated in a mold unit for temperature adjustment, and temperature adjusting process is performed to make the temperature of the preform <NUM> closer to a temperature suitable for final blowing. Then, the transfer plate of the conveyance mechanism <NUM> rotates by a predetermined angle, and the preform <NUM> after temperature adjustment that has been held by the neck mold 36a is conveyed to the blow-molding unit <NUM>.

Next, in the blow-molding unit <NUM>, the container <NUM> is blow-molded.

First, mold closing is performed on the blow cavity mold to accommodate the preform <NUM> in mold space, and the air introducing member (the blowing core) is lowered, and therefore the air introducing member abuts onto the neck <NUM> of the preform <NUM>. Then, the stretching rod is lowered, the bottom <NUM> of the preform <NUM> is pressed down from an inner face, and blowing air is supplied from the air introducing member while performing longitudinal-axis stretching as needed, and therefore lateral-axis stretching is performed on the preform <NUM>. By doing this, the preform <NUM> swells out and is shaped to come into close contact with the mold space of the blow cavity mold, and the container <NUM> is blow-molded. Note that in a case where the preform <NUM> is longer than the container <NUM>, the bottom mold is caused to stand by in a lower position that does not come into contact with the bottom of the preform <NUM> before mold closing of the blow cavity mold, and is quickly elevated to a molding position after mold closing.

In addition, in the present embodiment, the preform <NUM> in the first example or the second example is blow-molded, and therefore a container <NUM> having a vertical-striped pattern in which color changes in the circumferential direction according to stretching of the first layer <NUM> and the second layer <NUM> is manufactured.

When blow-molding has been finished, mold opening is performed on the blow cavity mold. This enables the container <NUM> to move from the blow-molding unit <NUM>.

Next, the transfer plate of the conveyance mechanism <NUM> rotates by a predetermined angle, and the container <NUM> is conveyed to the taking out unit <NUM>. In the taking out unit <NUM>, the neck <NUM> of the container <NUM> is released from the neck mold 36a, and the container <NUM> is taken out to an outside of the blow-molding apparatus <NUM>.

By doing the above, a single cycle of the container manufacturing method terminates. Then, by rotating the transfer plate of the conveyance mechanism <NUM> by a predetermined angle, the respective processes described above of S101 to S105 are repeated. Note that during the operation of the blow-molding apparatus <NUM>, five containers are manufactured in parallel at every time difference of a single process.

In addition, for the sake of a structure of the blow-molding apparatus <NUM>, respective time periods of the first injection molding process, the second injection molding process, the temperature adjusting process, the blow-molding process, and the container taking out process have the same length. Similarly, time periods of conveyance between the respective processes have the same length.

As described above, in the present embodiment, in the first injection molding process, a first layer <NUM> of a preform <NUM> is injection-molded, and in the second injection molding process, a second layer <NUM> is injection-molded in the grooves 11a or 11b on the inner peripheral side or the outer peripheral side of the first layer <NUM>, and a preform <NUM> having a multilayer structure is manufacture. In the present embodiment, each of the preforms <NUM> having a multilayer structure is molded in two stages of injection molding, and therefore shapes and thickness distributions of the grooves 11a or 11b of the first layer <NUM> and the second layer <NUM> formed in the grooves 11a or 11b can be precisely controlled. This enables a vertical-striped pattern to be stably formed in a container <NUM> by performing internal coloring.

In addition, in the present embodiment, a preform <NUM> having a multilayer structure is manufactured in two stages of injection molding, the preform <NUM> is blow-molded in a state where residual heat at the time of injection molding is contained, and a container <NUM> is manufactured. Therefore, a device configuration of each injection molding unit or control performed on each of the injection molding units can be made simple in comparison with a case where a preform having a multilayer structure is manufactured in one injection molding, and therefore a manufacturing cost of a container can be reduced.

In addition, for example, in comparison with a case where cooled preforms are fitted, a preform having a multilayer structure is manufactured, and after reheating, blow-molding is performed (a cold parison method), in the case of the present embodiment, a preform does not need to be cooled down to a temperature close to ordinary temperature, and neither is a process of assembling or reheating the preform needed. Therefore, according to the present embodiment, a series of processes from injection molding of a preform <NUM> to blow-molding of a container <NUM> can be completed in a relatively short time, and a container <NUM> having a vertical-striped pattern can be manufactured in a shorter cycle.

The present invention is not limited to the embodiment described above, and various improvements and changes in design may be made without departing from the spirit of the present invention.

In the present embodiment, an example has been described where a preform <NUM> having a two-layer structure is molded in two stages of injection molding, and this preform <NUM> is blow-molded. However, in a blow-molding apparatus <NUM> according to the present invention, an injection molding unit may be further added, and a preform having an n-layer structure may be molded in n-stages of injection molding (where n is an integer of <NUM> or more). By doing this, a container having a color pattern of more complicated color arrangement can be manufactured. Note that in a case where three or more injection molding units are provided, in order to adjust the temperature of residual heat in each layer to a preferable temperature, a temperature adjusting unit may be appropriately added between the injection molding units.

In addition, a striped pattern according to the present invention is not limited to the examples in the embodiment described above. As an example, <FIG> is a variation of <FIG>, and illustrates a transverse cross section of a preform <NUM> in which two grooves 11a (ridges 11c) have been formed at intervals of <NUM>° in the outer periphery of the first layer <NUM>. In a case where the preform <NUM> of <FIG> has been blow-molded, a container <NUM> having a color pattern of two vertical stripes is formed. Note that in a case where the same type of container is formed, the grooves 11b, the ridges 11d, and the second layer <NUM> may be formed in the inner periphery of the first layer <NUM>. In addition, the first layer <NUM> in which the ridges 11c or the grooves 11b are formed is transparent (has a light transmissive property), and therefore a barrel of a container <NUM> that corresponds to the ridges 11c or the grooves 11b also serves as a portion where a residual amount of contents can be checked.

In addition, <FIG> is a variation of <FIG>, and illustrates a transverse cross section of a preform <NUM> in which a depth of the groove 11b changes in a curved manner in the circumferential direction. In a case where the preform <NUM> of <FIG> has been blow-molded, a periodical gradation having a vertical-striped shape can be generated in the circumferential direction of a container <NUM> in accordance with a change in thickness in the circumferential direction of the second layer <NUM>. Note that in a case where the same type of container is formed, the grooves 11a and the second layer <NUM> may be formed in the outer periphery of the first layer <NUM>.

Further, in <FIG>, the ridges 11d of the first layer may have a shape that protrudes toward a center axis of the container <NUM>, and protruding ribs may be formed inside the container. It is preferable that the protruding ribs to be formed inside the container <NUM> be formed to extend at least from a lower side of the barrel <NUM> to an inside of the bottom <NUM>, and the protruding ribs be provided at roughly equal intervals. By doing this, a degree of rigidity or pressure resistance of the container <NUM> can be enhanced.

Note that the specifications such as the number of grooves, a width of the groove, or an interval between grooves in each of the variations can be arbitrarily changed.

In addition, in the embodiment described above, a configuration example of what is called a five-station type blow-molding apparatus <NUM> has been described. However, a blow-molding apparatus according to the present invention may be a six-station type blow-molding apparatus that includes a temperature adjusting unit that auxiliarily heats or cools down the first layer <NUM> of the preform <NUM>, between the first injection molding unit <NUM> and the second injection molding unit <NUM>.

<FIG> is a diagram schematically illustrating a configuration example of a six-station type blow-molding apparatus 30a serving as another embodiment. In addition, <FIG> is a flowchart illustrating processes of a container manufacturing method according to the other embodiment. Note that in the description below of the other embodiment, a duplicate description relating to an element that is similar to an element of the embodiment described above is appropriately omitted.

The blow-molding apparatus 30a illustrated in <FIG> includes a first injection molding unit <NUM>, a temperature adjusting unit <NUM> (a first temperature adjusting unit), a second injection molding unit <NUM>, a temperature adjusting unit <NUM> (a second temperature adjusting unit), a blow-molding unit <NUM>, a taking out unit <NUM>, and a conveyance mechanism <NUM>. The first injection molding unit <NUM>, the temperature adjusting unit <NUM>, the second injection molding unit <NUM>, the temperature adjusting unit <NUM>, the blow-molding unit <NUM>, and the taking out unit <NUM> are disposed in positions that have been displaced in a rotating manner by every predetermined angle (for example, every <NUM> degrees) with the conveyance mechanism <NUM> as a center.

The conveyance mechanism <NUM> of the blow-molding apparatus 30a includes a transfer plate 36b that rotates about an axis in a sheet vertical direction in <FIG> as a center. The transfer plate 36b conveys the preform <NUM> (or the container <NUM>) in which a neck is held by a neck mold to the first injection molding unit <NUM>, the temperature adjusting unit <NUM>, the second injection molding unit <NUM>, the temperature adjusting unit <NUM>, the blow-molding unit <NUM>, and the taking out unit <NUM> in this order.

In addition, the temperature adjusting unit <NUM> has a configuration that is roughly similar to a configuration of the temperature adjusting unit <NUM>, and includes a not-illustrated mold for temperature adjustment (a temperature adjusting pot or a temperature adjusting core). The temperature adjusting unit <NUM> accommodates the first layer <NUM> of the preform <NUM> conveyed from the first injection molding unit <NUM> in a mold unit that is maintained at a predetermined temperature, and therefore the temperature adjusting unit <NUM> auxiliarily heats or cools down the first layer <NUM>.

As illustrated in <FIG>, a container manufacturing method performed by the blow-molding apparatus 30a according to the other embodiment is different from the manufacturing method according to the embodiment described above illustrated in <FIG> in that a first temperature adjusting process (S101a) is performed between the first injection molding process (S101) and the second injection molding process (S102).

In the first temperature adjusting process (S101a), in the temperature adjusting unit <NUM>, the first layer <NUM> of the preform <NUM> is accommodated in the mold unit for temperature adjustment, the first layer <NUM> is cooled down, and a temperature distribution is adjusted (temperature is made uniform, or temperature deviation is removed). At this time, in the temperature adjusting unit <NUM>, the first layer <NUM> may be heated as needed.

Claim 1:
A manufacturing method of a resin container, the manufacturing method comprising:
a first injection molding process (S101) for injection-molding a first layer (<NUM>) of a preform (<NUM>) by using a first resin material, the first layer of the preform having a bottomed cylindrical shape and including a groove (<NUM>) that extends in an axis direction;
a second injection molding process (S102) for injecting a second resin material into the groove (<NUM>) of the first layer, the second resin material having a color that is different from a color of the first resin material, and laminating a second layer (<NUM>) on an outer peripheral side or an inner peripheral side of the first layer; and
a blow-molding process (S104) for blow-molding a preform that includes multiple layers and has been obtained in the second injection molding process in a state where residual heat at a time of injection molding is contained, and manufacturing the resin container having a vertical-striped color pattern formed by using the second layer.