JP6413569B2 - Composite container manufacturing method, composite preform, composite container, and bottom protective member - Google Patents

Description

  The present invention relates to a composite container manufacturing method, a composite preform, a composite container, and a bottom protective member.

  Recently, plastic bottles for storing content liquids such as foods and drinks have become common, and such plastic bottles store content liquids.

  A plastic bottle containing such a content liquid is manufactured by inserting a preform into a mold and biaxially stretch-blow molding.

JP 2009-241526 A

  By the way, conventionally, after filling a plastic bottle with the content liquid and capping the mouth, the plastic bottle may be conveyed by a conveying device coated with a lubricant in an upright state. At this time, an alkaline lubricant adheres to the bottom of the plastic bottle. For this reason, when the bottom part of the plastic bottle is damaged by the lubricant and stress is applied to the bottom part during storage of the plastic bottle, a stress crack may occur. Therefore, among plastic bottles, in particular, there is a demand for increasing the environmental stress crack resistance (also referred to as “ESCR”) at the bottom. It is known that ESCR is a phenomenon in which a plastic bottle is cracked when subjected to stress, and is further promoted in a state where chemicals such as the lubricant are adhered.

  The present invention has been made in consideration of such points, and can improve the environmental stress fracture resistance (ESCR) at the bottom of a plastic bottle (composite container), a composite container manufacturing method, a composite preform, It aims at providing a composite container and a bottom part protection member.

  The present invention relates to a method of manufacturing a composite container, the step of preparing a preform made of plastic material, the step of providing a bottom protective member made of polyolefin resin on the outside of the preform, the preform and the bottom portion protection And a step of inflating the preform and the bottom protection member integrally by performing blow molding on the member, the preform having a mouth portion, a trunk portion, and a bottom portion, and the bottom protection member Is a method for producing a composite container, characterized in that it is provided so as to cover at least the bottom of the preform.

  The present invention is the method of manufacturing a composite container, wherein the bottom protective member includes a polyethylene resin or a polypropylene resin.

  The present invention is the method of manufacturing a composite container, wherein the bottom protective member has an action of contracting with respect to the preform.

  The present invention provides a composite preform comprising a preform made of a plastic material and a bottom protective member made of polyolefin resin provided on the outside of the preform, and the preform includes a mouth portion, a trunk portion, and a bottom portion. And the bottom protection member is provided so as to cover at least the bottom of the preform.

  The present invention is the composite preform, wherein the bottom protective member includes a polyethylene resin or a polypropylene resin.

  The present invention is the composite preform, wherein the bottom protective member has a function of contracting with respect to the preform.

  The present invention, in a composite container, comprising a container body made of plastic material, and a bottom protective member made of polyolefin resin provided in close contact with the outside of the container body, the container body and the bottom protection member, The container body is inflated integrally by blow molding, the container body has a mouth portion, a body portion, and a bottom portion, and the bottom protection member is provided so as to cover at least the bottom portion of the container body. It is the characteristic composite container.

  The present invention is the composite container, wherein the bottom protection member includes a polyethylene resin or a polypropylene resin.

  The present invention is the composite container, wherein the bottom protective member has a contracting action.

  The present invention is a composite container having the preform and a bottom protective member that is in close contact with the outside of the preform by being attached to the outside of the preform made of a plastic material and inflated together with the preform. Is a bottom protective member made of a polyolefin-based resin and having a bottom portion that covers at least the bottom portion of the preform.

  ADVANTAGE OF THE INVENTION According to this invention, the environmental stress destruction resistance (ESCR) of the bottom part of a plastic bottle (composite container) can be improved.

FIG. 1 is a partial vertical sectional view showing a composite container according to an embodiment of the present invention. FIG. 2 is a horizontal sectional view (sectional view taken along the line II-II in FIG. 1) showing the composite container according to the embodiment of the present invention. FIG. 3 is a partial vertical sectional view showing a composite preform according to an embodiment of the present invention. 4A to 4F are schematic views illustrating a method for manufacturing a composite container according to an embodiment of the present invention. Fig.5 (a)-(c) is the schematic which shows the filling method of a composite container. 6A to 6F are schematic views showing a method for manufacturing a composite container according to a modification of the embodiment of the present invention. 7A to 7G are schematic views illustrating a method for manufacturing a composite container according to a modification of the embodiment of the present invention.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1 to 7 show an embodiment of the present invention.

  First, an outline of a composite container produced by the composite container manufacturing method (blow molding method) according to the present embodiment will be described with reference to FIGS. 1 and 2. In the present specification, “upper” and “lower” refer to the upper side and the lower side in a state where the composite container 10A is erected (FIG. 1), respectively.

  A composite container 10A shown in FIGS. 1 and 2 is biaxially stretched with respect to a composite preform 70 (see FIG. 3) including a preform 10a and a bottom protection member 40a using a blow mold 50, as will be described later. By performing blow molding, the preform 10a and the bottom protection member 40a of the composite preform 70 are expanded as a unit.

  Such a composite container 10 </ b> A includes a container body 10 made of a plastic material located on the inner side, and a bottom protective member 40 made of polyolefin resin that is provided in close contact with the outer side of the container body 10.

  Among these, the container body 10 includes a mouth portion 11, a neck portion 13 provided below the mouth portion 11, a shoulder portion 12 provided below the neck portion 13, a trunk portion 20 provided below the shoulder portion 12, And a bottom portion 30 provided below the portion 20.

  On the other hand, the bottom protection member 40 is in close contact with the outer surface of the container main body 10 in a thinly extended state, and is attached to the container main body 10 without being easily moved or rotated. In this case, the bottom protection member 40 is provided so as to cover the lower portion of the trunk portion 20 and the entire area of the bottom portion 30.

  Next, the container body 10 will be described in detail. As described above, the container body 10 includes the mouth portion 11, the neck portion 13, the shoulder portion 12, the trunk portion 20, and the bottom portion 30.

  Of these, the mouth portion 11 includes a screw portion 14 screwed into a cap (not shown) and a flange portion 17 provided below the screw portion 14. The shape of the mouth portion 11 may be a conventionally known shape.

  The neck portion 13 is located between the flange portion 17 and the shoulder portion 12 and has a substantially cylindrical shape having a substantially uniform diameter. The shoulder 12 is located between the neck 13 and the trunk 20 and has a shape whose diameter gradually increases from the neck 13 toward the trunk 20.

  Furthermore, the trunk | drum 20 has a cylindrical shape with a substantially uniform diameter as a whole. However, the present invention is not limited to this, and the body portion 20 may have a polygonal cylindrical shape such as a rectangular cylindrical shape or an octagonal cylindrical shape. Or the trunk | drum 20 may have a cylinder shape with a horizontal cross section which is not uniform toward upper direction from the downward direction. Moreover, in this Embodiment, although the unevenness | corrugation is not formed in the trunk | drum 20, and has a substantially flat surface, it is not restricted to this. For example, unevenness such as a panel or a groove may be formed on the body portion 20.

  On the other hand, the bottom portion 30 has a concave portion 31 located in the center and a grounding portion 32 provided around the concave portion 31. The shape of the bottom 30 is not particularly limited, and may have a conventionally known bottom shape (for example, a petaloid bottom shape or a round bottom shape).

  Moreover, although the thickness of the container main body 10 in the trunk | drum 20 is not limited to this, For example, it can be made thin to about 50 micrometers-250 micrometers. Further, the weight of the container body 10 is not limited to this, but can be 10 g to 20 g. Thus, by reducing the thickness of the container main body 10, the weight of the container main body 10 can be reduced.

  Such a container main body 10 can be manufactured by biaxially stretching blow-molding a preform 10a (described later) manufactured by injection molding a synthetic resin material. As the material of the preform 10a, that is, the container body 10, a thermoplastic resin, particularly PE (polyethylene), PP (polypropylene), PET (polyethylene terephthalate), PEN (polyethylene naphthalate), or PC (polycarbonate) may be used. preferable. The container body 10 may be colored in colors such as red, blue, yellow, green, brown, black, and white, but is preferably colorless and transparent in consideration of ease of recycling. Moreover, you may blend and use the various resin mentioned above. Further, a vapor deposition film such as a diamond-like carbon film or a silicon oxide thin film may be formed on the inner surface of the container body 10 in order to enhance the barrier property of the container.

  The container body 10 can also be formed as a multilayer molded bottle having two or more layers. That is, by extrusion molding or injection molding, for example, the intermediate layer has gas barrier properties and light shielding properties such as MXD6, MXD6 + fatty acid salt, PGA (polyglycolic acid), EVOH (ethylene vinyl alcohol copolymer) or PEN (polyethylene naphthalate). You may form as a multilayer bottle which has gas barrier property and light-shielding property by extrusion-molding preform 10a which consists of three or more layers as resin which it has (intermediate layer), and carrying out blow molding. As the intermediate layer, a resin obtained by blending the above-described various resins may be used.

  Further, by mixing an inert gas (nitrogen gas, argon gas) with the thermoplastic resin melt, a foam preform having a foam cell diameter of 0.5 to 100 μm is formed, and this foam preform is blow-molded. Thus, the container body 10 may be manufactured. Since such a container main body 10 contains the foam cell, the light shielding property of the container main body 10 whole can be improved.

  Such a container main body 10 may consist of a bottle with a full capacity of 100 ml to 2000 ml, for example. Alternatively, the container main body 10 may be a large bottle having a full capacity of, for example, 10L to 60L.

  Next, the bottom protection member 40 will be described. The bottom protective member 40 (40a) is provided so as to surround the outside of the preform 10a as will be described later, and is obtained by being in close contact with the outside of the preform 10a and then being biaxially stretch blow-molded together with the preform 10a. It is a thing.

  The bottom protection member 40 is attached to the outer surface of the container body 10 without being bonded, and is in close contact with the container body 10 so as not to move or rotate. The bottom protective member 40 is thinly extended on the outer surface of the container body 10 to cover the container body 10. Moreover, as shown in FIG. 2, the bottom part protection member 40 is provided over the whole circumferential direction so that the container main body 10 may be surrounded, and has a substantially circular horizontal cross section.

  In this case, the bottom protection member 40 is provided so as to cover the lower portion of the trunk portion 20 and the entire area of the bottom portion 30 in the container body 10. Thereby, the thickness of the whole area of the lower part of the trunk | drum 20 and the bottom part 30 is increased, and the intensity | strength of this area | region is raised.

  In addition, the bottom part protection member 40 should just be provided so that the bottom part 30 may be covered at least among the container main bodies 10. FIG. For example, the bottom part protection member 40 may be provided so as to cover the entire neck part 13, shoulder part 12, trunk part 20, and bottom part 30 except for the mouth part 11 in the container body 10. Or the bottom part protection member 40 may be provided so that only the bottom part 30 among the container main bodies 10 may be covered. Furthermore, the bottom protective member 40 is not limited to one, and a plurality of bottom protective members 40 may be provided.

  On the other hand, since the bottom protection member 40 is not welded or bonded to the container body 10, it can be peeled off from the container body 10. Specifically, for example, the bottom protection member 40 may be cut using a blade or the like, or a cutting line (not shown) may be provided in advance in the bottom protection member 40, and the bottom protection member 40 may be peeled along the cutting line. it can. Thereby, since the bottom part protection member 40 can be separated and removed from the container main body 10, the colorless and transparent container main body 10 can be recycled as in the conventional case.

  Such a bottom protection member 40 may have no contracting action on the preform 10a or may have a contracting action.

  When the bottom protection member 40 has a function of contracting with respect to the preform 10a, the bottom protection member (outer contraction member) 40 is provided on at least a part of the outside of the preform 10a, and is integrated with the preform 10a. And heated and biaxially stretch blow molded.

  Moreover, the thickness of the bottom part protection member 40 can be appropriately changed as necessary, and is not limited thereto, but can be set to, for example, about 5 μm to 500 μm in a state of being attached to the container body 10. .

  Next, the structure of the composite preform according to this embodiment will be described with reference to FIG.

  As shown in FIG. 3, the composite preform 70 includes a preform 10a made of a plastic material and a bottom protective member 40a made of a bottomed cylindrical polyolefin resin and provided outside the preform 10a. Yes.

  Among these, the preform 10a includes a mouth portion 11a, a body portion 20a connected to the mouth portion 11a, and a bottom portion 30a connected to the body portion 20a. Of these, the mouth portion 11 a corresponds to the mouth portion 11 of the container body 10 described above, and has substantially the same shape as the mouth portion 11. Moreover, the trunk | drum 20a respond | corresponds to the neck part 13, the shoulder part 12, and the trunk | drum 20 of the container main body 10 mentioned above, and has a substantially cylindrical shape. The bottom 30a corresponds to the bottom 30 of the container body 10 described above, and has a substantially hemispherical shape. As described above, the preform 10a may be made of a thermoplastic resin such as PE (polyethylene), PP (polypropylene), PET (polyethylene terephthalate), PEN (polyethylene naphthalate), or PC (polycarbonate).

  The bottom protection member 40a is attached to the outer surface of the preform 10a without being adhered, and is in close contact with the preform 10a so as not to move or rotate, or in close contact with the preform 10a so that it does not fall under its own weight. . The bottom protection member 40a is provided over the entire circumferential direction so as to surround the preform 10a, and has a circular horizontal cross section.

  In this case, the bottom protection member 40a is provided so as to cover the lower portion of the trunk portion 20a and the entire area of the bottom portion 30a.

  The bottom protection member 40a is provided so as to cover at least the bottom 30a of the preform 10a. For example, the bottom part protection member 40a may be provided so as to cover the entire body part 20a and the bottom part 30a except for the mouth part 11a. Or the bottom part protection member 40a may be provided so that only the bottom part 30a may be covered among the preforms 10a. Furthermore, the number of bottom protection members 40a is not limited to one, and a plurality of bottom protection members 40a may be provided.

  Such a bottom protecting member 40a may have no contracting action on the preform 10a or may have a contracting action.

  In the former case, as the bottom protective member 40a, for example, a blow tube produced by blow molding, a sheet molded tube produced by sheet molding, an extruded tube produced by extrusion molding, an inflation molded tube produced by inflation molding, etc. However, the present invention is not limited to this, and molding methods other than those described above may be used.

  On the other hand, when the bottom protection member (outer contraction member) 40a has a contracting action, the bottom protection member (outer contraction member) 40a is applied to the preform 10a when an external action (for example, heat) is applied, for example. What shrinks | contracts with respect (for example, heat shrink) may be used. Alternatively, the bottom portion protection member (outer contraction member) 40a may itself be contractible or elastic and contractable without applying an external action.

  The bottom protective member 40a is made of, for example, a polyolefin resin such as a polyethylene resin or a polypropylene resin. Specifically, the polyolefin-based resin includes a high-density polyethylene resin, a medium-density polyethylene resin, a polyethylene resin such as a low-density polyethylene resin, a crystalline propylene homopolymer, a crystalline propylene / ethylene random copolymer, Mainly olefin components such as crystalline propylene / α-olefin random copolymer, polypropylene block resin such as crystalline block copolymer of propylene and ethylene and / or α-olefin, and ethylene-vinyl acetate copolymer And a blend resin mainly composed of a polyolefin resin component. Furthermore, various additives may be added to the material of the bottom protective member 40a in addition to the main component resin, as long as the characteristics are not impaired. Examples of additives include plasticizers, UV stabilizers, anti-coloring agents, matting agents, deodorants, flame retardants, weathering agents, antistatic agents, yarn friction reducing agents, slip agents, mold release agents, An oxidizing agent, an ion exchange agent, a coloring pigment, and the like can be added.

  In addition, although the thickness of the bottom part protection member 40a can be suitably set according to the increase in thickness with respect to 10 A of composite containers, it is good also as 0.005 mm-0.5 mm, for example.

  Next, a manufacturing method (blow molding method) of the composite container 10A according to the present embodiment will be described with reference to FIGS.

  First, a preform 10a made of a plastic material is prepared (see FIG. 4A). In this case, for example, the preform 10a may be manufactured by an injection molding method using an unillustrated injection molding machine. As the preform 10a, a commonly used preform may be used.

  Next, a bottom protective member 40a made of polyolefin resin is provided outside the preform 10a. As a result, a composite preform 70 having the preform 10a and the bottom protective member 40a in close contact with the outside of the preform 10a is produced (see FIG. 4B). In this case, the bottom protection member 40a has a bottomed cylindrical shape as a whole, is connected to the cylindrical body 41 covering the lower part of the body 20a of the preform 10a, and the body 41, and covers the entire area of the bottom 30a. A hemispherical bottom 42.

  At this time, the bottom protective member 40a having an inner diameter that is the same as or slightly smaller than the outer diameter of the preform 10a may be brought into close contact with the outer surface of the preform 10a by being pushed into the preform 10a. Alternatively, as will be described later, a heat-shrinkable bottom protective member 40a is provided on the outer surface of the preform 10a, and the bottom protective member 40a is thermally contracted by heating to 50 ° C. to 100 ° C. You may make it stick to.

  As described above, the bottom protective member 40a is brought into close contact with the outside of the preform 10a in advance, and the composite preform 70 is prepared, whereby a series of steps for manufacturing the composite preform 70 (FIGS. 4A to 4B). )) And a series of steps (FIGS. 4 (c) to (f)) for producing the composite container 10A by blow molding can be performed at different places (a factory or the like).

  Next, the composite preform 70 is heated by the heating device 51 (see FIG. 4C). At this time, the composite preform 70 is evenly heated in the circumferential direction by the heating device 51 while rotating with the mouth portion 11a facing downward. The heating temperature of the preform 10a and the bottom protection member 40a in this heating process may be 90 ° C. to 130 ° C., for example.

  Subsequently, the composite preform 70 heated by the heating device 51 is sent to the blow molding die 50 (see FIG. 4D).

  The composite container 10 </ b> A is molded using this blow molding die 50. In this case, the blow mold 50 includes a pair of body molds 50a and 50b and a bottom mold 50c that are divided from each other (see FIG. 4D). In FIG. 4D, the pair of body molds 50a and 50b are open to each other, and the bottom mold 50c is raised upward. In this state, the composite preform 70 is inserted between the pair of body molds 50a and 50b.

  Next, as shown in FIG. 4 (e), after the bottom mold 50c is lowered, the pair of body molds 50a, 50b is closed and sealed by the pair of body molds 50a, 50b and the bottom mold 50c. A blow mold 50 is formed. Next, air is press-fitted into the preform 10 a and biaxial stretch blow molding is performed on the composite preform 70.

  As a result, the container body 10 is obtained from the preform 10 a in the blow molding die 50. During this time, the body molds 50a and 50b are heated to 30 ° C. to 80 ° C., and the bottom mold 50c is cooled to 5 ° C. to 25 ° C. At this time, in the blow molding die 50, the preform 10a and the bottom protection member 40a of the composite preform 70 are expanded as a unit. Thereby, the preform 10a and the bottom protection member 40a are integrally formed into a shape corresponding to the inner surface of the blow molding die 50.

  In this manner, a composite container 10A including the container body 10 and the bottom protection member 40 provided on the outer surface of the container body 10 is obtained.

  Next, as shown in FIG. 4 (f), the pair of body molds 50 a and 50 b and the bottom mold 50 c are separated from each other, and the composite container 10 </ b> A is taken out from the blow molding mold 50.

  Next, the filling method of the composite container 10A will be described with reference to FIGS.

  First, the composite container 10A is manufactured by the method shown in FIGS. 4A to 4F, for example. Next, the inside of the container body 10 is sterilized by spraying a sterilizing agent such as hydrogen peroxide or peracetic acid onto the composite container 10A. Alternatively, the interior of the container body 10 may be sterilized by irradiating the composite container 10A with an electron beam or ultraviolet rays.

  Subsequently, the contents L such as a beverage are filled into the container body 10 from the mouth portion 11 of the composite container 10A (FIG. 5A). Thereafter, by attaching the cap 18 to the mouth portion 11 of the composite container 10A, the content container 10B including the composite container 10A, the content L, and the cap 18 is obtained (FIG. 5B).

  The plurality of content-containing containers 10B obtained in this way are conveyed downstream by a conveying device 65 such as a conveyor in an upright state (FIG. 5C). In this case, a lubricant G is applied to the upper surface of the transport device 65 to facilitate transport of the content container 10B. For this reason, the lubricant G adheres to the bottom surface of the content container 10B. The lubricant G contains an alkaline component having a pH of 7.0 to 10.0, for example.

  On the other hand, in this Embodiment, the bottom part protection member 40 made from polyolefin resin is provided so that the bottom part 30 of the container main body 10 of the content container 10B may be covered. In general, the polyolefin-based resin constituting the bottom protective member 40 is superior in chemical resistance to the alkaline lubricant G as compared with a plastic material (for example, polyethylene terephthalate) constituting the container body 10. For this reason, the bottom part 30 of the container body 10 is protected by the bottom part protection member 40, thereby preventing the bottom part 30 from being damaged by the lubricant G. As a result, even if stress is applied during storage of the content container 10B, there is no possibility that stress cracks will occur in the bottom 30. Thus, in this Embodiment, the environmental stress fracture tolerance (ESCR) of the bottom part 30 of the container main body 10 is improved.

Modified Example of Manufacturing Method of Composite Container Next, a modified example of the manufacturing method (blow molding method) of the composite container 10A according to the present embodiment will be described with reference to FIGS. The modification shown in FIGS. 6A to 6F has an action in which the bottom protective member (outer contraction member) 40a contracts with respect to the preform 10a, and the other configuration is shown in FIG. It is substantially the same as the form shown in (f). 6A to 6F, the same parts as those in FIGS. 4A to 4F are denoted by the same reference numerals, and detailed description thereof is omitted.

  First, a preform 10a made of a plastic material is prepared (see FIG. 6A).

  Next, a bottom protective member (outer contraction member) 40a made of polyolefin resin is provided on the outside of the preform 10a (see FIG. 6B). In this case, the bottom part protection member (outside contraction member) 40a has a bottomed cylindrical shape as a whole, and includes a cylindrical body part 41 and a bottom part 42 connected to the body part 41. The bottom protection member (outer contraction member) 40a is mounted so as to cover the lower portion of the trunk portion 20a and the entire area of the bottom portion 30a.

  Next, the preform 10a and the bottom protection member (outer contraction member) 40a are heated by the heating device 51 (see FIG. 6C). At this time, the preform 10a and the bottom protection member (outer contraction member) 40a are evenly heated in the circumferential direction by the heating device 51 while rotating with the mouth portion 11a facing downward. The heating temperature of the preform 10a and the bottom protection member (outer contraction member) 40a in this heating step may be, for example, 90 ° C. to 130 ° C.

  In this way, the bottom protection member (outer contraction member) 40a is heated, so that the bottom protection member (outer contraction member) 40a is thermally contracted and is in close contact with the outside of the preform 10a (see FIG. 6C). .

  Subsequently, the preform 10a and the bottom protection member (outer contraction member) 40a heated by the heating device 51 are sent to the blow molding die 50 (see FIG. 6 (d)).

  The preform 10a and the bottom protection member (outer contraction member) 40a are molded using this blow molding die 50, and are substantially the same as those in FIGS. 4 (a) to 4 (f) described above. Thus, a composite container 10A including a bottom protective member (outer contraction member) 40 provided on the outer surface of the container body 10 is obtained (see FIGS. 6D to 6F). Thereafter, the composite container 10A is filled with the content L, and the cap 18 is attached to the mouth portion 11, whereby the content container 10B is obtained. 6F and the subsequent steps are the same as those shown in FIGS. 5A to 5C described above, and thus detailed description thereof is omitted here.

  Next, with reference to FIGS. 7A to 7G, another modification of the method for manufacturing the composite container 10A (blow molding method) according to the present embodiment will be described. 7 (a) to 7 (g) has an effect that the bottom protection member (outer contraction member) 40a contracts with respect to the preform 10a, and the preform 10a and the bottom protection member (outer contraction member) 40a. Is heated in two stages, and the other configurations are substantially the same as those shown in FIGS. 4 (a) to 4 (f). 7A to 7G, the same parts as those in FIGS. 4A to 4F are denoted by the same reference numerals, and detailed description thereof is omitted.

  First, a preform 10a made of a plastic material is prepared (see FIG. 7A).

  Next, a bottom protective member (outer shrink member) 40a made of polyolefin resin is provided on the outside of the preform 10a (see FIG. 7B).

  Next, the preform 10a and the bottom protection member (outer contraction member) 40a are heated by the first heating device 55 (see FIG. 7C). At this time, the heating temperature of the preform 10a and the bottom protection member (outer contraction member) 40a may be, for example, 50 ° C. to 100 ° C.

  When the bottom protection member (outer contraction member) 40a is heated, the bottom protection member (outer contraction member) 40a is thermally contracted and adheres to the outside of the preform 10a. As a result, a composite preform 70 having the preform 10a and the bottom protective member (outer contraction member) 40a in close contact with the outside of the preform 10a is obtained (see FIG. 7C).

  As described above, the composite preform 70 is manufactured by previously bringing the bottom protective member (outer contraction member) 40a into heat contact with the outside of the preform 10a by using the first heating device 55, thereby preparing the composite preform 70. A series of steps (FIGS. 7 (a) to (c)) and a series of steps (FIGS. 7 (d) to (g)) for producing the composite container 10A by blow molding are performed at different locations (factory etc. ) Can be implemented.

  Next, the composite preform 70 is heated by the second heating device 51 (see FIG. 7D). At this time, the composite preform 70 is evenly heated in the circumferential direction by the second heating device 51 while rotating with the mouth portion 11a facing downward. The heating temperature of the preform 10a and the bottom protection member (outer contraction member) 40a in this heating step may be, for example, 90 ° C. to 130 ° C.

  Subsequently, the composite preform 70 heated by the second heating device 51 is sent to the blow molding die 50 (see FIG. 7E). In this case, the heating for shrinking the bottom protective member (outer shrinking member) 40a and the heating for blow-molding the preform 10a can be performed in the same process.

  The composite preform 70 is molded using the blow mold 50, and is provided on the container body 10 and the outer surface of the container body 10 in substantially the same manner as in the case of FIGS. 4 (a) to 4 (f) described above. The composite container 10A provided with the bottom protecting member (outer contraction member) 40 is obtained (see FIGS. 7E to 7G). Thereafter, the composite container 10A is filled with the content L, and the cap 18 is attached to the mouth portion 11, whereby the content container 10B is obtained. Since the steps after FIG. 7G are the same as those shown in FIGS. 5A to 5C described above, detailed description thereof is omitted here.

  As described above, according to the present embodiment, the bottom protection member 40 is provided so as to cover at least the bottom 30 of the container body 10. Thus, even when the composite container 10A comes into contact with the lubricant G on the transport device 65, the bottom protection member 40 protects the bottom 30 of the container body 10, and thus the lubricant G adheres directly to the container body 10. There is nothing to do. As a result, the environmental stress fracture resistance (ESCR) of the container main body 10 is enhanced, and for example, even when stress is applied to the bottom 30 during storage of the composite container 10A, stress cracks are prevented from occurring in the bottom 30.

  In addition, according to the present embodiment, the same preform 10a as the conventional one can be used, so that a new injection mold for the preform 10a is produced, or the material of the preform 10a is changed. There is no need to do. For this reason, the environmental stress fracture resistance (ESCR) of the bottom part 30 of the container main body 10 can be improved by a simple method.

DESCRIPTION OF SYMBOLS 10 Container main body 10A Composite container 10a Preform 11, 11a Mouth part 12 Shoulder part 13 Neck part 14 Screw part 17 Flange part 20, 20a Body part 30, 30a Bottom part 31 Recessed part 32 Grounding part 40, 40a Bottom part protection part 41 Body part 42 Bottom part 50 Blow mold 70 Composite preform

Claims (10)

In the manufacturing method of the composite container,
Preparing a preform made of plastic material;
Outside the preform, the steps it mounted without bonding the polyolefin down resins made bottom protection member having formed in advance cylindrical portion,
A step of performing blow molding on the preform and the bottom protection member to expand the preform and the bottom protection member as a unit, and
The preform includes a mouth portion, a trunk portion, and a bottom portion, and the bottom protection member is provided so as to cover at least the bottom portion of the preform. It said bottom protective member, the manufacturing method of the composite container according to claim 1, characterized in that it comprises a polyethylene emissions resins or polypropylene down resins. The method for manufacturing a composite container according to claim 1, wherein the bottom protective member is made of a heat-shrinkable material . In composite preform,
A preform made of plastic material,
The outside of the preform, and a polyolefin down resins made bottom protection member having a loaded pre cylindrical shape portion formed without being adhered,
The preform has a mouth portion, a trunk portion, and a bottom portion, and the bottom protection member is provided so as to cover at least the bottom portion of the preform. It said bottom protective member, the composite preform according to claim 4, characterized in that it comprises a polyethylene emissions resins or polypropylene down resins. The composite preform according to claim 4, wherein the bottom protective member is made of a heat-shrinkable material . In composite containers,
A container body made of plastic material;
And a polyolefin down resins made bottom protection member provided in close contact without being bonded to the outside of the container body,
The container body and the bottom protection member are integrally blow-molded products that are in an inflated state by blow molding ,
The said container main body has a mouth part, a trunk | drum, and a bottom part, and the said bottom part protection member is provided so that at least the said bottom part of the said container main body may be covered. It said bottom protective member, composite container according to claim 7, characterized in that it comprises a polyethylene emissions resins or polypropylene down resins. The composite container according to claim 7 or 8, wherein the bottom protective member is made of a heat-shrinkable material . A composite having the preform and a bottom protective member in close contact with the outside of the preform by being mounted without being bonded to the outside of the preform made of plastic material and being expanded together with the preform. A bottom protecting member for producing a container,
It consists of polyolefin down resins,
A bottom portion protection member having a bottom portion covering at least the bottom portion of the preform.

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