JP2019072902A - Preform, plastic bottle and method for producing the same - Google Patents

Abstract

To provide a plastic bottle that has a mouth part having heat resistance or the like, without using crystallization, and a preform, and a method for producing a preform.SOLUTION: A preform 1 has a mouth part 10, a trunk part 16, and a bottom part 17, sequentially in the axial direction. The mouth part 10 has an intermediate layer. The intermediate layer 20 is between an outer layer 18a and an inner layer 19a, and the intermediate layer 20a has heat resistance or the like.SELECTED DRAWING: Figure 1

Description

  The present invention relates to preforms, plastic bottles and methods of making preforms, and more particularly, to multilayer plastic bottles, preforms and methods of making preforms.

  Plastic bottles, in particular, PET (PolyEthylene Terephthalate) bottles are often used as containers filled with beverages and the like. And the multilayer bottle on which another material is laminated to compensate for the function which is lacking in the polyethylene terephthalate of the base material of the PET bottle is also showing the market spread.

  Patent Document 1 has an inner and outer layer composed of an ethylene terephthalate based polyester resin, and at least one intermediate layer composed of at least a low crystalline ethylene terephthalate based polyester resin and an aromatic polyamide based gas barrier resin, and a low crystalline ethylene terephthalate. A multilayer preform is disclosed in which the polyester resin contains 7.5 to 15 mol% of isophthalic acid in the dicarboxylic acid component, and the haze of the portion where the multilayer structure is formed is 5% or more. Further, Patent Document 1 discloses a multilayer stretch blow molded container which is formed by biaxial stretch blow molding of a multilayer preform and the haze of the body portion is 3% or less.

JP, 2015-157469, A Japanese Examined Patent Publication 3-67499 Japanese Examined Patent Publication 4-13216 Patent No. 5289699 gazette

  According to Patent Document 1, by forming the inner and outer layers from a crystalline ethylene terephthalate-based polyester resin, it is possible to give a uniform draw ratio to an intermediate layer using a low crystalline polyester resin inferior in drawing characteristics. It is said that a multilayer stretch blow molded container having excellent mechanical strength can be provided. Furthermore, according to Patent Document 1, the inner / outer layer and the barrier intermediate layer are formed by forming a sea-island dispersion structure in which the barrier intermediate layer is a low-crystalline polyester resin continuous phase and the aromatic polyamide resin gas barrier resin is a dispersed phase. Interlaminar adhesion can be improved. And it is supposed that the multilayer stretch blow container obtained from the multilayer preform of patent document 1 can also prevent the delamination (delamination) etc. by a drop impact etc.

  In Patent Document 1, in order to secure the gas barrier properties of the container, it is necessary to form a barrier intermediate layer at least in a portion to be a container body of a multilayer preform which is drawn at a high magnification during drawing. There is a statement that there is. However, Patent Document 1 does not describe a configuration in which an intermediate layer using a heat-resistant material is formed in a portion to be a mouth of a container.

  In Patent Document 2, as a method of crystallizing the opening of the container made of polyethylene terephthalate resin by heating, whitening treatment is divided into the upper part of the opening and the side part of the opening, and the upper part of the opening is A whitening method for the mouth of a container made of polyethylene terephthalate resin is disclosed, which whitens the mouth side after whitening.

  Patent Document 3 also provides a crystalline thermoplastic polymer container that maintains its shape for a long time and retains its strength characteristics even when heated or pressurized to very high temperatures. It is made of a plastic polyester resin and has a mouth followed by a neck, a body and a bottom, and at least the body is oriented by biaxial stretching to be transparent and relieve internal stress, and the mouth is substantially Disclosed is a reinforced heat-resistant container characterized by being non-oriented crystallized and milky whitened.

Patent Document 4 discloses a plastic container which can be sealed by attaching a screw-on cap having an outer ring, a contact ring and an inner ring to an opening, and the opening is a plastic container which is not subjected to a crystallization treatment. There,
A screw is formed on the outer periphery of the mouth,
It is a plastic container provided with an undercut portion in which the outer diameter increases in a curved shape as it approaches the top surface at least at a part between the screw upper end and the top surface of the opening.
An outer ring contact portion which is a contact portion between the screw upper end of the opening and the top surface of the opening, which is a contact portion with the outer ring of the cap, (b) the opening A contact ring contact portion which is a contact portion between a top surface of the portion and a contact ring of the cap, and (c) an inner ring contact portion which is a contact portion between the inner side of the mouth portion and an inner ring of the cap A plastic container is disclosed, characterized in that it is realized by the close contact between the and the cap.

  In the first place, conventionally, the plug part is made to have heat resistance by crystallizing the plug part of the conventional plastic bottle container as described above. Conventionally, the method of sterilizing by heating the beverage at high temperature and filling it is well performed, and it is said that the plug part is likely to be at high temperature and easily deformed because it is filled with the beverage or liquid that is at a higher temperature than the mouth. There is a problem that causes crystallization of the plug. By crystallizing the mouth, the plastic bottle after molding has heat resistance, is less likely to be deformed, and there is no advantage that the engagement with the cap does not deteriorate, so that there is an advantage that liquid leakage and the like are less likely to occur. is there. However, in order to crystallize the mouth, for example, as in Patent Document 2, in order to crystallize the mouth of the polyethylene terephthalate resin container by heat treatment, the upper portion and the side portion of the mouth are divided. In addition, a technique for whitening treatment is required, and blow molding is required using a method such as that disclosed in Patent Document 3. Moreover, even if such a method is used, there is a problem that the cost for producing a plastic bottle container or the like having a crystallized mouth portion is considerably large.

  Therefore, in order to ensure the adhesion of the cap without crystallization of the opening, a screw is formed on the outer periphery of the opening as in Patent Document 4, and at least between the upper end of the screw and the top surface of the opening. By providing an undercut portion in which the outer diameter increases in part as it approaches the top surface, a method has been devised in which the sealing performance can be maintained even when receiving an impact such as a temperature change or a drop. Since such techniques and molding are required, it is necessary to prevent deformation of the mouth itself, to more easily improve the adhesion of the cap, and to prevent liquid leakage.

  Therefore, an object of the present invention is to provide a preform that can be made resistant to deformation and to have heat resistance regardless of crystallization at a low cost, a method for manufacturing the preform, and the preform Providing a plastic bottle formed by blow molding.

  In order to solve the above problems, the present invention provides a multilayer preform having an opening, a body, a bottom, and an annular support ring projecting outward from the opening, the intermediate layer being the opening The part is surrounded by the base material layer and provided continuously.

  Further, the intermediate layer is made of a heat-resistant material.

  Further, the intermediate layer is provided between a position separated by 1 mm from the top surface of the mouth toward the bottom and a position separated by 3 mm from the support ring toward the bottom. It is characterized by

  Further, the intermediate layer is characterized in that the intermediate layer is continuously provided from a position 3 mm apart from the top surface toward the bottom and a position 4 mm apart from the support ring toward the bottom.

  Furthermore, the weight of the intermediate layer is 1.5 to 3 weight percent with respect to the weight of the entire preform.

  Furthermore, the present invention relates to a method for producing a preform according to the present invention, wherein the first molding material is injected at the start of injection in the method for producing a preform by coinjection molding in which one material is injected and the other material is injected. The second molding material is injected all the time from the end of the injection, the second molding material is sandwiched by the first molding material at the same time as the injection start, and the injection is started, and the injection amount of the second material is It is characterized in that the injection of the second material is ended when reaching 1.5% by weight to 3% by weight with respect to the whole of the reform.

  Furthermore, the present invention relates to a method for producing a preform according to the present invention, wherein the first molding material is injected in the method for producing a preform by co-injection molding in which one material is injected and the other material is injected. The injection is started all the way from the start to the end of the injection, the injection of the second molding material is started immediately after the start of the injection, and the injection amount of the second material is 1. for the entire preform. The injection of the second material is terminated when reaching 5 weight percent to 3 weight percent.

  Further, the present invention provides a plastic bottle characterized in that the above-described preform is formed by blow molding.

  According to the present invention, in the preform having a multilayer structure having an opening, a body, a bottom, and an annular support ring projecting outward from the opening, the intermediate layer is surrounded by the base layer at the opening. Since the present invention is characterized by being continuously provided, by using a special material for the mouth, it is possible to provide a preform having various functions. In addition, as described later, the mouth portion has a configuration in which an intermediate layer is provided only in a portion which is not stretched in a process of forming into a plastic bottle later. As described above, since the intermediate layer has a configuration in which the intermediate layer does not protrude into the stretchable portion of the plastic bottle or the like after blow molding, an excellent preform is provided which is less likely to be deformed due to the deviation of the material during stretching. be able to.

  Further, since the intermediate layer is made of a heat-resistant material, the mouth can be heat-resistant even if the mouth is not crystallized. By having such a configuration, when heat is applied to the mouth, for example, when high temperature liquid is poured from the mouth by sterilization or injection of a beverage, heat is applied regardless of crystallization. It can have a function to prevent it from being deformed. Then, when a beverage or the like is accommodated in a plastic bottle molded from a preform by a known method, if the liquid is deformed by the application of heat, the accommodated liquid may leak. By having the above configuration, even if it is not due to crystallization, it is possible to prevent deformation due to the application of heat, and liquid leakage can be prevented at low cost.

  Furthermore, since the intermediate layer is provided from a position separated by 1 mm from the top surface of the mouth toward the bottom, and a position separated by 3 mm from the support ring toward the bottom from the support ring It is possible to give the mouth a strong heat resistance without depending on crystallization. By having heat resistance, it is possible to prevent liquid leakage when molded into a plastic bottle. In addition to this, the part to which the intermediate layer stretches when blow-molded into a plastic bottle will not have the intermediate layer. Therefore, it is possible to provide an excellent preform which is not easily deformed when blow molding.

Furthermore, by having such a configuration, the intermediate layer is not exposed on the oral cavity surface. In other words, the oral cavity surface is covered with the base material layer, and the intermediate layer is provided from the position 1 mm away from the oral cavity surface toward the bottom. By having such a configuration, when the preform of the present invention is molded into a plastic bottle, a safe plastic bottle for beverage can be obtained.
Further, by covering the oral cavity surface with the base material layer, peeling of the base material layer and the intermediate layer can be prevented more than in the case where the intermediate layer is exposed to the oral cavity surface. In the case where exfoliation occurs in the mouth due to an impact or the like on the mouth, for example, when the preform of the present invention is used for a plastic pet bottle, the mouth and the mouth of a person are in contact. From this, by making the base material layer cover the oral cavity surface, it is possible to provide a preform that is the basis of a plastic bottle with higher safety.

  Furthermore, more preferably, the intermediate layer is provided continuously from a position separated by 3 mm from the mouth top surface toward the bottom portion, and a position separated by 4 mm from the support ring toward the bottom portion. Because of this, it is possible to provide the mouth with heat resistance of further strength. In addition, by having heat resistance, it is possible to further prevent liquid leakage when molded into a plastic bottle. In addition, when the preform is blow-molded into a plastic bottle, there is a portion where the intermediate layer is stretched by blow molding. The above configuration is configured such that the intermediate layer does not exist in this portion. As described above, since the intermediate layer has a configuration in which the intermediate layer does not protrude into the stretchable portion of the plastic bottle or the like after blow molding, an excellent preform is provided which is less likely to be deformed due to the deviation of the material during stretching. be able to.

  Furthermore, according to a configuration in which the weight of the intermediate layer is 1.5% by weight to 3% by weight with respect to the entire preform, by providing the intermediate layer using a heat-resistant material in the opening, heat resistance is applied to the opening It is possible to provide a preform which is a base of a plastic bottle having a small amount of heat-resistant material in the middle layer and having excellent recyclability while maintaining the property.

Furthermore, according to the manufacturing method of the present invention, in the method for manufacturing a preform by coinjection molding in which one material is injected and the other material is injected, the first molding material is injected all the time from the injection start time to the injection end time. The second molding material is sandwiched by the first molding material substantially simultaneously with the start of the injection and injection is started, and the injection amount of the second material is 1.5 weight to the whole preform. The injection of the second material is terminated when reaching a percentage to 3 weight percent. By this method, efficient production of the preform of the present invention can be performed.
Furthermore, according to the present invention, in a method of manufacturing a preform by coinjection molding in which one material is injected and the other material is injected, the first molding material is injected all the time from the injection start time to the injection end time. The second molding material is injected immediately after the start of the injection, and when the injection amount of the second material reaches 1.5% by weight to 3% by weight with respect to the whole preform, the second molding material It is characterized by terminating the injection of the material. By this method, it is possible to manufacture a safe preform in which the intermediate layer is not exposed on the oral cavity surface.

  Furthermore, by molding the preform of the present invention, it is possible to provide an excellent plastic bottle with high safety and less deformation and liquid leakage from the mouth.

It is a sectional view in which an example of a preform concerning this embodiment was shown. FIG. 2 is a cross-sectional view schematically showing a hot runner nozzle of an injection molding apparatus as an example of a preform manufacturing apparatus. It is the graph in which the relationship of the injection rate and time of each molding material co-injected was shown typically. It is sectional drawing in which the outline of the state (step S1) of each molding material flowing from a hot runner nozzle to a cavity was shown. It is sectional drawing in which the outline of the state (step S3) of each molding material flowing from a hot runner nozzle to a cavity was shown. It is sectional drawing in which the outline of the state (step S4) of each molding material flowing from a hot runner nozzle to a cavity was shown. It is sectional drawing in which the outline of the state (step S7) of each molding material flowing from a hot runner nozzle to a cavity was shown. It is sectional drawing in which an example of the heating apparatus of preform was shown. It is sectional drawing with which the preform and the PET bottle after blow molding were shown typically. It is the front view in which the PET bottle formed from the preform concerning this embodiment was shown. It is sectional drawing of the PET bottle of FIG. It is the perspective view seen from the bottom side of the PET bottle of FIG.

  Hereinafter, the details of the embodiments of the present invention will be described with reference to the drawings. First, the configuration of a preform 1 (preformed body) for forming a PET (PolyEthylene Terephthalate: polyethylene terephthalate) bottle according to the present embodiment will be described in detail. FIG. 1 is a cross-sectional view showing an example of a preform 1 according to the present embodiment. The preform 1 has a bottomed cylindrical shape, and the mouth 10, the body 16, and the bottom 17 are sequentially provided in the axial direction. The preform 1 is formed into a bottle by drawing. At this time, it is preferable to use a known blow molding technique. In FIG. 1, a plane in which the opening 10 to the bottom 17 are cut at the center of the preform 1 parallel to the axial direction is shown.

  In the following, for convenience of explanation, in the preform 1 in the state of FIG. 1, the direction of the opening 10 with respect to the bottom 17 is set to the upper side.

  The mouth 10 has an opening 11 that is circularly opened at the upper end in the axial direction. The opening 11 has an annular mouth surface 15 and a circular hole 11 a. The mouth 10 has an external thread 12, a cover 13 and a support ring 14 on the outer peripheral surface thereof. An external thread 12 for attaching a lid (not shown) projects from the outer peripheral surface of the opening 10 in a spiral manner outward in the radial direction of the preform 1. The hollows 13 project radially outward in the circumferential direction below the external threads 12. The support ring 14 projects radially outward of the bladder 13 in an encircling manner below the bladder 13.

  In general, at the upper portion in the axial direction from the support ring 14, the shape does not change when it is formed into a bottle shape from the preform 1. On the other hand, even in the range of up to 10 mm below the support ring 14, it is hardly stretched when it is formed into a bottle shape. Therefore, in this case, a range in which the shape hardly changes when molded into a bottle shape from the preform 1 is defined as the mouth portion 10. And, as exemplified in FIG. 1, the opening 10 has a substantially true cylindrical shape whose inner diameter and outer diameter are substantially the same size at the upper and lower sides in the axial direction at a position axially lower than the support ring 14 Also good.

  Thus, the shape of the opening 10 does not change even after molding by the blow molding machine. Here, there are no particular limitations on the dimensions of each part such as the inner diameter and the outer diameter (corresponding to the thread valley diameter) of the opening 10 of the preform 1 and the thread diameter. However, it is preferable that the dimensions generally used in a beverage bottle be adopted in terms of the versatility of the existing lid and the sealing performance of the beverage bottle. For this reason, for example, the opening 10 may be dimensioned in accordance with the PCO 1810 standard or the PCO 1881 standard.

  The body portion 16 has an inner diameter and an outer diameter that are substantially in the form of a substantially cylindrical shape having substantially the same size in the axial direction. However, the body portion 16 may be provided with a draft which is a slope for facilitating removal from the mold used in production of the preform 1, that is, release. Furthermore, the inner diameter and the outer diameter of the body portion 16 may slightly change in the axial direction. Furthermore, in particular, the outer diameter of the body portion 16 can be configured to be substantially equal at the upper and lower sides in the axial direction.

  The bottom portion 17 is configured in a substantially hemispherical shape curved outward. The bottom portion 17 may have a conical shape, a cylindrical shape with rounded corners, or any other shape.

  In addition, it is preferable that the outer diameter of the trunk | drum 16 is 12 mm or more and 30 mm or less from the point which can use the existing apparatus. Furthermore, it is preferable that the length from the lower surface of the support ring 14 to the lower end of the bottom 17 be 35 mm or more and 105 mm or less, because an existing apparatus, particularly a blow molding machine, can be used.

  In the preform 1, the mouth portion 10 is configured in multiple layers, and has an intermediate layer 20 a between the outer layer 18 a and the inner layer 19 a. The preform 1 illustrated in FIG. 1 has an intermediate layer 20 a from the upper end of the external thread 12 to the lower end of the opening 10. On the other hand, the body portion 16 and the bottom portion 17 do not have the intermediate layer 20a. As described above, by providing the middle layer only in the mouth, the mouth can have a special function. The body portion 16 and the bottom portion 17 do not have the intermediate layer 20a in the preform 1 illustrated in FIG. However, for example, an intermediate layer having excellent barrier properties may be provided on the body portion 16 or the bottom portion 17 or the like. Thereby, it can be set as the preform 1 which has the further multifunctionality.

  The preform 1 does not have an adhesive layer or an adhesive between the intermediate layer 20a and each of the outer layer 18a and the inner layer 19a. For this reason, preform 1 is not prevented from being recycled after use. On the other hand, since the layers are not firmly bonded, delamination may occur due to an external force. Therefore, the intermediate layer 20a is configured not to extend to the end of the opening 10, so that the end of the interface of each layer that is likely to be a starting point of breakage is not exposed at the opening surface 15 and delamination is less likely to occur. . However, in order to facilitate manufacture, the end of the interface of each layer may be exposed at the mouth surface 15.

  In the preform 1, as illustrated in FIG. 1, an intermediate layer 20 a is provided continuously from the upper end to the lower end of the mouth 10. At this time, it is preferable that the end of the intermediate layer 20 a be provided with the so-called screw start position, which is the upper end of the male screw 12, as the upper end. Then, the intermediate layer 20a is provided with the screw start position as the upper end, and since the intermediate layer is made of a heat-resistant material as described, the engagement of the screws does not shift.

  As illustrated in FIG. 1, the intermediate layer 20 a is provided in the range up to the lower end of the opening 10. By providing an intermediate layer using a heat-resistant material in the range of the opening 10, the intermediate layer is provided only on the portion that is not stretched when it is formed into a plastic bottle by blow molding later. Thereby, the extending | stretching part of the trunk | drum 16 can be made that it does not have an intermediate | middle layer, as illustrated in FIG. In the case where the intermediate layer in the present disclosure is provided so as to protrude to the body portion 16, it is likely to lose its shape in manufacturing. Therefore, the structure which does not have the intermediate | middle layer 20a in the trunk | drum 16 is excellent. However, the provision of the intermediate layer 20 a here only in the mouth 10 does not exclude the provision of separate intermediate layers on the trunk 16 and the bottom 17 of the separate intermediate layers.

  The thickness of the intermediate layer 20a is provided uniformly. By providing uniformly, even when heat is added and the base material layer is deformed, distortion is less likely to occur. However, in the base material layer of the support ring 14 of the mouth 10, the intermediate layer 20 a may be provided so as to protrude in the radial direction from the mouth 10. In this way, the preform 1 can be easily manufactured. As for the configuration of the opening 10, the intermediate layer is provided to protrude into the base material layer of the support ring 14 like a flange surrounded by the base material layer, and the thickness of the intermediate layer 20a in the other part is uniform. It may have the composition of being.

  It is preferable that the value which remove | divided the weight of the intermediate | middle layer 20a from the whole weight of the intermediate | middle layer 20a is 1.5 weight%-3 weight% in the preform 1 for 280 ml PET bottles. Thereby, the recyclability of the plastic bottle 2 which shape | molded the preform 1 by blow molding etc. improves. Although this ratio may vary depending on the size of the plastic bottle, this ratio corresponds to 5 to 10 weight percent as a ratio to the weight of the mouth. Also for 2 liter plastic bottles, if it is 3 weight percent, there is no difference from the above-mentioned preform 1 for a 280 ml plastic bottle as recyclability.

  For the intermediate layer 20a, materials exhibiting various functions can be selected. For example, the intermediate layer 20a may be made of a material that provides a light shielding property such as ultraviolet light and a gas barrier property such as water vapor. It is preferable to use a heat-resistant material for the intermediate layer 20a here. Here, the heat-resistant material may be a heat-resistant substance such as polyarylate or nylon, or polyarylate. Thermoplastic polyester resins having excellent heat resistance can also be used in the heat-resistant material of the present invention.

  As materials for the outer layer 18a and the inner layer 19a of the base layer 20 of the illustrated preform 1, polyolefins such as high density polyethylene, medium density polyethylene, low density polyethylene, linear low density polyethylene, polypropylene and the like, ethylene-vinyl It is possible to use various thermoplastic resins that can be blow-molded, such as alcohol copolymers, polylactic acid using plants and the like as raw materials. However, it is preferable that the outer layer 18a and the inner layer 19a be a PET layer whose main component is polyester such as polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyarylate, and the like, in particular polyethylene terephthalate. In the resin mentioned above, various additives such as a coloring agent, an ultraviolet absorber, a releasing agent, a lubricant, a nucleating agent, an antioxidant, and an antistatic agent are blended so long as the quality of the molded product is not impaired. be able to.

  The ethylene terephthalate-based thermoplastic resin constituting the outer layer 18a and the inner layer 19a of the preform 1 is such that the ethylene terephthalate unit occupies most of the ester repeating portion, generally 70 mol% or more, and the glass transition point (Tg) Is preferably 50 ° C. or more and 90 ° C. or less, and the melting point (Tm) is preferably 200 ° C. or more and 275 ° C. or less. Although polyethylene terephthalate is particularly excellent in terms of pressure resistance and the like as an ethylene terephthalate thermoplastic polyester, it is composed of isophthalic acid, a dibasic acid such as naphthalene dicarboxylic acid, and a diol such as propylene glycol in addition to ethylene terephthalate units. Copolyesters containing small amounts of ester units can also be used.

  Among the thermoplastic synthetic resins, polyethylene terephthalate produces the largest amount. The polyethylene terephthalate resin has various properties such as excellent heat resistance, cold resistance, chemical resistance, and abrasion resistance. Furthermore, the proportion of petroleum in the raw material of polyethylene terephthalate resin is lower than that of other plastics, and recycling is also possible. Thus, according to the structure which has a polyethylene terephthalate as a main component, material with a large amount of production can be used, and the various excellent characteristics can be utilized.

  Polyethylene terephthalate is obtained by condensation polymerization of ethylene glycol (ethane-1,2-diol) and purified terephthalic acid. It is preferable to use at least one of a germanium compound, a titanium compound, and an aluminum compound as a polymerization catalyst for polyethylene terephthalate. By using these catalysts, it is possible to form a container having higher transparency and superior heat resistance than the case of using an antimony compound.

  If the amount of the middle layer 20a relative to the entire preform 1 is too large, recycling after use of the preform 1 is hindered. On the other hand, if the amount of the intermediate layer 20a with respect to the entire preform 1 is too small, injection moldability will be reduced. More specifically, the intermediate layer 20a is difficult to be filled when the preform 1 is formed, and if it is forced in, the deterioration and uneven thickness occur, which is not preferable. Therefore, the proportion of the mid layer 20a in the entire preform 1 is required to be at least 0.5% by weight or more. Furthermore, it is preferable that it is 1.5 weight percent to 3 weight percent.

  The intermediate layer 20a is not limited to a single layer, and may be a multilayer. For example, in addition to the heat-resistant layer using a heat-resistant material, a plurality of oxygen barrier layers may be included. For example, the preform 1 may have a five-layer structure (PET layer (outer layer 18a) / oxygen barrier layer / heat-resistant layer / oxygen barrier layer / PET layer (inner layer 19a)). The number of layers in the middle layer 20a may be further increased, and the preform 1 may have a maximum seven-layer structure. By forming the intermediate layer 20a in multiple layers, the functions of the intermediate layer 20a can be further enhanced, and the intermediate layer 20a can be provided with a plurality of functions.

  In the method of manufacturing the preform 1 according to the present embodiment, the intermediate layer 20 a having a uniform thickness is formed in the base material layer of the opening 10. However, the intermediate layer 20 a may be formed to project into the support ring 14 of the mouth 10. According to the preform 1 manufactured in this manner, since the range of the intermediate layer remains in only the mouth portion 10 which is a non-stretched portion after the stretching of the intermediate layer 20 a Can be prevented. Then, by providing the intermediate layer only in the opening, the heat resistance of the opening 10 can be secured, and the amount of the molding material of the intermediate layer 20a can be reduced, thereby facilitating recycling.

  Then, next, an example of a manufacturing method of preform 1 is explained in detail. FIG. 2 is a cross-sectional view schematically showing a hot runner nozzle 31 of an injection molding apparatus 30 as an example of a manufacturing apparatus of the preform 1. The injection molding apparatus 30 includes a heating cylinder (not shown) including a screw therein, a hot runner nozzle 31, and a mold 32. The injection molding apparatus 30 is configured such that the molding material is melt-plasticized by heating to, for example, 270 ° C. to 300 ° C. by a heating cylinder, and is delivered to the mold 32 by the screw through the hot runner nozzle 31. It is done.

  The hot runner nozzle 31 is axially long. The hot runner nozzle 31 has a linear flow passage 33a, a first cylindrical flow passage 33b, a second cylindrical flow passage 34, and a check valve 35 which is an example of an on-off valve. Each flow path extends substantially in the axial direction. The hot runner nozzle 31 further comprises a first inlet 36, a second inlet 37 and an outlet 38.

  The injection port 38 is formed at the center of one end of the hot runner nozzle 31. The injection port 38 is in communication with the mold 32. On the other hand, the first inlet 36 and the second inlet 37 are formed on the side surface of the hot runner nozzle 31 near the other end. And each of the 1st injection port 36 and the 2nd injection port 37 is connected with a separate heating cylinder. That is, the hot runner nozzle 31 is configured to be able to inject the first molding material and the second molding material from the first injection port 36 and the second injection port 37, respectively. The molding material flows from the first inlet 36 and the second inlet 37 toward the outlet 38. For this reason, the other end of the hot runner nozzle 31 shown on the lower side in FIG. 1 is the upstream side of the molding material.

  The linear flow passage 33 a communicates with the flow passage extending in the radial direction from the first injection port 36, and linearly extends from the central portion of the hot runner nozzle 31 to the injection opening 38. The first cylindrical flow passage 33b is branched from the linear flow passage 33a, passes radially outward of the linear flow passage 33a, and is linear flow passage 33a at a first junction point 39a near the injection port 38. It joins with. The second cylindrical flow passage 34 communicates with the flow passage extending in the radial direction from the second inlet 37, and extends between the linear flow passage 33a and the first cylindrical flow passage 33b. And the straight flow path 33a at a second joining point 39b upstream of the joining point 39a.

  The hot runner nozzle 31 has a check valve 35 that closes the second cylindrical flow passage 34 at the second junction 39b. The check valve 35 responds to the difference in injection pressure between the first molding material passing through the linear flow passage 33a at the second junction 39b and the second molding material passing through the second cylindrical flow passage 34. And is configured to move in an axial direction. The check valve 35 is configured to open the second cylindrical flow passage 34 when the injection pressure of the second molding material is high. The check valve 35 may have another configuration as long as it performs such an action.

  The mold 32 configured to be divided into a plurality of parts has a cavity 32 a which is an air gap having a shape corresponding to the preform 1 and a gate 32 b at a position corresponding to the bottom 17 of the preform 1. The cavity 32a is in communication with the outlet 38 of the hot runner nozzle 31 via the gate 32b. The mold 32 is provided with a heater (not shown) for heating the mold 32 and a cooler (not shown) for cooling the mold 32. The mold 32 is configured such that the molten molding material is injected into the cavity 32a heated by the heater, and after being pressurized, the mold 32 is cooled by the cooler and the preform 1 is molded.

FIG. 3 is a graph schematically showing the relationship between injection rate and time of each molding material to be co-injected. The injection rate is indicated by the mass [g] of each molding material injected per unit time [s]. In FIG. 3, the first molding material is shown as a solid line and the second molding material is shown as a broken line. Here, polyethylene terephthalate (hereinafter referred to as PET resin a) is injected into the first molding material, and polyarylate (hereinafter referred to as heat resistant resin b) is injected into the second molding material. An example is shown where is injected. Then, for example, as shown in FIG. 3, in the method of manufacturing the preform 1, the step of injecting the first molding material (step S1), and the second molding material at an injection rate higher than the first molding material Injection step (step S4 to step S5) and a step of injecting the first molding material at a higher injection rate than the second molding material (step S5), and the injection rate higher than the first molding material The step of injecting the second material (step S4 to step S5) includes the step of gradually increasing the injection rate of the second molding material (step S4). And according to this method, the amount of the molding material of the intermediate layer 20a can be reduced while securing the function even after the intermediate layer 20a of the manufactured preform 1 is stretched.
By performing injection molding according to the injection timing of this figure, it is possible to form one form of the preform of the present invention in which the intermediate layer 20a is not exposed on the oral cavity surface.

  First, PET resin a is injected (step S1). FIG. 4 is a cross-sectional view schematically showing the molding materials flowing from the hot runner nozzle 31 to the cavity 32a (step S1). The PET resin a is fed from the first injection port 36 (see FIG. 2) via either the linear flow path 33a (PET resin a1) or the first cylindrical flow path 33b (PET resin a2). It joins at the first junction point 39a, and then flows in the order of the injection port 38 and the gate 32b to be filled in the cavity 32a. As exemplified in FIG. 4, the flow of the PET resin a through each of the linear flow path 33a (PET resin a1) and the first cylindrical flow path 33b (PET resin a2) is the PET resin layer A1, And it comprises PET resin layer A2, and it is filled with cavity 32a as PET resin layer A. As shown in FIG.

  At this stage, the heat-resistant resin b is not injected, and the second cylindrical flow path 34 is closed by the check valve 35 that receives the injection pressure of the PET resin a1.

  Next, the PET resin a1 is lowered to a predetermined injection rate and injected (step S2). The lowered injection rate is determined in balance with the injection rate of the heat resistant resin b injected in the next stage. Here, also in step S1, if PET resin a is injected at this previously lowered injection rate, if there is no dimensional defect in the mouth 10 or poor shaping such as sink marks, step S2 is omitted. It is good.

  Next, the heat resistant resin b is injected at an injection rate higher than that of the PET resin a1 (step S3). FIG. 5 is a cross-sectional view schematically showing the molding materials flowing from the hot runner nozzle 31 to the cavity 32a (step S3). The pressure at which the heat resistant resin b is injected moves the check valve 35, and the second cylindrical flow path 34 is opened. Then, as illustrated in FIG. 5, the heat resistant resin layer B is formed between the PET resin layer A1 passing through the linear flow passage 33a and the PET resin layer A2 passing through the first cylindrical flow passage 33b. It is formed. The heat-resistant resin layer B flows at a higher speed than the PET resin layers A1 and A2 because the heat-resistant resin layer B flows without being in contact with the molding die and the temperature does not decrease and the viscosity does not increase.

  Next, the heat-resistant resin b is injected while maintaining the injection ratio of the same degree (step S4). FIG. 6 is a cross-sectional view schematically showing the molding materials flowing from the hot runner nozzle 31 to the cavity 32a (step S4).

  Next, injection is performed until the injection ratio of the heat resistant resin b gradually decreases and becomes zero, and injection is performed so that the injection ratio of the PET resin a gradually increases (step S5). After the injection ratio of the heat resistant resin b gradually decreases, the heat resistant resin layer B is injected so as to be gradually thinner and then it is interrupted. Then, when the injection rate of the heat resistant resin b becomes zero, the check valve 35 moves and the second cylindrical flow path 34 is closed.

  Next, the PET resin a is maintained at a predetermined injection rate and injected (step S6). FIG. 7 is a cross-sectional view schematically showing the molding material flowing from the hot runner nozzle 31 to the cavity 32a (step S6). As illustrated in FIG. 7, the heat-resistant resin layer B is pushed in by the PET resin layer A.

  Finally, the PET resin a is injected until the inside of the cavity 32a is filled (step S8). The injection rate of the PET resin a gradually decreases, and when the inside of the cavity 32a is filled, the injection rate of the PET resin a becomes zero, and thereafter, the pressure is held so that the PET resin a does not reversely flow. Then, after the molding material is cooled inside the cavity 32a, the mold 32 is opened, and the molded preform 1 is taken out.

  The pressure at which each molding material is injected and the injection ratio are appropriately designed according to the difference in viscosity and the like.

  As described above, the method for manufacturing the preform 1 according to the present embodiment is configured to include the procedure for uniformly molding the intermediate layer 20a.

  For example, in the apparatus for manufacturing preform 1, the hot runner nozzle 31 merges at a first junction point 39a after branching from the linear channel 33a extending from the first inlet 36 and the linear channel 33a. And a second junction upstream of the first junction point 39a and extending from the second inlet 33 to the linear passage 33a and the first cylindrical passage 33b. The second cylindrical channel 34 joining the straight channel 33a at the point 39b, and the first material and the second cylindrical channel 34 passing through the straight channel 33a at the second joining point 39b And a check valve 35 that opens the second cylindrical flow passage 34 in accordance with the difference in injection pressure with the passing second material, and the cavity 32 a corresponding to the preform 1 and the bottom 17 of the preform 1 And a mold 32 having a gate 32b at a position corresponding to And a hot runner nozzle 31 communicating with the gate 32b.

  The manufacturing method may be another method. For example, by plasticizing and extruding the PET resin a, the heat resistant resin b, and the PET resin a in this order, a molten resin block (billet) in which the heat resistant resin b is enclosed in a U shape is generated and compression molded. It may be a method by which the preform 1 is manufactured.

  The formed preform 1 may be boxed, so-called palletized and temporarily stored in a warehouse or the like, and may be advanced to the next step as it is. That is, so-called cold parison method (two-stage method) may be used, in which molding of preform 1 and blow molding are performed in different places and devices, and molding of preform 1 and blow molding are the same. It may be a so-called hot parison method (one-stage method) performed in a place or apparatus. Furthermore, the manufacturing process from the molding of the preform 1 to the filling of the contents and the like may be continuous in-line.

  Next, an example of a method of forming the preform 1 according to the present embodiment into a bottle shape will be described in detail. First, the preform 1 is heated when the preform 1 is formed into a bottle shape. FIG. 8 is a cross-sectional view showing an example of the heating device 40 of the preform 1. FIG. 8 shows a cross section perpendicular to the transport direction of the preform 1.

  The heating device 40 includes a transport device 41 and a heater 42. The conveying device 41 is configured to convey the preform 1 while rotating the preform 1 about its axis so as to uniformly heat the preform 1 in the circumferential direction. The heater 42 is constituted by a plurality of, for example, halogen lamps, and is configured to heat the preform 1 to a temperature suitable for blow molding, for example, 80 ° C. to 140 ° C. Furthermore, the heating device 40 includes a reflecting plate 43 for reflecting the heat from the heater 42 to the preform 1, a shielding member 44 for preventing the heat from the heater 42 from being dissipated to the outside of the heating device 40, etc. May be provided. In addition, in the heating apparatus 40 of FIG. 8, the preform 1 is conveyed and heated in the state which the opening part 10 turned downward.

The heated preform 1 is then formed into a plastic bottle, for example, a PET bottle 2 by a blow molding machine. FIG. 9 is a cross-sectional view schematically showing the preform 1 and the PET bottle 2 after blow molding. A biaxial stretch blow molding device 50 as an example of a blow molding machine includes a mold 51, a stretch rod 52, a high pressure air supply device (not shown), and a control device (not shown) for controlling them. Although a downward blow molding method is illustrated in FIG. 9, an upward blow molding method in which the material is less susceptible to gravity may be used.

  Here, the PET bottle 2 has an upper portion 30, a body portion 70 and a lower portion 80. The mouth 10 of the preform 1 corresponds to the upper portion 30 of the PET bottle 2 and the bottom 17 of the preform 1 corresponds to the lower portion 80 of the PET bottle 2 before and after blow molding.

  The mold 51 has a shape corresponding to the PET bottle 2 to be formed, and, for example, a body mold 51 a configured in half corresponding to the body 70 and a bottom mold corresponding to the lower portion 80 And 51b. The temperature of the surface of the mold 51 is controlled to be, for example, 30 ° C. to 130 ° C. depending on the use of the PET bottle 2, in particular, the heat resistance.

  The extension rod 52 is configured to be extensible and contractible in the mold 51. Then, the extension rod 52 is configured to extend the neck portion 15 and the body portion 16 of the preform 1 in which the mouth portion 10 is attached to the mold 51 in the longitudinal (axial) direction. The temperature-controlled high pressure air h is blown out from the high pressure air supply device. The high pressure air h may be supplied to the inside of the preform 1 attached to the mold 51, and may be blown out from the stretching rod 52 or may be blown out from a member other than the stretching rod 52. The high pressure air h is configured to extend the body portion 16 of the preform 1 in the lateral (diameter) direction and to lower the surface temperature of the body portion 16 after the extension.

  The heated preform 1 is mounted on the mold 51 of the biaxial stretch blow molding apparatus 50. Thereafter, the body portion 16 of the preform 1 mounted on the mold 51 is stretched in the longitudinal direction by the stretching rod 52. The longitudinal stretching ratio from the preform 1 to the PET bottle 2 at this time is preferably 1.8 times or more and 4.0 times or less.

  Here, the longitudinal stretching ratio is the ratio of the length from the lower surface of the support ring 14 of the PET bottle 2 to the lower end of the lower portion 80 to the length from the lower surface of the support ring 14 of the preform 1 to the lower end of the bottom 17. . The molecules of the preform 1 having an amorphous structure, which is an aggregate of an amorphous part and a crystalline part, undergo oriented crystallization due to stretching, and as a result, the strength, rigidity, heat resistance and the like of the PET bottle 2 increase. When the longitudinal stretching ratio is less than 1.8, the orientation of the molecules of the PET bottle 2 (preform 1) does not increase, while when the longitudinal stretching ratio is 4.1 or more, the PET bottle 2 is molded It becomes difficult.

  Further, the middle portion 16 of the longitudinally stretched preform 1 is stretched by the high pressure air h in the lateral direction until it hits the mold 51. It is preferable that the horizontal draw ratio from the preform 1 to the PET bottle 2 at this time is 1.5 times or more and 6.0 times or less.

  Here, the lateral stretching ratio is the ratio of the barrel diameter of the barrel 70 of the PET bottle 2 to the barrel diameter of the barrel middle portion 16 of the preform 1. The distance between the centers of thickness on the opposite wall surfaces of the body 70 is taken as the body diameter of the body 70. The molecules of the preform 1 are similarly oriented and crystallized by stretching in the lateral direction, and as a result, the strength, rigidity, heat resistance and the like of the PET bottle 2 are increased. When the transverse draw ratio is less than 1.5, the orientation of the molecules of the PET bottle 2 (preform 1) does not increase, while when the transverse draw ratio is 6.1 or more, the PET bottle 2 is molded It becomes difficult.

  Thus, in the molding by the biaxial stretch blow molding apparatus 50, the draw ratio in the longitudinal direction is 1.8 times or more and 4.0 times or less, and the draw ratio in the transverse direction is 1.5 times or more and 6.0 times or less According to the configuration of the biaxial stretch blow molding, the lightweight PET bottle 2 can be formed from the preform 1 with better blow moldability.

  As described above, in the PET bottle 2 according to the present embodiment, the preform 1 is formed into a bottle shape by the biaxial stretch blow molding apparatus 50. And, by using the biaxial stretch blow molding apparatus 50, it is possible to effectively form the lightweight PET bottle 2 with good blow moldability from the preform 1 according to the present embodiment.

  In the present embodiment, the application of the molded PET bottle 2 is not limited. Therefore, the PET bottle 2 may be molded to have pressure resistance, oxygen barrier properties, and the like.

  Next, the configuration of the PET bottle 2 formed from the preform 1 according to the present embodiment will be described in detail. FIG. 10 is a front view showing a PET bottle 2 formed from a preform 1 according to the present embodiment. The PET bottle 2 illustrated in FIG. 10 is a round bottle whose cross-sectional view in the direction perpendicular to the axial direction is substantially circular. As described above, the PET bottle 2 has an upper portion 30, a body 70 and a lower portion 80. And, as described above, the configuration of the upper portion 30 of the PET bottle 2 is the same as the configuration of the mouth portion 10 of the preform 1.

  The upper portion 30 is a filling port and a pouring port for contents, and the PET bottle 2 is sealed by attaching a lid (not shown) to the upper portion 30.

  The body 70 has a generally frusto-conical shape in which the portion adjacent to the upper portion is expanded in diameter from the upper side to the lower side. In the barrel, the portion between the generally frusto-conical shaped portion and the bottom has a cylindrical shape. The body 70 may have a pressure absorbing panel, a lateral groove, and a longitudinal groove.

  As shown in FIG. 12, the upper portion of the lower portion 80 continues to the lower side of the trunk 70. The lower portion 80 illustrated in FIG. 10 has a so-called petaloid shape. The lower portion 80 has a recess 81, a leg 82, a valley 83 and the like. The recess 81 located at the radial center of the lower portion 80 is configured to protrude toward the inside (axially upper side) of the PET bottle 2. The legs 82 extend radially outward from the recess 81 radially downward toward the axial direction. The legs 82 serve as the ground contact surface of the PET bottle 2. Valleys 83 are formed between the adjacent legs 82. The valley portion 83 extends radially outward and axially upward from the recess 81. The configuration of the lower portion 80 is not limited to the example shown in FIG. 10, and may have a shape corresponding to the contents, for example, a shape in which ribs are provided radially.

  FIG. 11 is a cross-sectional view of the PET bottle 2. Furthermore, in FIG. 11, the area A of the upper portion 30 is shown enlarged. The PET bottle 2 has a multi-layered upper portion 30 and an intermediate layer 20 between the outer layer 18 and the inner layer 19. Similar to the preform 1, in the PET bottle 2, the intermediate layer 20 is preferably configured in the base layer of the upper portion 10. At this time, when the upper end of the intermediate layer 20 is at or above the same position as the screw start position, the engagement between the cap and the screw does not deteriorate, which is preferable. In the configuration where the intermediate layer starts from 1 mm below the mouth top surface and the intermediate layer is 3 mm below the support ring, the intermediate layer is formed from above the screw start position, and in the case of the intermediate layer using a heat resistant resin The heat resistance of the mouth increases, which is preferable. However, considering the ease of drawing during molding, the formability starts better with an intermediate layer starting 3 mm below the mouth top and 3 mm below the support ring, with a short intermediate layer under the support ring. Therefore, it is more preferable.

  By providing the middle layer in the mouth, it is possible to obtain a preform capable of forming a plastic bottle in which liquid leakage is prevented, which is preferable.

  The type, material, amount, layer configuration and the like of the intermediate layer 20 are the same as those of the preform 1 described above.

  The shape of the PET bottle 2 particularly below the support ring 14 is not limited to the example shown in FIG. 10 or the like, and any shape may be used as long as it is formed by blow molding the preform 1 . For example, in the present embodiment, the round bottle shown in FIG. 10 can be suitably formed. However, the plastic bottle formed in the present embodiment is not limited to the round bottle, and may be a square bottle. Furthermore, the width of the trunk 70 may be expanded downward. Also, the shape of the pressure absorbing panel formed in the body portion 70, the lateral groove, and the longitudinal groove can be freely designed.

  The PET bottle 2 according to the present embodiment is not limited by the size, and can be applied to various sizes. For example, the volume of the PET bottle 2 may be 100 ml or more and 1000 ml or less, and in particular, it is suitable for the PET bottle 2 having a volume of 200 ml or more and 700 ml or less. The total height of the PET bottle 2 may be 120 mm or more and 260 mm or less, and the body diameter of the body 70 may be 40 mm or more and 75 mm or less.

  Furthermore, the PET bottle 2 according to the present embodiment can be suitably used for a lightweight bottle. The mass of the PET bottle 2 may be, for example, 12 g or more and less than 14 g for an internal volume of 200 ml and 13 g or more and less than 15 g for an internal volume of 550 ml. And, in particular, from the viewpoint of maintaining the strength of the PET bottle 2 while maintaining the function of the middle layer 20, having a lightweight property, the value of the ratio of the mass to the internal volume of the PET bottle 2 is 0.0125 g / ml or more It is preferable that it is 0.0700 g / ml or less.

  A plastic bottle can be produced by blow molding a preform 1 obtained by injection molding the above-described material. And by using polyethylene terephthalate as a material, PET bottle 2 as an example of a plastic bottle concerning this embodiment is produced. And a filling body is comprised by the PET bottle 2 and the liquid filled. The filling body is manufactured by being filled with a liquid such as a beverage or a seasoning from the upper portion 30 of the PET bottle 2 and sealed by a lid (not shown) attached to the upper portion 30.

  In addition, it is not limited about the filling method of the content to PET bottle 2 either. Therefore, the PET bottle 2 may be used for hot filling or for aseptic filling.

  As described above, the PET bottle 2 has the upper portion 30, the body portion 70, and the lower portion 80 sequentially in the axial direction, and the mouth portion 30 is configured in multiple layers to form the intermediate layer 20 between the outer layer 18 and the inner layer 19. Have. According to such a configuration, the amount of molding material of the intermediate layer 20 can be reduced while securing the function of the intermediate layer 20. Of course, as the molding material is reduced, another intermediate layer can be provided at another portion.

  Hereinafter, the present disclosure will be described in more detail and specifically by showing examples. However, the present disclosure is not limited to the following examples.

<Materials and manufacturing method>
Example 1
Polyethylene terephthalate (PET resin a) is used for the outer layer 18 and the inner layer 19, and polyare (heat-resistant resin b) is used for the intermediate layer 20, and the 22 g preform 1 is specified in FIG. Made by the method shown in the book. The proportion of the heat resistant resin b in the whole of the preform 1 was 3% by weight. The weight of the preform was 21.8 g.

  Then, from the preform 1, a PET bottle 2 having a full injection volume of 295 ml as shown in FIG. 10 and the like was produced by blow molding. LB01 was used for the blow molding machine. The PET bottle 2 was filled with 280 ml of water and then a lid was attached to make a filling body.

  The intermediate layer 20 of the preform 1 according to Example 1 had the features according to the present embodiment, such as being uniform in thickness, being surrounded by the base material layer in the mouth, and the like. The middle layer was continuously provided in the range of 3 mm below the support ring from a position of about 1 mm from the oral cavity surface.

Comparative Example 1
In Comparative Example 1, a single-layer preform was produced using only the PET resin a without using the heat-resistant resin b. The weight of the preform was 21.8 g. Then, a PET bottle 2 having a full injection volume of 295 ml as shown in FIG. 10 and the like was produced by blow molding. LB01 was used for the blow molding machine. The PET bottle 2 was filled with 280 ml of water and then a lid was attached to make a filling body.

<Evaluation method>
(Use of material of heat-resistant layer)
It was judged by the mass of the material of the heat-resistant layer used for each PET bottle of Example 1 and Comparative Example 1 whether or not the reduction of the usage could be achieved. In the determination of the reduction in the amount used, the proportion of the heat resistant resin b in the whole of each PET bottle (each preform) is more than 20 wt%, less than, and more than 5 wt%, or less It was set as a threshold. Table 1 shows the evaluation results of the reduction rate of the material usage of the heat-resistant layer in each PET bottle, ◎: extremely high reduction rate, :: high reduction rate, x: low reduction rate, It is written.

(Heat-resistant)
It was determined whether heat resistance could be sufficiently achieved in each of the plastic bottles of Example 1 and Comparative Example 1. For determination of heat resistance, each plastic bottle was filled with normal temperature water, the cap was closed, and stored at 70 ° C. for 1 week in a heat preservation cabinet. Thereafter, the dimensions of the plug portion were measured, and the amount of expansion change was compared. Table 2 summarizes it.

  The expansion variation of the thread diameter in Comparative Example 1 was measured to be 0.35 mm, the thread valley diameter was 0.14 mm, the support ring diameter was 0.76 mm, and the support ring lower diameter was 1.52 mm. On the other hand, in Example 1, the thread diameter was 0.09 mm, the thread valley diameter was 0.05 mm, the support ring diameter was 0.22 mm, and the support ring lower diameter was 0.35 mm. Therefore, Example 1 was considered to be superior to Comparative Example 1 as heat resistance.

(Comprehensive evaluation)
Based on the usage of the material of the heat-resistant layer mentioned above, and heat resistance, comprehensive evaluation of each PET bottle (each filling body) of Examples 1-3 and Comparative Examples 1-2 was made. Table 1 shows the results of the comprehensive evaluation. The overall evaluation is indicated by ◎: very good, :: good, x: no suitability.

  The heat resistance of Comparative Example 1 was insufficient. The heat resistance of Example 1 was also sufficient, and the results were good. Therefore, according to the results of the above-described examples, in the preform 1 and the PET bottle 2 (filler) according to the present embodiment, the intermediate layer is provided on the opening 10 and the upper portion 30, thereby providing heat resistance and It has been shown that the amount of material used for the heat resistant layer is reduced. Therefore, in this embodiment, a method of manufacturing the PET bottle 2, the preform 1, and the preform 1 in which the amount of the molding material of the intermediate layer 20 is reduced while the function of the intermediate layer 20 is secured is provided. It was shown that it was possible.

  The present disclosure can be suitably applied to various plastic bottles that are filled with liquid as a content. However, the present disclosure is not limited to the embodiments and examples described above. The plastic bottle of the present disclosure includes, for example, various non-carbonated beverages such as water, green tea, oolong tea, black tea, coffee, fruit juice, soft drinks, It is useful for containing foods, detergents, shampoos, cosmetics, medicines and any other contents. In addition, in the present disclosure, it is possible to perform high-temperature sterilization etc., in particular, without crystallization, and it is also useful for containing a hot drink and using it for sale using a hot warmer.

1 Preform 2 PET bottle (plastic bottle)
DESCRIPTION OF SYMBOLS 10 mouth part 14 support ring 15 mouth surface 16 body part 17 bottom part 18 outer layer of PET bottle 2 18a outer layer of preform 1 19 inner layer of PET bottle 2 19a inner layer of preform 1 20 middle layer of PET bottle 2 20a preform 1 Middle layer 30 Upper part 31 Hot runner nozzle 32 Mold 32a Cavity 32b Gate 33a Straight channel 33b First cylindrical channel 34 Second cylindrical channel 35 Check valve (open valve)
36 first inlet 37 second inlet 39a first junction 39b second junction 70 barrel 80 bottom

Claims (8)

  In a multi-layered preform having an opening, a body and a bottom and an annular support ring projecting outward from the opening, the intermediate layer is surrounded by the base layer in the opening and continuous. A preform characterized in that it is provided.   The preform according to claim 1, wherein the intermediate layer is made of a heat-resistant material.   The intermediate layer is provided between a position separated by 1 mm from the top surface of the mouth toward the bottom and a position separated by 3 mm from the support ring toward the bottom from the support ring. The preform according to claim 1, characterized in that   The intermediate layer is provided continuously from a position 3 mm apart from the top surface toward the bottom and a position 4 mm apart from the support ring toward the bottom. The preform as described in 1-2.   The preform according to any one of claims 1 to 4, wherein the weight of the intermediate layer is 1.5 weight percent to 3 weight percent.   In the method of manufacturing a preform by co-injection molding in which one material is injected and the other material is injected, the first material is injected all the time from the injection start time to the injection end time, and the injection start of the first material is started After that, the second material is sandwiched by the first material and the injection is started, and the second material starts the injection with the first material at the start of injection or immediately after the start of injection The method for producing a preform according to any one of claims 1 to 5, wherein a blending ratio of the second material is 1.5 weight percent to 3 weight percent with respect to the entire preform.   In the method of manufacturing a preform by co-injection molding in which one material is injected and the other material is injected, the first material is continuously injected from the start of the injection to the end of the injection, and the second The material is started to be injected immediately after the start of the injection, and the injection of the second material is started when the injection amount of the second material reaches 1.5% by weight to 3% by weight with respect to the entire preform. The method according to any one of claims 1 to 5, wherein the method is finished.   A plastic bottle, wherein the preform according to any one of claims 1 to 5 is formed by blow molding.

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