JP2732299B2 - Method and apparatus for producing heat-resistant multilayer bottle - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method and an apparatus for producing a polyester bottle having excellent heat resistance and extremely small heat shrinkage.

[Problems to be solved by conventional technology and invention]

In recent years, so-called hot fill, in which a polyester bottle is filled with a liquid at 80 to 95 ° C., and pasteurizing by hot shower, have been performed, and therefore, excellent heat resistance near the mouth of the bottle has been required. Was.
This is because the mouth is first exposed to a hot liquid in a hot fill, and it is common to pour the hot shower from above the bottle even in pasteurizing with a hot shower.

However, a polyester bottle obtained by ordinary biaxial stretch blow molding has no heat resistance because the mouth is left unstretched, and cannot be used for filling a liquid at 80 to 95 ° C.

Under such circumstances, various attempts have been made to impart heat resistance to the polyester bottle, and in particular, a method of imparting heat resistance by crystallizing the mouth is particularly common.

Furthermore, a widely used method for imparting heat resistance to a polyester bottle is a method in which a polyester and a heat-resistant resin are co-injected into a multi-layered preformed product, which is stretch blow-molded. A typical example is disclosed in JP-A-63-19208. However, in this example, one heat-resistant resin layer is co-injected between the polyester layers, and has only three heat-resistant resin layers at the opening end of the mouth of the preform. . Therefore, it cannot be said that the heat resistance of the entire mouth portion is sufficient.

For this reason, we have conducted intensive research on preforms that can be molded into polyester bottles with a multilayered heat-resistant resin layer at the mouth, especially for multilayer containers having a triple or quadruple heat-resistant resin layer over the entire mouth. Filed earlier (Japanese Patent Application No. 63-125586).

However, when pasteurizing by hot fill or hot shower is applied, it is desirable to use a mouth having more excellent heat resistance. Therefore, it is desired to develop a bottle that contains more heat-resistant resin near the mouth. It is rare.

In addition, since heat-resistant resins are generally expensive, they are stretched,
No heat-resistant resin is used on the body or the bottom that can be given heat resistance by heat setting, and the bottom that can be thickened and does not directly take a hot shower. It is desired to develop a low-cost bottle in which a heat-resistant resin is concentrated on a transition portion from a mouth portion to a shoulder portion which is not sufficiently stretched and a shoulder portion which directly receives a hot shower from above.

By the way, a lot of heat-resistant resin is arranged in the vicinity of the mouth, and a stretch-molded pre-formed product having a different ratio containing the heat-resistant resin by each part such that the heat-resistant resin is also arranged on the shoulder,
When an attempt is made to manufacture a heat-resistant bottle, a whitening phenomenon may be observed in a part of the bottle, or deformation such as temporal deformation or heat shrinkage may be observed. This is considered to be due to the difference in the ratio of the heat-resistant resin contained in each part of the bottle and the difference in the stretch ratio during blow molding in each part of the bottle.

Therefore, an object of the present invention is to produce a bottle having excellent heat resistance without causing whitening phenomenon, deformation with time, heat shrinkage, etc., from a preformed product in which a large number of heat resistant resin layers are arranged particularly near the mouth. A method and apparatus are provided.

[Means for solving the problem]

As a result of earnest research to solve the above-mentioned problems, the present inventor formed heat resistance having five heat-resistant resin layers at the mouth and three heat-resistant resin layers at the shoulder, Immediately after it is stretch blow-molded, heat treatment suitable for the ratio, stretch ratio and wall thickness of each part of the molded product is performed in the molding die, so that it is sufficient for pastelizing by hot fill or hot shower. The present inventors have discovered that a bottle having excellent heat resistance, which is resistant to heat, and excellent in dimensional properties that does not undergo deformation due to release, aging, or heat, has been completed, and the present invention has been completed.

That is, the method of the present invention for producing a heat-resistant multilayer bottle comprising a polyester layer and a heat-resistant resin layer comprises the steps of (a) a mouth portion, a support ring provided at a lower end of the mouth portion, and a shoulder following the support ring. Having a nine-layer structure including five heat-resistant resin layers at least below the mouth, and including three heat-resistant resin layers at the shoulders. Forming a multilayer preform having a layer structure; (b) placing the multilayer preform in a blow molding die; (c) blowing heated and pressurized air into the multilayer preform to form a biaxial Stretch blow molding is performed. (D) While maintaining the blown heated air for 3 to 50 seconds, the temperature of the mold inner wall in contact with the body and shoulder of the obtained bottle is set to 85 to 130 ° C. 80 ℃ or less,
Heat-treating the bottle; (e) blowing a cooling fluid into the bottle to rapidly cool the bottle; and (f) releasing the bottle.

Further, a multilayer preform having a mouth portion, a support ring provided at a lower end of the mouth portion, a shoulder portion following the support ring, a body portion and a bottom portion, comprising a polyester layer and a heat-resistant resin layer. The apparatus of the present invention for producing a heat-resistant multilayer bottle comprises a blow mold, a blow mandrel attached to the mold, and a multilayer attached to the center of the blow mandrel for biaxial stretch blow molding. A stretching rod inserted into a preform, wherein the mold comprises a mouth mold, a shoulder mold, a body mold, and a bottom mold, and four molds constituting the mold. The blow mandrel has a heating / pressurizing air flow path and a cooling fluid flow path separated from the heating / pressurizing air flow path. Blowing compressed air into the multilayer preform, After low molding, characterized by rapidly cooling the bottles obtained by flowing a cooling fluid.

 Hereinafter, the present invention will be described in detail.

 First, the resin used in the present invention will be described.

As the polyester resin, a thermoplastic resin comprising a saturated dicarboxylic acid and a saturated dihydric alcohol can be used.
As saturated dicarboxylic acids, terephthalic acid, isophthalic acid, phthalic acid, naphthalene-1,4- or 2,6-dicarboxylic acid, diphenyl ether-4,4'-dicarboxylic acid, diphenyl dicarboxylic acids, diphenoxyethane diethane dicarboxylic acids Aromatic dicarboxylic acids such as adipic acid,
Aliphatic dicarboxylic acids such as sebacic acid, azelaic acid and decane-1,10-dicarboxylic acid, and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid can be used.
As the saturated dihydric alcohol, ethylene glycol, propylene glycol, trimethylene glycol,
Aliphatic glycols such as tetramethylene glycol, diethylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, hexamethylene glycol, dodecamethylene glycol, neopentyl glycol, alicyclic glycols such as cyclohexane dimethanol, 2,2-bis (4'-β-hydroxyethoxyphenyl) propane, other aromatic diols and the like can be used. A preferred polyester is polyethylene terephthalate consisting of terephthalic acid and ethylene glycol.

The polyester resin used in the present invention has an intrinsic viscosity of 0.5 to
It has a value in the range of 1.5, preferably 0.55 to 0.8. Such polyesters are also produced by melt polymerization,
Those subjected to a reduced pressure treatment or a heat treatment in an inert gas atmosphere at a temperature of 50 ° C., or those obtained by solid phase polymerization to reduce the content of oligomers and acetaldehyde, which are low molecular weight polymers, are preferable.

Further, as the heat-resistant resin, polyarylate, polycarbonate, polyethylene naphthalate, polyacetal, polysulfone, polyetheretherketone, polyethersulfone, polyetherimide, polyphenylenesulfide and a blend polymer of these resins and polyethylene terephthalate, and the above Blend polymer between heat resistant resins, and 2 of the above heat resistant resins
A blend polymer of at least one kind of resin and polyethylene terephthalate, a U polymer (manufactured by Unitika, a blend polymer of polyarylate and polyethylene terephthalate) and the like can be used.

In the polyester resin or the heat-resistant resin used in the present invention, a stabilizer as long as the object of the present invention is not impaired,
Pigments, antioxidants, thermal degradation inhibitors, UV degradation inhibitors,
Additives such as antistatic agents and antibacterial agents and other resins can be added in appropriate amounts.

Next, in order to clearly show the multilayer structure of the bottle manufactured by the method of the present invention, the multilayer structure will be described using a preform that can be formed into the bottle of the present invention.

FIG. 1 is a schematic sectional view showing an example of a multilayer preform to which the method of the present invention can be applied (however, the layer structure is omitted), and FIG. 2 is a multilayer preform shown in FIG. It is a partial enlarged view which shows an example of the multilayer structure of a molded article in detail.

The multilayer preform comprises a mouth 1, a shoulder 2, a support ring 5 provided therebetween, a body 3, and a bottom 4, and a portion of the mouth 1, the support ring 5, and the shoulder 2. Has a multilayer structure comprising a heat-resistant resin layer and a polyester layer.

As shown in detail in FIG. 2, the mouth 1 is composed of a screwed portion 11 and a part of the support ring portion 12, and the screwed portion 11 is a mouth end seal between the open end 16 and the first thread 17. Part 13;
It comprises a screw / locking ring portion 14 between the first thread 17 and the locking ring 18. Also, a portion (mouth 1 + support ring 5) where the screw tightening portion 11 and the support ring portion 12 are combined is called a head pressure applying portion 15, and a large head pressure is applied at the time of capping. The head pressure applying portion 15 is a portion that is not stretched even by stretch blow molding.

The mouth 1 having such a shape has a multilayer structure in which the heat-resistant resin layers 6 and the polyester layers 7 are alternately formed. Layers (6a to 6e). On the other hand, the polyester layer 7 exists between the heat-resistant resin layers, and has four layers 7a to 7d.

The opening end 16 is entirely covered with the heat-resistant resin layer 6. Further, the outermost heat-resistant resin layer 6a is substantially continuous up to the upper surface 5a and the outer end surface 5b of the support ring 5.

On the other hand, the shoulder portion 2 includes, in order from the outside, a polyester layer 7a, a heat-resistant resin layer 6b, a polyester layer 7b, a heat-resistant resin layer 6c, a polyester layer 7c, a heat-resistant resin layer 6d, and a polyester layer 7d.
Here, the heat-resistant resin layer has three layers.

In the lower surface 5c of the support ring 5, the root portion of the ring is substantially made of a polyester layer. Since there is no relatively brittle heat-resistant resin layer at the root of the support ring 5 to which the stress is applied in this way, the support ring 5 can be prevented from being applied.

The thickness of the heat-resistant resin layers 6a to 6e is not particularly limited, but the ratio of the heat-resistant resin layer 6 to the opening end 16 increases as it approaches the opening end 16. The ratio of the heat-resistant resin layer 6 is
The weight ratio is preferably as follows.

Mouth end seal 13 (from opening end 16 to first thread 17)
... 70% or more Screw tightening part 11 (from opening end 16 to lower end of locking part 18) ... 40% or more Head pressure applying part 15 (from opening end 16 to lower end of support ring 5) ... 30% 3% or more of shoulders 2... 3% or more By defining the ratio of the heat-resistant resin layer 6 in this manner,
A bottle capable of sufficiently withstanding a hot fill for filling a liquid at 80 to 95 ° C. or a pasteurizing of applying a hot shower at 70 to 80 ° C. from above the bottle for about 30 minutes can be obtained.
The more preferable ratio of the heat-resistant resin layer 6 is 80 to 90%, 50 to 60%, 40 to 50%, and 5 to 10% in the above four portions.

The above-mentioned multilayer preform can be formed by the following method.

The molding of the multilayer preform can be performed by a co-injection molding method, which uses a hot runner nozzle schematically shown in FIG. 3 and performs a timing of co-injection of a polyester resin and a heat-resistant resin. Is set as illustrated in FIG.

First, the hot runner nozzle 30 shown in FIG. 3 has two flow paths A and B, and the flow path A further has a central straight flow path A _1.
If, divided equally into a cylindrical channel A ₂ provided on the outer side. The channel B is provided between the two channels A ₁ and A ₂ in a cylindrical shape. A check valve 31 is provided at the upper end of the central flow path A ₁ , and the check valve 31 is movable up and down by a difference in resin pressure between the flow path A ₁ and the flow path B.
When the resin pressure is high, the flow path B can be opened. Flow path B is open to the flow path A _1, the flow path A ₁ and the flow path A ₂ are leaving the hot runner nozzle 30 joins above, the injection mold 40
Of the cavity 41.

The production process of a multilayer preform using such a hot runner nozzle 30 is illustrated in the schematic diagram of the co-injection program shown in FIG. 4 and the state of the co-injection shown in FIGS. 5 (a) to (d). It is explained along. In this example, a polyester resin is allowed to flow through the flow path A, and a heat-resistant resin is allowed to flow through the flow path B.

First, in step 1, a polyester resin is injected from the channel A. At this time, the check valve 31 of the hot runner nozzle 30
, As shown in the FIG. 5 (a), is closed by the injection pressure of the polyester resin, only the polyester resin is injected from the flow channel A ₁ and A _2.

Next, in step 2, the injection rate of the polyester resin is reduced. Further, as Step 3, the heat-resistant resin is injected from the flow path B while the injection of the polyester resin is continued in the same manner as in Step 2. At this time, since the injection pressure of the heat-resistant resin is higher than the injection pressure of the polyester resin, the chuck valve 31 opens according to the difference, and the heat-resistant resin is injected correspondingly.

The injected heat-resistant resin in step 3 proceeds as shown in the FIG. 5 (b), 2 one polyester resin layer 70a which is emitted from the flow passage A ₁ and A ₂ Prefecture, between 70b. At this time, since the heat-resistant resin layer 60 advances between the two polyester resin layers 70a and 70b without contacting the inner wall of the molding die, a decrease in resin temperature is small and fluidity is large. Therefore, it moves at a higher speed than the polyester resin layers 70a and 70b.

Further, in step 4, the injection rate of the polyester resin is increased without stopping the injection of the heat-resistant resin. Then, as shown in FIG. 5 (c), in addition to the polyester resin layers 70a and 70b injected in step 3, the polyester resin layers 70c and 70d newly advance in the resin. At this time, the check valve 31 is somewhat closed by the injection pressure of the polyester resin, so that the heat-resistant resin is thinly injected.
Further, since the polyester resin layers 70c and 70d advance between the resin layers, they move at a higher speed than the polyester resins 70a and 70b.

Next, as step 5, injection of the heat-resistant resin is stopped, polyester resin is injected in an amount sufficient to fill the mold (FIG. 5 (d)), and finally, the pressure in the mold 40 is adjusted (maintained). Pressure) (step 6), and the injection is terminated.

If a multilayer preform is molded by the co-injection program described above, at least the lower part of the mouth 1 has a nine-layer structure (five heat-resistant resin layers) and the shoulder part 2 has a seven-layer structure (heat-resistant resin layer). A resin layer (three resin layers) is formed. Hereinafter, the reason will be described with reference to schematic diagrams (FIGS. 6 (a) to 6 (e)) showing the leading end of the co-injected resin layer.

In step 3, as shown in FIG.
When the heat-resistant resin is injected between the two polyester resins 70a and 70b, the heat-resistant resin layer 60 advances between the two polyester resin layers 70a and 70b, but flows through the center.
Since the speed is faster, the heat-resistant resin layer 60 approaches the front end 50 of the polyester resin as shown in FIG. 6 (a). Then, as shown in FIG. 6 (b), the heat-resistant resin layer 60 overtakes the polyester resin layers 70a and 70b and occupies the front end 50 of the resin layer. At this point, the resin layer is polyester resin layer 70a / heat-resistant resin layer 60 / polyester resin layer 7
In the three-layer structure of FIG. 6B, as shown in FIG. 6C, the heat-resistant resin layer 60 gushes from the tip 50 and covers the tip of the polyester resin layers 70a and 70b. That is, the two polyester resin layers 70a and 70b travel inside the heat-resistant resin 60, so that part of the heat-resistant resin 60 remains near the inner wall surface of the mold. At this point, the resin layer has a five-layer structure of heat-resistant resin layer 60a / polyester resin layer 70a / heat-resistant resin layer 60b / polyester resin layer 70b / heat-resistant resin layer 60c.

Next, in step 4, a heat-resistant resin and a polyester resin are co-injected as shown in FIG. 5 (c). Since the new polyester resin layers 70c and 70d advance between the resin layers, they advance earlier than the preceding two polyester resin layers 70a and 70b as shown in FIG. 6 (d). In addition, since the fluidity of the heat-resistant resin layer portions in contact with the polyester resin layers 70a and 70b is slightly lowered due to the temperature drop, the polyester resin layers 70c and 70d advance faster than that.
Therefore, the outside of the heat-resistant resin layer 60 is a polyester resin layer.
It will be left between 70a and 70c and between polyester resin layers 70b and 70d, respectively, and finally, FIG. 6 (e)
As shown in the figure, new heat-resistant resin layers 60d and 60e, respectively.
Is formed. Therefore, the resin layer has a nine-layer structure including five heat-resistant resins 60a to 60e.

As described above, by appropriately setting the amount and timing of the resin to be injected in consideration of the volume of each portion of the cavity in the mold, at least the lower portion of the mouth 1 includes the five heat-resistant resin layers. A multi-layer preform having a nine-layer structure can be manufactured. The three heat-resistant resin layers provided on the shoulder of the multilayer preform are the heat-resistant resin layers shown in FIG.
60d, 60b and 60e.

As is clear from the above description, the condition for forming the five heat-resistant resin layers at least at the lower part of the mouth portion is that the step 4 in FIG. 4 is performed. By increasing the injection rate of the polyester resin without stopping the injection of the resin, FIGS. 6 (d) to 6 (e)
This causes the phenomenon shown in FIG. On the other hand, if the injection of the heat-resistant resin is stopped and the injection rate of the polyester resin is increased, the central heat-resistant resin layer 60b is not maintained long enough, and becomes short as it progresses in the cavity. (Because the heat-resistant resin layer 60b is located at the most central position), it disappears when it reaches the mouth, and the heat-resistant resin layer becomes a total of four layers.

In the production of such a multilayer preform, it is necessary to firmly define the cylinder temperature and cylinder pressure at the time of injection, the viscosity difference between the polyester resin and the heat-resistant resin, and the like. In particular, since the viscosity of the resin greatly depends on the temperature, it is important to keep the temperature of the resin constant. For example, when a U-polymer is used as the heat-resistant resin and polyethylene terephthalate is used as the polyester resin, The resin temperature is preferably 270 to 310 ° C, and the temperature of polyethylene terephthalate is preferably 260 to 300 ° C. More preferred resin temperature is 280-295 ° C for U polymer
And 270-285 ° C. for polyethylene terephthalate.

As described above, first, a nine-layer structure having five heat-resistant resin layers at least at the lower part of the mouth is provided.
A multi-layer preform having a seven-layer structure having a heat-resistant resin layer is molded and then stretch-blown to produce a multi-layer heat-resistant bottle.

FIG. 7 is a cross-sectional view schematically showing an example of a stretch blow molding apparatus that can be used to carry out the method for producing a heat-resistant multilayer bottle of the present invention. This device has a mouth type 101
A stretch blow molding mold 100 including a shoulder mold 102, a body mold 103, and a bottom mold 104, a blow mandrel 105 that can be mounted on the mouth mold 101 in a sealed state, and attached to a lower end of the blow man drel 105. Extending rod 106, a fixed block 116 attached to the upper end, and an extended rod fixing block 117. Here, the extension rod 106 is positioned at the center of the blow mandrel 105 by the extension rod slide sleeve 112. Also, the blow mandrel 105 is
Has a cylindrical portion 105a extending into the cavity of the mold 100, and the cylindrical portion 105a has a length reaching near the upper portion of the shoulder of the bottle. As a result, the blown air flows into the preform without directly hitting the shoulder of the multilayer preform, so that the vicinity of the shoulder of the molded product is cooled even if the blow air performs so-called adiabatic expansion. However, whitening near the shoulder of the bottle to be molded can be prevented.

An extension rod 106 extends through the center of the brillandrel 105, and there are flow paths 108 and 109 around the extension rod 106. Channel 10
8 is provided with a sheath heater 110, and the flow paths 108 and 109 are provided.
Between them, a separating sleeve 107 is provided. The extension rod 106 is formed in a tubular shape, through which a cooling fluid can flow, and a plurality of holes 111 for blowing out gas are provided in a portion protruding into the mold. The extension rod 106 has an opening 113 in the fixed block 117, and the opening 113 is connected to a cooling fluid source (not shown) through a pipe having a valve or the like (not shown). The flow passages 108 and 109 have openings 115 and 114 in the fixed block 116, respectively. The opening 114 is connected to a relief valve (not shown) via a pipe or the like (not shown) having a valve at the end. The opening 115 is connected to a pressurized air source (not shown) through a pipe having a valve or the like (not shown). When the heating / pressurizing air and the cooling fluid flow in and out, the plurality of valves attached to each pipe are appropriately opened and closed to set the gas flow path.

The multilayer preform is set in the mold 100 of such an apparatus, and stretch blow molding is performed as follows.

First, pressurized air flows into the channel 108 through the opening 115, and is discharged from the hole of the sleeve 112 while being heated to a predetermined temperature by the sheath heater 110, thereby stretching the multilayer preform. At this time, as the multilayer preform is expanded, the stretching rod 106 enters therein. In this case, the temperature of the heated and pressurized air for biaxial stretch blow molding is 50 ° C. or higher, preferably about 80 to 100 ° C., and the pressure is 15 to 50 kg / cm ² , preferably 20 to 40 kg / cm ² . .

The reason why stretch blow molding is performed using heated air is to prevent a whitening phenomenon in a portion such as a shoulder portion composed of a polyester layer and a heat-resistant resin layer.

After performing biaxial stretch blow molding with heated and pressurized air,
Each part of the bottle is heat-treated at the temperature of the mold while holding the blown air for 3 to 50 seconds and pressing the bottle against the inner wall surface of the mold. Specifically, the mouth mold 101 of the mold 100
Is in contact with the mouth of the multi-layer preform, which contains a large amount of heat-resistant resin and is hardly stretched, and the shoulder mold 102 comes in contact with the shoulder containing some heat-resistant resin and having a moderate stretching ratio, The part mold 103 is in contact with the body of the multilayer preformed product which is most stretched without containing the heat-resistant resin, and the bottom mold 104 is made with the bottom of the thick multilayer preformed product which does not contain the heat-resistant resin and has a low stretching ratio Contact. Here, each part (the mouth mold, the shoulder mold, the body mold and the bottom mold) of the mold 100 is maintained at a predetermined temperature, and the bottle is heat-treated at four different temperatures. The temperature of each part of the mold is set in consideration of the difference in the ratio of the heat-resistant resin and the draw ratio in each part of the multilayer preform used. Specifically, the temperature of the mouth mold is slightly different depending on the type of heat-resistant resin used, but the temperature is 20 to 60.
℃, shoulder mold temperature is 95 ~ 130 ℃, body mold temperature is 85 ~ 130
° C and the temperature of the bottom mold should be 60-80 ° C. Here, in order to prevent whitening of the heat-resistant resin layer, the temperature of the shoulder mold is preferably set to be equal to or higher than the temperature of the body mold.

In the next step, the heated air is passed through the opening 114 through the flow path 109.
The bottle is further evacuated and the cooling fluid is blown through a stretching rod to quench the bottle. Due to this rapid cooling, deformation of the molded bottle at the time of mold release can be significantly reduced, and thereby dimensional stability of the bottle can be obtained.

The cooling fluid is applied to the extension rod 1 at a constant pressure from the opening 113.
It flows into 06. As described above, since a large number of holes 111 are provided at the tip of the stretch rod 106 (the portion inserted into the multilayer preform), the cooling air is discharged into the stretch blow-molded bottle. Cool the bottle. The temperature of the cooling fluid 50 ° C. or less, and preferably about 5 to 20 ° C., the pressure is 0~30kg / cm ^2, preferably 5~15kg / cm ^2. As the cooling fluid, either cooling air or fluid nitrogen or a gas obtained by vaporizing the same can be used.

After the cooling fluid has been cooled, it is discharged from the opening 114 through the flow path 109 in the mandrel 105, so that the stretch-blown bottle always comes into contact with fresh cooling fluid and is rapidly cooled. At this time, the pressure level of the cooling fluid is kept constant by the relief valve connected to the opening 114.
Usually, the cooling time is about 1 to 10 seconds for cooling air and about 1 to 5 seconds for liquid or vaporized nitrogen gas. The temperature of the molding container is cooled down to about 60 to 90 ° C. by rapid cooling. After quenching, the mold is immediately released before being reheated by the blow mold, and the heat-resistant multilayer bottle 120 as shown in FIG.
Can be obtained.

According to the method as described above, a bottle having excellent heat resistance and having a multilayer heat-resistant resin layer in the mouth 1 and the shoulder 2 can be manufactured. This is because the hottest parts in the hot fill or pastelizing process are the mouth and shoulders of the bottle. On the other hand, for the body and bottom of the bottle, the heat-resistant resin layer is not substantially formed,
The above heat treatment is sufficient because it can withstand the temperature condition of hot fill or pasteurizing. Since the heat-resistant resin is relatively expensive, the cost of the entire bottle can be reduced by not forming the heat-resistant resin layer on the body and the bottom.

In the above description, the portion having five heat-resistant resin layers is at least the lower portion of the mouth, but in the other portion of the mouth, the adjacent heat-resistant resin layers are fused due to injection conditions. Sometimes. However, even in this case, since the ratio of the heat-resistant resin layer is large, it is clear that the mouth has sufficient heat resistance. Therefore, it is not necessary that the entire mouth has five heat-resistant resin layers, but it is sufficient if at least the lower part of the mouth has five heat-resistant resin layers.

〔Example〕

 The present invention is described in more detail by the following examples.

Example 1 Mitsui PETJ125 as polyethylene terephthalate resin
(Mitsui Petrochemical Co., Ltd.) and a multi-layered pre-injection molding method using a blended polymer of polyethylene terephthalate and polyarylate (U polymer 8400, manufactured by Unitika) (hereinafter referred to as U polymer) as a heat resistant resin. A molded article was molded.

ASB650NHT manufactured by Nissei ASB Machine Co., Ltd.
Using the mold, the hot runner nozzle shown in FIG. 3 was connected, and the multilayer preform was molded by the co-injection program shown in FIG.

At this time, the injection barrel temperature on the polyethylene terephthalate side was 272 ° C, and the injection barrel temperature on the U polymer side was 2 ° C.
84 ° C. The injection rate of polyethylene terephthalate was 7.74 g / sec in step 1 and 1.8 g in steps 2 and 3.
/ Sec, increased from 1.8 g / sec to 2.8 g / sec in step 4, and maintained 2.8 g / sec in step 5. The U-polymer was weighed up to 2.8 g / sec in steps 3 and 4.

The obtained multilayer preform was cut in the axial direction and the cross section was observed. As a result, the lower part of the mouth and the shoulder are
As shown in the figure, each of the nine layers (five heat-resistant resin layers)
And seven layers (three heat-resistant resin layers). The percentage of U polymer in each part of the multilayer preform is 85% at the mouth end seal part 13 and 85% at the screw tightening part 11.
55%, 44% at the head pressure applying portion 15, and 4% at the shoulder 2.

Next, the obtained multilayer preform was placed in a stretch blow molding die 100 shown in FIG. Mouth mold for this mold 10
1, set the temperature of the shoulder mold 102, the trunk mold 103 and the bottom mold 104 to 40 ° C, 120 ° C, 105 ° C, and 70 ° C respectively, and extend the rod.
While inserting 106 into the preform, heated and compressed air at 80 ° C. and 30 kg / cm ² was blown out to perform stretch blow molding. At this time, the air blown was held for 18 seconds and then vented. afterwards,
Cooling air at 25 ° C. and 10 kg / cm ² was blown out from the stretching rod 106 to perform cooling and obtain a heat-resistant multilayer bottle.

The resulting heat-resistant multilayer bottle was subjected to 83-87 ° C hot fill and 65-70 ° C pasteurizing,
It was confirmed that the mouth and shoulder had good heat resistance.

〔The invention's effect〕

As described in detail above, in the method of the present invention, the mouth, shoulder, trunk, and bottom of the blow-molded bottle are heat-treated at different temperatures. Even with such a structure, it is possible to manufacture a bottle having excellent heat resistance without causing thermal deformation or temporal deformation without causing a whitening phenomenon.

Therefore, even a bottle having five heat-resistant resin layers at the mouth and three heat-resistant resin layers at the shoulder and not including the heat-resistant resin layers at the body and bottom can be easily manufactured by stretch blow molding. it can. Such a bottle has heat resistance sufficient to apply hot filling, pasterizing by hot shower, or the like, due to the heat-resistant resin layer disposed at the mouth and shoulder.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing an example of a multilayer preform to which the method of the present invention can be applied, and FIG. 2 shows a multilayer structure at the mouth and shoulder of the multilayer preform of FIG. FIG. 3 is a partially enlarged cross-sectional view showing an example in detail; FIG. 3 is a cross-sectional view showing an example of a hot runner nozzle used to manufacture a multilayer preform; FIG. 5 (a) to 5 (d) are partial schematic cross-sectional views showing a state where a heat-resistant resin and a polyester resin are co-injected, and FIG. 6 (a) to FIG. e) is a schematic diagram showing a state in which a multilayer structure is formed by the heat-resistant resin and the polyester resin, and FIG. 7 is a cross-sectional view showing an apparatus for manufacturing a heat-resistant multilayer bottle according to one embodiment of the present invention. DESCRIPTION OF SYMBOLS 1 ... Mouth part 2 ... Shoulder part 3 ... Body part 4 ... Bottom part 5 ... Support ring 6, 6a-6e ... Heat resistant resin layer 7, 7a-7d ... Polyester layer 11 ... Screw fastening part 12 ... Support ring part 13 ... Sealing end part 14 ... Screw / locking ring part 15 ... Head pressure applying part 30 ... Hot runner nozzle 31 ... Check valve 40 ... Injection molding die 41 ... Cavity 100 …………………………………………………………………………………………… …………………………………………………………………… Plunge 105 105 105 105 ヒ ー タ ヒ ー タ ヒ ー タ ヒ ー タ ヒ ー タ ヒ ー タ ヒ ー タ ヒ ー タ ヒ ー タ ヒ ー タ ヒ ー タ ヒ ー タ. 111 ...... holes 113, 114, 115 ...... opening 116 ...... blow mandrel fixed block 117 ...... stretching rod fixing block 120 ...... refractory multilayer bottle a _1, a _2, B ...... hot runner flow path

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takemi Shibuya 1-1-1 Ichigaya-Kagacho, Shinjuku-ku, Tokyo Inside Dai Nippon Printing Co., Ltd. (72) Inventor Tsunoo Yamada 1 Ichigaga-cho, Shinjuku-ku, Tokyo JP-A-2-281909 (JP, A) JP-A-1-146707 (JP, A) JP-A-61-148022 (JP, A) Kohei 1-24056 (JP, B2)

Claims (4)

(57) [Claims] 1. A method for producing a heat-resistant multilayer bottle comprising a polyester layer and a heat-resistant resin layer, comprising: (a) a mouth, a support ring provided at a lower end of the mouth, and a shoulder connected to the support ring. Having a nine-layer structure including five heat-resistant resin layers at least below the mouth, and including three heat-resistant resin layers at the shoulders. Forming a multilayer preform having a layer structure; (b) placing the multilayer preform in a blow molding die; (c) blowing heated and pressurized air into the multilayer preform to form a biaxial Stretch blow molding is performed. (D) The heated air blown is held for 3 to 50 seconds, and the temperature of the mold inner wall in contact with the body of the obtained bottle is set to 85%.
(E) blowing a cooling fluid into the bottle to quench the bottle, and (f) releasing the bottle. 2. The method according to claim 1, wherein a blow mold including a mouth mold, a shoulder mold, a body mold, and a bottom mold is used, and the temperature of the mouth mold is set at 20 degrees. ~ 60 ° C, the temperature of the shoulder mold is 95-130 ° C, the temperature of the body mold is 85-130 ° C,
And a method wherein the temperature of the bottom mold is set to 60 to 80 ° C., and the biaxially stretch blow-molded bottle is heat-treated in the molding die. 3. A multilayer comprising a mouth portion, a support ring provided at a lower end of the mouth portion, a shoulder portion following the support ring, a body portion and a bottom portion, comprising a polyester layer and a heat-resistant resin layer. In a device for producing a heat-resistant multilayer bottle from a preform, a blow molding die, a blow mandrel attached to the die, and a multilayer attached to the center of the blow mandrel and subjected to biaxial stretch blow molding. Having a stretch rod inserted into the preform, wherein the mold comprises:
The mold includes a mouth mold, a shoulder mold, a body mold, and a bottom mold. The four molds constituting the mold can independently set a temperature, and the blow mandrel is heated and pressurized. An air flow path and a cooling fluid flow path separated from the heating and pressurizing air flow path are provided, and the heating and pressurizing air is blown into the multilayer preform, blow-molded, and then cooled. An apparatus characterized by rapidly cooling a bottle obtained by flowing a fluid. 4. The apparatus according to claim 3, wherein said blow mandrel has a cylindrical portion extending into a cavity of said mold, said cylindrical portion substantially corresponding to an upper portion of a bottle shoulder. An apparatus characterized by having a length reaching up to.