JP3063989B2 - Heat resistant UV absorbing multilayer bottle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a multilayer polyester bottle having a layer having excellent heat resistance and an ultraviolet absorbing property.

[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.

Under such circumstances, various attempts have been made to impart heat resistance to polyester bottles.

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 to obtain a multilayered preform, 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. The application was 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.

By the way, in the case of using beverages such as beer or food, foods, chemicals, etc. as contents, bottles that transmit ultraviolet light pose a problem in terms of storage stability of the contents. It is necessary to use a bottle having a low transmittance.

Therefore, an object of the present invention is to provide a multilayer bottle having excellent heat resistance and ultraviolet absorption, and particularly to provide an ultraviolet absorption multilayer bottle having excellent heat resistance in the mouth. .

[Means for solving the problem]

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that a resin layer having five layers of heat-resistant resin at the mouth and exhibiting ultraviolet absorption from substantially the center of the shoulder to the lower end of the body is provided. Forming a multi-layer preformed product having, and if stretch blow-molding it, has heat resistance enough to withstand pasteurizing by hot fill or hot shower,
The present inventors have discovered that a bottle having a low ultraviolet transmittance can be manufactured, and completed the present invention.

That is, the heat-resistant ultraviolet absorbing multilayer bottle of the present invention is:
A heat-resistant ultraviolet-absorbing multilayer bottle comprising a polyester layer, a heat-resistant resin layer, and a resin layer having an ultraviolet absorbing property, comprising a mouth, a support ring provided at a lower end of the mouth, and a shoulder following the support ring. Part, a body part and a bottom part, and the mouth part has a heat-resistant resin layer / polyester layer / heat-resistant resin layer / polyester layer / heat-resistant resin layer / polyester layer / heat-resistant resin layer / It has a nine-layer structure of a polyester layer / a heat-resistant resin layer, and a resin layer having an ultraviolet absorbing property is arranged from the shoulder portion to at least a lower end of the body portion, and the heat-resistant resin is provided on the body portion and the bottom portion. The layer is not substantially formed, and the heat-resistant resin layer is a substantially amorphous blend polymer composed of a mixture of polyarylate and polyethylene terephthalate. The heat-resistant resin layer of the outermost layer of the mouth is formed substantially continuously from the opening end of the mouth to the support ring, and covers the upper surface of the support ring, and The heat-resistant resin does not substantially exist on the lower surface of the base of the support ring.

In a preferred embodiment of the heat-resistant multilayer bottle of the present invention, three heat-resistant resin layers continuing from the mouth are formed on the shoulder. Further, the ratio of the heat-resistant resin layer increases as approaching the opening end, and the ratio (weight ratio) of the heat-resistant resin layer is 70% or more at the mouth end seal portion and 40% or more at the screw tightening portion. In the head pressure applying section, it is 30% or more.

Further, in a preferred embodiment of the heat-resistant multilayer bottle of the present invention, the outermost heat-resistant resin layer of the mouth is formed substantially continuously from the opening end of the mouth to the support ring, and the shoulder portion thereof Is formed with three heat-resistant resin layers continuing from the opening.

 Hereinafter, the present invention will be described in detail.

First, the resin constituting the heat-resistant ultraviolet absorbing multilayer bottle of 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.

Polyester resin used in the production of the bottle of the present invention,
The intrinsic viscosity has a value in the range from 0.5 to 1.5, preferably from 0.55 to 0.85. In addition, such polyesters are produced by melt polymerization and are subjected to a reduced pressure treatment or a heat treatment in an inert gas atmosphere at a temperature of 180 to 250 ° C., or oligomers and acetaldehydes which are low molecular weight polymers by solid phase polymerization. Those having a reduced content are preferred.

As the heat resistant resin, a substantially amorphous U polymer (manufactured by Unitika Ltd.) composed of a blend polymer of polyarylate and polyethylene terephthalate is used.

Next, as the ultraviolet absorbing resin, a resin in which a benzophenone-based or benzotriazole-based ultraviolet absorber is kneaded in advance with a resin such as polyethylene terephthalate or a blend polymer of polyarylate and polyethylene terephthalate can be used.

Incidentally, the polyester resin used in the present invention, a heat-resistant resin or ultraviolet absorbing resin, stabilizers, pigments, antioxidants, thermal degradation inhibitors, as long as the object of the present invention is not impaired,
Additives such as an ultraviolet ray deterioration preventing agent, an antistatic agent, and an antibacterial agent and other resins can be added in appropriate amounts.

 Next, the structure of the bottle of the present invention will be described.

FIG. 1 is a schematic sectional view showing an example of the heat-resistant ultraviolet absorbing multilayer bottle of the present invention (however, the layer structure is omitted), and FIG. 2 is the mouth and shoulder of the multilayer bottle shown in FIG. FIG. 3 is a partially enlarged view showing the layer structure in detail, and FIG. 3 is a partially enlarged view showing the layer structure in the body of the multilayer bottle shown in FIG.

The heat-resistant UV absorbing multilayer bottle has a mouth 1 and a shoulder 2
And a support ring 5 provided therebetween, and a trunk 3
And a bottom 4, a mouth 1, a support ring 5,
It has a multilayer structure composed of a heat-resistant resin layer and a polyester layer from the upper part to the central part of the shoulder part 2, and has an ultraviolet absorbing resin layer and a polyester layer from the substantially central part of the shoulder part 2 to the lower end of the body part 3. Having a multilayer structure.

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. Further, a portion (mouth 1 + support ring 5) where the screw fastening 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 during cabbing. 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. It is divided into layers (6a-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. The outermost heat-resistant resin layer 6a is almost connected to the upper surface 5a and the outer end surface 5b of the support ring 5.

On the other hand, at least the upper half of 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. In this case, there are three heat-resistant resin 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 base of the support ring 5 to which the stress is applied, the application of the support ring 5 can be prevented. Further, since the entire upper surface 5a of the support ring 5 is covered with the heat-resistant resin layer, the support ring 5 has sufficient heat resistance against pasteurizing by hot fill or hot shower.

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 part 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 the opening end 16 to the lower end of the support ring 5) ... 30% or more Shoulder 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.

Also, in the multilayer bottle of the illustrated embodiment, the shoulder 2
An ultraviolet-absorbing resin layer 8 is provided from the center to the lower end of the body 3, and the ultraviolet-absorbing resin layer 8 is formed substantially at the center of the bottle wall made of polyester resin. Therefore, the ultraviolet absorbing resin layer 8 in the shoulder portion 2 is formed so as to be continuous with the heat resistant resin layer 6c formed from the mouth portion 1 to the shoulder portion 2, and a part of the lower portion of the shoulder portion 2 The ultraviolet absorbing resin layer and the heat resistant resin layer form a multilayer structure together with the polyester resin layer.

On the other hand, as shown in FIG. 3, the trunk portion 3 has a three-layer structure of a polyester layer 7, an ultraviolet absorbing resin layer 8, and a polyester layer 7. The thickness of the ultraviolet absorbing resin layer 8 at this time depends on the type of the ultraviolet absorbing agent added in advance,
Although it varies slightly depending on the amount, it is generally desirable to be about 80 μm or more. This allows the bottle to have good UV absorption.

The heat-resistant and ultraviolet-absorbing multilayer bottle having the structure described above forms a multilayer preform having a multilayer structure similar to the multilayer structure shown in FIGS. 2 and 3 in the mouth, shoulder, and body, It is manufactured by stretch blow molding it.

Here, a method of forming the multilayer preform will be described.

The multilayer preform is co-injected with a polyester resin and a heat-resistant resin or a polyester resin and an ultraviolet-absorbing resin according to an injection program illustrated in FIG. 5 using a hot runner nozzle schematically shown in FIG. Can be manufactured.

First, the hot runner nozzle 30 shown in FIG. 4 has three flow paths A, B, and C, and the flow path A further includes a central straight flow path A ₁ and a cylindrical flow path provided outside thereof. It is divided equally into a road a _2. In addition, the flow path B includes the two flow paths A ₁ ,
It is provided in a cylindrical shape between A _2. Furthermore channel C is provided again in a cylindrical manner between the central channel A ₁ and cylindrical channel B. A check valve 31 is provided at the upper part 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. Is high, the flow path B can be opened. Also, the central channel
The middle part of A ₁ and another check valve 32 is provided, check valve 32 is movable up and down by a difference in resin pressure between the flow path A ₁ and the channel C, the channel C resin When the pressure is high, the flow path C can be opened. Channel C and the 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, in communication with the cavity 41 of the injection mold 40 .

The production process of a multilayer preform using such a hot runner nozzle 30 is shown in the schematic diagram of the co-injection program shown in FIG. 5 and the state of the co-injection shown in FIGS. 6 (a) to (d). It is explained along. In this example, a polyester resin is allowed to flow through the channel A, a heat-resistant resin is allowed to flow through the channel B, and an ultraviolet absorbing resin is allowed to flow through the channel C.

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
And check valve 32, as shown in the FIG. 6 (a), is closed by the injection pressure of the polyester resin, the channel A ₁
And only the polyester resin is injected from the 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 check valve 31 opens according to the difference, and the heat-resistant resin is injected correspondingly. At this time, since the injection pressure of the ultraviolet absorbing resin has not been increased yet, the check valve 32 remains closed.

The injected heat-resistant resin in step 3 proceeds as shown in the FIG. 6 (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 the 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. 6 (c), in addition to the polyester resin layers 70a, 70b injected in step 3, the polyester resin layers 70c, 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 70d.

Next, as step 5, the injection of the heat-resistant resin is stopped, and the injection pressure of the ultraviolet absorbing resin is increased. As a result, the check valve 32 is opened, and the ultraviolet absorbing resin 80 is injected between the polyester resin layers 70c and 70d as shown in FIG. 6 (d).
At this time, since the ultraviolet absorbing resin layer 80 advances between the two polyester resin layers 70c and 70d without contacting the inner wall of the mold, the resin temperature is less reduced and the fluidity is large. Therefore, it moves at a higher speed than the polyester resin layers 70c and 70d, and tries to catch up with the tail of the heat-resistant resin layer 60 injected between the polyester resin layers 70c and 70d first. At this time, the thickness of the ultraviolet absorbing resin layer 80 can be appropriately changed by adjusting the difference between the injection pressures of the polyester resin and the ultraviolet absorbing resin.

Finally, as step 6, the pressure in the molding die 40 is adjusted (holding pressure), and the injection is completed.

If a multilayer preform is formed by the co-injection program described above, a nine-layer structure (five heat-resistant resin layers) is provided at least in the lower part of the mouth part 1, and a seven-layer structure is provided in at least the upper half of the shoulder part 2. A resin layer having a structure (three heat-resistant resin layers) is formed, and a three-layer structure of polyester layer / ultraviolet absorbing resin layer / polyester layer extends from substantially the center of the shoulder 2 to the lower end of the body 3. A resin layer will be formed.

Here, the reason why the multilayer structure formed at least in the lower part of the mouth part 1 and the shoulder part 2 becomes a nine-layer structure and a seven-layer structure, respectively, is a schematic diagram showing the tip part of the co-injected resin layer (FIG. 7). This will be described with reference to (a) to (e)).

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. 7 (a). Then, as shown in FIG. 7 (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. 7B, as shown in FIG. 7C, 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. 6 (c). Since the new polyester resin layers 70c and 70d advance between the resin layers, they advance earlier than the two preceding polyester resin layers 70a and 70b as shown in FIG. 7 (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 is left between 70a and 70c and between polyester resin layers 70b and 70d, respectively, and finally, FIG. 7 (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.

In this manner, by appropriately setting the amount and timing of the resin to be injected in consideration of the volume of each portion of the capacity in the molding die, the five heat-resistant resin layers are formed at least below the opening 1. A multilayer preform having a nine-layer structure can be manufactured. Note that 3 is provided on the shoulder of the multilayer preform.
The three heat-resistant resin layers are the heat-resistant resin layers 60d, 60b and 60e in FIG. 7 (e).

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. 5 is performed. By increasing the injection rate of the polyester resin without stopping the injection of the resin, FIGS. 7 (d) to 7 (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.

On the other hand, in the formation of the ultraviolet-absorbing resin layer, the thickness can be adjusted by the difference in injection pressure from the co-injected polyester resin as described above. It can be appropriately changed by adjusting the injection start and stop times of the absorbent resin.
Therefore, in a substantially central portion of the shoulder portion 2, the ultraviolet absorbing resin layer is formed so as to be continuous with the heat resistant resin layer, or the ultraviolet absorbing resin has a multilayer structure in which both layers are overlapped by shortening the injection start time. Or a structure in which both layers are discontinuous. Further, the ultraviolet absorbing resin layer may be formed to extend from the lower end of the body 3 to a part of the bottom 4.

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, the heat-resistant resin, and the ultraviolet absorbing resin. 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, U polymer is used as the heat-resistant resin, polyethylene terephthalate is used as the polyester resin, and polyethylene is used as the ultraviolet absorbing resin. When using a terephthalate resin kneaded with a benzotriazole-based ultraviolet absorber, the resin temperature of the U polymer is
270 to 310 ° C and the temperature of polyethylene terephthalate
260-300 ° C, UV-absorbing resin temperature 260-280 ° C
It is preferred that Preferred resin temperatures are 280-295 ° C for U-polymer, 270-285 ° C for polyethylene terephthalate, and 265-275 ° C for UV absorbing resins with benzotriazole UV absorbers.

By stretching blow molding the preform described above, it has a nine-layer structure having five heat-resistant resin layers at least at the lower part of the mouth, and has three heat-resistant resin layers at the shoulders. In addition, the heat-resistant ultraviolet-absorbing multilayer bottle of the present invention having an ultraviolet-absorbing resin layer substantially at the center of the bottle wall from substantially the center of the shoulder to the lower end of the body can be manufactured.

FIG. 8 is a cross-sectional view schematically showing one example of a stretch blow molding apparatus that can be used for producing the heat-resistant ultraviolet absorbing 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 bottle is not cooled even if the blow air performs so-called adiabatic expansion. Therefore, it is possible to prevent whitening near the shoulder of the bottle to be molded.

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 60 to 110 ° 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 of a portion formed of a polyester layer such as a body.

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 part 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 does not contain a heat-resistant resin, contains an ultraviolet-absorbing resin, and comes into contact with the body of the multilayer preform that is most stretched, and the bottom part 104 does not contain a heat-resistant resin and has a low stretching rate. Contact the bottom of the part. 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 between the ratio of the heat-resistant resin and the ultraviolet-absorbing resin and the difference in the stretching ratio in each part of the multilayer preform used. Specifically, although the temperature slightly differs depending on the type of the heat-resistant resin and the ultraviolet-absorbing resin to be used, the temperature of the mouth mold is 20%.
~ 60 ℃, shoulder mold temperature is 95 ~ 130 ℃, trunk mold temperature is 85
~ 130 ° C and the bottom mold temperature should be 60 ~ 80 ° C.

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. This quenching can significantly reduce the residual stress in the molded bottle, thereby preventing deformation when the bottle is released from the blow heat treatment mold.

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 liquid nitrogen or a gas obtained by evaporating 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 ° C. to 90 ° C. by rapid cooling. After quenching, the mold is released, and a heat-resistant ultraviolet absorbing multilayer bottle 120 as shown in FIG. 8 can be obtained.

Bottles manufactured by the method described above are:
Since the mouth 1 and the shoulder 2 have a multilayer heat-resistant resin layer,
Excellent heat resistance. 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, although the heat-resistant resin layer is not substantially formed on the body and bottom of the bottle, it is sufficient because the above heat treatment can withstand a temperature condition of 60 ° C. for about 20 minutes. 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.

In addition, the above-described bottle has a structure in which the ultraviolet absorbing resin layer is arranged from substantially the center of the shoulder to the entire body, so that the contents can be reliably protected from ultraviolet rays.

〔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.), 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, and a polyethylene terephthalate resin as an ultraviolet absorbing resin Was prepared by kneading 2- (5-methyl-2-hydroxyphenyl) benzotriazole in advance, and a multilayer preform was molded by a co-injection molding method. Nissei ASB Machine Co., Ltd.
Using a model ASB650NHT, a hot runner nozzle shown in FIG. 4 was connected, and a multilayer preform was molded by a 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
The injection barrel temperature on the resin side at which the ultraviolet absorbent was kneaded was set at 270 ° C. The injection rate of polyethylene terephthalate was increased to 7.74 kg / sec in step 1, 1.8 g / sec in steps 2 and 3, from 1.8 g / sec to 2.8 g / sec in step 4, and maintained at 2.8 g / sec in step 5. did. U
The polymer was brought to a maximum of 2.8 g / sec in steps 3 and 4. The injection rate of the ultraviolet absorbing resin was set to 1.03 g / sec in step 5.

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
Very similar to the multilayer structure at the mouth and shoulders of the bottle shown in the figure, 9 layers each (5 layers of heat-resistant resin)
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.

The ultraviolet-absorbing resin layer made of a resin in which 2- (5-methyl-2-hydroxyphenyl) benzotriazole is mixed with polyethylene terephthalate is a polyester resin that extends from almost the center of the shoulder to the entire body of the multilayer preform. It was formed in the center of the layer. At this time, the thickness of the ultraviolet absorbing resin layer in the body was 20% of the thickness of the body of the multilayer preformed product.

Next, the obtained multilayer preform was placed in a mold 100 for stretch blow molding 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, 115 ° C, and 70 ° C respectively,
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, thereby obtaining a heat-resistant ultraviolet absorbing multilayer bottle.

83 to the resulting heat-resistant UV-absorbing multilayer bottle
Although hot fill at 87 ° C. and pasteurizing at 65 to 70 ° C. were performed, it was confirmed that the mouth and shoulder had good heat resistance.

〔The invention's effect〕

As described in detail above, the heat-resistant ultraviolet-absorbing multilayer bottle of the present invention has at least the lower portion of the mouth formed of nine layers including five heat-resistant resin layers, and is substantially formed into a heat-resistant resin layer from the opening end to the support ring. Since it is covered, the heat resistance of the mouth is particularly excellent. Therefore, thermal shrinkage of the mouth due to hot fill or the like is small, and the sealing property is good.

Further, since the bottle of the present invention can have a seven-layered multilayer structure including three heat-resistant resin layers at the shoulder, it has sufficient heat resistance to apply pasteurizing by hot shower or the like.

Further, since the bottle of the present invention has an ultraviolet absorbing resin layer from substantially the center of the shoulder to the lower end of the trunk,
Beer and other foods and chemicals that are susceptible to ultraviolet rays can be stored and stored for a long period of time, greatly expanding the range of use of polyester bottles.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of a heat-resistant ultraviolet absorbing multilayer bottle of the present invention, and FIG. 2 is a partially enlarged view showing an example of a multilayer structure in a mouth portion and a shoulder portion of the multilayer bottle of FIG. Fig. 3 is a partially enlarged sectional view showing a multilayer structure in a body portion of the multilayer bottle of Fig. 1, and Fig. 4 is an example of a hot runner nozzle used to manufacture a multilayer preform. FIG. 5 is a graph schematically showing a step of manufacturing a multilayer preform, and FIGS. 6 (a) to 6 (d) show a heat-resistant resin and a polyester resin or a heat-resistant resin. FIGS. 7A to 7E are schematic partial cross-sectional views showing a state where a UV-absorbing resin is co-injected. FIGS. 7A to 7E are schematic views showing a state where a multilayer structure is formed by a heat-resistant resin and a polyester resin. FIG. 8 shows a heat-resistant ultraviolet absorbing multilayer of the present invention. It is sectional drawing which shows the stretch blow molding apparatus used for manufacturing a bottle. 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 8 ... UV absorption Resin layer 11 Screw tightening part 12 Support ring part 13 Seal part at mouth end 14 Screw / locking ring part 15 Head pressure applying part 30 Hot runner nozzle 31, 32 Check valve 40 Injection mold 41 Cavity 100 Heat treatment mold for stretch blow molding 101 Mouth mold 102 Shoulder mold 103 Trunk mold 104 Bottom mold 105 Blow mandrel 106 Stretching rods 108,109 Flow passage 110 Sheath heater 111 Holes 113,114,115 Opening 116 Blow mandrel fixing block 117 Stretching rod fixing block 120 Heat resistant ultraviolet ray absorbing multilayer bottle A ₁ , A ₂ , B, C ... hot runner flow path

Continuation of the front page (51) Int.Cl. ⁷ Identification code FI B65D 1/09 B65D 1/00 B // B29L 22:00 (56) References JP-A-64-38230 (JP, A) JP-A-59 JP-A-179342 (JP, A) JP-A 1-294025 (JP, A) JP-A 63-194116 (JP, U) JP-A 54-7939 (JP, U) JP-A 2-8708 (JP, U) (58) Fields surveyed (Int.Cl. ⁷ , DB name) B32B 1/00-35/00 B65D 1/00-1/48 B29C 49/00-49/80

Claims (4)

(57) [Claims] 1. A heat-resistant ultraviolet-absorbing multilayer bottle comprising a polyester layer, a heat-resistant resin layer, and a resin layer having ultraviolet-absorbing properties, comprising: a mouth; a support ring provided at a lower end of the mouth; It has a shoulder part following the support ring, a body part and a bottom part, and the mouth part is at least at the lower part from the outside from the heat resistant resin layer / polyester layer / heat resistant resin layer / polyester layer / heat resistant resin layer / polyester layer / It has a nine-layer structure of a heat-resistant resin layer / polyester layer / a heat-resistant resin layer, and a resin layer having an ultraviolet absorbing property is arranged from the shoulder portion to at least a lower end of the body portion, and on the body portion and the bottom portion. Is a heat-resistant ultraviolet absorbing multilayer bottle in which the heat-resistant resin layer is not substantially formed, wherein the heat-resistant resin layer is made of a mixture of polyarylate and polyethylene terephthalate. And the outermost heat-resistant resin layer of the mouth is substantially continuously formed from the opening end of the mouth to the support ring. A heat-resistant ultraviolet ray absorbing multilayer bottle, which covers an upper surface of the support ring and has substantially no heat-resistant resin on a lower surface of a base portion of the support ring. 2. The heat-resistant ultraviolet absorbing multilayer bottle according to claim 1, wherein three shoulder heat-resistant resin layers are formed on said shoulder portion from said mouth portion. Multi-layer bottle. 3. The heat-resistant ultraviolet ray absorbing multilayer bottle according to claim 1, wherein the proportion of the heat-resistant resin layer increases toward the opening end, and the proportion (weight ratio) of the heat-resistant resin layer is increased. ) Is a heat-resistant UV-absorbing multi-layer bottle characterized in that it is 70% or more in the mouth end seal portion, 40% or more in the screw tightening portion, and 30% or more in the head pressure applying portion. 4. The heat resistant ultraviolet ray absorbing multilayer bottle according to claim 1, wherein the polyester resin is polyethylene terephthalate.