JPH06262670A - Polyester container having drum part partially defferent in degree of crystallization and production thereof - Google Patents

Abstract

PURPOSE:To obtain a thermoplastic polyester container excellent in the combination of heat resistance, appearance characteristics and impact resistance by subjecting the drum part of a container to orientation thermal crystallization as a whole by thermal fixing and highly crystallizing the part to which higher heat resistance must be given to the drum part as compared with other part. CONSTITUTION:In a thermoplastic polyester container 1, the whole of the drum part 4 of the container 1 is subjected to orientation thermal crystallization by stretch molding and thermal fixing and the part requiring higher heat resistance of the drum part 4, that is, the part receiving the stress due to heat and easy to deform thereof is highly crystallized as compared with other part. By this method, since the thermal deformation of this part is prevented and the degree of crystallization of the other part is suppressed to a low level as compared with that of the highly crystallized part, the generation of unevenness due to the so-called sink is eliminated and excellent appearance characteristics can be obtained and the container 1 is more excellent in impact resistance as compared with one highly crystallized as a whole. The cooling time of this container in a mold is short as compared with the one highly crystallized as a whole and the productivity of the container 1 is enhanced.

Description

Detailed Description of the Invention

[0001]

INDUSTRIAL APPLICABILITY The present invention is excellent in a combination of heat resistance, appearance characteristics and impact resistance, and is excellent in heat resistance particularly useful for hot filling of contents or heat sterilization after filling. Regarding a container made of polyester. The present invention further relates to a method for producing the above polyester container with high productivity.

[0002]

2. Description of the Related Art Polyethylene terephthalate (PET)
Biaxially stretched blow molded containers of thermoplastic polyester such as those have excellent transparency and surface gloss, as well as the impact resistance, rigidity and gas barrier properties required for bottles, and are bottled containers for various liquids. Is used as.

However, the polyester container has a drawback that it is inferior in heat resistance, and when used for the purpose of hot filling or heat sterilization of the contents, thermal deformation or shrinkage deformation of volume occurs, and thus biaxially stretched. After molding the blow container, heat setting (heat
Set) is required.

The heat fixing method is disclosed in Japanese Examined Patent Publication No. 60-5660.
As disclosed in Japanese Patent Laid-Open No. 6-62, a method in which a molded product obtained by stretch blow molding is taken out from a blow mold and then held in a mold for heat setting for heat setting, and JP-B-59-62.
As can be seen in Japanese Patent No. 16, a method is known in which heat setting is performed simultaneously with a stretch blow mold in a blow mold. Further, JP-A-57-53326 discloses a method in which heat treatment is performed simultaneously with stretch blow molding in a primary mold, a molded product is taken out, and the molded product is blow molded in a secondary mold without cooling. Have been described.

Japanese Patent Application Laid-Open No. 63-59 filed by the present applicant
No. 513, a blow mold is maintained at a temperature of 100 to 120 ° C., a thermoplastic polyester preform is heated to a specific temperature in relation to its intrinsic viscosity and diethylene glycol content, and within this preform. It is described that a heat-resistant polyester hollow molded article is produced by a one-mold method by blowing hot air at high temperature and stretching the preform at a high speed.

[0006]

The heat-resistant container is deformed by so-called thermal deformation in which the side wall portion of the container is simply deformed by heat, and the internal volume when the container comes into contact with hot contents and is then cooled. There is a reduced pressure deformation that occurs with the change.

In order to prevent deformation under reduced pressure, a recessed panel portion and a bulged pillar portion are provided on the side wall of the container, and deformation due to bulging and denting of the panel portion is utilized to increase and reduce the internal volume. It is generally practiced to absorb and prevent irregular deformation of the container, but if the degree of heat fixation is not sufficient, the panel part will be thermally deformed, resulting in bulging and denting of the panel part. The disadvantage is that the regulation function of the internal volume does not work well.

Therefore, in the conventional heat setting method, a method of raising the temperature of the entire mold to highly crystallize the side wall (body) of the container to be molded has been used.

However, such high temperature heat setting causes a problem that so-called sink marks (concavities and convexities) are generated on the side wall portion of the container, particularly on the bulging portion having a large diameter, and the appearance characteristics of the container are significantly deteriorated. Further, it is also observed that the impact resistance of the polyester is lowered by heat fixing at a high temperature, and that a portion of the container on a business trip is likely to be damaged due to a drop impact or the like.

Further, if the temperature of the entire mold is increased, it takes a long time to cool the molding heat setting container in the conventional heat setting method.
Since the occupation time in the mold becomes long, there is a drawback that productivity is lowered.

Accordingly, it is an object of the present invention to provide a stretch-molding / heat-fixing container of thermoplastic polyester which is excellent in the combination of heat resistance, appearance characteristics and impact resistance, and a method for producing the same.

Another object of the present invention is that the panel portion of the side wall of the container is highly crystallized, and other side wall portions including the pillar portion are in a state of relatively low crystallization. (EN) It is an object to provide a polyester container excellent in heat resistance that does not undergo thermal deformation during filling or the like and does not cause sink marks, and a method for producing the same.

Still another object of the present invention is to provide a method capable of producing a polyester container having the above-mentioned excellent properties with high productivity.

[0014]

According to the present invention, in a heat resistant container produced by stretch blow molding and heat setting of a thermoplastic polyester, the body of the container as a whole is oriented and heat crystallized by heat setting. In addition, the part of the body that should have higher heat resistance is more highly crystallized than other parts, and is made of polyester with a part of different crystallinity. A container is provided.

Further, according to the present invention, a pillar-shaped convex portion, which is formed by stretch blow molding and heat setting of thermoplastic polyester, is located radially outward in the body of the container, and has a short circumference, A plurality of panel-shaped recesses located radially inward and having a long circumference are alternately provided in the circumferential direction via short connecting portions, and a label portion is provided above or below the body portion as necessary. In the heat-resistant container, the body of the container is oriented and crystallized as a whole by heat setting, and the panel-shaped concave portion is highly thermally crystallized as compared with the pillar-shaped convex portion or other portion. There is provided a polyester container having a body part having partially different crystallinity.

Further, according to the present invention, a preheated thermoplastic polyester preform is mounted in a blow mold maintained at a high temperature, and the preform is expanded and stretched in the circumferential direction and is stretched in the axial direction. In a method for producing a polyester container having excellent heat resistance, which comprises stretching and then holding the container in a mold to perform heat fixation, a mold body equipped with a heater is provided separately from the heater of the mold body. Arrangement of a nest equipped with a heater and the surface of which is maintained at a temperature higher than that of the mold body surface, and orientation thermal crystallization of the body of the container to be stretch-blow-molded as a whole and selection of a portion in contact with the nest surface There is provided a method for producing a polyester container, which is characterized by being highly crystallized.

[0017]

In the polyester container of the present invention, the entire body is oriented and thermally crystallized by stretch molding and heat setting.
The portion of the body portion to which higher heat resistance is to be imparted, that is, the portion which is susceptible to deformation due to heat stress is crystallized to a higher degree than other portions. That is, in the body of the container of the present invention,
The degree of crystallinity is partially different, it is easy to receive stress due to heat, and because the part that is easily deformed is highly crystallized,
Thermal deformation of this part is prevented, and the crystallinity of the other part (the part that does not receive a large force even if heat is applied) is suppressed to a low level compared to the highly crystallized part. There is no unevenness due to so-called sink marks, excellent appearance characteristics are obtained, and in comparison with a highly crystallized whole,
The advantage is that it is also excellent in impact resistance. Also,
Also in terms of manufacturing, compared with the case where the whole is highly crystallized, the cooling time in the mold is shorter, the mold occupying time is shortened, and the productivity of the container can be improved. To be done.

According to the present invention, a pillar-shaped convex portion located relatively radially outward and having a short circumferential length and a panel-shaped concave portion relatively located radially inward and having a long circumferential length are provided on the body of the container. And are alternately provided in the circumferential direction via short connecting portions, and are useful for a container in which a label portion is provided above or below the body portion as necessary. By crystallization to a high degree as compared with the label portion, the following advantages are exhibited.

In the container having the above-mentioned structure, the panel portion projects radially outward due to an increase in internal pressure when heated and dents radially inward due to a decrease in internal pressure when cold, so that the above-mentioned reduced pressure deformation is alleviated. However, when the panel portion plastically deforms due to an increase in internal pressure during heating, the panel cannot be dented due to a decrease in internal pressure during cooling, resulting in a situation in which unintended asymmetric deformation occurs in the container. Since the panel portion is highly crystallized, the plastic deformation of the panel portion is prevented even when the internal pressure increases during heating, and the function of smoothly absorbing the reduced pressure deformation by the panel pillar is obtained.

The parts that stand out from the outside of the container are pillar-shaped protrusions or label parts, but in the present invention, the temperature of the mold body in these parts is relatively low and the crystallinity is kept relatively low. Since there is no unevenness due to sink marks (the sink marks are generated by cooling hot things during molding),
The appearance of the container can be improved and its commercial value can be increased. In addition, it is the pillar portion that also acts as a reinforcing rib that receives the most external force such as impact on the container.
In the present invention, since the crystallinity of the pillar portion is suppressed to be low, flexibility is maintained and strong impact resistance can be obtained.

Further, in the manufacturing method of the present invention, a preheated thermoplastic polyester preform is mounted in a blow mold maintained at a high temperature, the preform is expanded and stretched in the circumferential direction, and the preform is axially stretched. It is stretched and stretched, and then the container is held in the mold for heat setting, but the mold body equipped with a heater is equipped with a heater independent of the mold body heater, and the surface is hotter than the mold body surface. Placing a nest that is maintained in is a salient feature.

The temperature of the mold surface and the temperature of the mold surface other than that are controlled by disposing a nest having a heater independent of the heater in the mold body provided with the heater. It is possible to hold the part in contact with the insert surface at a high temperature and heat-set it so that the crystallinity becomes high while orienting and crystallizing the entire body of the container to a predetermined crystallinity. Become.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Since the present invention is particularly useful for manufacturing a container having a panel pillar structure, the present invention will be described below with reference to this example, but the present invention is not limited to this example.

(Container) In FIG. 1 showing a preferred example of the container of the present invention, this heat-set biaxially stretched container 1 has an unstretched mouth / neck portion (neck portion) 2, a truncated cone-shaped shoulder portion 3, and a substantially cylindrical shape. Body 4
And a closed bottom part 5. In this specific example, the body portion 4 is composed of an upper label portion 6 and a lower body portion 7, and a waist portion 8 narrowed to a small diameter is interposed between the label portion 6 and the lower body portion 7.
Exists.

The lower body portion 7 has a pillar-shaped convex portion 9 having a relatively large diameter and a short circumference, and a panel (mirror) concave portion 10 having a relatively small diameter and a long circumference. Short connecting part 11
A large number of them are alternately provided in the circumferential direction via the. The pillar-shaped convex portion 9 extends in the container axial direction (height direction), and therefore the panel-shaped concave portion 10 has a substantially rectangular shape partitioned by the pillar-shaped convex portion 9 with long corners rounded in the container axial direction. Have The panel-shaped concave portion 10 can expand (project) radially outward due to an increase in internal pressure and contract inward (concave) due to a decrease in internal pressure, which has the effect of relaxing the internal pressure change. ing.

In the heat-set stretched polyester container of the present invention, the thickness of the body portion is 0.20 to 1.00 mm, particularly,
The size of the panel-shaped concave portion may vary depending on the size of the container, but the size in the circumferential direction is generally 10 to 50 mm, and the size in the axial direction (height direction) is 40 mm. It is desirable to be within the range of 160 mm to 160 mm. Further, it is preferable that the step difference between the pillar-shaped convex portion having a large diameter and the panel-shaped concave portion having a small diameter, that is, the difference in diameter is within a range of 1 to 8 mm.

Referring to FIG. 4 showing another preferred example of the container of the present invention, this heat-set biaxially stretched container 1 has a hollow shoulder portion 3 having a truncated pyramid shape and a trunk portion 4 having a substantially square or rectangular cross section. It has a prismatic shape. The body portion 4 is composed of an upper portion 6a and a lower portion 7a, and a narrowed waist portion 8 is also present between the both.

4 of each of the upper body 6a and the lower body 7a
A pillar-shaped convex portion 9 having a small area is provided at each corner portion, and a substantially square or rectangular panel (mirror) portion 10 having a large area is provided between the pillar-shaped convex portions.

The internal volume of these containers is 180 to 500.
It is generally in the range of 0 ml.

In the present invention, the thermoplastic polyester constituting the container is a thermoplastic polyester mainly composed of ethylene terephthalate units, for example, polyethylene terephthalate (PET) and a small amount of other glycols such as hexahydroxyrylene glycol as a glycol component. Or modified PET containing a small amount of another dibasic acid component such as isophthalic acid or hexahydroterephthalic acid is used as the dibasic acid component.
These polyesters may be used alone or in the form of a blend with a small amount of other resins such as nylons, polycarbonate or polyarylate, or in the form of a multilayer structure as long as the essence thereof is not impaired.

The intrinsic viscosity (η) of the thermoplastic polyester used is 0.65 dl / g or more, particularly 0.70 to 0.
It is desirable that it is in the range of 90 dl / g and the content of diethylene glycol units is in the range of 1.60% by weight or less, particularly 1.50% by weight or less.

In the container of the present invention, the entire body 4 is oriented thermally crystallized by biaxial stretching and heat setting, and the panel-shaped recess 10 is highly crystallized. The crystallinity (density method) of the panel-shaped recess is 34 to 50%, and particularly preferably 3
It is preferably in the range of 5 to 45%. In addition, the density method crystallinity is based on “Polymer Experimental Science Vol. 17, Polymer Fixed Structure II”, No. 30, published by Kyoritsu Shuppan Co., Ltd. on November 20, 1984.
The formula, as described on page 5,

[Equation 1] Where ρ is the density of the sample (g / cm
³ , 25 ° C.), ρ _a is a completely amorphous density, typically 1.335 g / cm ³ for PET, and ρ _c is a completely crystalline density, typically PET 1.455 g / cm ³ , X _cv
Is the crystallinity (%).

When the crystallinity of the panel-shaped recess is lower than the above range, heat resistance is insufficient such as deformation when heated, while when it exceeds the above range, impact resistance is lowered, This is not preferable because it tends to result in poor appearance. The most preferable range varies depending on the application, but is 34% or more for what is called general heat resistance (85 ° C) and 37% or more for what is called high heat resistance (95 ° C). is there.

On the other hand, the crystallinity of the body other than the panel-shaped recess is generally in the range of 30 to 45%, particularly 33 to 42%, and at least 1% lower than that of the panel-shaped recess, and particularly preferably at least. It preferably has a low crystallinity of 2%. When it is lower than the above range, the heat resistance of the entire container becomes insufficient. On the other hand, when it is higher than the above range, sink marks occur in the container due to insufficient cooling during molding. , Its appearance characteristics are poor and impact resistance is also lowered. Preferably,
From the viewpoint of effectively relieving the reduced-pressure deformation, the pillar-shaped convex portion preferably has a crystallinity intermediate between the label portion and the panel-shaped concave portion, and the pillar-shaped convex portion has a crystallinity of 33 to 45%. The label portion preferably has a crystallinity of 30 to 42%.

(Manufacturing Method) FIG. 2 showing a partial cross sectional side view of an essential part of the biaxially stretched blow and heat fixing mold (cavity mold) used in the present invention and FIG. 3 showing the III-III cross section of FIG. The cavity molds 20, 20 can be opened and closed on the parting surface 20A, and are composed of a mold main body 21 and a panel forming insert 22 arranged on the inner surface side thereof. Inside the cavity mold 20, in relation to the container structure of FIG. 1, the lower neck molding surface 23, the shoulder molding surface 24, the label molding surface 24a, the waist molding surface 25 and the lower surface. Body forming surfaces 26 are formed respectively. An opening 27 for inserting a bottom mold is provided at one end (left end in the figure) of the cavity mold 20, and a bottom mold 29 having a bottoming dome 28 can be put in and out through the opening 27. . Also, at the other end (right end in the figure) of the cavity mold 20, there is an opening 30 for accommodating a portion close to the mouth of the preform (not shown), and the cores are kept in a state where the cavity molds 20 and 20 are opened. A preform (both not shown) that is closely supported by the other end of the mold cavity mold 20 is mounted in the cavity mold.

The mold main body 21 is provided internally with a heater 31 for the main body extending in the axial direction. On the lower body forming surface 26, pillar forming surfaces 32 and nest support seats 33 are alternately arranged in the circumferential direction. Many are arranged.

The panel insert 22 is provided with a heater 34 for heating, which is independent of the heater 31 for the main body, and a lead wire 35 for power supply inside, and the panel forming surface 36 is
The mold body 21 is attached to the mold body 21 by fastening means (not shown) such as bolts so as to be located inside the pillar forming surface 32 of the mold body 21 by a small distance. Thus, the panel forming surface 36 of the insert 22 has the mold body 21.
Is maintained at a temperature higher than that of the pillar forming surface 32.
The step portion 37 between the insert 22 and the pillar forming surface 32 of the mold body forms the connecting portion 11 (FIG. 1) between the panel and the pillar.

According to the manufacturing method of the present invention, a preheated thermoplastic polyester preform is mounted in the mold, and the preform is expanded and stretched in the circumferential direction.
It is stretched in the axial direction and stretched, and then the container is held in a mold for heat setting.

The bottomed preform used for stretch blow molding may be any method known per se, such as injection molding.
It is manufactured by a pipe extrusion method or the like. In the former method, molten polyester is injected to produce a bottomed preform having a mouth and neck corresponding to the final container in an amorphous state. In the latter method, an extruded amorphous pipe is cut, a mouth neck portion is formed by compression molding at one end, and the other end is closed to form a bottomed preform. Generally, it is preferable to manufacture by injection molding. The injection conditions and the like are not particularly limited, but generally, the bottomed preform can be molded at an injection temperature of 260 to 300 ° C. and an injection pressure of 30 to 60 kg / cm ² .

In order to impart heat resistance and rigidity to the neck portion of the thus obtained preform, the neck and neck portion having a screwing portion, a fitting portion, a supporting ring and the like may be crystallized and whitened by heat treatment at the preform stage. On the other hand, in some cases, after completion of the molding of a bottle for which biaxial stretching blow described below is completed, the mouth and neck portion of the unstretched portion is crystallized and whitened.

The bottomed preform is heated at a temperature higher than the glass transition point of the thermoplastic polyester and lower than the thermal crystallization start temperature, or preheated at a temperature higher than the crystallization temperature for a short time. Although the specific preheating temperature varies depending on the composition of the polyester, it is generally 80 to 1 in the case of PET.
A range of 50 ° C, especially 90 to 130 ° C, is suitable.

In the present invention, the surface temperature of the mold body is preferably maintained at 100 to 170 ° C., particularly 110 to 160 ° C. When the heating temperature is lower than the above range, it is not sufficient to remove strain due to stretching, heat resistance is poor, and it is difficult to increase the crystallinity as in the present invention. On the other hand, if this temperature is too high, the impact resistance tends to decrease and the productivity tends to deteriorate.

On the other hand, the surface of the nest is 110 to 190.
It is preferable to maintain the temperature in the range of 120 ° C., particularly 120 to 185 ° C., and at least 3 ° C. or more, preferably 5 ° C. or more higher than the surface of the mold body. If the nesting surface temperature is lower than the above range, it may be difficult to selectively highly crystallize the panel portion, while higher than the above range, in terms of various characteristics of the container, Also in terms of productivity, it tends to be disadvantageous.

Although there is the above-mentioned difference between the surface temperature of the die main body for forming the body and the surface temperature of the nest, it is also understood that the surface temperature of the die main body differs depending on the site. Should be. For example, in the specific example shown in the drawings, the temperature of the pillar portion forming surface may be slightly higher than the temperature of the label forming surface. This is because the temperature of the surface for forming the pillar portion slightly rises due to the effect of heat transfer from the nest heater. Such a temperature gradient is quite effective in alleviating the reduced pressure deformation, but in order to reduce the temperature difference between the pillar portion forming surface and the label portion forming surface,
Insulating material is interposed between the nest and the nest support seat,
Alternatively, it is of course possible to provide a heat shield space.

According to the present invention, a thermoplastic polyester preform preheated to the above temperature is mounted in the blow mold maintained at the above temperature, and the preform is expanded and stretched in the circumferential direction. It is stretched and stretched in the axial direction. In the stretching operation, generally, a pressurized fluid is blown into the preform to perform axial tensile stretching and circumferential expansion stretching with a stretching rod, but the stretching speed at the initial stage of this stretching may be high. Further, prior to the blowing by blowing the high-pressure gas, the pre-blowing can be performed with a fluid having a low pressure. In the present invention, as the pressurizing fluid, unheated air or an inert gas may be used, or heated air or an inert gas may be used. However, when the heated fluid is used, the heat setting time is shortened. There is an advantage that is done.

The pressure of the pressurized fluid used varies depending on the capacity of the final container and the thickness of the preform, but the initial pressure of the gas generally used is 25 kg / cm ² or more, especially 3
It is preferably in the range of 0 to 40 kg / cm ² . Also, the temperature of the fluid is preferably in the range of 20 to 250 ° C.

The stretching ratio in the final container is preferably 5 to 20 times, particularly 7 to 15 times in terms of area ratio, while the axial stretching linear magnification is 1.2 to 4 times, particularly 1.5 to 3 times. The draw ratio in the circumferential direction is preferably 2 to 7 times, more preferably 2.5 to 5 times.

The thermoplastic polyester of the vessel wall of the preform that has been stretch-blown comes into contact with the heated inner surface of the mold, and heat fixation (heat setting) is started. The heat treatment time varies depending on the thickness and temperature of the blow molded product,
This heat setting brings about the above-mentioned crystallinity, and generally speaking, the order of 0.5 to 10 seconds, particularly 1 to 5 seconds is suitable.

After the heat fixing is completed, the pressurized fluid trapped in the molding container in the blow mold is released to the outside of the container, and cold air is introduced into the container to cool it. It is desirable to focus cool air on the panel pillars. The most deformable part of the container when it is taken out from the blow mold is the thin-walled panel / pillar part, and this part is difficult to cool due to heat transfer from the mold surface. In the invention, since the mold temperature is lower than that of the panel portion, the cold air is intensively blown to this portion, so that the deformation at the time of taking out can be prevented.

As the cooling fluid, in addition to various cooled gases such as nitrogen at -40 ° C. to room temperature, air and carbon dioxide gas, a chemically inert liquefied gas such as liquefied nitrogen gas and liquefied carbon dioxide gas is used. Liquefied trichlorofluoromethane gas, liquefied dichlorodifluoromethane gas, and other liquefied aliphatic hydrocarbon gas are also used. This cooling fluid includes
A liquid mist having a large heat of vaporization such as water can also be present together. By using the cooling fluids mentioned above, significantly higher cooling rates can be obtained. However,
According to the present invention, there is an advantage that sufficient cooling is performed in a short time even when using room temperature air.

[0051]

The present invention will be further described in the following examples. Example 1 Polyethylene terephthalate having an intrinsic viscosity (IV) of 0.76 dl / g was injection-molded to have a diameter of 28 mm and a weight of 5.
9 g of a preform was obtained, and the mouth and neck of this preform was heated and thermally crystallized. Using this preform and the cavity mold shown in FIGS. 2 and 3, a container having the shape and structure shown in FIG. 1 was manufactured. Each dimension of the container was set as follows. Inner volume: 1500 ml Bottle height: 305 mm Maximum diameter of lower body: 92 mm Height of lower body: 185 mm Circumferential dimension of panel recess: 32 mm Height of panel recess: 125 mm Circumferential dimension of pillar protrusion : 14 mm Thickness of lower body: 0.4 mm Maximum step between panel and pillar: 5 mm Cavity type mold body surface temperature is set to 154 ° C and panel forming nest surface temperature is set to 177 ° C. A preform that had been preheated to 105 ° C. was attached to the above, and pressurized air (30 kg / cm ² gauge) at room temperature was blown therein to expand and stretch, and at the same time, stretch and stretch with a stretching rod. The maximum stretching ratio in the circumferential direction is 4.5, and the maximum stretching ratio in the axial direction is 2.5.
Set to double. After the blow stretching was started, the container was held in the mold for 3 seconds to perform heat setting, and then room temperature air was circulated in the bottle to complete cooling in 2 seconds. Open the mold,
The bottle taken out was further cooled in air to obtain a product.
Table 1 shows the results of measuring the degree of crystallinity and visually determining the presence or absence of sink marks for each part of this container.

The container of this embodiment has no unevenness such as sink marks on the pillar portion and the label portion and has a good appearance, and
Even during hot filling at 93 ° C., the panel portion including the boundary with the pillar portion was not deformed at all, and no abnormal dent or the like was formed in the body portion of the container even after cooling.

Example 2 In Example 1, the mold surface temperature of the cavity mold was set to 15
A biaxially stretched heat-fixed container was produced in the same manner as in Example 1 except that the temperature of the panel molding insert surface was set to 5 ° C and the temperature of the panel molding nest was set to 160 ° C, and 180 ° C pressurized air was used as the blowing fluid. Table 1 shows the results of measuring the crystallinity of each part of this container.

The container of the present invention has no unevenness such as sink marks on the pillar portion and the label portion, has a good appearance, and
Even during hot filling at 3 ° C, the panel portion including the boundary of the pillar portion was not deformed at all, and even after cooling, no abnormal dent or the like was generated in the body portion of the container.

Example 3 In Example 1, the mold surface temperature of the cavity mold was set to 12
A biaxially stretched heat-fixed container was produced in the same manner as in Example 1 except that the temperature of the panel molding insert surface was set to 5 ° C and 135 ° C. Table 1 shows the results of measuring the crystallinity of each part of this container.

The container of this example has no unevenness such as sink marks on the pillar portion and the label portion and has a good appearance, and
Even during hot filling at 85 ° C., the panel portion including the boundary with the pillar portion was not deformed at all, and no abnormal dent or the like was formed in the body portion of the container even after cooling.

Example 4 Polyethylene terephthalate having an intrinsic viscosity (IV) of 0.76 dl / g was injection-molded to produce a preform having a diameter of 28 mm and a weight of 70 g, and the neck of the mouth was thermally crystallized. Using this preform, a container having the shape and structure shown in FIG. 4 was manufactured. The cavity mold used was one in which a nest equipped with an independent heater separate from the mold body was provided in a portion corresponding to the panel-shaped recess. The mold body was 125 ° C., and the nest was 145 ° C. Set to temperature. The dimensions of the container are as follows. Inner volume: 2000 ml Bottle height: 305 mm Long side of body: 106 mm Short side of body: 87 mm Wall thickness of body: 0.4 mm Preheating temperature of preform, stretching conditions and holding time in the mold are examples. 1, but with a circumferential draw ratio of 4.
The draw ratio was set to 2 and the axial draw ratio was set to 2.2. The results obtained are shown in Table 1.

The container of this example has no unevenness such as sink marks on the pillar portion and the label portion and has a good appearance, and
Even during hot filling at 85 ° C., the panel portion including the boundary with the pillar portion was not deformed at all, and no abnormal dent or the like was generated in the body portion of the container even after cooling.

Comparative Example 1 In the same manner as in Example 1, except that a normal mold having no insert was used and the mold surface temperature of the pillar molding part was set to 137 ° C. and the surface temperature of the panel molding part was set to 137 ° C. A biaxially stretched heat setting container was manufactured in the same manner as in Example 1. The results of measuring the crystallinity of each part of this container are shown in Table 1.
Shown in.

The container of this comparative example had a considerable appearance of unevenness such as sink marks at the boundary portion between the pillar portion and the panel portion, and the appearance was poor.

COMPARATIVE EXAMPLE 2 The procedure of Example 1 was repeated except that an ordinary mold having no insert was used, the mold surface temperature of the pillar molding part was set to 125 ° C., and the surface temperature of the panel molding part was set to 125 ° C. A biaxially stretched heat setting container was manufactured in the same manner as in Example 1. The results of measuring the crystallinity of each part of this container are shown in Table 1.
Shown in.

In the container of this comparative example, unevenness such as sink marks was slightly generated at the boundary portion between the pillar portion and the panel portion, the appearance was somewhat poor, and the panel portion was deformed during hot filling at 85 ° C. Moreover, abnormal dents were found in the body of the container even after cooling.

[0063]

[Table 1]

[0064]

According to the present invention, the entire body is oriented and crystallized by stretch molding and heat setting, and the portion of the body to which heat resistance is to be imparted, that is, the portion which is apt to receive force when heat is applied. By crystallizing to a higher degree than other parts, thermal deformation of the easily deformable part at high temperature is effectively prevented, and at the other part (the part that does not receive large force even if heat is applied) Since the crystallinity is suppressed to a low level compared to the highly crystallized part, there is no unevenness due to so-called sink marks, excellent appearance characteristics are obtained, and the whole is highly crystallized. As a result, it is possible to obtain the advantage that the impact resistance is excellent. Also, in terms of manufacturing, compared to the case where the whole is highly crystallized, the cooling time in the mold is shorter, the mold occupying time is shortened, and the productivity of the container can be improved. Is played.

In particular, when the present invention is applied to a container having a panel / pillar structure, the plastic deformation of the panel portion is prevented even if the internal pressure increases during heating, and the function of smoothly absorbing the reduced pressure deformation by the panel / pillar functions. can get. Further, the part that is noticeable in the appearance of the container is the pillar-shaped convex part or the label part, but in the present invention, since the crystallinity of these parts is kept relatively low, there is no unevenness due to sink marks. , The appearance of the container can be improved and its commercial value can be increased. Further, the external force such as impact on the container acts most on the pillar portion which also functions as the reinforcing rib, but in the present invention, the flexibility is maintained because the crystallinity of the pillar portion is suppressed to a low level. As a result, strong impact resistance can be obtained.

Further, according to the present invention, the temperature of the mold surface and the temperature of the mold surface other than the mold surface are arranged by disposing the nest having the heater independent of the heater in the mold body having the heater. It is possible to control the temperature of each part of the container body, while maintaining the temperature of the part in contact with the nest surface at a high temperature while performing the oriented crystallization of the entire body of the container to a predetermined crystallinity. It becomes possible to fix it.

[Brief description of drawings]

FIG. 1 is a side view showing a preferred example of the container of the present invention.

FIG. 2 is a partial cross-sectional side view showing essential parts of a biaxially stretched blow and heat-fixing mold used in the present invention.

FIG. 3 is a sectional view taken along the line III-III of the mold shown in FIG.

FIG. 4 is a side view showing another preferred example of the container of the present invention.

[Explanation of symbols]

 1 Container 2 Mouth Neck (Neck) 3 Shoulder 4 Body 5 Bottom 6 Label 9 Pillar Convex 10 Panel (Mirror) Recess 20 Cavity 21 Mold Main Body 22 Nest 29 Bottom 31 Heater 34 for Heating heater

Claims (12)

[Claims] 1. A heat-resistant container produced by stretch blow molding of thermoplastic polyester and heat-setting, wherein at least the body of the container is oriented and thermally crystallized by heat-setting as a whole, and the body has higher heat resistance. A polyester container provided with a body part having a partially different crystallinity, characterized in that the part to be provided with is crystallized to a higher degree than other parts. 2. The highly crystallized portion of the body is 3
The polyester container according to claim 1, which has a crystallinity of 3% or more and a crystallinity higher than that of the other parts of the body portion by at least 1%. 3. The polyester container according to claim 1 or 2, wherein the portion of the body portion to which higher heat resistance is to be applied is a portion which is easily deformed under stress due to heat. 4. The highly crystallized body portion is a panel portion which can be projected radially outward by an increase in internal pressure and can be recessed radially inward by a decrease in internal pressure. Alternatively, the polyester container described in 2. 5. A pillar-shaped convex portion, which is formed by stretch blow molding of thermoplastic polyester and is heat-fixed, is located relatively radially outward on the body of the container, and has a short circumference, and relatively inner diameter. A plurality of panel-shaped recesses located in the opposite direction and having a long circumference are alternately provided in the circumferential direction via short connecting portions, and the panel-shaped recesses are highly crystallized as compared with the pillar-shaped projections. A polyester container provided with a body part having a partially different crystallinity. 6. A pillar-shaped convex portion, which is formed by stretch blow molding and thermosetting of a thermoplastic polyester and is located relatively radially outward and has a short circumferential length, at least at a lower portion of a body of a container. A plurality of panel-shaped recesses located radially inward and having a long circumference are alternately provided in the circumferential direction via short connecting portions, and a label portion is provided above or below the body portion as necessary. In the heat-resistant container, at least the body of the container is oriented and thermally crystallized by heat setting as a whole, and the panel-shaped concave portion is highly crystallized as compared with the pillar-shaped convex portion or the label portion. A polyester container provided with a body part having a partially different crystallinity. 7. The panel-shaped concave portion of the body portion has a crystallinity of 34 to 50% and the pillar-shaped convex portion of the body portion is 30 to 45.
% Crystallinity lower than that of the panel-shaped recess.
Or the polyester container described in 6. 8. The polyester container according to claim 6, wherein the label portion has a crystallinity of 30 to 43% and has a lower crystallinity than that of the panel-shaped recess. 9. A preheated thermoplastic polyester preform is mounted in a blow mold maintained at a high temperature, and the preform is expanded and stretched in the circumferential direction, and
In a method for producing a polyester container having excellent heat resistance, which comprises pulling and stretching in the axial direction, and then holding the container in a mold to perform heat fixation, in a mold body equipped with a mold heater, A heater independent of the heater of (1) and the surface of which is maintained at a temperature higher than that of the mold body surface is arranged, and the body of the container to be stretch-blow molded is oriented and thermally crystallized as a whole, and the surface of the nest is formed. A process for producing a polyester container, which is characterized by selectively highly crystallizing a portion that comes into contact with. 10. The mold body has pillar-forming surfaces and nest support seats alternately arranged in the circumferential direction on the inner surface of the mold body, and the panel-forming nest is formed on the support seat from the pillar-forming surface. 10. The manufacturing method according to claim 9, which is also provided so as to project inward. 11. The manufacturing method according to claim 10, wherein a heat insulating material is provided between the panel forming insert and the insert supporting seat or a space for heat insulation is provided. 12. The surface of the mold body is 100 to 17
Maintain a temperature of 0 ° C. while maintaining the nesting surface between 110 and 19
Within the range of 0 ℃ and at least 3 ℃ from the surface of the mold body
The method according to claim 9 or 10, which is maintained at a high temperature.