JPH0535666B2 - - Google Patents

Description

[Detailed description of the invention]

This invention relates to the production of hollow biaxially oriented heat-set partially crystalline articles, particularly articles made of poly(ethylene) terephthalate. Description of the Prior Art It was previously known that the thermal stability and barrier properties of poly(ethylene) terephthalate oriented blow molded containers were significantly increased by heat setting. A typical heat setting method is described in U.S. Patent No.
Nos. 4476170, 4512948 and 4522779. U.S. Pat. Nos. 4,476,170 and 4,512,948 disclose poly(ethylene) terephthalate oriented heatset blow molded container products and methods of making the same.
In that method, the preform, preheated to a temperature suitable for orientation, is biaxially stretched in the blow molding, and then, while the hollow container is still in contact with the walls of the blow mold, the container is further stretched. high preferably
The container maintains its shape when not pressurized while being heat set to an elevated heat set temperature in the range 200°-250°C (excluding the neck) and while the container is still under anti-shrinkage pressure above atmospheric pressure. do
Cooled in the mold to a temperature not lower than 100°C. It is also specifically disclosed that this cooling step can be carried out in air outside the mold while maintaining internal pressure. According to these patents,
Higher shrinkage onset temperatures are obtained when the heat set temperature of the hot mold is in the range 220-250°C and the quench temperature is not lower than 100°C. U.S. Pat. No. 4,522,779 discloses an improved plastic container and method for making the same. According to a first embodiment thereof, the container is blow molded in a first hot blow mold and then shaped to a larger size in a second cold mold having a larger volume than the first hot mold. Re-infused. Such containers are noted to have improved physical properties and, in particular, very high hoop yield stresses. However, using larger volume cold molds substantially reduces thermal stability. In a second embodiment, the container is blown in a hot blow mold, then blown again to a larger size in a second hot blow mold, and
The area of the second mold is then blown, and the container is removed from the second hot mold and transferred to a third cold mold, where it is cooled to room temperature while maintaining the internal pressure. In yet another embodiment, the container is blow molded in a first hot mold, reblown in a second hot mold, and then the second mold is cooled to cool the container. US Patent No. 4385089 (UK Patent Specification No.
No. 1604203) relates to heat-set biaxially oriented hollow articles, in which the preform or parison is heated to at least a biaxially oriented temperature, which is higher than the minimum oriented temperature;
It is stated that it must be maintained in close contact with a hot mold at temperatures up to 40°C. In another embodiment, the resulting formed hollow product is gradually cooled to 10-30°C by introducing cooling steam or spray into the hollow product.
After the temperature drops, the cooling steam is cut off and the mold is opened. In other embodiments, the heat set product is allowed to deflate and then reblown in the same hot mold or in a separate cooled mold. This patent requires a heat set temperature of 40°C above the orientation temperature, limiting thermal stability and barrier properties. According to this patent, the temperature of the hot mold must be maintained between 30 DEG and 50 DEG C. above the minimum orientation temperature of the plastic material. Otherwise, production speed may be reduced, cosmetic defects such as large deformation and shrinkage after demolding, problems inherent in heating the mold to a very high temperature and keeping it at that temperature, impairing transparency, etc. It is stated that there are many disadvantages such as the risk of crystallization. Furthermore, according to this prior patent, extreme shrinkage must be avoided and a temperature drop of typically 10-30°C must be achieved. Accordingly, such methods do not provide sufficient heat set to produce thermal stability at higher temperatures, such as is required when filling containers with various products. In addition, such methods are unable to obtain the high degree of crystallinity and resulting high barrier properties required for certain products. U.S. Pat. No. 4,039,641 discloses a method for making liquid-filled heat-set biaxially oriented poly(ethylene) terephthalate bottles, in which
The parison was expanded in a mold at a temperature in the range of 130-220°C, maintained in contact with the mold with a pressurized gas such as carbon dioxide, and the pressurized gas was cooled to about 0-5°C. Cool the crystallized bottle by replacing with cooling liquid. The liquid may be a liquid packaged in a container. Such methods have substantially reduced cycle times given the need to introduce and then remove the liquid, as if the liquid were not packaged in a container. Furthermore,
Utilizing the liquid within the container to cool the container limits the amount of heat that can be extracted from the container. This is because the heat transfer coefficient is small.
A lower heat transfer coefficient also means that it takes longer to extract heat. In addition, filling the container with a limited amount of liquid equal to the volume of the container limits the amount of heat that can be extracted from the container to the amount of heat transferred to this limited amount of liquid. U.S. Pat. No. 28,497 discloses a method and apparatus for reducing molding cycle times in conventional blow molding processes, in which a heated parison is placed in a blow mold using a gas such as carbon dioxide gas. and then subsequently internally cooled with liquid carbonic acid. The product is self-supporting
The product is cooled until it reaches (sustaining) temperature, degassed to atmospheric pressure, the mold is opened, and the product is removed from the mold. This patent does not address biaxially oriented products or heat setting of biaxially oriented products. None of the prior art recognizes or teaches that in order to obtain a self-supporting biaxially oriented heat-set container as in the present invention, it is necessary to continue cooling by circulating liquid carbon dioxide after opening the mold. There is nothing I did. SUMMARY OF THE INVENTION It is therefore among the objects of the present invention to provide a process for the production of partially crystalline biaxially oriented heat-set hollow plastic containers with particularly low cycle times, which comprises oval shaped containers. This allows for the manufacture of heat-set containers of complex shapes, including small-capital investment, easy-to-maintain, and low-cost molding tools. The present invention provides a method for manufacturing partially crystalline, biaxially oriented, heat-set hollow plastic containers from hollow parisons having open ends and closed ends, wherein the open end of the plastic parison is engaged at a temperature within the molecular orientation temperature range. closing the hot parison in a hot mold, the mold being at a heat set temperature, and expanding the plastic parison in the hot mold by internal pressure to induce biaxial orientation of the plastic parison; The internal pressure forces the plastic parison into intimate contact with the hot mold for a sufficient period of time to induce partial crystallization in the biaxially oriented container. while maintaining contact between the biaxially oriented container and displacing the blow molding fluid while closing the hot mold for a period of time;
A cooling fluid, such as liquid carbonic acid, is continuously introduced into the biaxially oriented vessel and the cooling fluid is continuously removed from the vessel until the vessel is sufficiently cooled to prevent significant shrinkage. The method of manufacture comprises opening the hot mold while continuing to introduce, circulate, and remove a cooling fluid for a defined period of time, and finally peeling off the container. More specifically, the present invention provides a method for producing partially crystalline, biaxially oriented heat-set plastic containers from hollow parisons having open ends and closed ends. and placing the parison into a hot mold, the mold being at a heat set temperature, and expanding the parison within the blow mold to the shape of the container by a blow molding fluid. for a sufficient time to induce biaxial orientation of the parison and force it into intimate contact with the blow mold, and also to induce partial crystallization of the plastic material. maintaining said contact by internal pressurization by said blow molding fluid, discharging said blow molding fluid, and simultaneously introducing a cooling fluid to cool said container so that said container is connected to said blow mold. A method of manufacturing a plastic container comprising removing the plastic container from the mold and then further cooling the container outside the blow mold with the cooling fluid, wherein the condition changes when introduced into the blow mold. said cooling is carried out using a cooling fluid having properties such that said cooling fluid is continuously circulated throughout said container, at a point at which the pressure of said cooling fluid prevents contraction of said container. The method of manufacturing a plastic container further comprises: removing the container from the blow mold; and continuing to circulate the cooling fluid until the container becomes self-supporting. . DESCRIPTION OF THE PREFERRED EMBODIMENTS Illustrated with reference to FIG. 1, a method of manufacturing a partially crystalline biaxially oriented heat-set hollow plastic container from a hollow parison having an open end and a closed end comprises: heating to a temperature within the molecular orientation temperature range; Attach the open end of the plastic parison P to a neck clamp (step A), seal the hot parison in a hot mold M at a heat set temperature, and press the plastic parison inside the hot mold M by internal pressure. expanding to induce biaxial orientation of the plastic parison and forcing the plastic parison into intimate contact and conformity with the hot mold M to induce partial crystallization in the biaxially oriented container; Maintaining contact between the mold M and the biaxially oriented vessel for a sufficient period of time by such internal pressurization (step B), and directing a cooling fluid, such as liquid carbonic acid, into the biaxially oriented vessel. The blow molding fluid is removed while being continuously introduced into the mold, while the cooling fluid is continuously circulated and removed from the container while the hot mold is closed for a period of time (Step C), and significant Continue to introduce cooling fluid for a predetermined period of time until the container is sufficiently cooled to prevent shrinkage, and continue to circulate and continuously remove the cooling fluid from the hot mold. (Step D), and finally remove the container. It has been found to be important to introduce the cooling fluid medium over the entire inner surface of the container, preferably with the exception of the stopper, preferably in a uniform manner so that adequate cooling can be achieved. Therefore, the location of the nozzle for introducing the cooling medium is as important as the nozzle fabrication. 2, 3 and 4, the preferred nozzle N includes a first plurality of radially extending and circumferentially spaced orifices 1.
0, a second set of circumferentially spaced orifices 11 extending radially downwardly and axially towards the neck of the vessel C, and radially towards the bottom of the vessel C. and a third set of circumferentially spaced orifices 12 extending in the axial direction. With reference to FIG. 2, the nozzle N is a hollow tube adapted to be moved into the mold through the neck forming part of the mold by the action of the cylinder 14 cooperating with the piston 15 on the rod 13. It is located on the extension rod 13. Insufflation pressure is supplied through a three-way valve 16 which directs an insufflation fluid, e.g. air or nitrogen, through a passage 17 to a gap 18 around the hollow rod 13.
The parison P is supplied to a nozzle N which blow-moulds it to form a container C. At this time, the nozzle N is moved to a desired position within the container C. Alternatively, the nozzle N can be moved to a desired position within the container C to cool the container C, with the nozzle N being an elongated rod for axially elongating the parison before or simultaneously with the introduction of the blowing fluid. Rod 13 that can be retracted to lead to
A nozzle N may be used at the end. The injection fluid is initially at low pressure, e.g. 4.9-14Kg/cm ² (70-200p.s.
i.), then for example 10.5-24.5Kg/cm ² (150
−350 p.si) and maintain contact between the container and the mold surface. After the crystallization or heat set time is over,
Valve 16 is operative to vent the insufflation fluid via passageway 17 to the atmosphere. A cooling fluid, for example carbon dioxide, is supplied into the blow molding container C from a source S via a line 19 and a solenoid operated valve 20 through the passages and nozzles of the hollow rod 13, and also continuously from around the nozzle N. It is discharged via passage 17. A plastic tube 21 made of nylon or the like is fed inside the rod 13;
Freezing or blockage of the passage of the hollow rod 13 is minimized. The cooling medium used here consists of liquid carbon dioxide, liquid nitrogen, or a mixture of water vapor and subzero temperature air. A preferred cooling fluid comprises liquid carbonic acid;
This is introduced at above atmospheric pressure and expanded through the opening or orifice of nozzle N, and due to the temperature difference between the container and carbon dioxide, and the carbon dioxide changing from liquid or solid state to gaseous state at low pressure inside the container. Utilizes the latent heat of evaporation. During cooling, the pressure within the container is slightly above atmospheric pressure. If the cooling medium is a mixture of water mist and sub-zero temperature air, it also expands upon passing through the opening of the nozzle N and first forms a solid state of snow or ice;
It then evaporates to a gaseous state to facilitate cooling. If the cooling medium is liquid nitrogen, the heat transfer or cooling effect is performed by latent heat evaporation from the liquid to the gaseous state and subsequent heat transfer based on the temperature difference between the gaseous state and the container. Each step in the operation consists of: That is,
Attach the open end of the plastic parison P heated to a temperature within the molecular orientation temperature range (Step A), seal the hollow parison in a hot mold M at a heat set temperature, and place the plastic parison in the hot mold M. inducing biaxial orientation of the plastic parison by internal pressurization in the chamber, forcing the plastic parison into intimate contact with and mating with the hot mold M, and forming the biaxially oriented container. contact between the mold M and the biaxially oriented container is maintained by such internal pressurization for a time sufficient to induce partial crystallization in (step B); cooling, such as in liquid carbonic acid; Blow molding fluid is removed while fluid is continuously introduced into the biaxially oriented container, while the cooling fluid is continuously circulated while the hot mold is closed for a period of time, and the blow molding fluid is continuously introduced from the container. (Step C), continuing the introduction of cooling fluid for a predetermined period of time until the container has cooled sufficiently to prevent significant shrinkage, continuously circulating the cooling fluid, and continuously removing the cooling fluid from the container. Open the mold and heat it while removing
(Step D) Finally, take out the container. In the method version according to FIG. 7, the mold M ₁ is a three-section mold consisting of a mold part 40 that closes around a mold base part 41 . The mold base portion 41 is shaped to form the bottom of the container. In this method, the mold base is axially movable by a fluid cylinder 42 via a piston rod 43, the mold _M1 is open and a cooling fluid is continuously introduced into the container, circulated and continuously When removed or expelled, the bottom of the container
It is held in place by the mold base portion 41 of the mold, as shown in position D in the figure. After the introduction of the cooling fluid has ended, the mold base part 41 is retracted axially outwards and the container is removed by opening the neck clamp 22. This method of using a movable base portion is particularly useful when the bottom of the container is shaped such that the molded container can stand on its own. It will be appreciated that introducing carbon dioxide or a similar cooling fluid acts to reduce the ambient temperature of the container while the mold is closed. When the mold is open, the continuously flowing positive pressure of carbon dioxide not only prevents the container from collapsing, but also continues to cool the container from within, thereby keeping the container cool until it achieves self-supporting conditions. continues to reduce the average temperature of If the heat set temperature is about 200°C or higher, the average temperature of the container when the mold is opened will necessarily be higher, and if the cooling time continues for an excessive period of time at positive carbon dioxide pressure, the container will may slightly increase the volume. To prevent such growth, if necessary, reduce the amount of time the CO2 supply is applied after opening the mold and continue cooling until the container is self-supporting, before any undesirable growth occurs. It will have to be controlled so that cooling ends at Another reason to minimize cooling time is that otherwise cycle times increase and cooling fluid consumption substantially increases, thus negatively impacting productivity and costs. It should be understood that volume growth or expansion is minimal in any case and the above considerations only apply if it is desired that the container does not substantially change in volume from the blown container. be. The method of the present invention is applicable to polymers that can be biaxially oriented and can be blow molded at the orientation temperature and then heat set at a higher heat set temperature to provide a hollow article with improved barrier properties that is thermally stable. . The methods and products of the invention particularly have an intrinsic viscosity of at least
0.6 for poly(ethylene) terephthalate polymers. The poly(ethylene) terephthalate polymers useful in this invention contain repeating units of ethylene terephthalate, the balance being a copolymer of ethylene terephthalate with a small amount of an ester-forming component, where up to about 10 mole percent of the copolymer is , the glycol moiety during the preparation of the copolymer is butane-1,4
-Diol; diethylene glycol; propane-
Substituted with one selected from 1,3-diol; poly(tetramethylene glycol); poly(ethylene glycol); poly(propylene glycol); 1,4-hydroxymethylcyclohexane, etc., or alternatively a copolymer Up to 10 mole percent of the acid moiety (terephthalic acid) in the preparation of isophthalic acid; naphthalene-1,4- or 2,6-dicarboxylic acid; adipic acid; sebacic acid;
It is prepared from monomeric units substituted with dicarboxylic acids and the like. Of course, the poly(ethylene) terephthalate polymer can contain various additives that do not adversely affect the polymer. For example, certain such additives may include stabilizers, such as antioxidants, or UV screening agents, extrusion aids, additives to make the polymer more susceptible to decomposition or flammability, dyes or pigments. It is. Additionally, small amounts of crosslinking or branching agents, such as those disclosed in US Pat. No. 4,188,357, can be incorporated to increase the melt strength of the poly(ethylene) terephthalate. The method comprises an orientable and heat settable polymer and another polymer providing favorable barrier properties, the orientable and heat settable polymer being a major portion of the total weight, preferably at least 70% of the total weight. It can also be applied to multilayer parisons consisting of %. Typical examples include: poly(ethylene) terephthalate and copolyesters; poly(ethylene) terephthalate, nylon and copolyesters; poly(ethylene) terephthalate,
Adhesives, nylon, glue and poly(ethylene)
It is terephthalate. The method also includes blending poly(ethylene) terephthalate with a polymer that provides favorable barrier properties such that the poly(ethylene) terephthalate is a major portion of the total weight, preferably at least at least the total weight.
It is also applicable to formulations consisting of 70%. Accordingly, as used herein and in the claims, the term poly(ethylene) terephthalate is intended to include the poly(ethylene) terephthalate-containing materials described above. The following parameters yield satisfactory results for poly(ethylene) terephthalate: Orientation temperature 80-110°C Heat-set temperature 120-250°C Heat-set time 0.5-10 sec. Cooling time 1.0-10 sec. Mold opening delay 0.5- 9.5 sec. Preferred parameter ranges are heat set temperature in the range 180-230°C, heat set time in the range 1-5 seconds, mold opening delay in the range 0.5-5 seconds, and mold opening in the range 0.8-1.2 seconds. This is the subsequent cooling. The present invention is suitable for complex containers such as non-cylindrical containers, e.g. oval in cross-section, consisting of two or more cylindrical parts of different cross-sectional areas, cylindrical parts, ramps, grooves, ribs. It is particularly useful in the manufacture of containers incorporating other similar combinations. 5 and 6, for example, container 3
0 consists of eight vertical grooves 31, three horizontal truncated conical ribs 32 and an inverted truncated conical shoulder 33. In the test results shown below, the container was
The shape was as shown in FIG. 6 and FIG. 6, and the removal of the blown fluid and the introduction of the cooling fluid were performed at the same time. The mold opening delay time was measured from the beginning of the evacuation and introduction of the cooling fluid. The bottom temperature of the mold was lower than the rest in order to heat set the thicker bottom less than the rest of the container. Also, in the test results below, the container is I.
It was made of V.0.80 poly(ethylene) terephthalate. The axial stretch ratio is 1.6X, the hoop stretch ratio is in the range of 4.8X to 5.3X in the area of the groove 31,
3.4X to 5.3X in the rib 32 area, 3.4X in the shoulder 33
It was within the range of ~3.66X. In connection with illustrating how important nozzle positioning is when manufacturing complex containers, the test was carried out with a height of 24.1 cm (91/2 inches) and a non-shrinkage satisfactory total capacity of approximately 1490 c. .c. The containers shown in Figures 5 and 6 were made. A summary of the test results is shown in Table A below.

[Table] Distance, inches
Total capacity, cc 1475.7 1481.0 1476.0 1478.5
When the nozzle position was between 5.1 and 8.9 cm (2 and 31/2 inches) from the bottom, a satisfactory container with clear contours and low post-molding shrinkage (full capacity) was obtained. I understand. It is therefore necessary to construct and position the nozzle so that the cooling medium cools all parts of the container. Table B summarizes a series of tests on containers made with varying opening delays and carbon dioxide cooling times.

【table】

[Table] From bottle number 4B in Table B, it can be seen that when the opening delay and cooling time are the same, the molded container is severely crushed. Furthermore, if the difference between the mold opening delay time and the carbon dioxide supply time is less than 0.5 seconds, crushing or loss of sharpness will occur in bottle numbers 4B, 7B,
occurs, as seen in 10B. In the case of bottle 15B, the combination of opening delay and cooling time was not adequate to cool the container to a self-supporting condition. This can be improved by reducing the mold opening delay time, as seen in bottle number 11B compared to bottle number 10B, or bottle number 8B compared to bottle number 7B. Or bottle number
The cooling time can also be increased as seen in bottle numbers 14B and 16B compared to 15B. The remaining containers were satisfactory within the intended total capacity and general appearance. Table C shows a series of tests at different heat sets or crystallization temperatures but with the same mold opening delay and CO ₂ feed time.

【table】

[Table] Distance, inches

Full capacity, cc 1366.3 1408.0 1408.0
1362.6 1391.9 1391.4 1340.9 1329.0 1355.2
All containers were severely deformed and crushed and were unacceptable. As can be seen in each example, the resulting containers were severely deformed and crushed and were not commercially acceptable. Additional testing has shown that similar opening delays and cooling times result in similar containers with significantly reduced sharpness. Therefore, it can be seen that in order to obtain satisfactory results, it is essential to continue supplying carbon dioxide even after the mold is opened. Table D below summarizes the properties of the representative examples of containers shown in FIGS. 5 and 6.

[Table] From the above table, it can be seen that the mechanical properties and improved density are satisfactory. The intrinsic viscosity here refers to the weight ratio at 25℃.
Viscosity measured in 60/40 phenol/tetrachloroethane solution. Density
Mechanical properties were determined as specified in ASTM Standard D-638. Table E below shows the shrinkage onset results. It can be seen that the onset of shrinkage is substantially increased by the method of forming the containers shown in Figures 5 and 6 over similar containers formed without heat setting.Table E Shrinkage Onset Heatset Temperature = 228°C Heat set time = 5 seconds CO ₂ time = 5 seconds Container shrinkage begins °C Heat set 110°C No heat set 50°C Except that the sample was cut from the side wall of the bottle.
The above shrinkage start temperatures are Brady and
Jabarin's "Thermal Treatment"
of Cold-Formed Poly (Vinyl Chloride)
"Thermal Treatment of Cold-Formed Poly(vinyl Chloride) Polymer Engineering and Science", Vol. 17, No.
9, PP.686-90, published September 1977. Cut samples were not heat treated prior to testing. Table F shows the results of tests conducted at relatively low heat set times. Table F bottle number 1F Crystallization Temperature, °C 225 Time, seconds 3 Bottom temperature, °C132 Mold opening delay, seconds 2.5 CO ₂ On Time, seconds
3.5 Nozzle position, distance from bottom, inches 31/2 Total capacity, cc 1490.0 The above results show that satisfactory containers can be obtained by following a method with relatively low heat-setting times. It is also seen that a method has been provided for making biaxially oriented heat set containers with high onset shrinkage temperatures. It has been discovered in testing various heat-setting methods embodying the present invention that the resulting containers can be easily cooled to temperatures substantially below 100°C and are easily processed by operators practicing the method. can be touched or touched. Observations from known light scattering tests indicate that containers made according to the method of the present application have more internal structure within the container body than containers obtained by the preceding heat-setting method, which requires a longer period of time to cool down the container after heat-setting. This indicates that it appears to have a uniform crystal size distribution. It is believed that this more uniform crystal size distribution is due to the rapid cooling achieved by the method of the present invention. A summary of the working order used according to this method is given below. 1. Heat the parison to orientation temperature (90°-100°C). 2 Soak the parison for a period of time to equilibrate its internal and external temperatures. 3 Move the parison to the blow molding position. 4 Close the mold. 5. Blow mold the parison and heat set it for a certain period of time. 6 Vent the container. 7. Introduce liquefied CO ₂ while evacuating the container. 8 Open the mold and continue CO ₂ injection. 9 Complete CO ₂ injection. 10 Remove the container from the clamp and take it out. If the container has a complex or self-supporting bottom, a mold base is provided which is cooled while the mold is opened and the mold base engages the bottom of the container. It maintains contact with the bottom of the container as fluid is continuously poured into the interior of the container. Movable mold bases are also used for containers with hemispherical bottoms to stabilize the container while the mold is opened and cooling fluid is poured. It can thus be seen from the foregoing that the invention provides a method and apparatus for manufacturing partially crystalline, biaxially oriented heat-set hollow plastic containers;
The containers manufactured by this method have low shrinkage after molding, high density, high shrinkage onset temperature and satisfactory mechanical properties, and the manufacturing method and equipment have a fairly low cycle time. Heat-set containers of complex shapes, including oval containers, can be manufactured in a timely manner, with low capital investment, easy maintenance, and the forming tools used are relatively inexpensive. Can be easily adapted to conventional machines due to cost.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing successive steps in a method embodying the invention. FIG. 2 is a partial schematic diagram of a portion of the apparatus utilized in the present method. FIG. 3 is an enlarged partial view of the nozzle used in this device. FIG. 4 is a cross-sectional view taken along line 4--4 of FIG. FIG. 5 is a front view of a container made in accordance with the present invention. FIG. 6 is a bottom view of the container shown in FIG. 5. FIG. 7 is a schematic diagram showing successive steps in a modified method embodying the invention. DESCRIPTION OF SYMBOLS 10...First orifice, 11...Second orifice, 12...Third orifice, 13...Extension rod, 14...Cylinder, 15...Piston, 16...Three-way valve, 17...Passage, 18...Gap, 19...Pipe Road, 2
0...Solenoid operated valve, 21...Plastic pipe, 22...
Neck clamp, 31... Vertical groove, 32... Rib, 3
3...Shoulder, 41...Mold base, 42...Fluid cylinder, 43...Piston rod, M...Mold, N...
Nozzle, P...parison.

Claims (1)

[Claims] 1. A hollow parison having an open end and a closed end,
To produce a partially crystalline, biaxially oriented heat-set plastic container, the open ends of the parison are engaged at a temperature within the molecular orientation temperature range, the parison is placed in a thermal mold, and the mold is at a heat-set temperature. inducing a biaxial orientation of the parison by expanding the parison in the blow mold to the shape of the container with a blow molding fluid; and forcing the parison. and maintaining said contact by said internal pressurization by said blow molding fluid for a sufficient period of time to induce partial crystallization of said plastic material. , discharging the blow molding fluid and simultaneously introducing a cooling fluid to cool the container, removing the container from the blow mold, and then cooling the container outside the blow mold. The method for manufacturing a plastic container comprising further cooling with a fluid, wherein the cooling is carried out using a cooling fluid that has a property of changing state when introduced into the blow mold, and the cooling fluid is continuously circulated throughout the container; and at a time when the pressure of the cooling fluid prevents shrinkage of the container, the container is removed from the blow mold, and the container is free-standing. A method of manufacturing a plastic container, characterized in that the cooling fluid is continued to be circulated for a period of time until the temperature of the plastic container reaches 1. 2. A method as claimed in claim 1, in which a nozzle is used for the introduction of the cooling fluid, and the cooling fluid is introduced radially and axially onto substantially all internal surfaces of the container. 3 Poly(ethylene) terephthalate was used for the formation of the parison, and the molding operation was performed according to the following parameters: Orientation temperature 80-110°C Heat-set temperature 120-250°C Heat-set time 0.5-10 seconds Cooling time 1.0-10 seconds Mold The method according to claim 1 or 2, wherein the mold opening delay is within the range of 0.5 to 9.5 seconds. 4 The following parameters, heat set temperature: 180-230°C, heat set time: 1-5 seconds, mold opening delay: 0.5-5 seconds, cooling time after opening the blow mold, within the range of 0.8-1.2 seconds. The method described in Scope No. 3. 5. The method according to any one of claims 1 to 4, wherein liquid carbon dioxide or liquid nitrogen or a mixture of air at zero temperature and water mist is used as the cooling fluid. 6 From a hollow parison with an open end and a closed end,
A method of manufacturing a partially crystal biaxially oriented heat-set hollow plastic container, comprising: a separation mold engaging the open end of a plastic parison container at a temperature within a molecular orientation temperature range and separating the hot parison from a splittable mold; closing a splittable hot mold having a base, the mold being at a heat set temperature, and expanding the plastic parison within the hot mold by internal pressure to induce biaxial orientation of the plastic parison. , forcing the plastic parison into intimate contact with and conforming to the hot mold by the internal pressure for a sufficient period of time to induce partial crystallization into the biaxially oriented container. Maintaining contact between the biaxially oriented container and displacing the blow molding fluid, while simultaneously closing the hot mold for a period of time, changing conditions upon introduction into the mold such as liquid carbonate continuously introducing cooling fluid into the biaxially oriented container and continuously removing cooling fluid from the container to maintain engagement of the mold base with the bottom of the container and prevent significant shrinkage; , opening the hot mold while continuing to introduce a cooling fluid for a predetermined period of time until the container is sufficiently cooled, and finally peeling off the container. 7. A claim that accomplishes the step of introducing the cooling fluid by a nozzle located axially within the blow-molded container such that the cooling fluid is introduced over substantially the entire interior surface of the container. The method described in item 6. 8 The plastic parison is poly(ethylene)
7. The method of claim 6, wherein the material is made of terephthalate. 9. The method according to claim 8, wherein the temperature of the heat set of the mold is within the range of 120°C to 250°C. 10 The following parameters: Orientation temperature 80-110°C Heat-setting temperature 120-250°C Cooling time 1.0-10 seconds Heat-setting time 0.5-10 seconds Mold opening delay 0.5-9.5 seconds Claim 6 The method described in section. 11 The heat set temperature is within the range of 180-230°C, the heat set time is within the range of 1-5 seconds, the mold opening delay is within the range of 0.5-5 seconds,
11. The method of claim 10, wherein the cooling after opening is within the range of 0.8-1.2 seconds. 12. The method of claim 11, wherein the heat set temperature is about 225°C and the heat set time is about 3 seconds. 13. The method of claim 6, wherein the cooling fluid is selected from the group consisting of liquid carbon dioxide, liquid nitrogen, or a mixture of zero temperature air and water mist. 14. The method of claim 6, wherein the cooling fluid comprises liquid carbonic acid. 15 The mold includes a divisible mold and a separate mold base around which the divisible mold is closed, and after the mold is opened, the mold is cooled while being opened. 7. The method of claim 6, including the step of maintaining engagement between the mold base and the container while fluid is successively introduced and removed from the container. 16. The method of claim 15, wherein the mold has a cavity defining a complex container. 17. The method of claim 6, wherein the mold has a cavity defining a complex container.