JP2005313975A - Synthetic resin bottle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a synthetic resin bottle that can sufficiently be used for application requiring high-temperature heat processing, particularly as for retort food, by creating a barrel wall structure which fully exhibits a pressure absorbing function and a vacuum absorbing function and can smoothly be deformed while copying with a great change from an increase in pressure to a decrease in pressure. <P>SOLUTION: The barrel of the round bottle has peripheral grooves with a recessed cross-sectional shape, the peripheral grooves being formed by bending the wall of the barrel. The barrel can be vertically extended or contracted by the elastic deformation of the cross-sectional shape of each of the peripheral grooves. This makes it possible to cope with an increase in pressure in the bottle and a decrease in pressure in it. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a synthetic resin casing used for applications requiring a heat treatment step at a high temperature such as sterilization.

  Conventionally, as a filling method of synthetic resin casings such as polyethylene terephthalate (hereinafter referred to as PET) resin casings of content liquids such as fruit juices and teas that require sterilization, it is called a so-called high temperature filling method. There is a method, in which the casing is filled with the content liquid at a temperature of about 90 ° C., sealed with a cap, and then cooled, and the casing is considerably decompressed.

  For this reason, for applications involving high-temperature filling as described above, a so-called reduced pressure absorption panel, which is a region that can be easily deformed by depression, is formed in the body part, and this reduced pressure absorption panel is used during pressure reduction. By deforming into a depressed shape, it maintains a good appearance and secures rigidity as a casing in parts other than the vacuum absorption panel, so there are no troubles in the transport line of the chassis, stacked storage, vending machines, etc. I am doing so.

For example, Patent Document 1 describes a casing having a vacuum absorbing panel. FIG. 3 shows a casing shown in the embodiment of Patent Document 1. This casing 101 is a round PET resin casing having a capacity of 500 ml, and includes a mouth tube portion 102, a shoulder portion 103, and a trunk portion. An annular groove 106 is formed at a substantially central height position of the housing 1, and six vacuum absorbing panels 107 are formed below the annular groove 106. The reduced pressure absorption panel 107 has a substantially flat plate shape, and when the inside of the housing 1 is in a decompressed state, it can be easily deformed in a concave shape inside, so that the housing is deformed into an irregular shape in appearance. Thus, a function of absorbing (relaxing) the reduced pressure state (hereinafter referred to as a reduced pressure absorption function) can be exhibited without giving the feeling of being, that is, not conspicuous. Further, the rigidity as the housing is mainly borne by the column portion 109 formed between the adjacent vacuum absorbing panels 107.
Japanese Patent Laid-Open No. 10-58527

  In recent years, synthetic resin casings such as the PET resin casings have been used for foods that require retort treatment. In this case, the retort treatment is carried out by using pressurized heated water or steam in the retort kettle while filling the casing with food at a temperature of about room temperature to 80 ° C and sealing the mouth tube with a cap. Heat sterilization is performed at a temperature of about 130 ° C. for a time of about 20 minutes.

  As described above, when a synthetic resin casing is used for retort food, the casing is sealed with a cap and then sterilized at a temperature of about 120 to 130 ° C. in the retort pot. In addition, the pressure in the casing (internal pressure) increases due to the expansion of the contents, and a pressurized state is reached. Here, when using pressurized heated water, the bulging deformation of the housing can be suppressed by adjusting the pressure of the hot water to balance with the internal pressure, but when using heated steam Needs to be heat-treated near the saturated water vapor pressure at that temperature, and cannot be balanced with the internal pressure of the housing.

  For this reason, especially when heated steam is used, the body portion which is thin during retort processing is in a bulging deformation state. At this time, since the processing temperature is higher than the glass transition temperature in a general-purpose resin such as PET, the function of absorbing this pressurized state without causing local deformation (hereinafter referred to as a pressure absorbing function) is sufficient. Otherwise, permanent deformation will occur, and even if the inside of the housing is returned to normal pressure, it will not return to its original shape, resulting in a housing product having an irregular appearance.

  Furthermore, when the product is returned to room temperature after finishing the retort process, the internal pressure is reduced. In particular, when the contents are filled at a high temperature of about 70 to 80 ° C., the pressure is reduced at room temperature. It is necessary to make it the structure which also had. In other words, while ensuring a good appearance, the absorption function corresponding to the pressurized state and the decompressed state can be fully exhibited, and the deformation can occur smoothly in response to a large pressure fluctuation leading to the pressurized state and the decompressed state. Structure is required.

  Therefore, the present invention has been devised to solve the above-described problems, and both the pressure absorption function and the pressure reduction absorption function are fully exhibited, corresponding to the significant pressure fluctuations to the pressure state and the pressure reduction state. The object is to create a body wall structure that can be smoothly deformed, and an object of the present invention is to provide a synthetic resin casing that can be used satisfactorily for applications requiring a high-temperature heat treatment process, particularly for retort foods.

The means of the invention according to claim 1 for solving the technical problem is as follows:
Providing a circumferential groove having a concave cross-sectional shape formed by bending a wall of the trunk in the trunk of the round casing;
A configuration in which the body portion can be expanded and contracted in the vertical direction by elastic deformation of the cross-sectional shape of the circumferential groove, and it is possible to cope with both a pressurized state and a decompressed state inside the housing,
It is in.

  According to the above configuration of the first aspect, first, for the pressurized state inside the casing, the casing is basically inside the casing by using a round casing that has been conventionally used for carbonated drinks and the like. In addition to having high pressure resistance in the pressurized state, by providing a peripheral groove, the peripheral rib-like reinforcement function of the peripheral groove makes it possible to apply heat in a temperature range exceeding the glass transition temperature of the synthetic resin forming the casing. Even in the pressure state, remarkable or local bulging deformation of the body can be suppressed.

  Here, when there is no circumferential groove, the body part of the casing is formed thin, so even if it is a crystalline synthetic resin, due to the pressure state in the temperature range exceeding the glass transition temperature, Due to the circumferential extension of the wall, the bulging deformation is quite large and significant. In addition, if there is a part that is thin, deformation occurs in a concentrated state, causing permanent deformation beyond the elastic deformation region, and even if it is returned to normal pressure after heat treatment, the deformation state is partially It remains without being recovered. In order to eliminate such remarkable deformation or concentration of deformation in the thin wall portion, the wall thickness of the body portion must be considerably increased. However, in terms of material cost or the productivity of the housing Therefore, there is a limit to thickening.

  Further, according to the configuration of the present invention, the concave cross-sectional shape of the circumferential groove formed by bending the wall of the body portion is elastically deformed so as to widen the groove width depending on the pressurized state, and the body portion is It will be in the state extended in the up-and-down direction, and as a result, the internal volume of a housing will increase and a pressure absorption function will be exhibited.

  In addition, the deformation of the concave cross-sectional shape of the circumferential groove can be achieved without particularly extending and deforming the synthetic resin itself that forms the wall of the trunk portion in the axial direction of the housing, so that permanent deformation can be suppressed. It becomes. Further, according to the structure of the present claim, since there is no remarkable bulging deformation, it is possible to eliminate the remarkable deformation of the external appearance of the housing even during high temperature processing such as retort processing. And after a process, the deformation | transformation of the cross-sectional shape of a surrounding groove returns to an original shape elastically by the fall of temperature.

  That is, the structure of claim 1 suppresses the extension deformation in the circumferential direction of the wall of the trunk portion by the circumferential rib-like reinforcement function, and on the other hand, the trunk portion by the action of the concave cross-sectional shape of the circumferential groove. This is the function of this circumferential groove, especially under high temperatures and pressures such as retorting without significantly increasing the wall thickness of the torso. It became possible to provide a housing that can be processed.

  Next, when the treatment at a high temperature such as retort treatment is finished and the product is returned to room temperature, the internal pressure is reduced. In particular, when the contents are filled at a high temperature of about 70 to 80 ° C., the room temperature is reduced. However, in this case as well, due to the effect of the circumferential groove, it is possible to prevent a remarkable or local depression deformation of the wall of the trunk portion and to exhibit a reduced pressure absorption function.

  In other words, a round housing without a circumferential groove causes a wall of the trunk to be significantly or partially depressed in a decompressed state. It is possible to prevent a remarkable or local depression deformation of the wall. In the reduced pressure state, the concave cross-sectional shape of the circumferential groove formed by bending the body wall is elastically deformed so as to narrow the groove width, and the body part is contracted in the vertical direction. The internal volume of the body is reduced, the reduced pressure state inside the housing can be relaxed, and the reduced pressure absorption function can be exhibited by a method that is not conspicuous in appearance.

  As described above, according to the configuration of claim 1, the body portion is provided with a circumferential groove having a concave cross-sectional shape formed by bending a wall, and the body portion is formed by elastic deformation of the cross-sectional shape of the circumferential groove. By adopting a structure that can expand and contract in the vertical direction, both the circumferential rib-like reinforcement function and the pressure fluctuation (pressurization and depressurization) absorption function are exhibited, and the depressurization is performed at high temperature and at room temperature. Even in the state, it has become possible to provide a housing in which the shape of the body does not greatly deform or does not have local deformation.

  In addition, the cross-sectional shape of the circumferential groove formed in a concave shape, or the number of attached circumferential grooves, the attached position, etc. are the rigidity of the wall surface of the trunk part, the heat treatment temperature, etc., depending on the size of the casing, the wall thickness of the trunk part This is a design item that can be determined while conducting preliminary tests in consideration of the appearance and the like.

  The means of the invention described in claim 2 is that, in the invention described in claim 1, the average thickness of the housing body is in the range of 0.5 to 0.65 mm.

  According to the above configuration of claim 2, pressurization at a high temperature in combination with the reinforcing function by the circumferential groove by increasing the surface rigidity of the body wall by setting the average thickness of the body body to 0.5 mm or more. It is possible to more effectively prevent remarkable or local deformation of the wall of the body portion in a reduced pressure state at room temperature or the like. On the other hand, the wall thickness is naturally limited from the viewpoint of productivity reduction, material cost increase, and the like, and it is preferable to set the thickness within a range of 0.65 mm or less.

  According to a third aspect of the present invention, in the invention according to the first or second aspect, the groove depth of the circumferential groove is 1.5 mm or more, and the inclination angle of the groove side wall from the horizontal direction is 45 ° or less, It is in.

  The groove depth is 1.5 mm or more, and the inclination angle from the horizontal direction of the groove side wall is 45 ° or less. The cross-sectional shape of the circumferential groove can be smoothly deformed, and more sufficient pressurization and reduced pressure absorption functions are exhibited. The inclination angle is 0 ° or more.

  According to a fourth aspect of the present invention, there is provided the invention according to the first, second or third aspect, wherein w / W which is a ratio of the groove top width and the groove bottom width is 0.5 or less.

  When w / W is large and is close to 1, deformation near the bottom wall of the circumferential groove is facilitated, and the rib-like reinforcing function by the circumferential groove is reduced, so w / W is preferably 0.5 or less. .

  According to a fifth aspect of the present invention, in the first, second, third, or fourth aspect of the invention, at least two circumferential grooves are provided.

  According to the above-described configuration of the present invention, the two concave grooves are attached to the body portion at an appropriate interval, so that the deformation span of the body wall is shortened and the body portion is significantly expanded in a pressurized state at a high temperature. Outbreak deformation can be more effectively suppressed, and depression deformation in a reduced pressure state can be prevented.

  According to a sixth aspect of the present invention, in the invention according to the first, second, third, fourth, or fifth aspect, at least one circumferential groove is provided at each of an upper end portion, a substantially central height position, and a lower end portion of the trunk portion. There are three in total.

  According to the above-described configuration of the present invention, the barrel portion is sufficiently rigid by providing three concave grooves at substantially equal intervals, and the barrel portion is significantly bulged and deformed in a pressurized state at a high temperature. In addition to being able to prevent the depression deformation in the state more reliably, it is possible to extend the body portion in the vertical direction with the three circumferential grooves, and to exert a sufficient pressure and vacuum absorption function.

  According to a seventh aspect of the present invention, in the first, second, third, fourth, fifth or sixth aspect of the invention, the casing is used for retorting with heated steam.

  In the retort process, the sterilization process is performed at a high temperature of 120 to 130 ° C. According to the above-described configuration, particularly when heated steam is used, the thin barrel portion is bulged by adjusting the external pressure. Although it is difficult to suppress deformation, the pressure absorption function can be fully achieved by appropriately determining the cross-sectional shape, number of attachments, and position of the circumferential groove in response to such a high pressure state. In addition, it is possible to provide a housing that can be sufficiently used even in applications in which retorting is performed using hot steam.

  According to an eighth aspect of the present invention, there is provided the invention according to the first, second, third, fourth, fifth, sixth or seventh aspect, wherein the biaxially stretched blow-molded product made of a PET resin is used.

  According to the above-described configuration of claim 8, the biaxial stretch blow-molded casing made of PET resin can have heat resistance corresponding to the retort processing temperature, so that the circumferential groove of the present invention is used as the body portion. It can be used for a wide range of applications that require handling at high temperatures such as retort processing.

  As the polyethylene terephthalate resin used in the present invention, PET is mainly used. However, unless the essence of the PET resin is impaired, a copolymer polyester mainly containing ethylene terephthalate units and containing other polyester units is also used. In addition, for example, in order to improve heat resistance, a resin such as nylon resin or polyethylene naphthalate resin can be blended and used. Examples of the component for forming the copolyester include dicarboxylic acid components such as isophthalic acid, naphthalene 2,6 dicarboxylic acid, and adipic acid, propylene glycol, 1,4 butanediol, tetramethylene glycol, neopentyl glycol, cyclohexanedimethanol, Mention may be made of glycol components such as diethylene glycol.

  Furthermore, as long as the essence as a PET resin casing is not impaired, the PET resin casing of the present invention is, for example, PET resin / nylon resin / PET resin for improving heat resistance and gas barrier properties. It may have an intermediate layer such as nylon resin.

The present invention has the above-described configuration, and has the following effects.
In the invention according to claim 1, the body portion of the body portion can be obtained even in a pressurized state at a high temperature and a reduced pressure state at room temperature or the like by both functions of a circumferential rib-like reinforcing function and a pressure fluctuation absorbing function. It is possible to provide a housing that does not greatly deform in shape or that is not locally deformed.

  In the invention according to claim 2, by increasing the surface rigidity of the body wall by setting the average thickness of the body body to 0.5 mm or more, it can be combined with the reinforcing function by the circumferential groove at a high temperature. Remarkable or local deformation of the body wall in a pressurized state or a reduced pressure state at room temperature or the like can be more effectively prevented. On the other hand, when the average wall thickness is 0.65 mm or less, it is possible to prevent a significant decrease in productivity and a significant increase in material cost.

  In the invention described in claim 3, the groove depth is set to 1.5 mm or more, and the configuration related to the cross-sectional shape of the circumferential groove in which the inclination angle of the groove side wall from the horizontal direction is set to 45 ° or less, The cross-sectional shape of the circumferential groove can be smoothly deformed by the pressure and the reduced pressure, and more sufficient pressurization and reduced pressure absorption functions are exhibited.

  In the invention according to claim 4, w / W which is a ratio of the groove top width to the groove bottom width is set to 0.5 or less so that the rib-like reinforcing function by the circumferential groove is exhibited without impairing. Can do.

  In the invention according to claim 5, by attaching two circumferential grooves to the body portion at an appropriate interval, the deformation span of the body wall is shortened, and the body portion in a pressurized state at a high temperature is remarkable. Bulge deformation can be suppressed, and depression deformation in a reduced pressure state can be prevented.

  In the invention according to claim 6, by providing the three concave grooves at substantially equal intervals, the bulging deformation of the body portion in a pressurized state at a high temperature and the deformation in a reduced pressure state are more reliably ensured. In addition, the body portion can be extended in the vertical direction with the three circumferential grooves, and a sufficient pressure and vacuum absorption function can be exhibited.

  In the invention according to claim 7, it is possible to provide a casing that can sufficiently exert a pressure absorption function by the circumferential groove and can be sufficiently used even in an application of retorting using thermal steam. it can.

  In the invention of claim 8, the biaxially stretched blow-molded casing made of PET resin can be widely used for applications that require handling at a high temperature such as retort treatment.

Embodiments of the present invention will be described below with reference to the drawings.
1 and 2 show an embodiment of the synthetic resin casing of the present invention. FIG. 1 is a half longitudinal front view of the housing 1. This housing 1 is a biaxially stretched blow molded product made of PET resin, and has a mouth tube portion 2, a shoulder portion 3, a trunk portion 4, and a bottom portion 5. The trunk portion 4 has a diameter of 63 mm, an overall height of 130 mm, and is used for 300 ml. It is a small round bottle. The mouth tube portion 2 is whitened by the thermal crystallization process, and the bottom portion 5 is formed in a depressed shape.

  Further, the average thickness of the body portion is 0.58 mm, and the body portion 4 has a concave cross-sectional shape by bending the wall 4a in the vicinity of the upper end, in the vicinity of the lower end, and at the center height position. Are provided at equal intervals. Further, the groove depth D of the circumferential groove 6 is 5 mm, the groove upper end width W is 5 mm, the groove bottom width w is 1.75 mm (w / W = 0.35), and the groove side wall is 63 mm with respect to the diameter of the body 4. The inclination angle A from the horizontal direction of 6b is 20 ° (see FIG. 2 (outer contour diagram in the enlarged vertical section of the main part in the vicinity of the circumferential groove 6 located at the central height position of the casing 1 of this embodiment). ). In the present embodiment, a relatively small (300 ml) housing in which the influence of the pressurized state or the reduced pressure state due to temperature change appears severely was used.

Example The casing 1 molded as described above was filled with 80 ° C. water, capped and subjected to a retort treatment by a steam heating method at 124 ° C. for 20 minutes, and then allowed to cool to room temperature. The test was carried out and the shape change of the housing 1 was observed. Immediately after the retorting process, the wall surface between the circumferential grooves 6 of the trunk portion 4 was slightly bulged, but there was no noticeable or local bulging deformation. Moreover, in the state returned to room temperature, although the wall surface between the circumferential grooves 6 of the trunk | drum 4 will be in a slightly depressed state, the remarkable depression-like deformation | transformation in the trunk | drum 4 was not observed.

  Then, in a pressurized state at a high temperature, the concave cross-sectional shape of the circumferential groove 6 is deformed so that the groove upper end width W is opened by about 1 mm from 5 mm to 6 mm. As a result, the body part 4 extends in the vertical direction. Thus, the internal volume of the housing 1 is increased and the pressure absorption function is exhibited.

  On the other hand, since it is sealed with a cap immediately after filling with water at 80 ° C., the housing 1 is in a reduced pressure state when it is returned to room temperature, but the concave cross-sectional shape of each circumferential groove 6 is the groove upper end width. W was deformed so as to be reduced by approximately 0.3 mm from 5 mm to 4.7 mm. As a result, the body part 4 contracted in the vertical direction, the internal volume of the housing was reduced, and the reduced pressure absorption function was exhibited.

  As described above, in the casing 1 of the present embodiment, the three circumferential grooves 6 are provided at equal intervals in the vicinity of the upper end, the central height position, and the lower end of the trunk portion 4, thereby Combined with the circumferential rib-like reinforcement of the groove 6 and the pressure and vacuum absorption function, it was possible to provide a casing 1 that is not noticeable or has no local deformation even under severe conditions of retort processing. .

  The number of peripheral grooves 6 to be attached, the position of the peripheral grooves 6, the cross-sectional shape of the peripheral grooves 6, etc. can be determined while conducting preliminary tests in consideration of the size of the casing 1, conditions such as heat treatment temperature, appearance, etc. It is. Moreover, the cross-sectional shape etc. of the circumferential groove 6 can be made into the shape which is easy to expand-contract vertically by setting the groove depth D, the inclination angle of the groove side wall 6b, etc.

  In addition, this invention is not limited to a present Example about the shape of a housing, and the kind of synthetic resin is not limited to PET resin. Moreover, it is not limited to the housing for retort processing.

  The synthetic resin casing of the present invention can be used for severe applications such as steam heating type retort treatment, and can be expected to be used in a wider range of applications.

It is a half vertical front view which shows one Example of the housing of this invention. It is an outer outline figure of the principal part expansion longitudinal section of the peripheral groove vicinity of the housing of FIG. It is a whole front view which shows the prior art example of a housing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1; Housing 2; Mouth part 3; Shoulder part 4; Trunk part 4a; Wall 5; Bottom part 6; Circumferential groove 6a; Groove upper end 6b: Groove side wall 6c; Groove width A; inclination angle 101; housing 102; mouth tube portion 103; shoulder portion 104; trunk portion 105; bottom portion 106; annular groove portion 107;

Claims (8)

A circumferential groove (6) having a concave cross-sectional shape formed by bending a wall (4a) of the body (4) is provided in the body (4) of the round casing (1), and the circumferential groove (6 ) In which the body (4) can be expanded and contracted in an up-and-down direction by elastic deformation of the cross-sectional shape of the casing (1), and can be adapted to both the pressurized state and the decompressed state inside the housing (1). Steel body. The synthetic resin casing according to claim 1, wherein the average thickness of the casing (1) body (4) is in the range of 0.5 to 0.65 mm. The synthetic resin according to claim 1 or 2, wherein the groove depth (D) of the circumferential groove (6) is 1.5 mm or more and the inclination angle (A) of the groove side wall (6b) from the horizontal direction is 45 ° or less. Body. The synthetic resin casing according to claim 1, 2 or 3, wherein w / W which is a ratio of the groove upper end width (W) to the groove bottom width (w) is 0.5 or less. 5. The synthetic resin casing according to claim 1, wherein at least two circumferential grooves are provided. A total of three circumferential grooves (6), one each for the upper end of the body (4), the substantially central height position, and the lower end, are provided. 5. A synthetic resin casing as set forth in 5. The synthetic resin casing according to claim 1, wherein the synthetic resin casing is used for a retort treatment with heated steam. 8. The synthetic resin casing according to claim 1, wherein the synthetic resin casing is a biaxially stretched blow-molded product made of polyethylene terephthalate resin.

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