JP2001031151A - Heat insulation container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance heat resistance and prevent thermal deformation of an interior body and an exterior body by interposing a foamed molding having a specified thermal shrink property which is foam-molded in a form from thermoplastic polyester resin foaming particles as a heat insulation layer, at least between the interior body and the exterior body of a container body of a container. SOLUTION: An interior body 11 and an exterior body 12 are separately formed and the mutual ends of both bodies 11, 12 are connected by welding or the like to constitute the heat insulation container in a state that a heat insulation layer 13 is interposed between both bodies when producing a container body 1 of the heat insulation container A. Thermoplastic polyester resin foaming particles are foam-molded in a form as the heat insulation layer 13 used in this case. The heat shrink of the foamed molding is 1 mm or less per 100 mm under a condition of 24 hours, 120 deg.C. The crystallization and fusion ratio of the synthetic resin foam forming the heat insulation layer 13 are preferably 20-40%, and 40% or higher respectively. Further, it is preferable that a similar heat insulation layer 23 is interposed between the interior body 21 and the exterior body 22 in the lid body 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat insulating container, and more particularly, to a heat insulating container in which a heat insulating layer is interposed between an inner body and an outer body made of a synthetic resin.

[0002]

2. Description of the Related Art Conventionally, in an insulated container (container) for transporting foodstuffs and the like, an inner body and an outer body made of a non-foamed synthetic resin are used in order to maintain the heat and cold state well. Between them, a structure in which a core material made of a foamed resin is interposed as a heat insulating layer is employed. The above-mentioned insulated containers are often washed and disinfected with hot water frequently for hygienic needs.

[0003] Therefore, in order to prevent water from entering between the inner body and the outer body, the joint between the inner body and the outer body is bundled by welding with a thermoplastic resin to improve the integrity, for example. The invention described in Japanese Patent Publication No. 59-11098 has been proposed. As a method of assembling such a heat insulating container, after putting a heat insulating core material inside the exterior body,
Further, a method is adopted in which an interior body is incorporated inside and the joint between the interior body and the exterior body is welded with a thermoplastic resin.

[0004] This joining is performed under reduced pressure. However, it is inevitable that air remains between the exterior body and the interior body which are to be a heat insulating layer, and the load is burdened by the subsequent gas permeation and multi-stage stacking when the container is used. When hot rice etc. is stored inside the container due to the deformation caused by heat, the synthetic resin of the interior body is slightly softened by heat, and the interior body expands inward due to the expansion of the residual air and deforms. There is.

In response to this, Japanese Unexamined Utility Model Publication No. Hei 3-43480 discloses that an engaging portion is partially provided at a position corresponding to the outer peripheral surface of the inner body and the inner peripheral surface of the outer body to prevent deformation of the peripheral surface. Prevented insulated containers have been proposed. In addition, there are foamed resin and rigid urethane foam as a material to be attached to and injected into the heat insulating layer.

When a foamed resin is exposed to a high temperature exceeding 80 ° C., the resin itself is softened and changes such as expansion or contraction occur. Further, the same phenomenon occurs in the same urethane foam in the same urethane foam. The heat-resistant temperature of the synthetic resin used for the inner body and the outer body is generally 120 ° C., but as a heat-insulating container, the heat-resistant temperature of the heat-insulating material is 75 ° C. to 80 ° C. It has heat resistance performance as a container.

[0007] Insulated containers are mainly used in rice cookers and school lunch departments, and as ancillary equipment, sterilizers and sterilizers are used. These are usually used at about 120 ° C or higher after washing dishes other than the insulated containers. Heat treatment is carried out in a sterilizer and sterilizer for 10 hours. In recent years, this is a measure against the occurrence of food poisoning caused by O-157 and other botulinum bacteria.

[0008] From the viewpoint of hygiene management, it is desired to perform heat sterilization treatment on an insulated container, but at present, it cannot be performed because the heat resistance is not sufficient as described above.

[0009]

In order to prevent the deformation of the peripheral surface as described above, it is difficult to partially provide the engaging portions at the corresponding positions on the outer peripheral surface of the inner body and the inner peripheral surface of the outer body. Although this is one of the effective countermeasures, there is a limit to the heat resistance of the heat insulating material, and heat sterilization at 120 ° C. cannot be performed. This is because, when the heat sterilization treatment is performed at such a high temperature, the container may be deformed, or the heat insulating material may be deformed by heat, thereby impairing the heat insulating function.

[0010] Further, in the heat insulating container, the joint between the inner body and the outer body is closed by welding with a thermoplastic resin for the purpose of preventing infiltration of washing water into the heat insulating material and strengthening the sense of unity. There is a problem that the remaining air or the like expands under high-temperature conditions and causes deformation of the container. The inventor of the present invention has made intensive studies to provide a heat insulating container capable of sufficiently preventing the deformation of the peripheral surface, and has completed the present invention.

[0011]

SUMMARY OF THE INVENTION The present invention is to provide an insulated container capable of solving the above-mentioned problems, and as the insulated container, at least the interior of the container body among the containers as described in claim 1 Between the body and the exterior body, a foamed molded body having a heat shrinkage of not more than 1 mm per 100 mm at 120 ° C. for 24 hours is formed by in-mold foaming of thermoplastic polyester resin foam particles as a heat insulating layer. It is characterized by being done.

In the heat insulating container according to the first aspect of the present invention, the heat-shrinkage of the foamed molded article as the heat-insulating layer is very excellent, such that the heat shrinkage at 120 ° C. for 24 hours is 1 mm or less per 100 mm. It is possible to sufficiently suppress the thermal influence on the inner body and the outer body made of a synthetic resin, and to prevent the inner body and the outer body from being thermally deformed. Next, according to the present invention, as described in claim 2, thermoplastic polyester-based resin foam particles are formed in a mold as a heat insulating layer between an inner body and an outer body made of a synthetic resin of at least the container body in the container. A foamed molded product having a crystallinity of 20 to 40% and a fusion rate of 40% or more is interposed.

According to the second aspect of the present invention, the foamed molding to be the heat insulating layer has a crystallinity of 20 to 40% and a fusion ratio of 40%.
As described above, they exhibit extremely high heat resistance, and can sufficiently suppress the thermal influence on the interior body and the exterior body, and can surely prevent the thermal deformation thereof. As described in the invention of claim 3, the thermoplastic polyester-based resin has at least one selected from the group consisting of isophthalic acid and cyclohexanedimethanol in all of its components.
When the total amount of the seed components is in the range of 0.5 to 10% by weight, the heat insulating layer of the heat insulating container has a good crystallinity and a fusion rate, and the heat insulating container has a shrinkage. It is possible to provide a product having less dimensional stability and having less dimensional stability.

According to the present invention, there is provided a vent valve which enables a one-way air flow when a pressure difference is generated between a container wall and an external part of an exterior body. Is provided. When the vent valve is provided as in the fourth aspect of the present invention, when the outside air pressure becomes higher than the inside of the container wall, the vent valve is opened, air flows into the container wall from the outside, and the outside and the container wall are opened. Therefore, no deformation occurs when the pressure is returned to normal pressure after vacuum cooling. In addition, since the vent valve opens and allows air to flow in one direction due to a pressure difference between the inside and outside of the container wall as described above, even when the container is washed with water,
As long as no pressure is applied, there is no risk of water entering from the vent valve portion.

According to the present invention, a rib for preventing deformation of the interior body is provided on the outer wall surface of the interior body. By providing a rib for preventing the deformation of the inner body as in the invention of claim 4, it is possible to provide an insulated container in which the inner body is unlikely to be deformed. It can be reliably prevented from bulging inward and deforming.

Further, according to the present invention, as set forth in claim 6, the outer peripheral surface of the interior body and the inner peripheral surface of the exterior body are partially connected and fixed. When the inner body and the outer body are partially fixed and fixed as in the invention of claim 6, the deformation of the inner body and the outer body due to the load burden due to the multi-tiered stacking during use causes mutual engagement. It can be prevented by the deformation prevention part due to the engagement of the part, and when the warm rice etc. is put inside the container, the resin itself expands and the circumference of the inner body caused by the expansion of the air remaining between the inner body and the outer body As a result, surface expansion can be prevented, and a durable container having extremely high shape stability can be provided.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of an insulated container A according to an embodiment of the present invention, in which a part of the container is in an open state, in which 1 is a container main body and 2 is a lid. The container body 1 shown in the figure has an inner body 11 and an outer body 12 separately formed, and a heat insulating layer 13 made of a synthetic resin foam is interposed therebetween. The ends are joined by welding means or the like. As a specific means of the joining, each end of the inner body 11 and the outer body 12 are butted on the outer surface, a groove is formed in the abutting portion, and a welding rod of a thermoplastic resin is used along the groove. In this case, a method of airtightly joining and integrating them by welding is adopted. Reference numeral 14 indicates the joint.

The end portions of the inner body 11 and the outer body 12 can be joined to each other by other means such as bonding, but from the viewpoint of maintaining airtightness and joining strength, it is preferable to use welding means as described above. preferable. The heat-insulating layer 13 interposed between the inner body 11 and the outer body 12 is formed by foaming thermoplastic polyester resin foam particles in a mold for 24 hours, 12 hours.
A foam molded article having a heat shrinkage of 1 mm or less per 100 mm under the condition of 0 ° C. is interposed.

The heat-insulating layer 13 made of a foamed molded article is a foamed molded article obtained by subjecting foamed thermoplastic polyester resin particles to in-mold foaming and having a crystallinity of 20 to 40% and a fusion ratio of 40% or more. May be used. The lid 2 fitted to the container body 1 is made of synthetic resin foam as a heat insulating layer 23 between an interior body 21 and an exterior body 22 formed of foamed synthetic resin, similarly to the container body 1. It is configured with a body interposed. The lid 2 is also formed in the same manner as the container body 1, but in the case of this embodiment, the interior 21
The exterior body 22 and the exterior body 22 are integrally formed into a hollow shape by hollow formation, and the heat insulation layer 23 made of a foam is interposed by injecting and foaming and filling urethane and the like into the hollow. Reference numeral 24 indicates a mouth closed after injection foaming.

When a pressure difference is generated between the inside and the outside of the container wall in a part of the exterior body 12, the valve is opened by the pressure difference to provide a check valve that allows only one-way air flow. It is preferable to provide a ventilation valve A1. The ventilation valve A1 includes an annular mounting base member 50 having a circular opening 51 in the center as shown in FIG. 2, and a valve holding member 60 for holding a valve member 30 and a valve holding member 40 described below inside, It is configured as follows.

The mounting base member 50 is made of synthetic resin and has a cylindrical portion 52 protruding to the back side at the periphery of the opening 51. A screw 53 is formed on the inner periphery so as to leave the end of the cylindrical portion 52. An annular concave groove 55 is formed on the surface of the outer peripheral plate portion 54 of the mounting base member 50, and an O-ring 56 is fitted in the concave groove, and a valve holding member assembled to the mounting base member 50. By contacting the peripheral portions of 60, a space between them is maintained in a sealed state.

An annular welding ridge 57 is formed on the back surface of the outer peripheral plate portion 54, and the cylindrical portion 52 is fitted into a mounting hole of the outer casing 12 of the heat insulating container A to be used. In this state, the protruding edge 57 is pressed against the exterior body 12 and rotated at a high speed, so that the portion of the protruding edge 57 can be melted by frictional heat and welded to the exterior body 12. At this time, if the outer diameter of the outer peripheral plate portion 54 has a rectangular shape such as a hexagon, rotation can be given by using rotation applying means such as a nut runner. In addition, the said protruding edge 5
7, the mounting base member 50 can be fixed to the exterior body 12 by an adhesive means or the like.

The valve holding member 60 includes a flange-shaped peripheral portion 61 facing the surface of the outer peripheral plate portion 54 of the mounting base member 50, and a cylindrical circular protruding portion 62 protruding from the peripheral portion 61 to the back side. The distal end side of the circular protruding portion 62 is formed as a cylindrical portion 62 a protruding from the inner central plate portion 64, and is inserted into the opening 51.
A screw 63 corresponding to the screw 53 on the inner periphery of the opening 51 is formed on the outer periphery of the base of the circular projection 62.
1 is provided so as to be freely screwed. Further, a vent hole 65 is formed in the central plate portion 64. The surface side of the circular protruding portion 62 from the central plate portion 64 is concavely formed in a polygonal shape such as a hexagon, and when screwing to the mounting base member 50, rotation is performed using the rectangular shape of the concave portion 66. It is formed so that it can be given.

A valve member 3 made of a soft elastic rubber-like sheet made of silicon or the like having a through hole 31 in the center is provided in the cylindrical portion 62a on the protruding end side of the circular protruding portion 62.
0 is fitted so as to face the central plate portion 64.
Further, a valve holding member 40 is removably fitted so as to hold the valve member 30 between the central plate portion 64 and the central plate portion 64 at a peripheral portion thereof. In the case of the drawing, a protruding edge 41 is formed on one side of the peripheral edge of the valve holding member 40, and the peripheral edge of the valve member 30 is sandwiched between the protruding edge 41 and the step 67 on the peripheral edge of the central plate portion 64. It has become.

In this embodiment, the valve holding member 40 has a through hole 3
1 is provided, and in the fitted state, the protrusion 42 elastically contacts the center of the valve member 30 so that the through hole 3 can be closed.
1 is held in a closed state, and the valve member 30 resists the elastic force only when the pressure of the valve holding member 40 having the protrusion 42 becomes higher than the surface side (outside) of the check valve. By separating from the protrusion 42, the through-hole 31 is opened, and air flows from the valve holding member 40 side to the surface side. Reference numeral 43 denotes a ventilation hole provided in the periphery of the projection 42 of the valve holding member 40 and the like.

Therefore, the check valve A of the first embodiment
1 is used to form a ventilation hole that allows only the flow from the inside of the container wall to the outside in the heat insulating container A shown in FIG. FIG. 3 shows a ventilation valve A2 according to a second embodiment of the present invention. Further, in contrast to the previous vent valve A1, the vent valve A2 of the embodiment that allows only air flow from outside to the inside of the container wall differs from the valve retainer 40 of the first embodiment in that the valve retainer is different from the valve retainer 40 of the first embodiment. The member 40 is not provided with a projection for closing the through hole 31 of the valve member 30 and has a vent hole 4 in the center.
3a is provided. Description will be made sequentially with reference to FIG.
A substantially hemispherical projection 69 capable of closing the through hole 31 of the valve member 30 is provided at a central portion of the central plate portion 64 opposed to the valve holding member 40 with the valve member 30 as an intermediate portion. In this state, the protrusion 69 elastically contacts the valve member 30 to hold the through hole 31 in a closed state, and a vent hole 65a is provided in a peripheral portion thereof. Only when the pressure of the side of the central plate portion 64 having the protrusion 69 becomes higher than that of the valve holding member 40, the valve member 30 separates from the protrusion 69 against the elastic force, and the through hole 31 is formed. Is opened to open the valve, and air flows from the front side (outside) to the valve holding member 40 side.

Therefore, the ventilation valve A of the second embodiment
Reference numeral 2 is used to form a ventilation hole in the heat-insulating container A shown in FIG. FIG. 4 shows an inner body 1 of the container body 1.
FIG. 2 is a perspective view showing an outer wall surface of No. 1; As shown in this figure, the outer wall surface of the interior body 11, that is, the bottom surface 1 on the side in contact with the heat insulating layer 13
Ribs 111 for preventing deformation of the interior body 11 are provided on the side surface 1a and the side surface (outer peripheral surface) 11b.

As the rib 111 for preventing this deformation,
On the bottom surface 11a of the inner body 11, a circular rib 111a is disposed substantially at the center, and a plurality of substantially linear ribs 111b are formed in a shape starting from the circle and extending radially around the circumference.
Is provided. On the side surface 11b, the bottom surface 1
A plurality of linear ribs 111c extending from the linear rib 111b of 1a are provided in a direction perpendicular to the bottom surface 11a. A part of the plurality of linear ribs 111b is bent shortly before reaching the side surface 11b such that the mutually continuous ribs 111b and 111c form a right angle at the boundary between the bottom surface 11a and the side surface 11b. I have.

In the present invention, the shape of the rib provided to prevent deformation of the interior body 11 is not limited to the above-described embodiment, and may be any shape as long as the object can be achieved. . Further, in the present invention, a case where the outer peripheral surface of the inner body and the inner peripheral surface of the outer body are partially connected and fixed will be described with reference to FIG.
Numeral 72 denotes an engaging portion protruding from the opposed outer peripheral surfaces 73, 73 of the inner body 11, and has a substantially rectangular projection shape in the figure that can be engaged in the outer peripheral surface height direction. 82, 82 are the exterior body 1
Two engaging portions protruding from the inner peripheral surfaces 83 facing each other, and have a groove angle shape that can correspond to the engaging portions 72 on the interior body 11 side.

The engaging portions 72, 72 and 82, 82 can be engaged with each other by combining the inner body 11 with the outer body 12, and are configured as deformation preventing portions on the respective peripheral surfaces. ing. Since the engagement between the engaging portions is performed at the portion of the deformation preventing portion, the heat insulating layer 1
3 is formed without interposition.

In practice, the deformation preventing portion can be arbitrarily formed at a required position other than that shown. Depending on the area and shape of the peripheral surface of the container, the container may be formed at a position where the peripheral surface expansion must be prevented. However, it is preferable that the heat insulating layer 13 between the inner body 11 and the outer body 12 is not lost so much. As another connecting means, as shown in FIG. 6, a screw 90 is used to fasten a screw 90 from the outside of the exterior body 12 to the screw fixing hole 94 of the interior body 11 from the mounting hole 92 through the through hole 93 of the heat insulating layer 13. In particular, if the screw 90 is a self-drilling screw, the screw can be screwed into the screw fixing hole 94 while tapping, which is convenient. Reference numeral 95 denotes a closing cap.

Hereinafter, the thermoplastic polyester resin serving as the heat insulating layer in the heat insulating container of the present invention will be described in detail. <Thermoplastic polyester-based resin> As the thermoplastic polyester-based resin forming the foamed molded article to be the heat insulating layer in the present invention, for example, polyethylene terephthalate (PET) synthesized by a polycondensation reaction of terephthalic acid and ethylene glycol is used. ), Any of various conventionally known thermoplastic polyester-based resins can be used.

However, the conventional thermoplastic polyester resin such as the above PET generally has a high gas barrier property and requires a long time to impregnate the foaming agent. Therefore, the resin is impregnated with a foaming agent (impregnation step). Then, the pre-expanded particles are obtained by heating and pre-expanding the particles to obtain pre-expanded particles (pre-expansion step). The pre-expanded particles are filled in a mold, expanded by heating, and subjected to foam molding (in-mold expansion step). If a foam molded body, that is, a heat insulating layer in this case, is manufactured by a conventional foam molding method, time, cost, and labor may be required.

Further, in the above-mentioned conventional thermoplastic polyester resin, crystallization easily proceeds by heating, that is, since the crystallization speed is high, the crystallinity of the pre-expanded particles is excessively increased by the heating during the impregnation or the pre-expansion. Become higher,
There is also a problem that during the in-mold foam molding, the foaming fusion property between the foamed particles is reduced. For this reason, using a general-purpose foam molding machine, for example, a gauge pressure of steam of 0.5M
By foam molding under ordinary molding conditions such as Pa or less, although a foam molded article excellent in heat resistance can be obtained, the foamed particles are fused together with a high fusion rate, integrated, excellent in strength It is not possible to produce foamed moldings.

Therefore, in order to produce a foamed molded article having a high fusion rate by using a conventional thermoplastic polyester resin such as PET, a special function such as a large amount of steam can be uniformly supplied into a mold. It is necessary to carry out molding under special molding conditions such that the gauge pressure exceeds 0.5 MPa using a special foam molding machine provided with. However, due to such special molding conditions, the foam molded article produced has an excessively high degree of crystallinity, for example, exceeding 40%, and is excellent in heat resistance but brittle. On the contrary, the required strength cannot be obtained.

Further, a foam molded article having a crystallinity exceeding 40% has a problem that the dimensional stability particularly in a high-temperature environment is reduced, and the above-mentioned fracture due to heat shrinkage is likely to occur. Therefore, in the present invention, it is preferable to use, as the above-mentioned thermoplastic polyester resin, a resin whose crystallization speed is particularly suppressed.

That is, the thermoplastic polyester resin in which the rate of crystallization is suppressed is smaller than the conventional PET or the like.
Even if the pre-expanded particles are exposed to a high temperature due to heating, the crystallinity of the pre-expanded particles is prevented from becoming excessively high, and the foam fusion property during in-mold foam molding is prevented from being significantly reduced. Therefore, it has excellent foam fusion property during in-mold foam molding,
Easily produce foamed moldings with excellent mechanical strength and dimensional stability under ordinary molding conditions using a general-purpose foaming molding machine without using a special foaming molding machine. It becomes possible.

The crystallization rate of the thermoplastic polyester-based resin is determined by using a differential scanning calorimeter (DSC) according to the measurement method described in Japanese Industrial Standards JIS K7121. The temperature can be evaluated by the temperature at which crystallization occurs when the temperature is raised. That is, it can be said that the higher the crystallization peak temperature is, the more the resin requires a larger amount of heat to promote crystallization, that is, the lower the crystallization speed is.

Specifically, a predetermined amount of a thermoplastic polyester resin as a measurement sample is filled in a DSC measurement container, and while the temperature is raised at a rate of 10 ° C./min, the crystallization peak temperature is reduced. Measured. If the range of the crystallization peak temperature of the thermoplastic polyester resin measured in this way is about 130 ° C. or higher, the crystallization rate is suppressed as described above, and the thermoplastic polyester resin is a suitable thermoplastic polyester resin. It can be said that.

The crystallization peak temperature is preferably 180 ° C. or lower in the above range. When the crystallization peak temperature exceeds 180 ° C., the glass transition point of the resin becomes high, so that the condition width of the in-mold foaming becomes narrow, so that the molding becomes rather difficult. There is also a possibility that the shrinkage is likely to occur on the surface of the body, and a problem that a foam molded article having a good appearance cannot be obtained. In addition, a problem that the manufactured foam molded article becomes brittle may occur.

In consideration of the production of good pre-expanded particles and good foamed molded articles in consideration of the balance of the above-mentioned respective properties, the peak temperature of the thermoplastic polyester resin falls within the above range. 132-175 ° C
The temperature is preferably about 135 to 170 ° C. The thermoplastic polyester-based resin satisfying such characteristics is not limited to the above-mentioned ones. For example, at least one component selected from the group consisting of isophthalic acid and cyclohexanedimethanol in all components is 0% in total. Those contained in the range of 0.5 to 10% by weight.

That is, as a dicarboxylic acid, a compound represented by the formula (1):

[0043]

Embedded image

Either using isophthalic acid represented by the following formula, or using cyclohexane dimethanol as a diol, or using both of them together, and when using either one alone, the content ratio of the one alone is If both are used together, the total content of
The above-mentioned thermoplastic polyester-based resin in the range of 0.5 to 10% by weight in all components is crystallized by the action of isophthalic acid and / or cyclohexanedimethanol to suppress the crystallization of the resin. Since the peak temperature is in the range of 130 to 180 ° C., it is possible to manufacture a good foam molded article that does not cause the various problems described above.

The content of isophthalic acid and / or cyclohexanedimethanol is in the above range in consideration of the balance between the above properties and the production of good pre-expanded particles and good foamed molded articles. Especially, it is preferably about 0.6 to 9.5% by weight, more preferably about 0.7 to 9% by weight.
Among the above, as the cyclohexanedimethanol, basically, two methanol moieties are respectively substituted at the 1-position and 4-position of the cyclohexane ring, a formula (2):

[0046]

Embedded image

The 1,4-cyclohexanedimethanol represented by the formula (1) is used, but the isomer in which two methanol moieties are substituted at other positions of the cyclohexane ring can be used together in a small amount. Among the other components constituting the thermoplastic polyester resin together with isophthalic acid and cyclohexanedimethanol, examples of the dicarboxylic acid include terephthalic acid and phthalic acid.

Examples of the diol component include ethylene glycol, α-butylene glycol (1,2-butanediol), β-butylene glycol (1,3-butanediol) and tetramethylene glycol (1,4-butanediol).
Butanediol), 2,3-butylene glycol (2,
3-butanediol), neopentyl glycol and the like.

In addition to the above-mentioned components, the raw materials of the thermoplastic polyester-based resin include, for example, tricarboxylic acids such as tricarboxylic acids such as trimellitic acid and tetracarboxylic acids such as pyromellitic acid as acid components. Polyhydric carboxylic acids and their anhydrides, or alcohol components, such as triols such as glycerin, tetraols such as pentaerythritol, trihydric or higher polyhydric alcohols and the like, the crystallinity of the thermoplastic polyester resin and A small amount may be contained within a range that does not affect the crystallization speed and the like.

The above-mentioned thermoplastic polyester resin contains the above-mentioned components in a predetermined ratio, that is, as described above, isophthalic acid and / or cyclohexanedimethanol in a total amount of 0.5 to 10% by weight. It is produced by subjecting a raw material to a polycondensation reaction as in the conventional case. In addition, the thermoplastic polyester-based resin is obtained by mixing two or more kinds of thermoplastic polyester-based resins having different contents of isophthalic acid and / or cyclohexanedimethanol with respect to the content of isophthalic acid and / or cyclohexanedimethanol in all the components. Can be also produced by blending so that the total amount is in the range of 0.5 to 10% by weight, and melting and mixing under heating using, for example, an extruder.

According to this method, at the stage of producing the pre-expanded particles, the pre-expanded particles can be produced only by changing the mixing ratio of two or more kinds of thermoplastic polyester resins having different contents of isophthalic acid and / or cyclohexanedimethanol. The content ratio of both components in the pre-expanded particles can be adjusted. For this reason, there is an advantage that the adjustment operation can be simplified as compared with the case where the content ratio of both components is adjusted in the resin synthesis stage, and the specification can be flexibly changed.

Further, by using, for example, a material recovered and reclaimed from used PET bottles as one kind of thermoplastic polyester resin to be compounded, effective reuse of resources and reduction of trash can be achieved. Another advantage is that the cost of the pre-expanded particles can be reduced. In the above method, the two resins are melted and mixed sufficiently under heating so that each resin is alloyed by a transesterification reaction between two or more kinds of thermoplastic polyester resins to form a uniform thermoplastic polyester resin. Is preferred.

When the pre-expanded particles are mixed with a foaming agent under high-pressure melting using an extruder or the like as described later, pre-expanded, and then cut and produced, two kinds of pre-expanded particles are used as described above. Melting of the above resins, production of a uniform thermoplastic polyester-based resin by mixing, is performed in the above-described extruder prior to mixing of the foaming agent, and then it is efficient to carry out the above-described production method continuously. Is preferable.

However, a uniform thermoplastic polyester resin prepared by melting and mixing two or more resins in advance using another apparatus is charged into an extruder, and pre-foamed by the above-mentioned production method. Particles may be produced. The thermoplastic polyester resin used in the present invention is used for melting and mixing at the time of producing pre-expanded particles, and at the time of producing a foamed molded article by in-mold foam molding using the produced pre-expanded particles. Considering moldability, its intrinsic viscosity (measuring temperature: 35 ° C, solvent: orthochlorophenol)
Is preferably about 0.6 to 1.5. <Pre-expanded Particles> Pre-expanded particles may be produced by impregnating the above-mentioned thermoplastic polyester-based resin with a foaming agent and then heating and pre-expanding the particles as in the conventional case.

However, the step of impregnating the thermoplastic polyester resin with a foaming agent is omitted to save time, cost and labor, and the crystallinity of the pre-expanded particles to be produced is further reduced, so that the in-mold foam molding is performed. In order to further suppress the decrease in the foam fusion property at the time, as described above, the thermoplastic polyester resin is mixed with a foaming agent under high-pressure melting and prefoamed to obtain a prefoamed body. This is preferably cut to produce pre-expanded particles.

As a method for preliminarily foaming a thermoplastic polyester resin by mixing it with a foaming agent under high pressure melting, an extrusion foaming method using an extruder is efficient and preferably employed. The extruder that can be used is not particularly limited, and is a single-screw extruder, a twin-screw extruder, or the like usually used for this type of extrusion foam molding, and may be a tandem type in which these are connected. An extruder having excellent melting and mixing capabilities is preferred.

Various extruders can be used. For example, there are an annular base, a flat base, a nozzle base, and a multi-nozzle base in which a plurality of nozzles are arranged. These bases can be used to make pre-foams of various shapes, such as sheet, plate and rod. Various methods are used to make the prefoamed body have the above-mentioned predetermined shape.

For example, in order to obtain a sheet-shaped prefoamed body, a cylindrical prefoamed body extruded from an annular die is made into a sheet by advancing on a mandrel, or a sheet having a thickness extruded from a flat die. A plate-shaped prefoam may be formed into a sheet by a chill roll. Further, in order to obtain a thick plate-shaped prefoamed body, a method in which foaming is advanced while being in close contact with a pair of metal plates to obtain a predetermined thickness is employed.

As a method for cooling the pre-foamed body, in addition to air cooling or water cooling, the pre-foamed body is brought into contact with a temperature-controlled cooling device.
Various methods can be used. It is important that the prefoam be cooled as quickly as possible to prevent excessive crystallization. The pre-expanded particles of various shapes produced in this way are appropriately cut into a columnar shape, a square shape, a chip shape, or the like to complete the pre-expanded particles.

The cooling and cutting of the prefoamed body can be performed at an appropriate timing. For example, the prefoamed material extruded from the die is cooled by passing it through water at any time during foaming or after foaming is completed, and then the pelletizer is cooled.
It may be cut into a predetermined shape and size using a method such as the above. Alternatively, the prefoamed body immediately before or immediately after the completion of foaming, which has been extruded from the die, and immediately before cooling, may be immediately cooled and then cooled.

Further, the prefoamed material extruded in the form of a sheet may be temporarily wound into a roll by a winder or the like, stored, and then cut by a pulverizer or a cutter. The size of the pre-expanded particles thus produced is preferably about 0.5 to 5 mm as an average particle diameter. The degree of crystallinity of the pre-expanded particles is, as described above, using a general-purpose expansion molding machine, when foam molding is performed under ordinary molding conditions, excellent in the fusion property between particles, high mechanical strength. In consideration of obtaining a foamed molded product, the content is preferably about 8% or less.

Further, in order to prevent the pre-expanded particles still having residual heat from being easily united when producing the pre-expanded particles, the crystallinity is preferably about 1% or more. . The crystallinity of the pre-expanded particles is
Within the above range, it is particularly preferably about 1 to 7%, and more preferably about 1 to 6%.

The degree of crystallinity (%) is measured by using a differential scanning calorimeter (DSC) according to the measuring method described in Japanese Industrial Standards JIS K7121, similarly to the measurement of the crystallization peak temperature described above. From the measured heat of crystallization and heat of fusion, it is determined by the following equation.

[0064]

(Equation 1)

In the formula, the heat of fusion per mole of the completely crystalline PET is 26.9 kJ from the description in the Polymer Data Handbook [published by Baifukan]. Specifically, a predetermined amount of the pre-expanded particles as a measurement sample is filled in a DSC measurement container, and the heat of cold crystallization and the heat of fusion are measured while heating at a rate of 10 ° C./min, From the measurement results,
The crystallinity of the pre-expanded particles is determined based on the above equation.

The bulk density of the pre-expanded particles can be appropriately adjusted in accordance with the density of the foamed article produced by subjecting the pre-expanded particles to in-mold foam molding. The density is preferred. Various additives may be added to the pre-expanded particles. Examples of the additive include, in addition to the foaming agent, a bubble regulator, a flame retardant, an antistatic agent, a colorant, and the like. Further, in order to improve the melting properties of the thermoplastic polyester resin, epoxy compounds such as glycidyl phthalate, acid anhydrides such as pyromellitic dianhydride, and acid anhydrides such as sodium carbonate.
A metal compound of group a or IIa or the like can be added alone or as a mixture of two or more as a modifier. In particular, these modifiers are effective not only to improve the foaming properties of the pre-expanded particles, but also to increase the expansion force of the pre-expanded particles in order to increase the closed cell ratio of the obtained expanded particles.

The foaming agent that can be used in the present invention is roughly classified into a solid compound that decomposes at a temperature equal to or higher than the softening point of the thermoplastic polyester resin to generate gas, and that is vaporized in the thermoplastic polyester resin when heated. It is classified into a liquid, an inert gas which can be dissolved in a thermoplastic polyester resin under pressure, and the like, and any of these may be used. Among them, examples of the solid compound include azodicarbonamide, dinitrosopentamethylenetetramine, hydrazoldicarbonamide, and sodium bicarbonate. As the liquid to be vaporized, for example, propane, n
-Butane, isobutane, n-pentane, isopentane,
Saturated aliphatic hydrocarbons such as hexane, aromatic hydrocarbons such as benzene, xylene and toluene, methyl chloride,
Examples include halogenated hydrocarbons such as Freon (registered trademark), and ether compounds such as dimethyl ether and methyl-tert-butyl ether. Further, examples of the inert gas include carbon dioxide and nitrogen.

The pre-expanded particles are mixed with a blowing agent under high-pressure melting using an extruder as described above, extruded and pre-expanded, and then cut to produce thermoplastic polyester resin pre-expanded particles. In such a case, a foaming agent which vaporizes and foams the molten resin at the moment when the molten resin is extruded from the die of the extruder and uses a blowing agent which takes away the heat of the molten resin, for example, a saturated aliphatic hydrocarbon, a halogenated hydrocarbon or the like is used. Is preferred. These foaming agents are preferable because they act to cool the molten thermoplastic polyester resin and have an effect of suppressing the crystallinity of the pre-expanded particles to be low.

The pre-expanded particles include, for example, a polyolefin resin such as a polypropylene resin, a thermoplastic elastomer such as a polyester resin, and the like, as long as the crystallinity of the thermoplastic polyester resin and the rate of crystallization are not significantly affected. Polycarbonate, ionomer, etc. may be added. As a method of manufacturing a heat insulating layer as a foamed molded article using the pre-expanded particles, a pre-expanded particle is filled in a mold that can be closed but cannot be sealed, and steam is introduced as a heating medium, and the inside of the mold is introduced. A foam molding method is preferred.

As a heating medium at this time, besides steam, hot air, oil, or the like can be used, but steam is most effective for efficient molding. The molded foam may be taken out of the mold after cooling. When performing in-mold foam molding with steam, foam molding may be performed under ordinary molding conditions using a general-purpose foam molding machine as described above. That is, after filling the pre-expanded particles into a mold, first, a low pressure [for example, a gauge pressure of 0.04MP
a)] and blow steam into the mold for a certain time,
Discharge air between particles to the outside. Then, the pressure of the steam to be blown is increased (for example, about 0.08 MPa) to foam the pre-expanded particles in the mold and to fuse the particles together to obtain a foam molded article.

The pre-expanded particles are placed in a closed container in advance, and an inert gas such as carbon dioxide, nitrogen, helium or the like is press-injected thereinto. By maintaining in an atmosphere, the expansion force of the pre-expanded particles during in-mold foam molding in a mold can be further increased, and a good foam molded article can be obtained. In the foam molded article thus obtained, the fusion rate as a reference for the fusion property between the particles is preferably 40% or more, particularly preferably 50% or more, particularly preferably 60% or more, and the fusion rate is within this range. It can be said that it shows exceptionally excellent fusibility.

The crystallinity is preferably about 20 to 40%, especially in consideration of dimensional stability in a high temperature environment. When the degree of crystallinity is less than 20% or more than 40%, in any case, thermal shrinkage due to temperature change becomes large, and there is a possibility that breakage or the like may occur. Further, those having a degree of crystallinity exceeding 40% become brittle, so that the required strength cannot be obtained as described above.

To adjust the degree of crystallinity of the foam molded article to a predetermined value within the above range, various methods can be adopted. For example, if the crystallinity of the foamed molded article after foam molding is lower than the target value, the foamed molded article is not taken out of the mold immediately, but is held in the mold for a while and heat-treated. The degree of crystallinity may be increased by such means.

When the degree of crystallinity of the foam molded article immediately after foam molding is close to the target value, the rise of the degree of crystallinity may be suppressed by rapidly cooling the mold. The crystallinity of the foam is obtained from the heat of cold crystallization and the heat of fusion measured in accordance with the measurement method described in Japanese Industrial Standard JIS K7121, similarly to the crystallinity of the pre-expanded particles described above. The heat-insulating layer as a foamed molded article can be used as a heat insulating container, then decomposed and collected, and reused as pre-expanded particles or the like. By reusing the used foamed article in this way, it is possible to contribute to the effective recycling of resources and the reduction of dust, and it is also possible to reduce the cost of the foamed article.

Hereinafter, the advantages of the present invention will be specifically described with reference to Examples and Comparative Examples of the heat insulating layer. The crystallization peak temperature of the thermoplastic polyester resin used, and the crystallinity of the pre-expanded particles and the foam molded article produced using the same were all measured as described in Japanese Industrial Standard JIS K7121. It was determined from the results measured according to the method.

The content ratio and density of isophthalic acid and / or cyclohexanedimethanol were measured by the following methods. After measuring about 100 mg of a sample for measuring the content of isophthalic acid in a pressure-resistant Teflon container,
Dimethyl sulfoxide 1 for absorption analysis manufactured by Wako Pure Chemical Industries
0 ml and 6m of 5N sodium hydroxide-methanol solution
After the addition of 1), the pressure-resistant Teflon container was placed in a pressure-resistant heating container made of SUS, securely sealed, and then heated at 100 ° C. for 15 hours.

Next, the pressure-resistant heating vessel after heating was cooled to room temperature, and in a state of being completely cooled, the pressure-resistant Teflon vessel was taken out, the content was transferred to a 200 ml beaker, and distilled water was added to about 150 ml. Next, after confirming that the contents were completely dissolved, the content was neutralized to pH 6.5 to 7.5 with hydrochloric acid, and the volume was increased to 200 ml after the neutralization, and further diluted 10-fold with distilled water. It was used as a sample solution.

Next, using this sample solution and the standard solution of isophthalic acid, high performance liquid chromatography (HPLC)
The measurement was performed by the apparatus under the following conditions. As the isophthalic acid standard solution, a solution obtained by dissolving an isophthalic acid reagent manufactured by Tokyo Chemical Industry Co., Ltd. in distilled water was used. Apparatus: Waters HPLC LC-module1 Column: Inertsil ODS-25 manufactured by GL
μm (4.6 × 250) Column temperature: room temperature Pump temperature: room temperature Mobile phase: 0.1% phosphoric acid / acetonitrile = 80/20 Flow rate: 0.5 ml / min Analysis time: 50 minutes Injection volume: 50 μl Detection wavelength: 210 nm Next, a calibration curve was prepared using the peak area of isophthalic acid obtained from the standard solution on the X axis and the concentration on the Y axis, and using the obtained calibration curve, the concentration of isophthalic acid in the sample solution (μg / Ml) was calculated.

From the above concentration, the content (% by weight) of isophthalic acid (IPA) in the thermoplastic polyester resin was calculated using the following equation.

[0080]

(Equation 2)

Measurement of content ratio of cyclohexane dimethanol About 100 mg of a sample was weighed into a pressure-resistant Teflon container, and dimethyl sulfoxide for absorption analysis manufactured by Wako Pure Chemical Industries, Ltd.
After adding 1 l and 6 ml of a 5N sodium hydroxide-methanol solution, the pressure-resistant Teflon container was placed in a pressure-resistant heating container made of SUS, securely sealed, and then heated at 100 ° C. for 15 hours.

Next, the pressure-resistant heating vessel after heating was cooled to room temperature, and in a state of being completely cooled, the pressure-resistant Teflon vessel was taken out, the content was transferred to a 100-ml beaker, and a special-grade reagent methanol was added to about 70 ml. Next, after confirming that the content was completely dissolved, the pH was adjusted to 6.5 to 7.5 with hydrochloric acid.
The sample was neutralized to 5, and the volume was increased to 100 ml after the neutralization.

Next, the sample solution and the cyclohexane dimethanol standard solution were separately collected in 10 ml centrifuge tubes, and the solvent was evaporated to dryness while centrifuging, followed by TMS conversion by Tokyo Chemical Industry Co., Ltd. The solution was added with 0.2 ml and heated at 60 ° C. for 1 hour. The heated liquid was measured using a gas chromatograph (GC) under the following conditions.

Apparatus: Perkin Elmer GC
AutoSystem column: DB-5 (0.25 mmφ × 30 m × 0.25
μm) Oven temperature: 100 ° C (2 minutes)-R1-200 ° C-
R2-320 ° C. (5 minutes) Heating rate: R1 = 10 ° C./min, R2 = 40 ° C./min Analysis time: 20 minutes Injection temperature: 300 ° C. Detector: FID (300 ° C.) Gas pressure: 18 psi A calibration curve is created using the peak area of the TMS compound of cyclohexanedimethanol obtained from the standard solution on the X axis and the concentration on the Y axis, and using the obtained calibration curve, the concentration of cyclohexanedimethanol in the sample solution ( μg / m
l) was calculated.

From the above concentration, the content (% by weight) of cyclohexanedimethanol (CHDM) in the thermoplastic polyester resin was calculated using the following equation.

[0086]

(Equation 3)

Measurement of Density According to the method described in Japanese Industrial Standards JIS K6767, the bulk density (g / c) of the pre-expanded particles is calculated by the following equation.
m ³ ) and the density (g / cm ³ ) of the pipe heat insulating material 1 as a foam molded article were obtained.

[0088]

(Equation 4)

Further, the following tests were performed on the heat insulating layers of the heat insulating containers manufactured in the following Examples and Comparative Examples to evaluate the characteristics. Dimensional stability test In accordance with the method described in Japanese Industrial Standards JIS K6767, the foamed molded articles of the respective examples and comparative examples were measured at 120 ° C. × 24.
The dimensional change per 100 mm due to heating at 100 ° C. × 24 hours and at 80 ° C. × 24 hours was measured.

Measurement of fusion rate After the foamed molded articles of Examples and Comparative Examples were bent and broken in the thickness direction, the number of all foamed particles existing in the fractured surface and the number of foamed particles in which the material itself was broken were The number of particles was counted. Then, a fusion rate (%), which is a reference of the fusion property between the particles, was determined by the following equation.

[0091]

(Equation 5)

Example 1 Thermoplastic polyester resin synthesized by polycondensation reaction of ethylene glycol with isophthalic acid and terephthalic acid [isophthalic acid content: 1.7% by weight, 1,4-cyclohexane Dimethanol content: 0% by weight, crystallization peak temperature: 13
5.0 ° C, IV value: 0.80], 100 parts by weight, pyromellitic dianhydride 0.3 part by weight, sodium carbonate 0.03
Weight part with an extruder [caliper: 65 mm, L / D ratio: 35]
While melting and mixing under the condition of a screw rotation speed of 50 rpm and a barrel temperature of 270 to 290 ° C., butane butane (n) as a foaming agent is supplied from a press-fitting pipe connected in the middle of the barrel.
-Butane / isobutane = 7/3) at a rate of 1.1% by weight, based on the mixture.

Next, a mixture in a molten state was placed in a multi-nozzle die [having a diameter of 0.8
15 nozzles each having a diameter of 15 mm were arranged], but after being extruded through each nozzle and prefoamed, 20 ° C.
In a cooling water bath held at Then, pre-expanded particles were produced by cutting with a pellet cutter while sufficiently removing moisture adhering to the cooled strand-shaped foam. The bulk density was 0.14 g / cm ³ .

Next, the pre-expanded particles are placed in a pressure-tight container, pressurized air is introduced to the container to pressurize the container to 0.5 MPa (gauge pressure), and the container is kept at room temperature for 5 hours. , Put into a foaming tank, introduce steam mixed with air, and adjust the temperature in the foaming tank to 65-7.
Refoamed for 120 seconds at 5 ° C. The pre-expanded particles obtained here were approximately cylindrical with a diameter of 2.5 mm and a length of 2.5 mm, the bulk density was 0.055 g / cm ³ , and the crystallinity was 7.6%.

Next, the pre-expanded particles are used to form a heat insulating layer for a heat insulating container having a shape shown in FIG. 1 and having a length of about 370 mm, a width of about 300 mm, a height of about 180 mm and a maximum thickness of about 40 mm. After filling in a mold and closing the mold, steam with a gauge pressure of 0.04 MPa was introduced into the mold for 25 seconds, and then steam with a gauge pressure of 0.08 MPa was introduced for 45 seconds to expand the pre-expanded particles by heating. At the same time, they were fused.

Immediately after the introduction of steam was completed, the surface temperature of the mold in contact with the foamed molded product was measured and found to be 120 ° C. Then, after maintaining in this state for 180 seconds, it was cooled with water to produce a pipe heat insulating material 1 having the above-mentioned dimensions and shape as a foamed molded product. The density of the obtained pipe heat insulating material 1 was 0.055 g / ml, the crystallinity was 28.1% at the skin portion,
It was 29.6% at the center and the fusion rate was 75%, indicating good fusion properties.

The dimensional change was as follows, and slight shrinkage was recognized. However, the degree of shrinkage was a very small value of 1 mm or less per 100 mm at any temperature, and was excellent in dimensional stability. It was confirmed that. (Dimensional change per 100 mm) 120 ° C. × 24 hours: −0.7 mm 100 ° C. × 24 hours: −0.5 mm 80 ° C. × 24 hours: −0.2 mm <Comparative Example 1> Propylene random copolymer particles ( (Ethylene content: 2.5% by weight, melting point: 143 ° C) 10
0 parts by weight and a 10% by weight aqueous solution of tricalcium phosphate 1
5 parts by weight, 0.2 parts by weight of sodium dodecylbenzenesulfonate, 290 parts by weight of water, and 5 parts by weight of dry ice-like carbon dioxide were heated to 148 ° C. while stirring in a closed vessel, This temperature was maintained for 30 minutes.
At this time, the gauge pressure in the container was 2.2 MPa.

Next, one end of the container was opened while maintaining the pressure with carbon dioxide gas, and the contents were released under atmospheric pressure to foam, thereby producing pre-expanded particles having a bulk ratio of 20 times. Then, the pre-expanded particles were filled in the same mold as used in Example 1 and clamped. Steam was introduced into the mold at a gauge pressure of 0.3 MPa to expand the pre-expanded particles by heating. At the same time, they were fused to produce a heat-insulating layer having the same shape and the same dimensions as in Example 1 having a foaming ratio of 20 times.

The dimensional change of the obtained heat-insulating layer was as follows, and it was confirmed that the heat shrinkage at a high temperature was large and the dimensional stability was insufficient. (Dimensional change per 100 mm) 120 ° C. × 24 hours: −1.9 mm 100 ° C. × 24 hours: −0.4 mm 80 ° C. × 24 hours: +0.1 mm The above results are shown in Table 1.

[0100]

[Table 1]

[0101]

According to the present invention, as described above, the heat insulating layer having extremely excellent heat resistance is interposed between at least the inner body and the outer body of the container body. It can exhibit an excellent use effect that can be handled.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view of a state where a lid is opened.

FIG. 2 is a sectional view of a vent valve.

FIG. 3 is a sectional view showing a modified example of the ventilation valve.

FIG. 4 is a perspective view when ribs are formed.

FIG. 5 is a perspective view showing an example of the connection and fixing of the inner body and the outer body.

FIG. 6 is a cross-sectional view showing another example of fixing and fixing.

[Explanation of symbols]

 Reference Signs List A Adiabatic container 1 Container body 2 Lid 11 Container body inner body 12 Container body outer body 13 Container body heat insulation layer A1 Vent valve A2 Vent valve 111 Rib 111a Circular rib 111b Linear rib 72 Engagement part 82 Engagement part B Deformation prevention part by coupling and fixing means 90 Screw to be coupling and fixing means

Claims (6)

[Claims] 1. A 24-hour, 12-hour molding process in which foamed thermoplastic polyester resin particles are formed in a mold as a heat insulating layer between at least an inner body and an outer body of a container body of a container.
An insulated container comprising a foamed molded product having a heat shrinkage of not more than 1 mm per 100 mm under a condition of 0 ° C. 2. The degree of crystallinity obtained by foaming thermoplastic polyester-based resin foam particles in a mold as a heat insulating layer between at least an inner body and an outer body of a synthetic resin of a container body in a container has a crystallinity of 20 to 40. %, And a foam molding having a fusion ratio of 40% or more is interposed. 3. A thermoplastic polyester resin comprising at least one component selected from the group consisting of isophthalic acid and cyclohexanedimethanol in all the components thereof.
The insulated container according to claim 1, wherein the total amount is in the range of 0.5 to 10% by weight. 4. A vent valve for allowing a one-way air flow when a pressure difference is generated between the inside of the container wall and the outside of a part of the exterior body. 4. The heat-insulating container according to any one of claims 1 to 3. 5. The inner wall body is provided with a rib on an outer wall surface for preventing deformation of the inner body.
5. The heat-insulating container according to any one of 4. 6. The heat insulating container according to claim 1, wherein an outer peripheral surface of the inner body and an inner peripheral surface of the outer body are partially connected and fixed.