JP2000280266A - Core material for thermal insulating material and its preparation and vacuum thermal insulating material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vacuum thermal insulating material that is free from environmental problem such as waste treatment and does not suffer deterioration of performance even in use for a long time. SOLUTION: A top chamber 6 on which a top jig 4 is fitted is set on a bottom chamber 7 on which a bottom jig 5 is fitted in such a way that an outer skin material 2 comprising a kraft paper and with gas permeability in which a foamable urethane raw material is cast is stored in the top jig 4 and the bottom jig. A hermetic space 9 even formed between the top chamber 6 and the bottom chamber 7 and the hermetic chamber 9 is connected with a vacuum pump 10 through a pipe 12. In addition, the inside of the hermetic space 9 is evacuated by suction force of the vacuum pump and both jigs 4 and 5 are held at a specified temp. or higher by means of heaters 8 provided above the top jig 4 and below the bottom jig 5. A urethane foam with an open-cell structure with less remaining parts of closed cells is obtd. by action of vacuum and heating when it is foamed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum heat insulating material used for refrigerators and freezers and a method for producing the same.

[0002]

2. Description of the Related Art In recent years, for the purpose of improving the heat insulating performance of a vacuum heat insulating material, for example, as disclosed in Japanese Patent Application Laid-Open No. 5-65990, a urethane foam obtained by foaming a urethane foam material is used as a core material. A method of manufacturing a vacuum heat insulating material, which is coated with a resin film or the like having no air permeability and depressurized and hermetically sealed the inside, has attracted attention. Hereinafter, JP-A-5-6
The method for manufacturing the vacuum heat insulating material disclosed in Japanese Patent No. 5990 will be described with reference to FIGS.

[0003] As shown in FIG.
A hard urethane foam block 24 is obtained by placing a face material 26 made of a paper or a nonwoven fabric having air permeability on 5 and injecting and foaming a urethane foam material containing a cell communication material therein. Further, the rigid urethane foam block 24 is cut into an arbitrary size to obtain a rigid urethane foam panel 27 as shown in FIG. Then, the rigid urethane foam panel 27 is heated at a high temperature for a long time to evaporate the adsorbed moisture and the like, and is covered with a container 23 made of a metal-plastic laminated film, and the inside is depressurized and sealed, as shown in FIG. Such a vacuum heat insulating material 28 is obtained. In the vacuum heat insulating material 28 manufactured in this manner, the rigid urethane foam panel 27 (core material) has a high open cell rate, so that the heat insulating performance hardly deteriorates with time even for long-term use. Absent.

[0004]

However, in the above-described conventional method for manufacturing a vacuum heat insulating material, a foam communicating agent is mixed into a foamed urethane raw material in order to increase a communicating bubble rate. However, urethane foam blocks are mass-produced. When industrially implemented, depending on the type and amount of the cell communication agent, a large amount of closed cells remain at or near the skin portion of the surface of the rigid urethane foam, so the urethane foam is used as a vacuum heat insulating material. Insulation performance at the time of processing is reduced, and there is a problem that gas is diffused with time from the inside of the remaining closed cells due to use for a long period of time (30 days or more), thereby increasing the internal pressure and deteriorating the heat insulation efficiency. .

[0005] Further, since it is necessary to cut the urethane foam block and process it into a urethane foam panel, the number of working steps for manufacturing the vacuum heat insulating material is increased, which is not only time-consuming and costly, but also increases the production cost. Since a large amount of foam waste and processing dust are generated, there is a problem not only in terms of waste disposal costs but also in terms of environment such as wasteful resources.

The present invention has been made in view of the above-mentioned conventional problems, and has no environmental problems such as waste disposal.
It is an object of the present invention to provide a vacuum heat insulating material whose performance does not deteriorate even for long-term use.

[0007]

According to a first aspect of the present invention, there is provided a method of manufacturing a core material for a heat insulating material, wherein a raw material of urethane foam is foamed by heating. Things.

According to this structure, the foaming of the urethane foam raw material is promoted by the action of heating, and the breakage of closed cells proceeds efficiently.

The method of manufacturing a core material for a heat insulating material according to the second aspect is characterized in that the urethane foam material is foamed by heating it in a reduced-pressure atmosphere.

According to this structure, the foaming of the urethane foam raw material is further promoted by the suction effect of the reduced pressure in addition to the heating effect, and the breaking of the closed cells proceeds efficiently.

According to a third aspect of the present invention, in the method of manufacturing a core material for a heat insulating material, a foamed urethane raw material is poured into a material having air permeability, and the periphery thereof is foamed while maintaining at least a predetermined temperature or higher. It is assumed that.

According to this configuration, since the foamed urethane raw material is fired on the air-permeable material, a core material for a heat insulating material having a small amount of closed cells and a large proportion of open cells can be obtained.

According to a fourth aspect of the present invention, there is provided a method of manufacturing a core material for a heat insulating material, wherein the urethane foam raw material is covered with a gas permeable material and is housed in a foam jig, and then around the foam jig or the foam jig. Is foamed while maintaining at least a predetermined temperature or more.

According to this configuration, during the foaming of the urethane foam raw material, the foaming is performed while maintaining the softened state by the heating action, particularly at the skin portion on the surface where the closed cells are likely to remain, and the vicinity thereof. This facilitates the formation of communicating bubbles.

According to a fifth aspect of the present invention, in the method for manufacturing a core material for a heat insulating material according to the third or fourth aspect, the predetermined temperature is at least 55%.
C. or higher.

According to this configuration, it is possible to obtain a core material for a heat insulating material having an open-cell structure in which the number of closed cells is small.

According to a sixth aspect of the present invention, in the method of manufacturing a core material for a heat insulating material according to the third or fourth aspect, the predetermined temperature is not less than 75 ° C.
It is characterized by a temperature of 0 ° C. or lower.

According to this configuration, the urethane foam raw material is foamed under the optimum temperature condition at which a core material for a heat insulating material having an open-cell structure with little residual closed cells is obtained.

The method for producing a core material for a heat insulating material according to claim 7 is the method for producing a core material for a heat insulating material according to any one of claims 3 to 6, wherein the foamed urethane raw material is poured. It is characterized in that foaming is carried out by reducing the pressure around the material having air permeability or inside or around the foaming jig.

According to this configuration, during the foaming of the urethane foam raw material, the foam is also foamed while receiving the suction effect of the reduced pressure, particularly at the skin portion on the surface where the closed cells are likely to remain, and the closed cells are easily broken. In addition, the formation of communicating bubbles is promoted.

According to a eighth aspect of the present invention, there is provided a method for manufacturing a core material for a heat insulating material according to any one of the fourth to seventh aspects. The size is a predetermined size or a multiple of the predetermined size in the length direction.

According to this configuration, when the internal dimension of the foaming jig is a predetermined dimension, the urethane foam raw material is foamed in the foaming jig to obtain a core material for a heat insulating material having a predetermined dimension. When the internal dimension of the jig is a multiple of the predetermined dimension in the length direction, when the urethane foam material is foamed in the jig, the predetermined dimension is set as one unit. A core material for thermal insulation having a plurality of units in one direction is obtained at a time.

Further, the core material for a heat insulating material according to claim 9 is
A bag having an opening in at least one of the air-permeable material, and after injecting the urethane foam raw material from the opening,
The size after foaming in a foaming jig having a predetermined space in the thickness direction is substantially a predetermined size or a multiple of the predetermined size in the length direction.

According to this configuration, the size of the core material for heat insulating material is determined by the size of the material having air permeability regardless of the internal size of the firing jig. That is, when the size of the material having air permeability is a predetermined size, a core material for a heat insulating material having substantially this predetermined size is obtained, and the material having air permeability is a multiple of the predetermined size in the length direction. At this time, when the predetermined dimension is defined as one unit, a core material for a heat insulating material having a plurality of units in the length direction by the multiple is obtained at a time.

According to a tenth aspect of the present invention, there is provided a method of manufacturing a core material for a heat insulating material according to any one of the third to ninth aspects, or the method of manufacturing the same. The material is kraft paper and the basis weight is 50
１４０140 g / m ² .

According to this structure, the material having air permeability has appropriate strength and moldability, and before the urethane foam is foamed, the foamed urethane raw material is formed of kraft paper which is a material having air permeability. There is no danger of seepage.

[0027] In the method for manufacturing a core material for a heat insulating material according to claim 11, the core material for a heat insulating material according to any one of claims 4 to 10 or the method for manufacturing the same, An inwardly projecting portion is provided, and when the urethane raw material is fired in the firing jig, a depressed concave portion is formed.

According to this structure, a concave portion reflecting the shape of the projecting portion provided on the foaming jig is depressed and formed on the surface of the heat insulating core material obtained by foaming the urethane foam material inside the foaming jig. .

A method of manufacturing a core material for a heat insulating material according to a twelfth aspect of the present invention is the method of manufacturing a core material for a heat insulating material according to any one of the fourth to eleventh aspects or the method of manufacturing the same. The material is formed in a bag shape having an opening in at least one side, and a hole or a notch is provided in the vicinity of the opening or in the other bonding portion of the breathable material.

According to this configuration, for example, a convex portion is provided on the foaming jig, and the convex portion is fitted or attached with a hole or a notch provided in a material having air permeability, whereby Since holes and notches play a role in positioning,
This facilitates the accommodation of the permeable material in the foaming jig, and prevents the movement of the permeable material in the foaming jig.

According to a thirteenth aspect of the present invention, there is provided a method of manufacturing a core material for a heat insulating material according to any one of the third to twelfth aspects. A material having air permeability after curing or a material having air permeability and holes or cuts made in the vicinity thereof.

According to this structure, moisture and gas inside the core material are easily released to the outside from a gas-permeable material or a gas-permeable material and holes and cuts provided near the material.

Further, the vacuum heat insulating material according to claim 14 is
A core material for a heat insulating material according to any one of claims 1 to 13, or a core material for a heat insulating material produced by a method for producing the heat insulating material, is covered with an outer packaging material, and the inside is reduced in pressure and sealed. Things.

According to this structure, the obtained core material can be used as it is or cut out to an appropriate size for use as a vacuum heat insulating material, so that the processing time and labor can be saved.
The amount of waste urethane foam material is reduced, and a vacuum heat insulating material free from environmental problems such as waste treatment can be provided at low cost.

[0035]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a skin material made of kraft paper or the like, all of which have air permeability. First, a procedure for injecting the urethane foam raw material 3 into the outer cover material 2 will be described with reference to FIG. As shown in FIG. 1 (a), the outer skin material 2 is rolled into a cylindrical shape, and the mutually facing surfaces of the overlapping portions are bonded. As a result, an adhesive portion 2c extending in the length direction of the outer skin material 2 is formed substantially at the center of the bottom of the outer skin material 2. Openings 2a, 2a are formed at both ends of the outer cover material 2.

Then, one opening 2a is closed and bonded as shown by the arrow in FIG. As a result, FIG.
As shown in (b), the outer skin material 2 has a substantially rectangular flat portion 2b.
Is formed, and the outer skin material 2 has a bag shape in which the other opening 2a is opened. Next, an appropriate amount of the urethane foam material 3 is injected from the opening 2a of the bag-shaped outer cover material 2. The urethane foam raw material 3 is a mixed raw material composed of an organic polyisocyanate, a polyol, a catalyst, a foam stabilizer, and a foaming agent, and is cured after firing to form a urethane foam.

Next, the structure of an apparatus for manufacturing a core material for a heat insulating material according to the present invention will be described. FIG. 2 is a cross-sectional view at the time of manufacturing the core material for heat insulating material according to one embodiment of the present invention. In FIG.
4 is an upper jig and 5 is a lower jig, which are attached to the upper chamber 6 and the lower chamber 7, respectively. An airtight space 9 is formed in a portion sandwiched between the upper chamber 6 and the lower chamber 7, and the periphery of the upper jig 4 and the lower jig 5 in the airtight space 9 is covered with a heat-resistant insulator. A heater 8 made of a flexible electric heating element is provided. still,
The heater 8 may be embedded in the upper jig 4 and the lower jig 5.

Reference numeral 10 denotes a vacuum pump, and the vacuum pump 10 and the airtight space 9 are connected by a pipe 12. And the pipe 1 branched from the middle of the pipe 12
2a is connected to a reduced-pressure stock tank 11, and the reduced-pressure stock tank 11 is connected by the pipes 12 and 12a.
And the airtight space 9 are communicated. Further, the valve 13 and the pipe 12a branched from the branch point of the pipe 12 on the airtight space 9 side and the branch point, respectively, are provided.
A valve 14 is provided, and these valves 13 and 14 are opened and closed as necessary to open or close the communication between the airtight space 9 and the vacuum pump 10 and the reduced pressure stock tank 11. The decompression stock tank 11
Is previously depressurized by the vacuum pump 10, and the valves 13 and 14 are closed in that state.

The upper jig 4 and the lower jig 5 are provided with a plurality of jig openings 4a and 5a, each having a hole penetrating therethrough and communicating with the pipe 12, and the opening 2a and the flat Jig sealing portions 4b and 5b for fixing the portion 2b therebetween are provided. Instead of providing the jig openings 4a and 5a in the foaming jigs 4 and 5, respectively, the foaming jigs 4 and 5 themselves may be made of a material having air permeability such as ceramic foam.

In the thin part of the urethane foam raw material 3 injected into the outer shell material 2, the calorific value of the heater 8 is reduced or the heater distribution is roughened to reduce the firing jig. The amount of heat transmitted to each part in 4 and 5 may be adjusted according to the temperature conditions required for the part. Further, temperature sensing means are provided at several portions of the firing jigs 4 and 5 close to the outer skin material 2, and the amount of heat generated by the heater 8 is locally adjusted based on temperature information sensed by the temperature sensing means. You may. Thereby, the heat of the heater 8 is appropriately transmitted to the entire urethane foam material 3 in the outer skin material 2, and the foaming of the urethane foam material 3 can be performed stably. Further, instead of the heater 8, a heater in which heated liquid such as water or oil or gas such as steam or air is passed through a pipe may be used.

A procedure for manufacturing a core material for a heat insulating material using the apparatus having the above configuration will be described. First, the outer material 2 is placed such that the opening 2a and the flat portion 2b of the outer material 2 (see FIG. 1B) in which the urethane foam material 3 is injected into the jig sealing portion 5b of the lower jig 5 ride up. Is placed on the lower jig 5. Then, the outer chamber 2 is accommodated in the firing jigs 4 and 5 by setting the upper chamber 6 to which the upper jig 4 is attached to the lower chamber 7. As a result, the jig sealing portions 4b and 5b are kept in the opening 2a and the flat portion 2b until the foaming reaction is completed and the urethane foam raw material 3 is hardened.
Therefore, the urethane foam raw material 3 is in a flat state without intrusion. Therefore, this flat portion 2b
After the core material 1 is completed, it can be easily bent.

The upper chamber 6 and the lower chamber 7
The connection point is sealed in an attachable / detachable manner by an O-ring or the like so that the inside thereof is airtight. Instead of the airtight space 9, the jig openings 4a, 5a of the upper jig 4 and the lower jig 5 are directly connected to the pipe 12,
If the area around the jig including the jig sealing portions 4b and 5b is sealed with an O-ring or the like and the portion where the core material 1 is accommodated is an airtight chamber, the same as above without the upper chamber 6 and the lower chamber 7 can be obtained. A decompression effect can be expected, and the equipment can be further miniaturized. Furthermore, in FIG. 2, the structure is such that the chamber is opened in the vertical direction. However, if the chamber is opened in the horizontal direction while this part is rotated by 90 °, the apparatus requires less installation space.

Further, as shown in FIG. 3, a convex portion 5c is provided in the jig sealing portion 5b of the lower jig 5, and the convex portion 5c is passed through a hole 2d formed in the flat portion 2b of the outer casing material 2. At the same time, by fitting the convex portion 5c into a concave portion 4c provided at a position facing the convex portion 5c of the upper jig 4, the outer skin material 2 can be easily moved to an optimal position inside the firing jigs 4, 5. Not only can it be accommodated, but once the skin material 2 is housed in the foaming jigs 4 and 5, significant movement of the skin material 2 inside the foaming jigs 4 and 5 is prevented. The foaming reaction of the urethane foam raw material 3 can always be performed stably under the same conditions. FIG. 3 shows a case in which a hole 2d is provided in the flat portion 2b of the outer cover 2, but a notch for positioning is provided instead of the hole 2d, and this notch is connected to the protrusion 5c.
May be attached. Further, a positioning hole or notch may be provided near the opening 2a of the outer cover material 2.

Then, near the opening 2a or the flat portion 2b
If the notch or the hole is provided with a groove for the projection 5c in a direction perpendicular to the opening 2a, it becomes easier to set the outer skin material 2 on the lower jig 5. In addition, the assobi is required for the displacement of the outer cover material 2 when the length of the outer cover material 2 is short in a direction perpendicular to the opening 2a due to the firing of the foamed urethane raw material. Has become. Furthermore, the force with which the outer shell 2 is sandwiched between the jig sealing portions 4b and 5b on the side where the outer shell 2 needs to be shifted is such that the outer shell 2 is displaced. The upper jig 4 near the core material 1 other than the jig sealing portions 4b and 5b
When the upper chamber 6 is set in the lower chamber 7, the lower jig 5 may have a small gap so as not to pinch the outer cover 2.

The upper jig 4 and the lower jig 5 are preheated to a predetermined temperature by the heater 8, and are set to maintain the predetermined temperature at least until the foaming reaction of the urethane foam raw material 3 is completed. Have been. In this state, after setting the upper chamber 6 to the lower chamber 7, the vacuum pump 10 is driven to open the valve 13. Then, the urethane foam raw material 3 starts foaming, and the valve 14 is opened at a timing at which the generated bubbles break. In this state, the valve 13 is opened until the foaming of the urethane foam raw material 3 is completed,
The pressure in the hermetic space 9 is continuously reduced by the vacuum pump 10. When the foaming of the urethane foam raw material 3 is completed and hardened to form the urethane foam 3a, the inside of the airtight space 9 is returned to the atmospheric pressure. Then, the upper chamber 6 is removed from the lower chamber 7, and the core material 1 composed of the outer skin material 2 and the urethane foam 3a therein is taken out.

FIG. 4 is a side sectional view of the core material, and FIG. 5 is a sectional view taken along line AA in FIG. In these figures,
1a is a depression, and when the urethane foam raw material 3 expands while foaming, the depression 1a is pressed by the substantially rectangular protrusion 4c provided on the upper jig 4 so that the core 1 is pressed.
It is formed in a rectangular shape reflecting the shape of the protrusion 4c. Further, 1b and 1c are corners of the peripheral edge of the core material 1 and the corners 1b and 1c are used when the urethane foam raw material 3 is foamed.
The outer shell material 2 is formed by the corner portions 1b inside the firing jigs 4 and 5,
A curved surface is obtained by following the rounded shape of the portion corresponding to 1c. That is, the upper jig 4 and the lower jig 5 are formed so that all corners including the concave portion of the core material 1 have an appropriate curved surface.

In the space for accommodating the core 1 formed by the upper jig 4 and the lower jig 5, the dimension in the thickness direction needs to be such that the core 1 has a predetermined thickness. There is
When the strength of the outer covering material 2 overcomes the foaming force of the urethane foam raw material 3, the corners of the upper jig 4 and the lower jig 5 corresponding to the vicinity of the corners of the core material 1 such as the corners 1b and 1c are used as cores. The gap may be formed by a shape having a small radius of curvature different from the curved surface of the material 1. In some cases, even if the corners of the upper jig 4 and the lower jig 5 are formed in an angular shape, the foam In the state after the foaming and curing of the urethane raw material 3, if there is a dimensional relationship between the corners of the foaming jigs 4 and 5 and the outer skin material 2, the corners of the core 1 are finished to a curved surface. .

Also, as described above, the outer shell material 2 and the firing jig 4
By always providing a gap between the urethane foam raw material 3 and the inside of the urethane foam 5, the suction by the vacuum pump 10 can be promoted at the time of foaming the urethane foam raw material 3. That is, since a wide-range decompression effect can be obtained in a short time, the communication bubble structure inside the urethane foam 3a can be further uniformized and the density can be reduced.

As shown in FIG. 1, the outer skin material 2 has an adhesive portion 2c extending in the length direction substantially at the center of the bottom.
The bonding portion 2c may be a state in which the outer skin material 2 made of kraft paper or the like is rolled into a cylindrical shape, and the inner side is overlapped and bonded, and folded near the bonding root to be folded down to one side. This adhesive surface may be provided on at least one end in the length direction or the width direction of the core material. In this case, when the foamed urethane raw material 3 is injected into the inner surface side of the outer skin material 2, the entire periphery of the outer skin material 2 that is in contact with the foamed urethane raw material 3 becomes a single surface with good air permeability at least until immediately before the firing is completed, and In the later urethane foam 3a, communication bubbles are formed more uniformly. Furthermore, mass productivity is improved by attaching a heat-weldable plastic in advance to the outer skin material 2 in the vicinity of the above-mentioned bonding portion and hot-pressing with a roller or the like.

When there is an unnecessary projection or edge on the core material 1 that has been hardened after foaming, it is preferable to hit the portion with a hammer or the like or press it with a pressing die or jig to make it a curved surface, a flat surface, or a concave surface. In addition, there is no possibility that the outer packaging material of the vacuum heat insulating material, which will be described later, is broken at the protrusions and the edge portions. Further, the corner portion of the core material 1 as described above may be formed in a C-plane shape. still,
By providing a gap or a groove between the curved surface of the corner of the core material 1 and the corresponding corner of the upper jig 4 and the lower jig 5, this area becomes a decompression passage, and a wider area can be obtained more quickly. In addition, the pressure can be reduced uniformly, so that the communication bubbles in the core material 1 can be further uniformized and the density can be efficiently reduced.

FIG. 6 is a side sectional view of a vacuum heat insulating material according to one embodiment of the present invention. In FIG. 6, reference numeral 15 denotes an adsorbent for adsorbing and removing a small amount of gas, moisture, or the like generated from inside the core material 1 or entering from outside the vacuum heat insulating material 18.
The adsorbent 15 is sealed in the depression 1a with a pressure-sensitive adhesive tape 16 having air permeability. Reference numeral 17 denotes an outer packaging material made of a substance having a gas barrier property (for example, a non-permeable thin film material formed of a laminate of an aluminum-evaporated polyester film and a metal foil heat-sealable plastic).

The procedure for producing the vacuum heat insulating material 18 having such a configuration will be described. The flat portions 2b, 2b at both ends of the outer covering material 2 of the core material 1 manufactured by the above method are bent upward from the root and shown in the figure. After the core material 1 is fixed to the outer peripheral surface of the outer material 2 with a tape or the like so as to be in close contact with the outer material 2 as shown in FIG.
It is housed in a drying oven at 0 to 130 ° C. for about 2 hours, and the urethane foam 3a in the core material 1 is sufficiently dried by evaporating moisture and gas. Then, after an appropriate amount of the adsorbent 15 is injected into the depression 1a of the core 1 taken out of the drying furnace, the core 16 is sealed with the tape 16 so as to cover the entire depression 1a. Further, this core material assembly has an opening 1 at one end.
The core assembly is sealed in the outer packaging material 17 by packing the outer packaging material 17 into a bag-like outer packaging material 7a and depressurizing the inside of the outer packaging material 17 with a vacuum chamber and heat sealing the opening 17a. The vacuum insulation material 18 obtained is obtained.

As shown in FIG. 6, by bending the flat portion 2b to the side of the outer cover 2 where the recessed portion 1a is formed, the opposite side can be made a flat surface. The vacuum heat insulating material 18 thus provided can be easily attached to an inner flat surface such as an outer wall material of a refrigerator. In addition, if holes or cuts are provided in the outer shell material 2 of the core material 1 after the foamed urethane raw material 3 is foamed and hardened, moisture and gas of the urethane foam 3a are easily discharged to the outside directly from the holes and cuts. Therefore, it is possible to shorten the time required for drying the core material 1 in a drying oven or for wrapping the core material assembly in the outer packaging material 17 and evacuating the inside thereof. In addition, the core 1
Flat portion 2 in the vicinity of the opening 2a and the flat portion of the bonding portion
b, 2b may be removed and used as the core 1. Further, the vicinity of the opening 2a and the flat portion 2b are adhered after the outer cover 2 is folded, so that the jig sealing portions 4b, 5b do not sandwich the outer cover 2. In this case, a flat portion may not be formed in this portion.

If there is a convex portion such as a condensing pipe on the inside of the outer wall material of the refrigerator or the like on which the vacuum heat insulating material is stuck, the outer packing material is attached to the core material of the vacuum heat insulating material on the corresponding side. In consideration of the thickness and the like of the foaming jig, it is easy to form the projections so that the recesses corresponding to the projections and the recesses avoiding the region where the projections are formed are formed on the foaming jig. The recess can be formed in the core material.

Now, the dimensions inside the jig are set to 440 × 700 × 15.
(Mm), kraft paper having a basis weight of 80 g / m ² was used as the skin material 2, and the urethane foam raw material 3 was foam-hardened under various conditions shown in Table 1 below to produce the core material 1. By the way, as an index for evaluating the quality of the urethane foam 3a obtained by foaming the urethane foam raw material 3, the degree of openness of the open cells defined by the following equation is usually used. Table 1 also shows the value of the degree of openness. Opening degree (%) = (V−Q) / V × 100 (1) where V is the space volume (cc) in the heat insulating material, and Q is the generated gas volume (cc) in the heat insulating material. ). Further, the following holds: Q = (P1−P0) × V / 760. Here, P0 is the initial pressure (To) in the heat insulating material.
rr), P1 is the pressure (Torr) after 24 hours in the heat insulating material
r).

When the degree of openness defined by the formula (1) is a low value, a large number of closed cells remain particularly at and near the skin portion which is the surface of the urethane foam 3a. When the foam 3a is used as it is as the core material 1 of the vacuum heat insulating material 18, the residual gas in the closed cells is filled in the vacuum heat insulating material 18 and the degree of vacuum is reduced. Degradation is seen.

[0057]

[Table 1]

The injection amount of the urethane foam raw material 3 was 363 g.
When the jig temperature of the upper jig 4 and the lower jig 5 is set to 30 ° C. and the urethane foam material 3 is foamed without depressurizing the airtight space 9, the urethane foam in the firing jigs 4 and 5. 3a is incompletely filled, the degree of openness is as low as 89.5%, and many closed cells remain in and near the skin portion of the urethane foam 3a and can be used as the vacuum heat insulating material 18. Is about 50% of the whole core material 1
Met.

The injection amount of the urethane foam raw material 3 was set at 28
When the urethane foam material 3 is foamed under the same conditions as described above except that the pressure in the airtight space 9 is reduced to 2 g, the urethane foam material 3 foams throughout the upper jig 4 and the lower jig 5, Although the foam 3a is in a completely filled state, the degree of openness of the open cells is still low at 92.1%.
A considerable amount of closed cells still remain at and near the skin portion of the urethane foam 3a, and the portion that can be used as a vacuum heat insulating material is about 60% of the entire core material 1,
As a result of the reduced pressure in the hermetic space 9, the proportion of the portion that can be used as the vacuum heat insulating material 18 is slightly improved.

That is, when the urethane foam raw material 3 is foamed in the upper jig 4 and the lower jig 5, the pressure in the airtight space 9 is reduced, so that the skin portion where the closed cells are likely to remain and the vicinity thereof are also foamed. Since the closed cells are easily sucked from the inside and the closed cells are easily broken, and the formation of open cells is promoted, the urethane foam 3a having a small portion of the closed cells remaining can be obtained. Further, even if the injection amount of the urethane foam raw material 3 is reduced by as much as 81 g, the urethane foam 3 a
Is completely filled, and urethane foam 3
Since the core material 1 can be obtained with a small amount of raw materials in combination with the low density of a, the amount of foam waste material can be reduced by that much, and a vacuum insulation material that has almost no environmental problems such as waste disposal at low cost Can be provided.

Further, when the urethane foam material 3 is foamed under the same conditions as above except that the jig temperature of the upper jig 4 and the lower jig 5 is set to 75 ° C., the urethane foam material 3 4 and the entire inside of the lower jig 5 were foamed, the urethane foam 3a was completely filled, and the degree of openness of the open cells was improved to 99.8%. As a result, the remaining portion of the closed cells almost disappears, and the core material 1 that can be used as the 100% vacuum heat insulating material 18 by using an appropriate amount of the adsorbent 15
Is obtained.

In other words, by reducing the pressure in the hermetic space 9 and keeping the jig temperature at 75 ° C., especially at the skin portion where closed cells are apt to remain, and the vicinity thereof, the foaming action from outside and the softening action due to heating during foaming. As a result, the closed cells are easily broken, and the formation of open cells is promoted, so that the core material 1 having an open cell structure without any remaining closed cells at almost all locations can be obtained. This core material 1 is used as it is as a vacuum heat insulating material 18.
Since there is no need to cut out a core material of a predetermined size from the urethane foam block as in the past, the labor for processing is reduced by that much, and no foam waste material is produced. It is possible to provide a vacuum heat insulating material capable of reducing costs without the problem described above.

Further, when the urethane foam raw material 3 is foamed under the same conditions as above except that the jig temperature of the upper jig 4 and the lower jig 5 is set to 110 ° C., the degree of openness of the open cells is 99. In this case, the core material 1 which can be used for the 100% vacuum heat insulating material 18 was obtained by using the adsorbent 15 together.

When the jig temperature of the upper jig 4 and the lower jig 5 is set to 55 ° C., the degree of openness of the communication bubble becomes 9
9.1%, and there is a small amount of closed cells remaining at and near the skin portion of the urethane foam 3a. However, by removing this portion, the portion that can be used as the vacuum heat insulating material 18 is about 85% of the entire core material 1. %, And the amount of waste material has been considerably reduced.

By heating the foaming jig until the foaming of the foamed urethane raw material 3 is completed, the raw material foams while maintaining its softening, especially at or near the skin portion where closed cells tend to remain. Are easily broken, and the urethane foam 3a with less residual closed cells is obtained. Therefore, the amount of foam waste material is considerably reduced as compared with the conventional method, and the effect is remarkable when the jig temperature is 55 ° C. or more. When the temperature is 75 ° C. or higher, the core material 1 which can be used as the almost 100% vacuum heat insulating material 18 can be obtained by using an appropriate amount of the adsorbent. The upper limit of the jig temperature is 140 ° C. due to the heat resistance of the urethane material, and the upper limit needs to be 130 ° C. in consideration of variations in quality when industrially implemented.

The outer skin material 2 has a basis weight of 50 g /
When a kraft paper of less than m ² is used, a part of the urethane foam raw material before foaming penetrates the kraft paper and leaks out of the kraft paper, which acts like an adhesive, and after the foaming hardening of the urethane raw material, the core is formed. The material 1 stuck to the foaming jigs 4 and 5, making it difficult to remove the core material 1 from the foaming jigs 4 and 5.

Then, the outer skin material 2 has a basis weight of 140
When kraft paper exceeding g / m ² is used, the outer cover material 2 becomes hard and is inferior in moldability, and moreover, it becomes difficult to conform to the inner shape of the jig, so that the core material 1 having a desired shape cannot be obtained. Furthermore, since the air permeability of the outer skin material 2 also deteriorates, the core material 1
In this case, the pressure-reducing effect at the time of production was reduced, and a problem occurred that a high-quality core material 1 having few closed cells could not be obtained.

That is, the outer skin material 2 has a basis weight of 50 to 1
By using the kraft paper of 40 g / m ^2, the kraft paper can be given appropriate air permeability, and the urethane raw material before foaming can be applied to the foaming jigs 4 and 5 by seeping out to the outside of the outer skin material 2. And the hardness and strength of the kraft paper are suitable for moldability, so that the core material 1 having a desired shape can be easily obtained. Since the periphery of the core material 1 thus obtained is covered with the skin material 2 made of kraft paper, the strength of the core material 1 is maintained at an appropriate level, and the handling of the core material 1 during transport and processing becomes easy. . In the present embodiment, the case where kraft paper is used as the outer skin material 2 has been described. However, the present invention is not limited to this, and a nonwoven fabric or the like may be used.

The dimensions in the jigs of the foaming jigs 4 and 5 in FIG. 2 are determined by using a core material 1 of a predetermined size as one unit.
The dimensions are set so that one core material 1 can be manufactured, but may be a multiple of the unit in the length direction. In this case, by cutting the obtained core material 1 into the predetermined size, a plurality of core materials 1 that can be used for the vacuum heat insulating material can be manufactured at a time, so that productivity can be improved.

The dimensions inside the jigs of the foaming jigs 4 and 5 are set to predetermined dimensions in the thickness direction, while the widths and the lengths of the jigs are set to have a margin. 5
By foaming the urethane foam raw material 3 injected into the outer skin material 2 having a predetermined size inside, the core material 1 having a substantially predetermined size can be obtained. Then, by using a material which is a multiple of the predetermined size in the length direction as the outer skin material 2, when the predetermined size is set to one unit, a plurality of units are provided in the length direction by the multiple. A core material for heat insulating material is obtained at one time. Also in this case, by cutting the core material for heat insulating material composed of the plurality of units into a predetermined size, a plurality of core materials usable for the vacuum heat insulating material can be manufactured at one time.
Productivity can be improved.

Further, an air-permeable material such as kraft paper is spread and placed on a table or the like, and a urethane foam material is poured on the air-permeable material, and then stored in an oven, etc. Vacuum urethane foam raw material is foamed while maintaining the periphery of the urethane foam raw material at a predetermined temperature, and a vacuum heat insulating material is manufactured using a urethane foam cut to a predetermined size as a core material while leaving the material having air permeability. Is also good.
In this case, compared to the case where the urethane foam material is foamed without heating the urethane foam material as in the conventional method,
Since a urethane foam core material with a small amount of closed cells remaining is obtained, the amount of foam waste material is reduced, and there is no environmental problem such as waste treatment, and a vacuum heat insulating material capable of cost reduction can be provided. If a belt conveyor is used instead of the table and the oven is made in a tunnel shape, core materials can be continuously mass-produced. It is also apparent that the same or higher effects can be obtained even when an appropriate amount of a foam-communicating agent is added to the foamed urethane raw material.

[0072]

According to the first aspect of the present invention, foaming can be promoted by heating and foaming the urethane foam material, and the closed cell can be broken. As a result, a core material for a heat insulating material composed of urethane foam having an open-cell structure with few closed cells is obtained.

According to the second aspect of the present invention, the foaming can be promoted by heating the urethane foam raw material in a reduced pressure atmosphere, and the closed cells have a small number of closed cells due to the progress of the breaking of the closed cells. A core material for a heat insulating material comprising urethane foam having a structure is obtained.

Further, according to the third aspect of the present invention, by heating the foamed urethane raw material on the air-permeable material and firing it, heat insulation made of urethane foam having a small amount of closed cells and a large proportion of open cells is achieved. The core material can be obtained at low cost. Such a method of manufacturing a core material does not require a special device, and is thus rich in mass productivity.

According to the fourth aspect of the present invention, the urethane foam produced by storing the urethane foam raw material in the foaming jig and heating the foamed urethane foam, as it is, has a core material for a heat insulating material together with a material having air permeability. Since it can be used as a raw material, the labor for processing can be saved and the foam waste material is not generated, so that a core material for a heat insulating material can be obtained which has no problem not only in the processing cost but also in the environment such as waste treatment.

According to the fifth aspect of the present invention, the foaming reaction can be promoted by firing the foamed urethane raw material at a temperature condition of at least 55 ° C. or higher, and the foaming of the closed cells progresses, and A core material for a heat insulating material having an open-cell structure with few bubbles remaining can be obtained.

According to the sixth aspect of the present invention, the foamed urethane raw material is fired under the temperature condition of 75 ° C. or more and 130 ° C. or less, so that the softened state is maintained particularly at or near the skin portion on the surface where closed cells are easily formed. As the shooting proceeds, the closed cells at the site are easily broken, and the formation of open cells is promoted. Therefore, since all the portions inside the urethane foam have a closed cell structure with few closed cells, a core material for a heat insulating material having excellent quality can be obtained.

According to the seventh aspect of the present invention, when foaming the urethane foam material, the pressure is reduced around the air-permeable material into which the foamed urethane material has been poured or in or around the firing jig. In particular, the skin portion where the closed cells are likely to remain and the vicinity thereof are also sucked from the outside during the foaming, so that the closed cells are easily broken and the open cells are promoted. Therefore, the open-cell structure having few closed cells is obtained at all locations inside the urethane foam, so that a core material for a heat insulating material having excellent quality can be obtained.

According to the eighth aspect of the present invention, the internal dimension of the foaming jig is set to a predetermined dimension or a multiple of the predetermined dimension in the length direction. At this time, by foaming the urethane foam material therein, a core material for a heat insulating material having a predetermined dimension is obtained, and when the internal dimension of the foaming jig is a multiple of the predetermined dimension in the length direction, When the urethane foam material is foamed therein, a core material for a heat insulating material comprising a plurality of units in the length direction by the multiple is obtained when the predetermined dimension is defined as one unit. Therefore, by cutting the core material for heat insulating material composed of a plurality of units into a predetermined size, a plurality of core materials that can be used for the vacuum heat insulating material can be manufactured at one time, and the efficiency of productivity can be improved.

According to the ninth aspect of the present invention, the size of the core material for heat insulating material is determined by the size of the material having air permeability regardless of the internal size of the firing jig. That is, when the size of the material having air permeability is a predetermined size, a core material for a heat insulating material having substantially this predetermined size is obtained, and the material having air permeability is a multiple of the predetermined size in the length direction. At this time, when the predetermined dimension is defined as one unit, a core material for a heat insulating material having a plurality of units in the length direction by the multiple is obtained at a time. Therefore, by cutting the core material for heat insulating material composed of a plurality of units into a predetermined size, a plurality of core materials that can be used for the vacuum heat insulating material can be manufactured at one time, and the efficiency of productivity can be improved.

According to the tenth aspect of the present invention, kraft paper is used as a material having air permeability, and the basis weight is set to 50 to 140 g / m ² , so that the kraft paper has appropriate air permeability. While it is possible, the urethane raw material before foaming does not stick to the foaming jig by exuding to the outside of the kraft paper, and since the hardness and strength of the kraft paper are suitable for moldability,
A core material for a heat insulating material having a desired shape with few closed cells can be obtained. Since the periphery of the core material obtained in this manner is covered with a wrapping material made of kraft paper, the strength of the core material is maintained at an appropriate level, and the handling of the core material during transportation and processing becomes easy.

According to the eleventh aspect of the present invention, the shape of the projecting portion provided on the surface of the heat insulating core material obtained by foaming the urethane foam material inside the foaming jig so as to project inside the foaming jig. Can be depressed and formed without generating cutting chips.

According to the twelfth aspect of the present invention, for example, a convex part is provided on a foaming jig, and a hole or a notch provided in a material having air permeability is fitted or attached to the convex part. By doing so, the holes and notches play a role in positioning, so that a gas-permeable material into which the foamed urethane raw material has been injected can be easily accommodated at an optimum position in the firing jig, and Since the movement of the air-permeable material in the inside is prevented, the quality of the heat insulating core material obtained by foaming the urethane foam raw material is stabilized.

According to the thirteenth aspect of the present invention, the material having the gas permeability after the foaming and curing of the urethane foam raw material or the material having the gas permeability, and the holes and cuts provided near the material, provide the holes. Since the moisture and gas inside the core material are released to the outside directly from the cuts and cuts, the time required for placing the core material in a drying furnace and drying it can be reduced.

According to the fourteenth aspect of the present invention, the obtained core material can be used as it is or cut out to an appropriate size and used as a vacuum heat insulating material, so that the processing time can be saved and urethane foam waste material can be obtained. The amount decreases,
It is possible to provide a vacuum insulation material having no environmental problems such as waste treatment at a low cost. In addition, since this vacuum heat insulating material uses a core material with an open-cell structure in which few closed cells remain, the use of a small amount of adsorbent allows gas to diffuse from inside the core material over a long period of use. A long-life and high-quality vacuum heat insulating material that hardly deteriorates with time due to heat insulation.

[Brief description of the drawings]

FIG. 1 (a) is a perspective view showing a state in which a skin material having air permeability is rolled into a cylindrical shape, and a portion where the lower skin materials overlap each other is adhered. (B) It is a perspective view at the time of injecting a foaming urethane raw material into the bag-shaped outer skin material which closed and adhered one of the openings at both ends of the outer skin material shown in FIG. 1 (a).

FIG. 2 is a cross-sectional view at the time of manufacturing a core material for a heat insulating material according to an embodiment of the present invention.

FIG. 3 is a partially omitted perspective cross-sectional view of a case in which a skin material into which a urethane foam material according to an embodiment of the present invention is injected is housed in a foaming jig.

FIG. 4 is a side cross-sectional view of a core material for a heat insulating material produced by a method for manufacturing a core material for a heat insulating material according to an embodiment of the present invention.

FIG. 5 is a sectional view taken along line AA in FIG. 3;

FIG. 6 is a side sectional view of a vacuum heat insulating material according to one embodiment of the present invention.

FIG. 7 is a cross-sectional view at the time of manufacturing a conventional rigid urethane foam block.

FIG. 8 is a perspective view of a conventional rigid urethane foam panel.

FIG. 9 is a cross-sectional view of a conventional vacuum heat insulating material.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Core material 2 Outer skin material 2a Opening 2b Flat part 3 Urethane foam raw material (before foaming) 3a Urethane foam (after foaming) 4 Upper jig 5 Lower jig 6 Upper chamber 7 Lower chamber 8 Heater 9 Airtight space 10 Vacuum pump 11 Decompression stock tank 12, 12a Pipe 13, 14 Valve 15 Adsorbent 16 Tape 17 Outer packaging 18 Vacuum insulation

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) // B29K 75:00 105: 04 F term (reference) 3H036 AA08 AA09 AB18 AB25 AB28 AC01 3L102 JA00 KA00 MA07 MB13 MB14 MB16 MB23 MB26 4F204 AD06 AD08 AD17 AD18 AE02 AH51 AR06 EA01 EA05 EB01 EB13 EK09 EK13 EK24 EL21 EL24

Claims (14)

[Claims] 1. A method for producing a core material for a heat insulating material, wherein a foamed urethane material is foamed by heating. 2. A method for producing a core material for a heat insulating material, wherein a foamed urethane raw material is foamed by heating in a reduced pressure atmosphere. 3. A method for producing a core material for a heat insulating material, wherein a urethane foam material is poured into a material having gas permeability, and foaming is performed while maintaining the surrounding material at a predetermined temperature or higher. 4. A foaming jig is covered with a gas-permeable material so as to cover the urethane foam raw material, and then foamed while maintaining the periphery or the foaming jig at least at a predetermined temperature or higher. Of manufacturing a core material for heat insulating material. 5. The method according to claim 3, wherein the predetermined temperature is at least 55 ° C. or higher. 6. The method according to claim 3, wherein the predetermined temperature is 75 ° C. or more and 130 ° C. or less. 7. The foaming device according to claim 3, wherein the foamed urethane raw material is foamed by reducing the pressure around the air-permeable material or the inside or around the foaming jig. 3. The method for producing a core material for a heat insulating material according to item 1. 8. The heat insulating material according to claim 4, wherein an internal dimension of the foaming jig is a predetermined dimension or a multiple of the predetermined dimension in a length direction. Manufacturing method of core material. 9. A gas-permeable material is formed into a bag having an opening in at least one side, and after urethane foam raw material is injected through the opening, the material is foamed in a foaming jig having a predetermined space in the thickness direction. A core material for a heat insulating material, wherein a size of the core is substantially a predetermined dimension or a multiple of the predetermined dimension in a length direction. 10. The heat insulating material according to claim 3, wherein the material having air permeability is kraft paper, and the basis weight is 50 to 140 g / m ² . Core material or its manufacturing method. 11. A foaming jig is provided with a protruding portion protruding inside, and a depressed concave portion is formed when urethane foam is fired in the firing jig. The core material for a heat insulating material according to any one of claims 4 to 10, or a method for producing the same. 12. The air-permeable material is formed in a bag shape having an opening in at least one side, and a hole or a notch is provided near the opening or in the other adhesive portion of the air-permeable material. The core material for a heat insulating material according to any one of claims 4 to 11, or a method for producing the same. 13. The air-permeable material obtained by subjecting the urethane foam raw material to foam-hardening, or a material having air permeability, and a hole or a cut formed near the air-permeable material. A core material for a heat insulating material as described in the above or a method for producing the same. 14. A core material for heat insulating material according to any one of claims 1 to 13, or a core material for heat insulating material produced by the method for producing the core material, is covered with an outer wrapping material, and the inside is depressurized and sealed. A vacuum insulation material characterized by the above.