JP2016064845A - Bag body and vacuum heat insulation material using the bag body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bag body and a vacuum heat insulation material which can suppress a penetration amount of gas entering inside the bag body, and suppress occurrence of fracture in a heat seal area.SOLUTION: A bag body 2 is formed by overlapping two composite films 20 having heat fusion layers so that the heat fusion layers face each other, and thermally sealing at least a part of an outer peripheral edge part. A row 28 of recesses, in which a plurality of recesses 26 whose thickness of the heat fusion layers is thinner than the periphery are disposed at intervals in a lengthwise direction of a heat seal area 22 formed at the outer peripheral edge part, are provided on at least one surface of the heat seal area 22. A plurality of rows 28 of the recesses are arranged at intervals in a width direction of the heat seal area 22. In each row 28 of the recesses, a recess 26 is arranged so as to be positioned between two recesses 26 of the adjacent rows 28 of the recesses. In a vacuum heat insulation material 1, a core material 10 having a fine gap is sealed in a decompressed state in the bag body 2 as a filling material.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a bag body for sealing a filling material and a vacuum heat insulating material using the bag body.

  In recent years, food such as confectionery and medicines can be stored in a sealed state in a bag to enable long-term storage, or foam, powder, fiber, etc. can be vacuum-sealed into a bag to form a vacuum insulation material. The sealing technology is widely used.

  For example, the vacuum heat insulating material contains a core material excellent in heat insulating properties having fine voids such as glass wool or silica powder in a bag made of a composite film having gas barrier properties, and the inside of the bag is decompressed and sealed. Is. The vacuum heat insulating material achieves a high heat insulating effect by keeping the inside of the bag body at a high vacuum. Therefore, in order to exhibit the excellent heat insulation effect over a long period of time, it is necessary to maintain a high degree of vacuum in the bag body.

  Here, as one of the methods for keeping the inside of the bag body at a high vacuum, there is a method for suppressing the amount of gas (gas) entering the inside from the outside of the bag body. A bag body is usually manufactured by stacking two rectangular composite films and heat-sealing their four side edges (outer peripheral edges). In general, a composite film is composed of a surface protective layer located on the outermost surface, a heat fusion layer located on the innermost surface as a heat sealing material, and a gas barrier layer sandwiched between the base layer and the heat fusion layer. And each of these layers is bonded by an adhesive. Here, the heat-sealing layer is exposed at the end face of the outer peripheral edge of the bag. Gas (gas) permeates through the heat-fusion layer through the heat-fusion layer from the location where the heat-fusion layer is exposed, because the gas (gas) is more permeable than the gas barrier layer. . As a result, the degree of vacuum in the bag body is lowered, and there is a problem that the vacuum heat insulating material cannot maintain excellent heat insulating performance for a long time.

  Therefore, in Patent Document 1, a part of the outer peripheral edge of the bag body is strongly pressed at the time of heat sealing to form a thin part having a small thickness in a part of the heat sealing region. A technique for suppressing the permeation amount of an invading gas (gas) is disclosed. In patent document 1, this thin part is formed so that it may extend linearly, and it is formed so that the perimeter of a bag body may be surrounded.

JP 2011-207664 A

  However, if a thin portion having a small thickness is continuously provided in the heat seal region, the strength of the heat seal region is reduced in the thin portion. Therefore, since the weak part is continuously provided in the heat seal region, there is a possibility that a problem may occur in durability. This problem is not limited to the vacuum heat insulating material, but is the same in other sealed bags.

  The present invention has been made to solve the above problem, and even if a thin portion that suppresses the permeation amount of gas (gas) entering the bag body is provided in the heat seal region, the heat seal region is broken. It is an object of the present invention to provide a bag body having a high sealing property and a vacuum heat insulating material with excellent heat insulating performance.

  The above object of the present invention is to provide a bag formed by stacking two composite films having a heat fusion layer so that the heat fusion layers face each other and heat-sealing at least a part of the outer periphery. The at least one surface of the heat seal area formed on the outer peripheral edge has a plurality of recesses in which the thickness of the heat-sealing layer is thinner than that of the periphery. The recesses are arranged at intervals in the length direction of the heat seal area. A plurality of rows of recesses are provided at intervals in the width direction of the heat seal region, and each row of recesses includes two recesses of the row of recesses adjacent to each other. This is achieved by a bag that is positioned between the two.

  In a preferred embodiment of the bag body configured as described above, the row of the recesses is provided on both surfaces of the heat seal region of the bag body, and the positions of the recesses coincide on both surfaces of the heat seal region. ing.

  In a further preferred embodiment of the bag body configured as described above, the concave portion has the same shape as the concave portion provided to face the opposite surface of the heat seal region of the bag body. In this case, the concave portion has two heat seal bars having a flat plate portion and a plurality of protruding portions projecting from the flat plate portion arranged on one side and the other side of the bag body, and the protruding portion Preferably, the bag is sandwiched between two heat seal bars and heated and compressed in a state where the positions are matched.

  In a further preferred embodiment of the bag having the above-described configuration, the shape of the concave portion is a quadrangular frustum shape whose outer shape gradually decreases toward the bottom surface.

  Further, in a further preferred embodiment of the bag body configured as described above, the corner between the side surface and the bottom surface of the recess is rounded.

  The above-mentioned object of the present invention can also be achieved by a vacuum heat insulating material in which a core material having fine voids as a filling material is sealed under reduced pressure in a bag body having the above-described configuration.

  According to the present invention, the permeation amount of gas (gas) entering the bag body can be suppressed and the occurrence of breakage of the heat seal region can be suppressed, so that the sealing performance of the bag body can be maintained over a long period of time. Can be kept high. Therefore, the vacuum heat insulating material using this bag can maintain excellent heat insulating performance over a long period of time.

It is a top view of the vacuum heat insulating material using the bag of one embodiment of the present invention. It is sectional drawing which follows the AA line of FIG. It is sectional drawing of a composite film. It is a top view which expands and shows a part of heat seal area | region of FIG. It is a top view of a recessed part. It is sectional drawing of a recessed part. It is a top view of a heat seal bar. It is sectional drawing which follows the BB line of FIG. It is explanatory drawing which shows the measuring method of a tension test.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. In the following embodiments, a vacuum heat insulating material will be described as an example. Vacuum insulation materials can be used suitably for insulation of home appliances, heat insulation / cooling equipment, vending machines, etc., and can be used particularly well for insulation of materials that require long-term durability, such as transportation equipment for automobiles and ships, and building materials for housing. .

  FIG. 1 is a plan view of a vacuum heat insulating material 1 using a bag body 2 according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of the vacuum heat insulating material 1 of FIG.

  The vacuum heat insulating material 1 is obtained by sealing a core material 10 as a filling in a bag 2 under reduced pressure. The shape of the core material 10 is usually a plate shape. Although it does not specifically limit as the core material 10, For example, foams, such as urethane foam, a styrene foam, a phenol foam, fiber bodies, such as glass wool, rock wool, an alumina fiber, a silica alumina fiber, pearlite, a silica, etc. The porous powder can be used. Among these, glass wool (preferably fiber diameter of 3 μm to 5 μm) is preferable. The core material 10 preferably has a high porosity (for example, about 90% or more). Further, an adsorbent that adsorbs volatile components or the like may be enclosed inside the bag body 2. As such an adsorbent, for example, activated carbon, zeolite or the like can be used. The shape and size of the vacuum heat insulating material 1 may be the same as that of the conventional vacuum heat insulating material, for example, a plate shape of 10 cm to 150 cm × 10 cm to 200 cm × 1 cm to 5 cm.

  In the present embodiment, the bag body 2 is composed of two rectangular composite films 20 having the same shape in plan view, and these composite films 20 are overlapped to form four side edges 20A to 20D (outer peripheral edges). Part) is heat-sealed to form an internal space 21 for containing the filler in the central part and a heat-seal area 22 for sealing the internal space 21 at the outer peripheral edge part. In addition, the outer peripheral edge part (side edge part 20A-20D) of the composite film 20 has pointed out the predetermined part inside the outer peripheral edge (side edge) which makes the outline of the composite film 20. FIG.

  As shown in FIG. 3, the composite film 20 includes a surface protective layer 23 serving as a surface base material of the composite film 20, a heat sealing layer 24 positioned on the innermost surface of the composite film 20 as a heat sealing material, and a surface protective layer. 23 and a gas barrier layer 25 sandwiched between the heat-fusible layer 24. These layers 23 to 25 are bonded to each other with, for example, a conventionally known laminating adhesive to form the composite film 20. In addition, each layer 23-25 can also be laminated | stacked by extrusion lamination or dry lamination, and the composite film 20 can also be formed.

  The surface protective layer 23 has a function of protecting the gas barrier layer 25 and / or a function of imparting mechanical strength to the composite film 20. For example, a polyamide resin (for example, nylon), a polyolefin resin (for example, a polyethylene resin, Polypropylene resin), cyclic polyolefin resin, polystyrene resin, acrylonitrile-styrene copolymer (AS resin), acrylonitrile-butadiene-styrene copolymer (ABS resin), poly (meth) acrylic resin, polycarbonate resin, polyvinyl alcohol resin, ethylene -Resin selected from saponified vinyl ester copolymer (EVOH resin), polyester resin (for example, polyethylene terephthalate, polyethylene naphthalate), polyurethane resin, acetal resin, and cellulose resin Irumu can be suitably used. Such a resin film can be an unstretched film or a film stretched in a uniaxial direction or a biaxial direction.

  The heat-sealable layer 24 may be a resin film having a heat-sealability that melts by heating and adheres to each other. For example, a linear low-density polyethylene film (LLDPE film) or a polypropylene film (CPP film) Etc. can be used suitably. These resin films may be unstretched or may be stretched.

  The gas barrier layer 25 has a function of blocking gas (gas barrier properties). For example, a metal foil such as an aluminum foil, a copper foil, and a stainless steel foil, or a resin film such as a polyethylene terephthalate film is coated with aluminum or silicon oxide. A thin film made of alumina or the like laminated by vapor deposition or the like can be preferably used.

After the two composite films 20 having the above-described configuration are overlapped so that the heat-sealing layer 24 faces each other, the three side edge portions 20A to 20C excluding the upper side edge portion 20D will be described later. It is set as the bag body 2 by heat-sealing using the heat seal bar 11 shown in FIG.7 and FIG.8. And the core material 10 which is a filling is accommodated in the bag body 2 from the opening in the upper side edge portion 20D which is not heat-sealed, and then dried by heating at atmospheric pressure in a vacuum chamber, After drying by heating under reduced pressure (preferably 1.0 × 10 ^{−2 to} 1.0 × 10 ⁻⁴ Pa, more preferably 1.0 × 10 ^{−3 to} 1.0 × 10 ⁻⁴ Pa), The vacuum heat insulating material 1 can be manufactured by sealing the bag body 2 by heat-sealing the opening using the heat seal bar 11 shown in FIGS. 7 and 8 while maintaining the reduced pressure.

  As shown in FIGS. 1, 2, and 4 to 6, a thin concave portion 26 is formed in the heat sealing region 22, which is a portion where the heat sealing layers 24 facing each other of the two composite films 20 are heat sealed. A plurality are provided. The recessed portion 26 does not extend in a linear shape continuous in the length direction of the heat seal region 22 (the circumferential direction of the bag body 2), like the thin wall portion cited in the prior art document of the present specification, but individually. The plurality of separated recesses 26 are intermittently arranged at intervals along the length direction of the heat seal region 22. The concave portion 26 is formed by strongly pressing a part of the outer peripheral edge portion of the bag body 2 at the time of heat sealing so that the thickness of the heat-sealing layer 24 becomes thinner than the periphery at the pressed portion. As a result, the heat seal region 22 has a thick protrusion 27 having a large thickness of the heat fusion layer 24 and a thin thickness of the heat fusion layer 24 along the length direction of the heat seal region 22. The recesses 26 are alternately arranged.

  As described above, in the present embodiment, a plurality of recess rows 28 are provided in which the recesses 26 are arranged at intervals in the length direction of the heat seal region 22. At least two rows are arranged at intervals along the width direction of 22. In addition, the number of the row | line | columns 28 of the recessed part arrange | positioned has preferable 3 rows or more, and is 4 rows in this embodiment. Furthermore, each row of recesses 28 is arranged such that the recesses 26 are located between two recesses 26 in the row of adjacent recesses 28. That is, each recess row 28 may overlap with the recess row 28 adjacent in the width direction of the heat seal region 22, but the recess 26 may partially overlap in the length direction of the heat seal region 22. It arrange | positions so that it may slip | deviate to the length direction of the heat seal area | region 22 so that it may not overlap. As a result, the heat seal region 22 has a thick protrusion 27 having a large thickness of the heat sealing layer 24 and a thin thickness of the heat sealing layer 24 even in the width direction of the heat sealing region 22. The recesses 26 are alternately arranged, and the plurality of recesses 26 are arranged in a staggered manner as a whole.

  As described above, when the plurality of recesses 26 are arranged in the heat sealing region 22 in which the heat-sealing layers of the outer peripheral edge portions of the bag body 2 are heat-sealed, in the recess 26, the outer peripheral edge portion of the bag body 2 is The area (cross-sectional area) through which the gas (gas) entering from the end face can permeate is reduced, the permeation resistance of the gas (gas) is increased, and the permeation speed is reduced. As a result, the amount of gas (gas) that permeates through the heat seal region 22 and enters the bag body 2 with time is suppressed. Here, in the longitudinal direction of the heat seal region 22, each row of recesses 28 has a portion of a projection 27 where the recess 26 does not exist. In this projection 27, the end surface of the outer peripheral edge of the bag body 2. The gas (gas) that enters from the air easily penetrates. However, since there is a recess 26 in the row 28 of adjacent recesses on the side of the width 27 of the heat seal region 22 of the protrusion 27, the gas entering from the end surface of the outer peripheral edge of the bag body 2 ( The gas) always strikes the recess 26 when passing through the heat seal region 22 in the width direction. Therefore, since the amount of gas (gas) entering from the end surface of the outer peripheral edge of the bag body 2 in the entire region of the heat seal region 22 (the entire circumference of the bag body 2) can be suppressed, the bag body 2 with high sealing performance is provided. can do. On the other hand, in the recessed part 26 of the heat seal area | region 22, the thickness of the heat sealing | fusion layer 24 becomes thinner than the periphery, and intensity | strength falls by the part for the reduction | decrease in the thickness. However, since the recess 26 is provided intermittently in the length direction of the heat seal region 22 and the low strength portion is not continuous, the heat seal region 22 is not easily broken. Therefore, the durability of the heat seal region 22 is increased, and the sealing performance of the bag body 2 can be maintained high over a long period of time. When the bag body 2 is used for the vacuum heat insulating material 1, excellent heat insulating performance is realized over a long period of time. be able to.

  The distance D1 between the recesses 26 constituting the recess rows 28 is not particularly limited, but must be the same as the length 11 of the recesses 26 or less than the length 11 and less than the length 11 of the recesses 26. Preferably there is. As a result, each recess 26 in each recess row 28 overlaps at least partly with any of the recesses 26 in the recess row 28 adjacent in the width direction of the heat seal region 22. Permeation of gas (gas) entering from the end face of the outer peripheral edge can be effectively suppressed. The distance D2 between the recess rows 28 is not particularly limited, and is set as appropriate according to the size of the recess 26, the width of the heat seal region 22, the number of the recess rows 28 provided in the heat seal region 22, and the like. do it.

  The shape of the concave portion 26 is not particularly limited in a plan view, such as a rectangular shape such as a square shape or a rectangular shape, a polygonal shape, a circular shape, or an elliptical shape, but is preferably a rectangular shape. Further, the cross-sectional view shape of the recess 26 is not particularly limited to a triangular shape such as a square shape or a rectangular shape, a trapezoidal shape, a semicircular shape, or a semielliptical shape unless the shape is a pointed shape such as a triangular shape. Although it is not a thing, it is preferable that it is trapezoid shape. Therefore, in this embodiment, the shape of the recessed part 26 is formed in the shape of a quadrangular pyramid which becomes small gradually as it goes to the bottom surface side. As a result, the angle between the four side surfaces 26A and the bottom surface 26B of the concave portion 26 becomes an obtuse angle and becomes gentle and approaches a rounded shape, so that the same size as in the case where the corner is sharply sharpened. The temperature conditions, pressure conditions, and time conditions during heat sealing when forming the recesses 26 can be relaxed. Therefore, even if the temperature or pressure of the heat seal bar 11 is lowered or the pressing time by the heat seal bar 11 is shortened, the recess 26 is clearly formed in the heat seal region 22 of the outer peripheral edge of the bag body 2. Therefore, the energy efficiency at the time of heat sealing can be improved, and the number of products (manufacturing efficiency) within a certain time can also be improved.

  The size of the concave portion 26, that is, the length l1, the width l2, and the depth d are not particularly limited. The width and length of the heat sealing region 22, the number of the concave portions 26 provided in the heat sealing region 22, and the like. What is necessary is just to set suitably according to. The shape of the recesses 26 may all be the same shape, but may be obviously different shapes. For example, the shape of the recesses 26 in the row 28 of recesses on both sides is between them. It may be different from the shape of the recesses 26 of the row 28 of sandwiched recesses. The “same” shape described above is not only completely the same, but also includes a concept that is not perfect but close to it.

  This recessed part 26 is formed by heat-pressing the outer peripheral edge part of the bag body 2 with the metal heat seal bar 11 shown in FIG.7 and FIG.8. The heat seal bar 11 has a flat plate portion 12 and a protruding portion 13 protruding from the flat plate portion 12. In the outer peripheral edge of the bag body 2, the melted heat-sealable layer 24 flows to the periphery at the location pressed by the protrusion 13, so that a recess 26 is formed in which the thickness of the heat-sealable layer 24 is thinner than the periphery. Is done. At this time, since the shape of the recessed portion 26 follows the shape of the protruding portion 13, the shape of the protruding portion 13 of the heat seal bar 11 is a truncated pyramid shape, so that the recessed portion 26 having a truncated pyramid shape is formed. As in the present embodiment, when the shape of the protrusion 13 is a truncated pyramid shape, the corner between the top surface 13A of the protrusion 13 and the four side surfaces 13B serving as the peripheral surfaces is rounded. It is preferable that it is chamfered. Thus, when the corners of the protrusion 13 forming the recess 26 are rounded, the protrusion 13 of the heat seal bar 11 is strongly pressed against the surface protective layer 23 of the composite film 20 during heat sealing. It is possible to reduce the occurrence of damage or the occurrence of damage (pinholes, cracks, etc.) in the metal layer of the gas barrier layer 25. This is because the resin of the heat sealing layer 24 melted at the time of heat sealing easily flows, and the stress of the metal layer of the surface protective layer 23 or the gas barrier layer 25 is relieved. If the surface protective layer 23 of the composite film 20 or the metal layer of the gas barrier layer 25 is damaged during heat sealing, the gas barrier property of the bag body 2 itself is deteriorated even if the gas barrier effect is enhanced by the uneven shape that has been applied. In this embodiment, this problem can be solved satisfactorily. In addition, also when the shape of the projection part 13 is made into square prism shapes, such as a square pole, the same effect is show | played by chamfering a corner | angular similarly. In addition, when the shape of the protrusion 13 is a quadrangular pyramid shape, the inclination angle θ of the four side surfaces 13B inclined toward the top surface 13A is not particularly limited, and is appropriately set (for example, 45 degrees). can do.

  Moreover, in this embodiment, the row | line | column 28 of a recessed part is provided in both surfaces of the heat seal area | region 22 of the outer peripheral edge part of the bag body 2, and the position of each recessed part 26 is both surfaces of the heat seal area | region 22. It corresponds. Moreover, each recessed part 26 is the same shape as the recessed part 26 provided opposite to the surface on the opposite side of the heat seal area | region 22, ie, the recessed parts 26 corresponding on both surfaces of the heat seal area | region 22 are the same shape. It is. The “same” shape described above is not only completely the same, but also includes a concept that is not perfect but close to it. The heat seal bar 11 having the protrusion 13 shown in FIGS. 7 and 8 is disposed on the one surface side and the other surface side of the bag body 2, and the positions of the protrusions 13 of the two heat seal bars 11 are matched. Thus, the concave portions 26 are formed on both surfaces of the heat seal region 22 of the bag body 2 by heating and compressing so that the bag body 2 is sandwiched between the two heat seal bars 11. Thus, when the recessed part 26 is formed in both surfaces of the heat sealing area | region 22 of the bag body 2, respectively, compared with the case where the recessed part 26 is formed only in one surface of the heat sealing area | region 22 of the bag body 2, the temperature at the time of heat sealing Conditions, pressure conditions, and time conditions can be relaxed, the temperature and pressure of the heat seal bar 11 can be lowered, and the pressing time by the heat seal bar 11 can be shortened. Therefore, energy efficiency at the time of heat sealing can be effectively improved, and manufacturing efficiency can also be effectively improved. In addition, when forming the recessed part 26 only in one surface of the heat seal area | region 22 of the bag body 2, the heat seal bar 11 which has the projection part 13 shown in FIG.7 and FIG.8 is arrange | positioned on the one surface side of the bag body2. And the metal heat seal bar which has only a flat plate part is arrange | positioned in the other surface side, and it heat-compresses so that the bag body 2 may be pinched | interposed with both heat seal bars.

  According to the bag body 2 having the above-described configuration, first, the thin concave portion 26 having a thin thickness of the heat sealing layer 24 is formed in the heat sealing region 22 where the heat sealing layers 24 of the outer peripheral edge of the bag body 2 are heat sealed. By providing, the penetration | invasion amount of the gas (gas) which permeate | transmits the heat seal area | region 22 from the end surface of the outer peripheral edge part of the bag body 2, and penetrate | invades in the inside of the bag body 2 is suppressed. Therefore, the sealing property of the bag body 2 can be maintained high, and the vacuum heat insulating material 1 that maintains excellent heat insulating performance can be provided.

  Moreover, since the recessed part 26 was intermittently provided in the length direction (circumferential direction) of the heat seal area | region 22 of the bag body 2, compared with the case where a recessed part is provided in the heat seal area | region 22 continuously in linear form. As a result, the durability of the heat seal region 22 is increased, and the heat seal region 22 is not easily broken. Therefore, since the sealing performance of the bag body 2 can be kept high over a long period of time, the vacuum heat insulating material 1 can also achieve excellent heat insulating performance over a long period of time.

  Moreover, since the recessed part 26 is provided in both surfaces of the heat sealing area | region 22 of the bag body 2, and the heat sealing layer 22 has a thin part in the heat sealing area | region 22 by the two recessed parts 26, heat sealing is carried out. The temperature, pressure, and time conditions can be relaxed. Therefore, in addition to the energy efficiency at the time of heat sealing, manufacturing efficiency can be improved effectively.

  As mentioned above, although one Embodiment of this invention was described, the specific aspect of this invention is not limited to the said embodiment. For example, in the above-described embodiment, the seal region 22 having the recess 26 is provided in all of the four side edge portions 20A to 20D of the bag body 2, but one side edge portion (for example, the upper side) serving as the opening portion of the bag body 2 is provided. The heat seal region 22 having the recess 26 is provided in the three side edges 20A to 20C of the bag body 2 excluding the side edge 20D), and the recess 26 is provided in the side edge 20D serving as the opening of the bag body 2. You may make it provide the heat seal area | region 22 which does not have.

  Moreover, in the said embodiment, although the vacuum heat insulating material 1 which makes the inside of the bag body 2 vacuum was demonstrated, also in the medical use which encloses a chemical | medical agent etc. in the inside of the bag body 2 as uses other than the vacuum heat insulating material 1. It can be implemented in the same manner and the same effect can be expected.

  The present invention will be further described below using examples. However, the present invention is not limited to this embodiment.

[Production of Composite Film of Example]
First, a biaxially stretched polyamide film (Unitika, Emblem NX, thickness 15 μm) was bonded to a biaxially stretched polyethylene terephthalate film (Unitika, polyester film Emblet S, thickness 12 μm) by a dry laminating method. Thereafter, an aluminum foil (Nihon Foil Co., Ltd., JIS8021, thickness 6.5 μm) is bonded to the outer surface of the polyamide film by the same dry laminating method, and a heat fusion layer is further bonded to the outer surface of the aluminum foil by the dry laminating method. As above, an unstretched linear low density polyethylene film (Mitsui Chemicals, Inc., TUX-HC, thickness 50 μm) was bonded. In the dry laminating method in which these four films are bonded together, Takelac A1143 (Mitsui Chemicals, terminal epoxy modification) is used as the main component of the dry laminating adhesive, and Takenate A-3 (Mitsui Chemicals) is used as the curing agent. After mixing at a ratio of 1 and diluting with ethyl acetate to a solid content of 23%, it was applied to one film surface with a gravure cylinder in an amount of 13 g / m ² . After that, an adhesive layer having a solid content of 3.0 g / m ² is formed by passing through a drying furnace, and heat is applied to the surface of the adhesive layer using a laminating roll at about 25 ° C. to 70 ° C. The films were bonded together. Thereafter, aging was performed at atmospheric pressure and 40 ° C. for 168 hours to accelerate the adhesive curing reaction, thereby obtaining a composite film.

[Example 1]
Two rectangular composite films produced as described above are placed so as to face each other so that the polyethylene films face each other, and are laminated using a BH60 bag making machine (manufactured by Totani Giken Kogyo Co., Ltd.). A heat seal bar with a width of 20 mm is arranged on the upper and lower sides of the three side edges of each of the above, sandwiching the three side edges of the composite film with the upper and lower heat seal bars while applying heat of about 180 ° C., Heat-seal polyethylene films. Thereby, a bag body in which the three side edges of 280 mm × 350 mm were heat-sealed was manufactured. This bag was placed in a vacuum drying oven, dried at 80 ° C. for 72 hours, and then glass wool made by Asahi Fiber Glass Co., Ltd. formed into a plate shape of 200 mm × 200 mm × 32 mm (fiber diameter 4 μm). After further drying at 169 ° C. for 36 minutes, the pressure was reduced to 1.0 × 10 ⁻³ Pa, and the opening at the other side edge of the bag was maintained with a 20 mm wide heat seal bar while maintaining the reduced pressure. A vacuum heat insulating material was manufactured by heat fusion at 180 ° C. In Example 1, as a heat seal bar, as shown in FIGS. 7 and 8, a heat seal bar in which a plurality of quadrangular pyramid-shaped projections are provided in the length direction and in a plurality of rows in the width direction as shown in FIG. 7 and FIG. Was used.

[Example 2]
As the upper and lower heat seal bars, as shown in FIG. 7 and FIG. 8, a heat seal bar in which a plurality of quadrangular pyramid-shaped protrusions are provided in the length direction and in a plurality of rows in the width direction as shown in FIGS. A vacuum heat insulating material of Example 2 was produced in the same manner as in Example 1 except that heat fusion was performed while applying heat at about 210 ° C.

[Example 3]
As the upper and lower heat seal bars, a heat seal bar having a plurality of square columnar projections in the length direction and a plurality of rows in the width direction on the flat plate portion, and a heat seal bar having only the flat plate portion, about 210 ° C. A vacuum heat insulating material of Example 3 was produced in the same manner as in Example 1 except that the heat fusion was performed while applying the heat.

[Comparative Example 1]
The vacuum heat insulating material of Comparative Example 1 was used in the same manner as in Example 1 except that heat sealing bars having only flat plate portions were used as the upper and lower heat sealing bars, and heat fusion was performed while applying heat at about 210 ° C. Manufactured.

[Comparative Example 2]
A biaxially stretched polyamide film (Unitika, Emblem NX, thickness 25 μm) was bonded to a biaxially stretched polyamide film (Unitika, Emblem NX, thickness 15 μm) by a dry laminating method. Thereafter, an aluminum foil (Nihon Foil Co., Ltd., JIS8021, thickness: 9.0 μm) is bonded to the outer surface of the polyamide film by the same dry laminating method, and a heat fusion layer is further bonded to the outer surface of the aluminum foil by the dry laminating method. A high-density polyethylene film (Tamapoly Co., Ltd., HD, thickness 50 μm) was attached. In the dry laminating method in which these four films are bonded together, Takelac A1143 (Mitsui Chemicals, terminal epoxy modification) is used as the main component of the dry laminating adhesive, and Takenate A-3 (Mitsui Chemicals) is used as the curing agent. After mixing at a ratio of 1 and diluting with ethyl acetate to a solid content of 23%, it was applied to one film surface with a gravure cylinder in an amount of 13 g / m ² . After that, an adhesive layer having a solid content of 3.0 g / m ² is formed by passing through a drying furnace, and heat is applied to the surface of the adhesive layer using a laminating roll at about 25 ° C. to 70 ° C. The films were bonded together. Thereafter, aging was performed at atmospheric pressure and 40 ° C. for 168 hours to accelerate the adhesive curing reaction, thereby obtaining a composite film.

Two rectangular composite films produced as described above are placed so as to face each other so that the polyethylene films face each other, and are laminated using a BH60 bag making machine (manufactured by Totani Giken Kogyo Co., Ltd.). A heat seal bar with a width of 20 mm for each of the three side edges of the upper and lower sides, and sandwiching the three side edges of the composite film with the upper and lower heat seal bars while applying heat of about 210 ° C, Heat-seal polyethylene films. Thereby, a bag body in which the three side edges of 280 mm × 350 mm were heat-sealed was manufactured. This bag was placed in a vacuum drying oven, dried at 80 ° C. for 72 hours, and then glass wool made by Asahi Fiber Glass Co., Ltd. formed into a plate shape of 200 mm × 200 mm × 32 mm (fiber diameter 4 μm). After further drying at 169 ° C. for 36 minutes, the pressure was reduced to 1.0 × 10 ⁻³ Pa, and the opening at the other side edge of the bag was maintained with a 20 mm wide heat seal bar while maintaining the reduced pressure. A vacuum heat insulating material was manufactured by heat fusion at 210 ° C. In Comparative Example 2, as a heat seal bar, as described in the prior art document of the present specification, a plurality of rows of protrusions extending linearly continuously in the length direction are provided on the flat plate portion in the width direction. A heat seal bar was used.

[Evaluation method]
1. The thermal conductivity after the bags manufactured in thermal conductivity examples 1 to 3 and comparative examples 1 and 2 were treated at 105 ° C. for 200 hours was measured as the thermal conductivity measurement system Auto A HC-074A (manufactured by Eiko Seiki Co., Ltd.). Using a flat plate heat flow meter method and a two-sheet heat flow method, measurement was performed under the measurement conditions shown in Table 1 (measurement parallel conditions) and Table 2 (measurement temperature conditions). A thermal conductivity meter sandwiches a sample between upper and lower plates and measures the heat flux. In the thermal conductivity meter, the thermal conductivity is obtained by the following equation. The following sample thickness L is measured by sandwiching the sample between the upper and lower plates of the thermal conductivity meter.

λ = {(Qh + Qc) / 2} × L / ΔT
λ: Thermal conductivity Qh: High temperature side heat flow rate Qc: Low temperature side heat flow rate L: Sample thickness ΔT: Difference between high temperature side sample surface temperature (Th) and low temperature side sample surface temperature (Tc)

  Table 3 shows the measurement results. In Table 3, “◎” indicates that the thermal conductivity is 0.003 W / mK or less, and “◯” indicates that the thermal conductivity is greater than 0.01 W / mK and 0.05 W / mK, “X” indicates that the thermal conductivity is larger than 0.05 W / mK. From Table 3, Examples 1 to 3 according to the present invention have a thermal conductivity smaller than that of Comparative Example 1, and the thermal conductivity is equivalent to that of Comparative Example 2 cited in the prior art document of the present specification. It can be seen that the thermal conductivity is small. The vacuum heat insulating material is reduced in heat conduction by air due to the reduced pressure inside. Therefore, if the thermal conductivity is small as in the present invention, the amount of air entering the bag body through the heat seal region from the end face of the outer peripheral edge of the bag body is suppressed, and the bag body It can be seen that the sealing performance is maintained high. Therefore, it can be seen that excellent heat insulating performance can be realized as a vacuum heat insulating material.

2. Tensile strength of heat-sealed region The tensile strength of the heat-sealed region of the bag was measured by a measuring method based on JIS K-7127. As a sample piece, it cuts out from the heat sealing area | region of the outer peripheral edge part of a bag body inside by 15 mm in width and 150 mm in length, this sample piece is arrange | positioned perpendicularly, and as shown in FIG. The part extending over 20 mm in the length direction is fixed with a jig. Then, the sample piece was pulled with an autograph AGS-H manufactured by Shimadzu Corporation (test speed: 200 mm / min), and the load applied at the time of fracture was measured.

  Table 4 shows the measurement results. In Table 4, “◯” indicates a load at break of 60 N / 15 mm or more, “Δ” indicates a load at break of 40 N / 15 mm or more and less than 60 N / 15 mm, and “×” indicates a break. It is shown that the load is less than 40 N / 15 mm. From Table 4, it can be seen that Examples 1 to 3 according to the present invention have higher heat seal strength than Comparative Example 2 and are excellent in durability. Therefore, it can be seen that the vacuum heat insulating material can maintain excellent heat insulating performance over a long period of time.

DESCRIPTION OF SYMBOLS 1 Vacuum heat insulating material 2 Bag body 10 Core material 20 Composite film 22 Heat seal area | region 24 Heat-fusion layer 26 Recessed part 28 Row of recessed parts

Claims (7)

In a bag formed by stacking two composite films having a heat fusion layer so that the heat fusion layers face each other and heat-sealing at least a part of the outer peripheral edge,
The concave portion in which a plurality of concave portions in which the thickness of the heat-fusible layer is thinner than the periphery are arranged at intervals in the length direction of the thermal seal region on at least one surface of the heat seal region formed in the outer peripheral edge portion And a plurality of rows of the recesses are arranged at intervals in the width direction of the heat seal region,
Each of the rows of recesses is a bag that is disposed so that the recesses are positioned between two recesses of the row of recesses adjacent to each other.   2. The bag according to claim 1, wherein the row of recesses is provided on both surfaces of the heat seal region of the bag, and the positions of the recesses coincide on both surfaces of the heat seal region.   The bag according to claim 2, wherein the concave portion has the same shape as the concave portion provided to face the opposite surface of the heat seal region of the bag.   The concave portion has two heat seal bars having a flat plate portion and a plurality of protrusions protruding from the flat plate portion on one surface side and the other surface side of the bag body so that the positions of the protrusion portions coincide with each other. The bag according to claim 2 or 3, wherein the bag is formed by sandwiching the bag between the two heat seal bars and compressing the bag.   The bag according to any one of claims 1 to 4, wherein a shape of the concave portion is a quadrangular frustum shape whose outer shape gradually decreases toward the bottom surface.   The bag according to claim 5, wherein a corner between a side surface and a bottom surface of the recess is rounded.   The vacuum heat insulating material which carried out the pressure reduction sealing of the core material which has a fine space | gap as a filling in the bag body in any one of Claims 1-6.