Roof heat insulation structure

Abstract

To realize a roof heat insulation structure with excellent heat insulation performance and suppression of heat deformation of insulation materials at high temperatures.SOLUTION: In a roof heat insulation structure (10) for a wooden building, a heat insulation material (2) provided between adjacent rafters (1) includes a resin foam molded body, which contains a radiant heat transfer inhibitor and has a dimensional change rate of 1.0% or less before and after heating at 90°C for 48 hours.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a roof insulation structure. [Background technology]

[0002] The roof of a wooden building is required to have a thermal insulation performance to prevent the heat of the roof from being transmitted to the room. For example, Patent Document 1 discloses a roof insulation structure for a wooden building. The roof insulation structure described in Patent Document 1 is configured by filling a flat foamed resin insulation material between two rafters and laying a roof material on top of it. In addition, in the roof insulation structure of Patent Document 1, a long foamed resin insulation material is attached to the side part of the rafter as a support material against which the outer peripheral part of the flat foamed resin insulation material abuts. The width and thickness of the long foamed resin insulation material are thicker than the thickness of the flat foamed resin insulation material. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2004-036089 A Summary of the Invention [Problem to be solved by the invention]

[0004] In addition to thermal insulation performance, the roof of a wooden building is required to have a small dimensional change rate of the insulation material and suppress thermal deformation in the roof area that becomes hot due to solar radiation. The roof insulation structure described in Patent Document 1 has room for improvement in terms of suppressing thermal deformation of the insulation material under such high temperatures.

[0005] An object of one aspect of the present invention is to provide a roof insulation structure that is excellent in insulation performance and suppresses thermal deformation of the insulation material at high temperatures. [Means for solving the problem]

[0006] In order to solve the above problems, one aspect of the present invention is as follows.

[0007] [1] A roof insulation structure for a wooden building, comprising a plurality of rafters, an insulating material, and a roofing material, the insulating material being provided between or on adjacent rafters, the roofing material being laid on the upper side of the insulating material, the insulating material including a resin foam molding, the resin foam molding including a radiant heat transfer inhibitor, and having a dimensional change rate of 1.0% or less before and after heating at 90°C for 48 hours.

[0008] [2] The roof insulation structure of [1], wherein the radiation heat transfer inhibitor is at least one selected from the group consisting of graphite, carbon black, activated carbon, graphene, carbon nanotubes, coke, titanium oxide, aluminum, and copper, and the content of the radiation heat transfer inhibitor is 1 part by weight to 20 parts by weight per 100 parts by weight of the resin foam molding.

[0009] [3] The roof insulation structure according to [1] or [2], wherein the resin constituting the resin foam molding contains a styrene-based resin.

[0010] [4] The roof insulation structure according to [3], wherein the styrene-based resin has a structural unit derived from (meth)acrylic acid.

[0011] [5] The roof insulation structure according to any one of [1] to [4], wherein the resin foam molding is a foam bead molding.

[0012] [6] A roof insulation structure according to any one of [1] to [5], comprising one or more air passages, the air passages being arranged between the insulation material and the roof material and parallel to the rafters.

[0013] [7] The roof insulation structure of [6], wherein the air passage is a groove formed in the upper surface of the insulation material.

[0014] [8] A roof insulation structure as in [6], comprising a ventilation rafter, the ventilation rafter being provided on the upper side of the insulation material, and the air passage being formed by the roof material, the ventilation rafter, and the insulation material.

[0015] [9] A roof insulation structure according to any one of [1] to [8], wherein the insulation is provided between adjacent rafters, and an end of the insulation facing at least one of the two adjacent rafters has a slit, the slit extends parallel to the rafters and elastically deforms, and the insulation is elastically fitted tightly between the two adjacent rafters by the elastic force of the slit.

[0016]

[10] A roof insulation structure according to any one of [1] to [9], comprising a low emissivity layer on the upper surface side of the insulation material.

[0017]

[11] The roof insulation structure of

[10] , wherein the low emissivity layer contains at least one selected from the group consisting of aluminum, copper, nickel, and chromium. Effect of the Invention

[0018] According to one aspect of the present invention, a roof insulation structure having excellent insulation performance and suppression of thermal deformation of the insulation material at high temperatures can be realized. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a perspective view showing a schematic configuration of a roof insulation structure according to a first embodiment of the present invention. [Diagram 2] FIG. 1 is a cross-sectional view showing a schematic configuration of a roof insulation structure according to a first embodiment of the present invention. [Diagram 3] FIG. 2 is a partial cross-sectional view illustrating a fitting state of the insulation material to the rafters in the roof insulation structural body according to the first embodiment of the present invention. [Figure 4] FIG. 3 is a cross-sectional view showing a schematic configuration of a modified example of the roof insulation structure according to the first embodiment of the present invention. [Diagram 5] FIG. 4 is a cross-sectional view showing a schematic configuration of a roof insulation structure according to a second embodiment of the present invention. [Figure 6] FIG. 11 is a cross-sectional view showing a schematic configuration of a roof insulation structure according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] The following is a detailed description of the embodiments of the present invention. However, the present invention is not limited to these, and various modifications are possible within the scope of the description. The technical scope of the present invention also includes embodiments obtained by appropriately combining the technical means disclosed in the different embodiments and examples. In this specification, unless otherwise specified, "A to B" indicating a numerical range means "A or more (including A and larger than A) and B or less (including B and smaller than B)."

[0021] <Technical idea of ​​one embodiment of the present invention> In recent years, due to global warming and other factors, the roofs of wooden buildings have become extremely hot, at 70°C to 80°C, due to solar radiation. To cope with such high roof temperatures, roof insulation structures are required to have insulation performance that prevents the heat of the roof at 70°C to 80°C from being transmitted to the room. Furthermore, the insulation material applied to the roof insulation structure is required to have a small dimensional change rate at high temperatures of 70°C to 80°C and to suppress thermal deformation.

[0022] The present inventors have conducted extensive research into roof insulation structures that satisfy the above requirements, and have focused on insulation materials that can be applied to roof insulation structures. In roof insulation structures, it is necessary for the insulation material to (I) suppress an increase in thermal conductivity when the temperature rises, and (II) suppress dimensional changes at high temperatures. The inventors have found that a roof insulation structure that satisfies the above requirements can be realized by using an insulation material that contains a resin foam molded body containing a radiation heat transfer inhibitor and in which the dimensional change rate of the resin foam molded body before and after heating at 90°C for 48 hours is within a specific numerical range for the roof insulation structure, and have developed the roof insulation structure according to this embodiment.

[0023] In other words, the roof insulation structure of this embodiment is a roof insulation structure for a wooden building, and comprises a plurality of rafters, an insulating material, and a roofing material, the insulating material being provided between or on adjacent rafters, the roofing material being laid on the upper side of the insulating material, the insulating material including a resin foam molding, the resin foam molding containing a radiant heat transfer inhibitor, and having a dimensional change rate of 1.0% or less before and after heating at 90°C for 48 hours.

[0024] According to the roof insulation structure of this embodiment, the resin foam molded body contained in the insulation material contains a radiant heat transfer inhibitor and has a dimensional change rate of 1.0% or less before and after heating at 90°C for 48 hours, so that a roof insulation structure with excellent insulation performance and suppression of thermal deformation of the insulation material at high temperatures can be realized.

[0025] It has been known that a radiation heat transfer inhibitor is incorporated into a resin foam molded article. However, the fact that a resin foam molded article containing a radiation heat transfer inhibitor has the effect of suppressing an increase in thermal conductivity when the temperature rises, in addition to the effect of suppressing heat transfer due to radiation, was not known until now, and can be said to be a new discovery by the present inventors.

[0026] [Embodiment 1] Hereinafter, one embodiment of the present invention will be described in detail.

[0027] <Composition of roof insulation structure> Fig. 1 is a perspective view showing a schematic configuration of a roof insulation structure 10 according to the present embodiment. Fig. 2 is a cross-sectional view showing a schematic configuration of the roof insulation structure 10 according to the present embodiment.

[0028] In the drawings of the present application, "LD" refers to the length direction, "LDa" refers to one side in the length direction (front side), "LDb" refers to the other side in the length direction (rear side), "WD" refers to the width direction, "HD" refers to the height direction, "HDa" refers to the upper side which is one side in the height direction, and "HDb" refers to the lower side which is the other side in the height direction. The "length direction" here refers to one of the slope directions of the roof on which the roof insulation structure 10 is installed, and refers to the length direction of the rafters. The "width direction" refers to the direction perpendicular to the length direction in the slope direction of the roof, and refers to the width direction of the rafters.

[0029] In addition, the "height direction" is a direction perpendicular to both the "length direction" and the "width direction," and corresponds to a direction perpendicular to the slope of the roof. Therefore, in the specification and claims of this application, the upper side is a side determined according to the slope direction of the roof, and does not necessarily uniquely indicate only the upper side in the vertical direction.

[0030] As shown in FIG. 1 and FIG. 2, the roof insulation structure 10 includes a plurality of rafters 1, a heat insulating material 2, and a roof material 3. The rafters 1 are long members that constitute the roof frame of a wooden building, and are arranged so as to extend in the LD direction. The plurality of rafters 1 are arranged in parallel in the WD direction at a predetermined interval with respect to the wooden building. In the WD direction, the distance between two adjacent rafters 1 can be a distance that can be applied to conventionally known rafters. The distance between two adjacent rafters 1 may be narrowed when the roof material 3 is heavy, but in consideration of the labor hours and material costs, 200 mm to 600 mm is preferable, and 455 mm is generally applied. As the size (height x width) of the rafters 1, 45 mm x 45 mm, 60 mm x 45 mm, 75 mm x 45 mm, 75 mm x 60 mm, 90 mm x 60 mm, and 105 mm x 60 mm are appropriately adopted depending on the type of the roof material 3.

[0031] The heat insulating material 2 is a flat plate-like member and is provided between adjacent rafters 1. More specifically, the heat insulating material 2 is fitted between two adjacent rafters 1. The width of the heat insulating material 2 in the WD direction is approximately the same as the distance between the rafters 1 so that it can be fitted between two adjacent rafters 1. The width of the heat insulating material 2 in the WD direction can be a width that can be applied to a conventionally known roof insulation structure of a wooden building, and is 200 mm to 600 mm, and generally, it is preferably 455 mm. The length of the heat insulating material 2 in the LD direction can be a length that can be applied to a conventionally known roof insulation structure of a wooden building, and is generally 500 mm to 2000 mm, and preferably 700 mm to 1820 mm. The thickness of the heat insulating material 2 can be a thickness that can be applied to a conventionally known roof insulation structure of a wooden building, and is generally 30 mm to 200 mm, and preferably 45 mm to 105 mm.

[0032] The roofing material 3 is laid on the upper surface of the insulating material 2. Here, the embodiment "provided on the upper surface of the insulating material 2" includes an embodiment in which the roofing material 3 is provided on the insulating material 2 (provided in contact with the upper surface of the insulating material 2), an embodiment in which the roofing material 3 is provided above the insulating material 2 (provided at a distance from the upper surface of the insulating material 2), and an embodiment in which the roofing material 3 is laid on the upper surface of the insulating material 2 via another member.

[0033] The roofing material 3 comprises a roof underlayment 4 and a roof finishing material 5. The roof underlayment 4 comprises a plywood nailed to the insulating material 2 and a waterproof sheet laid on the plywood (not shown). The roof finishing material 5 is laid on the roof underlayment 4. The roof finishing material 5 includes at least one material selected from the group consisting of, for example, slate made of cement-based board material, rocks, etc.; steel plate made of galvalume, tin, copper, etc.; and roof tile made of clay, cement, concrete, etc.

[0034] In addition, the roof insulation structure 10 according to this embodiment is preferably provided with one or more air passages 9. The air passages 9 are preferably provided between the insulation material 2 and the roof material 3 so as to be parallel to the rafters 1. The air passages 9 are not provided locally in the roof insulation structure 10 but are provided throughout the entire structure. Moisture and condensation generated in the roof insulation structure 10 are discharged to the outside through the air passages 9. In this way, the air passages 9 improve the ventilation in the roof insulation structure 10, so that moisture and condensation inside the roof insulation structure 10 can be discharged to the outside without being retained, and corrosion of the components of the roof insulation structure 10 can be prevented.

[0035] In the roof insulation structure 10, the air passage 9 may be provided between the insulation material 2 and the roof material 3 so as to be parallel to the rafter 1, and the components constituting the air passage 9 are not limited. In the roof insulation structure 10 shown in Figs. 1 and 2, the air passage 9 is a groove 6 formed on the upper surface of the insulation material 2. The groove 6 is formed in each insulation material 2 and extends in the LD direction. The inlet and outlet of the groove 6 are connected to the outside of the roof insulation structure 10. Therefore, the outside air flows through the groove 6 in the roof insulation structure 10. In the roof insulation structure 10, moisture and condensation generated in the roof insulation structure 10 are discharged to the outside by the air flow flowing through the groove 6.

[0036] In order to improve the fit of the insulation material 2 between two adjacent rafters 1, both ends of the insulation material 2 facing the two adjacent rafters 1 have slits 7. The slits 7 extend parallel to the rafters 1 and are elastically deformable. That is, as shown in FIG. 2, the slits 7 are grooves formed at both ends of the insulation material 2 in the WD direction. The slits 7 extend in the LD direction. Furthermore, the slits 7 are elastically deformable so as to expand and contract in the WD direction.

[0037] In the roof insulation structure 10, the insulation material 2 is elastically fitted closely between two adjacent rafters 1 by the elastic force of the slits 7. Fig. 3 is a partial cross-sectional view for explaining the fitting state of the insulation material 2 to the rafters 1.

[0038] As shown in FIG. 3, the slits 7 allow the insulation material 2 to expand and contract in the WD direction. The insulation material 2 is fitted between the rafters 1 in a state where it is contracted in the WD direction. At this time, the slits 7 contract in a direction narrowing the width in the WD direction. The amount of contraction required for fitting the insulation material 2 to the rafters 1 is ensured by the slits 7. When the insulation material 2 is fitted between the rafters 1, a repulsive force (elastic force) against the above contraction is generated in the slits 7 of the insulation material 2. In addition, a frictional force is generated between the wall portion 2a on the rafter 1 side of the slits 7 and the rafter 1. The above repulsive force and the above frictional force allow the insulation material 2 to fit in a tight contact state without falling off the adjacent rafters 1.

[0039] The insulating material 2 is not limited to a configuration in which the slits 7 are formed at both ends in the WD direction. The insulating material 2 may be configured to have the slits 7 formed at one end in the WD direction, so long as the insulating material 2 can be fitted closely to the rafters 1 by the repulsive force and the frictional force. In other words, it is sufficient that at least one end of the insulating material 2 facing the two adjacent rafters 1 has the slits 7.

[0040] The shape of the slit 7 is not particularly limited as long as it can be fitted closely to the rafter 1 by the repulsive force and the frictional force. The slit 7 is preferably a V-shaped groove. The V-shaped groove is configured so that the width in the WD direction gradually narrows toward the inside of the thermal insulation material 2.

[0041] The width of the slit 7 is set so that when the insulating material 2 is fitted between the rafters 1, it has a repulsive force pressing against the rafters 1, which is necessary for a tight fit. For this reason, the dimension of the insulating material 2 in the WD direction is set to be larger than the dimension for fitting between the rafters 1 by the width of the slit 7. From the viewpoint of generating the above-mentioned repulsive force sufficiently, the depth of the slit 7 is preferably 50% to 70% of the thickness of the insulating material 2.

[0042] Moreover, the roof insulation structure 10 preferably includes a low emissivity layer 2b on the upper surface side of the insulation material 2. As shown in Fig. 2, the low emissivity layer 2b is formed on the upper surface of the insulation material 2. This low emissivity layer 2b blocks the transmission of radiant heat to the room, so that the insulation properties of the insulation material 2 can be sufficiently ensured.

[0043] The low emissivity layer 2b may be made of any material as long as it can block radiant heat. The low emissivity layer 2b preferably contains at least one selected from the group consisting of aluminum, copper, nickel, and chromium.

[0044] In addition, as long as the low emissivity layer 2b can block radiant heat, it is not limited to a configuration in which it is formed on the upper surface of the thermal insulation material 2. The low emissivity layer 2b only needs to be provided on the upper surface side of the thermal insulation material 2, and may be provided above the thermal insulation material 2 while being spaced apart from the thermal insulation material 2, for example.

[0045] The low emissivity layer 2b is provided appropriately for the roof insulation structure 10. Therefore, the roof insulation structure 10 does not necessarily have to include the low emissivity layer 2b.

[0046] <Modification> In the configuration of the roof insulation structure 10 according to the present embodiment, a modified example of the configuration shown in Figures 1 and 2 will be described. Figure 4 is a cross-sectional view showing a schematic configuration of a modified example of the roof insulation structure 10 according to the present embodiment.

[0047] As shown in Fig. 4, a modified roof insulation structure 10A has a roof material 3A having a different configuration from that shown in Fig. 1 and Fig. 2. In the roof insulation structure 10A, the roof material 3A includes a roof finishing material 5 and does not include a roof underlayment 4. In the roof insulation structure 10A, the roof finishing material 5 is laid on the rafters 1 and the insulation material 2.

[0048] <Radiation heat transfer inhibitor> In the roof insulation structure according to the present embodiment, the insulation material includes a resin foam molded body containing a radiation heat transfer inhibitor. This makes it possible to realize an insulation material that has high insulation properties and can suppress an increase in thermal conductivity when the temperature rises. As a result, by providing the insulation material as a component of the roof insulation structure, the insulation performance of the roof insulation structure is improved.

[0049] The term "radiation heat transfer inhibitor" as used herein refers to a substance that has the property of reflecting, scattering, or absorbing light in the near infrared or infrared region. Examples of the radiation heat transfer inhibitor include carbon materials such as graphite, graphene, carbon black, carbon nanotubes, activated carbon, expanded graphite, and coke; aluminum-based compounds such as aluminum oxide and aluminum chloride; titanium-based compounds such as titanium dioxide and titanium tetrachloride; metal sulfates such as calcium sulfate and magnesium sulfate; antimony-based compounds such as diantimony trioxide and antimony trifluoride; heat ray reflectors such as metal oxides; heat ray absorbers such as phthalocyanine and tin-doped indium oxide; and metal particles such as copper.

[0050] Among these, the radiation heat transfer inhibitor is preferably at least one selected from the group consisting of graphite, carbon black, activated carbon, graphene, carbon nanotubes, coke, titanium oxide, aluminum, and copper. Furthermore, in view of the high radiation heat transfer inhibitory effect relative to cost, the radiation heat transfer inhibitor is preferably at least one of graphite and carbon black. Note that the radiation heat transfer inhibitor may be one of the compounds exemplified above, either singly or in combination of two or more.

[0051] Examples of graphite include flake graphite, amorphous graphite, spherical graphite, and artificial graphite, and among these, flake graphite is preferred because it exhibits a high radiation suppression effect. In this specification, the term "flake" also includes scaly, thin, and plate-like graphite.

[0052] The average particle size of the graphite is preferably from 1 μm to 10 μm, more preferably from 2.5 μm to 9 μm, further preferably from 3.0 μm to 6.0 μm, and most preferably from 4.0 μm to 6.0 μm.

[0053] In this specification, the average particle size of the radiation heat transfer inhibitor is defined as follows: The particle size distribution is measured and analyzed by a laser diffraction scattering method based on the Mie theory in accordance with ISO13320:2009 and JIS Z8825-1, and the particle size at which the cumulative volume of the total particles is 50% (volume average particle size by the laser diffraction scattering method) is defined as the average particle size.

[0054] The larger the average particle diameter of graphite, the lower the manufacturing cost. In particular, graphite with an average particle diameter of 1 μm or more is very inexpensive and can reduce costs because the manufacturing cost, including the cost of crushing, is low. Furthermore, when the average particle diameter of graphite is 1 μm or more, it is possible to manufacture a styrene-based resin foamed molded product with good thermal insulation properties. When the average particle diameter of graphite is 10 μm or less, the cell membrane is less likely to break when producing pre-expanded particles and a styrene-based resin foamed molded product from the expandable styrene-based resin particles, which has the effects of facilitating high expansion, increasing ease of molding, and increasing the compressive strength of the styrene-based resin foamed molded product.

[0055] If the average particle size of the graphite is 3.0 μm or more, a molded product having a lower thermal conductivity and therefore a higher thermal insulation can be obtained. If the average particle size of the graphite is 6.0 μm or less, a molded product having excellent surface beauty, a lower thermal conductivity and therefore a higher thermal insulation can be obtained.

[0056] The carbon black is not particularly limited, and coloring carbon black, conductive carbon black, etc. can be used.

[0057] <Dimensional change rate of resin foam molded body> In the roof insulation structure according to the present embodiment, the resin foam molded product contained in the insulation material has a dimensional change rate before and after heating at 90°C for 48 hours of 1.0% or less, more preferably 0.9% or less, further preferably 0.8% or less, 0.7% or less, 0.6% or less, 0.5% or less, 0.4% or less, 0.3% or less, 0.2% or less, 0.1% or less, or 0%.

[0058] Here, in the actual use of the roof insulation structure 10, there is a time cycle (1 day) of (1) a rise in material temperature due to solar radiation, (2) heat storage, and (3) a drop in material temperature due to heat radiation, for the change in material temperature of the roof insulation structure 10. Taking this time cycle into consideration, the roof insulation structure 10 is exposed to a high temperature range of 70°C to 80°C due to sunlight, especially during the day. In consideration of such actual use, the insulation material of the roof insulation structure 10 is required to have small dimensional change in the temperature history under the conditions of a heating temperature of 90°C and a heating time of at least 24 hours per day (24 hours or more). Therefore, even if it is subjected to a thermal history under the heating conditions of 90°C and 48 hours, the dimensional stability of the resin foam molded body is very high if the dimensional change rate before and after heating is within the above numerical range. Therefore, according to the above configuration, the resin foam molded body is used as the insulation material constituting the roof insulation structure 10, so that dimensional change can be stably and sufficiently suppressed.

[0059] <Resin foam molding> In the present embodiment, the resin foam molded product is not particularly limited, but examples thereof include thermosetting resin foam molded products such as urethane foam, phenol foam, and melamine foam; rubber foam molded products such as nitrile rubber; (a) styrene-based resins such as polystyrene (PS), styrene-acrylonitrile copolymer (AS), styrene-(meth)acrylic acid copolymer (heat-resistant PS), styrene-(meth)acrylic acid ester copolymer, styrene-butadiene copolymer (HIPS), N-phenylmaleimide-styrene-maleic anhydride terpolymer, and alloys thereof with AS (IP); (b) vinyl-based resins such as polymethyl methacrylate, polyacrylonitrile-based resins, and vinyl chloride-based resins; (c) polypropylene, polyethylene, ethylene-propylene copolymer, ethylene-propylene-butene terpolymer, cycloolefin copolymer ... Examples of the resins include polyolefin resins such as fin-based (co)polymers, and polyolefin resins in which branched structures and crosslinked structures are introduced to control the rheology, (d) polyamide resins such as nylon 6, nylon 66, nylon 11, nylon 12, and MXD nylon, (e) polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyarylate, and polycarbonate, (f) aliphatic polyester resins such as polylactic acid, and (g) engineering plastics such as polyphenylene ether resins (PPE), modified polyphenylene ether resins (modified PPE), polyoxymethylene resins, polyphenylene sulfide resins, polyphenylene sulfide resins, aromatic polyether resins, and polyether ether ketone resins. The resins constituting these resin foams may be used alone or in combination of two or more. Among these resin foam molded products, resin foam molded products made of styrene-based resin or modified polyphenylene ether-based resin (modified PPE) are preferred because they are inexpensive and easy to foam mold.

[0060] The styrene-based resin may be not only a styrene homopolymer (polystyrene homopolymer) but also a copolymer in which (a) styrene and (b) another monomer copolymerizable with styrene or a derivative thereof (hereinafter simply referred to as "the other monomer or a derivative thereof") are copolymerized, as long as the effect of this embodiment is not impaired.

[0061] Examples of the "other monomers or derivatives thereof" include: (a) styrene derivatives such as methylstyrene, dimethylstyrene, ethylstyrene, diethylstyrene, isopropylstyrene, bromostyrene, dibromostyrene, tribromostyrene, chlorostyrene, dichlorostyrene, and trichlorostyrene; (b) polyfunctional vinyl compounds such as divinylbenzene; (c) (meth)acrylic acid compounds such as acrylic acid and methacrylic acid; (d) methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, and the like. Examples of such compounds include (meth)acrylic acid ester compounds such as butyl methacrylate, (e) vinyl cyanide compounds such as (meth)acrylonitrile, (f) diene compounds or derivatives thereof such as butadiene, (g) unsaturated carboxylic acid anhydrides such as maleic anhydride and itaconic anhydride, and N-alkyl-substituted maleimide compounds such as N-methylmaleimide, N-butylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N-(2)-chlorophenylmaleimide, N-(4)-bromophenylmaleimide, and N-(1)-naphthylmaleimide. These compounds may be used alone or in combination of two or more.

[0062] The styrene-based resin used in the present embodiment is not limited to a styrene homopolymer and / or a copolymer of styrene and another monomer or a derivative thereof, and may be a blend of (a) a styrene homopolymer and / or a copolymer of styrene and another monomer or a derivative thereof and (b) a homopolymer of the other monomer or derivative described above, or a copolymer thereof, as long as the effect of the present embodiment is not impaired.

[0063] In a preferred embodiment, the resin constituting the resin foamed molded product includes a styrene-based resin. ( However, the styrene-based resin does not include 100% styrene homopolymer). More specifically, the resin contains a styrene-based resin as a main component. Furthermore, the styrene-based resin more preferably has a constitutional unit derived from (meth)acrylic acid. This can suppress the dimensional change of the heat insulating material in a high temperature environment (90°C). The styrene-based resin is preferably a styrene-(meth)acrylic acid copolymer (heat-resistant PS). In particular, since the temperature of the roof of a wooden building is often in the range of 70°C to 80°C due to solar radiation, the use of a styrene-based resin having a constitutional unit derived from (meth)acrylic acid can suppress the deformation of the resin foam molded body in the above temperature range. As shown in the examples described later, when the styrene-based resin is 100% styrene homopolymer and contains a radiation heat transfer inhibitor, the resin foam molded body shrinks significantly and deformation in the above temperature range is not suppressed.

[0064] In the above preferred embodiment, the content of the constitutional unit (monomer unit) derived from (meth)acrylic acid is preferably 3.0% by weight to 30% by weight, more preferably 5.0% by weight to 25% by weight, in order to suppress deformation of the resin foam molded article, where the total amount of the styrene-based resin is taken as 100% by weight.

[0065] In the above preferred embodiment, the styrene resin is not limited to a styrene resin having a structural unit derived from (meth)acrylic acid, and may be any styrene resin other than 100% styrene homopolymer. Examples of the styrene resin include an alloy of styrene homopolymer / diene rubber reinforced polystyrene and polyphenylene ether resin.

[0066] In the above preferred embodiment, in order to suppress deformation of the resin foam molded article, the glass transition temperature (Tg) of the resin constituting the resin foam molded article is preferably 105°C to 135°C, and more preferably 110°C to 130°C.

[0067] In addition, as a resin foam molded product that can meet the needs of a recycling society, a foam molded product of a thermoplastic resin, such as the above-mentioned styrene-based resin foam, which can be recycled, is more preferable. In addition, if the base resin is a styrene-based resin, polystyrene foam used as a fish box or a cushioning material for home appliances can be recycled again and used as a raw material for constituting the resin foam molded product in the roof insulation structure according to this embodiment. Such an effect also contributes to the achievement of, for example, Goal 12 of the Sustainable Development Goals (SDGs) proposed by the United Nations, "Ensure sustainable consumption and production patterns."

[0068] Furthermore, from the viewpoint of producing the insulating material for the roof insulation structure at low cost, the resin foam molded product is preferably an in-mold foam molded product.

[0069] Furthermore, from the viewpoint of productivity of the resin foamed molded product, the resin foamed molded product is preferably a foamed bead molded product. The foamed bead molded product is a molded product obtained by filling a molding die with foamed beads and hot molding it, and is widely used for applications such as fish boxes, cushioning materials, and automobile bumpers. The foamed bead molded product is preferably obtained by hot molding pre-foamed beads described later.

[0070] <Amount of radiation heat transfer inhibitor added> In this embodiment, the content of the radiation heat transfer inhibitor is preferably 1 part by weight to 20 parts by weight per 100 parts by weight of the resin foam molded product, from the viewpoint of a balance between the ease of foam molding and the effect of reducing thermal conductivity. When the content of the radiation heat transfer inhibitor is 1 part by weight or more, the effect of reducing thermal conductivity tends to be sufficient, while when the content is 20 parts by weight or less, the cell membrane is less likely to break when producing a foam molded product from the expandable thermoplastic resin particles, so that high foaming is easy and the control of the expansion ratio tends to be easy.

[0071] More preferably, the content of the radiation heat transfer inhibitor is 3.0 parts by weight to 10 parts by weight per 100 parts by weight of the resin foam molded product. When the content of the radiation heat transfer inhibitor is 3.0 parts by weight or more, the thermal conductivity of the obtained resin foam molded product is low, so that higher heat insulation properties can be obtained even in high temperature environments, and thus good heat insulation performance of the roof insulation structure can be obtained. In addition, when the content of the radiation heat transfer inhibitor is 10 parts by weight or less, the foaming and moldability of the base resin is not adversely affected, and the surface beauty of the obtained foam molded product is good.

[0072] <Styrene resin foam molded body> Next, as the resin foam molded article, a styrene-based resin foam molded article containing a styrene-based resin as a constituent resin will be described in more detail.

[0073] (foaming agent) In producing a styrene-based resin foamed molded article, a foamable styrene-based resin composition may be prepared by further adding a foaming agent. The foamable styrene-based resin composition may be used to produce the foamable styrene-based resin particles described below, or to mold the resin foamed molded article. The foaming agent is not particularly limited, but from the viewpoint of a good balance between foamability and product life, and easy high expansion ratio when actually used, a hydrocarbon having 3 to 6 carbon atoms is preferable, and a hydrocarbon having 4 to 5 carbon atoms is more preferable. The reason why the number of carbon atoms is set to 3 or more is that the foaming agent has low volatility, so that the foaming agent is less likely to escape from the resulting foamable styrene-based resin particles. As a result, when the foamable styrene-based resin particles are actually used in the foaming process, the foaming agent remains sufficiently in the foamable styrene-based resin particles, making it possible to obtain sufficient foaming power, and making it easy to increase the expansion ratio. In addition, the reason why the number of carbon atoms is set to 6 or less is that the boiling point of the foaming agent is not too high, so that sufficient foaming power can be easily obtained by heating during pre-foaming, and there is a tendency that high expansion is easy. Examples of the hydrocarbon having 3 to 6 carbon atoms include propane, normal butane, isobutane, normal pentane, isopentane, neopentane, cyclopentane, normal hexane, and cyclohexane. These may be used alone or in combination of two or more. Other blowing agents that may be used in the present embodiment include hydrofluoroolefins, hydrochlorofluoroolefins, and hydrofluorocarbons.

[0074] The amount of the foaming agent is preferably 4.0 to 10 parts by weight relative to 100 parts by weight of the styrene-based resin composition. This provides an effect that the resulting expandable styrene-based resin particles have a better balance between the expansion speed and the expansion power, and are more stable and easier to expand. Specifically, the amount of the foaming agent is set to 4.0 parts by weight or more because the expansion power required for expansion is sufficient, which makes it easy to expand to a high expansion ratio, and tends to make it easier to manufacture a styrene-based resin foam molded body having the strength required for the heat insulating material according to this embodiment with an expansion ratio of about 30 to 50 times. The amount of the foaming agent is set to 10 parts by weight or less because the flame retardant performance is good and the manufacturing time (molding cycle) when manufacturing a styrene-based resin foam molded body is shortened, which tends to reduce the manufacturing cost. The amount of the foaming agent is more preferably 4.5 to 9.0 parts by weight, and even more preferably 5.0 to 8.5 parts by weight, relative to 100 parts by weight of the styrene-based resin composition.

[0075] (Flame retardant) The styrene-based resin composition may contain a flame retardant. The flame retardant is not particularly limited, and any flame retardant that has been used in the past for styrene-based resin foam moldings may be used. Among them, it is preferable to use a bromine-based flame retardant that has a high flame retardancy-imparting effect. Examples of the brominated flame retardant include brominated bisphenol compounds such as 2,2-bis[4-(2,3-dibromo-2-methylpropoxy)-3,5-dibromophenyl]propane (also known as tetrabromobisphenol A-bis(2,3-dibromo-2-methylpropyl ether)) and 2,2-bis[4-(2,3-dibromopropoxy)-3,5-dibromophenyl]propane (also known as tetrabromobisphenol A-bis(2,3-dibromopropyl ether)); brominated butadiene-vinyl aromatic hydrocarbon copolymers such as tetrabromocyclooctane, tris(2,3-dibromopropyl)isocyanurate, brominated styrene-butadiene block copolymers, brominated random styrene-butadiene copolymers, and brominated styrene-butadiene graft copolymers (for example, those disclosed in JP2009-516019A). These brominated flame retardants may be used alone or in combination of two or more.

[0076] The bromine-based flame retardant is preferably 0.8% by weight or more, and more preferably 5.0% by weight or less, of 100% by weight of the styrene-based resin composition, because it is easy to control the expansion ratio to the desired value and because of the balance of flame retardancy when the radiation heat transfer inhibitor is added. If the bromine content is 0.8% by weight or more, the flame retardancy effect tends to be large, and if it is 5.0% by weight or less, the strength of the resulting styrene-based resin foam molding tends to increase. In a more preferred embodiment, the bromine-based flame retardant is blended into the styrene-based resin composition or the expandable styrene-based resin particles so that the bromine content is 1.0 to 3.5% by weight.

[0077] (Heat stabilizer) In the production of styrene-based resin foam molded articles, the deterioration of flame retardancy and degradation of the styrene-based resin due to decomposition of the bromine-based flame retardant during the production process can be suppressed by further using a heat stabilizer in combination. The heat stabilizer can be used in appropriate combination depending on the type of styrene-based resin used, the type and content of the foaming agent, the type and content of the carbon, the type and content of the flame retardant, etc.

[0078] As the heat stabilizer, a hindered amine compound, a phosphorus-based compound, a phenol-based stabilizer, or an epoxy compound is preferred because the weight loss temperature in the thermogravimetric analysis of the mixture containing a bromine-based flame retardant can be arbitrarily controlled. The heat stabilizer can be used alone or in combination of two or more. These heat stabilizers can also be used as light resistance stabilizers as described below.

[0079] (Radical generator) When producing a styrene-based resin foam molded article, a radical generator is further contained in the styrene-based resin composition, and high flame retardant performance can be achieved by using the radical generator in combination with a bromine-based flame retardant.

[0080] The radical generators can be used in appropriate combination depending on the type of styrene-based resin, the type and content of foaming agent, the type and content of radiation heat transfer inhibitor, and the type and content of bromine-based flame retardant used.

[0081] Examples of the radical generator include cumene hydroperoxide, dicumyl peroxide, t-butyl hydroperoxide, 2,3-dimethyl-2,3-diphenylbutane, poly-1,4-isopropylbenzene, etc. The radical generators can be used alone or in combination of two or more.

[0082] (Other additives) The styrene-based resin composition may contain, as necessary, one or more additives selected from the group consisting of processing aids, light resistance stabilizers, nucleating agents, foaming aids, antistatic agents, and colorants such as pigments, within the scope of not impairing the above-mentioned effects.

[0083] Examples of the processing aid include sodium stearate, magnesium stearate, calcium stearate, zinc stearate, barium stearate, and liquid paraffin.

[0084] Examples of the light resistance stabilizer include the above-mentioned hindered amines, phosphorus-based stabilizers, and epoxy compounds, as well as phenol-based antioxidants, nitrogen-based stabilizers, sulfur-based stabilizers, and benzotriazoles.

[0085] Examples of nucleating agents include inorganic compounds such as silica, calcium silicate, wollastonite, kaolin, clay, mica, zinc oxide, calcium carbonate, sodium hydrogen carbonate, and talc; polymeric compounds such as methyl methacrylate copolymers and ethylene-vinyl acetate copolymer resins; olefin waxes such as polyethylene wax; and fatty acid bisamides such as methylene bisstearyl amide, ethylene bisstearyl amide, hexamethylene bispalmitic amide, and ethylene bisoleic amide.

[0086] The foaming assistant is preferably a solvent having a boiling point of 200° C. or less under atmospheric pressure, and examples thereof include aromatic hydrocarbons such as styrene, toluene, ethylbenzene, and xylene; alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; and acetates such as ethyl acetate and butyl acetate.

[0087] The antistatic agent and colorant may be any of those conventionally used in resin compositions.

[0088] These other additives may be used alone or in combination of two or more.

[0089] <Method of producing expandable styrene-based resin particles> Next, a method for producing the expandable styrene resin particles used for producing the styrene resin foamed molded article will be described. The following two methods (A) and (B) can be mentioned as the production method.

[0090] (A) A styrene resin, a radiation heat transfer inhibitor, and additives such as a flame retardant, a radical generator, and a stabilizer, if necessary, are melt-kneaded in an extruder, and the melt of the styrene resin composition is extruded through a die having small holes, and then cut with a cutter to granulate the composition, thereby obtaining styrene resin particles. The styrene resin particles are then suspended in water, and a blowing agent is supplied to incorporate the blowing agent into the styrene resin particles, thereby obtaining expandable styrene resin particles. In the method (A), the granulation with a cutter may be a cold cut method or a hot cut method.

[0091] (B) A styrene resin, a radiation heat transfer inhibitor, and, if necessary, additives such as a flame retardant, a radical generator, and a stabilizer are fed to an extruder and melt-kneaded to obtain a resin composition (I). A foaming agent is dissolved and dispersed in the resin composition (I) by the extruder or a dispersing device downstream of the extruder to obtain a molten foaming agent-containing styrene resin composition. The resulting molten material is extruded through a die having many small holes attached downstream of the extruder into a cutter chamber filled with pressurized circulating water. Then, immediately after extrusion, the molten material is cut by a rotating cutter in contact with the die and cooled and solidified by pressurized circulating water to obtain expandable styrene resin particles.

[0092] In the above method (B), in view of simplicity of equipment, it is preferable to directly inject the foaming agent under pressure into an extruder which supplies and melt-kneads the styrene-based resin, the radiation heat transfer inhibitor, and additives such as a flame retardant, a radical generator, and a stabilizer, and to dissolve and disperse the foaming agent in the resin to obtain a molten foaming-agent-containing styrene-based resin composition.

[0093] (Granulation conditions) The granulation conditions for the expandable styrene-based resin particles in the production methods (A) and (B) will be described.

[0094] First, the die used for granulation is not particularly limited, but may be, for example, one having small holes with a diameter of 0.3 mm to 2.0 mm, preferably 0.4 mm to 1.0 mm.

[0095] In the above manufacturing method (B), the temperature of the molten material immediately before being extruded through the die is preferably Tg+40° C. or higher, more preferably Tg+40° C. to Tg+110° C., and even more preferably Tg+60° C. to Tg+90° C., where Tg is the glass transition temperature of the resin in a state in which no foaming agent is contained. In the case of a styrene homopolymer, since Tg is about 100° C., a preferred temperature range is 140 to 210° C., and a more preferred range is 160 to 190° C.

[0096] In the above-mentioned (B) manufacturing method, if the temperature of the molten resin immediately before being extruded through the die is Tg+40°C or higher, the viscosity of the extruded molten material is low, the clogging of the small holes is unlikely to occur, and the actual opening rate of the small holes is not reduced, so that the shape of the obtained expandable styrene-based resin particles can be prevented from becoming distorted or irregular. On the other hand, if the temperature of the extruded molten material immediately before being extruded through the die is Tg+110°C or lower, the extruded molten material is likely to solidify, is unlikely to wrap around the rotary cutter, and can be cut stably.

[0097] In the above-mentioned (B) production method, the cutting device for cutting the molten material extruded into the pressurized circulating water for cooling is not particularly limited, but examples thereof include a device in which the molten material is cut into small pellets by a rotary cutter that comes into contact with a die, and the expandable styrene-based resin particles are transported to a centrifugal dehydrator in the pressurized circulating water without being expanded, and are dehydrated and aggregated.

[0098] The conditions of the pressurized circulating water can be appropriately set according to the type and content of the styrene resin, additive, foaming agent, and radiation heat transfer inhibitor used, but the conditions are preferably such that foaming of the molten material extruded from the die is suppressed and the material is stably cut by the cutter. Specifically, the temperature condition of the pressurized circulating water is preferably 45°C to 90°C, more preferably 50 to 85°C. As for the pressure condition, the true density of the obtained expandable styrene resin particles is preferably 950 kg / m 3 ~1,050kg / m 3 , more preferably 1,000 to 1,050 kg / m 3Although it depends on the type of blowing agent used, when butane or pentane is used as the blowing agent, the pressure condition is preferably 0.6 to 2.0 MPa, more preferably 0.7 to 1.7 MPa, and further preferably 0.8 to 1.5 MPa.

[0099] In the method for producing expandable styrene-based resin particles, the conditions for impregnation of the blowing agent in the above-mentioned production method (A) may be the same as those generally used, and may be appropriately set.

[0100] <Pre-expanded particles and resin foam molded body> The pre-expanded thermoplastic resin particles used in the heat insulating material according to the present embodiment are obtained by pre-expanding (primary expansion) thermoplastic resin particles containing a foaming agent (sometimes referred to as expandable thermoplastic resin particles). Examples of the expandable thermoplastic resin particles include the above-mentioned expandable styrene-based resin particles.

[0101] Since the pre-expanded particles are obtained as described above, the shrinkage immediately after pre-expanding is reduced. Therefore, the pre-expanded particles have a high expansion ratio, and the resin foam molded body obtained by secondary expanding and molding the pre-expanded particles has a high expansion ratio, i.e., is lightweight. In addition, the pre-expanded particles have a radiation heat transfer inhibitor. Therefore, the resin foam molded body obtained from the pre-expanded particles has a low thermal conductivity. That is, the pre-expanded particles can provide a resin foam molded body having a low thermal conductivity, in other words, a high thermal insulation.

[0102] The expandable thermoplastic resin particles are expanded 10 to 110 times by a conventional pre-expanding process, for example, by heated steam to obtain pre-expanded particles, which are then cured for a certain period of time as necessary before being used for molding. The obtained pre-expanded particles are molded (for example, molded in a mold) by steam using a conventional molding machine to produce a resin foam molded article. Depending on the shape of the mold used, a molded article in a complex shape and a block-shaped molded article can be obtained.

[0103] <Thermal conductivity of resin foam molded bodies> The thermal conductivity of the resin foam molded body used in the heat insulating material according to this embodiment will be described below. The thermal conductivity of the resin foam molded body preferably satisfies the following.

[0104] That is, the resin foam molded product preferably has a ratio of thermal conductivity (λ1) measured at an average temperature of 20° C. to thermal conductivity (λ2) measured at an average temperature of 40° C. that satisfies the following formula. λ2 / λ1<1.08.

[0105] The above "thermal conductivity (λ1) measured at an average temperature of 20°C" refers to the thermal conductivity at a center temperature of 20°C, measured in accordance with JIS A9511:2006R for a resin foam molded body after it has been left to stand at a temperature of 60°C for 48 hours and then at a temperature of 23°C for 24 hours. The thermal conductivity at a center temperature of 20°C refers to the thermal conductivity in the low temperature range in which plate temperatures are set to 10°C and 30°C (average temperature 20°C, temperature difference 20°C) using a heat flow meter method in accordance with JIS A1412-2:1999.

[0106] The above-mentioned "thermal conductivity (λ2) measured at an average temperature of 40°C" refers to the thermal conductivity at a center temperature of 40°C measured in accordance with JIS A9511:2006R for a resin foam molded body after it has been left to stand at 60°C for 48 hours and then at 23°C for 24 hours. The thermal conductivity at a center temperature of 40°C refers to the thermal conductivity in the high temperature range in which plate temperatures are set to 10°C and 70°C (average temperature 40°C, temperature difference 60°C) using a heat flow meter method in accordance with JIS A1412-2:1999.

[0107] According to this embodiment, the ratio λ2 / λ1 of the thermal conductivity (λ1) measured at an average temperature of 20°C to the thermal conductivity (λ2) measured at an average temperature of 40°C is less than 1.08, so the resin foam molded product has small temperature dependency of thermal conductivity and can maintain heat insulating performance in high temperature ranges. If λ2 / λ1 is 1.08 or more, the temperature dependency of thermal conductivity becomes large, and it tends to be difficult to maintain heat insulating performance in high temperature ranges. λ2 / λ1 is more preferably 1.05 or less.

[0108] The thermal conductivity (λ1) is preferably 0.0300 W / mK or less, and more preferably 0.0295 W / mK or less. If the thermal conductivity (λ1) is within the above range, a resin foam molded product that maintains a very low thermal conductivity and therefore high thermal insulation for a long period of time can be obtained.

[0109] The thermal conductivity (λ2) is preferably 0.0324 W / mK or less, and more preferably 0.0308 W / mK or less. If the thermal conductivity (λ2) is within the above range, the effect of maintaining the heat insulating performance in the high temperature range is achieved.

[0110] Furthermore, the higher the expansion ratio of the resin foam molded article, the less the amount of expandable thermoplastic resin particles used as the raw material. Therefore, according to this embodiment, a resin foam molded article with a high expansion ratio can be produced at low cost.

[0111] Specifically, the resin foam molded body used in the heat insulating material according to this embodiment has an expansion ratio of 30 times (cm 3 The expansion ratio of the resin foamed molded article is preferably 40 times (cm / g) or more. 3 / g) or more, and more preferably 50 times (cm 3 According to this configuration, even when the resin foam molded article is 30 times or more expanded, a low thermal conductivity can be achieved, so that even a resin foam molded article with a higher expansion ratio, which is advantageous in terms of low production cost and light weight, can exhibit high-performance heat insulation properties.

[0112] In this specification, the expansion ratio is expressed as "times" or "cm 3 / g", but these have the same meaning.

[0113] The average cell diameter of the resin foam molded product is preferably 70 to 500 μm, more preferably 70 to 250 μm, even more preferably 90 to 200 μm, and even more preferably 100 to 180 μm. When the average cell diameter is within the above numerical range, the resin foam molded product has high heat insulating properties. If the average cell diameter is 70 μm or more, the closed cell ratio of the foam molded product increases, and if the average cell diameter is 500 μm or less, the thermal conductivity decreases. The average cell diameter can be adjusted, for example, by appropriately selecting the amount of nucleating agent.

[0114] In addition, the resin foam molded product has low thermal conductivity, self-extinguishing properties, and can be adjusted to have an oxygen index of at least 26. Such a resin foam molded product can be suitably used as a thermal insulation material for the roof insulation structure according to this embodiment.

[0115] The resin foam molded product is preferably a thermoplastic resin foam molded product obtained by molding pre-expanded particles of the thermoplastic resin. This allows the thermoplastic resin foam molded product to have a high expansion ratio, i.e., to be lightweight. In addition, the thermoplastic resin foam molded product has low thermal conductivity, i.e., high heat insulation.

[0116] [Embodiment 2] Other embodiments of the present invention will be described below. For ease of explanation, the same reference numerals are given to components having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

[0117] Fig. 5 is a cross-sectional view showing a schematic configuration of a roof insulation structure 10B according to this embodiment. As shown in Fig. 5, the roof insulation structure 10B differs from the roof insulation structure 10 according to the first embodiment in that it includes a ventilation rafter 8 and in the configuration of the insulation material 2B.

[0118] In the roof insulation structure 10B, no recessed groove 6 is formed on the upper surface of the insulation material 2B. The upper surface of the insulation material 2B is approximately parallel to the lower surface of the roof underlayment 4 of the roof material 3.

[0119] The ventilation rafter 8 is a member for forming an air passage 9 between the insulating material 2B and the roofing material 3. The ventilation rafter 8 is provided on the upper surface side of the insulating material 2B. In the roof insulation structure 10B, the air passage 9 is formed by the roofing material 3, the ventilation rafter 8, and the insulating material 2B.

[0120] More specifically, the ventilation rafter 8 is a member interposed between the upper surfaces of the rafters 1 and the insulating material 2B and the lower surface of the roof material 3. In the roof insulation structure 10B, the ventilation rafter 8 is a long rod-shaped member extending in the LD direction, and is provided on the upper surface of each rafter 1. The ventilation rafter 8 ensures a space between the insulating material 2B and the roof material 3, so that an air passage 9 can be formed. The ventilation rafter 8 acts as a spacer that ensures a space between the insulating material 2B and the roof material 3.

[0121] [Embodiment 3] Further, for the sake of convenience, the same reference numerals are given to the members having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

[0122] 6 is a cross-sectional view showing a schematic configuration of a roof insulation structure 10C according to this embodiment. As shown in FIG. 6, the roof insulation structure 10C differs from the roof insulation structure 10B according to the second embodiment in the configuration of the insulation material 2C.

[0123] 6, the heat insulating material 2C is provided on adjacent rafters 1, but not between adjacent rafters 1. In this way, the heat insulating material 2C is not configured to be fitted between adjacent rafters 1, and therefore does not have a slit 7.

[0124] In the roof insulation structure 10C, the lower surface of one insulation material 2C is in contact with the upper surfaces of at least two rafters 1. The insulation material 2C does not contact the side surfaces of the rafters 1 in the WD direction.

[0125] In the roof insulation structure 10C, the ventilation rafter 8 is provided on the upper surface of the insulation material 2C. In the WD direction, the ventilation rafter 8 is disposed at approximately the same position as the rafter 1. The ventilation passage 9 is formed by the roof material 3, the ventilation rafter 8, and the insulation material 2C.

[0126] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. EXAMPLES

[0127] Examples, comparative examples and reference examples are given below, but the present invention is not limited to these.

[0128] The measurement and evaluation methods in the following Examples, Comparative Examples and Reference Examples are as follows.

[0129] (Measurement of thermal conductivity of styrene-based resin foam molded bodies) A sample measuring 300 mm in length, 300 mm in width, and 25 mm in thickness was cut out from the styrene-based resin foam molded body. The sample was left to stand at 60° C. for 48 hours and then at 23° C. for 24 hours. Then, the thermal conductivity (λ1) in the low temperature range was measured using a thermal conductivity measuring device (HC-074, manufactured by Eiko Seiki Co., Ltd.) in accordance with JIS A1412-2:1999 by the heat flow meter method with plate temperatures set to 10° C. and 30° C. (average temperature 20° C., temperature difference 20° C.).

[0130] On the other hand, in order to evaluate the insulating properties at high temperatures as an insulating material for roof insulation panels, assuming a high temperature environment in which the insulating material is exposed to high temperatures, the plate temperatures were set to 10°C and 70°C (average temperature 40°C, temperature difference 60°C) and the thermal conductivity (λ2) in the high temperature range was measured.

[0131] (Measurement of foaming ratio) A sample of 300 mm in length × 300 mm in width × 25 mm in thickness was cut out from the styrene-based resin foam molded body in the same manner as described above (Measurement of thermal conductivity of styrene-based resin foam molded body). The weight (g) of the sample was measured, and the length, width, and thickness were measured using a caliper. The volume (cm) of the sample was calculated from each measured dimension. 3 ) was calculated, and the expansion ratio was calculated according to the following formula. Expansion ratio (cm 3 / g) = sample volume (cm 3 ) / sample weight (g) As mentioned above, the unit of expansion ratio for styrene-based resin foam moldings is conventionally expressed as "cm 3 It is also expressed as " / g".

[0132] (Flame retardancy evaluation) The produced resin foam molded article was allowed to stand at 70° C. for 168 hours and then at 23° C. for 24 hours, after which the oxygen index was measured in accordance with JIS K7201.

[0133] (Method for measuring average cell diameter of styrene-based resin foam molded products) The styrene-based resin foam molded body was cut with a razor and the cross section was observed with an optical microscope. The number of cells present within a 1,000 μm × 1,000 μm square area of ​​the cross section was counted, and the value measured using the following formula (area average diameter) was taken as the average cell diameter. The average cell diameter of five samples was measured, and the average was taken as the average cell diameter of the standard. Average cell diameter (μm) = 2 × [1,000 μm × 1,000 μm / (number of cells × π)] 1 / 2

[0134] (Heat dimensional change rate) A sample of 150 mm length x 150 mm width x 25 mm thickness was cut out from the obtained styrene-based resin foam molded article. The sample was measured for thermal dimensional change in the length direction and width direction before and after heating at 90°C for 48 hours according to JIS K 6767:1999 (dimensional stability at high temperatures: Method B) based on the following formula. The larger of the measured thermal dimensional change in the length direction and width direction was then taken as the thermal dimensional change. S=|(L1 -L 0 )| / L 0 ×100 S: Heat dimensional change rate (%), L 1 : Dimensions after heating (mm), L 0 : Dimensions before heating (mm)

[0135] Example 1 [Preparation of expandable styrene resin particles] 93 parts by weight of methacrylic acid modified heat-resistant polystyrene resin (PS Japan Co., Ltd.; G9001), 4.5 parts by weight of graphite (Marutoyo Foundry Co., Ltd., flake graphite SGP-40B), and 2.5 parts by weight of bromine-based flame retardant (Daiichi Kogyo Seiyaku Co., Ltd., GR-170p (mixture of 2,2-bis[4-(2,3-dibromo-2-methylpropoxy)-3,5-dibromophenyl]propane and stabilizer)) were fed into a 40 mm diameter co-rotating intermeshing twin screw extruder (first extruder). The cylinder temperature after the raw material feed section of the twin screw extruder was set to 200°C, and the feed materials were melt-kneaded. Next, 8.0 parts by weight of mixed pentane (a mixture of 80% by weight of n-pentane and 20% by weight of isopentane (manufactured by SK Sangyo Co., Ltd.)) serving as a foaming agent was injected into the middle part of the cylinder after the raw material feed section of the twin-screw extruder relative to 100 parts by weight of the molten material obtained by melt kneading, and further melt kneaded.

[0136] The resulting thermoplastic resin melt (thermoplastic resin melt impregnated with a foaming agent) was then fed to a single-screw extruder (second extruder) with a diameter of 90 mm through a continuous pipe set at 250°C. A gear pump set at a temperature of 180°C and a diverter valve were connected to the tip of the single-screw extruder, and a die set at a temperature of 250°C, having 60 small holes with a diameter of 0.65 mm and a land length of 5.0 mm, was connected to the downstream side of the diverter valve. The cylinder temperature of the single-screw extruder was set to 180°C to knead the thermoplastic resin melt, and the melt obtained by melt kneading was extruded from the die connected to the tip of the single-screw extruder at an extrusion (discharge) rate of 60 kg / hr into pressurized water at a temperature of 80°C and a water pressure of 1.2 MPa.

[0137] Immediately after that, the molten material was cut into particles using a rotary cutter with a blade. This resulted in the formation of expandable styrene resin particles for in-mold molding. The average particle weight of the resulting expandable styrene resin particles was 1 mg.

[0138] [Formation of pre-expanded particles] The obtained expandable styrene-based resin particles were put into a pre-expanding machine, and steam of 0.1 MPa was introduced to expand the particles. This resulted in the formation of pre-expanded particles. The bulk expansion ratio of the obtained pre-expanded particles was 50 times (cc / g).

[0139] [Preparation of expanded bead foam] The obtained pre-expanded particles were filled into a mold (mold for in-mold molding) attached to a molding machine for styrene foam, and steam of 0.12 MPa was introduced to expand the mold inside. After that, the mold was cooled with water until the pressure of the resin foam molding in the mold pressing the mold became 0.015 MPa (gauge pressure), and a styrene-based resin foam molding with a length of 400 mm, width of 400 mm, thickness of 25 mm, and an expansion ratio of 50 times was produced.

[0140] The evaluation results of the obtained resin foam molded articles are shown in Table 1.

[0141] Example 2 A styrene resin foam molded article was produced in the same manner as in Example 1, except that the amounts were changed to 88 parts by weight of methacrylic acid modified heat-resistant polystyrene resin (G9001 manufactured by PS Japan Co., Ltd.) and 9.5 parts by weight of graphite (flake graphite SGP-40B manufactured by Marutoyo Foundry Co., Ltd.). Evaluation was performed in the same manner as in Example 1, and the measurement and evaluation results are shown in Table 1.

[0142] Comparative Example 1 A styrene-based resin foam molded article was produced in the same manner as in Example 1, except that graphite, a radiation suppressant, was not used and talc (Talc Powder PK-C, manufactured by Hayashi Kasei Co., Ltd.) was used instead. Evaluation was performed in the same manner as in Example 1, and the measurement and evaluation results are shown in Table 1.

[0143] Comparative Example 2 A styrene resin foam molded article was produced in the same manner as in Example 1, except that the methacrylic acid-modified heat-resistant polystyrene resin (manufactured by PS Japan Co., Ltd.; G9001) was replaced with a polystyrene resin (manufactured by PS Japan Co., Ltd.; 680). Evaluation was performed in the same manner as in Example 1, and the measurement and evaluation results are shown in Table 1.

[0144] [Table 1]

[0145] The results in Table 1 show that it is possible to obtain a styrene-based foamed resin molding for roof insulation structures that can suppress an increase in thermal conductivity when the temperature rises and that can suppress dimensional changes at high temperatures. [Industrial Applicability]

[0146] The present invention can be used for roof insulation technology for wooden buildings. [Explanation of symbols]

[0147] 1 Rafter 2, 2B, 2C Insulation 2b Low emissivity layer 3. 3A Roofing materials 4 Roof underlayment 5. Roof Finishing Materials 6 Groove 7 Slit 8 Ventilated Rafters 9 Ventilation Channel 10, 10A, 10B, 10C Roof insulation structure

Claims

1. A roof insulation structure for a wooden building, A number of rafters; Insulation material; A roofing material; The insulation is provided between or on adjacent rafters; The roofing material is laid on the upper surface side of the thermal insulation material, A roof insulation structure, wherein the insulation material comprises a resin foam molded body, the resin foam molded body containing a radiation heat transfer inhibitor and having a dimensional change rate of 1.0% or less before and after heating at 90°C for 48 hours.

2. the radiation heat transfer inhibitor is at least one selected from the group consisting of graphite, carbon black, activated carbon, graphene, carbon nanotubes, coke, titanium oxide, aluminum, and copper; 2. The roof insulation structure according to claim 1, wherein the content of the radiation heat transfer inhibitor is 1 to 20 parts by weight per 100 parts by weight of the resin foam molding.

3. The roof insulation structure according to claim 1 or 2, wherein the resin constituting the resin foam molded body includes a styrene-based resin.

4. The roof insulation structure according to claim 3 , wherein the styrene-based resin has a structural unit derived from (meth)acrylic acid.

5. The roof insulation structure according to claim 1 or 2, wherein the resin foam molding is a foam bead molding.

6. one or more ventilation passages; 3. The roof insulation structure according to claim 1, wherein the air passage is provided between the insulation material and the roof material so as to be parallel to the rafters.

7. 7. The roof insulation structure according to claim 6, wherein the air passage is a groove formed in an upper surface of the insulation material.

8. Equipped with ventilation rafters, The ventilation rafter is provided on the upper surface side of the insulation material, 7. The roof insulation structure according to claim 6, wherein the air passage is formed by the roof material, the ventilation rafter, and the insulation material.

9. The insulation material is provided between adjacent rafters, The end of the insulation material facing at least one of the two adjacent rafters has a slit, the slit extends parallel to the rafters and is elastically deformable; 3. The roof insulation structure according to claim 1, wherein the insulation material is elastically fitted closely between two adjacent rafters by the elastic force of the slits.

10. The roof insulation structure according to claim 1 or 2, further comprising a low emissivity layer on the upper side of the insulation material.

11. 11. The roof insulation structure of claim 10, wherein the low emissivity layer comprises at least one selected from the group consisting of aluminum, copper, nickel, and chromium.

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