Roof underlaying material and use thereof

Abstract

To provide a roof underlaying material excellent in lightweight properties.SOLUTION: A first uneven layer 2 which is disposed on a side in contact with a asphalt base material and contains first particles, a first asphalt waterproof layer 3 which is laminated on the first uneven layer 2 and is formed of a first asphalt composition containing first asphalt, an asphalt-impregnated fiber layer 4 which is laminated on the first asphalt waterproof layer 3 and is formed of a fiber structure containing third asphalt, in the roof underlaying material 1 including a second asphalt waterproof layer 5 formed of a second asphalt composition containing second asphalt and a second uneven layer 6 laminated on the second asphalt waterproof layer 5 and containing second particles, porous inorganic particles are used for at least one of the first particles and the second particles.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a roof underlayment for covering a roof substrate of a building or structure and its use. [Background technology]

[0002] Traditionally, roofs in Japanese houses have typically been constructed with asphalt roofing interposed between a roofing base material such as plywood or sheathing boards and a roofing material such as roof tiles, as a waterproof underlayment.

[0003] It is common for this asphalt roofing to have its surface covered with silica sand. For example, Japanese Patent Laid-Open Publication No. 11-21770 (Patent Document 1) discloses a roof underlayment characterized by having a core made of synthetic fiber nonwoven fabric impregnated with asphalt, with waterproof and adhesive layers on both sides made of asphalt mixed with 1 to 15% styrene-butadiene-styrene block copolymer, one side of which is covered with a mineral powder layer, and the other side is covered with synthetic nonwoven fabric that has been given water repellency.

[0004] In addition, Japanese Patent Application Laid-Open No. 2001-73510 (Patent Document 2) discloses a roof underlayment material characterized by comprising a sheet material, asphalt attached to the sheet material at a predetermined thickness, and glass particles attached to the asphalt with rounded corners. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 11-21770 [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-73510 Summary of the Invention [Problem to be solved by the invention]

[0006] However, asphalt roofing coated with a layer of mineral powder such as silica sand or glass particles, as in Patent Documents 1 and 2, is heavy. In recent years, Japan has been experiencing a decline in population and an aging society, and the working age of workers at construction sites is also increasing. Therefore, at construction sites for roof underlayment, where work at heights is required, the dangers of handling heavy objects have been pointed out, and there is a trend toward a demand for lighter asphalt roofing that is easier to work with.

[0007] Furthermore, in Patent Documents 1 and 2, due to the nature of the asphalt used, the temperature of the asphalt roofing increases due to sunlight during construction work, which raises the temperature of the work site and makes the asphalt sticky, making it difficult to handle. In particular, as asphalt roofing construction is a dangerous job performed on a roof, the reduced ease of handling is a major problem. Furthermore, if the asphalt becomes sticky, it is likely to contaminate the work environment and the asphalt roofing itself is also prone to damage during construction.

[0008] Therefore, an object of the present invention is to provide a roof underlayment that is excellent in lightness and uses thereof.

[0009] Another object of the present invention is to provide a roof underlayment material that is lightweight and can suppress temperature rise during installation, and uses thereof. [Means for solving the problem]

[0010] As a result of intensive research to achieve the above-mentioned objectives, the inventors discovered that the lightness of a roof underlayment can be improved by having an uneven layer containing porous inorganic particles, and thus completed the present invention.

[0011] That is, the present invention includes the following aspects.

[0012] Aspect [1]: A roof underlayment material that is laid on a roof substrate and has an uneven layer containing porous inorganic particles.

[0013] Aspect [2]: A roof underlayment according to claim 1, which includes a waterproof layer containing asphalt, and the uneven layer is formed on at least one surface of the waterproof layer.

[0014] Aspect [3]: A roof underlayment material, wherein the uneven layer comprises a first uneven layer containing first particles and a second uneven layer containing second particles, The first uneven layer is disposed on the side that comes into contact with the roof underlayment; A first asphalt waterproofing layer laminated on the first uneven layer and formed of a first asphalt composition containing a first asphalt; an asphalt-impregnated fiber layer laminated on the first asphalt waterproof layer and formed of a fiber structure containing a third asphalt; A second asphalt waterproofing layer is laminated on the asphalt-impregnated fiber layer and is formed of a second asphalt composition containing a second asphalt; The second uneven layer is laminated on the second asphalt waterproofing layer, and The roof underlayment material according to aspect [1] or [2], wherein at least one of the first particles and the second particles comprises porous inorganic particles.

[0015] Aspect [4]: ​​The roof underlayment according to aspect [3], wherein the first particles include first porous inorganic particles and the second particles include second porous inorganic particles.

[0016] Aspect [5]: The roof underlayment material according to any one of Aspects [1] to [4], wherein the porous inorganic particles are porous glass particles.

[0017] Aspect [6]: The roof underlayment material according to any one of Aspects [1] to [5], wherein the porous inorganic particles are glass foam.

[0018] Aspect [7]: The bulk density of the porous inorganic particles is 1.1 g / cm 3 The roof underlayment material according to any one of the above aspects [1] to [6] below.

[0019] Aspect [8]: The specific surface area of ​​the porous inorganic particles is 0.35 m 2 The roof underlayment material according to any one of the above aspects [1] to [7], wherein the viscosity is 1 / g or more.

[0020] Aspect [9]: The roof underlayment material according to any one of Aspects [1] to [8], wherein the porous inorganic particles have an average pore size of 35 μm or less.

[0021] Aspect

[10] : The roof underlayment material according to any one of Aspects [1] to [9], wherein the porous inorganic particles have an average pore size of 30 μm or less.

[0022] Aspect

[11] : The roof underlayment material according to any one of Aspects [1] to

[10] , wherein the mercury intrusion amount of the porous inorganic particles is 0.45 cc / g or more.

[0023] Aspect

[12] : The roof underlayment material according to any one of Aspects [1] to

[11] , wherein the porous inorganic particles have an average particle size of 40 to 500 μm.

[0024] Aspect

[13] : The porous inorganic particles have a basis weight of 200 g / m 2 The roof underlayment material according to any one of the above aspects [1] to

[12] below.

[0025] Aspect

[14] : A roof underlayment material according to any one of Aspects [3] to

[13] , wherein the penetration of the first asphalt composition and the second asphalt composition is 50 or less at 25°C.

[0026] Aspect

[15] : A roof underlayment according to any one of aspects [3] to

[14] , wherein the first asphalt composition comprises 1 to 100 parts by mass of a first filler per 100 parts by mass of the first asphalt, and the second asphalt composition comprises 1 to 100 parts by mass of a second filler per 100 parts by mass of the second asphalt.

[0027] Aspect

[16] : A method for improving the workability of roof underlayment by forming an uneven layer containing porous inorganic particles on at least one surface of a waterproofing layer containing asphalt. [Effects of the Invention]

[0028] In the present invention, the roof underlayment has an uneven layer containing porous inorganic particles, which improves its lightness. In particular, in a roof underlayment having first and second asphalt waterproofing layers on both sides of an asphalt-impregnated fibrous layer, an uneven layer containing porous inorganic particles is formed on one surface of the asphalt waterproofing layer, which not only improves its lightness but also suppresses the temperature rise of the roof underlayment during installation. Therefore, in addition to improving its lightness, stickiness of the roof underlayment can be suppressed and handling can be improved, thereby improving installation efficiency. [Brief explanation of the drawings]

[0029] [Figure 1] FIG. 1 is a schematic cross-sectional view showing an example of a roof underlayment material of the present invention. [Figure 2] FIG. 2 is a scanning electron microscope photograph (50x magnification) of the glass foam A used in the examples. DETAILED DESCRIPTION OF THE INVENTION

[0030] [Roof underlayment] The roof underlayment of the present invention has an uneven layer containing porous inorganic particles, thereby improving its lightness. The roof underlayment of the present invention is preferably a roof underlayment that includes a waterproof layer containing asphalt and has the uneven layer formed on at least one surface of the waterproof layer.

[0031] The roof underlayment material of the present invention will be described below with reference to the drawings: Figure 1 is a schematic cross-sectional view showing an example of the roof underlayment material of the present invention.

[0032] The roof underlayment 1 shown in Figure 1 is formed of a first uneven layer 2 on the side that comes into contact with the roofing base material, a first asphalt waterproofing layer 3 laminated on this uneven layer 2, an asphalt-impregnated fiber layer 4 laminated on this first asphalt waterproofing layer 3, a second asphalt waterproofing layer 5 laminated on this asphalt-impregnated fiber layer 4, and a second uneven layer 6 laminated on this second asphalt waterproofing layer 5, and at least one of the first uneven layer 2 and the second uneven layer 6 contains porous inorganic particles, thereby improving the lightness. The roof underlayment 1 is in sheet form, and its surface shape may be quadrangular, such as square or rectangular, but a long shape (especially a long rectangular shape) is preferred from the standpoint of workability, etc.

[0033] The roof underlayment 1 of the present invention is laid on a roof underlayment, such as plywood or sheathing board, with the first uneven layer 2 in contact with the roof underlayment in order to improve the waterproofing of the roof. That is, because the installation of the roof underlayment of the present invention is performed on a high, dangerous roof, it must be installed safely and easily. To improve work safety, the roof underlayment must not only be lightweight, but also be less sticky and easier to handle. In particular, roof underlayment installation is often performed on sunny days. However, on roofs exposed to direct sunlight, the roof underlayment heats up and the asphalt becomes sticky, making the asphalt roofing more susceptible to damage and reducing its ease of handling. In contrast, in the present invention, an uneven layer containing specific porous microparticles is formed on the surface of both the first and second asphalt waterproofing layers, and the first and second asphalt waterproofing layers are prepared from a specific asphalt composition, thereby improving not only lightness but also handleability.

[0034] (First and second uneven layers) The first and second uneven layers each contain particles (first or second particles), which impart an uneven shape to the surface of the roof underlayment, reducing its slipperiness and improving safety and workability during installation. The uneven layers also act as weights (weightstones) on the roof underlayment, making it easy to secure the roof underlayment to the installation location.

[0035] In particular, in the present invention, the particles contain porous inorganic particles, which can improve the lightness and workability.

[0036] Examples of inorganic materials constituting the porous inorganic particles include simple metals (e.g., iron, copper, tin, zinc, nickel, stainless steel, etc.), inorganic oxides or metal oxides [e.g., beryllium oxide, silicon oxide or silica, aluminum oxide or alumina, titania, zirconia, magnesia, manganese oxide, iron oxide, ferric oxide, iron tetraoxide, zinc oxide, zinc oxide, copper oxide, tin oxide, antimony oxide, cerium oxide, tin-doped indium oxide (ITO), etc.], nitrogen compounds (e.g., boron nitride, aluminum nitride, silicon nitride, carbon nitride, titanium nitride, etc.), carbon compounds (e.g., silicon carbide, fluorine carbide, boron carbide, titanium carbide, tungsten carbide, etc.), metals Examples of suitable inorganic fillers include salts (e.g., metal carbonates such as calcium carbonate, calcium bicarbonate, barium carbonate, and magnesium carbonate; sulfates such as barium sulfate, calcium sulfate, aluminum sulfate, and calcium sulfite; and metal hydroxides such as magnesium hydroxide), minerals (e.g., steelmaking slag, slate chips, talc, mica, zeolite, ferrite, tourmaline, diatomaceous earth, silica sand, calcined silica earth, activated clay, shirasu, kaolin, pyrophyllite, sericite, bentonite, smectite, montmorillonite, clay, red iron oxide, quartz, and wollastonite), glasses (e.g., soda-lime glass, lead glass, borosilicate glass, and silica glass), and silicon.

[0037] These inorganic materials can be used alone or in combination. Among these, minerals and glasses are preferred, with glasses such as soda-lime glass being particularly preferred due to their excellent recyclability. As porous inorganic particles, porous mineral particles such as pumice powder and porous glass particles such as soda-lime glass are preferred, with porous glass particles being particularly preferred due to their excellent recyclability. Porous glass particles are lightweight and have higher thermal conductivity than minerals, but their porous structure can improve thermal insulation and light blocking properties. In particular, they exhibit thermal insulation properties comparable to those of porous mineral particles, which have low thermal conductivity.

[0038] The porous glass particles may be glass particles having a porous structure (interconnected hollow or open cell shape), but may also be glass foam.

[0039] Porous inorganic particles (especially porous glass particles such as glass foam) have a low bulk density, for example, 1.1 g / cm 3 It may be less than 1 g / cm 3 or less, more preferably 0.8 g / cm 3 Specifically, it is 0.1 to 1.1 g / cm 3 , preferably 0.3 to 1 g / cm 3 , and more preferably 0.4 to 0.8 g / cm 3 , more preferably 0.5 to 0.7 g / cm 3 , and most preferably 0.55 to 0.65 g / cm 3 If the bulk density is too high, there is a risk that the lightness will decrease.

[0040] In this specification and claims, the bulk specific gravity of the porous inorganic particles can be measured in accordance with JIS Z 2504:2020 using a funnel with an orifice diameter of 2.5 mm and a funnel angle of 60 degrees.

[0041] The specific surface area of ​​the porous inorganic particles (particularly, porous glass particles) is, for example, 0.35 m 2 / g or more, and from the viewpoint of improving the handling property in addition to the light weight, it is preferably 0.5 m 2 / g or more, more preferably 1m 2 / g or more, more preferably 2m 2 / g or more, specifically 0.35 to 10m 2 / g, preferably 0.5 to 8m 2 / g, more preferably 1 to 5m 2 / g, more preferably 2 to 4 m 2 / g, most preferably 2.5 to 3.5 m 2 If the specific surface area is too small, there is a risk that the lightness and ease of handling will decrease.

[0042] In this specification and claims, the specific surface area of ​​the porous inorganic particles can be measured using a specific surface area meter in accordance with JIS Z 8830 "Method for measuring the specific surface area of ​​powders (solids) by gas adsorption," and in detail, can be measured by the method described in the examples below.

[0043] The mercury intrusion amount of the porous inorganic particles (particularly, porous glass particles) may be, for example, 0.45 cc / g or more, preferably 0.5 cc / g or more, and from the viewpoint of improving not only lightness but also handleability, more preferably 0.55 cc / g or more, specifically 0.45 to 1 cc / g, preferably 0.5 to 0.9 cc / g, still more preferably 0.53 to 0.8 cc / g, more preferably 0.55 to 0.7 cc / g, and most preferably 0.57 to 0.65 cc / g. If the mercury intrusion amount is too small, there is a risk that lightness and handleability will be reduced.

[0044] The average pore size of the porous inorganic particles (particularly, porous glass particles) may be 35 μm or less, and from the viewpoint of improving handleability in addition to lightness, it is preferably 30 μm or less, more preferably 20 μm or less, and even more preferably 10 μm or less, specifically 1 to 35 μm, preferably 2 to 30 μm, even more preferably 3 to 20 μm, more preferably 5 to 10 μm, and most preferably 6 to 8 μm. If the average pore size is too large, there is a risk of reduced handleability.

[0045] In this specification and claims, the mercury intrusion amount and average pore size of porous inorganic particles can be measured using a mercury intrusion porosimeter in accordance with JIS R 1655 "Test method for pore size distribution of molded fine ceramics by mercury intrusion method," and in detail, can be measured by the method described in the examples below.

[0046] The shape of the porous inorganic particles (particularly, porous glass particles) is not particularly limited as long as it is granular, and examples thereof include spherical or approximately spherical, ellipsoidal or rod-like, polyhedral (e.g., cubic, rectangular, tetrahedral (pyramidal)), flat (plate-like, scaly, or thin), and irregular shapes. Of these, irregularly shaped granular shapes are commonly used.

[0047] The porous inorganic particles (particularly porous glass particles) may have an average particle size of 10 to 500 μm, preferably 20 to 400 μm, and further preferably 25 to 300 μm, and from the viewpoint of improving not only lightness but also handleability, more preferably 28 to 100 μm, and most preferably 30 to 50 μm. If the average particle size is too small, the uneven shape may be small and the surface may become slippery, while if it is too large, the lightness and handleability may be reduced.

[0048] The minimum particle size of the porous inorganic particles (particularly, porous glass particles) may be 1 μm or more, preferably 1.5 μm or more, and more preferably 2 μm or more, and the maximum particle size may be 1 mm or less, preferably 800 μm or less, and more preferably 400 μm or less.

[0049] In this specification and claims, the average particle size, minimum particle size, and maximum particle size of porous inorganic particles can be measured on a volume basis using a laser diffraction / scattering particle size distribution analyzer, and the average particle size is determined based on the median particle size (D 50 ) means

[0050] In the present invention, it is sufficient that at least one of the first particles and the second particles contains porous inorganic particles, and it is also possible that only the first particles contain porous inorganic particles, or only the second particles contain porous inorganic particles. However, it is preferable that both the first particles and the second particles contain porous inorganic particles, in order to improve the lightness and workability.

[0051] In the first particles or the second particles, the particles other than the porous inorganic particles may be either non-porous inorganic particles or organic particles. The other particles may be organic particles such as silicone-based resin particles, cross-linked polyolefin-based resin particles, cross-linked polymethyl methacrylate-based resin particles, melamine-based resin particles, or cross-linked polystyrene-based resin particles, but non-porous inorganic particles are preferred in terms of heat resistance, etc.

[0052] Examples of inorganic materials constituting non-porous inorganic particles include the inorganic materials exemplified as inorganic materials constituting the porous inorganic particles. The inorganic materials can be used alone or in combination of two or more. Among the inorganic materials, minerals and glasses are preferred. Preferred non-porous inorganic particles are mineral particles such as silica sand and glass particles such as waste glass.

[0053] The shape of the other particles (particularly non-porous inorganic particles) is not particularly limited as long as it is granular, and examples thereof include spherical or approximately spherical, ellipsoidal or rod-like, polyhedral (e.g., cubic, rectangular, tetrahedral (pyramidal)), flat (plate-like, scaly, or thin), and irregular shapes. Of these, irregularly shaped granular shapes are commonly used.

[0054] The average particle size of the other particles (particularly non-porous inorganic particles) is, for example, 10 to 1000 μm, preferably 100 to 800 μm, and more preferably 120 to 500 μm.

[0055] At least one of the first particles and the second particles may contain porous inorganic particles, and the other may be a particle consisting solely of other particles. When only one of the first particles and the second particles contains porous inorganic particles, either the first particles or the second particles may contain porous inorganic particles.

[0056] When the first particles and / or the second particles include porous inorganic particles (first and / or second porous inorganic particles), the proportion of the porous inorganic particles in the first particles or second particles may be 10% by mass or more, preferably 50% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, and most preferably 100% by mass (the first particles or the second particles may be formed solely of porous inorganic particles).

[0057] The first uneven layer and the second uneven layer may further contain other components (first other components or second other components) in addition to the first particles or second particles, as long as the effects of the present invention are not impaired.

[0058] Other components include an organic component (first organic component or second organic component) that coats the exposed surface of the first particle or second particle, and an asphalt composition (first asphalt composition or second asphalt composition described below) in which the first asphalt waterproofing layer or second asphalt waterproofing layer has seeped onto the surface of the first particle or second particle.

[0059] Examples of the organic component include polyolefins, vinyl polymers (e.g., polyvinyl chloride, acrylic resins, polyvinyl acetate, ethylene-vinyl acetate copolymers, ethylene-vinyl alcohol copolymers, ethylene-acrylic acid copolymers, ethylene-methyl acrylate copolymers, ethylene-ethyl acrylate copolymers, etc.), polyamides, polyesters, synthetic rubbers or elastomers (e.g., polybutadiene, polyisoprene, styrene-butadiene copolymers, etc.), natural rubbers, tackifiers (e.g., terpene resins, rosin resins such as natural rosin and modified rosin, petroleum resins, modified olefin polymers, etc.), and oils and fats (e.g., naphthenic raw oils, etc.). These organic components can be used alone or in combination. Of the organic components, vinyl polymers are preferred, and (meth)acrylic polymers are preferred.

[0060] Examples of the (meth)acrylic polymer include poly(meth)acrylic acid or a salt thereof, methyl methacrylate-(meth)acrylic acid copolymer, acrylic acid-polyvinyl alcohol copolymer (saponified acrylic acid-vinyl acetate copolymer), styrene-(meth)acrylic acid copolymer, and styrene-(meth)acrylic acid C 1-10 Alkyl ester copolymer, vinyl acetate-(meth)acrylic acid copolymer, vinyl acetate-(meth)acrylic acid C 1-10 Examples of (meth)acrylic polymers include alkyl ester copolymers. These (meth)acrylic polymers are available in the form of emulsions, making them easy to handle. These (meth)acrylic polymers can be used alone or in combination of two or more. Among these, copolymers with styrene, such as styrene-(meth)acrylic acid copolymers, are preferred because of their excellent mechanical properties.

[0061] The proportion of the first particles or the second particles in the entire first uneven layer or the second uneven layer is 50% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, and may be 100% by mass (the uneven layer may be formed solely of the first particles or the second particles).

[0062] When the first uneven layer and / or the second uneven layer contains porous inorganic particles, the basis weight of the porous inorganic particles in each uneven layer is 150 g / m 2 It may be less than 100 g / m, and from the viewpoint of improving the handling property in addition to the light weight, it is preferable to use 100 g / m 2 or less, more preferably 80 g / m 2 Specifically, it is 10 to 150 g / m 2 , preferably 20 to 100 g / m 2 , and more preferably 25 to 80 g / m 2 , more preferably 30 to 50 g / m 2 , and most preferably 35 to 40 g / m 2 If the weight per unit area is too high, there is a risk that the lightweight property will decrease.

[0063] The arithmetic mean roughness Ra of the surface of the uneven layer (the surface not in contact with the first asphalt waterproofing layer or the second asphalt waterproofing layer) is 20 μm or more, for example, 21 to 100 μm, preferably 22 to 50 μm, and more preferably 23 to 30 μm. If Ra is too small, there is a risk that the surface will be slippery.

[0064] The maximum height Rz of the surface of the uneven layer (the surface not in contact with the first asphalt waterproofing layer or the second asphalt waterproofing layer) is 100 μm or more, for example 110 to 500 μm, preferably 130 to 300 μm, and more preferably 150 to 200 μm. If Rz is too small, there is a risk that the surface will become slippery.

[0065] In this specification and claims, the arithmetic mean roughness Ra and maximum height Rz can be measured by a method in accordance with JIS B 0601, and more specifically, by the method described in the examples below.

[0066] The average thickness of each of the first and second uneven layers may be 5 mm or less, for example, 0.05 to 3 mm, preferably 0.05 to 2 mm, further preferably 0.05 to 1 mm, even more preferably 0.05 to 0.5 mm, and most preferably 0.05 to 0.2 mm. If the uneven layer is too thin, the slip prevention effect and weight effect may be reduced, and if it is too thick, the lightness may be reduced.

[0067] In this specification and claims, the average thickness of the irregular layer is determined by measuring the thickness at any 10 locations and calculating the average value.

[0068] (fiber layer) The roof underlayment of the present invention may have a fibrous layer formed of a fibrous structure laminated thereon instead of the uneven layer (first uneven layer or second uneven layer).

[0069] Examples of fibers constituting the fiber structure include natural fibers (cellulose fibers such as cotton and hemp), regenerated fibers (rayon, etc.), semi-synthetic fibers (cellulose ester fibers, etc.), synthetic fibers (polyolefin fibers (polyethylene fibers, polypropylene fibers, etc.), styrene fibers, polytetrafluoroethylene fibers, acrylic fibers, vinyl alcohol fibers (ethylene vinyl alcohol fibers, etc.), polyester fibers (polyalkylene-arylate fibers such as polyethylene terephthalate and polyethylene naphthalate, wholly aromatic polyester fibers such as liquid crystal polyester fibers, etc.), polyamide fibers (aliphatic polyamide fibers such as polyamide 6 and polyamide 66, wholly aromatic polyamide fibers such as aramid fibers, etc.), polyurethane fibers, and inorganic fibers (carbon fibers, glass fibers, etc.). The synthetic fibers may also be composite fibers made by combining different resin components. These fibers can be used alone or in combination of two or more. Among these fibers, synthetic fibers such as polyolefin fibers and polyester fibers, and inorganic fibers are commonly used, but poly-C fibers such as polyethylene terephthalate fibers are preferred in terms of UV resistance and other properties. 2-4 Alkylene-C 6-12Arylate fibers are preferred.

[0070] The fiber structure includes woven fabric, knitted fabric, nonwoven fabric, net, paper, etc. The fiber structure may be a composite (laminate) of these. Among these, nonwoven fabric is preferred from the viewpoint of mechanical properties, etc.

[0071] The basis weight of the fiber structure is, for example, 10 to 1000 g / m 2 , preferably 12 to 500 g / m 2 , and more preferably 15 to 100 g / m 2 , more preferably 20 to 50 g / m 2 is.

[0072] (First and second asphalt waterproofing layers) The first and second asphalt waterproofing layers are each formed of an asphalt composition (first or second asphalt composition) and have waterproof properties. In the present invention, by laminating the first and second uneven layers on the first and second asphalt waterproofing layers, not only can the lightness of the roof underlayment be improved, but the stickiness of the roof underlayment can also be suppressed, improving its handleability.

[0073] The first and second asphalt compositions may be different from each other, but are preferably the same. The first and second asphalt compositions each comprise asphalt (first or second asphalt).

[0074] Examples of asphalt include natural asphalt (lake asphalt, rock asphalt, oil sand, asphaltite, etc.) and petroleum asphalt (straight asphalt, blown asphalt, etc.). These asphalts can be used alone or in combination of two or more. Among these, petroleum asphalts such as waterproofing asphalt type 3 and blown asphalt are preferred.

[0075] The penetration (1 / 10 mm) of the first and second asphalts is not particularly limited, but can be selected from a range of about 0 to 300, respectively, in a method conforming to JIS K 2207-1996 (25°C), and is, for example, 10 to 280, preferably 10 to 200, further preferably 10 to 150, even more preferably 10 to 100, and most preferably 15 to 30. If the penetration is too small, it may be difficult to form a uniform layer, and conversely, if it is too large, handling may be impaired.

[0076] The softening points of the first and second asphalts can each be selected from a range of about 50 to 200° C. in accordance with JIS K 2207-1996, and are, for example, 70 to 180° C., preferably 80 to 150° C., and more preferably 100 to 120° C. If the softening point is too low, it may be difficult to form a uniform layer, and if it is too high, handling may be impaired.

[0077] The proportion of the first and second asphalts in the first and second asphalt compositions may be 30% by mass or more (particularly 50% by mass or more), for example 30 to 95% by mass, preferably 40 to 90% by mass, further preferably 50 to 85% by mass, more preferably 60 to 80% by mass, and most preferably 65 to 75% by mass. If the proportion of asphalt is too low, there is a risk that waterproofing properties will decrease.

[0078] The first and second asphalt compositions preferably further contain a filler (first filler or second filler) to reduce stickiness of the roof underlayment and improve handling. Fillers include inorganic fillers (inorganic fillers) and organic fillers (organic fillers).

[0079] Examples of inorganic fillers include metal particles (powders) such as iron, copper, tin, zinc, nickel, and stainless steel; metal oxide particles such as iron oxide, ferric oxide, iron tetraoxide, ferrite, tin oxide, zinc oxide, zinc oxide, copper oxide, and aluminum oxide; metal salt particles such as barium sulfate, calcium sulfate, aluminum sulfate, calcium sulfite, calcium carbonate, calcium bicarbonate, barium carbonate, and magnesium hydroxide; mineral particles such as steelmaking slag, slate chips, mica, clay, talc, wollastonite, diatomaceous earth, silica sand, pumice powder, silica balloons, and shirasu balloons; glass particles such as waste glass, glass foam, and glass balloons; and inorganic fibers such as glass fiber and carbon fiber. These inorganic fillers can be used alone or in combination.

[0080] Examples of organic fillers include wood flour, pulp, natural fibers (cotton, hemp, etc.), recycled fibers (rayon, etc.), cross-linked resin particles (cross-linked polyethylene particles, cross-linked polystyrene particles, cross-linked acrylic particles, etc.), synthetic fibers (polyester fibers, polyamide fibers, etc.), etc. These organic fillers can be used alone or in combination of two or more.

[0081] These fillers can be used alone or in combination of two or more. Among these fillers, inorganic fillers are preferred, metal salt particles are more preferred, and metal carbonate particles such as calcium carbonate are even more preferred, from the viewpoint of easily improving lightness and handleability.

[0082] The shape of the filler (particularly, inorganic filler) is not particularly limited as long as it is granular, and examples thereof include spherical or approximately spherical, ellipsoidal or rod-like, polyhedral (e.g., cubic, rectangular, tetrahedral (pyramidal)), flat (plate-like, scaly, or thin), and irregular shapes. Of these, irregularly shaped granular shapes are commonly used.

[0083] The average particle size of the filler (particularly inorganic filler) is, for example, 10 to 500 μm, preferably 20 to 300 μm, further preferably 30 to 200 μm, even more preferably 50 to 150 μm, and most preferably 60 to 100 μm. If the average particle size is too small, the effect of improving handleability may be reduced, and if it is too large, waterproofness may be reduced.

[0084] The maximum particle size of the filler (particularly, inorganic filler) may be 5 mm or less, preferably 3 mm or less, and more preferably 1 mm or less.

[0085] In this specification and claims, the average particle size and maximum particle size of the filler can be measured on a volume basis using a laser diffraction / scattering particle size distribution analyzer, and the average particle size is determined based on the median particle size (D 50 ) means

[0086] The bulk density of fillers (especially inorganic fillers) is 10 g / cm 3 or less, for example, 1 to 10 g / cm 3 , preferably 1.2 to 5 g / cm 3 , and more preferably 1.5 to 4 g / cm 3 , more preferably 2 to 3.5 g / cm 3 , and most preferably 2.5 to 3 g / cm 3 If the bulk density of the filler is too high, there is a risk that the lightweight property will decrease.

[0087] The proportion of the first and second fillers is, for example, 1 to 100 parts by mass, preferably 10 to 80 parts by mass, further preferably 20 to 60 parts by mass, even more preferably 30 to 50 parts by mass, and most preferably 35 to 45 parts by mass, per 100 parts by mass of the first or second asphalt, respectively. If the filler proportion is too low, the effect of improving handleability may be reduced, and conversely, if it is too high, there is a risk that adhesion to the uneven layer may be reduced.

[0088] The first and second asphalt compositions may each further contain an organic modifier (first or second organic modifier) ​​in order to improve the bonding strength with the irregular layer.

[0089] Examples of organic modifiers include polyolefins, vinyl polymers (e.g., polyvinyl chloride, acrylic resins, polyvinyl acetate, ethylene-vinyl acetate copolymers, ethylene-vinyl alcohol copolymers, ethylene-acrylic acid copolymers, ethylene-methyl acrylate copolymers, ethylene-ethyl acrylate copolymers, etc.), polyamides, polyesters, synthetic rubbers or elastomers (e.g., polybutadiene, polyisoprene, styrene-butadiene copolymers, etc.), natural rubbers, tackifiers (e.g., terpene resins, rosin resins such as natural rosin and modified rosin, petroleum resins, modified olefin polymers, etc.), oils and fats (e.g., naphthenic raw oils, etc.). These organic modifiers can be used alone or in combination of two or more.

[0090] Of these organic modifiers, thermoplastic elastomers, tackifiers, and oils and fats are preferred, and styrene-diene copolymers such as styrene-butadiene-styrene block copolymers are particularly preferred.

[0091] The proportion of the first and second organic modifiers is, for example, 50 parts by mass or less, preferably 40 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 20 parts by mass or less (for example, 1 to 20 parts by mass) per 100 parts by mass of the first or second asphalt, respectively. If the proportion of the organic modifier is too high, there is a risk that waterproofing properties will decrease.

[0092] The first and second asphalt compositions may each further contain conventional additives. Examples of additives include stabilizers (heat stabilizers such as copper compounds, UV absorbers, light stabilizers, antioxidants, etc.), thickeners, flame retardants, plasticizers, antistatic agents, colorants, surfactants, dispersants, lubricants, crystallization rate retarders, glidants, antibacterial agents, insect repellents (termite repellents, mite repellents, etc.), preservatives (mold inhibitors, etc.), matting agents, heat storage agents, fragrances, fluorescent brighteners, and wetting agents. These additives can be used alone or in combination. In each of the first and second asphalt compositions, the total proportion of additives in the first or second asphalt composition is 50% by mass or less, preferably 0.01 to 30% by mass, and more preferably 0.1 to 10% by mass.

[0093] The penetration (1 / 10 mm) of the first and second asphalt compositions is not particularly limited, but can be selected from a range of about 0 to 300 when measured at 25°C according to a method in accordance with JIS K 2207-1996, and may be, for example, about 1 to 100. However, from the viewpoint of improving handleability, it may be 50 or less, and is preferably 2 to 50, further preferably 3 to 30, even more preferably 3 to 20, and most preferably 5 to 15. If the penetration is too small, it may be difficult to form a uniform layer, and conversely, if it is too large, handleability may be reduced.

[0094] The average thickness of each of the first and second asphalt waterproofing layers may be 0.7 mm or less, for example, 0.1 to 0.7 mm, preferably 0.15 to 0.65 mm, further preferably 0.2 to 0.6 mm, even more preferably 0.2 to 0.5 mm, and most preferably 0.2 to 0.4 mm. If the average thickness of the first or second asphalt waterproofing layer is too large, there is a risk that the lightweight properties will decrease.

[0095] (Asphalt-impregnated fiber layer) The asphalt-impregnated fibrous layer is formed of a fibrous structure containing asphalt (that is, a combination of a fibrous structure and a third asphalt contained within the fibrous structure).

[0096] Fiber structures include woven fabrics, knitted fabrics, nonwoven fabrics, nets, paper, etc. The fiber structure may also be a composite (laminate) of these. Of these, paper is preferred from the standpoint of economy, etc. The type of paper is not particularly limited, but base paper is preferred from the standpoint of economy, etc. As base paper, waste paper such as newspapers, magazines, and cardboard, as well as base paper recycled from cotton, fluff, etc. can be used.

[0097] The basis weight (basis weight) of the fiber structure (especially base paper, etc.) is 120 to 320 g / m 2 The thickness can be selected from a range of about 130 to 300 g / m 2 , preferably 140 to 280 g / m 2 , and more preferably 150 to 250 g / m 2 , more preferably 160 to 220 g / m 2 , and most preferably 180 to 200 g / m 2 If the basis weight is too large, the lightweight property may decrease and the workability may also decrease, and if it is too small, the mechanical properties may decrease.

[0098] Examples of asphalt (third asphalt) include the asphalts exemplified for the first and second asphalt waterproofing layers. The asphalts can be used alone or in combination. Among the asphalts, petroleum asphalts such as straight asphalt are preferred because they can be easily and uniformly impregnated into the fiber structure.

[0099] The penetration (1 / 10 mm) of the third asphalt is not particularly limited, but can be selected from a range of about 0 to 300 in a method (25°C) in accordance with JIS K 2207-1996, and is, for example, 50 to 280, preferably 50 to 250, further preferably 50 to 230, and even more preferably 50 to 200. If the penetration is too small, it may be difficult to uniformly penetrate the fiber structure.

[0100] The proportion of the third asphalt relative to 100 parts by mass of the fiber structure is, for example, 50 to 2000 parts by mass, preferably 80 to 1000 parts by mass, further preferably 100 to 800 parts by mass, even more preferably 100 to 500 parts by mass, and most preferably 100 to 200 parts by mass. If the proportion of the third asphalt is too low, there is a risk that waterproofing will decrease, and conversely, if it is too high, there is a risk that it will be difficult to uniformly penetrate the fiber structure.

[0101] The asphalt-impregnated fibrous layer may further contain other components such as fillers, organic modifiers, and conventional additives. Examples of fillers and organic modifiers include the organic modifiers and fillers exemplified in the sections on the first and second asphalt waterproofing layers. Examples of additives include the additives exemplified in the section on the asphalt waterproofing layer. The additives can be used alone or in combination. The total proportion of these other components in the asphalt-impregnated fibrous layer is 50% by mass or less, preferably 0.01 to 30% by mass, and more preferably 0.1 to 10% by mass.

[0102] The average thickness of each asphalt-impregnated fibrous layer may be 2 mm or less, for example, 0.1 to 2 mm, preferably 0.1 to 1.5 mm, further preferably 0.1 to 1 mm, even more preferably 0.1 to 0.5 mm, and most preferably 0.3 to 0.5 mm. If the average thickness of the asphalt-impregnated fibrous layer is too large, there is a risk that workability will decrease.

[0103] [Roof underlayment manufacturing method and usage method] The roof underlayment of the present invention can be manufactured by laminating each layer on both sides of an asphalt-impregnated fibrous layer. For example, the roof underlayment shown in Figure 1 may be manufactured by heating asphalt (third asphalt) to reduce its viscosity and then allowing it to penetrate into a fibrous structure (a fibrous structure for forming an asphalt-impregnated fibrous layer), followed by sequentially laminating a first asphalt waterproofing layer and a first uneven layer on one side of the asphalt-impregnated fibrous structure, and sequentially laminating a second asphalt waterproofing layer and a second uneven layer on the other side.

[0104] In producing the asphalt-impregnated fiber layer, the heating temperature for reducing the viscosity of the asphalt is, for example, 80 to 250°C, preferably 120 to 240°C, more preferably 150 to 200°C, and most preferably 160 to 180°C.

[0105] Examples of methods for impregnating the fiber structure with asphalt include a method in which the fiber structure is impregnated with asphalt using a coating roll or the like, and a method in which asphalt is applied to the surface of the fiber structure.

[0106] Asphalt application methods include conventional coating methods such as bar coating, spin coating, comma coating, die coating, and spray coating.

[0107] The method of laminating the first and second asphalt waterproofing layers on both sides of the asphalt-impregnated fibrous layer can be the same as the asphalt application method described above, which involves heating and applying the asphalt. In manufacturing the asphalt-impregnated fibrous layer, the amount of asphalt can be adjusted so that the first and second asphalt waterproofing layers are simultaneously formed using excess asphalt. Of these, the method of heating and applying the asphalt (first and second asphalt) to both sides of the asphalt-impregnated fibrous layer is preferred, as it allows for the easy manufacture of a roof underlayment that is both waterproof and easy to install.

[0108] The method for forming the uneven layer may be, for example, a method in which the first and second particles are scattered (laid or spread) approximately uniformly on the first and second asphalt waterproofing layers in a molten state, or a method in which the first and second asphalt waterproofing layers are heated, and then the first and second particles are scattered approximately uniformly and pressed together with a jig such as an iron bar to adhere them.

[0109] The form of the obtained roof underlayment can be selected depending on the purpose of use, and it may be used as a roll body in which a long waterproof sheet is wound into a roll, or the roof underlayment obtained by laminating each layer may be used as it is in sheet form without being rolled up.

[0110] The roof underlayment material of the present invention may be used by unwinding a roll of long roofing material on a roof and laying multiple sheets side by side on a roof underlayment with adjacent long ends overlapping each other. Furthermore, in the present invention, the overlapping ends may be more firmly fixed using conventional fasteners, if necessary. [Example]

[0111] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Details of the materials used in the examples and the methods for evaluating various properties are shown below.

[0112] [Roof underlayment materials] Base paper: "190R" manufactured by Koyo Sangyo Co., Ltd., basis weight 190g / m 2 Straight asphalt: Idemitsu Kosan Co., Ltd. "Straight Asphalt 60-80", penetration (25°C) 66 (1 / 10 mm), softening point 47°C Blown asphalt: Idemitsu Kosan Co., Ltd. "Blown Asphalt 10-20", penetration (25°C) 16 (1 / 10 mm), softening point 110°C, elongation (25°C) 2 cm, toluene soluble content 99.77% Calcium carbonate: Manufactured by Kochi Heavy Carbon Co., Ltd., passed through a 200-mesh sieve Glass foam A: "Foam G; OSG." manufactured by Otsubo GSI Co., Ltd., passed through a 0.6 mm sieve Glass foam B: "Bub Glass" manufactured by Murakami Kaimeido Co., Ltd., passed through a 150 μm mesh sieve Silica sand: "V8" silica sand manufactured by Mikawa Silica Co., Ltd., passed through a 150 μm sieve Waste glass: Passed through a 150 μm mesh sieve

[0113] [Softening point and penetration of asphalt] The softening point and penetration of asphalt were measured in accordance with JIS K 2207. The difference from the method described in JIS was that in tests at 55 to 80°C, the test specimens were left to stand for at least one hour together with the thermostatic water bath in a thermostatic bath set to the respective temperature before the test was conducted.

[0114] [Bulk density of inorganic particles] The bulk specific gravity of the inorganic particles was measured in accordance with JIS Z 2504:2020 using a funnel with an orifice diameter of 2.5 mm and a funnel angle of 60 degrees.

[0115] [Particle size range of inorganic particles] The particle size range of the inorganic particles was measured using a laser diffraction / scattering device ("Microtrac HRA9320" manufactured by Nikkiso Co., Ltd.).

[0116] [Average pore size of inorganic particles and amount of mercury intrusion] The average pore size and mercury intrusion amount of inorganic particles were measured in accordance with JIS R 1655 "Method for testing pore size distribution of molded fine ceramics by mercury intrusion method" using a mercury intrusion porosimeter (Quantachrome, Model PoreMaster-60) according to the following procedure.

[0117] First, 0.2 g of the test specimen was weighed and loaded into a 0.5 mL cell stem. Next, the amount of mercury intrusion was measured in a low-pressure chamber, and then the specimen was removed and measured again in a high-pressure chamber. From these measurement results, the value calculated by the software attached to the measuring device was used as the amount of mercury intrusion for the target test specimen.

[0118] [Specific surface area of ​​inorganic particles] The specific surface area of ​​inorganic particles was measured in accordance with JIS Z 8830 "Method for measuring the specific surface area of ​​powders (solids) by gas adsorption" using a specific surface area meter (Quantachrome Instruments' "NOVA 4200e"). 6.3 Measurement of adsorbed gas was performed based on 6.3.1 Static volume method, and 7.2 Analysis of adsorption data was performed based on the multipoint method.

[0119] [Temperature change test under exposure conditions] a) The room temperature was set to 35°C.

[0120] b) A stand was placed 700 mm away from the infrared irradiation stand, and the test specimen was attached to the stand at its edges with staples onto a 12 mm thick piece of plywood measuring 455 x 910 mm (placed so that the surface was irradiated with infrared rays).

[0121] c) A temperature sensor (T&D Corporation's "Ondotori Temperature Data Logger TR-71wf") was attached with aluminum tape to one location on the back of the test specimen, and then the edges of the test specimen were covered with aluminum tape and the temperature was measured.

[0122] d) The irradiation dose is 0.544kw / m 2 The specimen was then exposed to infrared light (illuminance: 1310 lux) for 30 minutes.

[0123] Example 1 An asphalt-impregnated fiber layer was prepared by impregnating the base paper with straight asphalt at a temperature of 180 to 200° C. The proportion of the straight asphalt was 100 parts by mass relative to 100 parts by mass of the base paper.

[0124] After impregnation, the mixture was applied to both sides of the asphalt-impregnated fiber layer using a coating roll at a temperature of 180°C so that the thickness of the first and second asphalt waterproofing layers (a mixture of blown asphalt and calcium carbonate (blown asphalt / calcium carbonate = 71% by mass / 29% by mass)) was 0.3 mm each, and the first and second asphalt waterproofing layers were laminated.

[0125] Both the front and back surfaces of the obtained laminate were heated on a hot plate set to 140°C, and then glass foam A was sprayed over the entire surface of both surfaces and pressed with an iron rod to adhere them, producing a test specimen (roof underlayment). The weight of the obtained test specimen was measured before and after spraying with glass foam A, and the amount of glass foam A sprayed on the surface (the amount that can be sprayed over the entire surface, meaning basis weight) was calculated. An electron microscope photograph of the glass foam A used is shown in Figure 2.

[0126] Example 2 A test specimen was prepared in the same manner as in Example 1, except that glass foam B was sprayed in place of glass foam A at the basis weight shown in Table 3.

[0127] Example 3 A test specimen was prepared in the same manner as in Example 1, except that silica sand was scattered on the surface of the laminate in the amount shown in Table 3, and glass foam A was scattered on the back surface in the amount shown in Table 3.

[0128] Example 4 A test specimen was prepared in the same manner as in Example 1, except that glass foam A was spread on the surface of the laminate in the amount shown in Table 3, and silica sand was spread on the back surface in the amount shown in Table 3.

[0129] Comparative Example 1 Test specimens were prepared in the same manner as in Example 1, except that silica sand was scattered in the amount shown in Table 3 instead of glass foam A.

[0130] Comparative Example 2 Test specimens were prepared in the same manner as in Example 1, except that waste glass was scattered in the amount shown in Table 3 instead of glass foam A.

[0131] In Examples 1 to 4 and Comparative Examples 1 and 2, the softening point and penetration at 25°C and 55 to 80°C of the mixtures of blown asphalt and calcium carbonate (asphalt compositions) used as the first and second asphalt waterproofing layers were measured. The results are shown in Table 1.

[0132] [Table 1]

[0133] As is clear from the results in Table 1, the penetration of the asphalt composition forming the waterproof layer increases rapidly when the temperature exceeds 75° C. and reaches 80° C. Therefore, at temperatures above 80° C., the asphalt softens, causing stickiness and reducing handleability.

[0134] The bulk density, particle size range, average pore size, mercury intrusion amount, and specific surface area of ​​the porous inorganic particles used in Examples 1 to 4 and Comparative Examples 1 and 2 were measured, and the results are shown in Table 2.

[0135] [Table 2]

[0136] As is clear from Table 2, glass foam has a lower bulk density than silica sand and waste glass, and is therefore lightweight.

[0137] Table 3 shows the results of a temperature change test carried out on the test specimens obtained in Examples 1 to 4 and Comparative Examples 1 and 2 under exposed conditions.

[0138] [Table 3]

[0139] As is clear from the results in Table 3, Examples 1 to 4, which contained glass foam, had lower back surface temperatures and greater heat insulating effects than Comparative Examples 1 and 2.

[0140] Comparing Examples 1 and 2, which are made of the same material, with Comparative Example 2, the foamed Example had a lower back surface temperature than Comparative Example 2. This is presumably because Examples 1 and 2 are foamed, while Comparative Example 2 is non-foamed and has a small specific surface area, so the insulating effect of the air layer is not effectively expressed.

[0141] Comparing Example 1 and Example 2, Example 1, which had a small average pore size and a large specific surface area, had a low back surface temperature, a high insulating effect, and a back surface temperature of less than 80°C, which was a temperature that was excellent in handleability and could also suppress the occurrence of stickiness. In Example 2, which had a large average pore size, it can be assumed that the molten asphalt composition penetrated into the pores and filled the voids, resulting in a decrease in the insulating effect.

[0142] Comparing Example 1 with Examples 3 and 4, Example 1 was able to exhibit a heat insulating effect with excellent handleability by using glass foam on both sides. [Industrial Applicability]

[0143] The roof underlayment material of the present invention can be used as a roof underlayment material for various buildings, for example, wooden buildings such as Japanese houses. [Explanation of symbols]

[0144] 1...Roof underlayment 2...First uneven layer 3...First asphalt waterproof layer 4...Asphalt-impregnated fiber layer 5...Second asphalt waterproof layer 6...Second uneven layer

Claims

1. A roof underlayment material that is laid on a roof substrate and has an uneven layer containing porous inorganic particles.

2. 2. The roof underlayment material according to claim 1, further comprising a waterproof layer containing asphalt, and the uneven layer is formed on at least one surface of the waterproof layer.

3. A roof underlayment material, wherein the uneven layer comprises a first uneven layer containing first particles and a second uneven layer containing second particles, The first uneven layer is disposed on the side that comes into contact with the roof underlayment; a first asphalt waterproofing layer laminated on the first uneven layer and formed of a first asphalt composition containing a first asphalt; an asphalt-impregnated fiber layer laminated on the first asphalt waterproofing layer and formed of a fiber structure containing a third asphalt; a second asphalt waterproofing layer laminated on the asphalt-impregnated fiber layer and formed of a second asphalt composition containing a second asphalt; The second uneven layer is laminated on the second asphalt waterproofing layer, and The roof underlayment of claim 1 , wherein at least one of the first particles and the second particles comprises porous inorganic particles.

4. 4. The roof underlayment of claim 3, wherein the first particles comprise first porous inorganic particles and the second particles comprise second porous inorganic particles.

5. The roof underlayment material according to any one of claims 1 to 3, wherein the porous inorganic particles are porous glass particles.

6. The roof underlayment material according to any one of claims 1 to 3, wherein the porous inorganic particles are glass foam.

7. The bulk density of the porous inorganic particles is 1.1 g / cm ３ The roof underlayment material according to any one of claims 1 to 3, wherein:

8. The specific surface area of ​​the porous inorganic particles is 0.35 m ２ The roof underlayment material according to any one of claims 1 to 3, wherein the tensile strength is 1 / g or more.

9. The roof underlayment material according to any one of claims 1 to 3, wherein the porous inorganic particles have an average pore size of 35 µm or less.

10. The roof underlayment material according to any one of claims 1 to 3, wherein the porous inorganic particles have an average pore size of 30 µm or less.

11. The roof underlayment material according to any one of claims 1 to 3, wherein the amount of mercury intrusion of the porous inorganic particles is 0.45 cc / g or more.

12. The roof underlayment material according to any one of claims 1 to 3, wherein the porous inorganic particles have an average particle size of 40 to 500 µm.

13. The porous inorganic particles have a basis weight of 200 g / m ２ The roof underlayment material according to any one of claims 1 to 3, wherein:

14. 4. The roof underlayment material according to claim 3, wherein the penetration of the first asphalt composition and the second asphalt composition is 50 or less at 25°C.

15. The roof underlayment material according to claim 3, wherein the first asphalt composition comprises 1 to 100 parts by weight of a first filler per 100 parts by weight of the first asphalt, and the second asphalt composition comprises 1 to 100 parts by weight of a second filler per 100 parts by weight of the second asphalt.

16. A method for improving the workability of roof underlayment by forming an uneven layer containing porous inorganic particles on at least one surface of a waterproof layer containing asphalt.

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