Rock wool heat insulation material and production method thereof

Abstract

To provide a technology allowing rock wool on a surface of rock wool heat insulation material to be hardly peeled off by external force and a technology allowing the rock wool on the surface of the rock wool heat insulation material to be hardly peeled off by the external force and capable of holding, in the rock wool heat insulation material, binder slurry configuring the rock wool heat insulation material upon formation of the rock wool heat insulation material.MEANS: A rock wool heat insulation material comprises: a substrate layer with absolute dry bulk density of a specific value or less having rock wool and binder slurry as main components; and a binder slurry material with solid content density within a specific range, covering a surface of the substrate layer.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a rock wool insulation material. In particular, the present invention relates to a rock wool insulation material whose surface is resistant to peeling due to external force. The present invention also relates to a method for manufacturing a rock wool insulation material. In particular, the present invention relates to a method for manufacturing a rock wool insulation material whose surface is resistant to peeling due to external force. [Background technology]

[0002] Architectural or civil engineering structures are constructed using materials such as steel, concrete, mortar, stone, brick, wood, tile, plaster, glass, and earth. However, structures constructed solely from these materials have high thermal conductivity and tend to lose heat easily, resulting in poor heating and cooling efficiency. For this reason, insulation materials are used. Widely used insulation materials include foamed resin insulation materials such as beaded polystyrene foam, extruded polystyrene foam, and rigid urethane foam. However, many of these materials are flammable, and fires have occurred both domestically and internationally due to the ignition of foamed resin insulation materials. Therefore, rock wool insulation made of non-flammable rock wool and a binder has been proposed as a thermal insulation material (see, for example, Patent Documents 1, 2, and 3). The binder used here is cement, synthetic resin, alkali silicate, blast furnace slag powder, or other inorganic powder containing SiO2.

[0003] Rock wool-based fire-resistant coating materials, which are made of a rock wool composition containing cement, rock wool, and water, are widely used as fire-resistant coating materials. Although these rock wool-based fire-resistant coating materials have excellent fire resistance, namely, they can suppress the temperature rise of the covered substrate for a certain period of time even when exposed to high temperatures during a fire, their thermal conductivity is higher than that of rock wool insulation materials, and their thermal insulation performance is insufficient. Rock wool insulation is designed to have a lower density than rock wool fire-resistant coating materials in order to enhance its insulating properties. As a result, rock wool insulation is weaker than rock wool fire-resistant coating materials, and there were concerns that the rock wool (granular rock wool cotton particles) on the surface would peel off due to wind pressure or external forces. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-193652 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-087479 [Patent Document 3] Japanese Patent Publication No. 2020-128307 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention aims to provide a technology that makes it difficult for rock wool on the surface of a rock wool insulation material to peel off due to external forces. More specifically, the present invention aims to provide a technology that makes it difficult for rock wool on the surface of a rock wool insulation material to peel off due to external forces and that can retain the binder slurry that constitutes the rock wool insulation material within the rock wool insulation material when the rock wool insulation material is formed. Another object of the present invention is to provide a rock wool insulation material in which the rock wool on the surface is resistant to peeling due to external forces. More specifically, an object of the present invention is to provide a rock wool insulation material in which the rock wool on the surface is resistant to peeling due to external forces and in which the binder slurry that constitutes the rock wool insulation material can be retained within the rock wool insulation material when the rock wool insulation material is formed. Another object of the present invention is to provide a method for manufacturing a rock wool insulation material that can produce a rock wool insulation material in which the rock wool on the surface is resistant to peeling due to external forces. More specifically, it is an object of the present invention to provide a method for manufacturing a rock wool insulation material in which the rock wool on the surface is resistant to peeling due to external forces and in which the binder slurry that constitutes the rock wool insulation material can be retained within the rock wool insulation material during formation. [Means for solving the problem]

[0006] As a result of intensive research into solving the above problems, the present inventors have found that the above problems can be solved by using a base layer containing rock wool and a binder slurry as the main components and having an oven-dry bulk density of a specific value or less, and covering the surface of the base layer with a binder slurry layer having a solid content within a specific range, and have completed the present invention. That is, the present invention is a method for producing a rock wool insulation material as shown in the following (1) to (3) and (4). (1) A bulk density of 0.25 g / cm3, consisting primarily of rock wool and binder slurry 3 A rock wool insulation material comprising the following base layer and a binder slurry layer made of a binder slurry having a solid content of 25 to 60 mass%, the binder slurry layer covering the surface of the base layer. (2) The rock wool heat insulating material according to (1) above, characterized in that the binder slurry forming the base layer does not contain cement as a main component. (3) The rock wool heat insulating material according to (1) or (2) above, characterized in that the binder slurry forming the binder slurry layer contains cement as a main component. (4) Rock wool and binder slurry as the main components, with a bone dry bulk density of 0.25 g / cm 3 A method for producing a rock wool insulation material, comprising forming the following base layer and covering the surface of the base layer with a binder slurry layer made of a binder slurry having a solid content of 25 to 60 mass%. [Effects of the Invention]

[0007] According to the present invention, a rock wool insulation material is obtained in which the rock wool on the surface is resistant to peeling due to external forces. According to the present invention, a rock wool insulation material is obtained in which the rock wool on the surface of the rock wool insulation is resistant to peeling due to external forces and in which the binder slurry that constitutes the rock wool insulation can be held within the rock wool insulation when the rock wool insulation is formed. Furthermore, according to the present invention, a manufacturing method for a rock wool insulation material is obtained in which the rock wool on the surface is resistant to peeling due to external forces. Furthermore, according to the present invention, a manufacturing method for a rock wool insulation material is obtained in which the rock wool on the surface is resistant to peeling due to external forces and in which the binder slurry that constitutes the rock wool insulation can be held within the rock wool insulation when the rock wool insulation is formed. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram of an example of a spraying device used in the present invention. [Figure 2] FIG. 2 shows photographs of a rock wool thermal insulation specimen and a peeled sample before and after the test in Test No. 1, which is a test for evaluating surface hardness in the examples. [Figure 3] FIG. 3 is a photograph of a rock wool thermal insulation specimen and a peeled sample before and after the test in the surface hardness evaluation test No. 2 in the examples. [Figure 4] FIG. 4 shows photographs of a rock wool thermal insulation specimen and a peeled sample before and after the test in Test No. 3, which is a test for evaluating surface hardness in the examples. DETAILED DESCRIPTION OF THE INVENTION

[0009] The rock wool thermal insulation material of the present invention is composed mainly of rock wool and binder slurry and has an oven-dry bulk density of 0.25 g / cm 3The laminated ...

[0010] The rock wool in the present invention refers to a material (mineral fiber) formed by rapidly cooling a material primarily composed of rock or blast furnace slag melted in a melting furnace. For example, it also includes slag wool produced from a material primarily composed of blast furnace slag. The rock wool used in the present invention is preferably agglomerated (granular, fiber agglomerates with a diameter of several mm to several cm) like the granular rock wool used in rock wool-based fire-resistant coating materials, because the resulting rock wool composition layer has low thermal conductivity and is excellent at retaining the shape of the resulting substrate layer. The rock wool aggregate is preferably a granular cotton obtained by subjecting raw cotton consisting of fiberized mineral fibers to one or a combination of two or more processes, such as crushing, deflocculating, cutting, sorting (e.g., sieving), and granulation. Examples of the rock wool granular cotton include fine and micro-sized rock wool granules, and commercially available rock wool granules, fine and micro-sized rock wool granules, such as "S-Fiber Granular Cotton" (product name) manufactured by Japan Rock Wool Co., Ltd., "Locceram Granular Cotton" (product name) manufactured by JFE Rock Fiber Corporation, and "Pacific Mineral Fiber Granular Cotton" (product name) manufactured by Pacific Materials Corporation, can be suitably used. When such rock wool granular cotton is used, heat is less likely to be transmitted to the substrate covering the rock wool, providing thermal insulation, fire resistance, or non-combustibility, as well as sound absorption.

[0011] The binder slurry forming the base layer in the present invention (hereinafter sometimes referred to as "base layer binder slurry") is a slurry primarily composed of water and one or more binders selected from cements such as Portland cement and white cement, inorganic binders such as alkali silicates and latent hydraulic substances such as blast furnace slag powder, and organic binders composed of polymers (synthetic resins) such as vinyl acetate resins, acrylic resins, and synthetic rubber. The binder slurry may also contain one or more additives (admixtures) within the scope of the present invention. Examples of additives (admixtures) include thickeners, cement dispersants, expansive additives, waterproofing agents, rust inhibitors, shrinkage-reducing agents, pigments, fibers other than rock wool, water repellents, efflorescence inhibitors, quick-setting additives, hardening additives, retarders, foaming agents, antifoaming agents, gypsum, pozzolans such as silica fume and fly ash, water repellents, and surface hardeners. It is preferable that the binder slurry for the base layer does not contain cement as a main component, as this reduces CO2 emissions and leads to carbon neutrality. Here, "does not contain cement as a main component" means that the cement content of the binder slurry for the base layer is 10% by mass or less, more preferably 5% by mass or less, even more preferably 1% by mass or less, and most preferably does not contain cement.

[0012] In the present invention, the base layer has an oven-dry bulk density of 0.25 g / cm 3 Here, the bone dry bulk density is determined by calculating the volume (V) of the specimen from the outer dimensions of the base layer specimen obtained by cutting out a cylindrical shape from the formed base layer using a rock wool cutter with an inner diameter of 80 mm, placing the specimen in a dryer and drying at 105°C until it reaches a constant weight, and then calculating the bulk density (ρ) from the mass (M) of the specimen after drying using the following formula (1), which is used as the bone dry bulk density. ρ=M / V (1)

[0013] The base layer has an oven-dry bulk density of 0.25 g / cm 3 If the density exceeds 0.05 to 0.22 g / cm, the thermal conductivity is higher than that of rock wool insulation and the thermal insulation performance is insufficient. 3is preferable, and 0.10 to 0.20 g / cm 3 is preferred.

[0014] The binder slurry forming the binder slurry layer in this invention (hereinafter sometimes referred to as "finishing binder slurry"), like the binder slurry for the base layer, is a slurry primarily composed of water and one or more binders selected from cements such as Portland cement and white cement, inorganic binders such as alkali silicates and latent hydraulic substances such as blast furnace slag powder, and organic binders composed of polymers such as vinyl acetate resins, acrylic resins, and synthetic rubbers. It may also contain one or more admixtures, as long as the effects of this invention are not impaired. Examples of such admixtures include thickeners, cement dispersants, expansive additives, waterproofing agents, rust inhibitors, shrinkage-reducing agents, pigments, fibers other than rock wool, water repellents, efflorescence inhibitors, quick-setting additives, quick-hardening additives, retarders, foaming agents, defoamers, gypsum, pozzolans such as silica fume and fly ash, water repellents, and surface hardeners. The binder slurry for the surface layer may be the same as the binder slurry for the base layer. The finishing binder slurry preferably contains cement as a main component, that is, the cement content in the binder of the finishing binder slurry is preferably 10% by mass or more, because this increases the strength of the binder slurry layer (finishing layer). The cement content in the binder of the finishing binder slurry is more preferably 50% by mass or more, even more preferably 70% by mass or more, and most preferably 90% by mass or more.

[0015] The finishing binder slurry of the present invention has a solid content of 25 to 60% by mass. That is, the solid content is 25 to 60 parts by mass per 100 parts by mass of the binder slurry. If the solid content is less than 25% by mass, when the finishing binder slurry is applied (disposed) so as to fully cover the surface of the base layer, the base layer may not be able to fully retain the finishing binder slurry. If the solid content exceeds 65% by mass, it is difficult to form a binder slurry layer on the surface of the base layer using a spraying device used to form a rock wool-based fire-resistant coating material. Furthermore, the base layer and the binder slurry layer are difficult to integrate, and there is a risk of peeling. The finishing binder slurry of the present invention preferably has a solid content of 25 to 55% by mass, and more preferably 25 to 50% by mass.

[0016] The method for producing rock wool insulation of the present invention is to produce a thermal insulating material having an absolute dry bulk density of 0.25 g / cm3, which is mainly composed of rock wool and binder slurry. 3 The method is characterized in that the following base layer is formed, and the surface of the base layer is coated with a binder slurry layer made of a binder slurry having a solid content of 25 to 60 mass%. The rock wool and binder slurry that form the base layer, and the binder slurry that forms the binder slurry layer, are the rock wool, base layer binder slurry, and finishing binder slurry, respectively. Furthermore, a third layer may be formed on the surface of the binder slurry layer for the purpose of improving design, light resistance, weather resistance, water repellency, mildew resistance, etc.

[0017] In the present invention, the base layer and binder slurry layer can be suitably formed using a spraying device such as the spraying device used in the semi-dry construction method used in the rock wool spraying method, an example of which is shown in a schematic diagram in Figure 1. The base layer can also be formed by mixing the base layer binder slurry with granular fibers and then filling a formwork or applying it to a substrate with a trowel, roller, or the like. Examples of substrates used in forming the base layer include concrete, mortar, steel, and wood. The binder slurry layer can also be formed by filling a formwork installed on the surface of the base layer or on the substrate layer with a finishing binder slurry, or by applying it to the surface of the base layer with a trowel, roller, or the like. The third layer can be formed by applying it to the surface of the binder slurry layer with a trowel, roller, or spraying device, or the like.

[0018] An example of a spraying device used in a semi-dry construction method that is suitably used in the rock wool spraying method that can be used in the present invention is shown in a schematic diagram in Figure 1, and is a spraying device 10 whose main components are a cotton opener 20, a blower (air blower) 14, a rock wool pressure-feeding hose 9, a binder slurry storage tank 8, a binder slurry pressure-feeding pump 7, a binder slurry pressure-feeding hose 6, and a spraying gun 1. Rock wool (granular cotton) 11 is fed into a hopper 23 of the cotton opener 20, and after being loosened in a first cotton opener section 21 of the cotton opener 20, is sent by a screw feeder 24 to a second cotton opener section 22 where it is further loosened. The loosened rock wool enters a rotary feeder (quantitative supply device) 25 and is supplied in a fixed amount to a rock wool pressure-feeding pipe 26. The loosened rock wool 5 sent to the rock wool pressure pipe 26 is pressure-fed to a rock wool pressure-fed hose 9 connected to the rock wool pressure-fed pipe 26 by air sent from a blower (air blower) 14 connected to the rock wool pressure-fed pipe 26, and is sprayed from a rock wool nozzle 2 of a spray gun 1 connected to the tip of the rock wool pressure-fed hose 9.

[0019] The produced binder slurry 4 (binder slurry for base layer) is stored in binder slurry storage tank 8, and binder slurry pressure pump 7 pressure-feeds the binder slurry 4 through binder slurry suction hose 15, binder slurry pressure pump 7, and binder slurry pressure-feed hose 6 to binder slurry nozzle 3 of spray gun 1, where it is sprayed from binder slurry nozzle 3. Granular rock wool 5 sprayed from rock wool nozzle 2 of spray gun 1 and binder slurry 4 sprayed from binder slurry nozzle 3 of spray gun 1 are mixed together at the tip of spray gun 1, and a base layer (rock wool composition layer) composed mainly of rock wool and binder slurry is formed. The binder slurry layer is preferably formed using the same equipment as the base layer. In this case, rock wool is not pumped, and instead, the binder slurry for the base layer is not used as the binder slurry 4, but rather the finishing binder slurry is used as the binder slurry 4, which is sprayed onto the base surface from the binder slurry nozzle 3 of the spray gun 1. The binder slurry layer may be formed by a spraying method using a different spraying device (e.g., a mortar spraying device or a paint spraying device is preferred) instead of the spraying device 10 used in the semi-dry construction method. As described above, the binder slurry layer may also be formed by filling a formwork installed on the surface of the base layer or the base of the base layer with the finishing binder slurry, or by applying it to the surface of the base layer with a trowel or roller. A third layer may also be formed on the surface of the binder slurry layer to enhance design, light resistance, weather resistance, water repellency, or mildew resistance. The third layer can be formed by applying the binder slurry layer surface with a trowel, roller, sprayer, or the like, depending on the properties of the material that constitutes the third layer. [Example]

[0020] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples in any way.

[0021] [Example 1] <Formation of base layer> Rock wool insulation using the inorganic binder (base layer binder slurry) of Test No. 11 described in Table 1 of JP 2022-031022 A and rock wool granular cotton was sprayed into a polypropylene container (each corner of the opening (178 mm x 124 mm) is arc-shaped) measuring 178 mm wide x 124 mm deep x 30 mm deep using a spraying device used in the semi-dry method used in the rock wool spraying method, as shown in the schematic diagram of an example in Figure 1. The surface was smoothed with a trowel to form a base layer. The materials used are shown below. Rockwool: Rockwool granules manufactured by Pacific Materials Alkali silicate: No. 3 water glass (SiO2: 29.03 mass%, Na2O: 9.47 mass%, H2O: 61.50 mass%) SiO2-containing inorganic powder other than cement and alkali silicate: Blast furnace slag powder (ground blast furnace slag 4000, Blaine specific surface area: 4130 cm 2 / g) Water: Water supply from Sakura City, Chiba Prefecture

[0022] <Formation of binder slurry layer> A cement slurry (finishing binder slurry) was prepared by mixing 100 parts by mass of cement with 200 parts by mass of water in a mixer. The prepared cement slurry was applied to the surface of the base layer in the polypropylene container in an amount of 2000 g / m. 2 A binder slurry layer was formed by applying the amount of coating using the spraying equipment used to form the base layer, and a rock wool insulation specimen was prepared (Test No. 1). The materials used were ordinary Portland cement manufactured by Taiheiyo Cement Corporation and waterworks from Sakura City, Chiba Prefecture.

[0023] <Evaluation test> As an evaluation test of the produced rock wool insulation material, the thermal conductivity and surface hardness were measured and evaluated. Thermal conductivity evaluation The same materials as the rock wool insulation specimens were sprayed onto plywood using the same spraying equipment to form a base layer of rock wool insulation. Test specimens measuring 200mm long x 200mm wide x 300mm high were cut from this rock wool insulation base layer to prepare thermal conductivity measurement specimens. Thermal conductivity was measured according to JIS A 1412-2, "Methods for measuring thermal resistance and thermal conductivity of thermal insulation materials - Part 2: Heat flow meter method." Thermal conductivity of 0.048 W / (m·K) or less was rated "excellent" (symbol: ○), and thermal conductivity of more than 0.048 W / (m·K) was rated "poor" (symbol: ×). Surface hardness evaluation The rock wool insulation specimens were cured indoors at 20°C and a relative humidity of 60% until they reached an age of 28 days. After curing, the surface of the rock wool insulation specimen (178 mm x 124 mm) was brushed with a brush for 1 minute, the mass of the peeled specimen was measured, and the proportion of the peeled specimen (peeling rate (mass%)) was calculated from the mass of the specimen before the test (mass of the rock wool insulation excluding the mass of the container).

[0024] The results of the evaluation test are shown in Table 1, along with the base layer composition and bone-dry bulk density, as well as the composition and application amount of the finishing binder slurry. In Table 1, RW, S, and W represent the mass of rock wool, the solid content of each slurry, and the water content of each slurry, respectively. "S / RW" in Table 1 represents the mass ratio of the solid content in the base layer binder slurry to the mass of rock wool. "W / RW" in Table 1 represents the mass ratio of the water in the base layer binder slurry to the mass of rock wool. "W / (S+RW)" in Table 1 represents the mass ratio of the water in the base layer binder slurry to the total mass of the rock wool and the solid content in the base layer binder slurry. Also, "S / (S+W)" in Table 1 represents the ratio of the solid content (cement) in the finishing binder slurry to the total solid content (cement) and water in the finishing binder slurry, i.e., the solid content (cement) concentration (mass % concentration) in the finishing binder slurry.

[0025] [Table 1]

[0026] A test specimen was prepared using the same base layer as in Test No. 1, but without a binder slurry layer. The thermal conductivity and surface hardness were measured and evaluated in the same manner as in Test No. 1 (Test No. 2). The results, along with the base layer composition and bone-dry bulk density, are shown in Table 1. A test specimen was also prepared using a composition equivalent to that of the rock wool fireproof coating material, but without a binder slurry layer, as in Test No. 2. The thermal conductivity and surface hardness were measured and evaluated in the same manner as in Test No. 1 and Test No. 2 (Test No. 3). The results, along with the base layer composition and bone-dry bulk density, are shown in Table 1. Photographs of the rock wool insulation test specimens and the peeled specimens before and after the surface hardness evaluation tests for Test Nos. 1 to 3 are shown in Figures 2 to 4. (a) in each figure is a photograph of the rock wool insulation test specimen before the test, (b) is a photograph of the rock wool insulation test specimen after the test, and (c) is a photograph of the peeled specimen.

[0027] [Example 2] The same rock wool insulation material as that used to form the base layer in Test No. 1 of Example 1 was sprayed onto the underside of a plywood board that was placed horizontally to resemble a ceiling surface using a spraying device used in the semi-dry method used in the rock wool spraying method, to form a base layer 30 mm thick. A cement slurry (finishing binder slurry) was prepared with the blending ratio shown in Table 2 and applied to the surface (lower surface) of the base layer made of the prepared rock wool thermal insulation material in the amount shown in Table 2. In each case, the amount applied was 600 g / m2, calculated as the solid content (cement) of the cement slurry. 2 The workability and water retention properties were evaluated when the cement slurry was applied to the surface of the base layer. The results of the workability and water retention evaluation are shown in Table 2. -Evaluation of workability When the spraying equipment used in the semi-dry construction method was used, if the pressure of the slurry pressure pump was below the allowable pressure (1.0 MPa) and spraying could be performed without clogging in the slurry pressure hose, etc., it was evaluated as "good" (symbol: ○), and if the pressure of the slurry pressure pump exceeded the allowable pressure or if clogging occurred in the slurry pressure hose, etc., it was evaluated as "poor" (symbol: ×). Water retention evaluation The water retention was evaluated based on whether the cement slurry sprayed onto the base layer could be retained by the base layer. When the cement slurry was retained by the base layer and did not drip from the base layer, it was evaluated as "good" (symbol: ○), and when the cement slurry dripped from the base layer, it was evaluated as "poor" (symbol: ×).

[0028] [Table 2]

[0029] The rock wool insulation material of Test No. 1, which corresponds to an example of the present invention, had excellent surface hardness and a very small peeling rate. Furthermore, the rock wool insulation materials of Test Nos. 4 to 6, which correspond to examples of the present invention, were easy to apply when formed and also had excellent water retention properties. [Industrial Applicability]

[0030] The present invention can be suitably applied to coating the surface of components of structures or constructions made of concrete, steel, wood, etc., for the purpose of imparting heat insulation to the components, and can also be suitably applied to filling the interior of the components. [Explanation of symbols]

[0031] 1 Spray gun (center gun) 2 Granular rock wool nozzle 3. Binder slurry injection nozzle 4. Binder Slurry 5. Disintegrated granular rock wool 6. Binder slurry pressure feed hose 7. Pressure pump for binder slurry 8. Storage tank for binder slurry 9 Granular rock wool pressure feed hose 10 Spraying equipment (spraying system) 11 Granular rock wool (granular rock wool cotton) 12. A fibrous layer consisting of a confluent mixture of granular rock wool and binder slurry. 13 Base (wall) 14 Blower 15 Suction hose for binder slurry 20 Cotton opening machine 21 First Cotton Decomposition Department 22 Second cotton opening section 23 Hopper 24 Screw feeder 25 Rotary feeder (quantitative feeder) 26 Granular rock wool pressure pipe 31 Binder slurry pipeline 32 Granular rock wool pipeline 33 Central axis of granular rock wool pipe

Claims

1. The main components are rock wool and binder slurry, and the bone dry bulk density is 0.25 g / cm ３ A rock wool insulation material characterized by comprising the following base material layer and a surface of the base material layer covered with a binder slurry layer made of a binder slurry having a solid content of 25 to 60 mass%.

2. 2. The rock wool heat insulating material according to claim 1, wherein the binder slurry forming the base layer does not contain cement as a main component.

3. 3. The rock wool heat insulating material according to claim 1, wherein the binder slurry forming the binder slurry layer contains cement as a main component.

4. The main components are rock wool and binder slurry, and the bone dry bulk density is 0.25 g / cm ３ A method for producing a rock wool insulation material, comprising forming the following base layer and covering the surface of the base layer with a binder slurry layer made of a binder slurry having a solid content of 25 to 60 mass%.

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