Abstract: Disclosed is a dry gypsum composition containing hemihydrate gypsum, at least one pigment and a crystal habit modifier. The crystal habit modifier is at least one compound selected from the group consisting of sulfate salts, carboxylate salts, carbonate salts and inorganic chlorides, and a content of the at least one compound is in a range of 0.1 to 5 parts by mass per 100 parts by mass of the hemihydrate gypsum, whereby upon hydration of the hemihydrate gypsum into dihydrate gypsum, the dihydrate gypsum is controlled to become plate crystals having an aspect ratio of 1 to 9. A gypsum-based coating formulation making use of the dry gypsum composition is also disclosed.

Abstract: The present invention provides an apparatus and a method for fractionating gypsum slurry which can surely control the density of the gypsum slurry fractionated from the mixer (fractionated slurry), which can restrict change of the flow rate of the fractionated slurry, and which can reduce the consumption of foam or foaming agent. The fractionation apparatus (30) fractionates the gypsum slurry from a mixer (4) for mixing calcined gypsum and water. The mixer has a hollow connector section (50), which allows the gypsum slurry to flow from a mixing area inside of the mixer into a chute section (5), and the chute section (5) discharging the inflow of gypsum slurry through its slurry discharge port onto a gypsum board liner paper. The fractionation apparatus has a slurry fractionation port (33) opening to the chute section or the hollow connector section, and causes a part of the gypsum slurry in the chute or hollow connector section to be delivered to a slurry delivery conduit (11,13,19).

Abstract: A joint filler composition may include 100 parts by mass of a base material, 1 to 20 parts by mass of inorganic hollow particles, and 3 to 20 parts by mass of a mineral having a chain structure or a layer structure.

Abstract: Disclosed is a process for the continuous modification of dihydrate gypsum. The process includes a hemihydration step of calcining the dihydrate gypsum as a raw material into hemihydrate gypsum and a recrystallization step of hydrating and recrystallizing the hemihydrate gypsum in an aqueous slurry to convert the hemihydrate gypsum into modified dihydrate gypsum of a crystalline form different from the dihydrate gypsum as the raw material.

Abstract: Disclosed is a dry gypsum composition containing hemihydrate gypsum, at least one pigment and a crystal habit modifier. The crystal habit modifier is at least one compound selected from the group consisting of sulfate salts, carboxylate salts, carbonate salts and inorganic chlorides, and a content of the at least one compound is in a range of 0.1 to 5 parts by mass per 100 parts by mass of the hemihydrate gypsum, whereby upon hydration of the hemihydrate gypsum into dihydrate gypsum, the dihydrate gypsum is controlled to become plate crystals having an aspect ratio of 1 to 9. A gypsum-based coating formulation making use of the dry gypsum composition is also disclosed.

Abstract: A gypsum board forming device (10) constitutes an apparatus of producing gypsum boards. A layered formation of a lower sheet (1), an upper sheet (2) and a gypsum slurry (6) passes through a forming gate (40). The forming device forms the formation into a plate-like configuration with use of upper and lower plates (20, 30). The upper plate (20) is constituted from a fixed substrate plate (21) and a movable plate (22), and the movable plate is in surface-to-surface contact with the upper sheet of the layered formation. A plurality of actuators (50) is supported by the substrate plate. Each of the actuators applies an upward or downward load (P) to the movable plate locally for a local deformation of the movable plate owing to a deflection thereof. A gate size (T) is locally changed by displacement of the movable plate relative to the substrate plate.

Abstract: A joint filler composition may include 100 parts by mass of a base material, 1 to 20 parts by mass of inorganic hollow particles, and 3 to 20 parts by mass of a mineral having a chain structure or a layer structure.

Abstract: Labor saving and automatization of cleaning work of a conveyance face for articles or materials are intended to reliably and quickly execute the cleaning work. A cleaning apparatus has a cleaning implement (10) located on the upper side of a conveyance element (R). The cleaning implement includes a cleaning face (11) to be in contact with a conveyance face (S). The cleaning apparatus also has a traction device (6,7) which applies a tractive force (T) to the cleaning implement, in a direction (E) opposite to a conveyance direction (D) of a conveyance passage. The cleaning implement has a weight (P) for keeping the cleaning face in contact with the conveyance element in operation of the conveyor device, and cleans the conveyance face by means of contact and separation of the cleaning face and the conveyance face, and relative displacement therebetween (V1, V2, V3).

Abstract: There are provided a method of recovering a base paper for gypsum board for continuously and efficiently recovering a base paper for gypsum board from a waste material of gypsum board including a gypsum core and the base paper for gypsum board adhering thereto. The method of recovering a base paper for gypsum board includes steps of breaking the waste material of gypsum board, separating a gypsum component and a paper piece of the base paper for gypsum board from the broken waste material of gypsum board, and washing the separated paper piece with water using a rotary drum-type washing device so as to eliminate a gypsum component adhering to the paper piece.

Abstract: There are provided a method of recovering a base paper for gypsum board for continuously and efficiently recovering a base paper for gypsum board from a waste material of gypsum board including a gypsum core and the base paper for gypsum board adhering thereto. The method of recovering a base paper for gypsum board includes steps of breaking the waste material of gypsum board, separating a gypsum component and a paper piece of the base paper for gypsum board from the broken waste material of gypsum board, and washing the separated paper piece with water using a rotary drum-type washing device so as to eliminate a gypsum component adhering to the paper piece.

Abstract: Disclosed is a process for the continuous modification of dihydrate gypsum. The process includes a hemihydration step of calcining the dihydrate gypsum as a raw material into hemihydrate gypsum and a recrystallization step of hydrating and recrystallizing the hemihydrate gypsum in an aqueous slurry to convert the hemihydrate gypsum into modified dihydrate gypsum of a crystalline form different from the dihydrate gypsum as the raw material.

Abstract: High odor eliminating property is provided to a building material for interiors by compounding a hydrazide compound. Additionally, the odor eliminating property of the building material for interiors is improved and hygroscopicity and size stability at the time of use are provided by adding and compounding an organic carbide, an inorganic hygroscopic material, and a water repellent. Also, an interior structure in which these building materials for interiors are employed is provided.

Abstract: Provided is a method of manufacturing a weight-saved foamed gypsum board having a gypsum core with high strength and excellent adhesion properties of the gypsum core with base papers for gypsum board, which method is capable of adjusting the sizes of pores in a gypsum core of a weight-saved gypsum board product into a desired range in a short time and at a low cost, even if the kinds and the compounding ratios of gypsum raw materials vary.

Abstract: A gypsum board having mold resistance includes a gypsum core containing a first anti-mold agent poorly soluble in water and a waterproofing agent; and gypsum board paper containing a second anti-mold agent poorly soluble in water.

Abstract: The present invention provides a mixer and a mixing method which enable stable supply of slurry at a high flow rate with foam being uniformly mixed therein, and which enable reduction in consumption of foam to be fed to the slurry. The mixer (10) has a housing (20), a rotary disc (32), a slurry outlet port (45), a slurry delivery conduit (46) and a hollow connector section (47). A foam feeding port (41) is disposed in a predetermined position of an annular wall or the hollow connector section. The foam feeding port feeds the foam to the slurry, immediately before the slurry enters the slurry outlet port, or feeds the foam to the slurry in the hollow connector section. The slurry and the foam mix with each other at the slurry outlet port or on its downstream side. The foam is not substantially subjected to agitation impact of the mixer and a quantity of loss of the foam is reduced.

Abstract: A plaster board including a plaster core having a front surface, a back surface, two opposite side surfaces and two opposite end surfaces and a covering base paper covering the front surface, back surface, and two opposite side surfaces, which core includes high-density hard edge parts including the two opposite side surfaces, at least one high-density part including the front or back surface, and having a density substantially equal to densities of the high-density hard edge parts, and a central low-density part having a density less than the densities of the high-density hard edge parts and the high-density part and being inscribed in the high-density hard edge parts and the high-density part, wherein each of the high-density hard edge parts is formed so as not to be present in the nailing area along longitudinal directions of the board in which a nail for fixing the board is driven.

Abstract: There is provided a lightweight plaster board having a cellular porous plaster core, excellent in adhesion to a covering base paper for a plaster board, free from dry-out in side edge parts of the plaster board, and with no disadvantage in workability for driving a nail into the plaster board. The plaster board includes a plaster core having a front surface, a back surface, and four side surfaces, and at least one covering base paper that covers the front surface, the back surface, and the at least two opposite side surfaces of the plaster core.

Abstract: The invention provides a whetstone type of scoring device for production of gypsum boards which can accurately and stably form a groove of a constant depth on a sheet of paper for gypsum board liner, and which can prevent wear of a rotary blade and a backing block. The scoring device (11) for a gypsum board production machine (10) has the rotary blade (24) and the backing block (30). The sheet (3) travels under tension over the block (30), which abuts against the lower surface of the sheet. The block has an opening (32) immediately under the blade. The lower surface of the sheet is released downward by the opening. The sheet is ground by a blade edge (24a) while being slightly bent downward within a range of the opening (within an intimate contact area of an angle ?).

Abstract: Perforations of a board for building material are formed by a number of recesses (13), or a number of recesses (13) and through-holes (12). A bottom face (16) of the recess forms a face for screwing or driving the fixing element (70) thereto. A color of the bottom face is set to have a brightness of color decreased in comparison with a color of a surface (18) of the board. A substrate of the board is a gypsum board and the bottom face of the recess is formed by a liner paper for gypsum board. According to such a board, a region for screwing or driving the fixing element thereto can be ensured without impairing regularity, uniformity or architectural design of the perforations, and putty finishing or the like for an exposed part of the fixing element can be omitted.

Abstract: High odor eliminating property is provided to a building material for interiors by compounding a hydrazide compound. Additionally, the odor eliminating property of the building material for interiors is improved and hygroscopicity and size stability at the time of use are provided by adding and compounding an organic carbide, an inorganic hygroscopic material, and a water repellent. Also, an interior structure in which these building materials for interiors are employed is provided.