Abstract: A gypsum hardened body including a gypsum slurry that has been hardened is provided. The gypsum slurry is obtained by mixing calcined gypsum, calcium hydrogen phosphate dihydrate, water, and foam. The specific gravity of the gypsum hardened body is greater than or equal to 0.3 and less than or equal to 0.8.

Abstract: The object of the present invention is to provide an embedding material composition for casting that makes it possible to conduct a favorable casting in the case where casting is conducted using a resin pattern that is different from a conventional wax pattern in disappearance temperature and disappearance behaviors through “rapid heating” excellent in treatment efficiency. The present invention relates to an embedding material composition for casting not using a heat-expandable refractory material as a main component, comprising: a binder; and a non-heat-expandable refractory material having an average particle diameter of 5 to 20 ?m as main components, in which a content of the binder is 25 to 40 parts by mass and a content of the non-heat-expandable refractory material is 60 to 75 parts by mass in the case where the total amount of the main components is 100 parts by mass, and the present invention also relates to a casting process using the embedding material composition for casting.

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: A light emission part projects a laser light toward an edge portion of a formation. The laser light extends in a direction intersecting a conveyance direction of a forming belt. A light receiving part is opposed to the light emission part and located on the opposite side of the formation. The laser light passes through an area above an upper surface of the formation at least partially and is partially blocked by rising of the edge portion of the formation. A control device determines occurrence of the glue-joint failure on the basis of whether the quantity of light received by the light receiving part is reduced by at least a predetermined value or a predetermined rate, and provides or gives a visual display or a warning of the occurrence of glue-joint failure.

Abstract: The object of the present invention is to provide an embedding material composition for casting that makes it possible to conduct a favorable casting in the case where casting is conducted using a resin pattern that is different from a conventional wax pattern in disappearance temperature and disappearance behaviors through “rapid heating” excellent in treatment efficiency. The present invention relates to an embedding material composition for casting not using a heat-expandable refractory material as a main component, comprising: a binder; and a non-heat-expandable refractory material having an average particle diameter of 5 to 20 ?m as main components, in which a content of the binder is 25 to 40 parts by mass and a content of the non-heat-expandable refractory material is 60 to 75 parts by mass in the case where the total amount of the main components is 100 parts by mass, and the present invention also relates to a casting process using the embedding material composition for casting.

Abstract: Provided is a coloring agent composition to be added to a gypsum-containing raw material powder constituting a gypsum product and to be used for coloring the gypsum product, the coloring agent composition being a powder containing a pigment, calcined gypsum, and amorphous silica. A process for producing the coloring agent composition includes a first step of mixing a pigment, calcined gypsum, and amorphous silica to obtain a mixed powder. Use of the coloring agent composition makes it possible to easily produce gypsum products such as a powder and a hardened body that are excellent in colorability.

Abstract: [Object] Behavior of a flow of foam or foaming agent ejected to a gypsum slurry can be stabilized, and a relatively large amount of foam or foaming agent can be homogeneously or uniformly dispersed in the slurry. [Solution] A mixer (10) has a mixing area (10a) for preparing gypsum slurry (3), a slurry delivery section (4) for delivering the slurry from the mixing area, and a feeding port (60) for feeding foam (M) or a foaming agent to the slurry in the mixing area and/or the slurry delivery section under pressure. The slurry having the foam mixed therein is supplied to a production line (1) for forming gypsum boards or gypsum-based boards. The feeding port is provided with a partition member (62,64,65) dividing an ejecting region (61,61?). The ejecting region is divided into a plurality of openings (63), which simultaneously eject the foam or forming agent to the slurry.

Abstract: A gypsum slurry includes calcined gypsum, urea phosphate esterified starch, organopolysiloxane, and water.

Abstract: A process for the continuous modification of dihydrate gypsum includes calcining dihydrate gypsum into hemihydrate gypsum and recrystallizing the hemihydrate gypsum in an aqueous slurry to convert the hemihydrate gypsum into modified dihydrate gypsum of different crystalline form. The aqueous slurry in a recrystallization reaction tank is maintained at a constant temperature under stirring, and a feed rate of the hemihydrate gypsum to the recrystallization reaction tank and a discharge rate of the recrystallized dihydrate gypsum are controlled to substantially equal. Dihydrate gypsum as a starting raw material can be converted into high-purity, modified dihydrate gypsum of large crystals by recrystallizing the starting dihydrate gypsum after it is once calcined into hemihydrate gypsum.

Abstract: There is provided a gypsum dispersant and a gypsum additive that improve the fluidity of gypsum slurry even if gypsum raw materials used are different in quality and that do not induce delay of curing of gypsum slurry. A gypsum dispersant, including: (A) a polycarboxylic acid polymer; and (B) a polymer obtained by a reaction of an alkylene diamine and/or a monoamine and an epihalohydrin as essential components.

Abstract: A light emission part projects a laser light toward an edge portion of a formation. The laser light extends in a direction intersecting a conveyance direction of a forming belt. A light receiving part is opposed to the light emission part and located on the opposite side of the formation. The laser light passes through an area above an upper surface of the formation at least partially and is partially blocked by rising of the edge portion of the formation. A control device determines occurrence of the glue-joint failure on the basis of whether the quantity of light received by the light receiving part is reduced by at least a predetermined value or a predetermined rate, and provides or gives a visual display or a warning of the occurrence of glue-joint failure.

Abstract: A gypsum composition includes a calcined gypsum and a starch urea phosphate.

Abstract: The present invention relates to a liquid dispersant composition for gypsum, containing (A) a particular polycarboxylic acid copolymer, a particular nitrogen-containing compound, such as a particular alkylamine, and water, and having pH of 7.0 or more and 13.0 or less at 20° C.

Abstract: Turning motion of gypsum slurry spouting onto a sheet of paper for a gypsum board liner is restricted for preventing maldistribution, deviation or irregular dispersion from occurring in the density distribution of the slurry on the sheet of paper. A mixing and stirring device for gypsum slurry has a circular casing forming a mixing area, a rotary disc positioned in the casing, and a tubular passage for feeding the slurry onto the sheet of paper for gypsum board liner. A chute has a fluid passage portion with its cross section being non-axisymmetric with respect to a center axis of the tubular passage, or a fluid passage portion varying a position of the center axis of the tubular passage by means of change or lateralization of the cross section of fluid passage.

Abstract: An object of the present invention is to provide a high-expansion gypsum composition in which the expansion coefficient of a general purpose dental gypsum material or the like is simply and effectively improved to such an extent that has never been achieved with conventional technologies without using any special material by adding an inexpensive additive even in a small addition amount, and furthermore another object of the present invention is to provide a high-expansion gypsum composition the setting expansion coefficient of which is appropriately controlled so that the contraction of a resin to be used can be precisely dealt with, the high-expansion gypsum composition being useful for manufacturing a reproduction model to be used in manufacturing a “non-clasp denture” having no problem in, for example, occlusion (adaptability).

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: A gypsum composition includes a calcined gypsum and a starch urea phosphate.

Abstract: An object of the present invention is to provide a high-expansion gypsum composition in which the expansion coefficient of a general purpose dental gypsum material or the like is simply and effectively improved to such an extent that has never been achieved with conventional technologies without using any special material by adding an inexpensive additive even in a small addition amount, and furthermore another object of the present invention is to provide a high-expansion gypsum composition the setting expansion coefficient of which is appropriately controlled so that the contraction of a resin to be used can be precisely dealt with, the high-expansion gypsum composition being useful for manufacturing a reproduction model to be used in manufacturing a “non-clasp denture” having no problem in, for example, occlusion (adaptability).

Abstract: The object of the present invention is to provide an embedding material composition for casting that makes it possible to conduct a favorable casting in the case where casting is conducted using a resin pattern that is different from a conventional wax pattern in disappearance temperature and disappearance behaviors through “rapid heating” excellent in treatment efficiency. The present invention relates to an embedding material composition for casting not using a heat-expandable refractory material as a main component, comprising: a binder; and a non-heat-expandable refractory material having an average particle diameter of 5 to 20 ?m as main components, in which a content of the binder is 25 to 40 parts by mass and a content of the non-heat-expandable refractory material is 60 to 75 parts by mass in the case where the total amount of the main components is 100 parts by mass, and the present invention also relates to a casting process using the embedding material composition for casting.

Abstract: The present invention provides a method for manufacturing a calcined gypsum wherein the mixing water amount is reduced and the setting time does not increase. As a raw gypsum is compounded with a carboxylic acid-type material and calcined, a calcined gypsum can be manufactured wherein the mixing water amount is small and the setting time does not increase. Furthermore, a regular gypsum board can be manufactured without reducing the productivity of the gypsum board even if a large quantity of recycled gypsum causing increase of the mixing water amount is used as a raw gypsum, because the mixing water amount is small and the setting time does not increase for the calcined gypsum manufactured as described above.