The present invention provides a composition, a gypsum board and their preparation method and the use of ascorbic acid as an anti-sagging additive in a gypsum board. Said gypsum board comprises set gypsum prepared from the composition; while said composition comprises hemi-hydrate gypsum, water and a compound comprising ##STR00001##
group and no carboxylate groups. The set gypsum prepared from the said composition shows better anti-sagging or deformation resisting property. The gypsum board of the present invention is hardly distorted and has stronger stability even in the condition of high humidity, thus improve the quality of the gypsum board to meet the demands of the customer.

A hole former for use in casting a gasket within an opening of a structure of the type used in underground water systems, such as a manhole. The hole former includes a body defining a central axis and an outer peripheral surface, with at least one gasket retention element projecting radially outwardly from the outer peripheral surface to interface with a corresponding locating feature of the gasket. In this manner, axial shifting or movement of the gasket with respect to the hole former is restricted, thereby positively locating and retaining the gasket on the hole former before and during the casting process. The hole former may have a compound curvature, with the gasket retained around the periphery of the hole former in a compound curved configuration.

A hole former for use in casting a gasket within an opening of a structure of the type used in underground water systems, such as a manhole. The hole former includes a body defining a central axis and an outer peripheral surface, with at least one gasket retention element projecting radially outwardly from the outer peripheral surface to interface with a corresponding locating feature of the gasket. In this manner, axial shifting or movement of the gasket with respect to the hole former is restricted, thereby positively locating and retaining the gasket on the hole former before and during the casting process. The hole former may have a compound curvature, with the gasket retained around the periphery of the hole former in a compound curved configuration.

A duct coupler assembly includes a female duct coupler, where the female duct coupler is coupled to a first duct segment. The female duct coupler includes a female duct coupler body having an inner surface having an inner diameter and a bayonet slot formed therein. The duct coupler assembly further includes a male duct coupler. The male duct coupler is coupled to a second duct segment. The male duct coupler includes a male duct coupler body having an outer surface having an outer diameter, where the outer diameter is smaller than the inner diameter of the inner surface of the female duct coupler body. The male duct coupler has a bayonet post extending from an outer surface of the male duct coupler body, and the male duct coupler body is positioned within the female duct coupler body such that the bayonet post is positioned within the bayonet slot wherein the male duct coupler is coupled with the female duct coupler.

A three-dimensional object is obtained by repeating multiple times forming a ceramic powder layer formed of a ceramic powder and applying to a desired region of the ceramic powder layer a liquid precursor composition at least containing at least any one of a metal alkoxide, a metal chloride, a hydrolysate of the metal alkoxide and a polycondensate of the hydrolysate, and water, thereby obtaining a laminated body; subsequently heating the laminated body at a temperature lower than the sintering temperature of the ceramic powder; and removing the ceramic particle in a region to which the precursor composition has not been applied.

The invention is directed to a process for producing a cured 3D product comprising the following steps: (a) providing a form negative mould of the 3D product comprising of one or two formed plastic sheets as obtained by thermoforming corresponding with the shape of the 3D product; (b) adding a liquid curable composition to the mould such that the inner surface of the mould is covered by the curable composition; and (c) solidifying the curable composition wherein a solidified layer or body is formed having the shape of the 3D product; wherein the cured 3D product is a radiation cured 3D product; and wherein the step (c) a radiation curable composition is solidified by radiation through the plastic sheet of the mould to form a solidified layer having the shape of the 3D product.

The invention is directed to a process for producing a cured 3D product comprising the following steps: (a) providing a form negative mould of the 3D product comprising of one or two formed plastic sheets as obtained by thermoforming corresponding with the shape of the 3D product; (b) adding a liquid curable composition to the mould such that the inner surface of the mould is covered by the curable composition; and (c) solidifying the curable composition wherein a solidified layer or body is formed having the shape of the 3D product; wherein the cured 3D product is a radiation cured 3D product; and wherein the step (c) a radiation curable composition is solidified by radiation through the plastic sheet of the mould to form a solidified layer having the shape of the 3D product.

The present invention provides a hydraulic composition for an additive manufacturing device having an excellent initial flexural strength development property and dimensional stability, the hydraulic composition for an additive manufacturing device including: 1.5 to 14 parts by mass of a polymer with respect to 100 parts by mass of an inorganic binder. In addition, the present invention preferably provides a hydraulic composition for an additive manufacturing device in which the inorganic binder contains 50 to 100 mass % of a calcium aluminate with respect to 100 mass % of the entire inorganic binder, and more preferably provides a hydraulic composition for an additive manufacturing device in which the inorganic binder contains 0 to 50 mass % of rapid hardening cement with respect to 100 mass % of the entire inorganic binder.

The present invention provides a hydraulic composition for an additive manufacturing device having an excellent initial flexural strength development property and dimensional stability, the hydraulic composition for an additive manufacturing device including: 1.5 to 14 parts by mass of a polymer with respect to 100 parts by mass of an inorganic binder. In addition, the present invention preferably provides a hydraulic composition for an additive manufacturing device in which the inorganic binder contains 50 to 100 mass % of a calcium aluminate with respect to 100 mass % of the entire inorganic binder, and more preferably provides a hydraulic composition for an additive manufacturing device in which the inorganic binder contains 0 to 50 mass % of rapid hardening cement with respect to 100 mass % of the entire inorganic binder.

Provided is a material for molding, without a mold, a highly uniform structure comprising a resin and a non-resin such as metals and ceramic. The molding material provided by this invention is formed of a powder comprising a resin and at least one species of non-resin selected among metals and ceramic. The resin material has a uniformity index N below 0.2. N is determined by depositting the powder in a softened or melted state to form a structure in a temperature range between the resin material's minimum molding temperature and maximum molding tempeature+100 C.; measuring the structure's porosity Rn at 12 locations by image analysis; and dividing the variance of porosity Rn by the average porosity Rn. The minimum and maximum molding temperatures are the lowest and highest heater temperatures at which the resin material can be molded at a pressure of 3500 psi by injection molding, respectively.