摘要:
A building board comprising a cement substrate, a top coated layer formed on the front surface of the substrate, and a plastic sheet formed on the back surface of the substrate. The plastic sheet should preferably be formed of a polyethylene sheet. Since the impregnation of water from the back surface of building board can be effectively prevented, the change in dimension of board as a whole can be minimized.
摘要:
A moisture-tolerant structural panel comprising a gypsum board comprising a set gypsum core sandwiched between and faced with mats of glass fibers, wherein a free surface of one of said mats is coated with a combination of a mineral pigment, an inorganic adhesive binder and a polymer latex adhesive binder applied to said surface as an aqueous coating composition, said aqueous coating composition upon drying and setting, covering said mat to the extent that substantially none of the fibers of said mat protrude from said coating.
摘要:
A method for coating the sawed edges of gypsum wallboard to prevent dusting of gypsum particles in clean rooms. The method includes applying a water-dispersible polymers to the sawed edges of gypsum wallboard. The polymer forms a water-insoluble salt through an ion exchange with the calcium found in gypsum wallboard. The result is a tough, tack free, fast-drying coating that substantially reduces the levels of airborne gypsum particles that come from the sawed edges of gypsum wallboards.
摘要:
The feeder for short rods of a diameter of between 6 and 120 mm for a machine such as a turning lathe or an automatic lathe comprises a rod loading device having elements for holding a plurality of rods on an inclined plane and loading slides, a device for centering rods along an axis of alignment with respect to the machine tool, and a device for advancing rods in the machine tool. The holding elements are fingers which do not just hold a rod, but offer it, in the course of loading, a support surface in such a way that the rod is simultaneously supported by the finger and the loading slide. The feeder further comprises a device making it possible to adapt the position of the first rod to be loaded to the diameter of this rod when the limit stop for the course of the loading slide is adjusted to the diameter of the rod. This construction of the feeder avoids any impact of rods against the loading slide, and makes the machine more efficient owing to the semi-automatic adaptation to the variable diameter of rods.
摘要:
The invention provides a set gypsum-containing product having increased resistance to permanent deformation and a method for preparing it comprising forming a mixture of a calcium sulfate material, water, and an appropriate amount of one or more enhancing materials chosen from condensed phosphoric acids, each of which comprises 2 or more phosphoric acid units; and salts or ions of condensed phosphates, each of which comprises 2 or more phosphate units. The mixture is then maintained under conditions sufficient for the calcium sulfate material to form a set gypsum material.
摘要:
This invention relates to a process for making gypsum board comprising feeding a paper backing sheet and a fiberglass or plastic woven or non-woven scrim material in alignment to a board forming station, separating the paper and the scrim, feeding a high density calcium sulfate hemihydrate slurry into the trough formed between the paper and the scrim, and subsequently compressing the paper and the scrim into contact whereby the high density slurry is forced through the scrim, completely encapsulating the scrim in the high density slurry. As a result of this unique process, excellent bond is developed between the paper, the high density gypsum layer and the foamed gypsum core. The gypsum board has improved through-penetration strength.
摘要:
Methods and apparatus are disclosed for producing gypsum board having at least one facing sheet, a core of cementitious material such as low density gypsum, and an intermediate layer of bond promoting material, such as higher density gypsum located therebetween. The apparatus includes a forming table having a transverse gap. The facing sheet travels along the forming table over the gap. A spreader roller has an outer surface extending partially into the gap to depress the facing sheet. The bond promoting material is deposited on the facing sheet upstream of the spreader roller and the spreader roller outer surface rotates in the same direction as the facing sheet to coat the facing sheet with the bond promoting material. The core layer material is deposited on the facing sheet downstream of the spreader roller on top of the bond promoting coating. The speed of the spreader roller, the tension in the facing sheet, and the viscosity of the bond promoting material are varied within predetermined limits to adjust the thickness of the bond promoting material layer and prevent build up of said material on the spreader roller.
摘要:
A moisture-tolerant structural panel comprising a gypsum board comprising a set gypsum core sandwiched between and faced with mats of glass fibers, wherein a free surface of one of said mats is coated with a combination of a mineral pigment, an inorganic adhesive binder and a polymer latex adhesive binder applied to said surface as an aqueous coating composition, said aqueous coating composition upon drying and setting, covering said mat to the extent that substantially none of the fibers of said mat protrude from said coating.
摘要:
A system for making wallboard or backerboard sheets may include a mixer for mixing materials for making aerated concrete, at least one face layer supply, and a former downstream from the mixer. The former is for forming core material having opposing first and second major surfaces and comprising aerated concrete, and for securing at least one face layer from the at least one face layer supply onto at least one of the first and second major surfaces of the core material. The system may also include a cutter downstream from the former for cutting the core material and at least one face layer secured thereto into a plurality of wallboard or backerboard sheets. The provision of aerated concrete for the core provides many key advantages over conventional gypsum wallboard sheets, and/or conventional backerboard sheets, such as gypsum greenboard or cementitious backerboard, for example. In one class of embodiments, the former may further include an autoclave for curing the core material prior to securing the at least one face layer thereto. In another class, the former may further include an autoclave for curing the core material after securing the at least one face layer thereto.
摘要:
The present invention provides for the use of film-forming aqueous formulations comprising in dispersed form at least one crosslinked copolymer P for coating shaped mineral articles and for a method of coating shaped mineral articles, said copolymer P comprising in copolymerized form a) from 80 to 99.89% by weight of at least one monomer selected from esters of acrylic acid with C1-C12-alkanols, esters of methacrylic acid with C1-C8-alkanols, and monovinylaromatics, b) from 0.1 to 19.99% by weight of at least one monomer different from a), and c) from 0.01 to 1.9% by weight of at least one crosslinking monomer selected from esters of acrylic or methacrylic acid with linear or branched C3-C6-alkenols, cyclic C5-C7-alkenols and polycyclic C2-C12-alkenols.