Plastic and nonmetallic article shaping or treating: processes – Forming articles by uniting randomly associated particles – Utilizing diverse solid particles
Reexamination Certificate
2000-03-30
2002-06-25
Silbaugh, Jan H. (Department: 1732)
Plastic and nonmetallic article shaping or treating: processes
Forming articles by uniting randomly associated particles
Utilizing diverse solid particles
C264S109000, C264S333000, C106S690000, C106S691000, C366S007000
Reexamination Certificate
active
06409951
ABSTRACT:
The present invention relates to a process for producing an inorganic molded product which is suitable for use, for example, as a building material or an industrial structural material or member. Particularly, it relates to a process for producing an inorganic molded product which is excellent in strength, water resistance, thermal shock resistance and dimensional stability as compared with conventional inorganic material such as cement material or calcium silicate material.
Heretofore, cement plates, calcium silicate plates, etc. are widely used as building materials or as structural materials or members in an application where non-combustibility is required. However, cement materials and calcium silicate materials contain hydration water, since water is involved in hardening these materials. Accordingly, if such cement materials and calcium silicate materials are exposed to a high temperature of a level where the hydration water evaporates, cracks may form, whereby the dimension may substantially change, and the strength may remarkably decrease.
As an inorganic material which is durable at such a high temperature, a hardenable composition comprising phosphoric acid and/or a phosphate and various metal compounds, or an inorganic material obtained by hardening such a hardenable composition, has been proposed. Further, various molded products, structural materials and building materials having such inorganic materials reinforced by reinforcing materials, have been proposed.
For Example, JP-A-47-2424 proposes a semi-rigid heat insulating refractory comprising neutral magnesium phosphate, an alkaline earth metal oxide, silica, acid oxides other than silica and inorganic fibers and having a density of at most 0.9 g/cc, a melting point of at least 1500° C. and a working temperature limit of at least 1200° C.
Further, JP-A-51-2727 proposes a process for producing an inorganic building material plate, wherein a green plate obtained by mixing cement with a reinforcing material, a filler, etc., followed by sheeting, is coated with a composition obtained by mixing and reacting three components i.e. phosphoric acid and/or a phosphate, aluminum and/or an aluminum compound and a Group IIA metal and/or a Group IIA metal compound, by itself or together with a proper amount of water, and the plate is then cured.
Further, JP-A-55-51768 proposes an inorganic composition for low temperature burning, which is prepared by incorporating a reinforcing material durable against a burning temperature with an upper limit of 750° C., to an inorganic molding material made of a mixture comprising (a) a natural matter or composition, or glass, containing alumina, silica or both as the main component, and (b) phosphoric acid or its salt. As such a reinforcing material, glass fibers, rock wool, metallic fibers, carbon fibers and mixtures thereof, are mentioned.
Further, JP-A-55-95667 proposes a construction material comprising a glass fiber-reinforcing material, a copper-chromium-phosphate binder or an aluminum-chromium-phosphate binder and a powder mixture of kaolin and a magnesium-containing inorganic extender, as a neutral active doping agent.
Further, JP-B-59-3958 discloses a process for producing a pliable, inorganic, non-combustible molded product, wherein an aqueous slurry mixture prepared by mixing proper amounts of a quick-acting hardener and a slow-acting hardener to an inorganic film forming agent as the main agent, is impregnated in and coated on a shaped fibrous base material such as paper, woven fabric, non-woven fabric or a mat, and then hardened. As the inorganic film forming agent, a metal phosphate such as aluminum phosphate or aluminum polyphosphate, is disclosed. As the hardener, magnesium oxide, zinc oxide, aluminum hydroxide, calcium hydroxide or calcium silicate, is, for example, mentioned. As the fibrous base material, glass fibers are, for example, disclosed.
Further, JP-A-60-228142 proposes a bonded composite structure comprising at least one layer of at least one type of layer forming material, each layer of the layer forming material being bonded to an adjacent layer by a water resistant phosphate adhesive material obtained by a reaction of a composition comprising a metal oxide, calcium silicate and phosphoric acid. As examples of the layer forming material, woven fabric, non-woven fabric and chopped glass fibers are mentioned.
Further, JP-B-61-58420 discloses a method for producing a filled inorganic plastic cement, which comprises mixing a microfiber filler to a reactive aqueous slurry comprising a magnesium salt, a water-soluble phosphate component and magnesium oxide and having a viscosity of from about 700 to 15000 cps, in an amount of from 2 to 40% by weight of the slurry.
With the hardenable compositions of the above mentioned prior art comprising phosphoric acid and/or a phosphate and various metal compounds, the reaction of phosphoric acid or a phosphate with the metal compound as its hardener, starts and proceeds immediately after the preparation of the compositions. Accordingly, depending upon the type of the hardener, the pot life of the hardenable composition may sometimes be shortened. Further, it may happen that as the time passes after the preparation, gelation of the hardenable composition proceeds, and its viscosity tends to be high, whereby when the hardenable composition is combined with a fibrous reinforcing material, impregnation of the composition to the reinforcing material tends to be inadequate, and the mechanical strength of a molded product obtained by hardening the hardenable composition, tends to be low.
As is different from a hydraulic cement material or calcium silicate material, in the process of hardening of the above hardenable composition, most water required for the composition to flow at the time of molding into a desired shape, will not contribute to the hardening of the composition and will be discharged as excess water. In such a case, water present at the surface or in the vicinity of the surface of the hardenable composition will be discharged relatively easily without bringing about defects such as voids to the structure of the resulting molded product.
However, in a case where the reaction or hardening of the hardenable composition is quick, only the surface portion may firstly be hardened before the internal water will be discharged by evaporation, and water tends to remain in the interior of the composition. In order to complete the reaction and hardening of the hardenable composition, heating is required, and even if the water remaining in the interior will be evaporated by this heating, it will hardly be discharged, and the evaporated water is likely to form bubbles which in turn may form voids in the interior of the composition, expand the composition which is not yet completely hardened or cause cracking, thus leading to deterioration of the appearance or mechanical strength of the molded product.
For the purpose of solving the above problems by suppressing the reaction of phosphoric acid or a phosphate with various metal compounds in the hardenable composition or improving the working efficiency or moldability during the production of a molded product, JP-A-4-317403 proposes to incorporate an organic liquid buffer to a hardenable composition, and as such an organic liquid buffer, a carboxylic acid, an amine or urea is, for example, mentioned.
However, the carboxylic acid or the amine to be used as the organic liquid buffer in the technique disclosed in JP-A-4-317403, will not evaporate or decompose by the heating to complete the hardening of the hardenable composition, and accordingly, it will remain in the hardened composition i.e. in the interior of the molded product. If the carboxylic acid remains in the interior of the molded product, there will be a problem that the water resistance of the molded product tends to be low. Further, if the amine will remain in the interior of the molded product, there will be a problem that when the molded product is exposed to a high temperature at a level of e.g. at least 400° C., the carbo
Inoue Akira
Onoue Seitaro
Asahi Fiber Glass Company Limited
Harris Adam R.
Silbaugh Jan H.
LandOfFree
Process for producing an inorganic molded product does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for producing an inorganic molded product, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for producing an inorganic molded product will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2921179