US 3854987 A
The disclosure of this application is directed to structural units, as for example, structural units of concrete, wood, paper, bradish cloth and the like to be used in the construction, building and other like industries, which are coated with a composition based on an alkali metal silicate, a sodium tripolyphosphite wetting agent and a filler to provide structural units having improved "sealant" and fire-resistant characteristics.
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Description (OCR text may contain errors)
AU lib X5 1 398549937 Michael, deceased United States Patent [191 Dec. 17, 1974 COATED STRUCTURAL UNITS HAVING IMPROVED PHYSICAL PROPERTIES David H. Michael, deceased, late of 3210 Five Oaks Place, Louisville,
Ky. 40207 by Margaret C. Michael, legal representative Filed: Jan. 2, 1973 Appl. No.: 320,189
US. Cl. 117/123 A, 52/515, 106/74, 106/84,117/123 B, 117/123 C, 117/147, 117/152, 117/169 A Int. Cl C09d l/02, B32b 13/04 Field of Search 117/123 A, 123 B, 123 C, 117/169 A; 106/74, 84; 52/515 References Cited UNITED STATES PATENTS 7/1889 Catlin 106/84 1,942,299 1/1934 Lemmerman et a1 106/74 1,989,833 2/1935 Ware 106/84 2,449,346 9/1948 Vannoy 106/84 2,756,159 7/1956 Kendall 106/84 3,180,746 4/1965 Patton et a1. 106/84 3,511,692 5/1970 Pratt 117/123 A Primary ExaminerWilliam D. Martin Assistant Examiner-William H. Schmidt  ABSTRACT "ing improved sealant and fire-resistant characteristics.
3 Claims, N0 Drawings COATED STRUCTURAL UNITS HAVING IMPROVED PHYSICAL PROPERTIES This invention relates to coated structural units which are characterized by improved properties. More particularly, this invention relates to structural units having wide utility in the construction, building and other like industries, as for example, structural units of concrete, wood, paper, bradish cloth and the like which are coated with a composition based on an alkali metal silicate, a wetting agent and a filler to provide coated structural units having improved sealant characteristics, i.e., structural units which are air-tight and having improved fire-resistant properties.
In current day mining operations, for instance, coal mining operations, good ventilation for the miners is essential to the safe and efficient operation of the mine. In order to provide the necessary ventilation, air is forced through the mine and directed to the desired areas by means of so-called stoppings. Stoppings are structural walls usually made of concrete which are used to block passages of the mine and to divert the air being forced through the mine to the working and other desired areas. As a rule, the stoppings are temporary walls and moved from location to location, as the need arises. Also, these stoppings are made air tight usually using cement and plaster, in order that they provide efficient blocking" action with respect to the air being forced through the mine.
it has been found, however, that plastering of the stoppings is a time consuming and expensive operation. Furthermore. the resultant plastered surface is usually brittle and is easily damaged. Consequently. the stoppings require constant repair in order to maintain airtight" characteristics.
The present invention provides coated structural units having excellent sealant characteristics, are resistant to surface damage and in addition are characterized by improved fire resistant properties.
The structural units of this invention, as stated, are coated with a composition based on an alkali metal silicate, a wetting agent and a filler.
Examples of suitable fillers for purposes of this invention are filamentous material such as inorganic fibers exemplified by asbestos fibers, steel wool fibers, bronze fibers, glass fibers and the like; organic fibers, such as cellulosic fibers, polyacrylonitrile fibers and the like rendered infusible by heat-treatment, polyethylene, polystyrene, polyurethane and the like. Particularly desirable filamentous materials are the asbestos fibers. Other suitable fillers are granular materials such as barium sulfate. cork dust, silica, mica, metal particles, clay, litharge, calcium oxide, zinc oxide, zinc dust, graphite. molybdenum disulfide, iron oxide, Cardolite resins which are reaction products of an aldehyde and cashew nut shell oil described in detail in U.S. Pat. No. 2.317.587. and the like.
Illustrative of alkali metal silicates are the sodium and potassium silicates as well as the commercially available. silicates which are sold by Philadelphia Quartz Co. as sodium silicate solution K and by Diamond Alkali as sodium silicate solution 47. Generally, these aqueous commercial solutions contain at least about l.5 moles Si per mole Na- O. preferably about [.5 to about 3.75 moles SiO- per mole of M1 0 and even more preferably about 2 to about 3 moles of SiO; per mole of Na O.
The wetting agents are well-known materials and are exemplified by the polyphosphites, silicones, ethoxylated alcohols, organo polysiloxanes, silicones and the like. Commercially these wetting agents are sold under the trade name of Tergitol, MinFoam, lX, NPX, 12-M- 10, Tween 20, Dow-Corning 199.
Formulation of the coating composition can be effected by simply admixing the components thereof in a Hobart mixer or a dough mixer. The alkali metal silicate, usually as an aqueous solution is charged into the mixer and the wetting agent and filler added thereto with agitation. Sufficient water is added and mixing is continued until a smooth coating solution or composition is obtained.
The resultant composition can then be applied by any conventional coating techniques, spraying, brushing, troweling and the like.
The thickness to which the coating is applied is not critical. Coatings less than about 5 mils effect air-tight surfaces.
The amount of filler and wetting agent relative to the amount of alkali metal silicate on a solids basis is, with respect to the filler about one percent by weight to about percent by weight, based on the weight of the silicate and with respect to the wetting agent, about 0.5 to about 10 percent by weight, based on the weight of the silicate.
The following examples further illustrate the present invention.
EXAMPLE 1 A composition, the formulation of which is noted below, was prepared in a Hobart mixer to a coating composion of a smooth, uniform consistency.
PARTS BY WElGHT Sodium Silicate (Aqueous solution containing 40 percent sodium silicate on a solids basis) 25 Asbestos 5 Sodium Tripolyphosphite (Calgon) 0.2
This coating composition was used to coat the following masonry structural units:
1. cinder blocks 2. cement blocks The structural units were air-tight and fire-resistant.
EXAMPLE 2 A composition. the formulation of which is noted below, was prepared in a Hobart mixer to a coating composition of a smooth, uniform consistency.
PARTS BY WEIGHT Sodium Silicate (described in Example I 46 Asbestos 4.5
-Continued PARTS BY WEIGHT Sodium Tripolyphosphite (Calgon) 0.4
Structural units of wood, paper and bradish cloth were also coated with compositions of Example I and 2 with equally good results.
What is claimed is:
l. A structural unit of concrete or cinder block coated with a composition consisting essentially of an aqueous solution of an alkali metal silicate containing at least about 1.5 moles SiO per mole Na O, a filler and a sodium tripolyphosphite wetting agent, wherein said filler is present in an amounm to about percent by weight, based on the weight of said silicate and said wetting agent is present in an amount of about 0.5 to about 10 percent by weight, based on the weight of said silicate.
2. A structural unit as defined in claim 1 wherein the said silicate contains about 1.5 to about 3.75 moles SiO per mole N320.
3. A structural unit as defined in claim 1 wherein the filler of the composition is asbestos.