Anthony L. Garnero appeals from a decision of the Board of Appeals affirming the examiner’s rejection of claims 2-12, all the claims in appellant’s application.1
The invention is a method of forming an insulating mat of expanded perlite, an inorganic siliceous material. When perlite is passed through a zone heated to a temperature such that the particles are in a “pyroplastic” state, combined water contained in the perlite particles is driven off. As a result, the particles expand and become porous. The porous particles still in the pyroplastic state are collected on an endless conveyor where they become fused together forming a porous mat. Claims 2 and 5 are illustrative i
“2. The method of producing a composite structure of an expanded perlite comprising the steps of heating the perlite while in movement individually in finely divided form to raise the temperature of the perlite to above 1200° F. but below 2500° F. whereby the perlite is caused concurrently to release combined water while the entire mass is in a pyroplastic stage to cause expansion, and projecting the individually heated particles of perlite onto a collecting surface to agglomerate the expand*590ing perlite while still in the expanded and pyroplasticc stage to form a composite structure.
“5. The method of producing a composite structure of an expanded perlite comprising the steps of heating finely divided perlite particles in movement in an individual finely divided state for a time concurrently to raise the temperature of the entire mass of the mineral to a pyroplastic stage during which the combined water is released to expand the particles and to flux the mineral, and projecting the heated particles of perlite onto a collecting wall to agglomerate the expanded perlite particles while in the expanded and pyroplastic stage to form a composite structure.”
The references relied on are:
Slidell 1,845,350 February 16, 1932 Wyatt 1,882,052 October 11, 1932 Hermann 1,929,425 October 10, 1933 Parsons 2,341,059 February 8, 1944 “Perlite, The Wonder Material,” Page Convertor Co. (pp. 1-3) (1949)
Parsons discloses the production of lightweight, porous, ceramic materials for insulation by passing ceramic particles through a high temperature zone and then fusing the particles in a collecting zone to form a composite structure. Ceramic material such as clay is ground into particles and passed through a furnace. According to the reference:
“The temperature of the furnace and the time allowed for the particles to remain therein are calculated to allow the surfaces of the individual particles to come into a fused or molten state. * * * The particles are collected in a zone of the furnace in a mass, each particle adhering to one or more of the others by virtue of their respective fused surfaces.”
Porosity may be obtained by expansion of gas within the particles. Thus,
“ * * * a combustible material such as sawdust, naphthalene, or other organic material is incorporated into the molded clay mass. The combustible material is then burned out during the firing, and voids are left in the product. Gas-liberating substances are also sometimes incorporated with the clay in order to lend porosity to the resulting product. * * *”
Parsons further states:
“In order further to increase the space between the particles, the addition of fluffing agents such as asbestos or mineral wool, cyanite, and the like is also within the scope of this invention. The fluffing agents may act to further separate the particles either by holding the particles apart mechanically or by liberating gas during the formation of the porous mass, thus increasing the size of the voids between the particles. * * * For low temperature work, asbestos or mineral wool works very satisfactorily. * * * Other suitable mineral fluffing agents are vermiculite * * * and silica, the latter preferably at or above 500° C., at which temperature it has an expanding effect. Gas-producing or gas-liberating materials such as gypsum may be incorporated into the dry mix which, when exposed to the high temperature, will volatilize and form cellular structures within the mass.
“Furthermore, to accelerate the softening of the surfaces and subsequent bonding action, a flux which is easily vaporizable, such as sodium chloride, may be introduced into the furnace * *
The examiner relied upon the Per-lite article for the suggestion of using perlite in the Parsons’ process. The article states that perlite possesses the high insulating properties of mineral wool and vermiculite and yet has high strength. Perlite is described as a volcanic glass containing 65 to 75% silica. It is stated that temperatures of 1500-2200° F. expand the perlite 600% to *5911500% or more in volume due to the formation of air or gas bubbles. In order for expansion to occur, “it is necessary to heat the glassy particles to the proper viscosity or softness, so that the moisture and/or gas entrapped in the ore will expand the softened mass into several times its original volume.”
The Perlite article, which is apparently an advertising brochure for a specific indirectly heated expansion furnace for producing separate particles of expanded perlite, states that several disadvantages result from the use of direct flame heaters. One disadvantage is that there is loss due to unexpanded ore. Another so-called disadvantage is that “there is a fusion of hot particles into clinkers.” Appellant argues that this statement would teach away from agglomerating as in the Parsons’ process. We disagree. Certainly agglomeration is a disadvantage when individual particles of expanded perlite are desired.' However, we find no suggestion that such agglomeration would prevent use of perlite in the Parsons’ process. Indeed, the fact that agglomeration takes place at normal expansion temperatures would indicate that perlite was well suited for the Parson’s process.
Both the examiner and the board felt that use of perlite in the Parsons’ process would be obvious because Parsons suggested the use of materials similar to perlite. We note that Parsons suggests the use of vermiculites and mineral wool in forming a porous mat. The Perlite article indicates that perlite has the insulating properties of mineral wool and vermiculite and approaches the structural strength of pumice and slags. Claim 2 calls for heating the particles to a temperature of “above 1200° P. but below 2500° F.” in order to release water from the particles and cause them to expand. Perlite discloses expansion temperatures of about 1500-2000° F.
The only limitation in claim 5 not present in claim 2 is:
“ * * * to raise the temperature of the entire mass of the mineral to a pyroplastic stage during which the combined water is released to expand the particles and to flux the mineral * *
Apparently this limitation is used in place of the “1200° F. but below 2500° F.” limitation of claim 2. Reference to applicant’s specification indicates that the pyroplastic stage and suitable agglomeration are achieved at temperatures as low as 1200° F. and that optimum expansion and agglomeration are achieved in a temperature range of 1800-2200° F. This coincides closely with the Perlite range of 1500-2000° F. We think that the references, when considered together, would suggest the expansion and agglomeration of perlite in the Parsons’ process.
The remaining claims are dependent upon claims 2 and 5. Claims 3 and 4 recite temperature ranges of 1600-2400° F. and 1900-2200° F., respectively. Claim 4 recites a particle size of less than 20 mesh and a heating time of from less than 1 to 360 seconds. Claims 6 and 7 call for the addition of a siliceous inorganic eutectic material. Claims 8, 9 and 10 recite the addition of an inorganic fiber of higher fusion point than the pyroplastic stage of the perlite. Claim 9 recites the amount of fiber, 0.5 to 10%, and claim 10 recites that the fiber is glass.
The portions of the record pertinent to the above limitations are summarized below. The recited temperature ranges overlap the 1500-2000° F. range disclosed by Perlite. With regard to particle size, we note that appellant states in his specification that “the size of the particles of perlite is not critical' * The eutectic material aids in bonding the perlite particles together. Parsons discloses the addition of a flux “to accelerate the softening of the surfaces and subsequent bonding action * * Although the addition of glass fibers is not disclosed, asbestos is added by Parsons as a “fluffing agent.” The board’s position was as follows:
“We agree with the Examiner that any differences, such as the par*592ticular dimensions of the perlite particles as in claim 4, or the specific amounts of the eutectic materials and the inorganic fibers (including the particular fiber) are mere matters of choice within the ordinary skill of the art. We note that Parsons shows that it is old to use fluxing agents (equivalent of the eutectic material) and fibrous material (the asbestos in the example).”
The appellant in his brief has not controverted the above holding of the board. He apparently is willing to test patentability on the broad claims, 2 and 5, although he did assign the above holding as error. At any rate, in the absence of clearly demonstrated error on the part of the board, we find no basis for reversal.
The decision is thus affirmed.
Affirmed.
. Serial No. 714,831 filed February 12, 1958 for “Structural Material of Expanded Minerals and Method for Manufacturing.”