claim as mv Invention: 1. A composition capable of setting to form a 55 hard porous mass comprising water , Portland cement, asbestos. and a flnely divided precipitated calcium silicate having an average part!(,le size not substantially in excess of about one micron, the..molecuiar ratio of SiO@-, to CaO in 60 aid silicate being not less tho-n aboiit two to nne, the ratio between said solid Ingredients being the following, expressed In parts by weight: Silicate --------------- 10 to 80 -------------- PortIand cement ------ 10 to 70 65 -------------- Asbestos ----------------------------- 5 to 40 the quantity of water being from about 75% to about 350% by weight of the drv ingredients. 2. A composition capable of setting to form a 6 one, the ratio between said solid ingredients being the fouowing, expressed in parts by weight: silicate ------------------------------ 10 to 80 Portland cement --------------------- 10 to 70 Asbestos ----------------------------- 5 to 40 the quantity of water being from about 75% to about 350% by weight of the dry ingredients, and said composition further comprising sugar as a retardant for setting. 3. A hard porous composition comprising asbestos and a setting product of a mixture of water, Portland cement, said asbestos and a finely divided precipitated calcium sflicate having an average particle size not substantially in excess of about one micron, the molecular ratio of SiO2 to CaO in said silicate being not less than about two to one, and the ratio between said three solid ingredients being the following: Silicate -------- --------------------- 10 to 80 Portland cement --------------------- 10 to 70 Asbestos ----------------------------- 5 to 40 !aid mixtures initially containing water amount- ingredients. 4. A method of preparing a hard, porous composition comprising providing a mixture of water, Portland cement, asbestos, and a finely divided precipita ed calcium silicate having an . t average. particie size not substantially in excess of about one micron, the molecular ratio of SiO2 to.CaO in said silicate being not less than about two to one, and the ratio between the solid ingredients being the following: Silicate ------------------------------ 10 to 80 Portland cement --------------------- 10 to 70 Asbestos ----------------------------- 5 to 40 said mixture initially containlng water amounting to from 75% to 350% by weight of the solid Ingredients, and curing said mixture. 5. A method of preparing a hard, porous composition comprising providing a mixture of water, Portland cement, asbestos, and a flnely divided precipitated calcium silicate having an average particle size not substantiaily in excess of about one micron, the moleciilar ratio of SiO2 to CaO In said silicate being not less than about two to one, and the ratio between the soild Ingredients being the following: silicate ------------------------------ 10 to 8; Portland cement --------------------- 10 to 70 Asbestos ----------------------------- 5 to 40 said mixture Initially containing water amountIng to from 75% to 350% by weight of the solid mgredients, and cu'ring said mixture at a temperature in e:ieess of 1001 C. 6. Por use in storing acetvlene. the combination with a receptacle capable of being closed and of withstanding internal pressure of amonolithic mass of porous composition contained within said receptacle comprising asbestoc; and a setting product of a mixture of water, said asbegtos, Portland cement and a finely divided precipitated calcium silicate having an average particle size not substantially in excess of about one micron, the molecular ratio of hard porous mass comprising water, Portland TO SiO2 tO CaO in said silicate being not less than cement, asbestog, and a flnely divided pre I cipt- about two to one, the ratio between said three solid ingredients being the following: tated calcium silicate having an averape particle size not substantially in excess of about one Silicate ------------------------------ 10 to 80 mleron, the molecular ratio of S102 to Cao In Portland cement --------------------- 10 to 70 said silicate being not less than about two to 75 Asbestos ----------------------------- 5 to 40

2,6021409 7 the amount of water in said mixture initially amounting to 75% to 350% by weight of the dry ingredients. 7. A composition capable of setting to form a hard porous mass, comprising about 25% by 5 weight of Portland cement, about 12.5% by weight of asbestos fiber, and about 62.5% by weight of a finely divided precipitated calcium silicate having an average particle size not substantiauy in excess of one micron and having a 10 r.ioiecular ratio of SiO2 to CaO of at least 2 to 1, together with water amounting to about 75% to 350% by weight of the other ingredients. 8. In an acetylene receptacle of the type in which acetylene is dissolved In a liquid solvent 15 contained -within a porous fuling material completely filling the receptacle, a monolithic mass of porous composition formed of a cured mixture of from 10% to 70% by weight of Portland ce- , ment, from 10% to 80% byweight of a flnely di20 vided precipitated caicium silicate forming an average particle size not substantially in excess of 1 micron and having a molecular ratio of SiO2 tO CaO of at least 2 to 1, and containing from 5% to 40% by weight of asbestos, said mix25 ture initially containing water amounting to 75% to 350% by weiglit of the solid ingredients. 9. In an acetylene receptacle of the type in which acetylene is dissolved in a liquid solvent contained within a porous fllling material com3( pletely filling the receptacle, a monolithic mass of porous composition formed of a cured mixture initiauy comprising about 25% by weig4t of Portland cement, about 12.5% by weight of as-. 8 bestos fiber, about 62.5% by weight of a finely dividedprecipitated calcium silicate having an average particle size not substantially in excess on one micron and being a molecular ratio of SiO2 tO CaO of at least 2 to 1, together with water amounting to about 200% by weight of the dry ingredients, said monolithic mass completely fllling said receptacle without voids and being characterized by mechanical strength and resistance to crushing and by a porosity of at least 75%. ROBERT C. BOLTR. REFERENCES CITED The follovving references are of record in the file of this patent: UNITED STATES PAT.ENTS Number Name Date 1,332,525 Smith ---------- I ---- Mar. 2, 1920 1,574,380 Endres ------------- lpeb. 23, 1926 1,567,663 Marpfflero ---------- Dec. 29, 1926 1,767,514 Dalen --------- June 24, 1930 1,920,358 Clark -------------- Aug. 1, 1933 2,146,448 ScOtt --------------- Feb. 7, 1939 2,316,487 Reichert ---------- Apr. 13, 1943 2,359,342 Winding ------------ (>Ct. 3, 1944 2,410,954 Sha-rp ------------- NOV. 12,'1946 21422;251 O'Brian ----------- - Tune 17, 1947 FOREIGN PATENTS Number Country Date 501,024 Cxreat Britain ----------- of 1939

UKU66 UL@L HLNGE EMMIN I 0 6 - 99 " 2 5 0 ; 2 4 0 ; 9 Patented Apr. 4, 1950 UNITED STATES PATENT OFFICE 2,502,409 POROUS COMPOSITION OF MATTER AND METHOD OF PREPARING THE SAME Robert C. Bour, Chicago, 111" assignor to National Cylinder Gas Company, Chicago, Iff., a corporation of Delaware No Drawing. Application June 22,1946, Serial No. 678,671 9 Claims. (CL 206-0.7K, 2 This invention relates to a porous composition of matter adapted for use as a heat insulating medium, as a sound insulating medium, and as a filler for acetylene cylinders. The invention further pertains to an acetylene cylinder pro- 5 vided with a filler conzisting of the porous composition of this invention. The invention also relates to methods of preparing the porous composit,ion of matter referred to. It is well known that acetylene, when com- 10 pressed, is subject to spontaneous decomposition reswting in a large increase in volume so that the compression of acetylene in cylinders is a dangerous procedure. To eliminate this danger, acetylene is commonly compressed in cylinders 15 by a process including providing a cylinder completely filled with a highly porous and inert filling material and containing a suitable liquid solvent for acetylene, and then forcing acetylene gas into such a cylinder under pressure. The 20 conventional inert porous fming material for use in acetylene cylinders comprises charcoal as an absorbent, diatomaceous earth as an interstitial fLUer, asbestos fiber serving to increase the mechanical strength, and Portland cement as a 2r) binder. Such a mixture is made up with water, and the resulting heavy mass is tamped into an acetylene cylinder which is then allowed to set for seven days. At the end of this period, the cylinder is heated under vacuum for seven dgys 30 at 500' F. to dehydrate the mass completely. The porosity of the resulting cylinder filler is about 76%. T.u general, the desirable characteristics of filling material for acetylene cylinders include a 35 porosit@ of between 76 and 83%, small pore size, water resistance, stability at from -40' to 130' P., ability to withstand rough handling without settling or formation of voids, sufficient mechanical strength to give support to the cylinder wall, 40 low specific gravity, high ctushing strength, short ' curing time, and capacity for convenient introduction into the acetylene cylinder. It will be noted that the above-described conventional fUling material has to be introduced into acetylene 45 cylinders by tamping, and requires prolonged treatment for curing or setting. It is, therefore, an important 'object of the present invention to provide a porous mineral composition suitable -for use both as a filler for 50 acetylene cylinders and as a heat or sound insulating medium and characterized by ea acity for P convenient introduction into acetylene cylinders prior to curing or setting, rapid curing or @,etting, high resistance to thermal and mechawcal - shock, 55 high crushing strength, low specific gravity, and good resistance to water and to acid or basic material. Another object of the present invention is to provide an acetylene cylinder having a - porous 60 firer characterized by the properties enumerated in the next preceding paragraph. Still another object of the present invention is to provide methods for the preparation of porous niineral composit,@ons of the nature indicated. According to the present invention, porous mineral compositions are prepared by the curing or setting of aqueous compositions comprising, besides water, Portland cement, asbestos, and a finely divided precipitated calcium silicate hav-, ing an average particle size not substantially in excess of aboiit one micron, the molecular ratio Of SiO2 to CaO in said silicate being not less than about 2 to 1. Such a silicate is disclosed in the United States Patent No. 2,287,700 to Muskat et al., and reference is made to saicta detailed description. Said silicate material is marketed under the trade name "Silene." Two grades of this trade marked material are available, one having an average particle size of from CL.3 to 0.35 micron, and another having an average particle size of about 0.2 micron. Hereinbelow, unless otherwise indicatet, the materiai of the smaller particle size is designated when the trade-mark "Silene" is used. It maY be noted in this connection that "Silenell having an average particle size of 0.2 micron tends to give a more porous composition than "6ilene" of larger particle size. The "Silene" found in the market is a hydrated calcium silicate containing 19% CaO, and 67% SiO2 and characterized by 14% loss In weight on ignition. The electron microscope indicates an ultimate particie size of 0.03 to 0.05 micron. The material appears to consist mainly of friable agglomerates which break up under the shearing forces imposed on milling or other treatment. My aqueous composition containing,"SilpnC, asbestos, and Portland cemen@t b@in@ to se-t'-- -alm--os-f-ir@medigtely@after@miiing and develops, within a few hours, -a strength which is comparable to that of the a@bove-mentioned conventional Mler after the latter has set for the usual seven day period. This rapid setting of my novel co'mposition is accompanied by a considerable evolutiori of heat believed to be a result of a chemical reaction between the water, Portland cement, and "Silene." It is possible that this reactionrp!E-pg du ----tAQ_tliq__4y4K4tion of tricalcium silicate present in the Portland 6'6iiient ---a-res-.u--- w-ith Itai-nA--it --E and'-of-c@i-c'ium-h.'v"d--ro-x-i'd-e-...ilffc - t@p_ ip urn r&@- -e-ts --wi-th- -t-h"e "Silene," since "Silene" is a hydrai@d calcium silicatecontaining less calcium hydroxide than the amount required to neutralize the silica present therein. The neutralization of the calcium hydroxide released from the Portland cement would cause the Portland cement to set more rapidly than otherwise, and probably

3 result in a set or cured product comprising, products of a reaction,bet,,xeen Portland.- cement and "Silene." In the above disclosed composition, the asbestos fiber contributes mechanical strength to the set or cured composition. Preferably,:relativ6lY long fibered asbestos is used comprising, 'for @instance, fibers one-half inch long. If desired, diatomaceous earth such as '@'Celite;" acetylene black, or any other fineily divided inert solid material can be incorporated as fmer or diluent. The limits for addition iof such fJllers are set by resulting diminution in mechanical strength, porosity, or other essential features. With respect to the amount of "Silene," Portland -cement, and.asbestos to be used, it.should be noted tbat, for best results, combinations of these materials should be used that do -not crack, that do not. shrink away from the wars of -a container,.that set at room.temperature within seven days, and that exhibit porosities of At least 759'o. Compositions containing less than 109'o "Silenell show.a,.porosity -of less than 75%. while compositions containing more than @80 9,1, "Silene" do not set..thorouglily.at room@temperature within seven days and show cracking. - Compositions -containing less than .10% -Portland cement -do not set, while compositions containing more than 700/o Portland cement show porosities of less than 75%. .Compositions containing.jess than 59'o asbestos sometimes.show cracks, while compositions @containing -more than 40o/D.asbestos are.too llbrous to - fLU the -container @without leaving large voids. Thw,.the limiting percentages within which most..operative compositions are to be found are.the forowing: Per cent "Silenell ----------- - ----------------- 10 to 80 Portland cement ------------------- - 10 to 70 2,502,409 4 In general, from 75 to 350% of -water by weight of -thedry:@material niay be em.ployed. The amount of water used thould -be sufficient to yield an easily flowable material, for convenient a filling of cyl'mders, and at the same tizne should not be sufficient:to cause shrinkage or formation of voids o ' n setting or curing. In compositions having relatively high Portland cement contents, more water zhas to -be used. Since "Silene" ab10 sorbs more -water than Portland cement, an increased Portland cement content tends to lower -the viseosity. For very apparent reasons, it is desirable to have a JlUer mixture retain its fluidity for a 15 period of several hours. @,I have found that the inclusion with.any Qne of -the above-disclosed aqueous compositions containing "Silene," Portland cement, -and asbestos, of sucrose in an amount, for instance, of 3go, retards setting ef2(j fectivekv.for more than four hours while increasing the strength of the finished product considerably. To eliminate voids, botb.in the prepared mixture prior to Mling a cylinder and in the fuled 2,-,,eyhnder, the prepared mixture may be subjected to strongvacuum (prior to being introduced into the ey.Under) with siinultaneous vibration or stirring, mntil allentrapped air is removed. If a very-high -vacuum is used, water wM be boiled 3(,off to some extent,,thus decreasing the fluldit3r slightly, but this.can easily be corrected byusing aslight-excess of water in the original mixture. The vacuum need be appIied only for a few minutes under the conditions indicated. If the .3 5 -acetylene , c .ylin der @is then evacuated before,this deareated -mixture is introduced and a vacuum applied to,.the top of @the cylinder while the.mixture :is poured into a funnel, the formation of vqids is -practically completely prevented. Asbestos ---------------------------- 5-to 40 4r@ Very satisfactory setting may -be effected -by 'The fouowing are examples of satisfactory co,mpositions -including "Silene," 'Portland tement, and asbestos: allowing 7the fllled acetylene cylinderto -stand -at room -temperatures for seven days and then bakin ,g --.the cylinder, -.with @the cap removed, to dryness. 'The TesUlting - monolithic masses -within -4.5 the Med cylinders -are characterized by good Per cent Per cent mechanical strength and @porosity. Ilowever, -Pereent -.Composition Number Portland Asbestos curi ng may be,greatly accelerated by capping a @C ement filled cylinder, placing the capped and fL]Ied 1 ----------------------------- 10 50 40 cylind er @in -a -steam oven kept at about 200- C. 2 ---------------------------- ; 80 10 io @50, -,for about 16 @hours, @removing,the cap and baking 3 ----------------------------- 75 10 15 the cylinder -to dryiiess. This treatmexit wa-s 4 ----------------------------- 70 10 20 5 ----------------------------- - 25 :70 .5 found to increase the compressive strength to 6 ------------ ----------------- 30 65 5 ahno9 t -double that -df the same fffler cured for 7 ----------------------------- 30 30 8 ---------------------------- 25 35 -.,40 seven :days at Toom -temperatures. - Tempera9 ---------- ------------------ 50 .25 'm 10 --------------------------- -- 20 -.go '55 tures,of 1750 C., 1500 C., and 120- C., have -aisc) 11 ---------------------------- ;61.5 30.8 -7.,-7 been eMI)IDYed. -At 'these lower temperatures, 12 ---------------------------- 13 ---------------------------- 56.,25 MOre Tapid -curing -and increa-sed mechanical 14 ---------------------------- .25 :12.5 streng th '(-as -compared -with setting at room 15 ----------------------------- so '37. 6 IZ5 tempemture) were noted, although, in general, @60 there @is -a -progressive increase in mechanical -The last -seven tabulated -compositions were strength -as the @curing tempers@ture is increased. niade iup with the percp-ntages of water tabulated Curing is preferably 6ffedted at a - temperature -in as follows: excess .-of 1-000 C. CYlinders filled with porous material are Wt,, ,in - 65 charged with acetylene by a -process including ComWition Number Per cent -of the steps @of filling Tthe porous material within Total Dry 'Mb6t erial the xoiitainer with a suitable solvent for acetylene, -such as -acetone,,and then pumping acety8 ----- - -------------------------- ----- lene :gas under :pressure into the cylinder. For 250 ----------------------------------------------- -4 -260 '.7 0 -instance, acetylene gas may be pumped into the 1( ---------------------------------------------------- '200 cylinder at 3-10 lbs. pressure for about 24 hours. 11 --------------------------------------------------- '224 12 -------- - --------- - ----------------------------- - - 250 A --oylinder fLUed -with -a composition made - up of 13 ---------------------------------------------------- 14 ---- - - --------------------------------------- - -- -260 65 lbs. "8ilene," 13 lbs. asbestos, 26 lbs. Portland 15 -- - --------------- - ------------------------------- -2M cement, and 1,98 lbs. water, cured as disclosed 75 berainabove at -room tempemture and tcharged f

tiRUaa IlLrLnLilLiL 2,502,409 5 with 38 lbs. acetone, was found capable of absorbing 20.7 lbs. of acetylene, while a similar container of the same capacity fllled with a conventional fibing material absorbed 19.8 lbs. acetylene gas in the presence of 38 lbs. acetone. 5When 40 lbs. acetone were introduced into each of these two cylinders, the cylinders containing my novel fluing material absorbed 21.25 lbs. of acetylene while the cylinder containing the conventional fflling material absorbed 19.25 lbs. joi acetylene. Thus, the f!Hing materials of my invention are equal, if not superior, to standard acetylene fillers 'with respect to capacity to absorb acetylene. At the same time the filling materials of my invention are distinguished by 15! .much greater mechanical strength, shock resistance, porosity, lower gravity, higher porosity, less tendency to form voids and to shrink away from the container walls, and by being capable of being introduced into the cylinder to 20 be filled by simple Pourlng through a funnel. The compositions of the present invention are also characterized by good heat insulating proper.ties, as shown by the following example, A mixture of 200 grams "Sflene," 150 grams Port- 2,,. ing to from 75% to 350% by weight of the soiid land cement, 50 grams asbestos, and 100 0 grams water, to which 3% sucrose was added, was prepared and allowed to cure at room.temperature for seven days. Blocks thus Prepared were then heated to dryness and tested by the flat piate W. method. The following results, expressed in B. t. u. per hour per square foot of stirface per deg-rees Fahrenheit of temperature difference between OPPosite surfaces for one inch thickness a,t the temperatures listed, were obtained: 3 5 80' P ---------------------------------- 0.64 1500 p ---------------------------------- 0.655 2500 F ---------------------------------- 0.67 3500 p ---------------------------------- 0.70 4 0 Due to the high mechanical strength, shock resistance, and porosity of the set compositions of the present invention, such compositions can also be used -whenever a solid material having these properties is desired. 4.5 It should be understood that many variations in procedure and composition are permissible without departing from the principles of this invention and without sacrifleing the advantages mentloned hereinabove, and it Is, therefore, not o(j my purpose to limit the patent granted on this invention otherwise than necessitate&. by thie scope of the appended claims. T