Патент USA US2412156код для вставки
Patented Dec. 3, 1946 2,412,156 UNITED STATES PATENT, OFFICE 2,412,156 RETARDER , George D. King, Chicago, andManvel C. Iylailey, Elmhurst, Ill., assignors to. United States, vGyyp sum Company, Chicago, III-.-, a corporation of Illinois No Drawing. Application November 4, 1940, ) Serial No. 364,240 '20 Claims.‘ (Cl. 106-112) 1 2 V The present invention relates to an improved form of retarder, such as is used for prolonging of 70 per ‘cent sodium, hydroxide, which is the commercial strength of caustic soda. The pro the‘ time of set of gypsum plasters and the like, and also to methods for its preparation. tein is heated in this sodium hydroxide solution at a temperature of about 190° F. for a period One of the objects of the invention is to pro vide a retarder which is stabilized against de terioration by age, so that it will not change in is mixed with 1200 pounds of quicklime. of about 3 hours, , The resultant hydrolyzed mass The quicklirne reacts with the water in the mixture to form calcium hydroxide, thus liberating a large its retarding characteristics when incorporated amount of heat. As a result of this heating, ex with plaster and the plaster subsequently is put 10 cess water is evaporated so that eventually a into storage. granular product is obtained which is substan A further object of the invention is to pre tially dry. ,It is apparent that the quantities re‘ pare‘ a‘ retarder consisting of hydrolyzed kera cited may be varied as desired to suit the type tinaceous material, lime, and some form of car bon dioxide or carbonate, preferably by carbona tion of the ?nished retarder either by means of of raw materials employed, strength of retarder carbon dioxide gas or by means of a water-solu in amounts insu?icient to effect complete drying ble carbonate. While keratinaceous retarders are quite old in the art of preparing set-retarded plasters, a dif ?culty is found in connection with these retarders of the mass or hydrated limev may be substituted. In either case drying is completed by external means. The ?nal product thus obtained is a pul required, etc. If desired, quicklime may be added » verulent granular material which may be ground ?ne enough to permit of mixing with the plaster. in that their retarding e?iciency changes with As thus far described, the process is a, descrip age. Prior art retarded plasters stored under tion of the prior art. The present invention is weather conditions‘ favoring rapid change in set an improvement thereon and di?ers in that car-é ting time may be affected so that an increase of 100 per‘ cent in setting time Within a period 25 bon dioxide in some form is introduced into the retarder. In accordance with this invention, this of about two weeks is observable. Setting time may be done in a number of ways, such as by mayiurther increase 200 to 300 per cent after carbonating the retarder prior to the elimination two or three months or storage under such con of all of the water by introducing carbon dioxide ditions. This variation in setting time with age gas into it or by adding a water-soluble carbonate leads to trouble with slow set on the job when to the dissolved keratinaceous material prior to old plasters are used; and in order to be as the addition of the lime thereto. Both methods sured of uniform setting characteristics, it is nec produce similar results. Variations of these proc essary to use fresh, unaged plaster. On- the other esses may also be practiced. _ hand, a plaster containing a retarder made in In preparing the retarder by the ?rst alterna accordance with the‘ present invention will in 35 tive (i. e., by the introduction of the carbon di crease but slowly in setting time and in some cases not at all, even after storage for six months oxide gas), in accordance with one‘embodiment under severe aging conditions, which,- it will at of this invention, one method of procedure is as once be apparent, is a very great advantage. follows: The gelatinous, glue-like hydrolyzed pro tein is mixed withquicklime in a pressure-tight vessel in which the original hydrolysis with the Inaccorda-nce'with the ‘prior art, a retarder may be prepared» by digesting a quantity of keratina caustic soda has taken place, either at atmos pheric or superatmospheric pressure, as above ceous material,» such as pulverized animal hair and hoofs, in a- solution of caustic soda at ele vated temperatures and at atmospheric or super atmospheric pressures. --To the resulting prop erly hydrolyzed mass, quicklime or hydrated lime is added. described. Cir We prefer to regulate the water-. ‘ I quicklime ratio so that complete drying will not be effected by the lime added. Preferably, about The amount’ of- quicklime may be so 5 per cent to 10 per cent of free water should re--_ regulated that it combines chemically with a large proportion of the water ,present and‘ the re maining water is driven‘ o? by the heat of re‘-: action whereby a dry product results. If lesser amounts of q'uicklin'ie' are used Or if hydrated‘ main‘ in the limed retarder after hydration of lime is' substituted, the excess‘ water may be re moved by external means, such as heating. For example, a retarder of the prior art may be pre-' pared as follows: 800 pounds of pulverized animal hoofs, hair, or other type of keratinaceous ma‘-‘ terial, are introduced into‘ 1000 pounds of wa'—" ter in which there have been dissolved 160 pounds the lime. Satisfactory results are obtained, how C ever, with‘ greater or lesser‘ amounts of free wa'; ter than indicated. Carbon dioxide gas is then introduced into‘ the vessel so‘ as to build up‘ a pres; sure inside the vessel of about 5 pounds per square inch" sup'e‘ratmo'spheric', equivalent‘ to about 20 pounds absolute pressure. An‘ alterna'-‘ tive process is to proportion the water-quicklime ratio so as to effect complete drying by reaction of water with‘ quicklime, seal‘ the pressure-tight vessel prior‘ to completion of hydration of the 2,412,156 3 thereafter quicklime is added, in exactly the same manneras in preparing ordinary retarder of the prior art. The drying and grinding steps are similar to those employed in the prior art. We carbonation, the remaining free water will be au tomatically released. The pressure vessel may be _ e - provided with agitators which are kept running to accelerate the absorption of the carbon diox . ide, which may require about 30 minutes. The amount by weight of carbon dioxide gas which is allowed to become absorbed by the retarder mix lies preferably between 5 per cent and 10 per 10 cent based on the total weight of ?nished retard- _ er, or about 20 per cent on the basis'of the ground hoofs although or. other it has keratinaceous been found that material as little employed,‘ as 2 per ‘ 4 ates within the hydrolyzed keratin solution, and lime, and carbonate in the manner indicated. Upon release of pressure following completion of do not attempt to explain the reaction which oc ours with carbonation to impart the unique char acteristics of increased stability to retarders pre pared in accordance with our disclosure. The re= action is evidentlymore complex than the mere carbonation of a portion of the added lime or caustic soda. We have found, for example, that ‘retarder prepared with addition of powdered - limestone or calcium carbonate, or a mixture of cent of carbon dioxide calculated on the dry 15 quicklime and limestone, in place of lime, is no more stable or resistant to change in strength weight of the entire mass will give useful results, with aging than the prior art retarder. It may and an absorption as high as 15 per cent (calcu be that carbonation of a limed‘retarder mix, or lated on ‘the dry weight of the entire mass) is also addition of a soluble carbonate to such a mix, effective. However, if the 15 per cent is exceeded results in the formation of a "complex calcium the results are notas desirable as they are be proteinate containing carbonate in the molecule, tween 5 per cent and 10 per cent, for a decrease which material is essentially more stable and re in the efficiency of the retarder occurs. After the si'stant to chemical changes upon exposure to air desired amount of carbon dioxide has been ab than the prior art type of product. Regardless sorbed,‘ free moisture is removed from the mate rial by opening the autoclave and allowing the 25 of any theory, it is known that the [process de material to dry, either naturally or assisted by scribed produces a retarder which is essentially arti?cial means. Finally, the dry retarder is suit stable and ‘resistant to changes in strength on’ ably ground to a ?neness which permits its‘in passage of time. I . corporation with the plaster. It is not necessary Both methods of producing the retarder‘ yield to employ pure CO2 gas for the carbonation. We 30 substantially equivalent results, and they are both have found, for example, that lime kiln flue gas, considered to be part of the same invention. , containing 20 per cent to 40 per cent of CO2, is In order to demonstrate the advantages which a satisfactory source of cheap CO2 for this proc are obtained by the use of the present invention ess. Ordinary flue gas from boilers or furnaces, there is shown hereinbelow, in the form of a table, with a C02 content as low as 7.5 per cent to 10 35 the setting time of set-stabilized plaster, using on per cent may also be employed. The other gase the one hand ordinary untreated retarder and onv ous constituents of such mixtures do not affect the other hand the retarder of the present inven the quality of the ?nal product, although of tion. The term “set-stabilized plaster” is in course the carbonation reaction proceeds with tended to cover a plaster of the calcium sulfate greater speed as 002 concentration is increased. 40 type which is stabilized as to its setting time The pressure required for carbonation is not ‘crit against the adventitious admixture of either re ical, andour process may be employed under any tardive or accelerative in?uences, such types of pressure from atmospheric and upward. How plasters being fully described in the patents to ever, time requirements for effecting the desired Gallagher, No. 1,683,539, and King,‘ Nos. 1,989,641, degree of carbonation are reduced by operating 2,078,198, 2,078,199 and 2,078,200. While the under positive pressure. plasters of the aforementioned patents maintain If instead of using carbon dioxide gas it is de their setting time irrespective of whether further sired to‘introduce the carbonate ingredient by retarder or further accelerator gets into them, means of a salt, the process may be carried out as follows: After the keratinaceous material has 50. they nevertheless exhibit an increase in setting time as they get older, and it is this defect that been digested by the caustic soda, which in this the present invention cures. In other words, the case,~if desired, need not be done under pressure, plasters made in accordance with the present in there is added to the glue-like mass, prior to the vention are set-stabilized not only against job re introduction of the lime, a suitable quantity of a soluble carbonate, such for example as ammoni 55 tardive and accelerative influences but also against lapse of time, which is a distinct improvee um carbonate, ammonium bicarbonate, sodi ment-over anything that has ever been done in um carbonate, sodium bicarbonate, or equiv this art. In the table therefore, where mention alent other water-soluble salts of carbonic is made of a lime-alum plaster formula with un acid. Sufficient carbonate is preferably added treated retarder, this refers, for example, to'the to’ produce a C02 content Of about 5 per cent plaster of King patent No.1,989,641, while where on the basis of the ?nished dry retard mention is made of carbonated retarder, the re ers. The agitators are kept running to insure a tarder of the present invention is referred to. complete solution or dispersion of these carbon Setting times of aged plasters Plaster - I Mix _ ‘ 1 Fresh 2 wks 4 wks 6 mo. Hrs. Min Hrs. Min Hra. Min. Hrs. Min. Lime-alum plaster formula with untreated retarder ..................... __ gz/gasg?aéa‘if 4 6 g8 £7‘ Lime~alum plaster formula with 00: treated retarder ................... ._ gizastg?gei _ I i 2 2(5) 2 Lime-alum formula with untreated retarder _____________________________ _. Lime-alum formula with carbonate-treated retarder ((NH4)HCO3) ...... _. 2% sanded. _ .. 2% sanded. . ._ I 1 Neat: Mixed with water only on glass mixing board. I 2% sanded: Mixed with 2% parts of washed sand and water on glass mixing board. 4 5 40 20 ‘ég ______________________ __ ______________________ ._ 13 28 g 353 12 6 00 15 2,412,150 6 Referring to the above table, the terms"‘neat” andpartially carbonating the resultant material and “sanded” are fully explained in the table itself. All plasters therein mentioned were aged by vadding carbon dioxide gas thereto. ,7. The process of producing a plaster retarder comprising hydrolyzing a protein material'with an alkali, adding- lime to the resulting mixture, under similar temperature and humidity condi tions. It will be seen, referring for the moment to the CO2 treatedretarder and comparing it with un and partially carbonating the resulting material by adding a water-soluble carbonate theretoin an amount to provide a carbonated retarder hav treated retarder in the set-stabilized plaster, that ing a combined carbon dioxide content of less in the neat test the original setting time of the latter was 3 hours and 55 minutes, which in 10 than about 15 per cent by weight (dry basis). 8. The process of producing a calcined gypsum creased at the end of 6 months to 13 hours, while plaster retarder which comprises hydrolyzing in the sanded test the original setting time was keratinaceous material with alkali, adding lime 4 hours and 55 minutes, which increased in 6 thereto and treating the said retarder mixture by months to 9 hours and 50 minutes. In the case of the gas-carbonated retarder, however, on the 15 con?ning it in a closed airtight space and. forcing into said space carbon dioxide so as to build up sanded test the setting time originally Was 4 hours superatmospheric pressure within the space to and 10 minutes, at the end of four weeks it was facilitate the absorption of the carbon dioxide. 4 hours and 45 minutes, and at the end of six 9. The process of producing a calcined gypsum months it had increased to only 5 hours and 50 minutes. These tests indicate what a remarkable 20 plaster retarder which comprises treating keratinaceous material, such as animal hoofs, degree of stabilization has been attained. Com with water and sodium hydroxide at a tempera paring this with a retarder carbonated with, for ture of about 190° F. for about three hours to hy example, ammonium bicarbonate, it will be seen drolyze the said keratinaceous material, carrying that the setting time was 5 hours and 20 minutes when freshly made and at the end of 6 months 25 out the aforesaid operation in a vessel capable of being made pressure tight, adding quicklime it had increased by only 55 minutes to a time of thereto and then introducing into the resultant 6 hours and 15 minutes. Comparing this with a mixture carbon dioxide at superatmospheric pres set-stabilized plaster with an untreated retarder, sure while maintaining in the vessel a pressure it will be seen that the latter when freshly made had a set of 4 hours and 40 minutes, and at the 30 above that of the atmosphere, to carbonate the alkaline content of the mixture to a degree suf end of six months it, had increased to 12 hours. ?cient to stabilize the resulting retarder. Our new stabilized retarder may of course also 10. The process of producing a retarder which be used to advantage in plasters which do not comprises hydrolyzing keratin by means of so contain the job set-stabilizing ingredients such dium hydroxide, adding a soluble carbonate as alum and lime. ' thereto in an amount such that the total com From what has been said hereinabove, it will be bined carbon dioxide content of the resulting quite apparent that a great advance has been retarder is less than about 15 per cent by weight made in the stabilization not only of the retarders (dry basis), and then adding quicklime, and dry but of set-stabilized plasters containing the same. 40 ing the resulting mixture. It is to be understood that the use of equivalent 11. The method of protecting ' hydrolyzed keratinaceous materials or the substitution of proteid retarder against changes in its e?iciency, other proteins therefor, such as soy bean meal, which comprises partially carbonating the sponge waste, ?sh scrap, etc., is to be considered retarder with a carbonating agent under con as within the scope of the present invention, for ditions to produce a carbonated retarder having which the following is claimed. less'than about 15 per cent by weight (dry basis) We claim: of combined carbon dioxide. 1. The process of producing a plaster retarder 12. A plaster retarder comprising a carbonated comprising partially carbonating an alkaline, hy hydrolyzed protein having a combined carbon drolyzed, proteinaceous material with a carbonat 50 dioxide content of less than about 15 per cent by ing agent to produce a retarder containing less weight (dry basis). than about 15 per cent by weight of combined [13. A plaster retarder comprising a carbonated, carbon dioxide (dry basis). hydrolyzed keratin having a combined carbon 2. The process of producing a plaster retarder dioxide content of less than about 15 per cent by comprising partially carbonating an alkaline, hy drolyzed, proteinaceous material by addition of 55 carbon dioxide. 3. The process of producing a plaster retarder comprising partially carbonating an alkaline, hy drolyzed, proteinaceous material by the addition weight (dry basis). 14. A plaster retarder comprising a hydrolyzed protein, lime, and a carbonate formed therein by chemical means, the carbonate having a com bined carbon dioxide content of less than about 15 per cent by weight (dry basis) of the retarder. of 2 to 15 per cent by weight of carbon dioxide _ 15. A plaster retarder comprising a mixture of hydrolyzed keratin and lime, protected against gas thereto based on the dry weight of the ?n deterioration by absorbed carbon dioxide. ished retarder. 16. A set-stabilized gypsum plaster comprising 4. The process of claim 2 in which the carbona tion is carried out at superatmospheric pressure. 65 a set-accelerating material and a protein re tarder, the latter containing combined carbon 5. The process of producing a plaster retarder dioxide in an amount less than about 15 per cent comprising partially carbonating an alkaline, hy drolyzed, proteinaceous material by the addition by weight (dry basis) of the retarder. -17. A set-stabilized gypsum plaster composition of a water-soluble carbonate thereto in an amount to provide a carbonated retarder having a com 70 comprising a major portion of calcined gypsum bined carbon dioxide content of less than about 15 per cent by weight (dry basis). 6. The process of producing a plaster retarder comprising hydrolyzing a, protein material with an alkali, adding lime to the resulting mixture, 75 and a minor portion of a set-stabilizing composi tion which comprises an accelerator and a re tarder which has absorbed carbon dioxide. 18. A set-stabilized plaster comprising a major portion of calcined gypsum and a minor portion 2,412,156 3 . ‘of a' set-stabilizing composition which'com‘p'rises '20.'The gypsum plaster recited in claim’ 16 alum, lime and a keratinaceous retarder, which "latter has absorbed a form of carbon dioxide. wherein the combined carbon dioxide content of the'retarder constitutes between about 5 and 10 ‘ 19. The retarder recited in claim 14 wherein per cent by weight of the retarder. the carbon dioxide of the carbonate constitutes 5 between about 5 and 10 per cent by weight of the GEORGE D. KING. retarder. ' - ' Y» C. DAILEY.