Патент USA US2117366код для вставки
"Patented May 177, ‘1933 “ I 2,117,366 . UNITED STATES PATEMMQFHGE,WM., -2,1\1':v,_36c ~ _ COATING MATERIAL HaroldF. Saunders and Charles Donald Downs, ’ Chicago, Ill., assignors to The Sherwin-Wil liams Company, Cleveland, Ohio,‘ a corporation 0f Ohio No ‘ Drawing. Application December 7, 1935, Serial No. 53,428 5 Claims. ‘ (Cl. 134-58) special interior ?nishes where bodied oils, treated This invention relates to the treatment of pig-, ‘ments and the like, and particularly to the neu oils, varnishes ‘and varnish gums are considered essential to obtain certain desirable effects in tralization-of the effect of adsorbed water thereon. On It is well known that a relatively high degree brushing, gloss or ?atness, ?lm hardness and the like. , From a theoretical standpoint, water which isv in the process known as “pulping” which com-. prises the replacement of water from an ‘aqueous retained adsorbed on ‘the surface of hydrophilic' suspension of the pigment,‘ such as is obtained in particles does not as such émulsify to form the of dehydration of‘ pigments may be accomplished phase of an. emulsion in the water-im precipitation, aqueous quenching, or other proc-‘. internal miscible liquid, but this internal phase consists ess operation, by a liquid substantially non-mis cible with water; and that in such pulping process of the combined pigment plus adsorbed water. elimination of water down to 0.5 to 2% of the "pulp” is the practical limit to which water is The apparent effect on the pulp is a shortness, or a short-?ow grainy-appearing paste. Further ‘removed. To eilfect as large a percentage ‘of re 15 placement as this, special agents are resorted to, agents previously mentioned does not change addition or retreatment with the usual treating‘ effect or appearance, since the vemulsion is which, by contact with the pigment, cause it to vthis already stabilized, and the water not far from wet preferentially in oil rather than water. Some‘ the natural solubility of water in the liquid, hence of the agents frequently used are drying oil fatty it cannot be removed or replaced and there is acids, soaps, sodium phosphate, borates, resi- ' no tendency for it to leave the pigment particle. 20 nates,_r_esins, amides or alcohols,'naphthenic acid, and the like. - . We havev discovered that when a substance ' such as lecithin, obtained from soya bean oil, or a modification of lecithin, obtained by heat Theoretically, complete replacement of water can be obtained; but this complete replacement is never reached in commercial practice, since ‘the pigment particles are frequently somewhat 2 coalesced into aggregates and thestreating agents ing, bleaching, purifying,_or otherwise-treating either soybean or other lecithin, is added to the ' pulp in- a“ small proportion. ' to 2.0%, a modi?cation of of approximately 0.5 the emulsion is ob are unable to reach the surfaces of the interior tained and, an immediate visible change takes particles of these aggregates. In addition, the ' place, the pulp becoming noticeably of a long, waterdmmisciblel liquids will in themselves re easy flow and losing the grainy appearance.- Fur .30 tain a certain percentage of water in a partially ther, when such pulp is_reduced with the afore 30 emulsi?ed condition. , _ ’ The. pigment dehydrated by a pulping process mentioned bodied oils, heat-treated oils, var possesses some very distinct advantages over the same pigment dehydratedby the customary pro-> a cedure of ?ltration and drying; since the latter introduces certain physical and chemical changes, disadvantageously a?ectlng color, opacity, tex nishes or varnish gums, which areintended to I be referred to in the claims by the expression “oil paint vehicle”, they are not curdled and their natural properties remain una?ected. vThe‘ ‘percentage of lecithin required is not critical. Partial effect, is obtained where, lower ture and‘ wettability.-_,;For this reason, the pulp _ percentages than specified are used, and a greater ing process of dehydration is commonly resorted to wherever the unavoidable presence of the small . amount of water is not considered harmful. Thus,,ior example, pulped white lead in lin seed oil, commonly referred to as “lead-in-oil” amount may e used, but since the desired result is obtained within the range speci?ed, any excess ' 40’ is merely wasted. The superior qualities of the pulped pigment, ‘such as ?ne texture and softness, a high degree is a- standard commercial article, its major use oi whiteness or color and markedly higher opac being for exterior house paints by further addi ' ity, are thus made available. tion of drying oils, thinners, and driers. ' The use of pulped pigments has not heretofore been practicable when further reduction was to be made with bodied oils, varnishes, natural or , synthetic gums, and the like, because the water present in the pulp produced a livering or clab beringgby change in the solubilities of these ma terials so that‘ they would leave solution and As an example of_ the practice of ‘this invention: . Two pounds of lecithin are added to 100 lbs. of a lithopone pulp carrying approximately 1%% 'of’ water and obtained by replacement of water from an aqueous suspension of lithopone by a liquid consisting essentially of 98%‘ mineral spirits and 1%%- linseed oil, and %% linseed oil fatty , Use of the zinc sulphideipigments, such as litho acids. "Thepaste thus made is stirred until the lecithin is well dispersed. An immediate reduc pone and similar high opacity pigments, in pulped form, has hitherto been limited since not only ‘ does the pulping of these pigments result in the cordance with our invention is shown by the curdlc. > . ,, - higher proportions‘of water, upwards of 1%, but 00' pigments are, in the main, utilized for , . tion or the short ?ow is apparent. , ‘as - The- supe'riorlty of this product made 'in ac following comparative tests: 1.‘ 1010 lbs. of lithopone, dried in the usual l‘a‘» 2. "12,117,866 I .1 v I _v v I‘ manner, ‘was made up into a ?at wall ?nish. with paint vehicle, a drier, pigment material and the usual ‘?at liquids. ' I p I I, 2. An attemptto make a ?at wag ?nish with lecithin, said pigment material comprising a “pulpedff pigment containing. a small percentage the same liquids as in No. fly/but usingpulped ‘ of water and the amount of the lecithin being I lithopone instead 91 the'dried ilthopone, ‘fail becauseagurdy’iiusteresulted.~ - _ . . between one-hair and two per cent, by weight, » \oasaid pigment. ' _ 3. A ?at wall ?nish was made with'the same v /lihuids as-in No. l and No. 2.but using lithopone in lecithin-treated'pulp form equivalent to only - , ZQAT‘eoating/ composition consisting of an oil paint vehiclermdrier. Pigment material and lecithin, said pigment material comprising "pu1ped” lithopone contamngq than two per 1. I. 910 lbs. olvlithopone onthe dry base. , On painting similar surfaces in the usual way . cent or water and the amount of .thin being with No. 1 and No. 3, not only was No. 3 whiter . between one-half and two per cent, by\weight,\ than No. 1 but it showed markedly greater cov- . of said‘ lithopone.v . ering power. A ll 3. A "pulped” pigment,‘ for coating composi _ The two paints were then carefully measured tions, having a water content 01' less than two 13 on an opacimeter using the Marten’s photometer ~ per cent and having incorporated therewith in a in accordance with the Bureau of Standards method in Technical Paper No. 306, dated Jan uary 16, 1926, where it was ‘found that whereas 10.5 lbs. of pigment in ‘No. 1 were required to bring 500 square feet of surface from black to a contrast'ratlo of 96, in the case of No. 3, only 8.94 lbs. of pigment were required for the same state or complete‘dispersion an amount of lecithin which is from one-half to two per cent, by weight, of the pigment. ‘ ‘ 4. A "pulped” lithopone having a water content oi‘ less than two per cent and having incorporated therewith in a state 01' complete ‘dispersion an amount of lecithin which is irom one-half to two per cent, by weight, of lithopone. 5. The herein described‘ method of improving 35 by ' the e diilerence two. methods per is, pound therefore: of lithopone prepa the covering power of an oil-emulsi?ed “pulped” for paints, having a water content not in Sq. ft. per lb.~ of pigment ‘ pigment excess of two per cent of the pigment, by weight, 30 ' black to 96 contrast ratio ularly dried lithopone__>_--_ ______ __"I____ 47.6 which consists in adding thereto and completely _. swing thus of the plant. cl ’ ii. w-w-i. our invention, what we is: coating compontion ~ no . of an oil dispersing therein an amount 01 lecithin which is from one-half. to two per cent, by weight, ' F. saummas.