US 2445994 A
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Patented July 27, 1948 NT oFFIcE TOY L Ellen Gay Beiisonand Richard Ernest Benson, 3 3 Eden, N.Y.
No Drawing. Application September 6, 19 14 Serial N0. 552,938
This invention is concerned with a new toy possessing entertaining characteristics and features, said characteristics being well-known in principle to the chemist but which are Very amusing and absorbing to the tiny tots of 2 to 5 years of age and Which because of the unique and apparently mysterious nature of said characteristics is enjoyed not only by the older, children ;but also bythe grown-ups.
The ,object of our invention is to provide an "improved toy in the form of a cotton washcloth for the amusement of people of all ages but particularly for the entertainment of children by utilizing certain dyes that have the ability to change color when exposed to a differential of pH, defined as hydrogen ion concentration.
We have accomplished this by employing the well-known phenomenon of the change of color of certain dyes known to the chemist by the general name of indicators.
Fundamentally our invention is a toy which is formed by printing, spraying, or otherwise supporting upon a cotton washcloth, Curcumin having the formula 2.C'H3OCsH3-1--OH--4-CH CHCO) 2CH2 or Brilliant Yellow having the formula .(4--HOC6H4N2NCsHsSOsNEtCHI 2 or a combination of these dyes and which possess one color when in contact with soap which is different from the respective colors whicheach possessses in the absence of said soap.
The simplest toy consists of a cotton wash cloth having a restricted portion dyed with a dilute solution of brilliant yellow to give a cloth having a pictorial design of yellow color. When this cloth is wet and any of the popular brands of commercial grades of fatty acid toilet or face soaps applied, the pictorial design on the washcloth turns vivid pink. When the soap is rinsed out, the original yellow color returns. Among the designs that we have employed are those of animals and familiar household objects.
Brillian Yellow and Curcumin have been found to be the most satisfactory for printing onto cotton fabric because of their ease of printing and affinity for this textile.
The toy is even more intriguing when both of the above indicator dyes are partially or wholly superimposed on one another or when prints involving two or more dyes are employed to produce the desired design. For example, design of a leopard can be printed with Brilliant Yellow and its spots can be printed with Curcumin in a two pass operation. Though both of these dyes are yellow. the spots are plainly visible unlessextreme care is taken to print the spots lightly.
When the dampened washcloth is rubbed with soap, the printed leopard turns pink except for the spots which turn a brownish-lavender; The exact shade of the spots is a composite of pink and amber and depends upon the relative amounts of the two dyes employed in the printing of the toy. Naturally the two dyes can be reversed with the spots being printed with Brilliant Yellow. Also by suitable printing technique, one dye is not applied over the other.
It is also to be understood that the fabric does not necessarily have to be white. Rather startling effects are produced when the dye, particularly Brilliant Yellow is printed upon a yellow washcloth and an unsuspecting male starts to wipe shaving soap from his face. Also beautiful effects can be obtained by employing fabric on which conventional dyes have already been printed.
Indicators are well -known to all those who have more than an elementary training in chemistry. One class include oxidation-reduction indicators. These are not included in this invention. Another class of indicators include those compounds which change color when subjected to a suflicient change in pH. However all indicators in this classification are not operative in our invention because this invention being a toy is limited to that range of pH to which a child may safely be exposed. We propose to limit the upper pH to that Produced by commercial grades of toilet and laundry soap sold to the domestic trade, particularly the housewife. This pH range is generally 9 to 11. Therefore, by the above, we have limited our invention to Curcumin and Brilliant Yellow which change color when subjected to a change in pH said change being confined within the limits of that normally encountered in municip-al drinking water namely, from about 6.0 to 8.5, and that produced by a commercial toilet or face soap. Our invention is a toy in the form of a cotton washcloth or the like having Curcumin or Brilliant Yellow dye covering a restricted portion thereof to provide a. pictorial representation thereon, said indicator dyes changing in color within the range of pH of drinking water and that pH produced by a commercial soap; said toy when wet changing colors upon the application of soap and regaining its original appearance when the soap is removed by rinsing with water; and said toy being further characterized by being fast when subjected to repeated rubbing 1. A toy washcloth or the like, comprising a piece of cotton fabric and a dye selected from a group composed of Curcumin having the formula" (2 CH3OCtI-Iz-1O-H4 CH :CHCO)'2CH2 and Brilliant Yellow having the formula (4 Hoc6H4N:nosmsomacaz 2' covering a restricted portion of said piece of cotton fabric to provide a pictorial representation thereon, said dye being characterized by changing in color when contactedwith a solution of a fatty acid soap having a pH of from 90 co-1'1 andby substantially" reverting to it's originalco'lor' when thereafter rinsed with water having/a: pH of from 6;0' to' 815, and said' dye also having anv affinity for said piece'of cottonfabri'c to withstand repeated r'ubb-in'gs, washings and rinsings'.
2. A toy" washcloth or' the like comprising a piece of'cotton fabric and 'Curcumin and Brilliant 4 I r' f, 1 Yellow dyes having a, formula, respectively, of
(2CH3OC6H31-OH4CH 2 CHCO) 20H:
and v (4HOC6H4N I NCsHsSOaNaCH: 2
covering a restricted portion of said piece of cotton fabric jointly to provide a pictorial representation thereon, both of said dy's being characterized by changing in color when contacted with a solution of a fatty acid soap having a pH of from 9.0 to 11 and by substantially reverting to their original color when thereafter rinsed with water having ap-H of from 6.0 to 8.5, and said dyes also having an affinity for said piece of cotton fabric to withstand repeated rubbings, washings and rinsings. I
ELLEN GAY BENSON. RICHARD ERNEST BENSON.
REFERENCES CITED The following references are of record iii Elie file of thi's patent:
UNITED' STATES PATENTS Number Name Date;
1,9335'43 Sanburn ec: 5', 1-933 2;129,995 Dreyfus sent. 1,3;1'93 2,229,155 Wenker' Jan. 2;,1941 2,250,980 Workman my; 29; 1941