The Goodyear & Tire Rubber Company

Edwin Reed Dunn

Gary Lee Burroway

The growth of bacteria in latex is an age old problem. To control the growth of bacteria in latex, chemical bactericides are often added to latex. This invention discloses a technique for providing latex with resistance to bacterial growth. It is based upon the discovery that ions of a metal from Group Ib of the Periodic Chart, such as copper, silver, or gold, will provide latex with resistance to bacterial growth. The subject invention more specifically discloses a latex which is comprised of (1) a polymer, (2) water, (3) an emulsifier and (4) ions of a metal from Group Ib of the Periodic Chart. In most cases, the metal ions will be present in an amount which is within the range of about 1 ppm to about 50 ppm. As a general rule, silver ions are preferred. By utilizing a combination of standard organic chemical bactericides and Group Ib metal ions, the level of chemical bactericides and metal ions needed to satisfactorily control bacteria growth can be significantly reduced. Such a combination of chemical bactericides and Group Ib metal ions accordingly offers excellent cost advantages and provides treated latex with a high degree of protection against bacterial growth. The present invention further reveals a latex which is comprised of (1) a polymer, (2) water, (3) an emulsifier, (4) ions of a metal from Group Ib of the Periodic Chart and (5) an organic chemical bactericide.

Latex with resistance to bacterial growth

The present invention is based upon the discovery that composite open-cell foam structures, such as carpet underlay cushions, having improved compression resistance and better wear characteristics can be manufactured by utilizing a carboxylated styrene-butadiene rubber latex which is comprised of a styrene-butadiene rubber latex and a carboxylated styrene-butadiene rubber latex. The subject invention more specifically discloses a carpet underlay cushion structure comprising: a carrier layer of open-cell, resilient polyurethane foam material, said resilient foam material being substantially completely and uniformly impregnated with a carboxylated styrene-butadiene rubber latex blend, wherein said carboxylated styrene-butadiene rubber latex blend is comprised of (a) about 70 weight percent to about 95 weight percent of a styrene-butadiene rubber latex and (b) from about 5 weight percent to about 30 weight percent of a carboxylated styrene-butadiene rubber latex; the impregnated foam material being dried after said impregnation to produce a foamed, open-cell, resilient composite cushion structure wherein the open cells thereof partially comprise said carrier layer of polyurethane foam material.

Foam structure

By utilizing the process of this invention, nitrile rubber latices having solids contents of greater than 60 percent can be prepared from standard nitrile rubber latices having solids contents of less than 30 percent. The present invention more specifically discloses a process for increasing the solids content of a low solids nitrile rubber latex which comprises the steps of (1) concentrating the low solids nitrile rubber latex by removal of water therefrom to produce an intermediate solids nitrile rubber latex having a solids content which is within the range of about 35 percent to about 45 percent, wherein the low solids nitrile rubber latex has a solids content which is less than about 30 percent; (2) subjecting the intermediate solids nitrile rubber latex to a pressure which is within the range of about 3.45.times.10.sup.6 Pa to about 6.9.times.10.sup.7 Pa at a temperature which is within the range of about 120.degree. F. to about 170.degree. F. to produce a pressure agglomerated nitrile rubber latex; and (3) further concentrating the pressure agglomerated nitrile rubber latex by removal of water therefrom to produce a high solids nitrile rubber latex having a solids content of greater than about 60 percent.

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Rocky Face, GA, United States of America

Edwin Reed Dunn