Patented Nov. 5, 1946 . ' , ' 2,410,775 UNITED STATES PATENT OFFICE COLOR STABILIZATION OF VINYL HALIDE RESINS Fred W. Cox, Cuyahoga Falls, and James M. Wallace, Jr., Akron, Ohio, assignors to Wing foot Corporation, Akron, Ohio, a corporation of Delaware 1 No Drawing. Application June 22, 1945, . 1 Serial No. 601,060 9 Claims. (01. 2s0_7s) This invention relates to the stabilization of though any other salt of amino-guanidine may vinyl halide resins, and particularly the vinyl be used. The quantity of stabilizer used will halide resins which are polymers of» at least 70 depend upon the conditions of heating to which percent of vinyl halide, including the polymers the vinyl resin is to be subjected. If only mild of 100 percent vinyl halide and the copolymers 5 heating is encountered, small amounts or even of vinyl halides with other polymerizable monotraces of the agent will yield an improved prod ole?m‘c compounds. uct. Although the incorporation of from 0.05 to ‘.‘inyl halide resins generally will discolor when 10 percent by weight, based on the polymer con heated, for example at a temperature of 100° tent of the resin, will produce useful composi C. or higher, and especially in the presence. of 10 .tions, generally the best results are obtained iron or iron salts. It has been discovered that from the use of from 0.5 to 5 percent of the the addition of a small proportion of aminoguanidine or salt thereof. guanidine or a salt of amino-guanidine will enThe stabilizing agent may be incorporated by able the resin to resist the discoloration e?’ect any of several methods. It may be added to I for substantial periods of time.~ 15 the solid resin and mixed therein by means of a The vinyl halide resins which may be stabilroll mill or other mixing machine adapted to ized in accordance with this invention include the blend solid plastic materials. The ,mixing ma polyvinyl halides, made by the polymerization chine may be heated during the mixing oper of any compound of the group consisting of ation to render the compositions more plastic. vinyl chloride, vinyl bromide, vinyl ?uoride and 20 Alternatively, the stabilizing agent may be dis vinyl iodide without the presence of other polysolved in any suitable solvent and the solution merizable mono-ole?nic compounds. The inven~ then mixed with the resin. The vinyl halide tion is also useful in the prevention of discolorresin may be dissolved in a solvent, such as ation upon heating in copolymers of from 70 to ethylene dichloride, and the stabilizing agent 100 percent of a vinyl halide with from 0 to 30 25 added to the solution and dispersed therein by ‘percent of another polymerizable mono-ole?nic means of any stirring device. If the polymers compound. Although any polymerizable monoor copolymers are prepared by polymerization in ole?nic compound which is compatible with the an aqueous emulsion, the stabilizing. agent may Vinyl halide in polymeric form, i. 8-, which forms be added and distributed through the polymer copolymers therewith, may be stabilized, the in- 30 prior to coagulation. Any other method which vention is particularly Useful in the treatment Of permits a uniform distribution of the stabilizing copolymers of monomeric mixtures of vinyl halide agent throughout the polymer may be used. and up to 30 percent of Vinyl acetate, vinylidene The stabilized resins may be used in theprepa chloride, Styrene, the alkyl fumarates, the alkyl ration of cast ?lms or in the fabrication of maleates. the alkyl chloromaleates, the alkyl 35 molded or extruded shapes, which uses are well chlorofumarateathe alkylacrylates. or the alpha known to the art. The stabilized vinyl halide ' substituted alkyl acrylates. The copolymers resins are particularly useful in the preparation which are of particular importance are those of of transparent or light colored articles in which 70 to 98 percent of vinyl halide and from 2 to 30 discoloration upon heating is undesirable. percent of said other mono-ole?nic monomer- A 40 preferred class of copolymers are those of 80 to 95 percent of vinyl halide and from 5 to 20 percent of the other monomer. Further details of the invention are set forth with respect to the following speci?c examples. Exam le 1 p ' a The stabilization against discoloration upon Each of three 10 gram samples of a copolymer of heating is e?ected by the incorporation of amino- 45 90 percent vinyl chloride and 10 percent diethyl guanidine or any salt of amino-guanidine. For fumarate were milled with 2 ml. of dibutyl seba obvious economic reasons the most useful salts ‘cate. Two of these samples were blended'respec of amino-guanidine are those made by the retively with 0.2 gram of amino-guanidine sulfate action of amino-guanidine with inexpensive readand with 0.2 gram of guanidine sulfate. The ily available acids. Thus, the most useful salts 50 third sample wasused as a control for the pur are the hydrochloride of amino-guanidine, the pose ofcomparison. The copolymer samples were bicarbonate of amino-guanidine, amino-guanidine sulfate, amino-guanidine nitrate, aminoguanidine acetate, amino-guanidine carbonate, and the hydrosulfate of amino-guanidine, al- 55 milled separately on a laboratory-size chromium plated roll mill for 5 minutes at 140° F. and then for 5 minutes at 212° F. The copolymers were rolled into sheets 1 mm. in thickness and Spegi 2,410,775 3 4 mens were cut therefrom for heat stability tests. The specimens were introduced into an oven heated at 135° C. and every half hour for 4 hours discoloration upon heating which comprises a co~ polymer of 70 to 98 percent of vinyl chloride and 2 to 30 percent of diethyl fumarate, said resin containing from 0.05120 10 percent by weight based one of each type was withdrawn. It was found that the copolymer containing amino-guanidine on the polymer content, of a salt of amino-guani dine. sulfate was stabilized to the e?ect of the ele 4. A vinyl chloride resin capable of resisting vated temperature, while the copolymer contain discoloration upon heating which comprises a ing guanidine sulfate and the control specimen copolymer of 80 to 95 percent of vinyl chloride containing no modifying agent were discolored to 10 and 5 to 20 percent of diethyl fumarate, said resin about the same extent. containing from 0.05 to 10 percent by weight based Example 2 on the polymer content, of amino-guanidine. Using the procedure described in Example 1 i 5. A vinyl chloride resin capable of resisting the same copolymer was blended with 2 percent discoloration upon heating which comprises a of amino-guanidine bicarbonate and another copolymer of 80 to 95 percent of vinyl chloride sample with guanidine carbonate. The effect of and 5 to 20 percent of diethyl fumarate, said resin containing from 0.05 to 10 percent by weight the addition of these modifying agents upon the heat stability of the copolymer was determined based on the polymer content, of a salt of amino guanidine. , in the manner described in Example 1. After 6. A vinyl chloride resin capable of resisting one hour of heating at 135° C. the specimen con 20 taining guanidine carbonate was discolored even discoloration upon heating which comprises a copolymer/of 70 to 98 percent of vinyl chloride more than the control specimen, containing, no modifying agent, while the specimen containing and 2 to 30 percent of diethyl fumarate, said resin containing from 0.5 to 5 percent by weight 25 based on the polymer content, of amino-guani This application is a continuation-in-part of dine. 7. A vinyl chloride resin capable of resisting application Serial No. 502,314 ?led September 14, discoloration upon heating which comprises a 1943. copolymer of '70 to 98 percent of vinyl chloride Although the invention has been described with respect to speci?c examples, it is not intended 30 and 2 to 30 percent of diethyl fumarate, said resin containing from 0.5 to 5 percent by weight that the details thereof shall be construed as lim based on the polymer content, of a salt of amino itations upon the scope of the invention except guanidine. to the extent incorporated in the following claims. 8. A vinyl chloride resin capable of resisting We claim: discoloration upon heating which comprises a 1. A vinyl halide resin capable of resisting dis copolymer of 80 to 95 percent of vinyl chloride coloration upon heating which comprises a poly and 5 to 20 percent of diethyl fumarate, said mer of from 70 to 100 percent of a vinyl halide resin containing from 0.5 to 5 percent by weight and up to 30 percent of another polymerizable based on the polymer content, of amino-guani 'mono-ole?nic compound, said resin containing from 0.05 to 10 percent by weight based on the 40 dine. 9. A vinyl chloride resin capable of resisting polymer content, of a compound of the group discoloration upon heating which comprises a consisting of amino-guanidine and salts of amino copolymer of 80 to 95 percent of vinyl chloride guanidine. and 5 to 20 percent of diethyl fumarate, said 2. A vinyl chloride resin capable of resisting discoloration upon heating which comprises a co 45 resin containing from 0.5 to 5 percent by weight amino-guanidine bicarbonate was in perfect con dition. based on the polymer content, of a salt of amino polymer of '10 to 98 percent of vinyl chloride and guanidine. 2 to 30 percent of diethyl fumarate, said resin containing from 0.05 to 10 percent by weight based FRED W. COX. on the polymer content, of amino-guanidine. 3. A vinyl chloride resin capable of resisting 50 JAMES M. WALLACE, JR.