Patent GB-387340-A (GB)
Title: Improvements in and relating to the manufacture of synthetic rubber
IPC: C08F36/18
Filed: 1931-07-24
Abstract: A product resembling rubber latex is prepared by polymerizing a halogen-2-butadiene-1 : 3 emulsified in an aqueous medium.  The halogenbutadiene may be emulsified by intensively mixing it, as such or in solution, with water containing an emulsifying agent, such as sodium or potassium oleate, triethanolamine oleate, sulphonated castor oil, sulphonated petroleum (sodium salt), soap, or magnesium linoleate; the emulsifying agent may be formed in situ, e.g. by mixing a solution of oleic acid in the halogenbutadiene with an aqueous solution of sodium hydroxide. Either component of the emulsion may form the external phase, but an emulsion in which water is the external phase is preferred. The emulsion may be homogenized, and is preferably rendered alkaline before, during or after polymerization.  The emulsified halogenbutadiene polymerizes spontaneously at atmospheric temperature and pressure, but the polymerization may be accelerated or retarded by the methods described in Specification 387,363 in connection with unemulsified halogenbutadienes.  Thus, polymerization may be accelerated by raising the temperature or pressure or by the action of light or by addition of a catalyst such as benzoyl peroxide or hydrogen peroxide, and may be retarded by addition of catechol, hydroquinone, pyrogallol, iodine, or phenyl-b -naphthylamine.  The polymerized emulsion may be used as such, or a rubber-like product may be obtained therefrom by evaporation or coagulation.  Thus, material such as cloth or paper may be impregnated with the polymerized emulsion and then dried, yielding waterproof products, or sheets, films and thin-walled articles may be prepared from the polymerized emulsion by removing water therefrom.  Incomplete polymerization of the emulsion yields a plastic, benzene-soluble product which resembles unvulcanized natural rubber and can be further polymerized by heat, e.g. after milling and moulding; complete polymerization of the emulsion yields an elastic, benzene-insoluble product resembling vulcanized rubber.  Solutions of the plastic product in solvents such as benzene, toluene, and carbon tetrachloride are useful as coating compositions or cements.  The products may be protected from oxidation by addition of anti-oxidants before or after polymerization; specified anti-oxidants are aromatic amines such as aniline, phenyl-b -naphthylamine, and diphenylethylenediamine, phenols such as p-hydroxydiphenyl and hydroquinone, and the anti-oxidants obtainable by extracting natural rubber with acetone. Substances capable of combining with acids, such as soda, caustic soda, zinc oxide and sodium oleate, also act as preservatives for the products.  The addition of protective colloids, proteins and resins to the emulsion before or after polymerization further improves the products; substances specified in this connection are glue, gelatin, casein, egg albumen, blood serum, milk serum, latex serum, pectins such as carragheen moss extract, Osage orange juice, gum arabic, gum tragacanth, and the resin obtainable from Guayule rubber by extraction with acetone.  Fillers, pigments, solvents, softeners and oils may also be added to the emulsion before or after polymerization.  In the examples, (1) chloro-2-butadiene-1 : 3 is emulsified in aqueous sodium oleate, and the emulsion is polymerized at about 30 DEG  C. and then allowed to evaporate in thin layers or coagulated with dilute acetic or other acid; (2) as in example 1, except that polymerization is effected at a lower temperature; (3) as in example 1, except that the emulsion is made alkaline with ammonia and polymerized under pressure; (4) as in example 1, except that the emulsion is made alkaline with ammonia; (5) as in example 2, except that sodium carbonate is added to the aqueous sodium oleate; (6) as in example 1, except that catechol is added to the halogenbutadiene; (7) as in example 1, except that iodine is added to the halogenbutadiene, and the emulsion rendered alkaline with ammonia; (8) a polymerized emulsion obtained as in example 2 is rendered alkaline with ammonia and then mixed with a suspension of phenyl-b -naphthylamine in aqueous sodium oleate; (9) chloro-2-butadiene-1 : 3 is added to a dilute aqueous solution of ammonia and sodium oleate, and the emulsion is polymerized by allowing it to stand at 0-10 DEG C.; (10) chloro-2-butadiene-1 : 3 and carbon black are stirred in the presence of a wetting agent, such as a sodium alkylnaphthalene sulphonate, and a little ammonia, and the resulting paste is dispersed in aqueous sodium oleate and allowed to stand; (11) zinc oxide is dispersed in water with the aid of isopropylnaphthalene sulphonic acid, and the dispersion is added to a polymerized emulsion prepared as in example 1; (12) an aqueous solution of glue rendered alkaline with ammonia is added to a polymerized emulsion prepared as in example 1, and a colloidal solution of a little phenyl-b -naphthylamine is added to the mixture; (13) a mixture of chloro-2-butadiene-1 : 3 and resin from Guayule rubber is emulsified and polymerized as in example 1, and then treated with ammonium hydroxide; (14) a mixture of chloro-2-butadiene-1 : 3 and xylene is emulsified and polymerized as in example 1; (15) an emulsion prepared and polymerized as in example 1 is treated in turn with xylene, ammonium hydroxide, and a colloidal suspension of phenyl-b -naphthylamine; (16) a mixture of chloro - 2 - butadiene - 1 : 3 and dibutyl phthalate is emulsified and polymerized as in example 1, and then treated in turn with ammonium, hydroxide and an aqueous suspension of phenyl-b -naphthylamine; cottonseed oil, mineral oil or spindle oil may be used instead of dibutyl phthalate; (17) a polymerized emulsion prepared as in example 1 is mixed with natural rubber latex, and the mixture is treated with ammonium hydroxide and phenyl-b -naphthylamine; (18) bromo-2-butadiene-1 : 3 is stirred into aqueous sodium oleate containing catechol, and the emulsion is polymerized by allowing it to stand.  Specification 387,325 also is referred to.ALSO:A product resembling rubber latex is prepared by polymerizing a halogen-2-butadiene-1 : 3 emulsified in an aqueous medium.  The halogenbutadiene may be emulsified by intensively mixing it, as such or in solution, with water containing an emulsifying agent, such as sodium or potassium oleate, triethanolamine oleate, sulphonated castor oil, sulphonated petroleum (sodium salt), soap, or magnesium linoleate; the emulsifying agent may be formed in situ, e.g. by mixing a solution of oleic acid in the halogenbutadiene with an aqueous solution of sodium hydroxide. Either component of the emulsion may form the external phase, but an emulsion in which water is the external phase is preferred. The emulsion may be homogenized, and is preferably rendered alkaline before, during, or after polymerization.  The products may be protected from oxidation by addition of anti-oxidants before or after polymerization; specified anti-oxidants are aromatic amines such as aniline, phenyl-b naphthylamine, and diphenylethylenediamine, phenols such as p-hydroxydiphenyl and hydroquinone, iodine, and the anti-oxidants obtainable by extracting natural rubber with acetone.  Substances capable of combining with acids, such as soda, caustic soda, zinc oxide and sodium oleate, also act as preservatives for the products. Protective colloids, proteins and resins may also be added to the emulsion before or after polymerization; substances specified in this connection are glue, gelatin, casein, egg albumen, blood serum, milk serum, latex serum, pectins such as carragheen moss extract, Osage orange juice, gum arabic, gum tragacanth, and the resin obtainable from Guayule rubber by extraction with acetone. Fillers, pigments, solvents, softeners and oils may also be added to the emulsion before or after polymerization.ALSO:A product resembling rubber latex is prepared by polymerizing a halogen-2-butadiene-1 : 3 emulsified in an aqueous medium.  The emulsified halogenbutadiene polymerizes spontaneously at atmospheric temperature and pressure, but the polymerization may be accelerated or retarded by the methods described in Specification 387,363 in connection with unemulsified halogenbutadienes.  Thus, polymerization may be accelerated by raising the temperature or pressure or by the action of light or by addition of a catalyst such as benzoyl peroxide or hydrogen peroxide, and may be retarded by addition of catechol, hydroquinone, pyrogallol, iodine, or phenyl-b -naphthylamine.  The polymerized emulsion may be used as such, or a rubber-like product may be obtained therefrom by evaporation or coagulation. Thus, material such as cloth or paper may be impregnated with the polymerized emulsion and then dried, yielding waterproof products, or sheets, films, and thin-walled articles may be prepared from the polymerized emulsion by removing water therefrom.  Incomplete polymerization of the emulsion yields a plastic, benzene-soluble product which resembles unvulcanized natural rubber and can be further polymerized by heat, e.g. after milling and moulding; complete polymerization of the emulsion yields an elastic, benzene-insoluble product resembling vulcanized rubber. Solutions of the plastic product in solvents such as benzene, toluene, and carbon tetrachloride are useful as coating compositions or cements.  The products may be protected from oxidation by addition of anti-oxidants before or after polymerization; specified anti-oxidants are aromatic amines such as aniline, phenyl-b -naphthylamine, and diphenylethyl-enediamine, phenols such as p-hydroxydiphenyl and hydroquinone, and the anti-oxidants obtainable by extracting natural rubber with acetone. Substances capable of combining with acids, such as soda, caustic soda, zinc oxide and sodium oleate, also act as preservatives for the products.  The addition of protective colloids, pr