Back to results
US 4,228,058 AGranted
Flame retardant latexes
AssigneeSyntex (U.S.A.) Inc.
InventorsRamchandra K. Hulyalkar, Rodrigue V. Lauzon
Life of this patent
Estimating the term…
Loading patent…
Loading patent…
AssigneeSyntex (U.S.A.) Inc.
InventorsRamchandra K. Hulyalkar, Rodrigue V. Lauzon
Estimating the term…
Flame retardant latex bases having an excellent balance of properties are prepared most efficiently and economically by blending together two separately polymerized latexes of different types, the polymeric content of one of said latexes being formed predominantly from a monomer mixture consisting of from about 70 to about 92% by weight vinylidene chloride and 8 to 30% by weight of certain polar comonomers principally of the lower alkyl acrylate class while the polymeric content of the second latex is formed from a monomer mixture consisting predominantly of styrene and butadiene. This technique of producing the desired flame retardant latex bases by combining two separately prepared but simpler component latexes not only maximizes quality control and manufacturing flexibility but also permits the simultaneous realization of higher conversions and reduced polymerization cycles or residence times so that productivity is also maximized. Provided the solids contents of the two separately polymerized latexes are fairly close to each other (i.e. somewhere near the usual range of about 40 to 50% by weight), then latex bases of commercial interest can be formed by blending the vinylidene chloride copolymer latex with from about 1/9th to about 4 times its weight of the styrene-butadiene latex so that vinylidene chloride represents from about 20 to 80% by weight of the total polymer content of the resultant blend.
A flame retardant latex base consisting essentially of a blend of two separately polymerized aqueous latexes each of which has a polymer content of at least about 35% by weight which in the first latex is a copolymer of which about 70 to 92% by weight is derived from vinylidene chloride with the balance being polar monomers which are predominantly lower alkyl esters of acrylic acids and in the second latex is a copolymer derived primarily from butadiene and styrene in weight proportions of between about 1 part butadiene to 9 parts styrene and about 2 parts butadiene to 1 part styrene, the proportion of said first latex comprising at least about 20% but not over about 90% by weight of said blend and sufficient to provide a vinylidene chloride content equivalent to between about 20 and 80% by weight of the total polymer content in said blend.
A method of preparing flame retardant latex bases comprising copolymerizing at temperatures predominantly between about 35.degree. and about 65.degree. C. vinylidene chloride and polar monomers which are predominantly lower alkyl esters of acrylic acids in an acidic aqueous emulsion with a redox-type, water soluble catalyst system comprising a free-radical generating initiator and an effective and compatible sulfoxy reducing agent promotor under conditions yielding a stable aqueous latex containing at least about 35% by weight of a resinous copolymer of which about 70 to 92% by weight represents vinylidene chloride, adjusting the pH of said latex to between about 4 and about 9 and blending same with at least about one ninth but not over about four times its weight of a stable aqueous latex having a pH of between about 5 and about 10 and containing at least about 35% by weight of a copolymer derived primarily from styrene and butadiene in weight proportions of between about 1 part butadiene to 9 parts styrene and 2 parts butadiene to 1 part styrene.
A method of preparing flame retardant latex bases comprising:
Dependencies are inferred from the claim text.