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US 4,046,839 AGranted
Compositions having high impact at low rubber levels
AssigneeFoster Grant Co., Inc.
InventorStelvio Papetti
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AssigneeFoster Grant Co., Inc.
InventorStelvio Papetti
Estimating the term…
ABS polymers having improved physical properties are prepared by graft polymerizing, in an aqueous medium and in the presence of an effective amount of suspending agent and polymerization catalyst, styrene and acrylonitrile onto a butadiene polymer in the form of a latex, said butadiene polymer latex being characterized by a particle size of about 1000 to 3000 A, a gel content of about 20-85% by weight, and a swell index of about 18-150.
A process for graft polymerizing a mixture containing styrene and acrylonitrile onto polybutadiene in the form of a latex by effecting the polymerization in the presence of a catalyst and an effective amount of suspending agent wherein the improvement consists essentially of using a polybutadiene latex which has a particle size of about 1500-2500 A, a gel content of about 26-37 % by weight and a swell index of about 85-105.
A process for preparing a styrene-acrylontrile grafted polybutadiene polymeric composition, which composition consists essentially of about 12 to about 19% by weight polybutadiene based on the total weight of polymer in the composition and about 81 to about 88% by weight styrene-acrylonitrile copolymer based on the total polymer in the composition, said polymeric composition having an Izod Impact Strength in foot pounds per inch of notch determined by ASTM D-256 of at least about 8 and a ratio of Shear Stress at 868.sup.-1 second to Izod Impact Strength in foot pounds per inch of notch of less than about 4, by:
Dependencies are inferred from the claim text.
From the US filing history. Foreign family members aren’t listed.
On to polymers of conjugated dienes: vinyl aromatic monomers and nitriles as the only monomers
Synthetic resins or natural rubbers -- part of the class 520 series: polymer derived from nitrile, conjugated diene and aromatic co-monomers
Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
Technical subjects covered by former uspc cross-reference art collections [xracs] and digests
Term ended 6 Sep 1994 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
This invention relates to ABS-type polymers and more particularly to an improved process for preparing ABS-type polymers having excellent physical properties.
Over the past few years acrylonitrile-butadiene-styrene polymer, more commonly known as ABS polymers, have taken over a large share of the market formerly held by other impact polymeric materials such as impact polystyrene. The constantly increasing demand for these polymers is due to the excellent mechanical and chemical properties that they possess; for instance ABS plastics have greater toughness and impact strength than impact polystyrenes containing the same amounts of rubber and they also possess excellent chemical solvent resistance.
In spite of the excellent mechanical and chemical properties of ABS polymers their growth in the plastics market has been somewhat hindered due to disadvantages associated with the method of commercial production of ABS polymers. Today, by far the greatest amount of ABS polymer on the market is produced by conventional emulsion polymerization techniques. Unfortunately, the prolonged polymerization periods and multi-step post polymerization processing necessary in emulsion type processes often render products made by this type of process economically unsuitable for many producers. In addition, residual emulsifier and other agents still present in the polymer due to incomplete purfication cause some deterioration in the properties of the polymer. For these reasons more efficient and economical processes for producing ABS polymers having acceptable properties are constantly being sought.
ABS polymer is prepared as follows:
The apparatus for the polymerization consists of a five liter glass resin kettle equipped with steel head fitted with a thermometer a mechanical stirrer pressure gauge and gas inlet tube connected to a pressure release valve. Polymerization, with 20% solids, is conducted by charging the reactor with 3050 g of distilled water, 281 g of rubber latex (type indicated in Tables), 700 g of 2.5% solution of polyvinyl alcohol (0.45% by weight based on total water) and 100 g of 0.5% solution of polyethylene oxide (0.014% by weight polyethylene oxide based on total water). To this charge are added 521 g styrene, 211 g acrylonitrile, 3.5 g of antioxidant as a 10% solution by weight in acrylonitrile, and a solution of 1.8 g t-butyl peroxy pivalate, 0.54 g of t-butyl peroctoate and t-dodecyl mercaptan in an amount as indicated in the Tables in 25 g of styrene.
The reaction mixture is heated in an oil bath at 68.degree. C. for 4 hours and at 100.degree. C. for 1 hour. The mixture is agitated during heating. The reaction product is separated in the form of beads and washed with water in a stainless steel screen basket and dried.