TH69977A - Dosperoxide is also a suspension process. Where styrene is polymerized - Google Patents

Abstract

DC60 (02/07/47) The invention relates to the suspension polymerization process for the preparation of styrene-containing (co)polymers, in which the process involves a continuous or semi-continuous dosing step of an initiator into a reaction mixture, where the initiator has a specific half-life at the temperature of the reaction mixture at which it is dosed. The invention also relates to the styrene-based (co)polymers obtained by such process, and to the use of such styrene (co)polymers in the molding process. The invention relates to the suspension polymerization process for the preparation of styrene-containing (co)polymers, in which the process involves a continuous or semi-continuous dosing step of an initiator into a reaction mixture, where the initiator has a specific half-life at the temperature of the reaction mixture at which it is dosed. The invention also relates to the styrene-based (co)polymers obtained by such process, and to the use of such styrene (co)polymers in the molding process.

Claims (13)

1. A vinyl chloride-free suspension polymerization process for polymerizing styrene monomers, or mixtures of styrene-containing monomers, involves a continuous or semi-continuous dosing of an initiator into the reaction mixture at a polymerization temperature, characterized by at least one dosed initiator having a half-life of 60 minutes or less at that polymerization temperature. 2. The process under claim 1 in which the mixture is further composed of co-monomers selected from groups consisting of vinyl acetate, ethylene, propylene, acrylonitrile, butadiene, (meth)acrylate, and unsaturated polymers that are or are similar to ethylene, such as polybutadiene and styrene-butadiene rubber. 3. The process under claim 1 or 2 where the aforementioned initiator is continuously or semi-continuously dosed from a point in time where at least 1%, the required minimum of 0.5%, the more required minimum of 0.1%, the most required is no monomers have been polymerized until at least 70%, the required minimum of 80%, the more required minimum of 90%, and the most required is all of the monomers have been polymerized. The phrase "all of the monomers have been polymerized" means that less than 1,000 parts per million of monomers are present in the final polymerized product. 4. Any of the procedures under Claim 1-3, in which an initiator is selected from a group comprising peroxydicarbonate, peroxycarbonate, peroxyester, peroxyketal, diacyl peroxide, dialkyl peroxide, ketone peroxide, azo initiators, each of which may contain one, two, or more -OO-, and/or -NN- fractions in each molecule, and each of which is further functionally achievable by an amine, phosphate, ester, ether, or alcohol fraction, and a mixture thereof; such initiator should be Select from the group containing replaced, or unreplaced, of dibenzoyl peroxide, 1,1-di(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 2,2,-di(tert-butylperoxy)butane, 1,1-di(tert-butylperoxy)cyclohexane, azo initiators, and their mixtures, most preferred from dibenzoyl peroxide, 1,1-di(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2-methylbutyronitrile), and their mixtures. 5. Any of the processes under Claims 1-4 where the reaction temperature is 170°C or lower, required 150°C or lower, required above 130°C or lower, and required maximum 120°C or lower. 6. Any procedure under any of the claims 1-5 in which at least a portion of the initiator is continuously or semi-continuously dosed for a period of at least 0.5 hours, with a minimum requirement of 1 hour. 7. Any of the processes under Rights 1-6 that use at least 0.01% by weight, preferably at least 0.05% by weight, and preferably at least 0.1% by weight of the total weight of all starting materials, and preferably a maximum of 5% by weight, preferably a maximum of 3% by weight, and preferably a maximum of 1% by weight of the total weight of all starting materials, relative to the weight of the monomers to be polymerized. 8. Any of the procedures under Rights 1-7 where a blowing agent is added or dosed into the reaction mixture when the polymerization level of the monomer is less than 80%, required less than 60%, or maximum required less than 50%. 9. Any of the procedures under Rights 1-8 where the initiator, or a mixture of initiators, is dosed in the form of, should be used is aquatic dispersion. 10. Any of the procedures under Rights 1-9 in which an added initiator is used to reduce the remaining monomer levels. 11. The process under claim 10 for the preparation of expandable polystyrene. 12. A (co)polymer derived from styrene can be obtained by any of the processes described in Patents 1-11, whereby the (co)polymer derived from styrene has less than 50 ppm of starting material remaining, less than 40 ppm of the required amount, and less than 25 ppm of the required minimum starting material, immediately following 1 hour of drying at 60 °C and sieving. 13. Use of styrene (co)polymer under claim 12 in molding processes involving heating the co(polymer) to prepare foam products.