PROCESS FOR PREPARING LOW SULFUR DISPERSANT POLYMERS

摘要

The present invention relates to a process for preparing grafted polyalkyl(meth)acrylates (PAMAs) containing dispersant repeating units in the polymer backbone as well as in the grafted layer, which polymers are characterized by a low sulfur content, the products available by this process and their use as an additive to fuels, especially to middle distillates and blends thereof. The present invention further relates to a composition comprising the grafted polyalkyl(meth)acrylates prepared by the process according to the present invention and the use of said composition as an additive component to fuels, especially to middle distillates and blends thereof, and for improving the cold flow properties of fuel oil and fuel oil compositions, especially to middle distillate fuels and blends thereof.

主权项

1. A process for preparing a grafted polyalkyl (meth)acrylate copolymer (A), comprising a polymer backbone comprising the following monomers units (A1) to (A4):
(A1) 0% to 40% by weight of one or more ethylenically unsaturated ester compounds of formula (I) whereinR is H or CH3,R1 represents a linear or branched, saturated or unsaturated alkyl group with 1 to 5 carbon atoms or a cycloalkyl group with 3 to 5 carbon atoms,R2 and R3 independently represent H or a group of the formula —COOR′, wherein R′ is H or a linear or branched, saturated or unsaturated alkyl group with 1 to 5 carbon atoms or a cycloalkyl group with 3 to 5 carbon atoms, (A2) 20% to 93.5% by weight of one or more ethylenically unsaturated ester compounds of formula (II) whereinR is H or CH3,R4 represents a linear or branched, saturated or unsaturated alkyl group with 6 to 15 carbon atoms,R5 and R6 independently represent H or a group of the formula —COOR″, wherein R″ is H or a linear or branched, saturated or unsaturated alkyl group with 6 to 15 carbon atoms, (A3) 5% to 60% by weight of one or more ethylenically unsaturated ester compounds of formula (III) whereinR is H or CH3,R7 represents a linear or branched, saturated or unsaturated alkyl group with 16 to 30 carbon atoms,R8 and R9 independently represent H or a group of the formula —COOR′″ wherein R′″ is H or a linear or branched, saturated or unsaturated alkyl group with 16 to 30 carbon atoms, and (A4) 1% to 40% by weight of at least one N-dispersant monomer selected from the group consisting of vinyl pyridine, N-vinyl imidazole, N-vinyl pyrrolidone (NVP), morpholinoethyl methacrylate, N-vinyl caprolactam, N,N-dimethylaminoethyl methacrylate (DMAEMA), tert-butyl aminoethyl methacrylate, N,N-dimethylaminopropylmethacrylamide (DMAPMAm), dimethylaminopropylacrylamide and dimethylaminoethylacrylamide, wherein components (A1) to (A4) add up to 100% by weight based on the total weight of the polymer backbone; and (A5) 0.5% to 10% by weight of a monomer unit, which is grafted on the polymer backbone, consisting of at least one N-dispersant monomer selected from the group consisting of vinyl pyridine, N-vinyl imidazole, N-vinyl pyrrolidone (NVP), morpholinoethyl methacrylate, N-vinyl caprolactam, N,N-dimethylaminoethyl methacrylate (DMAEMA), tert-butyl aminoethyl methacrylate, N,N-dimethylaminopropylmethacrylamide (DMAPMAm), dimethylaminopropylacrylamide and dimethylaminoethylacrylamide, based on the total weight of grafted polyalkyl(meth)acrylate copolymer (A), the process comprising the steps of: (a) charging a mineral oil to a reaction vessel; (b) preparing a monomer mixture of monomer units (A1) to (A4) as hereinbefore described and a first reaction initiator; (c) adding the mixture as prepared under step (b) to the mineral oil of step (a), preferably over the course of 1 to 5 hours, more preferably over the course of 2 to 3 hours; (d) polymerizing the mixture as obtained under step (c), preferably in the absence of any chain transfer agent; (e) optionally isolating the polymer as obtained under step (c); (f) adding monomer units (A5) as hereinbefore described; (g) adding a second reaction initiator; (h) polymerizing the mixture as obtained under step (g); (i) optionally isolating the polymer as obtained under step (h); and/or (j) diluting the polymer mixture as obtained under step (h) or the isolated polymer obtained under step (i) with a mineral oil to achieve the desired concentration of polymer in oil.