Soil release agents having allyl-derived sulfonated end caps

In a process for preparing sulfonated ester compositions useful as functional materials in detergent compositions, said process comprising at least one ester-bond forming procedure and at least one sulfonation procedure, the improvement whereby a particular terminally sulfonated, substantially linear co-oligomeric ester composition is secured without reliance upon a chlorinated compound and without reliance upon a procedure comprising a sulfonation step followed by an ethoxylation step;

• which improvement comprises the ordered sequence of:
• (a) in an ester-bond forming procedure, a transesterification step, comprising reacting a mixture of
• (I) about 2 moles of allyl alcohol ethoxylated to an average degree of polymerization of from about 8 to about 20;
• together with
• (II) from about 2 to about 7 moles of dimethyl terephthalate;
• and
• (III) from about 2 to about 14 moles of a C.sub.2 -C.sub.4 glycol;
• in the presence of a conventional transesterification catalyst;
• at a transesterification temperature in the range from about 120.degree. C. to about 250.degree. C., at a transesterification pressure in the range from about 0.75 atm. to about 3 atm. and for a transesterification time of from about 2 hrs. to about 60 hrs.;
• followed by an oligomerization step comprising further reacting said mixture at an oligomerization temperature in the range from about 170.degree. C. to about 250.degree. C., at an oligomerization pressure in the range from about 1.times.10.sup.-6 atm. to about 0.5 atm., and for an oligomerization time of from about 2 hrs. to about 60 hrs.;
• thereby producing an allyl endcapped co-oligomeric ester precursor;
• and
• (b) in a radical-initiated olefin sulfonation procedure, at least one step of sulfonating said allyl end-capped co-oligomeric ester precursor, in the presence of water, with a low temperature, free-radical sulfonation initiator and a conventional bisulfite sulfonating reagent;
• wherein the reactants are effectively cocontacted in an aqueous reaction mixture and wherein the level of said conventional bisulfite sulfonating agent is from about 1 mole to about 4 moles per mole of said allyl end-capped co-oligomeric ester precursor and wherein the following sulfonation conditions are respected:
• sulfonation temperature:
• in the range from about 0.degree. C. to about 100.degree. C.;
• sulfonation pressure:
• in the range from about 0.5 atm. to about 3 atm.;
• and sulfonation time period:
• from about 0.1 hrs. to about 90 hrs.

A sulfonated oligomeric ester composition, in a sodium salt form, consisting essentially of:

• (i) a substantially linear oligomeric ester backbone, which is comprised of terephthaloyl and oxyalkyleneoxy repeat units, wherein from about 85% to 100% by weight of said backbone is comprised of terephthaloyl and oxy-1,2-propyleneoxy repeat units;
• and
• (ii) terminal moieties covalently attached to said backbone, wherein said terminal moieties are derived from compounds selected from the group consisting of allyl alcohol ethoxylate, dimethylterephthalate, and 1,2-propylene diol, provided that from about 70% to 100% of said terminal moieties are selected from the group consisting of:
• --(E.sub.n)--(CH.sub.2 --CH{SO.sub.3 N.sub.a }--CH.sub.2 {SO.sub.3 Na}),
• --(E.sub.n)--(CH.sub.2 --CH{SO.sub.2 Na}--CH.sub.2 {SO.sub.3 Na}), and
• --(E.sub.n)--(CH.sub.2 --CH.sub.2 --CH.sub.2 {SO.sub.3 Na});
• wherein (E.sub.n) is poly(oxyethylene)oxy and n is in the range from about 8 to about 20;
• and wherein said composition comprises from about 5% to about 40%, by weight, of end-cap moieties --(CH.sub.2 --CH{SO.sub.3 Na}--CH.sub.2 {SO.sub.3 Na}), --(CH.sub.2 --CH{SO.sub.2 N.sub.a })--CH.sub.2 (SO.sub.3 Na}) and --(CH.sub.2 --CH.sub.2 --CH.sub.2 (SO.sub.3 N.sub.a }).