Process for making vinyl aromatic/allylic alcohol copolymers
AssigneeArco Chemical Technology, L.P.
InventorShao-Hua Guo
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Abstract
An improved process for making vinyl aromatic/allylic alcohol copolymers is disclosed. Gradual addition of a free-radical initiator during the course of the polymerization results in a substantial increase in the polymer yield obtained compared with the yield from conventional processes in which all of the free-radical initiator is charged initially. The process is particularly useful for making commercially important varieties of styrene-allyl alcohol copolymers.
Claims17
A process for making a vinyl aromatic/allylic alcohol copolymer, said process comprising:
- a) charging a reactor with an allylic alcohol, 10-30% of the total amount to be used of a vinyl aromatic monomer, and 45-75% of the total amount to be used of a free-radical initiator;
- b) heating the reaction mixture at a temperature within the range of about 125.degree. C. to about 185.degree. C., and
- c) gradually adding to the reaction mixture, at a decreasing rate, the remaining 70-90% of vinyl aromatic monomer and 25-55% of free-radical initiator, to produce a vinyl aromatic/allylic alcohol copolymer having a number average molecular weight within the range of about 800 to about 2000 and a hydroxyl number within the range of about 180 mg KOH/g to about 280 mg KOH/g;
- wherein the mole ratio of vinyl aromatic monomer to allylic alcohol used in the process is within the range of about 0.1 to about 0.5, and the yield of the copolymer is enhanced as a result of gradual addition of the free-radical initiator.
A process for making a styrene/allyl alcohol copolymer, said process comprising:
- a) charging a reactor with allyl alcohol, 10-30% of the total amount to be used of styrene, and 45-75% of the total amount to be used of a free-radical initiator;
- b) heating the reaction mixture at a temperature within the range of about 125.degree. C. to about 185.degree. C., and
- c) gradually adding to the reaction mixture, at a decreasing rate, the remaining 70-90% of styrene and 25-55% of free-radical initiator, to produce a styrene/allyl alcohol copolymer having a number average molecular weight within the range of about 1200 to about 1800 and a hydroxyl number within the range of about 180 mg KOH/g to about 220 mg KOH/g;
- wherein the mole ratio of styrene to allyl alcohol used in the process is within the range of about 0.3 to about 0.4, and the yield of the copolymer is enhanced as a result of gradual addition of the free-radical initiator.
A process for making a styrene/allyl alcohol copolymer, said process comprising:
- a) charging a reactor with allyl alcohol, 10-30% of the total amount to be used of styrene, and 45-75% of the total amount to be used of a free-radical initiator;
- b) heating the reaction mixture at a temperature within the range of about 125.degree. C. to about 185.degree. C., and
- c) gradually adding to the reaction mixture, at a decreasing rate, the remaining 70-90% of styrene and 25-55% of free-radical initiator, to produce a styrene/allyl alcohol copolymer having a number average molecular weight within the range of about 800 to about 1400 and a hydroxyl number within the range of about 240 mg KOH/g to about 280 mg KOH/g;
- wherein the mole ratio of styrene to allyl alcohol used in the process is within the range of about 0.15 to about 0.25, and the yield of the copolymer is enhanced as a result of gradual addition of styrene and free-radical initiator.
Dependencies are inferred from the claim text.