Abstract:
A method for preparing resinous polymodal monovinylarene-conjugated diene block copolymers and polymers produced thereby are provided. The method comprises sequentially contacting under polymerization conditions:
(a) a monovinylarene monomer and initiator; (b) initiator and a monovinylarene monomer; (c) a sequence of at least two charges selected from the group consisting of (i) initiator and a monovinylarene monomer, (ii) a mixture of monovinylarene monomer and conjugated diene monomer, (iii) a conjugated diene monomer, (iv) a monovinylarene monomer; (d) a coupling agent; wherein the sequence of at least two charges in step (c) can be made in any order. In a preferred embodiment, at least three initiator charges are provided. In another preferred embodiment, at least three monovinylarene charges precede the first charge containing conjugated diene. In another preferred embodiment, at least four monovinylarene charges precede the first charge containing conjugated diene.
Abstract:
A method of preparing a polymer under solution polymerization conditions in a reaction zone comprising: (a) charging a monovinylaromatic monomer and an initiator in the presence of a randomizer; thereafter (b) charging an initiator and a monovinylaromatic monomer; thereafter (c) charging a mixture of a monovinylaromatic monomer and conjugated diene monomer; thereafter (d) optionally charging a mixture of monovinylaromatic monomer and conjugated diene monomer; and thereafter (e) charging the reaction mixture with a coupling agent, wherein in each of steps (a) and (d) polymerization is conducted until essentially no free monomer is present.
Abstract:
A method for preparing tapered block copolymers in a polymerization process by sequentially charging: (1) an initiator and monovinylaromatic monomer in the presence of a randomizer; (2) an initiator and monovinylaromatic monomer; (3) a mixture of monovinylaromatic and conjugated diene monomers; (4) a mixture of monovinylaromatic and conjugated diene monomers; (5) conjugated diene monomer; and (6) a coupling agent; and the polymodal tapered block copolymers prepared thereby. The copolymers are particularly useful neat or in blends for applications such as packaging and food or drink containers which require transparency and good environmental stress crack resistance.
Abstract:
A method of preparing a polymer under solution polymerization conditions in a reaction zone comprising: (a) charging a monovinylaromatic monomer and an initiator in the presence of a randomizer; thereafter (b) charging an initiator and a monovinylaromatic monomer; thereafter (c) charging a mixture of a monovinylaromatic monomer and conjugated diene monomer; thereafter (d) optionally charging a mixture of monovinylaromatic monomer and conjugated diene monomer; and thereafter (e) charging the reaction mixture with a coupling agent, wherein in each of steps (a) and (d) polymerization is conducted until essentially no free monomer is present.
Abstract:
A method for preparing tapered block copolymers which are particularly useful for blend components in blends with polymers of styrene. In the first embodiment of this invention the copolymers are prepared in a polymerization process by sequentially charging: (1) an initiator and monovinylaromatic monomers in the presence of a randomizer; (2) an initiator and monovinylaromatic monomers; (3) a mixture of monovinylaromatic and conjugated diene monomers; and (4) a coupling agent; to produce a polymodal tapered block copolymer. In a second embodiment of the invention tapered block copolymers are prepared in a polymerization process by sequentially charging: (1) an initiator and monovinylaromatic monomers in the presence of a randomizer; (2) an initiator and monovinylaromatic monomers; (3) a mixture of monovinylaromatic and conjugated diene monomers; (4) a mixture of monovinylaromatic and conjugated diene monomers; and (5) a coupling agent; to produce a polymodal tapered block copolymer. The invention copolymers and blends of the invention copolymers with polymers of styrene are particularly useful for applications such as packaging and food or drink containers which require transparency, low blueness, colorlessness, good impact strength and ductility.