# US 5,703,171 A · Viscosity modifier polybutadiene polymers

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- Number: US 5,703,171 A
- Document ID: US5703171A
- Status: Granted
- Kind: A
- Application number: 08/487,360
- Filed: 1995-06-07
- Granted: 1997-12-30
- Earliest claimed: 1991-03-15
- Assignees: Exxon Chemical Patents Inc.
- Inventors: Mark Joseph Struglinski; Gary William VerStrate; Lewis J. Fetters
- Web page: https://patentgrep.com/patent/US5703171A

## CPC

- C10M 143/12: containing conjugated diene
- C08C 19/02: Hydrogenation
- C08F 8/04: Reduction, e.g. hydrogenation
- C08F 136/06: Butadiene
- C08F 297/02: using a catalyst of the anionic type
- C08F 297/048: {polymerising vinyl aromatic monomers, conjugated dienes and polar monomers}
- C08L 53/005: {Modified block copolymers}
- C10M 2205/06: containing conjugated dienes
- C10M: LUBRICATING COMPOSITIONS (well drilling compositions C09K8/02); USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION (mould release, i.e. separating, agents for metals B22C3/00, for plastics or substances in a plastic state, in general B29C33/56, for glass C03B40/02; textile lubricating compositions D06M11/00, D06M13/00, D06M15/00; immersion oils for microscopy G02B21/33)
- C08C: TREATMENT OR CHEMICAL MODIFICATION OF RUBBERS
- C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)

## Abstract

The present invention relates to hydrogenated polybutadiene comprising monomeric units of 1,4-butadiene and 1,2-butadiene addition products. The copolymer is hydrogenated and comprises at least 10% by weight of at least one crystallizable segment and at least one low crystallinity segment.

## Claims

### Claim 1

A process comprising the steps of:
forming through polymerization, a precursor polybutadiene block copolymer comprising at least one precursor crystallizable segment comprising 1,4-polybutadiene and at least one precursor low crystallinity segment of polybutadiene wherein butadiene is added to the polymer chain as 1,4 butadiene and 1,2 butadiene, the precursor block copolymer comprising at least 10 percent by weight precursor crystallizable segments, wherein polymerization comprises forming a segment comprising at least 70 mole percent butadiene added as 1,2-butadiene: forming a 1,4-polybutadiene segment; and forming a segment comprising at least 70 mole percent butadiene added as 1,2-butadiene;
adding a coupling agent to form a precursor star block copolymer; and
substantially hydrogenating the precursor polybutadiene star block copolymer to form a hydrogenated block copolymer, arms of which comprise at least 10 percent by weight of at least one crystallizable segment comprised of methylene units and having an average methylene content corresponding to a 1,4-polybutadiene content of at least about 20 mole percent, and at least one low crystallinity segment comprised of methylene units and substituted methylene units and having an average methylene content corresponding to a 1,4-polybutadiene content of less than about 20 mole percent.

### Claim 2 (depends on 1)

The process as recited in claim 1 wherein the star block copolymer has from 4 to 25 arms.

### Claim 3 (depends on 2)

The process as recited in claim 2 wherein the star block copolymer has from 5 to 15 arms.

### Claim 4 (depends on 1)

The process as recited in claim 1 wherein the star block copolymer has a weight average molecular weight of from 100,000 to 500,000.