# US 5,703,203 A · Removal of oligomers from substantially crystalline, .alpha.-olefin polymers

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- Number: US 5,703,203 A
- Document ID: US5703203A
- Status: Granted
- Kind: A
- Application number: 08/414,870
- Filed: 1995-03-31
- Granted: 1997-12-30
- Earliest claimed: 1995-03-31
- Assignees: Montell North America Inc.
- Inventors: Richard J. Fezza; Stephen D. Williams
- Web page: https://patentgrep.com/patent/US5703203A

## CPC

- C08F 6/005: {from solid polymers}
- C10M 2205/028: containing aliphatic monomers having more than four carbon atoms
- C10M 2207/024: having at least two phenol groups but no condensed ring
- C10M 2207/026: with tertiary alkyl groups
- C10M 2207/027: Neutral salts thereof
- C10M 2207/125: having hydrocarbon chains of eight up to twenty-nine carbon atoms, i.e. fatty acids
- C10M 2207/129: having hydrocarbon chains of thirty or more carbon atoms
- C10M 2209/086: polycarboxylic, e.g. maleic acid
- C10M 2215/042: containing hydroxy groups; Alkoxylated derivatives thereof
- C10M 2215/064: Di- and triaryl amines
- C10M 2215/22: Heterocyclic nitrogen compounds
- C10M 2215/221: Six-membered rings containing nitrogen and carbon only
- C10M 2215/225: the rings containing both nitrogen and oxygen
- C10M 2215/226: Morpholines
- C10M 2215/30: Heterocyclic compounds
- C10M 2219/022: of hydrocarbons, e.g. olefines
- C10M 2219/024: of esters, e.g. fats
- C10M 2219/10: Heterocyclic compounds containing sulfur, selenium or tellurium compounds in the ring
- C10M 2219/102: containing sulfur and carbon only in the ring
- C10M 2219/104: containing sulfur and carbon with nitrogen or oxygen in the ring
- C10M 2219/106: Thiadiazoles
- C10M 2227/061: Esters derived from boron
- C10M 2229/02: Unspecified siloxanes; Silicones
- C10M 2229/05: containing atoms other than silicon, hydrogen, oxygen or carbon
- C10N 2040/08: Hydraulic fluids, e.g. brake-fluids
- C10N 2070/02: {Concentrating of additives}
- C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- 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)
- C10N: INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS

## Abstract

Disclosed is a method for removing oligomers from substantially crystalline, .alpha.-olefin polymer particles without having to melt the particles. The method comprises fluidizing a bed of the particles with a gas in which the oligomers are soluble, which bed is at a temperature at which the particles are not sticky, but at least lower molecular weight oligomers will evaporate therefrom, and maintaining the particles in the fluidized bed until a substantial portion of the oligomers have evaporated and have been removed from the bed by the fluidizing gas. By regulatng the bed temperature and the residence time of the particles in the bed the proportion and chain length of the oligomers removed can be controlled.

## Claims

### Claim 1

A method for stripping oligomers from finely divided, substantially crystalline, .alpha.-olefin polymer particles containing oligomers at a concentration of at least 250 parts by weight per million parts by weight of the polymer, which method comprises:
establishing a bed comprising said particles at a temperature sufficient to evaporate oligomers from said particles, but insufficient to cause said particles to become sticky to the extent they tend to substantially agglomerate and to adhere to walls and the like,
fluidizing said bed by passing through said bed at a bed fluidizing velocity a stream of gas inert to said particles and oligomers under prevailing conditions, whereby evaporated oligomers are removed from the bed, and
maintaining said particles at a temperature of 100.degree. to about 140.degree. C. for a period of about 1 hour to about 3 hours, sufficient for a substantial portion of said oligomers in said particles to evaporate therefrom,
the temperature and period of time being selected according to the proportion and maximum chain length of the oligomers to be stripped from the particles.

### Claim 2 (depends on 1)

A method according to claim 1 in which the steps are carried out by introducing into one zone of the bed said polymer particles having oligomers at said concentration of at least 250 parts by weight per million parts by weight of the polymer, and removing from another zone of the bed polymer particles with substantially reduced oligomers concentration.

### Claim 3 (depends on 1)

A method according to claim 1 in which said gas is nitrogen.

### Claim 4 (depends on 1)

A method according to claim 1 in which said polymer particles are semicrystalline propylene polymer particles.

### Claim 5 (depends on 1)

A method according to claim 1 in which the minimum chain length of the oligomers in the polymer particles to be treated by the method is nine carbon atoms.

### Claim 6 (depends on 5)

A method according to claim 5 in which the minimum chain length of the oligomers in the polymer particles after treatment by the method is about 18-36 carbon atoms.