US4870143A
Expired / Lapsed
US
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Process for suspension polymerization
Assignee: Kanegafuchi Chemical Industry Co Ltd
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Filing: 1987-12-21
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Granted: 1989-09-26
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Expires: 2007-12-21
Abstract
Abstract By a process for suspension polymerization, which comprises steps of: supplying a slurry comprising droplets of a monomer liquid having a substantially uniform size dispersed in an aqueous dispersion medium to a tower type reactor in which said medium forms a downflow, and suspension polymerizing the monomer with avoiding merging or splitting of the droplets in a fluidized bed which is formed by the downflow of said medium and buoyancy of the monomer liquid droplets, wherein the specific gravity of said medium is made larger than that of a polymer particle to be produced by the addition of a water soluble inorganic salt to said medium, and a polycarboxylic acid type anionic polymeric surfactant is used as a suspension stabilizer for the monomer liquid droplets, polymer particles having a substantially uniform size are produced with high polymerization conversion.
Inventors
- 👤 Yoshiyuki Hashiguchi
- 👤 Masakiti Kishi
- 👤 Takehiko Yagyu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 01:51
CPC Classifications
B; B01; B01J; B01J19/00; B01J19/24; B01J19/2415; B01J19/2435; B01J8/00; B01J8/18; B01J8/20; C; C08; C08F; C08F2/00; C08F2/12; C08F2/16; C08F2/18; Y; Y10; Y10S; Y10S526/00; Y10S526/91
Claims Analysis
Total Claims: 39
Claim 1
Independent Claim
193 words
A process for suspension polymerization, which comprises steps of: supplying a slurry comprising droplets of a monomer liquid having a substantially uniform size dispersed in an aqueous dispersion medium to a tower reactor in which an aqueous dispersion medium heated at a polymerization temperature is charged from an upper portion of said reactor to form a downflow in the reactor, discharged from a lower part of said reactor and recycled to the upper portion of said reactor, and suspension polymerizing the monomer with avoiding merging or splitting of the droplets in a fluidized bed which is formed by the downflow of aqueous dispersion medium and buoyancy of the monomer liquid droplets, wherein the specific gravity of the aqueous dispersion medium is made larger than that of a polymer particle which is produced by suspension polymerization of the monomer liquid by the addition of a water soluble inorganic salt to the aqueous dispersion medium, and a polycarboxylic acid based anionic surfactant is used as a suspension stabilizer for the monomer liquid droplets, whereby a slurry comprising the aqueous dispersion medium and said polymer particles with high polymerization conversion is recovered directly from the reactor.
Claim 2
Dependent Claim
193 words
A process for suspension polymerization, which comprises steps of: supplying a slurry comprising droplets of a monomer liquid having a substantially uniform size dispersed in an aqueous dispersion medium to a tower reactor in which an aqueous dispersion medium heated at a polymerization temperature is charged from an upper portion of said reactor to form a downflow in the reactor, discharged from a lower part of said reactor and recycled to the upper portion of said reactor, and suspension polymerizing the monomer with avoiding merging or splitting of the droplets in a fluidized bed which is formed by the downflow of aqueous dispersion medium and buoyancy of the monomer liquid droplets, wherein the specific gravity of the aqueous dispersion medium is made larger than that of a polymer particle which is produced by suspension polymerization of the monomer liquid by the addition of a water soluble inorganic salt to the aqueous dispersion medium, and a polycarboxylic acid based anionic surfactant is used as a suspension stabilizer for the monomer liquid droplets, whereby a slurry comprising the aqueous dispersion medium and said polymer particles with high polymerization conversion is recovered directly from the reactor.
Claim 3
Dependent Claim
46 words
The process according to claim 1, wherein the specific gravity of the aqueous dispersion medium is adjusted by the addition of a water soluble inorganic salt to a range not less than 1.05 at room temperature according to the kind of the polymer to be produced.
Claim 4
Dependent Claim
33 words
The process according to claim 2, wherein the water soluble salt is at least one selected from the group consisting of chlorides, nitrides and sulfates of alkali metals, alkaline earth metals and ammonia.
Claim 5
Dependent Claim
39 words
The process according to claim 1, wherein the monomer liquid comprises at least one selected from the group consisting of mono-vinyl aromatic compounds, polyvinyl aromatic compounds, esters of α,β-ethylenically unsaturated carboxylic acids, unsaturated nitriles, aliphatic vinyl esters and halo-olefins.
Claim 6
Dependent Claim
13 words
The process according to claim 4, wherein the mono-vinyl aromatic compound is styrene.
Claim 7
Dependent Claim
17 words
The process according to claim 1, wherein the monomer liquid contains a polymerization initiator for radical polymerization.
Claim 8
Dependent Claim
17 words
The process according to claim 3, wherein the water soluble salt is a mixture of sodium chloride.
Claim 9
Dependent Claim
19 words
The process according to claim 7 wherein the water soluble salt mixture contains at least 95% of sodium chloride.
Claim 10
Dependent Claim
53 words
The process according to claim 7, wherein the maximum concentration of the mixture of sodium chloride in the aqueous dispersion medium is such concentration that the monomer liquid droplets are not merged by compression flattening due to a large difference of specific gravity between the monomer liquid droplets and the aqueous dispersion medium.
Claim 11
Dependent Claim
27 words
The process according to claim 9, wherein the concentration of the mixture of sodium chloride in the aqueous dispersion medium is from 7.5 to 15% by weight.
Claim 12
Dependent Claim
27 words
The process according to claim 9, wherein the concentration of the mixture of sodium chloride in the aqueous dispersion medium is from 12 to 13% by weight.
Claim 13
Dependent Claim
52 words
The process according to claim 1, wherein the suspension stabilizer comprising the polycarboxylic acid based anionic surfactant is used in combination with at least one suspension stabilizer selected from the group consisting of polymeric protective colloids, powdery inorganic compounds hardly soluble in water and anionic surfactants other than said polycarboxylic anionic surfactant.
Claim 14
Dependent Claim
31 words
The process according to claim 12, wherein the polymeric protective colloid is used in a concentration of from 30 to 10,000 ppm based on the weight of the aqueous dispersion medium.
Claim 15
Dependent Claim
13 words
The process according to claim 12, wherein the polymeric protective colloid is polyvinylalcohol.
Claim 16
Dependent Claim
15 words
The process according to claim 12, wherein the aqueous dispersion medium contains a polymerization inhibitor.
Claim 17
Dependent Claim
13 words
The process according to claim 15, wherein the polymerization inhibitor is sodium nitrite.
Claim 18
Dependent Claim
33 words
The process according to claim 12, wherein the powdery inorganic compound is used in a concentration of from 0.03 to 1 % by weight based on the weight of the aqueous dispersion medium.
Claim 19
Dependent Claim
15 words
The process according to claim 17, wherein the powdery inorganic compound is powdery calcium phosphate.
Claim 20
Dependent Claim
31 words
The process according to claim 12, wherein the concentration of the polycarboxylic acid based anionic surfactant is 0.0003 to 0.002% by weight based on the weight of the aqueous dispersion medium.
Claim 21
Dependent Claim
58 words
The process according to claim 1 wherein the polymer to be produced has such high polymerization conversion that the polymer particle can be resistant to shear force generated by agitation blades and/or mechanical force generated by a liquid conveying pump and also a centrifugal separator which is used for solid-liquid separation of the slurry containing the polymer particles.
Claim 22
Dependent Claim
17 words
The process according to claim 20, wherein the polymer has a polymerization conversion of at least 85%.
Claim 23
Dependent Claim
24 words
The process according to claim 1, wherein the downflow of the aqueous dispersion medium has a superficial velocity of from 0.1 to 1 cm/sec.
Claim 24
Dependent Claim
33 words
The process according to claim 1, wherein the flow rate of the aqueous dispersion medium in the lower portion of the reactor is smaller than that in the upper portion of the reactor.
Claim 25
Dependent Claim
33 words
The process according to claim 23, wherein the flow rate of the aqueous dispersion medium in the lower portion of the reactor is not larger than 0.3 cm/sec. in terms of superficial velocity.
Claim 26
Dependent Claim
28 words
The process according to claim 1, wherein the tower reactor comprises a multi-stage cylinder in which the lower portion has a larger inner diameter than the upper portion.
Claim 27
Dependent Claim
29 words
The process according to claim 1, wherein the tower type reactor has a conical shape having the smallest diameter at its top and the largest diameter at its bottom.
Claim 28
Dependent Claim
26 words
The process according to claim 1, wherein formation of air bubbles due to dissolved air is prevented in the monomer liquid and the aqueous dispersion medium.
Claim 29
Dependent Claim
28 words
The process according to claim 27, wherein the dissolved air is deaerated from the monomer liquid and the aqueous dispersion medium to prevent the formation of air bubbles.
Claim 30
Dependent Claim
27 words
The process according to claim 27, wherein the monomer liquid and the aqueous dispersion medium are pressurized in the reactor to prevent the formation of air bubbles.
Claim 31
Dependent Claim
41 words
The process according to claim 1, wherein a head tank for recovering air bubbles from the reactor head by raising them through the inlet for aqueous dispersion medium is installed at a position higher than any part of the circulating line.
Claim 32
Dependent Claim
34 words
The process according to claim 1, wherein the flow rates of the downflows in the circulating line connected to the inlet and in the reactor are smaller than a rising rate of air bubbles.
Claim 33
Dependent Claim
42 words
The process according to claim 1, wherein the monomer liquid droplets are formed in the aqueous dispersion medium supplied from the inlet for aqueous dispersion medium by passing the monomer liquid through an orifice of an orifice plate in a droplet-forming device.
Claim 34
Dependent Claim
29 words
The process according to claim 32, wherein the droplet size of the monomer liquid is made uniform by adjusting the viscosity of monomer liquid which passes through the orifice.
Claim 35
Dependent Claim
26 words
The process according to claim 33, wherein the viscosity of the monomer liquid is adjusted by dissolving a polymer of the monomer in the monomer liquid.
Claim 36
Dependent Claim
31 words
The process according to claim 32, wherein the monomer liquid droplets are formed with applying vibration to the orifice plate or to the monomer liquid on or near the orifice plate.
Claim 37
Dependent Claim
61 words
The process according to claim 1, wherein the polycarboxylic acid based anionic surfactant is at least one selected from the group consisting of a copolymer of a salt of maleic acid with a light metal selected from the group consisting of lithium, sodium, potassium, calcium, magnesium and aluminum and a salt of a copolymer of maleic acid with said light metal.
Claim 38
Dependent Claim
32 words
The process according to claim 36, wherein a comonomer is used which is compolymerizable with the salt of maleic acid or free maleic acid and is a C 4 -C 22 olefin.
Claim 39
Dependent Claim
38 words
The process according to claim 36, wherein a comonomer which is copolymerizable with a salt of maleic acid or free maleic acid is one selected from the group consisting of C 1 -C 8 alkyl methacrylate and styrene.
References Cited (Backward Citations)
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1992-09-25 | 1993-03-27 | 1993-09-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-09-25 | 1997-03-27 | 1997-09-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-09-25 | 2001-03-27 | 2001-09-26 | $7700.00 | Window Closed / Lapsed |