US4722943A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Composition and process for drying and expanding microspheres
Assignee: Henkel Corp
•
Filing: 1987-03-19
•
Granted: 1988-02-02
•
Expires: 2007-03-19
Abstract
Abstract Microsphere wet cake is mixed with a processing aid effective to prevent agglomeration and surface bonding of the microspheres, and thereafter removing water by drying with continuous mixing, optionally also under reduced pressure, i.e. vacuum drying. By the control of the application of heat and balancing temperature and the mixing, and optionally also the reduced pressure, it is possible to also control expansion of the microspheres from substantially none to substantially theoretical limits of expansion. The processing aid in the present invention is any one of a wide diversity of materials which meet the requirements of the intended function, i.e., to prevent the agglomeration of the microspheres during the process. Suitable materials include, by way of example, dry inorganic pigments or filler materials, and the like, and related organic materials.
Inventors
- 👤 George E. Melber
- 👤 William A. Oswald
- 👤 Leon E. Wolinski
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 16:23
CPC Classifications
B; B82; B82Y; B82Y30/00; B01; B01J; B01J13/00; B01J13/02; B01J13/20; B01J13/206; C; C08; C08J; C08J3/00; C08J3/12; C08J3/124; C08J9/00; C08J9/32; C01; C01P; C01P2004/00; C01P2004/30; C01P2004/32; C01P2004/34; C01P2004/60; C01P2004/61; C01P2004/62; C01P2004/64; C01P2004/80; C01P2006/00; C01P2006/10; C01P2006/20; C01P2006/32; C01P2006/33; C01P2006/34; C01P2006/60; C01P2006/80; C01P2006/82; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2982; Y10T428/2991; Y10T428/2998
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
106 words
The method of drying expandable thermoplastic polymer microspheres in a wet cake to produce free-flowing dry microspheres comprising the steps of: A. mixing a thermoplastic microsphere wet cake with a processing aid, wherein said processing aid is a free-flowing particulate or fibrous solid, having a softening or melting or point at a temperature above that of said thermoplastic, B. drying said wet cake with continuous mixing at a temperature and for a time sufficient to remove sufficient water to produce a free flowing particulate microspheres having a coating of said processing aid embedded in and/or adhered to the surfaces thereof, and C. Collecting free-flowing dry microspheres.
Claim 2
Independent Claim
106 words
The method of drying expandable thermoplastic polymer microspheres in a wet cake to produce free-flowing dry microspheres comprising the steps of: A. mixing a thermoplastic microsphere wet cake with a processing aid, wherein said processing aid is a free-flowing particulate or fibrous solid, having a softening or melting or point at a temperature above that of said thermoplastic, B. drying said wet cake with continuous mixing at a temperature and for a time sufficient to remove sufficient water to produce a free flowing particulate microspheres having a coating of said processing aid embedded in and/or adhered to the surfaces thereof, and C. Collecting free-flowing dry microspheres.
Claim 3
Dependent Claim
22 words
The method of claim 1 wherein said drying step is at a temperature and for a time sufficient to expand said microspheres.
Claim 4
Dependent Claim
26 words
The method of claim 1 wherein said drying step is at a temperature and for a time such that substantially no expansion of the microspheres occurs.
Claim 5
Dependent Claim
16 words
The method of claim 1 wherein said drying step is at a reduced pressure below ambient.
Claim 6
Dependent Claim
25 words
The method of claim 1 wherein said drying step is at a pressure in the range of from ambient to about 1 mm Hg absolute.
Claim 7
Dependent Claim
26 words
The method of claim 1 wherein said drying step is sufficient to remove water to a level not more than one weight percent of the microspheres.
Claim 8
Dependent Claim
13 words
The method of claim 1 wherein said drying step is at ambient pressure.
Claim 9
Dependent Claim
50 words
The process of claim 1 wherein said processing aid is a member selected from the group consisting of talc, calcium carbonate, barium sulfate, alumina, silica, titanium dioxide, zinc oxide, spherical beads, or hollow beads, of ceramics, quartz, or glass, glass fibers, cotton flock, carbon and graphite fibers, and mixtures thereof.
Claim 10
Dependent Claim
35 words
The process of claim 1 wherein said dry, free-flowing microspheres comprise from about 3 to about 80 weight percent hollow thermoplastic microspheres and from about 97 to about 20 weight percent of a processing aid.
References Cited (Backward Citations)
US4397799A
Cited
US4513106A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-02-01 | 1991-08-03 | 1992-02-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-02-01 | 1995-08-03 | 1996-02-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-02-01 | 1999-08-03 | 2000-02-02 | $7700.00 | Window Closed / Lapsed |