US5053436A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hollow acrylate polymer microspheres
Assignee: 3M Co
•
Filing: 1991-02-22
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Granted: 1991-10-01
•
Expires: 2011-02-22
Abstract
Abstract Hollow, polymeric, acrylate, infusible, inherently tacky, solvent-insoluble, solvent-dispersible, elastomeric pressure-sensitive adhesive microspheres having an average diameter of at least about 1 micrometer. Preferred microspheres are those wherein a majority of the hollow microspheres contain at least one of interior void having a diameter of at least 10% of the diameter of the microsphere. These hollow microspheres are useful as repositionable pressure-sensitive adhesives. The invention also provides pressure-sensitive adhesives consisting essentially of such hollow microspheres. Aqueous suspensions of these microspheres, processes for their preparation, spray repositionable pressure-sensitive adhesive compositions, and microsphere-coated sheet materials are also provided. Surprisingly, hollow microspheres of the invention show reduced or even eliminated adhesive transfer, in comparison with prior art repositionable pressure-sensitive adhesives which are based on solid microspheres.
Inventors
- 👤 Joaquin Delgado
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 13:04
CPC Classifications
C; C09; C09J; C09J133/00; C09J133/04; C09J133/06; C08; C08F; C08F2/00; C08F2/12; C08F2/16; C08F2/22; C08F2/24; C08L; C08L2205/00; C08L2205/14; C08L2205/18; C08L2205/20; C09J2301/00; C09J2301/30; C09J2301/302; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2982
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
108 words
A process for preparing an aqueous suspension of hollow, polymeric, acrylate, inherently tacky, infusible, solvent-insoluble, solvent-dispersible, elastomeric pressure-sensitive adhesive microspheres having a diameter of at least 1 micrometer, said process comprising the steps of: a) forming a water-in-oil emulsion of a water phase selected from the group consisting of water and aqueous solutions of at least one polar monomer in at least one oil phase monomer selected from the group consisting of alkyl acrylate and alkyl methacrylate esters; b) forming a water-in-oil-in-water emulsion by dispersing the water-in-oil emulsion into an aqueous phase containing an emulsifier having a hydrophilic-lipophilic balance value of at least 6; and c) initiating polymerization.
Claim 2
Dependent Claim
108 words
A process for preparing an aqueous suspension of hollow, polymeric, acrylate, inherently tacky, infusible, solvent-insoluble, solvent-dispersible, elastomeric pressure-sensitive adhesive microspheres having a diameter of at least 1 micrometer, said process comprising the steps of: a) forming a water-in-oil emulsion of a water phase selected from the group consisting of water and aqueous solutions of at least one polar monomer in at least one oil phase monomer selected from the group consisting of alkyl acrylate and alkyl methacrylate esters; b) forming a water-in-oil-in-water emulsion by dispersing the water-in-oil emulsion into an aqueous phase containing an emulsifier having a hydrophilic-lipophilic balance value of at least 6; and c) initiating polymerization.
Claim 3
Dependent Claim
24 words
A process according to claim 1 wherein the water-in-oil emulsion further comprises an emulsifier having a hydrophilic-lipophilic balance value of less than about 7.
Claim 4
Dependent Claim
16 words
A process according to claim 1 wherein polymerization is initiated by means of exposure to radiation.
Claim 5
Dependent Claim
16 words
A process according to claim 1 wherein polymerization is initiated by means of exposure to heat.
Claim 6
Dependent Claim
92 words
A process for preparing an aqueous suspension of hollow, polymeric, acrylate, inherently tacky, infusible, solvent-insoluble, solvent-dispersible, elastomeric pressure-sensitive adhesive microspheres having a diameter of at least 1 micrometer, said process comprising the steps of: a) forming droplets by mixing together i) at least one monomer selected from alkyl acrylate esters and alkyl methacrylate esters, ii) at least one moderately ionized polar monomer, and, iii) at least one emulsifier which is capable of producing a water-in-oil emulsion inside said droplets, said emulsion being substantially stable during emulsification and polymerization, and b) initiation polymerization.
Claim 7
Dependent Claim
92 words
A process for preparing an aqueous suspension of hollow, polymeric, acrylate, inherently tacky, infusible, solvent-insoluble, solvent-dispersible, elastomeric pressure-sensitive adhesive microspheres having a diameter of at least 1 micrometer, said process comprising the steps of: a) forming droplets by mixing together i) at least one monomer selected from alkyl acrylate esters and alkyl methacrylate esters, ii) at least one moderately ionized polar monomer, and, iii) at least one emulsifier which is capable of producing a water-in-oil emulsion inside said droplets, said emulsion being substantially stable during emulsification and polymerization, and b) initiation polymerization.
Claim 8
Dependent Claim
17 words
A process according to claim 5 wherein said emulsifier has an HLB value of at least 25.
Claim 9
Dependent Claim
16 words
A process according to claim 5 wherein polymerization is initiated by means of exposure to heat.
Claim 10
Dependent Claim
16 words
A process according to claim 4 wherein polymerization is initiated by means of exposure to heat.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-09-30 | 1995-04-01 | 1995-10-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-09-30 | 1999-04-01 | 1999-10-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-09-30 | 2003-04-01 | 2003-10-01 | $7700.00 | Window Closed / Lapsed |