Claims
- 1. A process for producing a stable aqueous pressure sensitive adhesive polymer emulsion which comprises
- (a) preparing a substantially alkali insoluble, low molecular weight carboxylate-containing first stage polymer by aqueous emulsion polymerization under acidic conditions, the first stage emulsion polymer containing 30 to 55 equivalent % carboxylate monomers and having a Mn of <15,000 and a Tg<25.degree. C. as measured by Dynamic Mechanical Analysis,
- (b) conducting a second emulsion polymerization in the presence of the first stage polymer under acidic or basic conditions to produce a hydrophobic second stage polymer, the combination of monomers used in the first stage and second stage polymerizations resulting a two stage pressure sensitive adhesive emulsion polymer and
- (c) optionally, adjusting the pH of the resulting two stage pressure sensitive adhesive polymer emulsion to pH.gtoreq.4.
- 2. The process of claim 1 in which the second stage polymerization is conducted under acidic conditions.
- 3. The process of claim 1 in which the second stage polymerization is conducted under basic conditions.
- 4. The process of claim 1 in which the first stage polymer has a Mn of 5000 to 10,000.
- 5. The process of claim 1 in which the first stage polymer is prepared from monomers selected from the group consisting of esters of acrylic acid with C.sub.1 -C.sub.12 alcohols, esters of methacrylic acid with C.sub.1 -C.sub.12 alcohols, vinyl esters of C.sub.2 -C.sub.5 carboxylic acids, acrylonitrile, styrene, .alpha.-methylstyrene, and olefinically unsaturated C.sub.3 -C.sub.6 carboxylic monomers.
- 6. The process of claim 1 in which the second stage polymer is prepared from monomers selected from the group consisting of esters of acrylic acid with C.sub.1 -C.sub.12 alcohols, esters of methacrylic acid with C.sub.1 -C.sub.12 alcohols, esters of maleic acid with C.sub.1 -C.sub.12 alcohols, vinyl esters of C.sub.2 -C.sub.5 carboxylic acids, styrene, .alpha.-methylstyrene, acrylonitrile, C.sub.2 -C.sub.4 hydroxyalkyl acrylate, C.sub.2 -C.sub.4 hydroxyalkyl methacrylate, olefinically unsaturated C.sub.3 -C.sub.6 carboxylic monomers and sodium vinyl sulfonate.
- 7. The process of claim 1 in which the first stage polymer contains 35-50 equivalent % carboxylate monomers.
- 8. The process of claim 1 in which the first stage polymer comprises 5-25 wt % of the resultant emulsion polymer solids.
- 9. The process of claim 1 in which the first stage polymer comprises 8-15 wt % of the resultant emulsion polymer solids.
- 10. A process for producing a stable aqueous pressure sensitive adhesive polymer emulsion which comprises
- (a) preparing a substantially alkali insoluble carboxylate-containing first stage polymer having a Mn <15,000 by aqueous emulsion polymerization under acidic conditions, the first stage polymer consisting essentially of (i) monomers selected from the group consisting of esters of acrylic with C.sub.1 -C.sub.12 alcohols, esters of methacrylic acid with C.sub.1 -C.sub.12 alcohols, vinyl esters of C.sub.2 -C.sub.5 carboxylic acids, acrylonitrile, styrene, and .alpha.-methylstyrene, and (ii) 30 to 55 equivalent % olefinically unsaturated C.sub.3 -C.sub.6 carboxylic monomers and having a Tg.ltoreq.0.degree. C. (as measured by Dynamic Mechanical Analysis),
- (b) conducting a second emulsion polymerization in the presence of 5-25 wt % first stage polymer, based on resultant emulsion polymer solids, under acidic or basic conditions to produce a hydrophobic second stage polymer, the second stage polymer consisting essentially of monomers selected from the group consisting of esters of acrylic acid with C.sub.1 -C.sub.12 alcohols, esters of methacrylic acid with C.sub.1 -C.sub.12 alcohols, esters of maleic acid with C.sub.1 -C.sub.12 alcohols, vinyl esters of C.sub.2 -C.sub.5 carboxylic acids, styrene, .alpha.-methylstyrene, acrylonitrile, C.sub.2 -C.sub.4 hydroxyalkyl acrylate, C.sub.2 -C.sub.4 hydroxyalkyl methacrylate, olefinically unsaturated C.sub.3 -C.sub.6 carboxylic monomers and sodium vinyl sulfonate, the combination of monomers used in the first stage and second stage polymerizations resulting in a two stage pressure sensitive adhesive emulsion polymer and
- (c) optionally, adjusting the resulting two stage pressure sensitive adhesive polymer emulsion to pH>6.
- 11. The process of claim 10 in which the first stage polymer has a Mn of 5000 to 10,000.
- 12. The process of claim 10 in which the first stage polymer contains 35 to 50 equivalent % carboxylic monomers.
- 13. The process of claim 10 in which the first stage polymer comprises 8-15 wt % of the resultant emulsion polymer.
- 14. The process of claim 10 in which the resulting two stage polymer emulsion is adjusted to pH>7.
- 15. The process of claim 10 in which the second stage polymerization is conducted under acidic conditions.
- 16. A process for producing a stable aqueous pressure sensitive adhesive polymer emulsion which comprises
- (a) preparing a substantially alkali insoluble carboxylate-containing first stage polymer having a Mn.ltoreq.10,000 and a Tg.ltoreq.0.degree. C. (as measured by Dynamic Mechanical Analysis) by aqueous emulsion polymerization under acidic conditions, the first stage polymer consisting essentially of (i) monomers selected from the group consisting of esters of acrylic acid with C.sub.1 -C.sub.12 alcohols, esters of methacrylic acid with C.sub.1 -C.sub.12 alcohols, vinyl esters of C.sub.2 -C.sub.5 carboxylic acids, acrylonitrile, styrene, and .alpha.-methylstyrene, and (ii) 35-50 equivalent % olefinically unsaturated C.sub.3 -C.sub.6 carboxylic monomers,
- (b) conducting a second emulsion polymerization in the presence of 8-15 wt % first stage polymer, based on resultant emulsion polymer solids, under acidic or basic conditions to produce a hydrophobic second stage polymer, the second stage polymer consisting essentially of monomers selected from the group consisting of esters of acrylic acid with C.sub.1 -C.sub.12 alcohols, esters of methacrylic acid with C.sub.1 -C.sub.12 alcohols, esters of maleic acid with C.sub.1 -C.sub.12 alcohols, vinyl esters of C.sub.2 -C.sub.5 carboxylic acids, styrene, .alpha.-methylstyrene, acrylonitrile, C.sub.2 -C.sub.4 hydroxyalkyl acrylate, C.sub.2 -C.sub.4 hydroxyalkyl methacrylate, olefinically unsaturated C.sub.3 -C.sub.6 carboxylic monomers and sodium vinyl sulfonate, the combination of monomers used in the first stage and second stage polymerizations resulting in a two stage pressure sensitive adhesive emulsion polymer and
- (c) optionally, adjusting the resulting two stage pressure sensitive adhesive polymer emulsion to pH >7.
- 17. The process of claim 15 in which the first stage polymer consists essentially of vinyl acetate, 2-ethylhexyl acrylate, acrylic acid and methacrylic acid.
- 18. The process of claim 17 in which the second stage polymer consists essentially of monomers selected from the group consisting of sodium vinyl sulfonate, acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, butyl acrylate, 2-ethylhexyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate and styrene.
- 19. The process of claim 18 in which the second stage polymerization is conducted under acidic conditions.
- 20. The process of claim 1 which further comprises blending an aqueous tackifying resin dispersion into the aqueous adhesive polymer emulsion.
- 21. The process of claim 10 which further comprises blending an aqueous tackifying resin dispersion into the aqueous adhesive polymer emulsion.
- 22. The process of claim 16 which further comprises blending an aqueous tackifying resin dispersion into the aqueous adhesive polymer emulsion.
- 23. The process of claim 19 which further comprises blending an aqueous tackifying resin dispersion into the aqueous adhesive polymer emulsion.
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of U.S. application Ser. No. 08/059,845 filed 11 May 1993 now abandoned.
US Referenced Citations (8)
Foreign Referenced Citations (2)
Number |
Date |
Country |
814528 |
Jun 1969 |
CAX |
1107249 |
Mar 1968 |
GBX |
Non-Patent Literature Citations (1)
Entry |
Handbook of Adhesives, Third Edition, edited by Irving Skeist, von Nostrand, Reinhold, NY 1989 pp. 644-645. |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
59845 |
May 1993 |
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