Production of polymer emulsions

Details Production of polymer emulsions Production of polymer emulsions

1996-01-29

1998-09-08

Mulcahy, Peter D.

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

At least one aryl ring which is part of a fused or bridged...

524460, C08F 216

Patent

active

058046321

DESCRIPTION:

BRIEF SUMMARY
This application claims benefit of international application PCT/GB94/01692, filed Aug. 2, 1994.
The present invention relates to a process for the production of aqueous emulsions of certain polymer systems, to the aqueous emulsions so produced, and to their use in various applications.
The use of aqueous emulsions of polymers, commonly known as aqueous polymer latices, is well known in the art for numerous applications, and in particular for the provision of the binder material in coating applications.
It is known for some applications to be advantageous to employ an aqueous emulsion of a polymer system, containing a low molecular weight hydrophilic polymer and a hydrophobic emulsion polymer, that has been produced by a multistage process and in which (often) the hydrophilic polymer has been solubilised in the aqueous medium. Such latices may provide improvements in mechanical, physical or performance properties in comparison to conventional emulsion polymers.
U.S. Pat. No. 4894397, in particular, discloses the production of a latex in which a hydrophilic low-molecular weight polymer emulsion is formed in a first stage, and this is contacted with at least one hydrophobic, latex-forming monomer under polymerisation conditions to form a hydrophobic second-stage polymer, the pH of the resulting emulsion, said to be in the form of an inverse core-shell latex, being adjusted so as to dissolve the hydrophilic polymer, so creating a continuous aqueous phase of the hydrophilic polymer and discrete stabilized particles of the hydrophobic polymer.
In U.S. Pat. No. 4954558, on the other hand, a resin-fortified polymer emulsion is formed by emulsion-polymerising a monomer charge and adding to the polymerisation medium during the polymerisation a low-molecular weight support resin which is soluble or dispersible in water or alkali.
We have now discovered how to prepare aqueous emulsions of polymer systems comprising a low molecular weight acid-functional polymer and a hydrophobic polymer which have significant advantages in comparison to known emulsion polymer systems of this type.
According to the present invention there is provided a process for the production of an aqueous polymer emulsion which process comprises: groups using a free-radical polymerisation process which employs a free-radical initiator and, for the purpose of controlling molecular weight, a transition metal chelate complex, particularly a cobalt chelate complex, wherein said low molecular weight polymer has a number average molecular weight within the range of from 500 to 50,000; emulsion of a hydrophobic polymer from at least one olefinically unsaturated monomer, wherein the low molecular weight polymer of step a) is introduced to the aqueous medium of said emulsion polymerisation process before the start of and/or during said emulsion polymerisation process and becomes dissolved or dispersed in said aqueous medium.
In one embodiment of the invention, the low molecular weight acid-functional polymer becomes dissolved in the aqueous medium of the emulsion polymerisation of step b) and such dissolution in the aqueous medium may be effected or take place, subject of course to when it is added to the aqueous medium, prior to the start of the polymerisation of step b), during the polymerisation of step b), subsequent to the polymerisation of step b), or over two or more of these stages. Usually dissolution is effected prior to the start of polymerisation b) or during the polymerisation of b) or over both stages. Dissolution of the low molecular weight polymer is often achieved by neutralization of the acid groups, e.g. by raising the pH of the aqueous medium. Dispersion of the low molecular weight polymer in the aqueous medium may also be facilitated by neutralization of acid groups of the low molecular weight polymer.
There is also provided an aqueous polymer emulsion which is formable by a process as defined supra.
There is further provided the use of an aqueous polymer emulsion as defined supra in coating applications, and in particular in graphic a

REFERENCES:
patent: 4151143 (1979-04-01), Blank et al.
patent: 4414370 (1983-11-01), Hamielec et al.
patent: 4526945 (1985-07-01), Carlson et al.
patent: 4529787 (1985-07-01), Schmidt et al.
patent: 4546160 (1985-10-01), Brand et al.
patent: 4628071 (1986-12-01), Morgan
patent: 4680352 (1987-07-01), Janowicz et al.
patent: 4680354 (1987-07-01), Lin et al.
patent: 4722984 (1988-02-01), Janowicz
patent: 4746713 (1988-05-01), Janowicz et al.
patent: 4845149 (1989-07-01), Frazee
patent: 4876313 (1989-10-01), Lorah
patent: 4879333 (1989-11-01), Frazee
patent: 4886861 (1989-12-01), Janowicz
patent: 4894397 (1990-01-01), Morgan et al.
patent: 4904724 (1990-02-01), Auchter et al.
patent: 4954558 (1990-09-01), Tsaur
patent: 5010140 (1991-04-01), Antonelli et al.
patent: 5028677 (1991-07-01), Janowicz
patent: 5081166 (1992-01-01), Kiehlbauch et al.
patent: 5264530 (1993-11-01), Damon et al.
patent: 5306743 (1994-04-01), Klesse et al.
patent: 5362826 (1994-11-01), Berge et al.
patent: 5371151 (1994-12-01), Berge et al.
Enikolopyan et al, J. Polym. Sc. Polymer Chem. Ed., 19:879 (1981).
Cacioli et al, J. Macromol. Sci.-Chem., A23 (7), pp. 839-852 (1986).

Affiliated with

Also associated with

Rating

Production of polymer emulsions does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Production of polymer emulsions, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Production of polymer emulsions will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1282667