Acrylic latex polymer

Hercules Res A. [Hercules] Resin dispersion tackifier for acrylic-latex polymers used in label, tape, and construction adhesives. 

The ever-increasing raw material choice available to the adhesive formulator is demonstrated with particular reference to Hercules resin dispersions for the modification of acrylic latex polymer systems used in pressure sensitive adhesive formulations. The requirements of a tackil g resin are examined and the advantages afforded by such products from Hercules as Tacolyn 1070, Tacolyn 3179 and Res A-2603 are discussed, in terms of their ability to offer balances of peel, tack and shear and consistently high levels of stability, it is claimed. 5 refs. 

CAM incorporation in the vinyl-acrylic latex polymers was verified using NMR spectroscopy (70). Polymer composition was determined by NMR analysis, and CAM incorporation was evidenced in both C and NMR spectra. The polymer composition indicates that CAM is incorporated in vinyl-acrylic latex polymers even more efficiently than butyl acrylate. NN data also indicate that some finite amount of the CAM isolated double bonds are retained throughout the emulsion polymerization, thereby allowing for post polymerization/auto-oxidative cure. 

The basic components of an acrylic latex polymer system are ... 

Synthetic emulsion polymers account for approximately 70% of the U.S. consumption of acrylate monomers. Major end uses for these latex polymers are coatings (32%), textiles (17%), adhesives (7%), paper (5%), and floor poHshes (3%). The U.S. producers of acryflc copolymer emulsions include Rohm and Haas, Reichhold, National Starch, Union Carbide, Air Products, Unocal, B. F. Goodrich, and H. B. Fuller. 

AH-acryHc (100%) latex emulsions are commonly recognized as the most durable paints for exterior use. Exterior grades are usuaHy copolymers of methyl methacrylate with butyl acrylate or 2-ethyIhexyl acrylate (see Acrylic ester polymers). Interior grades are based on methyl methacrylate copolymerized with butyl acrylate or ethyl acrylate. AcryHc latex emulsions are not commonly used in interior flat paints because these paints typicaHy do not require the kind of performance characteristics that acryHcs offer. However, for interior semigloss or gloss paints, aH-acryHc polymers and acryHc copolymers are used almost exclusively due to their exceUent gloss potential, adhesion characteristics, as weU as block and print resistance. 

This molecule is a copolymer with polymethyl methacrylate (PMMA) in acrylic latex paints, where the hydrophobic PMMA is surrounded by hydrophilic polyvinyl acetate molecules. Such a suspension of a hydrophobic polymer wrapped in a hydrophilic polymer is called a latex. 

Bonardi, C., Christou, Ph., Llauro-Darricades, M.E., Guillot, J., Guyot, A. and Pichot, C., 1989, Polymer Latex III International Conference, Characterization of Acrylic Latexes Functionalized by N-Methylol Acrylamide, 6/1-6/14, Plastics and Rubber Institute, London. 

Product Vinyl acetate, butyl acrylate, and vinyl neodecanoate (60/15.3/24.7[w/w]) latex polymer... 

One of the problems encountered in the entrapment of activated charcoal in a polymer matrix is the blinding-off of the pores of the charcoal, thus inactivating it. Because the pores of the carbon are responsible for its ability to adsorb organics, any pores that are filled or coated with a polymer matrix reduce its effectiveness. Conventional treatments involve blending the carbon into an acrylic latex and then applying the slurry to a reticulated foam. Upon drying, a coalescence encapsulates the carbon. 

Initiators -for acrylamide [ACRYLAMIDE POLYMERS] (Vol 1) -anionic initiators [INITIATORS - ANIONIC INITIATORS] (Voll4) -cationic initiators [INITIATORS - CATIONIC INITIATORS] (Vol 14) -in emulsion polymerization [LATEX TECHNOLOGY] (Vol 15) -for fluorocarbon elastomers [ELASTOMERS, SYNTHETIC - FLUOROCARBON ELASTOMERS] (Vol 8) -Free-radical initiators [INITIATORS - FREE-RADICAL INITIATORS] (Voll4) -organohthium compounds as [LITHIUM AND LITHIUM COMPOUNDS] (Vol 15) -peroxides as [PEROXIDES AND PEROXIDE COMPOUNDS - INORGANIC PEROXIDES] (Vol 18) -for propylene oxide [PROPYLENE OXIDE] (Vol 20) -for PUR polyols [POLYETHERS - PROPYLENE OXIDE POLYMERS] (Vol 19) -of suspension polymerization [ACRYLIC ESTER POLYMERS - SURVEY] (Vol 1)... 

Acrylics. There are two principal classes of acrylic sealants latex acrylics and solvent-release actylics. High molecular weight latex acrylic polymers are prepared by emulsion polymerization of alkyl esters of acrylic acid, The emulsion polymers are compounded inlo sealants by adding fillers, plasticizers, freeze-thaw stabilizers, thickeners, and adhesion promoters. As is true of the silicone lalex sealants, die acrylic latex sealants are easy to apply and clean with water. 

Composites can also be prepared by electropolymerization from solutions containing dissolved polymer 307). Since films of polypyrrole or polythiophene are normally porous, it seems most likely that the dissolved polymer is simply entrained in the pores. Similarly, composites have been prepared by polymerization of pyrrole in the presence of acrylic latex, giving blends with 10-30 % polypyrrole that are conducting yet processable 808). Presumably the polypyrrole is distributed throughout the latex particles. 

The second objective is to verify experimentally the predicted relationship between polymer polarity and surfactant adsorption by studying the adsorption of a non ionic surfactant that shows a saturation type isotherm behavior on vinyl acrylic latexes of varying polarity. 

In order to achieve the above objectives, three vinyl acrylic latexes of varying butyl acrylate content have been prepared and cleaned1 for use in the study. Several anionic and nonionic surfactants commonly usod in emulsion polymerization have been used to investigate the effects of surfactant structure and polymer composition on the solubilization process. Polarity of latex surface estimated from contact angle measurements have been used to study the effect of polymer polarity on surfactant adsorption. 

Figure 3. Thickening of vinyl acrylic latexes in the presence of NaLS ( 1) ((O) PVAC ho mo polymer (J ) 70/30 VA/BA copolymer)...

Latex thickening, a result of surfactant penetration and solubilization of the polymer, increases with the vinyl acetate content of vinyl acetate-butyl acrylate co-polymer latexes. 

Polarity of Vinyl Acrylic Latex and Surfactant Adsorption Contact angle measurements, dispersion and polar contribution to latex film surface tension and polarity of polymer calculated according to the method of Kaelble (10) of the three latex films are whown in Table V. It is seen that the polarity of the latex film decreases with increase in butyl acrylate content of the vinyl acrylic co-polymer. The polarity of the 70/30 (VA/BA) latex is very similar to that of the polybutyl acrylate homopolymer estimated to be about 0.21 (1). ... 

It is seen that the adsorption of Igepal CO-630 at the three latex/water interfaces decreases with increase in polarity of the vinyl acrylic latex surface. Explanation for such a decrease in surfactant adsorption at a polymer/water interface with increase in polymer polarity has been discussed in detail elsewhere (1). Briefly, increased polarity of the polymer lowers the interfacial free energy of the polymer latex/water interface and this, in turn, reduces the free energy of adsorption for a simple saturation type adsorption process of a surfactant at a latex surface in aqueous media. Such a lowering in free energy of surfactant adsorption at a polymer latex/water interface with increase in polymer polarity leads to the observed results, namely, decrease in the adsorption of Igepal CO-630 with polarity increase of the VA/BA latex particle. 

The polarity and adsorption data discussed above reveal some interesting aspects of the surface chemistry of vinyl acrylic latex surfaces. It is quite likely that the polarity of the latex films, expecially of the two co-polymers, determined by contact angle measurements may not correspond exactly with their respective latex surfaces in the dispersed state due to reorientation of polymer chains during film formation. But the surfactant adsorption data shows clearly that the three latex surfaces in their dispersed state do exhibit varying polarity paralleling the trend found from contact angle measurements. The result also shows that the surface of the co-polymer latex surface is a mixture of vinyl acetate and acrylate units. This result is somewhat unexpected in a vinyl acrylic latex, prepared by a batch... 

Figure 5. Effect of polymer polarity on the adsorption of Igepal CO-630 surfactant at vinyl acrylic latex/water interface ( 1)...

In agreement with our earlier studies (1,15), the adsorption results of Igepal CO-630 on the three vinyl acrylic latexes show that the area per molecule of surfactant can be related to the polarity of polymer surface. Further, the results show that one can employ the techniques discussed above to characterize the polarity of co-polymer latex surfaces. 

It is also shown that the adsorption of non-ionic surfactants at a vinyl acrylic latex/water interface that exhibit a saturation type isotherm can be related to the polarity of the polymer surface, in agreement with earlier sufactant adsorption studies. 

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