TREATMENT PROCESS OF POLYMERIC DISPERSIONS BASED ON THE USE OF SPECIFIC ORGANIC PEROXIDES

Abstract

The present invention relates to a process for treating a polymeric dispersion prepared by polymerizing at least one or more unsaturated monomers comprising adding to said polymeric dispersion a sufficient amount of one or more organic peroxides selected from the group consisting of peroxydicarbonates, diacyl peroxides and mixtures thereof. The invention also deals with the use of organic peroxides selected from the group consisting of peroxydicarbonates, diacyl peroxides and mixtures thereof to treat a polymeric dispersion prepared by polymerizing at least one or more unsaturated monomers, preferably in order to reduce the amount of volatile organic compounds present in said polymeric dispersion.

Claims

1-13. (canceled)

14. A process for treating an aqueous polymer dispersion prepared by polymerizing at least one or more ethylenically unsaturated monomers, the process comprising adding to said polymeric dispersion one or more organic peroxides selected from the group consisting of peroxydicarbonates, diacyl peroxides and mixtures thereof.

15. The process according to claim 14, wherein the organic peroxides have a half-life temperature ranging from 40° C. to 75° C. at 10 hours.

16. The process according to claim 14, wherein the organic peroxides are diacyl peroxides selected from the group consisting of dilauroyl peroxide, disuccinic acid peroxide, dibenzoylperoxide, di-(3,3,5-trimethylhexanoyl)peroxide, didecanoyl peroxide and mixtures thereof.

17. The process according to claim 14, wherein the organic peroxides are peroxydicarbonates selected from the group consisting of diisopropyl peroxydicarbonate, di(2-ethylhexyl)peroxydicarbonate, di(s ec-butyl) peroxydicarbonate, di(n-propyl) peroxydicarbonate, bis(tert-butylcyclohexyl)peroxydicarbonate, di(3-methoxybutyl)peroxydicarbonate, dicetylperoxidicarbonate, dimyristylperoxydicarbonate, bis (4-tert)butylcyclohexyl) peroxydicarbonate and mixtures thereof.

18. The process according to claim 14, wherein the organic peroxide(s) are added to the polymeric dispersion in an amount ranging from 0.2% to 5% by weight, relative to the total weight of the polymeric dispersion.

19. The process according to claim 14, wherein the unsaturated monomers are selected from the group consisting of vinyl monomers, styrene or alkyl-substituted styrenes; butadiene; vinyl acetate, vinyl propionate, or other vinyl esters; vinyl chloride, vinylidene chloride, and N-vinyl pyrollidone; allyl methacrylate, diallyl phthalate, 1,3-butylene glycol dimethacrylate, 1,6- hexanedioldiacrylate, and divinyl benzene; (meth)acrylic acid, crotonic acid, itaconic acid, sulfoethyl methacrylate, phosphoethyl methacrylate, fumaric acid, maleic acid, monomethyl itaconate, monomethyl fumarate, monobutyl fumarate, maleic anhydride; and mixtures thereof.

20. The process according to claim 14, wherein the polymeric dispersion further comprises one or more residual monomers issued from the polymerization of the unsaturated monomers.

21. The process according to claim 14, wherein said treatment is a post-polymerization step of a process of polymerization of at least one or more unsaturated monomers.

22. The process according to claim 14, wherein the polymeric dispersion is an aqueous dispersion of (meth)acrylic polymer.

23. The process according to claim 14, wherein adding the one or more organic peroxides to the aqueous polymeric dispersion reduces an amount of volatile organic compounds present in said aqueous polymeric dispersion.

24. The process according to claim 14, wherein adding the one or more organic peroxides to the aqueous polymeric dispersion improves an odor of said polymeric dispersion.

25. A polymeric dispersion, obtainable from the process as defined in claim 14.

26. The process of claim 19, wherein vinyl monomers are selected from the group consisting of monoethylenically-unsaturated (meth)acrylic monomers.

27. The process of claim 26, wherein the monoethylenically-unsaturated (meth)acrylic monomers are selected from the group consisting of esters, amides, and nitriles of (meth)acrylic acid.

28. The process of claim 27, wherein the monoethylenically-unsaturated (meth)acrylic monomers are selected from the group consisting of methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, decyl acrylate, lauryl acrylate, stearyl acrylate, methyl methacrylate, butyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, aminoalkyl (meth)acrylate, N-alkyl aminoalkyl (methacrylate), N,N-dialkyl aminoalkyl (meth)acrylate; (meth)acrylonitrile and (meth)acrylamide.

Description

EXAMPLES

[0097] I. Preparation of the Polymeric Dispersion

[0098] The features of an aqueous acrylic resin (ENCOR® 5181 CS, produced by ACR, CHINA) are given in Table 1 detailed below.

TABLE-US-00001 TABLE 1 Features the acrylic resin Solid content % Viscosity, cps 55~57 800

[0099] Butyl acrylate (denoted hereafter BA) is added to the aqueous acrylic resin detailed in Table 1 in order to obtain an overall amount of 2000 ppm. The mixture is then stirred and dispersed for 1 hour and half to obtain an aqueous acrylic dispersion.

[0100] II. Tested Organic Peroxides

[0101] The organic peroxides implemented in the experimental protocol described hereafter are listed below: [0102] t-Butyl peroxyneodecanoate sold under the name Luperox® 10M75 (denoted 10M75) having a half-life temperature at 10 hours of 48° C., [0103] tert-amyl peroxypivalate sold under the name Luperox® 554M75 (denoted 554M75) having a half-life temperature at 10 hours of 55° C., [0104] tert-butyl hydroperoxide and sodium pyrosulfite (denoted TBHP from Arkema+SBS from Enox) [0105] bis(tert-butylcyclohexyl) peroxydicarbonate having a half-life temperature at 10 hours of 48° C., [0106] di(2-ethylhexyl)peroxydicarbonate sold under the name of Luperox® 223M75 (denoted 223M75) having a half-life temperature at 10 hours of 49° C. [0107] dibenzoyl peroxide sold under the name of Luperox® A75 (denoted A75) having a half-life temperature at 10 hours of 73° C., [0108] dilauroyl peroxide sold under the name of Luperox® LP (denoted LP) having a half-life temperature at 10 hours of 64° C.

[0109] III. Experimental Protocol

[0110] 2.4 grams of dilauroyl peroxide sold under the name Luperox® LP by Arkema are added to the 150 grams of aqueous acrylic dispersion previously described by one shot at a temperature of 80° C. After 3 hours, the residual concentration of volatile organic compounds in the dispersion is recorded.

[0111] This protocol is identical for all the organic peroxides described in part II except for the redox system tert-butyl hydroperoxide and sodium pyrosulfite (TBHP+SBS) wherein tert-butyl hydroperoxide has been added at 60° C. for 3 hours.

[0112] IV. Results

[0113] The results are given in Table 2 below:

TABLE-US-00002 TABLE 2 Assessment of the volatile organic compounds present in the aqueous acrylic dispersion Tert-amyl Tert-buty alcohol Residual Acetone, alcohol(TBA) (TAA), Benzene, Ingredients BA, ppm ppm ppm ppm ppm TBHP + SBS 28 271 268 / / 554M75 1112 96 / 49 / 10M75 532 39 1471  / / A75 18 / / / 324 LP 22 / / / / bis(tert- 36 / / / / butylcyclohexyl) peroxydicarbonate 223M75 88 / / / /

[0114] The results show that the redox system TBHP+SBS generates a significant amount of new volatile organic compounds whereas the organic peroxides used according to the present invention LP, 223M75 and bis(tert-butylcyclohexyl) peroxydicarbonate are able to significantly reduce the amount of residual butyl acrylate (BA) without generating new additional components.

[0115] The results also show that the peroxyesters 554M75 and 10M75 are less efficient than the organic peroxides the present invention in terms of reducing the amount of residual butyl acrylate.

[0116] In addition, the tested peroxyesters also generate new additional volatile organic compounds, such as acetone tert-amylalcohol and tert-butylalcohol, i.e. both non-polymerizable and polymerizable volatile organic compounds.

[0117] Finally, the results also demonstrate that Luperox® A75 (dibenzoylperoxide) which has a half-life temperature at 10 hours of 73° C. is able to reduce the residual amount of butyl acrylate.