STORAGE STABLE AQUEOUS ORGANIC PEROXIDE EMULSIONS

Abstract

Aqueous emulsion comprising: 25-70 wt % organic peroxide, based on the weight of the emulsion, a cyclohexane dicarboxylate ester, and water. This emulsion is storage stable and can be used for the production of polymers, in particular PVC, that come into contact with food products.

Claims

1. Aqueous emulsion comprising: 25-70 wt % organic peroxide, based on the weight of the emulsion, a cyclohexane dicarboxylate ester, and water.

2. Emulsion according to claim 1, wherein the cyclohexane dicarboxylate ester is di-isononyl cyclohexane dicarboxylate (DINCH).

3. Emulsion according to claim 1 wherein the cyclohexane dicarboxylate ester is present in an amount of 0.1-10 wt %, based on the weight of the emulsion.

4. Emulsion according to claim 1, additionally comprising an anti-freeze agent.

5. Emulsion according to claim 4, wherein the anti-freeze agent is selected from the group consisting of methanol, ethanol, isopropanol, (ethylene) glycol, propanediol, glycerol, and mixtures thereof.

6. Emulsion according to claim 1, additionally comprising a protective colloid.

7. Emulsion according to claim 1, additionally comprising an emulsifier.

8. Emulsion according to claim 7, wherein the emulsifier is a non-ionic surfactant.

9. A method of polymerizing a vinyl chloride monomer wherein the emulsion according to claim 1 is added to a vinyl chloride monomer in an effective amount.

Description

EXAMPLES

General Procedure

[0038] In the following Examples, the aqueous organic peroxide emulsions were made by the following general procedure: to a cooled vessel at 10 C. were added organic peroxide (final content is 50 wt %, based on the total weight of the emulsion), PVA (polyvinyl acetate, degree of hydrolysis 62.5-67.5%, ex Unitika), droplet growth inhibitor, plasticiser ester (see Tables), and non-ionic surfactant (C16/C18 ethoxylated alcohol), water, and methanol indicated in the Examples below. The organic peroxide was dispersed using an UltraTurrax type S25N-25GM (4 minutes/kg of emulsion) at full power, during which the temperature of the emulsion was kept below 15 C.

[0039] The droplet volume distribution was determined by means of a light scattering technique, using a Malvern type 3000 apparatus. In the Tables, d99 (expressed in m) is 99 percentile of the droplet volume distribution of the organic peroxide in the emulsion; d50 (expressed in m) is 50 percentile of the droplet volume distribution of the organic peroxide in the emulsion. The emulsion samples were stored at 20 C. and the data were collected at room temperature.

[0040] The viscosity was measured at 10 C. with a Brookfield LVT (spindle 3; at 12 and 30 RPM).

Example 1 and Comparative Examples A and B

[0041] Three emulsions were made according to the above procedure, using tert-butyl peroxyheptanoate as the peroxide and diisodecyl adipate (DIDA), dioctyl adipate (DOA), and di-isononyl cyclohexane dicarboxylate (DINCH) as the droplet growth inhibitor.

TABLE-US-00001 TABLE 1 Example A B 1 Peroxide (wt %) 50 50 50 PVA (wt %) 3.0 3.0 3.0 Surfactant (wt %) 0.5 0.5 0.5 DIDA (wt %) 0.9 DOA (wt %) 0.9 DINCH (wt %) 0.9 MeOH (wt %) 12.8 12.8 12.8 Water (wt %) 32.8 32.8 32.8 Droplet size: 1 day - d50/d99 0.5/1.1 1.4/3.3 0.5/1.3 2 weeks - d50/d99 1.5/4.0 3.7/9.5 1.9/4.1 4 weeks - d50/d99 5.8/15.0 2.2/5.9 8 weeks - d50/d99 2.4/5.4 3.4/8.3 12 weeks - d50/d99 2.9/6.8 3.9/9.6 Viscosity (mPa .Math. s): 1 day - 12/30 RPM 720/616 410/400 720/616 2 weeks - 12/30 RPM 360/332 290/280 310/292 4 weeks - 12/30 RPM 280/264 8 weeks - 12/30 RPM 350/340 290/280 12 weeks - 12/30 RPM 270/260 220/200

[0042] This Table shows that DINCH is a very good droplet growth inhibitor. Its performance is comparable to that of DIDA and much better than that of DOA. The latter resulted in a d99>15 m after 4 weeks.

[0043] In contrast to DIDA and DOA, DINCH is food contact approved.

Example 2 and Comparative Examples C and D

[0044] Example 1 and Comparative Examples A and B were repeated, except that tert-butyl peroxyneodecanoate was used as the peroxide.

TABLE-US-00002 TABLE 2 Example C D 2 Peroxide (wt %) 50 50 50 PVA (wt %) 2.8 2.8 2.8 Surfactant (wt %) 0.5 0.5 0.5 DIDA (wt %) 0.9 DOA (wt %) 0.9 DINCH (wt %) 0.9 MeOH (wt %) 12.7 12.7 12.7 Water (wt %) 33.1 33.1 33.1 Droplet size: 1 day - d50/d99 1.0/2.0 1.7/2.9 0.9/1.9 2 weeks - d50/d99 1.7/3.6 3.7/8.4 2.5/5.1 4 weeks - d50/d99 4.9/12.0 3.2/6.5 8 weeks - d50/d99 3.2/7.1 3.8/9.7 12 weeks - d50/d99 3.8/8.7 4.0/9.9 Viscosity (mPa .Math. s): 1 day - 12/30 RPM 560/516 460/440 550/496 2 weeks - 12/30 RPM 350/348 310/292 280/260 4 weeks - 12/30 RPM 290/284 8 weeks -12/30 RPM 390/356 240/323 12 weeks - 12/30 RPM 290/280 260/268

Example 3 and Comparative Examples E and F

[0045] Example 1 and Comparative Examples A and B were repeated, except that tert-amyl peroxyneodecanoate was used as the peroxide.

TABLE-US-00003 TABLE 3 Example E F 3 Peroxide (wt %) 50 50 50 PVA (wt %) 2.8 2.8 2.8 Surfactant (wt %) 0.5 0.5 0.5 DIDA (wt %) 0.9 DOA (wt %) 0.9 DINCH (wt %) 0.9 MeOH (wt %) 12.5 12.5 12.5 Water (wt %) 33.3 33.3 33.3 Droplet size: 1 day - d50/d99 1.3/2.5 1.8/3.4 1.0/1.8 2 weeks - d50/d99 2.4/4.5 4.2/9.7 2.6/5.2 4 weeks - d50/d99 6.1/12.4 3.5/7.3 8 weeks - d50/d99 3.5/7.8 4.0/10.3 12 weeks - d50/d99 3.9/10.0 4.9/12.0 Viscosity (mPa .Math. s): 1 day - 12/30 RPM 780/716 550/530 670/606 2 weeks - 12/30 RPM 510/496 390/368 370/356 4 weeks - 12/30 RPM 350/344 8 weeks - 12/30 RPM 430/412 420/366 12 weeks - 12/30 RPM 360/352 370/360