US2547396A - Stabilized paraffin wax - Google Patents

Description

Patented Apr. 3, 1951 clairRefinin-gGompany;NewzYork;

porati'on of'Maine N; Y., acor- N: Drawing. Application (Tctjober- L7, 1946 Serial No; 703,707

I Claim.

My invention concerns amethod for inhibiting the oxidation of paraffin waxand embraces, asa composition of matter, paraffin wax to which has been added the: anti-oxidant or stabilizer employed inthe practice of the method.

A Barafiin waxes; are in. extensive use by paper andcontainer, manufacturers as a: coating mate rial. inthe production of moisture-proof wrappers. and cartons for foodand related; industries. Before; application: of the wax to, the paper on pasteboard' surface, it is customary to heat it to a temperature of the order of 100 F.'-200 F., that, is to a. temperature 20 F.60 F. aboveitsmelting;

point, higher temperaturesbeing generally used in-the coating of cartons and the like than in the coating of paper.

. Unfortunately, parafiin wax, when heated to such temperatures, tends to oxidize, the, degree of oxidation depending upon the-lengthof time U it is maintained at the elevated temperature.- Some of the eifects of oxidation observable-inthe resolidified product are loss of hardness and tensile strength, discoloration, and offensive odor. All of these are obviously undesirable from the standpoint of employment of the wax as a paper or carton coating material; particularly where the paper or carton. is. to hev used, inthe packaging of. such items as food products, drugs, and cosmetics.

2: matbrialidentifiedin the trade as Dow Corning type- 200 fluid, This material is described in published Dow Corning literature as according with: the above" empirical formula and is available inanumber of viscosities, ranging from. 100- 1.000 centistokes (at 25 (3.). For my purpose I prefer the 100 centistoke material, butv the morev viscous grades may beapplicable in: some cases.

Aver-agemolecular weights for, the Dow- Corning;

200' series, are reported, in; the Journal of the- American. Chemical Society, vol. 2284490, 1946 The Dow Corningfiuids are generally described as, a: group of colorless, odorless, inert, mobile liquids which remain fluid at arctic temperatures. According to the literature, they have higher flash point than: petroleum oilsof equivalent viseosity;.'readily wet. clean, dry surfaces of glass, ceramics, and metals; are incompatible with and. freefromsolvent effect onxrubber, synthetic rub-' hers, andmrganic; plasticseven. at elevated temperatures; are insoluble in water and lower aliphatic alcohols; are soluble in most organic solvents; are stable to heat; are non-corrosive with respect to metals; are highly resistant to mineral acids"- and corrosive salt solutions; and have low dielectric,constantsandpower factorsover a wide frequency range. The physical properties of the 200.1type fluidsa are as follows:

Thefiima-lexpangim v t t k viscosity I Mm coe ,c1ent per lSCOSl y, centls 0 es at at 25 13., flash Sp. gr. at l'zbJgal. fig ggfg X101 cent po nt, 25 0. 22.1125 0. ,v e f smkes -25 to 25410 a I v 10000, 40 'F. 1009-1 210F 600 O. 968 8. 08 1. 4030 0; 926 0. 969 e 6. 0 82 32 200 615" 0.971 8, 10' 1.4031 0.921 0. 968' 1,300- 65 350 625 0. 972- 8. ll 1; 4032 0291 7 0. 966 1,959 260' 135 500 625' O} 972' 8. 11 l. 4033 0. 909 O. 965 3; 300- 370 1, 000 640 0.973 8. 12 1. 4035 0. 900 0. 963- 6, 500 735 260 In accordance with the presentinvention, I; inhibit the oxidation of paraffin wax and thereby retard or mitigate the development of the undesirable qualities indicated, by incorporating in the wax a small proportion of a liquid organesilicon. polymer conforming with the. empirical.

formula,

0113' one cm om-s io.- i-- (z st-012av em in Hi Using the 100 centist-oke material in. the practice of my invention, I have found that .01% onthe weight. of, the wax. isabout the minimum for satisfactory results. I have further found that, the use: of an, amount exceeding about; 114% on: the weight of the wax is not advisablebecause the tensile strength of the. wax may be thereby reduced;

The stabilizer is best incorporated in the wax with the wax-a in the liquid state. Generallyl In my experimental work I haveused 55 heat the wax to a temperature of about 10%" 68, pages above its melting point before mixing-in the stabilizer. After incorporation of the stabilizer, the

Tests before and after stabilizing F. without agitation or introduction of air or oxygen.

TABLE I parafiin waa:

with Dow Cormng flmd 200 [100 eentistokes] Unstabilized Wax .01% DC Unstabilized Wax Stabilized Wax after Unoxidized Wax Fluid after Oxidation Oxidation M. P., F 1341)-- 133.8" 131.8-.. 133.4. Color, Saybo1t. 30p 30p Darker than -16 25. Color, NPA Lighter than 1 Lighter than 1. Appearance White (Opaque) White (Opaque)- Lemon Yellow- White (Opaque). Oil Separation (Sweating None None Excess Slight. Tensile Strength. 21 290 Penetration at 77 F 16- 17 27 20. Penetration at 85 F 22 23 33- 28. Penetration at 90 F- 29. 28 53- 32. Penetration at 100 F 8 77 141 97. Cal. Oil, Per Oent .45. 47 4.0 1.72. Odor- None N n cid Little noticeable odor. Acid Number.. .02.... .O2 1.45.. .03. Saponfication Value .50 .50 3.8 .40.

heating may be continued until the wax has attained the proper temperature for a paper or carton coating operation or, depending upon circumstances, the source of heat may be withdrawn and the 'wax allowed to resolidify. Paper and container manufacturers operating on a large scale may elect to purchase unstabilized wax and to add the stabilizer as an incident of the heating of the wax to the processing temperature to avoid the necessity of twice melting the wax. It is best, however, for the producer of the wax to incorporate the stabilizer in order that the wax will be protected against surface oxidation during shipment and storage.

That the addition of efiective amounts of the stabilizer does not work a change of any significance in the characteristics of the wax is shown by the accompanying Table 1 giving the The determinations of Table II, submitted in further illustration of the improved resistance to oxidation of parafiin wax processed according to the invention, were made after an accelerated oxidation procedure in which air was introduced into the wax, maintained at a temperature of 892 F., at a rate of approximately .53 cubic foot per hour. In this procedure, the wax, 40 0a., is contained within a 10" x 1" Pyrex glass tube immersed in an agitated bath maintained at the stated temperature, the air being passed into the wax via a 5%" glass tube. Such vigorous conditions, of course, are never actually encountered in use of parafiin wax in paper coating and related Work, but such tests are nevertheless of great value in determining the effectiveness of materials proposed as anti-oxidants for parafiin waxes.

TABLE II Accelerated oxidation tests Acid Saponifi- Oxidmng Color Appearance of Solid 011 Sep- Calif. Time (Saybolt) Wax aration 3 @33 Oil Ulnitaihilized wax, 132I134 F., None- 0K +30.- White None 02 50 .45 None OK- 02 .50 1 hr- 0. 8 3. 00 75 1 hr 0. 7 2. 6 2 hr 1. 4 3. 5 1.10 2 hr. 1. 0 2. 5 0. 3 hr---" 1. 8 4. 1 1. 3 hr 1.2 3.2 0.79 '4 hr 2. 5 6. 2 2. 70 4 1 Light Lemon 2.0 4. 1 0.81 5 hr Light Yellow 3. 6 l0. 4. 3. 00 5 hr Very Light Yellow 2. 3 7.8 l. 00 6 hr Dark Yellow 4. O 12. 2 3. 20 6 hr Light Yellow 2. 8 9.1 1.10 7 hr Dark Ye1low 5.1 15. 3 3. 70 7 h Light Yellow. 3.1 11.4 1. 21 8 hr Very Dark Yellow. 6. 4 18.2 4. 00 3 b Light Yellow 4. 6 13. 2 1. 72.

1 Free oil present in small quantities. 2 Medium quantities. Large quantities.

characteristic of a representative wax before and after stabilization. Table 1 also shows, columns 70-additi0ns of the inhibitor.

3 and 4, the effect of oxidation on the stabilized, and unstabilized wax. The determinations in these columns were made after resolidification of samples which had been heated in a cc.

Table III illustrates the effect of progressive therefrom that the tensile strength of the wax decreases as the proportion of stabilizer is increased, also that the stabilizer has an efiect on the hardness of the wax as measured by its beaker, filled to capacity, for 8 hours at 375 75 penetrability.- H

It will be observed TABLE III Progressive add itions of inhibitor l32 134 F. Wax, Per Cent 99.99 99.93 99.93 99.94 99.92 99.90 99.30 99.00 99.40 99.20 99.00

Dow Corning Fluid 200, 100 Centistokes, Pei Cent .01 .02 .04 .00 .03 .10 .20 .40 .00 .90 1.00

Tests: 7, Melting Point, ASTM 133 3 133 133.4 133.4 133 4 133.4 133.4 133.4 133 4 133 2 133.2 Penetration at 77 F 17 17 17 17 17 17 17 1s 1s 1s Penetration at 35 13-. 23 25 20 20 20 20 27 23 23 2s Penetration at 90 I11. 23 29 29 30 34 34 35 35' 35 30 30 Penetration at 100 F- 77 7s 79 79 79 30 so 90 90 9s Tensile Strength 220 195 190 170 140 135 130 125 120 My invention, of course, is not limited to parafiin wax as employed in the production of FERENCES CITED moisture-proof Wrapping papers and contamers- The following references are of record in the I have described it with particular reference to 20 file of this p the paper industry because, at themoment, it is in that field that the invention app-ears to have UNITED STATES PATENTS the greatest commercial promise. Number Name Date I claim: 297,766 Chemin Apr. 29, 1884 A parafiin wax stabilized against oxidation by 9 2, 83,521 SOWa Aug. 28, 1945 the incorporation of from about .01 per cent to ,41 4 r u a 1947 .04 per cent of a liquid organo-silicon polymer t of the Dow Corning fluid 200 conforming with CLHER REFERENCES the empirical fo nula Rachow et al.. Journal of the American ChemiCal Society, 63, 798-800. CH3 30 Commercial Waxes, Bennett (1944) pages CHaSi 0- i 0- iCHa 10 1 and 53 H3 CH3 n a MILES A. JOANEN.