US2429150A - Petroleum wax coating composition - Google Patents

Description

Patented Oct. 14, 1947 UNITED STATES PATENT FFICE PETROLEUM WAX COATING COMPOSITION ware No Drawing. Application November 14, 1944,

Serial No. 563,448

The present invention relates to surface coating and impregnating compositions, and more particularly to coating composition utilizing a petroleum wax as the major constituent and useful as a coating for wooden, paper, or fibre containers, the manufacture of laminated wrappers, and protection for metals and as a ship launching base coat.

In the building of ships, the keel is laid on dry land and as close to the water as is practicable. After the hull. is completed it is slid into the water; This is accomplished by means of ways which are constructed of heavy timber; The hull is supported on a carriage also constructed of wood which slides upon the ways. In order to. make it possible forthecarriage carrying the hull to slide down the, ways, the latter must be lubricated, and it is the usual practice to apply a solid fat or wax. termed the launching base coat to the wooden surface, and then apply grease or oil, known as the slip coat, over the solid fat or Wax.

A launching base coat should have high compression strength and hardness as compared to other solid or semi-solid lubricants since pressures ranging from to tons/sq. it. ar encountered when launching ships. The melting point of a base coat composition should be as high as possible, commensurate with its need for fluid application to, prevent liquefication due to exposure to summer sun or frictional heat generated by sliding of the ways on each other during ship launching. Such compositions should not be brittle when solidified and should show good adhesion to wood and other surfaces even on prolonged exposure to the washing action of sea water, for example, repeated submergence during hi h tides.

Wax base compositions are also useful in the water-proofing and protection of paper and other cellulosic cartons and shipping containers. In shipping many types of goods, e. g., ammunition, foods, readily corrodible instruments or parts, etc., the practice in the past, particularly in trans-ocean shipping, has been to use wooden boxes with metal linersybut with the growing scarcity of metal, shippers have been forced to 12 Claims- (01.106-219) resort to the use of laminated paper liners'or fibre board cartons. These types of shipping containers require protection from the elements, especially where they are to be shipped into tropical or semi-tropical. climates orwhere there is likelihood of, their being exposed to rain or moisture in. other forms such as immersion in .sea water during ship unloading operations. The

practice is to pack and seal the container and then dip it in a molten bath of the coating composition, thus eiiectively sealing the contents thereof from exterior influence. Coating compositions suitable for this type of use should have the following characteristics:

Melting point F., minimum Penetration, ASTM 25-35 Viscosity, Saybolt 40-55at 210 F. F'lash 375 F.,'minimum Complete liquefaction F., maximum Stability test- No sludge or separation in 48 hours at 210 F. Color Color shall not obscure stencil marking The composition-is generally applied in a molten state to the package by the use of mechanical equipment, permitting immersion at a temperature ranging between F. and 200 F. and the characteristics .of the compound should be such that neither excessive strike-through nor undesirably heavy coatings are obtained. The molten composition must also be completely homogeneous at the bath temperature to prevent rough and uneven films containing pin holes from being obtained. It is also essential that liberated air or moisture vaporized from the treated article quickly rise to the top of the liquid and escape as vapor to prevent bubble type pin holes. Consequently foam breakers such as silicones, etc., may be incorporated.

The principal object of the present invention is the production of a composition which, in conjunction with a suitable slip coat, will adequately lubricate ship launching ways. Another ohject of equal importance is the production of a composition which will afford protection to paper shipping cases and packages and will serve to moistureproof wrappings, wooden box linings, cartons, etc. Other and further objects will be apparent to those skilled in the art upon reading the following description.

It has been suggested in the art that metallic soaps such as aluminum, magnesium, barium and calcium soaps of fatty acids be employed to increase the melting point and hardness of waxy materials. However, these addition agents are not at all suited for our purpose because their bodying or gelatinizing effect and poor solubility render the molten product too viscous and nonuniform for successful application as a coating.

It has now been found that waxy compositions In addition to the hydrocarbon waxes and the lead soap in some cases it will be desirable to incorporate resinous materials for increased adhesivity. A suitable resin is a wood rosin polymer which has the following characteristics:

' F. Drop melting point 200-225 Acid number 140-160 Saponification number 150-170 Other ingredients such as stabilized or hydrogenated rosin, cumene or indene resins, fossil resins, animal and-vegetable waxes, fossil or ester waxes hydrocarbon polymer such as polybutene, styrene, etc., and the like may be employed in small proportions.

The lead soaps contemplated within the scope of the present invention are the lead soaps of saturated fatty acids of from 12 to 24 or more carbon atoms to the molecule. Typical examples of such acids are stearic acid, palmitic and hydrogenated lard, cottonseed, soya bean, corn, linseed, rape, mustard seed oil, and hydrogenated fish oil acids, which are saturated fatty acids predominantly of 16 and more carbon atoms. Lead soaps are usually prepared by direct saponification of the fatty acid with lead oxide (litharge) employing temperatures up to 325 F., although they can be prepared by double decomposition of alkali metal soaps with a lead salt such as the acetate. The quantity of lead oxide required to saponify the fatty acid is calculated from the following formula, using acid number and lead content values determined on representative samples of the materials within the reaction.

(Mg.KOH (gram)) Acid no. of fatty acid 0.l99 wt. in

tle, taking precaution that the temperature of the charge does not rise above 325 F. Vigorous agitation of the paddles is necessary to keep down foam and prevent the lead oxide from caking out on the bottom of the kettle. After all of the lead oxide has been added, the material is agitated at 300 F. for one hour to assure complete reaction. The product is filtered through a fine mesh screen to remove excess lead oxide. The lead soaps thus prepared are used in the compositions of the present invention within the range of from 1-8% by weight, preferably about 4%.

Although no special compounding procedure normally is required, the coating compositions are usually blended in the following manner: The waxy materials are placed in a steam jacketed kettle equipped with an agitator and heated to a temperature of from 225-250 F. After they have melted, the lead soap and other desired ingredients are added, and the mixture heated and stirred until complete solution is obtained. Any foaming that occurs may be controlled by the use of asuitable defoaming agent. The product is then withdrawn from the kettle and strained prior to packaging. If desired, dyes and antioxidants such as phenyl beta or alpha naphtyhlamine, guaiacol alkylated cresol, or the like may be added to the product just prior to its withdrawal from the kettle;

In evaluating launching base coats the usual melting point determinations may lead to erroneous conclusions as to the ability of the product to adhere to ways at elevated temperatures. High temperature adhesion is a most important consideration, particularly in warm climates where exposure to sunlight may result in the coating reaching temperatures in excess of 130 F., and therefore the following high temperature adhesion test has been developed.

A 2" x 4" piece of plywood is fitted with cardboard sides and the molten basecoat is poured in to a depth of On cooling, the cardboard is removed and the panel is placed in a dish at an angle of 30 from the horizontal. The dish' is then transferred to an oven where the temperature is maintained at 125 F. for 16 hours and then raised 5 F. for successive 16 hour periods. The proportion of material drawing or sliding into the dish from the wooden panel is noted after each 16 hour period. Any major loss of coating (i. e., greater than 50%) is recorded'as failure.

The adhesion of the coating to the launching ways is also of extreme importance, since tidal action will frequently tend to lift the base coat from the submerged portion of the way. A good indication of adhesivity can usually be obtained by attempting to pry the coating from a Wooden 'block. Where adhesivity is not as good as desired it frequently may be improved by incorporating a resin product in the composition.

' Still another desired property of launching base coats and more particularly of carton coatings lbs. fatty acid The fatty acid is charged a) a jacketed kettle equipped with a stirrer, preferably the straight No. lbs. lead oxide is a certain'degree of pliability of flexibility. This is usually measured relatively by coating 4" x 12" plywood strips with of material (applied molten) and measuring the degree to which the strip may be bent without fracturing the coating.

The fOHOWlng examples are given for the purpose of illustrating launching base coat compositions falling within the scope of the present invention and the nature of the improvement in characteristics obtained with the blending agents of the invention.

TABLE 1 Another use for which the compositions of the present invention are of considerable value is in the field'of temporary'protective coatings for. the prevention of corrosion of ferrous metal parts and Launching base coat compositions Penetration Maxi- M P (ASTM 13-5-25) mum y F. Compression Safe. No. Composition (ASTM Test at ggeg gn D1274") 77 F. 100 r. ature,

70% 132 M. P. Wax 1 1 Petrolatum 1 131 9 60 Border line 130 10% Hydrogenated Resins 65.75% 132 M. P. Wax--- 2 34.00%165 M. P Petroiat 138 10 Fail 130 0.25% Anti-oxidant 63.20% 132 M. P. Wax. 3 are tli sofit i fffii f ft 160 7 150 $353; Aggifixidant 1 ax 4 {80.00% 160 M P Deoiled Petroiatum. 156 8 17 19.2% 132 M ax 5 76.8% 160 M P Deoiled Petrolatum 171 6 13 d0 175 4.0% Lead Soap 8 1 Commercial product. 2 Phenyl alpha naphthylamine The following compositions, because of their hardness even at high atmospheric temperatures and their high melting point combined with a considerable degree of pliability, have'been found to be very satisfactory as fibre-board ammunition articles. It is the practice to protect many such items for storage or transport by dipping them in molten petrolatum to deposit a moistureexcluding film. The following data illustrate the improvement in moisture impermeability oband food carton coatings: tained with compositions of this invention.

Saybolt N M Maximum M. Pt., F Viscosity Cpmpiete Composition (ASTM at 210 'fggfi'fgi' Liquefaction D12730) ASTM Temperature,

67% 130 M. P. Wax 29% 160 M. P. Petrolatum- 142 45. 2 31 Below 150.

1 Lead soap of hydrogenated fish oil fatty acids.

From the foregoing formulas it will be noted that the percentage composition of our improved coating material may be varied within wide limits. Thus it may comprise as little as 10% to as much as of paraffin wax and from as little as 20% to as much as of petrolatum or preferably deoiled petrolatum or microcrystalline wax. In general the paraffin waX employed will have a melting point of about to 132 F. and as indicated in the tables above the petrolatum or deoiled petrolatum will have a melting point of about to F.

Humidity cabinet life testScmdblasted steel panels coated at 200 F.Tested at 100 F. and 100% humidity The compositions of this invention may on occasion also be modified by the addition of other materials such as dyes, defoamers, thickeners, polymers, inorganic fillers, solid alcohols, amides, amines, ketones, nitriles, mono or dibasic organic acid, fats and fatty oils, anti-oxidants, organic bases, rust preventive agents, metal naphthenates, sulfonates, solid halogenated waxes, coal tar resins, asphalts, and the like.

What is claimed is:

l. A coating composition comprising to 70% paraflin wax, 20 to 80% petrolatum, and from 1% to 8% of a lead soap of saturated fatty acids of 12-24 carbon atoms.

2. A coating composition comprising 1-0 to 70% parafi'in wax, 20 to 80% petrolatum, and 4% of a lead soap of saturated fatty acids of 12-24 carbon atoms.

3. A coating composition comprising 10 to 70% Daraffin wax, 20 to 80% microcrystalline wax, and from 1% to 8% of a lead soap of saturated fatty acids of 12-24 carbon atoms.

4. A coating composition comprising 10 to 70% paraffin wax, 20 to 80% petrolatum, 1% to 8% of lead soap of an acid having 12-24 carbon atoms to the molecule and 1% to 15% of hydrogenated rosin.

5. A coating composition comprising 10 to 70% parafiin wax, to 80% petrolatum, 4% of lead soap of an acid having 12-24 carbon atoms to the molecule and 1% to 15% of hydrogenated rosin.

6. A coating composition comprising 10 to 70% paraffin wax, 20 to 80% petrolatum, 4% lead soap of a saturated fatty acid having 12-24 carbon atoms to the molecule and 1% to 15% of hydrogenated rosin.

7. A coating composition comprising 10 to 70% paraifin wax, 20 to 80% petrolatum, 4% of lead soaps of hydrogenated fish oil acids, and 1% to 15% of hydrogenated rosin.

8. A coating composition comprising 10 to paraflin wax, 20-80% microcrystalline wax, 1 to 8% lead soap of hydrogenated fish oil acids, and 1-15% of a hydrogenated rosin.

9. A coating composition comprising 10 to 70% parafiin wax, 20 to petrolatum, 1 to 8% of lead soaps of saturated fatty acids of 12-24 carbon atoms and 10% hydrogenated rosin.

10. A coating composition consisting of 10 to 70% paraflin wax, 20 to 80% petrolatum, 4% lead soaps of hydrogenated fish oil acids and 10% hydrogenated rosin.

11. A coating composition comprising approximately 98% of a mixture consisting of 80 parts of micro-crystalline wax of approximately 160 F.

.melting point, and 20 parts of paraflin wax of approximately ASTM melting point, and 2% lead soap of saturated fatty acids having 12 to 24 carbon atoms to the molecule.

12. A coating composition as described in claim 11 wherein the lead soap is a lead soap of hydrogenated fish oil acids having 12 to 24 carbon atoms to the molecule.

JOHN C. ZIMMER. EJNAR. W. CARLSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS