US2506059A - Wax compositions - Google Patents

Description

Patented May 2, 1950 ICE WAX COMPOSITIONS John R. Bowman and William P. Ridenour, Pittsburgh, Pa., assigncrs to Gulf Research & Development Company, Pittsburgh, Pa, a corporation of Delaware No Drawing. Application June 7, 1946, Serial No. 675,318

Claims.

This invention relates to improved wax compositions and more particularly to paraffin wax compositions containing an additive to increase the tensile strength thereof.

Paraffin wax and paraffin wax products are used in many industries. In many of its applications and particularly in coating paper for such uses as wrapping, it is desirable to have as high a tensile strength as possible while at the same time retaining all of the desirable characteristics of a substantially pure parafiin wax. These other desirable characteristics include a high melting point, a uniform crystalline structure, and freedom from scuffing and mottling.

An object of the present invention is to provide paraifin wax compositions with increased tensile strength.

A further object of the invention is to provide an improved paraflin wax composition with increased tensile strength while at the same time retaining the other desirable features of paraffin wax.

These and other objects of this invention are achieved by a, composition comprising paraffin wax and from about 0.1 per cent to about 0.5 per cent by weight of a wax-soluble aluminum soap.

The method for obtaining the improved wax comprises thoroughly mixing paraffin wax in a molten state with the aluminum soap.

Of the aluminum soaps useful in the invention, aluminum stearate is preferable. Aluminum soaps of other fatty acids may be used so long as they are wax-soluble. These include the saturated fatty acid soaps in the range above C12.

The amount of the aluminum soap to be added may be varied, between about 0.1 per cent and about 0.5 per cent; 0.5 per cent is preferable. While amounts varying slightly from either of these limits may give some desirable results, amounts substantially larger than 0.5 per cent are undesirable. For example, at 0.75 per cent aluminum stearate in paraifin wax does not form a true solution, but by vigorous stirring a colloidal suspension may be obtained. Distinct plastic properties are evident and on brief standing a gel is formed which on re-stirring breaks up to give a distinctly non-homogeneous mixture.

The aluminum stearate used in the composition should be the di or tri-stearate, the monostearate showing no improvement as it is practically insoluble in the paraflin wax. The aluminum di or tri-stearate may be any of the products commercially available, but as will be seen from the test data below, that which is free of fatty acid is most desirable. It may be necessary to treat the commercial aluminum stearates by washing with a fatty acid solvent such as absolute ethyl alcohol, acetone,ethylacetate, etc. to remove the free acid.

The various types of parafiln wax may be improved according to the present invention, but the invention is particularly applicable to the grades of paraffin wax low in oil content. Improvement has been noted in a refined 122 F. ASTM melting point paraffin wax, but the highest tensile strength has been obtained with a highly refined parafiin wax having an ASTM melting point of 132 F.

The wax composition may contain other ingredients than paraffin and aluminum soaps but it will be understood that these ingredients should not be of a type or quantity that will substantially reduce the tensile strength, such as for example, oil.

The table below illustrates the tensile strength results obtained with a highly refined paraffin wax having an ASTM melting point of 132 F. The aluminum stearate used had the free fattyacid content indicated in the table and the acidfree samples were obtained by washing with ethyl alcohol.

TABLE Blends of aluminum stearate and pamfiin war (132 F. E. M. P.)

Lbs. improvement oi acid-free over commercial stearate Lbs. improvement of blend over straight wax Free Fatty content of soap, per cent Tensile strength F. Lbs. pull Per cent Added It will -be seen fromthe above"table'rthat' the commercial di-stearate is more effective'than the tri-stearate, but this is apparentl for the reason that the free acid content of the tri-stearate is substantially higher. acid, the tri-stearate becomes the more efiective additive.

The preferable compositiongis a'highly refined paraiiin wax containing about 0.5 per cent of Free fatty acids not only reduce the tensile strength of the waX, but tend to cause the wax to crumble, increase scuffing and causeinottling. These effects oppose the desirable ones induced -.by. aluminumsoaps;..therefore aluminum soaps as -low aspossiblein freejfatty .acid contents are deisirable. However, commercial aluminum soaps ..WhiQhcontain .free fatty acids in the, ordinary amounts .are .tolerable.

;,The.,-addition ofthe above specified amount of ,the. aluminum soap .tothe .parafiinwax increases the tensilestrengthand reducesmottling, asset .forth above. Inaddition, opacity is considerably increased as is also ductility. Paraffinwaxes containing-aluminum soaps will stand considerably greater stretchingand bending before breaking than. parafiin waxes without the aluminum soap. ..'-Ihev texture of thewax surface is. slightly altered, becomingnnctuous or soapy to. the touch and hav- Hing. less tendency toscuff under mild abrasion.

Asolid parafiin Wax composition'of increased tensile strength consisting. essentially of parafiin wax .and from about..0..1. per .cent to about 015 per acentrof; aluminum .stearate wherein. there, are. at least two stearate .radicals .per; aluminum atom 7 and saidaluminum stearate. issubstantiallyjfree rot-acid.-

-2., '.A...solid.- paraifin .wax composition .01" .inyer-eased tensilestrength consisting essentially .lo'f refined "paraffin wax :and about .025 .per .cent .of

On removal of itheifree :aluminum t'ri-stearatesubstantiallyiree of acid.

*3. A solid paraffin wax composition of increased tensile strength consisting essentially of refined stearate substantially free of acid.

4. -A'method forrmakinga composition consisting-essentially of-solid paraflin wax of increased tensilestrength comprising washing a commeraluminum tri-stearate substantially free of acid. n cial aluminum tri-stearate with ethyl alcohol unillil it is substantially acid-free and mixing it with rmoiten paraffln wax in proportion such that the wax contains from about 0.1 per cent to about 0.5 per center" said aluminum tri-stearate.

5. A method fol-making a composition consisting essentially of-solid paraffin wax of "increased "tensile strength'comprising washing a commercial aluminum-*stearate wherein thereare at least two ,stearate radicals for each aluminum atom with asolvent until it is substantially acid-free JOHN R. BOWMAN. WILLIAM P. RIDENOUR.

' REFERENCES CITED 7 The following, references are of record in the file ofthis patent:

UNITED STATES PATENTS Number "Name Date 2,130,560 "Plechner Sept. 20, 1938 2,32 O;"l4. Nill Junel, 1943 2,359,946 Sudholz et a1. Oct; 10, 1944 OTHER .REFERENCES 1 Metallic 'Soaps',published. by Metasap Chemical

Claims (1)

1. A SOLID PARAFFIN WAX COMPOSITION OF INCREASED TENSILE STRENGTH CONSISTING ESSENTIALLY OF PARAFFIN WAX AND FROM ABOUT 0.1 PER CENT TO ABOUT 0.5 PER CENT OF ALUMINUM STEARATE WHEREIN THERE ARE AT LEAST TWO STEARATE RADICALS PER ALUMINUM ATOM AND SAID ALUMINUM STEARATE IS SUBSTANTIALLY FREE OF ACID.