US2320645A - Wax composition - Google Patents

Description

Patented June 1, 1943 UNITED STATES PATENT OFFICE WAX COMPOSITION Edward A. Nill, Detroit, Mich., assignor to The H. A. Montgomery Company, Detroit, Mich, a

corporation of Michigan No Drawing. Application September 14, 1938,

Serial No. 229,917

11 Claims.

This invention relates to improved wax compositions.

Wax products are used in many industries, and it is frequently desirable to provide a wax product with improved properties. The Liebrich Patent No. 741,584, granted October 13, 1903, discloses the use of fatty acid anilides such as stearanilid for raising the melting point of parafiin wax, petrolateum and the like. According to the present invention it is not only possible to materially raise the melting point of many different kinds of waxes, including parafiin,'ceresin, ozokerite, montan wax and the like, but also toprovide wax compositions having improved physical An object of the present invention is to pro-' vide wax compositions with improved physical properties, such as high melting 'point, increased ductility and high tensile strength, fine grain structures and improved moisture repellent characteristics.

A further object is to provide improved wax compositions which are stable, retaining their-1m: proved physical properties over long periods of time, so that oxidation thereof substantially is prevented and the giving oif of objectionable odors is eliminated.

A still further object is to provide wax compositions having melting points such that they may be made sterile and valuable for use in the food container industry.

Another object of the present invention is to provide improved wax compositions of the type mentioned which may be made readily and inexpensively.

Another object is to provide a composition which may be used in various proportions in connection with various hydrocarbon waxe to improve their physical properties, and which may also be used as an additive to other waxes or a substitute therefor in many applications.

Another objectis to provide stable wax emulsions and a method of making the same.

According to the present invention, improved wax compositions may be made by the addition of one or more ingredients to raise substantially the melting point of the wax composition and one or more ingredients to increase the ductility and tensile strength and to improve the moisturerepellent characteristics.

Various ingredients may be used to raise the melting point. It has been found that fatty substances containing glycerides are more efiective to raise the melting point of waxes than compounds heretofore known. Of the substances containing glycerides the most effective are those having a relatively high Titer test, that is above 46 C. or so. It is usually true that substances having higher Titer tests cause larger increases in the melting points of waxes. Glycerides having Titer tests within the range of from about 46 C.

to as high as about 70 C. or higher appear to be preferable. Since hydrogenation may produce an increase in the Titer tests of unsaturated fatty substances, hydrogenated glycerides are very desirable ingredients to incorporate in wax compositions to raise the melting points thereof.

Examples of compounds having the property of greatly increasing the melting point of the mineral waxes are pure fatty acid glycerides; hy-' drogenated natural fats and oils, such as fish oil,

soya bean oil, cottonseed oil, castor oil and animal fats; and natural glycerides, such as cottonseed stearine, beef stearine, etc. Generally the natural glycerides are more saturated, and for this reason it is not necessary to hydrogenate them.

since hydrogenation would not have a great deal of eifect on the physical properties thereof. The

above fatty substances may be used alone or it may be desirable to combine two or more of them for use as ingredients in wax compositions.

Derivatives of fatty acids including stearic,'palmitic, etc. have the eifect of increasing tensile "strength, ductility, water repellent characteristics, etc. as well as tending to further raise the melting point, and may be used to advantage in conjunction with one or more of the above ingredients which materially-raise the melting point of waxes. Heavy metal soaps of fatty acids have a pronounced eiiect on ductility, tensile strength, etc. Such heavy metal soaps, as calcium, magnesium and aluminum soaps, are insoluble and have the property not only of increasing tensile strength and ductility, and causing refinement of the grain, but also have the property of increasing the melting point of the wax compomay be used to improve the physical characteristics of waxes.

Addition of a hydrogenated glyceride and a heavy metal soap to unrefined scale wax considerably raises the melting point of the resultant wax composition. However, it was found that other properties were favorably affected to a marked extent, depending on the amount of ing'redients' added. For example, the toughness, tensile strength and ductility of the wax compositions were appreciably increased over commercial wax compositions. This is believed to be due to the fact that the addition of the above substances gives an appreciable grain refinement to the wax or waxes so that the crystals are relatively finer and of more uniform size. It seems that the grain refinement materially aids in improving the water repelling qualities of the wax or waxes, and, consequently, renders them very desirable for use in waterproofing products, such. products being impregnated with or having applied thereto a coating of these improved wax compositions. I

The amount of ingredients added depends largely upon the properties, and particularly the melting point, desired in the wax composition, and it has been found when the per cent of admixture is plotted against melting point temperature the curve goes up rapidly to somewhere around the region of about 5 to '7.5%'

admixture, varying somewhat with the specific ingredients used. From this point on the ad- ,mixture does not create large changes in the melting' point, and in some cases may even create a decrease in the melting point.- How ever, it may be desirable to produce compositions in which the admixture is made in amounts of 7.5% or even considerably higher to obtain compositions having greatly increased hardness,

for example.

In order to provide a composition which may be conveniently handled and shipped for addition, at the refinery, to waxes, such as slack wax, scale wax or refined wax, it has been found desirable to make up a mixture of the desired ingredients to provide an additive composition which will not only increase the melting point of the wax but will render the waxtough, duetile and give it an increased tensile strength, as well as improve its water-repellent properties. To provide such additive compositions or bases for improving wax, it is desirable to use ingredients which effect a substantial increase in the melting point of the wax, and ingredients which give the properties of toughness, ductility and waterproofing.

In making such an additive composition or base for improvement of waxes, a particularly desirable constituent to effect a pronounced increase in the melting point of waxes is a hydrogenated mixture of vegetable oils having a Titer test of about 60-65 C. Another desirable ingredient to use in the additive composition, or base is hydrogenated castor oil which may be made to have a Titer test of about 69 C.

On account of their effect in increasing tensile strength and improving the grain structure, one or more heavy metalsoaps may be a constituent of the additive base.

The heavy metal fatty acid soaps, such as magnesium, calcium and aluminum soaps of stearic acid, are practically insoluble in water. However, such soaps are somewhat soluble in composition. Thissolubility is greatly increased by the use of a free fatty acid, such as stearic acid. As previously mentioned, such soaps have the property of increasing the ductility and decreasing the grain size of the wax, as well as tending to increase the melting point of the composition.

Usually such insoluble soaps are soluble at elevated temperatures in an additive composition which contains glycerides and the like. In the presence of a free fatty acid, however, the insoluble soaps may be incorporated as an ingredient in the additive base or the wax composi'- tion at a much lower temperature.

Calcium stearate, for example, is an excellent ingredient for the wax compositions, in that it is very efiective in raising the melting point of the wax, as well as 'having the property of materially improving the'tensile strength, ductility and water-repellent characteristics of the wax composition. However, when calicum stearate is added to the additive base, or wax composition including glycerides and the like, it requires a temperature as high as, or higher than, 300 F. in order to combine therewith.

If a free fatty acid, such as stearic acid, is present, calcium stearate may be combined with the additive composition or with thewax composition at a much lower temperature. In making the mixture, one part of stearic acid may be utilized with ten parts of calcium soap and combinationwill take place at a temperature of 250 F. or lower. Lesser amounts, however, than the proportion of 1:10 will effect a decrease in the temperature required. A considerably less amount of free fatty acid, such as .5% or less,

is necessary to cause low temperature combina-' characteristic of raising the viscosity when the wax composition is heated to a. temperature as high or higher than its melting point. Thus. it may be seen that a wax composition having added thereto an admixture which includes some insoluble soap is very desirable for use in connection with containers to which steam is to be applied for sterilization purposes, because, due to the increased viscosity of the wax composition and its high melting point, the coating on the container will not tend to melt or soften. When the coating has re-cooled the container is still rendered waterproof throughout, since the coating is not displaced under heat.

' Soluble soaps, such a sodium and potassium soap, are not usually so desirable in a wax composition, particularly when used in any substantial quantity, because if the composition is to be applied to any surfaces which are to be waterrepellent the presence of a substantial amount of a water soluble soap is not desirable.

Furthermore, in order to incorporate the soluble soaps, such as sodium stearate, in wax compositions, they should be substantially dry on account of the fact that sodium stearate, for example, melts at 400 F., and the wax composition must be at this temperature, or above, to obtain hydrogenated glycerides, in that they combine with' such compounds to make a homogeneous a homogeneous mixture.

As a specific example of the present invention,

about 2.5% of anadditive base. comprising approximately equal parts of a hydrogenated mix ture Of vegetable glycerides having a Titer test about 65 C. and magnesium stearate was added to about 97.5% of unrefined scale waxes having a melting point in the region of 123 F. The melting point of the resultant wax composition was in the region of 178 F. and the tensile strength, ductility and water-repellent characteristics were greatly improved. Addition of about of the above additive composition raised the melting point of the scale waxes to the region of 193 F., as well as improving the other physical properties, while the addition of about 7.5% further raised the melting point to approximately 195 F., and again the tensile strength, ductility and water-repellent characteristics of the resultant wax composition showed a marked improvement. Illustrative of the effect of the additive base on tensile strength, crude scale wax having a tensile strength of lbs. per square inch has a tensile strength of about 57 lbs. when 2.5% of the base is present. With 5% present, the tensile strength increases to about 73 lbs., and with 7.5%, it is approximately 75 lbs.

When about 5% of an additive base comprising approximately equal parts of hydrogenated castor oil and magnesium stearate was added to about 95% of the crude scale waxes, the melting point of the waxes was raised to about 175 F. Excellent physical properties, including high tensile strength, toughness and ductility, were obtained.

Of course, the amount of additive base used to improve the properties of mineral waxes is dependent upon the increase in melting point desired, and also upon the type of wax being modified. To improve slack waxes which have lower melting points than scale waxes it may be necessary to add ,a considerably larger percentage of the additive composition in order to secure a relatively high melting point and a relatively high tensile strength, and the like.

Another feature of the improved wax compositions disclosed herein is their ability to form stable emulsions. The addition of a hydrogenated glyceride of animal or vegetable fats and oils, together with an insoluble fatty acid soap, to wax tends to cause the wax composition to be more easily emulsified. A much smaller percentage of emulsifier, such as, for example, triethanolamine stearate, may be used than is ordinarily required to emulsify unmodified paraffin wax. When triethanolamine stearate is used as an emulsifier a stable emulsion of wax composition may be produced, which emulsion may be shipped or stored for substantial periods of time without separation or decomposition.

Furthermore, such emulsions may be formed with from a minimum amount of water, such as 10% or so, up to a water content of 90% or so. Also, emulsions of wax, together with the addition of compositions disclosed herein, have the property of remaining homogeneous when heated. For example, When initially made an emulsion comprising about 21.75% of a wax composition embodying the present invention, about 3.25% triethanolamine stearate, and about 75% water, is creamy white and has the consistency of a hard cup grease. When heated up to above the boiling point of water, the emulsion is not destroyed but becomes thinner and less viscous. Upon cooling it is stable and is slightly stiffer than it was before heating.

More interesting, however, is the fact that this emulsion has the characteristic of higher penetration, than heretofore obtainable with wax which it is applied, such as sheets of paper, more.

rapidly'and to much greater extent than heretofore.' Due to the fact that it is stable when hot, it is possible to add the emulsion directly to a hot mix of paper pulp.

With emulsions formed according to my invention it is even possible to add them to hot paper pulp suspensions containing large percentages of Water without making the emulsion 'unstable. It forms a dilute milky liquid appearing to have the characteristics of a solution, and the paper pulp will be impregnated with the wax emulsion, uniformly dispersed therethrough. The paper, when formed into sheets, thus contains the wax in intimate association therewith.

It willalso be seen that 'by forming a stable wax emulsion with a small amount of water or a large per cent of water it is possible to more readily control the amount of wax to be added to .a given amount of paper, either while in the pulp stage or after sheets have been formed. Also, by causing a uniform dispersion of the wax a given amount of wax will impregnate or coat more paper.

In the paper industry these Wax compositions may be readily used to impregnate or coat many kinds of paper and paper products. Papers and paper products coated with compositions described above are greatly improved because the waxy film adheres very tightly to the paper surface, does not easily become tacky and is very durable due to its toughness, tensile strength, ductility, etc. The grain size of such a film is very fine, and impregnated or coated papers are rendered highly impervious to moisture, even when subjected to moisture over extensive periods of time.

Wax emulsions embodying the invention disclosed herein may be made without dimculty by bringing the wax to a temperature slightly above the melting point and adding water thereto in the desired amount. composition contain an emulsifier, no emulsifier need be present in the water. On the other hand, if no emulsifier is present, then triethanolamine stearate or some other emulsifier may be dissolved in the water in the desired amount. The water is preferably at the same temperature as the melted wax composition and they are mixed and stirred until the temperature falls to just below the solidifying point of the wax, at which time an emulsion forms and stirring is no longer necessary. Stable emulsions hav been made with as little as 8% or 9% wax composition, 1% or so of triethanolamine stearate, and the balance water. On the other hand, stable emulsions can be made by using 70% wax, 20% water and 10% triethanolamine stearate.

It will be seen from the above examples that emulsions of the wax composition disclosed herein can be made with a very small amount of water, or Water in amounts up to or more,

and such compositions are stable and may-be utilized in many industries.

Although the emulsions described above have been made by the use of an emulsifier, such as triethanolamine stearate, it is contemplated that many other emulsifiers may be used, whereby emulsions of various other types will be obtained.

The improved wax compositions described herein may be made by directly mixing the in- If the wax and additive known as a homogenizer.

or the melted wax may be poured onto the additive composition. ciently stirred or agitated to make it homogeneous.

The physical properties of the improved wax compositions may be further enhanced ii the. ingredlents are caused to be intimately contacted with each other throughout large areas. The desired intimate contact'may be obtained by mixing the ingredients in a type of colloidal mill Such a machine may be of the type in which the substances to be mixed are melted and fed in the desired proportions, such that they are caused to flow in a thin, continuous film over a swiftly rotating surface. The mixed substances are preferably admitted-in a'iimited or controlled manner to the central portion of a disk or plate rotating at a relatively high speed, so that the mixture will be projected over the surface in a film of extreme thinness and subsequently collected.

Due to the intimate association of the ingredients or the additive composition and the waxes effected by the use of a homogenizer, smaller amounts of the additive base may be used to get the same improved physical properties of the wax composition, or with the same amounts or additive base considerably greater improvements in the physical properties of the wax composition will be obtained by efiecting intimate association of the ingredients in a homogenizer. For example, homogenization of a wax composition embodying the present invention may effectan increase in the melting point of about 20 to 30 F. or so above the melting point obtained after manual agitation. Of course the tensile strength, ductility, and the like may also be'improved in this manner. This is believed due to the intimate contact of the ingredients throughout large areas.

As mentioned above, wax compositions embodying the present invention may readily be emulsified to produce relatively stable emulsions which may stand for a considerable period 01 time without separation. These emulsions may also be made efficiently and economically by the use of a colloidal mill of thetype mentioned, and the properties are improved in a manner corresponding to the improvements obtained by treating the wax compositions as described above.

By way of illustration, the improved wax compositions may be made so that they contain an emulsifier, triethanolamine stearate having already been'described as suitable. Such a composition may be melted, mixed with hot water and projected in an extremeiy'thin film over a swiftly rotating surface.

The product obtained is a creamy, white emulsion, which may be shipped as produced and sub- The mixture should be suifldered sterile by treatment with steam prior to placing contents therein, .without injuring the improved water-repelling. properties'of such'containers.

Wax compositions embodying the present inventionare also valuable, in that they are stable and do not oxidize, retaining their improved physical properties over long periods of time.

' high water-repellency.

Another feature 01' the wax compositions described here is that when two surfaces thereof come into contact they do not. adhere, being readily separable. This is of value because blocks or cakes of the above wax compositions may be shipped while in contact with each other, and easily separated thereafter. The adherence of contacting blocks or cakes of pure parafilnis a disadvantage commonlyencountered. The additive composition or base, comprising an ingredient which has the-ability to raise the'melting point or waxes and an ingredient to improve the otherphysical properties of wax, is a'valuable product in itself. Its composition is-such that it is similar to many natural waxes, such as candelila, Japan wax, camauba, beeswax, and the like, and in many industries .it may be used in conjunction with, or as a substitute for, many of these more expensive waxes.

Furthermore, it is to be understood that variations and modifications of the specific examples given for purposes of illustration and explanation may be made without departing from the spirit of the invention.

What I claim is:

1. A wax composition having improved properties which comprises less than approximately 10% of hydrogenated glycerides, less than approximately 10% of a metallic fatty acid soap, and the balance mineral wax, said composition being characterized by its fine grain, increased tensile strength, increased melting point, and

2. A wax composition having improved properties which comprises less than approximately 10% of a hydrogenated mixture 'of glycerides, less than about 10% or an alkali metal fatty acid soap, and the balance mineral wax, said composition being characterized by its line grain, in-

- creased tensiie strength, increased melting point,

sequently further diluted with water, if desired.

positions of the type disclosed herein may be used advantageously in a great many industries because of their improved physical characteristics. As .on illustration, they may be readily used in coating containers and the like, because they may be made to have a meltingpointsufiiciently high that such containers maybe renand high water-repellency.

3. A wax composition .havingimproved properties which comprises less than about 10% of a hydrogenated mixture of fishoils, less than about 10% of a metallic soap of stearic acid, and 'the balance essentially mineral wax, said composistrength, increased melting point, and high' water-repellency.

5. A wax composition having improved prop erties which comprises less than about 10% of hydrogenated castor oil, having a titer test of from about 60 C. to about 69 C'., less than about 10% of an insoluble soap of stearic acid, and the balance .mineral wax, said composition being characterized by its fine grain, increased tensile strength, increased melting point, and high water-repellency.

Aparaflln base wax composition having im proved tensile strength, high melting point, line grain structure, and increased water-repellant characteristics, which comprises up to 1% of a free higher fatty acid, and a mixture of around equal proportions of hydrogenated glycerides, having a titer test of at least 60 C., and calcium stearate, with the balance essentially of solid parafiins, said mixture of hydrogenated glyceride and calcium stearate being present in an amount up to 10% of said parafllns.

8. A- paraflin base wax composition having improved tensile strength, high melting point, fine grain structure, and increased water-repellant characteristics, which comprises up to 1% of a free higher fatty acid, and a mixture of around equal proportions of hydrogenated castor oil, having a titer test of at least 60 C., and calcium stearate, with the balance essentially of normally solid paraflins, said mixture of hydrogenated castor oil and calcium stearate being present in an amount up to 10% of said paramns.

9. A parafiln base wax composition having improved tensile strength, high melting point, fine grain structure, and increased water-repellant characteristics, which comprises solid paraflins in major proportion, a hydrogenated glyceride and an insoluble metal soap, said hydrogenated glyc eride and said soap being present in an amount up to 10% of said parafflns.

10. A wax base composition having improvedtensile strength, high melting point, and iiicreased water-repellant characteristics, which comprises normally solid parafilns in major proportion, a small amount of a free higher fatty acid, up to 10% of a mixture of a water-insoluble soap of higher fatty acids and at least one member of the group consisting of higher fatty acid glycerides and hydrogenated glycerides, said composition when in solid form at normal temperatures being characterized by a finer grain structure and higher tensile strength than have compositions of the same melting point, but containing only said glycerides or said soap alone.

11. A wax base composition having improved tensile strength, high melting point, and increased water-repellant characteristics, which