US2304304A - Defoamer - Google Patents

Description

atented James H. Fritz, Bloomfield, N. .l., assignor to National il Products Company, Harrison, N. .l., a. corporation of New Jersey No Drawing. Application y 31, 1939, Serial No. 276,555

lDllaims.

fibers are caused to go over the screens with the tailings. In some plants devices known as rif flers, which consist of long troughs having a series of pockets in the bottom thereof, are employed to remove impurities from the pulp slurry by passing the slurry through the rifilers, the impurities such as dirt, etc., being heavier than the desired pulp and settling into the pockets. However, foaming is likely to occur in the rifflers so that the dirt and like material is entrained in the foam and does not settle into the pockets; the foam also causes the fibers to float on the surface of the slurry, thus hindering dirt removal and destroying the uniform consistency of the slurry. When the pulp is washed, a relatively large amount of foam results which lowers the eficiency of the washers, and the foam may build up to such an extent as to overflow from the washers onto the floor. manufacture of pulp where foam presents a problem is at the sewer pipes for disposal of waste water where sufiicient foam may collect so that it is impossible to-dispose of the waste down the sewer.

In the manufacture of paper, foaming tends to take place wherever the stock is agitated. The most serious foaming occurs at the screens and on the paper machine. As pointed out above, the presence of foam in screening operations lowers the screening eficiency and causes acceptable fibers to be lost in the tailings. With regard to the machines, if a cylinder paper machine is employed, foam develops in the vats thereof, causing the formation of an uneven paper product and loss of fibrous material due to the overflow of the foam from the vats. In the Fourdrinier machines foam appears on the pond and this foam has a tendency to break and go over the wire, thereby causing the formation of dirty paper. i

From the above discussion, it is evident that eficient and inexpensive agents capable of preventing or abating foam and of destroying existing foam are highly desirable for use in the manufacture of pulp and paper. While there are Another point in the vention is a partial a considerable number of defoaming agents now on the market, there is still a great demand in the pulp and paper industries for inexpensive defoaming agents having improved defoaming action.

It is the object of this invention to provide inexpensive and highly eflicient defoaming agents for use in the manufacture of pulp and paper.

I have now found that aqueous emulsions of mineral waxes upon addition thereof to slurries and suspensions of fibrous material produced in the manufacture of pulp and paper effectively,

prevent or abate the formation of foam wherever it tends to develop in the slurries and suspensions and destroy existing foam after it has formed thereon. These emulsions are preferably formed by'emulsifying a mineral wax in an aqueone medium employing a partial glyceride of a higher fatty acid as an emulsifying agent. The term "partial glyceride of a higher fatty acid is intended to include mono and di glycerides of higher fatty acids: in view of the close similarity of the naphthenlc aclds'to the higher fatty acids,

the naphthenicacids are included for the pur-.

poses of this application within the term higher fatty aci The emulsions of mineral waxes prepared in accordance with my invention have been found to be extremely efiective defoaming agents for use in the manufactureof pulp and paper; furthermore, these emulsions are very-inexpensive and easy to prepare.

The defoamlng agents of my invention may comprise any mineral wax such-as paraffin wax or petrolatum wax. I prefer to-employ paraffin wax because of its ready availability and comparatively low pricejfurthermore, emulsions of parafin wax are excellent defoaming agents. However, it is to beunderstood other mineral waxes may be employed if desired.

As pointed out above, the emulsifying agent preferably employed in accordance with my inglyceride of a higher fatty acid; thus, for example, the mono and di glycerides of stearic acid, oleic acid, rlcinoleic acid, llnoleic acid, palmitic acid, myristlc acid,-lauric acid, capric acid, naphthenic acid, etc. may be employed. The partial glycerides not only act to emulsify the mineral wax in the aqueous medium, but they also possess inherent defoaming properties and thus tend to improve the defoaming characteristics of the emulsions of my invention. I have found that emulsions of the partial glycerides of higher fatty acids containing no mineral wax may be used in the manufacture of pulp andpaper to prevent or abate the formaadded to the stock just ahead of tlon of foam or to destroy existing foam, but more efl'ective defoaming agents are obtained if mineral waxes are also included in the emulsions.

The preferred agents of my invention may be prepared by melting together the non-aqueous constituents of the emulsion, i. e., the wax and the partial glyceride and any other substance it is desired to include in the emulsion and then adding to the molten mass as much water as desired with continuous agitation until a substantially homogeneous emulsion is obtained. Preferably, the emulsions added to slurries and suspensions of fibrous material produced in the manufacture of pulp and paper, in accordance with my invention, contain between about 0.12% and about 1.5% of the mineral wax, and between about 0.25% and about 2.5% of the partial glyceride, the balance being water. However, it is to be understood that, if desired, emulsions containing a much greater quantit of mineral wax and partial glyceride may be prepared and these emulsions then diluted before use; it is advantageous to prepare relatively concentrated emulsions if it is desired to transport the emulsions or store them for any substantial period of time. It is further to be understood that other substances may be mixed with the emulsions of my invention, which, when properly blended, enhance the defoaming properties of the agent as a whole. Such substances include animal and vegetable oils, fats and waxes, such as teaseed oil, olive oil, castor oil, tallow, wool grease, sperm oil, montan wax, etc., as well as derivatives of these and other fatty substances, such as fatty acids, fatty alcohols, fatty amines, fatty amides, mineral oils and the like. In some cases it may be advantageous to incorporate sulfonated or phosphated derivatives of these substances in the emulsions.

The defoaming agents of my invention may be employed to destroy foam which has developed on the suspensions or slurries produced in the manufacture of pulp and paper, and also to prevent or abate the formation of foam on these slurries and suspensions; the term is thus intended to include both these actions. The emulsions of my invention are preferably the point at which the foaming has occurred or is likely to occur. The term stock is used herein in a broad sense to mean any water suspension of fibers produced in the manufacture of pulp and paper, thereby including pulp, wholestuif, halfstuif and similar aqueous suspensions of fibrous material. The amount of defoaming agent added depends upon the quantity of foam and the type of foam that occurs and generally will vary widely with the particular conditions of operation; however, it is a simple matter for one skilled in the art to adjust the amount of defoaming agent added in order to produce the desired results. In every case I have found that the addition of my novel defoaming agents to slurries and suspensions of fibrous material produced in the manufacture of pulp and paper causes substantially immediate removal of the foam, if foaming has already taken place, or effectively prevents or abates the formation of foam Where there is danger of its occurrence.

From the above description it will be evident that my invention provides a new and highly effective defoaming agent for use in the manufacture ofpulp and paper. It will further be evident from the above description that because of the relative cheaoness of the materials emdefoaming" pioyed in the preparation of my products, defoaming agents readily available to the trade are obtained. Therefore, my invention constitutes an important advance in the art of manufacturing pulp and paper.

Since certain changes may be made in the above compositions of matter and different embodiments of the invention could be made without departing from its scope, it is intended that all matter contined in the above description shall be interpreted as illustrative and not in a limiting sense.

Having described my invention, what I claim as new and desire to secure by Letters Patent, is

l. A. composition of matter comprising a suspension of fibrous material such as is produced in the manufacture of pulp and paper and a defoamer comprising a mineral Wax and a partial glyceride of a higher fatty acid, said defoamer being present in sufficient amount to inhibit the development of foam upon the surface of said suspension.

2. A composition of matter comprising a suspension of fibrous material such as is produced in the manufacture of pulp and paper and a defoamer comprising paraffin wax and a partial glyceride of stearic acid, said defoamer being present in sufiicient amount to inhibit the development of foam upon the surface of said suspension.

3. A composition of matter comprising a suspension of fibrous material such as is produced in the manufacture of pulp and paper and a defoamer comprising paramn' wax and a partial glyceride of oleic acid, said defoamer being present in sufficient amount to inhibit the develop. ment of foam upon the surface of said suspen- $1011.

4. A composition of matter comprising a suspension of fibrous material such as is produced in the manufacture of pulp and paper and a defoamer comprising paraffin wax and a partial glyceride of palmitic acid, said defoamer being present in sufficient amount to inhibit the development of foam upon the surface of said suspension.

5. A composition of matter comprising a suspension of fibrous material such as is produced in the manufacture of pulp and paper and a defoamer comprising a mineral wax, a partial glyceride of a higher fatty acid and a mineral oil, said defoamer being present in sufiicient amount to inhibit the development of foam upon the surface of said suspension.

6. A composition of matter comprising a suspension of fibrous material such as is produced in the manufacture of pulp and paper and a defoamer comprising a mineral war, a partial glyceride of a higher fatty acid and asulfonated fatty substance, said defoamer being present in sumcient amount to inhibit the development of foam upon the surface of said suspension,

7. In the manufacture of pulp and paper the improvement which comprises incorporating in the suspension of fibrous material a relatively small amount of a defoaming agent comprising a mineral wax and a partial glyceride of a higher fatty acid, said defoaming agent being incorporated in sufficient quantity to inhibit foaming upon the surface of said suspension.

8. In the manufacture of pulp and paper the improvement which comprises incorporating in the suspension of fibrous material a relatively small amount of a defoaming agent comprising higher fatty acid, the balance being substantially all water.

10. A composition for defoaming pulp and paper stock comprising approximately from .12 to I 1.5 percent of paraffin wax and approximately from .25 to 2.5 per cent of a partial glyceride of a higher fatty acid, the balance being substantially all water.

JAMES H. FRITZ.