US2261985A - Fibrous tube - Google Patents

Description

Patented Nov. 11, 1941 2,261,985 ,rmaous Tuna 'Albert E. Forster, Wilmington, DeL, asslgnor to Hercules Powder Company, Wilmingto n, Del

a corporation of Delaware No Drawing. Application January 11, 1940, Serial No. 3l3,377

s cut-um (cl. 138-76) This invention relates to fibrous tubes and more particularly to impregnated fibrous tubes suitable for use as temporary bore hole casings and as pipes for fluids.

An object of the present invention is to provide inexpensive impregnated fibrous tubes which are light in weight and are relatively strong and rigid.

Another object to provide impregnated fibrous tubes which resist moisture for a period 01' time and then are adapted to become saturated and deteriorate.

A mrther object is to impregnate fibrous tubes with atemporary moisture-proofing composition 3:315:15 readily adsorbed by the fibers of the Other and further objects will be obvious upon an understanding of the illustrative embodiment about to be described, or will be indicated in the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in Practice.

- These objects, generally, are accomplished by impregnating tubes formed of paper, cardboard,

pulp board, or similar cellulcsic fibrous materials. preferably having a thickness 01 between'.1 and .2 of an inch, and a diameter of about 3 inches. The impregnating composition, which produces the foregoingdesired results, may consist of a substantially petroleum-hydrocarbon insoluble pine wood resin, or may comprise a mixtureof the resin and bituminous or asphaltic material, such as tar, or, if desired, the composition may comprise a plastic-like reaction product of the resin and an oil, and bituminous or asphaltic material. Also, if desired, a mixture the reaction product and the coal tar may be ployed.

The material which is characterized by the term substantially petroleum-hydrocarbon insoluble pine wood resin, herein and in the appended claims, is the resinous material which may be prepared from pine wood, preferably from stump pine wood, in the following manner. The pine wood, which may or may not have been steamed to remove volatile constituents such as turpentine and pine oil, may be extracted with a coal, tar hydrocarbon such as benzol or toluol, and the extract then freed of volatile constituents, leaving a residue consistingofamixtureofwoodrodnandtheresin used in the present compositions. Extraction of this-mixture with a petrolemn hydrocarbon such as, for example, gasoline, dissolves and removes from the initial coal tar the rosin. abietic acid, a resinous residue remains which is low in abietic acid.

Alternatively, a gasoline solution of the residue hydrocarbon extract may be treated with furfural, and the two layers which form separated, in which case the petroleum-hydrocarbon insoluble pine wood resin is found dissolved in the furfural from which it may be obtained by evaporation of the iurfural.

Another method of producing the resin comprises extracting rosin from' the wood by means of benzol amixture of gasoline and furfural. The gasoline dissolves the rosin while the furiural dissolves the resin. The solvents are then separated and the resin is recovered by evaporation of the fur ural.

This resinous material, used in carrying out the present invention, is characterized by a dark red brown color, cherry red in solution, and by substantial insolubility in petroleum hydrocarbons, but it will vary somewhat in its specific characteristics such as acid number, melting point, exact petroleum ether solubility, and content oi naphtha andtoluol insoluble material, depending upon the details of the extraction process utilized. This resin will meet or-nearly meet the following specifications, namely, substantial insolubility in petroleum hydrocarbons, substantially complete solubility in alcohol, a methoxv content from about 3% to about 7.23% (usually from about 4% to about 6%), an acid number in the range from about to about 110, and a drop melting point in the range from about C. to about C.

The coal tar which is suitable in the composition may be a high boiling coal tar oil or a coal tar pitch.

The oil used in making action product may be a semi-drying oil, such asflsh oil or adrying oil, such-as linseedoil, which preferably can be cooked to compatibility with the resin. Where fish oil hereinafter and in the claims, it is intended to include such semi-dryin or drying oils generally known. If desired, action product, hexamethylenetetramine or formaldehyde is added to assist the partial conversion of the resin to a gel.

The P s nt invention is not intended to be limited to specific proportions of ingredients. It has been found that an impregnating composition consisting only 0! the substantially petroleum hydrocarbon insoluble pine wood resin is After separation of the rosin, high in and treating the extracted rosin with I the plastic-like reis mentioned in preparing the resuitable. This resin may be modified with coal tar. For example, for every ten parts of coal tar between about 1 part and about 90 parts resin may be used. Where the reaction product of the resin with a drying or semi-drying oil is added to about parts coal tar, up to about 40 parts resin, and between 10 and 200 parts reaction product comprise the composition. The reaction product may vary in composition, between about 33% and 70% resin and the balance drying or semi-drying oil to total 100%. A small amount of hexamethylenetetramine or formaldehyde is added to facilitate conversion of the resin.

The following examples illustrate compositions suitable for impregnating fibrous cellulosic tubes to accomplish the objects of the present invention:

Materials (parts by weight) Examples I II III IV V VI Resinfl. 100 -40 40 10 Goal tar oil 10 10 10 Coal tar pitch 90 Reaction product GF. 10 Reaction product FF 10 Reaction product AF 200 Substantially troleum hydrocarbon in soluble pine wood resin GF, a fish oil p astic, 33% resin," partly converted toa gel with hexamethylenetetramine.

FF, 50% resin" with fish oil cooked to convertibility with formaldehyde AF, 70% resin" with fish oil cooked to compatibility.

The impregnating compositions may be pre-.

pared by heat the materials to provide a low melt having a viscosity to facilitate penetration of the fibrous tubes. Preferably, the impregnation of the tubes is carried out in a vessel maintained under a pressure of about 70 pounds per square inch, by the addition of an inert gas, such as nitrogen, while maintaining the temperature of the melt between about 120 and 180 0., but preferably at about 165 C. By impregnating under pressure, the cellulosic fibers are not degraded by the heat of the melt. The tubes thereafter may be removed from the impregnating bath and permitted to drain and dry in a suitable manner.

If desired, the tubes may be coated, impregnated, or saturated by brushing, coating or spraying the compositions thereon or dipping the tubes therein. The amount of material absorbed may be controlled to provide the tubes with any desired degree of water resistance.

The tubes impregnated in the foregoing manner by using the compositions described herein are suitable where a semi-permanent or temporary tubing isv desired. For example, where temporary pipe lines for pumping water are desired at locations such as swamp or marsh land, which are not readily accessible by motor trucks, the tubes, by being light in weight, can be readily carried manually. After the pipe linesare no longer desired, the tubes need not be recovered as would be the case-of more expensive metal pipe, but can be left at the location and upon be ing exposed to. rain and sun will deteriorate.

The. tubes, in accordance with the invention, are also suitable for lining bore holes used for explosive charges in seismic prospecting. Here again the tubes are readily brought on location, are sufllciently strong to keep the bore hole open to permit the desired number of charges to beexploded and can thereafter be abandoned and permitted to deteriorate without becoming a menace to tilling of the soil, or to navigation in the event they are used for lining holes beneath the surface of lakes or bays.

The tubes so impregnated may be of any suitable design. For example, tubes formed of spirally woundstrips may be used. The impregnating composition serves to strengthen the joints of the strips and serves to prevent unravelling thereof.

It will be understood that the details and examples hereinbefore set forth are illustrative only and thattheinvention as broadly described and claimed is in no way limited thereby.

What I claim and desire to protect by Letters mixture comprising coal tar and a material selected from the group consisting of a substantially petroleum-hydrocarbon insoluble pine wood resin, and reaction products of said resin with a semi-drying oil.

3. A tube of the class described composed of fibrous cellulosic material impregnated with a substantially petroleum hydrocarbon insoluble pine wood resin.

4. A tube of the class described composed of fibrous cellulosic material impregnated with a mixture consisting of coal tar and a substantially petroleum-hydrocarbon insoluble pine wood resin.

5. A tube of the class described composed of fibrous cellulosic material impregnated with a mixture comprising coal tar, and a reaction product of a fish oil and a substantially petroleumhydrooarbon insoluble pine wood resin.

6. A tube of the class described composed of fibrous cellulosic material impregnated with a mixture consisting of ,a coal tar, a substantially petroleum-hydrocarbon insoluble pine wood resin, and a reaction product of said resin and a fish oil.

ALBERT E. FORS'IER.

DISCLAIMER 2,261,985.Alber E. Forster, Wilmington, Del. FIBROUS TUBE. Patent dated N ovemlier 11, 1941. Disclaimer filed May 11, 1943, by' the essignee, Herc'iles Powder C'ompany,

Hereb enters this disclaimer to-esmuch of claim 1 as will include a substantially petrol'eumydrocarbon insoluble pinewood resin as the impregnating material; and

to claim 3 in said patent..

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