US3140974A - Compositions and processes for the treatment of fourdrinier wire cloths of papermaking machines - Google Patents

Description

Unite States atent 3,140,974 COMPOSITIONS AND PROCESSES FOR THE TREATMENT OF FOURDIER WEE CLQTHS F PAPERMAG MACHINES John D. Pera, Fred W. Baths, and Robert F. Drescher, Memphis, Tenn., assignors to Bushman Laboratories, Inc, Memphis, Tenn, a corporation of Tennessee No Drawing. Filed July 3, 1961, Ser. No. 121,383 12 Claims. (Cl. 162-199) The present invention relates to compositions and processes for the treatment of Fourdrinier wire cloths composed of strands of copper-containing alloys that are used in papermaking machines, particularly to processes of treating such wire cloths to provide protection from mechanical wear, to which the wires of such machines are normally subjected, and thereby increase the useful life of such wire cloths.

Studies which have been made to determine factors that influence the life of Fourdrinier wire cloths on papermaking machines reveal that the two main factors that influence the useful life of such cloths are actual damage to the Wire and mechanical wear; corrosion, as such, is generally regarded as a factor of lesser importance than these two other factors.

The process of making paper consists of three fundamental operations, namely, hydration of cellulosic fibers with water to form a slurry of pulp and water, the deposition of the fibers of the pulp and formation of a sheet of paper therefrom on a Fourdrinier wire cloth and, finaL ly, dehydration of the paper sheet thus formed. In such processes, a cellulosic pulp and water slurry combined with other papermaking ingredients, which is called the furnish, is added to the headbox of a Fourdrinier machine to provide a continuous supply of the furnish to the machine. The headbox functions in such a way as to provide a homogeneous dispersion of the furnish flowing continuously in a relatively non-turbulent manner through the slice of the headbox (an opening extending across the entire width) onto a Fourdrinier wire cloth. The Fourdrinier Wire cloth carries the furnish from the breast roll adjacent the headbox forward to the couch roll, at which point the newly formed paper web or sheet is transferred to other sections of the machine in which water is gradually removed from the formed paper sheet. The endless Fourdrinier wire cloth then returns to the breast roll where it again receives additional amounts of furnish from the headbox.

The function of the Fourdrinier wire cloth is to support the mass of furnish until suflicient water has been removed from the wet paper sheet deposited thereon, so that the sheet has .suiiicient strength to support its own weight without breaking. Additional devices that are used to assist in the removal of water from the newly formed sheet are the forming board, table rolls, suction boxes, and suction rolls. The Fourdrinier wire used commonly includes a warp formed of strands of wires of a Phosphor bronze which is a copper-tin alloy, containing a relatively small amount of tin, such as 7 to 8 percent, with the balance copper, while the shute strands are composed of red brass, which usually contains zinc in an amount of approximately to percent, with the balance copper.

The Fourdrinier wire cloth is supported by and rotates around the breast roll at one end and the couch roll at the other. Between these rolls additional support is obtained by a forming board, a series of table rolls and a series of suction boxes. The Fourdrinier wire cloth is driven by the couch roll and the supplementary drive rolls. Its alignment on the machine is maintained by one or more guide rolls and proper tension of the cloth is maintained by one or more stretch rolls.

Because of the vital function served by the Fourdrinier wire cloth in the papermaking operation, and because it is extremely susceptible to mechanical stresses, abrasion, and other deleterious influences, the wire cloth must be protected from lumps of furnish that may accumulate between the various rolls and the wire cloth and distend the wire cloth. The means most frequently adopted for this purpose is that of providing water showers located at various positions relative to the wire cloth to wash and remove any lumps of furnish that may have collected upon the wire cloth and the wire return rolls.

The care used in the installation of wire cloths on papermaking machines is an important factor influencing the useful life of all such wire cloths. In general, longer and finer mesh wires are damaged more easily than shorter and coarser mesh wires. Damage that can result from careless installation of the wire cloths on papermaking machines includes creasing, as well as damage during operation from downward and upward furnish jams, edge cracks, etc. As suggested by the nature of these problems, the relative importance of damage versus mechanical wear varies from machine to machine. When adequate steps are taken to reduce damage to a minimum, mechanical wear then becomes the principal factor limiting wire life.

The most important factors which contribute to mechanical wear of wire cloths are the drag load exerted by the suction boxes, speed of the wire cloth, and the quantity of abrasive grit present in the furnish as it flows from the headbox on to the wire cloth. Wear occurs primarily on the underside of the wire cloth. It results from pulling the wire cloth at a relatively high rate of speed over the surfaces of the stationary suction boxes to which a vacuum has been applied to facilitate the removal of water from the sheet of paper formed on the surface of the wire. When the surfaces of the suction boxes have grit or other abrasive particles embedded in them, the rate of mechanical wear is further increased. In order to reduce mechanical wear, use of materials other than wood for suction-box covers, reduction of the vacuum applied to suction boxes, and a more complete removal of grit from the paper furnish have been suggested. However, progress on the reduction of mechanical wear of wire cloths has been limited to investigation of factors such as these. The increasing speeds which are gradually being adopted on papermaking machines have made it necessary to consider other means for increasing the useful ife of Fourdrinier wire cloths in terms of days of operation.

One of the objects of the present invention is to provide compositions which when applied to such wire cloths act as anti-wear or wear-inhibiting agents and thereby extend the useful life of such cloths on papermaking machines. Another object of the present invention is to provide processes for the treatment of copper-containing alloy Fourdrinier wire cloths, which will reduce the mechanical wear of such wires on the papermaking machine. Other objects and advantages of this inven- -on the strands by the treatment.

tion, some of which are referred to hereinafter, will be obvious to those skilled in the art to which it pertains.

It has now been discovered that mechanical wear of copper-containing alloy Fourdrinier wire cloths can be reduced by applying directly to the wire cloths or adding to the aqueous fluids with which these wire cloths come into contact, compositions containing a mixture of 2-aminoethanol and an alkali-metal salt of Z-mercaptobenzothiazole. Although neither of these substances when added alone has any significant effect on mechanical wear of such wire cloths, combinations of the two in the range of ratios specified herein reduce the mechanical wear and increase the useful life of such wire cloths. Although mixtures of these substances appear to adhere to or deposit a film upon the individual wire strands of the cloths, the exact mechanism of this unusual action has not as yet been ascertained. However, these substances appear to act as antiwear or wear-inhibiting agents. The film thus deposited not only provides incidental corrosion inhibition, but also increases the resistance of the wire to mechanical wear, erosion, or other effects, as a consequence of which the life of such wires is extended beyond their theretofore useful life.

Mixtures of Z-aminoethanol, which is also commonly known as monoethanolamine and simply as ethanolamine, and alkali-metal salts of Z-mercaptobenzothiazole which 'were found useful for the purposes specified herein are those within the range of ratios between approximately 35 and approximately 60 parts by weight of 2-aminoethanol to between approximately 65 and approximately 40 parts by weight of the alkali-metal salt of 2-mercaptobenzothiazole based on its Z-mercaptobenzothiazole equivalent. A preferred composition is an aqueous solution containing equal parts by weight of Z-aminoethanol and Z-mercaptobenzothiazole as its alkali-metal salt, such as is illustrated in Example 3 hereinafter.

When a Phosphor-bronze wire cloth is immersed in an aqueous solution containing an alkali-metal salt of 2-mercaptobenzothiazole and Z-aminoethanol in ratios within the specified range, and then washed with water, the strands of the wire cloth become coated with a film of the mixture. This film remains even after removing the water. Wire cloth wetted or coated with the film in this manner is more resistant to staining by sulfide ion and corrosion than untreated wide cloths. When the wire cloth is treated with a mixture containing less 2-aminoethanol or less Z-mercaptobenzothiazole than the ratios specified, a lesser amount of film remains on the wire cloth and the wire cloth is itself more susceptible to staining by sulfide ion and to corrosion. In Example 1 hereinafter, in which composition B containing 2-aminoethanol and sodium Z-mercaptobenzothiazole in ratios outside the specified range was used, the useful life of the wire cloth treated therewith was less than that of the wire cloth treated with composition A, which contained amounts of these compounds within the specified range of ratios.

Elemental analysis of strands of copper-containing alloy Fourdrinier wire cloths treated in accordance with the processes of this invention reveal the presence of nitrogen and sulfur. This confirms that a film is definitely formed This film is not readily removable by washing with water and appears to be firmly held.

In the examples which follow a preferred process and composition for practicing the present invention are included.

EXAMPLE 1 Addition of Composition A to the Furnish of a Papermaking Machine The papermaking machine referred to in this example is one that is used to produce newsprint from a pulp consisting of a mixture of groundwood and kraft southern pine pulps. The machine produces a gross headbox tonnage of 270 tons per day. The headbox consistency is 0.7 percent (percentage of parts by Weight of pulp to parts by weight of water). The temperature of the furnish is F. and its pH is 5.0. The endless Fourdrinier wire cloth on this machine during operation travels at a speed of 1,820 feet per minute. This Fourdrinier wire cloth is formed of Phosphor bronze and red brass, having a mesh of 60/46 strands per inch, a width of 213.5 inches and a length of 116 feet 5 inches. These mesh numbers refer to strands per linear inch; the first number refers to Warp strands that run lengthwise, that is, in the machine direction; the second refers to shute strands, running in the opposite direction, namely, crosswise to the machine direction.

An aqueous solution, referred to herein as composition A, which contains the following substances in percentages by weight:

Percent by weight Disodium cyanodithioimidocarbonate 9.4 Ethylenediamine 3.5 Potassium N-methyldithiocarbamate 1&9 Sodium Z-mercaptobenzothiazole 13.8 Z-aminoethanol 12.2

was continuously added to the furnish at the reject screen of the machine at the rate of 0.46 pound per ton of paper produced. This amount of composition A provided a concentration 1.5 ppm. throughout the system continuously. The mixture of composition A commingled with the furnish then flowed from the headbox onto the endless Fourdrinier wire cloth traveling at high speed. Composition A came into intimate contact with the wire cloth during the process of removing water from the sheet formed on the wire cloth.

In the table which follows hereinafter is summarized .the performance of wires on this papermaking machine, some of which were subjected to treatment with the foregoing composition A, and one of which was treated with composition B, a similar chemical composition designed to provide adequate slime control and to reduce the darkening of Fourdrinier wires, which consists of an aqueous solution containing the following substances in percentages by weight:

Percent by weight Disodium cyanodithioimidocarbonate 10.0 Ethylenediamine 3.7 Potassium N-methyldithiocarbamate 13.7 Sodium Z-mercaptobenzothiazole 14.7 Z-aminoethanol 6.5

Composition B, which contains the same components as composition A, but contains a smaller ratio of Z-aminoethanol to sodium Z-mercaptobenzothiazole, had no appreciable effect on the useful life of the Fourdrinier wires. The wire that had been subjected to treatment with composition B is included in the table only to provide a basis of comparison.

Each of the wires included in the performance data tabulated hereinafter were kept in continuous use on the papermaking machine until they were no longer usable. The number of days specified in the third column of this table represents the maximum period of useful performance or life which each wire provided on this machine before replacement was necessary.

As shown in the foregoing table, composition A increased the useful life of the wire cloths on this machine by as much as 32 percent.

EXAMPLE 2 Application of Composition A to the Wire Cloth Through the Wire Showers of a Papermaking Machine The papermaking machine referred to in this example is used to produce light, medium, and heavy-weight grades of kraft paper, unbleached kraft liner board, also unbleached kraft pulp. Its normal production is 300 tons per day. The headbox consistency of the furnish varies from 0.2 to 0.5 percent. The temperature of the furnish in the headbox is approximately 110 F. and its pH is usually between 5.0 and 6.0, but when the machine is used to produce unbleached kraft pulp, the pH may be as high as 8.0. The endless Fourdrinier wire cloth on this machine travels at speeds between 1,000 and 1,750 feet per minute, although most of the time the machine is operated at a speed between 1,500 and 1,600 feet per minute.

The wire cloths used on this machine are 138 feet 11 inches long and 264 inches wide. Only one out of every four wire cloths used on this machine has a mesh of 60/48, the machine being more frequently used with cloths having a mesh of 60/49. The type of Wires used are exemplified by the following composition: shute wire, alloy containing 85 percent copper and 15 percent zinc; warp wire, alloy containing 92 percent copper and 8 percent tin.

Composition A, whose composition is specified in Example 1 hereinbefore, was fed at the rate of 1.2 pounds per ton of paper produced into the water flowing through six wire showers. Each of these wire showers was located inside the endless wire cloth and between the breast and couch rolls, extended across the entire width of the wire, and discharged streams through nozzles that impinged onto the underside of the wire cloth as it returns from the couch to the breast roll. Water having a pH of 7.0 and a temperature of 110 F. was used in these six showers at the rate of 1,000 gallons per minute.

In this example, composition A was first injected into the water flowing through all six showers in such amounts that the water impinging on the wires contained ppm. of composition A. Six consecutive wire cloths (numbered 17 to 22 in the table hereinafter) were treated continuously in this manner during the operation of the machine. Thereafter, in connection with two wire cloths (numbered 23 and 24) composition A was added only to the water supplying the last three showers, those nearest the breast roll, in an amount such as to provide 60 ppm. of composition A in the shower water impinging on the wire cloth.

The results reported in the table which follows represent the number of linear feet which each wire cloth travelled on the machine during papermaking operations before it was replaced. Wire cloths numbered 17 to 24 had been treated by addition of composition A to the shower water in the manner described hereinbefore, while wire cloths numbered 1 to 16 had been treated with composition C, which was an aqueous solution containing the following ingredients in the specified percentages by weight:

Percent by weight Disodium cyanodithioimidocarbonate 12.7 Ethylenediamine 4.8 Potassium N-methyldithiocarbamate 17.5

The additions of composition C were made at a rate of 4 ppm. for a period of 6 hours daily to the papermaking machine at the fan pump from which the furnish flowed onto the Fourdrinier wire cloth through the headbox. The average footage travelled by each of the 16 wires treated with composition C was 17,369,176 feet. When Total foot- Wire Cloth N0. Treatment age run 1 Composition 0 23, 497, 710

EXAMPLE 3 A pplidation of Composition D Through the Wire Showers 0 a Papermaking Machine The papermaking machine referred to in this example is the same as that referred to in Example 2 hereinbefore, and wires of similar composition were used on this machine.

Composition D which was used in this example is an aqueous solution containing the following ingredients in the specified percentages by weight:

Percent by weight Sodium Z-mercaptobenzothiazole (based on its 2- mercaptobenzothiazole equivalent) 26.0 Z-aminoethanol 26.0

Composition D was fed into the water supplying the two wire showers nearest the breast roll at a rate of 1.04 pounds of composition D per ton of paper production, which corresponds to a concentration of 78 ppm. of composition D (or approximately 40 ppm. of 2-aminoethanol and Z-mercaptobenzothiazole) in the shower water.

One Fourdrinier wire cloth that was thus treated had a useful life of at least 31,000,000 feet, which represents an increase of at least 78.5 percent over 17,369,176 feet, which is the average footage of the wires referred to in Example 2 that had been treated with composition C.

A second similar Fourdrinier wire cloth treated in the same manner with composition D had a useful life of 39,254,000 feet, which represents an increase of 126 percent, even though this wire had been damaged by crimping when it was installed on the machine.

Composition D referred to in Example 3 is a fluid composition that represents a convenient form in which the mixture of alkali-metal salt of Z-mercaptobenzothiazole and Z-aminoethanol may be dispensed and used in such papermaking operations. The application of the mixture directly to the wire cloth through the wire showers is also regarded as a preferred method of treating the wir in accordance with the processes of this invention.

EXAMPLE 4 Composition E A composition was prepared by mixing 41.4 grams of an aqueous solution containing 10.1 grams of disodium fluids circulating in the machine. vis applied directly as an aqueous solution to the wire be- -cyanodithioimidocarbonate with 26.4 grams of an aqueous solution containing 13.8 grams of potassium N-methyldithiocarbamate and 3.7 grams of ethylenediarnine. To the resulting solution were added 13.0 grams of Z-arninoethanol, 13.0 grams of Z-mercaptobenzothiazole, and 2.4 "grams of sodium hydroxide. The clear, orange-colored solution thus obtained may be used in paper machine systems in the same mannersas described in the other examples herein.

EXAMPLE f f' ff Application of Composition A to the Wire iCloth Through the Wire Showers of a Papcrmaking Machine The papermaking machine referred to inthis. example is used to produce 9-point corrugating medium at a normal production rate of 220 tons per day. The headbox consistency of the furnish is 1.0 percent. The temperature of the furnish in the headbox is approximately 120 F. and its pH is usually 8.0. The endless Fourdrinier wire cloth on this machine travels at a speed of 845 feet per minute.

The wire cloths used on the machine are 110 feet 9 inches long and 190 inches wide and have a mesh of 56/34. Both the warp and shute wires were composed of all bronze alloy.

Composition A, whose composition is specified in Example 1 hereinbefore, was added to the wire pit, the fluids from which are reused in the preparation of the furnish, in a slug dose of 25 pounds when the wire was first installed on the machine and fed continuously thereafter at the rate of 0.5 pound per ton of paper produced into the water flowing through a single wire shower. This Wire shower was located inside the endless wire cloth between the breast and couch rolls and extended across the entire width of the wire. The stream from the shower discharged through nozzles that impinged onto the underside of the wire cloth as it passed a return roll on its return from the couch to the breast roll. The water used in the shower was untreated lake water having a pH of 5.5 to 6.0 and which had no buffering capacity, so that the solution of composition A in this water produced an alkaline pH in the shower water. The shower delivered 250 gallons per minute at a pressure of 110 psi. and the concentration of composition A was thus 37 ppm. in the shower water. 7

Composition C, whose composition is specified in Ex- It was fed at the rate of 0.5 pound per ton at the wire pit for a period of '6 hours each day and thus was present at a concentration of 2.5 p.p.m. based on the weight of the aqueous fluids in the system.

The average useful life of wire cloths thus treated with composition C was 14 days while the useful life of the wire thus treated with composition A was 26 days. The useful life of the wire cloth was increased by 86 percent when the treatment with composition C was substituted for the treatment with composition A.

The foregoing examples comprise preferred embodiments of the invention which were selected merely for purposes of illustration. The potassium and other alkalimetal salts of Z-mercaptobenzothiazole may be used in place of the sodium salt in equivalent amounts. The 2- aminoethanol and alkali-metal salt of 2-mercaptobenzothiazole may be added separately or in admixture with each other to any of the units of a papermaking machine provided with copper-alloy Fourdrinier wire cloth and in amounts so as to provide a concentration on the Wire sufflcient to form an adherent film on the individual strands. This normally will be an amount in excess of 0.5 ppm. by weight of the mixture based on the weight of aqueous Preferably the mixture fore it is installed on the machine. The film thus deposited is then maintained and replenished by further additions of the composition to the wire shower water or to a special shower provided for direct application to the wire duringoperation of the machine. The concentration of the mixture which would preferably be used in the special shower would be at least 40 parts per million of the mixture in the shower water and need not exceed 5.0 percent generally speaking.

Compositions A, B, C, and E, each of which contain a mixture of disodium cyanodithioimidocarbonate, ethylenediamine, and potassium N-methyldithiocarbamate, are useful components of compositions for the purpose of controlling slime and iron bacteria in paper-making operations, as described in US. Patent No. 2,929,758. The use of compositions containing these chemical compounds for this purpose, however, may in some instances produce darkening of the Fourdrinier wire cloth by formation of a black copper sulfide deposit or film on the surface of the strands of the Wires. In extreme cases, such films of copper sulfide may partially plug or clog the openings of the Fourdrinier wire cloth, thereby reducing the rate at which water drains therethrough. This Wire darkening can be inhibited by the addition to such compositions of Z-aminoethanol and an alkali-metal salt of Z-mercaptobenzothiazole. However, when Z-aminoethanol and an alkali-metal salt of Z-mercaptobenzothiazole are added to such compositions in amounts conforming to the ratios specified herein, not only will the darkening be inhibited, but the useful life of such wires will be extended as described herein. The additional components present in such compositions appear not to affect or decrease the inherent power of the mixture of 2-aminoethanol and alkali-meta1 salt of 2-rnercaptobenzothiazole to extend the useful life of such Fourdrinier wire cloths. Moreover, the microbiocidal activity of such additional components appears not to be adversely affected 'by admixture with the Z-aminoethanol and alkali-metal salt of Z-mercaptobenzothiazole.

In addition to the foregoing compositions, useful compositions that contain some but not all of the foregoing ingredients in addition to 2-aminoethanol and alkali-metal salt of Z-mercaptobenzothiazole in the amounts specified herein are included within the scope of this invention.

'These compositions may contain as additional components only a water-soluble salt of cyanodithioimidocarbonic acid, or a water-soluble salt of an N-monoalkyl-substituted dithiocarbamic acid, the alkyl radicals of which have fewer than four carbon atoms, or a mixture of the watersoluble salt of cyanodithioimidocarbonic acid and ethylenediamine or other diaminoalkane having not more than six carbon atoms in which the amino substituent radicals are on adjacent carbon atoms in an amount conforming to a molecular ratio not substantially in excess of 1.5

moles of the diaminoalkane to each mole of the cyanodi- .thioimidocarbonate, for example, such compositions as tion that are useful for the purposes specified herein may consequently be regarded as aqueous solutions containing the following components in amounts falling within the range of percentages by weight specified for each in the following table. The last three components are, as stated hereinbefore, desirable components but all three or one or more of them may be omitted as indicated by the intended use of the particular composition.

acid 8-25 Ethylenediamine or other diaminoalkane as specified 3-10 Water-soluble salt of N-methyldithiocarbamic acid or other N-monoalkyl-substituted dithiocarbamate as specified 12-40 Inasmuch as the foregoing specification comprises preferred embodiments of the invention, which were selected for purposes of illustration, it is to be understood that the invention is not restricted to such embodiments, and that modifications, variations, and alternatives, including such as are described or suggested hereinbefore, or which are required to adapt the processes to particular papennaking machines or operations, may be made without departing from the invention, whose scope is limited solely by the appended claims.

What is claimed is:

1. A composition comprising 2-aminoethanol and an alkali-metal salt of Z-mercaptobenzothiazole in amounts conforming to ratios between and 60 parts by weight of Z-aminoethanol to between 65 and parts by weight (based on its Z-mercaptobenzothiazole equivalent) of the alkali-metal salt of 2-mercaptobenzothiazole.

2. A composition of the group consisting of (1) compositions consisting essentially of aqueous solutions of 2- aminoethanol and alkali-metal salts of Z-mercaptobenzothiazole in amounts conforming to ratios between 35 and 60 parts by weight of Z-aminoethanol to between 65 and 40 parts by weight (based on its Z-mercaptobenzothiazole equivalent) of the alkali-metal salt of 2-niercaptobenzothiazole, and (2) compositions consisting essentially of aqueous solutions of Z-aminoethanol and alkali-metal salts of Z-mercaptobenzothiazole in amounts conforming to those specified in the foregoing composition (1), together with a component of the group consisting of (a) watersoluble salts of cyanodithioimidocarbonic acid, (b) watersoluble salts of cyanodithioimidocarbonic acid and a dlaminoalkane having not more than six carbon atoms in which the amino substituent radicals are on adjacent carbon atoms, the molecular ratio of the diaminoalkane to cyanodithioimidocarbonate in the composition being not more than 1.5, (c) water-soluble salts of cyanodithioimidocarbonic acid, a diaminoalkane having not more than six carbon atoms in which the amino substituent radicals are on adjacent carbon atoms, the molecular ratio of the diaminoalkane to cyanodithioimidocarbonate in the composition being not more than 1.5, and water-soluble salts of N-monoalkyl-substituted dithiocarbamic acids, the alkyl radicals of which have fewer than four carbon atoms, and (d) water-soluble salts of N-monoalkyl-substituted dithiocarbamic acids, the alkyl radicals of which have fewer than four carbon atoms.

3. A composition consisting essentially of an aqueous solution containing 2-aminoethanol and an alkali-metal salt of 2-mercaptobenzothiazole in amounts conforming to ratios between 35 and 60 parts by weight of 2-aminoethanol to between 65 and 40 parts by weight (based on its 2-mercaptobenzothiazole equivalent) of the alkalimetal salt of 2-mercaptobenzothiazole.

4. A composition consisting essentially of an aqueous solution containing equal parts by weight of 2-amino- 10 ethanol and an alkali-metal salt of 2-me1captobenzothiazole (based on its Z-mercaptobenzothiazole equivalent).

5. A composition consisting essentially of an aqueous solution of 2-arninoethanol, an alkali-metal salt of 2-mercaptobenzothiazole, a water-soluble salt of cyanodithioimidocarbonic acid, and a diaminoalkane having not more than six carbon atoms in which the amino substituent radicals are on adjacent carbon atoms, the molecular ratio of the diaminoal-kane to the cyanodithioimidocarbonate in the composition being not more than 1.5 and the amounts of the 2-arninoethanol and alkali-metal salt of Z-mercaptobenzothiazole conforming to a ratio between 35 and 60 parts by weight to between 65 and 40 parts by weight (based on its 2-mercaptobenzothiazole equivalent) of the alkali-metal salt of Z-mercaptobenzothiazole.

6. A composition consisting essentially of an aqueous solution of 2-aminoethanol, an alkali-metal salt of 2-mercaptobenzothiazole, a water-soluble salt of cyanodithio imidocarbonic acid, a diaminoalkane having not more than six carbon atoms in which the amino substituent radicals are on adjacent carbon atoms, and a water-soluble salt of an N-monoalkyl-substituted ditniocarbamic acid, the alkyl radical of which has fewer than four carbon atoms, the molecular ratio of the diaminoalkane to the cyanodithioimidocarbonate in the composition being not more than 1.5, and the amounts of the 2-aminoethanol and alkalimetal salt of Z-mercaptobenzothiazole conforming to a ratio between 35 and 60 parts by weight to between 65 and 40 parts by weight (based on its Z-mercaptobenzothiazole equivalent) of the alkali-metal salt of Z-mercaptobenzothiazole.

7. A composition consisting essentially of an aqueous solution containing the following substances in proportions proximating the following percentages by weight: disodium cyanodithioimidocarbonate 9.4, ethylenediamine 3.5, potassium N-methyldithiocarbamate 12.9, sodium 2-mercaptobenzothiazole 13.8, and 2-aminoethanol 12.2.

8. A composition consisting essentially of an aqueous solution containing the following substances in proportions proximating the following percentages by weight: disodium cyanodithioimidocarbonate 10.1, ethylenediamine 3.7, potassium N-methyldithiocarbamate 13.8, sodiun 2-mercaptobenzothiazole 14.7, and 2-aminoethanol 13.

9. In a process for the production of paper in which an aqueous fluid containing cellulosic pulp and other papermaking ingredients is circulated in contact with a Fourdrinier wire cloth composed of strands of coppercontaining alloys that are normally subject to mechanical wear, the method of increasing the useful life of such wire which comprises adding to aqueous fluids with which the said wire cloth comes into contact, 2-aminoethanol and an alkali-metal salt of 2-mercaptobenzothiazole in amounts conforming to ratios between 35 and 60 parts by weight of Z-aminoethanol to between 65 and 40 parts by weight (based on its Z-mercaptobenzothiazole equivalent) of an alkali-metal salt of Z-mercaptobenzothiazole and at such rate as to provide a concentration of the said two compounds of at least 0.5 part per million by weight of the aqueous fluids in the ratio set forth above in said system.

10. A process comprising adding to the aqueous fluids of a papermaking machine system that includes a Fourdrmier wire cloth the strands of which are composed of copper-containing alloys a mixture containing 2-amino ethanol and an alkali-metal salt of 2mercaptobenzothiazole in amounts conforming to ratios between 35 and 60 parts by weight of Z-aminoethanol to between 65 and 40 parts by weight (based on its Z-mercaptobenzothiazole equivalent) of the alkali-metal salt of Z-mercaptobenzothiazole, at a rate such as to provide a concentration of the components of the mixture of at least 0.5 part per million by weight of the aqueous fluids in the ratio set forth above in the said system.

11. A process for the treatment of a Fourdrinier Wire cloth composed of copper-containing alloy strands which comprises contacting the said cloth with an aqueous solution containing at least 40 parts per million by weight of a mixture of Z-arninoethanol and an alkali-metal salt of Z-mercaptobenzothiazole in amounts conforming to ratios between 35 and 60 parts by Weight of Z-aminoethanol to between 65 and 40 parts by weight (based on its Z-mercaptobenzothiazole equivalent) of the alkalimetal salt of Z-mercaptobenzothiazole.

12. A Fourdrinier wire cloth formed of strands of copper-containing alloy wires carrying a film containing Z-mercaptobenzothiazole and Z-aminoethanol.

References Cited in the file of this patent UNITED STATES PATENTS Ubbelohcle Oct. 15, Brooks Ian. 15, Bustin Dec. 25, Hatch June 21, Andel Oct. 3, Hopkins Nov. 14,

OTHER REFERENCES Some Corrosion Inhibitors, from Corrosion, vol. 11, No. 4, pages 65, 66 and 67, April 1955, 212.7.

Claims (1)

12. A FOURDRINIER WIRE CLOTH FORMED OF STRANDS OF COPPER-CONTAINING ALLOY WIRES CARRYING A FILM CONTAINING 2-MERCAPTOBENZOTHIAZOLE AND 2-AMINOETHANOL.