US2905583A - Decorative felted fibrous sheet - Google Patents

Description

United States Patent DECORATIVE FELTED FIBROUS SHEET David A. Feigl In, Lancaster Township, Lancaster County, and oyd V. Hassel, East Hempfield Township, Lancaster County, Pa., asslgnors to Armstrong ctlllk Company, Lancaster, Pa., a corporation of Pennsy vanla No Drawing. Application May 2, 1955 Serial No. 505,522

25 Claims. (Cl. 162-134) This invention relates generally to beater saturated fibrous sheets, and more particularly to beater saturated felted fibrous sheets made from compositions containing synthetic elastomers. Still more particularly it relates to a method of producing a decorative pattern in sheets which have been beater saturated with synthetic elastomers. It also relates to products so produced.

The known beater saturation technics have yielded many excellent fibrous sheets. Yet if any one property has characterized sheets formed by means of the beater saturation processes, it has been homogeneity. All such sheets are outstanding in that a sheet presents a homogeneous appearance. This is true because the very purpose of the beater saturation processes is to produce homogeneous sheets. The goal is to symmetrically and evenly coat the individual fibers and then form the coated individual fibers into a sheet. Thus a sheet made in a heater saturation process does not present a distinctive, easily discernible, attractive pattern.

It is the primary object of the present invention to present such a sheet. It is a further object of the present invention to present a sheet made by the beater saturation process which possesses sufliciently attractive appearance to be utilized as a surface covering without the need for any further steps involving the application of decorative designs or patterns. Further objects and advantages will become apparent from the ensuing description.

Accordingly, the present invention contemplates forming an aqueous slurry containing sheet-making fibers. There is added to the slurry a tacky synthetic rubber in amounts sufiicient to form coated fibers of at least about 30% by weight of the rubber. The coated fibers are then formed into clumps in a first suspension. The first suspension is then admixed with a second suspension of coated fibers having a color difierent from that of the first suspension. The resulting mixture is then formed into a sheet.

The fibers contemplated for use in the present invention may be any of those fibers known to be useful in the beater saturation process. Glass fibers, bleached semichemical pulp, purified cotton linters, raw cotton linters, kraft fibers, wool, goat hair, rayon, nylon, and other similar fibers may be used. The selected fiber is formed into an aqueous slurry in accordance with known beater saturation technics. Usually the fibers will comprise from about 0.5% to about 5% by weight of the slu l ii order that the amount of rubber latex to be deposited on the fibers may be controlled, the fibers may be pretreated prior to rubber addition by adding an electrolyte in the form of a salt of aluminum, ferric iron, stannic tin, or other polyvalent metal. The electrolyte may be added in the form of a solid or as an aqueous solution. Examples of suitable electrolytes are alum, aluminum chloride, aluminum sulfate, magnesium chloride, magnesium sulfate, ferric chloride, ferric sulfate, stannic chloride, and stannic sulfate. Once the electrolyte has been Patented Sept. 22, 1959 dissolved, a suitable soluble hydroxide is added in order to convert the metal ions to an insoluble state. Sodium hydroxide or ammonium hydroxide are the preferred hydroxides to be utilized. The insoluble hydroxide serves to control the deposition of the rubber latex on the fiber coated with or containing the metal hydroxide.

This use of an electrolyte and a hydroxide to control deposition of rubber latices is known in the art as the Pretzel process. Generally speaking, however, the amount of electrolyte to be added in the usual process will range from about 33 to about 60 parts by weight per 100 parts by weight of dry latex solids. This amount is essential in order that the latex will deposit smoothly onto the fibers and in order that it will not clump with itself or cause the clumping of fibers. In the process of the present invention, however, a smaller amount of electrolyte is added in order that the usually detrimental clumping may be forced to take place. Thus it can be seen that the process of the present invention is opposed to the usual beater saturation process in that it turns a normally detrimental situation into an advantage. Generally speaking, the amount of electrolyte to be utilized in the present invention as described will range from about 5 parts by weight to about 15 parts by weight per 100 parts by weight of dry latex solids. Different fibers and ditferent latices will cause some variation within the above range in the amount of electrolyte to be used in the present invention. However, with any given system, forming of the clumps calls for substantially less electrolyte than that needed for the same system in normal beater saturation processes. Usually the amount will be one-third to onehalf that normally used. Since this amount is usually not sufiicient to complete the precipitation, a precipitating solution of alum sequestered with sodium citrate or its equivalent may be used to complete the process once the rubber has been added; this precipitating solution constitutes an aftertreatment made once the rubber has been added.

Following the solution of the electrolyte in the fibercontaining slurry, the hydroxide, preferably ammonium hydroxide, will be added as described above. The amount of hydroxide will be that equivalent to the metal ions added as the electrolyte, with a slight excess; this is obvious since the aim is to convert all the metallic ions to the insoluble hydroxide. Since the amount of electrolyte is substantially less than the amount normally used, it can be seen that the amount of hydroxide also will be correspondingly less than the amount normally used. Once the insoluble hydroxide has been formed, tacky synthetic rubber is added to the slurry, preferably as a latex. Since it is essential in the present invention that the coated fibers be formed into clumps, an amount of the rubber latex must be added which will accomplish the necessary clumping. It has been found that clumping will occur only when at least about 30% by weight of the coated fibers is made up of the tacky synthetic rubber. Thus the pick-up must be about 30% by weight based on the dry weight of the fibers. Although clumping will occur to some extent when the pick-up is at least about 30%, higher pick-ups are preferred. The pattern elfect achieved by the present invention is noticeable at 30% pick-up but it becomes outstanding at about 50% pick-up. Thus it is a preferred embodiment of the present invention that the coated fibers contain at least about 50% by weight of the rubber.

The rubber to be used in this invention may be any of a number of those tacky synthetic rubbers well-known in the art. Typical of these materials are the products known as GR-S, which is a copolymer of butadiene and styrene containing about 50% to 70% butadiene; Hycar," which is a copolymer of butadiene and acrylonitrile containing about 60% to butadiene; and certain of the neoprenes, which are polymers of 2-chloro-butadiene- 1.3. If desired, homopolymers of butadiene may be employed as well as homopolymers and/or copolymers of butadiene homologues such as isoprene. These materials can be generically described as synthetic rubber, and in particular they must possess the property known as tackiness. Since those synthetic products containing less than about 50% by weight butadiene are generally not tacky, these latter materials are generally unsuitable in the present process.

Once the rubber latex has been added to the slurry, the fibers should be formed into clumps. It is this portion of the present process that particularly violates normal beater saturation technics. Where the proper amount of electrolyte has been used and where the proper quantity of rubber latex has been added as described above, clumps will readily form on agitation. Where the amount of rubber deposited on the fibers is near the lower limit necessary to form clumps, namely about 30% pick-up, agitation must not be unduly prolonged in order that the formed clumps may not be disrupted. Where, however, the amount of rubber deposited on the fibers is of the preferred amount, namely 50% and up, it will be found that the clumps are surprisingly strong and can withstand a great deal of beating without being disrupted.

The above description has dealt with the forming of clump fibers solely by the use of a pretreatment involving an electrolyte and hydroxide addition. Alternatively, the electrolyte treatment may be omitted and instead a precipitating solution may be added subsequent to the rubber addition even in the absence of an electrolyte addition. The precipitaing solution may consist of acetic acid alone or a solution of alum alone or a solution of alum. citric acid, or sodium citrate in water. The precipitating solution containing a precipitating agent is added in amounts sufficient to preci itate the rubber on the fibers and to form clumps. The precise amount of precipitating solution will depend on the type of fibers and on the amount of rubber being used in any particular case. If desired, use of the acidic precipitating solution may be coupled with the use of an electrolvte to obtain more precise control over the clumping of fibers. Thus, in the present invention clumps may be formed by pretreatment of the fibers with an electrolyte. by aftertreatment of the latex with a precipiating solution, or by various modifications involving both treatments.

Once the first suspension of clump fibers has been formed. the next ste entails admixing the above-described first suspension with a second suspension of fibers having a color different from that of the first suspension. This color difference may be accomplished in several ways. A dyestutf or pigment may be incorporated into the slurry of the first suspension before clumping, or the dye or pigment may be incorporated into the slurry of coated fibers prepared by normal homogeneous beater saturation processes. if desired, a series of suspensions each containing clumped fibers may be prepared wherein each suspension possesses a different color. The clumped suspension may then be mixed prior to sheet formation. In similar manner, 1, 2, or more clumped suspensions may be admixed with a non-clumped suspension of fibers coated in the usual way; the colors of the different suspensions may be adimted as desired. To put it another way, at least one suspension of clumped fibers is admixed with at least one other suspension of clumped or unclumped fibers wherein at least two of the mixed suspensions possess different colors.

The final step in the process is the forming of the resultant mixtnre into a sheet. The sheet is formed in a conventional way by feeding the mixture to any paper-forming machine, such as a Fourdrinier, cylinder machine, wet machine, or the like, for felting into fibrous sheets.

It can be seen that a sheet made by the present process will possess interesting decorative pattern or design effects.

There will always be a color contrast between at least one portion of the sheet resulting from clumped fibers and at least a portion of the balance of the fiber: in the sheet. It should be apparent that sheets possessing as many colors as desired may be prepared. Contrasting colors may be selected to achieve a predetermined effect on the viewer and as many colors may be selected as desired. Additionally, the size of the clumps may be controlled to some extent both by controlling the amount of latex used and also the amount of electrolyte used in pretreatment. This allows to some degree the selection not only of the colors, but of the size of the color splashes that will appear in the final sheet.

Once the sheet has been formed on the conventional papermaking equipment, it need only be dried to be useful in certain applications as in wall coverings. Drying may be accomplished at room temperature or at elevated temperature in a suitable oven or stove, under a radiant heater, or on the conventional drum driers of a papermaking machine.

The product, however, maybe further treated in order to broaden its uses. For example, if a floor covering material is desired, the density and resistance of the product may be increased by subjecting it to pressure, preferably at elevated temperatures. Should a long-wearing floor covering be desired, a final facing, clear or colored, may be laid over the sheet of the present invention to serve as a wear surface. Such a film, preferably of a vinyl polymer, may be hot pressed onto a surface of a sheet of the present invention, or it may be doctored or rolled on in the form of a liquid and subsequently cured at elevated temperature. The entire sheet may be cured with or without pressure.

If desired, the pattern sheet of the present invention may be impregnated with a thermosetting resin and then cured at elevated temperatures under pressure to form an attractive surface covering useful in covering desks, counters, tables, and the like. It can readily be seen that such a product will be highly resistant to water, alkali, acid, and the normal hazards of such applications, for example cigarette burns. At the same time, the product preserves the pattern appearance built into it by the beater saturation process.

The sheet formed by the present invention may also serve as a base upon which to print a wear-resistant decorative paint coat in accordance with known procedures, using the built-in pattern as background. Even if the built-in pattern is completely covered, the undersurface will preserve its recorative appearance, and the appearance may thus serve as a kind of trade-mark to identify the particular composition used or to distinguish between surface coverings whose wear surfaces present similar appearances.

The following examples illustrate various embodiments of the present invention. All parts listed are by weight unless otherwise stated.

Example I Three sheets were prepared from the above three slurrles, each sheet containing different amounts of the difierfent clumped fibers, namely, one-third red, one-third green; and 45% green; and 213696 green.

1) one-third black, (2) 10% black, 45% red, (3) 56%% black, 21%% red, and

Example II Three slurries were prepared using the following ingredients and amounts:

lbergias Primuline Yellow- Bleached semiehemicai pulp Pontamine Scarlet" Purified cotton linters. Pontamine Grnen"- Alum, solution Ammonium hydroxide, 28% solution.. GR-S N0. 2000, 38 o Alum-Citrate precipitating solution...

The precipitating solution was added after the rubber. It consisted of 50 parts water, 5 parts alum, and 3 parts sodium citrate.

Three sheets were prepared, each containing an equal mixture of one-third of the total weight of each of the slurries described above. Each of the 12" square sheets prepared as in Example I was subjected to 300 pounds wet pressure.

Each sheet was saturated with a solution of Melmac 405" (thermosetting melamine-formaldehyde resin) dissolved in a 50-50 mixture of water and denatured alcohol. The percent pick-up for each of the three sheets varied between 31 and 51.5%.

Subsequent to the "Melmac 405" treatment, each sheet was maintained under a pressure of 600 pounds per square inch at a temperature of 305 F. for a period of 10 minutes.

There resulted hard thin sheets having an acid and alkali resistant surface, excellent tensile strength, and flexibility, while at the same time possessing an attractive mottled appearance of three colors.

Example III Two slurries using the following ingredients in the amounts listed were prepared:

In each case the (SR-8 was precipitated by the addition of a precipitating solution made up of 50 parts water, 5 parts alum, and 3 parts sodium citrate.

Sheets were made up containing equal parts of the above two very clumpy slurries. Three sheets were prepared-one in which there was a minimum of stirring, one in which the two slurries were combined and then stirred together for 5 minutes, and a third sheet in which the slurries were stirred separately for 5 minutes and then combined.

The three sheets all exhibited very similar appearances, thus showing that the clumped fibers maintained the clumps even under vigorous agitating conditions. The three sheets were dried in an oven at 195 F. Similarly, three other sheets prepared as above were dried on a drum drier having a surface temperature of 230' F.

Tough attractive sheets suitable for surface covering resulted in each case.

Example IV A clumped slurry of refined cotton linters containing 50% 611-8 based on the dry weight of the fibers was pre pared as in Example Ill, save the dye was omitted.

40 parts of raw cotton linters was combined with 0.3 part Pontamine Green BXN," 5 parts Sorapon SF" (a sodium alkylarylsulfonate wetting agent), 5 parts dry alum, followed by 2.6 parts ammonium hydroxide.

The undyed clumped refined cotton linters were mixed half and half with the dispersed and uncoated raw cotton linters, dyed green, prepared as above.

On drying, an excellent mottled sheet resulted.

Example V Two slurries were prepared using the following ingredients and amounts:

Ingredients No. 1 No, 2

Water 4, 000 4, 000 Refined cotton linters. 40 Raw cotton linters 40 Pontnmlne Green BXN 0. 3 Alum l 6. 0 Sodium citrate l gg,s

amo .0 on-s III (mimi with 'lamol N) 7s. 0

weight of fiber) Example VI Two slurries were prepared having the following ingredients:

Ingredients No. 1 No. 2

Water 12, 000 12, 000 Refined cotton iinters 120 Pontamlne Green EX 0. 9 Alum (dry) 6.0 0. 0 Ammonia.--- 3.0 3.0 "Hyoar 1501" (40% solids) 150.2 1150. 2

In each case precipitation was done by a solution of 50 parts water, 5 parts alum, and 3 parts sodium citrate.

Sheets formed from half and half mixtures of the above two clumped slurries were strong and attractive in appearance.

Example VII Two slurries were made having the following ingredients:

Ingredients No. 1 N o. 2

Water 12,000 12, 000 Refined cotton linters. 120 120 Pontamlne Green BXN" 0. 9 Alum 0. 0 6.0 Ammonia 3. 0 3.0 Neoprene (36%) l7l. 0 17!. 0

The neoprene was precipitated with a solution of 50 parts water, 5 parts alum, and 3 parts sodium citrate.

Sheets formed from half and half mixtures of the two slurries were strong and possessed an attractive mottled appearance.

We claim:

l. The method of producing a decorative pattern m beater saturated fibrous sheets which comprises forming an aqueous slurry containing sheet-making fibers, adding to said slurry sufficient tacky synthetic rubber to produce coated fibers of at least about 30% by weight of said rubber, forming clumps of said coated fibers in a first suspension, admixing said first suspension with a second suspension of fibers having a color ditferent from that of said first suspension, and forming the resulting mixture into a sheet.

2. The method of producing a decorative pattern in beater saturated fibrous sheets which comprises forming an aqueous slurry containing sheet-making fibers, adding to said slurry sufficient tacky synthetic rubber to produce coated fibers of at least 30% by weight of said rubber, adding to the resulting slurry an acidic precipitating solution to form clumps of coated fibers in a first suspension, admixing said first suspension with a second suspension of fibers having a color different from that of said first suspension, and forming the resulting mixture into a sheet.

3. The method according to claim 2 wherein said precipitating solution comprises alum and sodium citrate.

4. The method according to claim 2 wherein said rubber comprises a butadiene-styrene copolymer containing at least about 50% butadiene.

5. The method of producing a decorative pattern in beater saturated fibrous sheets which comprises forming an aqueous slurry containing sheet-making fibers, adding a water-soluble, polyvalent-metal, electrolyte salt to said slurry, converting said electrolyte to a water-insoluble hydroxide by reacting the same with a hydroxide, adding to the resulting slurry a tacky synthetic rubber in an amount sutficient to form coated fibers of at least 30% by weight of said rubber, adding a precipitating solution to the resulting slurry to form clumps of coated fibers in a first suspension, admixing said first suspension with a second suspension of fibers having a color difi'erent from that of said first suspension, and forming the resulting mixture into a sheet.

6. The method according to claim 5 wherein said electrolyte salt is alum.

7. The method according to claim 5 wherein said rubber comprises a butadiene-styrene copolymer containing at least about 50% butadiene.

8. The method of producing a decorative pattern in beater saturated fibrous sheets which comprises forming an aqueous slurry containing sheet-making fibers, adding a water-soluble, poIyvalent-metal, electrolyte salt to said slurry in that amount sufficient to cause clumping of the fibers when coated with a rubber, converting said salt to a water-insoluble hydroxide by reacting the same with a hydroxide, adding to the resulting slurry a tacky synthetic rubber in amount sufiicient to form coated fibers of at least 30% by weight of said rubber, forming the coated fibers into clumps in a first suspension, admixing said first suspension with a second suspenion of coated fibers having a color different from that of said first suspension, and forming the resulting mixture into a sheet.

9. The method according to claim 8 wherein said tacky synthetic rubber comprises a butadiene-styrene copolymer containing at least about 50% butadiene.

10. The method according to claim 8 wherein said second suspension comprises clumped coated fibers.

11. The method according to claim 8 wherein said water-soluble salt comprises alum.

12. The method according to claim 8 wherein said coated fibers comprise at least 50% by weight of said tacky synthetic rubber.

13. The method according to claim 8 wherein said sheet-making fibers comprise cotton linters.

14. The method of producing a decorative pattern in beater saturated fibrous sheets which comprises forming an aqueous slurry of cotton linters, adding alum to said slurrry in an amount only suflicient to cause clumping of the fibers when coated with a rubber, converting the alum to a water-insoluble hydroxide by reacting the same with ammonium hydroxide, adding to the resulting slurry a latex of a butadiene-styrene copolymer containing at least about 50% butadiene in amounts sufiicient to form coated fibers of at least 30% by weight of said copolymer, forming the coated fibers into clumps in a first suspension, admixing said first suspension with a second suspension of coated fibers having a color different from that of said first suspension, and forming the resulting mixture into a sheet.

15. The method according to claim 14 wherein said second suspension comprises clumped coated fibers.

16. The method of producing a decorative pattern in beater saturated fibrous sheets which comprises forming an aqueous slurry containing sheet-making fibers, adding alum to said slurry in an amount of about 1-6 parts by weight per parts by weight butadiene-styrene solids subsequently added, adding sufiicient ammonium hydroxide to said slurry to convert said alum to an insoluble hydroxide, adding to the resulting slurry a latex of a butadiene-styrene copolymer containing at least about 50% butadiene in amounts sufiicient to form coated fibers of at least 30% by weight of said copolymer, forming the coated fibers into clumps in a first suspension, admixing said first suspension with a second suspension of coated fibers having a color difierent from that of said first suspension and forming the resulting mixture into a sheet.

17. The method of producing a decorative pattern in beater saturated fiber sheets which comprises forming an aqueous slurry containing sheet-making fibers, adding to said slurry sufiicient tacky synthetic rubber to produce coated fibers of at least about 30% by weight of said rubber, forming clumps of said coated fibers in a first suspension, admixing said first suspension with a second suspension of fibers having a color difierent from that of said first suspension, forming the resulting mixture into a sheet, impregnating said sheet with a curable resin, and curing said resin at an elevated temperature.

18. The method according to claim 17 wherein said resin comprises a melamine-formaldehyde resin.

19. The method of producing a decorative pattern in beater saturated fiber sheets which comprises forming an aqueous slurry containing sheet-making fibers, adding to said slurry sufiicieut tacky synthetic rubber to produce coated fibers of at least about 30% by weight of said rubber, forming clumps of said coated fibers in a first suspension, admixing said first suspension with a second suspension of fibers having a color difierent from that of said first suspension, forming the resulting mixture into a sheet, coating said sheet with a curable synthetic resin, and curing said synthetic resin at elevated temperature to form a wear-resistant layer on said sheet.

20. The method according to claim 19 wherein said curable synthetic resin comprises polyvinyl chloride.

21. A decorative felted fibrous sheet comprising clumps of coated fibers coated with at least about 30% by weight synthetic rubber, said clumps having a color different sfi'lom at least a portion of the balance of the fibers in said eet.

22. A decorative felted fibrous sheet comprising clumps of coated fibers coated with at least about 30% by weight synethetic rubber, caid clumps having a color different from the balance of the fibers in said sheet.

23. A decorative felted fibrous sheet comprising varicolored clumps of coated fibers coated with at least about 30% by weight synthetic rubber.

24. A decorative felted fibrous sheet comprising clumps of coated fibers coated with at least about 30% by weight synthetic rubber, said clumps having a color dificrent from at least a portion of the balance of the fibers in said sheet, said sheet being impregnated with a cured synthetic resin.

25. A decorative felted fibrous sheet comprising clumps References Cited in the file of this patent UNITED STATES PATENTS 2,322,887 Schwartz June 29, 1943 2,375,245 Pretzel May 8, 1945 2,474,801 Owen June 28, 1949 2,613,190 Feigley Oct, 7, 1952 2,635,045 Bixler et a1 Apr. 14, 1953 10 Horsey et al. Aug. 25, 1953 McQuiston Jan. 19, 1954 Kao Apr. 20, 1954 Yundt Apr. 12, 1955 Hatcher Aug. 9, 195,5 Feigley Aug. 9, 1955 Baymillcr Oct. 11, 1955 OTHER REFERENCES Technical Association of Pulp and Paper Industry Journal (TAPPI), vol. 34, No. 1, January 1951, p. 46.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2,905,583 September 22, 1959 David A. Feigley, Jr., et al It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 4, line 4'7, for "recorative" read decorative line '72, for "differfent" read different column 5 line 57, in the table, third column thereof, last item, for "158.0" read 158.l column 8, line 64, for "synethetic" read synthetic same line 64, for "caid" read said Signed and sealed this 5th day of April 1960.

(SEAL) Attest:

KARL H. AXLINE ROBERT C. WATSON Commissioner of Patents Attesting Officer

Claims (1)

1. 8. THE METHOD OF PRODUCING A DECORATIVE PATTERN IN BEATER SATURATED FIBROUS SHEETS COMPRISES FORMING AN AQUEOUS SLURRY CONTAINING SHEET-MAKING FIBERS, ADDING A WATER-SOLUBLE, POLYVALENT-METAL, ELECTROLYTE SALT TO SAID SLURRY IN THAT AMOUNT SUFFICIENT TO CAUSE CLUMPING OF THE FIBERS WHEN COATED WITH A RUBBER, CONVERTING SAID SALT TO A WATER-INSOLUBLE HYDROXIDE BY REACTING THE SAME WITH A HYDROXIDE, ADDING TO THE RESULTING SLURRY A TACKY SYNTHETIC RUBBER IN AMOUNT SUFFICIENT TO FORM COATED FIBERS OF AT LEAST 30% BY WEIGHT OF SAID RUBBER, FORMING THE COATED FIBERS INTO CLUMPS IN A FIRST SUSPENSION, ADMIXING SAID FIRST SUSPENSION WITH A SECOND SUSPENSION OF COATED FIBERS HAVING A COLOR DIFFERENT FROM THAT OF SAID FIRST SUSPENSION, AND FORMING THE RESULTANT MIXTURE INTO A SHEET.