[1]United States Patent Office 321949856 39194,856 Pill-FTI-IOD OF PRODUCING DECORATIVE SURFACE COVERF-I\TG Leon B. Palmer, L!ttle Falls, N.J., a,@signor to Co ngolei-,--nNairn Inc., Kearny, N.J., a co-rporation of New YoriK Filed Apr. 17, 1961, Ser. No. 103,590 The portion of tire term of tiie patent subsequeint to .Tune 6, 197'ol, has been discwpiied and dedicated to the PL@blic 5 Clairqs. (Cl. 264-76) This Liverxtion relates to I;noicum useful as a surfece cov--ring for floors, walls and the like and in parlicular to a method of creati-@ig no@i-directional decorative effects in a Iiiiole,,iw@ surface covering. This application is a contintiation-in-part of application Serial No. 705,653, --'iled Dece,- iiber 27, 1957, now aba,@idor,ed. Linoietim is a well-know@i resilient surfacp- covering which has been used i.Or alriost 100 years as a covering for floors, walls, articles of furniture and the like. Basically, the ingredients used in the production of linoJeL,m today are s;milar to those in use when it was first d,'@scovered aild, in general, comprise okidized drying oils, resi@-is, pigir-ents ard fillers. In the@ production of linoleum, a blord of these in.-redients is sheeted by any one of a iiuir.ber of sheet-forming techniques, such ascale-@ideiing and pressing. The coniposition sheet is bonded to a backing and f@r@ally is subjected to heat for extended periods of tii@-e to effect cure of the coir-position. Linolev m surface coverings are recognized as having lot.,g life an-d d-arability, goodflexibility aid resilier@ce, as we'@l as r,-s@,@stance to acids, alkalies ind other soiliig agents. After t@e discovery of linoicur@i, it was initially prc)e,i-iced primarily in the form of plain color-.d slacets. Alt-hou,@h products of this type are manufacttired today, they have been largely displaced by products with rpore i-@itricate and appealing decorations. It was found a-t an early date that, if particles of colored linoleum composit-'!on were uniformly distriblited ;n a mass of linoleum con,.position having a contrast-@'ng color, ar@d then the resultin.- mass sheeted between calender rolls, attractive prodiicts could be produc,-d. Durilig cale@-.dering, the colored particles become distorted ar@d s@meared to y@'eld loi,g, colored streaks in the pro-@luct. TMs ef-fect is well I-,no,i;,n in ti@e art as iaspe. Jaspe Iiiiolouin prodrcts are attractive and comparitively low ii cost, but have '@he d'sadva.ita,@e that the d,,corat@"ve streaks penetrate 0-@1117 a s-mall p--rcentige of the thickness of the product. Tlus, the decor,-,tion of the jaspe linoleii-m changes dliring wear after the proluct is install.-d. The colored streaks boconie cut and broken arid, in soine cases, disappear altogeth--r. Since the above deserbed decorative effects are characte.-ized by having long streaks of color the decoration has a pronounced directional characteristic. This effect is desirable iii certa@'.n types of iiistallations but there ar-areas and decorating schemes where a non-directional decor@,tive effect is particularly desirable. A non-dircetional decorative of-Fect e-fiti be produced by the techniatic known as geometric inlaid. In this method, sections of the desired shace are cut fro--.p the linole-Lirn base sheet and 'Lhe o!),-ni@i-,,s so formed are filled with olitouts taken from she@ts of coillrasting colors. The resulting cciriposit,- sh,-et -s calendered to ftise the corr@ponents togetlier. The decora'@ive cittot,.ts can take iny desired georfetrical Paf-enf.e-J July 13, 19-05 f-,riii z,.r@d ii-,Us the, fl-riished product can have a nondirec',io-iial type of decoration, Siic.- the decorative cutoljts exte-.id the full ihick-riess of the base @ii.- et, it is appare-nt that 1: leum so prcduced has the desirable property :@hat the decoration remains unchanged durin.- wear. -How-.ver, sleh products are expensive to prc-duce. The equipme-Tit needed for producing -eometric linoleum in commerc;al qupntities reorese-@its the investr@ient of several hu@ndrr-.d @hoLisand dollars. In addition, in some patterns 10 the cuto,,i-s @to be -Dlaced ;Ti th.- openings formed in the base sheet can represer@t as little as 10 percent of the tofal area of th@- sheet. TPe remainin.- 90 percent of the sheet used -.n foriring tli-- cutolqs must be chopped up and rcsriected. Th;s large percentage of reprocessing 1,5 adds materially to the cost of producing such products. A further disadvanta.-e ol. this tec-hnique is that, for each geometr,'@c efi-,ct desired, expensive cutting cylinders ar@d dies must be prodliced. A popular type of ron-directional decoration which 20 is widely used in resilient floor coverings simulates terrazzo. Another type of nondirectional decoration wbich has been created in linoleuni siniulates the appearance of a spattor dec.ign floor. This @type of decoration was originally created by spatter,.ng a plurality of different 25 colored paint compositions over a base paint color v,,hich had previoiisly b-,en applicd to the floor. Both terrazzo and spptt.-r desi.-n effects have been created in resilient i'loor coverin(,,s by depositing colored granular compositio-@i through carefully cut a-nd ali,-ned stencils upon a back3o ing followed by consol-idating the conposition by molding in a ilat bed press. The sheet can also be subsequently er@ibossed to produce a two-level product. Although this ricthod does create !he desired non-directional effect, 't has sigiii@Icant disadirg@nta-es. First, the stencils must 30- be carel@@Ully aligned over the base sheet so that the differeiit colored compositions will fall in exactly th,- proper location on the back which is normally saturated felt. 11 'ihere is any misalignment of the stencils, areas of the backing rel--qain tincovered by coinposition with the result 40 that an unsatisfactory product is produced. Secopd, there is conventionally a sepirate stencil for each of the colors desired in the finished product. Thus, considerable manpower is required since individual batches of coinposition must be suppl;ed to each stencil. Third the use of a 45 i'lat bed press results in a slow discontinu@.s operation with the resi-ilt that processing costs are high. It would be hi.-lily desirable to be able to create such i-on-directional decorative citects in linoletim using conver-tioiial calenderiiig and finishin.- equiprnent in a con5o iiiiuous operation. Heretofore, ittempts to do this have b@-en ulisticeessfiil. The @depositii-ig of linoleum compositio.@i iri the form of decorative chips upon a lir@aleum composi@ion base sheet followed by passin-. to the iiip bet@,ve-.n caler@dcr rolls has invariably resulted in distortion 55 and smearin.- of tlc decorative composition. The result is a product which has a highly directional appearance similar to t-'qe v/ell known jaspe decorations of the prior art. In additio-,i, attenipts 1,0 embed linoleum composition into a linoleum composition base sheet result in 60 teir;iig of the sheet due to strains which develop during the calendering process. These strains develop due to niir.,,,ite di,@Ter--nces in the spacing between the calender ro',Is across the width bf t'le sheet being calendered. It has been found virtually in-@possible to correct these minor 65 diff-erences i-.i roll spaciiig t,irough grindiig of the roll
[2]surfaces. Even if a uniform ro'@l -spacing could be obtained, uneven wear of the roll surf ac,-s would soon result in differences in spacing. Attempts to alleviate this problem by directly calendering a mass of grqnular material onto a saturated felt backing have also failed. The hard, relatively unyielding nature of the backing in comparison to the consistency of the linoletim cornposition results in extreme lateral spreading of th-. composition as it passes between the calender rolls. The result is a product having marked directional characteristics due to the distortion of the decoration, It is an object of the invention to produce a nondirectional decorative effect in linoleum in a continuous process. It is a further object of the invention to produce a nondirectional decoration in linoleum by calenderi@i-, granular linoleum composition without stibstant,"al di--tortion of the decoration developing. It is anotti,-r object of the invention to provide a method of calendering granular linolcurii composition onto a linoleum composition base sheet without the development of strains in the sheet during calendering. Other objects ar@d the advantages of the invention will appear hereinafter. In accordance with the invention a decorative linoleumcomposition sheet having a non-d:@rectional decorative effect is produced by depositing upon a linoleum composition base sheet .-ranules of linoleum composition and passing the mass between calender rolls which are spaced apart a distailce gr-,ater than the thickness of the base sheet, thereby forming a decorative sheet having the granules embedded in the surface of the sl-icet without substantial distortion of the granules. The invention will be described wil,h reierence to t@c drawing wherein FIGURE 1 is a schmatic representation of the production of a decorative linoleum composition sheet in accordance with or@e embodiment of the inve-@ition, FIGURE 2 is an enlarged cross-sectional view of the product produced by the method illustrated in FIGURE 1, FIGURE- 3 is a schematic representation of tle production of a decorative linoleum composition sheet in accordance with a second embodiment of the invention, and FIGURE 4 is an enlarged cross-sectional view of the product produced by the method illustrat,-d iri FIGURE 3. With reference to the drawing, a hopper 11 is t'ill,-d with finely divided multicolored I.inolcum composition 12 wwch is sheeted betn@ieen calender rolls 13, 14 to form a base linoleum composition layer 15. The layer is carried from the calender rolls by means of a conveyor belt 16. Finely divided multicolored linoleum composition granules 17 are maintained above the conveyor belt in a feed hopper 18. One side of the feed hopper is formed by a rotating drum, the circunference of Nvhi,.h is provided with a plurality of evenly spaced projections 20 which extend the full width of the drum. The projections form a plurality of spaces 21. The drum is rotated at a uniforni rate removing granules from the hopper in the spaces formed by the projections op the drum. The bottom of the feed hopper is provided with a resili---.lt sealing member 2Z which se.-ves to prevent leakage of granules from the hopper. The granules fall from the side of the drum opposite to that in contact with the hopper i@,non the base sheet carried by the conveyor belt to form a layer of finely divided granular material 23. Decorative piecbs 24 of linoleum composition in th@,form of coarse granular material aremaintainld in a feed hopper 25. The feed hopper is associated wita a rotating drum 26 in the same manner as the hopper 18 is associated with drum 19. The circumference of thO drum is provided with evenly spaced projections 27 which form space 28. A resilent sealing member 29 prevents leakage from the hopper. The pieces fall from the side of the drtim opposite to that in contact with the hopper upon the layer of finely divided granules to lorm pieces 30. The mass is carried by motion of the conveyor belt into the niD formed between calender rolls 31, 32 from which is Temoved a linoleum cor-nposition sheet 33 wbich has a greater thick-ness than that of the base sheet of l@iioleum composition. The sheet passes to a felt laminatinunit formed of a lower roll 34 havin- a resilient cover 35 and an upper roll 37. A sheet 36 of impregnated felt passes over the resilient covered rc)ll and contacts the linoleum cornposition sheet in the ni-D 10 between the two rolls. The product 41 is ready to be stoved in the conventional manner following which it is ready for use as a linoleum surface covering. With reference to FIGURE 2, the product in cross section is made up of the decorative linoleum composi15 tion layer 33 and the felt backing 36. The linoleum sheet 33 is fiiled with interspersed areas of color as shown at 42 which result both from the finely divided linoleum composition 12 used to form the base layer, and also from the fine granular material 17. Some of the fine 20 granular material is embedded into the surface of the sheet 33 as shown as areas 43. The decorative pieces 24 which are deposited upon the fine granules and then embedded into the base layer form areas of color such as those shown at 44 which penetrate deeply into the 25 thickness of the sheet 33. A second embodiment of the invention is shown in FIGURE 3 wherein a product is produced as shown in the cross-section of FIGURE 4 which is similar to th-@ prodlict shown in th-- cross-section 2, except that the o decorative chips are rais-@d sligbtly above the surface of the product so that it has a texttired or embossed appc,,irance. As a general rule in such a product, the chips should not extend above the surface for a distance greater than one-third the thickness of tho chips to insure good ktiit of the product. The chips, therefore, preferably extend abov@- the siirface less than 0.009 inch with about 0.002 to abolit 0.004 inch being preferred. A hopper 11 is filled with finely divided linoleum chips 12 which are fed to calender rolls 13 and 14 and con40 solidated into sheet 15. A felt backi@ig sheet 36 can then be laminated to the - Linderside of the sheet 15 by passing to a felt laminating unit formed of a lower roll 34 havin-, a resilier@t coier 35 and an upper steel roll 37. CWps 50 of linoleum cor.3p6sition are maintained above 4 the sheet 15 in a feed hopper 25. One side of the fe,-d hopper is formed by a rotating drum 26 with a pliirality of evenly spaced projections 27 wbich extend the full width ff. the druni. The projectio@is form a plurality of spaces 23. The drum 26 is rotated at a unif'Orm rate removirig chips 50 from the hopper 25 in the spaces 50 formed by tl-.e projections 27 on the drum. The bottom of th-. feed hopper is provided with a resilient scaling rnember 29 which serves to prevent leakage of chips 50 from th.- hopper 25. The chips 50 fall from the 55 side of the drum 25 opposite to that of the hopper 25 upon the base sheet 15 passing below to form a single layer of chips. The base -sheet 15 cover,-d with the chips 50 ca-@i then, if desired, be passed through a heater generally indicated at 39 such as a bank of infrared lami)s 60 39. The heater serves tO Taise the temperature of the base sb-eet 15 slightly in order to rnake it readily deformable. Tb-e heated sheet is then passed into a finishing unit generally indicated at 60 comprising a larg@drum 61 surrounded by a series of smaller pressure rolls 65 62. A rubber belt 63 passes between the smaller rolls C-2 and the drum 61. The base sheet 15 covered with the decorative chips 50 is passed between the rubber belt and the drum whereby the decorative chips 50 are forced into the base sheet 15. The pressure exerted on 70 the chips is limited so that they are not completely ernbedded in the base but project slightly above the bas-th@.reby producing a textured product. The finished sheet 70 is then ready to be stoved in the conventional iiianner following which it is ready for @-use as a linqleum 110- surface cov,-ring.
[3]Tli-- composition used to form bbth thpdecorative is formed into a sheet between relatively cold cal,-ndar gran,,ilar material and the base layer is any compositioii which is well knoivn in the art as linoleum com@ position. Such a comrosit;on comprises a ble@id of oxidi2fed and partially polymer-lzed drying oils, resins, pi,-ments and fillers. Any of the dryin.- or semi-drying oils vimch are characterized by being oxidized' and polymerized to a hard, tough consi.@ter@ey by the application of heat can be used. Such oils as linsecd oil, soybean oil, Chinawood oil, perilla oil and th-. like are typical drying oils used in the manufacture of linoleum, Suitable dryiii,@ oils are characterized by being those in which oxidation yiel,l-s a substaitial amotint of the oxidized glycerides of linoleic and linolenic acids. Synthetic dryiilg oils, such as those derived from tall oil and other similar stibstances, can be used. In the production of linoleum binder, the drying oils can either be partially oxidized alone and thereafter blended with suitable resins, followed by furtber oxidatioii, or the raw drying oils can be blended directly with resins and oxidized in a single stage. The resinous material used is conventionally rosin or its derivatives, such as ester gum and the like; but oth-.r resinous n-laterials, such as cor-go ester, coumarone resins, krari giim, synthetic resins of the plienol-forinaldehyde type and the like can be used. During the oxidation process, it is conve,r@tional that small proportions of metallic dryers, such as the metallic salts of lead, manganese and the like, be used. At the conclusion of the oxidatibn, which by the single stage process normally requires from 12 to 30 hours at a temperature of 180' F., the mass of oxidized drying oil and resin is withdrawn from the kettle in the form of a rubber-like gel. This mass, after bei-iig cool--d, is mixed with pi,-Ments and fillers to produce the linoleum composition. The filler content will normally comprise a mixtl,re of vegetable fillers, such as cork, ivood flour and the like and mineral fillers, such as whiting, clay, asbestos and the like. The composition is pigmented usi@ng conventional organic or inorganic pigment, according to the particular color desired. Conventional linoleum compositions will nom-ially co@mprise froni 25 percent to 50 percent by weight of a blend of drying oil plus resin (normally referred to as linoleum binder) and from 50 percent to 75 percent by weight of pigments and fillers. The resin content of the linoleum binder is normally between 15 p,-reent ahd 35 percent by wei,@ht of the arrount of drying oil plus resin. Linoleum coi-nposition formulated as desrribed ab6ve is formed into a sheet by any of the techniques of sheet formation such as calendering or pressing. The sheet so formed becomes the base sheet upon which granular co.,nposition is deposited and into which the deposited compositio@i is embedded in accordance with the invention. The base sheet can be -'Lormed in any of the conventional decorative effects in accordance with well-l,,nown techpiques of the prior art, that is, the base sheet can be a plain colored sheet or can be in the form of a jaspe or marbleized decorative sheet. It is particularly e-ffective, however, for the base sheet to be formed as a granite-type decoration, since in this way the decorative characteristics of the fipished product will remain substantially unchan.-ed as the t)roduct wears. In the preparation of the grai-lite-type decoration, the lipoletim coniposition is ordinarily formed as fine multicolored granules. The colors choseii are preferably the same as the colors desired in the wearing surface of the finished product. Granulated linoleum composition is niost conveniently prepared by passing hot sheeted coniposition over the surface of a roll from Nvhich granules are gouged by a plurality of pins. This technique known as scratching is well-known in the linoleum manufa--turing art and the granular material so produced is Imown as scratch. lp the preparation of a granite effect base sheet for iise in the invention, multicolored scratch composition rolls. The front calend!,r roll has a teriiperalure between about 40' F. and aboul 100' F. and the back roll is somewhat warm,-r w:th a temperature between about 90' F. and .5 about 130' F. Uhder these conditions, a multicolored sheet is produced havin.- a fine grahite-type appearance. Where it is des,'@.red that the base sheet have a minimum of directional characteristics in the decorative effect, one or both of the calender rolls can be kept clean in accordance 10 with the procedure described in U.S. Patent No. 2,624,068, wliieh issuc-d on January 6, 1953 to Joseph F. Dobry. A base sheet having a graiiite ertect can also be produced by moldin.- fine scratch coinposition in a press. However, the use of calender rolls is particularly desirable since 15 calendering affords a method oj' producin.- the base sheet continuously' In the production of products in accordance with the invent;on, it -is essential that the base sheet be thinner than the final linoleum compbsition sheet produced. The 20 base sheet is preferably about 5 to about 20 mils thinner than tiie fi@nished linoleum composition sheet with a ran.-c of abolit 7 to about 15 mils thinner being particularly e&.ctive. Liroleum is conventionally made with a decorative wear;ng surface having a thickness in the ranle 25 of 0.032 to 0.125 ir@ch. Most linoleum, however, is produc.-d having a wearing stirface with a thickness of about 0.050 inch which is referred to as standard gauge linoleum. In the production of linoleum, the decorative sheet prodticed is normally somewhat thicker than the ultimate 30 pro(iuct gauge desired in order to compensate for small amouhts of gauge reduction in the finishing unit and to compensate for slight shriiikage of the composition sheet duriig cure. In the production of standard gauge linoletim, the decorative sheet produced iii the sheet-forniing 35 process normally has a thickness of about 0.050 inch. Therefore, in the production of standard guage linoleum in accordance with the invention, the base sheet should have a thickness of about 0.030 to about 0.045 inch with a range of 0.035 to 0.043 inch being particularly effec41) t,.Ve. It is apparent, however, that the invention is also applicable to the production of decorative linoleum composition sheets having a thickness different from that used in normal standard gauge linoleum Production. In accordance with the invention, decorative linoleum 4.5 composition granules are distributed on the surface of a base sheet in the form of regular or irregular pieces. Preferably, the decorative composition should be scattered on the surface of the base sheet which shows the least direction. -VVhen the base sheet is produced by calen50 dering the surface showing the least direction will be usually the surface formed in contact with the cooler of the calender rolls. In one embodiment wherein granules of two dist@@'nct sizes are used, the fine granular linoleum coml,)osition is preferably in the form of scratch with a r,5 part@cle size ran(,,e in the order of 0.02 to 0.06 inch in maxiinum dimension. The scratch is prepared in a blend of colors in accordance with the desired decorative effect and as d,-scribed above, the color blend is t)referablv compatible with or equivalent to the color blen-d used in Go the preparation of the base sheet. The scratch composition scattered upon the base sheet in accordance with the invetition can be prepared from composition having a lower binder content than the composition used to form the base sheet. Also, the scratch col-nposition can be aged ,5 for a f@-w days which serves to minimize distortion and direction during the subsequent embedding operation. Also, the scratch can b.-- formu]aled to produce a harder composition stich as by using less binder. in this embodiment, the mtilticolored scratch composi70 t'on blend is scattered -as a thin uniform layer over a surface -of the base sheet, preferably the scratch will cover from 75 p.-rcent to 100 p-@rcent of the surface area of the base sheet. Any of the techniques adapted to obtaining a fine unifbrm distribltion of -ranular material can be used 75 to deposit the scratch composition iipon the base sheet.
[4]The rotating drum type f@@ellor illustrated in FIGURE I is particularly adapted to uniform feeding of linoleuni composition. The speed of rotation can be synchronized with the rate of motion of the base sheet to insure uniform application of scratch composition. Other types of fee,ders can also b,- used such as vibrating feeders, shakinfeeders and the like. It is essential, however, that the particular feeding device used be capable of distributing a thin uniform layer of scratchcomposition upon the surf am of the base sheet. After the fine scratch composition has bezn deposited -apon a surface of the base sheet, the larger pieces lor chips of linoleun-i composition are then applied to the layer of fine scratch compo-sition. In order to obtain the desired terrazzo or spatter design decorative eff,--ct, these chips should be considerably larger in surface area than the. scratch composition applied to the base sheet. The chips can be formed in any desired geometric shape, such as squares or rectangles, but irregular shapes produce very unusual effects. The chips will normally be from about 0.10 to about 1 inch in maximum dimension with a range of about 1/8 inch to about 1/2 inch being par-ticularly effective. The chips caii be formed from coarse scratch composition having the desired size r-ange or can be cut or broken from linoleum composition sheets. In order to riinimize distortion of the chips during the subsequent embedding step the composition used can have a lovier binder content that that of the base sheet compbsition or the chips can be aged for several days prior to use in order to increase their hardness. A percentage penetration of about 14% to about 22% for the composition of the chips is particularly effective. This is in comparison to a base sheet having a percentage penetration of over 22% to about 40% or ev,-n higher. Usually, the chips shouid have a percentage pen@.-tration of at least 25% high,-r than the base sheet. The chips should have sliostantial thickness in order that they can be embedded deeply into the decorative wearing surface of the finished product. Thus, the chips should be from about 0.75 to abotit 2 tirres the thickness of the base sheet with a range of about 1.0 to about 1.5 times the thickness of the base shp-et being particularly effective. The chips are scattered on the uniform layer of scratchcomposition to cover abou-t 1 to aboLit 20 percent and preferably about 2.5 to about 10 percent of the surface area thereof when used with the finer granules. When th-, chips are used without the fine granules, a coverin.- of up to about 90 percent can be obtained with from 60 to 80 percent being preferred. The actual coverage depends mainly on the particular decorative effect desired. The chips should Dreferably be prepared in a number of colors for novel results. It is essential that the chips be scattered uniformly over the base -sheet. Any techniques of feedina which are adaptable to the uniform distribution of linoleum composition can be used. The rotary drum feeder illustratpd iii FIGURE I is a particularly effective type of feeding device but,other types of feeders can be used such as vibrating feeders @and the like. The chips can, if desired, be combin-,d with the fine scratch composition and feed upoii the s rface -of the base sheet in a single feeding operation. It is more desirable, however, to use separate feeders in order that the pieces are uniformly distributed over the layer of fine,scratch composition. The base sheet having the decorative composition uniforr.ily deposited upon a surface thereof is then passed between spaced calender rolls in order to er-qbed the decorative composition into the base sheet and consolidat@- the mass into an integral linoleum composition sheet. The calender roll which engages thedecorative composition should -preferably be chill--d in order to minimize distortion of the decorative composition being embedded. A temperature range for this roll of 40' F. to 90' F. is desirable, although higher teniperatures can be utilized. The roll which engages the back of the base sheet is usually heated to a relatiiely high temperature in the range of about 150' F. to about 275' F. The spacing between the rolls should be adjusted in accordance with the desired product gauge. As discussed above, in the production of standard gauge linoleum, the roll spacing should be about 0.050 inch. This spacing should be about 5 to about 20 mils greater than the thickness of the base sheet with a spacing of 7 to 15 mils greater than the thickness of the base sheet b-@ing partictilarly effective. If the sheet is on a 10 felt backing during the embedding procedure, the appareiit spacing of the rolls can be somewhat less due to compression of the felt. In addition, the linoleum composition can have a spri-.ig-back as hi.-h as 30 percent as it passes from the calender rolls which would also affect the spacing 15 of the rolls. In the passage of the she--t having the decorative composition deposited upoll a surface thereof between the rolls, the chips become deeply embedded into the sheet prodticed. When using the fine scratch composition, it is con20 solidated into and on top of the base sheet to form an inte.-ral decorative linol-,um eomposition sheet. In some instances, a light pressure can be applied to the decorative composition which have been deposited upon the base sheet prior to the embedding and consolidation. This 25 light application,of presslire is particularly desirable where the base sheet must pass either upwards or downwards in order to enter the nip betvieen the calender rolls. In these cases, the light knplienlion of pressure serves to bond the composition to the base sheet so that they do not slide or 30 fall off the base sheet during its passage to the calender rolls. 14owever, where the calender rolls are so placed that the base sbeet can travel horizontally into the nip, this light application of pressure is not necessary. It is a significant feature of the invention that decorative 35 coniposition is e Mbedded into the base sheet without apprecia:ble distort:@on in the shape of the composition. In addition, the embeddin.a is carried @out without the development of tensions in the base sheet which, -should they @occur, rn@'@ght result in tearing of the sheet durin.- its pas41,) sage through the embedding calender. A linoleum composition sheet, particularly when hot, is w--ak and thus a-iiy noii-uniform tensionsdeveloping across the width of thp, sheet can readily result in tearing or breaking of th-@ @shect. Tensions in the base sheet and d@istortion in shape i@' 5 of the decorative compositi@on are eliminated in accordance with the invention by eliminating any @auge redtiction of the base sheet during its passage through the embedding calender. In the passage of sbeet material through a calender, an ef@ective m@-ans of determining gauge reduc50 tion in the sheet is a comparison of the sdeed of sheet motion before and after the calender. Where the speed does not change, there is no gauge reduction as the sheet passes between the calender rolls. In accordance with the invcntion, the differeilce between the thickness of the final deco5a- ra@tive sheet and the base sheet is adjusted in accordance with the volurne of decorative composition scattered upon the base sheet a-.id embedded therein. It is essential in carrying out the method of the inventioli that there be -substantially no changc in the speed oL' the sheet as it passe@ 60 throtigh the embedding calender. This condition of no change in speed indicates that there is no reduction in the gatige of thp. base sheet as it passes through the embedding calender. In actual practice, minor changes in sheet speed can result but the sheet leaving the embedding 65 should not travel at -a speed which is more than 10 p-.rcent faster than the speed of the base sheet feeding the calender. It has been found that where there is an increase @of more than 10 percent in sheet speed, bagginess and tensions develop in the base sheet with the result that the 70 base she&t tears as it passes through the calender. T decorative linoleum compo:sition sheet leaving the einbedding calender has decorative pieces of linoleum composition embedded deeply into the thickness thereof. The depth of pen-,tration normally ranges from 40 percent 75 up to 90 percent of the thickness of the sheat. The place-
[5]me,@it of the embedded pieces over the surface area of the sheet corresponds to the placement of the pieces upon tl-ae fine scratch composition layer deposited upoti the base ,sheet. The fine scratched composition is also embedded into the surface of the sh.-et and blends with th,-- multicolored composition us@-d in forming the base sheet. Tlius, the color chara:cteristies in the product are mainta,'ned as the product becomes worn after installation. Ti'ie Imbeddin.- occurs without substantial -listort.;on in the shape of the pieces with the result that the - decorative linoictim 10 composition sheet has a non-direct-lonal - ann.--,qrance. This appearance is remark-ably sim;lar to decorativ,- effects which heretofore have b-,enobtair@able only by depositi-.-Ig linoleum composition in di'@Terent colors through steneis follovved by molding in an intermittently-operated flat bed 15 press. The fine scratch coniposition deposited upon the base sheet as a thin layer s,-rves a two-fold purpose. First, the fine granules are embedded iito the - base;sheet, thereby minimizing the effect of any d-irectional ch,-tracteristics in 20 the base sh---.t decoration. This is an essential feature oi' ,obtaining the desired non-directior,@al app@,arance in th-- finished product. Second, the layer of fine scratch composition serves to markedly -reduce distortion i-ri the shape of the decorative pieces embedded into the base sheet. As 25 a piece is forced into the hot linoleum composition base -sheet heat tra-@is_fer from the sheet to the piece tends to soften it. Thcre is, therefore, a tendency ior the p@,ece to become distorted. However, the layer of fine scratch composit@ioa forms a matrix which surrounds th-- p,:ece and @90 serves to preserve the shape of the piece as it is forced into the base sheet. In the absence of th.- layer of fine scratch composition distortion in shape of the pieces embedded into the base sheet can cause mark--d directional characteristics in the appearance of th.- product. If the fiii@e scratch -,5 layer is not used, it is preferred to embed t@x pieces with as littl-- lateral force as possible. A finish;ng unit such as illustrated in FIGURE 3 is particularly siiitable for such embedding. The base sheet serves as a soft resilient base into which 40 both the ftn-- scratch and decorative pieces are embedded. The presence @of a linoleum comi)os@tion bas-- sheet is essenti,al in the production of products in accordance with the invention. If one attempts to deposit a layer ol' fine scratch composition and decorative pieces upon a fir-iii backing 45 such as impregnated Ielt, distortion and direction develops i-Ti the prod-act with the result that it does not have thpdesired non-directional charact.-risties. Linoleum composition in sheet form must be bonded to a strengthenin.- baclcl:ng prior to ctire -of th@- composition ro to produce finished linoleum. The backin.- is a@l esser.,tial cler@ient in the fir@ished product since it irr@parts to the product the ability @to withstand strains resulting from handling the product during installation. In addition, the backing is necessary since uncured linoleum compositioil 55 is relatively weak and soft and l@inoleum composition sheet3 hun- in curing ovens without a backing wo-ald invariably tear and break. Backings of woven fabric ' such burlap, cottoii and the lilce, or felted fibrous sheets are well-known in the linoleum.art. Felted fibrous sh@-ets, prepared from e@ ,o fibrous riaterials on a web-forming machine, slch as a Fourdrinier or cylinder r-,-iachine, are ideal backing she,- ts for linoleum if impre.-nat--d Nvith a water-T)roofin,a and strengthening saturant. Suchsaturants as asphalt, thermoplastic resins stich as polyvinyl acetate, - coui-naron@- resins, el I and the Eke, clastomeric resins, such as rubb@-r, butadienestyrene copolymer, polymerized chloroprene ard the like, @and thermosettin.- resiis, such as phenolformaldebyde !resin, oxidized natural and synthetic dryin.- oils and the lik-e can be used. The decorative she,--t leaving the em- 70 bedding calender is lamiiated to a ba:ck@in.- by coptact with the backing between pressure rolls. Lamination can also be brou.-ht about in a flat bed press but continuoiis lamination of the decorative sheet to the backir@g is part,.cularly effective. 75 If the base sheet and the decorative chips, graililes or @.cratch are at different temperatures at the time of embeddir,@g, it can result i@i the formation of small bulges in the suri-ace of the base sheet which bears the decorative pieces' This is dt,.e to thermal expansion of the chips after emboddin,-. If th@.'s occurs, the sheet can be subjected to a further pressirg stop after the pieces have b,-en ernb.-dded t@li-@rein. P.,ior to this firkal pressing, the sheet is preferably heated to a temperature between about 120' F. to about 140' F. The heated shept is then passed beneath a pressiig surface. The final pressiig can b.- carried oi-it betweei ca!etider rolls or in a flat bed or rotary press. It is preferred that the pressing surface which engag--s the decorative surface of the product be maintained at normal room temperatures, that is between about 50' F. and about 90' F. The product is then stoved or cured in the manner conventional in the manufacture of linoletini surface coverin.-S. Conventio-rially, the product is hun.- in long loops in large oiens or stovesand gels at a temderature of about 140' F. to about 180' F. for a period of abotit three tc) six vieeks. The cured product, removed from the stove, can be Lised in the form of sheets or can be cut up into tilp-s or other ai)PrODriate shkoes as desired. After cure, th-- prodtict can be bonded to a resinous foam backing, such as foam rubber or foam vinyl resin where a pridduct with high resilience is desired. Tha following examples are given for purpose of illustration: Example 1 A mixture of 75 parts linseed oil and 25 parf,s rosin was ag-@tated in a Lettle in the presence of air at a temperature of 180' F. until it became a rtibber-like get to form a linoleum b-inder. Batches of linoleum composition were prepared in different colors, each batch havin.- the following composition: Percent by weight Linoleum binder ----------------------------- 37 Wood flour ---------------------------------- 29 Pigment and filler ----------------------------- 34 100 Each batch was milled and scratched to produce a fine scratch having an average particle size of 0.040 inch and the scratch blended to prepare a multicolored blend as follows: Percent by weight Light gray ----------------------------------- 40 Medium gray -------------- 30 Dark gray ----------------------------------- 30 100 This blend was sli--eted between a pair of calender rolls, the upper roll at a temperature of 50' F. and the low.-r roll at a tempe,@ature of 110' F. The restilting sheet, the base sheet for use in the inveition, had a thickness of 0.045 inch and had a granite type decoration. Additional batches of fine scratch compositicn were prepared and blended in the same color proportions as tabulated above using linoleum composition formulated as follows: Percent by weight Linoleum binder ------------------------------ 34 Wood flour ---------------------------------- 29 Pigment and filler ----------------------------- 37 100 This blended fine scratch composition was scattered over about 90 percent of the surface of the base, sheet forined against the cooler roll in a thin layer the amount of scratch being 15 perce,nt by weight of t@e base sbeet over a unit area. Linoleum composition sbeets were prepared in red,
[6]white, blue, black, green and yellow with a thiclmess of 0.072 inch using compositions with 34 percent linoleum binder content. These sheets were cut into irregular pieces having maximum face dimensions of about 1/4 inch. The chips were blended with equal proportion,s of each color 5 in the blend and scattered over the thin layer of fine scratch composit ' ion in an amount of 4.5 percent of the surface area of the base sheet. The deposited pieces represented 7 percent by weight of the base sheet over a unit area. 10 The base sheet having a layer of fine scratch and deposited pieces upon the surface was passed into the nip b--- tween two calender rolls, the upper roll at, a temperature of 50' F. and the lower roll at a temperature of 250' F. The decorative sheet produced had a thiel-ness of 0.055 inch, 15 0.010 greater than that of the base sheet, controlied by the spacing between the calender rolls. The rate of sheet travel was constant through the calender. The decorative sheet was laminated to a sheet of asphalt tive wearing surface. The resulting product was cured at 165' F. for 4 vveeks to yield a finished linoleum having a wearing surface with a thickness of 0.052 inch, standard gauge. The decora25 tion was non-directional and had a pronounced resemblance to a spatter design effect. Example 2 A base sheet was prepared following the procedure of 30 Example I and calendered into a sheet having a thickness of about 0.035 inch. The uncured linoleum base sheet had a percentage penetration of 28 percent. . In a manner similar to that shown in Examr)le 1, linoleum composition chips having a percentage pene35 tration of 18'percent were prepared in green and yellow from a sheet having a thickness of 0.027 inch, by cutti-@ig into re.-ular squares of approximately 1/4 inch face area. The cwps were then blended in equal portions of each color and deposited on the surface of the base sheet in a '10 uniform, single layer. Sufficient chips were utilized to randomly cover about 80 percent of the surface area of the base sheet. The percent.age penetration of the linoleum coqlposltion is determl'ned by carrying out a penetration test. In accordance with this test, a 0.25 inch diameter sir).ooth 45 metal cylinder is placed upon a sample of a linoleum composit ' ion sheet and a weight of 6 pounds is applied for a period of 60 seconds. This corresponds to a pressure of 122.4 pounds per square inch. At the end of 60 50 seconds, the amount of penetration of the cylinder the sheet is measured. When a conventional Ran and Stickney Dial Gauge is used, the amount of p tration can be read directly on a dial at the con.-lusi of the test. The actual penetration divided by the thi 55 ness of the sheet is the percentage penetration at temperature of the sheet during the test. The term p centage penetration as used in the specifica . tion a clain-is refers to the resiilt of a determination made the method outlined above. The base sheet having the decorative chips on its sur60 face is passed into the nip of a finishing unit formed by a large drum and a rubber belt. The drum surface is maintained at a temperature of about 150' -F. and the temperature of the sheet when fed to the finishing drum is approximately 80' E. The finishing drum has a diamC)5 eter of approxiinately 6 -'Lect and the rubber b@-It is J'6rc-,d against the drum by a series of small presslire rolls surroundiiig approximately one-half of the circumference of the drum. The pressure on the base sheet and chips TO is adjusted to allow the production of a sheet having a thickness of about 0.50 inch. The sheet has the chips embedded in its surface w;tb approximately 0.003 inch of the thickness of the chips extending above the surface. The sheet had an unusual decorative textured appearance. 75 12 In accordance with the invention, a non-directional terrazzo or spatter design effect can be created in linoleum in t continiious process by calendering. The character of the decoration is preserved during wear of t@he product after it is installed. The method of the invention is adaptable to the production of linoleum in a wide range o decorative effects merely by changing the shape and distribution of the decorative composit@on embedded in the base sheet. The decoration can be changed withbut large extra investment as would be required in producing geometric inlaid rroducts or in the production of linoleum using stencils. The continuous calendering process is carried out without the development of excessive tensions in the base sheet. Aiiy departure from the above description which confornis to the present invent;@on is intended to be incILided witliin the scope of the claims. What is
