US 3259515 A
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y 5, 1966 c. PECKER METHOD FOR REDUCING GLOSS 0F PRINTED SURFACE COVERINGS, AND PRODUCT THEREOF Filed 001',- 12. 1962 ATTO ]N VEN TOR CALMAIV PEGKER @1 Rims QERQQU QEPSQQQ EQRSR United States Patent Office 3,259,515 Patented July 5, .1966
METHOD FOR REDUCING GLOSS OF PRINT- ED SURFACE COVERINGS, AND PRODUCT THEREOF Calman Pecker, Long Island City, N.Y., assignor to Congoleum-Naim Inc., Kearny, N.J., a corporation of New York Filed Oct. 12, 1962, Ser. No. 231,319 8 Claims. (Cl. 117-15) This application is a continuation-in-part of my copending application Serial No. 17,620, filed March 25, 1960, entitled Method for Reducing Gloss of Printed Surface Coverings, and Product Thereof, now abandoned.
This invention relates to decorative printed surface coverings having a wear resistant surface layer and in particular to a method of controlling the gloss of the surface of such products.
ecorative printed surface coverings having a felted fibrous backing are well-known in the art and find wide application as coverings for floors, walls and the like. In recent years, such products have come to be produced with a decoration printed by the rotogravure printing technique with the resulting thin design layer being protected by a clear layer of wear resisting composition. Clear vinyl resinous compositions have been used to form :the wear resisting top layer since vinyl resins have excellent properties of resistance to abrasion and to attack by chemicals of the type normally found in households.
In one widely used method of producing a rotogravure printed surface covering product, a felted fibrous sheet is impregnated with a strengthening impregnant such as asphalt, and the sheet is provided with a plurality of sealing coats of paint. The seal coats perform the desirable function of masking the color of the impregnant and, in addition, create a smooth, white surface suitable as a base for printing. After the seal coats have been applied to the felt backing, a decorative design is printed on the upper surface of the coated backing by means of high-speed rotogravure printing press. A layer of clear resinous composition is then applied over the decorative design and the sheet is passed through an oven maintained at temperatures up to 450 F. to fuse the resinous composition in order that the layer can obtain the optimum strength and abrasion resistance. The sheet, after cooling and inspection, is rolled up and packaged for sale.
It has been found that due to the high temperature treatment mentioned above, the resinous wear layer possesses an extremely smooth and glossy surface. The high degree of gloss possessed by the surface is in many instances undesirable since scratches, indentations and other imperfections caused by exposure of the covering to normal wear are readily apparent, thereby presenting :an unattractive appearance.
One of the methods commonly used to reduce the gloss is by contacting the surface of the resinous composition while heat softened with a matte-surfaced roll which produces minute irregularities in the surface. These surface irregularities have the effect of diffusing light striking the surface, thereby reducing the glare caused by reflection of light from an essentially smooth surface. The use of the matte-surfaced rolls to reduce gloss possesses some undesirable features. If it be desired to obtain varying grades of gloss in a product, the
matte-surfaced rolls must be changed since a given roll' produces -a single degree of gloss on a particular surface. Moreover, such matte finishing requires a pressure nip which necessitates large diameter, expensive rolls for wide webs.
It is an object of the invention to provide a simple method of controlling the surface gloss of a smooth resinous composition wear layer. Another object is to carry out such a method by utilizing conventional equip- It is a further object of the invention to provide a continuous method of obtaining a desirable degree of gloss of the wear surface of a printed surface covering without the necessity of heating or cooling the sheet. Other objects :and the advantages of the invention will appear hereinafter.
In accordance with the invention, a printed surface covering having a fused layer of wear resisting composition is passed to a printing cylinder or other coating means which places small transparent deposits of resinous printing ink spaced apart over the entire surface of the product. The printing ink is thereafter dried. The
' area of the ink deposits determines the gloss of the product in connection with the gloss of the deposits themselves. The smaller the deposits, the higher the gloss of the product and the wider the deposits, the less gloss. The gloss, therefore, is controlled by limiting the area of original surface exposed. The theoretical minimum gloss obtainable, therefore, would be complete coverage of the wear layer. It is essential, however, that the individual deposits be invisible to the eye.
The invention will be better understood from the following detailed description when read in conjunction with the accompanying drawing wherein FIGURE 1 shows a schematic representation of one embodiment of the invention and FIGURE 2 is a cross-section of the product provided in accordance with the invention with the upper surface greatly enlarged.
With reference to the drawing, a back sheet 11 hearing on the upper surface thereof a printed design layer 12 is fed from supply roll 10 to a coating operation generally indicated at 13. A film of liquid resinous composition 14 is applied to cover the printed layer 12 from a mass of resinous composition 15 by means of a doctor blade 16. The sheet is then passed through a hot air oven 17 in which it is supported by means of spaced rolls 18 to fuse the resin. The sheet emerges from the oven bearing an upper layer 19 of fused transparent resinous composition. The product is cooled by passing over cooling rolls 24, 25 and 26. The printed product passes from the last cooling roll and thence between a conventional ro-togravure cylinder 29 land a metal roll 30. The ro togravure cylinder places small spaced deposits 40 of printing ink on the surface of the product. The product 41 is thereafter passed to an oven 45 to remove the solvent from the printing ink thereby drying the ink. The dried product is cooled by passing over cooling rolls 5%) and wound on a collecting roll 51, inspected, packaged and collected on a roll.
The base upon which the decorative design is printed is most frequently a web of felted fibers. Gther material, however, can form the base such as paper, plastic sheets and the like. The felt generally is produced using a Fourdrinier or a cylinder paper machine with the thickness of the resulting sheet being that usually used in floor and wall coverings, that is, from 0.02 to 0.08 inch. The
fibrous material used is normally cellulosic in origin, although other fibers can be used including those of animal and mineral origin. The sources of cellulosic material can include cotton other rag material, wood pulp, including both ground Wood and chemical wood pulp, paper, boxes, or mixtures thereof in any proportion. The web can also contain fillers such as Wood flour.
The felt is normally strengthened and improved in water resistance by impregnation with a bituminous material. Numerous bituminous materials are well-known as impregnants in the production of printed surface coverings and include asphalts of petroleum or natural origin and tars and pitch residues or animal or vegetable origin. These materials can be treated to attain the desired physical properties of softening point or viscosity for satisfactory impregnation by such treatment as air blowing, steam distillation and the like.
Other impregnants for the fiber sheet can also be used to form backing sheets for use in the production of printed surface coverings in accordance with the invention. Such materials as phenol-formaldehyde and phenol-urea resins, polymerized vinyl compounds, such as polyvinyl chloride, polyvinyl acetate and the like, cellulose acetate, cellulose nitrate, butadiene-styrene copolymer, butadiene-acrylonitrile copolymer, natural rubber and the like can be used. Polymerizable materials can also be incorporated into the felt and the sheet subjected to heat to cure and polymerize the material. Such materials as natural and synthetic drying oils, mixtures of polyhydric alcohols and polybasic acids which cure to form polyesters, mixtures of polyhydric alcohols and polyisocyanates which cure to form urethane polymers, and the like can be used. In general, asphalt is the preferred impregnant due to its extremely low cost.
Prior to the application of the decorative design layer by printing, the base is provided with a number of seal coats in order to provide a smooth surface upon which the design can be printed. The seal coats serve to mask the generally dark color of the impregnated felt backing and also create a smooth uniform base for printing. The seal coats are preferably applied in the form of an aqueous dispersion of a vinyl resin in the presence of plasticizer and large amounts of pigments and filler. Seal coat systems of the type described in US. Patent 3,068,118, issued December 11, 1962 to John Biskup et al., entitled Decorative Surface Covering, are particularly effective.
The base sheet either in the form of a seal coated felt or other suitable printing base is then printed with a decorative design using printing inks which are compatible with the resinous composition wearing surface layer. Printed products having a wear surface layer are quite commonly printed by the high speed rotogravure technique. In this technique of printing, each color is applied from an etched cylinder in the form of closely spaced dots upon a back: ground which is usually white. The sheet is heated to dry the printing ink after each printing cylinder of the rotogravure printing press. Printing inks comprising vinyl resinous binders in organic solvents are most commonly used. In addition to the rotogravure technique, .the decorative design can be applied by any of the other rotary graphic art printing proceses, such as offset printing, lithography and the like. Alternately, the printed design can be applied by the flat bed printing process.
The wear surface layer can be applied as a plastisol, organosol, hydrosol or the like. It is normally preferred that the wear layer be of the type which requires fusion although it can be applied in other ways such as a solution where plasticized resin is dissolved in a suitable solvent. Alternately, the wear layer can be applied as a preformed filament or sheet of resinous composition which is laminated to the printed base sheet such as by using an adhesive or by heat. The composition of the wear layer is preferably a vinyl resin such as the widely used polymers and copolymers of vinyl chloride. Any of the other resinous compositions which form a translucent or transparent coating can be used, however. Typical of other types of resinous compositions are those containing polymerized vinylidene chloride, polymerized vinyl esters of a carboxylic acid having from 2 to 4 carbon atoms, polymerized lower alkyl acrylates such as ethyl acrylate, acrylonitrile polymers and styrene polymers. These resinous substances are conventionally plasticized to give them the desired degree of flexibility or softness. Typical of the plasticizers which are used are tricresy phosphate, dioctyl phthalate, polypropylene glycol sebacate, tributyl phosphate.
The wear composition is applied by any of the conventional techniques of coating such as reverse roller coating or doctor knife coating. After application of the clear wearing surface layer, the sheet is subjected to elevated temperatures to bring about fusion of the resin. Using a vinyl resin which is most commonly used in clear wearing surface layers, the layer must attain a temperature in the order of 350 to 375 F. in order to effect fusion. The temperature of the fusion oven and residence time in the oven are adjusted so that complete fusion of the wearing surface layer is attained. The product after leaving the fusion oven is cooled in any convenient way such as by passing around a number of metal cylinders which are frequently referred to as cooling cans.
In accordance with the invention, the cooled sheet bearing the layer of fused Wear resisting composition is passed from the cooling rolls to a printing operation which prints or otherwise applies a series of small spaced dots or spots of transparet printing ink on the wear surface. After application of the printing ink, the sheet is subjected to heat to remove the solvent from the printing ink formulation. The sheet is, then cooled, inspected, packaged and shipped for sale.
It is preferable to use a rotogravure printing cylinder since greater control of the gloss can be obtained. Such a cylinder may be engraved to a depth of either full tone, half tone, quarter tone, or any tone necessary to reduce the gloss to the desired level. The area of the printed deposits controls the gloss of the product, since the lesser of the wearing surface covered, the greater the gloss of the surface. The deposits diminish the gloss because the ink has a gloss less than the gloss of the wear layer. As is apparent, the minimum gloss obtainable is dependent on the gloss of the dried printing ink remaining after the removal of the solvent. The printing ink, of course, must be transparent to enable the design of the product to be visible.
The printed deposits can be formed from any of the conventional paints and inks which are normally used for application of a decorative design. The composition, when utilizing the preferred wear surface, is preferably formulated so that the binder of the printing composition contains an appreciable quantity of a vinyl resin dissolved in a suitable solvent mixture such as, for example, methyl ethyl ketone. Suitable vinyl resins include vinyl chloride polymers, such as vinyl chloride-vinyl acetate copolymer and vinyl chloride-vinyl propionate copolymer, vinyl butyrate polymer, vinylidene chloride polymer, vinylidene chloride-vinyl chloride copolymer, copolymers of vinyl chloride and vinylidene chloride with esters of maleic and fumaric acid such as dimethyl diethyl, and dibutyl maleate and fumarate, lower acrylate esters, such as ethyl acrylate copolymer, and the like. Extender resins, such as nitrocellulose, can be employed as a portion of the binder for the ink or paint. Fillers can also be added in small quantities to reduce the gloss of the ink itself.
By the method of the invention, various degrees of gloss may be imparted to a smooth surface covering simply by varying the depth or width of the depressions in the printing cylinder. It is of particular significance that varying degrees of gloss may be obtained by using continuous equipment. Previously, matte surface roll methods of reducing gloss were capable of effecting only one degree of gloss continuously, thereby necessitating changing of the rolls if a different degree of gloss were desired. It is also an advantage of the present invention that wider sheets of surface coverings can be treated since the pressure impediments of using extremely large matte surface rolls are avoided. A further advantage of the present invention resides in the fact that despite the gradual wearing away of the dots of clear ink, the transition to the surface of the product is not noticeable due to the normal dulling of the wear surface through abrasion.
The only limitation existing in the process consists of the number of deposits or dots of the ink that can be placed in a given area. Usually a density of dots produced utilizing from about 50 to about 300 line screen for engraving the printing cylinder is sufiicient. Below 50 lines per inch, the deposits are visible to the ordinary eye and the desired effect is lost. In this range, the number of deposits per square inch would vary from about 2500 to about 90,000. As is apparent, the spacing of the dots has to be uniform to obtain a uniform gloss level. As indicated previously, the size of the deposits in area determine the gloss through the amount of fused wear layer exposed. Preferably, the gloss desired is obtained when about 25 to about 50% of the wear layer is covered with deposits of ink. If the frequency of the dots be so great that the dots, on heating, flow together to form a smooth, uniform layer, then the purpose of the invention will essentially be defeated. It is, consequently, necessary that the dots of ink deposited by the printing cylinder be sufficiently separated so as to prevent flowing together on removal of the solvent.
In Table I is shown examples using a gravure plate consisting of two 120 line screen sections (120 dots per linear inch), one of quarter tone, the other of half tone. All gloss readings were taken with a 60 meter. The printing ink was a solution of vinyl chloride resin in methyl ethyl ketone. The surface printed was a fused layer of vinyl chloride resin.
TABLE I Gloss Reading Surface Control Tone Tone Typical printing compositions for use in the invention are as follows:
These compositions can be utilized for printing the decorative design by the addition of suitable pigments.
Typical wear layer formulations are as follows:
Example 3 Pants Vinyl chloride-vinyl acetate copolymer 50 Tricresyl phosphate 15 Xylene 40 Example 4 Pants Vinyl chloride polymer 50 Dioctyl phthalate l7 Toluene 30 Example 5 Pants Vinyl chloride polymer Dioctyl phthalate 13 Tricresyl phosphate 7 Polyester plasticizer 7 Stabilizers 4 Mineral spirits 17 Methyl ethyl ketone 2 The following example is a typical method for carrying out the invention.
Example 6 solids) 25 Whiting 247 Sodium alkyl aryl sulfonate 0.6 Sodium alkyl sulfate solution (5 percent solids) 6 Water 75 The felt was dried at a temperature of 150 F, for minutes. A dry seal coat weighed 0.8 pound per square yard of felt.
A decorative design was applied to the surface of the coated felt by a multi-cylinder rotogravure printing press using a printing ink having the formulation of Example 1. Between cylinders and after the last cylinder the sheet was subjected to heat to remove solvent from the printing ink formulation. The formulation as shown in Example 3 was applied to the surface of the decorative design -by means of a roll coater. The sheet was then passed through a forced hot-air oven in which the organosol obtained a temperature of 350 F. thereby removing the solvent in the organosol and solvating the polyvinyl chloride resin by the plasticizers in the fusion process. The fused sheet was thereafter cooled and passed through a single printing cylinder whereby a printing ink comprising a solution of vinyl chloride resin in methyl ethyl ketone was applied .to the surface in one-quarter tone depth. The printing ink was thereafter dried by removal of the solvent and the product cooled, inspected and packaged for sale. The gloss of the surface of th product using a 60 gloss meter was 33 whereas the initial gloss was about 55.
Any departure from the foregoing description which conforms to the present invention is intended to be included within the scope of the claims.
What is claimed is:
1. A method for controlling the gloss of a surface covering having a smooth, glossy, resinous composition wear layer which comprises printing on said wear surface by an engraved printing cylinder, 2. series of small, uniformly spaced deposits of a translucent liquid resinous composition having a density of at least 2500 deposits per square inch and thereafter heating said composition to solidify the printed composition, the area of said deposits determining the degree of gloss of said wear layer.
2. The method of claim 1 wherein said resinous composition wear surface is a vinyl composition and said trinslucent composition is a vinyl composition printing in 3. The method of claim 1 wherein said spaced deposits of translucent composition are uniformly distributed within the range of about 2500 to about 90,000 per square inch of surface covered.
4. A method for controlling the gloss of a surface covering having a smooth, glossy, resinous composition Wear layer which comprises coating one surface of a felt sheet impregnated with a strengthening and waterproofing resinous material with a pigmented resinous composition, heating to solidify said coating, printing a design on said solidified coating, completely covering said printed coating with a thin layer of vinyl resinous composition, heating to harden said vinyl coating, pressing said hardened vinyl coating in contact with an etched printing cylinder containing a translucent vinyl ink whereby small dots of said translucent vinyl ink are placed on the surface of said vinyl coating in uniform spaced relationship having a density of at least 2500 deposits per square inch and thereafter heating said sheet to dry said vinyl ink, the area of said printed dots determining the degree of gloss of the surface of said vinyl coating.
5. A smooth, decorative surface covering for floors, Walls and the like having a controlled gloss which comprises a smooth layer of wear resistant resinous composition covering one surface of a backing .and a series of minute raised deposits of a translucent resinous composition in uniform, spaced relationship having a density of at least 2500 deposits per square inch on the .top surface of said smooth layer, the area of said raised deposits determining the degree of gloss of said wear surface.
6. A smooth, decorative surface covering for floors, walls and the like having a controlled gloss which comprises a smooth layer of wear resistant vinyl resinous composition covering one surface of a backing and a series of minute raised deposits of a translucent resinous composition in uniform, spaced relationship having a density of at least 2500 deposits per square inch on the top surface of said smooth layer, the area of said raised deposits determining the degree of gloss of said wear surface.
7. A smooth, decorative surface covering for floors, walls and the like having a controlled gloss which comprises a felt base impregnated with a strengthening and waterproofing resinous material, a smooth, resinous coating on one surface of said felt, a design printed on the exposed surfac of said coating, a smooth, resinous composition wear surface covering the entire surface of said printed coating and a series of minute deposits of resinuous composition in uniform, spaced relationship having a density of at least 2500 deposits per square inch on the exposed surface of said wear layer, the area of said raised deposits determining the degree of gloss of the surface of said surface covering.
8. The decorative surface covering of claim 7 wherein said deposits are uniformly spaced and comprise about 2500 to about 90,000 per square inch of exposed wear layer surface.
References Cited by the Examiner UNITED STATES PATENTS 2,470,493 5/1949 Karfiol et a1 11715 X 2,742,377 4/1956 Bezman 117-140 X 2,769,726 11/1956 Wetterau et a1 1l7-76 2,861,007 11/1958 Hazeltine 117-38 X 2,920,977 1/1960 Adams 11715 2,943,949 7/1960 Petry 117-15 X 2,961,332 11/1960 Nairn 11715 X 2,989,414 6/1961 Pcckcl' 117-14 3,068,118 12/1962 Biskup et al 11714O X WILLIAMD. MARTIN, Primary Examiner.
H. E. COLE, W. D. HERRICK, Assistant Examiners.