Abstract:
A web of indeterminate length carrying thermally transferable material, usually referred to as hot stamp tape, is structured to provide an improved simulated wood grain pattern on a substrate after transfer to the substrate of transferable portions of the tape. The web or tape may be provided in sheet form. The structure comprises &#34;ticks&#34; or discrete linearly oriented spots of material having low specular reflectivity coated on a matte carrier sheet, as by printing, and a layer coated thereon to provide the top layer of the transferred material, which replicates the surface of the carrier sheet and the coated &#34;ticks&#34; or spots.

Description:
CROSS-REFERENCES 
     This application is a continuation of application Ser. No. 338,238, filed Mar. 5, 1973 and now abandoned which, in turn, is a continuation of Ser. No. 233,463, filed Mar. 10, 1972 and now abandoned which, in turn, is a division of Ser. No. 188,423, filed Oct. 12, 1971, now U.S. Pat. No. 3,666,516. 
    
    
     FIELD 
     This invention relates to hot stamp tapes and more particularly to webs comprising heat transferable coatings. 
     PRIOR ART 
     The instant invention represents an improvement on the disclosures of the following patents: 
     
         U. S. Patent No.           Patentee   Classification______________________________________3,467,538       Best        117-83,054,715       White       156-2333,252,847       Morgan      156-2333,434,862       Luc         156-234X______________________________________ 
    
     SUMMARY 
     Simulated woodgrain patterns have been provided on many surfaces in recent years. Examples include countertops, wall panels, cupboard doors, radio cabinets and the like. Many of these have been provided by printing a woodgrain pattern on paper, laminating the paper to a substrate and covering the paper with a layer of synthetic resinous material. This has been particularly true in the case of countertops and wall panels. 
     In other instances, a woodgrain pattern has been provided in a transferable layer of a hot stamp tape (or web) and then, by hot stamp transfer, the transferable portion including the woodgrain patterned layer has been transferred to and adhered to a substrate. 
     More recently, in order to better simulate the grain of wood, it has become common to emboss linearly oriented spaced-apart depressions into the surface during or after transfer, the embossed portions being referred to in the art as ticks. Alternatively it has been well-known to provide the substrate with such ticks by molding or embossment prior to applying a coating thereto and then forcing the coating down into the ticks. 
     Ticks which have been provided in this manner have aided in providing a realistic simulation of a wood grain but have not been considered to provide optimum simulation. 
     In accordance with the present invention, it has been found that a highly non-specularly reflective surface portion of a coated surface more nearly simulates to the eye the natural tick appearing in actual woodgrain than does a mere depression. The actual ticks in actual wood appear to be partially depressed as is the case with embossment. However, they also differ very markedly; that is, to an extremely high degree, in specular reflectivity with respect to the portions of wood immediately adjacent the ticks. This latter property appears to be far more important in providing optimum simulation of the grain patterns of actual wood than does providing a depression as in the case of either embossment or molding of depressions in the substrate. 
     Thus, both the discovery involved in recognizing this fact and also the structure and method for providing improved simulated wood grain patterns constitute parts of the instant invention. Prior to the instant invention, it had not been possible to provide simulation of such non-specular reflectivity characteristics. 
     Accordingly, I shall describe a preferred embodiment of my invention to provide ticks which are substantially or nearly non-specularly reflective; that is, have a specular reflectance below a value of 25% at 60°. 
     I first provide a carrier sheet or web which may be any carrier sheet or web of the prior art; for example, a polyester film such as &#34;Mylar&#34; (trademark of DuPont), &#34;Melinex&#34; (trademark of Imperial Chemical Industries), or a web of cellophane or cellulose acetate or paper. I prefer to utilize a polyester film, particularly Mylar and I have found that to provide optimum results, I may provide this film as matte surfaced Mylar. A matte-surfaced Mylar may be provided by incorporating an inert particulate substance in the formulation during early stages of manufacture which affects the surface during later biaxial orientation or by embossment or sand-blasting or chemical coating. 
     The carrier may then be coated on one surface with discrete spaced apart portions or ticks of a layer of synthetic resinous material in such fashion as to provide on the surface of each tick, a surface having very low specular reflectance. If desired, a primer coat may first be applied in the pattern of the ticks and the tick coat applied on top of and in register with the primer coat. Coating may be accomplished by any suitable means such as by silk screening or spraying through a mask or by gravure printing or printing from the surfaces of characters. The composition is one which shrinks during drying to provide a sufficiently crinkled or otherwise irregular and non-glossy surface to provide the desired low degree of specular reflectivity. The discrete spaced apart portions or ticks are non-heat-transferably adherently attached to said carrier sheet, so that they will not transfer from the carrier sheet when subjected to the heat and pressure of the transfer operation. 
     A release coating may then be applied which may be of conventional form and may thus be based on paraffin wax or the like. The normal characteristics of a release coating are that it melts or softens at a temperature below that of other layers in the sheet so that neither the carrier portion which remains behind or the transferred portion (which may be one layer or may be as many as eight or ten layers) is melted or softened, except that the surface of the layer adjacent the substrate is sufficiently softened or made sufficiently tacky to provide adherence to the substrate. 
     Extreme thinness of the release coating is absolutely essential if not entirely critical. Thus, the release coating must be relatively thin relative to the size of the bumps in the nearly non-specularly reflective surface of the coated ticks, to permit subsequent replication of these bumps. 
     A layer of replicating synthetic resinous material is then coated relatively thickly over the release coating so that the thickness of each heretofore coated tick is either somewhat less or at least not much greater than the thickness of this newly coated layer, the newly coated layer being of synthetic resinous material suited to replicate the surface of the carrier sheet and the surfaces of the heretofore coated ticks. This layer may carry coloring material or may be transparent and may be adapted to be adhered directly to a substrate or may be provided with additional layers which may comprise coloring material and/or tackiness characteristics for providing ahderence to a substrate. 
     For example, it is normal to provide a simulated woodgrain pattern as a plurality of printings of different colors overlying each other and a coating is necessary for each such color. Coatings embodying all these colors may be placed over the replicating coating and the last of such color-containing coatings or an additional coating may be of a composition that provides the desired degree of tackiness during heat transfer to provide adhesion to the substrate. 
     Although carrier sheets either having a high degree of specular reflectivity, that is, being highly glossy or having a matte surface, that is, having a lower degree of specular reflectivity, have been described, the carrier sheet surface may have any suitable degree of specular reflectivity desired for any particular purpose. 
     This invention is not limited to providing simulated woodgrain patterns but may be utilized to provide any desired pattern having coated surface portions which vary greatly in specular reflectivity. Thus, on a carrier sheet having high, medium or low specular reflectivity, there may be coated not only one group of ticks having a particular set of surface characteristics, but there may also be coated additional groups of ticks to provide any desired number of groups, each group having a particular surface characteristic or characteristics which need not be the same as that of any other group coated thereon. 
     The replicatory coat then replicates all characteristics of all the surfaces presented by all such ticks or other coating portions coated thereon, plus the uncoated exposed portions of the carrier sheet. 
     OBJECTS 
     It is, therefore, an object to provide a hot stamp tape or web suitable for providing an improved simulated woodgrain pattern on a substrate. 
     Another object is such a web comprising coating ticks having low specular reflectivity and a replicating coating adapted to provide portions having corresponding low specular reflectivity after transfer. 
     Another object is to provide such a replicatory coat with two different degrees of reduced specular reflectivity. 
     Further objects will become apparent from the description. 
    
    
     DRAWINGS 
     In the drawings like reference numerals refer to like parts and: 
     FIG. 1 is a cross-sectional schematic view of one embodiment of the method and article of the invention; 
     FIG. 2 is a cross-sectional schematic view of the embodiment of FIG. 1 after completion of the process; 
     FIG. 3 is a cross-sectional schematic view of another embodiment of the process and article; 
     FIG. 4 is a cross-sectional schematic view of the embodiment of FIG. 3 after completion of the process. 
    
    
     DESCRIPTION 
     Referring now to FIG. 1, a carrier sheet A may be provided with primer coat portions B which may be provided thereover with tick coat portions C. A release coat D may then be provided and overlying the release coat there may be provided respectively a replicating layer E, an abrasion resistant layer F, a second abrasion resistant layer G, a color coat H, another color coat I, and an adherence promoting coat J. 
     Heat as indicated by arrows 10 and pressure as indicated by arrows 11 may be applied to force the laminar assembly 13, consisting of layers A thru J as described, against substrate 14. After thus applying heat and pressure, the carrier sheet and layers B and C and D attached thereto, may be removed to provide the article of FIG. 2, wherein areas of low specular reflectance are indicated at 15 and areas of specular reflectance differeing therefrom are indicated at 16. 
     In FIG. 3 is shown an embodiment corresponding to that of FIG. 1 wherein many layers are omitted, layer E provides a combination replicating, release, color, and adherence coat. In FIG. 4 is shown the article which remains after completing the process of FIG. 3 and removing sheet A having coating C attached thereto. 
     Coatings B and C are preferably applied by gravure printing but may be applied by silk screen printing, letter press printing, or the like. All other coats or layers may be applied by any suitable coating means such as by Meyer rod or reverse roller coater. 
     Below are given specific examples of suitable formulations for each coating layer together with particular characteristics thereof. 
     The carrier sheet which is preferably in web or tape form may be, as described above, a polyester film such as Mylar or a web of cellophane or cellulose accetate or paper. Mylar having a thickness of from 1/2 mil to 2 mils is preferred. For a preferred embodiment, it is desired to provide matte Mylar having a specular reflectance at 60° to the horizontal in accordance with ASTM standard D523 of 35% to 60% but in certain embodiments glossy or non matte Mylar which has a specular reflectance determined in like manner of on the order of above 90% and generally on the order of 95% or above may be used. 
     In Table I are shown the layers present in the various examples. Since the following three layers carrier sheet, tick coat, and replicating coat are present in all examples, these are not included in the table so that Table I only relates to nine examples although thirteen examples are presented; in the examples 10, 11, 12, and 13, the only layers present are carrier, tick coat, and replicating coat. 
     The primer coat as provided serves the purpose of providing for improved adherence between the tick coat and the carrier sheet and it may be omitted if adherence of the tick coat to the carrier sheet is adequate without the presence of the primer coat. 
     The release coat is generally preferably a material such as a wax or the like; either natural wax, paraffin wax, or a mixture of thereof, or a mixture of wax with other substances, may be used; but it is generally a waxy substance characterized by having a softening range rather than a clear softening point. The softening range or softening point of the release coat is generally preferably lower than the melting or softening points of the carrier sheet and all other layers in the laminar assembly so that when subjected to heat the softness of the release coat when heated permits the replicating coat to be released therefrom. 
     The replicating coat may in suitable instances be provided with release properties so that when subjected to suitable heat and pressure during hot stamping it is suitably released from the carrier sheet without the presence of a separate and a distinct release coat. 
     Abrasion resisting coats have the obvious function of providing enhanced abrasion resistance and either or both may be omitted if the replicating layer provides sufficient abrasion resistance in and of itself. Color coats are generally printed on. Generally at least two color coats are necessary if a suitable wood grain or simulated wood grain pattern is to be provided and often three color coats may suitably be utilized for the purpose of providing an attractive and suitable simulated wood grain pattern; however, for providing other patterns which are not simulated wood grain patterns, it may in many instances be suitable to provide only a single color coat or to provide sufficient coloring material in the replicating layer so that no individual color coat is necessary. In some instances, in fact, if no color is desired in the surface finish, no coloring material at all need be incorporated. The purpose of the adherence layer is to promote or improve adherence of the laminar assembly to a substrate, and an adherence coat need be provided only if the adherence is otherwise unsatisfactory. 
     In Table I, the presence of an X in a column indicates that a coating or layer is present in the example heading the column, and the absence of an X indicates the absence of a corresponding layer. 
     
                       TABLE I______________________________________     ExampleCoat:       1     2     3   4   5   6   7   8   9______________________________________B primer    X     X     X   X   X   XD release   X     X     X   X       X           XF abrasion  XG abrasion  XH color     X     X     X   X   X   X   X   X   XI color     X     X     X   X   X   X   X   XJ adherence X     X______________________________________ 
    
     Examples 1 to 8 are suitable for providing two-color patterns, if the color coats are printed, which may be simulated wood-grain patterns, simulated leather patterns and the like. 
     
         __________________________________________________________________________Coat B -- Primer Coat, parts by weight            Example            1   2   3   4   5   6__________________________________________________________________________dimethyl formamide      45           45Goodyear &#34;Vitel&#34; soluble            10          5polyester resin, PE 200Union Carbide VAGH vinyl resin                10          5Union Carbide VMCH vinyl resin                   10           10dioxane          45  45      62chloroform       45  45      33tetrahydro furan        45       95  45cure temp., °F.            250 250                   275  250 250 275cure time, seconds            7   7  7    7   7   7thickness, or wt., wet,            4   3  6    8   9   6lbs. per ream__________________________________________________________________________ 
    
     
         Coat C -- Tick Coat, parts by weight (dry thickness 5 to 20 microns)                   ExampleIngredient or Condition 1  2  3  4  5  6  7  8  9  10 11 12 13__________________________________________________________________________American Cyanamid &#34;Beetle&#34; ureaformaldehyde resin, 212-9                   20       10American Cyanamid &#34;Beetle&#34; ureaformaldehyde resin, 220-8                       20 12       12American Cyanamid Melmac,Melamine resin, 243-3      25       18HCl                     1        .5 1           .5          .3Union Carbide VMCH copolymerof 85 to 88% vinyl chloride, 10.8 to 14.2%            13.5                                                    20vinyl acetate and .8 to 1.2% maleic acid -Rohm and Haas at-50thermosetting acrylic         30       12Johns Manville Celitediatomaceous earth      9     11                   10 8  10Monsanto Santocel FRC, fumed silica                      2           3        5           3Union Carbide VAGD vinyl resin copolymerof 89.5 to 91.5% vinyl chloride, 2.0 to 5.3% 11vinyl acetate and 5.2 to 6.5% vinyl alcoholunion Carbide VAGH vinyl resinsame as VAGD vinyl resin except           11       11higher molecular weightaluminum silicate                6  4p-toluene sulfonic acid    2                       1methyl isobutyl ketone                    40 35    13 45 34zylol                   70    59 28.5                               27 85butanol                    40Dow Corning 704 silicone resin                        1  1benzene                    31    55 50    35 40 74.5                                              53 32.5                                                    35 45Bakelite 2774 ERL catalyst                1  1polyurethane, prepolymer                  13 13cure time               1  1  30 2  2  1.5                                     24 4  1  45 20 20 50                   min.                      min.                         min.                            min.                               min.                                  min.                                     hrs.                                        hrs.                                           min.                                              sec.                                                 sec.                                                    sec.                                                       sec.cure temp., °F.  350                      350                         250                            300                               300                                  325                                     120                                        120                                           250                                              245                                                 275                                                    275                                                       240__________________________________________________________________________ 
    
     
         Coat D -- Release Coat, parts by weight,1 to 4 pounds per ream, wet        Example        1    2      3      4______________________________________petroleum wax, C.sub.43 H.sub.88          5                  .5petroleum wax, C.sub.41 H.sub.84                 4montan wax                   7         5ethyl hydroxyethyl                          4cellulosebenzene        95     96               50   48C Cl.sub.4                   93        45methyl ethyl ketone                         48trichloroethylene                 99.5______________________________________ 
    
     
         Coat E -- Replicating Coat, parts by weight        Example        1   2  3   4  5   6   7   8   9   10  11* 12**                                                      13*__________________________________________________________________________Union Carbide VYHH        17  12                4       15  4vinyl resin copolymerof about 13% vinylacetate and about 87%vinyl chloride, mediummolecular weight**Nitrocellulose 1/2 secR.S.                18  13             5           3Methyl methacrylate,medium molecular wt.       20  15  14  12      13  14  20  10Ti O.sub.2                                         17Iron oxide red                                 15          10butanol             55                 28benzene      50  88     29 80      41      85  34      80  80acetone      33     27  58     85  41  55      34  66cure time, seconds        40  40 30  30 27  25  30  10  10  5   7   10  10cure temp, ° F.        180 180               200 200                      205 200 200 225 230 240 220 215 215coating weights, wetpounds/ream  30  40 30  45 10  12  15  30  20  20  20  40  45__________________________________________________________________________  *single uniform color. **clear 
    
     
         Coat F -- Abrasion Coat            Example 1, parts by weight______________________________________Polyethylene, micronized              7Union Carbide vinyl resin VYNS              14medium-high molecular weightcopolymer of 9.5% to 11.5%vinyl acetate and balancevinyl chlorideacetone            50benzene            29cure   5 seconds at 260°F.coating weight, wet: 15 lbs./ream______________________________________ 
    
     
         Coat G -- Abrasion Coat        Example 1, parts by weight______________________________________Methyl methacrylate          10aluminum oxide 8acetone        78cure: 30 seconds at 200°F.coating weight, wet: 45 lbs./ream______________________________________ 
    
     
         Coat H -- First Color Coat, parts by weight(cure at 180°F. to 220°F. for 4 to 20 seconds)     Example         1    2    3    4    5    6    7    8    9**__________________________________________________________________________Methyl methacrylate         10             20             15Vinyl Chloride resin              10                            12Nitrocellulose, 1/2 sec RS        9    12Me methacrylate -Bu methacrylate co-polymer                 21                            16Ti O.sub.2              1.2                 3         16Molybdate orange         .5   1                                  4carbon black  1    .5   1.2  2    .5   .7   1    1    1acetone            88.5 48.6 78   30.5 29.3 81   87   21benzene       88.5                                    21methanol                28        60   58             21coating weights, wet,lbs./ream     *    *    *    *    *    *    *    *    40__________________________________________________________________________  *depends on pattern **single colorCoat I -- Second Color Coat, parts by weight(coating weights depend on pattern, cure at 180°F.to 220°F. for 4 to 20 seconds)       Example       1   2     3      4   5    6   7    8______________________________________Vinyl chloride resin         10    20             8    22Me methacrylate-butylmethacrylate copolymer    10   20           8    22Iron oxide redMolybdate orange         5     10    4    9   4    4   4    4Chrome yellow 5     10    2    1   3    12  3    12TiO.sub.2     1           1    2   1    3   1    3carbon black              1    2   1    1   1    1acetone       79    60         44  83   58benzene                   82                83   58methanol                       22______________________________________