CA2108534A1 - Method for the preparation of three-dimensional printed surfaces/products - Google Patents

Abstract

ABSTRACT

A method is disclosed for the automated and accurate preparation of three-dimensional decorated flocked articles. The method achieves the application of a surface decoration from a colorant composition without smudging, distortion and nonuniformity of the colors so applied. The method may be practiced in an automated fashion with either a screen printing or lithographic printing station disposed in advance of the thermoforming station. The products that are prepared by the method include three-dimensional molded products having continuous decorations thereon, and products having a pattern of lines dissecting the flocked surface into contiguous sectors, and useful for paint-by-number applications.

Description

METHOD FOR THE PREPARATION OF THRæS~ NgIONAL P~INTED
' 8URFACE81PRODUCT8 TECHNICAL FIELD OF THE INVENTION
! 5 The present invention relates generally to the preparation of decorated sheet or web products having a flocked surface, and particularly to the preparation of ~` such products having a three dimensional surface configuration.
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~ BACKGROUND OF THE INVENTION
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The preparation of products having flocked surfaces is generally known, as is the decoration of such surfaces in a variety of fashions. As is known, flocked surfaces present particular difficulties in decoration, inasmuch as the material disposed thereon is frequently of soft texture and fibrous or other diffuse composition that resists successful, commercially acceptable decoration.
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.j For example, known four-color process printing engaging the application of the colors yellow, magenta, cyan and black.has been attempted; however, wlth great difficulty and limited success. The problems encountered comprise the unevenness of the disposition of the ink which resultingly detracts from the faithful reproduction of the printed image. The tendency of the substrate to absorb the ink unevenly has motivated the adoption of a variety of alternative means for decoration, including the hot transfer and like techniques, all as disclosed in s:~ U.S. Patent No. 4,541,340 to Peart et al., U.S. Patent No. 4,687,527 to Higashiguchi, and U.S. Patent No.
~- 5,059,452 to Squires. In each instance, the objective has been to create the desired decorated coating in advance to, in effect, transfer the coating in a fashion ~ which would prevent its discontinuance reception by the i flocked substrate.
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Early efforts to directly print on flocked material are exemplified by U.S. Patent No. 3,751,284 to Lyons et al., where the problems encountered with the decoration of flocked material were addressed by efforts to control the rate of drying of the dye disposed on the flocked surface. Lyons et al. sought to control the unwanted migration of the dye after impregnation, by a controlled drying technique.
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More recently, Albero in U.S. Patent No. 4,233,027 approached the decoration of a flocked material by sequential application of the dye to the base, followed by the application of flock thereover. The concept in Albero was to print and simultaneously apply the flocked material to the substrate. Alternately, U.S. Patent No.
4,314,813 to Masaki took the approach suggested earlier, of preparing a transfer sheet having flock and a heat vaporizable dye disposed therein. In this fashion, the entire unit may be applied to the substrate to attempt to avert some of the difficulties that have been encountered 'j when flocked materials are decorated.
, All of the aforenoted processes are time-consuming and uneconomical, and, moreover, do not result in the preparation of a faithfully decorated flocked substrate.
The difficulties encountered with these processes are i! made worse when it is considered that the substrate for the flocked material is an impervious plastic sheet and that the resulting flocked article is to be formed into a three-dimensional shape. In such latter event, even the faithful *isposition of the printing medium on the ~ flocked surface frequently results in distortion and `,~ corresponding attenuation of the decorative properties of the resulting product when an extended three-dimensional thermal molding process follows the decorating step. In such event, conventional approaches have centered around the disposition of additional dye at the locations where . .

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draw forming or other distention of the underlying sheet i~ will take place during the molding process, so as to attempt to retain the uniformity of color and proportion that is achieved when the flat surface is initially printed.

As a result, and in cummary, the difficulties that have been encountered when flocked surfaces have been decorated, have been the nonuniformity of the image resulting from the uneven absorption of the flocked ~j surface. Also, a lack of repeatability of the dot `~ structure causing a phenomenon known as "moire," and the reduction in the intensity of the color resulting from ~` the wicking tendency of the flocked surface. The aforementioned difficulties are exacerbated as mentioned earlier, when the surface is stretched as occurs when the molding of the substrate takes place. A need, therefore, exists to develop a method which overcomes the aforenoted ~;: difficulties, and it is to this objective that the present application is directed.

SUMMARY OF THE INVENTION

A method i8 disclosed which facilitates the preparation of decorated articles that are capable of thermoforming ` to three-dimensional shape while retaining faithfully the image on the flat sheet prior to such forming operation.
Particularly, the method comprises the following steps:
A) Applying a quantity of a flocked material to a flat surface comprising a continuous plastic web or sheet;
`~ B) Passing said web through a printing station and applying to the flocked surface of said web, a coating of a colorant composition;
C) Treating the printed flocked surface of said web to dry said colorant composition coating, , ~."
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D) Indexing the web treated in accordance with step C into a forming die and molding said web to form said three-dimensional product; and ` E) Discharging the formed three-dimensional object 5 and indexing said three-dimensional object away from said mold.
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In a first embodiment of the invention, the substrate bearing the flocked surface is prepared into individual 10 sheets that are indexed into or manually placed in a printing station, where alignment for printing is accomplished by means, for example, of edge guides and a front gripper edge, provided at the station. In the ~ instance where a continuous web containing the flocked Y 15 material is prepared, such web is passed through a . printing station in register with a marker or dot that has been preapplied to the workpiece for alignment at the thermoforming section following thereafter. In both instances the printing operation is performed in 20 register.
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The coated web or printed substrate i~ then passed ~ through a heating station to dry the ink. In the P instance where the ink is applied by screen printing, the .` 25 ink may be air dried. After the ink is dried, the substrate enters the mold section and is placed in alignment for thermoforming of the three-dimensional shape o~ the final article. The automated process described with respect to the continuous web includes the 30 provision of an electric eye sensor disposed within the mold or die, that associates and aligns with the marker or dot described earlier.
, ' Of the printing methods and corresponding apparatus ~ 3S useful in the present invention, screen printing and - lithographic printing are preferred.

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The present method is capable of preparing products having a variety of decorations, including continuous multicolored indicia and line-indicia patterns forming ` borders that may be useful for the preparation of products such as paint-by-number surfaces. In each instance, the pattern disposed on the flocked substrate is faithfully received and displayed even after thermoforming is complete. Color intensity is uniform and the dimensions of the imprinted pattern are undistorted.

The substrate of the present invention is preferably a relatively rigid polyolefin material such as styrene, to - which is applied a conventional flock such as cotton.
The colorant composition is preferably a printing ink suitable for either screen printing or lithographic printing operations, and may in a particular embodiment, compri e a vinyl-based composition containing a diazo , dye.
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Accordingly, it is a principal object of the present invention to provide a method for the>preparation of three-dimensional products having a decorated flocked surface, where the decoration is faithfully and uniformly ~1 ~
disposed in the finally formed article.

~,l It i6 a further ob~ect of the present invention to provide a method as aforesaid which may be operated in an automated fashion with economy of processing.
It is a yet further object of the present invention to provide a method as aforesaid for the preparation of ` thrae-dimensional articles having full continuous surface decoration.
It i8 a still further object of the present invention to provide a method as aforesaid which facilitates the . . .

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preparation of articles having a predetermined spaced pattern thereon for use for a paint-by-number product.
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Other objects and advantages will become apparent to those skilled in the art from a review of the ensuing detailed description which proceeds with reference to the ~' following illustrative drawings.
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~` BRIEF DESCRIPTION OF THE DRAWINGS

FIGURE 1 is a schematic plan view sequentially illustrating the various steps of the present method;
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FIGURE 2 is a schematic perspective view illustrating a ~ 15 fully decorated article prepared in accordance with the r~. present invention;
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FIGURE 3 is a schematic perspective view illustrating a typical paint-by-number product prepared in accordance ~, 20 with the present invention.

DETAILED DESCRIPTION
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r As described above, the present invention relates in its `` 25 primary aspect to a method for the preparation of three-,` dimensional decorated articles. Specifically, the decorated articles prepared by the present invention are those that may be suitable for the faithful reproduction ~' of full process continuous indicia, such as illustrated 30 schematically in Figure 2, as well as patterned three-dimensional articles for use, for example, in paint-by-number sets, as illustrated schematically in Figure 3.
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The advantage of the present invention is the ability to 35 prepare such articles with faithful reproduction of the intended pattern, without inconsistencies eithex in the - intensity or coloration of the indicia or the uniformity, :

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crispness or accuracy of the intended pattern so disposed.
., The method of the invention is intended to cover the preparation of decorated three-dimensional articles from pre-cut sheets of the flock-coated substrate, or from a continuous web of the same. For the most part both workpieces are processed substantially identically, and accordingly the terms "web" and "sheet" as used herein - 10 should be considered equivalent unless stated otherwise. .~
More particularly, the present invention is based upon a method which comprises:
A) Applying a quantity of a flocked material to a flat surface comprising a continuous plastic web;
B) Passing said web through a printing station and applying to the flocked surface of said web, a coating of a colorant composition;
C) Treating the printed flocked surface of said web to dry said colorant composition coating;
- D) Indexing the web treated in accordance with step C into a forming die and moldins said web to form ~ said three-dimensional product; and i E) Discharging the formed three-dimensional object and indexing said three-dimensional object away from said mold.
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As described earlier, the three-dimensional decorated flocked article is prepared from a resin base or isubstrate, to which has been applied a flocked layer which is to be decorated and to serve as the outer surface of the final three-dimensional article. The surface decoration may be applied by either a screen printing or lithographic printing technique. In a preferred embodiment, the flocked surface of the substrate web or sheet may be coated with the colorant composition or printing ink directly after the . .:

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application of flock to the substrate. Thus, either the individually formed and pre-cut flock-coated sheet or the continuous web of flocked material is indexed to the printing station. In the former instance, the sheet may be hand carried and placed in the printing station. The specific techniques of screen printing and offset ' lithography are well-known, and further detail regarding q~!~ their performance in the present instance need not be ~ presented herein.
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A variety of resin materials are suitable for use in the preparation of substrates in accordance with the present invention. Thus, among the organic resinous materials ' contemplated, a variety of thermoplastic and - 15 thermosetting matarials may be utilized, including substituted and unsubstituted vinyl polymers such as polyvinyl alcohol, polyvinyl acetate, polyvinyl chloride, ;`; polyvinyl fluoride; polyolefins, such as styrene homo and ~; copolymers; polyesters, such as polyethylene terephthalate; polycarbonates, including acrylic resins, ~i acrylic acid esters, their alkyl- and aryl-substituted homologs such as acrylonitrile-butadi~ne-styrene resins;
and o~hers. Naturally, the foregoing materials are exemplary only and are recited for purposes of ~,~ 25 illustration and not limitation. Particularly suitable , resins comprise styrene, and its polymers and copolymers.
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The colorant composition may be prepared with a suitable pigment or dye for use in the printing or coating of ~` 30 flocked surfaces. Suitable dyes useful in the ink ~ composition may include dyestuffs or mixture of dyestuffs '"! which sublime or vaporize or otherwise convert to a `~ mobile phase at a temperature on the order of about 140C
~-i at atmospheric pressure. Dyestuffs with sublimation temperatures below 140C can also be used, but are not as `~3 suitable because of their tendency to resublime if ` exposed to extended heat in further processing. Suitable .' :

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dyestuffs can include any of the recognized classes of disperse dyestuffs, such as the nitroso, nitro, monoazo, diazo, triazo, polyazo, stilbene, carotenoid, diphenylmethane, triarylmethane, xanthene, acridine, quinoline, methine, thiazole, indamine, indophenol, azine, oxazine, thiazine, sulphur, lactone, aminoketone, hydroxyketone, anthraquinone, indigoid, phthalocyanine, and quinonaphthalone dyes, such as are commercially available or are described in, for example, the third edition of the Colour Index which was published in 1971.

Such dyestuffs are normally the commercially available forms containing considerable amounts of dispersing agents and/or other diluents, but the corresponding pure dyestuffs (i.e., free from dispersing agents and/or diluents) can also be used. Commercially available disperse dyes include the "Foron" dyes from Sandoz Colors & Chemicals, the "Samaron" dyes from American Hoechst, the "Americron" dyes from American Dye & Color Co., the "Artisil" dyes from Sandoz, as well as certain "Nitrofast" oil soluble dyes from Sandoz. As with the resin materials suitable for the preparation of the substrate or web, the foregoing list of materials is merely exemplary and not limitative.
The flock may be applied to the resin substrate by a ` variety of means, including both a direct application of flock to the substrate followed by the application of heat, or alternately, by the initial disposition to the substrate cf a suitable adhesive, followed by the application thereto of the flock coating. A particularly ;
suitable flock material for use in the present invention is cotton, due to its acceptance of the printing ink and any later applied paint or ink, in the instance where the final product is to be used with a paint-by number kit.
Naturally other flock materials may be used when the properties of the final product permit, and accordingly, .

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21~8~34 the invention includes the use of rayon, nylon, acrylic and polyester flock material within its scope. The exact length of the fibers comprising the flock may naturally vary, with representative lengths extending from about 0.3 to about 5.0 millimeters or more, with specific lengths chosen to suit the particular final product. The fineness of the fibers may likewise vary, with ranges on the order of up to about 5.0 deniers as exemplary.
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10 The flock is applied to the substrate in a variety of well-known techniques, including the application to the substrate of a suitable adhesive composition, followed by the disposition by electrostatic or other means of the flock material. Suitable adhesive compositions may vary, 15 with hot melt adhesives being exemplary. Examples of hot melt adhesives comprise resins such as polyethylene, ~ polyamides, ethylene-vinyl acetate copolymers, polyvinylx chloride and polyesters. Other adhesives may be employed~` `and the invention is not limited to the use of the 20 adhesives listed above.

he substrate bearing the flock coating thereon is decorated by the application of a suitable ink. A
variety of ink compositions are useful in both screen 25 printing and offset lithography. Representative compositions contain dyes selected from the known diazo dye family, and may be selected from the materials recited earlier herein. Naturally, the invention is not limited to a particular dye material but contemplates 30 within its scope all dyes and printing inks capabla of faithful application to flocked surfaces. Likewise, the specific colorant compositions may be modified by the application thereto of thickeners, humectants and other additives that modify the physical and/or chemical 35 properties of the dye to facilitate the curing and hardening of the dye in contact with the flock to promote ~1 the formation of a stable printed image.

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The present invention will be better understood from reference to Figure 1, comprising a schematic depiction of the practice thereof. Although Figure 1 specifically depicts continuous operation from a web, it is to be understood that this depiction is applicable to the processing of pre-cut sheets to the extent that the sequence of operations is presented.
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Referring now to Figure 1, the substrate having the flock applied thereto may be prepared as a web, and as illustrated is disposed on a payout reel 2 from which an indefinite length of substrate 4 is taken. Alternately, and as stated earlier, substrate 4 may be prepared into individual sheets, not illustrated herein, that have been precut to correspond in size to the area of the final ` three-dimensional article.
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Substrate 4 is first passed into a suitable printing station 6 which may, in one embodiment, comprise a screen ~. 20 printing apparatus. In the instance where substrate 4 is - a precut sheet, it may be manually placed in station 6, ;~ whereas a continuous web as illustrated would be ; automatically indexed into position. Station 6 as ~i schematically shown may comprise a screen printer where a quantity of ink in emulsion form is disposed across a flexible screen and then applied by a reciprocating squeegee, not shown, to the flocked surface that is ' indexed into position therein. In the instance of a' lithographic printer assembly, the desired image is transferred from a printing blanket to the surface in question in a reciprocating fashion. In the instance `~` where the image in question is multicolored, the application of the respective colors may be conducted by the sequential disposition of four primary colors in what is known as "four color process" printing or screening.
The product as prepared will have a continuous, uniform ., ~
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indicia disposed thereon, as illustrated schematically in Figure 2.

In the instance where the surface to be decorated is to receive a line pattern defining in outline a series of ~ predetermined boxes or other shapes, such pattern is ,à disposed in similar fashion, generally in a single color, by either of the aforementioned printing apparatus. A
schematic illustration of a product so prepared is shown ' 10 in Figure 3 herein.

After the substrate 4 is decorated at station 6, it is indexed to a drying station 8, that as schematically illustrated comprises a heater. The method of the invention contemplates that drying may take place without ~` a heater and in air, in which event station 8 would comprise a drying rack. When present, a heater is set to a predetermined temperature to achieve the uniform drying of the printed indicia without causing undue ~p 20 volatilization or other degradation of the printed image.
-~ The exact temperature and residence time of the substrate in the heater will, of course, vary, depending upon the nature of the ink composition used, and the present invention is not limited to a specific such time or temperature parameter.
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Alternately, the colorant composition may be capable of drying or curing by the application of radiation energy, such as actinic radiation. A particular colorant composition would comprise a vinyl-based-resin composition containing a diazo dye that is sensitive to such radiation and undergoes crosslinking and curing on exposure thereto. In such event, station 8 may comprise a radiation source such as an actinic light or like emitting device. The coated substrate 4 is then passed under the radiation source and is held thereunder for a period of time sufficient to achieve the complete curing . - - .
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of the colorant composition. Generally, residence times on the order of up to about 20 seconds are sufficient, although the exact parameters may vary within the skill of the art.
The coated and dried substrate 4 is next indexed into a suitable thermoforming mold 10 where the predetermined three-dimensional shape of the final article is applied thereto. Thermoforming mold 10 in typical fashion comprises a pair of opposed heated dies such as at 12 and 14, that are brought together to permanently impart the shape of the final article 16 to substrate 4. The temperature and residence time within mold 10 is, again, variable within the skill of the art and will consequently depend upon the composition and thickness of the substrate and the printed indicia disposed thereon.
For example, suitable temperatures would range to within 5C of the softening point of the substrate, with a residence time in mold of approximately 1-2 seconds. The mold 10 may contain means, not shown, for the cooling of the formed article 16 so as to prevent distortion and to assure retention of the molded shape ~hen article 16 leaves the mold.
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After leaving mold 10, article 16 may be indexed to a further station for continued processing. In the instance where the substrate 4 is a continuous web, the formed article 16 may be indexed to a cutting station such as at 18, to sever it from the remainder of substrate 4. The article 16 may be dropped into a bin ~, for transfer to a packing or other station, or may, as illustrated, be placed on a conveyor 20 for transfer to a packing, inspecting or other like station.
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As indicated earlier, the present method is suitable for the application of a variety of indicia to flock-coated surfaces, and particularly surfaces coated with cotton ~ -... ~ .

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flock. In a first embodiment, illustrated schematically in Figure 2 and described earlier herein, the coated article 16 possesses a continuous indicia, such as a picture which is notable in the faithful reproduction thereof and the retention of its intensity, uniformity and accuracy of depiction even in the areas where the ! substrate 4 has been distended by the forming operation.
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A similar accuracy and uniformity is achieved in the instance where a single color pattern is disposed on the ~'1 ~ flocked surface of the article 16, as illustrated `~ schematically in Figure 3. In this instance, a product suitable for use as a three-dimensional paint-by-number `- surface is prepared with lines that retain uniformity of -- 15 color and position despite the application of the thermoforming process after printing operation.
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This invention may be embodied in other forms or carried out in other ways without departing from the spirit or essential characteristics thereof. The present disclosure is therefore to be considered as in all respects illustrative and not restriative, the scope of ~ the invention being indicated by the appended Claims, and -~ all changes which come within the meaning and range of equivalency are intended to be embraced therein.
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Claims (20)

1. A method for the preparation of a three-dimensional decorated flocked plastic product, comprising:
A) Applying a quantity of a flocked material to a flat surface comprising a continuous plastic web;
B) Passing said web through a printing station and applying to the flocked surface of said web, a coating of a colorant composition;
C) Treating the printed flocked surface of said web to dry said colorant composition coating;
D) Indexing the web treated in accordance with step C into a forming die and molding said web to form said three-dimensional product; and E) Discharging the formed three-dimensional object and indexing said three-dimensional object away from said mold.

2. The method of Claim 1 wherein said web is printed by a screen printing operation.

3. The method of Claim 1 wherein said web is printed by a lithographic printing process.

4. The method of Claim 1 wherein said colorant composition is applied in an automated manner.

5. The method of Claim 1 wherein said colorant composition comprises a printing ink.

6. The method of Claim 5 wherein said printing ink contains a dye selected from the group consisting of nitroso dyes, nitro dyes, monoazo dyes, diazo dyes, triazo dyes, polyazo dyes, stilbene dyes, carotenoid dyes, diphenylmethane, triarylmethane, xanthene, acridine dyes, quinoline dyes, methine dyes, thiazole dyes, indamine dyes, indophenol dyes, azine dyes, oxazine dyes, thiazine dyes, sulphur dyes, lactone dyes, aminoketone dyes, hydroxyketone dyes, anthraquinone dyes, indigoid dyes, phthalocyanine dyes, and quinonaphthalone dyes.

7. The method of Claim 6 wherein said printing ink contains a diazo dye and is radiation curable.

8. The method of Claim 7 wherein said colorant composition is prepared as an emulsion.

9. The method of Claim 1 wherein said plastic web is prepared from a resin selected from the group consisting of thermoplastic and thermosetting resin materials.

10. The method of Claim 9 wherein said resinous materials are selected from the group consisting of substituted and unsubstituted vinyl polymers; polyesters;
polyolefins; polycarbonates and mixtures thereof.

11. The method of Claim 10 wherein said resin comprises styrene.

12. The method of Claim 1 wherein said flock is prepared from a material selected from the group consisting of cotton, rayon, nylon, acrylic materials and polyester.

13. The method of Claim 12 wherein said flock is prepared from cotton.

14. The method of Claim 1 wherein said printed flocked surface is treated in Step C) by exposure to air to dry said colorant composition.

15. The method of Claim 1 wherein said printed flocked surface is treated in Step C) by exposure to heat to dry said colorant composition.

16. The method of Claim 1 wherein said flocked surface is treated in Step C) by exposure to actinic radiation to cure said colorant composition.

17. A three-dimensional decorated plastic product having a flocked outer surface, prepared by the method of Claim 1.

18. The three-dimensional product of Claim 17 wherein said flocked surface is provided with a multicolored continuous decoration.

19. The three-dimensional product of Claim 17 wherein said flocked surface is provided with a predetermined pattern of lines dividing said flocked surface into a plurality of contiguous, uncoated sectors.

20. The three-dimensional product of Claim 19 wherein said product is useful for paint-by-number play kits.