Patent Publication Number: US-6214141-B1

Title: Decorative flocking techniques

Description:
FIELD OF THE INVENTION 
     This invention relates generally to flocking, fiber-coatings and the like and, in particular, to methods of applying and modifying flocked surfaces to achieve a decorative effect, particularly with respect to toys such as dolls and other applications. 
     BACKGROUND OF THE INVENTION 
     Flocking has been used for a surprisingly long time to give surfaces a velvet-like texture and appearance. The techniques dates back several decades, and has been used for many years in conjunction with selective application on wallpaper and other surfaces. 
     Typically, an area to be flocked is coated with an adhesive or glue, and the flocking particles, usually in the form of small elongated fibers, are blown onto the surface, where they become attached. When the glue dries, depending upon the length and composition of the fibers, a soft or fuzzy texture and/or appearance will be result. 
     Modernly, flocked surfaces are used in a wide variety of applications, including compartment linings in automobiles and other vehicles, where the affect is not only attractive, but also minimizes vibrational noise due to rattling of compartment contents. It is typical, for example, to use flocking in between-seat consoles, and the like, where cassettes tapes and CDs are stored. Flockings are also commonly added to textile substrates for use in clothing, upholstery covers, and packaging. 
     Other applications of the process have been more limited, since the usual steps to achieve a velvet-like touch and appearance are only suitable to certain types of uses. With respect to toys such as dolls, for example, flocking has been used to simulate hair, but due to limitations in the process, has been relegated to a short, fuzzy presentation, which is predictable if not unappealing. The need remains, therefore, for modifications to the application of flocking so as to achieve a greater range of desired visual and/or textural affects, so as to simulate the feel of natural hair. 
     SUMMARY OF THE INVENTION 
     The present invention resides in a method of flocking a surface, and treating the flocking, so as to achieve a decorative effect. The various steps are suited to toys such as dolls in particular, where the treated flocking may be used to simulate different types of hair and hair styles. 
     Broadly, the method includes the steps of applying an adhesive to a surface to be flocked, directing a group of flocking particles onto the surface, and treating the result using alternative techniques to achieve a desired effect. In one embodiment, the particles are in the form of fibers which “ball up” upon the application of heat, and the outwardly exposed ends of the particles are flame-treated to create a kinky appearance. Nylon fibers are suitable in this case. 
     In an alternative embodiment, an adhesive is applied to the flocking particles attached to the surface, and additional flocking particles are applied to the adhesive-coated fibers. If the length of the additional flocking particles is substantially shorter than the length of the flocking particles of the first group, a shag-type surface appearance is realized. 
     According to yet a further alternative embodiment, air pressure is applied to the particles before the adhesive cures, so that the particles assume a preferred orientation with respect to the surface. Using the doll application once again, this approach achieves a laid-down hair style which is quite stable upon curing of the adhesive. 
     In all cases, two groups of particles having different fiber lengths are preferably directed toward and onto the surface before the adhesive cures so as to fill in gaps following the initial application. Preferably, the first group of flocking particles are electrostatically directed onto the surface, whereas the second group of flocking particles are pneumatically applied. Through the use of variable flock length, fiber type, denier and processing steps according to the invention, a wide range of natural hair styles and other effects may be simulated. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a drawing which illustrates a first embodiment of the invention used to create a kinky hair appearance; and, in particular: 
     FIG. 1A illustrates, from an oblique perspective, a doll having hair produced in this manner; 
     FIG. 1B is a high simplified side view drawing of a first application of flocking fibers; 
     FIG. 1C illustrates how the first application of fibers may be supplemented with a second group of fibers to fill in gaps and provide certain desired textural effects; 
     FIG. 1D shows how, through the use of flame treating, the ends of the fibers will ball up through the application of heat to create a desired affect; 
     FIG. 2 illustrates an alternative embodiment of the invention used to create a shag-type look/appearance and, more particularly: 
     FIG. 2A illustrates how this shag-type appearance is applicable to doll hair; 
     FIG. 2B illustrates in simplified fashion a first application of relatively long flocking fibers to a surface; 
     FIG. 2C illustrates how these initial fibers are subsequently coated with an adhesive; 
     FIG. 2D shows how a second application of preferably shorter flocking particles are directed onto the adhesive first group of particles to create this desired affect; 
     FIG. 3 illustrates yet a further alternative of the embodiment of the invention wherein a longer hairstyle or other affect may be produced and, in particular, FIG. 3A illustrates how this embodiment might appear in a typical application; 
     FIG. 3B illustrates how longer flocking fibers are applied according to this aspect of the invention; 
     FIG. 3C illustrates the fibers may be caused to lie down through the use of a pneumatic spray. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Now making reference to the figures, the drawings show embodiments of the invention, and endeavor to illustrate important steps in carrying out different aspects of the method to achieve desired affects. In particular, the drawings associated with FIG. 1 depict an embodiment of the invention used to create a flocked surface having a kinky appearance suitable for dolls having that hairstyle, FIG. 2 illustrates the appearance and steps used to achieve a shag-type look, and FIG. 3 illustrates how a pneumatic jet of air may be used to style flocking fibers for a more layed-down look. Although these descriptions utilize the example of doll hair, the invention is not limited in this respect. Indeed, the steps of each embodiment of the method may be applied to a wide variety of flat and curved surfaces to achieve a range of effects depending upon the type of adhesive and length and composition of the flocking particles. For example, in addition to human hair, simulated animal hair is also possible, including horse hair, dog and cat fur, etc. 
     FIG. 1A illustrates a doll head having a hair style exhibiting what might be considered a short nappy look according to the invention. The area to be flocked is first masked off, if desired, and a suitable glue or adhesive applied, preferably in spray form. The flocking particles, typically in fiber form, are then electrostatically and/or pneumatically applied. Use of an electrostatic application is more conducive to an on-end adhering of the fibers, as shown in FIG.  1 B. Electrostatic charge levels on the order of 50-80 kVa are suitable for use in conjunction with a pneumatic feed rate of about 30 and an air pressure of from 10 to 60 psi using a K-Omega pneumatic flocking machine. 
     Although the base material itself is not electrically conductive, certain adhesives exhibit a slight electrical conductivity such that when a electrode is placed on the surface a slight (negative) charge is achieved. The charge on the flocking particles tends to build up at the tip of the fiber, and since the fibers are cylindrical in nature they become dipoles, causing them to turn around in the air and lodge on-end in the adhesive-coated surface. Having treated surface areas which are easily accessed through electrostatic application, so gaps may remain. If the glue remains tacky, the part is delivered to a pneumatic station where a second group of particles, preferably variable in terms of length and denier, are blown in to essentially fill in the gaps. Since the fibers that were applied electrostatically are embedded perpendicularly with respect to the surface, the additional, pneumatically applied particles oriented themselves along side the first grouping of fibers, as shown in FIG.  1 C. 
     Using a water-based adhesive, the product is cured in an oven at 180° F. for approximately 20 minutes, then allowed to cool down. As illustrated in FIG. 1D, the fibers are flame treated to lightly singe the exposed ends of the fibers, causing them to curl down or “ball-up.” A commercially available nylon fiber having 3 to 24 denier thickness and 0.040-inch to 0.250-inch length has been found suitable for doll-hair applications. Masking may also be used to avoid heat-treating areas that may be damaged by the flame. 
     Now turning to FIG. 2, FIG. 2A illustrates how a longer, kinkier or shag-type appearance may be achieved using the invention. The starting fibers are on the order of 10 times longer than those used in the process of FIG.  1 . Again, a first group of particles are preferably applied electrostatically, followed by a pneumatic gap-filling application preferably using smaller fibers (not shown). 
     The adhesive is cured, but then a second application of adhesive is used to at least partially coat the already attached fibers as shown in FIG.  2 C. Following this, a second (or third) group of particles, preferably shorter fibers, are attached pneumatically, as shown in FIG.  2 D. Masking may be used where appropriate to limit adhesive and/or particle application. The result is a Christmas-tree appearance, with the shorter fibers glued to the longer fibers. It has been found that shorter fibers on the order of 0.20-0.30 inches in length at 1.8 denier work well with base fibers of 3.0 denier. 
     Now turning to FIG. 3, FIG. 3A illustrates from an oblique perspective a method of achieving rather densely packed fine straight hairs which actually lie down onto the surface as opposed to being perpendicular. According to this aspect of the invention, an initial group of particle fibers is electrostatically applied with a supplemental pneumatic application being used to fill in the gaps. While the adhesive has not yet cured, a gentle air spray of, for example, 5 to 20 psi, is directed at the crown of the head, in the case of a doll product, or in any other desired orientation, causing the fibers to lie down or assume some other form relative to the surface. The result is then cured and cleaned by blowing out loose fibers. Conveniently, the final product may be covered and/or shipped in a plastic bag which is preferably wrapped tightly around the head of the doll so that the matted fibers cure with a desired orientation.