IE45757B1 - Method for making decorative emblems - Google Patents

Description

Decorative plaques and emblems (herein generically called emblems) are widely used throughout a number of industries. In the past a coloured vitreous frit was flowed into a bronze substrate and fired at 1250°F. The glass-like vitreous enamel served to beautify 5 the product and protect the decorative emblem from weathering should the plaque or emblem be exposed to the environment. Today plastics are primarily used for producing such plaques and emblems.

For example, in Loew (U.S. patent 3,554,062) there is disa closed a process of injection moulding ^decorative Mylar (Mylar is a registered Trade Mark) facing sheet over a vinyl plastics body. The emblem is coated with a layer of protective varnish on the outer surface of the facing sheet. Other moulding processes, such as compression moulding (either one or two shot), are also well known in the art.

See for instance, U.S. Patents 2,244,565; 2,931,119; 3,075,249; and 3,114,597.

Likewise, polyurethane moulding compositions are also well known in the art. Thus, U.S. patents 3,337,476; 3,391,101; and 3,393,243 disclose polyurethane compositions. Patent No. 3,391,101, then, states that the compounds disclosed therein may be poured into the mould as a liquid (Col.1, lines 49-50); although, this is actually in the context of sealing a pipe rather than producing a moulded product. None of these patents disclose casting polyurethane upon a substrate to produce a decorative emblem. - 2 45757 It is an object of this invention to provide an improved method of making decorative emblems by casting on decorative substrates a specially compounded polyurethane composition which cures to a clear (possibly tinted) hard plastics material resembling and suitable as a substitute for vitreous enamel.

The invention consists in a method of making decorative emblems comprising each of (a) providing a series of decorative substrates,/Said substrates having a top and a bottom surface and having sharply defined peripheral sides which intersect said top surface, or retaining walls defining a cavity within said retaining walls, onto which substrate a polyurethane composition is to be cast, (b) mixing a polyether polyol component with a di-isocyanate component to form a polyurethane composition, (c) casting said polyurethane composition on the top surface of said substrates, either in sufficient quantity to form a positive meniscus without flowing over said sharply defined peripheral sides, or in sufficient quantity to form a positive or negative meniscus without overflowing the cavities, (d) curing said cast polyurethane to provide a hard plastics material resembling vitreous enamel while maintaining said substrates flat and horizontal.

The substrate may be a decorated cavity of metal or plastics material into which the glass-like plastics material is cast. When a metal cavity is used as the substrate, it is preferably of aluminium or chrome. Chrome parts are desirably thoroughly cleaned and primed before casting, whereas aluminium parts are desirably anodized and - 3 45757 primed before casting. The cavity may also be made of moulded plastics material. Decorative surfaces are also formed on the part by moulding, painting, printing or coating prior to having the glasslike plastics material cast into the cavity.

The inventipn also consists in a method of making decorative emblems comprising a base which carries a decorative foil shape onto which a clear, hard plastics composition is cast, comprising: (a) providing a series of flat decorative foil shapes each having a top and bottom surface and having sharply defined peripheral sides which intersect with said top surface, and having an adhesive coated on its bottom surface, (b) holding said series of foil shapes flat and horizontal on a support surface and free from surrounding side walls, (c) casting a measured amount of said plastics composition in liquid form directly onto the top surface of each of said foil shapes so that it flows to said sharply defined peripheral sides and forms a positive meniscus without flowing over said sharply defined peripheral sides, (d) curing said plastics composition while maintaining said foil shapes flat and horizontal, whereby said cured plastics composition produces a clear, hard plastics layer providing a lens effect to the top surface of said foil shapes onto which it has been cast, and (e) utilising said adhesive coated bottom surface of said foil shapes to adhere said foil shapes with the hardened plastics composition cast thereon onto a base.

The foil shapes (discs, oval or otherwise) may comprise a - 4 4 5 7 5 7 metal foil, of from 0.001 to 0.010 inch thick. Colors, information or other decoration m4y be applied to the foil by lithography, silk normally screening or other methods^ used to decorate metal. The foil shapes may be embossed or raised in selected areas. The foil can also be a plastics material such as Mylar, polyethylene, polyethylene terephthalate, and may be plain or embossed.

The cast plastics material, when cured, gives a lens effect to each individual, decorative shape. The preferred plastics composition is a polyurethane composition although it is possible to use other castable plastics materials capable of forming a clear, hard plastics layer, resembling vitreous enamel, having a meniscus and giving a lens effect.

The polyurethane composition is preferably produced by the reaction of polypropylene glycols with an aliphatic di-isocyanate.

To facilitate the application of the chemicals in the product, the glycols and di-isocyanate are compounds into an easily handled twopart product. The two parts are then mixed in proper proportion, degassed to remove air bubbles and then poured into the substrate cavities to form a clear, hard plastics material.

Preferred embodiments of the invention will now be described with reference to the accompanying drawings, in which:Figure 1 is a perspective view showing the mixing tanks and dispensing nozzle; Figure 2 is a cross-sectional view of an emblem with a plastics insert cast into the decorated cavity of a metal or plastics - 5 45757 substrate. The volume of the cast plastics material is larger than that of the cavity with rounded sides into which it is cast; Figure 3 is a cross-sectional view of an emblem with a plastics insert cast onto the decorated cavity of a metal or plastics substrate; Figure 4 is a cross-sectional view of a cast plastics insert on a two-angled surface; Figure 5 'is a cross-sectional view of a plastics insert cast into a substrate\which is not level; Figure 6 ,is a cross-sectional view of a cast plastics emblem having a volume smaller than the volume of the cavity into which it is cast; Figure 7 is a cross-sectional view of a cast plastics emblem having a volume greater than the volume of the cavity into which it is cast; Figure 8 is a partial perspective view of a casting operation, Figure 9 is a cross-sectional view of a disc with plastics material cast thereon, and Figure 10 is a view similar to Figure 9 and showing what happens if the disc has a rounded edge.

Figure 11 is a cross-sectional view of a cast plastics insert having a volume in excess of what the cavity will retain; / Figure 12 is a cross-sectional view of a cast plastics emblem having a metal base with a decorated injection moulded plastics insert; - 6 4S757 Figure 13 is a cross-sectional view of spill-over cast; Figure 14 is a cross-sectional view of a cast without spillage; Figure 15 is a front view of an automobile emblem; Figure 16 is a cross-sectional view of the emblem of Figure 15 showing one method of casting the emblem; and Figure 17 is a cross-sectional view of the emblem of Figure 15 showing an alternate method of casting the emblem.

One of the features of this invention is the formation of a clear, hard plastics material for use as a substitute for vitreous enamel. The material is a polyurethane composition. It involves basically a reaction between an isocyanate material and a polyether polyol to form a urethane polymer. This is a fairly simple addition process which, when extended to difunctional or polyfunctional reagents, provides a direct route to polymers. The hydrogen on the nitrogen atom of the urethane group is capable of reacting with more isocyanate to form allophanates which provide the means of introducing branching or cross-linking in the polyurethanes. The reaction provides a bond high in thermal stability and resistant to hydrolysis.

In the instant process, a polyurethane compound is produced by the reaction of polypropylene glycols with an aliphatic di-isocyanate. To facilitate the application of the chemicals in production, the glycols and di-isocyanate are compounded into an easily handled twopart product.

The first part, Part A, which is the polyol component of the two-part system, is made by mixing a difunctional, trifunctional - 7 and/or tetrafunctional polypropylene glycol, adding suitable catalyst, surface active agents and light and heat stabilizing agents.

The component, Part A, is prepared from polypropylene glycols which have two, three, four or more hydroxyl groups per molecule or any combination of these. The polyols are combined with a catalyst, ultraviolet absorber, antioxidant and surfaceactive agent. After combinatio'n, the product is heated to 90°C under twenty-nine inches of vacuum for one hour, cooled to room temperature and packaged. A typical formula is as follows: Part A Parts by weight Polypropylene glycol (triol) TP-440 77.57 Polypropylene glycol (diol) P-245 19.39 Catalyst (DBTDL) 1.00 Antioxidant (Naugard P) 1.00 Ultra-violet absorber (UV-317) 1.00 Surface active agent SF-69 .04 100.00 The amount of the catalyst (DBTDL) can range from 0.10 to 2.00; the amount of the antioxidant can vary from 0.25 to 2.00; the amount of the ultra-violet absorber (UV-317) can vary from 0.25 to 2.00 and the amount of the surface active agent SF-69 can vary from 0.01 to 0.10.

The molecular weight of the triol can vary from 300 to 3000 and the molecular weight of the diol can vary from 400 to 2000.

The other part, Part B, which is the di-isocyanate component of the two-part system, is prepared by reacting an aliphatic di-isocyanate with a polyol, di, tri or tetrafunctional in nature to form a quasi prepolymer. The purpose of the prepolymer is to - 8 4S7S7 control the viscosity and ultimate reaction rate of Part A with the di-isocyanate Part B. The dry polyol, di, tri, and tetrafunctional is mixed with the di-isocyanate and heated slowly to 90°C for one hour under twenty-nine inches of vacuum and then cooled to room temperature, drawn off and packaged. A typical formula is as foi1ows: Part B Parts by weight Polypropylene glycol (triol) TP-440 15.00 Hylene W (di-isocyanate) 85.00 lOu.oo (Hylene is a trademark) The molecular weight of the triol can vary from 400 to 2000 and the Hylene has a large range.

Tetrols can be substituted for triol, in either Part A or Part B. Any suitable diol can be used.

The catalyst can be any heavy metal compound of the group of tin, lead, zinc, mercury, bismuth, cadmium, antimony, etc. A suitable antioxidant yielding a colorless compound can be used. Ultraviolet absorbers soluble in polyol and clear in the final product are suitable. The surface active agent is a silicone compound and can be one of many compounds.

Hylene W is an aliphatic di-isocyanate available from E.I. duPont de Nemours & Co. Substitutes for it are hexamethylene di-isocyanate, xylene di-isocyanate, cyclohexyl di-isocyanate or any light stable (saturated) di-isocyanate. - 9 45757 After Part A and Part B are prepared as stated, the two parts are then mixed in the proper proportion, degassed to remove air bubbles and poured onto an emblem surface to form a clear, hard plastics material. The cure can be accelerated by the addition of heat.

The polypropylene glycol (diol) and the polypropylene glycol (triol) are commonly available on the market, and for example, can be those manufactured by the BASF Wyandotte Corporation as P-410 and TP-440, respectively. P-410 is listed by BASF Wyandotte as a Pluracol (Trademark) polyether diol having a molecular weight of 425 (calculated from hydroxyl number), an OH No. of 265, a viscosity at 25°C of 75 cps, and a pH of 6.5. TP-440 is listed by Wyandotte as a polyether triol having a molecular weight of 425 (calculated from hydroxyl number), an OH No. of 398, a viscosity at °C of 600 cps and a pH of 6.5.

The two parts, Part A and Part B, are mixed in the following proportions by weight: Part A 44.50 Part B 55.50 100.00 This is the preferred proportion, although the proportions can vary from 40-50% for Part A and from 60-50% for Part B.

The resulting urethane compound is 100 percent solid and clear and is stable under sunlight and weathering. The preparation of a hard, glass-like, colorless polyurethane by the use of triols and tetrols modified with diols for elasticity is believed novel - 10 45757 as is the use of an antioxidant to help stabilize a polyurethane.

To produce the compound and cast it into a decorative cavity, several steps are involved which are enumerated below.

Initially, the chrome parts that the plastics material will be cast into the make emblems are thoroughly cleaned, which involves soaking in a hot water bath incorporating a suitable cleaning agent, rinsing, a cathodic clean, an anodic clean (both being Oakite [Registered Trademark] 190 and hot water at 180°F), rinsing steps, a chromic dip in air agitated chromic acid and water, rinse and soak steps and a final air drying step.

The aluminium parts are vapor sprayed, soaked clean, rinsed, deoxidized, rinsed, bright dipped, rinsed, anodized, rinsed and dried. The result of this is that the anodic film thickness shall be between 0.00030 and 0.00040 inches.

All parts are then primed with a suitable primer within eight hours from the time cleaned (chrome parts) or anodized (aluminium parts). The thickness shall be between 0.00020 to 0.00040 inches and the coverage is such that it extends at least 0,1000 inches beyond the contact point of the plastics cast.

All parts then requiring paint are painted within one week from the priming. Prior to painting, the parts are baked at a minimum of 200°F for sixty minutes. The parts are then spray painted. The painted parts are then sent to the casting department where they are cast within one week from the date of painting.

Referring to Figure 1, there is shown the casting apparatus designated generally as 10. A vacuum line 12 is connected via lines 14 and 16 to storage - degassing tanks 22 and 24, respectively. - 11 ZiS757 A pair of bail valves 18 and 20 are inserted in lines 14 and 16 to insure against any air going back into the tanks. Supply lines 30 and 26, having ball valves 32 and 28 therein, supply component Part A and Par-B to tanks 22 and 24, respectively. The A and B materials can be stirred for the purpose of degassing.

The degassed material then flows down pipes 34, 36 through ball valves 38, 40 through filters 42, 44 through metering devices and into mixing and casting head 46 which is of a standard design.

Located beneath the casting head is a moving conveyor 48 with which the casting head 46 is timed. The conveyor carries the ornaments or pieces to be cast, such as 50. When a piece comes under the casting head, the belt stops. A predetermined amount of the plastics material is cast and then the conveyor moves the next piece into position. The cast pieces are moved forward into baking areas. The pieces are then cooled and unloaded.

The cast material has the property of hardness without brittleness and withstands heavy abuse from strong detergents and from impact. It can withstand rigid water and humidity tests, salt and acid tests, hot and cold temperature tests, and gas tests. Thus, it is an excellent filler material for painted decorative parts.

The cured material has a shore D hardness of 80-85 and a specific gravity of 1.06. The component part A has a viscosity of 375 cps, although the cps (centipoise) can vary from 300 to 1000, RPM RVP Brookfield #4 spindle at 25°C; 390 cps (300 to 1000 cps is the range) 20 RPM RVP Brookfield #4 spindle at 25°C. Component Part B's viscosity is 500 cps 2 RPM RVP Brookfield #4 spindle at 25°C, 20 RPM RVP Brookfield #4 spindle at 25°C. Component Part A - 12 4S7S7 has a specific gravity of 1.05 and component Part B has a specific gravity of 1.07.

Again the mixing ratio, by weight, is approximately 45 parts of Part A and 55 parts of Part B. The mixing ratio, by volume, is one part of Part A to one part of Part B. The volume tolerance should not vary from plus or minus one-half part. The gel time for the mixed parts is approximately two minutes and ten seconds, although the range is from two to seven minutes at 150°F. If a high crown or bulge on the top of the cast emblem is desired, it can be cured at room temperature up to 200°F for a longer period.

The decorative part must be free of moisture, grease, dust and other foreign matter. The part must be perfectly level and must be relatively flat. The component parts are mixed carefully and thoroughly in the mixing and casting head, the material should be mixed without entrapping air. If air bubbles do develop, the material should immediately be degassed. This is done by drawing a good vacuum on the material, releasing the vacuum, drawing another vacuum and releasing the vacuum again. The compound should be mixed.degassed and cast within the aforementioned gel time.

The plastics material is clear and, when cast, increases the clarity of the paint on the cast part and enhances the details of the embossed and debossed areas. The surface of the cast material has a slight crown which assists the edge of the cast plastics material to blend smoothly to the part, whether the latter be metal, aluminium or plastics material. The material can be tinted with various colors, but excellent results are obtained with the clear cast which contrasts with the decorative, metal and paint. - 13 Referring now to Figures 2 and 3, there are shown alternative constructions for the cast emblems of ornaments. Figure 2 shows an emblem having a metal or plastics base structure 70. The base structure 70 having base 68 is designed with retaining walls 60, a rounded top 66 on the retaining walls, and cavity 62 with raised and depressed areas such as 63 that can be decorated by hot stamping, painting, or printing. After the details of the cavity are decorated the cast plastics material is poured or cast into cavity 62. The composition and casting technique is utilized by casting an amount of the plastics composition greater than the volume of the area defined by the cavity if a plane were laid atop rounded top portions 66, that is, the casting will form a positive meniscus, the angle Z, defining a tangent to the point where the edge of the plastics ends on the portion 66 can be less than 90° but not less than 30°. The cast plastics material can have any thickness but usually is about five thirty-seconds of an inch thick. It can algo be pigmented to make a multi-color emblem.

Referring now to Figure 3, there is shown an alternate construction for an emblem. A metal or plastics frame 80 is provided having a cavity with a flat base 84. A metal foil insert 88 of from .001 to .010 inch is bonded or secured by an adhesive 86 to the base 84 of frame 80. Colours or information are applied to the foil by litho-graphy, silk screening or other methods normally used to decorate metal. Images are embossed or raised in selected areas.

It should be noted that the foil can also be a plastics material such as Mylar1,1 polyethylene, polyethylene tetephthalate and either be - 14 45757 plain or embossed.

After the foil 88 is secured into the frame, a clear plastics coating 90 is cast op top of the foil insert which adheres both to the foil and the side walls 82 of the frame 80. This differs from the usual practice inasmuch as it eliminates the necessity of painting or hot stamping the metal frame itself.

Referring now to Figure 4, there is shown a member 90 having angled surfaces 91 and 92 and canted dike walls 93 and 94. The cast has a planar upper surface 96 which tapers down at the edges 97, 98 towards the top of the dikes 93 and 94. Thus, one can cast on a nonpi anar surface.

Figure 5 shown as example of casting on a non-horizontal surface. A member 99 is positioned at an angle C (shown exaggerated) from the horizontal and has a planar cavity surface 101 and dike walls 100 and 105 perpendicular to the surface 101. The cast material will bulge as at 102 and meet the top of dike wall 100 in a positive meniscus. The surface of the plastics material then goes through a reverse curve as at 103 and tapers up at 104 to meet the top of dike wall 105 in a negative meniscus.

Figures 6 and 7 show examples of a negative and positive meniscus, respectively. In Figure 6, a hollow member 106 having a flat horizontal planar surface 108 and perpendicular dike walls (such as 107) is cast with an amount of plastics material whose volume is less than that of the cavity. The result is a flat surface 109 whose periphery is slanted upwards as at 110 to form a negative meniscus.

The composition, due to its formula and surface tension, will tend - 15 4575? (as shown) to rise up the dike wails.

In Figure 7, a hollow member 111 having a planar bottom 113 and dike walls 112 is filled with an amount of plastics material whose volume is in excess of the volume of the cavity. The material is generally planar as at 114 and slopes down as at 115 to intersect the top of dike walls 112. It will not spill over as long as surface 114 is not too high above the top of the dike walls, and as long as the top of the retaining wall 112 is clearly defined with a radius of .002to .010at the top.

Figure 11 illustrates what can happen if too much of the composition is cast and the dike wall is too wide and sharp at 125. A hollow member 123 has a flat planar bottom surface 124 and perpendicular dike wall 125. Material 125' is cast therein and when the height X exceeds a certain ampunt, the material runs over the top of the dike wall 125 as at 126.

In another aspect of the present invention, a measured amount of the composition in liquid form is cast directly onto the top surface of foil shapes, for example by the technique shown in Figure 8, wherein a vacuum chuck 139 holds a sheet of release paper 140 thereon through a vacuum being created underneath the sheet. Chuck 139 has a plurality of holes therein (not shown) through which the vacuum is applied. A series of metallic foil discs 141, 142, etc. are placed on the sheet. The discs have been lithographed or silk screened on their top' surface and have an adhesive on the bottom surface thereof. T-he operator or automatic machine utilizes dispensing head 143 with nozzle 145 and supply line 144 to dispense a - 16 45757 measured amount of the composition atop and onto each disc. The dispensing head 143 regulates the amount. The discs are similar to the disc 127 of Figure 9 insofar as each has a sharply defined peripheral side which intersects with the top planar surface. The cast composition is cured and cooled and the ornamental design on the top of the disc is enhanced by the lens effect created by the cast composition.

It is important to keep the foil material shapes flat and horizontal during the casting and curing process. The shape can be a plastics foil, a metal foil, paper foil or “Mylar foil. A design can be embossed therein prior to casting. In the technique shown in Figure 11, the discs are spaced to avoid any static charge attraction between the discs as the material is cast thereupon.

Figure 9 shows a flat metal foil disc 127 having perpendicular peripheral sides 128, 130. The cast plastics material is flat on top and slopes down to form a positive meniscus. D represents the diameter of the disc, Y the height of the plastics material and W the height of the disc. Test results of a disc where Z is 0.020 inch are as follows D in inches Y in inches 0.25 .030 0.50 .075 0.75 .100 1.00 .125 1.50 .125 In the table, Y represents the maximum height that the material may achieve without flowing over the periphery of the disc. Applications of more liquid on disc 127 than denoted in the Y column results in liquid overflows due to a break in surface tension. Overflow results in thinner - 17 45757 film sections. The compound was applied at a disc temperature of 72°F.

When a free body of liquid, such as the compound described herein, is at rest on a solid, the degree of flatness on the top surface of the liquid is a function of the condition at the edges where the liquid contacts the solid. If the wettability characteristics of the liquid are such that liquid does not wet the solid, it indicates that the liquid particles attract each other more than the solid particles attract the liquid particles. That is, the cohesive forces of the liquid are greater than the adhesive forces of the solid and liquid. This condition of the liquid is called the meniscus. The meniscus formed by the instant compound when it is applied to a flat surface results in a lens effect. The lens effect is exploited by applying the compound to a painted or decorated surface to increase the aesthetic values related to depth, clarity and brilliance. These characteristics are used to produce the foil-backed inserts.

Figure 10 shows what happens when the condition of the disc edge is not perpendicular. A disc 133 has a perpendicular edge 134 and a rounded edge 135. The material 136 will stay on the disc at 137 adjacent the perpendicular edge 134 and runs over the rounded edge 135 as at 138.

The cured cast material has the property of hardness without brittleness and withstands heavy abuse from strong detergents and impact. It can withstand rigid water and humidity tests, salt and acid tests, hot and cold temperature tests, and gas tests. Thus, it is an excellent filler material for painted decorative parts. - 18 45757 The cured material has a shore D hardness of 80-85 and a specific gravity of 1.06. The component Part A has a viscosity of 375 cps, although the cps (centipoise) can vary from 300 to 1000, RPM RVP Brookfield #4 spindle at 25°C; 390 cps (300 to 1000 cps is the range) 20 RPM RVP Brookfield #4 spindle at 25°C. Component Part B's viscosity is 500 cps 2 RPM RVP Brookfield #4 spindle at 25°C, 20 RPM RVP Brookfield #4 spindle at 25°C. Component Part A has a specific gravity of 1.05 and component Part B has a specific gravity of 1.07.

( Again the mixing ratio, by weight, is approximately 45 parts of Part A and 55 parts of Part B. The mixing ratio, by volume, is one part of Part A to ope part of Part B. The volume tolerance should not vary from plus or minus one-half part. The gel time for the mixed parts is approximately two minutes and ten seconds, although the range is from two to seven minutes at 150°F. If a high crown or bulge on the top of the cast emblem is desired, it can be cured at room temperature up to 200°F for a longer period.

The decorative part must be free of moisture, grease, dust and other foreign matter. The part must be perfectly level and must be relatively flat. The component parts are mixed carefully and thoroughly in the mixing and casting head. The material should be mixed without entrapping air. If air bubbles do develop, the material should immediately be degassed. This is done by drawing a good vacuum on the material, releasing the vacuum, drawing another vacuum and releasing the vacuum again. The compound should be mixed degassed and cast within the aforementioned gel time. - 19 The plastics material is clear and, when cast, increases the clarity of the paint on the foil shape and enhances the details and debossed of the embossed; areas. The surface of the cast material has a slight crown which assists the edge of the cast plastics material to blend smoothly to the foil shape, whether the latter be metal, aluminium or plastics. The material can be tinted with various colours, but excellent results are obtained with the clear cast v/hich contrasts with the decorative metal and paint. The decorative foil shape with the hardened plastics composition cast thereon is finally adhered to a desired base by its adhesive coated bottom surface.

Figure 12 shov/s the design of yet another emblem that can be made by utilizing the composition and casting technique of this invention. A plastics or metallic base 148 having a hollow cavity with a flat bottom surface and a perpendicular peripheral wall is used. An injection moulded plastics insert 150 is decorated by painting, printing, or hot stamping. Then bonded to the base with a suitable adhesive 149. The cast plastics material 152 is then poured or cast into the cavity 151 so that the cast plastics seals or protects the decorated surface and locks the insert 150 to the frame sidewalls of cavity 151.

The plastics composition can be cast in an amount that is somewhat greater than the volume of the area defined by the cavity if a plane were laid atop rounded top portions 151. That is, the casting will form a positive meniscus. The angle (equivalent to angle Z in Figure 2) defining a tangent to the point where the - 20 45757 edge of the plastics ends on the portion 151, can be less than 90° but not less than 30°.

Figures 13 and 14 illustrate the effectiveness of a perpendicular dike wall versus a rounded dike wall.

In Figure 13, a planar base member 153 has a rounded dike 154 with a height X. Plastics material is cast as at 155 and will tend to flow over the top of the dike as at 156 and continues beyond on the other side. Figure 14 shows a planar surface 158 with a dike 159 having a sharply defined radius at the top and perpendicular wall 160 with height T of .060 minimum. The cast composition 161 will mound above the dike and will stop at 162, the top point of dike wall 160. This illustrates how the material will creep over a rounded surface. The same material will stop and mound to form a positive meniscus when it is retained by a sharply defined dike.

Figures 15 to 17 illustrate a typical metal automotive ornament generally designated as 170. It consists of an attachment 171 for mounting the ornament in the hood of a car. Chrome plated portions 172, 173 arc upwardly to surround the centre portion, a support 174 extends upwardly and supports a frame 175 consisting of horizontal members 176, 177 and a pair of arcuate members. The area defined by the frame has a cast insert therein and a series of figures such as 179-181. Figures 16 and 17 show the ornament of Figure 15 in cross-section and illustrate two techniques for forming the insert. Figure 16 shows half of an insert 184 which has been injection moulded, decorated and placed in the position shown. Members 176, 177 have longitudinal members - 21 182, 183, which are L-shaped in cross-section, respectively, which fit into a peripheral recess, the horizontal portions of which are denoted by 185, 186. The inner face 187 of the insert has a series of raised areas 188, 189 and 190 (shown exaggerated) which are embossed, hot stamped, painted, or silk-screened with colours and decorative portions. These raised areas are in the shape of figures 179-181 of Figure 15. Once the insert half 184 is in place, the ornament and insert are positioned horizontally and the other half of the insert is cast in the resulting shallow cavity and allowed to cool and cure. The composition being cast will adhere to the surface 187 of the injection moulded insert and thus will lock the two insert halves together forming the completed insert. Since the cast portions are either clear or slightly coloured, the figures 179-181 will be visible and appear unsupported, thus creating a pleasing aesthetic impression.

Figure 17 illustrates an alternative method of making the ornament of Figure 15. The ornament is laid horizontally atop a casting base 191 which is made of a material to which the cast composition will not adhere. The base fits snugly as at 192, 194, with members 176, 177. Atop the main surface 200 of base 191 are a series of depressions into which are placed decorative figures 196-198, which correspond to figures 179-181 in Figure 15. The composition is then cast atop the base surface 200 which may be treated wjth a release medium to insure against the composition adhering thereto. The material adheres to the inside of members 176, 177, forming a slight negative meniscus, and projections 193, 195. The material is allowed to cure and cool - 22 4S757 and the ornament is then turned over and cast on the other side.

Thus, the insert is locked to the frame 175 and the figures, which can be made of metal or another suitable substance, are embedded therein. Thus, to an observer, the ornaments of Figures 16 and 17 would look alike, although different methods were employed in making each one.

An improved composition and unique casting techniques have resulted in improved products. Because of the surface tension of the composition, the employment thereof in ornaments creates a lens effect, thereby enhancing the aesthetic effect of the ornament.

While various embodiments of the invention have been shown and described, it will be obvious to those of ordinary skill in the art that many changes.and modifications can be implemented without departing from the scope of the appended claims.

Claims (20)

1. A method of making decorative emblems comprising: each of (a) providing a series of decorative substrates,/Said substrates having a top and a bottom surface and having sharply defined peripheral sides which intersect said top surface, or retaining walls defiping a cavity within said retaining walls, onto which substrate a polyurethane composition is to be cast, (b) mixing a polyether polyol component with a diisocyanate component to form a polyurethane composition, (c) casting said polyurethane composition on the top surface of said substrates, either in sufficient quantity to form a positive meniscus without flowing over said sharply defined peripheral sides, or sufficient quantity to form a positive or negative meniscus without overflowing the cavities, (d) curing said cast polyurethane to provide a hard plastics material resembling vitreous enamel while maintaining said substrates flat and horizontal.

2. The method according to claim 1, wherein said polyether polyol component of said polyurethane composition comprises a polyether diol, a polyether triol, a catalyst, an antioxidant, an ultraviolet absorber, and a small amount of surface active agent.

3. The method according to claim 1 or 2, wherein said diisocyanate component of said polyurethane composition comprises an aliphatic di-isocyanate and a polyether triol.

4. The method according to claim 1, 2 or 3, wherein said polyether polyol component consists, in percentages by weight, of - 24 45757 approximately 19% polypropylene diol, 78% polypropylene triol, 1% catalyst, 1% antioxidapt, 1% ultra-violet absorber and .04% surface active agent.

5. The method according to claim 1, 2, 3 or 4, wherein said di-isocyanate component consists of approximately 85% by weight of aliphatic di-isocyanate and 15% by weight of polypropylene triol.

6. The method according to claim 1, 2, 3, 4 or 5, wherein said polyurethane composition comprises 40-50 percent by weight of said polyether polyol component and 60-50 percent by weight of said di-isocyanate component.

7. The method according to claim 1, 2, 3, 4, 5 or 6, wherein said cast polyurethane composition is cured by heating at about 150°F for from two to seven minutes.

8. A method of making decorative emblems comprising a base which carries a decorative foil shape onto which a clear, hard plastics composition is cast, comprising: (a) providing a series of flat decorative foil shapes each having a top and bottom surface and having sharply defined peripheral sides which intersect with said top surface, and having an adhesive coated on its bottom surface. (b) holding said series of foil shapes flat and horizontal on a support and free from surrounding side walls, (c) casting a measured amount of said plastics composition in liquid form directly onto the top surface of each of said foil shapes so that it flows to said sharply defined peripheral sides and forms a positive meniscus without flowing over said sharply defined - 25 peripheral sides, (d) curing said cast plastics composition while maintaining said foil shapes flat and horizontal, whereby said cured plastics composition produces a clear, hard plastics layer providing a lens effect to the top surface of said foil shapes onto which it has been cast, and (e) utilising said adhesive coated bottom surface of said foil shapes to adhere said foil shapes with the hardened plastics composition cast thereon onto a base.

9. The method according to claim 8, wherein said plastics composition is a polyurethane having a polyether polyol component and a di-isocyanate component.

10. · The method according to claim 9, wherein said polyether polyol component of said polyurethane composition comprises a polyether diol, a polyether triol, a catalyst, an antioxidant, and ultra-violet absorber, and a small amount of surface active agent.

11. 'The method according to claim 9 or 10, wherein said di-isocyanate component of said polyurethane composition comprises an aliphatic di-isocyanate and a polyether triol.

12. The method according to claim 9, 10 or 11, wherein said polyether polyol component consists ip percentages by weight of approximately 19% polypropylene diol, 78% polypropylene triol, 1% catalyst, 1% antioxidant, 1% ultra-violet absorber and .04% surface active agent.

13. The method according to claim 9, 10, 11 or 12, wherein said di-isocyanate component consists of approximately 85% by - 26 45757 weight of aliphatic di-isocyanate and 15% by weight of polypropylene triol.

14. The method according to claim 9, 10, 11, 12 or 13, wherein said polyurethane composition comprises 40-50 percent by 5 weight of said polyether polyol component and 60-50 percent by weight of said di-isocyanate component.

15. The method according to any one of claims 9 to 14, wherein said cast polyurethane composition is cured by heating to about 150°F for from two to seven minutes. 10

16. The method according to any one of claims 8 to 15, wherein said decorative foil shapes are discs formed of a foil having an ornamental design thereon.

17. The method according to claim 16, wherein said discs have a diameter of from .25 - 1.50 inch and said plastics composition 15 is cast to a height of from .03 to .125 inch on each of said discs.

18. The method according to claim 16, wherein said discs are approximately one inch in diameter and said plastics composition is cast to a height of no more than .125 inch.

19. A method of casting decorative emblems, substantially 20. As hereinbefore described with reference to Figures 1 - 7 and 11- 17 or Figures 8 - 10 of the accompanying drawings.

20. A decorative emblem when cast by the method in any of claims 1 to 7 or 8 to 18.