US3445551A - Pearlescent,phosphorescent balls and methods for making the same - Google Patents

Description

. May 20, 1969 D. H. GRIFFIN 3,445,551 PEARLESCENT PHOSPHORESCENT BALLS AND METHO FOR MAKING THE SAME Filed May 20, 1966 AWE/V702, flaw/41.0 6/Z/FF/N United States Patent 3,445,551 PEARLESCENT, PHOSPHORESCENT BALLS AND METHODS FOR MAKING THE SAME Donald H. Griflin, Jamestown, N.C., assignor to The Fli- Back Company, Inc., High Point, N.C., a corporation of North Carolina Filed May 20, 1966, Ser. No. 551,587 Int. Cl. C09k 1/12; B28b 1/28 US. Cl. 264-21 6 Claims ABSTRACT OF THE DISCLOSURE This application relates to toy articles and methods for making the same and relates more particularly to the production of a novel ball having a pearlescent appearance and exhibiting phosphorescent properties.

Pearlescence is a quality which is quite desirable from an aesthetic viewpoint and is generally effected in a plastic article by incorporation of fish scales or various other such lamallae which are preferably oriented so that their major faces extend substantially parallel to the surface of the plastic article. Use of certain of such prior art materials may cause toxicity problems if the final article is intended as a toy or the like. Moreover, the manufacturing techniques attendant to the production of pearlescent appearance according to prior art teachings are generally unduly time consuming or complicated whereby such procedures are commercially unattractive.

Certain substances emit a glow after having been illuminated by visible or ultra-violet rays, a property known as phosphorescence. A number of difficulties arise when one attempts to provide toy articles with phosphorescent qualities, particularly with respect to the toxicity which may result from the use of certain prior art phosphorescent materials. In general, the non-toxic phosphorescent pigments have caused various technical problems in the manufacturing operation, particularly with respect to the appearance of the final article. Thus, the toy industry has either avoided the production of phosphorescent articles in their entirety because of the toxicity problems, or compromised and settled for an article having either a less desirable aesthetic appearance or significantly diminished phosphorescent properties.

It is a primary object of the instant invention to provide for the production of toy articles, specifically balls, which are non-toxic and which have an attractive pearlescent appearance while exhibiting a high level of phosphorescence.

An important objective of this invention is the provision of a method whereby a pearlescent, phosphorescent ball can be produced in a novel and efficient manner with relatively inexpensive materials and simple and expenditious manufacturing techniques.

Yet a further object of this invention is to provide for the production of phosphorescent balls having a pearlescent surface and utilizing substantially any flexible plastic material incorporating non-toxic, phosphorescent pigment particles of a type which, although well known in the prior art, have not generally been utilized in such toy articles because of manufacturing difliculties with prior art techniques.

Other and further objects reside in the specific materials utilized in the composition and quantitative ratios thereof as well as the particular manipulative steps of the method of this invention.

Still other objects will in part be obvious and in part be pointed out as the description of the invention proceeds and as shown in the accompanying drawing wherein:

FIGURE 1 is a perspective view of an intermediate product of the instant invention in the form of a hollow, cast ball of reduced diameter, a split mold being shown schematically in broken lines to illustrate the ordinary manufacturing procedure for the production of this intermediate product; and

FIGURE 2 shows the final product of this invention in the form of an expanded, hollow ball having a pearlescent appearance, a needle being illustrated in broken lines operatively engaged with the ball to expand the same to its final diameter.

Like reference characters refer to like parts throughout the several views of the drawing.

According to the basic concepts of the instant invention it has been discovered that a ball can be produced having both a pearlescent appearance and good phosphersecent qualities by initially intermixing a flexible plastic material with well known non-toxic phosphorescent pigment particles, casting the mixture into an intermediate product in the form of a hollow ball of a diameter smaller than the desired diameter of the final product, and then expanding the intermediate product to increase the diameter at least approximately 1% times to the ultimate dimensions of the final product. The intermediate product has a glossy surface in contrast to the pearlescent appearance of the final product which only appears after there has been a diameter increase of approximately P/ times the original dimensions. Surprisingly, initial casting of the plastic mixture into a ball of the final dimensionss does not provide the desired pearlescent surface on the product. Thus, only by forming an intermediate product according to the instant inventive concepts, followed by expansion by high pressure air or the like can a ball having the desired properties be realized.

Although an increase in diameter of at least 1.5 times will produce a pearlescent surface, greater expansion results in an even more attractive pearlescent appearance whereby an increase of 2.5 times or more is preferred. The amount of expansion is only limited by the flexibility of the plastic material since it is obvious that the ball must not be ruptured during expansion and that the final product must have suflicient strength to accommodate the ordinary wear and tear it will receive in use.

Numerous plastic materials can form the basis for the casting mixture utilized to make the ball of this invention, but polyvinyl chloride plastisols are preferred since they are well accepted materials for the production of toys. Of course, dry-blend powdered polyvinyl chlorides, various polyolefins such as polyethylene or polypropylene powders and other such materials can readily be substituted for the preferred plastisol. In fact, the specific type of plastic material is not important so long as it is sufliciently flexible to be expanded according to the technique of this invention. Thus, the term plastic is intended to include the various elastomeric materials having suitable attributes for use in the formulation of a pearlescent, phosphorescent ball according to this invention. However, from a practical standpoint, vinyl resins, particularly the plastisols, and the polyolefins are easier to handle and provide most satisfactory functional properties.

The phosphorescent pigments utilized in the casting mixture can be selected from a relatively wide variety of well known non-toxic materials which provide the desired characteristics. For example, non-toxic, phosphorescent particles of zinc sulfide, calcium sulfide, strontium sulfide, and cadmium sulfide are well known as are various mixtures of such materials such as zinc sulfide-cadmium sulfide, calcium sulfide-strontium sulfide and the like. These materials are generally commercially sieved through a 200 mesh screen and a significant percentage of the particles are sufficiently large to have caused great difficulty with prior art techniques. In contrast, with the procedures of this invention, such materials have been found to work exceptionally well.

The phosphorescent pigment may be incorporated into the plastic mixture in an amount of from approximately 1 to approximately 20 percent by weight although from the standpoint of economy as well as intensity of the phosphorescent effect and aesthetic appearance of the pearlescent surface, a level of approximately 4 percent phosphorescent pigment particles has been found most satisfactory. Of course, other conventional processing materials such as plasticizers, stabilizers and the like can be included in the plastic mixture in their ordinary quantitative ratios.

It should be understood that reference herein to phosphorescent pigment particles is not intended to include other decorative materials frequently incorporated into plastic articles of this type such as plastic granules or colored chips utilized to achieve a marbleized effect, but incapable of providing phosphorescent properties to the final product.

When utilizing a liquid material such as a plastisol, the phosphorescent pigment particles are incorporated by a simple stir-in method whereas with dry-blend vinyls, powdered olefins and the like, the pigment can be used to coat the resin surface by tumbling the mixture prior to the casting operation.

Any suitable well known process may be adapted to the method of this invention for the formation of the intermediate products, the common well known techniques of rotational casting or slush casting being quite satisfactory.

Referring now to the drawing, the intermediate product is designated generally by the reference numeral and comprises a hollow ball which has a glossy surface and results from casting a plastic mixture incorporating non-toxic, phosphorescent pigment particles as explained in more detail hereinabove and hereinafter. A split mold is shown in broken lines at 12 and :14 in FIGURE 1 merely to illustrate the type of apparatus in which the intermediate product 10 is produced. It will 'be understood that the mold halves 12, 14 can form part of a conventional spider arrangement for simultaneously producing multiple products in rotational casting apparatus or the like.

The intermediate product 10 is expanded by air under pressure to the final product shown in FIGURE 2 at 15, portions of a needle 16 being illustrated in broken lines in FIGURE 2 as a means for expanding the intermediate product to its ultimate dimensions.

As set forth hereinabove, the pearlescent appearance of the final product 15, illustratively shown by the stippling in FIGURE 2, does not appear until the intermediate product 10 has been increased at least approximately 1 /2 times its original diameter, and preferably at least 2 /2 times. The final product 15, in addition to having a highly attractive pearlescent surface, exhibits phosphorescent properties so that, after exposure to light, the product will glow in the dark.

Although it is believed that the instant inventive concept can be understood from the previous disclosure, the following Examples are given merely as illustrative:

4 Example I A polyvinyl chloride plastisol for rotational or slush casting will generally have the following ingredients:

(A) P.V.C. Resin-dispersion grade, percent; or adulterated with less expensive grades of resin such as blending, extrusion or calendering grades, the resin used at the 100 phr. and the blending grades substituted up to 50 percent of this 100 phr.:

(B) Ester type primary plasticizers and hydrocarbon type secondary plasticizers used to achieve the rheological, hardness, permanence and temperature service properties desired, in the range of 30-120 phr. levels; and

(C) Metallic stabilizers employed to give the compound initial and long term heat and light stability, used in aphr. range of 05-10.

Specifically, the following formulation produces a highly satisfactory pearlescent, phosphorescent ball when processed according to this invention:

phr. P.V.C. resin-dispersion grade 100 Di-octyl-phthalate 50 Butyl-benzyl phthalate l0 Di-Z-ethyl-hexyl-adipate 20 Epoxidized soya oil 5 Barium-cadmium-zinc stabilizer 3 Phosphorescent pigment, zinc slufide (4% weight) 7.5

The above mixture, formed by a simple stir-in technique, is rotationally or slush cast to form an intermediate product with a diameter of 4 inches which has a glossy surface. Expansion of the intermediate product by high pressure air to a diameter of 10 inches modifies the surface characteristics to produce an aesthetically attractive pearlescent appearance while retaining the phosphorescent properties of the pigment particles. Intermediate products of smaller and larger diameter expanded 1 /2 or more times have similar functional characteristics.

Example II The formulation of Example I can be modified by substituting 100 phr. P.V.C. resin, dry blending grade with similar results.

Also, the phosphorescent zinc sulfide pigment particles of the formulation of Example I can be replaced by phosphorescent calcium sulfide, strontium sulfide, cadmium sulfide or mixtures of these various materials without in any way detracting from the final product.

Example III A pearlescent, phosphorescent ball can also be produced utilizing micro-pulverized polyethylene or polypropylene resin powder at 100 phr. dry blended by tumbling with 1-20 phr., preferably 4 phr. of the phosphorescent pigment particles, processed according to the technique of Example I.

It will now be seen that there is herein provided a pearlescent, phosphorescent ball and methods of making the same which satisfies all of the objectives of the instant invention, and others, including many advantages of great practical utility and commercial importance.

Since many embodiments may be made of the instant inventive concepts, and since many modifications may be made of the embodiments hereinbefore shown and described, it is to be understood that all matter herein is to be interpreted merely as illustrative and not in a limitmg sense.

Accordingly, what is claimed is:

1. A method of making a pearlescent, phosphorescent toy article comprising:

(a) preparing a mixture of a flexible plastic material and a non-toxic phosphorescent pigment including approximately 1 to 20 percent by weight of said pigment based on the weight of said plastic material;

(b) casting said mixture into a hollow ball of an original diameter smaller than the final diameter of the said article; and

(c) expanding said ball to increase said original diameter at least approximately 1 /2 times to said final diameter.

2. The method defined in claim 1 wherein said mixture includes approximately 4 percent by weight of said pigment based on the weight of said plastic material.

3. The method defined in claim 1 wherein said ball is expanded to increase said original diameter at least approximately 2% times to said final diameter.

4. The method defined in claim 1 wherein said plastic material is a polyvinyl chloride plastisol and said mixture is prepared by stirring said pigment into said plastisol prior to casting.

5. The method defined in claim 1 wherein said plastic material is a powdered, dry blend and said mixture is prepared by tumbling said pigment with said plastic material prior to casting.

6. The method defined in claim 1 wherein said pigment is selected from the group consisting of phosphorescent zinc sulfide, calcium sulfide, strontium sulfide, cadmium sulfide and mixtures of the same.

References Cited UNITED STATES PATENTS 2,084,526 6/1937 Grenier 264-21 2,525,965 10/1950 Smith.

3,079,644 3/1963 Molitor et a1. 264-302 3,151,196 9/1964 Tipton 264-302 3,184,524 5/1965 Whiteford 264-320 JULIUS FROME, Primary Examiner.

T. MORRIS, Assistant Examiner.

US. Cl. X.R.

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