WO1995011794A1

WO1995011794A1 - Method of printing molded articles

Info

Publication number: WO1995011794A1
Application number: PCT/US1994/010924
Authority: WO
Inventors: Louis S. Moren
Original assignee: Minnesota Mining And Manufacturing Company
Priority date: 1993-10-29
Filing date: 1994-09-27
Publication date: 1995-05-04
Also published as: AU8072494A

Abstract

The invention relates to a method for providing indicia (20, 20') on a surface of a molded article (35, 35'). The indicia (20, 20') is provided either directly on a molding surface (12), or on an indicia transfer medium (14) that is placed on the molding surface. A moldable composition (30) contacts the indicia (20, 20') and the molding surface (12), and solidifies to form the article (35, 35'). The indicia (20, 20') transfers to the article (35, 35'), and becomes partially embedded within the article, which increases the durability of the indicia.

Description

METHOD OF PRINTING MOLDED ARTICLES

TECHNICAL FIELD

The invention relates to a method of printing molded articles, such as molded abrasive wheels.

BACKGROUND OF THE INVENTION

Molded abrasive wheels have wide applicability in the abrasives field, where they are used for such things as the deburring and finishing of metal, the removal of excess molded material or paint, wood sanding, glass grinding and polishing, surface preparation prior to the application of paint or plating, and the application of decorative finishes to a workpiece. Molded abrasive wheels may comprise materials having abrasive particles dispersed throughout and adhered within a crosslinked polyurethane binder matrix (described in greater detail in, for example, United States Patent Number 4,933,373 (Moren) ) , and typically resemble flat discs or pucks. The abrasive wheel may be attached to and rotated by, for example, a drill, such that the peripheral edge of the spinning abrasive wheel can contact a surface to abrade material therefrom. Greater or lesser material removal can be effected by increasing or decreasing pressure on the abrasive wheel, respectively.

Each type of abrasive wheel has certain abrasive characteristics, and information regarding these characteristics is typically provided by printed indicia (such as alphanumeric characters, or a colored area) that is applied to at least one face of the abrasive wheel. The operator need only inspect the printed indicia when she wishes to determine whether a particular abrasive wheel is appropriate for a given application.

The printed indicia is typically applied to the abrasive wheel by one of two methods. One method is to print the indicia directly onto the surface of the abrasive wheel by, for example, letterpress, gravure, silk screen, rubber stamp, or pad printing. These operations are well known in the art and are described in the literature, including Donatas Satas, Plastics Finishing and Decoration 156-251 (Van Nostrand Reinhold 1986) . Although direct printing is an effective method of displaying indicia on an abrasive wheel, it requires a separate processing step to position the abrasive wheel and to print the indicia on the surface of the wheel. Furthermore, because the printing lies atop the surface of the abrasive wheel, the ink may be rubbed or scratched off inadvertently, rendering the indicia less easily identified. Thus, printing indicia on the surface of an abrasive wheel may be undesirable in some instances.

A second method of supplying indicia on an abrasive wheel is to print the indicia on a label, and to apply the label to the abrasive wheel. The label may be made of paper, fabric, or film, for example, and is typically bonded to the surface of the abrasive wheel by an adhesive. However, the labeling process requires several processing steps - printing and positioning the labels, positioning the abrasive wheel, and adhering a label to each abrasive wheel - and may be undesirable for that reason. Furthermore, the labels lie atop the surface of the abrasive wheel, where they are susceptible to unintentional defacement or removal. Also, during use of the abrasive wheel, the label may interfere with the abrasive action because of shredding of the label material, or because the label adhesive may be deposited on the workpiece. The cost of the labels also adds to the total cost of the abrasive wheel, and thus the labeling method of indicia display also can be undesirable. In view of the disadvantages of conventional methods of providing indicia on molded abrasive wheels, it is desirable to provide an inexpensive method of supplying durable indicia on these and other articles.

SUMMARY OF THE INVENTION

The present invention includes a method for providing indicia on a surface of a molded article. The method comprises the steps of providing a mold having at least one molding surface shaped to form a surface of the article, providing indicia on the molding surface, providing a sufficient quantity of moldable composition to form the article, placing the quantity of moldable composition in contact with the molding surface and the indicia, solidifying the moldable composition to form the article, and transferring the indicia from the molding surface to a surface of the article. The indicia may be provided directly on the molding surface, or may be provided on an indicia transfer medium that is placed on the molding surface. The indicia preferably comprises ink. In one embodiment, the article is a disc-shaped abrasive wheel. Also provided is a molded article, comprising a surface having indicia displayed thereon, with the indicia bonded to and embedded in the surface of the article.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be further explained with reference to the appended Figures, wherein like structure is referred to by like numerals throughout the several views, and wherein:

Figure 1(a) is a sectional view of a mold having indicia provided directly on a molding surface, in accordance with the present invention; Figure 1(b) is a sectional view of a mold having indicia provided on an indicia transfer medium on a molding surface, in accordance with another embodiment of the present invention;

Figure 2 is a sectional view of a mold having a quantity of moldable material within the mold cavity and in contact with the indicia, in accordance with the present invention;

Figure 3 (a) is a sectional view of an article having indicia provided according to the present invention; and

Figure 3 (b) is a sectional view of another article having indicia provided according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The method of the present invention, which will be described in detail below, involves providing indicia on a molding surface of a mold, and placing a quantity of a moldable composition in contact with the molding surface and the indicia. As the moldable composition solidifies to form the article, the indicia transfers from the transfer surface to the article. Thus, the indicia is partially embedded within a surface of the article, which provides indicia that is more durable, and less expensive, than indicia provided by conventional methods.

Although the present invention will be described primarily in the context of providing indicia on a surface of a molded abrasive disc, the method of the present invention is believed to have broad applicability to article molding processes generally. Thus, the article of the present invention could be any molded article on which it is desired to provide indicia, including but not limited to molded consumer goods (such as tires, microwave cookware, and cosmetic containers, for example), sheet members, and other suitable articles. The method of the present invention includes the use of a mold. As shown in Figure 1, mold 10 comprises a ring mold including molding surfaces 12 that are adapted to form an article. As used herein, a "mold" means a tool with at least one molding surface to which a moldable composition may conform. The term "moldable composition" means any material or mixture that can be solidified to form an article, and may include, for example, such compositions as polyurethane, epoxy, polyurea, polypropylene, polyethylene, and polyester. Several illustrative examples of moldable compositions are specifically described in the Examples.

The molding surfaces of the mold may be concave, convex, or any combination thereof, and may comprise such things as endless belts, rollers, and plates. The mold may be a split mold having two or more mold components, which, when assembled, provide molding surfaces 12 adapted to form, for example, a circular abrasive wheel. Alternatively, mold 10 can be an open face mold, or open mold, wherein one or more surfaces of the article (when formed in the mold) are open to the environment and are not in contact with a molding surface during the solidification process. Mold 10 may include one or more inlet ports (not shown) through which the moldable composition may be introduced into the mold to form the article. Multiple inlet ports may be particularly useful for forming relatively large molded articles. Other suitable variations in the molding apparatus and process are intended to be within the scope of the present invention.

In the illustrated embodiment, mold 10 is a ring mold wherein a ring portion 11 is placed on a flat molding surface 13. An indicia transfer medium may be placed between the molding surface 13 and the ring portion 11, as shown in Figure 1(b) and described below.

Indicia 20 is provided on the molding surface of the mold, and thus will be contacted by the moldable composition that is used to form the article. The indicia of the present invention may be alphanumeric printing, a decorative design, a mark identifying the type, price, grade, brand, or manufacturer of the article, a color, or any other desired indicia. Indicia 20 may be provided either directly on the molding surface (by printing on the molding surface, for example) , or on an indicia transfer medium that is placed on the molding surface (a release liner, for example) . In each case, the indicia must be provided in a location where the moldable composition used to form the article can contact the indicia, to enable the indicia to transfer to the article as it is formed.

Figure 1(a) illustrates an embodiment wherein indicia 20 is provided directly on molding surface 12. It should be noted that indicia 20 may be provided on more than one molding surface, although shown on only one molding surface in the illustrated embodiment. It may be desirable to provide a release coating on the molding surface, to facilitate release of the indicia and the moldable composition from the molding surface during and after the molding process. Release coatings include, but are not limited to, polydimethylsiloxane, silane, polyethylene, polypropylene, talc-filled polypropylene, soap, waxes, or poly(tetrafluoroethylene) .

Figure 1(b) illustrates an embodiment wherein indicia 20' is provided on an indicia transfer medium - release liner 14 - which has been placed on molding surface 12 beneath ring portion 11. Release liner 14 may comprise one or more of several different materials, including but not limited to paper, film, or fabric, and may be coated with a release agent such as polydimethylsiloxane, silane, polyethylene, polypropylene, talc-filled polypropylene, soap, waxes, or poly(tetrafluoroethylene) to facilitate release^* of the indicia from the release liner. As a nonlimiting example, the release liner may be constructed of silicone coated kraft paper available from the Daubert Coated Products Company of Westchester, IL, under the designation 2-126KLB-157.

Indicia 20 may be applied to either the molding surface or the indicia transfer medium in any suitable manner. For example, the indicia may be applied to the transfer surface by letterpress, offset, rotogravure, rubber stamp, or silk screen printing. The indicia may comprise ink, a polymer, a metallic film, paint, pigment, or dye. The indicia preferably comprises a material that is known to have a greater affinity for the moldable composition used to mold the article than for the transfer surface, to promote transfer of the indicia to the article. For example, an ink may be selected because it is known to have a greater affinity for a particular polymer used to mold an article than for the molding surfaces. In the case of the moldable composition being a molded abrasive wheel precursor, virtually any ink will suffice so long as the release liner functions as intended.

Ink is the preferred indicia material, and it is also preferred that the ink remain where it is applied (to either the molding surface, or to the indicia transfer medium, as appropriate) , so that the indicia remains sufficiently coherent to permit recognition by an observer. Inks that may be cured by ultraviolet (UV) radiation are believed to be particularly useful, because there is no solvent evolution during the curing process, and because UV curing is relatively quick and inexpensive.

When the indicia has been provided on the molding surface (either directly, or on an indicia transfer medium placed on the molding surface) , the moldable composition 30 used to form the article may be placed in contact with indicia 20', as shown in Figure 2. Although in many embodiments the moldable composition contacts one or several molding surfaces, it is only required that the moldable composition contact the indicia, and thus the moldable composition need not directly contact the molding surfaces. This may occur, for example, when an indicia transfer medium is applied over all of the molding surfaces. Moldable composition 30 is typically a two-part reactive mixture that polymerizes when the two parts are mixed, although other materials, such as other thermoplastic or thermosetting polymers, metals, and ceramics are also contemplated. The temperature, flow rate, and flow path of moldable composition 30 should be controlled so as not to damage the indicia 20 during the molding process.

A metering mechanism (not shown) may be provided to measure the proper amount of moldable composition required to form the article. The moldable composition typically flows over and around the indicia, such that the indicia will be embedded within the article. As that term is used herein, "embedded" means that the indicia contacts the molded article 35 both 1) along the bottom surface of the indicia (shown in Figure 3(a) and 3(b) at 40 and 40', for example), and 2) along the side surfaces of the indicia (shown in Figures 3(a) and 3(b) at 42 and 42', for example). Thus, articles made according to the present invention included indicia embedded within the article 35, whereas articles made according to the prior art include indicia that overlies a surface of the article.

When the proper amount of moldable composition 30 has been placed in contact with the molding surface, the material is solidified, or cured to form the article. Solidification may be facilitated by catalyzing a polymerization reaction by thermal or chemical means, cooling the mold, or by firing or sintering, especially in the case of ceramics. During the solidification process, the indicia transfers to and into a surface of the article, thus becoming embedded within the article. This is in contrast to other conventional methods of applying indicia, wherein the indicia is merely applied onto the surface of the article after formation. Depending on the thickness of the indicia and the properties of the moldable composition, at least part of the thickness of the indicia is typically embedded beneath the top surface of the article, which lends durability to the indicia. When the article has solidified, it may be removed from the mold. In those instances where an indicia transfer medium is used, transfer medium may be peeled away from the article, leaving the indicia embedded within the surface of the article 35. If necessary, the excess material formed at the edges of the article during the molding process (known as "flash") may be trimmed from the article to produce the finished product.

It should be noted that the present invention has been described with respect to providing indicia on a surface of an article. It is also contemplated that indicia may be provided on two or more surfaces of an article (both sides of a circular molded abrasive wheel, for example) , whether or not those surfaces are adjacent each other.

To facilitate a complete understanding of the present invention, the inventive method and articles produced thereby will now be described in the context of the following Examples.

Examples Each of the following Examples is of an abrasive article having printed indicia applied to the article in accordance with the inventive method. In each Example, a ring mold was provided having a cylindrical interior cavity measuring approximately 15.24 cm in diameter and 0.635 cm high (6 inches in diameter,- 0.25 inches high) .

A release liner having printed indicia thereon was placed between a bottom plate and the ring portion of the mold, such that the indicia would be contacted by the moldable composition. An unprinted piece of release liner was placed on the top of the mold, and the mold was closed. The moldable composition, the contents of which are described below in each Example, was poured into the ring mold, and the mold was covered and heated to a temperature of 46° C (11-5° F) .

After 30 minutes, the partially cured abrasive article was removed from the mold. The release liner was stripped from the article surface revealing the transferred printing of the article bottom. The release liner on the top of the article was also removed. The printed abrasive article was placed in an oven and heated to 110° C (230 °F) for 90 minutes to complete the curing process. The specific details and the results of each Example are summarized below. Example One

The release liner was a silicone coated kraft paper of the type available from Daubert Coated Products Inc. of WestChester, Illinois, under the designation Daubert 2-126KLB-157. The indicia was provided on the release liner by silk screening onto the release liner a black silk screen ink of the type available from Color Mix Inc. of Schaumburg, Illinois, under the designation UVP-100.

The moldable composition was made from the following materials:

Component % (wt.) (Description) (Commercial name; Supplier: Location) hydroxyl terminated polybutadiene 8.43

(long-chain diene prepolymer) (Polybd R-45 HT; Elf Atochem North America Functional Polymers Division, Philadelphia, Pennsylvania) poly(ox tetramethylene)diol 2.61

(long-chain saturated prepolymer) (Polymeg 2000; QO Chemicals Inc., West Lafayette, Indiana) diethyltoluene diamine 0.17

(Ethacure 100; Ethyl Corporation, Baton Rouge, Louisiana)

1, 4 butanediol 1.67

(ISP Technologies Inc., for GAF Chemicals, Wayne, New Jersey) deionized water 0.10 pert-butyl peroxy-2-ethylhexanoate 0.78

(cross-linking initiator) (Lupersol PDO; Elf Atochem North America Inc., Fine Chemicals Group, Philadelphia, Pennsylvania) dKC,.^_!!-alkyl)phthalate 1.39 (plasticizer)

(Palatinol 711-P; Chem Central, Lakeville, Minnesota) tetra (2,2 diallyloxymethyl-1-butoxy) titanium di( i-tridecyl) phosphite

0.17

(coupling agent) (KR-55; Kenrich Petrochemicals, Inc., Bayonne, New Jersey) polyalkyleneoxidemethylsiloxane copolymer 0.44 (surfactant) (L-603; Union Carbide Corp., Danbury, Connecticut) mixture of organic salt of tertiary a ine and an organometallic compound in organic solvents 0.05 (urethane catalyst (3:1 ratio))

(Dabco DC-I:Dabco DC-2; Air Products, Allentown, Pennsylvania) polyisocyanate 9.19 (Isonate 143L; Dow Chemical Co., Midland, Michigan) garnet abrasive mineral 75.00

(60 grade, average particle size 0.25 mm) (Barton Mines, North Creek, New York)

A polyol mixture was formed using all of the foregoing components, except the polyisocyanate and the garnet mineral. To this polyol mixture the polyisocyanate and the garnet abrasive were added and dispersed uniformly throughout. The resulting reactive abrasive particle slurry was poured into the cavity of the open mold, and the remainder of the procedure was as described above. The resultant abrasive article, including printed indicia, was satisfactory.

Example Two

The abrasive article printed in accordance with Example Two was made in the same manner as described above with reference to Example One, with the following exceptions. The moldable composition was made from the following materials: Component % (wt.) (Description) (Commercial name; Supplier.- Location) hydroxyl terminated polybutadiene 11.53

(long-chain diene prepolymer)

(Polybd R-45 HT; Elf Atochem, North America Functional Polymers Division, Philadelphia, Pennsylvania) polytetramethylenenoxide-di-p-aminobenzoate 4.28 (long-chain saturated prepolymer) (Polamine 1000; Air Products Inc., Allentown, Pennsylvania) diethyltoluene diamine 0.23

(Ethacure 100; Ethyl Corporation, Baton Rouge, Louisiana) 1, 4 butanediol 0.81

(ISP Technologies Inc., for GAF Chemicals, Wayne, New Jersey) sodium/potassium/aluminosilicate 0.19 (Type 3A molecular sieve)

(UOP, Des Plaines, Illinois) water 0.01 pert-butyl peroxy-2-ethylhexanoate 0.91

(cross-linking initiator)

(Lupersol PDO; Elf Atochem North America Inc.,

Fine Chemicals Group, Philadelphia,

Pennsylvania) butyl stearate 1.37

(Kessco butyl stearate cosmetic; Stepan

Company, Northfield, Illinois) tetra (2,2 diallyloxymethyl-1-butoxy) titanium di(di-tridecyl) phosphite 0.17

(coupling agent)

(KR-55; Kenrich Petrochemicals, Inc., Bayonne, New Jersey) polyalkyleneoxidemethylsiloxane copolymer 0.23 (surfactant)

(L-603; Union Carbide Corp., Danbury, Connecticut) polyisocyanate 5.90

(Isonate 143L; Dow Chemical Co., Midland, Michigan) aluminum oxide mineral 74.36

(50 grade; average particle size 0.297 mm) (Washington Mills, Niagara Falls, New York)

The aluminum oxide and polyisocyanate were added to the polyol mixture of the remaining components (as with the polyisocyanate and the garnet abrasive in Example One) and dispersed uniformly throughout. The remainder of the process was as described in Example One, and the resultant abrasive article, including printed indicia, was satisfactory.

Example Three

The abrasive article made and printed in accordance with Example Three was made in the same manner as described above with reference to Example Two, except that the ink was blue rather than black. The resultant abrasive article included satisfactory printed indicia.

Example Four

The abrasive article made and printed in accordance with Example Four was made in the same manner as described above with reference to Example Two, except that the ink was green rather than black. The resultant abrasive article included satisfactory printed indicia.

Example Five

The abrasive article made and printed in accordance with Example Five was made in the same manner as described above with reference to Example Two, except that the ink was maroon rather than black. The resultant abrasive article included satisfactory printed indicia. Example Six

The abrasive article made and printed in accordance with Example Six was made in the same manner as described above with reference to Example One, with the following exceptions. The moldable composition was made from the following materials:

Component % (wt.)

(Description)

(Commercial name; Supplier.- Location) hydroxyl terminated polybutadiene 12.49

(long-chain diene prepolymer) (Polybd R-45 HT; Elf Atochem, North America Functional Polymers Division, Philadelphia, Pennsylvania) polytetramethylenenoxide-di-p-aminobenzoate 4.64 (long-chain saturated prepolymer) (Polamine 1000; Air Products Inc., Allentown, Pennsylvania) diethyltoluene diamine 0.25

(Ethacure 100; Ethyl Corporation, Baton Rouge,

Louisiana)

1, 4 butanediol 0.88

(ISP Technologies Inc., for GAF Chemicals,

Wayne, New Jersey) sodium/potassium/aluminosilicate 0.21

(Type 3A molecular sieve) (UOP, Des Plaines, Illinois) water 0.01 pert-butyl peroxy-2-ethylhexanoate 0.99

(cross-linking initiator)

(Lupersol PDO; Elf Atochem North America Inc., Fine Chemicals Group, Philadelphia, Pennsylvania) butyl stearate 1.48

(Kessco butyl stearate cosmetic,- Stepan Company, Northfield, Illinois) tetra (2,2 diallyloxymethyl-1-butoxy) titanium di(di-tridecyl) phosphite 0.19

(coupling agent) (KR-55; Kenrich Petrochemicals, Inc., Bayonne, New Jersey) polyalkyleneoxidemethylsiloxane copolymer 0.25

(surfactant)

(L-603; Union Carbide Corp., Danbury,

Connecticut) polyisocyanate 6.39

(Isonate 143L; Dow Chemical Co., Midland,

Michigan) silicon carbide mineral 72.22

(50 grade,- average particle size 0.297 mm) (Minnesota Mining and Manufacturing Company, St. Paul, Minnesota)

The silicon carbide mineral and the polyisocyanate were added to the polyol mixture of the remaining components (as with the polyisocyanate and the garnet abrasive in Example One) and dispersed uniformly throughout. The remainder of the process was as described in Example One, and the resultant abrasive article, including printed indicia, was satisfactory.

Example Seven

The abrasive article made and printed in accordance with Example Seven was made in the same manner as described above with reference to Example One, with the following exceptions. The moldable composition was made from the following materials:

Component % (wt.) (Description) (Commercial name.- Supplier.- Location) hydroxyl terminated polybutadiene 12.15 (long-chain diene prepolymer)

(Polybd R-45 HT; Elf Atochem, North America Functional Polymers Division, Philadelphia, Pennsylvania) polytetramethylenenoxide-di-p-aminobenzoate 4.51 (long-chain saturated prepolymer) (Polamine 1000; Air Products Inc., Allentown, Pennsylvania) diethyltoluene diamine 0.25

(Ethacure 100; Ethyl Corporation, Baton Rouge, Louisiana) 1, 4 butanediol 0.86

(ISP Technologies Inc., for GAF Chemicals, Wayne, New Jersey) sodium/potassium/aluminosilicate 0.20

(Type 3A molecular sieve) (UOP, Des Plaines, Illinois) water 0.01 pert-butyl peroxy-2-ethylhexanoate 0.96

(cross-linking initiator)

(Lupersol PDO; Elf Atochem North America Inc., Fine Chemicals Group, Philadelphia, Pennsylvania) butyl stearate 1.44

(Kessco butyl stearate cosmetic,- Stepan Company, Northfield, Illinois) tetra (2,2 diallyloxymethyl-1-butoxy) titanium di (di-tridecyl) phosphite 0.18

(coupling agent) (KR-55; Kenrich Petrochemicals, Inc., Bayonne, New Jersey) polyalkyleneoxidemethylsiloxane copolymer 0.24 (surfactant) (L-603; Union Carbide Corp., Danbury, Connecticut) polyisocyanate 6.22

(Isonate 143L; Dow Chemical Co., Midland, Michigan) aluminum oxide mineral 72.97

(220 grade; average particle size 0.065 mm) (Washington Mills, Niagara Falls, New York)

The aluminum oxide mineral and the polyisocyanate were added to the polyol mixture of the remaining components (as with the polyisocyanate and the garnet abrasive in Example One) and dispersed uniformly throughout. The remainder of the process was as described in Example One, and the resultant abrasive article, including printed indicia, was satisfactory. Example Eight

The abrasive article made and printed in accordance with Example Eight was made in the same manner as described above with reference to Example Seven, except as follows. The printing on the release liner was provided by lithographic printing instead of silk screening. The amounts of the various components were as follows:

Component % (wt.) (Description) (Commercial name.- Supplier.- Location) hydroxyl terminated polybutadiene 11.71 (long-chain diene prepolymer)

(Polybd R-45 HT,- Elf Atochem, North America Functional Polymers Division, Philadelphia, Pennsylvania) polytetramethylenenoxide-di-p-aminobenzoate 3.31 (long-chain saturated prepolymer) (Polamine 1000; Air Products Inc., Allentown, Pennsylvania) diethyltoluene diamine 0.25

(Ethacure 100; Ethyl Corporation, Baton Rouge, Louisiana)

1, 4 butanediol 1.67 (ISP Technologies Inc., for GAF Chemicals, Wayne, New Jersey) sodium/potassium/aluminosilicate 0.21

(Type 3A molecular sieve) (UOP, Des Plaines, Illinois) water 0.01 pert-butyl peroxy-2-ethylhexanoate 1.02 (cross-linking initiator)

(Lupersol PDO; Elf Atochem North America Inc., Fine Chemicals Group, Philadelphia, Pennsylvania) butyl stearate 1.53

(Kessco butyl stearate cosmetic,- Stepan Company, Northfield, Illinois) tetra (2,2 diallyloxymethyl-l-butoxy) titanium di(di-tridecyl) phosphite 0.04

(coupling agent) (KR-55; Kenrich Petrochemicals, Inc., Bayonne, New Jersey) polyalkyleneoxidemethylsiloxane copolymer 0.26 (surfactant) (L-603; Union Carbide Corp., Danbury, Connecticut) polyisocyanate 8.58

(Isonate 143L; Dow Chemical Co., Midland, Michigan) aluminum oxide mineral 71.43

The remainder of the process was as described in

Example Seven, and the resultant abrasive article, including printed indicia, was satisfactory.

Example Nine

The abrasive article made and printed in accordance with Example Nine was made in the same manner as described above with reference to Example One, with the following exceptions. The release liner was silicon coated kraft paper of the type available from the Paper Corporation of the United States, of New York, New York, under the designation Partwick #4400. The ink was blue and was applied to the release liner by letterpress printing.

The moldable composition was made from the following materials:

Component % (wt.) (Description)

(Commercial name; Supplier,- Location) hydroxyl terminated polybutadiene 12.49

(long-chain diene prepolymer) (Polybd R-45 HT; Elf Atochem, North America Functional Polymers Division, Philadelphia, Pennsylvania) polytetramethylenenoxide-di-p-aminobenzoate 4.64 (long-chain saturated prepolymer)

(Polamine 1000; Air Products Inc., Allentown, Pennsylvania) diethyltoluene diamine 0.25 (Ethacure 100; Ethyl Corporation, Baton Rouge, Louisiana)

1, 4 bu anediol 0.88

(ISP Technologies Inc., for GAF Chemicals, Wayne, New Jersey) sodium/potassium/aluminosilicate 0.21

(cross-linking initiator) (Lupersol PDO; Elf Atochem North America Inc., Fine Chemicals Group, Philadelphia, Pennsylvania) butyl stearate 1.48 (Kessco butyl stearate cosmetic,- Stepan Company, Northfield, Illinois) tetra (2,2 diallyloxymethyl-1-butoxy) titanium di(di-tridecyl) phosphite 0.19

(coupling agent)

(KR-55; Kenrich Petrochemicals, Inc., Bayonne,

New Jersey) polyalkyleneoxidemethylsiloxane copolymer 0.25 (surfactant)

(L-603; Union Carbide Corp., Danbury, Connecticut) polyisocyanate 6.39

(Isonate 143L; Dow Chemical Co., Midland, Michigan) silicon carbide mineral 72.22

(50 grade; average particle size 0.297 mm) (Minnesota Mining and Manufacturing Company, St. Paul, Minnesota)

The present invention has now been described with reference to several embodiments thereof. It will be apparent to those skilled in the art that many changes can be made in the embodiments described without departing from the scope of the invention. Thus, the scope of the present invention should not be limited to the structures described herein, but rather by the structures described by the language of the claims, and the equivalents of those structures.

Claims

Claims :

1. A method for providing indicia (20, 20') on a surface of a molded article (35, 35'), comprising the steps of:

a) providing a mold (10) having at least one molding surface (12) shaped to form a surface of the article (35, 35') ,-

b) providing indicia (20, 20') on the molding surface;

c) providing a sufficient quantity of moldable composition (30) to form the article (35, 35') ,-

d) placing the quantity of moldable composition (30) in contact with the molding surface (12) and the indicia (20, 20' ) ;

e) solidifying the moldable composition (30) to form the article (35, 35') ; and

f) transferring the indicia (20, 20') from the molding surface (12) to a surface of the article (35,

35') .

2. The method of claim 1, wherein step b) comprises providing indicia (20) directly on the molding surface (12) .

3. The method of claim 1, wherein step b) comprises providing indicia (20') on an indicia transfer medium (14) , and placing the transfer medium (14) adjacent the molding surface (12) .

4. The method of either claim 2 or claim 3, wherein the indicia (20, 20') is provided by silk screening.

5. The method of claim 3, wherein said indicia transfer medium comprises a release liner (14) .

6. The method of claim 2, wherein the molding surface (12) on which the indicia (20) is provided is coated with a release agent.

7. The method of claim 1, wherein steps e) and f) occur concurrently.

8. The method of claim l, wherein the moldable composition (30) is an abrasive precursor, and the indicia (20, 20') comprises alphanumeric characters that identify the abrasive characteristics of the article (35, 35') .

9. The method of claim 1, wherein step e) comprises heating the mold (10) to facilitate solidification.

10. The article (35, 35') made by the method of claim 1.

11. The method of claim 1, wherein the indicia (20, 20') is ink.

12. A method for providing indicia (20, 20') on a surface of a disc-shaped, molded abrasive wheel (35, 35'), comprising the steps of: a) providing a mold (10) having a circular molding surface (12) shaped to form a major surface of the abrasive wheel (35, 35') ;

b) providing indicia (20, 20') on the molding surface (12) ,-

c) providing a sufficient quantity of moldable abrasive precursor (30) to form the article (35, 35') ;

d) placing the quantity of moldable abrasive precursor (30) in contact with the indicia,-

e) solidifying the moldable composition (30) to form the article (35, 35') ,- and

f) transferring the indicia (20, 20') from the molding surface (12) to a surface of the article (35, 35') .

13. The method of claim 12, wherein step b) comprises providing indicia (20) directly on the molding surface (12) .

14. The method of claim 12, wherein step b) comprises providing indicia (20') on an indicia transfer medium (14) , and placing the transfer medium (14) adjacent the molding surface (12) .

15. The method of either claim 13 or claim 14, wherein the indicia (20, 20') is provided by silk screening.

16. The method of claim 14, wherein said indicia transfer medium comprises a release liner (14) .

17. The method of claim 13, wherein the molding surface (12) on which the indicia (20) is provided is coated with a release agent.

18. The method of claim 12, wherein steps e) and f) occur concurrently.

19. The method of claim 12, wherein step e) comprises heating the mold (10) to facilitate solidification.

20. The molded abrasive wheel (35, 35') made by the method of claim 12.

21. The method of claim 12, wherein the indicia (20, 20' ) is ink.

22. A molded article (35, 35') comprising a surface having indicia (20, 20') displayed thereon, said indicia bonded to and embedded in the surface of the article.

23. The article (35, 35') of claim 22, wherein the exposed surface of the indicia (20, 20') is coplanar with the surface of the article.

24. The article of claim 22, wherein the article (35, 35') is a molded abrasive wheel.

25. The article of claim 23, wherein the indicia (20, 20') comprises alphanumeric characters that identify the abrasive characteristics of the molded abrasive wheel (35, 35') .

26. The article of claim 24, wherein at least 50% of the components of the abrasive wheel (35, 35'), by weight, is abrasive mineral.

27. The article of claim 22, wherein the article (35, 35') is disc-shaped.

28. The article of claim 22, wherein the indicia (20, 20') is ink.