Stacked laminate mold and method of making

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TECHNICAL FIELD

The present invention relates generally to methods of forming a mold and to such a mold, and more particularly to methods of forming stacked laminate molds and to such stacked laminate molds.

BACKGROUND OF THE INVENTION

Stacked laminate molds and their use are known. In one known mold, a plurality of plates can be formed having V-shaped grooves cut through a top edge of the plate with the V-shaped groove extending from a first surface to a second surface of the plate with the bottom of the groove being parallel to the top surface of the plate. Adjacent plates may be staggered such that the grooves in one plate are bounded by the major surfaces of the plates in front and in back of such plate. Such plates have been known to be used, for example, for forming molded piled products. One example of a stacked laminate mold is taught in U.S. Pat. No. 3,312,583, "Apertured and Staggered Molded Piled Product" (Rochlis).

It has also been known to use stacked laminate molds for making the hook component of hook-and-loop fasteners. In such molds, it is known to form complex hook-shaped engaging members with a stacked laminate mold by etching or engraving a cavity into a major surface of a mold plate, the cavity having the desired hook configuration such as a J-hook or nail headed hook member. The cavity is open to the top surface of the stacked laminate mold. A plurality of such hooks can be formed across the length of one mold plate, with a plurality of similarly configured mold plates placed adjacent to one another. All of the plates may include cavities, or spacer plates without cavities may be placed between plates with cavities. Such stacked laminate molds can be used for batch production, that is for making discrete lengths and widths of molded products having a plurality of hooks. See for example U.S. Pat. Nos. 3,147,528, "Separable Fastener Element" (Erb); and 5,368,549, "Method for Injection-Molding an Orthopedic Device and Product of the Method" (McVicker). It is also known to use circular-shaped stacked laminate molds for continuous production of molded strips having a plurality of hooks. See for example U.S. Pat. Nos. 3,762,000, "Production of a Continuous Molded Plastic Strip" (Menzin et al.); 3,196,490, "Apparatus for Manufacture of a Continuous Strip of Molded Plastic Product" (Erb); and 4,872,243, "Multi-Hook Fastener Member" (Fischer); and Rosato and Rosato, Injection Molding Handbook, VanNostrand Reinhold Company, pp. 753-56.

It has also been known to use stacked laminate molds in the production of retroreflective or triple-reflective material. The stacked laminates are generally configured so as to form three full surfaces of a cube when the adjacent plates are stacked together for molding the retroreflective product. See for example U.S. Pat. Nos. 1,591,572, "Process and Apparatus for Making Central Triple Reflectors" (Stimson); 3,649,153, "Faceted Core" (Brudy); 4,066,236, "Cube Comer Type Retroreflector Bodies and Molds Made Therewith" (Lindner); and 4,095,773, "Subassemblies for Cube Comer Type Retroreflector Molds" (Lindner); and German Provisional Publication (OS) 42 36 799 A1 (Gubela).

Methods for forming an electrically conductive coating on non-conductive mold surfaces are known, as are methods for electrodepositing a metal coating onto a mold surface. See for example U.S. Pat. Nos. 4,871,623, "Sheet-Member Containing a Plurality of Elongated Enclosed Electrodeposited Channels and Method" (Hoopman et al.); and 5,070,606, "Method for Producing a Sheet Member Containing at Least One Enclosed Channel" (Hoopman et al.)

SUMMARY OF THE INVENTION

The present invention presents a stacked laminate mold, and methods of making stacked laminate molds. Such a stacked laminate mold may be used to mold a desired article or may be used to mold a subsequent mold. When the stacked laminate mold is used to mold a subsequent mold, an inverse of the stacked laminate mold can be made, for example, by electrodepositing a metal coating on the stacked laminate mold and removing the metal inverse from the stacked laminate mold. This metal inverse can be used to mold a desired article, or may itself be an intermediate mold. When the metal inverse is an intermediate mold, it is possible to form an inverse of the metal inverse to obtain a mold that is a replicate of the mold surface of the stacked laminate mold. Such a replicate can comprise, for example, an electrodeposited mold, a plastic mold, a silicone mold, or any other desired material.

In one preferred embodiment of the present invention, a stacked laminate mold is formed having cavities that are the inverse of the desired final article. Such a mold may be referred to as a "negative" mold, as its configuration is the negative of the final desired article. The stacked laminate negative is then used to produce a metal "positive" mold by electrodepositing a metal coating, such as nickel, onto the stacked laminate negative. This metal positive has a mold surface that is the same as, in other words a "positive" of, the surface of the final desired article. This metal positive is then used to form a "negative" mold that is a replicate of the original stacked laminate mold, having a configuration that is a negative of the final desired article. This negative mold can comprise any desired material, such as a suitable plastic or silicone composition. This final negative mold can then be used to form the final desired article. In one preferred embodiment, the molded article comprises a generally planar base sheet having a plurality of protrusions extending therefrom, the protrusions being formed by the cavities in the mold.

While the above-described system is a preferred embodiment, it is understood that the stacked laminate mold may be used to directly mold a desired article, or that any number of intermediate molds may be made on the way to molding the ultimate desired molded article. In that regard, it is understood that the stacked laminate mold may be either a negative or positive of the final desired article.

The stacked laminate mold of the present invention is made by a method which provides a convenient and accurate way of forming mold cavities having accurately controlled surfaces, and edges between surfaces that closely approach a true linear edge. This accuracy can be replicated in the subsequent intermediate molds and in the final molded article.

One preferred embodiment of the present invention presents a method of forming a stacked laminate mold. The method comprises the steps of: a) orienting a plurality of plates to have their respective major planes at a first angle relative to a fixed reference plane and parallel to one another, each of the plates including op