USM Corp. v. Detroit Plastic Molding Co.

536 F. Supp. 890
CourtDistrict Court, E.D. Michigan
DecidedFebruary 23, 1982
DocketCiv. A. No. 76-72536
StatusPublished

This text of 536 F. Supp. 890 (USM Corp. v. Detroit Plastic Molding Co.) is published on Counsel Stack Legal Research, covering District Court, E.D. Michigan primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
USM Corp. v. Detroit Plastic Molding Co., 536 F. Supp. 890 (E.D. Mich. 1982).

Opinion

MEMORANDUM OPINION

JULIAN ABELE COOK, Jr., District Judge.

I.

INTRODUCTION

A. The Patents-In-Suit

On December 4, 1973, Plaintiff, USM Corporation (USM), as assignee of inven[905]*905tors, R. E. Annis, Jr. (Annis) and W. T. Kyritsis (Kyritsis) was granted United States Patent 3,776,989 (989 Patent). This Patent is entitled, “Method for Injection Molding Articles of Foam Material Involving Autogenous Flow.” The abstract thereof provides a concise summary of its disclosure:

“A process of molding articles of foam material comprising forming a mixture of organic polymeric resin material and a blowing agent in a chamber at a temperature below the foaming temperature of the resin-blowing agent system and forcing the mixture through a restriction for resisting the flow of the material to impart heat to the material, the heat imparted being of a magnitude sufficient to raise the temperature of the mixture to the foaming temperature, and discharging the mixture, at its foaming temperature, into a mold cavity.”

On April 2, 1974, USM, as assignee of inventors, Kyritsis and R. C. Simmonds, Jr. (Simmonds), was granted United States Patent 3,801,686 (686 Patent). This Patent is entitled, “Method of Injection Molding Articles of Foam Material.” The abstract thereof states:

“Method of injection molding articles in which a mixture of injection molding material and a blowing agent at a temperature below the foaming temperature is brought to foaming temperature directly before the mixture enters the mold and is introduced into the mold to fill the mold cavity during the induction period of the blowing agent. The blowing agent is deactivated in portions of the mixture which contact the walls of the mold and the volume of the mold cavity is increased to allow that portion of the mixture which is not in contact with the mold walls to expand.”

B. The Pleadings

Qn December 9, 1976, USM filed a Corn-plaint, which alleged infringement of these two Patents by Defendant, Detroit Plastic Molding Company (DPM). In its answer, DPM denied infringement. It also filed a Counterclaim, which sought a declaratory judgment that the Patents-in-suit are invalid.

C. The Trial

This matter was tried by the Court without a jury over thirty-four trial days. USM called twelve witnesses to testify and DPM called four witnesses, including two persons who had already testified for USM. The Court found the following witnesses to be most helpful in the resolution of the issues:

—Donald Chabot (Chabot) and Allen Sampson [executive employees of USM] testified concerning the history of plastic molding, as well as the research, development and marketing of the USM foam process;
—Michael Ladney (Ladney) [President and primary shareholder of DPM] testified concerning the DPM process;
—William Gore and Harry Fain [employees of General Motors Corporation], David Gonda [an employee of DPM] and Joseph Gualdoni [an agent of DPM] testified about the contract under which DPM supplies foam plastic glove box doors to General Motors;
—Dr. Byron Hunter (Hunter) [chemist and the inventor of the blowing agent used by DPM] testified concerning its behavior;
—Robert Simmonds [engineer for USM and co-inventor of the 686 Patent] was USM’s technical expert concerning the Patents-in-suit, as well as the DPM process;
—James Hendry [engineer with Excello Corporation] was DPM’s technical expert.1

[906]*906The Court also received numerous documents and physical exhibits into evidence.2

In its deliberations after the trial, the Court had the benefit of the parties’ Post-Trial Briefs, Proposed Findings of Fact and Conclusions of Law, and Reply Briefs.

This Opinion constitutes the Court’s Findings of Fact and Conclusions of Law, as required by Rule 52, Federal Rules of Civil Procedure.

D. The Background of the Controversy

(1) As is apparent from the abstracts of the above-quoted Patents-in-suit, these Patents involve a foam plastic injection molding process. That process is grounded in the conventional (non-foam) plastic injection molding process. Both processes utilize an injection machine consisting of a hopper, a barrel, a screw, a shut-off valve, a nozzle and a mold. In both processes, plastic pellets are loaded into the hopper directly into one end of the barrel,3 which contains a screw. This screw serves three purposes. Its mechanical action not only heats the pellets to melt them, but also moves the plastic from the hopper end of the barrel to the nozzle end. Finally, the screw operates to ram the melted plastic through the opened shut-off valve, through the nozzle and into the mold. Therein the plastic cools, solidifies, and takes the shape of the mold. After the plastic solidifies, the mold is opened, and the molded part is removed. Thereafter, the mold is closed, and the machine cycles once again by injecting another shot of melted plastic into the mold.

It has been well known for a long time in the conventional injection molding art that it is crucial to control the temperature of the plastic as it enters the mold. If the plastic is too hot, the finished parts will exhibit splay and blisters. If the plastic is too cold, the finished parts will exhibit sink marks and lack of fill. Thus, the concept of a “temperature window" in the conventional injection molding process is well known.

The methods of controlling the temperature of the plastic upon injection into the mold are also well known. There are several process parameters that can be adjusted to control that temperature, including the temperature of the barrel (which may be controlled by heating or cooling), the residence time of the plastic in the barrel, and the injection rate.4 Those who practice this art have been fully knowledgeable in the experimental procedures that are necessary with respect to these process parameters, in order to set up and operate the conventional injection process to achieve acceptable part quality.

(2) The difficulty with the conventional process arises out of the fact that as plastic cools, it contracts and sinks develop, most notably in the thicker sections of the part.

Thus, beginning about 1960, there was substantial research into the use of foam in the injection molding process. The concept is simple enough. By adding to the plastic in the barrel a chemical called a blowing agent, which decomposes into a gas when sufficiently heated, the plastic would be “foamed” after injection into the mold and the sink problem would be solved. Especially attractive to industry is the “sandwich constructed” part, the inner portion of which has a cellular structure, and the outer skin portion of which is solid. This solid outer portion allows the surface detail of the mold to be precisely reproduced. Such a part is also lighter and uses less plastic than a similar non-foamed plastic part.

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Bluebook (online)
536 F. Supp. 890, Counsel Stack Legal Research, https://law.counselstack.com/opinion/usm-corp-v-detroit-plastic-molding-co-mied-1982.