Kendall Co. v. Tetley Tea Co.

• Decision Date: 01 June 1951
• Docket Number: No. 4547.,4547.
• Citation: 189 F.2d 558
• Parties: KENDALL CO. v. TETLEY TEA CO., Inc.
• Court: U.S. Court of Appeals — First Circuit

189 F.2d 558 (1951)

KENDALL CO. v. TETLEY TEA CO., Inc.

No. 4547.

United States Court of Appeals First Circuit.

June 1, 1951.

Hector M. Holmes, Boston, Mass. (H. L. Kirkpatrick, Edgar H. Kent and Fish, Richardson & Neave, all of Boston, Mass., on brief), for appellant.

T. Clay Lindsey, Hartford, Conn. (George P. Dike, Boston, Mass., on brief), for appellee.

Before MAGRUDER, Chief Judge, and WOODBURY and HARTIGAN, Circuit Judges.

MAGRUDER, Chief Judge.

In this patent infringement suit, the court below gave judgment for the defendant upon a holding that the claims in suit are invalid. 89 F.Supp. 897. The patent in question, No. 2,277,050, is a product patent for an infuser, particularly a tea bag. It was applied for by Raymond E. Reed and John F. Ryan, designated as joint inventors, and was issued on March 24, 1942, to appellant herein, The Kendall Company, as assignee. The Kendall Company, a manufacturer of various woven and non-woven fabrics, does not itself manufacture tea bags, but it does manufacture a fabric known as "Webril", a form of which is designed for use in the making of tea bags. Using a competing material purchased from C. H. Dexter & Sons, Inc., the defendant-appellee Tetley Tea Company manufactures heat-sealed tea bags alleged to infringe the patent in suit. Dexter has conducted and controlled the defense of the case, having agreed to indemnify Tetley for any loss sustained on account of the alleged infringement.

Raymond E. Reed came to the Kendall Mills Division of The Kendall Company at Walpole, Massachusetts, in December, 1933, to take a principal part in a research project devoted to the development of a fabric which would not require the expensive processes of spinning and weaving. The broad idea was that thermoplastic fibers, particularly those of cellulose acetate, might be so treated as to form webs or fabrics either alone or in conjunction with non-thermoplastic fibers, such as cotton or wool, and that these cheaper materials might replace the more expensive woven fabrics. After many experiments it was found that an apparently useful product could best be formed by producing with textile machinery a web of cellulose acetate fibers and cotton fibers intermingled, and then subjecting the web to heat and pressure to develop the inherent adhesive properties of the cellulose acetate fibers so that they would adhere to each other and to the cotton fibers at intersecting points. Thus could be formed a material of some tensile strength, and wide variations in pliability and porosity depending upon the ratio of cellulose acetate fibers in the mixture and the degree of heat and pressure used. It was found preferable to add a plasticizer to the cellulose acetate fibers in order to lower the temperature at which the fibers would become adhesive, and such plasticizers were obtained on the commercial market. Reed and his co-workers also found that several webs so formed could be superimposed and subjected to heat and pressure to produce laminated products of varying thicknesses.

The experiments had reached such a state of development by July 5, 1935, that Reed, as sole inventor, on that day filed an application in the Patent Office (Serial No. 30,022) setting forth the above discoveries in considerable detail and describing the various types of fabric which might be produced by variations in the method. No mention was made in the application of the possible use of the fabric for the manufacture of tea bags or other infusers. On December 2, 1935, Reed filed an application for a patent for a collar and cuff interliner, which eventuated in patent No. 2,202,025 issued May 28, 1940, to Kendall as assignee; the disclosure in this application described the method of making the interlining material substantially as in the previous application (Serial No. 30,022), but the claims were limited to its use as a collar fabric. On November 6, 1939, Reed, as sole inventor, filed an application for a patent on a textile fabric and method of making the same, the application being described as "a continuation, in part, of my copending application Ser. No. 30,022, filed July 5, 1935." It is conceded that in essential parts "the continuing case discloses exactly the same invention described and claimed in the original application. In fact, most of the claims were taken from the original case, some of them being modified slightly in order better to define the invention, and many of them being copied verbatim." The earlier application, Serial No. 30,022, was afterwards abandoned, and the continuing application eventuated in patent No. 2,277,049, issued to Kendall as assignee of Reed, on March 24, 1942, the same date on which the patent now in suit was issued.

Meanwhile, by August of 1936, Reed had conceived the idea that a form of the above-described fabric, which goes by the trade name "Webril", and was so trademarked in 1938, might be useful for the manufacture of tea bags; and he experimented with the development of a satisfactory material for this purpose. He thought at that time, however, that it would be necessary to kier-boil and bleach the fabric after its manufacture in order to render it tasteless and non-toxic. This had been the process used in the making of the prior-art gauze tea bags, but such process when used on the Webril fabric chemically regenerated its thermoplastic fibers to pure cellulose and thus rendered the fibers no longer thermoplastic. Therefore, while the fabric was made originally as disclosed substantially in the 1935 application, it could not be made into a heat-sealed envelope, and could be used only in a stapled or sewed tea bag. The product in this form was apparently not marketed commercially.

In January, 1937, Reed went to work for appellant's subsidiary, Bauer & Black, in Chicago. In the following month Dr. John F. Ryan was employed at the Kendall plant in Walpole to work on various Webril products, including tea bags. When Reed returned to Walpole in August, 1938, he and Ryan collaborated on the further development of the tea bag. According to Reed's testimony, in late 1938 or early 1939 he and Ryan first conceived the idea of fabricating a material which would not have to be kier-boiled and bleached and which would be heat-sealing. During Reed's absence there had been developed an improved method of bleaching cotton fibers so that they would be pure and tasteless, and by experimentation Reed and Ryan found that at least two plasticizers were available which were tasteless and non-toxic. These plasticizers, prepared by Monsanto Chemical Company under the names Santicizers E-15 and M-17, had been known at least before 1937 and had been tried out by Reed on other products. To make the fabric heat-sealable, it was found preferable that a relatively heavy concentration of the thermoplastic fibers be placed on one surface and a light concentration on the other, so that the material would not stick to the heat-sealing machine. To accomplish this, Reed and Ryan designed a fabric consisting of three plies or webs hot-calendered together, the top web consisting of 60 per cent thermoplastic fibers, the other two containing only 5 to 10 per cent of such fibers. This material, known as Webril 1300, was placed in commercial production around August, 1939, the earliest sale appearing to be in the following month.

On August 31, 1940, Reed and Ryan, as joint inventors, applied for the patent in suit. Their disclosure opens by pointing out the wide use of infusers for the packaging of foodstuffs, such as tea and coffee, as well as their use by chemists, druggists, and others; and explains that for purposes of convenience the infuser will be referred to thereinafter as a "tea bag" and the material to be infused as "tea". The inventors then proceed to list as the three fundamental requirements of a satisfactory tea bag (1) that it be sufficiently water-permeable to allow rapid infusion, (2) that the structure of the bag be such as to prevent any substantial sifting through of the tea leaves, and (3) that it be very inexpensive to manufacture. They point out the disadvantages of the prior-art tea bags, such as those made of gauze or paper. They recite that they have discovered a way of making a satisfactory tea bag by using "an unwoven fabric from unspun fibers * * * preferably. * * * by mixing textile fibers of the common types with other fibers having latent adhesive properties, and then developing such properties and thereby uniting a sufficient number of the fibers to produce a coherent, porous fabric structure." As an example, it is stated that plasticized cellulose acetate and bleached cotton fibers in the proportions of 40 per cent of the former and 60 per cent of the latter may be mixed together by feeding into a picker lapper. "After the mixture has been converted into lap rolls on this machine, it is then carded and the webs from three carding machines are next superposed or combined to produce a single web which is subsequently treated to develop the latent adhesive properties of the cellulose acetate fibers. Such a treatment may consist in hot-calendering the combined web, the rolls being heated to a sufficient temperature to soften, somewhat at least, the exterior of the cellulose acetate fibers and thus make them adhere firmly to the cotton fibers." The disclosure points out that rayon and other non-thermoplastic fibers may be used in place of cotton, and that other thermoplastic fibers, such as vinyl, may be used as the binder. Further, the inventors indicate that while the above-described fabric is heat-sealable, a more satisfactory heat-sealing fabric can be made by concentrating a larger proportion of thermoplastic fibers on one surface; and they show how this can be done by placing on the top surface a web containing 60 per cent thermoplastic fibers and decreasing the proportion of such fibers in the other two webs to 5 or 10 per cent. In the specifications they do...