Opinion ID: 1036600
Heading Depth: 2
Heading Rank: 1

Heading: Technical Overview

Text: The patents-in-suit relate to multi-layer elastomeric laminates found in the body-hugging areas of products such as the waistband or side tabs of disposable diapers or adult incontinence products. The claims disclose stretchable films or laminates that, once affixed to the diaper, allow the product to expand to fit around the person wearing them with the laminate stabilizing to recover its shape once stretching is complete. The elastomeric nature of the laminate is discussed in all four patents.1 United States Patent Nos. 5,501,679 (“the ’679 Patent”) and 5,691,034 (“the ’034 Patent”)—the Krueger Patents—share a largely identical written description and are directed to laminates with “continuous” microtexturing over the laminate’s skin layer. See ’034 Patent col. 28 ll. 40-45; ’679 Patent col. 3 ll. 15-45. United States Patent Nos. 5,468,428 (“the ’428 Patent”) and 5,344,691 (“the ’691 Patent”)—the Hanschen Patents—are 1 All of the patents in suit name more than one in- ventor. When discussing the prosecution history, we collectively refer to the multiple inventors as “the applicant.” Consistent with the manner in which the parties presented arguments, we divide the asserted patents into two groups and discuss them accordingly. We refer to U.S. Patent Nos. 5,501,679 and 5,691,034 by reference to lead inventor, Dennis L. Krueger (“the Krueger Patents”). We refer to U.S. Patent Nos. 5,468,428 and 5,344,691 by reference to lead inventor Thomas P. Hanschen (“the Hanschen Patents”). The two Krueger Patents and the two Hanschen Patents share nearly identical written descriptions. 3M INNOVATIVE PROPERTIES v. TREDEGAR CORPORATION 5 in Figure 2, stretching has resulted in microtexturing of the laminate, seen as folds between the skin and core layers: ’034 Patent col. 3 ll. 42-46, col. 10 ll. 62-65. The microtexturing that occurs upon stretching provides elasticity, durability, and gives the expanded garment a soft feel. Id. at col. 11 ll. 35-42, col. 13 ll. 1-8, col. 13 ll. 22-30. Both the Krueger and Hanschen Patents address problems resulting from the inflexibility of the materials used in the prior art to manufacture a diaper waistband or the protective back sheet or top sheet of a diaper. See, e.g., ’034 Patent col. 3 ll. 1-8; see also ’691 Patent col. 2 ll. 12-14 (“Problems with these elastomeric films include the difficulties inherent in applying a stretched elastic member to a flexible substrate such as a disposable diaper.”). For example, the Krueger Patent disclosure explains that the lack of flexibility in earlier laminates results in an uncomfortable stiffness that can cause the material to “bite” or “grab” the wearer of the diaper. ’679 Patent col. 3 ll. 6-11. Additional problems were discussed with the PTO examiner during prosecution. In the application that later issued as the ’679 Patent, the examiner considered U.S. 6 3M INNOVATIVE PROPERTIES v. TREDEGAR CORPORATION Patent No. 4,880,682 (“Hazelton”) and U.S. Patent No. 5,057,097 (“Gesp”) and noted that “neither Gesp nor Hazelton et al. disclose films capable of recovering slowly over time at ambient conditions or capable of substantial heat activated recovery” as claimed in the ’679 Patent application. J.A. 1257. In these prior art laminates, the outer skin layers deformed when stretched; the deformation impeding recovery because there was only intermittent contact between the skin and the core. E.g. J.A. 1526; see also J.A. 1257. 3M maintains that separated skin and core layers exposed the core to oxidation, thereby decreasing the effectiveness of earlier films. The Krueger Patents overcome some of the problems associated with robust stretching by allowing the laminate to recover following deformation. The “continuous contact” between the layers allows for recovery from deformation because the microtexturing—i.e. folds in the skin layer—allows the laminate to withstand the compromising effects of the skin and core being pulled apart. Claim 1 in the ’034 Patent recites the arrangement of the layers: 1. An elastomeric laminate consisting essentially of at least one elastomeric layer and at least one continuous microtextured skin layer over substantially the entire laminate wherein: (a) the microtexture on said skin layer is formed by stretching an untextured laminate past the de- formation limit of at least one untextured skin layer and allowing the stretched laminate to elastically recover over the entire region stretched and (b) said at least one elastomeric layer and said at least one continuous microtextured skin layer are in substantially continuous contact. ’034 Patent col. 28 ll. 40-45. Claim 1 of the ’679 Patent provides additional detail as to the nature of the micro- 3M INNOVATIVE PROPERTIES v. TREDEGAR CORPORATION 7 texturing found on the skin layer that is in “continuous contact” with the elastic core layer:
body engaging area comprising an elastomeric laminate comprising at least one discrete elastomeric layer and at least two discrete continuous skin layers at least one of which is a microtextured perma- nently deformed polymeric layer wherein the materials forming the elastomeric layer and the materials forming the polymeric layer are selected such that said at least one elastimeric layer and said at least one microtextured skin layer are in continuous contact. ’679 Patent col. 28 l. 61 to col. 29 l. 2. The Hanschen Patents depart from the Krueger Pa- tents in that they teach a laminate with “preferential activation zones.” As explained in the ’691 Patent disclosure, the laminates claimed in the Hanschen Patents “are capable of becoming microtextured at specified areas along the laminate length.” ’691 Patent col. 3 ll. 11-13. The microtextured areas correspond to sections of the laminate that have been “activated from an inelastic to an elastomeric form.” Id. col. 3 ll. 13-15. The Hanschen Patents thus limit elasticity to specific areas claimed as “preferential activation zones.” Claim 1 of the ’691 Patent is representative of the claims relating to “preferential activation zone.” Claim 1 states: 1. A multi-layer film laminate comprising at least one nonelastomeric skin film layer and at least one core film layer, the at least one skin film layer and the at least one core film layer together forming at least one preferential activation zone where the film laminate will preferentially elongate when stretched, wherein said at least one core film layer is substantially elastomeric, each of said core and skin layers being substantially coextensive and having relatively constant average thickness over 8 3M INNOVATIVE PROPERTIES v. TREDEGAR CORPORATION both the at least one preferential activation zone and an at least one adjacent non-preferential activation zone such that, for a given skin or core layer, the skin or core layer thickness in one zone will be substantially the same as the same skin or core layer thickness in all zones, said at least one skin film layer and/or at least one core film layer are provided such that when the multi-layer laminate is stretched said at least one preferential activation zone will preferentially elongate and can recover in said preferential activation zone to become an elastic zone, of said multi-layer film laminate, and adjacent multi-layer non-preferential activation zones will not preferentially elongate to provide substantially inelastic zones. ’691 Patent col. 36 ll. 41-63. The claimed zone can be activated by conditions producing designated stretch ratios. The Hanschen Patents depart from the Krueger Patents in that those patents require a lower stretch ratio to effectuate stretching or activate the microtextured laminate. See ’691 Patent col. 3 ll. 34-49. In particular, the Hanschen Patent disclosure teaches that when stress is applied to a localized region, there will be preferential elasticization of the specified zone. See id. col. 3 ll. 38-58, col. 10 l. 11 (identifying methods of “post formation stress localization” or “controlled localized stretching”).