2. Description of the Related Art Seatboard is used for the rear portion or back part of the insole. This material is commonly also referred to as shankboard or tuckboard. It provides rigidity to the seat and waist of the footwear.

The production process for seatboard is similar to that for leatherboard. The raw material is chopped up and then pulped in rotary vats. The raw material consists of paper and cardboard together with scrap board from manufacturing. Kraft paper may make up a certain percentage of this material. Dye and binder may be added.

The fibers are separated from the bulk of the water and then opened up by refining. The slurry is finally delivered to a rotating drum. On the drum, the board is built up in layers before being cut, dried and calendered.

More specifically, seatboard products are manufactured by processing various refined or chopped up fiberboard products (e. g., scrap boards, used paper, cardboard boxes). These fibers and water are then pulped into rotary vats where dyes are added with a small amount of binders before additional mechanical refining action. The slurry is delivered to a fourdrinier wire belt leading to a rotating drum where the board is built up into layers before being cut and dried into sheets. The drying, curing and calendaring of the seatboard materials are usually done over several hours or even days, depending on the gauge and desired density.

Commercial grading is based upon the quality of the raw material used in the production. Commercial grade 1 is often characterized by its red color. It contains cellulose fibre produced form good quality Kraft. However, seatboard in many colors is available.

The dry and wet tensile strength of seatboard is important. In this regard, most seatboards are subject to perspiration and possibly external wetting during wear.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a manufacturing process for seatboard which is more efficient than the manufacturing processes presently used.

It is a further object of the invention to provide seatboard which is lighter in weight and density than conventional seatboard.

Yet a further object of the invention is to provide seatboard with improved directionality, i. e., more rigidity laterally in the side-to-side or machine direction (MD) and more flexibility longitudinally in the lengthwise or cross- machine direction (CMD).

Still a further object of the invention is to provide seatboard which is more resistant to delamination and has a higher internal bond and transverse tensile strength, a higher degree of abrasion resistance and less sensitivity to water than conventional seatboard.

In accordance with the foregoing objects, the invention relates to a seatboard which is highly water- resistant and is especially suited for use in the manufacture of soccer, golf, outdoor and other high performance footwear requiring an extremely rigid and water-resistant material.

The inventive seatboard material will contribute to making footwear lighter because the seatboard material is lighter in weight than conventional shankboards. The rigidity of the

seatboard is achieved through a unique combination of the density and the chemistry of the product. The inventive seatboard can be combined with conventional insole material to create a seatboard/insole forepart combination that has a high degree of water resistance and dimensional stability with rigidity in the seat and flexibility in the forepart.

The seatboard products are manufactured of elastomeric natural fibers, whereby the resulting product has high fiber-to-fiber bond strength and extreme rigidity side- to-side. These characteristics, along with dimensional stability, provides a product that will not harden, crack, buckle, or be affected by perspiration and is resistant to acids which can damage such materials as leather and reconstituted leatherboards.

The seatboard products are made of a composite matrix material having a substantially continuous web portion impregnated with a binder composition. The web portion of the composite material is made of a particulate, matrix-forming, natural fibrous material. The binder composition binds the particulate, matrix-forming material in the web and imparts water resistance to the composite material.

The composite material for the matrix may be made by methods based on paper making processes, specifically wet web impregnation. The impregnated matrix materials may be produced in gauges ranging from 80 to 350 millimeters. The impregnated matrix materials may be treated, for example, to resist mold and mildew.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is an exploded perspective view of a man's shoe having a seatboard in accordance with the present invention; and

FIGURE 2 is an exploded perspective view of a woman's shoe having a seatboard in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION Referring now to the drawings, there are shown men's and women's shoes having seatboards in accordance with the invention.

FIGURE 1 shows a man's welted brogue shoe 10 having a sole 12 with a seat piece 14. The shoe 10 has a heel 16 and top-piece 18. A sock 20 is inserted in the finished shoe.

The shoe 10 also has an insole 22 having a flexible forepart 22A and a seatboard 22B. The insole 22 is associated with a stiffener 24 and a toe puff 26. Between the insole 22 and the sole 12 are a shank 28, an insole rib for welt stitch 30, a rand welt 32, a bottom filler forepart 34, a waist filler 36 and a skeleton seat piece 38.

FIGURE 2 shows a woman's high heel pump shoe 40 having a sole 42 with a seat 44. The shoe 40 has a heel 46, heel breast 48 and heel flap 50. A sock 52 is inserted in the finished shoe. The shoe 40 also has an insole 54 with a flexible forepart 54A and a seatboard 54B. The insole 54 is associated with a stiffener 58 and a toe puff 60. Between the insole 54 and sole 42 are a shank 62 and bottom filler 64.

According to the invention, the seatboard is made of a composite material having a substantially continuous web portion impregnated with a binder composition. The composite material is a matted, felted, non-woven sheet containing a web portion optionally with web portion additives, and a binder composition optionally with binder additives. The web portion and web portion additives preferably comprise from about 50% to about 90% by weight of the dry weight of the composite material, and more preferably comprise from about 65% to about 75% by weight of the dry weight of the composite material.

The binder composition and binder additives preferably comprise from about 10% to about 50% by weight of the dry weight of the composite material, and more preferably comprise from about 25% to about 35% by weight of the dry weight of the composite material.

The web portion of the composite material includes at least one particulate, matrix-forming, natural component.

Examples of suitable particulate, matrix-forming, natural materials include: natural fibers including cellulosic fibers derived from a single source or a plurality of sources such as wood pulp, rags and cotton linters, and other cotton and vegetable fibers such as flax, hemp, abaca, jute, straw, ramie, sisal, istle, china grass, cotton grass, agave, pita, esparto, eucalyptus, evergreen and coniferous wood fibers, deciduous and broad-leaf hardwood fibers, comminuted and macerated waste fibers, viscose fibers, regenerated cellulose or cuprammonium type fibers, and rayon. An especially preferred matrix-forming material is virgin cellulosic fibers from one or more sources.

Preferably, the particulate matrix-forming component is a fibrous material having a denier of about 0.2 microns to about 40 microns and a fiber length of about 0.1 millimeter to about 20 millimeters.

In the following discussion the term"hard"is to be construed as meaning a"resinous type"firm reinforcing agent.

The binder composition is a hard latex material capable of binding the particulate matrix-forming component in the web and preferably includes at least one hard natural or synthetic rubber latex. Examples of suitable hard synthetic rubber latices include resins such as styrene-butadiene, carboxylated styrene-butadiene, polyacrylic ester, polymethacrylic ester, copolymers of acrylic ester and methacrylic ester, acrylonitrile-acrylic ester copolymer, polyvinyl acetate, polyisobutylene, a copolymer of vinyl

acetate and acrylic ester, polychloroprene, acrylonitrilebutadiene, carboxylated acrylonitrile butadiene, polyurethanes, a copolymer of ethylene and vinyl acetate, acrylonitrile butadiene styrene, polyvinylidene (di) chloride, carboxylated butadiene styrene vinylidene chloride terpolymers, polyisoprene (natural and synthetic) and other elastomeric co-, ter-, and multi-polymers. The binder composition may include a single hard natural or synthetic rubber latex or a mixture of two or more such hard rubber latices. An especially preferred binder composition comprises a synthetic rubber latex of carboxylated styrene-butadiene copolymers having a styrene content greater than 70% by weight.

The binder composition imparts water resistance to the composite material, while maintaining the other desirable properties of the web portion of the composite material.

The seatboard of the present invention differs from other elastomeric wet web fiberboard products primarily through the high level of hard resinous portion latex content. Latex usually represents about 20% of these products by weight, and typically the use of this hard latex in most stiff elastomeric insole materials is 70% of total latex content. With the seatboard of the present invention, the hard latex content is about 100% of the total latex content.

As noted above, both the web portion and the binder composition optionally contain additives. These additives function as processing additives and/or end product additives to achieve certain desired results during the manufacture of the composite material and/or to impart certain desired characteristics to the combination. Additives are classified as"web portion"additives and"binder"additives based on which component, the web forming component or the binder composition, the additive is initially mixed with. Thus, the

same types of additives can be both web portion additives and binder additives.

The additives useful in the composite material are conventional additives, which are used for their known properties in preparing the composite material of the invention. Examples of suitable web portion additives include antifungal agents, antimildew agents, antibacterial agents, dyes, pigments, dispersants, wet strength aids, web processing aids, defoamers and sizing agents. Examples of suitable binder additives include: surfactants, antioxidants, lubricants, crosslinking agents, catalysts, anti-ozonates, emulsifiers, wetting agents, colloidal stablilizing agents, vulcanizing agents, sizing agents, and defoamers.

The total amount of additives, both web portion and binder additives, in the composite material is preferably between about 0.5% and about 5.0% by weight based on the dry weight of the composite material.

A summary of typical properties of the seatboard product of the invention are as follows: PropertyResult/UnitPropertyResutt/Umt Density 0. 600 G/CBCM Swelling Length/Width 3% Max Weight 700 G/SQM Shrinkage Length/Width 2% Max Gauge Range 0. 90-2.75 MM Tensile Strength-A 6 N/SQMM Min ShoreHardness A 90-95 Tensile Strength-B 12 N/SQMM Min Water Absorption 35% Max Breaking Elongation-A 5% Min Water Emission 90% Min Breaking Elongation-B 9% Min Composite materials for use in this invention can be made by modified paper-making processes wherein an aqueous slurry of the matrix-forming component and optionally the web portion additives is formed and then the slurry or a web

formed from the slurry is impregnated with the binder composition and optionally the binder additives. The wet web impregnation process, which is a modified paper-making process, in particular can be used to make the composite material for the combination of this invention. This process will be described briefly below. A detailed example of this type of process can be found in U. S. Patent No. 4,245,689.

In the following discussion, the term"fibrous"is to be construed as including particulate matrix-forming materials which are not technically fibers. However, since the basic processes discussed herein are modified paper making processes, which do involve primarily cellulosic fibers as the web or matrix-forming component, the conventional term "fibrous"will be used.

In the wet web impregnation method, the fibrous matrix-forming component (s) and web portion additive are dispersed in water to prepare a slurry stock and the slurry stock passes through a refiner or beater which cuts the fibers and ruptures the surfaces of the fibers to improve their bondability. The refined slurry stock is fed to a sheet former of conventional construction. On the sheet former, a fibrous web is formed by removal of water from the approximately 99% by weight water content of the refined slurry stock feed to a fibrous web having about 72% by weight water. Following formation of the continuous fibrous web on the sheet former, it passes to a press section which removes water from the web to reduce the water content to about 50% to 60% by weight. The pressed web then passes to a saturator which introduces the binder composition and binder additives into the fibrous web. Excess binder composition and binder additives are removed from the fibrous web and then the binder impregnated fibrous web passes to dryers which dry the impregnated web to a moisture content less than about 3% by

weight. Subsequent conventional steps such as printing and coating and the like can then be performed as desired.

To summarize, the fundamental differences between the present seatboard and conventional seatboards is (1) the rigidity of the conventional shankboards is primarily through density, and the rigidity of the present seatboard is primarily through the chemistry (i. e., hard latex binder); and (2) the present seatboard is manufactured through an elastomeric wet web process and conventional tuckboards are manufactured by a beater addition process rather than a continuous wet web process.

The above method is an example of a method for making the composite material for the seatboard of the invention, but should not be construed as the only suitable method. The composite material made by the above method is in the form of large, continuous sheets which can be cut to seatboard shape and stacked, or can be rolled around a supporting core for later use.

The invention has been described with reference to preferred embodiments and specific examples thereof which are considered illustrative only of the principles of the invention. Since numerous changes and modifications will readily occur to those skilled in the art, it is not desired to limit the invention to the exact embodiments shown and described, and suitable modifications may be made without departing from the scope of the invention as described above and as defined in the appended claims. For example, and in addition to seatboards, the products of the present invention may have application in automotive, furniture and similar industries.