US2826831A

US2826831A - Integral molded pulp sole and heel

Info

Publication number: US2826831A
Application number: US325935A
Authority: US
Inventors: Pollak Robert
Original assignee: Individual
Current assignee: Individual
Priority date: 1952-01-11
Filing date: 1952-12-15
Publication date: 1958-03-18
Anticipated expiration: 1975-03-18

Description

March 18, 1958 v R. PoLLAK INTEGRAL MOLDED PULP soLE AND HEEL Filed Dec. 15, 1952 JNVENToE Kobe# P0 [Lak ATT RNEYS INTEGRAL MOLDED PULP SOLE AND HEEL Robert Pollak, London, England Application December 15, 1952, Serial No. 325,935

Claims priority, application Great Britain January 11, 1952 2 Claims. (Cl. 36-25) This invention relates to the construction of footwear. In the conventional methods of construction of leather footwear the shoes, boots, sandals or the like lare commonly made up of an outer sole, an insole and an upper. cut out from sheet leather. With such a method of construction, the appearance and wearing qualities of the footwear are substantially dependent upon the quality of the leather used which result in high production costs and considerable waste because only the better parts of the leather, hides or skin can then be made use of.

It is the object of the present invention to provide an improved construction of footwear from leather material wherein a good appearance and hard-wearing qualities may be imparted to the leather irrespective ofthe quality or size of the leather used as abasic material, such construction more particularly permitting the utilisation of scrap leather, cuttings and other waste which could not normally be used for a shoe construction.

Fig. 1 is a side elevational view of a shoe comprising a molded pulp sole and heel assembly embodying the present invention, the upper part of the shoe being shown in dotted outline; and

Fig. 2 is a sectional view taken on line 2 2 of Fig. l.

Accordingto the present invention, there is provided a shoe' construction made from leather material formed by reducing leather to a fibrousV state, for instance in a suitable mill, suspending the bres in ya carrying liquid such as water, as is done for instance in paper making, placing the suspension in an accretion forming die, preferably after treatment vin a beater, and accreting the suspended fibres, in the usual manner to form individual parts of or a complete article of footwear.

Accretion moulding is commonly carried out with the aid of a mold having the shape .of a hollow box, the outline of onel side of which conforms tothe shape of the article to be molded and is usually perforated, and a tine wire gauze is placed over that part. The mold, which is connected to vacuum means, is then immersed in the suspension of fibres. Vacuum is applied to the mold by opening a suitable valve and the water is drained through the wire gauze so that the fibres which were suspended in the water form a layer on the mold. This layer conforms of course to the shape of the mold. The turbulence created by the suction causes the fibres to interlock and to felt and it will be apparent that if suitable binders are added to the suspension, an article formed in this manner will have considerable strength. The thickness of the layer of these felted fibres depends upon the quantity of suspension which is introduced into the mold.

Where the whole shoe is not produced as a single molding, the various parts of a shoe may be assembled and united by any suitable conventional method, such as sewing, nailing, cementing and so on, or any combination thereof.

For the production of the various parts of the footwear, various suitable tanned and graded fibres may be used. The thickness of the molding will also be appropriate to the part of the footwear being made. Again United. .StatCS Patent the suspension from which the bottom parts, e. g. the soles, are to be produced may have incorporated therein suitable hardening and water-repellent agents, while the suspension from which the uppers are to be made may contain plasticizers. n

Suitable types of hardening and water-repellent agents include the vinyl polymers of which polyvinyl chloride, polyvinyl acetate, and polyvinyl butyrate are illustrative. Other rsynthetic resin impregnants may be used, including polyethylene and polytetrauoroethylene, and in general any resin polymers employing a (hC- Q*:Cm type linkage. It is also possible to use polyamide and isocyanate containing polymers, such as nylon and Perlon. Further, natural and synthetic rubbers, as for example the buna type, as well as'neoprene and chloroprene, may be used. These resins may of course be plasticized with the customary plasticizers. Also, synthetic resins of the thermosetting type such as phenolformaldehyde, ureaformaldehyde, etc. may be used.

Further, when desirable, a whole article of footwear or a part thereof maybe molded as a unit and then an additional part, e. g. a molded pulp hard-wearing outer sole, added thereto.

If desired, it is also possible to fabricate laminated artiy cles, as for example, a combination sole and insole in 4 which the sole portion may be made up of two or more molded pulp layers with the second distinct layer being formed of interwoven and felted fibres of a less durable character than the leather fibres, as for example, paper pulp fibres or cloth fibres. This molding operation may be accomplished by first immersing the lforming die in a suspension of leather fibres to accumulate the outer sole preform, and subsequently immersing the forming die in a second suspension containing the other type fibre material to accumulate a second layer of such material in intimate and interfelted relationship with the initial layer. The composite laminated sole member may thereafter be compacted and compressed between mating dies to the final desired shape, or alternatively may be subjected to further operations as herein set forth.

The part `or whole of a shoe is formed to shape by thefirst stage of construction, and its further treatment may consist of surface nishing such as coloring or graining. .For example the upper may have one or more colors added thereto by spraying or other suitable method. Again, graining and the like may be applied by a pressing treatment.

A suitable surface finishing treatment consists in com- A pressing the molded article' or` part between the surfaces of a defining die which may have, for instance, one surface of yielding material and adapted to press the article or part against a rigid plain or patterned surface to form a corresponding surface thereon. If grain and colors are required a plain pressing operation should be carried out first, the coloring preferably with cellulosic paints being the second and subsequent stage, then a further pressing treatment applied in the defining die after the paint has dried to give the required grain as a third stage.

Suitable examples of the -cellulosic type paints include cellulose acetate and cellulose butyrate in organic solvent carriers. Alternatively, pigments and/or organic dyes may be added to the suspension from which the footwear articles are molded. In some cases it may be desirable to add plastcizers, as for example dibutyl phthalate, tricresyl phosphate, etc., to the synthetic resin impregnants or to the coloringmaterial.

In the conventional leather outer sole, a filling of wax etc. is added to lessen water absorption by the leather which can quickly ruin it, and it is a disadvantage of such conventional soles that they are more commonlyV 3 orV synthetic resins may be introduced during the prepar ing of the fibrous suspension and thereby the finished article will be made practically moisture-proof and its useful life increased.

Since a molded structure'of this kind may be' hollow,

it might be necessary to give the heel portion structural strength by filling the cavity withV a wooden, composition or other suitable heel insert.

This may be made in parts and fixed into theA heel cavity with a wedge-like part.

For the finishing i. e.` pressing, operation of the hollow heel portion, the article may be inserted in a suitable die and then a hollow rubber or like internal die inserted into the hollow heel and hydraulic Aor air pressure applied to the internal die will force the heel` firmly to shape.

Again, for the nishing'or pressing of hollow portions or a shoe as a whole an internal hollow tlexible die, e. g. made of rubber and having substantially the shape of a last, is inserted in to the hollow portion and compressed fluid pressure is applied to the hollow flexible die to inflate it and force the hollow portion of the shoe exactly to shape in a shaping die having an internal shape or outline of the footwear to be pressed.

A preferred constructionA comprises an article made by molding separateV parts of the article of footwear from an appropriate suspension in separate operations, whereafter they are dried 'and' finishing or surface treatment appropriate to the part of the shoe is applied thereto, the' parts then being assembled preferably by cementing in a shaping die with the aid of an internal flexible hollow die, made for example of rubber, inserted within the article of footwear and to which fluid pressure is applied;

If required, the dies may be heated.

In certain instances, as for example when thermosetting resin additives have been incorporated in the fibre slurry, it will be desirable to employ heated dies in which the preformed felt fibre parts may be finished to the desired shape: simultaneously with` the curing of the resin additive.

Such construction of footwear permits any size or quality of leather to be used without distinction, and the resultant footwear may be made more resistant to moisture and abrasion than conventional footwear. i

Figs. l and 2 show a shoe embodying the present inven'toni which includes an integral molded pulp construction assembly 100, comprising a sole portion 102 and a hollow heel portionV 104.` This assembly` 100 includingY members 102 and `104 is attached t'o a shoe indicated in dotted outlineY at 106.

Within the hollow heel portion 104 is provided a structural filler 108. A weanresisting layer 110 macle` of i molded pulp composition 4 f is provided on the bottom of the sole portion 102.

Obviously many` modifications and variations of the present invention are possible in the light of the above teachings. It is therefore, to be understood that within the scope of the appended claimsthe invention may be practiced otherwise than as specifically described.

I claimt' 1. A combination shoe sole and heel in which the heel stands higher than the sole, the combination being an integrally formed pulp member having a hollow heel formation defined by a peripheral side wall and a bottom wall, the hollow in the heel formation filled with a structural filling, and said pulp member having an interfelted covering layer of wear-resisting pulp composition on the bottom of the sole portion.

2. The combination of claim l wherein said sole is provided with ani extension overlying said hollow heel formation.

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