GB2067199A - Foamed pads - Google Patents

Abstract

A pad, suitable for use in an article of footwear, comprises a foam material 1 whose pores are essentially spherical and the cross-sections of which decrease evenly towards the edges of the pad. The pad may include a flexible covering layer 2 and a layer 3 of a reactive adhesive which may be protected by a film 4. <IMAGE>

Description

SPECIFICATION Pad This invention relates to a pad for use in shoes, which comprises a foam material core with soft elastic properties and a thickness which decreases evenly towards its edges. Such a pad, covered with a surface material and coated on its underside with an adhesive, is commercially available and provides a reinforcement for use in shoes, especially for particular orthopaedic requirements.

The core of pads of the type described, of a foam material, have an equivalent cell structure and, therefore, equal elastic properties in all regions. Such pads are therefore often unsuitable for the provision of equal support for all areas of a human foot, with its pred,ominantly rounded upper surface areas. For use in particular circumstances, such pads must be prepared individually.

According to the present invention, a pad comprises a foam material core which contains closed, essentially spherical pores whose diameters decrease evenly towards its edges.

In a pad according to the invention, the diameters of the spherical pores are largest in the area in which the foam material has its greatest thickness. The elasticity and, in particular, the elastic deformability of the pad is therefore greatest in this area, and these properties decrease evenly towards the edges of the pad. The outermost edges of the pad may be wholly free of pores and, in this case, the mechanical resistance at the edges is comparable to that of leather.

A pad of the invention may comprise a polymeric material. The preferred material is a closed-cell, foamed, cross-linked polyolefin, and preferably a polyethylene, having a bulk density of 70 to 90 kg/m3. The maximum cell cross-section of such a material is about 0.8 mm. It may be prepared as a material width in a continuous process, provided on its upper face with a covering layer adhered thereto by flame-lamination, and subsequently formed into the desired shape. An adhesive may be applied to the opposite face.

After heat treatment, a pad of the invention or a material width from which a pad is cut, may be embossed or otherwise formed. The pressure of the gas in the pores in the foamed material may thereby be increased as the pore size decreases towards the edges of the product. The strength of the pad therefore increases towards the edges thereof, and this is particularly desirable.

The polyolefin foam is preferably chemically cross-linked to a degree of between 30 and 60%.

If a pad of the invention is covered with a suitable covering material, this material is preferably a synthetic leather of fleece material polished on its outer face. Polishing removes fibre ends from the fleece material and causes fibres to stand out perpendicularly from its surface. The proud fibres serve to give a foot in contact with the material a sure hold.

The invention will now be described by way of example with reference to the accompanying drawings, in which Figure 1 shows a pad embodying the invention in longitudinal crosssection, and Figure 2 shows the same pad in plan view. A foam material core 1 has pores whose cross-sections decrease evenly towards the edge zones thereof. The core has a flexible covering layer 2 on its upper surface and, on its underface 3, a layer of a reactive adhesive which is protected against drying by a covering film 4 of, for example, polyvinyl chloride.

Figure 2 shows that the covering layer 2 covers the upper face of the foam material core completely. This allows for the provision of an even transition between the non-reinforced areas of a shoe and the soft elastic centre of the foam material core.

A pad according to the invention may be used in heel or tongue reinforcements in articles of footwear, e.g. shoes.

1. A pad comprising a foam material, the pores of which are essentially spherical and whose cross-sections decrease evenly towards the edges of the pad.

2. A pad according to claim 1 in which the foam material is wholly free of pores at the edges thereof.

3. A pad according to claim 1 or claim 2 in which the foam material comprises a closed-cell foamed cross-linked polyethylene having a bulk density of 70 to 90 kg/m3.

4. A pad according to any preceding claim having a flexible covering material on one face thereof.

5. A pad according to any preceding claim carrying a coating of an adhesive on the face opposite to any covering material.

6. A pad according to claim 1 substantially as illustrated in Figures 1 and 2 of the accompanying drawings.

7. An article of footwear including a pad according to any preceding claim.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (7)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Pad This invention relates to a pad for use in shoes, which comprises a foam material core with soft elastic properties and a thickness which decreases evenly towards its edges. Such a pad, covered with a surface material and coated on its underside with an adhesive, is commercially available and provides a reinforcement for use in shoes, especially for particular orthopaedic requirements. The core of pads of the type described, of a foam material, have an equivalent cell structure and, therefore, equal elastic properties in all regions. Such pads are therefore often unsuitable for the provision of equal support for all areas of a human foot, with its pred,ominantly rounded upper surface areas. For use in particular circumstances, such pads must be prepared individually. According to the present invention, a pad comprises a foam material core which contains closed, essentially spherical pores whose diameters decrease evenly towards its edges. In a pad according to the invention, the diameters of the spherical pores are largest in the area in which the foam material has its greatest thickness. The elasticity and, in particular, the elastic deformability of the pad is therefore greatest in this area, and these properties decrease evenly towards the edges of the pad. The outermost edges of the pad may be wholly free of pores and, in this case, the mechanical resistance at the edges is comparable to that of leather. A pad of the invention may comprise a polymeric material. The preferred material is a closed-cell, foamed, cross-linked polyolefin, and preferably a polyethylene, having a bulk density of 70 to 90 kg/m3. The maximum cell cross-section of such a material is about 0.8 mm. It may be prepared as a material width in a continuous process, provided on its upper face with a covering layer adhered thereto by flame-lamination, and subsequently formed into the desired shape. An adhesive may be applied to the opposite face. After heat treatment, a pad of the invention or a material width from which a pad is cut, may be embossed or otherwise formed. The pressure of the gas in the pores in the foamed material may thereby be increased as the pore size decreases towards the edges of the product. The strength of the pad therefore increases towards the edges thereof, and this is particularly desirable. The polyolefin foam is preferably chemically cross-linked to a degree of between 30 and 60%. If a pad of the invention is covered with a suitable covering material, this material is preferably a synthetic leather of fleece material polished on its outer face. Polishing removes fibre ends from the fleece material and causes fibres to stand out perpendicularly from its surface. The proud fibres serve to give a foot in contact with the material a sure hold. The invention will now be described by way of example with reference to the accompanying drawings, in which Figure 1 shows a pad embodying the invention in longitudinal crosssection, and Figure 2 shows the same pad in plan view. A foam material core 1 has pores whose cross-sections decrease evenly towards the edge zones thereof. The core has a flexible covering layer 2 on its upper surface and, on its underface 3, a layer of a reactive adhesive which is protected against drying by a covering film 4 of, for example, polyvinyl chloride. Figure 2 shows that the covering layer 2 covers the upper face of the foam material core completely. This allows for the provision of an even transition between the non-reinforced areas of a shoe and the soft elastic centre of the foam material core. A pad according to the invention may be used in heel or tongue reinforcements in articles of footwear, e.g. shoes. CLAIMS

1. A pad comprising a foam material, the pores of which are essentially spherical and whose cross-sections decrease evenly towards the edges of the pad.

2. A pad according to claim 1 in which the foam material is wholly free of pores at the edges thereof.

3. A pad according to claim 1 or claim 2 in which the foam material comprises a closed-cell foamed cross-linked polyethylene having a bulk density of 70 to 90 kg/m3.

4. A pad according to any preceding claim having a flexible covering material on one face thereof.

5. A pad according to any preceding claim carrying a coating of an adhesive on the face opposite to any covering material.

6. A pad according to claim 1 substantially as illustrated in Figures 1 and 2 of the accompanying drawings.

7. An article of footwear including a pad according to any preceding claim.