TECHNICAL FIELD The invention concerns a low density semifinished product for manufacturing buoyant products, comprising a plurality of layers of closed-cell expanded material, having a specific gravity lower than that of water, the said layers being flexible and elastic and being joined together by means of consecutive quilting spaced so as to define pockets of air between them to increase buoyancy.

BACKGROUND ART

Such a semifinished product, classified in the category of "non-woven fabric", is employed mainly for manufacturing items of clothing, such as jackets, overalls, items of clothing for specific uses, for fishing, sailing, or other activities, particularly for use in marine or aquatic environments in general, and for manufacturing objects aiding in natatorial activities, as well as bags, or holders in general for use in proximity to these environments and which require protection against the risk of sinking.

Conventional items of clothing that enable a person to remain afloat are most uncomfortable and do not allow the degree of agility of movement that would be preferable when carrying out working activities, or sporting activities, or other types of activities.

Furthermore, when manufacturing buoyant products in general, to obtain holders, covers, bags, or other items, a limitation has been found consisting of the fact that it is necessary to adopt special manufacturing processes which entail considerable costs. Also, the products obtained with

these processes turn out to be rigid and difficult to handle.

Such prior art may be subject to further improvements with a view to eliminating the said drawbacks. From the foregoing emerges the need to solve the technical problem of inventing a semifinished product that is suitable for manufacturing, in an extremely simple manner, buoyant products or that assist buoyancy, such as items of clothing, that are soft and easy to handle; in the case of clothing, these have to offer an adequate degree of buoyancy without excessively limiting freedom of movement.

DISCLOSURE OF THE INVENTION The invention solves the said technical problem by adopting a semifinished product of the type mentioned in the preamble characterised in that the quilting is preferably arranged in closed patterns.

This considerably improves the buoyancy in water of objects made with the semifinished product, in that it creates a series of pockets in which air is - so say - trapped, providing a more stable and long-lasting aid to buoyancy.

The closed patterns may also be obtained with cross quilting; in this case, the items of clothing manufactured with such a semifinished product have an improved wearability and are more comfortable. The cross quilting also confers a particular resistance to mechanical stresses to the semifinished product, especially during processing, in that it keeps the layers securely joined together.

As a resul of this invention it is possible to

manufacture buoyant products of pleasant appearance, substantially without imposing limitations on the creative impulse of fashion designers, in that the semifinished product may substantially be processed like a fabric and may be inserted in any type of item of clothing, or accessory, without compromising the look and/or the practicality of said item.

BRIEF DESCRIPTION OF THE DRAWINGS Some embodiments of the invention are illustrated, merely by way of non-limitative examples, in the accompanying drawings and wherein:

Figure 1 is a perspective view of a roll of material in superimposed quilted layers, partially unwound, constituting the semifinished product;

Figure 2 is a perspective view of a portion of semifinished product partially inserted in a lining in the form of a pocket;

Figure 3 is a view as in Figure 1, but with the semifinished product inserted between a pair of net elements to assist the quilting; Figure 4 is section IV-IV, partial and enlarged, of Figure 3;

Figures 5 to 25 show some examples of products manufactured using the semifinished product according to the invention, and show in order: Fig. 5 a handbag, Fig. 6 a tennis racket cover, Fig. 7 a belt bag, Fig. 8 a glasses case, Fig. 9 an envelope, Fig. 10 a wallet, Fig. 11 a fishing rod case, Fig. 12 a camera bag, Fig. 13 a vanity case, Fig. 14 a shoulder bag, Fig. 15 a bag with handles, Fig. 16 a travel bag, Fig. 17 a rucksack, Fig. 18 a

sleeveless jacket, for going fishing, Fig. 19 a waistcoat, Fig. 20 a jacket with integrated hood, Fig. 21 a jacket with removable hood, Fig. 22 a life jacket, Fig. 23 a jacket for learning to swim, Fig. 24 a short single-piece jacket for surfers; Fig. 25 a jacket and trousers combination. WAYS OF CARRYING OUT THE INVENTION The material for manufacturing buoyant products, in the form of non-woven fabric 1, wound onto a roll 2, comprises a plurality of layers 3, joined together, preferably by means of quilting, in a longitudinal direction 4 extending in the direction of the length of each layer 3 and in a traverse direction 5 perpendicular to the previous direction.

Each layer 3 is made of a material with a specific gravity lower than that of water, preferably an expanded material with closed compartments which, overall, is soft and very flexible; the thickness of each layer is approximately 1 mm.

Optimum results have been achieved with closed-cell expanded polyethylene.

The quilting 4, 5 joins two superimposed layers and define in the material 1 a plurality of closed areas, for example, squared, in which air is partially trapped for buoyancy and operating also as structural reinforcement.

Cross-quilting prevents the material for becoming excessively stiff. The material 1 may also be provided with a lining, particularly but not exclusively when manufacturing clothes.

Figure 2 shows how the material may also be inserted, in the direction indicated by arrow Fl, through an open side

7 of a lining 6 in the form of a pocket, so as to act as

padding for the said lining. This makes the manufacture of elements making up items of clothing and objects of various types and functions particularly simple to manufacture.

In general, the semifinished product may therefore act as padding in the manufacture of any type of object.

As shown in figure 3, the set of layers 3 may be sandwiched between a pair of net elements 8, joined to the sheets 3 by means of the same quilting 4, 5 that interconnects the sheets 3. The adoption of at least one flat net element 8 renders the semifinished product easier to work, in that the sheets are considerably easier to pull under the heads of the sewing machines.

Also, the net element prevents one or more of the sheets, that are made of a very soft material, from being cut by the thread used for the quilting. To this end, the net element 8 has to be very strong, but of reduced thickness, to prevent the product from becoming excessively rigid.

Experimental results have shown that items of clothing made with the semifinished product 1 are able to meet the most exacting safety regulations for nautical equipment.

It has also been found that the items of clothing made with this product provide excellent protection against wind, cold and atmospheric agents in general, in that they provide a high degree of thermal insulation. The material can therefore be used as padding for jackets, overalls, boots, in particular ski-boots.

In practice the materials, dimensions and details of execution may be different from, but technically equivalent to those described without departing from the scope of the

present invention.

For example, the type of stitching used for the quilting may vary in function of manufacturing requirements.