Mats used in wet areas, particularly in shower spaces, are requested to have certain desirable properties.

Obviously, most important of these are good resistance to moisture, fast drying, comfortable feel under the feet and sufficient friction to prevent slipping. From the prior art are known a plurality of different kinds of mats for wet areas, one of the most popular brands being marketed under the trade name SYMPATEX. These mats are made by soaking a glass-fiber fabric in a PVC suspension and then foaming the plastic. As a result, a mat offering a comfortable feel to the feet and a sufficient friction is obtained, however, with a drawback of water absorbance due to its open-pore cell structure. Hence, the mat dries slowly and its drying requires the mat to be hanged in a proper place, where water can be drained off from the mat. If the mat is left, e. g., on the bathroom floor after its use in the shower, both the mat itself and the space between the mat and the floor will remain soaked with water, whereby no essential drying can occur. Thus used, the mat also becomes unhygienic.

Also known in the art are wet-area mats made with an open-mesh structure from a harder grade of plastic. While these mats dry fast, they feel uncomfortable under the feet due to their hardness.

It is an object of the present invention to provide a method of producing a mat for wet areas, whereby a mat produced according to the method is free from the above- described problems. The goal of the method according to the invention is achieved by virtue of a process com- prising forming a blank containing polyolefin polymer, particularly polyethylene, a foaming agent and a cross-

linking agent, heating said blank in an oven, whereby it undergoes foaming and crosslinking, and compressing the product in a press or similar mould into a desired shape, either during the heating step or immediately thereafter.

A mat made according to this method has the benefit of a closed-cell structure in its material, which prevents water from penetrating into the mat material. Further- more, the mat material is sufficiently soft to feel comfortable and warm as well to the feet. Because the material is nonabsorbent to water, it also stays more hygienic than most known types of mats owing to its significantly faster and easier drying. The material is also user-friendly, because there is no need to hang it for drying after each cycle of use.

Some preferred embodiments of the invention are specified in dependent claims 2-6.

In the following the invention will be examined in greater detail with reference to the appended drawings, in which Figure 1 is a top view of a portion of the mat imple- mented as an embodiment of the invention; Figure 2 is a sectional view along the line II-II of Fig. 1; and Figure 3 is a sectional view along the line III-III of Fig. 1.

The wet-area mat 1 shown in Fig. 1 is produced by virtue of the method according to the invention. The mat surface has upward-projecting tops 2 with vertical and horizontal channels made thereinbetween in order to enhance water drainage off from the mat. In Fig. 1, the tops 2 are drawn covering only a fraction of the mat surface. In

practice, however, the entire surface of the mat is cov- ered with upward-projecting tops. The shape of the tops can be selected freely as they are nonessential to the function of the invention except for said drainage.

In the method according to the invention, the mat blank is first prepared from a mixture containing a polyolefin polymer, a foaming agent also called an expanding agent and a crosslinking agent such as a peroxide. One of the most suitable polyolefins grades for use in the invention is polyethylene. The mixture thus prepared is heated in an oven adapted for the process. The foaming agent can be selected from the group of compounds known to decompose at an elevated temperature and to release simultaneously gaseous components. The volume of gases thus released will be manyfold as compared to the volume of the starting materials. The gases normally released contain chiefly nitrogen, carbon dioxide and carbon monoxide. The decomposition reactions of the crosslinking agent such as a peroxide and the foaming agent occur at different temp- eratures. It is essential that the properties of the starting material components are matched so that the reactions can be carried out in correct order at desired temperatures. Crosslinking in the polymerization process refers to the intermolecular bonding of thin, linear polymer molecules to each other into a three-dimen- sionally solid network of linked polymer backbone chains.

After or during the heating and crosslinking steps, the desired pattern of stops will be pressed on the mat blank (with the flow channels and the tops 2). The pressing equipment may comprise, e. g., two closely running rolls of which at least the one pressing the top side of the mat is contoured to form the desired top texture of the mat. In addition to the running channels and tops, the mat is advantageously provided with holes 4 arranged at suitable spacings, e. g., into rows as shown in Fig. 1.

Owing to the holes, water will be drained from the space between the mat and the floor and, correspondingly, moisture can escape to the environment from said space, thus permitting faster drying of the mat, whereby improved hygienics of the mat results.

Finally, the underside of the mat can be provided with a layer 3 of an antislip material thus assuring good stay of the mat in place. Such antislip backing can be made from any material of a high coefficient of friction that is suitable for use in wet areas. An alternative approach is to contour the underside of the mat during its pressing step with"bumps"of a relatively small top area which, resultingly, will be subjected to a rather high surface pressure that increases the friction.

To those versed in the art it is obvious that the inven- tion is not limited by the exemplifying embodiments described above, but rather, may be varied within the scope and spirit of the appended claims.