Mat and method to manufacture mat

A method to manufacture mat, consisting of only three steps in order:

• first shaping:
• shaping a main body with a plastic material with a mold to form the main body of one piece, the main body at least having a first surface;
• cutting:
• cutting out a part of the main body to form a second surface which is wider than a thickness of the main body and is inclined to the first surface, a mean surface roughness of the second surface being different from that of the first surface;
• and
• second shaping:
• the first surface and the second surface under surface processing to vary the surface physical characteristics of the first and second surfaces and to lower the mean surface roughness of the second surface so that a third surface and a fourth surface are formed from the first surface and the second surface respectively and so that differences of mean surface roughnesses between the third and fourth surfaces are reduced to be smaller than differences of the mean surface roughnesses between the first and second surfaces, and an angle between the third surface and the fourth surface outside the main body being a specific value;
• wherein the plastic material is incompletely cross-bridged in the first shaping, and the plastic material is fully cross-bridged after the second shaping;
• wherein in the second shaping, the first surface and the second surface are heated and compressed with a second mold having at least one pattern to form the third surface and the fourth surface;
• wherein the main body is a foamed member, and after the step of cutting, a plurality of open cells are distributed on the second surface;
• wherein there are 150 to 250 of said open cells per square inch on the second surface, and after the first surface and the second surface are heated and compressed with the second mold, an area of the plurality of open cells distributed on the fourth surface is reduced to be at least less than 55% of an area of the plurality of open cells distributed on the on the second surface;
• wherein the area of the plurality of open cells distributed on the fourth surface is at least 15% of a total area of the fourth surface;
• wherein the open cell distributed on the fourth surface has a pore size greater than a pore size of the open cell distributed on the third surface;
• wherein the difference of the mean surface roughnesses of the third and fourth surfaces is less than or equal to 30%.