Process for bonding felts and needled felts

Claim 2

The process of claim 2, wherein during the heat-treatment and cooling steps the fiber blend is maintained at a predetermined distance from the conveying surface.

Claim 3

The process of claim 1, wherein after the heat-treatment step the fiber blend iS passed between cooling surfaces to obtain a uniform felt thickness.

Claim 4

The process of claim 1, wherein a fresh treatment medium is drawn into the heating chamber at the inlet thereof.

Claim 5

The process of claim 5, wherein the fresh treatment medium is air and is drawn into the heating chamber at the inlet and below the point at which the fiber blend is introduced into the heating chamber.

Claim 6

The process of claim 1, wherein the cooling down process is effected by ambient air, outside air or conditioned air which is drawn through the fiber blend.

Claim 7

The process of claim 1, wherein the fiber blend is subjected to a pressure treatment during at least part of the heating treatment.

Claim 8

The process of claim 1, wherein during the treatment process only one side of the fiber blend is contacted on the surfaces of the sieve drum.

Claim 9

The process of claim 1, wherein the fiber blend is conveyed through the heat-treatment step together with a humidified endless blanket and during said heat-treatment stage the water in said humidified blank is evaporated thereby producing a steam atmosphere, said steam being drawn through the fiber blend.

Claim 10

A continuous process for bonding and strengthening feltlike materials which comprises the following steps of adding about 10 to 70 percent of a synthetic bonding fiber to a feltlike material thereby forming a fiber blend, the sticking or melting point of the synthetic bonding fiber being about 100* to 300* C. and lower than that of the feltlike material, fuse-bonding said fiber blend by heating said blend on a sieve drum subjected to a suction draft, to the melting or sticking point of the synthetic fiber with hot air, steam, superheated steam or a steam-air mixture as the treatment medium, contacting the fiber blend with cooling surfaces to obtain a uniform felt thickness, and setting said fiber blend by cooling down the bonded fibers on a different sieve drum subjected to a suction draft, said heat-treatment and cooling down steps being effected shocklike in respective heating and cooling chambers by passing at least part of the heating and cooling treatment medium through said fiber blend.

Claim 11

The process of claim 11, wherein during the heat-treatment and cooling steps one surface of the fiber blend is supported on sieve drum means subjected to a suction draft.

Claim 12

The process of claim 12, wherein during the heat-treatment and cooling steps, the fiber blend is maintained at a predetermined distance from the conveying surface.

Claim 13

The process of claim 11, wherein the feltlike material is selected from the group consisting of natural fibers, synthetic fibers, glass fibers and metallic fibers.

Claim 14

The process of claim 11, wherein the feltlike material is wool and the synthetic bonding fiber is polypropylene.

Claim 15

The process of claim 11, wherein the feltlike material is glass fiber and the synthetic bonding fiber is the condensation product of hexamethylenediamine with adipic acid.

Claim 16

The process of claim 11, wherein the feltlike material is polyethylene terephthalate and the synthetic bonding fiber is the polycondensation product of caprolactam.

Claim 17

The process of claim 12, wherein the fiber blend is compressed against the surface of the sieve drum during the heating step by a wire mesh belt thereby effecting a better bonding of the fiber points in the fiber blend.