US 6,957,553 B2 · Method and line for the continuous stretching of hides and other similar products

Abstract

A method for the continuous wet stretching of industrial hides and other similar products comprises the following steps: a) removal of uniformly wetted hides following a treatment with liquids, such as tanning, re-tanning or the like, b) partial pre-drying of the wetted hides so as to reduce their residual relative moisture to a value of between 35% and 65%, c) stretching of the moist hides by means of localized mechanical stresses applied in directions which are substantially perpendicular to the plane of lie of the hides so as to achieve a predetermined increase in surface area, d) drying of the stretched hides until they have a residual relative moisture of between 7% and 30% so as to stabilize and thermally fix the stretched hides. The hides are kept in substantially constant relative humidity conditions with the mechanical stresses distributed uniformly over the entire surface area of the hides.

Claims16

Dependent claims

Method for the continuous wet stretching of industrial hides and other similar products, comprising the following steps:

a) removal of uniformly wetted hides following a treatment with liquids, such as tanning, retanning or the like;
b) partial pre-drying of the wetted hides so as to reduce their residual relative moistness to a value of between 35% and 65%;
c) stretching of the pre-dried hides by means of localised mechanical stresses, applied in directions substantially perpendicular to the plane of lie of the hides so as to achieve a predetermined increase in surface area;
d) drying of the stretched hides until they have a residual relative moistness of between 7% and 30% so as to stabilise and thermally fix the stretched hides;
characterized in that, during the stretching step c), the hides are kept in substantially constant relative humidity conditions and in that said mechanical stresses are distributed over the entire surface area of the individual hides in a substantially uniform manner without any constraining in their peripheral zones, so as to achieve substantially uniform radial stretching over their entire surface area.

2 more elements

Line for the continuous wet stretching of industrial hides for implementation of the method according to one or more of the preceding claims, comprising in succession:

means for transfer of the wetted hides (P) leaving a device (2) for treatment with liquids, such as a drum for tanning, retanning or the like;
machine (3) for the partial drying of the wetted hides (P) suitable for reducing their relative moistness to a value of between 35% and 65%;
a stretching machine (4) for the radial stretching of moist hides, in which said machine comprises stretching tools which act in directions substantially perpendicular to the plane of lie of the hides without retaining the peripheral edges thereof so as to perform a substantially radial and uniformly distributed stretching, and a pair of facing conveyer belts for feeding the hides, said belts being made of water-repellent materials selected so as to keep the moisture of the hides being processed substantially constant and prevent impregnation with the liquids contained in the hides during their mechanical stressing;
a machine (5) for drying and thermally fixing the stretched moist hides which is suitable for reducing their relative moistness to a value of between 7% and 30%.

1 more element

Dependencies are inferred from the claim text.

Method and line for the continuous stretching of hides and other similar products

Life of this patent

Method and line for the continuous stretching of hides and other similar products

Life of this patent

Abstract

Claims16