US 5,275,700 A · Papermaking belt and method of making the same using a deformable casting surface

Abstract

A backside textured papermaking belt is disclosed which is comprised of a framework and a reinforcing structure. The framework has a first surface which defines the paper-contacting side of the belt, a second surface opposite the first surface, and conduits which extend between first and second surfaces of the belt. The first surface of the framework has a paper side network formed therein which defines the conduits. The second surface of the framework has a backside network with passageways that provide surface texture irregularities in the backside network. The papermaking belt is made by applying a coating of photosensitive resinous material to the reinforcing structure and pressing the reinforcing structure into a deformable surface, so that the deformable surface forms protrusions which exclude resin from certain areas which when cured will lie along the backside of the belt, and then exposing the photosensitive resinous material to light of an activating wavelength through a mask which has transparent and opaque regions. A process for making paper products is also disclosed which involves applying a fluid pressure differential from a vacuum source through the belt to a partially-formed embryonic web of papermaking fibers. The fibers in the embryonic web are deflected into the conduits of the papermaking belt by the vacuum pressure while the papermaking belt and the embryonic web travel over the vacuum source. Following the deflection, the paper web is impressed with the paper side network of the belt, and dried to form the final product.

Claims25

Dependent claims

A papermaking belt having a paper-contacting side and a textured backside opposite said paper-contacting side, said papermaking belt comprising:

a framework having a first surface defining said paper-contacting side of said belt, a second surface opposite said first surface, and conduits extending between said first surface and said second surface, said first surface having a paper side network defining said conduits, said second surface having a backside network with passageways, distinct from said conduits, that provide surface texture irregularities in said backside network;
a reinforcing structure positioned between said first surface and at least a portion of said second surface, said reinforcing structure having a paper-facing side, a machine-facing side opposite said paper-facing side, interstices, a reinforcing component comprised of a plurality of structural components, a projected open area defined by the projection of the areas defined by said interstices, and a projected reinforcing area defined by the projection of said reinforcing component, wherein portions of some of said structural components are disposed inward of the plane defined by the machine-facing side of said reinforcing structure to form raised portions;
and
said passageways are disposed inward of the plane defined by the machine-facing side of said reinforcing structure, and a multiplicity of passageways are disposed between the plane defined by said machine-facing side of said reinforcing structure and said raised portions of said structural components, and said backside surface has sufficient fluid passage capacity to permit at least about 1,800 standard cubic centimeters/minute of air to escape across said textured surface.

1 more element

The papermaking belt of claim I wherein at least portions of a multiplicity of said passageways are positioned in said interstices so that a portion of the projected area of said passageways corresponds with a portion of the projected open area of said reinforcing structure.

A method of making a papermaking belt having a textured backside, said papermaking belt comprising a reinforcing structure and a resinous framework having a first surface, a second surface opposite said first surface, and conduits extending between said first surface and said second surface, said first surface having a paper side network formed therein defining said conduits, said second surface having a backside network with passageways, distinct from said conduits, that provide surface texture irregularities in said backside network, the method comprising the steps of:

(a) providing a forming unit with a deformable, constant volume, working surface;
(b) providing a reinforcing structure having a paper-facing side, a machine-facing side opposite said paper-facing side, interstices, and a reinforcing component comprised of a plurality of structural components, portions of some of said structural components being disposed inward of the plane defined by the machine-facing side of said reinforcing structure to form raised portions;
(c) bringing at least a portion of said machine-facing side of said reinforcing structure into contact with said working surface of said forming unit;
(d) pressing said machine-facing side of said reinforcing structure into said deformable, constant volume, working surface to cause portions of said working surface of said forming unit to deform and form protrusions between the plane defined by the machine-facing side of the reinforcing structure and some of said raised portions of said structural components and in some of said interstices;
(e) applying a coating of liquid photosensitive resin to at least one side of said reinforcing structure so that said coating substantially fills the void areas of said reinforcing structure and forms a first surface and a second surface, said coating being distributed so that at least a portion of said second surface of said coating is positioned adjacent said working surface of said forming unit, said paper-facing side of said reinforcing structure is positioned between said first and second surfaces of said coating, and the portion of said coating which is positioned between said first surface of said coating and said paper-facing side of said reinforcing structure forms a resinous overburden, wherein said protrusions in said working surface exclude portions of said coating along said second surface of said coating from some of the spaces which lie between the plane defined by the machine-facing side of said reinforcing structure and said raised portions and also from portions of at least some of said interstices to form excluded areas in said second surface of said coating which are defined by said protrusions;
(f) controlling the thickness of said overburden to a preselected value;
(g) providing a mask having opaque and transparent regions, said opaque regions together with said transparent regions defining a preselected pattern in said mask;
(h) positioning said mask between said coating of liquid photosensitive resin and an actinic light source so that said mask is in contacting relation with said first surface of said coating, said opaque regions of said mask shielding a portion of said coating from the light rays of said light source and said transparent regions leaving other portions of said coating unshielded;
(i) curing said unshielded portions of said coating of liquid photosensitive resin and leaving said shielded portions uncured by exposing said coating of liquid photosensitive resin to said light source through said mask to form a partially-formed composite belt;
and removing substantially all uncured liquid photosensitive resin from said partially-formed composite belt to leave a hardened resin framework around at least a portion of said reinforcing structure, which framework has a plurality of conduits in those regions which were shielded from said light rays by the opaque regions of the mask and passageways which provide surface texture irregularities in the backside network of said framework in those portions of said backside network which correspond to the places where the second surface of the coating was defined by the protrusions in the working surface of the forming unit.

7 more elements

(a) providing a forming unit which comprises a drum having a circular cross-section, said forming unit being provided with a deformable, constant volume, working surface;
(b) providing a reinforcing structure having a paper-facing side, a machine-facing side opposite said paper-facing side, interstices, and a reinforcing component comprised of a plurality of structural components, portions of some of said structural components being disposed inward of the plane defined by the machine-facing side of said reinforcing structure to form raised portions;
(c) applying a first coating of liquid photosensitive resin to at least said machine-facing side of said reinforcing structure to at least partially fill the void areas of said reinforcing structure;
(d) bringing at least a portion of said machine-facing side of said reinforcing structure into contact with said working surface of said forming unit;
(e) applying a second coating of liquid photosensitive resin to said paper-facing side of said reinforcing structure so that said first coating together with said second coating forms a single coating which has a first surface and a second surface and said coating substantially fills the void areas of the reinforcing structure, said coating being distributed so that at least a portion of said second surface of said coating is positioned adjacent said working surface of said forming unit, and said paper-facing side of said reinforcing structure is positioned between said first and second surfaces of said coating, wherein the portion of said coating positioned between said first surface of said coating and the paper-facing side of said reinforcing structure forms a resinous overburden;
(f) controlling the thickness of said overburden to a preselected value;
(g) pressing said machine-facing side of said reinforcing structure into said deformable, constant volume, working surface by tensioning said reinforcing structure so that forces are exerted by said reinforcing structure in directions normal to the working surface of said forming unit which press said machine-facing side of said reinforcing structure into said working surface causing portions of the working surface of the forming unit to deform and form protrusions both between the plane defined by the machine-facing side of the reinforcing structure and some of said raised portions of said structural components and in some of said interstices, so that said protrusions force portions of said coating along said second surface toward said raised portions thereby excluding portions of said coating from some of the spaces which lie between the plane defined by the machine-facing side of said reinforcing structure and said raised portions and also from at least some portions of said interstices to form excluded areas in said second surface of said coating which are defined by said protrusions;
(h) providing a mask having opaque and transparent regions, said opaque regions together with said transparent regions defining a preselected pattern in said mask;
(i) positioning said mask between said coating of liquid photosensitive resin and an actinic light source so that said mask is in contacting relation with said first surface of said coating, said opaque regions of said mask shielding a portion of said coating from the light rays of said light source, and said transparent regions leaving other portions of said coating unshielded;
(j) curing said unshielded portions of liquid photosensitive resin and leaving said shielded portions uncured by exposing said coating of liquid photosensitive resin to light having an activating wavelength through said mask to form a partially-formed composite belt;
and,
(k) removing substantially all uncured liquid photosensitive resin from said partially-formed composite belt to leave a hardened resin framework around at least a portion of said reinforcing structure, which framework has a plurality of conduits in those regions which were shielded from light rays by the opaque regions of the mask and passageways which provide surface texture irregularities in the backside network of said framework in those portions of said second surface of said resinous coating which were defined by the protrusions in said working surface.

9 more elements

Dependencies are inferred from the claim text.

Papermaking belt and method of making the same using a deformable casting surface

Life of this patent

Papermaking belt and method of making the same using a deformable casting surface

Life of this patent

Abstract

Claims25