Fabric (woven – knitted – or nonwoven textile or cloth – etc.) – Coated or impregnated woven – knit – or nonwoven fabric which... – Coating or impregnation improves soil repellency – soil...
Reexamination Certificate
1999-12-15
2002-09-24
Morris, Terrel (Department: 1771)
Fabric (woven, knitted, or nonwoven textile or cloth, etc.)
Coated or impregnated woven, knit, or nonwoven fabric which...
Coating or impregnation improves soil repellency, soil...
C442S076000, C442S164000, C442S168000, C442S170000, C442S172000
Reexamination Certificate
active
06455447
ABSTRACT:
FIELD OF THE INVENTION
This invention generally relates to the field of paper making, and more specifically, to paper machine substrates.
BACKGROUND
Different types of pulp feedstocks may be used for making paper. Some feedstocks, such as recycled paper, often have contaminants. These contaminants include dirt and stickies. Stickies consist primarily of organic adhesives used in the paper converting industry, such as hot melts, pressure-sensitive adhesives, expanded polystyrene, and lattices. Generally, stickies include polyvinyl acetate polymers and copolymers, ethylene vinyl acetate polymers and copolymers, polystyrene, styrene-butadiene, polypropylene, polyethylene, polyamide, latex, other rubber compounds, and wax. A common source of stickies is the tackifiers added to paper products to improve adhesion properties.
Unfortunately, these stickies often adhere to the paper machine substrates, such as press felts, fabric sheets, and forming wires, that transport the pulp fibers during the paper making process. Once adhered to the paper machine substrate, the stickies may create holes in the substrate, and thus, may affect the quality of the produced paper. Furthermore, continued stickies deposition may require the replacement of the substrate, and thereby, increase production costs.
Accordingly a paper machine substrate that resists stickies adhesion will improve over conventional paper machine substrates.
DEFINITIONS
As used herein, the term “comprises” refers to a part or parts of a whole, but does not exclude other parts. That is, the term “comprises” is open language that requires the presence of the recited element or structure or its equivalent, but does not exclude the presence of other elements or structures. The term “comprises” has the same meaning and is interchangeable with the terms “includes” and “has”.
As used herein, the term “paper machine substrate” refers to a surface for transferring a layer of a different material, such as a fiber slurry or web. Examples of paper machine substrates include forming wires and press felts. Other examples of paper machine substrates include through-dryer, forming, and transfer belts as disclosed in U.S. Pat. No. 5,048,589, which is hereby incorporated by reference. Materials used to manufacture paper machine substrates include metals, such as steel or iron; mineral fibers, such as extruded glass or ceramics; natural fibers, such as wool; polymers; or mixtures thereof. Polymers used to manufacture substrates include polyolefins, such as polyethylene or polypropylene; polyamide polymers, such as nylon; and polyesters, such as polyethylene terephthalate; or mixtures thereof. Desired substrates can be made from woven polyethylene terephthalate or nylon, or alternatively, may be made from stapled substrates, such as woven polyethylene terephthalate sewn with nylon.
As used herein, the term “forming wire” refers to a screen belt or fabric on any wet-type paper machine. Liquid is drained from the pulp slurry deposited on the belt as the paper sheet is formed Forming wires may be made of materials including metals, mineral fibers, natural fibers, polymer fibers, or mixtures thereof.
As used herein, the term “press felt” refers to a continuous belt that performs as a conveyor or transmission belt of a pulp sheet, provides a cushion between press rolls, and serves as a medium for removal of liquid from the pulp sheet.
As used herein, the term “grafted” refers to the bonding, such as covalent bonding, of one material to another. An exemplary grafting technique chemically bonds organic polymers to a wide variety of other materials, both organic and inorganic, in the form of fibers, films, chips, particles, or other shapes.
As used herein, the term “active agent” refers to a substance that grafts or bonds to a paper machine substrate. Exemplary active agents include fluorinated monomers, fluorinated polymers, perfluorinated polymers, and polyalkyl siloxanes.
The term “machine direction” as used herein refers to the direction of travel of the forming surface onto which fibers are deposited during formation of a material.
The term “cross-machine direction” as used herein refers to the direction that is perpendicular and in the same plane as the machine direction.
As used herein, the term “woven” refers a network of crossed and interlaced material.
As used herein, the term “nonwoven web” refers to a web that has a structure of individual fibers which are interlaid forming a matrix, but not in an identifiable repeating manner. Nonwoven webs have been, in the past, formed by a variety of processes known to those skilled in the art such as, for example, meltblowing, spunbonding, wet-forming and various bonded carded web processes.
As used herein, the term “spunbond web” refers to a web formed by extruding a molten thermoplastic material as filaments from a plurality of fine, usually circular, capillaries with the diameter of the extruded filaments then being rapidly reduced, for example, by fluid-drawing or other well known spunbonding mechanisms. The production of spunbond nonwoven webs is illustrated in patents such as Appel, et al., U.S. Pat. No. 4,340,563.
As used herein, the term “meltblown web” means a web having fibers formed by extruding a molten thermoplastic material through a plurality of fine, usually circular, die capillaries as molten fibers into a high-velocity gas (e.g. air) stream which attenuates the fibers of molten thermoplastic material to reduce their diameters. Thereafter, the meltblown fibers are carried by the high-velocity gas stream and are deposited on a collecting surface to form a web of randomly disbursed fibers. The meltblown process is well-known and is described in various patents and publications, including NRL Report 4364, “Manufacture of Super-Fine Organic Fibers” by V.A. Wendt, E.L. Boone, and C.D. Fluharty; NRL Report 5265, “An Improved Device for the Formation of Super-Fine Thermoplastic Fibers” by K.D. Lawrence, R.T. Lukas, and J.A. Young; and U.S. Pat. No. 3,849,241, issued Nov. 19, 1974, to Buntin, et al., which are hereby incorporated by reference.
As used herein, the term “cellulose” refers to a natural carbohydrate high polymer (polysaccharide) having the chemical formula (C
5
H
10
O
5
)
n
and consisting of anhydroglucose units joined by an oxygen linkage to form long molecular chains that are essentially linear. Natural sources of cellulose include deciduous and coniferous trees, cotton, flax, esparto grass, milkweed, straw, jute, hemp, and bagasse.
As used herein the term “pulp” refers to cellulose processed by such treatments as, for example, thermal, chemical and/or mechanical treatments.
As used herein, the term “slurry” refers to a liquidity, such as watery, mixture or suspension of insoluble matter, such as pulp.
As used herein, the term “fiber” refers to a fundamental solid form, usually crystalline, characterized by relatively high tenacity and an extremely high ratio of length to diameter, such as several hundred to one. Exemplary natural fibers are wool, silk, cotton, and asbestos. Exemplary semisynthetic fibers include rayon. Exemplary synthetic fibers include spinneret extruded polyamides, polyesters, acrylics, and polyolefins.
As used herein, the term “weight percent” refers to a percentage calculated by dividing the weight of a material of a mixture by the total weight of the mixture and multiplying this quotient by 100.
As used herein, the term “percent add-on” refers to the percent of material added to a substrate after undergoing a treatment. The percent add-on is calculated by subtracting the pre-treatment weight (W
o
) from the dried post-treatment weight (W
t
) and dividing this difference by the pre-treatment weight (W
o
). This quotient is than multiplied by 100 to obtain the percent add-on. A formula for calculating the percent add-on is depicted below:
Percent Add-On
=
(
W
t
)
-
(
W
o
)
(
W
o
)
*
100
As used herein, the term “percent reduction in bond strength” refers to the percent reduction in maximum peel load by calculating the maximum peel load difference between a tr
Ross Russell Frederick
Yahiaoui Ali
Dority & Manning P.A.
Kimberly-Clark Corporation
Morris Terrel
Torres Norca L.
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