Brushing – scrubbing – and general cleaning – Implements – Adhesive lint remover
Reexamination Certificate
2000-04-26
2003-04-22
Till, Terrence R. (Department: 1744)
Brushing, scrubbing, and general cleaning
Implements
Adhesive lint remover
C015S209100, C015S231000, C428S138000
Reexamination Certificate
active
06550092
ABSTRACT:
BACKGROUND OF THE ART
Dust cloths for removing dust from a surface to be cleaned, such as a table, are generally known. Such known dust cloths may be made of woven or nonwoven fabrics and are often sprayed or coated with a wet, oily substance for retaining the dust. However, such known dust cloths tend to leave an oily film on the surface after use.
Other dust cloths utilize composites of fibers bonded together via adhesive, melt bonding, entanglement or other forces. To provide durable cloths, the staple fibers can be combined with some type of reinforcement, such as a continuous filament or network structure. Other cloths have attained the desired durability by employing fibers which are strongly bonded together, e.g., via adhesive bonding or melt bonding. While having good durability, such cloths may be less effective in their ability to pick up and retain particulates like dust and dirt.
Other known dust cloths include nonwoven entangled fibers having spaces between the entangled fibers for retaining the dust. The entangled fibers may be supported by a network grid or scrim structure, which can provide additional strength to such cloths. Cloths of this type can become saturated with the dust during use (i.e., dust buildup) and/or may not be completely effective at picking up denser particles, large particles or other debris.
Accordingly, it would be advantageous to provide cleaning sheets that can pick-up and retain debris. Such a cleaning sheet would preferably be capable of retaining relatively large and/or denser particles of debris while at the same time being very effective for picking up and retaining fine dust particles.
SUMMARY OF THE INVENTION
The present invention relates generally to cleaning sheets for use in cleaning surfaces, e.g., in the home or work environment. More particularly, the invention relates to a cleaning sheet for collecting and retaining dust, larger particles and/or other debris. The cleaning sheet includes a surface covered with a fabric material capable of picking up and retaining particulate matter and other debris, such as hair and lint. The outer surface of the fabric material includes a plurality of cavities therein. The cavities are typically larger relative to the particulate matter the cleaning sheets are designed to retain, e.g., commonly having a cross-sectional area of at least 3-4 mm
2
. The fabric material may optionally be treated with and/or incorporate therein a dust adhesion agent to enhance its effectiveness.
The cleaning sheet can include a fabric layer secured to a flexible backing layer so as to define an outer fabric surface with a plurality of cavities therein. The cavities commonly include a tacky surface. The cleaning sheet may include adhesive disposed between the fabric layer and the flexible backing layer. In such an embodiment, the fabric layer can have a plurality of apertures therethrough which expose at least a portion of the adhesive thereby forming cavities which have a tacky bottom surface. The present cleaning sheets generally have a breaking strength of at least 500 g/30 mm and an elongation at a load of 500 g/30 mm of no more than about 25%.
In another embodiment, the cleaning sheet has a first surface including a nonwoven fiber aggregate layer. A flexible backing layer is secured to the nonwoven fiber aggregate layer. The first surface has a plurality of cavities therein, which include a tacky surface capable of retaining particles, such as dust and dirt. The nonwoven fiber aggregate layer may be secured to the flexible backing layer by an intervening adhesive layer, e.g., a layer of pressure sensitive adhesive. A suitable nonwoven fiber aggregate layer is formed from a loosely entangled fibrous web which has a plurality of apertures therethrough. Such a fibrous web typically has a basis weight of 30 to 100 g/m
2
and a CD initial modulus (“entanglement coefficient”) of no more than 800 m.
As used herein, the term “entanglement coefficient” refers to the initial gradient of the stress-strain curve measured with respect to the direction perpendicular to the fiber orientation in the fiber aggregate (cross machine direction). The entanglement coefficient is also referred to herein as the “CD initial modulus.” Suitable nonwoven fiber aggregates for use in forming the present cleaning sheets have an entanglement coefficient of 20 to 500 m (as measured after any reinforcing filaments or network has been removed from the nonwoven fibrous web) and, more typically, no more than about 250 m.
Cleaning sheets according to one embodiment can be produced by coating an adhesive layer onto at least one surface of a flexible backing layer. A fabric layer, such as a nonwoven fiber aggregate layer having a plurality of apertures therethrough, can then be secured onto the coating of the adhesive. Alternatively, a composite material having a surface covered with a fabric layer with a plurality of cavities therein can have adhesive selectively applied to a surface within the cavities, e.g., by spraying a solution or dispersion of a pressure sensitive adhesive onto the bottom surface of the cavities. The fabric layer can be secured to a flexible backing layer by any of a number of conventional methods, e.g., via point melt bonding, adhesive bonding or stitching.
The entanglement coefficient (also referred to herein as “CD initial modulus”) as used herein is a measure representing the degree of entanglement of fibers in the fiber aggregate. The entanglement coefficient is expressed by the initial gradient of the stress-strain curve measured with respect to the direction perpendicular to the fiber orientation in the nonwoven fiber aggregate, i.e., in the cross machine direction (“cross direction” or “CD”). A smaller value of the entanglement coefficient represents a smaller degree of entanglement of the fibers. The term “stress” as used herein means a value which is obtained by dividing the tensile load value by the chucking width (i.e. the width of the test strip during the measurement of the tensile strength) and the basis weight of the nonwoven fiber aggregate. The term “strain” as used herein is a measure of the elongation of the cleaning sheet material.
The term “breaking strength” as used herein refers to the value of a load (i.e. the first peak value during the measurement of the tensile strength) at which the cleaning sheet begins to break when a tensile load is applied to the cleaning sheet.
As used herein, the term “elongation” refers to the relative increase in length (in percent) of a 30 mm strip of cleaning sheet material when a tensile load of 500 g is applied to the strip. The strip is elongated at a rate of 30 mm/min in the direction perpendicular to the fiber orientation (i.e, in the cross machine direction). As used herein the term “nonwoven fabric or web” means a web having a structure of individual fibers or threads which are interlaid, but not in a regular or identifiable manner as in a knitted fabric. The term also includes individual filaments and strands, yarns or tows as well as foams and films that have been fibrillated, apertured, or otherwise treated to impart fabric-like properties. Nonwoven fabrics or webs have been formed from many processes such as for example, meltblowing processes, spunbonding processes, and bonded carded web processes. The basis weight of nonwoven fabrics is usually expressed in ounces of material per square yard (“osy”) or grams per square meter (“gsm”). Fiber diameters useful are usually expressed in microns. Basis weights can be converted from osy to gsm simply by multiplying the value in osy by 33.91.
As used herein the term “microfibers” means small diameter fibers having an average diameter not greater than about 75 microns, for example, having an average diameter of from about 0.5 microns to about 50 microns, or more particularly, microfibers may have an average diameter of from about 2 microns to about 40 microns. Another frequently used expression of fiber diameter is denier, which is defined as grams per 9000 meters of a fiber and may be calculated as fiber diameter
Brown Colin W.
Francis Edward
LandOfFree
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