KR100662582B1 - Particle entrapment system - Google Patents

Abstract

The present invention relates to a cleaning sheet for cleaning a surface to remove particles from the surface. The cleaning sheet includes a particle retaining layer for collecting and retaining particles. The particle retaining layer comprises electret wax deposited on at least a portion of the layer.

Surface, cleaning, particle, sheet, electret, wax

Description

Particle Capture System {PARTICLE ENTRAPMENT SYSTEM}

In general, the present invention relates to a cleaning sheet for use in, for example, cleaning a surface in a home or work environment. More specifically, the present invention relates to the field of cleaning sheets for collecting and maintaining large particles and / or other debris.

Generally, a dust cloth for removing dust from the surface to be cleaned is known. Typically, this known dust removal cloth consists of a woven or nonwoven fabric, often sprayed or coated with a damp oily material to hold the dust. However, such known dust removal cloths can leave an oily film on the surface after use.

Other known dust removal cloths are non-woven entangled fibers, with spaces formed between them to form dust. Typically, the entangled fibers are supported by a network grid or scrim structure that can provide additional strength to the fabric. However, such fabrics may be saturated with dust (ie, dust accumulation) in use and / or may not be completely effective in capturing dense particles, large particles or other debris.

Therefore, it would have been beneficial to provide a cleaning sheet capable of capturing and retaining dust and debris. It would also be beneficial to provide a cleaning sheet with improved dust collection capabilities. It would also be beneficial to provide a cleaning sheet that pulls debris away without using oily sprays. It would also be beneficial to provide a cleaning sheet that holds relatively large and / or dense particles of debris. It would also be beneficial to provide a cleaning sheet that includes one or more of these or other beneficial features.

In general, the present invention relates to a cleaning sheet for use in, for example, cleaning a surface in a home or work environment. More specifically, the present invention relates to the field of cleaning sheets for collecting and maintaining large particles and / or other debris.

A particle entrapment system or cleaning sheet is provided. The cleaning sheet is useful for cleaning and removing particles or other debris from the surface of tables, hardwood floors, furniture products, and the like. The cleaning sheet may be provided with multiple layers or sheets for increasing debris retention and / or strength. Typically, the sheet has a particle retaining layer containing an electret material for collecting and retaining particles. The electret material is an electret wax that precipitates and / or impregnates at least a portion of the particle retaining layer.

In addition, the sheet may have an outer layer (eg, a cover layer) covering at least a portion of the particle holding layer. The cover layer may have a plurality of holes that can capture and / or attract debris. The holes may constitute a substantial part of the cover layer and may typically have a cross-sectional area of at least about 1.0 mm ² . An example of a suitable cover layer is a material having a plurality of holes of an average cross-sectional area of about 1.0 to about 10.0 mm ² . Generally, the cover layer is made of a material having low dust retention (for example, a perforated sheet made of polytetrafluoroethylene). The cover layer is made of a low dust holding material and has a plurality of through holes.

Furthermore, a cleaning tool provided with the cleaning sheet is provided. The cleaning tool may have a cleaning head suitable for connecting to the cleaning sheet. The cleaning sheet (s) may be packaged as part of a cleaning utensil kit for cleaning the surface. The kit may have a cleaning head suitable for connecting to the sheet and a handle for connecting to the cleaning head.

Also provided are methods for cleaning the surface. The method includes contacting the surface to be cleaned with the cleaning sheet. Debris on the surface to be cleaned can be attracted to the particle holding layer and held in the cleaning sheet.

In many embodiments of the cleaning sheet, the particle retaining layer may be a cover layer, a backing sheet or a backing layer or a core layer. The particle holding layer may be a uniform flat sheet or a contour surface having protrusions and depressions. Typically, an electret material, such as waxed electret, is deposited or impregnated in at least a portion of the particle retention layer in order to improve particle collection and / or retention capacity of the particle retention layer.

Also provided is a method of manufacturing a cleaning tool for collecting and retaining debris. The method includes forming a particle retaining material such as woven fiber, or nonwoven fiber and / or foam. The method includes applying a non-electret wax to at least a portion of the particle retaining material. At least an electric field is applied to the sheet to induce permanent charge in the wax. Generally, this is accomplished by heating the sheet to a temperature sufficient to melt the wax without actually softening the particle retaining material. While the wax is in the molten state, an electric field is applied to the sheet. The electric field has a size and duration sufficient to electrically charge the wax. For example, this can be accomplished by corona discharge of the sheet with the molten wax. The charged wax is then cooled and solidified to charge relatively permanently.

In addition, the sheet of the present invention may be formed by applying an electric field to the molten wax as the molten wax is applied to the particle holding layer. For example, molten wax may be sprayed onto portions of the layer of particle retaining material in a continuous or discontinuous pattern such that the wax remains molten as it passes through the electric field. In general, it is advantageous to maintain the particle retaining material at a sufficiently low temperature so that the wax solidifies upon or immediately after contact with the particle retaining material.

Typically, the cleaning sheet has a relatively low overall breaking strength in order to preserve the relative amount of flexibility. As used herein, the term “break strength” means a load value at which the cleaning sheet begins to break when a tensile load is applied (ie, the first peak value at the time of tensile strength measurement). However, the breaking strength of the sheet should be high enough to prevent shedding or tearing of the cleaning sheet in use. Typically, the breaking strength of the cleaning sheet is at least about 500 g / 30 cm, and cleaning sheets having breaking strengths of 1,500 g / 30 cm to 4,000 g / 30 cm are suitable for use with the cleaning tools described herein.

When intended for use with a cleaning tool or mounting structure or the like, typically the cleaning sheet has a relatively low overall elongation to help inhibit bunching or pucking. As used herein, the term "elongation" refers to the percent elongation of the cleaning sheet when a tensile load of 500 g / 30 mm is applied. For example, when intended to be used with a mop or similar cleaning tool to which the cleaning sheet is fixedly mounted, the cleaning sheet of the present invention typically has an elongation of about 25% or less, preferably about 15% or less. Have

As used herein, the terms "surface" and "surface to be cleaned" are broad terms and are not intended to be used in limiting terms. This term “surface” includes substantially hard or hard surfaces (eg, furniture products, tables, shelves, floors, ceilings, hardened furniture, household utensils, etc.), and relatively softer or more semi-hard surfaces (eg, rugs). , Rugs, soft dry bulbs, linens, clothing, etc.).

As used herein, the term "debris" is in a broad sense and is not intended to be used in a limiting term. In addition to dust and other particulate matter, the term debris, which cannot be collected by conventional dust rags, such as large sized dirt, food particles, crumbs, soil, sand, cotton chips, fiber debris and hair, In addition to relatively large sized particulate materials having an average diameter of at least 1 mm, dust and other particulate materials are included.

Herein, various embodiments of the cleaning sheet and / or method of using or forming the same are described. The various embodiments described herein are for illustrative purposes only and are not meant to limit the scope of the invention. The various embodiments described herein are for the purpose of providing various examples, and the descriptions of the various embodiments may have overlapping scope and are not necessarily construed as various modifications.

1 is a perspective view of a cleaning tool according to an exemplary embodiment.

2 is a cross-sectional view of the cleaning sheet taken along line 2-2 of FIG. 2 in accordance with an exemplary embodiment.

3 is a fragmentary partially disassembled assembly cross-sectional view of a cleaning sheet according to another exemplary embodiment.

4 is a fragmentary partially disassembled cross-sectional view of a cleaning sheet according to another exemplary embodiment.

5 is a fragmentary partial disassembly cross-sectional view of a cleaning sheet according to another exemplary embodiment.

6 is a plan view of a scrim of a cleaning sheet according to a suitable embodiment.

7 is a fragmentary plan view of a cleaning sheet according to a suitable embodiment of the present invention.

8 is a fragmentary plan view showing holes in a cleaning sheet according to a suitable embodiment of the present invention.

9 is a stress strain curve, where the vertical axis represents stress, the horizontal axis represents strain, and O represents the origin.

10 is a cross-sectional view of an apparatus for imparting electrets to wax.

FIG. 11 is a cross-sectional view of electret wax formed using the apparatus shown in FIG. 10.

12 is a cross-sectional view of a cleaning sheet having an electret layer and a microfiber layer.

13 is a plan view of a cleaning sheet comprising electret wax distributed in a discontinuous pattern.

14 is a cross-sectional view of a cleaning sheet comprising electret wax distributed in a pattern of strings.

FIG. 15 is a cross-sectional view of the cleaning sheet of FIG. 3 showing electret wax deposited in a depression of the particle holding layer. FIG.

One example of a cleaning sheet for collecting, attracting, and retaining particulate matter and other debris (eg, dust, dirt, other airborne materials, cotton debris, hair, etc.) is illustrated in FIG. 1 by a dusting pad; 10). The pad 10 is intended to attract (eg, collect) and retain particulate material (shown as debris 68 in FIG. 2) and is a "electret" base or core particle that is permanently charged with electrostatic force. The holding layer 30 is provided. Debris 68 is attracted into the particle retaining layer 30 as the pad 10 moves along the surface to be cleaned (shown as working surface 66 in FIG. 1). The voids (shown as cavity 34) of the core 30 retain and / or capture debris 68 in the cavity 32 of the pad 10 (see, eg, FIG. 2).

The particulate material may also be retained by a cover sheet that can cover or wrap all or part of the electret material in order to capture and retain it in the electret material. The outer or cover layer 20 may be made of a material having a relatively low debris retention force (ie, does not attract or collect significantly debris), and generally has a lower debris retention force than the core so that the cover layer 20 The outer surface of) is maintained with virtually no debris 68. An example of an exemplary material that does not attract significantly dust is a perforated sheet of polytetrafluoroethylene. Typically, the cover sheet is configured to hold at least about 10 g / m ² particulate material, more suitably about 1 to 5 g / m ² particulate material.

1. Particle retention layer

The cleaning sheet of the present invention has a particle retaining layer, at least a portion of which is an electret material (ie, permanently electrically charged). The sheet has a core 30 comprising a particle retaining layer 32 located within the pad 10 adjacent to the cover layer 20. In other embodiments, the cleaning sheet may simply consist of a particle retaining layer (eg, a scrim-support layer of a nonwoven microfiber and at least a portion of the support layer coated with electret wax). The cavity 34 of the particle holding layer 32 captures, collects and holds a considerable amount of debris 68. For example, debris can be buried in contact with the walls of the cavity. According to a suitable embodiment, the particle retaining layer may be a molded fabric, a continuous sheet of flexible material, or multiple sheets of material. Referring to FIG. 2, the cavity 34 may consist of voids distributed irregularly in the core 30. As shown in FIG. 2, the cavity 34 may have a rounded shape, a sawtooth shape, an irregular shape, or a combination of the above shapes in addition to the circular shape. For example, the cavity may have a rectangular shape, a star shape, an ellipse shape, or an irregular shape. As shown in Fig. 3, the cavities may be arranged in a regular pattern and arranged irregularly.

The size and depth of the cavity is preferably large enough to form a “pocket” or cavity of sufficient size so that captured debris does not scratch or damage the surface being cleaned. However, it is desirable that the cavity is not so deep that debris is difficult to contact the cavity. Typically, the cavity has an average width of about 1 to 10 mm, more suitably 2 to 5 mm, depending in part on the size of the particles to be maintained. The cavity typically has an average depth of about 0.1 to 5 mm, more suitably 1 to 3 mm.

3 shows a cross section of pad 110, which is an exemplary embodiment of a cleaning sheet. The pad 110 is substantially different from the pad 10 in that the structure of the core 30 is changed. In addition to these modifications, the structure, performance, and function of the pad 110 shown in FIG. 3 are substantially the same as the pad 10, and the same reference numerals are used to denote the same elements. The core 130 of the pad 110 is configured to form a void, shown as the depression 134. The protrusions, shown as fingers 136 extending outwardly and flexible, extend from the core 130 toward the cover layer 20. Fingers 136 generally have a rectangular shape, but may also have other shapes (eg, zigzag, round, wave, etc.), depending on other implementations. The fingers 136 are arranged in a string-shaped pattern, but may be arranged in other patterns or shapes (eg, circular, random, etc.), depending on other suitable implementations. Finger 136 defines a depression 134 for retaining debris 68 between two protrusions. When retained in the depression 134, the crush 68 is substantially prevented from escaping from the interior of the pad 110 by the cover layer 20.

4 shows pad 210, which is another exemplary embodiment of a cleaning sheet. The pad 210 is substantially different from the pad 10 in two respects: the structure of the core 30 changes and the material of the core 30 changes. In addition to these variations, the structure, performance, and functionality of the pad 210 are substantially the same as the pad 10, and like reference numerals are used to denote like elements. The core 230 of the pad 210 has a shape such that an air gap (shown as the depression 234) for holding the debris 68 is formed. The upper cover layer 20 is interposed between the lower cover layer 20 and the core 230. The depression 234 is formed by the protrusion 236 extending from the core 230. The protrusion 236 is generally blunt and includes an inclined wall 240. The inclined wall of the protrusion 236 provides additional surface area for the depression 234 for collecting and retaining debris 68. As shown in Figure 4, the protrusions 236 are arranged in the form of a string or wavy. The protrusions 236 of the upper particle retaining surface 232 are shown arranged in an alternating fashion to correspond to the depression 234 of the lower particle retaining surface 238. According to another suitable embodiment, the protrusions and voids (ie, depressions) may be arranged in various other forms (eg, the protrusions of the upper particle retaining surface correspond to the protrusions of the lower particle retaining surface). Arranged in a shape or wave shape). According to another suitable embodiment as shown in FIGS. 4 and 5, the particle retaining layer (ie, core) has at least two sides, and voids (ie, cavities) are present on each side of the particle retaining layer. Are arranged.

5 shows pad 310, which is another exemplary embodiment of a cleaning sheet. The pad 310 is substantially different from the pad 10 in that the structure of the core 30 changes and the material of the core 30 changes. In addition to these changes, the structure, performance, and functionality of the pad 310 are substantially the same as the pad 10, and like reference numerals are used to denote like elements. The core 330 of the pad 310 is shown to consist of an entangled net structure of nonwoven fibers. The pores for trapping debris consist of the space between the entangled fibers (ie, debris is retained between the fibers making up the core). According to another suitable embodiment, the core may be composed of various combinations of materials formed of various structures.

As used herein, the term "non-woven" includes a web having a structure in which individual fibers or yarns are sandwiched between them rather than in a regular or identifiable form as in knitted fabrics. The term also encompasses foams or films, in addition to including individual filaments and strands, yarns or tows, having fine fibers, perforations or otherwise treated to impart fabric-like properties. Nonwoven fabrics or webs have been formed using many methods, such as the meltblowing process, the spunbonding process, and the bonded carded web process. In general, the basis weight of a nonwoven is expressed in ounces per cubic yard ("osy") or grams per cubic meter ("gsm") of the material, and the useful fiber diameter is osy simply by multiplying the value of osy by 33.91. Can be converted into gsm. According to another suitable embodiment, the fibers may be woven.

According to an exemplary embodiment, a web or lattice (shown as scrim 50 in FIG. 6) may support the fibers of the nonwoven sheet. Thus, it is possible to produce a sheet having a relatively low entanglement coefficient (eg, 800 m or less) while maintaining sufficient strength for use in cleaning. As shown in FIG. 5, a scrim may be integrally fitted into the fiber to form one support structure. In FIG. 6, the scrim 60 comprises a net having a horizontal component 52 attached to a vertical component 54 arranged in a network structure. In order to impart a mash or lattice structure to the scrim 50, a space (shown as a hole 56) is formed between the vertical component 54 and the horizontal component 52. According to various implementations, the horizontal or vertical components of the scrim may be connected together in various ways, such as woven, spot welded, cinched, or tied. . In general, the diameter of the hole 56 is 20 to 500 mm, more preferably 100 to 200 mm. Typically the distance between the fibers is about 2 to 30 mm, more suitably about 4 to 20 mm. Alternatively, the nonwoven sheet may be reinforced with a filament embedded in the sheet that is held in place by a mechanical force obtained by simply hydroentangling microfibers around the filament.

The fibers may be placed on each side of the scrim 50 and attached to the scrim 50 to form the pad 310 as a single species or structure. A low-pressure water jet may then be used to entangle the fibers with each other and with the scrim 50 (ie, hydraulic weaving) to form a relatively loose entanglement of nonwoven fibers. Hydraulic entanglement of the fibers can be increased even more during removal of water from the water jet (eg, drying). The scrim may also shrink to some extent during drying to obtain a fabric having wrinkled or contoured surfaces. The fibers may also be attached to the web (ie, scrim) by various other conventional methods (eg, air laid, adhesive, woven, etc.). Typically, the fibers are entangled on the web to form a monolith that helps prevent peeling of the fibers from the web upon cleaning. The web may be made of various materials such as polypropylene, nylon, polyester, and the like. Representative webs (ie, scrims) are described in US Pat. No. 5,525,397, the disclosure of which is incorporated herein by reference.

The degree of entanglement of the fibers in the core can be measured by the "entanglement coefficient". The entanglement coefficient is also referred to as "CD initial modulus." The term "entanglement coefficient" as used herein refers to the initial slope of the stress-strain curve measured about the direction perpendicular to the fiber orientation (cross machine direction) in the fiber assembly. As used herein, the term "stress" refers to a value obtained by dividing the tensile load value by the chucking width (ie, the width of the test strip when measuring tensile strength) and the basis weight of the nonwoven fiber assembly. As used herein, the term “strain” refers to the elongation value of a cleaning sheet material.

The nonwoven fiber aggregate suitable for use in forming the cleaning sheet has a entanglement coefficient of about 20 to 500 m, preferably about 250 m or less, as measured after removal of any reinforcing filaments or networks from the nonwoven fiber web. In general, the smaller the value of the entanglement coefficient, the smaller the degree of entanglement of the fiber. The entanglement coefficient can be controlled in part by selecting the type and amount of fiber, the weight of the fiber, the amount and pressure of water (line 52 to column 5 in column 4 of US Pat. No. 5,525,397, which describes the fiber entanglement). Up to 26).

The core (eg, core 330 shown in FIG. 5) may comprise a nonwoven aggregate having fibers of high degree of freedom and sufficient strength as may be advantageous for effectively collecting and retaining dust and larger particulates in the cleaning sheet. have. In general, nonwovens formed by entanglement of fibers involve higher degrees of freedom of constituent fibers than nonwovens formed only by melting or attachment of fibers. The nonwoven fabric formed by the entanglement of the fibers may exhibit better dust collection performance through the entanglement between the dust and the fibers of the nonwoven fabric. In other words, if the entanglement is too strong, the degree of freedom of the fiber for movement is reduced and the holding force of the dust is reduced. In contrast, if the entanglement of the fibers is too weak, the strength of the nonwoven can be significantly lowered and thereby the processability of the nonwoven can be a problem. In addition, the peeling of fibers from the nonwoven can occur even more in the case of nonwoven aggregates having a very low degree of entanglement.

Nonwoven assemblies suitable for use in making the cleaning sheets of the present invention can be formed by hydro weaving fiber webs (with or without support filaments or network sheets) under relatively low pressure. For example, carded The fibers of the carded polyester nonwoven web can be sufficiently entangled with the network sheet by treating the nonwoven fiber web with water sprayed at high speed under a pressure of about 25 kg / cm ³ . Water may be ejected from orifices located on top of the web as it passes through a substantially flat nonporous support drum or belt. Typically, the orifices may have a diameter of 0.05 to 0.2 mm and may be arranged in line below the water supply line at intervals of 2 m or less.

When the entanglement coefficient of the fiber aggregate is set to a value of up to about 800 m, a sheet composed only of the fiber aggregate may be difficult to achieve values of sufficient fracture strength and elongation. By entangling the fibers with the scrim 50 to form a monolith, the elongation of the layer can be kept low and its processability can be improved. Peeling of the fibers from the cleaning sheet is significantly prevented as compared to conventional entangled sheets consisting of only fiber aggregates present in the same entangled state.

If the entanglement coefficient is too small (eg about 10-20 m), the fibers will not be entangled enough with each other. In addition, the entanglement between the fiber and the scrim is insufficient. Thus, peeling of the fibers can often occur. If the entanglement coefficient is too large (eg, about 700 to 800 m), sufficient degrees of freedom of the fibers cannot be obtained because the entanglement is too strong. Thus, the fibers can be easily entangled with dust, hair and / or debris, and the cleaning performance of the sheet may be unsatisfactory.

Typically, the cleaning sheet comprises a non-woven fiber aggregate as a core layer having a relatively low basis weight. Generally, the basis weight of the nonwoven fiber aggregate is 30 to 100 g / m ² , typically 75 g / cm ^{2 or less} . If the basis weight of the nonwoven fiber assembly is about 30 g / m ² or less, the dust may pass too easily through the nonwoven fiber assembly in the cleaning operation and its dust collecting capacity may be limited. If the basis weight of the nonwoven fiber assembly is too large (eg, greater than or equal to about 150 g / m ² ), the fibers in the nonwoven fiber assembly generally cannot be sufficiently entangled with each other to achieve the desired degree of entanglement. In addition, the processability of the nonwoven fiber assembly may deteriorate, and peeling of the fiber from the cleaning sheet may occur more frequently. The denier of the fibers in the nonwoven fiber assembly, the length, the cross-sectional shape and the strength of the fibers used in the nonwoven fiber assembly are generally determined in consideration of workability and cost, in addition to factors relating to performance.

Typically the cleaning sheet has an outer nonwoven fibrous layer or net / web having a relatively low basis weight as the outer fabric layer (ie, the material on the cleaning surface of the sheet). According to a particularly suitable embodiment, the nonwoven layer or net has a basis weight of about 20 to 150 g / m ² , preferably of 30 to 75 g / m ² .

The cleaning sheet may have a nonwoven fabric made of fibers or microfibers. The term "denier" as used herein is defined as the weight in grams of 9000 meter long fibers. The denier of the fibers of the particle retaining layer is preferably about 0.1-6, more preferably about 0.5-3.

a. Electrostatic Characteristics of Particle Retention Layer

The particle retention layer may comprise a dielectric material that may be, in whole or in part, an electret. Electrets are those that maintain a static charge over a long period of time (for example, years). Electrets are believed to be relatively permanent sources of electric or electrostatic fields. Thus, by making the dielectric material an electret in a cleaning sheet (eg, a particle holding layer, a cover layer, a backing layer, etc.), static charges may accumulate on the cleaning sheet. This build-up of static charge causes the cleaning sheet's ability to attract, collect, capture, and retain debris during the cleaning process, only to be in physical contact with the debris as it is attached to or encased in a conventional non- electret material. Compared with the conventional non- electret material, it can improve.

Applying an external electric field can make the dielectric material an "electret." The molecules and charges in the dielectric are polarized or oriented in a particular direction or moment. The resulting electrets are believed to have electric internal volume polarization which generates a permanent electrostatic field. The opposing outer surfaces of the electrets exhibit opposite electrostatic charges. As the outer surface molecules and charges as well as the inner molecules and charges are polarized, the electrostatic orientation extends over the entire electret. Thus, multiple electrets are obtained by breaking or splitting the electret (e.g., similar to the destruction of permanent magnets).

The electret of the dielectric material involves heterocharge, homocharge, or both depending on the dielectric starting material and the method of preparation. As used herein, "isotype charge" is a charge on a dielectric of the same sign as the polarity of a neighboring forming electrode. The forming electrode applies an electric field to the dielectric to make the dielectric an electret. Isoelectric charges are believed to occur frequently in compounds containing esters and / or alcohols. As used herein, “release charge” is the charge on a dielectric of a sign opposite to the polarity of the forming electrode. Representative charges are typically unstable. After the electric field is applied by the forming electrode, the charge amount of the heterogeneous charge decreases until a polarity reversal occurs to reach an apparent equilibrium. The resulting electret has a surface charge (i.e. isotype charge) having the same polarity as the corresponding forming electrode.

i. Wax electret

The wax can be an electret. Wax in an electret or non- electret state may be applied to the cleaning sheet. One way to make the wax an electret is to: According to one method, a suitable wax in the molten state (shown as paraffin 400 in FIG. 10) is injected into a condenser or mold (flat brass dish 402 covered with a wrap shown as tin foil 404). A heater (shown as gas burner 406) may promote melting of paraffin 400. Particularly desirable results are obtained when paraffin 400 melts to the full fluid state upon application of the electric field. According to a variant, the electret can be formed without melting the wax. In this embodiment, the wax is generally heated so that a softened state is obtained prior to exposure to the electric field.

As paraffin 400 cools (eg, to about room temperature) and solidifies, a voltage is applied by the electric field source 410. The electric field source 410 is shown having a positive forming electrode 412, a negative forming electrode 414, and a ground 416 electrically connected to the capacitor 402. Paraffin 400 is electrically saturated by solidification under electrical stress at a sufficiently high potential. Some waxes may be electrets by low electric fields of about 10 V / cm and high electric fields of about 15 kV / cm. A high potential direct current voltage of about 500-10000 V may be sufficient to permanently retain charge in the wax, and another suitable voltage is about 1800 V corresponding to an electric field of about 11 kV / cm. Depending on the suitable embodiment, an AC or DC current may generate an electric field. The electric field may depend in part on the time required to solidify the wax. Appropriate results are obtained when the electric field is removed while paraffin 400 is completely solidified but kept at elevated temperature. According to another suitable embodiment, the charge is applied to paraffin 400 for about 1 hour.

The electrodes 412 and 414 can be any conventional electrode such as tin, brass or copper disks having a diameter of about 2-5 cm. In addition, electrodes 412 and 414 may be wrapped with foil 404 to inhibit contamination by paraffin 400, which facilitates removal of paraffin after coagulation. After removing the electric field, the underlying layer of foil 404 may remain on the resulting electret paraffin 400. The top layer of foil 404 can be removed and replaced with a loose foil (not shown) arranged to shorten the electret. A cross-sectional view of the resulting electret paraffin 400 is shown in FIG. 11. The wax may also be an electret by other methods known to those skilled in the art.

Without wishing to be bound by any particular theory, when an electric field is applied to paraffin, the axes of the molecules or clusters of molecules are oriented in the direction of the electric field, so that the molecules maintain their orientation as the paraffin solidifies. This molecular orientation allows paraffins to maintain permanent electrical polarization (i.e. upon cooling, molecular dipoles in paraffins are fixed in an orientation determined by the applied electric field).

The resulting electret is at least 5 × 10 ⁻¹¹ C / cm ² , suitably about 1 × 10 ⁻¹⁰ C / cm ² to 2 × 10 ⁻⁹ C / cm ² , and possibly about 30 kV / cm to 1.7 nC polarization charges present in amounts as high as / cm ² . It is not judged that the charge of the obtained electret wax disappears over a long period of time. For example, US Pat. No. 2,284,038 anticipates that electret wax will remain for at least several years. For further information regarding the preparation of electret wax, see US Pat. No. 2,986,524, which describes the preparation of electret wax, the disclosure of which is incorporated herein by reference.

ii. Suitable wax

As used herein, a "wax" is a material that is a plastic solid at room temperature and becomes a liquid of low viscosity when moderately elevated. Soluble wax is in a solid state at about room temperature and usually has a melting point of about 40 to 80 ° C. to avoid melting, burning or softening of the cleaning sheet during manufacture. Examples of such suitable waxes are polyolefins, polyesters, and fluoropolymer waxes having a melting point in this range. Other suitable waxes may have a melting point above 85 ° C., especially when applied to the cleaning sheet after becoming an electret. Electret wax may lose its charge if it melts after the wax becomes an electret (eg, the polarity of the charge may become irregular). According to a suitable embodiment, preference is given to using waxes having a relatively low shrinkage coefficient upon cooling. In order to avoid excessively high hardness of the cleaning sheet, it is sometimes beneficial to use waxes of somewhat lower melting point in the range of about 45 to 70 ° C. This may also be achieved by selecting a wax having a relatively low penetration hardness value (measured by ASTM D 1321).

Since the wax is relatively plastic, it may be deformed or flexible under pressure upon application of relatively weak heat. Suitable waxes, such as paraffin, can be applied to be relatively flexible and to follow the outline of the cleaning sheet. In addition, waxes with large hardness, such as carnauba wax, are acceptable. Too hard wax may shear or remove from the cleaning sheet upon cleaning. The removal of wax from this sheet has the disadvantage that the wax can be transferred from the sheet to the surface to be cleaned. In addition, the use of higher hardness wax may result in a harder cleaning sheet. Of course, the stiffness of the sheet can be a function of several parameters, including the material used to form the particle retention layer, the type of such layer, the type of wax used, the amount and location of the wax present in the layer. In general, suitable waxes have a penetration hardness of at least about 0.2 mm at 25 ° C., preferably from about 0.5 to 3 mm at 25 ° C. as measured according to ASTM D 1321, the disclosure of which is incorporated herein by reference.

The color of the wax in the solid state is preferably white or transparent and does not readily degrade or discolor. Suitable colorless waxes include hydrogenated waxes such as paraffin, tristearin wax, and other hydrogenated vegetable waxes. Other suitable waxes that can be yellowish orange are colored waxes such as beeswax and carnauba wax. According to a suitable embodiment, the natural wax may be treated with preservatives to inhibit degradation or contamination by bacteria and / or pests.

Suitable waxes should hold the electret for a relatively long time. Electret neutralization parameters such as ionization of the ambient air, humidity and moisture can slightly affect these electret waxes. Perhaps changes in temperature, humidity and altitude in the atmosphere will not have much effect on electret wax. This neutralization variable can be minimized by restoring the effective charge on the electret by allowing it to disappear within a relatively short period of time (eg several hours). In addition, these neutralization parameters are minimized by the removal of thin water or foil layers (e.g. short circuits) that cover the surface of the electret until removed, or by packaging with a dry material such as CaCl ₂ by other methods known to those skilled in the art. May be

Suitable waxes may have a permanent electric moment after being charged by the forming electrode. Waxes in this category include insect and animal waxes, such as beeswax, which are secreted by bees. Beeswax has a melting point of 64 ° C., a hardness (penetration) of 2.0 mm at 25 ° C. and 7.6 mm at 43.3 ° C. Suitable waxes also include vegetable waxes, resins, and rosin. Vegetable waxes include candelilla, orycury, japanese wax, orycury wax, douglas-per bark wax, rice bran wax, jojoba, castor wax, laurel wax and carnauba wax. Carnauba wax is in the solid state at room temperature to about 75 ° C. and in the liquid state at temperatures above 83 ° C.

Suitable waxes also include inorganic waxes. Inorganic waxes include montan wax, peat wax, wax, ceresin wax and petroleum wax. Petroleum waxes include semicrystalline, microcrystalline, and paraffin waxes. Generally the microcrystalline wax has a melting point of 60-93 ° C., a viscosity of 10-25 mm ² at 98.9 ° C., and 30-75 carbon atoms per molecule. The paraffin wax consists mainly of alkanes and typically has a melting point of about 40-70 ° C., a viscosity of 4.2-7.4 mm ² at 98.9 ° C. and 20-36 carbon atoms per molecule.

Suitable waxes also include synthetic waxes and asphalt. Synthetic waxes include synthetic waxes such as polyethylene wax, Fischer-Trops wax, chemically modified hydrocarbon waxes, substituted amide waxes, synthetic beeswax and synthetic waxes, oxidized polyethylene waxes, hydrogenated jojoba oils, and alkyl methyl siloxanes (silicone compounds) And silicone waxes).

Other suitable waxes are polyethylene waxes. Polyethylene waxes include low molecular weight (about 10,000 or less) polyethylene having wax-like properties, typically used with petroleum waxes. Polyethylene waxes include olefin polymers having ethylene-like properties, ethylene homopolymers, taylor, propylene, butadiene and copolymers of acrylic acid. One polyethylene wax includes Polywax ™ polyethylene synthetic hydrocarbon wax (from Petrolite Corporation, St. Louis, Missouri, USA) with a melting point of 86 ° C., a hardness of 0.7 mm at 25 ° C. and 6.1 mm at 60 ° C. (measured according to ASTM D 1321). Commercially available). According to a variant, the wax may be a polymer such as polyurethane, polyethylene and / or fluorocarbons. Such polymers can be electrets without raising the temperature above the melting point.

The wax may be relatively pure or used with other waxes and materials. For example, suitable electrets can be prepared using the same weight of resin and carnauba, 40% rosin and 60% carnauba, or wax with 45% resin, 45% carnauba, 10% beeswax, and the like. . Other suitable electrets can be made using some carnauba wax, some rosin, and some beeswax. Such ratios may vary over a wide range.

According to a variant, the wax is ethyl cellulose (a white granular solid in which the hydroxy group of cellulose is substituted with an ethoxy group (OEt)), methacrylate resin (ie, methacryl polymerized by the action of heat, light or benzyl peroxide). Other components such as solid esters of acids), and / or titanium compounds (eg, titanium dioxide and barium titanate) in small portions. If a titanium compound is included, the particle size of components such as carnauba wax may decrease during the cooling period and the charge on the electret surface may obviously increase.

iii. Textiles and other electrets

Fibers (eg, woven and nonwoven) and foams can be directly electrets without using, for example, electret wax. Fiber electrets can be made in the form of sheets or films in which one surface is positively charged and the other surface is negatively charged. For further information on making fiber electrets, see Bernard Gross, "Electret Device for Pollution Control", State of the Art Review, Vol. 6, Optosonic Press 1972 (describe characteristics of electret materials). , U.S. Patent No. 5,057,710 to Nishiura et al. (Explains how to make electret materials), and U.S. Patent No. 5,429,848 to Ando et al. And US Pat. No. 4,486,365, which describes electret filaments, textile fibers, and similar products, the disclosures of which are incorporated herein by reference.

According to a suitable embodiment, the dielectric material may be electret by the ferroelectric effect in which the ferroelectric material exhibits opposite polarity charges at both surfaces due to the applied pressure. According to another suitable embodiment, the dielectric material can be electret by using light (lighting 6000 lux of light) instead of charge at room temperature. In addition, according to another suitable embodiment, certain piezoelectric insulation or semiconductor materials may be electrets under the combined action of illumination and strong electric fields. In addition, according to another suitable embodiment, the dielectric material may be electret by the triboelectric effect.

b. Material of Particle Retention Layer

Typically, the fibers used in the core are made of thermoplastics. It is believed that the thermoplastic material can be formed in the form of a roll that maintains an electrostatic charge over a long period of time, has relatively good insulation, and enables a continuous charging technique. The fibers also include semisynthetic fibers (such as acetate fibers), regenerated fibers (cupra and rayon), natural fibers (cotton and cotton blends), and other fibers or combinations of natural or synthetic fibers. The outer side of the fiber may be coated with electret wax.

In addition, the base layer (ie, core) may be made of a porous sponge or foam as shown in FIG. 2. Suitable foams include polyurethane foams and latex foams. Typically, such foams are prepared using a blowing agent that reacts with a chemical to generate a gas (eg, carbon dioxide) that is trapped in the form of bubbles during polymerization to form the foam. Other suitable foams are phenolic resin foams. Typically, phenol resin foams are prepared by reacting phenol with formaldehyde in the presence of a basic catalyst such as sodium hydroxide or potassium hydroxide, neutralizing the resulting solution and distilling off water. This reaction is believed to produce resol (A-staged resin) containing reactive methol groups. The A-stage resin can be cured by further reacting in the presence of an acid catalyst and a blowing agent to form a phenol resin. During curing, some formaldehyde and water are liberated. The reactive methol groups of the A-stage resin can be further reacted to increase the polymer chain length and / or crosslinking to form a three-dimensional network.

 The base layer (ie, core) may be made of a woven material (eg, a continuous sheet) according to an exemplary embodiment as shown in FIG. 4. The fabric may be a nonwoven fabric, such as a typical fibrous fabric made by weaving (ie interlacing one or more yarns fixed at right angles at the loom), or knitting (ie interlacing one or more yarns). According to a suitable embodiment as shown in FIG. 4, the fabric may be a nonwoven. Nonwovens can be made by mechanically (hydraulic entanglement, etc.), chemically or thermally interlocking layers or networks of fibers or filaments or yarns. Joining fibers or filaments can produce a nonwoven fabric simultaneously with extrusion or by drilling a relatively thin membrane.

The material of the core can be electret by any known method. For example, the core material may be electret by coating with an electret material such as wax. The core material may also be an electret by spinning the fibers in a strong electrostatic field. The core material may also be an electret using the triboelectric effect (ie, rubbing the fibers into other media to induce charge). According to a suitable embodiment, at least 20% of the core material is an electret, and in some cases 50-100% of the core material may be an electret. The core material preferably has a charge of about 1.0 × 10 ⁻¹¹ to 1.0 × 10 ⁻³ C / cm ² , more preferably 1.0 × 10 ⁻⁵ to 1.0 × 10 ⁻³ C / cm ² . The core material has the ability to retain debris having a size of at least about 20 g / m ² . The charge of the core or other material of the cleaning sheet may partially affect the density of the collected particles. The core may comprise non- electret natural or synthetic fibers to increase the fracture strength and elongation of the core. Such non- electret fibers include wool, cotton, cellulose, polypropylene, polyethylene, polyester, polytetrafluorine (PTE), nylon, rayon, acrylic and combinations thereof.

Applying electret wax to the cleaning sheet

Electret wax may be applied to the cleaning sheet or to any element of the cleaning sheet, such as a core, cover, backing layer, or the like. The wax is particularly suitable for application to a fabric surface, such as nonwoven particle retaining layer 330, as shown in FIG. The wax may be cleaned, such as nonwoven cellulose paper towels, hydroentangled polyesters, or PLEDGE ^R GRAB-IT ^™ sweeper cleaning cloths (commercially available from SCJohnson & Son, Leysin, WI) before and / or after the electrets. It can be applied to the sheet. The wax may also be applied to the foamed particle holding layer of the type shown in FIGS. 2-4 or to the cover sheet shown as cover sheet 20 in FIG. According to another embodiment, the electret wax may be applied to the backing layer of the cleaning sheet (shown as backing layer 20 in FIG. 4). According to another variant, the wax can be applied to the central particle holding layer of the type shown in FIGS. 2 to 5 to attract and collect debris through the holes in the cover layer.

Referring to FIG. 12, a cleaning sheet is shown having a woven (or nonwoven) microfiber layer 422 attached to an electret layer 424. The electret layer 424 may be a woven or nonwoven fibrous material coated with electret wax (or fibers that have been electreted by another method). Both electret layer 424 and microfiber layer 422 are particularly suitable for cleaning dry surfaces. The microfiber layer 422 preferably has a thickness of 1-2 mm and consists of fibers having about 1.0 to about 5 denier. It is advantageous to use a microfiber layer formed using a mixture of relatively thick microfibers having 1-3 deniers and finger fibers having deniers of about 0.9 or less, generally about 0.2 or more (preferably about 0.5 to 0.9). can do.

The wax may be applied to the cleaning sheet in various shapes and patterns according to various methods. The molten wax 434 may be applied in the form of discrete spots or islands to the particle retention layer of the cleaning sheet 430 as shown in FIG. 3. The molten wax 434 may also be fluid sprayed (eg, by an air spray gun) to the particle retention layer 432 in the form of discrete droplets or in the form of a uniform spray, sheet or layer as shown in FIG. 13. It may be applied as. According to a suitable embodiment, the wax can be combined with a solvent and sprayed into the particle retention layer to reduce the viscosity of the wax. The solvent may then evaporate while leaving molten or solidified wax on the particle retaining layer. Suitable solvents for paraffin wax include toluene, benzene, other hydrocarbon solvents, chloroform, ethers and mixtures thereof.

According to a variant, molten wax 434 may be applied in a wave shape 436 as shown in FIG. 4. The wax covers the outside of the fiber and may be impregnated, saturated or wetted in whole or in part into the material 432. The wax may be collected between the intersections of the fibers, and / or may bind the fibers together. According to another modification, the molten wax 434 may be deposited in the depression 134 of the particle holding layer 130 as shown in FIG. 15. According to another variant, the molten wax may be applied in one continuous layer on any side or surface of the particle retaining layer. According to a suitable ring embodiment, from about 0.1 to 10% by weight of the wax, preferably from 0.5 to 5% by weight, more preferably from about 0.7 to 2% by weight, based on the dry weight of the particle retention material to which the wax is applied, It may be applied to the particle holding layer. The weight of the wax is partly proportional to the area that can be coated as wax. According to a suitable embodiment, the wax covers at least about 10%, preferably about 30-50% of the surface area of the particle retention layer. It may be beneficial to keep a substantial portion (eg, at least 50%) of the particle retention layer untreated with wax. The amount of wax applied should be such that the material to which the wax is applied has a particle retention capacity of at least about 20 g / m ² .

Outer or cover layer

The cleaning sheet of the present invention may include a cover which covers a part or the whole of the particle holding layer. Referring to FIG. 2, there is shown a core 30 that is covered or enclosed with a cover layer 20 that is substantially free of contact with the working surface or the surface to be cleaned. Cover layer 20 is substantially planar and generally planar. According to the exemplary embodiment shown in FIG. 4, the core 30 may be located in the form of a sandwich between the top cover layer 322 and the bottom or backing layer 320. Cover layer 322 is a generally smooth, flexible planar sheet for cleaning delicate surfaces (eg, wood, glass, plastics, etc.) or hard surfaces. According to another suitable embodiment, a space or other intermediate layer may be located between the core and the cover layer (s).                 

The backing layer may be harder and / or have a larger basis weight than the core or cover layer to provide a support structure for the cleaning sheet. According to another suitable embodiment, a space or other intermediate layer (s) may be located between the backing layer and the outer fabric layer. The backing layer has the desired degree of flexibility and can support the sheet as a whole so that various materials are suitable for use as the backing layer. Examples of suitable materials for use as the backing layer are lightweight (eg, basis weights of about 10 to 75 g / m ² ) flexible materials that can provide the sheet with strength sufficient to withstand tearing or stretching in use. Typically, the backing layer may be relatively thin (eg, having a thickness of about 0.05 mm to about 0.5 mm) and relatively porous. Examples of suitable materials are spunbond or thermal bond nonwoven sheets formed using synthetic and / or natural polymers. Other backing materials that can be used to make the cleaning sheet include relatively porous flexible layers formed using polyesters, polyamides, polyolefins or mixtures thereof. In addition, the backing layer may be made of hydraulically entangled nonwoven fibers when the performance criteria required for a particular application are satisfied. One particular example of a suitable backing layer is a spunbond polypropylene sheet having a basis weight of about 20 to 50 g / m ² .

As shown in FIG. 5, a hole (shown as the hole 22) may be integrally formed in the cover layer 322, which may be a continuous sheet. The hole may be circular as shown in FIG. 7, but may be other shapes, such as a square, star, ellipse, irregular shape, or a combination thereof, depending on the variation. In FIG. 8, the hole 122 is shown as having an irregular shape as another example of the hole 22. According to a suitable embodiment, the perforation of the cover sheet can form a hole. In general, the apertures 22 are large enough to allow sufficient size of debris (eg, 0.5-100 mm) to pass through the particle retention layer. After passing through the pores, the debris flows in the voids (ie the cavity) of the particle holding layer. Each hole 22 has a larger primary diameter (D _1), and a second diameter (D _2), the maximum cross-sectional axis perpendicular to the primary diameter D ₁ of the hole than the outer diameter (see Fig. 8). According to a suitable embodiment, the average primary diameter of all the holes is about 1 to 10 mm, preferably about 2 to 5 mm.

Each hole 22 has a cross-sectional area. The average cross-sectional area corresponds to half of the sum of D ₁ + D ₂ of the holes (ie average cross-sectional dimension = (D ₁ + D ₂ ) / 2). Typically, the average cross-sectional area of each hole is at least about 1 mm ² , more typically from about 1 to 100 mm ² , most typically from about 5 to about 25 mm ² . According to a suitable embodiment, the cross-sectional area of all the holes relative to the surface area of the outer surface of the cover layer is typically about 30% to 95%, more suitably 70% to 90%. The number and average cross-sectional area of the holes are selected such that as the maximum amount of debris passes through the holes, the core is separated from the surface to be cleaned and the debris remains in the core.

The cover layer may be made of a material having a low debris holding force (ie, not attracting or collecting debris significantly) and having a debris holding force lower than the core. According to a suitable embodiment, the cover layer may be made of a thermoplastic material. Thermoplastic materials or fibers include polyamides and polyolefins, polypropylenes, polyethylenes, polystyrenes, polycarbonates, nylons, rayons, acrylics, and the like, and combinations thereof. The thermoplastic material can be prepared according to the melt brown process. Other materials that do not significantly attract debris include woven or nonwoven fibrous fabrics with relatively tightly packed fibers of relatively high degree of entanglement. In addition, other materials include non-fibrous materials, such as perforated polymeric fibers or sheets. According to a suitable embodiment, the core layer may be spunbond or thermal bond polypropylene. According to another suitable embodiment, the cover layer is made of natural materials (eg rubber, latex, etc.), polyolefins (eg polypropylene and polybutene), polyesters (eg polyethylene, polyurethane terephthalate and polybutene terephthalate) , Synthetic materials such as polyamides (eg nylon 6 and nylon 66), acrylonitrile, vinyl polymers and vinylidene polymers (eg polyvinyl chloride and polyvinylidene chloride), and modified polymers, or alloys thereof, or Mixtures, and other materials with relatively high dust holding capacity.

Connection of Cover Layer and Particle Retention Layer

The cover layer may be attached to the core by fasteners, such as melt bonding, as shown by needlepoint 126 in FIG. 3. The fastener functions as a tool for physically and / or chemically bonding or securing the cover layer to the core. According to a suitable embodiment, an adhesive may be used to attach the cover layer to the core. The adhesive should be of a type that is relatively soft and nonabrasive to the surface to be cleaned. The adhesive should also be one that can pass debris through the holes in the cover layer and does not substantially retain debris. The adhesive may be applied in a solid layer, in a continuous pattern (eg, a circle or sigmoidal pattern), in a discontinuous pattern (eg, a series of lines of dots), or in any other desired pattern such as a western board, cross, and the like. The adhesive may be applied to the cover layer, core, or any other suitable intermediate surface or backing layer. According to a suitable embodiment, all or part of the cover layer and the core may be bonded together (eg, melt bonding at a localized location, ultrasound, infrared, spot welding, etc.). According to another suitable embodiment, the cover layer may be attached to the core by entanglement (eg, hydraulic weaving) or other fasteners (eg, constituent adhesive, clips, embossing, etc.).

Dimensions of the cleaning sheet

In general, the physical dimensions of the cover layer and core are not considered important. Typically, the outer periphery of the cover layer 20 is larger than the outer periphery of the core 30 as shown in the figure, so that the debris 68 is retained in the core 30 before the holes 22 in the cover layer 20. Can pass through As shown in Figure 2, the cover layer 20 has a generally small thickness (T ₁₎ greater than the thickness (T ₂₎ of the core (30). As a non-limiting example, the cover layer may have an average thickness of about 1 mm or less, preferably 0.05 to 0.5 mm. The core may have an average thickness of about 5 mm or less, preferably 1 to 2 mm. According to a suitable embodiment as shown in FIG. 1, the cover layer 20 has a shape similar to the core layer 30. The cleaning sheet can be about 8 inches long and about 12 inches wide.

Cleaning tools and how to use

The pad 10 may be used alone (eg in the form of a rag) or in combination with other tools to clean the surface 66. In general, the pad 10 is flexible to accommodate any appearance of the surface 66 to be cleaned (eg, flat, jagged, irregular, etc.). Thus, the pad 10 is particularly suitable for cleaning hard and hard surfaces. According to another embodiment, the pad 10 may be semi-rigid so that it is particularly suitable for cleaning flat surfaces. The pad 10 may also be used to clean relatively soft surfaces such as rugs, carpets, upholstery materials and other soft products.

Referring to FIG. 1, a pad 10 is shown attached to a cleaning head 62 of a cleaning tool (shown as dust mop 60) in accordance with an exemplary embodiment. The head 62 has a carriage 80 that provides a fastener (shown as a spring clip 82) for mounting the pad 10. In the mounting structure 84, an elongate hard member (shown by the split handle 64) is attached to the carriage 80. Mounting structure 84 has a yoke (shown by arm 86) having a y-shaped end 88 rotatably mounted to a socket (shown as ball joint 90). The arm 86 is threadedly attached to the handle 64 by an adapter (shown as connector 92). According to a suitable embodiment, the cleaning tool may be a broom, a brush, a polisher, a handle or the like suitable for fixing the cleaning sheet. The cleaning sheet may be attached to the cleaning tool by any of a variety of fasteners (eg, friction clips, screws, adhesives, retaining fingers, etc.). According to another suitable embodiment, the cleaning sheet may be attached in the form of a single unit or in the form of a plurality of sheets.

The components of the cleaning tool, ie the wax of the mounting structure, the adapter, the handle and the electret, can be provided individually or in combination (eg a kit or package). The components of the cleaning tool can be assembled quickly and easily in the field (eg, workshop, home, office, etc.). The cleaning tool may also be provided in a preassembled state and / or in a single state. According to a suitable embodiment, the cleaning sheet is shaped for use with a PLEDGE ^R GRAB-IT ^™ sweeper (commercially available from SCJohnson & Son of Leysin, Wisconsin, USA).

To clean the surface 66, the pad 10 may be secured with a clip 82 to the head 62 of the bag 60. The pad 10 comes into contact with the surface 66 and moves along the surface 66 (eg, horizontal direction, vertical direction, rotational movement, linear movement, etc.). Debris 68 from surface 66 is provided or attracted through cover 22 into cover layer 20. The electrostatic charge of the electret material in the core 30 can attract debris into the core 30 through the holes 22 of the cover layer 20 as shown in FIG. 2. The voids (shown as cavity 34) of the core 30 collect and / or capture debris 68 into the cavity 32 of the pad 10. The outer surface of the cover layer 20 remains substantially free of debris. After use, pad 10 may be removed from mop 60 for processing or cleaning (eg, washing, shaking, debris, etc.). According to another suitable embodiment, the cleaning sheet can be used alone (eg by hand) to clean the surface. According to the embodiment as shown in FIG. 1, electret wax may be applied to pad 10 at room temperature.

Test Methods

c. Fracture Strength (cross machine direction)

From each cleaning sheet, a specimen having a width of 30 mm can be cut in a direction perpendicular to the fiber orientation in the sheet (ie cross machine direction). The specimen may be fixed at a distance between chucks of 100 mm in a tensile tester and drawn at a rate of 300 mm / min in a direction perpendicular to the fiber orientation. The load value (the first peak value of the continuous curve obtained by the stress / strain measurement) at which the sheet begins to break can be taken as the breaking strength.

d. Elongation at load of 500 g / 30 mm

The elongation of the specimen can be measured at a load of 500 g in the measurement of the breaking strength in the cross machine direction described above. For this test, "elongation" is defined as the percent increase in relative length of a 30 mm strip of cleaning sheet material when a tensile load of 500 g is applied to the strip.

c. Tangle factor

Scrim can be removed from the nonwoven fiber assembly. If the scrim has a lattice net structure, typically this is accomplished by cutting the fibers making up the network sheet at their junction and carefully removing the network sheet from the nonwoven fiber assembly using tweezers. Specimens having a width of 15 mm can be cut in a direction perpendicular to the fiber orientation in the sheet (ie cross machine direction). The specimen may be fixed at a distance between chucks of 50 mm in a tensile tester and drawn at a rate of 30 mm / min in the direction perpendicular to the fiber orientation (cross machine direction). The tensile load value F (g) with respect to the elongation of the specimen can be measured. The value obtained by dividing the tensile load value F by the width m of the specimen and the basis weight W (g / cm ² ) of the nonwoven fiber assembly is taken as the stress S (m). Plot stress (S) against elongation (“strain” (%)) to obtain a stress-strain curve (ie, stress S (m) = (F / 0.015) / W).

In the case of nonwoven fiber agglomerates that are held in concert only through entanglement of the fibers, a linear correlation is generally obtained at the initial stage of the stress-strain (elongation) curve. The slope of the straight line is calculated by the entanglement coefficient m. For example, in the exemplary stress-strain curve shown in FIG. 9 (the vertical axis represents stress and the horizontal axis represents strain and O represents the origin), the limit of linear correlation is represented by P and the stress at P Is represented by S _p , and the modification at _P is represented by γ _p . In this case, the entanglement coefficient is E = S _p / γ _p . For example, when S _p = 60 m and γ _p = 86%, E = 60.0 / 0.86 = 70 m. The line OP is not always completely straight. In this case, the straight line is close to the line OP.

Although only a few exemplary embodiments have been described, the invention is not limited to one particular embodiment. Indeed, in order to practice the present invention, those skilled in the art will appreciate that variations on the embodiments described herein (e.g., the size, structure, shape and ratios of various elements, parameter values, mounting arrangements, Or change in materials used). Various changes may be made to the disclosure herein without departing from the spirit of the invention.

The cleaning sheet of the present invention can be made using industrially available methods, devices and materials. In addition, the cleaning sheet can be used on various surfaces such as plastic, wood, carpet, fabric, glass, and the like. Also provided are cleaning tools and methods for cleaning surfaces using the cleaning sheets. The cleaning tool may be manufactured in the form of an intact tool or in the form of a cleaning tool kit. Such intact tools include gloves, dusters and rollers. The kit of the invention, which is designed for use for cleaning surfaces, has a cleaning head and a cleaning sheet that can be connected to the cleaning head. The kit can also have a yoke that can be installed on the cleaning head and an elongated handle for attaching to the yoke. When provided in the form of a fully assembled cleaning tool or kit, the cleaning tool may comprise a cleaning head capable of removably attaching the cleaning sheet to the cleaning head.

Claims (28)

A cleaning sheet comprising a particle holding layer for collecting and retaining the particles as a cleaning sheet for cleaning a surface to remove particles from the surface, wherein the particle holding layer comprises electret wax. The cleaning sheet of claim 1, wherein the electret wax has a melting point of 40 ° C. or higher. delete delete delete  The cleaning sheet of claim 1, wherein the electret wax is present on at least 10% of the outer surface. delete The cleaning sheet of claim 1, wherein the particle holding layer has a charge of 1.0 × 10 ⁻¹¹ C / cm ² or more. The cleaning sheet of claim 1, wherein the particle retaining layer comprises a dust retaining material selected from the group consisting of woven fabrics, nonwovens, foams, and combinations thereof. delete delete delete delete delete delete delete delete delete Forming a sheet from the particle retention material comprising at least one of woven fiber, nonwoven fiber or foam; Applying a non- electret wax to at least a portion of the particle retaining material; Applying the electric field to the sheet of particle retaining material to make the wax into an electret. The method of claim 19, Heating the sheet of particle retaining material to a temperature sufficient to soften or melt the wax; Maintaining the wax in a softened state while applying an electric field to the sheet of particle retaining material; And further cooling the sheet of the particle retaining material sufficiently to solidify the wax. delete delete delete delete delete Forming a sheet from the particle retention material comprising at least one of woven fiber, nonwoven fiber or foam; Spraying the molten wax onto at least a portion of the particle retaining material such that molten wax passes through the electric field; Cooling the molten wax to form a solidified electret wax. As a cleaning tool for collecting and maintaining debris, With a cleaning head; A cleaning sheet having a particle retaining layer for collecting and retaining particles suitable for connection to said head, said particle retaining layer comprising electret wax. delete

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