WO2021150823A1

WO2021150823A1 - Nonwoven abrasive scrubber

Info

Publication number: WO2021150823A1
Application number: PCT/US2021/014516
Authority: WO
Inventors: Vinayak OGALE; Veeraraghavan Srinivasan; Manisha MOHAPATRA; Mitul D. Zaveri; Sumi Dinkar
Original assignee: Saint-Gobain Abrasives, Inc.; Saint-Gobain Abrasifs; Unilever Plc
Priority date: 2020-01-23
Filing date: 2021-01-22
Publication date: 2021-07-29

Abstract

Nonwoven abrasive articles and methods of forming nonwoven abrasive articles disclosed achieve improved abrasive performance and comprise a lofty, open web of fibers having a first abrasive composition disposed on the web of fibers. The lofty, open web of fibers includes a specific combination of physical and performance properties that allow the abrasive articles to achieve abrasive performance comparable or exceeding conventional nonwoven abrasive articles.

Description

NONWOVEN ABRASIVE SCRUBBER

TECHNICAL FIELD

This disclosure relates, in general, to articles and methods regarding nonwoven abrasive articles that achieve improved abrasive performance. The nonwoven abrasive articles comprise a lofty, open web of a blend of fibers having an abrasive composition disposed on the fibers. The nonwoven abrasive articles possess physical and performance properties that beneficially exceed the state of the art.

BACKGROUND ART

Nonwoven abrasive articles, including hand held nonwoven scrubbing articles, are used in various applications to condition and clean the surface of a workpiece to a desired condition. Various types of nonwoven abrasive articles are used for cleaning a variety of workpieces, such as cooking and eating utensils and the like by abrasively removing food particles, sticky oily residues, and associated unhygienic contaminants to restore the workpieces to good and acceptable conditions before every use.

Nonwoven abrasive articles, such as handheld nonwoven scrubbers and pads have been made from a variety of materials, however such scrubbers suffer various disadvantages, such as disintegrating relatively quickly, are difficult to keep clean, can scratch work piece surfaces, are not able to quickly remove stubborn food deposits, and are unpleasant to the touch.

Further, workpieces surfaces can have complex shapes that conventional nonwoven abrasives do not have the right balance of physical properties and abrasive performance to provide a satisfactory finish or cleaning. Therefore, there continues to be a need for improved abrasive products, including improved nonwoven abrasive products.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure may be better understood, and its numerous features and advantages made apparent to those skilled in the art by referencing the accompanying drawings.

FIG. 1 is an illustration of a nonwoven abrasive article according to an embodiment.

FIG. 2 is an illustration of portion 108 of FIG. 1 showing the structure of the nonwoven abrasive article in greater detail according to an embodiment.

FIG. 3 is an image of hand held nonwoven abrasive articles having a diamond shape, a quadrilateral shape, and a pentagonal shape according to an embodiment. FIG. 4 is a process flow diagram for a method of preparing a nonwoven abrasive article according to an embodiment.

FIG. 5 is a graph showing the comparative performance of sample nonwoven abrasive articles according to embodiments compared to a conventional abrasive article.

FIG. 6 is a graph showing the comparative longevity of sample nonwoven abrasive articles according to embodiments compared to a conventional abrasive article.

The use of the same reference symbols in different drawings indicates similar or identical items.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

An embodiment of a nonwoven abrasive article 100 is illustrated in FIG. 1. The nonwoven abrasive article 100 comprises a substrate comprising an open web 102 of lofty nonwoven fibers 104 and a first abrasive composition disposed on the fibers, wherein the first abrasive composition comprises a first plurality of abrasive particles 106 dispersed in a first polymeric composition. The nonwoven abrasive article 100 can comprise a combination of beneficial physical and abrasive properties. In certain embodiments, the nonwoven abrasive article can comprise a particular combination of bending stiffness, a loft, an elongation %, a tensile strength, a Toughness, a mean pore size, an air permeability, a Machine Direction Orientation Index, and a Burnt Food Removal Rating. A portion 108 of the nonwoven abrasive article is illustrated in greater detail by FIG. 2 according to an embodiment. FIG. 3 includes images of nonwoven abrasive articles according to another embodiment.

FIG. 2 is an illustration showing the structure of an open web 202 of lofty nonwoven fibers 204 comprising a first abrasive composition disposed on the fibers 204, wherein the first abrasive composition comprises a first plurality of abrasive particles 206 dispersed in a first polymeric composition 210.

FIG. 3 is an image of nonwoven abrasive articles that have been formed according to embodiments to have beneficial shapes (diamond shape, rectangular shape, pentagonal shape) that fit comfortably in a person’s hand.

FIG. 4 is a process flow diagram of a method 400 of making a nonwoven abrasive article according to an embodiment. In step 402, forming a nonwoven substrate (fiber web) occurs. In certain embodiments, forming of the nonwoven substrate is accomplished by air laid formation of the fiber web. Alternate web forming methods can be used. In step 403, the nonwoven substrate is subjected to a mechanical fiber entanglement process, such as single needle punching or double needle punching (also called herein “single needling” and “double needling”, respectively). In step 404, mixing together of abrasive particles and a first polymeric composition occurs to form an abrasive composition, which can be applied to the fibers of the non-woven substrate using coating and curing techniques. Optionally, in step 410, forming of the nonwoven abrasive article into a particular shape occurs. Forming can be accomplished by converting (i.e., cutting) of the nonwoven abrasive article into any desired shape.

The nonwoven abrasive article can comprise a combination of certain physical and abrasive properties. Unless otherwise stated, all values can be average values calculated from a statistically relevant sample size.

The nonwoven abrasive article can comprise a particular bending stiffness. In an embodiment, the bending stiffness can be at least 100,000 milligrams (mg) to not greater than 120,000 mg. In another embodiment, the bending stiffness can be not greater than 115,000 mg, such as within a range of at least be at least 105,000 milligrams (mg) to not greater than 115,000 mg. In a particular embodiment, the bending stiffness can be not less than 108,000 mg to not greater than 112,000 mg. Bending stiffness can be measured using a Gurley type bending resistance machine according to ASTM D6125 - 97, Standard Test Method for Bending Resistance of Paper and Paperboard (Gurley Type Tester), as measured in the machine direction.

The nonwoven abrasive article can comprise a particular loft (i.e., thickness). In an embodiment, the loft can be not less than 14 mm and not greater 16 mm, such as at least 14 mm and not greater than 15 mm.

The nonwoven article 100 may comprise a particular elongation percentage in the machine direction (i.e., percentage of elongation before breakage and/or separation of fibers 104). In an embodiment, the nonwoven article 100 may comprise an elongation percentage of at least at least 20% and not greater than 30%, such as at least 23% and not greater than 27%. Elongation can be measured according to ASTM D5034 - 09(2017), Standard Test Method for Breaking Strength and Elongation of Textile Fabrics (Grab Test), as measured in the machine direction.

The nonwoven abrasive article 100 may comprise a particular tensile strength in the machine direction. In some embodiments, the nonwoven abrasive article 100 may comprise a tensile strength of at least 30 kilograms force (kgf) and not greater than 55 kgf, such as within a range of at least 38 kgf and not greater than 45 kgf, or even at least 40 kgf to not greater than 50 kgf. Tensile strength can be measured according to ASTM D5034 - 09(2017), Standard Test Method for Breaking Strength and Elongation of Textile Fabrics (Grab Test), as measured in the machine direction.

The nonwoven article 100 may comprise a particular Toughness (or Work of Rupture), which is a measure or calculation of the area under the curve of a plot of stress vs strain, based on values measured during tensile strength testing. In some embodiments, the nonwoven article 100 may comprise a Toughness of at least 6.5 J to not greater than 9.5 J, such as within a range of at least 7.0 J to not greater than 9.0 J.

In an embodiment, the nonwoven abrasive article can comprise a particular density.

In an embodiment, the density can be not less than 85 kg/m to not greater than 115 kg/m , such as at least 90 kg/m to not greater than 110 kg/m .

The nonwoven article 100 can comprise a particular pore size (i.e., mean pore size). The pore size can be measured according to ASTM D6767 - 16, Standard Test Method for Pore Size Characteristics of Geotextiles by Capillary Flow Test. In some embodiments, the nonwoven article 100 may comprise a mean pore size of at least 114 micrometers (pm) to not greater than 134 micrometer, such as within a range of at least 116 micrometer to not greater than 132 micrometers.

The nonwoven abrasive article 100 can comprise a particular air permeability. The air permeability can be measured according to ASTM D737, Standard Test Method for Air Permeability of Textile Fabrics. In some embodiments, the nonwoven abrasive article 100 may comprise a permeability of at least 12 ft /min/ft to not greater than 15 ft /min/ft , such as at least 13 ft /min/ft and not greater than 15 ft /min/ft .

The nonwoven abrasive article can have a particular mass per unit area, such as g/m² (also called “GSM”), commonly known as the “weight” of the nonwoven abrasive article. In an embodiment, the weight can be not less than 1350 GSM and not greater than 1550 GSM, such as not less than 1400 GSM and not greater than 1500 GSM.

The nonwoven abrasive article 100 can comprise a beneficial Machine Direction Orientation Index as measured according to NWSP 407.0.R0(15), “Fiber Orientation Distribution of Nonwoven Fabrics.” In one embodiment, the nonwoven abrasive article 100 may comprise a Machine Direction Orientation Index of at least 1.18 and not greater than 1.22, such as at least 1.19 and not greater than 1.21.

In an embodiment, the nonwoven abrasive article 100 may comprise a performance rating, such as with respect to a specific amount of burnt food composition as described herein (Burnt Food Removal Rating) within a specific amount of time according to the method and procedure according to Example 2. The removal rate can also be beneficial with respect to an amount of time the removal rate is sustainable, such as for a number of continuous uses and or for a period of useful life. In an embodiment, the removal rate can be expressed as Burnt Food Removal Rating of less than 36 seconds to completely remove 25 g of a homogeneous mixture of charred wheat flour, whole grain flour, rice atta, and sunflower oil from a stainless steel plate as described herein according to the method and procedure of Example 2. In some embodiments, the nonwoven article 100 may comprise a Burnt Food Removal Rating of not less than 36 seconds for 7 consecutive days (tested once per day). Further, it will be appreciated that the nonwoven abrasive article 100 may comprise a Burnt Food Removal Rating within a range of at least 25 seconds and not greater than 36 seconds for 7 consecutive days.

In an embodiment, the nonwoven substrate comprises a three-dimensional nonwoven open web formed of lofty fibers that have been entangled and bound together. The fibers can be bound together by one or more binder coating compositions (also called herein a “web binder” composition) that can be applied and cured prior to the application of any abrasive compositions as described later herein.

In an embodiment, the fibers of the web may alternatively be, and/or further, bound and entangled by subjecting the web to a mechanical fiber entangling process, such as a needle punching process, commonly known as “needling”. Needle punching may be accomplished by single-needling (uses a single needling board) or double-needling (uses two needling boards).

The fibers of the nonwoven substrate can be an organic material, an inorganic material, a natural material, a semisynthetic material, a synthetic material, or a combination thereof, such as polyamide fibers. In one embodiment, the nonwoven substrate is made of poly[imino(l,6-dioxohexamethylene)iminohexamethylene] fibers (“Nylon 6,6” fibers).

The fiber size can be expressed through average denier, a measure of linear density, which is equal to the mass in grams per 9,000 meters of length of a single filament. For instance, a nylon fiber measuring 200 denier means that 9,000 meters of this fiber weighs 200 grams. In one embodiment, the nonwoven substrate may include a blend of fibers, such as 72-80 wt.% of fiber having a linear density of 57-63 denier and 22-28 wt.% of fiber having a linear density of 12-18 denier. In a more particular embodiment, the nonwoven substrate can have a blend of 15 denier and 60 denier fibers. For example, the amount of 60 denier fibers can be approximately 75 wt.% and the amount of 15 denier fibers can be approximately 25 wt.%. Abrasive Particles

The abrasive particles can be alumina, and may include #240-280 grit size particles of alumina (i.e., abrasive particles having a mean particle size of approximately 28-56 microns, with a median particle size of 37 microns).

Polymeric Compositions

A first polymeric composition can be formed of a single polymer or a blend of polymers. In a specific embodiment, the first polymeric composition can comprise a phenol formaldehyde polymer.

A second polymeric composition can be the same as or different from the first polymeric composition.

First Abrasive Composition

A first abrasive composition can have a certain overall composition of components.

In an embodiment, a first abrasive composition can comprise: 25 to 55 wt.% abrasive particles; 43 to 73 wt.% phenol formaldehyde polymer; and 0 to 2 wt.% total additives. Second Abrasive Composition

A second abrasive composition can have a beneficial overall composition of components. The second abrasive composition can be the same as or different than the first abrasive composition. In an embodiment, a second abrasive composition can comprise:

55 to 85 wt.% abrasive particles; 15 to 45 wt.% phenol formaldehyde polymer; and 0 to 30 wt.% total additives.

Example 1. Nonwoven Abrasive Sample Preparation

Nonwoven substrates (i.e., lofty, open webs of fibers) were formed. The nonwoven substrates comprised air-laid webs (Rando-Webber machine) of virgin polyamide (Nylon 6,6) staple fibers (staple fiber length of 30 mm to 70 mm). Each web had a weight of 250-300 g/m (“GSM”) and was comprised of 75 wt.% 60 denier fibers and 25 wt.% 15 denier fibers. The web fibers were bound together with an acrylic latex web binder composition.

Each of the nonwoven substrates underwent a two-sided, double needling process.

The double needling process was used to produce a sample (S3) and comparative nonwoven substrate (Cl 8). The sample and comparative nonwoven substrates were formed to have different lofts as shown in Table 3.

After the needling process, the nonwoven substrates were coated with abrasive compositions using a “Dip and Spray” process to form nonwoven abrasive articles. Sample (S3) and comparative (Cl 8) nonwoven abrasive articles were produced according to the following coating and curing process. A first polymeric abrasive composition precursor was disposed onto and throughout a nonwoven substrate by dipping the nonwoven substrate into the first polymeric abrasive composition precursor. The first abrasive composition precursor comprised 33-34 wt.% of aluminum oxide #240-280 grit abrasive particles dispersed in a phenolic resin composition as described below in Table 1. Table 1. Dip Coating

Table 2. Spray Coating

The sample and comparative coated webs were then passed through an oven, curing the spray coating and forming a completed nonwoven abrasive article. The sample (S3) and comparative (Cl 8) nonwoven abrasive sheet materials were then tested for certain structural and physical properties, which are described in Table 3. The nonwoven abrasive sheet materials were then converted (i.e., cut) into handheld size nonwoven abrasive scrubbers having various shapes: rectangular shape, a pentagonal shape, and a diamond shape for abrasive performance testing.

Table 3.

Example 2. Burnt Food Performance Testing

Sample hand held nonwoven abrasive scrubbers (S-A and S-B) having a pentagonal shape were produced in the same manner described above for the S3 embodiment and were tested against a conventional state-of-the art hand held nonwoven abrasive scrubber (nylon 6,6, - Scotch-Brite brand). The comparative performance testing consisted of abrasive cleaning of a controlled amount of a burnt on food stain from a stainless steel metal plate (10 inch Dia.). The procedure was as follows: A homogeneous mixture of 3.3g wheat flour +3.3g whole grain flour +3.4g rice atta +5g sunflower oil +10ml water was prepared. Twenty five grams (25g) of the mixture was applied to the center of the stainless steel plate (7-8 inch diameter). The stainless steel plate was placed on a suitable heat source (e.g., hot plate) having a temperature of 200°C and the food mixture was allowed to char for 2 minutes and then cool to room temperature. A soap (e.g., grated soap powder) and water solution (ratio 1:1) was prepared. The charred food plate was rinsed with water. A scrubber (sample or comparative) was rinsed with water and allowed to drip dry. Five milliliters (5ml) of the soap solution were applied to the char and the scrubber was held in the palm of the hand an applied to and the plate. Scrubbing action (six times clockwise & six times counterclockwise) was performed on the char surface and the time recorded. The plate and the scrubber were rinsed in flowing water. The cycle of applying soap solution, scrubbing action, and rinsing was repeated until the char was completely removed. The time to completely remove the char was recorded. The test was repeated once a day for consecutive days until the sample and comparative scrubbers failed (i.e., the nonwoven abrasive article had deteriorated to the point that a hole was worn through the nonwoven abrasive article). The testing results are shown in FIG. 5 and FIG. 6.

All the sample nonwoven abrasive scrubbers (“S-A” and “S-B”) greatly exceeded the abrasive performance of the conventional (“Comparative”) abrasive scrubber. Surprisingly and beneficially, as shown in FIG. 5 and FIG. 6, the sample scrubbers S-A and S-B had a total useful life (“longevity”) of 16 consecutive days, which was 145% of the useful life of the conventional scrubber, which was only 11 days. Further, as shown in FIG.5, both sample scrubbers S-A and S-B were able to maintain the ability to completely remove the burnt food char in under 36 seconds (Burnt Food Removal Rating of less than 36 seconds to remove all char) for a greater number of consecutive days than the conventional scrubber. Sample S-B maintained the Burnt Food Removal Rating of less than 36 seconds for 10 days (145% of the conventional scrubber) and sample S-A maintained the Burnt Food Removal Rating of less than 36 seconds for 11 days (157% of the conventional scrubber). As is shown in FIG. 5, the Burnt Food Removal Rating for both S-A and S-B varied from approximately 42 s to 47 s for days 12 to 16.

Claims

WHAT IS CLAIMED IS:

1. A nonwoven abrasive article comprising: a body including: a nonwoven substrate comprising a lofty, open web of a plurality of fibers, wherein the plurality of fibers comprises 72-80 wt.% of 57-63 denier fibers and 22-28 wt.% of 12-18 denier fibers; and an abrasive coating overlying the nonwoven substrate, wherein the abrasive coating comprises 240-280 grit aluminum oxide abrasive particles dispersed in a polymeric binder, wherein the abrasive coating comprises 76-79 wt.% of a total weight of the body, and wherein the abrasive particles comprise 37-39 wt.% of a total weight of the body; wherein the nonwoven abrasive article comprises: a loft within a range of at least 14 mm to not greater than 16 mm; a Machine Direction Orientation Index of at least 1.18 to not greater than 1.22; a mean pore size of at least 114 microns to not greater than 134 microns; an air permeability of at least 12 ft /min/ft to not greater than 15 ft /min/ft ; a bending stiffness of at least 100,000 milligrams to not greater than 120,000 milligrams; a tensile strength of at least 30 kilograms force (kgf) to not greater than 55 kgf; a Toughness of at least 6.5 J to not greater than 9.5 J; and a Burnt Food Removal Rate of not greater than 36 seconds for at least 7 consecutive days.

2. The nonwoven abrasive article of claim 1, wherein the nonwoven abrasive article comprises a loft of not greater than 15 mm.

3. The nonwoven abrasive article of claim 1, wherein the nonwoven abrasive article comprises an air permeability of at least 13 ft /min/cm and not greater than 15 ft /min/cm .

4. The nonwoven abrasive article of claim 1, wherein the nonwoven abrasive article comprises a bending stiffness of at least 105,000 milligrams to not greater than 115,000 milligrams.

5. The nonwoven abrasive article of claim 1, wherein the nonwoven abrasive article comprises a tensile strength of at least 38 kilograms force (kgf) to not greater than 41 kgf, or at least 40 kgf to not greater than 50 kgf.

6. The nonwoven abrasive article of claim 1, wherein the nonwoven abrasive article comprises a Toughness of at least 7.0 J to not greater than 9.0 J.

7. The nonwoven abrasive article of claim 1, wherein the nonwoven abrasive article comprises a density of at least 85 kg/m to not greater than 115 kg/m .

8. The nonwoven abrasive article of claim 1, wherein the nonwoven abrasive article comprises an elongation of at least 20% to not greater than 30%.

9. The nonwoven abrasive article of claim 1, wherein the nonwoven abrasive article comprises a weight of at least 1350 g/m to not greater than 1550 g/m .

10. The nonwoven abrasive article of claim 1, wherein the fibers comprise polyamide fibers.

11. The nonwoven abrasive article of claim 1, wherein the polymeric binder comprises a phenol formaldehyde polymer.

12. The nonwoven abrasive article of claim 1, wherein the aluminum oxide abrasive particles comprise fused aluminum oxide.

13. The nonwoven abrasive article of claim 1, further comprising 36-38 wt.% abrasive particles for a total weight of the abrasive article, 23-25 wt.% of the plurality of fibers for a total weight of the abrasive article, and 37-39 wt.% polymeric binder for a total weight of the abrasive article.