KR20020043644A - Flexible Abrasive Article Releasing Low Amounts of Contaminants - Google Patents

Abstract

The present invention provides a flexible abrasive article comprising abrasive particles attached to a porous support with at least one binder, wherein the abrasive article has selected extractable cationic particles of less than 300 ppb per m ² and less than 500 × 10 ⁶ releaseable particles. It includes. In addition, the porous support 100 is coated with a make coating to form a coated support; (20) coating the coated support 100 with abrasive particles to form a particle coated support; (22) curing the particle coated support; Coating the cured particle coated support with a size coating to form a size-coated support; (28) curing the size-coated support; Converting the cured, size-coated support to form a shaped abrasive article; Post-cleaning the shaped abrasive product to remove unwanted contaminants; A method of making an abrasive article is provided that includes packaging a cleaned and shaped abrasive article.

Description

Flexible Abrasive Article Releasing Low Amounts of Contaminants}

The present invention relates to abrasive articles, in particular abrasive articles which are particularly suitable for use in critical or controlled environments.

Increasing industrial processes need to be isolated from possible physical and chemical contaminants everywhere. Conversely, other industrial processes may need to be sequestered in the general environment because of their toxic or infectious nature. This need is generally met by the construction, assembly and use of so-called "clean rooms" (also known as "clean rooms").

Such equipment has been found to be widely used in the manufacture of semiconductor devices that must minimize the presence of external contaminants such as unwanted particles and ions. For example, processes such as crystal growth, ion implantation, metal deposition, and etching are typically performed in low pressure (vacuum) chambers or reactors operating in clean room environments. After a period of use, these chambers are inevitably contaminated and therefore need cleaning. Depending on the contaminating nature, an abrasive product may be needed to remove sticky contaminants. This polishing operation generates particulate matter that may contaminate the clean room environment. In addition, the abrasive product itself may deliver unwanted particles and / or ionic portions into the chamber and / or the clean room. Thus, there is a need for abrasive products for use in critical clean room environments. Such abrasive products must efficiently remove residues from the reactor surface, minimize the release of particles into the clean room environment, and minimize the transfer of ionic contaminants into the reactor and / or clean room.

Summary of the Invention

One embodiment of the present invention provides a flexible abrasive article comprising a foraminous support, one or more binders, and abrasive particles, wherein the abrasive article contains a minimum amount of releasable physical and chemical contaminants, When used to clean, it provides a clean workpiece with a minimum amount of physical and chemical contaminants and does not damage the workpiece surface.

Other embodiments of the invention

Providing a porous support;

Coating the porous support with a make coating;

Coating the coated support with abrasive grains;

Curing the particulate coated support;

Coating the particulate coated cured substrate with a size coating;

Curing the size-coated support;

Converting the cured, size-coated support to a useful form of abrasive product;

Post-clean the abrasive product to remove possible workpiece contaminants;

Packaging post-cleaned abrasive products

Provided is a method of making a flexible abrasive product, comprising the steps.

"Flexible abrasive product" refers to an abrasive product in which the abrasive coating has a sharp edge like a blade when folded over itself with the abrasive surface exposed.

"Porous support" refers to a porous organic support having pores defined by interconnecting gaps over at least one surface of the support. For example, continuous bubble foam supports or lofty, fibrous nonwoven webs or fabrics are suitable as porous supports.

"Make coat precursor" refers to a coatable resinous adhesive material that is applied to the coatable surface of the pores of the porous support such that the abrasive particles are secured to the porous support.

"Make coat" refers to a cured resin layer on the coatable surface of the pores of a porous support formed by curing the make coat precursor.

"Size coat precursor" refers to a coatable resinous adhesive material applied to the coatable surface of a hole in a porous support over a make coat.

"Size coat" refers to a cured resin layer on the curable surface of the pores of a porous support that is formed by curing a size coat precursor.

By "cured" or "fully cured" is meant cured polymerizable curable and coatable resins.

"Fine abrasive particles" refers to particles with abrasive effects comprising any of the materials described above having a particle size distribution with a very preferred median particle diameter of about 60 microns or less. Spherical particle morphology is assumed to refer to the median particle diameter based on standard test methods that can be used for the measurement of particle diameters, for example ANSI test method B74.18-1884.

"Substantially uniform" means that when the surface is visually observed by microscopic examination, the coatable surface of the contour and the wall, i.e. the coatable surface defined by the gap or gap, is without significant agglomeration of the resin and particles. Refers to the distribution of fine abrasive particles in the final product in which abrasive particles are distributed. In the final product, most of the particles are placed along the coatable surface of the hole in order to have a polishing effect in the initial application of the product.

The abrasive articles of the present invention may be provided in the form of hand pads, endless belts, discs, compacted or compressed wheels, and the like. In addition, the articles of the present invention may be laminated to other articles, such as nonwovens, free bubble foams, continuous bubble foams, or rigid foam supports, or may be provided in the form of rolls with or without perforations therein. .

In the preparation of the product, the porous support is prepared or otherwise provided. The make coat precursor composition is applied to the surface of the porous support to form the first coating layer. A number of fine abrasive particles are applied to the first coating layer and the make coat precursor composition is at least partially cured. Optionally, the size coat precursor composition is applied over the abrasive particles and the first coating layer to form a second coating layer. The first and second coating layers are cured to attach the abrasive particles to the coatable surface of the pores of the porous support, where the particles are attached to the surface in a substantially uniform distribution along their perimeter.

Using the deposition method described in US Pat. No. 5,863,305, the fine abrasive particles are preferably deposited on one major surface of the porous support first and then on the second major surface of the porous support, thereby depositing the fine abrasive particles on the make coat precursor. Keep calm. It is preferable to apply larger abrasive particles, ie particles of diameter 60 microns or more, to the make coat precursor by known methods such as drip coating or electrostatic coating. Preferably, the make and size coat precursors are thermoset, coatable polyurethane resins. Similarly, when applied to a product, it is desirable to apply any size coat onto a partially cured make coat. Subsequently, the make coat precursor and the size coat precursor are sufficiently cured to provide the flexible abrasive product of the present invention, and the product thus produced may be further processed to provide a hand pad, endless belt, disc, compacted or compacted wheel, and the like. .

1 shows a known coating on a fibrous nonwoven support.

2 schematically shows a preferred coating process.

3 shows a preferred coating apparatus.

4 shows a preferred coating on a fibrous nonwoven support.

5 shows a particle coater of the present invention.

6 and 6a show details of the particle coater of FIG. 5.

7 shows an alternative embodiment of a particle coater.

8A, 8B, 8C and 8D show various multiple particle coater geometries.

9 is a copy of a known foam abrasive product.

10 is a copy of a photograph of a preferred foam abrasive product.

The organic support used as the support material for the abrasive particles may be a fiber support such as a woven, knitted or nonwoven fabric. For example, the fiber support may be woven, knitted or nonwoven, such as air-laid, carded, stitch-bonded, spunbonded, wet-laid or And melt-blown structures. Alternatively, thermoplastic, thermoset or thermoplastic elastomer foams can be used as the organic support. When foam structures are used, continuous bubble or network foam structures are preferred.

In one embodiment, the organic support is an open lofty three-dimensional nonwoven comprising a nonwoven web and a fiber adhesive treatment (commonly known as a “prebonded” adhesive). Nonwoven webs suitable for use in the products of the present invention are air-laid, carded, stitch-bonded, spunbonded, wet-laid or melt- It can also be made in a melt-blown structure. Preferred nonwoven webs are the open lofty three-dimensional airflow nonwovens described in US Pat. No. 2,958,593. The webs may be made of any suitable fiber, such as nylon, polyester, etc., that can withstand the curing temperature at which the adhesive is heated. Can be. Polyester fibers are preferred due to their compatibility with suitable adhesives and relatively low water absorption and thus low sensitivity to ionic contamination. The fibers in the web are preferably tensile and crimped, but may also be continuous filaments formed by an extrusion process such as described in US Pat. No. 4,227,350.

Fibers used in the production of nonwoven webs include both natural and synthetic fibers and mixtures thereof. Synthetic fibers include polyester (e.g. poly (ethylene terephthalate)), nylon (e.g. poly (hexamethylene adipamide), polycaprolactam), polypropylene, acryl (formed from polymers of acrylonitrile), rayon, Preferred are cellulose acetate, polyvinylidene chloride-vinyl chloride copolymer, vinyl chloride-acrylonitrile copolymer and the like. Natural fibers include fibers of cotton, wool, jute and hemp. An important consideration in the selection of the fiber is that the fiber should not melt or degrade at the melting point or curing temperature of the adhesive used as the fiber and abrasive binder. The fibers used may be fibers that have never been used, or may be waste fibers recycled from garment cutting, carpet making, fiber making or textile processing and the like. The fibrous material may be homogeneous fibers or composite fibers, such as bicomponent fibers (eg, co-spun sheath-core fibers).

The fineness or linear density of the fibers used can vary over a wide range depending on the desired result. Coarse fibers are generally more helpful in making pads for rough polishing operations, while finer fibers are more suitable for less aggressive polishing operations. Preferred fibers are those having a linear density of about 1 to 25 denier, but for example finer or coarser fibers may be used depending on the intended use for the final abrasive product. Those skilled in the art will appreciate that the invention is not limited by the nature of the fibers used or by their respective lengths, deniers, and the like.

The nonwoven web can be formed by a commonly available RANDO-WEBBER device, such as manufactured by Rando Machine Co. of Macedon, NY. Using such a treatment apparatus, the fiber length should normally be maintained within about 1.25 cm to about 10 cm. However, using other types of conventional web forming apparatus, it is possible to use fibers of different lengths or combinations thereof to form a nonwoven web. The thickness of the fibers is not particularly limited (apart from processing considerations) so long as the ultimate elasticity and toughness ultimately desired in the resulting web is considered. When using a Lando-Weber device, the fiber thickness is preferably in the range of about 25 to about 250 micrometers.

The fibers may be curly, crimped and / or straight. However, it is desirable that all or substantial amounts of fibers be crimped to obtain a three-dimensional structure with maximum loft and opening. It is understood that crimping may be unnecessary if the fibers are easily interlaced with each other to form and maintain a very open lofty relationship in the formed web.

The fibers may be used in the form of a web, batt or tow. As used herein, "tansom" refers to a plurality of airflow webs or similar structures.

To arbitrarily enhance nonwoven abrasive products, it may be desirable to promote fiber bonding within the nonwoven web, resulting in a higher structural strength of the product. Such a fiber treatment may be imparted to the web before or after the adhesive adheres the abrasive particles to the fiber surface using a make adhesive, preferably as a separate treatment. Adhesives known as “prebonded” resins without abrasive components can be used to further integrate the nonwoven web. Using a known coating or spraying technique, a resinous adhesive is applied to the fibers of the airflow web as a liquid coating, and then the adhesive is cured (eg by thermal curing), whereby the fibers of the web at each other are contacted with each other. Combine. Suitable adhesive materials that can be used in this regard are known and include those described in US Pat. No. 2,958,593. When melt bondable fibers are included in the structure of the nonwoven web, the fibers may adhere to each other at their mutual contact point by appropriately heat treating the web to melt at least one component of the fiber. The molten component acts as an adhesive, and upon cooling, the molten component solidifies again, thereby forming a bond at the mutual contact point of the fibers of the web. The inclusion of melt-bondable fibers (such as those described in US Pat. No. 5,082,720) in the nonwoven web may or may not be accompanied by the application of a prebonded resin, as is known to those skilled in the art. The selection and use of melt bondable fibers, the selection and application of prebonded resins, and the conditions necessary for bonding nonwoven fibers to one another (eg, by melt bonding or by prebonding resin) are typically practiced in the art. It is within the technical scope.

As mentioned above, the fibers are bonded to each other at their mutual contact point to provide an open, low density, lofty web with the gaps between the fibers substantially not filled with resin or abrasive. For typical applications, the void volume of the final nonwoven abrasive product is preferably in the range of about 75% to about 95%. At lower pore volumes, nonwoven products tend to exhibit higher clog-ups that reduce the polishing rate and prevent cleaning the web by flushing. If the void volume is too high, the web may lack adequate structural strength to withstand the stresses associated with cleaning or polishing operations.

It is also understood that the organic support may comprise an open tow of filaments in a substantially parallel arrangement as a nonwoven flexible abrasive article. In such embodiments, a nonwoven polishing pad may be formed, for example, by coating the open filament tow with an adhesive, prior to or during the deposition of abrasive particles on the tow. The adhesive is then heat treated to fuse the abrasive particles to the filament surface as described above.

The gas phase in the foamed polymer or foam is distributed in gaps or voids called bubbles. If the bubbles are interconnected such that gas can pass from one bubble to another, the foam is called a continuous bubble. Conversely, if the bubbles are separated and each gas phase is independent of the gas phase of the other bubbles, the foam is called an independent bubble. When the proportion of continuous bubbles in the foam is higher than that of independent bubbles, the foam is a continuous foam foam. The independent bubble content of the foam may be measured by the air flow manometer described in ASTM method D3574.

In general, elastic and flexible foam supports having continuous bubbles having a coatable surface on at least one support surface can be used in the abrasive articles of the present invention. Preferred foam supports have between about 4 and about 100 pores (ppi) per inch (average pore diameters between 6 and 0.25 mm). Foam supports having pores greater than about 100 ppi have a surface that acts as a solid surface. Such solid surfaces may be coated by the method of the present invention, but such foam supports will not be able to maintain the properties of the uncoated foam supports due to non-uniform application of resins and particles. Useful foam supports include those made from synthetic polymeric materials, such as polyurethane, foam rubber and silicone, and natural sponge materials.

The thickness of the foam support is only limited by the desired end use of the flexible abrasive product. Preferred foam supports have a thickness in the range of about 1 mm to about 50 mm.

Preferred foam materials include polyester urethane materials, have uniform voids, and have an open network bubble structure. Such preferred foams provide the necessary product flexibility and polishing performance and reduce the tendency for contamination.

As described in more detail below, an adhesive layer is formed from applying a resinous make coat precursor or a first resin to a porous support, and optionally from a size coat precursor or a second resin applied over the make coat precursor and the abrasive particles. Preferably, upon curing, an adhesive layer is formed from a make coat precursor and a size coat precursor that have been applied to the porous support with a coating weight that provides the adhesion necessary to strongly bond the abrasive particles to the support. The make coat and size coat precursor may optionally be foamed or foamed before being applied to the porous support. In the final product of the present invention, the adhesive layer provides a thin resin coating over the abrasive particles without embedding the particles in the resin. When viewed under a microscope, for example, it was observed that the individual particles are fixed to the coatable surface of the support and extend outward from the outer surface of the coatable surface. In this structure, the abrasive particles are positioned so that the article has an immediate polishing efficiency upon initial application of the final product. In addition, the particles adhere strongly to the coatable surface of the crevice in order to provide an abrasive product with a satisfactory working life.

Suitable make coat precursors for use in the present invention are coatable and curable adhesive binders, and may comprise one or more thermoplastic, or preferably thermosetting resinous adhesives. Preferred adhesive binders include polyurethanes due to their flexibility, toughness, and the provision of a minimal cause for contamination and color tone. Other resinous adhesives suitable for use in the present invention include phenolic resins, aminoplast resins with suspended α, β-unsaturated carbonyl groups, epoxy resins, ethylenically unsaturated resins, acrylated isocyanurate resins, urea-forms. Aldehyde resins, isocyanurate resins, acrylated urethane resins, acrylated epoxy resins, bismaleimide resins, fluorene-modified epoxy resins, and combinations thereof. However, the selection of such resins should be done very carefully to avoid introducing undesirable amounts of contaminants or creating brittle coatings that tend to produce undesirable particulates. Similarly, catalysts and / or curing agents may add to the potential for contamination of the adhesive binder, so they should be carefully selected. The make coat dry addition amount will typically be between 50 g / m ² and 170 g / m ² .

The epoxy resin has an oxirane ring and is polymerized by ring opening. Such epoxide resins include monomeric epoxy resins and polymeric epoxy resins. Such resins can vary greatly depending on the nature of their backbone and substituents. For example, the backbone may be of the type normally associated with epoxy resins, and the substituents thereon may be groups that do not have active hydrogen atoms that react with the oxirane ring at room temperature. Representative examples of acceptable substituents include halogen, ester groups, ether groups, sulfonate groups, siloxane groups, nitro groups and phosphate groups. Examples of some preferred epoxy resins are 2,2-bis [4- (2,3-epoxypropoxy) phenyl) propane (diglycidyl ether of bisphenol a) and trade names EPON 828, EPON 1004 and EPON Materials commonly available as 1001F (commercially available from Shell Chemical Co.), DER-331, DER-332 and DER-334 (commercially available from Dow Chemical Co.) . Other suitable epoxy resins are the glycidyl ethers of phenol formaldehyde novolacs (for example DEN-431 and DEN-428 available from Dow Chemical Company).

Examples of ethylenically unsaturated bond precursors include aminoplast monomers or oligomers with suspended alpha, beta unsaturated carbonyl groups, ethylenically unsaturated monomers or oligomers, acrylated isocyanurate monomers, acrylated urethane oligomers, acrylated epoxy monomers Or oligomers, ethylenically unsaturated monomers or diluents, acrylate dispersions or mixtures thereof.

The aminoplast binder precursor has one or more suspended alpha, beta-unsaturated carbonyl groups per molecule or oligomer. Such materials are described in US Pat. Nos. 4,903,440 and 5,236,472.

The ethylenically unsaturated monomer or oligomer may be monofunctional, difunctional, trifunctional or tetrafunctional or higher functional. The term acrylate includes both acrylates and methacrylates. Ethylenically unsaturated binder precursors include monomers and polymeric compounds containing atoms of carbon, hydrogen and oxygen and optionally nitrogen and halogens. Oxygen or nitrogen atoms or both are generally present as ether, ester, urethane, amide and urea groups. The ethylenically unsaturated compound preferably has a molecular weight of less than about 4,000, preferably a compound containing an aliphatic monohydroxy group or an aliphatic polyhydroxy group and an unsaturated carboxylic acid such as acrylic acid, methacrylic acid, itaconic acid, crotonic acid, iso It is ester made from reaction with crotonic acid, maleic acid, etc. Representative examples of ethylenically unsaturated monomers include methyl methacrylate, ethyl methacrylate, styrene, divinyl benzene, hydroxy ethyl acrylate, hydroxy ethyl methacrylate, hydroxy propyl acrylate, hydroxy propyl methacrylate, Hydroxybutyl acrylate, hydroxybutyl methacrylate, vinyl toluene, ethylene glycol diacrylate, polyethylene glycol diacrylate, ethylene glycol dimethacrylate, hexanediol diacrylate, triethylene glycol diacrylate, trimethylol Propane triacrylate, glycerol triacrylate, pentaerythritol triacrylate, pentaerythritol trimethacrylate, pentaerythritol tetraacrylate and pentaerythritol tetramethacrylate. Other ethylenically unsaturated resins include monoallyl, polyallyl and polymethallyl esters and amides of carboxylic acids such as diallyl phthalate, diallyl adipate and N, N-diallyl adipamide. Still other nitrogen containing compounds include tris (2-acryloxyethyl) isocyanurate, 1,3,5-tri (2-methylacryloxyethyl) -s-triazine, acrylamide, methylacrylamide, N-methyl -Acrylamide, N, N-dimethylmethylamide, N-vinylpyrrolidone and N-vinyl-piperidone.

Isocyanurate derivatives with one or more suspended acrylate groups and isocyanate derivatives with one or more suspended acrylate groups are described in US Pat. No. 4,652,274. Preferred isocyanurate materials are triacrylates of tris (hydroxy ethyl) isocyanurate.

Acrylate urethanes are diacrylate esters of hydroxy terminated isocyanate extended polyesters or polyethers. Examples of commercially available acrylated urethanes are from UVITHANE 782 (available from Morton Chemical) and CMD 6600, CMD 8400 and CMD 8805 (UCB Radcure Specialties). Available). The acrylated epoxy is a diacrylate ester of an epoxy resin, such as a diacrylate ester of a bisphenol A epoxy resin. Examples of commonly available acrylated epoxies include CMD3500, CMD3600 and CMD3700, all of which are available from UCB Radcure Specialties.

Examples of ethylenically unsaturated diluents or monomers can be found in US Pat. Nos. 5,667,842 and 5,236,472. In some cases, such ethylenically unsaturated diluents are useful because of their tendency to be compatible with water.

Further details regarding acrylate dispersions can be found in US Pat. No. 5,378,252.

It is also within the scope of the present invention to use partially polymerized ethylenically unsaturated monomers in make or size coat precursors. For example, acrylate monomers can be partially polymerized and incorporated into make coat precursors. The degree of partial polymerization must be controlled so that the resulting partially polymerized ethylenically unsaturated monomer does not have an excessively high viscosity and as a result the precursor becomes a coatable material. An example of an acrylate monomer that can be partially polymerized is isooctyl acrylate. It is also within the scope of the present invention to use combinations of partially polymerized ethylenically unsaturated monomers with other ethylenically unsaturated monomers and / or condensation curable resins.

In the manufacture of hand pads for use in the cleanroom applications mentioned above, the adhesive materials used as make coat precursors in the present invention are described in Kirk-Othmer, Encyclopedia of Chemical Technology, 3rd edition, John Wiley & Sons, 1981, New York , Vol. 17, pp. 384-399, and thermosetting phenol resins such as resol and novolak resins. Resol phenolic resins are prepared using an alkaline catalyst and formaldehyde having a molar excess, typically formaldehyde to phenol molar ratio of 1.0: 1.0 to 3.0: 1.0. The novolak resin is prepared using a formaldehyde to phenol molar ratio of less than 1.0: 1.0 under acid catalyst. Typical resol resins useful in the manufacture of the products of the present invention include from about 0.75% (weight) to about 1.4% free formaldehyde; About 6% to about 8% free phenol; It contains about 78% solids and the remainder is water. The pH of this resin is about 8.5 and the viscosity is about 2400 to about 2800 centipoise. Commercially available phenolic resins suitable for use in the present invention include trade names DUREZ and VARCUM (obtained from Occidental Chemicals Corporation, Northern Tona Wonder, NY); RESINOX (available from Monsanto Corporation); And those known as AROFENE and AROTAP (both available from Ashland Chemical Company); As well as the resol precondensates available under the trade name BB077 (available from Nest Resins, a branch of Nest Canada Inc., Mississauga, Canada). Organic solvents may be added to the phenolic resin as desired or desired.

Preferred adhesive materials used in the flexible abrasive article of the present invention are preferably polyurethanes, such as Crompton & Knowles Corporation of Stamford, Connecticut under the trade names ADIPRENE BL16 and Adiprene BL31. It includes those commonly available from.

The size coat precursor may be the same as the make coat precursor mentioned above or may be different from the make coat precursor. The size coat precursor can be any number mentioned above, such as phenolic resins, urea-formaldehyde resins, melamine resins, acrylate resins, polyurethane resins, epoxy resins, polyester resins, aminoplast resins, and combinations and mixtures thereof. It may also include oily or colloidal adhesives. Preferably, the size coat precursor comprises a resinous adhesive similar or identical to the adhesive used in the make coat precursor. More preferably, the size coat precursor comprises a thermosetting resin or a radiation curable resin. The size coat precursor may be foamed prior to application to the make coat in order to reduce the wet additional weight of the resin so that the abrasive particles are not embedded in the resin coating and are not helpful for use in the initial application of the final product. The size coat precursor is preferably applied to the porous support to provide an additional weight comprising abrasive particles with a thin, substantially uniform coating while preventing the particles from being embedded under the resin, which is typically about 50 g / m ^2. To about 200 g / m ² . However, the specific additional weight depends on several factors such as the nature of the porous support as well as the nature of the resin used. Determination of the appropriate size coat additional weight is within the skill practice in the art. Preferred size coats are polyurethanes.

Useful abrasive particles suitable for inclusion in the abrasive articles of the present invention include known finer and larger abrasive particles, all of which have a median particle diameter of 1 micron to about 600 microns, and intermediate particles of about 10 microns to about 100 microns. Diameter is preferred. More preferably, such fine abrasive particles are provided in a distribution of particle sizes having a median particle diameter of about 30 microns to about 60 microns. Among the various kinds of abrasive materials useful in the present invention are aluminum oxide particles such as ceramic aluminum oxide, heat-treated aluminum oxide and white-fused aluminum oxide; As well as silicon carbide, alumina zirconia, diamond, ceria, boron nitride tools, garnet, ground glass, quartz and combinations thereof. Useful abrasive particles may include softer and less aggressive materials such as thermoset or thermoplastic polymer particles, as well as crushed natural materials such as, for example, nut shells. Chemically active particles may also be included in the abrasive article, unless the chemically active particles add an unpleasant level of contaminants.

Those skilled in the art will understand that the choice of particle composition and particle size depends on the desired end use of the final abrasive product, taking into account the nature of the workpiece surface treated by the product and the desired abrasive effect. Preferably, the fine abrasive particles for inclusion in the article of the present invention include materials having a Mohs hardness of about 5 or greater, but softer particles may be suitable in some applications, and the present invention may be suitable for certain hardness values. It should not be construed as limited to excited particles. The particles are added to at least one of the first or second surfaces of the porous support to provide a particle loading suitable for the desired end use of the final product. Abrasive particles are applied to the porous support to provide additional weight within the range of about 209 to 628 g / m ² (about 50 to 150 particles / 24 in ² ). Preferred abrasive particles are particles of white alumina fused due to relatively low cost and small amounts of contaminants. More preferred abrasive particles are fused white alumina containing small amounts of sodium, sodium oxide or other sodium derivatives.

Make coat precursors or size coat precursors or both may contain any additives such as fillers, fibers, lubricants, grinding aids, wetting agents, surfactants, pigments, dyes, binders, photoinitiators, plasticizers, suspending agents, antistatic agents, and the like. It may be. However, the types and amounts of additives with the potential to increase the presence of contaminants should be strictly avoided. As known to those skilled in the art, the type and amount of additives are selected to provide the desired properties.

Organic solvents and / or water may be added to the precursor composition to change the viscosity prior to coating, where such solvents need to be chosen so as not to add contamination to the contamination level of the resulting product. The choice of particular organic solvent and / or water is believed to be within the skill set in the art and depends on the thermosetting resin used in the make or size precursor and the amount of resin used.

As shown in FIG. 2, in the manufacture of the product of the present invention, a porous support 100 having a first side 104 and a second side 106 is fed into the device 14. First, the porous support 100 is passed through a coater 20 for applying an adhesive or a make coat precursor to the porous support 100. The coater 20 may include suitable coaters known in the art, such as spray coaters, roll coaters, dip coaters, knife over roll coaters, and the like. When applying the make coat precursor described below, the preferred coater 20 comprises a double roll coater through which the porous support 100 passes through a nip formed by two opposing rollers. Preferably, the pressure of the roller is adjusted to control penetration of the make coat precursor to the thickness of the porous support. Suitable coaters are known in the art. The make coat precursor is applied from the pan to the lower roller as is known in the art. Another suitable arrangement for applying the make coat precursor to the porous support is to apply the make coat precursor to the bottom roll or both rolls of the dual roll coater with a slot die, the make coat precursor with a slot die before entering the nip of the double roll coater. Is applied directly to the porous support, applying a make coat precursor with a slot die without using a roll coater and optionally evacuating the porous support on the opposite side of the slot die, both sides of the porous support with opposing slot dies. Applying, but not limited to, applying a make coat precursor to a cotton and then passing or not passing the porous support through a roll coater, and applying a hose or a conduit across the porous support. It doesn't happen.

After exiting the first adhesive coater 20, the porous support 100 passes through the first particle coater 22. The first particle coater 22 is preferably arranged to apply fine abrasive particles to the first surface 104 of the porous support. As will be described further below, the abrasive particles penetrate from the surface 104 to some depth within the porous support 100 depending on the nature of the bubbles of the porous support. When desiring to apply abrasive particles to the second side 106 of the porous support 100, the porous supports may be rollers 24a and 24b to re-orient the porous support with the second side 106 facing up. Pass it up. The porous support is then passed through any second particle coater 26 arranged to apply abrasive particles to the second side 106 of the porous support 100. Preferably, the second particle coater 26 has a structure similar to the first particle coater 22. However, for certain applications, it may be desirable to use a second coater 26 of a different type or arrangement than the first particle coater 22. The second abrasive particle coater 26 may also apply abrasive particles having the same or different composition and / or size as the abrasive particles applied by the first abrasive particle coater 22. Electrostatic coating techniques may also be used to coat the particles onto the porous support.

After applying the fine abrasive particles to at least the first surface 104 and optionally the second surface 106 of the porous support 100, the porous support 100 is preferably exposed to a heat source (not shown), such as an infrared lamp or oven. The make coat precursor is heated to the extent necessary to at least partially cure the resin. In some applications, it may be desirable to fully cure the make coat precursor at this stage. Heating can be performed using a heat source that provides sufficient heat distribution and airflow. Examples of suitable heat sources include forced draft ovens, convection ovens, infrared heat, and the like. The use of radiation or actinic energy is also within the scope of the present invention. For heat-activatable thermosetting resins, it is desirable to heat them for a time sufficient to remove residual solvent and initiate partial curing of the resin.

In a preferred embodiment, in order to apply any but desired size coat precursor to the porous support 100 after exiting the second abrasive particle coater 26, the porous support 100 is optionally subjected to a second adhesive or size precursor coater 28. Pass it through. Preferably, the size precursor coater is in the same batch as the make precursor coater 20. For some applications, it may be desirable to use a coater 28 in a different batch than the first coater 20. In some applications, it may be desirable not to add a size coat.

A preferred embodiment of the first particle coater 22 is shown in more detail in FIG. 3. The porous support 100 is conveyed through the coater 22 by a carrier belt 30 passing around rollers 32a and 32b, at least one of which is a drive roller. The porous support 100 passes through the particle spray booth 34. Booth 34 includes a first side 36, a second side 38, an upper 40 and a lower 42. Booth 40 also includes a front and back not shown. The first side 36 includes an introduction slot 44a of a size and shape into which the porous support 100 and the carrier belt 30 can enter the booth 34. The second side 38 includes a discharge slot 44b of size and shape that allows the porous support 100 and the belt 30 to exit the booth 34. Slots 44a and 44b are located near the bottom of faces 36 and 38, respectively. The particle atomizer 46 is mounted through the opening in the upper part 40 of the booth 34, and the deflector 48 is attached to the outlet 47 of this atomizer. At this point a porous support 100 comprising a make coat precursor thereon is carried by the belt 30 through the booth 34. As the porous support passes from inlet slot 44a to outlet slot 44b, particle sprayer 46 introduces particles 102 into the booth to coat the first side 104 of the porous support with abrasive particles. As described below, the particles 102 penetrate into the porous support 100 to some depth. Now, the porous support 100 comprising abrasive particles attached to the porous support by the make coat precursor is discharged from the booth 34.

In one preferred embodiment, particle atomizer 46 is supplied with abrasive particle / air mixture from fluidized bed 52. Abrasive particles 102 are flowed in layer 52 by fluidizing air (from a suitable source, not shown), which is introduced into the bed through flowing air inlet 53.

At the top of the fluidized bed 52 is a venturi inlet 56 known in the art. In the illustrated embodiment, venturi 56 receives primary air from a suitable source through primary air inlet 58. Primary air is passed through venturi (56) and a mixture of fluidized particles and air is drawn through draw tube (54) extending from venturi (56) into fluidized bed (52). Optionally, secondary air may be added to the venturi inlet 56 via the secondary air inlet 60. After attracting particles into the venturi to assist in delivering the fluidized abrasive particle / air mixture to the sprayer 46 through the particle hose 64 extending from the venturi outlet 62 to the inlet of the particle sprayer 46, 2 Primary air is added to the flow of fluidized abrasive particles.

A deflector 48 mounted at the outlet 47 of the particle atomizer 46 directs the fluidized abrasive particle / air mixture in a new direction. Deflector 48 includes a deflector top 49 (shown in FIGS. 5 and 6), a deflector bottom 50, and a deflector wall 51. In one preferred arrangement, the deflector bottom 50 has a diameter of 32 mm (1.26 inches), the lower rim of the deflector extending 20 mm (0.79 inches) from the outlet of the spray gun and 155 mm (6.1 inches) above the porous support 100. Is fixed at its height. Of course, other arrangements are within the scope of the present invention. For example, the size of the deflector, the shape of the deflector, the perimeter of the wall 51, the number and location of the particle sprayers 46, the deflector height above the porous support, the speed of the porous support 100, and in the particle / air mixture The air pressure and the ratio of the abrasive particles may be changed respectively. These parameters may be varied to achieve the desired additional weight of abrasive particles, the desired degree of penetration of the abrasive particles into the porous support 100, or the desired uniformity of the abrasive particles 102 over the porous support 100.

In one preferred embodiment, the nebulizer 46, fluidized bed 52 and regulator (not shown), together with the substantially round deflector 48 as shown in FIG. 5, is an Illinois tool in Indianapolis, Indiana, USA. Commonly available systems known as MPS 1-L Manual Powder Systems, including Model PG 1-E Manual Enamel Powder Gun, available from Gema of Illinois Tool Works Company to be.

In another preferred embodiment, the abrasive particle spraying device is of the type commonly available from Binks Manufacturing Company (Sames) of Franklin Park, Illinois, USA, and 50 lb. with a standard powder pump. Fluidized bed, GCM-200 Gun Control Module, SCM-110 Stability Control Module, STAJET SRV Type 414 Gun.

Another preferred embodiment of the particle atomizer 46 is shown in FIGS. 5 and 6. In this embodiment, the nebulizer comprises an elongated tube 66 having an outlet 47 at one end and an inlet 68 at the opposite end of the tube. In use, this embodiment of the nebulizer 46 has an abrasive particle / air mixture hose attached to the inlet 68, as illustrated with respect to the embodiment of FIG. 5 mentioned above. The embodiment of the sprayer 46 shown in FIGS. 5 and 6 is mounted to the spray booth 34 and operated as described with respect to the embodiment of the particle coater 22 shown in FIG. 3.

5 and 6, the nebulizer 46 includes a particle deflector 48 mounted to the outlet 47 of the tube 66. The deflector 48 is mounted to the tube 66 by any suitable mounting means. In one preferred embodiment, the deflector stem 70 comprises a base 72 comprising a generally rectangular plate having a first end 74 and a second end 76. The base 72 is sized and shaped such that the slot 69 fits snugly at the distal end of the tube 66 near the outlet 47. Base 70 may be permanently or removably mounted to tube 66. In the illustrated embodiment, the base 72 is removable from the slot 69 by springs, clips or other suitable fasteners (not shown) attached to the holes 78 at the first and second ends of the base 72. Is fixed. A threaded rod 80 extending from the base 72 has a first end 82 attached to the base (eg, by soldering) and a second end 84 extending beyond the outlet 47 of the tube 66. The threaded rod 82 is shaped to engage the quasi-screw hole in the top 49 of the deflector 48. This allows the position of the deflector 48 to be conveniently adjusted relative to the outlet 47 of the tube 66 by rotating the deflector 48. This makes it possible to change the direction of motion of the particles 102 exiting the nebulizer 46 as described above. The deflector 48 also includes a bottom 50, an opposite top 49 and a deflector wall 51 extending between the top 49 and the bottom 50.

An alternative embodiment of the nebulizer 46 is shown in FIG. 6A. In this embodiment, the threaded rod 80 is elongated and includes an tapered end 82 to direct the flow of abrasive particles through the tube 66. The pin 73 extends through the hole 75 in the wall of the tube 66 and extends through the hole in the rod 80 to mount the rod 80 to the sprayer 46. In one embodiment, the tapered end 82 of the rod 80 ends at the inlet 68. In other embodiments, the end 82 may extend beyond the inlet 68, or the inlet may extend beyond the end 82 of the rod. The deflector 48 is mounted to the screw end 84 as described above.

Tube 66 and deflector 48 should be sized and shaped to provide a desired uniform spray pattern of abrasive particles 102. In one preferred embodiment, tube 66 is approximately 61 cm (24 inches) long, has an inner diameter of 1.08 cm (0.425 inch) and an outer diameter of 1.27 cm (0.5 inch), and consists of stainless steel. It is understood that other sizes and materials of the tube 66 are also within the scope of the present invention.

Another preferred embodiment of the abrasive particle sprayer 46 is shown in FIG. 7. In this embodiment, the nebulizer 46 includes rotating first and second circular discs 90 and 91, respectively, connected by studs 93. The second disc 91 has a hole 92 in its center. The second disc is connected to the central hole and the concentric axis of rotation 94. The rotary shaft 94 is rotatably mounted on the outside of the fixed feed tube 95 by a bearing 98, so that the rotary shaft 94 is concentric with the fixed feed tube 95. In this way, the axis of rotation 94, first plate 90 and second plate 91 can rotate together as a unit around the fixed feed canal 95. The rotating shaft 94 can be driven by any suitable power means, such as an air motor (not shown). Feed tube 95 includes an inlet 96 and an outlet 97. In one preferred embodiment, the inlet 96 of the feed tube 95 is attached to the abrasive particle / air mixture hose 64 and the top of the particle booth 34 as described with respect to the embodiment of FIG. 40) is equipped with a particle atomizer 46. In this arrangement, the particle atomizer 46 is supplied with fluidized abrasive particles from the fluidized bed 52. In a variant of this embodiment, a vibration feed may be used instead of the fluidized bed 52. A vibrating feeder is connected into the inlet 96 of the feed canal 95 to feed abrasive particles.

In operation, the rotary shaft 94 is driven such that the plates 90 and 91 can be rotated. Fine abrasive particles pass through the supply pipe 95 and are discharged from the outlet 97. The tube outlet 97 is positioned through the hole 92 in the second plate 91 so that the abrasive particles enter the space between the first and second plates 90, 91. The abrasive particles strike the top surface of the rotating plate 90 and are dispersed through the outlet 47 in a direction generally parallel to the faces of the first and second plates 90, 91. As described with respect to the embodiment described above, the particles preferably form a cloud of haze that is deposited by sedimentation that occurs due to gravity being applied onto the surface of the porous support 100. In one preferred embodiment, particle atomizer 46 comprises Binks EPB-2000 (commonly available from the Binks Manufacturing Company of Franklin Park, Illinois, USA), and the abrasive particles in Ohio, USA. The particle nebulizer is fed by a vibratory pre-feeder, commonly available as "Type 151" from Cleveland Vibratory Company, Cleveland. It is desirable to drive the plates 90, 91 of the particle sprayer at 6,000 to 9,000 RPM, but slower or faster speeds are also within the scope of the present invention. In order to provide the desired abrasive particle spray pattern, the desired abrasive particle additional weight, or the desired degree of penetration of the abrasive particles into the porous support 100, the atomizing particle feed rate, type of particle feeder, or rotational speed of the plate may be selected. have.

Common to the preferred embodiments described herein, the particle nebulizer approaches or exceeds the flow direction of the particles 102 exiting the nebulizer from the direction perpendicular to the porous support 100 to a plane parallel to the porous support 100. Means to change direction. This direction is described with respect to the portion that closely surrounds the outlet 47 of the particle sprayer 46. Thereafter, the fine particles 102 are preferably dispersed into the particle mist in the booth 34. The particles then settle out of the mist onto the porous support under the influence of gravity. That is, in one preferred embodiment of the method of the present invention, just before the particles are attached to the porous support 100, gravity has a significant effect on the movement of the abrasive particles relative to the momentum imparted by the particle sprayer 46. . In some applications, the momentum imparted by the particle nebulizer 46 has little or no effect on the motion of the particles 102 immediately before the particles adhere to the porous support 100. In other applications, for example, when abrasive particles 102 are desired to penetrate significantly into porous support 100, downward momentum imparted to particle 102 by nebulizer 46 causes particles to adhere to the porous support. Parameters and shapes of the device may be selected to have a significant impact on the momentum of the particles immediately before.

In the embodiment described with respect to FIGS. 3, 5 and 6, the means for directing the flow of particles 102 exiting particle atomizer 46 is deflector wall 51 of deflector 48. Preferably, the position of the deflector 48 with respect to the outlet 47 of the particle atomizer may be varied in order to change the flow direction of the abrasive particles 102 exiting the particle atomizer. Without the deflector 48, it is understood that the abrasive particles exiting the particle sprayer 46 generally move parallel to the long axis of the sprayer, ie generally perpendicular to the porous support 100. In general, the closer the walls 51 and bottom 50 of the deflector are to the outlet 47, the greater the direction of movement of the particles 102 from the direction perpendicular to the porous support 100. Further movement of the wall 51 and the bottom 50 of the deflector from the outlet 47 reduces the amount of change in the direction of movement of the particles from perpendicular to the porous support 100. In the embodiment described with respect to FIG. 7, the structures for directing the flow of abrasive particles are rotating plates 90, 91.

In some applications, it may be desirable to place a hard insert, such as a ceramic insert, in a part of the device 14 that tends to wear out when prolonged flow of abrasive particles through the part. It may be desirable to be located, for example, in the particle atomizer 46, the venturi inlet 56 and the deflector 48. Such inserts extend the useful life of certain components of the device 14 but are not expected to have a significant effect on the performance of the device.

For some applications, it is desirable to use multiple particle atomizers 46 in a single spray booth 34. Preferably, each particle atomizer is of a similar form, but it is understood that different types of particle atomizers can be used in a single booth. The particle sprayer 46 should be arranged in a pattern that uniformly coats the abrasive particles 102 on the porous support 100 as the porous support passes through the booth 34. This may be accomplished by arranging multiple particle sprayers 46 such that each position across the width of the porous support 100 is traversed through the same number of spray patterns caused by each particle sprayer 46. An example particle atomizer arrangement is shown schematically in FIGS. 8A-8D. These figures are schematic top views of the porous support 100 passing underneath the spray pattern 45 produced by the particle sprayer 46 mounted on the top 40 of the booth 34 (not shown). In order to obtain the desired coating pattern of abrasive particles 102 on the porous support 100, the respective flow rates of the plurality of atomizers 46 may be varied, or different types of atomizers 46 may be used. In addition, the particle sprayer 46 can be rocked or reciprocated to achieve the desired spray pattern as is known in the art.

When using multiple particle atomizers 46, a number of particle coaters 22 similar to those shown in FIG. 3 may be used, with each particle atomizer being awarded abrasive particles in each fluidized bed 52. In some applications, it is desirable to feed multiple particle atomizers 46 from a single fluidized bed 50. In this arrangement, multiple Venturi injectors 56 are mounted in a single fluidized bed. In an alternative arrangement, a number of volume control auger feeders are mounted on the side wall of the fluidized bed to derive the desired velocity of fluidized abrasive particles / air mixture from the fluidized bed 50. The operation and structure of these feeders is well known and need not be mentioned further. Each auger feeder deposits abrasive particles in the venturi injector 56 as described above. Each Venturi injector 56 is connected to an abrasive particle / air mixture hose 64 to deliver the abrasive particle / air mixture to the particle atomizer 46 as described above. In one preferred embodiment, the fluidized bed 50 equipped with a plurality of auger feeders is of the type commonly available as POWER DELIVERY CONTROL UNIT from Gema of the Illinois Tool Works Company, Indianapolis, Indiana, USA. . It is also within the scope of the present invention that the auger feeder feeds abrasive particles from a volume feeder of the type commonly available as DRY MATERIAL FEEDER from AccuRate, Whitewater, WI. .

It is also within the scope of the present invention to include additional particle atomizers arranged to spray abrasive particles onto the porous support 100 with sufficient force to penetrate more into the center of the porous support. Such further particle atomizers, in the arrangement of the particle atomizers 46, or in the form arranged to spray the porous support 100 before or after the porous support passes under the atomizer 46, are described above. May be included in the spray booth 34. Such additional nebulizers may be arranged in a second particle spray booth in front of or behind the nebulizers 22, 26 described above. Preferably, further sprayers are arranged to deposit abrasive particles on the porous support in front of sprayer 46 so as not to interfere or interrupt the advantageous spray pattern achieved by sprayer 46. As described herein, for a longer service life abrasive product, such as to provide a porous support 100 having advantageous fine particle distribution at the surfaces 104, 106, with particles at the center of the porous support. Combinations of nebulizers may also be used.

In one preferred embodiment, the porous support 100 has a width of 61 cm (24 inches) from the first corner 107 to the second corner 108, about 3 to 30 m / min (10 to 100 ft / min), More preferably, it is fed through the device 14 at a porous support speed of 16 m / min (52.5 ft / min). The first adhesive coater 20 is a double roll coater, through which the porous support 100 passes through a nip formed by two opposing rollers. As described with respect to FIGS. 5 and 6, the fine abrasive particles 102 are applied by eight particle atomizers 46 and supplied by eight Venturi inlets 56 mounted in the fluidized bed 52. The spray pattern of the injector is generally as shown in Figure 8B. The parameters of the geuma particle coater described above are as follows: flowing air is introduced through the inlet 53 at a pressure of about 2 to 15 psi; Primary air is introduced into the inlet port 58 of the venturi 56 at a pressure of 90 psi or less, preferably 30 to 60 psi; Secondary air is supplied into the inlet 60 at a pressure of 0 to about 90 psi, preferably 0 to about 20 psi. In the same manner as the make coat precursor, the size coating precursor can be applied and cured.

By applying the make coat precursor in the manner described herein, the tendency of the make coat precursor to migrate, concentrate and aggregate is reduced. In this way, the coatable surface of the support can be uniformly coated with the make coat precursor, and the abrasive particles 102 can be coated and attached to the coatable surface in a more uniform distribution. By coating the make coat precursor and the abrasive particles in different steps, the likelihood that the abrasive particles are "embedded" in the make coat is low, as readily occurs in the prior art methods of applying the make coat precursor / polishing particle slurry. In the final product formed by the method and apparatus of the present invention, the size coat provides a thin resin coating over the fine abrasive particles without embedding the particles in the resin. When viewed under a microscope, for example, it is observed that each particle is fixed to the coatable surface of the hole and extends outward from the coatable surface of the hole. In this structure, fine abrasive particles are placed in the product so as to have a polishing efficiency immediately upon initial application of the final product. In addition, the particles are strongly adhered to the coatable surface of the pores of the porous support to provide abrasive particles with a satisfactory working life.

Packing

The abrasive product is preferably packaged in a Class 100 environment consistent with Federal Standard 209 and Military Standard 1246C of Class 100 ParticulateCleanliness Levels.

All packaging materials are warranted for use in such agencies (eg in accordance with military standard 1246C). First, the product is placed in a reduced pressure hood and decontaminated using blowing of ionized air. The product is then packaged with an inner packaging material, the ionized air is blown back to clean and then the outer packaging material wrapped with the outer packaging material.

matter

Foam: polyester polyurethane reticulated foam, 50 bubbles per inch, 0.375 inches (9.52 mm), Illbruck, Inc., Minneapolis, Minnesota, USA

PM ether: propylene glycol monomethyl ether, Lyondell Chemical Company of Houston, Texas

PM acetate: propylene glycol monomethyl ether acetate, Arco Chemical Company of Houston, Texas

BL-16: Oxime-blocked isocyanate terminated polyurethane prepolymer, Crompton & Knowles Corporation, Stamford, Connecticut, USA

BL-31: Oxime-blocked isocyanate terminated polyurethane prepolymer, Cromphton and Noles Corporation, Stamford, Connecticut, USA

PACM-20: Bis (para-aminocyclohexyl) methane, aliphatic amine curing agent, Air Products and Chemicals, Inc., Allentown, PA

Fiber: polyester staples 15 denier x 2 ", type 224, Hoechst Celanese, Salisbury, North Carolina, USA

Mineral A: "P320" SWPL white aluminum oxide, Treibacher from Villach Austria

Mineral B: "220 BM" white aluminum oxide, Graystar, Scotland Bluffon

Mix 1: 62% BL16, 8% PACM20, 30% PM Ether (% Liquid Weight)

Mix 2: 14% BL16, 39% BL 31, 7% PACM20, 40% PM Acetate (% Liquid Weight)

Mix 3: 50% BL31, 8% PACM20, 42% PM Acetate (% Liquid Weight)

Biaxial shaking test

The Biaxial Shake Test was used to determine the tendency of the abrasive product of the present invention to produce particulate residues or releasable particles when vigorously stirred. A 10 cm x 10 cm specimen from the abrasive product tested was placed in a sealable plastic pail. 800 ml of COULTER ISOTON solution was added to the bin. The keg was sealed and safely placed in a biaxial paint can shaker (Red Devil Inc. of Union, NJ) and the shaker was activated for 3 minutes. Then, the vat was opened and the sample was taken out. A 250 ml aliquot solution was transferred to a COULTER MULTISIZER II Separation Particle Counter (Coulter Corporation, Miami, FL) sample flask. A particle counter was set up to perform a 2 ml volume particle analysis using a 100 μm hole tube (for measurement of 2 μm to 100 μm particles). The total particle count was determined and normalized to the sample size to obtain releaseable particles per m ^{2 of} abrasive particles.

Basic analysis

Basic analysis was performed by various methods as shown in the table below.

Sample digest Analytes analysis Reference Lithium borate fusion ASTM D4503 silicon Inductively Coupled Plasma, Mass Spectroscopy USEPA 6010B aluminum Inductively Coupled Plasma, Mass Spectroscopy USEPA 6010B Oxygen barrel ASTM D808, USEPA 5050 halogen Ion chromatography ASTM D4327 sulfur Ion chromatography ASTM D4327 Schoniger Flask Combustion ASTM E442 Fluoride Ion selective electrodes ASTM D3869-79 Wet Ash Decomposition USEPA 3050 salt Inductively Coupled Plasma, Mass Spectroscopy USEPA 6010B potassium Flow Coupled Plasma, Mass Spectroscopy USEPA 6010B lithium Inductively Coupled Plasma, Mass Spectroscopy USEPA 6010B silver Inductively Coupled Plasma, Mass Spectroscopy USEPA 6010B Metal scan Inductively Coupled Plasma, Mass Spectroscopy USEPA 6010B

Dry Schieffer Test

Scuffing tests were used to mimic the abrasive quality of abrasive products on the painted surfaces of typical automobiles. 1/8 inch (3.2 mm) thick, 90-105 mm, available in 48 x 96 inch (1.22 x 2.44 m) sheet under the trade name ACRYLITE from American Cyanamid, Wayne, NJ Test specimens were made from poly (methyl) methacrylate sheet material of Rockwell Ball Hardness. After removing the protective cover from the top of the acrylic plate, double coat of PPG BLACK UNIVERSAL BASE COAT paint (PPG Industries, Inc., Automotive Finishing Department, Cleveland, Ohio), as recommended by the manufacturer. Was applied. PPG Paint DAU-82, Clear (PPG Industries, Inc., Cleveland, Ohio, Automotive Finishing Department, Cleveland, Ohio), with a "flash time" of approximately 30 minutes between each double coat application, as recommended by the manufacturer. 3 double coats of paint over the black base coat. The coated sheet was air dried for about 72 hours. A number of 4 inch (10.2 cm) diameter test specimens were cut from the coated sheet, taking care to minimize splitting of the painted surface. The cut disc was then baked in an oven at 150 ° F. (66 ° C.) for about 16 hours while avoiding contact with the coated surface to completely cure the paint coating. The test specimen was then ready to be tested.

Schiffer's polishing machine with a spring clip holding the plate to securely hold the painted test specimen on the lower swivel and a mechanical paster for fixing the polishing composition on the upper swivel (Fraiser Precision, Gaithersburg, Maryland, USA) The test was carried out on the company (available from Frazier Precision Company). In each test, the counter was set to run 500 revolutions. The 4-inch (10.2 cm) diameter disc of the abrasive product tested was cut and mounted on the upper swivel through a mechanical fastener. If the abrasive products had significantly different contact surfaces from each other, they were marked on the side under test. A prefabricated 4-inch (10.2 cm) diameter painted acrylic disc was weighed to the nearest milligram (W (1)) and mounted on the lower swivel with the painted surface facing up through a spring clip. A 10 lb (4.55 kg) weight was placed on the load bench of the abrasive tester. If the polishing tester is upright for the wet test, stop the water supply. Under sufficient force load, the upper swivel was lowered to contact the painted acrylic disc and the machine was operated. After 500 revolutions, the machine was turned off, the abrasive product was removed from the upper swivel and discarded, and the painted acrylic disc was removed from the lower swivel. By scrubbing with a dry paper towel, free dust or debris was removed from the painted acrylic disc, and the disc was again weighed (W (2)). Record the difference W (1) -W (2) as the "cut" to the nearest milligram.

The test shall not wear the painted acrylic disc to the extent that the underlying black paint is removed. The test was repeated when polishing proceeded through the black layer. If polishing also passes through the black layer in the second trial, a freshly painted acrylic disc with an additional clear coating layer must be produced.

Wet Schiffer Test

1) without applying paint to the acrylic disc; 2) perform 2500 cycles per test; 3) The wet Schiffer test was performed in the same manner as in the dry Schiffer test, except that water drops were applied to the workpiece at a rate of about 1 drop per second during the test.

Examples A, B and C

Foam support

Examples A, B, and C were prepared using continuous bubble polyurethane foam as the support. The compositions of Examples A, B and C are shown in Table 1. The make coat precursor was applied through a two roll coater.

Example A was cured at 177 ° C. for 2 minutes for make coating and 3 minutes for size coating. Example B was cured at 189 ° C. for 4 minutes for make coating and 10 minutes for size coating. Example C was cured at 175 ° C. for 6 minutes for make coating and 12 minutes for size coating.

Example Foam Particles / 24in ² (g / m ² ) Make-mix 1 particle / 24in ² (g / m ² ) Make-Mix 2 Particles / 24in ² (g / m ² ) Size-Mix 1 Particle / 24in ² (g / m ² ) Size-Mix 3 Particles / 24in ² (g / m ² ) Mineral A particle / 24in ² (g / m ² ) Mineral B Particles / 24in ² (g / m ² ) A 62 (259) 44 (184) - 64 (268) - 84 (351) - B 67 (280) - 29 (121) - 26 (109) - 91 (380) C 65 (272) 30 (125) - - 35 (146) 72 (301) -

Total element content

By wet ash digestion followed by inductively coupled plasma analysis, the total element content of Example C and commonly available comparative handpads was determined. The results are shown in Table 2. Appropriate limits are shown in Table 3.

Example C (ppm) Comparative Example 1 (ppm) Comparative Example 2 (ppm) salt 85 963 1300 potassium 5 3900 1500 calcium 2.3 mostly 23800 lithium <1 22 Not determined Goat <47 135 2300 Copper <1.4 22 206 iron 4.8 1696 830 magnesium 0.45 716 390 titanium 0.46 1461 122 sulfur 26 268 1500 sign <0.4 16 820 total 174 34199 32768

Preferred range (ppm) Good range (ppm0 Permissible value (ppm) salt 0-50 50-200 <500 potassium 0-20 20-100 <500 calcium 0-20 20-100 <500 lithium 0-20 20-50 <500 Goat 0-50 50-100 <500 Copper 0-20 20-50 <500 iron 0-20 20-50 <500 magnesium 0-20 20-50 <500 titanium 0-20 20-50 <500 sulfur 0-20 20-50 <500 sign 0-20 20-50 <500 total 0-200 200-1000 <5000

Extractable substance

Extractable and unwanted ionic materials were determined for Example B and commercially available hand pads by ionic chromatography followed by immersion in deionized water for 1 hour. Test methods are described in ASTM D4327 and USEPA 300.1, where the modification is one that causes inhibition by electrolysis, not chemical methods. The results are shown in Table 4 in ppb for selected anions and cations. Acceptable limits are shown in Table 5.

Negative ion Example B (ppb) Comparative Example 1 (ppb) Fluoride * * Chloride 7.2 11 Nitrite 0.6 2.3 Bromide * * Nitrate 6.7 7.1 Phosphate * 2.7 Sulphate 1.6 150 total 16.1 173.1 Cation Example B (ppb) Comparative Example 1 (ppb) Li 0.43 0.5 Na 96 270 ammonium 1.7 14 K 2.1 1300 Mg * 62 Ca 26 4700 total 126.23 6346.5 * Means "not detected".

range Preferred range (ppb) Good range (ppb) Threshold (ppb) Negative ion Fluoride 0-1.0 1.0-2.0 <3.0 Chloride 0-5.0 5.0-10.0 <10.0 Nitrite 0-1.0 1.0-2.0 <3.0 Bromide 0-1.0 1.0-2.0 <3.0 Nitrate 0-5.0 5.0-10.0 <10.0 Phosphate 0-1.0 1.0-2.0 <3.0 Sulphate 0-2.0 2.0-10.0 <10.0 total 0-20.0 20.0-40.0 <50.0 Cation Li 0-0.5 0.5-1.0 <5.0 Na 0-50 50-100 <150 ammonium 0-1.0 1.0-5.0 <10.0 K 0-10.0 10.0-30.0 <50.0 Mg 0-1.0 1.0-5.0 <10.0 Ca 0-10.0 10.0-30.0 <50.0 total 0-150 150-250 <300

Example A was evaluated for cuts by a dry Schiffer test conducted for 500 cycles at a load of 10 pounds. The results are shown in Table 6, where the acceptable values are at least 0.04 grams, with preferred values greater than 0.1 grams and more preferred values greater than 0.125 grams.

Example Cut (g) Comparative Example 1 0.078 Comparative Example 2 0.039 Example A 0.159

Example B was evaluated for cuts by a wet Sieffer test performed with dropping water drops for 2500 cycles on acrylic workpieces under a load of 10 pounds. Acceptable values should be greater than 2.9 grams with preferred values greater than 3.2 grams and more preferred values greater than 3.6 grams. The test results are shown in Table 7.

Example Cut (g) Comparative Example 1 3.6 Comparative Example 2 3.2 Example B 3.0

Example A was evaluated for the tendency to produce free particles by a biaxial shaking test. Represents the results are shown in Table 8, the values that are allowed here is less than 500 × 10 ⁶ particles per m ^2, the preferred range is from 100 × 10 ⁶ particles to 200 × 10 ⁶ particles per m ^2, a more preferred range is m ² per 0 to 100 × 10 ⁶ particles.

Example Particles / m ² (million) Comparative Example 1 1213 Comparative Example 2 1076 Example A 136

Comparative Example 1

Comparative Example 1 is conventional, having the trade name “SCOTCH-BRITE 7447+ General Purpose Hand Pad”, available from Minnesota Mining and Manufacturing Company, St. Paul, Minn. As-available nonwoven abrasive surface conditioning material.

Comparative Example 2

Comparative Example 2 is a commercially available non-woven abrasive general purpose cleaning pad commercially available as "Scotch-Bright # 96" from the Minnesota Mining and Manufacturing Company of St. Paul, Minn., USA.

Examples D and E

Nonwoven Support

Examples D and E were prepared to demonstrate the invention when using fibrous nonwoven supports. Table 9 shows the compositions of Examples D and E. Examples D and E were cured at an oven temperature of 350 ° F. for 2 minutes for make coating and 3 minutes for size coating.

Example Fiber Particles / 24in ² (g / m ² ) Pre-Mix 1 Particle / 24in ² (g / m ² ) Make-mix 1 particle / 24in ² (g / m ² ) Mineral A particle / 24in ² (g / m ² ) Size-Mix 1 Particle / 24in ² (g / m ² ) D 18 (75) 27 (113) 25 (104) 57 (238) 45 (188) E 18 (75) 27 (113) 35 (146) 76 (318) 53 (222)

Total element content

The total elemental content of Example D was determined by wet ash cracking followed by ion chromatography. The results are shown in ppm in Table 10. Acceptable levels of various components are shown in ppm in Table 3.

Example D (ppm) Comparative Example 1 (ppm) Comparative Example 2 (ppm) salt 87 963 1300 potassium <1 3900 1500 calcium 4 mostly 23800 lithium <1 22 (Unknown) Goat <37 135 2300 Copper <1 22 206 iron 11 1696 830 magnesium <1 716 390 titanium <1 1461 122 sulfur 11 268 1500 sign <1 16 820 total 156 34199 32768

Example E was evaluated for cuts by a dry Schiffer test procedure that conducted the test for 500 cycles under a load of 10 pounds. The results are shown in Table 11. For acceptable products, the dry cut should be at least 0.04 grams of material removed. Preferred products have at least 0.1 gram cut and more preferred products have at least 0.125 gram cut.

Example Cut (g) Comparative Example 1 0.078 Comparative Example 2 0.039 Example E 0.095

Example E was evaluated for particulate residue using a biaxial shaking test. Shows the result in Table 12, the allowable value here is a particle of less than 500 × 10 ⁶ per m ^2, the preferred value was less than 200 × 10 ⁶ particles per m ^2, more preferred value is 100 × 10 ⁶ per m ² It is below the particle.

Example Particles / m ² (million) Comparative Example 1 1213 Comparative Example 2 1076 Example E 165

Claims (24)

A flexible abrasive article comprising abrasive particles attached to the nonwoven with at least one binder and comprising less than 300 ppb of selected extractable cationic particles and less than 500 × 10 ⁶ releaseable particles per m ² . A flexible abrasive article comprising abrasive particles attached to the continuous bubble foam with one or more binders and comprising less than 300 ppb of selected extractable cationic particles and less than 500 × 10 ⁶ releaseable particles per m ² . The abrasive article of claim 1 or 2 comprising less than 250 ppb of the selected extractable cationic particles. The abrasive article of claim 1 or 2 comprising less than 150 ppb of the selected extractable cationic particles. The abrasive article of claim 1 or 2 comprising less than 200 × 10 ⁶ releasable particles per m ² . The abrasive article of claim 1 or 2 comprising less than 100 × 10 ⁶ releasable particles per m ² . The abrasive article of claim 1, wherein the abrasive article comprises a selected element content of less than about 5000 ppm. The abrasive article of claim 1, wherein the abrasive article comprises a selected element content of less than about 1000 ppm. The abrasive article of claim 1, wherein the abrasive article comprises a selected element content of less than about 200 ppm. The abrasive article of claim 1 or 2 comprising less than 50 ppb of the selected extractable anion particles. The abrasive article of claim 1 or 2 comprising less than 40 ppb of the selected extractable anion particles. The abrasive article of claim 1 or 2 comprising less than 20 ppb of the selected extractable anion particles. The abrasive article of claim 1, wherein the abrasive article comprises at least about 2.9 grams of wet cut. The abrasive article of claim 1 or 2 comprising at least about 3.2 grams of wet cut. The abrasive article of claim 1, wherein the abrasive article comprises at least about 3.6 grams of wet cut. The abrasive article of claim 1 or 2 comprising at least about 0.04 grams of dry cut. The abrasive article of claim 1, wherein the abrasive article comprises at least about 0.1 grams of dry cuts. The abrasive article of claim 1 or 2 comprising at least about 0.125 grams of dry cuts. The abrasive product of Claims 1 or 2, having an intermediate particle diameter of 10 to 100 microns. The abrasive product of Claims 1 or 2, having an average particle diameter of 30 to 60 microns. The abrasive article of claim 1, wherein the nonwoven fabric comprises organic fibers and a prebonded adhesive. 3. The abrasive article of claim 2, wherein the continuous bubble foam comprises 4-100 voids per inch. The abrasive article of claim 2, wherein the continuous foam foam comprises a reticulated foam. Providing a porous support; Coating the porous support with a make coating to form a coated support; Coating the coated support with abrasive particles to form a particle coated support; Curing the particle coated support; Coating the particle coated cured substrate with a size coating to form a size-coated support; Curing the size-coated support; Converting the size-coated cured support to form a molded abrasive article; Post-cleaning the shaped abrasive product to remove unwanted contaminants; Packaging the cleaned molded abrasive product, A method of making a flexible abrasive product containing a minimum amount of releasable physical and chemical contaminants when used on a clean surface, leaving minimal contamination on the surface and not damaging the surface.