US3701703A - Method of making an abrasive foam laminate - Google Patents
Method of making an abrasive foam laminate Download PDFInfo
- Publication number
- US3701703A US3701703A US3701703DA US3701703A US 3701703 A US3701703 A US 3701703A US 3701703D A US3701703D A US 3701703DA US 3701703 A US3701703 A US 3701703A
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- Prior art keywords
- foam
- abrasive
- adhesive
- sheet
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- 239000006260 foam Substances 0.000 title description 47
- 238000004519 manufacturing process Methods 0.000 title description 11
- 239000003082 abrasive agent Substances 0.000 abstract description 14
- 238000000034 method Methods 0.000 abstract description 10
- 239000000853 adhesive Substances 0.000 description 24
- 230000001070 adhesive effect Effects 0.000 description 24
- 239000006061 abrasive grain Substances 0.000 description 17
- 239000000463 material Substances 0.000 description 17
- 239000002002 slurry Substances 0.000 description 16
- 239000011230 binding agent Substances 0.000 description 14
- 230000003014 reinforcing effect Effects 0.000 description 10
- 238000001035 drying Methods 0.000 description 9
- 239000011148 porous material Substances 0.000 description 8
- 238000005498 polishing Methods 0.000 description 7
- 239000006261 foam material Substances 0.000 description 6
- 230000008569 process Effects 0.000 description 5
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 4
- 239000004744 fabric Substances 0.000 description 4
- 238000010030 laminating Methods 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 239000002904 solvent Substances 0.000 description 4
- 239000010408 film Substances 0.000 description 3
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 3
- 229910010271 silicon carbide Inorganic materials 0.000 description 3
- 229920005830 Polyurethane Foam Polymers 0.000 description 2
- 229920001247 Reticulated foam Polymers 0.000 description 2
- 230000009471 action Effects 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 230000006835 compression Effects 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000004619 high density foam Substances 0.000 description 2
- 238000007654 immersion Methods 0.000 description 2
- 238000005470 impregnation Methods 0.000 description 2
- 238000003475 lamination Methods 0.000 description 2
- 239000004816 latex Substances 0.000 description 2
- 229920000126 latex Polymers 0.000 description 2
- 239000004620 low density foam Substances 0.000 description 2
- 229920000609 methyl cellulose Polymers 0.000 description 2
- 239000001923 methylcellulose Substances 0.000 description 2
- 235000010981 methylcellulose Nutrition 0.000 description 2
- 239000000123 paper Substances 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 239000011496 polyurethane foam Substances 0.000 description 2
- 238000005086 pumping Methods 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 239000004593 Epoxy Substances 0.000 description 1
- 239000004721 Polyphenylene oxide Substances 0.000 description 1
- 229920002143 Vulcanized fibre Polymers 0.000 description 1
- 238000005299 abrasion Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 239000007799 cork Substances 0.000 description 1
- 230000032798 delamination Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 229910003460 diamond Inorganic materials 0.000 description 1
- 239000010432 diamond Substances 0.000 description 1
- 239000012153 distilled water Substances 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 229920001971 elastomer Polymers 0.000 description 1
- 229910001651 emery Inorganic materials 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000002657 fibrous material Substances 0.000 description 1
- -1 flint Substances 0.000 description 1
- 238000005187 foaming Methods 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
- 239000002223 garnet Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000011065 in-situ storage Methods 0.000 description 1
- 238000010348 incorporation Methods 0.000 description 1
- 239000012939 laminating adhesive Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 1
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N phenol group Chemical group C1(=CC=CC=C1)O ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 description 1
- 229920000728 polyester Polymers 0.000 description 1
- 229920000570 polyether Polymers 0.000 description 1
- 229920002635 polyurethane Polymers 0.000 description 1
- 239000004814 polyurethane Substances 0.000 description 1
- 230000007420 reactivation Effects 0.000 description 1
- 230000008707 rearrangement Effects 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000009991 scouring Methods 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 239000011343 solid material Substances 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 description 1
- 229920002554 vinyl polymer Polymers 0.000 description 1
- 239000011800 void material Substances 0.000 description 1
- 238000001238 wet grinding Methods 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
- B32B5/18—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by features of a layer of foamed material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
- B24D11/00—Constructional features of flexible abrasive materials; Special features in the manufacture of such materials
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
- B24D11/00—Constructional features of flexible abrasive materials; Special features in the manufacture of such materials
- B24D11/001—Manufacture of flexible abrasive materials
- B24D11/005—Making abrasive webs
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2266/00—Composition of foam
- B32B2266/06—Open cell foam
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/249921—Web or sheet containing structurally defined element or component
- Y10T428/249953—Composite having voids in a component [e.g., porous, cellular, etc.]
- Y10T428/249986—Void-containing component contains also a solid fiber or solid particle
Definitions
- the present invention relates generally to an improved abrasive material and more specifically to a method of preparing an abrasive material designed to give both high finish and stock removal.
- a high density abrasive-containing foam product is made by impregnating a low density foam with a slurry of adhesive and abrasive, drying the same below the cure temperature of the adhesive and then laminating the dried and impregnated foam to a reinforcing backing by heat and pressure which both densifies the foam and effects the lamination using the abrasive binder adhesive to effect adhesion between the foam component and the backing component.
- the present invention constitutes an improvement in the method of forming products of the general type disclosed in the aforementioned Haywood applications and particularly relates to the formation of such products from an open celled or reticulate foam material in which the abrasive grain distribution is reasonably uniform throughout. Accordingly, it is the ob ject of this invention to provide a method for producing an abrasive material which gives superior finish and superior stock removal at one and the same time. It is a further object of the invention to provide a resilient foamcontaining material of this type which is capable of withstanding the rigorous operating conditions which have heretofore kept foam-backed abrasive products in the kitchen and out of industrial plant use to any extent.
- the present invention provides a resilient abrasive product having a high density (10 to 30 pounds per cubic foot) open cell foam uniformly impregnated with an adhesively bonded abrasive grain content and adhered to a flexible reinforcing backing member.
- the process involved in making this product includes the steps of impregnating a low density (2 to 6 pounds per cubic foot) open, interconnected cell foam material with a slurry of abrasive and binder adhesive utilizing alternate applications of compressive force and release thereof to the foam to cause the slurry to thoroughly penetrate, followed by a drying of the impregnated foam at a temperature below the curing temperature of the binder adhesive to permit retention of the porous structure of the foam, and a subsequent densification-lamination step to increase the density of the foam and to firmly adhesively bond the same to a flexible reinforcing backing.
- FIG. 1 is a cross-sectional view of the material produced by the present invention.
- FIG. 2 is an enlarged, schematic representation of a portion of the cross-section of the material of FIG. 1.
- FIG. 3 is a schematic illustration of the process used to produce the material of the present invention.
- FIG. 1 illustrates the general appearance of the improved abrasive material of the present invention.
- the material 10 comprises a flexible reinforcing and supporting member 11 which may be paper, cloth, film, fibre or any of the backing materials conventionally used for coated abrasive manufacture.
- a resilient structure 13 having a controlled density, compressibility and pore size as is more fully described below.
- Disposed on and preferably within the surface of structure 13 is a plurality of abrasive grains 14 bonded to structure 13 by an adhesive 12.
- an adhesive 12 Unseen in the scale of the drawing of FIG. 1, but shown clearly in the enlarged schematic view of FIG. 2, is the adhesion of structure 13 to backing 11 by the same adhesive 12 which serves to bind the abrasive grains to the external and internal surfaces of structure 13.
- the resilient structure 13 may be formed of any solvent-resistant, durable organic open cell or reticulated foam or foam-like material having a finished density of from to 30 pounds per cubic foot, a compression deflection value as measured by ASTM 1961 1147-61T (Test for compressibility and Recovery of Gaskets) in the 10 to 50 pounds per square inch range, a porosity of from 55% to 85% and an average pore or interstice opening diameter at the surface of from 0.006" to 0.020". Such a pore size amounts to a count of from about 80 to 150 openings per linear inch.
- the finished density ranges from 14 to 16 pounds per cubic foot and the pore size is the equivalent of 100 plus or :minus 10 openings per linear inch. While the thickness of the finished resilient structure may vary substantially dependent upon the use of the resultant abrasive product, it, is preferably A" or less in thickness with the optimum being about 3%" thickness.
- the finished density of the foam structure is required to be in the range of 10 to pounds per cubic foot with definite porosity requirements.
- open cell or reticulated foams of this high density are not readily available commercially.most of the commercial foams of this type ranging from 2 to 6 pounds per cubic foot which are far too soft and compressible for our purposes.
- the pore size of such high density foams is far too small to permit their use in the production of the desired product of this invention.
- Typical open, interconnected cell polyurethane foams are well known as, for example, described in US. Pat. No. 2,961,710. Accordingly, the present invention is concerned in part with the process whereby the desired final or finished high density foam structure is obtained from a starting material of much lower density as is described in detail below.
- the flexible backing member may be any of the conventional, readily available flexible backings known to the coated abrasive art. While conventional coated abrasive cloth backings are preferred, due to the ease with which they may be joined in the fabrication of belts, etc., it is possible to use many types of filamentary or fibrous materials such as papers, vulcanized fibres, films, foils, thin metal backings and the like as the end application use may dictate.
- the resilient structure is bonded to the backing member through reactivation of the abrasive binder adhesive as described below.
- the binder adhesive is solvent-resistant in order to prevent delamination when the product is used in wet grinding operations.
- Adhesion of the foam to the backing must be sufiicient to withstand the shock, shear stress and abrasion encountered during use and should generally be in excess of 4.0 pounds per inch as measured by ASTM (1964) D-1876, T-Peel Test, or at least in excess of the value at which the foam cohesively fails when the foam-to-backing adhesion is measured by such test.
- the abrasive grain is preferably on the fine side ranging from grit 220 down to grit 400 or finer.
- the type of abrasive grain does not appear critical and any of the abrasive materials such as silicon carbide, aluminum oxide, garnet, flint, diamond, emery and the like or mixtures thereof conventionally used in the coated abrasive art may be used in the present product as desired.
- the grit binder for use on this polishing and buffing material must be at least semi-flexible when cured and dried to its final stage.
- the adhesive should not be highly cohesive in the sense that it forms a film over the pores of the resilient structure. These pores must be left substantially open in the finished product.
- the grit binder is solvent resistant and the use of drying oil-modified phenolic,
- the adhesive grit binder is not applied in a separate layer as with conventional coated abrasives but is used to form a slurry with the abrasive grain and the mixture of grain and adhesive is applied by the process described below.
- the starting point of the production of the abrasive article of the present invention is the provision of a sheet 30 (preferably in continuous form) of a low density, resilient, highly porous, open celled or reticulate foam material.
- foams may have an initial density of from 2 to 6 pounds per cubic foot and an initial porosity of or more- (by 80% porosity is meant that 80% of the volume of the specimen is void and only 20% is solid material.
- the porosity is determined by comparing the apparent volume of a specimen, i.e., its weight in air divided by its measured geometric volume, with its actual volume, i.e., that volume actually occupied by the solid parts of the structure).
- the material is a polyester or polyether type polyurethane foam.
- Other foams such as open cell rubber or vinyl foams can beused if desired.
- the low density foam sheet 30 is passed into impregnating contact with a slurry 33 formed of adhesive 31 and abrasive grain 32, e. g., by immersion, as shown at 34. While contact is maintained between the foam sheet 30 and slurry 33, the foam sheet '30 is repeatedly pressed or squeezed as by rollers 35-36 and 37-38 with alternate release of pressure between squeezings as shown schematically in the drawing. This creates a pumping action whereby the slurry 33 is uniformly dispersed throughout the open cell structure of foam sheet 30.
- the wet foam sheet 30 now containing a fairly uniform coating of adhesive 31 and abrasive grain 32 on all of its exterior and interior surfaces (as is more clearly seen in FIG. 2) passes to a drying zone 39.
- the sheet 30 has excess slurry wiped from its external surfaces by wipers 4.0-41 as it passes to zone 39.
- Zone 39 must be maintained at a temperature below the cure temperature of the binder adhesive 31 and the drying cycle should be sufficiently long to permit most of the solvent to escape from the binder adhesive and for the adhesive to dry to a non-tacky state.
- zone 39 the dried and impregnated sheet 30 now moves to a laminating zone 42 wherein it is mated with a supporting backing 43 of the type previously described.
- Rolls 44-45 are heated and generate the requisite curing temperature in sheet 30 to cure the adhesive binder 31 to an insoluble state.
- the spacing or gap-setting of rolls 44-45 is such as to compress sheet 30 to the desired final thickness, e.g., ,4
- heated platens 46-47 may be provided, if necessary, to hold the temperature and pressure of sheet 30 at the required cure and laminating level until completion.
- the resiliency of the finished product is at least 8% and preferably 9% or more as measured by ASTM D-1564-R, Resilience (Ball Rebound) Test.
- the deposited grain weight from slurry 33 is preferably about 6 pounds per sandpaper ream when using 400 grit silicon carbide, although grain weights as low as 2-3 pounds per sandpaper ream or as high as 9-10 pounds per sandpaper ream may be used if desired.
- the foam material is alternately subjected to squeezing and release during its passage through the slurry (4 cycles) with a pick up of about 1,000% of its initial weight.
- the wet foam then passes through a pair of wipers which remove excess surface slurry and then is passed into a drying zone maintained at room temperature for a period of 18 hours. Upon removal from the zone the foam will be non-tacky to the touch and weighs about 600% of the initial foam weight. The height or thickness of the foam was only slightly reduced.
- the dried and impregnated foam material was then combined with a standard Waterproof coated abrasive cloth backing material using heated rolls set to a 0.080 gap in conjunction with spaced heated platens (same gap setting).
- the temperature of the rolls and platens was held at 315 F. and the heating time of the laminate was 10 minutes.
- the product was air cooled to room temperature and wound into a jumbo storage roll. A number of discs were then cut from this material and used to polish the surface of acrylic test pieces. The resulting finish was excellent and showed none of the scratch pattern normal with a coated abrasive polishing belt.
- the present invention permits the relatively uniform incorporation of abrasive grain within a foam structure of ultimate high density to provide a resilient, porous media which is supported by a reinforcing backing.
- the product density and dimensions are controlled by the application of pressure after impregnation and drying. Pressure without permitting the drying would cause the pores to be closed and would not produce the desired product.
- no separate laminating adhesive is required to bond the impregnated foam to the reinforcing support backing but the grit binder serves a dual purpose in this regard.
- a method for producing an abrasive material which comprises:
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Abstract
THE PRESENT INVENTION RELATES GENERALLY TO AN IMPROVED ABRASIVE MATERIAL AND MORE SPECIFICALLY TO A METHOD OF PREPARING AN ABRASIVE MATERIAL DESIGNED TO GIVE BOTH HIGH FINISH AND STOCK REMOVAL.
Description
w. F. ZIMMER. JR.. FI'AL METHOD OF MAKING AN ABRASIVE FOAM LAMINATE I Oct. 31', 1972 Original Filed Dec. 4, 1969 WILLIAM PWfiEim' VEY 1.. CH
fs/nfi AWORNEY United States Patent O 3,701,703 METHOD OF MAKING AN ABRASIVE FOAM LAMINATE William F. Zimmer, Jr., Paxton, Mass., and Harvey L. Chew, Latham, N.Y., assignors to Norton Company, Troy, NY.
Original application Dec. 4, 1969, Ser. No. 882,110, now Patent No. 3,653,859. Divided and this application July 12, 1971, Ser. No. 161,570
Int. Cl. B32b 31/12, /18; B24d 11/00 US. Cl. 156278 3 Claims ABSTRACT OF THE DISCLOSURE The present invention relates generally to an improved abrasive material and more specifically to a method of preparing an abrasive material designed to give both high finish and stock removal.
A high density abrasive-containing foam product is made by impregnating a low density foam with a slurry of adhesive and abrasive, drying the same below the cure temperature of the adhesive and then laminating the dried and impregnated foam to a reinforcing backing by heat and pressure which both densifies the foam and effects the lamination using the abrasive binder adhesive to effect adhesion between the foam component and the backing component.
CROSS-REFERENCE TO RELATED APPLICATION This application is a division of my copending application Ser. No. 882,110 filed Dec. 4, 1969 for Abrasive Foam Laminate, now US. Pat. No. 3,653,859.
BACKGROUND OF THE INVENTION (1) Field This invention deals with the production of an abrasive material wherein a flexible backing is provided to support a plurality of abrasive grains adhesively bonded therein. It further relates to the fine abrasive end of such field wherein finish of the workpiece abraded constitutes one of the important criteria for the performance of the abrasive material. The terms bufling and polishing, while generally synonymous in common usage have definite and different meanings in the abrasive art. Buffing means the rearrangement of material on the surface of a workpiece, usually by friction, to produce a high finish. In contrast, polishing means the removal of material from a surface to correct minor surface imperfections. It is well accepted in the art that as the requirement for high finish goes up the ability to remove stock comes down. Therefore, the art has consistently used one type of relatively aggressive abrasive material for polishing and the desired stock removal and a different type of non-abrasive or only slightly abrasive material for bufling to a high finish.
(2) Prior art Abrasive products made on resilient backings of various types have been proposed for many years. Most of these seem to have been the outgrowth of the use of sponge material for cleaning purposes and generally have fallen into three categories: (1) a foam or sponge having a coating of abrasive particles on the exterior thereof; (2) a sheet of coated abrasive laminated to a sponge or foam backing; and (3) abrasive grain incorporated in the foamable material prior to foaming with the resultant in situ production of a foam containing abrasive grain substantially uniformly distributed throughout. These products have never gained good commercial acceptance except for some minor successes as kitchen scouring aids. Industrially, the best performing product for polishing purposes has not been a sponge or foam-backed material but rather one in which a layer of cork particles provided the resilient support required to obtain a reasonably good finish while the abrasive grain coated on the surface thereof gave a reasonable amount of stock removal. None of these prior art products have given satisfactory combined finish levels and stock removal rates to satisfy the needs of industry. Laminates of particulate bonded foam material and associated flexible reinforcing backing are disclosed and claimed in the copending applications of George L. Haywood, Ser. No. 632,978, filed Apr. 24, 1967, now abandoned, and Ser. No. 638,042, filed May 12, 1967, now US. Pat. No. 3,607,159. The present invention constitutes an improvement in the method of forming products of the general type disclosed in the aforementioned Haywood applications and particularly relates to the formation of such products from an open celled or reticulate foam material in which the abrasive grain distribution is reasonably uniform throughout. Accordingly, it is the ob ject of this invention to provide a method for producing an abrasive material which gives superior finish and superior stock removal at one and the same time. It is a further object of the invention to provide a resilient foamcontaining material of this type which is capable of withstanding the rigorous operating conditions which have heretofore kept foam-backed abrasive products in the kitchen and out of industrial plant use to any extent.
SUMMARY In general, the present invention provides a resilient abrasive product having a high density (10 to 30 pounds per cubic foot) open cell foam uniformly impregnated with an adhesively bonded abrasive grain content and adhered to a flexible reinforcing backing member. The process involved in making this product includes the steps of impregnating a low density (2 to 6 pounds per cubic foot) open, interconnected cell foam material with a slurry of abrasive and binder adhesive utilizing alternate applications of compressive force and release thereof to the foam to cause the slurry to thoroughly penetrate, followed by a drying of the impregnated foam at a temperature below the curing temperature of the binder adhesive to permit retention of the porous structure of the foam, and a subsequent densification-lamination step to increase the density of the foam and to firmly adhesively bond the same to a flexible reinforcing backing.
DRAWINGS FIG. 1 is a cross-sectional view of the material produced by the present invention.
FIG. 2 is an enlarged, schematic representation of a portion of the cross-section of the material of FIG. 1.
FIG. 3 is a schematic illustration of the process used to produce the material of the present invention.
DESCRIPTION OF PREFERRED EMBODIMENTS More specifically, and referring now to the drawings, FIG. 1 illustrates the general appearance of the improved abrasive material of the present invention. The material 10 comprises a flexible reinforcing and supporting member 11 which may be paper, cloth, film, fibre or any of the backing materials conventionally used for coated abrasive manufacture. Superposed on and sharing an interface with said backing 11 to which it is adhered is a resilient structure 13 having a controlled density, compressibility and pore size as is more fully described below. Disposed on and preferably within the surface of structure 13 is a plurality of abrasive grains 14 bonded to structure 13 by an adhesive 12. Unseen in the scale of the drawing of FIG. 1, but shown clearly in the enlarged schematic view of FIG. 2, is the adhesion of structure 13 to backing 11 by the same adhesive 12 which serves to bind the abrasive grains to the external and internal surfaces of structure 13.
The resilient structure 13 may be formed of any solvent-resistant, durable organic open cell or reticulated foam or foam-like material having a finished density of from to 30 pounds per cubic foot, a compression deflection value as measured by ASTM 1961 1147-61T (Test for compressibility and Recovery of Gaskets) in the 10 to 50 pounds per square inch range, a porosity of from 55% to 85% and an average pore or interstice opening diameter at the surface of from 0.006" to 0.020". Such a pore size amounts to a count of from about 80 to 150 openings per linear inch. In the preferred embodiment the finished density ranges from 14 to 16 pounds per cubic foot and the pore size is the equivalent of 100 plus or :minus 10 openings per linear inch. While the thickness of the finished resilient structure may vary substantially dependent upon the use of the resultant abrasive product, it, is preferably A" or less in thickness with the optimum being about 3%" thickness.
As indicated above, the finished density of the foam structure is required to be in the range of 10 to pounds per cubic foot with definite porosity requirements. Generally, it can be stated that open cell or reticulated foams of this high density are not readily available commercially.most of the commercial foams of this type ranging from 2 to 6 pounds per cubic foot which are far too soft and compressible for our purposes. Where available on an experimental basis, it has been found that the pore size of such high density foams is far too small to permit their use in the production of the desired product of this invention. Typical open, interconnected cell polyurethane foams are well known as, for example, described in US. Pat. No. 2,961,710. Accordingly, the present invention is concerned in part with the process whereby the desired final or finished high density foam structure is obtained from a starting material of much lower density as is described in detail below.
As previously indicated, the flexible backing member may be any of the conventional, readily available flexible backings known to the coated abrasive art. While conventional coated abrasive cloth backings are preferred, due to the ease with which they may be joined in the fabrication of belts, etc., it is possible to use many types of filamentary or fibrous materials such as papers, vulcanized fibres, films, foils, thin metal backings and the like as the end application use may dictate.
The resilient structure is bonded to the backing member through reactivation of the abrasive binder adhesive as described below. Preferably, the binder adhesive is solvent-resistant in order to prevent delamination when the product is used in wet grinding operations. Adhesion of the foam to the backing must be sufiicient to withstand the shock, shear stress and abrasion encountered during use and should generally be in excess of 4.0 pounds per inch as measured by ASTM (1964) D-1876, T-Peel Test, or at least in excess of the value at which the foam cohesively fails when the foam-to-backing adhesion is measured by such test.
Since the primary usage of this material is in a combined polishing and buffing type operation, the abrasive grain ispreferably on the fine side ranging from grit 220 down to grit 400 or finer. The type of abrasive grain does not appear critical and any of the abrasive materials such as silicon carbide, aluminum oxide, garnet, flint, diamond, emery and the like or mixtures thereof conventionally used in the coated abrasive art may be used in the present product as desired.
In contrast to conventional coated abrasives where an extremely hard, rigid binder is desired, the grit binder for use on this polishing and buffing material must be at least semi-flexible when cured and dried to its final stage. The adhesive should not be highly cohesive in the sense that it forms a film over the pores of the resilient structure. These pores must be left substantially open in the finished product. Generally, the grit binder is solvent resistant and the use of drying oil-modified phenolic,
acrylic or epoxy resinsv is preferred. The adhesive grit binder is not applied in a separate layer as with conventional coated abrasives but is used to form a slurry with the abrasive grain and the mixture of grain and adhesive is applied by the process described below.
Referring now to FIG. 3 of the drawings, the starting point of the production of the abrasive article of the present invention is the provision of a sheet 30 (preferably in continuous form) of a low density, resilient, highly porous, open celled or reticulate foam material. Such foams may have an initial density of from 2 to 6 pounds per cubic foot and an initial porosity of or more- (by 80% porosity is meant that 80% of the volume of the specimen is void and only 20% is solid material. The porosity is determined by comparing the apparent volume of a specimen, i.e., its weight in air divided by its measured geometric volume, with its actual volume, i.e., that volume actually occupied by the solid parts of the structure). Preferably, the material is a polyester or polyether type polyurethane foam. Other foams such as open cell rubber or vinyl foams can beused if desired. The low density foam sheet 30 is passed into impregnating contact with a slurry 33 formed of adhesive 31 and abrasive grain 32, e. g., by immersion, as shown at 34. While contact is maintained between the foam sheet 30 and slurry 33, the foam sheet '30 is repeatedly pressed or squeezed as by rollers 35-36 and 37-38 with alternate release of pressure between squeezings as shown schematically in the drawing. This creates a pumping action whereby the slurry 33 is uniformly dispersed throughout the open cell structure of foam sheet 30. With proper control of viscosity, simple immersion in the slurry may be adequate in some instances but the alternate application and release of pressure is a preferred step. From the impregnating zone 34, the wet foam sheet 30 now containing a fairly uniform coating of adhesive 31 and abrasive grain 32 on all of its exterior and interior surfaces (as is more clearly seen in FIG. 2) passes to a drying zone 39. Preferably, the sheet 30 has excess slurry wiped from its external surfaces by wipers 4.0-41 as it passes to zone 39. Zone 39 must be maintained at a temperature below the cure temperature of the binder adhesive 31 and the drying cycle should be sufficiently long to permit most of the solvent to escape from the binder adhesive and for the adhesive to dry to a non-tacky state. These conditions will obviously vary depending upon the choice of binder adhesive but it has been found that provision of a dwell time in zone 39 of 24 hours at ambient room temperature is generally adequate. From zone 39, the dried and impregnated sheet 30 now moves to a laminating zone 42 wherein it is mated with a supporting backing 43 of the type previously described. Rolls 44-45 are heated and generate the requisite curing temperature in sheet 30 to cure the adhesive binder 31 to an insoluble state. The spacing or gap-setting of rolls 44-45 is such as to compress sheet 30 to the desired final thickness, e.g., ,4 This combination of heat and pressure causes the adhesive 31, which is on the interface surface of member 30 next to backing 43, to adhere to backing 43 and to effectively laminate sheet 30 to backing 43. As shown, heated platens 46-47 may be provided, if necessary, to hold the temperature and pressure of sheet 30 at the required cure and laminating level until completion. 1
The resiliency of the finished product is at least 8% and preferably 9% or more as measured by ASTM D-1564-R, Resilience (Ball Rebound) Test. The deposited grain weight from slurry 33 is preferably about 6 pounds per sandpaper ream when using 400 grit silicon carbide, although grain weights as low as 2-3 pounds per sandpaper ream or as high as 9-10 pounds per sandpaper ream may be used if desired.
Percent by weight Acrylic latex (49% total solids) 30.3
Methyl cellulose (4% aqueous) 6.0 400 grit silicon carbide abrasive grain 45.5 Distilled water 18.2
The foam material is alternately subjected to squeezing and release during its passage through the slurry (4 cycles) with a pick up of about 1,000% of its initial weight. The wet foam then passes through a pair of wipers which remove excess surface slurry and then is passed into a drying zone maintained at room temperature for a period of 18 hours. Upon removal from the zone the foam will be non-tacky to the touch and weighs about 600% of the initial foam weight. The height or thickness of the foam was only slightly reduced. The dried and impregnated foam material was then combined with a standard Waterproof coated abrasive cloth backing material using heated rolls set to a 0.080 gap in conjunction with spaced heated platens (same gap setting). The temperature of the rolls and platens was held at 315 F. and the heating time of the laminate was 10 minutes. Upon removal from the laminating zone the product was air cooled to room temperature and wound into a jumbo storage roll. A number of discs were then cut from this material and used to polish the surface of acrylic test pieces. The resulting finish was excellent and showed none of the scratch pattern normal with a coated abrasive polishing belt.
A similar run was made in batch fashion using the same slurry as previously mentioned (made by adding the methyl cellulose to the acrylic latex with stirring to give a uniform blend followed by addition of the grain with rapid stirring and finally the addition of the water after the grain had been completely dispersed to give a uniform slurry). In this instance, a hard sheet of foam 6 /2" x 4" x was used. The foam was 2 pounds per cubic inch polyurethane open cell foam. By hand squeezing, the foam was impregnated with the slurry, wiped off and allowed to dry for 24 hours at room temperature. The dried and impregnated foam was then combined with a standard waterproof coated abrasive cloth backing in a heated press. The pressure was about 100 p.s.i. and the laminate was compressed to a total thickness of 0.08". The temperature of the press was 315 F. and the dwell time slightly over 10 minutes. The finished product was used as a hard sheet to polish oak floor tiles and was found to be superior to standard products in the finish produced.
The present invention permits the relatively uniform incorporation of abrasive grain within a foam structure of ultimate high density to provide a resilient, porous media which is supported by a reinforcing backing. The product density and dimensions are controlled by the application of pressure after impregnation and drying. Pressure without permitting the drying would cause the pores to be closed and would not produce the desired product. By virtue of this process, no separate laminating adhesive is required to bond the impregnated foam to the reinforcing support backing but the grit binder serves a dual purpose in this regard.
What is claimed is:
1. A method for producing an abrasive material which comprises:
(a) impregnating a pre-formed, low density, open cell foam sheet with a slurry of heat-curable adhesive and abrasive;
(b) drying the impregnated foam sheet to a tack-free state at a temperature below the curing temperature of the adhesive;
(c) applying a flexible reinforcing sheet to one surface of said dried impregnated foam sheet;
(d) compressing said foam sheet against said reinforcing sheet to increase the density of said foam sheet; and
(e) while maintaining said compression, applying sufficient heat to said foam sheet to cure said adhesive and to bond said reinforcing sheet to the surface of said foam sheet.
2. A method as in claim 1 wherein said impregnation comprises the steps of:
(a) immersing the open cell foam sheet in a bath of liquid adhesive and admixed abrasive grain; and
(b) alternately applying and releasing pressure on said sheet while so immersed so as to create a pumping action drawing the adhesive-abrasive grain mixture into the interstices of said open cell sheet.
3. A method as in claim 1 wherein the density of the foam sheet is increased to within the range of from about 10 to about 30 pounds per cubic foot.
References Cited UNITED STATES PATENTS 2,327,199 8/1943 Loefiler 51-293 2,885,276 5/1959 Upton 51298 2,958,593 11/1960 Hoover et al 51-295 3,020,139 2/ 1962 Camp et al. 51295 3,112,219 11/1963 Politzer et a1 11798 3,238,056 3/1966 Pall et a1. 11798 3,252,775 5/ 1966 Tocci-Guilbert 51-296 3,607,159 9/ 1971 Haywood 51-295 ROBERT F. B-U-RNETT, Primary Examiner R. A. DAWSON, Assistant Examiner U.S.Cl. X.R.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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US88211069A | 1969-12-04 | 1969-12-04 | |
US16157071A | 1971-07-12 | 1971-07-12 |
Publications (1)
Publication Number | Publication Date |
---|---|
US3701703A true US3701703A (en) | 1972-10-31 |
Family
ID=26857942
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US3701703D Expired - Lifetime US3701703A (en) | 1969-12-04 | 1971-07-12 | Method of making an abrasive foam laminate |
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US (1) | US3701703A (en) |
Cited By (21)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3918220A (en) * | 1973-08-09 | 1975-11-11 | Ryton Mach Tools Coventry Ltd | Method of grinding a surface of a workpiece and a tool for carrying out the method |
FR2372697A1 (en) * | 1976-12-06 | 1978-06-30 | Composite Tech Corp | LAMINATE AND ITS MANUFACTURING PROCESS |
EP0163521A2 (en) * | 1984-06-01 | 1985-12-04 | Ferro Corporation | Fixed ophthalmic lens polishing pad |
EP0304645A2 (en) * | 1987-08-25 | 1989-03-01 | Rodel, Inc. | Inverted cell pad material for grinding, lapping, shaping and polishing |
US4966609A (en) * | 1989-04-07 | 1990-10-30 | Uniroyal Plastics Co., Inc. | Conformable abrasive article |
US5565010A (en) * | 1993-09-08 | 1996-10-15 | Price; Daryl L. | Method of manufacturing foam rubber plastic cleaning apparatus |
US5849051A (en) * | 1997-11-12 | 1998-12-15 | Minnesota Mining And Manufacturing Company | Abrasive foam article and method of making same |
US5863305A (en) * | 1996-05-03 | 1999-01-26 | Minnesota Mining And Manufacturing Company | Method and apparatus for manufacturing abrasive articles |
US6007590A (en) * | 1996-05-03 | 1999-12-28 | 3M Innovative Properties Company | Method of making a foraminous abrasive article |
US6017831A (en) * | 1996-05-03 | 2000-01-25 | 3M Innovative Properties Company | Nonwoven abrasive articles |
US20030088249A1 (en) * | 2001-11-03 | 2003-05-08 | Sebastian Furderer | Device for straightening and stabilizing the vertebral column |
EP1595647A2 (en) * | 2004-05-14 | 2005-11-16 | Peter Jöst | Grinding tool |
US20080148522A1 (en) * | 2005-03-01 | 2008-06-26 | Max-Tech Products, Inc. | Glide Device and Article of Furniture Incorporating the Same |
US20080188168A1 (en) * | 2007-02-05 | 2008-08-07 | San Fang Chemical Industry Co., Ltd. | Polishing material having polishing particles and method for making the same |
US7666205B2 (en) | 2001-04-19 | 2010-02-23 | Synthes Usa, Llc | Inflatable device and method for reducing fractures in bone and in treating the spine |
US8518115B2 (en) | 2007-11-16 | 2013-08-27 | DePuy Synthes Products, LLC | Porous containment device and associated method for stabilization of vertebral compression fractures |
US20140295741A1 (en) * | 2011-01-17 | 2014-10-02 | 3M Innovative Properties Company | Polyurethane foam article |
US8870985B2 (en) | 2010-12-30 | 2014-10-28 | Saint-Gobain Abrasives, Inc. | Abrasive particle and method of forming same |
US8911497B2 (en) | 2009-04-09 | 2014-12-16 | DePuy Synthes Products, LLC | Minimally invasive spine augmentation and stabilization system and method |
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- 1971-07-12 US US3701703D patent/US3701703A/en not_active Expired - Lifetime
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US3918220A (en) * | 1973-08-09 | 1975-11-11 | Ryton Mach Tools Coventry Ltd | Method of grinding a surface of a workpiece and a tool for carrying out the method |
FR2372697A1 (en) * | 1976-12-06 | 1978-06-30 | Composite Tech Corp | LAMINATE AND ITS MANUFACTURING PROCESS |
EP0163521A2 (en) * | 1984-06-01 | 1985-12-04 | Ferro Corporation | Fixed ophthalmic lens polishing pad |
EP0163521A3 (en) * | 1984-06-01 | 1988-08-10 | Ferro Corporation | Fixed ophthalmic lens polishing pad |
EP0304645A2 (en) * | 1987-08-25 | 1989-03-01 | Rodel, Inc. | Inverted cell pad material for grinding, lapping, shaping and polishing |
EP0304645A3 (en) * | 1987-08-25 | 1990-01-24 | Rodel, Inc. | Inverted cell pad material for grinding, lapping, shaping and polishing |
US4966609A (en) * | 1989-04-07 | 1990-10-30 | Uniroyal Plastics Co., Inc. | Conformable abrasive article |
US5565010A (en) * | 1993-09-08 | 1996-10-15 | Price; Daryl L. | Method of manufacturing foam rubber plastic cleaning apparatus |
US5863305A (en) * | 1996-05-03 | 1999-01-26 | Minnesota Mining And Manufacturing Company | Method and apparatus for manufacturing abrasive articles |
US6007590A (en) * | 1996-05-03 | 1999-12-28 | 3M Innovative Properties Company | Method of making a foraminous abrasive article |
US6017831A (en) * | 1996-05-03 | 2000-01-25 | 3M Innovative Properties Company | Nonwoven abrasive articles |
US5849051A (en) * | 1997-11-12 | 1998-12-15 | Minnesota Mining And Manufacturing Company | Abrasive foam article and method of making same |
US7666205B2 (en) | 2001-04-19 | 2010-02-23 | Synthes Usa, Llc | Inflatable device and method for reducing fractures in bone and in treating the spine |
US20130310877A1 (en) * | 2001-11-03 | 2013-11-21 | DePuy Synthes Products, LLC | Device for straightening and stabilizing the vertebral column |
US11051862B2 (en) | 2001-11-03 | 2021-07-06 | DePuy Synthes Products, Inc. | Device for straightening and stabilizing the vertebral column |
US20030088249A1 (en) * | 2001-11-03 | 2003-05-08 | Sebastian Furderer | Device for straightening and stabilizing the vertebral column |
US10357291B2 (en) | 2001-11-03 | 2019-07-23 | DePuy Synthes Products, Inc. | Device for straightening and stabilizing the vertebral column |
US9861401B2 (en) | 2001-11-03 | 2018-01-09 | DePuy Synthes Products, Inc. | Device for straightening and stabilizing the vertebral column |
US8491591B2 (en) | 2001-11-03 | 2013-07-23 | DePuy Synthes Products, LLC | Device for straightening and stabilizing the vertebral column |
US9295502B2 (en) | 2001-11-03 | 2016-03-29 | DePuy Synthes Products, Inc. | Device for straightening and stabilizing the vertebral column |
US20050255802A1 (en) * | 2004-05-14 | 2005-11-17 | Peter Jost | Grinding member |
EP1595647A3 (en) * | 2004-05-14 | 2006-01-25 | Peter Jöst | Grinding tool |
EP1595647A2 (en) * | 2004-05-14 | 2005-11-16 | Peter Jöst | Grinding tool |
US20080148522A1 (en) * | 2005-03-01 | 2008-06-26 | Max-Tech Products, Inc. | Glide Device and Article of Furniture Incorporating the Same |
US7824249B2 (en) * | 2007-02-05 | 2010-11-02 | San Fang Chemical Industry Co., Ltd. | Polishing material having polishing particles and method for making the same |
US8485869B2 (en) | 2007-02-05 | 2013-07-16 | San Fang Chemical Industry Co., Ltd. | Polishing material having polishing particles and method for making the same |
US20110011007A1 (en) * | 2007-02-05 | 2011-01-20 | San Fang Chemical Industry Co., Ltd. | Polishing material having polishing particles and method for making the same |
US20080188168A1 (en) * | 2007-02-05 | 2008-08-07 | San Fang Chemical Industry Co., Ltd. | Polishing material having polishing particles and method for making the same |
US9114019B2 (en) | 2007-11-16 | 2015-08-25 | DePuy Synthes Products, Inc. | Porous containment device and associated method for stabilization of vertebral compression fractures |
US8518115B2 (en) | 2007-11-16 | 2013-08-27 | DePuy Synthes Products, LLC | Porous containment device and associated method for stabilization of vertebral compression fractures |
US8911497B2 (en) | 2009-04-09 | 2014-12-16 | DePuy Synthes Products, LLC | Minimally invasive spine augmentation and stabilization system and method |
US8870985B2 (en) | 2010-12-30 | 2014-10-28 | Saint-Gobain Abrasives, Inc. | Abrasive particle and method of forming same |
US20140295741A1 (en) * | 2011-01-17 | 2014-10-02 | 3M Innovative Properties Company | Polyurethane foam article |
US9133296B2 (en) * | 2011-01-17 | 2015-09-15 | 3M Innovative Properties Company | Polyurethane foam article |
US9539041B2 (en) | 2013-09-12 | 2017-01-10 | DePuy Synthes Products, Inc. | Minimally invasive biomaterial injection system |
US10660762B2 (en) | 2013-09-12 | 2020-05-26 | DePuy Synthes Product, Inc. | Minimally invasive biomaterial injection system |
CN104723228A (en) * | 2015-04-10 | 2015-06-24 | 淄博理研泰山涂附磨具有限公司 | Foam coating grinding tool and preparing method thereof |
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