Classifications

• • 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

Definitions

• Coated abrasives are normally made by adhesively coating the paper or cloth or other flexible backing material with, in sequence, (1) a first adhesive coat, known as the making coat; (2) a layer of abrasive grain of controlled grit size; and (3) a second adhesive coat, known as a size coat, whose function is to anchor the abrasive grains more firmly in position.
• the supersize coat a third coat, known as the supersize coat, whose function is not to act as an additional adhesive coat but to impart anti-glazing properties.
• Such supersize coat have usually been restricted to organic or inorganic compounds containing halogen or sulfur, and particularly directed to metal grinding.
• An effective anti-load or anti-glaze treatment during the manufacture of coated abrasive material is preferable to and more efficient than leaving the problem to be tackled by the user by the common practice of brushing the abrasive surface or applying some lubricant oranti-load or anti-glaze material to the abrasive surface at intervals during use.
• an object of the present invention to provide an improved coated abrasive article having improved anti-load characteristics, and in particular,
• a coated abrasive article comprising a backing material having abrasive grain adhesively secured thereto, and a'plasticized polyvinyl acetate supersize coat.
• EXAMPLE Four endless abrasive belts were made from abrasive coated roll stock material.
• the roll stock was prepared by coating paper of 130 pound weight 130 pounds per papermakers ream of 480 sheets, 24 inches X 26 inches) with a first adhesive (making) coat of hide glue, followed by a layer of grit abrasive and a second adhesive (size) coat of a phenolic (phenol-aldehyde) resin.
• the phenol-aldehyde resin was a caustic soda catalyzed resole, with a phenolzforrnaldehyde ratio of 111.56.
• the standard belts were used as controls for comparision with similar belts treated with a plasticized polyvinyl acetate super-size, applied at a weight of 2,720 g per sandpapermakers ream (480 sheets, 280 X 230 mm) in the form of a latex having a viscosity of 2 poises at 25C.
• the plasticized PVA was prepared bymixing equal amounts of a commercially available polyvinyl acetate latex having 50 percent solids and no plasticizer (sold by B?
• Plastics as Type V 700 with a commercially available plasticized polyvinyl acetate latex which is the same as the unplasticized latex, except it contains 20 parts, per parts of latex, of dibutyl phthalate plasticizer (sold by B? Plastics as Type V 701
• the plasticized PVA solution used therefore contained 50 percent polyvinyl acetate solids and 10
• the supersized belts were dried at 90C. Sanding tests were carried out on a Wadkin overhead sanding machine, sanding 200 X 125 X 50 mm' beech wood 5 blocks.
• test results q'uoted below were obtained by alternating the order of sanding with successive test pieces.
• a standard belt was'used first on one block of wood, and then a supersized belt was used.
• the order was reversed, i.e., the supersized belt was used first and then the standard belt, and so on, until each belt ground several blocks of wood.
• the pressure of the belt on the wood blocks was held constant by maintaining a load of 9 kg on the sanding machine.
• Table I gives the results of one standard versus one supersized belt, the test being carried out as described above. Each test piece was ground 10 minutes for this test.
• Tables ll and Ill give the results obtained with a second pair of belts running for 5 minutes on each block and a third pair running for 15 minutes on each block, .res ectivel TABLE II Test Stock Removal in Grams Piece Standard Belt Supersized Belt Total 301 430 TABLE III Test Stock Removal in Grams Piece Standard Belt Supersized Belt Total 282 478
• the three tables clearly illustrate the superiority of the supersized belts not only overall but also in the case of every individual test block.
• the types of backing material, abrasive and adhesives used are merely illustrative, and form no part of the invention.
• the use of a plasticizer in the polyvinyl acetate is preferred, to render the supersize coating more flexible, but the particular type of plasticizer used is not critical, and the amount of plasticizer used can be adjusted in accordance with the desired degree of flexibility.
• a coated abrasive article comprising (l) a backing material, (2) abrasive grain, and (3) adhesive means for securing the abrasive grain to the backing material, said adhesive means consisting of a first adhesive coat of hyde glue and a second adhesive coat of phenol aldehyde resin, wherein the improvement comprises a coating over the adhesive means and abrasive grain, consisting essentially of plasticized polyvinyl acetate.
• a process for making the coated abrasive article of claim 1, comprising (1) coating a backing material with a first adhesive coating consisting of hyde glue, (2) applying abrasive grain of controlled grit size over the first adhesive coating and (3) applying a second adhesive coating consisting of phenol aldehyde resin over the first adhesive coating and abrasive grain, wherein the improvement comprises applying a latex of plasticized polyvinyl acetate over the second adhesive coating, and drying the latex to provide a coating consisting essentially of plasticized polyvinyl acetate.
• coated abrasive article of claim 1 wherein said coated abrasive article does not contain halogen or sulfur.
• coated abrasive article of claim 2 wherein said coated abrasive article does not contain halogen or sulfur.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Polishing Bodies And Polishing Tools (AREA)
• Manufacture Of Macromolecular Shaped Articles (AREA)

Applications Claiming Priority (1)

Publications (1)

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ID=10225527

Family Applications (1)

Country Status (7)

Cited By (6)

Families Citing this family (5)

Citations (3)

• 1969
  • 1969-05-19 GB GB25303/69A patent/GB1243578A/en not_active Expired
• 1970
  • 1970-05-13 CH CH706770A patent/CH508457A/de not_active IP Right Cessation
  • 1970-05-15 SE SE7006710A patent/SE380463B/xx unknown
  • 1970-05-15 DE DE19702023811 patent/DE2023811A1/de active Pending
  • 1970-05-18 JP JP45041713A patent/JPS498160B1/ja active Pending
  • 1970-05-19 CA CA083081A patent/CA931767A/en not_active Expired
• 1971
  • 1971-12-16 US US00208889A patent/US3795496A/en not_active Expired - Lifetime

Patent Citations (3)

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