EP0400658A2 — Coated abrasive material, process of making and u…

Claim 1

Independent Claim 116 words

Coated abrasive material (10) having a flexible and dimensionally stable backing member (12) comprising a coated abrasive adhered to one surface of the said backing member (12), said coated abrasive comprising a radiation-cured maker coat (14) adhered to the said one surface of the backing member (12) and being characterized by its being relatively soft and flexible, a layer of abrasive grain (16) adhered to said backing member (12) by said maker coat (14) and a radiation-cured size coat (18) overlying said abrasive grains (16) and further adhering said abrasive grains (16) to the maker coat (14), said size coat (18) being characterized by its being relatively hard and brittle compared to said maker coat (14).

Claim 2

Dependent Claim 116 words

Coated abrasive material (10) having a flexible and dimensionally stable backing member (12) comprising a coated abrasive adhered to one surface of the said backing member (12), said coated abrasive comprising a radiation-cured maker coat (14) adhered to the said one surface of the backing member (12) and being characterized by its being relatively soft and flexible, a layer of abrasive grain (16) adhered to said backing member (12) by said maker coat (14) and a radiation-cured size coat (18) overlying said abrasive grains (16) and further adhering said abrasive grains (16) to the maker coat (14), said size coat (18) being characterized by its being relatively hard and brittle compared to said maker coat (14).

Claim 3

Dependent Claim 48 words

Coated abrasive material according to claim 1 wherein the maker coat (14) formulation comprises as its main ingredients a combination of radiation curable monomers having mono- and multi-functionality selected from the group consisting of N-vinyl-2 pyrrolidone, and monomers having di- and tri acrylic functionality, and an acrylated oligomer.

Claim 4

Dependent Claim 20 words

Coated abrasive material according to claim 2 wherein the acrylated oligomer is a diacrylated epoxy oligomer of the bisphenol-A type.

Claim 5

Dependent Claim 30 words

Coated abrasive material according to claim 2 or 3 wherein the monomer having diacrylic functionality is a dimer of acrylic acid and the monomer having triacrylic functionality is trimethylolpropane triacrylate.

Claim 6

Dependent Claim 50 words

Coated abrasive material according to one of the preceding claims wherein the size coat (18) formulation comprises as its main ingredients a combination of radiation curable monomers having mono- and multi-functionality selected from the group consisting of vinyl pyrrolidone and monomers having di-, and tri-acryllic functionality, and an acrylated oligomer.

Claim 7

Dependent Claim 16 words

Coated abrasive material according to claim 5 wherein the acrylated oligomer is a hexacrylated urethane oligomer.

Claim 8

Dependent Claim 18 words

Coated abrasive material according to claim 5 wherein the said acrylated oligomer comprises 10% by weight N-vinyl-2, pyrrolidone.

Claim 9

Dependent Claim 22 words

Coated abrasive material according to one of the preceding claims wherein the maker and size coat formulations each further include a filler.

Claim 10

Dependent Claim 24 words

Coated abrasive material according to claim 8 wherein the filled binder layers have relatively good light transmission compared to that of an unfilled layer.

Claim 11

Dependent Claim 23 words

Coated abrasive material according to claim 9 wherein the percent light transmittance of the filled binder layers is no less than about 85%.

Claim 12

Dependent Claim 20 words

Coated abrasive material according to one of claims 8 to 10 wherein the said filler has the hardness of silica.

Claim 13

Dependent Claim 19 words

Coated abrasive material according to one of the preceding claims wherein the abrasive grains (16) are of aluminum oxide.

Claim 14

Dependent Claim 29 words

Coated abrasive material according to claim 12 wherein the particle size of the abrasive grains ranges from about 12 to about 25 µm and preferably is about 15 µm.

Claim 15

Dependent Claim 52 words

Coated abrasive material according to one of the preceding claims, wherein the said radiation-cured maker coat (14) is characterized by a Knoop hardness of from about 18 to about 25, and the radiation-cured size coat (18) is characterized by a Knoop hardness in the range of from about 30 to about 55.

Claim 16

Dependent Claim 147 words

Coated abrasive material according to one of the preceding claims wherein the said maker coat (14) comprises the following ingredients in the amounts set forth: Ingredients Amounts Novacure 3702 7000 TMPTA 5600 V-Pyrol 3200 Sipomer BCEA 1200 Penn Color 9R-75 400 FC-171 40 KR-55 64 BYK A-510 64 Irgicure 651 640 Velveteen R 1000 the abrasive grains (16) are of aluminum oxide having a particle size in the range of from about 12 to about 25 µm; the maker coat (14) is characterized by a Knoop hardness of about 22; and the size coat (18) comprises the following ingredients in the amounts set forth: Ingredients Amount AB-514-50A 5550 TMPTA 4050 HDODA 300 V-Pyrol 3150 Sipomer BCEA 1050 Penn Color 9R-75 300 KR-55 48 FC-171 15 BYK A-510 48 Irgacure 651 480 Velveteen R 750 and such size coat is characterized by a Knoop hardness of about 32.

Claim 17

Dependent Claim 26 words

Coated abrasive material according to claim 15 wherein the abrasive grains (16) are of white aluminum oxide having an average particle size of about 15 µm.

Claim 18

Dependent Claim 23 words

Coated abrasive material according to one of the preceding claims having a backing member suitable for use as a single step fining pad.

Claim 19

Dependent Claim 154 words

Process for the manufacture of coated abrasive material, especially according to one of the preceding claims comprising the following steps: (a) providing a maker coat having as the main ingredients a combination of radiation curable monomers having mono- and multi-functionality and an acrylated oligomer; (b) applying said maker coat onto a backing member (c) applying a layer of abrasive grains to said maker coat by electrostatic means whereby to properly orient the abrasive grains for best cutting and finishing performance; (d) at least partially curing said maker coat by a suitable UV light source; (e) providing a size coat having as its main ingredients a combination of radiation curable monomers having mono- and multi- functionality and an acrylated urethane oligomer; (f) applying said size coat to said layer of abrasive grains and curing said maker and size coats whereby to provide a layer having a Knoop hardness greater than that of the maker coat.

Claim 20

Dependent Claim 28 words

Process according to claim 18 wherein the abrasive grains have relatively high electrostatic activity and such grains are applied to the maker coat by upward propulsion electrostatic means.

Claim 21

Dependent Claim 14 words

Process according to claim 18 wherein the said backing member is a polyester film.

Claim 22

Dependent Claim 70 words

Process according to one of claims 18 to 20 wherein the maker coat formulation comprises in combination monomers of N-vinyl-2 pyrrolidone, a dimer of acrylic acid, trimethylolpropane triacrylate, and an oligomer of a diacrylated epoxy oligomer of the bisphenol-A type and the size coat formulation comprises in combination monomers of N-vinyl-2 pyrrolidone, a dimer of acrylic acid, 1.6 hexanediol acrylate, trimethylolpropane tri-acrylate, and an oligomer of a hexacrylated urethane oligomer.

Claim 23

Dependent Claim 99 words

Process according to one of claims 18 to 21 wherein the weight of maker and size coats applied is in the range of from about 0.362 kg (0.8 lb.) to about 0.544 kg (1.2 lb.)/ream and in the range of from about 0.272 kg (0.6 lb.) to about 0.453 kg. (1.0 lb.)/ream respectively, and the abrasive grains are of alumina oxide having a particle size in the range of from about 12 to 25 µm and the weight of abrasive grains applied is in the range of from about 1.59 kg. (3.5 lb.) to about 2.27 kg. (5.0 lb.)/ream.

Claim 24

Dependent Claim 56 words

Process according to one of claims 18 to 22 wherein the viscosity of the maker coat is in the range of from about 400 cps (1 cps = 1 mPa.s) to about 700 cps, at 23.89°C (75°F), and dthe viscosity of the size coat is from about 100 cps to about 300 cps, at 23.89°C (75°F).

Claim 25

Dependent Claim 38 words

Use of the coated abrasive material of one of claims 1 to 17 and/or made according to one of claims 18 to 23 as a single step fining pad preferably for the treatment of optical or opthalmic surfaces.

Coated abrasive material, process of making and use of same

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