Patent GB-813372-A (GB)
Title: Improvements in or relating to the manufacture of abrasive articles
IPC: B24D3/28
Filed: 1954-07-19
Abstract: An abrasive article, e.g. a grinding wheel, comprises abrasive grains bonded by a polyphosphonitrilic chloride which has been further polymerized in situ.  The initial mix preferably comprises a low molecular weight polyphosphonitrilic chloride, or a polyphosphonitrilic chloride modified by reaction with a polyhydroxy aromatic compound, e.g. resorcinol, hydroquinone, or a partial ester with boric acid, with an inorganic phosphoric acid or a polyfunctional chlorine derivative thereof, or with phosphorus trichloride.  The abrasive grains may comprise diamond dust, carborundum, boron carbide, or spinel.  In examples, the mixes comprise (1) an oily polyphosphonitrilic chloride and carborundum; (2) carborundum or other abrasive grains, an oily polyphosphonitrilic chloride, hexamethylenetetramine, and a resin bonding agent prepared by heating together hydroquinone, resorcinol and boric acid; (3) abrasive grains, a modified polyphosphonitrilic chloride formed by mixing an oily polyphosphonitrilic chloride with an equal weight of hydroquinone and heating the mixture at 180 DEG  to 190 DEG  C. for 50 minutes; (4) and (5) the same ingredients as in (2) but of different proportions; (6) a modified polyphosphonitrile as in (3) and silicon carbide grains; (7) only polyphosphonitrilic chloride added to the mix of Example 6; and (8) diamond dust and the modified polyphosphonitrilic chloride of Example 3.  In all the Examples the further polymerization is effected by heating the mixture in a mould. Specifications 788,785, [Group VII], 801,929, [Group V], 807,851 and 812,126 are referred to.ALSO:An abrasive article, e.g. a grinding wheel comprises abrasive grains bonded by a polyphosphonitrilic chloride which has been further polymerized in situ.  The initial mix preferably comprises a low molecular weight polyphosphonitrilic chloride, or a polyphosphonitrilic chloride modified by reaction with a polyhydroxy aromatic compound, e.g. resorcinol, hydroquinone, or a partial ester with boric acid, with an inorganic phosphoric acid or a polyfunctional chlorine derivative thereof, or with phosphorus trichloride.  The abrasive grains may comprise diamond dust, caborundum, boron carbide, or spinel.  In Examples the mixes comprise (1) an oily polyphosphonitrilic chloride and carborundum (2) carborundum or other abrasive grains, an oily polyphosphonitrilic chloride, hexamethylene-tetramine, and a resin bonding agent prepared by heating together hydroquinone, resorcinol and boric acid, (3) abrasive grains, a modified polyphosphonitrilic chloride formed by mixing an oily polyphosphonitrilic chloride with an equal weight of hydroquinone and heating the mixture at 180 DEG  to 190 DEG C. for 50 minutes, (4) and (5) the same ingredients as in (2) but of different proportions (6) a modified polyphosphonitrile as in (3) and silicon carbide grains, (7) oily polyphosphonitrilic chloride added to the mix of Example 6, and (8) diamond dust and the modified polyphosphonitrile chloride of Example 3.  In all the Examples the further polymerization is effected by heating the mixture in a mould. Specifications 788,785 [Group VII], 801,929, 807,851 and 812,126 [both in Group IV(a)] are referred to.