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Патент USA US2135626

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Patented Nov. s, 1938
2,135,626 .
Norman P. Robie, Niagara Falls, N. Y., ammo:
to The Carborundum Company, Niagara Falls,
, N. Y” a corporation oi’ Delaware
No Drawing. 'Application February 2, 1937,
Serial No. 123,728
4 Claims.
(Cl. 51-278)
- This invention relates to improved abrasive
articles and methods of manufacturing the same.
or polishing
the articles
is concerned
of. a mass
5 221.18g):gingo?gg?g?agg?gguég ?nely dmded
Bonded abrasive products, as ‘typi?ed by abra'sive wheels and distinguished from coated abrasive products such as are commonly referred to as
10 “sandpaper”, maybe divided into two general
classes. One of these classes comprises the ord.i-'~
‘ nar
wheel, the
Example I
275 gram;
in 82 of
of a y was me
5' co 0 '
1240 grams of ?nely pulverized levigated alumina
is uniformlysuspended in the solution by stirring. 5
A catalyst cumming of 3 gram-5 of metallic
Sodium reacted ill-100 00- Of anhydrous methyl;
alcohol 15? _stirred into the suspension uni omuy
and the mlx is quickly mured into a mold‘
1 10
In about ?ve minutes a’ gel 01' polyvinyl alcoho
function of‘ with levigated alumina in suspension is formed,
' whi'schgis to gemove materilal qugitities of the ‘ the polyvmyl alcohol being formed by“ substltu'
work beinglishin
while. the
other subdivision
mm of ti“: on groups é” tilee meggi'l
a'llcohot- ftor
the rima
the ace 3' e groups 0
“37 ace 9‘ e‘
of whichpig to dgvelop ?nish wlEile the, gilt-naval Nliet?yl acetate is formed along with the polyvinyl
15' includes
of material isxa secondary consideration. Articles
a co °1'
the ?rsttoclass
are clearance
usually rather
for the
i n Ems
O a’ i613;
Fr ' atnow?dbgo
‘t Dun‘?
20 material which has been abraded and to assist
breakdown of the article in use as the abrasive
I g
time’ which may ast abou
r y “S or e58’ 20
accordmg - to the drying conditions present' 8'
particles on the'su'rface of the article become mixgure 0; metrayél alcolziol gndnr?ghyéha‘ig?ge
~ dulled.v Polishing articles, on the other hand,
exutesf at? ‘gay
531mm‘, ' d
g1 e
l r
are comparatively dense and may, in effect, be tp1?at 0h
6 ‘gigs b he 6;“ a 01: sis? 531we
consideredasamass of bonding material containt 9 ex“ 8 s“ 5 “me evapora e n o
igirg?fadmi °r . mashing particles embedded
The present invention
is concerned with im-‘
by the usual1 known methods and machined into
proved articles of this second class and methods
30 of making such articles, which contain ?nely
the form of a wheel which will be found to be
superior for ce'i'tain uses such as the‘sharpemng 30
of razor blades.
The block thus formed/is drilled and machined
and to
In an alternative method the mixture is poured
It is accordingly an object of. the ‘invention to Up°n
amunddry8’ imetlal
a?“ Jt'ilsghbzfg?e
th‘; “1151";list‘y
“8 t 15 mm
e at °r
provide improve'dabrasive or polishing articles
35 consisting essentially of a mass of organic bond~
'ing material having abrading or polishing par-
attached to the mass of cast material
‘ Example H
ticles distributed therethrough. A further object '
of the invention is the provision of methods of
2753mm 0f polymerized vinyl acetate 8-H: 046
manufacturing such articles.40
solved in 550 grams of anhydrous methyl alco
The method of the invention consists essen-
hol. 1240 grams of 400 mesh silicon carbide are 40
tially in ?rst preparing a suspension of finely
divided particles in a liquid which is adapted to
be solidi?ed to form a mass of organicmaterial
, carrying ?nely divided polishing particles dis45 tributed uniformly in the mass. There are a
number of types of liquids which can be used -
stirred into the soluttion. 100 grams glycerine
diluted with 100 grams methyl alcohol are slowly
A catalyst consisting of 3 grams metallic sodi
um reacted in 100 cc. of anhydrous methyl alco- 45
hol is stirred into the suspension. ‘_ A gel quickly
and the particular method employed in carrying
formed from which the volatile methyl alcohol
out ' the invention depends speci?cally‘ on- the
and methyl acetate evaporated, leaving the glyc
character of the liquid material employed.
erin as a plasticizer for the polyvinyl alcohol. .
'50 - I will now describe the invention ‘by reference
to a number of‘ speci?c examples; It is to be
After drying until the alcohol odor. is absent, this 50
mass is tough and leathery. Thin shoes are flex
understood that these examples are given ;for
ible and very suitable for hand polishing brass
the purpose of illustrating the invention and
and other metals.
'are'not intended to be limitative or the scope of.
, $5 the invention.-
> The polyvinyl alcohol gels may be modi?ed by
‘incorporating heat hardenable phenolic rain 66
dissolved in methanol in the methanol solution
of polyvinyl acetate. A sodium methylate cat
alyst may be used to cause gel formation. The
presence of the phenolic resin slows the reaction
at room temperature. The reaction, however,
may be speeded by re?uxing the mixture until
the gel formation starts and the mixture may
then be poured into suitable molds for the com
pletion of the gel formation. The resulting gel
10 with. abrasive in suspension may be dried and
baked to harden the mixture. The phenolic resin
in the gel after baking hardens and ins'olubil
izes it.
While the use of very ?ne abrasives has been
15 illustrated in the examples, this invention is in
no way limited to the use of very ?nely divided
material. Coarser abrasives may be used but it
is desirable to thicken the viscosity “of the solu
tion and solidify the solution quickly to prevent
20 settling of the abrasive.
Other modi?cations employed in the manufac
ture of abrasive products may also be employed.
Such modi?cations include the. use of modifying
agents to alter the characteristics of the organic
25 material. Such modifying agents include, for ex
ample, plasticizing agents to increase the elastic
ity of the bond and ?lling materials. In‘solubiliz- . ing treatments such as the inclusion of compatible
insolubilizing agents to the mix or treatment after
30 gelation as by exposure to the fumes of a vola
the materials and methods therein described but
may be otherwise practiced as de?ned by the
appended claims.
I claim:
1. In a method of making abrasive articles,
the steps which comprise preparing a. suspension
,of abrasive particles in a solution of a polyvinyl
ester in an alcohol and adding a catalyst to
cause reaction between the alcohol and the ester,
whereby there is formed a solid mass of polyvinyl 10
alcohol containing abrasive particles suspended
therein and distributed uniformly therethrough.
2. The method of making an abrasive article
consisting essentially of a binder and an abrasive
material which comprises suspending ?nely pul 15
verized abrasive material in a solution of poly
merized vinyl acetate in an alcohol and adding
a catalyst to cause a reaction whereby there is
formed a dense solid mass of polyvinyl alcohol
carrying the abrasive material uniformly distrib 20
uted therethrough.
3. A method oftmaking abrasive articles which
comprises the steps of dissolving polymerized
vinyl acetate in anhydrous methyl alcohol, stir
ring ?nely pulverized levigated alumina into the 25
solution thus formed, adding to the solution a
catalyst consisting of metallic sodium reacted
in anhydrous methyl alcohol, and allowing the
mixture to set until a polyvinyl alcohol gel thus
formed has hardened.
4. ‘ method of making abrasive articles com
tile aldehyde may also be employed.
prising the steps of dissolving polymerized vinyl
Abrasive products made in- accordance with ‘acetate in anhydrous methyl alcohol, stirring
the invention have been found to be particularly ?nely pulverized abrasive into the solution thus
well adapted for polishing operations such as the formed, and adding a catalyst to cause a reaction
?nal ?nishing of safety razor blades or steel
and thus form a gel of polyvinyl alcohol, with
rolls used in the ?nal rolling of sheet materials.~ the abrasive particles. uniformly suspended
While I have illustrated the invention by ref
erence to a number of specific examples, it is to therein,
be understood that the invention is not limited to
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