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Патент USA US2369689

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2,369,689
UNITED STATES PATENT OFFICE
Patented Feb. 20, 1945
2,369,689
_ m w ,9,
ABBASIVE ARTICLES AND METHODS or
MANUFACTURING THE SAME
Norman P.‘ Robie, Lewiston, and Osborne L.
iii...
W ,5... 3...,
g
;
iii... t.) u a .-... a
N. Y., assignors to The
Mahlman, Kenmore,
Company, Niagara Falls, N. Y., a
Carborundum
corporation of Delaware
No Drawing. Application November 6, 1941,
Serial No. 418,010
12 Claims.
(on. 51—--298) '
su?lcient viscosity to be satisfactory in the pro
duction of both molded and coated articles and
This invention relates to abrasive articles and
methods of manufacturing the same. More
speci?cally, the invention is concerned with the
which will heat-harden to a substantially in
fusible condition without the generation of
gaseous icy-products. A further object of the
invention will be apparent from the consideration
of the ltollowing speci?cation.
production of abrasive products in which the
bond comprises the resinous reaction product.
of an unsaturated monomeric material with the
unsaturated esteri?cation. product or an alcohol
and a polybasic acid.
,
_
I We have discovered that the objects set forth
above can be accomplished by employing, as a
'
‘Although the invention is adapted to the pro
binder for the abrasive grains, the reaction
duction of various types of abrasives, including 10 product of a mixture of unsaturated monomeric
both the coated abrasives as represented by the
materials with unsaturated esteri?cation prod
conventional “sandpaper" and the bonded
ucts of alcohols with polybasic organic acids.
articles such as abrasive wheels or stones, it is
The unsaturation of the esters, which are com
particularly well adapted for production of very
monly employed in the form of polyesters, can
be provided by the use of either an unsaturated
alcohol or an unsaturated polybasic acid or both.
The polybasic acids are characterized by the
dense bonded articles which are substantially
free from pore space. Such articles are of parti
cular utility in the ?eld of ?ne ?nishing and in
cases where it is desired that the abrasive article
presence Oif
shall maintain its grinding face while grinding
two or more carboiwl
groups
(COOH), the hydrogen of which combines with
as, for example, in the ?eld or thread grinding. 20 the hydroxyl group (OH) , which is characteristic
A very large part or the resin bonded abrasive
of alcohols, to form water and join the remain
articles is made with a phenol aldehyde con
ing part of alcohol and acid groups into an ester.
densation product as the bond. Such products
When a polybasic acid containing two carboxyl
have a wide utility, but the phenol aldehyde
groups, reacts with an alcohol containing two
resins are not well suited for the production 25 hydroxyl groups, the reaction product is of the
of extremely dense wheels because during the
nature of a. chain in which one carboxyl of the
curing or heat-hardening of the resin gaseous
acid joins to one hydroxyl of an alcohol molecule
products are evolved, and unless the abrasive
the other carboxyl group of the acid being re
article has-a certain minimum porosity to allow
acted'with a different alcohol molecule. Such
for the escape of these gases the article swells 30 products are herein referred to as “polyesters”
and bloats and is therefore unsatisfactory.
because they comprise molecules made up from
Attempts have been made to make very dense
a plurality of individual alcohol and acid mole
articles by the polymerization of monomeric ma
cules joined together as distinguished from the
terials such as vinyl esters or the esters of acrylic
acid. Such polymerization does not involve the
evolution of gaseous lay-products and is there
fore adapted to the production of dense, non
35
porous bodies. However, this process is unsat
isfactory for two principal reasons. In the ?rst
ordinary esters, which constitute individual and
single ester molecules.
The polyesters formed in the primary stages
of our invention are ordinarily very viscous
liquids. Since the water formed by esteri?ca
tion is produced during this primary stage re
place, the monomeric materials are thin liquids 40 action we provide a. part of the bond in the
and it is di?icult to get a stable and homogeneous
partially reacted condition such that no gaseous
suspension of the abrasive particles in such
or volatile by-products are produced by further
liquids. In the second place, the polymerization
esteri?cation. Consequently when the ?nal or
products are permanently thermoplastic as dis
heat-hardening ‘process is carried out the re
tinguished from the heat-hardened iniusible type
action is not accompanied by the evolution of
obtained by the reaction of phenol with alde
volatile materials because the ?nal step is a mere
hydes, and when such articles are used for dry
grinding the bond scritens and both smears the
work with the bond and picks up the detritus
formed by grinding to cause the articles to be
come loaded.
combination at the double bond, such as takes
vention to provide abrasive articles in which the
bond is infusible and which have substantially
no porosity. Another object of the invention is
the provision of abrasive articles and method
oi'manufacturing such articles which are dense,
accordance with our invention is brought about
by reason of the fact that when the unsaturated
polyesters oi polybasic acids are mixed with
It is accordingly an object of the present in- '
place in the ordinary linear polymerization of
such materials as vinyl acetate or the acrylic
acid compounds, the product or which is herein
referred to as an “additive reaction product.”
The iniusibility oi the products iormed in
polymerizable monomeric materials the chains
formed during the polymerization are joined by
hard and substantially free from porosity. An
the other component of the reaction mixture
other obiect-of the invention is the provision out
and the two or three dimensional molecule thus
60.
a bond for abrasive articles which will have
'2
aseassa '
formed is more‘ heat-resistant, whereas the
chain length we may obtain the necessary
straight chain molecules of such materials as
amount of unsaturation by using an unsaturated
polyvinyl acetate are softenable by heat. The
monobasic acid to limit the chain length. For
process which we have described for the fema
instance. a short chain polyester with three un
tion of polyesters requires the use of both poly
saturations may consist of one mole of fumaric
hydric alcohols and polybasic acids. As an al
acid, two moles of glycol and two moles of metha
ternative we may employ unsaturated mono
crylic acid. The fumaric acid will be in the
hydric alcohols with unsaturated polybasic acids
center with a mole of glycol on each ,side and the
to form esters which polymerize by the conven
methacrylic acid on each end.
tional additionreaction brought about by the
The invention will now be further described
with reference to specific examples. It is to be
joiningi of the monomeric esters at some of the
double bonds of the esters. These partially poly
understoodv that these examples merely illustrate
merized esters still contain suiiicient unsatura
tion to be capable of interaction with the poly
merizable monomeric materials to form the in
certain embodiments of the invention which is
capable of'numerous variations and is to be
limited only by the appended claims.
Example I.--We have found the new type of
bond to be suitable for uniform, very hard, dense
fine grit wheels used for razor honing. The fol
lfusible binders characteristic of our invention.
We have found that polyesters formed by the
reaction of diethylene glycol, which is a- dihy-'
dric alcohol, with maleic or fumaric acids are
lowing example illustrates this type of wheel.
well adapted for use in the forming of our bind 20
The polyester of diethylene glycol fumarate
ers where the polyesters are formed from poly
was prepared by heating 1044 gms. furnaric acid
hydric alcohols. For the production of esters
with 990 gms. of diethylene glycol for seven
with a monohydric unsaturated alcohol we have
hours on an oil bath reaching 200° C. in 21/4
used allyl alcohol to form dlallyl maleate or
hours and maintaining that temperature for the
fumarate. For the polymerizable monomeric 25 remaining time. Carbon dioxide was bubbled
materials we have used vinyl compounds such as
through the ?ask to agitate the mixture and
vinyl acetate and styrene and found them to be
prevent oxidation. A resinous balsam resulted.
well suited to our purposes. Instead of these
Vinyl acetate and styrene monomers were sepa
particular materials we can employ other poly
rately distilled to remove the inhibitor and the
hydric alcohols such as ethylene glycol; tri 30 reaction
mixture for forming the bond was then
methylene glycol; tri and tetraethylene glycol;
made in the following proportions:
glycerol; propylene glycol, monoethylin, and un
’Grams
saturated glycols such as obtained by hydrolysis
Diethylene glycol fumarate polyester _____ -_ 514
of butadiene dibromide, and other polybasic un
Inhibitor free vinyl acetate monomer _____ __ 163
saturated acids such as aconitic, citraconic,
itaconic, vinylmalonic, the terpene-maleic an
hydride’ adduct known as "Petrex” and the like.
'
Inhibitor free styrene monomer _________ __
88
Benzoyl peroxide _______________________ __
1.9
Other unsaturated monohydric alcohols which
The polyester was warmed slightly anddissolved
in the vinyl acetate, the benzoyl peroxide was
alcohol, methyl vinyl carbinol, divinyl carbinol, 41 dissolved in styrene, and the two solutions were
3-chloro-2-butanol-1, butadiene-1, 2-01-4, crotyl
mixed. The above bond mixture hardens at
alcohol and the like.
130° F. to a very hard light amber colored glass
Instead of the vinyl compounds vinyl acetate
like resin which, when heated will char without
and styrene speci?cally referred to above, we may
fusion.
employ, as the unsaturated monomeric compound 45 The liquid resin mixture was uniformly ‘mixed »
various monomers, having solvent action on the
with 750 gms. of very ?ne calcined alumina from
esters and polyesters, such as vinyl chloracetate
the Bayer process and forced thru a fine screen
and other vinyl-esters,, vinyl ketones, vinyl
to insure uniformity. The creamy syrup was
ethers, esters of acrylic and methacrylic acid,
then poured into cylindrical molds to give cast~
acrolein, acrylonitrile and the like. With these 51 ings 5" long x 3"_in diameter. The cast mix
monomers which are soluble may be blended un
ture prior to hardening was subjected to a me.
saturated monomers which are without a sol
chanical vibration to cause all air bubbles to rise
vent action or are normally gaseous such as
to the top where they can be removed. The
casting was hardened at 130° F. for 48 hours.
butadiene, vinyl chloride, coumarone. indene.
isobutylene, chloroprene, vinyl acetylene and the 55 When cured it had shrunk awayv from the mold
facilitating easy removal for ?nal surfacing and
like. when gaseous monomers are used the
insertion of the arbor. The product was a high
hardening may be performed under pressure.
ly satisfactory razor blade honing wheel.
Since we have found it is only necessary to
Example II.—-Hard dense wheels suitable for
provide occasional double bonds in the poly
esters, we have successfully carried out our in Oi thread grinding were produced from the follow
ing composition using the procedure of Ex
vention by using a mixture of an unsaturated
ample I.
polybasic acid with a saturated polybasic acid
‘ such as succinic acid, to form the polyesters. In
Grams
180 grit fused alumina _________ -_~. _______ -- 440
such cases the degree of unsaturation depends
upon the relative proportion of the unsaturated 05 400 grit fused alumina _________________ __'_ 100
we may use include propargyl alcohol, methallyl
acid to the saturated acid, and by the selection
Diethylene glycol fumarate polyester.v ____ -- 140
of different kinds of acids and di?erent propor~
portions of unsaturated and saturated acids we
Vinyl acetate monomer ___________ -..-.... ..-
45
Styrene
monomer ______________ _.- ______ -_
25
Benzoyl
peroxide ____ -.. _____ __; _________ _-
0.5
are able to produce binders having quite differ 70
‘
ent physical characteristics.
The dense glass-like nature of this bond aids the
grinding wheel to retain the shape of the grind
ing surface during the thread grinding operation.
Example IIL-The polyesters may be diluted‘
length of the polyester. with polyesters of short 75 with su?icient vinyl resin monomer to give a
The polyesters we use may be further modi
?ed by using a monobasic acid with a polybasic
acid. The monobasic acid limits the chain.
3
~ aseaaee
An abrasive wheel employing this material was _
made of the following compositions:
70 parts of this Petrex modi?ed polyester was
sticky liquid adhesive very suitable for adhering
abrasive grain to a backing.
.
.
,
100 gms. diethylene glycol-fumarate polyester
mixed with:
'10 parts styrene monomer
0.4 parts benzoyl peroxide
150 parts ?nely pulverized calcined alumina from
made in accordance with Example I was mixed
with 18 cc. diallyl fumarate and 32v cc. vinyl
acetate monomer containing 0.2 gm. benzoyl
peroxide. A sticky viscous liquid resulted. This
was coated onto heavy 130# manila paper and
the Bayer process.
)
30 grit fused alumina was spread uniformly over
This mix was run through a ?ne screen and cast
the adhesive layer. Another light adhesive layer 10 into a razor honing wheel. . The wheel was then
was spread over the grain. The coated paper
hardened at 120° F. to produce a uniform solid
was then cured at 150° F. for 461/2 hours and then
wheel with surfaces free from pores, and suitable
at 250° F. for 21/2‘ hours. The resulting cured
for honing razor blades.
resin held the grain very tenaciously to . the
We have described unsaturated polyesters suit
15
paper.
able for our invention whose unsaturation is duev
to the unsaturated acid used. We may also pro
duce our polyesters with an unsaturated alcohol
Example IV.—159 parts diethylene glycol was
esterl?ed with 174 parts aconitic acid while
agitating with a CO: stream by heating to 150°C.
such as allyl alcohol or with an unsaturated
in one hour, raising the temperature from 150 to
glycol such as butenediol and a saturated or an
170° C. in 1/2 hour and holding the temperature 20 unsaturated acid.
'
at 170° C. for 2 hours. The'aconitic acid poly
ester became a viscous balsam more quickly than
The high strength of our binder may be illus-'
trated by the following data obtained by casting
the fumarate polyester. The aconitic acid ester
also dissolves vinyl acetate more slowly than, the
fumarate polyester.
25
~
6" x 1" square test bars of ?lled and un?lled
resin and determining its modulus of rupture.
A resinous solution was prepared by adding 0.2
Resin composition
part benzoyl- peroxide dissolved in 25 parts vinyl
acetate, to 75 parts of the aconitic acid polyester.
This resinous solution has sufficient acidity due
to unesteri?ed carboxyl groups in the polyester 30
to be easily emulsi?ed by an aqueous solution
of sodium hydroxide. This emulsion was coated
.
No. 1
No. 2
Diethylene iumei'ate polyester. _
_.parts._
Vinyl acetate monomer ..... _.
. _ .do____
109 35
109
36
Styrene monomer ........... ._
_do____
l9
l9
Benzoyl peroxide ............. __
_..do.._.
0. 4
0. 5
200 mesh and ?ner fused quartz ............. _.do_.__ ...... ._
150
Modulus of rupture ............................... __ i3, 160 6. 320
onto strong manila paper and the coated paper
was covered with fused alumina abrasive. The
The compositions were hardened 64 hours at 125°
emulsion was hardened by heating for 40 hours 35 F. and then 7 hours at 200° F. The un?lled test
bar was hard and glassy bending slightly in the
at 125° F. and 48 hours‘at' 200° F. A ?exible
testing machine before shattering‘ into many
strong adhesive resulted holding the abrasive
.
'pieces. The quartz ?lled bar resembled a piece
Example V.-A hardened molded abrasive
of marble with a hard metallic ring.
It is obvious that the binders and adhesives
bed may be modi?ed by the usual methods.
tenaciously to the backing.
article bonded by a phenolic resin was made 40
much more water resistant by ?lling the pores _
with the following composition:
Diethylene glycol fumarate polyester as per
Parts
,5.
ExampleI __________________________ ..- 175.5
Vinyl acetate monomer ________________ __ 58.5
Styrene monomer _____________________ _. 58.5
Benzoyl peroxide ______________________ __
0.5
The article ?lled and submerged in the composi
tion was warmed slightly above roomv tempera
ture until the liquid formed a soft gel. The ex
cess soft gel was then sliced off the abrasive
article and the filled article further baked at
130° F. until the gel hardened to a hard glass
like resin ?lling the pores of the abrasive article.
Such a filled abrasive article is adapted for use
in warm water like a pulp wheel because of
its resistance to water.
Example V_I.—-The solubility of our'polyester
toward vinyl monomers may be modi?ed by the
addition of a terpene-maleic anhydride adduct
known as “Petrex.”
This modi?cation also re
duces the tendency of the resin to crack when
curing quickly. A "Petrex” modi?ed polyester
was produced as follows:
Parts
Diethylene glycol ______________________ .._ 80
Fumaric acid ______ ..__ __________________ _- 43.5
Petrex acid _____________________ __'_ ____ -_ 80
This mixture was heated, while bubbling nitrogen
into the mix, taking 21/2 hours to reach 195°- C.
and maintaining this temperature for two hours.
A light amber, sticky, viscous balsam-like resin
resulted.
'
descri
Polymerization may be carried out under differ
ent conditions to modify the resin properties.
Natural and synthetic resins and drying oils,
may be blended with either the esters, polyesters
or monomeric hardening agent. For example
saturated soluble, uncured alkyd resins may be
blended with our unsaturated polyesters. Poly
mers may be dissolved in the monomeric mate
rial before blending with the polyester and
hardening. Catalysts, organic and inorganic
?llers, dyestuffs,‘ plasticizers and anticatalysts
may also be employed.
We have described our invention with selected
characteristic examples by way of illustration.
It is obvious that modi?cations of the foregoing
examples are possible. These modi?cations are
apparent from the foregoing description and the _
invention is to be limited only by the accompany
ing claims.
We claim:
1. An abrasive article comprising abrasive
grains and a hardened binder comprising the ad
ditive reaction product of a substantially neutral
' unsaturated monomeric material and an unsat
urated esteri?cation product of an aliphatic alco
hol and a polybasic acid.
2. An abrasive article comprising abrasive
70 grains and a hardened binder comprising the
additive reaction product of a substantially neu
tral unsaturated monomeric material with a poly
ester of an aliphatic polyhydric alcohol and an
unsaturated polybaslc acid."
3. An abrasive article comprising abrasive
4
.
a,sea,eaa
grains and a hardened binder comprising the
additive reaction product 01' a substantially neu
tral unsaturated monomeric material with a poly
ester of an unsaturated aliphatic alcohol and a
polybasic acid.
'
g
4. An abrasive article comprising abrasive
grains and a binder comprising the additive reac- ’
tion product or a vinyl compound and an unsat- ,_ -
v _
10. The method of making abrasive products
which comprises preparing an unsaturated poly
ester by reacting an aliphatic alcohol with a poly
‘basic acid, mixing the ester with a substantially
neutral unsaturated monomeric material reactive
therewith and with abrasive grains, and heating
the article to solidify the binder by. bringing about
an additive reaction between the monomeric ma
urated esteri?cation product of an aliphatic alco
' terial and the polyester to cross-link polyester
hol and a polybasic acid.
10 molecules.
5. An abrasive article comprising abrasive
1 11. The method of making a dense abrasive ar
grains and a hardened binder comprising the ad-_
ticle which is substantially free from porosity
ditive reaction product or diethylene glycol tu
which comprises commingling an unsaturated
marate polyester and a vinyl compound.
-
6. An abrasive article comprising abrasive 15 polyester, a substantially neutral unsaturated
monomeric material reactive with the said poly
grains and a, ‘hardened binder comprising the
ester and abrasive grains, shaping an article from '
additive reaction product oi’ a substantially neu
the mixture thus prepared,v and heating the'ar
tral unsaturated monomeric "material and an
ester of an unsaturated aliphatic monohydric
‘alcohol and an unsaturated polybasic acid‘.
ticle to solidify the binder to an infusible state
by bringing about an additive reaction between .
monomeric material and the polyester to
7. Ah abrasive article comprising abrasive 20 the
cross-link polyester molecules.
grains and a hardened binder comprising‘ the
'
12.
The
method
of
making
a
coated
abrasive
additive reaction product of diallyl iumarate and
article which comprises preparing a liquid adhe
a vinyl compound.
~
sive comprising an unsaturated esteri?cation
8. An abrasive article comprising bonded abra
product of an aliphatic alcohol with a polybasic
sive grains molded and hardened to shape and
acid and a substantially neutral unsaturated,
impregnated with an additional hardened binder
monomeric material reactive with the said ester
comprising the additive reaction product or a
i?cation product, coating a backing with such
~~ substantially neutral unsaturated monomeric ma
adhesive
and abrasive grains, and heating the
terial with an unsaturated esteri?cation product
30 article to harden the binder by bringingabout an
of an aliphatic alcohol and a polybasic acid.
additive reaction between the monomeric material
9. An abrasive article comprising abrasive
and the esteri?cation product to cross-link the
grains and a hardened binder comprising the
additive reaction product of a substantially neu
tral unsaturated monomeric material with an un
saturated esterl?cation product 01' an aliphatic
polyhydric alcohol and-‘both a monobasic and a
polybasic acid.
7
.
esteri?cation product molecules.
NORMAN P.‘ RDBIE.
-
OSBORNE L. MAHLMAN.
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