U.S. patent application number 11/398848 was filed with the patent office on 2006-11-02 for abrasive article having reaction activated chromophore.
This patent application is currently assigned to SAINT-GOBAIN ABRASIVES, INC.. Invention is credited to Xiaorong You.
Application Number | 20060242910 11/398848 |
Document ID | / |
Family ID | 36691366 |
Filed Date | 2006-11-02 |
United States Patent
Application |
20060242910 |
Kind Code |
A1 |
You; Xiaorong |
November 2, 2006 |
Abrasive article having reaction activated chromophore
Abstract
An abrasive article has a layer including an epoxy constituent,
a cationic photointiator within the epoxy constituent, and a latent
colorant configured to change color in response to activation of
the cationic photoinitiator.
Inventors: |
You; Xiaorong; (Shrewsbury,
MA) |
Correspondence
Address: |
LARSON NEWMAN ABEL;POLANSKY & WHITE, LLP
5914 WEST COURTYARD DRIVE
SUITE 200
AUSTIN
TX
78730
US
|
Assignee: |
SAINT-GOBAIN ABRASIVES,
INC.
Worcester
MA
01615-0138
|
Family ID: |
36691366 |
Appl. No.: |
11/398848 |
Filed: |
April 6, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60669413 |
Apr 8, 2005 |
|
|
|
Current U.S.
Class: |
51/297 ; 51/298;
51/307; 51/308; 51/309 |
Current CPC
Class: |
B24D 3/344 20130101;
C09K 3/14 20130101; B24D 11/00 20130101; B24D 3/02 20130101 |
Class at
Publication: |
051/297 ;
051/298; 051/307; 051/308; 051/309 |
International
Class: |
B24D 11/00 20060101
B24D011/00; B24D 3/02 20060101 B24D003/02 |
Claims
1. An abrasive article having a layer comprising: an epoxy
constituent; a cationic photointiator within the epoxy constituent;
and a latent colorant configured to change color in response to
activation of the cationic photoinitiator.
2. The abrasive article of claim 1, further comprising an acrylic
constituent and a radical generating photoinitiator.
3. The abrasive article of claim 2, wherein the layer comprises
about 0.1 wt % to about 60 wt % of the acrylic constituent.
4-7. (canceled)
8. The abrasive article of claim 2, further comprising a second
latent colorant configured to change color in response to
activation of the cationic photoinitiator.
9-10. (canceled)
11. The abrasive article of claim 1, wherein the layer comprises
about 10 wt % to about 90 wt % of the epoxy constituent.
12-15. (canceled)
16. The abrasive article of claim 1, wherein latent colorant
exhibits a specific color based on curing of the epoxy
constituent.
17. (canceled)
18. An abrasive article comprising: a polymer matrix; a reaction
activated chromophore within the polymer matrix; and particulate
abrasive grains.
19. The abrasive article of claim 18, wherein the reaction
activated chromophore is formed from a latent colorant and a curing
byproduct.
20. The abrasive article of claim 19, wherein the latent colorant
is selected from the group consisting of a triaryl methane-based
color former, a diphenyl methane-based color former, a
thiazine-based color former, a spiro-based color former, a
lactam-based color former, a fluoran-based color former, an
isobenzofuranone-based color former, and any combination
thereof.
21. The abrasive article of claim 18, wherein the polymer matrix is
free of particulate pigment.
22. The abrasive article of claim 18, wherein the reaction
activated chromophore comprises an organic chromophore.
23. The abrasive article of claim 18, wherein the polymer matrix
comprises a polymerized cationically polymerizable constituent.
24-30. (canceled)
31. The abrasive article of claim 18, wherein the polymer matrix
comprises a polymerized radically polymerizable constituent.
32-37. (canceled)
38. The abrasive article of claim 18, wherein the particulate
abrasive grains are selected from the group consisting of silica,
alumina, zirconia, silicon carbide, silicon nitride, boron nitride,
garnet, diamond, cofused alumina zirconia, ceria, titanium
diboride, boron carbide, flint, emery, alumina nitride, and any
combination thereof.
39. The abrasive article of claim 38, wherein the particulate
abrasive grains have a median grain size between 0.1 microns to
1500 microns.
40-41. (canceled)
42. The abrasive article of claim 18, wherein the abrasive article
is a coated abrasive article.
43-44. (canceled)
45. The abrasive article of claim 42, wherein the coated abrasive
article is an engineered abrasive article.
46. The abrasive article of claim 18, wherein the abrasive article
is a bonded abrasive article.
47. The abrasive article of claim 18, further comprising a second
reaction activated chromophore.
48. The abrasive article of claim 47, wherein the reaction
activated chromophore has a first electromagnetic energy absorption
profile and the second reaction activated chromophore has a second
electromagnetic energy absorption profile.
49-50. (canceled)
51. The abrasive article of claim 47, wherein the reaction
activated chromophore is activated based on a different reaction
condition than the second reaction activated chromophore.
52. An abrasive article comprising a reaction activated
chromophore.
53. The abrasive article of claim 52, wherein the reaction
activated chromophore is formed from a latent colorant and a curing
byproduct.
54. (canceled)
55. The abrasive article of claim 52, further comprising a polymer
matrix comprising a polymerized cationically polymerizable
constituent.
56-59. (canceled)
60. The abrasive article of claim 52, further comprising
particulate abrasive grains.
61-94. (canceled)
Description
CORRESPONDING APPLICATIONS
[0001] The present application claims priority from U.S.
Provisional Patent Application No. 60/669,413, filed Apr. 8, 2005,
entitled "ABRASIVE ARTICLE HAVING REACTION ACTIVATED CHROMOPHORE,"
naming the applicant Xiaorong You, which application is
incorporated by reference herein in its entirety.
FIELD OF THE DISCLOSURE
[0002] This disclosure, in general, relates to abrasive articles
and methods for forming same.
BACKGROUND
[0003] Abrasive articles, such as coated abrasives and bonded
abrasives, are used in various industries to machine workpieces,
such as by lapping, grinding, or polishing. Machining utilizing
abrasive articles spans a wide industrial scope from optics
industries, automotive paint repair industries, to metal
fabrication industries. In each of these examples, manufacturing
facilities use abrasives to remove bulk material or affect surface
characteristics of products.
[0004] Surface characteristics include shine, texture, and
uniformity. For example manufacturers of metal components use
abrasive articles to fine and polish surfaces, and oftentimes
desire a uniformly smooth surface. Similarly, optics manufacturers
desire abrasive articles that produce defect free surfaces to
prevent light diffraction and scattering.
[0005] Manufactures also desire abrasive articles that have a high
stock removal rate for certain applications. However, there is
often a trade-off between removal rate and surface quality. Finer
grain abrasive articles typically produce smoother surfaces, yet
have lower stock removal rates. Lower stock removal rates lead to
slower production and increased cost.
[0006] Particularly in the context of fine grained abrasive
articles, commercially available abrasives have a tendency to leave
random surface defects, such as scratches that are deeper than the
average stock removal scratches. Such scratches may be caused by
grains that detach from the abrasive article, causing rolling
indentations. When present, these scratches scatter light, reducing
optical clarity in lenses or producing haze or a foggy finish in
decorative metal works. Such scratches also provide nucleation
points or attachment points that reduce the release characteristics
of a surface. For example, scratches in sanitary equipment allow
bacteria to attach to surfaces, and scratches in polished reactors
allow formation of bubbles and act as surface features for
initiating unwanted reactions.
[0007] Loss of grains also degrades the performance of abrasive
articles, leading to frequent replacement. Frequent abrasive
article replacement is costly to manufacturers. As such, improved
abrasive articles and methods for manufacturing abrasive articles
would be desirable.
SUMMARY
[0008] In a particular embodiment, an abrasive article has a layer
including an epoxy constituent, a cationic photointiator within the
epoxy constituent, and a latent colorant configured to change color
in response to activation of the cationic photoinitiator.
[0009] In another exemplary embodiment, an abrasive article
includes a polymer matrix, a reaction activated chromophore within
the polymer matrix, and particulate abrasive grains.
[0010] In a further exemplary embodiment, an abrasive article
includes a reaction activated chromophore.
[0011] In an additional exemplary embodiment, a method of
manufacturing an abrasive article includes initiating a curing
process in an abrasive article workpiece. The abrasive article
workpiece includes a polymer precursor and a latent colorant. The
latent colorant is configured to change color in response to
curing. The method also includes determining a target color of the
abrasive article workpiece and terminating the curing process when
the abrasive article workpiece exhibits the target color.
[0012] In another exemplary embodiment, a method of controlling
abrasive product quality includes forming an abrasive product
comprising a polymeric matrix and a reaction activated chromophore.
The reaction activated chromophore is configured to exhibit a color
characteristic based on a state of curing. The method also includes
inspecting the abrasive product based on the color characteristic
and categorizing the abrasive product based on the color
characteristic.
[0013] In a further exemplary embodiment, an abrasive article
includes a layer patterned to form a surface structure. The layer
includes a material including a polymeric matrix and a reaction
activated chromophore, and includes abrasive grains bonded to the
layer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The present disclosure may be better understood, and its
numerous features and advantages made apparent to those skilled in
the art by referencing the accompanying drawings.
[0015] FIG. 1 includes an illustration of an exemplary coated
abrasive article.
[0016] FIG. 2 includes an illustration of an exemplary structured
abrasive article
[0017] FIG. 3 includes an illustration of an exemplary bonded
abrasive article.
[0018] The use of the same reference symbols in different drawings
indicates similar or identical items.
DESCRIPTION OF THE DRAWING(S)
[0019] In a particular embodiment, the disclosure is directed to an
abrasive article having a layer that is formed of a polymer matrix.
The polymer matrix includes a reaction activated chromophore
configured to indicate a state of curing. In one exemplary
embodiment, the reactive chromophore includes a latent colorant and
a curing byproduct. For example, the curing byproduct may be a
byproduct of activating a photoinitiator. The abrasive article may
also include particulate abrasive grains.
[0020] In another embodiment, the disclosure is directed to a
method of manufacturing an abrasive article. The method includes
initiating a curing process on a workpiece, determining a target
color exhibited by the workpiece and terminating the curing process
based on the target color. The curing process may include photo
curing or thermal curing.
[0021] In a further exemplary embodiment, the disclosure is
directed to a method of controlling abrasive product quality. The
method includes forming an abrasive product having a polymer matrix
and a reaction activated chromophore, inspecting the abrasive
product for a color characteristic, and categorizing the abrasive
product based on the color characteristic. The color characteristic
may, for example, be a target color or color uniformity.
[0022] Generally, the abrasive article is formed by curing a binder
formulation. The binder formulation typically includes polymer
precursors or polymerizable constituents. For example, the binder
formulation may include cationically polymerizable constituents or
may include radically polymerizable constituents. In addition, the
binder formulation includes a catalysts or an initiator, such as a
photoinitiator or a thermal intiator, to initiate and facilitate
curing. In one particular embodiment, the binder formulation
includes a latent colorant. The latent colorant may react with
byproduct of the curing, such as species derived from activated
initiators, to change color.
[0023] The abrasive article also includes abrasive particles. In
one embodiment, the binder formulation is used as a compliant
layer, a make coat or a size coat in a coated abrasive article.
Abrasive grains may be deposited on the make coat and be overcoated
with a size coat. In another embodiment, the abrasive grains are
mixed with the binder formulation, a mold is filled with the
mixture, and the mixture is cured to form a bonded abrasive
article.
[0024] In an exemplary embodiment, the binder formulation includes
a cationically polymerizable constituent. For example, the
cationically polymerizable constituent may have epoxy functional
groups or oxerane functional groups.
[0025] The constituents including epoxy functional groups, also
referred to as epoxy constituents, are cationically curable, by
which is meant that polymerization or crosslinking of the epoxy
group may be initiated by cations. The epoxy constituents can be
monomers, oligomers or polymers and are sometimes referred to as
"resins." Such materials may have an aliphatic, aromatic,
cycloaliphatic, arylaliphatic, or heterocyclic structure. The epoxy
constituents may include epoxy groups as side groups, or the epoxy
groups may form part of an alicyclic or heterocyclic ring system.
Epoxy groups may also be bound to, for example, siloxane containing
backbones.
[0026] The epoxy constituent may, for example, include at least one
liquid component, such that the combination of materials is a
liquid. Thus, the epoxy constituent can be a single liquid epoxy
material, a combination of liquid epoxy materials, or a combination
of liquid epoxy material(s) and solid epoxy material(s) soluble in
the liquid.
[0027] An example of a suitable epoxy constituent includes
polyglycidyl or poly(methylglycidyl) ester of polycarboxylic acid,
poly(oxiranyl) ether of polyether, epoxidised unsaturated fatty
acid, or any combination thereof. The polycarboxylic acid can be
aliphatic, such as, for example, glutaric acid, adipic acid and the
like; cycloaliphatic, such as, for example, tetrahydrophthalic
acid; or aromatic, such as, for example, phthalic acid, isophthalic
acid, trimellitic acid, or pyromellitic acid; or any combination
thereof. The polyether can be poly(tetramethylene oxide). A
carboxyterminated adduct, for example, of trimellitic acid or
polyol, such as, for example, glycerol or
2,2-bis(4-hydroxycyclohexyl)propane may be used. A suitable
epoxidised unsaturated fatty acid may be obtained from, for
example, linseed oil or perilla oil.
[0028] A suitable epoxy constituent may include polyglycidyl or
poly(-methylglycidyl) ether obtainable by the reaction of a
compound having at least one free alcoholic hydroxy group or
phenolic hydroxy group and a suitably substituted epichlorohydrin.
The alcohol can be acyclic alcohol, such as, for example, ethylene
glycol, diethylene glycol, or higher poly(oxyethylene) glycol;
cycloaliphatic, such as, for example, 1,3- or
1,4-dihydroxycyclohexane, bis(4-hydroxycyclohexyl)methane,
2,2-bis(4-hydroxycyclohexyl)propane, or
1,1-bis(hydroxymethyl)cyclohex-3-ene; or contain aromatic nuclei,
such as N,N-bis(2-hydroxyethyl)aniline or
p,p'-bis(2-hydroxyethylamino)diphenylmethane.
[0029] Alternatively, the epoxy constituent may be derived from
mono nuclear phenol, such as, for example, from resorcinol or
hydroquinone, or may be based on polynuclear phenol, such as, for
example, bis(4-hydroxyphenyl)methane (bisphenol F),
2,2-bis(4-hydroxyphenyl)propane (bisphenol A), or on condensation
products, obtained under acidic conditions, of phenol or cresol
with formaldehyde, such as phenol novolac or cresol novolac.
[0030] A suitable epoxy constituent alternatively may include
poly(N-glycidyl) compound, which is, for example, obtainable by
dehydrochlorination of the reaction product of epichlorohydrin with
an amine that comprise at least two amine hydrogen atoms, such as,
for example, n-butylamine, aniline, toluidine, m-xylylene diamine,
bis(4-aminophenyl)methane or bis(4-methylaminophenyl)-methane. An
exemplary poly(N-glycidyl) compound also includes an
N,N'-diglycidyl derivative of cycloalkyleneurea, such as
ethyleneurea or 1,3-propyleneurea, or a N,N'-diglycidyl derivative
of hydantoin, such as of 5,5-dimethylhydantoin.
[0031] A further example of a suitable epoxy constituent includes
poly(S-glycidyl) compound, which is a di-S-glycidyl derivative,
which is derived from dithiol, such as, for example,
ethane-1,2-dithiol or bis(4-mercaptomethylphenyl) ether.
[0032] An additional example of an epoxy constituent is
bis(2,3-epoxycyclopentyl)ether, 2,3-epoxy cyclopentyl glycidyl
ether, 1,2-bis(2,3-epoxycyclopentyloxy)ethane,
bis(4-hydroxycyclohexyl)methane diglycidyl ether,
2,2-bis(4-hydroxycyclohexyl)propane diglycidyl ether,
3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane,
3,4-epoxy-6-methylcyclohexylmethyl-3,4-epoxy-6-methylcyclohexanecarboxyla-
te, di(3,4-epoxycyclohexylmethyl)hexanedioate,
di(3,4-epoxy-6-methylcyclohexylmethyl)hexanedioate,
ethylenebis(3,4-epoxycyclohexanecarboxylate),
ethanedioldi(3,4-epoxycyclohexylmethyl)ether, vinylcyclohexene
dioxide, dicyclopentadiene diepoxide,
.alpha.-(oxiranylmethyl)-.omega.-(oxiranylmethoxy)
poly(oxy-1,4-butanediyl), diglycidyl ether of neopentyl glycol, or
2-(3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy)cyclohexane-1,3-dioxane,
or any combination thereof.
[0033] An epoxy resin in which the 1,2-epoxy groups are bonded to
different heteroatoms or functional groups may also be useful. Such
a compound includes, for example, the N,N,O-triglycidyl derivative
of 4-aminophenol, the glycidyl ether glycidyl ester of salicylic
acid, N-glycidyl-N'-(2-glycidyloxypropyl)-5,5-dimethylhydantoin,
2-glycidyloxy-1,3-bis(5,5-dimethyl-1-glycidylhydantoin-3-yl)propane,
or any combination thereof.
[0034] In addition, a prereacted adduct of such epoxy resin with a
hardener is suitable for epoxy resin. A mixture of epoxy
constituents may also be used in the binder formulation.
[0035] In a particular embodiment, an epoxy constituent includes
cycloaliphatic diepoxide. An exemplary cycloaliphatic diepoxide is
bis(4-hydroxycyclohexyl)methane diglycidyl ether,
2,2-bis(4-hydroxycyclohexyl)propane diglycidyl ether,
3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate,
3,4-epoxy-6-methylcyclohexylmethyl-3,4-epoxy-6-methylcyclohexanecarboxyla-
te, di(3,4-epoxycyclohexylmethyl)hexanedioate,
di(3,4-epoxy-6-methylcyclohexylmethyl)hexanedioate,
ethylenebis(3,4-epoxycyclohexanecarboxylate),
ethanedioldi(3,4-epoxycyclohexylmethyl) ether,
2-(3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy)cyclohexane-1,3-dioxane,
or any combination thereof.
[0036] The epoxy constituent can have a molecular weight that
varies over a wide range. In general, the epoxy equivalent weight,
i.e., the number average molecular weight divided by the number of
reactive epoxy groups, is preferably in the range of 60 to
1000.
[0037] Typically, the binder formulation includes from about 10% to
about 90% by weight of the epoxide constituent. Weight percentages
of constituents of the binder formulation are stated relative to
the total weight of the curable components of the composition,
unless specified otherwise.
[0038] The binder formulation may include another cationically
curable component, such as a cyclic ether component, a vinyl ether
component, a cyclic lactone component, a cyclic acetal component, a
cyclic thioether component, a spiro orthoester component, an
oxetane-functional component, or any combination thereof. In a
particular embodiment, an oxetane is a component comprising one or
more oxetane groups, i.e. one or more four-member ring structures
according to formula (5): ##STR1##
[0039] The binder formulation may also include a cationic
photoinitiator. Generally, a cationic photoinitiator that, upon
exposure to actinic radiation, forms cations that initiate
reactions of the epoxy constituents can be used. Such a
photoinitiator includes, for example, an onium salt with anions of
weak nucleophilicity. An example includes halonium salt, iodosyl
salt or sulfonium salt, such as are described in published European
patent application EP 153904 and WO 98/28663, sulfoxonium salt,
such as described, for example, in published European patent
applications EP 35969, 44274, 54509, and 164314, diazonium salt,
such as described, for example, in U.S. Pat. Nos. 3,708,296 and
5,002,856, or any combination thereof. Another cationic
photoinitiator includes metallocene salt, such as described, for
example, in published European applications EP 94914 and 94915. An
additional suitable onium salt initiator or metallocene salt can be
found in "UV Curing, Science and Technology", (Editor S. P. Pappas,
Technology Marketing Corp., 642 Westover Road, Stamford, Conn.,
U.S.A.) Or "Chemistry & Technology of UV & EB Formulation
for Coatings, Inks & Paints", Vol. 3 (edited by P. K. T.
Oldring). In a particular example, a cationic photoinitiator
includes a compound of formula I, II or III below, ##STR2##
[0040] wherein:
[0041] R1, R2, R3, R4, R5, R6, and R7 are, independent of each
other, a C6-C18 aryl-group that may be unsubstituted or substituted
by suitable radicals; L is boron, phosphorus, arsenic, or antimony;
Q is a halogen atom or some of the radicals Q in an anion
LQ.sub.m.sup.- may also be a hydroxy group; and m is an integer
that corresponds to the valence of L plus 1. An example of a C6-C18
aryl group includes a phenyl, a naphthyl, an anthryl, or a
phenanthryl group. A suitable radical includes alkyl, for example,
C1-C6 alkyl, such as methyl, ethyl, n-propyl, isopropyl, n-butyl,
sec-butyl, iso-butyl, tert-butyl, or various pentyl or hexyl
isomers; alkoxy, for example, C1-C6 alkoxy, such as methoxy,
ethoxy, propoxy, butoxy, pentyloxy, or hexyloxy; alkylthio, such as
C1-C6 alkylthio, such as methylthio, ethylthio, propylthio,
butylthio, pentylthio, or hexylthio; halogen, such as fluorine,
chlorine, bromine, or iodine; amino; cyano; nitro; arylthio, such
as phenylthio; or any combination thereof. An example of a halogen
atom Q includes chlorine or fluorine. An anion LQ.sub.m.sup.- may
include BF.sub.4.sup.-, PF.sub.6.sup.-, AsF.sub.6.sup.-,
SbF.sub.6.sup.-, SbF.sub.5(OH).sup.-, or any combination thereof.
In a particular example, the photoinitiator includes a compound of
formula III wherein R5, R6, and R7 are aryl, such as phenyl,
biphenyl, or any combination thereof.
[0042] In another example, the photoinitiator includes a compound
of formula (IV)
[R.sub.8(Fe.sup.IIR.sub.9).sub.c].sub.d.sup.+c[X].sub.c.sup.-d,
(IV)
[0043] wherein, c is 1 or 2; d is 1,2,3, 4 or 5; X is a
non-nucleophilic anion, for example, PF.sub.6.sup.-,
AsF.sub.6.sup.-, SbF.sub.6.sup.-, CF.sub.3SO.sub.3.sup.-,
C.sub.2F.sub.5SO.sub.3.sup.-, n-C.sub.3F.sub.7SO.sub.3.sup.-,
n-C.sub.4F.sub.9SO.sub.3.sup.-, n-C.sub.6F.sub.13SO.sub.3.sup.-, or
n-C.sub.8F.sub.17SO.sub.3.sup.-; R8 is a pi-arene; and R9 is an
anion of a pi-arene, such as a cyclopentadienyl anion. An example
of a pi-arene or an anion of pi-arene is found in published
European patent application EP 94915. An additional example of a
pi-arene includes toluene, xylene, ethylbenzene, cumene,
methoxybenzene, methylnaphthalene, pyrene, perylene, stilbene,
diphenylene oxide, diphenylene sulfide, or any combination thereof.
In a particular example, the pi-arene is cumene, methylnaphthalene,
or stilbene.
[0044] An example of a nonnucleophilic anion X- includes
FSO.sub.3.sup.-, an anion of an organic sulfonric acid or of a
carboxylic acid; or an anion LQ.sub.m.sup.-, as defined above. In
particular, an anion may be derived from a partially fluoro or
perfluoroaliphatic or a partially fluoro or a perfluoro aromatic
carboxylic acid, or in particular, from a partially fluoro or
perfluoroaliphatic or a partially fluoro or perfluoroaromatic
organic sulfonic acid, or is an anion LQ.sub.m.sup.-. A further
example of an anion X.sup.- includes BF.sub.4.sup.-,
PF.sub.6.sup.-, AsF.sub.6.sup.-, SbF.sub.6.sup.-,
SbF.sub.5(OH).sup.-, CF.sub.3SO.sub.3.sup.-,
C.sub.2F.sub.3SO.sub.3.sup.-, n-C.sub.3F.sub.7SO.sub.3.sup.-,
n-C.sub.4F.sub.9SO.sub.3.sup.-, n-C.sub.6F.sub.13SO.sub.3.sup.-,
n-C.sub.8F.sub.17SO.sub.3.sup.-, C.sub.6F.sub.5SO.sub.3.sup.-,
phosphorus tungstate, silicon tungstate, or any combination
thereof. In particular, an anion is PF.sub.6.sup.-,
AsF.sub.6.sup.-, SbF.sub.6.sup.-, CF.sub.3SO.sub.3.sup.-,
C.sub.2F.sub.3SO.sub.3.sup.-, n-C.sub.3F.sub.7SO.sub.3.sup.-,
n-C.sub.4F.sub.9SO.sub.3.sup.-, n-C.sub.6F.sub.13SO.sub.3.sup.-,
n-C.sub.8F.sub.17SO.sub.3.sup.-, or any combination thereof.
[0045] A metallocene salt can also be used in combination with an
oxidizing agent. Such a combination is described in published
European patent application EP 126712.
[0046] In a particular embodiment, the binder formulation includes
from about 0.1 wt % to about 20 wt %, such as about 0.2 wt % to
about 10 wt %, of cationic photoinitiator, based on the total
weight of the binder formulation.
[0047] To increase the light efficiency, or to sensitize the
cationic photoinitiator to specific wavelengths, such as for
example specific laser wavelengths or a specific series of laser
wavelengths, a sensitizer may be used, depending on the type of
initiator. An exemplary sensitizer includes a polycyclic aromatic
hydrocarbon, an aromatic keto compound, or any combination thereof.
A specific example of a sensitizer is mentioned in published
European patent application EP 153904. An exemplary sensitizer
includes benzoperylene, 1,8-diphenyl-1,3,5,7-octatetraene, or
1,6-diphenyl-1,3,5-hexatriene, as described in U.S. Pat. No.
5,667,937. An additional factor in the choice of sensitizer is the
nature and primary wavelength of the source of actinic
radiation.
[0048] In an embodiment, the binder formulation may include a
radically polymerizable constituent. For example, the binder
formulation may include a compound having at least one ethylenic
unsaturation which can be polymerized with radicals. An example of
a suitable ethylenic unsaturation is a group, such as acrylate,
methacrylate, styrene, vinylether, vinyl ester, N-substituted
acrylamide, N-vinyl amide functionalities, maleate ester, fumarate
ester, or any combination thereof. In particular embodiments, the
ethylenic unsaturation is provided by a group containing acrylate,
methacrylate, N-vinyl, or styrene functionality. For example, the
binder formulation may include one or more compounds having one or
more (meth)acrylate functionalities.
[0049] The free-radical polymerizable acrylic material that may be
used in the binder formulation has, on average, at least one
acrylic group which can be either the free acid or an ester. By
"acrylic" is meant the group--CH.dbd.CR1CO.sub.2R2, where R1 can be
hydrogen or methyl and R2 can be hydrogen or alkyl. By
"(meth)acrylate" is meant an acrylate, methacrylate, or any
combination thereof. An acrylic material typically undergoes a
polymerization or a crosslinking reaction initiated by a free
radical. The acrylic material can be a monomer, an oligomer, a
polymer, or any combination thereof. Typically, the acrylic
material is a monomer or an oligomer.
[0050] An acrylic constituent includes, for example, diacrylate of
cycloaliphatic or aromatic diol, such as
1,4-dihydroxymethylcyclohexane,
2,2-bis(4-hydroxycyclohexyl)propane, 1,4-cyclohexanedimethanol,
bis(4-hydroxycyclohexyl)methane, hydroquinone,
4,4-dihydroxybiphenyl, bisphenol A, bisphenol F, bisphenol S,
ethoxylated or propoxylated bisphenol A, ethoxylated or
propoxylated bisphenol F, or ethoxylated or propoxylated bisphenol
S, and any combination thereof.
[0051] A useful aromatic tri(meth)acrylate includes, for example, a
reaction product of triglycidyl ether of trihydric phenol, or
phenol or cresol novolac having three hydroxy groups with
(meth)acrylic acid. In a particular embodiment, the acrylic
material includes 1,4-dihydroxymethyl-cyclohexane diacrylate,
bisphenol A diacrylate, ethoxylated bisphenol A diacrylate, or any
combination thereof.
[0052] In a particular embodiment, the binder formulation may
include an acrylate of bisphenol A diepoxide, such as Ebecryl
3700.RTM. from UCB Chemical Corporation, Smyrna, Ga., a mixed
acrylate/epoxy compound of bisphenol A such as Ebecryl 3605.RTM.,
or an acrylate of 1,4-cyclohexanedimethanol.
[0053] In addition to or instead of the aromatic or cycloaliphatic
acrylic material, other acrylic materials can be useful. A
poly(meth)acrylate having functionality of greater than 2, where
appropriate, may be used in the binder formulation. Such a
poly(meth)acrylate can be, for example, a tri, tetra, or
pentafunctional monomeric or oligomeric aliphatic
(meth)acrylate.
[0054] A suitable aliphatic polyfunctional (meth)acrylate includes,
for example, a triacrylate or a trimethacrylate of
hexane-2,4,6-triol, glycerol, or 1,1,1-trimethylolpropane;
ethoxylated or propoxylated glycerol; or 1,1,1-trimethylolpropane
or a hydroxy group-containing tri(meth)acrylate which is obtained
by the reaction of triepoxy compound, such as, for example,
triglycidyl ether of the mentioned triol, with (meth)acrylic acid.
In addition, pentaerythritol tetra-acrylate, bistrimethylolpropane
tetra-acrylate, pentaerythritol monohydroxytri(meth)acrylate, or
dipentaerythritol monohydroxypenta(meth)acrylate, or any
combination thereof may be useful.
[0055] In another embodiment, hexafunctional urethane
(meth)acrylate is useful. Such urethane (meth)acrylate can be, for
example, prepared by reacting a hydroxy-terminated polyurethane
with acrylic acid or methacrylic acid, or by reacting an
isocyanate-terminated prepolymer with hydroxyalkyl (meth)acrylate
to follow the urethane (meth)acrylate. Also useful are an acrylate
or a methacrylate, such as tris(2-hydroxyethyl)isocyanurate
triacrylate.
[0056] Typically, the amount of radically polymerizable constituent
is, for example, between about 0.1 wt % and about 60 wt %, such as
between about 5 wt % and about 60 wt % or between about 10 wt % and
about 40 wt %.
[0057] The binder formulation may include a radical initiator, such
as a radical photoinitiator, especially in combination with
radically polymerizable constituent. A photoinitiator that forms
free radicals when irradiated can be used. Typical a photoinitiator
includes benzoin, such as benzoin; benzoin ether, such as benzoin
methyl ether, benzoin ethyl ether, or benzoin isopropyl ether;
benzoin phenyl ether; benzoin acetate; acetophenone, such as
acetophenone, 2,2-dimethoxyacetophenone,
4-(phenylthio)acetophenone, or 1,1-dichloroacetophenone; benzyl;
benzil ketal, such as benzil dimethyl ketal, or benzil diethyl
ketal; anthraquinones, such as 2-methylanthraquinone,
2-ethylanthraquinone, 2-tertbutylanthraquinone,
1-chloroanthraquinone, or 2-amylanthraquinone; triphenylphosphine;
benzoylphosphine oxides, such as, for example,
2,4,6-trimethylbenzoyidiph-enylphosphine oxide (Lucirin TPO);
benzophenone, such as benzophenone, or
4,4'-bis(N,N'-dimethylamino)benzophenone; thioxanthones or
xanthones; acridine derivative; phenazene derivative; quinoxaline
derivative; I-phenyl-1,2-propanedione-2-O-benzoyloxime;
I-aminophenyl ketones; I-hydroxyphenyl ketones, such as
I-hydroxycyclohexyl phenyl ketone, phenyl(1-hydroxyisopropyl)ketone
or 4-isopropylphenyl(1-hydroxy-isopropyl)ketone; triazine compound,
for example, 4'''-methyl
thiophenyl-1-di(trichloromethyl)-3,5-S-triazine,
S-triazine-2-(stilbene)-4,6-bistrichloromethyl or paramethoxy
styryl triazine, or any combination thereof.
[0058] A suitable free-radical photoinitiator alternatively
includes acetophenone, such as 2,2-dialkoxybenzophenone; a
1-hydroxyphenyl ketone, for example 1-hydroxycyclohexyl phenyl
ketone,
2-hydroxy-1-{4-(2-hydroxyethoxy)phenyl}-2-methyl-1-propanone, or
2-hydroxyisopropyl phenyl ketone (also called
2-hydroxy-2,2-dimethylaceto-phenone), or 1-hydroxycyclohexyl phenyl
ketone. Another class of free-radical photoinitiators comprises a
benzil ketal, such as, for example, benzil dimethyl ketal. An
alpha-hydroxyphenyl ketone, benzil dimethyl ketal, or
2,4,6-trimethylbenzoyldiphenylphosphine oxide is also useful as a
photoinitiator.
[0059] Another class of suitable free radical photoinitiators
includes an ionic dye-counter ion compound, which is capable of
absorbing actinic rays and producing free radicals that can
initiate the polymerization of an acrylate. As such, an ionic
dye-counter ion compound can thus cure using visible light in an
adjustable wavelength range of 400 to 700 nanometers. An additional
ionic dye-counter ion compound and its mode of action are, for
example, found in European patent application EP 223587 or U.S.
Pat. No. 4,751,102,4,772,530 or 4,772,541. A further example of an
ionic dye-counter ion compound includes an anionic dye-iodonium ion
complexe, an anionic dye-pyryllium ion complexe or a cationic
dye-borate anion compound of the following formula: ##STR3##
[0060] wherein D.sup.+ is a cationic dye and R12, R13, R14, and R15
are, each independently of the others, alkyl, aryl, alkaryl, allyl,
aralkyl, alkenyl, alkynyl, an alicyclic or saturated or unsaturated
heterocyclic group. An additional example of a radical R12 to R15
can be found, for example, in published European patent application
EP 223587.
[0061] In a particular embodiment, the binder formulation may
include about 0.01 wt % to about 20 wt % of free-radical
photoinitiator, such as about 0.01 wt % to about 15 wt % of
free-radical photoinitiator, based on the total weight of the
composition.
[0062] A hydroxyl-group containing material may be used in the
binder formulation. For example, the hydroxyl-group material may
include liquid organic material having a hydroxyl functionality of
at least 1, and preferably at least 2. The hydroxyl-group material
may be a liquid or a solid that is soluble or dispersible in the
remaining components. Typically, the material is substantially free
of a group that substantially slows down the curing reaction.
Often, the organic material contains two or more primary or
secondary aliphatic hydroxyl groups (i.e., the hydroxyl group is
bonded directly to a non-aromatic carbon atom). A monomer, an
oligomer, or a polymer can be useful. The hydroxyl equivalent
weight, i.e., the number average molecular weight divided by the
number of hydroxyl groups, is typically in the range of 31 to
5000.
[0063] A representative example of a suitable organic material
having a hydroxyl functionality of 1 includes alkanol, monoalkyl
ether of polyoxyalkyleneglycol, monoalkyl ether of alkyleneglycol,
or any combination thereof.
[0064] A representative example of a useful monomeric polyhydroxy
organic material includes alkylene and arylalkylene glycol or
polyol, such as 1,2,4-butanetriol, 1,2,6-hexanetriol,
1,2,3-heptanetriol, 2,6-dimethyl-1,2,6-hexanetriol,
(2R,3R)-(-)-2-benzyloxy-1,3,4-butanetriol, 1,2,3-hexanetriol,
1,2,3-butanetriol, 3-methyl-1,3,5-pentanetriol,
1,2,3-cyclohexanetriol, 1,3,5-cyclohexanetriol,
3,7,11,15-tetramethyl-1,2,3-hexadecanetriol,
2-hydroxymethyltetrahydropyran-3,4,5-triol,
2,2,4,4-tetramethyl-1,3-cyclobutanediol, 1,3-cyclopentanediol,
trans-1,2-cyclooctanediol, 1,16-hexadecanediol,
3,6-dithia-1,8-octanediol, 2-butyne-1,4-diol, 1,3-propanediol,
1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol,
1,8-octanediol, 1,9-nonanediol, 1-phenyl-1,2-ethanediol,
1,2-cyclohexanediol, 1,5-decalindiol,
2,5-dimethyl-3-hexyne-2,5-diol,
2,7-dimethyl-3,5-octadiyne-2-7-diol, 2,3-butanediol,
1,4-cyclohexanedimethanol, or any combination thereof.
[0065] A representative example of a useful oligomeric or polymeric
hydroxyl-containing material includes polyoxyethylene or
polyoxypropylene glycol or triol of molecular weights from about
200 to about 10,000; polytetramethylene glycol of various molecular
weights; copolymer containing pendant hydroxy groups formed by
hydrolysis or partial hydrolysis of a vinyl acetate copolymer,
polyvinylacetal resin containing pendant hydroxyl groups;
hydroxy-terminated polyester or hydroxy-terminated polylactone;
hydroxy-functionalized polyalkadiene, such as polybutadiene;
aliphatic polycarbonate polyol, such as an aliphatic polycarbonate
diol; hydroxy-terminated polyether, or any combination thereof.
[0066] A hydroxyl-containing monomer includes
1,4-cyclohexanedimethanol or aliphatic or cycloaliphatic
monohydroxy alkanol, or any combination thereof.
[0067] A typical hydroxyl-containing oligomer or polymer includes a
hydroxyl or a hydroxyl/epoxy functionalized polybutadiene,
1,4-cyclohexanedimethanol, polycaprolactone diol or triol,
ethylene/butylene polyol, monohydroxyl functional monomer, or any
combination thereof. An example of polyether polyol is
polypropylene glycol of various molecular weight or glycerol
propoxylate-B-ethoxylate triol. Another example includes a linear
or a branched polytetrahydrofuran polyether polyol available in
various molecular weights, such as for example 250, 650, 1000,
2000, and 2900 MW.
[0068] In a particular embodiment, the binder formulation may
include up to 60 wt % of polyol. For example, the binder
formulation may include about 0.1 wt % to about 60 wt % polyol,
such as between about 3 wt % and about 20 wt %.
[0069] The binder formulation includes a latent coloring component.
In a particular embodiment, the latent coloring component forms a
chromophore in response to curing of polymer constituent. In an
exemplary embodiment, the latent coloring component forms color or
changes color on contact with a photochemically generated
photoacid. In a particular embodiment, the latent coloring
component is a triaryl methane-, diphenyl methane-thiazine-,
spiro-, lactam-, fluoran or isobenzofuranone-based color former. An
example of triarylmethane-based color former includes
3-3-bis(p-dimethylaminophenyl)-6-dimethylaminophthalide,
3,3-bis(p-dimethylaminophenyl)phthalide,
3-(p-dimethylaminophenyl)-3-(1,2-dimethylindole-3-yl)phthalide,
3-(p-dimethylaminophenyl)-3-(2-methylindole-3-yl)phthalide,
3,3-bis(1,2-dimethylindole-3-yl)-5-dimethylaminophthalide,
3,3-bis(1,2-dimethylindole-3-yl)-6-dimethylaminophthalide,
3,3-bis(9-ethylcarbazole-3-yl)-6-dimethylaminophthalide,
3,3-bis(2-phenylindole-3-yl)-6-dimethylaminophthalide,
3-p-dimethylaminophenyl-3-(1-methylpyrrole-3-yl)-6-dimethylaminophthalide-
, etc., or triphenyl methane e.g., Crystal Violet Lactone, or any
combination thereof.
[0070] A typical diphenylmethane-based latent colorant component
includes 4,4'-bis-dimethylaminobenzhydryl benzyl ether,
N-halophenyl-leucoauramine, N-2,4,5-trichlorophenyl-leucoauramine,
or any combination thereof. An exemplary thiazine-based color
former includes benzoyl-leucomethylene blue,
p-nitrobenzoyl-leucomethylene blue, or any combination thereof. An
exemplary spiro-based color former includes
3-methyl-spiro-dinaphthopyran, 3-ethyl-spiro-dinaphthopyran,
3-phenyl-spirodinapthopyran, 3-benzyl-spiro-dinaphthopyran,
3-methyl-naphtho-(6'-methoxybenzo)spiropyran,
3-propyl-spiro-dibenzopyran, or any combination thereof. A
lactam-based color former includes rhodamine-b-anilinolactam,
rhodamine-(p-nitroanilino) lactam,
rhodamine-(o-chloroanilino)lactam, or any combination thereof. A
fluoran-based color former includes 3,6-dimethoxyfluoran,
3,6-diethoxyfluoran, 3,6-dibutoxyfluoran,
3-dimethylamino-7-methoxyfluoran,
3-dimethylamino-6-methoxylfluoran,
3-dimethylamino-7-methoxyfluoran, 3-diethylamino-7-chlorofluoran,
3-diethylamino-6-methyl-7-chlorofluoran,
3-diethylamino-6,7-dimethylfuoran,
3-(N-ethyl-p-toluidino)-7-methylfluoran,
3-diethylamino-7-(N-acetyl-N-methylamino)fluoran,
3-diethylamino-7-N-methylaminofluoran,
3-diethylamino-7-dibenzylaminofluoran,
3-diethylamino-5-methyl-7-dibenzylaminofluoran,
3-diethylamino-7-(N-methyl-N-benzylamino)fluoran,
3-diethylamino-7-(N-chl-oroethyl-N-methylamino)fluoran,
3-diethylamino-7-diethylaminofluoran,
3-(N-ethyl-p-toluidino)-6-methyl-7-phenylaminofluoran,
3-(N-ethyl-p-toluidino)-6-methyl-7-phenylaminofluoran,
3-diethylamino-7-(2-carbomethoxy-phenylamino)fluoran,
3-(N-ethyl-N-isoamylamino)-6-methyl-7-phenylaminofluoran,
3-(N-cyclohexyl-N-methylamino)-6-methyl-7-phenylaminofluoran,
3-pyrrolidino-6-methyl-7-phenylaminofluoran,
3-piperidino-6-methyl-7-phenylaminofluoran,
3-diethylamino-6-methyl-7-xylidinofluoran,
3-diethylamino-7-(o-chlorophenylamino)fluoran,
3-dibutylamino-7-(o-chloro-phenylamino)fluoran,
3-pyrrolidino-6-methyl-7-p-butylphenylaminofluoran, or any
combination thereof.
[0071] Latent colorant components permitting the production of a
wide range of colors are described, for example, by Peter Gregory
in High-Technology Applications of Organic Colourants, Plenum
Press, pages 124-134.
[0072] In particular, a latent coloring component includes an
isobenzofuranone-based color former or a color former that is
available under the tradenames of Copikem and Pergascript. An
example of such a coloring component inlcudes Copikem 20
(3,3-Bis(1-butyl-2-methyl-H-indol-3-yl)-1-(3H)-isobenzofuranone),
Copikem 5 (2'-Di
(phenylmethy)amino-6'-(diethylamino)spiro(isobenzofuran-1 (3H),
9'-(9H)xanthem)-3-one), Copikem 14 (a substituted phthalide),
Copikem 7
(3-{(4Dimethylamino)-phenyl}-3-(1-butyl-2methylindol-3yl)-6-dimethyamino)-
-1-(3H)-isobenzofuranone), Copikem 37
(2-(2-Octoxyphenyl)-4-(4-dimethylaminophenyl)-6-(phenyl)pyridine),
Pergascript Black I-R
(6''-(Dimethylamino)-3''-methyl-2''-(phenylamino)spiro-(isobenzofuran-1(3-
H), 9''(9H)xanthem-3-one), or Pergascript Color Former (like
diamiofluoran compound, bisaryl carbazolyl methane compound,
phthalide compound, bisindolyl phthalide compound, aminofluoran
compound, or quinazoline compound), or any combination thereof.
While the above examples are presented for illustrative purposes,
use of various other exemplary colorants can be envisaged based on
the disclosure herein.
[0073] In general, the latent colorant or latent coloring component
may react with or change color in response to byproducts or
chemical changes associated with curing of the binder formulation.
For example, the latent colorant may change color in response to
activation of a cationic photoinitiator. In another example, the
latent colorant may change color in response to a concentration of
photoacid. In a further example, the latent colorant may change
color in response to changes in concentration of monomeric
constituents, solvents, or byproducts of the polymerization of
monomers. In an additional example, the latent colorant may change
color in response to generation of cations or the concentration of
cations, in particular, cations, such as H.sup.+ cations, which may
be expressed as pH in particular binder formulations and
solvents.
[0074] In a particular embodiment, the binder formulation includes
between about 0.0001 wt % and about 2.0 wt %, such as about 0.0005
wt % to about 1.0 wt %, latent coloring component.
[0075] The binder formulation may also include a filler. In an
embodiment, an inorganic substance is used and provided for
water-resisting capabilities and mechanical properties. An example
of an inorganic filler includes silica, glass powder, alumina,
alumina hydrate, magnesium oxide, magnesium hydroxide, barium
sulfate, calcium sulfate, calcium carbonate, magnesium carbonate,
silicate mineral, diatomaceous earth, silica sand, silica powder,
titanium oxide, aluminum powder, bronze, zinc powder, copper
powder, lead powder, gold powder, silver dust, glass fiber, titanic
acid potassium whiskers, carbon whiskers, sapphire whiskers,
verification rear whiskers, boron carbide whiskers, silicon carbide
whiskers, silicon nitride whiskers, or any combination thereof.
[0076] The condition of the surface of the particles of the filler
used and the impurities contained in filler from the manufacturing
process can affect the curing reaction of the resin composition. In
such a case, the filler particles may be washed with an appropriate
primer.
[0077] The inorganic filler also may be surface-treated with a
silane coupling agent. An exemplary silane coupling agent includes
vinyl triclorosilane, vinyl tris(.beta.-methoxyethoxy) silane,
vinyltriethoxy silane, vinyltrimethoxy silane,
r-(methacryloxypropyl)trimethoxy silane,
.beta.-(3,4-epoxycyclohexyl)ethyltrimethoxy silane,
r-glycydoxypropyltrimethoxy silane, r-glycydoxypropylmethyl
diethoxy silane, N-.beta.-(aminoethyl)-r-aminopropyltrimethoxy
silane, N-.beta.-(aminoethyl)-.gamma.-aminopropylmethyldimethoxy
silane, r-aminopropyltriethoxysilane, N-phenyl-r-amino propyl
trimethoxy silane, r-mercaptopropyl trimethoxysilane, and
r-chloropropyltrimethoxy silane, or any combination thereof.
[0078] The above inorganic filler may be used singly or in
combination of two or more. In a particular embodiment, the binder
formulation includes about 0.01 wt % to about 95 wt % filler
relative to the total weight of the composition. For example, the
binder may include about 10 wt % to about 90 wt %, or about 20 wt %
to about 80 wt % filler.
[0079] In a further particular embodiment, the particulate filler
may be formed of inorganic particles, such as, for example, metals
(such as, for example, steel, Au or Ag) or a metal complex, such
as, for example, metal oxide, metal hydroxide, metal sulfide, metal
halogen complex, metal carbide, metal phosphate, inorganic salt
(like, for example, CaCO.sub.3), ceramics, or any combination
thereof. An example of a metal oxide includes ZnO, CdO, SiO.sub.2,
TiO.sub.2, ZrO.sub.2, CeO.sub.2, SnO.sub.2, MoO.sub.3, WO.sub.3,
Al.sub.2O.sub.3, In.sub.2O.sub.3, La.sub.2O.sub.3, Fe.sub.2O.sub.3,
CuO, Ta.sub.2O.sub.5, Sb.sub.2O.sub.3, Sb.sub.2O.sub.5, or any
combination thereof. A mixed oxide containing different metals may
also be present. The nanoparticle, for example, may comprise a
particle selected from the group consisting of ZnO, SiO.sub.2,
TiO.sub.2, ZrO.sub.2, SnO.sub.2, Al.sub.2O.sub.3, co-formed silica
alumina, or any combination thereof. The nanometer sized particle
may also have an organic component, such as, for example, carbon
black, highly crosslinked/core shell polymer nanoparticle, or an
organically modified nanometer-size particle, or any combination
thereof. Such a filler is described in, for example, U.S. Pat. No.
6,467,897 and WO 98/51747, hereby incorporated by reference.
[0080] Particulate filler formed via a solution-based processes,
such as sol-formed or a sol-gel formed ceramic, are particularly
well suited for use in the composite binder. A suitable sol is
commercially available. For example, a colloidal silica in aqueous
solution is commercially available under such trade designations as
"LUDOX" (E.I. DuPont de Nemours and Co., Inc. Wilmington, Del.),
"NYACOL" (Nyacol Co., Ashland, Ma.) or "NALCO" (Nalco Chemical Co.,
Oak Brook, Ill.). Many commercially available sols are basic, being
stabilized by alkali, such as sodium hydroxide, potassium
hydroxide, or ammonium hydroxide. An additional example of a
suitable colloidal silica is described in U.S. Pat. No. 5,126,394,
incorporated herein by reference. A well-suited particle includes
sol-formed silica and sol-formed alumina. The sol can be
functionalized by reacting one or more appropriate
surface-treatment agents with the inorganic oxide substrate
particle in the sol.
[0081] In a particular embodiment, the particulate filler is
sub-micron sized. For example, the particulate filler may be a
nano-sized particulate filler, such as a particulate filler having
an average particle size about 3 to 500 nm. In an exemplary
embodiment, the particulate filler has an average particle size
about 3 nm to about 200 nm, such as about 3 nm to about 100 nm,
about 3 nm to about 50 nm, about 8 nm to about 30 nm, or about 10
nm to about 25 nm. In a particular embodiment, the average particle
size is not greater than about 500 nm, such as not greater than
about 200 nm, less than about 100 nm, or not greater than about 50
nm. For the particulate filler, the average particle size may be
defined as the particle size corresponding to the peak volume
fraction in a small-angle neutron scattering (SANS) distribution
curve or the particle size corresponding to 0.5 cumulative volume
fraction of the SANS distribution curve.
[0082] The particulate filler may also be characterized by a narrow
distribution curve having a half-width not greater than about 2.0
times the average particle size. For example, the half-width may be
not greater than about 1.5 or not greater than about 1.0. The
half-width of the distribution is the width of the distribution
curve at half its maximum height, such as half of the particle
fraction at the distribution curve peak. In one particular
embodiment, the particle size distribution curve is mono-modal.
[0083] The particulate filler is generally dispersed in an external
phase. Prior to curing, the particulate filler is colloidally
dispersed within the binder formulation and forms a colloidal
composite binder once cured. For example, the particulate material
may be dispersed such that Brownian motion sustains the particulate
filler in suspension. In general, the particulate filler is
substantially free of particulate agglomerates. For example, the
particulate filler may be substantially mono-disperse such that the
particulate filler is dispersed as single particles, and in
particular examples, has only insignificant particulate
agglomeration, if any.
[0084] In a particular embodiment, the particles of the particulate
filler are substantially spherical. Alternatively, the particles
may have a primary aspect ratio greater than 1, such as at least
about 2, at least about 3, or at least about 6, wherein the primary
aspect ratio is the ratio of the longest dimension to the smallest
dimension. The particles may also be characterized by a secondary
aspect ratio defined as the ratio of orthogonal dimensions in a
plane generally perpendicular to the longest dimension. The
particles may be needle-shaped, such as having a primary aspect
ratio at least about 2 and a secondary aspect ratio not greater
than about 2, such as about 1. Alternatively, the particles may be
platelet-shaped, such as having a primary aspect ratio at least
about 2 and a secondary aspect ratio at least about 2.
[0085] In a particular embodiment, the particulate filler is
prepared in an aqueous solution and mixed with the external phase
of a suspension. The process for preparing such suspension includes
introducing an aqueous solution, such as an aqueous silica
solution; polycondensing the silicate, such as to a particle size
of 3 nm to 50 nm; adjusting the resulting silica sol to an alkaline
pH; optionally concentrating the sol; mixing the sol with
constituents of the external fluid phase of the suspension; and
optionally removing water or other solvent constituents from the
suspension. For example, an aqueous silicate solution is
introduced, such as an alkali metal silicate solution (e.g. a
sodium silicate or potassium silicate solution) with a
concentration in the range between 20% and 50% by weight based on
the weight of the solution. The silicate is then polycondensed to a
particle size of from 3 nm to 50 nm, for example, by treating the
alkali metal silicate solution with acidic ion exchangers. The
resulting silica sol is adjusted to an alkaline pH (e.g. pH>8)
to stabilized against further polycondensation or agglomeration of
existing particles. Optionally, the sol can be concentrated, for
example, by distillation, typically to SiO.sub.2 concentration of
about 30% to about 40% by weight. The sol is mixed with
constituents of the external fluid phase. Thereafter, water or
other solvent constituents are removed from the suspension. In a
particular embodiment, the suspension is substantially
water-free.
[0086] The fraction of the non-filler constituents in the pre-cured
binder formulation, generally including the organic polymeric
constituents, as a proportion of the binder formulation can be
about 20% to about 95% by weight, for example, about 30% to about
95% by weight, and typically from about 50% to about 95% by weight,
and even more typically from about 55% to about 80% by weight. The
fraction of the dispersed particulate filler phase can be about 5%
to about 80% by weight, for example, about 5% to about 70% by
weight, typically from about 5% to about 50% by weight, and more
typically from about 20% to about 45% by weight. The colloidally
dispersed and submicron particulate fillers described above are
particularly useful in concentrations at least about 5 wt %, such
as at least about 10 wt %, at least about 15 wt %, at least about
20 wt %, or as great as 40 wt % or higher. In contrast with
traditional fillers, the solution formed nanocomposites exhibit low
viscosity and improved processing characteristics at higher
loading. The amounts of components are expressed as weight % of the
component relative to the total weight of the composite binder
formulation, unless explicitly stated otherwise.
[0087] The binder formulation including an external phase
comprising polymeric or monomeric constituents and optionally
including dispersed particulate filler may be used to form a make
coat, size coat, compliant coat, or back coat of a coated abrasive
article. In a exemplary process for forming a make coat, the binder
formulation is coated on a backing, abrasive grains are applied
over the make coat, and the make coat is cured. A size coat may be
applied over the make coat and abrasive grains. In another
exemplary embodiment, the binder formulation is blended with the
abrasive grains to form abrasive slurry that is coated on a backing
and cured. Alternatively, the abrasive slurry is applied to a mold,
such as injected into a mold and cured to form a bonded abrasive
article.
[0088] The abrasive grains may be formed of any one of or a
combination of abrasive grains, including silica, alumina (fused or
sintered), zirconia, zirconia/alumina oxide, silicon carbide,
garnet, diamond, cubic boron nitride, silicon nitride, ceria,
titanium dioxide, titanium diboride, boron carbide, tin oxide,
tungsten carbide, titanium carbide, iron oxide, chromia, flint,
emery, or any combination thereof. For example, the abrasive grains
may be selected from a group consisting of silica, alumina,
zirconia, silicon carbide, silicon nitride, boron nitride, garnet,
diamond, cofused alumina zirconia, ceria, titanium diboride, boron
carbide, flint, emery, alumina nitride, or a blend thereof.
Particular embodiments have been created by use of dense abrasive
grains comprised principally of alpha-alumina.
[0089] The abrasive grain may also have a particular shape.
Examples of such shapes include rods, triangles, pyramids, cones,
solid spheres, hollow spheres and the like. Alternatively, the
abrasive grain may be randomly shaped.
[0090] The abrasive grains generally have an average grain size not
greater than 2000 microns, such as not greater than about 1500
microns. In another example, the abrasive grain size is not greater
than about 750 microns, such as not greater than about 350 microns.
For example, the abrasive grain size may be at least 0.1 microns,
such as from about 0.1 microns to about 1500 micron, and more
typically from about 0.1 microns to about 200 microns or from about
1 micron to about 100 microns. The grain size of the abrasive
grains is typically specified to be the longest dimension of the
abrasive grain. Generally, there is a range distribution of grain
sizes. In some instances, the grain size distribution is tightly
controlled.
[0091] In a blended abrasive slurry including the abrasive grains
and the binder formulation, the abrasive grains provide from about
10% to about 90%, such as from about 30% to about 80%, of the
weight of the abrasive slurry.
[0092] The abrasive slurry may further include a grinding aid to
increase the grinding efficiency and cut rate. Useful grinding aids
can be inorganic based, such as halide salts, for example sodium
cryolite, potassium tetrafluoroborate, etc.; or organic based, such
as chlorinated waxes, for example, polyvinyl chloride. A particular
embodiment includes cryolite and potassium tetrafluoroborate with
particle size ranging from 1 micron to 80 microns, and most
typically from 5 microns to 30 microns. The weight percent of
grinding aid ranges is generally not greater than about 50 wt %,
such as from about 0 wt % to about 50 wt %, and most typically from
about 10 wt % to about 30 wt % of the entire slurry (including the
abrasive grains).
[0093] FIG. 1 illustrates an exemplary embodiment of a coated
abrasive article 100, which includes abrasive grains 106 secured to
a backing or support member 102. Generally, the abrasive grains 106
are secured to the backing 102 by a make coat 104. The make coat
104 includes a binder, which is typically formed of a cured binder
formulation including latent colorant. When the binder formulation
is cured the latent colorant reacts to form reaction activated
chromophores that impart color to the binder or change the color of
the binder.
[0094] The coated abrasive article 100 may further include a size
coat 108 overlying the make coat 104 and the abrasive grains 106.
The size coat 108 generally functions to further secure the
abrasive grains 106 to the backing 102 and may also provide
grinding aids. The size coat 108 is generally formed from a cured
binder formulation that may be the same or different from the make
coat binder formulation and may include a second latent
colorant.
[0095] The coated abrasive 100 may also, optionally, include a back
coat 112. The back coat 112 functions as an anti-static layer,
preventing abrasive grains from adhering to the back side of the
backing 102 and preventing swarf from accumulating charge during
sanding. In another example, the back coat 112 may provide
additional strength to the backing 102 and may act to protect the
backing 102 from environmental exposure. In another example, the
back coat 112 can also act as a compliant layer. The compliant
layer may act to relieve stress between the make coat 104 and the
backing 102.
[0096] The backing may be flexible or rigid. The backing may be
made of any number of various materials including those
conventionally used as backings in the manufacture of coated
abrasives. An exemplary flexible backing includes a polymeric film
(including primed film), such as polyolefin film (e.g.,
polypropylene including biaxially oriented polypropylene),
polyester film (e.g., polyethylene terephthalate), polyamide film,
cellulose ester film, metal foil, mesh, foam (e.g., natural sponge
material or polyurethane foam), cloth (e.g., cloth made from fibers
or yarns comprising polyester, nylon, silk, cotton, poly-cotton or
rayon), paper, vulcanized paper, vulcanized rubber, vulcanized
fiber, nonwoven materials, any combination thereof, or any treated
version thereof. A cloth backing may be woven or stitch bonded. In
a particular example, the backing is selected from a group
consisting of paper, polymer film, cloth, cotton, poly-cotton,
rayon, polyester, poly-nylon, vulcanized rubber, vulcanized fiber,
metal foil, or any combination thereof. In another example, the
backing includes polypropylene film or polyethylene terephthalate
(PET) film.
[0097] The backing may, optionally, have at least one of a
saturant, a presize layer or a backsize layer. The purpose of these
layers is typically to seal the backing or to protect yarn or
fibers in the backing. If the backing is a cloth material, at least
one of these layers is typically used. The addition of the presize
layer or backsize layer may additionally result in a "smoother"
surface on either the front or the back side of the backing. Other
optional layers known in the art may also be used (e.g., tie layer;
see, e.g., U.S. Pat. No. 5,700,302 (Stoetzel et al.), the
disclosure of which is incorporated by reference).
[0098] An antistatic material may be included in any of the above
cloth treatment materials. The addition of an antistatic material
can reduce the tendency of the coated abrasive article to
accumulate static electricity when sanding wood or wood-like
material. Additional details regarding antistatic backings and
backing treatments can be found in, for example, U.S. Pat. No.
5,108,463 (Buchanan et al.); U.S. Pat. No. 5,137,542 (Buchanan et
al.); U.S. Pat. No. 5,328,716 (Buchanan); and U.S. Pat. No.
5,560,753 (Buchanan et al.), the disclosures of which are
incorporated herein by reference.
[0099] The backing may be a fibrous reinforced thermoplastic, such
as described, for example, in U.S. Pat. No. 5,417,726 (Stout et
al.), or an endless spliceless belt, as described, for example, in
U.S. Pat. No. 5,573,619 (Benedict et al.), the disclosures of which
are incorporated herein by reference. Likewise, the backing may be
a polymeric substrate having hooking stems projecting therefrom,
such as that described, for example, in U.S. Pat. No. 5,505,747
(Chesley et al.), the disclosure of which is incorporated herein by
reference. Similarly, the backing may be a loop fabric, such as
that described, for example, in U.S. Pat. No. 5,565,011 (Follett et
al.), the disclosure of which is incorporated herein by
reference.
[0100] In some examples, a pressure-sensitive adhesive is
incorporated onto the back side of the coated abrasive article such
that the resulting coated abrasive article can be secured to a pad.
Exemplary pressure-sensitive adhesives include latex crepe, rosin,
acrylic polymer or copolymer, including polyacrylate ester (e.g.,
poly(butyl acrylate)), vinyl ether (e.g., poly(vinyl n-butyl
ether)), alkyd adhesive, rubber adhesives (e.g., natural rubber,
synthetic rubber, chlorinated rubber), or any mixture thereof.
[0101] An exemplary rigid backing includes a metal plate, a ceramic
plate, or the like. Another example of a suitable rigid backing is
described, for example, in U.S. Pat. No. 5,417,726 (Stout et al.),
the disclosure of which is incorporated herein by reference.
[0102] A coated abrasive article, such as the coated abrasive
article 100 of FIG. 1, may be formed by coating a backing with a
binder formulation or abrasive slurry. Optionally, the backing may
be coated with a compliant coat or back coat prior to coating with
the make coat. Typically, the binder formulation is applied to the
backing to form the make coat. In an embodiment, abrasive grains
are applied with the binder formulation, wherein the abrasive
grains are blended with the binder formulation to form abrasive
slurry prior to application to the backing. Alternatively, the
binder formulation is applied to the backing to form the make coat
and the abrasive grains are applied to the make coat, such as
through electrostatic and pneumatic methods. The binder formulation
is cured such as through thermal methods or exposure to actinic
radiation, causing a color change in the latent colorant.
[0103] Optionally, a size coat is applied over the make coat and
abrasive grains. The size coat may be applied prior to curing the
make coat, the make coat and size coat being cured simultaneously.
Alternatively, the make coat is cured prior to application of the
size coat and the size coat is cured separately. Latent colorants
in the size coat may change color during curing.
[0104] The binder formulation forming the make coat, the size coat,
the compliant coat or the back coat may include colloidal binder
formulation. The colloidal binder formulation may include
sub-micron particulate filler, such as nano-sized particulate
filler having a narrow particle size distribution. In a particular
embodiment, the colloidal binder formulation is cured to form the
size coat. In another embodiment, the colloidal binder formulation
is cured to form the make coat. Alternatively, the colloidal binder
formulation may be cured to form the optional compliant coat or the
optional back coat.
[0105] In a particular embodiment, the coats and abrasive grains
may be patterned to form structures. For example, the make coat may
be patterned to form surface structures that enhance abrasive
article performance. Patterns may be pressed or rolled into the
coats using, for example, a rotogravure apparatus to form a
structured or engineered abrasive article.
[0106] An exemplary embodiment of an engineered or structured
abrasive is illustrated in FIG. 2. The structured abrasive includes
a backing 202 and a layer 204 including abrasive grains. The
backing 202 may be formed of the materials described above in
relation to the backing 102 of FIG. 1. Generally, the layer 204 is
patterned to have surface structures 206.
[0107] The layer 204 may be formed as one or more coats. For
example, the layer 204 may include a make coat and optionally, a
size coat. The layer 204 generally includes abrasive grains and a
binder. In one exemplary embodiment, the abrasive grains are
blended with a binder formulation to form an abrasive slurry.
Alternatively, the abrasive grains are applied to the binder after
the binder is coated on the backing 202. Optionally, a functional
powder may be applied over the layer 204 to prevent the layer 204
from sticking to the patterning tooling. The binder of the make
coat or the size coat may include latent colorant. The structured
abrasive article 200 optionally may include compliant and back
coats (not shown). These coats may function as described above.
[0108] In a further example, a binder formulation including latent
colorant may be used to form bonded abrasive articles, such as the
abrasive article 300 illustrated in FIG. 3. In a particular
embodiment, binder formulation and abrasive grains are blended to
form abrasive slurry. The abrasive slurry is applied to a mold and
the binder formulation is cured, causing a change in color of the
latent colorant. The resulting abrasive article, such as article
300, includes the abrasive grains bound by nano-composite binder in
a desired shape.
[0109] In a particular embodiment, the abrasive article is formed
by blending nanocomposite precursors with other polymeric
precursors and constituents. For example, a nanocomposite epoxy
precursor, including nano-sized particulate filler and epoxy
precursor, is mixed with acrylic precursor to form a nanocomposite
binder formulation. The binder formulation is applied to a
substrate, such as a backing or to a mold. Abrasive grains are also
applied to the substrate and the binder formulation is cured.
[0110] When the nanocomposite binder forms a make coat for a coated
abrasive article, the nanocomposite binder formulation may be
applied to a backing and abrasive grains applied over the
formulation. Alternatively, the binder formulation may be applied
over the abrasive grains to form a size coat. In another example,
the binder formulation and the abrasive grains may be blended and
applied simultaneously to form a make coat over a substrate or to
fill a mold. Generally, the binder formulation may be cured using
thermal energy or actinic radiation, such as ultraviolet
radiation.
[0111] In a particular embodiment, the binder formulation includes
an epoxy constituent, a cationic photoinitiator within the epoxy
constituent, and a latent colorant configured to change color in
response to activation of the cationic photoiniator. The binder
formulation may include about 10 wt % to about 90 wt %, such as
about 65 wt % to about 80 wt %, of the epoxy constituent and may
include about 0.1 wt % to about 20 wt %, such as about 0.1 wt % to
about 4.0 wt %, of the cationic photoinitiator. The epoxy
constituent may include nano-sized particulate filler, such as
filler having particle size not greater than about 100 nm, such as
not greater than about 50 nm.
[0112] The binder formulation may include an acrylic constituent
and a radical generating photoinitiator. The binder formulation may
include about 0.1 wt % to about 60 wt %, such as about 5 wt % to
about 15 wt %, of the acrylic constituent and may include about
0.01 wt % to about 20 wt %, such as about 0.1 wt % to about 4 wt %,
radical generating photoinitiator. The acrylic constituent may
include nano-sized particulate filler, such as filler having
particle size not greater than about 100 nm, such as not greater
than about 50 nm. The binder formulation may also include a polyol
constituent in an amount of about 0.1 wt % to about 60 wt %, such
as about 10 wt % to about 17 wt %.
[0113] The latent colorant may exhibit a specific color based on
curing of the epoxy constituent. In an example, the latent colorant
reacts with byproducts of the cationic photoinitiator to change
color. The binder formulation may include one or more colorants.
For example, the binder formulation may further include a second
latent colorant. The second latent colorant may change to a second
color based on the curing. In another example, the second colorant
changes color in response to a different reaction, such as
activation of a radical generating photoinitiator.
[0114] In an exemplary embodiment, the latent colorant and the
second latent colorant may together change to appear as a desirable
color. For example, a first reaction activated chromophore
associated with the first latent colorant may have a first
electromagnetic energy absorption profile and a second reaction
activated chromophore associated with the second latent colorant
may have a second electromagnetic energy absorption profile. In an
example, the first electromagnetic energy absorption profile is
different from the second electromagnetic energy absorption
profile. In a further example, the first electromagnetic energy
absorption profile and the second electromagnetic energy absorption
profile appear as a desired color.
[0115] In an alternative embodiment, a latent colorant may be
selected for addition to a binder formulation to provide color
coding of binder formulations. For example, a first binder
formulation may include a first latent colorant and a second binder
formulation may include a second latent colorant. In such an
embodiment, the color of a cured abrasive product may aid in
identifying the binder formulation used to form the cured abrasive
product. In a further example, each coat, such as a make coat or a
size coat, may be formed from a different binder formulation and
each of the different binder formulations may include a different
latent colorant.
[0116] The binder formulation may be cured to form an abrasive
product, such as a layer of a coated abrasive product. Latent
colorants become chromophores through reactions associated with
curing of the polymer components. Generally, the latent colorants
and chromophores are organic, not to be confused with inorganic
pigments. Typically, the binder formulation and resulting abrasive
product are free of particulate pigment. In some examples,
particulate pigment can interfere with curing through actinic
radiation, causing defects in resulting abrasive products.
[0117] In another embodiment, the disclosure is directed to a
method of manufacturing an abrasive article. The method includes
initiating a curing process on a workpiece, determining a target
color exhibited by the workpiece, and terminating the curing
process based on the target color. The target color may represent
partial curing or full curing. The curing process may include photo
curing or thermal curing. In an example, a make coat is applied to
the abrasive article workpiece prior to curing. In another example,
an uncured size coat is applied to the workpiece prior to curing.
In a further example, a mold is filled to form the workpiece. A
second curing process may be initiated after terminating the curing
process, a second target color may be determined and the second
curing process terminated based on the second target color.
[0118] In a further exemplary embodiment, the disclosure is
directed to a method of controlling abrasive product quality. The
method includes forming an abrasive product having a polymer matrix
and a reaction activated chromophore, inspecting the abrasive
product for a color characteristic, and categorizing the abrasive
product based on the color characteristic. The color characteristic
may, for example, be a target color or color uniformity.
Categorizing the abrasive product may include rejecting the
abrasive product, accepting the abrasive product or grading the
abrasive product. Grades may be associated with abrasive product
usage conditions. The product may be further cured after
categorizing.
[0119] Measurement of color can be performed with a chromameter.
When the resin composition is opaque, for example, due to the
presence of a filler, the color of the resin and the article is
measured with a chromameter on the article or resin. In an example,
a chromameter provides three values in the L*a*b color scale
(CIELAB). The CIELAB color scale is an approximate uniform color
scale. In a uniform color scale, the differences between points
plotted in the color space correspond to visual differences between
the colors plotted. The CIELAB color space is organized in a cube
form. The L* axis runs from the top to bottom. The maximum L* is
100, which represents a reflecting diffuser. The minimum L* is
zero, which represents black. The a* and b* axis have no specific
numerical limit. Positive a* is typically red and negative a* is
typically green. Positive b* is generally yellow and negative b* is
generally blue. For example, when a* is -60, it represents green
and when a* is +60, it represents red. The b* represents blue when
it is -60 and yellow when it is +60. Articles having a* and b*
value between -20 and 20 typically have a grey appearance. Articles
having a* and b* values between -20 and -60 or between 20 and 60
are generally more colorful.
[0120] Typically, conventional resin compositions with and without
fillers but without latent colorant exhibit large L* values of
between 90 and 100. In contrast, embodiments of articles, for
example, formed by UV-curing of a resin including latent colorant
exhibit a different color than the uncured resin. Such a color may
be expressed as a change in L* value, a* value, or b* value
relative to the resin. In an example, the L* value may change at
least about 10 units, such as at least about 20 units. Typically,
the a* or b* values of an article change by at least about 10 units
after cure of the resin. For instance, the a* or b* value may
change by at least about 20 units. In an exemplary embodiment, the
L* value may not change substantially, but the color may change,
for example, from red to blue. In such an embodiment, the a* or b*
value may change at least about 20 units, such as at least about 30
units. In another embodiment, the L* value of the article changes
relative to the resin, so that cured articles have L* values of
between 0 and 85, such as between 20 and 75. In an example, the a*
or b* value of the cured articles may stay the same as the values
of the resin when the L* value changes.
[0121] In a particular embodiment, the L* value of a binder
formulation or an abrasive article workpiece may change by at least
about 10%, such as at least about 20% or at least about 30%. In
another example, the a* value or the b* value may change by at
least about 10%, such as at least about 20% or at least about 30%.
When determining a target color, the method may include determining
a target L* value or a change in L* value. Alternatively, the
method may include determining a target a* value or a target b*
value or changes in the a* value or the b* value.
EXAMPLE 1
[0122] An example binder formulation includes: TABLE-US-00001
INGREDIENT Wt. % Description Nanopox XP 22/0314 72.02 Epoxy
4,8-bis(hydroxymethyl) 14.40 Polyol tricyclo[5.2.1.0)decane
Chivacure 184 0.48 Photoinitiator Chivacure 1176 2.88
Photoinitiator Nanocryl XP 21/0954 9.60 Acrylate Specialty Blue 1
0.40 additive BYK A-501 0.02 additive Silwet L 7600 0.20 additive
Totals: 100.00
EXAMPLE 2
[0123] Sample binder formulations are prepared and cured. The color
of the cured samples are tested using a HunterLab Color Quest XE
chromameter in reflectance test mode with a D65 illuminant and at
an angle of 10.degree.. The color of the samples is represented in
the CIELAB color scale. A white backing medium is used during
measurement.
[0124] Effect of dye concentration on binder color is determined by
testing binder formulations in a standardized abrasive article
configuration (4 inch length and 10 inch width). The binder
formulations at different dye concentrations are used as a size
coat over abrasive grains and a make coat. Film samples that have
size coatings at different dye concentration are UV cured at 300 W
D bulb/600 W H bulb at a line speed 50 feet/minute. The abrasive
grains are 80 micron heat-treated semi-friable aluminum oxide from
Treibacher (BFRPL) P180 grit and the make coat is formed of
UV-curable epoxy/acrylate resins. The abrasive grains and make coat
overlie a polyester backing. The effect of dye concentration on the
value L*, a*, b* is determined. Size coats on sample abrasive
articles are formed from binder formulations including Nanopox XP
A610 available from Hanse Chemie, an epoxy resin including
3,4-epoxy cyclohexyl methyl-3,4-epoxy cyclohexyl carboxylate and 40
wt % colloidal silica particulate filler. The binder formulations
also include UVR 6105, which includes 3,4-epoxy cyclohexyl
methyl-3,4-epoxy cyclohexyl carboxylate and no particulate filler.
The binder formulations further include a polyol
(4,8-bis(hydroxymethyl) tricyclo(5.2.1.0)decane), a cationic
photoinitiator (Chivacure 1176), a radical photoinitiator (Irgacure
2022, available from Ciba.RTM.), acrylate precursor (SR 399, a
dipentaerythritol pentaacrylate available from Atofina-Sartomer,
Exton, Pa.), and dye (specialty blue 1, available from Noveon
Hilton Davis, Inc., 2235 Langdon Farms Rd., Cincinnati, Ohio
45237-4790).
[0125] Table 1 illustrates the concentration of components in the
binder formulations and the resulting value of L*, a*, and b*.
Generally, increasing the concentration of Specialty Blue 1 dye
causes a reduction in L* for the cured binder formulation. In
addition, b* changes in a negative direction with increasing
Specialty Blue 1 dye in the binder formulation. TABLE-US-00002
TABLE 1 INGREDIENT A B C D Nanopox A610 60.00 60.00 60.00 60.00 UVR
6105 19.92 19.92 19.92 19.92 4,8-bis(hydroxymethyl) 13.50 13.50
13.50 13.50 tricyclo(5.2.1.0)decane Irgacure 2022 0.48 0.48 0.48
0.48 Chivacure 1176 1.50 1.50 1.50 1.50 SR 399 4.60 4.60 4.60 4.60
Specialty Blue 1 0 0.1 0.2 0.4 L* 72.05 61.61 52.61 44.58 a* -0.76
-7.52 -7.75 -2.36 b* 4.16 -10.96 -22.19 -30.11
[0126] Exemplary embodiments of the above described binder
formulations and abrasive articles formed from the binder
formulation may advantageously be useful in quality control, end
product coloration, characterization of the product, and process
control. Absence of particulate pigments advantageously leads to
improved curing for actinic radiation curable binder
formulations.
[0127] The above-disclosed subject matter is to be considered
illustrative, and not restrictive, and the appended claims are
intended to cover all such modifications, enhancements, and other
embodiments, which fall within the true scope of the present
invention. Thus, to the maximum extent allowed by law, the scope of
the present invention is to be determined by the broadest
permissible interpretation of the following claims and their
equivalents, and shall not be restricted or limited by the
foregoing detailed description.
* * * * *