U.S. patent application number 13/906687 was filed with the patent office on 2014-06-26 for curable silsesquioxane polymers, compositions, articles, and methods.
The applicant listed for this patent is 3M INNOVATIVE PROPERTIES COMPANY. Invention is credited to Jitendra S. Rathore.
Application Number | 20140178698 13/906687 |
Document ID | / |
Family ID | 50974977 |
Filed Date | 2014-06-26 |
United States Patent
Application |
20140178698 |
Kind Code |
A1 |
Rathore; Jitendra S. |
June 26, 2014 |
CURABLE SILSESQUIOXANE POLYMERS, COMPOSITIONS, ARTICLES, AND
METHODS
Abstract
A curable silsesquioxane polymer, a composition including such
polymer, an article having a layer disposed thereon that includes
the curable polymer and/or the cured polymer, and a method of
forming a cured coating, wherein the curable silsesquioxane polymer
includes a three-dimensional branched network having the formula:
##STR00001## wherein: the oxygen atom at the * is bonded to another
Si atom within the three-dimensional branched network; R is an
organic group comprising an ethylenically unsaturated group; n is
an integer of greater than 3; and the --OH groups are present in an
amount of at least 15 wt-% of the polymer.
Inventors: |
Rathore; Jitendra S.;
(Woodbury, MN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
3M INNOVATIVE PROPERTIES COMPANY |
St. Paul |
MN |
US |
|
|
Family ID: |
50974977 |
Appl. No.: |
13/906687 |
Filed: |
May 31, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61740590 |
Dec 21, 2012 |
|
|
|
Current U.S.
Class: |
428/447 ;
427/515; 522/18; 522/33; 526/279; 528/10 |
Current CPC
Class: |
C09D 183/04 20130101;
C08G 77/20 20130101; C08L 2312/08 20130101; C08G 77/04 20130101;
Y10T 428/31663 20150401 |
Class at
Publication: |
428/447 ;
526/279; 528/10; 522/33; 522/18; 427/515 |
International
Class: |
C09D 183/04 20060101
C09D183/04; C08G 77/04 20060101 C08G077/04; C09D 143/04 20060101
C09D143/04; C08F 30/08 20060101 C08F030/08 |
Claims
1. A curable silsesquioxane polymer comprising a three-dimensional
branched network having the formula: ##STR00009## wherein: the
oxygen atom at the * is bonded to another Si atom within the
three-dimensional branched network; R is an organic group
comprising an ethylenically unsaturated group; n is an integer of
greater than 3; and the --OH groups are present in an amount of at
least 15 wt-% of the polymer.
2. The curable silsesquioxane polymer of claim 1 wherein the --OH
groups are present in an amount of no greater than 60 wt-% of the
polymer.
3. The curable silsesquioxane polymer of claim 1 wherein n is an
integer of no greater than 100.
4. The curable silsesquioxane polymer of claim 1 wherein R has the
formula --Y--Z, wherein Y is a bond, an alkylene group, an arylene
group, or a combination thereof, and Z is an ethylenically
unsaturated group selected from a vinyl group, a vinylether group,
a (meth)acryloyloxy group, and a (meth)acryloylamino group.
5. The curable silsesquioxane polymer of claim 4 wherein Y is a
bond, a (C1-C20)alkylene group, a (C6-C12)arylene group, a
(C6-C12)alk(C1-C20)arylene group, a (C6-C12)ar(C1-C20)alkylene
group, or a combination thereof.
6. The curable silsesquioxane polymer of claim 1 which has peel
force from glass of at least 1 N/dm.
7. A curable silsesquioxane polymer comprising a three-dimensional
branched network which is a condensation reaction product of a
compound having the formula Z--Y--Si(R.sup.1).sub.3, wherein: Y is
a bond, an alkylene group, an arylene group, or a combination
thereof; Z is an ethylenically unsaturated group selected from a
vinyl group, a vinylether group, a (meth)acryloyloxy group, and a
(meth)acryloylamino group; and each R.sup.1 group is independently
a hydrolyzable group; wherein the polymer includes --OH groups in
an amount of at least 15 wt-% of the polymer.
8. The curable silsesquioxane polymer of claim 7 wherein Y is a
bond, a (C1-C20)alkylene group, a (C6-C12)arylene group, a
(C6-C12)alk(C1-C20)arylene group, a (C6-C12)ar(C1-C20)alkylene
group, or a combination thereof.
9. A curable composition comprising a photoinitiator and the
curable silsesquioxane polymer of claim 1.
10. The curable composition of claim 9 wherein the photoinitiator
is a free-radical photoinitiator.
11. The curable composition of claim 9 further comprising
nanoparticles.
12. The curable composition of claim 9 further comprising an
organic solvent.
13. An article comprising a substrate and the curable composition
of claim 9 in a layer disposed on at least a portion of at least
one surface of the substrate.
14. An article comprising a substrate and a cured coating layer
prepared by UV curing the composition of claim 9 disposed on at
least a portion of at least one surface of the substrate.
15. A method of making a cured coating on a substrate surface, the
method comprising: coating a curable composition of claim 9 on at
least a portion of at least one substrate surface; optionally
exposing the coated curable composition to conditions that allow an
organic solvent, if present, to evaporate from the curable
composition; and UV curing the curable composition.
Description
BACKGROUND
[0001] Hard coatings can generally be defined as clear coatings
that provide protection against abrasion and scratch when applied
to relatively softer substrates. In addition to the abrasion and
scratch-resistance, excellent durability is also desired. In
general, hard-coats can be prepared by mixing silica nanoparticles
with a base polymer, for example, an epoxy- or acrylate-based
polymer. The major drawback for some epoxy- or acrylate-based
coatings is poor outdoor weatherability. Thus, new polymers are
needed that have better outdoor weatherability and that can be used
to prepare hard coats.
SUMMARY
[0002] The present disclosure provides a curable silsesquioxane
polymer, a composition including such polymer, an article having a
layer disposed thereon that includes the curable polymer and/or the
cured polymer, and a method of forming a cured coating. Such
silsesquioxane (SSQ) polymers can have excellent outdoor
weatherability, as well as desirable UV and moisture resistance
properties.
[0003] In one embodiment, the present disclosure provides a curable
silsesquioxane polymer that includes a three-dimensional branched
network having the formula:
##STR00002##
wherein: the oxygen atom at the * is bonded to another Si atom
within the three-dimensional branched network; R is an organic
group comprising an ethylenically unsaturated group; n is an
integer of greater than 3; and the --OH groups are present in an
amount of at least 15 wt-% of the polymer.
[0004] In one embodiment, the present disclosure provides a curable
silsesquioxane polymer that includes a three-dimensional branched
network which is a condensation reaction product of a compound
having the formula Z--Y--Si(R.sup.1).sub.3, wherein: Y is a bond,
an alkylene group, an arylene group, or a combination thereof; Z is
an ethylenically unsaturated group selected from a vinyl group, a
vinylether group, a (meth)acryloyloxy group, and a
(meth)acryloylamino group; and each R.sup.1 group is independently
a hydrolyzable group; wherein the polymer includes --OH groups in
an amount of at least 15 wt-% of the polymer.
[0005] In one embodiment, the present disclosure provides a curable
composition that includes a photoinitiator (e.g., a free-radical
initiator) and a curable silsesquioxane polymer of the present
disclosure. In certain embodiments, the curable composition can
optionally include nanoparticles. In certain embodiments, the
curable composition can optionally include an organic solvent.
[0006] In one embodiment, the present disclosure provides an
article that includes a substrate and a curable composition of the
present disclosure in a layer disposed on at least a portion of at
least one surface of the substrate.
[0007] In one embodiment, the present disclosure provides an
article that includes a substrate and a cured coating layer
prepared by UV curing a curable composition of the present
disclosure disposed on at least a portion of at least one surface
of the substrate.
[0008] In one embodiment, the present disclosure provides a method
of making a cured coating on a substrate surface. The method
includes: coating a curable composition of the present disclosure
on at least a portion of at least one substrate surface; optionally
exposing the coated curable composition to conditions that allow an
organic solvent, if present, to evaporate from the curable
composition; and UV curing the curable composition.
[0009] As used herein, the term "organic group" means a hydrocarbon
group (with optional elements other than carbon and hydrogen, such
as oxygen, nitrogen, sulfur, silicon, and halogens) that is
classified as an aliphatic group, cyclic group, or combination of
aliphatic and cyclic groups (e.g., alkaryl and aralkyl groups). In
the context of the present invention, the organic groups are those
that do not interfere with the formation of curable silsesquioxane
polymer. The term "aliphatic group" means a saturated or
unsaturated linear or branched hydrocarbon group. This term is used
to encompass alkyl, alkenyl, and alkynyl groups, for example. The
term "alkyl group" is defined herein below. The term "alkenyl
group" means an unsaturated, linear or branched hydrocarbon group
with one or more carbon-carbon double bonds, such as a vinyl group.
The term "alkynyl group" means an unsaturated, linear or branched
hydrocarbon group with one or more carbon-carbon triple bonds. The
term "cyclic group" means a closed ring hydrocarbon group that is
classified as an alicyclic group, aromatic group, or heterocyclic
group. The term "alicyclic group" means a cyclic hydrocarbon group
having properties resembling those of aliphatic groups. The term
"aromatic group" or "aryl group" are defined herein below. The term
"heterocyclic group" means a closed ring hydrocarbon in which one
or more of the atoms in the ring is an element other than carbon
(e.g., nitrogen, oxygen, sulfur, etc.). The organic group can have
any suitable valency but is often monovalent or divalent.
[0010] The term "alkyl" refers to a monovalent group that is a
radical of an alkane and includes straight-chain, branched, cyclic,
and bicyclic alkyl groups, and combinations thereof, including both
unsubstituted and substituted alkyl groups. Unless otherwise
indicated, the alkyl groups typically contain from 1 to 30 carbon
atoms. In some embodiments, the alkyl groups contain 1 to 20 carbon
atoms, 1 to 10 carbon atoms, 1 to 6 carbon atoms, 1 to 4 carbon
atoms, or 1 to 3 carbon atoms. Examples of alkyl groups include,
but are not limited to, methyl, ethyl, n-propyl, n-butyl, n-pentyl,
isobutyl, t-butyl, isopropyl, n-octyl, n-heptyl, ethylhexyl,
cyclopentyl, cyclohexyl, cycloheptyl, adamantyl, norbornyl, and the
like.
[0011] The term "alkylene" refers to a divalent group that is a
radical of an alkane and includes groups that are linear, branched,
cyclic, bicyclic, or a combination thereof. Unless otherwise
indicated, the alkylene group typically has 1 to 30 carbon atoms.
In some embodiments, the alkylene group has 1 to 20 carbon atoms, 1
to 10 carbon atoms, 1 to 6 carbon atoms, or 1 to 4 carbon atoms.
Examples of alkylene groups include, but are not limited to,
methylene, ethylene, 1,3-propylene, 1,2-propylene, 1,4-butylene,
1,4-cyclohexylene, and 1,4-cyclohexyldimethylene.
[0012] The term "alkoxy" refers to a monovalent group having an oxy
group bonded directly to an alkyl group.
[0013] The term "aryl" refers to a monovalent group that is
aromatic and, optionally, carbocyclic. The aryl has at least one
aromatic ring. Any additional rings can be unsaturated, partially
saturated, saturated, or aromatic. Optionally, the aromatic ring
can have one or more additional carbocyclic rings that are fused to
the aromatic ring. Unless otherwise indicated, the aryl groups
typically contain from 6 to 30 carbon atoms. In some embodiments,
the aryl groups contain 6 to 20, 6 to 18, 6 to 16, 6 to 12, or 6 to
10 carbon atoms. Examples of an aryl group include phenyl,
naphthyl, biphenyl, phenanthryl, and anthracyl.
[0014] The term "arylene" refers to a divalent group that is
aromatic and, optionally, carbocyclic. The arylene has at least one
aromatic ring. Any additional rings can be unsaturated, partially
saturated, or saturated. Optionally, an aromatic ring can have one
or more additional carbocyclic rings that are fused to the aromatic
ring. Unless otherwise indicated, arylene groups often have 6 to 20
carbon atoms, 6 to 18 carbon atoms, 6 to 16 carbon atoms, 6 to 12
carbon atoms, or 6 to 10 carbon atoms.
[0015] The term "aralkyl" refers to a monovalent group that is an
alkyl group substituted with an aryl group (e.g., as in a benzyl
group). The term "alkaryl" refers to a monovalent group that is an
aryl substituted with an alkyl group (e.g., as in a tolyl group).
Unless otherwise indicated, for both groups, the alkyl portion
often has 1 to 10 carbon atoms, 1 to 6 carbon atoms, or 1 to 4
carbon atoms and an aryl portion often has 6 to 20 carbon atoms, 6
to 18 carbon atoms, 6 to 16 carbon atoms, 6 to 12 carbon atoms, or
6 to 10 carbon atoms.
[0016] The term "aralkylene" refers to a divalent group that is an
alkylene group substituted with an aryl group or an alkylene group
attached to an arylene group. The term "alkarylene" refers to a
divalent group that is an arylene group substituted with an alkyl
group or an arylene group attached to an alkylene group. Unless
otherwise indicated, for both groups, the alkyl or alkylene portion
typically has from 1 to 20 carbon atoms, 1 to 10 carbon atoms, 1 to
6 carbon atoms, or 1 to 4 carbon atoms. Unless otherwise indicated,
for both groups, the aryl or arylene portion typically has from 6
to 20 carbon atoms, 6 to 18 carbon atoms, 6 to 16 carbon atoms, 6
to 12 carbon atoms, or 6 to 10 carbon atoms.
[0017] The term "hydrolyzable group" refers to a group that can
react with water having a pH of 1 to 10 under conditions of
atmospheric pressure. The hydrolyzable group is often converted to
a hydroxyl group when it reacts. The hydroxyl group often undergoes
further reactions. Typical hydrolyzable groups include, but are not
limited to, alkoxy, aryloxy, aralkyloxy, alkaryloxy, acyloxy, or
halo. As used herein, the term is often used in reference to one of
more groups bonded to a silicon atom in a silyl group.
[0018] The term "alkoxy" refers to a monovalent group having an oxy
group bonded directly to an alkyl group.
[0019] The term "aryloxy" refers to a monovalent group having an
oxy group bonded directly to an aryl group.
[0020] The terms "aralkyloxy" and "alkaryloxy" refer to a
monovalent group having an oxy group bonded directly to an aralkyl
group or an alkaryl group, respectively.
[0021] The term "acyloxy" refers to a monovalent group of the
formula --O(CO)R.sup.b where R.sup.b is alkyl, aryl, aralkyl, or
alkaryl. Suitable alkyl R.sup.b groups often have 1 to 10 carbon
atoms, 1 to 6 carbon atoms, or 1 to 4 carbon atoms. Suitable aryl
R.sup.b groups often have 6 to 12 carbon atoms such as, for
example, phenyl. Suitable aralkyl and alkaryl Rb groups often have
an alkyl group with 1 to 10 carbon atoms, 1 to 6 carbon atoms, or 1
to 4 carbon atoms and an aryl having 6 to 12 carbon atoms.
[0022] The term "halo" refers to a halogen atom such as fluoro,
bromo, iodo, or chloro. When part of a reactive silyl, the halo
group is often chloro.
[0023] The term "(meth)acryloyloxy group" includes an acryloyloxy
group (--O--(CO)--CH.dbd.CH.sub.2) and a methacryloyloxy group
(--O--(CO)--C(CH.sub.3).dbd.CH.sub.2).
[0024] The term "(meth)acryloylamino group" includes an
acryloylamino group (--NR--(CO)--CH.dbd.CH.sub.2) and a
methacryloylamino group (--NR--(CO)--C(CH.sub.3).dbd.CH.sub.2)
including embodiments wherein the amide nitrogen is bonded to a
hydrogen, methyl group, or ethyl group (R is H, methyl, or
ethyl).
[0025] The terms "comprises" and variations thereof do not have a
limiting meaning where these terms appear in the description and
claims.
[0026] The words "preferred" and "preferably" refer to embodiments
of the disclosure that may afford certain benefits, under certain
circumstances. However, other embodiments may also be preferred,
under the same or other circumstances. Furthermore, the recitation
of one or more preferred embodiments does not imply that other
embodiments are not useful, and is not intended to exclude other
embodiments from the scope of the disclosure.
[0027] In this application, terms such as "a," "an," and "the" are
not intended to refer to only a singular entity, but include the
general class of which a specific example may be used for
illustration. The terms "a," "an," and "the" are used
interchangeably with the term "at least one." The phrases "at least
one of" and "comprises at least one of" followed by a list refers
to any one of the items in the list and any combination of two or
more items in the list.
[0028] As used herein, the term "or" is generally employed in its
usual sense including "and/or" unless the content clearly dictates
otherwise. The term "and/or" means one or all of the listed
elements or a combination of any two or more of the listed
elements.
[0029] Also herein, all numbers are assumed to be modified by the
term "about" and preferably by the term "exactly." As used herein,
in connection with a measured quantity, the term "about" refers to
that variation in the measured quantity as would be expected by the
skilled artisan making the measurement and exercising a level of
care commensurate with the objective of the measurement and the
precision of the measuring equipment used.
[0030] Also herein, the recitations of numerical ranges by
endpoints include all numbers subsumed within that range as well as
the endpoints (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4,
5, etc.).
[0031] When a group is present more than once in a formula
described herein, each group is "independently" selected, whether
specifically stated or not. For example, when more than one R group
is present in a formula, each R group is independently selected.
Furthermore, subgroups contained within these groups are also
independently selected. For example, when each R group contains a Y
group, each Y is also independently selected.
[0032] As used herein, the term "room temperature" refers to a
temperature of 20.degree. C. to 25.degree. C. or 22.degree. C. to
25.degree. C.
[0033] The above summary of the present disclosure is not intended
to describe each disclosed embodiment or every implementation of
the present disclosure. The description that follows more
particularly exemplifies illustrative embodiments. In several
places throughout the application, guidance is provided through
lists of examples, which examples can be used in various
combinations. In each instance, the recited list serves only as a
representative group and should not be interpreted as an exclusive
list.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0034] The present disclosure provides curable silsesquioxane (SSQ)
polymers that have excellent outdoor weatherability, as well as
desirable UV and moisture resistance properties that make them good
for preparing protective coatings.
[0035] In one embodiment, the present disclosure provides a curable
composition that includes a photoinitiator (e.g., a free-radical
initiator) and a curable silsesquioxane polymer of the present
disclosure. In certain embodiments, the curable composition can
optionally include nanoparticles (e.g., silica, titania, or
zirconia) that can impart hardness to the coating. In certain
embodiments, the curable composition can optionally include an
organic solvent.
[0036] This technology can provide a weatherable silsesquioxane
glass coating or hard coating that has multiple applications. For
example, such coatings can be used as anti-scratch and
anti-abrasion coatings for various polycarbonate lens and
polyesters films, which require additional properties such as
optical clarity, durability, hydrophobicity, etc., or any other
application where use of temperature, radiation, or moisture may
cause degradation of films.
[0037] In one embodiment, the present disclosure provides a curable
silsesquioxane polymer that includes a three-dimensional branched
network having the formula:
##STR00003##
wherein the oxygen atom at the * is bonded to another Si atom
within the three-dimensional branched network.
[0038] In certain embodiments of the curable silsesquioxane
polymer, R is an organic group that includes an ethylenically
unsaturated group. In certain embodiments of the curable
silsesquioxane polymer, R has the formula --Y--Z.
[0039] In certain embodiments of the curable silsesquioxane
polymer, n is an integer of greater than 3. In certain embodiments,
n is an integer of at least 10. In certain embodiments, n is an
integer of no greater than 100. In certain embodiments, n is an
integer of no greater than 25.
[0040] In certain embodiments of the curable silsesquioxane
polymer, the --OH groups are present in an amount of at least 15
wt-% of the polymer. In certain embodiments, the --OH groups are
present in an amount of at least 20 wt-% of the polymer. In certain
embodiments, the --OH groups are present in an amount of no greater
than 60 wt-% of the polymer. In certain embodiments, the --OH
groups are present in an amount of no greater than 50 wt-% of the
polymer. In certain embodiments, the --OH groups are present in an
amount of no greater than 30 wt-% of the polymer.
[0041] In one embodiment, the present disclosure provides a curable
silsesquioxane polymer that includes a three-dimensional branched
network which is a condensation reaction product of a compound
having the formula Z--Y--Si(R.sup.1).sub.3.
[0042] In certain embodiments of the R group of the curable
silsesquioxane polymer and/or the reactant
Z--Y--Si(R.sup.1).sub.3,Y is a bond, an alkylene group, an arylene
group, or a combination thereof. In certain embodiments, Y is a
bond, a (C1-C20)alkylene group, a (C6-C12)arylene group, a
(C6-C12)alk(C1-C20)arylene group, a (C6-C12)ar(C1-C20)alkylene
group, or a combination thereof.
[0043] In certain embodiments of the R group of the curable
silsesquioxane polymer and/or the reactant Z--Y--Si(R.sup.1).sub.3,
Z is an ethylenically unsaturated group selected from a vinyl
group, a vinylether group, a (meth)acryloyloxy group, and a
(meth)acryloylamino group (including embodiments wherein the
nitrogen is optionally substituted with an alkyl such as methyl or
ethyl). In certain embodiments, Z is a vinyl group.
[0044] In certain embodiments of the R group of the curable
silsesquioxane polymer and/or the reactant Z--Y--Si(R.sup.1).sub.3,
each R.sup.1 group is independently a hydrolyzable group. In
certain embodiments of R.sup.1, the hydrolyzable group is selected
from an alkoxy, aryloxy, aralkyloxy, alkaryloxy, acyloxy, and halo.
In certain embodiments of R.sup.1, the hydrolyzable group is an
alkoxy group.
[0045] Curable silsesquioxane polymers can be made by the
condensation of reactants of the formula Z--Y--Si(R.sup.1).sub.3.
Examples of such reactants include vinyltriethoxysilane,
allyltriethoxysilane, allylphenylpropyltriethoxysilane,
3-butenyltriethoxysilane, docosenyltriethoxysilane, and
hexenyltriethoxysilane. Condensation of such reactants can be
carried out using conventional techniques, as exemplified in the
Examples Section.
[0046] Exemplary silsesquioxane polymers of the present disclosure
can be made by the condensation of exemplary reactants of the
formula Z--Y--Si(R.sup.1).sub.3 as follows:
##STR00004##
[0047] These polymers are poly(vinylsilsesquioxane) (A),
poly(allylsilsesquioxane) (B),
poly(allylphenylpropylsilsesquioxane) (C),
poly(3-butenylsilsesquioxane) (D), poly(docosenyl silsesquioxane)
(E), and poly(hexenylsilsesquioxane) (F).
[0048] An exemplary curable silsesquioxane polymer of the present
disclosure that has the general formula:
##STR00005##
has the following more specific three-dimensional branched network
structure (wherein the oxygen atom in the formula above at the *
above is bonded to another Si atom within the three-dimensional
branched network; R is a vinyl group; n is an integer of greater
than 3; and the --OH groups are present in an amount of at least 15
wt-% of the polymer):
##STR00006##
[0049] The curable silsesquioxane polymers are generally tacky,
soluble in organic solvents (particularly polar organic solvents),
and coatable. Thus, such curable silsesquioxane polymers can be
easily processed. They can be easily applied to a substrate. They
also adhere well to a variety of substrates. For example, in
certain embodiments, a curable silsesquioxane polymer of the
present disclosure has peel force from glass of at least 1 Newtons
per decimeter (N/dm), or at least 2 N/dm, per the Method for Peel
Adhesion Measurement detailed in the Examples Section. In certain
embodiments, a curable silsesquioxane polymer of the present
disclosure has peel force from glass of no greater than 6 N/dm, per
the Method for Peel Adhesion Measurement detailed in the Examples
Section.
[0050] Such curable silsesquioxane polymers can be combined with a
photoinitiator and UV cured. Suitable photoinitiators include a
variety of free-radical photoinitiators. Exemplary free-radical
photoinitiators can be selected from benzophenone,
4-methylbenzophenone, benzoyl benzoate, phenylacetophenones,
2,2-dimethoxy-2-phenylacetophenone,
alpha,alpha-diethoxyacetophenone,
1-hydroxy-cyclohexyl-phenyl-ketone (available under the trade
designation IRGACURE 184 from BASF Corp., Florham Park, N.J.),
2-hydroxy-2-methyl-1-phenylpropan-1-one,
bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentyl phosphine oxide,
2-hydroxy-2-methyl-1-phenylpropan-1-one,
2-hydroxy-2-methyl-1-phenylpropan-1-one (available under the trade
designation DAROCURE 1173 from BASF Corp.),
2,4,6-trimethylbenzoyl-diphenylphosphine oxide, and combinations
thereof (e.g., a 50:50 by wt. mixture of
2,4,6-trimethylbenzoyl-diphenylphosphine oxide and
2-hydroxy-2-methyl-1-phenylpropan-1-one, available under the trade
designation DAROCURE 4265 from BASF Corp.).
[0051] A photoinitiator is typically present in a coating
composition in an amount of at least 0.01 percent by weight (wt-%),
based on the total weight of curable material in the coating
composition. A photoinitiator is typically present in a coating
composition in an amount of no greater than 5 wt-%, based on the
total weight of curable material in the coating composition.
[0052] Such curable silsesquioxane polymers can be combined with
nanoparticles that can impart hardness to a coating. Suitable
nanoparticles of the present disclosure include an inorganic oxide.
Exemplary nanoparticle can include an oxide of a non-metal, an
oxide of a metal, or combinations thereof. An oxide of a non-metal
includes an oxide of, for example, silicon or germanium. An oxide
of a metal includes an oxide of, for example, iron, titanium,
cerium, aluminum, zirconium, vanadium, zinc, antimony, and tin. A
combination of a metal and non-metal oxide includes an oxide of
aluminum and silicon.
[0053] The nanoparticle can have an average particle size of no
greater than 100 nanometers (nm), no greater than 75 nanometers, no
greater than 50 nanometers, no greater than 25 nanometers, no
greater than 20 nanometers, no greater than 15 nanometers, or no
greater than 10 nanometers. The nanoparticle can have an average
particle size of at least 1 nanometer, at least 5 nanometers, at
least 15 nanometers, at least 20 nanometers, at least 25
nanometers, at least 50 nanometers, or at least 75 nanometers.
[0054] Various nanoparticles are commercially available. Commercial
sources of nanoparticles are available from Nyacol Co., Ashland,
Mass., Solvay-Rhodia (Lyon, France), and Nalco Co., Naperville,
Ill. Nanoparticles can also be made using techniques known in the
art. For example, zirconia nanoparticles can be prepared using
hydrothermal technology, as described for example in PCT
Publication No. WO2009/085926 (Kolb et al.). Suitable zirconia
nanoparticles are also those described in, for example, U.S. Pat.
No. 7,241,437 (Davidson, et al.).
[0055] In some embodiments, the nanoparticles may be in the form of
a colloidal dispersion. Colloidal silica nanoparticles in a polar
solvent are particularly desirable. Silica sols in a polar solvent
such as isopropanol are available commercially under the trade
names ORGANOSILICASOL IPA-ST-ZL, ORGANOSILICASOL IPA-ST-L, and
ORGANOSILICASOL IPA-ST from Nissan Chemical Industries, Ltd.,
Chiyoda-Ku Tokyo, Japan.
[0056] Preferably, the nanoparticles are dispersed in a curable
coating composition of the present disclosure. If used,
nanoparticles are typically present in a curable coating
composition in an amount of at least 5 wt-%, based on the total
weight of the composition. If used, nanoparticles are typically
present in a curable coating composition in an amount of no greater
than 80 wt-%, or no greater than 50 wt-%, based on the total weight
of the composition. Depending on the particle size of the
nanoparticles and the amount of nanoparticles added, certain
compositions may be hazy. For example, a composition that includes
over 50 wt-% of 10 nanometer nanoparticles may be hazy, but such
composition can be useful for certain applications.
[0057] A coating composition that includes a curable silsesquioxane
polymer, a photoinitiator, and optional nanoparticles, can also
include an optional organic solvent, if desired. Useful solvents
for the coating compositions include those in which the compound is
soluble at the level desired. Typically, such organic solvent is a
polar organic solvent. Exemplary useful polar solvents include, but
are not limited to, ethanol, isopropanol, methyl ethyl ketone,
methyl isobutyl ketone, dimethylformamide, and tetrahydrofuran.
These solvents can be used alone or as mixtures thereof.
[0058] Any amount of the optional organic solvent can be used. For
example, the curable coating compositions can include up to 50 wt-%
or even more of organic solvent. The solvent can be added to
provide the desired viscosity to the coating composition. In some
embodiments, no solvent or only low levels (e.g., up to 10 wt-%) of
organic solvent is used in the curable coating composition.
[0059] The coating composition is typically a homogeneous mixture
(e.g., of just the curable silsesquioxane polymer and
photoinitiator) that has a viscosity appropriate to the application
conditions and method. For example, a material to be brush or
roller coated would likely be preferred to have a higher viscosity
than a dip coating composition. Typically, a coating composition
includes at least 5 wt-%, of the polymer, based on the total weight
of the coating composition. A coating composition often includes no
greater than 80 wt-%, of the polymer, based on the total weight of
the coating composition.
[0060] A wide variety of coating methods can be used to apply a
composition of the present disclosure, such as brushing, spraying,
dipping, rolling, spreading, and the like. Other coating methods
can also be used, particularly if no solvent is included in the
coating composition. Such methods include knife coating, gravure
coating, die coating, and extrusion coating, for example.
[0061] A curable coating composition of the present disclosure can
be applied in a continuous or patterned layer. Such layer can be
disposed on at least a portion of at least one surface of the
substrate. If the curable composition includes an organic solvent,
the coated curable composition can be exposed to conditions that
allow the organic solvent to evaporate from the curable composition
before UV curing the curable composition. Such conditions include,
for example, exposing the composition to room temperature, or an
elevated temperature (e.g., 60.degree. C. to 70.degree. C.).
[0062] Curing of a curable composition of the present disclosure
occurs using UV radiation. Typically, the curing occurs for a time
effective to render the coating sufficiently non-tacky to the
touch.
An exemplary UV-cured silsesquioxane polymer of the present
disclosure has the following three-dimensional branched network
structure (with residual R (e.g., vinyl) groups):
##STR00007##
[0063] The substrate on which the coating can be disposed can be
any of a wide variety of hard or flexible materials. Useful
substrates include ceramics, siliceous substrates including glass,
metal, natural and man-made stone, and polymeric materials,
including thermoplastics and thermosets. Suitable materials
include, for example, poly(meth)acrylates, polycarbonates,
polystyrenes, styrene copolymers such as styrene acrylonitrile
copolymers, polyesters, polyethylene terephthalate.
[0064] The following is a list of illustrative embodiments of the
present disclosure.
ILLUSTRATIVE EMBODIMENTS
[0065] 1. A curable silsesquioxane polymer comprising a
three-dimensional branched network having the formula:
##STR00008##
wherein:
[0066] the oxygen atom at the * is bonded to another Si atom within
the three-dimensional branched network;
[0067] R is an organic group comprising an ethylenically
unsaturated group;
[0068] n is an integer of greater than 3; and
[0069] the --OH groups are present in an amount of at least 15 wt-%
of the polymer.
2. The curable silsesquioxane polymer of embodiment 1 wherein the
--OH groups are present in an amount of at least 20 wt-% of the
polymer. 3. The curable silsesquioxane polymer of embodiment 1 or 2
wherein the --OH groups are present in an amount of no greater than
60 wt-% of the polymer. 4. The curable silsesquioxane polymer of
embodiment 3 wherein the --OH groups are present in an amount of no
greater than 50 wt-% of the polymer. 5. The curable silsesquioxane
polymer of embodiment 4 wherein the --OH groups are present in an
amount of no greater than 30 wt-% of the polymer. 6. The curable
silsesquioxane polymer of any one of embodiments 1 through 5
wherein n is an integer of at least 10. 7. The curable
silsesquioxane polymer of any one of embodiments 1 through 6
wherein n is an integer of no greater than 100. 8. The curable
silsesquioxane polymer of embodiment 7 wherein n is an integer of
no greater than 25. 9. The curable silsesquioxane polymer of any
one of embodiments 1 through 8 wherein R has the formula --Y--Z,
wherein Y is a bond, an alkylene group, an arylene group, or a
combination thereof, and Z is an ethylenically unsaturated group
selected from a vinyl group, a vinylether group, a
(meth)acryloyloxy group, and a (meth)acryloylamino group (including
embodiments wherein the nitrogen is optionally substituted with
methyl or ethyl). 10. The curable silsesquioxane polymer of
embodiment 9 wherein Y is a bond, a (C1-C20)alkylene group, a
(C6-C12)arylene group, a (C6-C12)alk(C1-C20)arylene group, a
(C6-C12)ar(C1-C20)alkylene group, or a combination thereof. 11. The
curable silsesquioxane polymer of embodiment 9 or 10 wherein Z is a
vinyl group. 12. The curable silsesquioxane polymer of any one of
embodiments 1 through 11 which has peel force from glass of at
least 1 N/dm. 13. The curable silsesquioxane polymer of embodiment
12 which has peel force from glass of at least 2 N/dm. 14. The
curable silsesquioxane polymer of any one of embodiments 1 through
13 which has peel force from glass of no greater than 6 N/dm. 15. A
curable silsesquioxane polymer comprising a three-dimensional
branched network which is a condensation reaction product of a
compound having the formula Z--Y--Si(R.sup.1).sub.3, wherein:
[0070] Y is a bond, an alkylene group, an arylene group, or a
combination thereof;
[0071] Z is an ethylenically unsaturated group selected from a
vinyl group, a vinylether group, a (meth)acryloyloxy group, and a
(meth)acryloylamino group (including embodiments wherein the
nitrogen is optionally substituted with methyl or ethyl); and
[0072] each R.sup.1 group is independently a hydrolyzable
group;
[0073] wherein the polymer includes --OH groups in an amount of at
least 15 wt-% of the polymer.
16. The curable silsesquioxane polymer of embodiment 15 wherein Y
is a bond, a (C1-C20)alkylene group, a (C6-C12)arylene group, a
(C6-C12)alk(C1-C20)arylene group, a (C6-C12)ar(C1-C20)alkylene
group, or a combination thereof. 17. The curable silsesquioxane
polymer of embodiment 15 or 16 wherein Z is a vinyl group. 18. The
curable silsesquioxane polymer of any one of embodiments 15 through
17 wherein the hydrolyzable group is selected from an alkoxy,
aryloxy, aralkyloxy, alkaryloxy, acyloxy, and halo. 19. The curable
silsesquioxane polymer of embodiment 18 wherein the hydrolyzable
group is an alkoxy group. 20. The curable silsesquioxane polymer of
any one of embodiments 15 through 19 wherein the --OH groups are
present in an amount of at least 20 wt-% of the polymer. 21. The
curable silsesquioxane polymer of any one of embodiments 15 through
20 wherein the --OH groups are present in an amount of no greater
than 60 wt-% of the polymer. 22. The curable silsesquioxane polymer
of embodiment 21 wherein the --OH groups are present in an amount
of no greater than 50 wt-% of the polymer. 23. The curable
silsesquioxane polymer of embodiment 22 wherein the --OH groups are
present in an amount of no greater than 30 wt-% of the polymer. 24.
The curable silsesquioxane polymer of any one of embodiments 15
through 23 which has peel force from glass of at least 1 N/dm. 25.
The curable silsesquioxane polymer of embodiment 24 which has peel
force from glass of at least 2 N/dm. 26. The curable silsesquioxane
polymer of any one of embodiments 15 through 25 which has peel
force from glass of no greater than 6 N/dm. 27. A curable
composition comprising a photoinitiator and the curable
silsesquioxane polymer of any one of embodiments 1 through 26. 28.
The curable composition of embodiment 27 wherein the photoinitiator
is a free-radical photoinitiator. 29. The curable composition of
embodiment 28 wherein the free-radical photoinitiator is selected
from benzophenone, 4-methylbenzophenone, benzoyl benzoate,
phenylacetophenones, 2,2-dimethoxy-2-phenylacetophenone,
alpha,alpha-diethoxyacetophenone, hydroxycyclo-hexylphenylketone,
2-hydroxy-2-methyl-1-phenylpropan-1-one,
bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentyl phosphine oxide,
2-hydroxy-2-methyl-1-phenylpropan-1-one,
2-hydroxy-2-methyl-1-phenylpropan-1-one,
2,4,6-trimethylbenzoyl-diphenylphosphine oxide, and combinations
thereof 30. The curable composition of any one of embodiments 27
through 29 further comprising nanoparticles. 31. The curable
composition of embodiment 30 wherein the nanoparticles comprise
silica nanoparticles. 32. The curable composition of any one of
embodiments 27 through 31 further comprising an organic solvent.
33. The curable composition of embodiment 32 wherein the organic
solvent is a polar solvent. 34. The curable composition of
embodiment 33 wherein the polar organic solvent comprises
isopropanol, methyl ethyl ketone, methyl isobutyl alcohol, ethanol,
tetrahydrofuran, dimethylformamide, or combinations thereof 35. An
article comprising a substrate and the curable composition of any
one of embodiments 27 through 34 in a layer disposed on at least a
portion of at least one surface of the substrate. 36. The article
of embodiment 35 wherein the layer is patterned. 37. An article
comprising a substrate and a cured coating layer prepared by UV
curing the composition of any one of embodiments 27 through 34
disposed on at least a portion of at least one surface of the
substrate. 38. The article of embodiment 37 wherein the layer is
patterned. 39. A method of making a cured coating on a substrate
surface, the method comprising:
[0074] coating a curable composition of any one of embodiments 27
through 34 on at least a portion of at least one substrate
surface;
[0075] optionally exposing the coated curable composition to
conditions that allow an organic solvent, if present, to evaporate
from the curable composition; and
[0076] UV curing the curable composition.
40. The method of embodiment 39 wherein the curable silsesquioxane
polymer is prepared by a method comprising subjecting a compound of
the formula Z--Y--Si(R.sup.1).sub.3 to a condensation reaction;
[0077] wherein: [0078] Y is a bond, an alkylene group, an arylene
group, or a combination thereof; [0079] Z is an ethylenically
unsaturated group selected from a vinyl group, a vinylether group,
a (meth)acryloyloxy group, and a (meth)acryloylamino group
(including embodiments wherein the nitrogen is optionally
substituted with methyl or ethyl); and [0080] each R.sup.1 group is
independently a hydrolyzable group;
[0081] wherein the polymer includes --OH groups in an amount of at
least 15 wt-% of the polymer.
EXAMPLES
[0082] Objects and advantages of this invention are further
illustrated by the following examples, but the particular materials
and amounts thereof recited in these examples, as well as other
conditions and details, should not be construed to unduly limit
this invention. These examples are merely for illustrative purposes
only and are not meant to be limiting on the scope of the appended
claims.
Materials
[0083] Unless otherwise noted, all parts, percentages, ratios,
etc., in the examples and in the remainder of the specification are
by weight. Unless otherwise noted, all chemicals were obtained or
are available from, chemical suppliers such as Aldrich Chemical
Company, Milwaukee, Wis.
TABLE-US-00001 Designation Description Supplier MONOMER-1
Vinyltriethoxysilane Gelest, Inc., MONOMER-2 Allyltriethoxysilane
Morrisville, PA MONOMER-3 Allylphenylpropyltriethoxysilane
MONOMER-4 3-Butenyltriethoxysilane MONOMER-5
Docosenyltriethoxysilane MONOMER-6 Hexenyltriethoxysilane "IRGACURE
184" 1-Hydroxy-cyclohexyl-phenyl- BASF Corporation, ketone Florham
Park, NJ "DAROCURE 1173" 2-Hydroxy-2-methyl-1- phenylpropan-1-one
"DAROCURE 4265" 50:50 by wt. mixture of 2,4,6- Trimethylbenzoyl-
diphenylphosphine oxide and 2- hydroxy-2-methyl-1-
phenylpropan-1-one "IPA-ST-ZL" Colloidal silica sol, 70-100 nm
Nissan Chemical particle size, 30 wt-% in IPA Industries, Ltd.,
commercially available under Chiyoda-Ku Tokyo, trade designation
Japan "ORGANOSILICASOL IPA-ST-ZL" "IPA-ST-L" Colloidal silica sol,
40-50 nm particle size, 30 wt-% in IPA commercially available under
trade designation "ORGANOSILICASOL IPA-ST-L" "IPA-ST" Colloidal
silica sol, 10-15 nm particle size, 30 wt-% in IPA commercially
available under trade designation "ORGANOSILICASOL IPA-ST" MEK
Methyl ethyl ketone Sigma-Aldrich IPA Isopropanol Chemical Company,
St. Louis, MO 3SAB PET 2-mil (0.058 millimeter (mm)) Mitsubishi
Polyester thick polyester terephthalate Film, Greer, SC (PET) film,
which has one side chemically treated or primed to improve the
adhesion of silicone coatings, commercially available under the
trade designation "HOSTAPHAN 3SAB"
Test Methods
Method for Peel Adhesion Measurement
[0084] Poly(vinylsilsesquioxane) (50 wt-% solution in methyl ethyl
ketone) samples prepared according to EX1 and CE1, described below,
were coated on 3SAB PET films using a knife coater to provide a dry
coating having a thickness of 2-3 mil (0.058-0.076 mm). The coated
PET films were placed in a forced air drying oven maintained at
70.degree. C. (for 2 minutes) to evaporate the solvent. After
drying, the coated PET films were cut into samples for measuring
peel adhesion according to the method described below.
[0085] Peel adhesion of EX1 and CE1 samples was then measured with
an IMASS SP-2000 peel tester (obtained from IMASS, Inc., Accord,
Mass.) using 0.5 inch by 5 inch (about 1.25 cm by 12.7 cm) samples.
The samples were applied to a clean glass panel using four total
passes of a 2 kg-rubber roller. Prior to testing, the samples were
allowed to dwell for 20 minutes at room temperature and 50 percent
relative humidity. The panel was then mounted on the IMASS SP-2000
peel tester, and the samples were pulled off of the panel at a 90
degree angle at a speed of 30.48 cm/minute. Peel force was measured
in units of ounces per inch (oz/inch) and was used to calculate the
average peel force for a minimum of three samples and was then
converted to Newtons per decimeter (N/dm).
Procedure for the Calculation of (%) OH Groups by FTIR
[0086] The amount of --OH groups present in the samples prepared
according to the EX1 and CE1, described below, was determined as
follows. About 0.1 g of poly(vinylsilsesquioxane) was applied as
uniform thin layer directly on to a dried potassium bromide pellet
and thereafter directly was analyzed by Fourier Transform Infrared
Spectroscopy (FTIR), (Model Nicolet 6700 FTIR, from Thermo Fisher
Scientific, Madison, Wis.). Using integration software ("OMNIC"
software version 7.3, obtained from Thermo Fisher Scientific,
Madison, Wis.), the total peak area from 500 cm.sup.-1 to 4000
cm.sup.-1 was calculated along with the area of the broad --OH
absorbance peak from 3100 to 3600 cm.sup.-1. The % OH was
calculated by taking area of the --OH absorbance peak versus the
total peak area.
Method for Pencil Hardness
[0087] ASTM D3363-05 (2011)e2 "Standard Test Method for Film
Hardness by Pencil Test" (available from ASTM International, West
Conshohocken, Pa.) was used to ascertain the hardness of the cured
films prepared according to the examples and comparative examples
described below. Apparatus used in this study was ELCOMETER 3086
Scratch Boy (obtained from Elcometer Instruments Limited, Mich.).
Pencil hardness was measured by moving a pencil of a designated
hardness grade (i.e., 9B, 8B, 7B, 6B, 5B, 4B, 3B, 2B, B, HB, F, H,
2H, 3H, 4H, 5H, 6H, 7H, 8H, 9H, from the softest grade to hardest
grade pencil), and thereafter looking at the surface under a
microscope to find if the surface was scratched. The sample was
designated a hardness value corresponding to the hardest pencil
that did not microscopically scratch the surface of the sample.
Examples 1-6 (EX1-EX6) and Comparative Example 1 (CE1)
[0088] For CE1, MONOMER 1 (100 g), DI water (50 g), and oxalic acid
(0.5 g) were mixed together at room temperature in a 500 mL round
bottom flask equipped with a condenser. The mixture was stirred at
70.degree. C. for 24 hours followed by the partial evaporation of
the solvents (water/ethanol mixture). The resulting solid was
washed three-times with DI water (100 mL). After washing, the MEK
was evaporated under reduced pressure to yield highly cross-linked
polyvinylsilsesquioxane.
[0089] For EX1, MONOMER 1 (100 g), distilled (DI) water (50 g), and
oxalic acid (0.5 g) were mixed together at room temperature in a
500 mL round bottom flask equipped with a condenser. The mixture
was stirred at room temperature for 6-8 hours followed by the
evaporation of the solvents (water/ethanol mixture). The resulting
liquid was dissolved in MEK (100 mL) and washed three-times with DI
water (100 mL). After washing, the MEK was evaporated under reduced
pressure to yield polymer product polyvinylsilsesquioxane as a
viscous liquid.
[0090] EX2-EX6 polymers were prepared in the same manner as EX1,
using their respective monomers listed in Table 1, below.
TABLE-US-00002 TABLE 1 Example Monomer Polymer EX2 MONOMER-2
Poly(allylsilsesquioxane) EX3 MONOMER-3
Poly(allylphenylpropylsilsesquioxane) EX4 MONOMER-4
Poly(3-butenylsilsesquioxane) EX5 MONOMER-5
Poly(docosenylsilsesquioxane) EX6 MONOMER-6
Hexenylsilsesquioxane
[0091] EX1 and CE1 samples were tested to determine the % (--OH)
groups present as well as the average peel adhesion using the
methods described above. The data is presented in Table 2,
below.
TABLE-US-00003 TABLE 2 Example Average Peel Adhesion (N/dm) %
(--OH) EX1 4.36 25.6 CE1 0.10 11.7
Example 7--(EX7)
[0092] Poly(vinylsilsesquioxane) (30 g), prepared above in EX1, was
dissolved in 100 g of IPA:MEK (70:30 by wt.) mixture followed by
the addition of IRGACURE 184 (0.3 g). Using #8 Mayer Rod, the
mixture was then coated on a 3SAB PET film. The coated film was
passed through a "LIGHT HAMMER 6" UV-chamber (obtained from Fusion
UV Systems, Inc. Gaithersburg, Md., under trade designation "LIGHT
HAMMER 6") equipped with an H-bulb located at 5.3 cm above sample
at 12 meters/minute to cure the coating. The coating was cured to
touch and adhered well to PET film. The pencil hardness of the
cured EX7 sample determined using the method described above was
3H.
Examples 8-11 (EX8-EX11)
[0093] EX8-EX11 were prepared in the same manner as EX7, except
that the polysilsesquioxane and the photoinitiator were varied as
summarized in Table 3, below. The EX8-EX11 samples were cured to
touch and adhered well to PET film. The pencil hardness of the
cured EX8 and EX9 samples was 2H.
TABLE-US-00004 TABLE 3 Example Polysilsesquioxane Photoinitiator
Pencil Hardness EX8 EX2 IRGACURE 184 3H EX9 EX3 IRGACURE 184 3H
EX10 EX1 DAROCURE 1173 3H EX11 EX1 DAROCURE 4265 3H
Examples 12-14 (EX12-EX14)
[0094] EX12-EX14 were prepared in the same manner as EX7, except
that the corresponding coating mixtures further contained 40 g of
IPA-ST-L, 60 g of IPA-ST, and 10 g of IPA-ST-ZL silica sol,
respectively. The EX12-EX14 samples were cured to touch and adhered
well to PET film.
[0095] The complete disclosures of the patents, patent documents,
and publications cited herein are incorporated by reference in
their entirety as if each were individually incorporated. Various
modifications and alterations to this disclosure will become
apparent to those skilled in the art without departing from the
scope and spirit of this disclosure. It should be understood that
this disclosure is not intended to be unduly limited by the
illustrative embodiments and examples set forth herein and that
such examples and embodiments are presented by way of example only
with the scope of the disclosure intended to be limited only by the
claims set forth herein as follows.
* * * * *