Note: Descriptions are shown in the official language in which they were submitted.
It is advantageous to protect soft surfaces against abrasion by
applying a protective coating to the soft surface. This application relates
to new and improved abras:ion resistant coatings made from ambif~mctional
silanes.
Much prior art is available in the area of abrasion resistant
coatings, but the most relevant art found has been ~nited States Patents
3,687,882; 3,637,416; 3,642,681; 3,708,225; 3,460,956; 3,762,981; and
2,768,909; and Japanese Patent No. 49-117529, issued November 9, 1974~ The
present invention overcomes some deficiencies of the prior art and displays
10 a high degree of abrasion resistance, little lprocessing (especially no ~ :
requirement for hydrolysis of substituents), moderate curing temperatures,
good corrosion and solvent resistance and exhibit low surface energy to
which foreign particles do not readily adhereO
The coatings are applicable to any soft or damageable surface
including plastics, natural materials, metals, ceramics and glass.
The process aspect of the present invention is the protection of a
substrate by applying to said substrate a thin coating of a composition : ~;
comprising: ~
(1) an epoxy~silane, methacryloxy-silane and/or vinyl silane, and ~:
(2) a metal ester selected from the group comprising aluminum,
titanium or zirconium having at least two ester groups of
the formula -OR directly bounded to the metal wherein R is ;~
hydrocarbyl of 1 to 18 carbon atoms, and more preferably alkyl
` or acyl of 1 to 8 carbon atoms. The;remaining valences of
. the metal may be satisfied by organic moieties, inorganic
moieties, complexing agents or even repeating -O-Tl-O- groups,
.~ etc~ ~Preferably, if OR groups are not used, halides or
alkyl groups are used). As long as two of the ester groups
are present, the metal ester.can react into the final poly-
meric structure to form an abrasion resistant coating, and
curing said composition
:...
The present invention also provides a solvent resistant, abrasion
resistant film col~rising the reclc-tion product of
(a) applying to said substrate a composition consisting of:
Il) a metal ester selected from ~he group comprising titanium
aluminum or zirconium; having at least two ester groups of the formula -OR
bonded to the metal and wherein R is hydrocarbyl of 1 to 18 carbon atoms; and
~ 2) a reactive silane selected from epoxy-silanes, methac~yloxy~
silanes and/or vinyl-silanes; and
~b) a reactive silane selected from epoxy-silanes, methacryloxy-
silanes and/or vinyl-sil~nes.
It is generally preferred ~hat all valences of the metal are
satisfied by ester groupsJ but the other groups may be present so long as
at lea~st two ester groups are present. Compounds of the formula
RtM~OR)m n
are therefore useful, wherein R is as defined above, m is the valence of M
and n is 0, 1, or 2 such that m-n is always a~ leas~ 2; and R' is an organic
or inorganic moiety bonded to M or a complexing agent satisfying the valence
requirements of M. Compounds of the ~ormula
M(OR~m
are generally preferred because of availability and generally improved
characteristics. Examples of these preferred compounds are tetraisopropyl
titanate, tetrabutyl titanate, tetra-2-ethylhexyl titanate, tetraethyl
titanate, aluminum isopropoxide, aluminum n-butoxide~ and tetraisopropyl
titanate,
It is critical that the metal ester not be hydrolyzed completely
or hydrolyzed to a condition where less than two ester groups per titanium
atom are present on the metal ester. If the metal ester is so hydrolyzed~
the ambifunctionalsil~ne and the metal ester will coprecipitate into
A 2~
. ~
an inso:Lublt? mate~laL becallse reactive sites f`or the sllane on
the ester havebeerl renlovecl.
The preserlt coat;ing compositions are prepared simply
b,y the admixing or blendlrlg of the metal ester and ambi-
functional silane at room temperature (e.g., 25C.) andallowing the materials to react. Other additives such as
leveling agents, colorants and viscos:lty modifiers may be
included by mixing ~hem with the ester and silane. Typically,
; the coating composition is filtered through a 10 micron filter
before application.
It is pref'erred that the reactants in the coating
compositions not be hydrolyzed. Although reactants which are
partially hydrolyzed can be used, the amount of water which
may be present in the compositions must not be more than
one-half equivalent per equivalent of metal ester. For
example, use of water over this amount in compositions con-
taining titanium ester results in formation of titanium
dioxide which readily precipitates out of the composition.
Another disadvantage with the use of hydrolyzed reactant is
that an additional step is required in the preparation of the
coating compositions. Furthermore, hydrolyzed reactants do
not possess the desirable shelf stability exhibited by
unhydrolyzed reactants.
Reactive silanes useful in the practice of the
present invention include those represented by the following
~formula:
'' CRl ] Si - [R2
wherein R is selected from a vinyl group,
~ 3 ~
:,~. '- ' , . .
C112 = C~l -
a methacryloxy gro~lp,
CH2 = C - C - 0 - R3 -
or an epoxy group,
O~ r
CH2 - CH - R m ~ or L ~ ( m) ~
wherein R3 is an alkylene group of 1 to 8 carbon atoms~ ancl R4 i5 hydrogen
or hydrocarbyl radical of 1 to 8 carbon atoms (preferably alkyl) and R5 =
divalent hydrocarbon radical (aliphatic, aromatic, or aliphatic and aromatic
containing) of less than 20 carbon atoms or a divalent radical of less than
20 carbon atoms composed of C, H, N, S, and 0 atoms (these atoms are the
only atoms which may appear in the backbone of the divalent radicals), the
last being in the form of ether linkages. No two hetero atoms may be adjacent
within the backbone of the divalent hydrocarbon radical. The value of m is
1, 2 or 3 and n is 0 or 1. R2 is an oxyhydrocarbyl group, preferably alkoxy,
acyl, or acetoxy, having 1 to 8 carbon atoms or a radical of formula
(CH2CH20)kZ in which k is an integer of at least 1 and Z is an aliphatic
hydrocarbon radical of less than 10 carbon atoms or hydrogen. An oxyhydro-
carbyl group is a hydrocarbon group or hydrocarbon group having no more than
one heteroatom in the backbone selected from N, S, and 0 for every two carbon
atoms in the backbone, ~herein a hydrogen attached to a carbon atom has
been replaced with
~,;
~.
~3~
a cllvalent oxygen atom to E`orm an external boncl.
For example, starting wlth CH3CH2OCH3, the oxyhydro-
carbyl der:lvcltives itlC lude -O-CH2CH2()CH3. Exemplary
hydrocarbyl groups incLude aromatic gr-oups (e.g~,
phenyl, naphthyl and benzothienyl~ and aliphat:Lc
groups (linear~ branched, or cyclic) lncluding
cyclohexyl, tetrahydrofuryl, dioxanyl, peperidyl,
pyrolidinyl, ethoxyethoxy ethyl, etc.) Preferably,
this oxyhydrocarbyl group has 1 to 10 carbon atoms.
Examples of useful silanes are vinyltriethoxy silanes,
vinyltris(2-methoxyethoxy) silane, vinyltriacetoxysilane,
gamma-methacryloxy-propyltrimethoxy silane, beta-(3,4,
epoxycyclohexyl) ethyltrimethoxy silane and gamma-glycldoxy-
propyltrimethoxy silane. Other useful silanes of this type
15 are known to the art. Combinations of these silanes or ~-
additions to these silanes of compounds copolymerizable with
either functional group of the reactant (silane, epoxy, vinyl
or methacryloxy) is anticipated in the practice of this inven-
tion.
It has been found that the molar ratios of the metal
ester to the reative silane may be varied depending upon the
coating system chosen. For example, in the compositions con~
taining the titanium ester and an epoxy-functional silane,
the molar ratio of metal ester to silane may vary rrom about
1:0.5 to about 1:7 with the most preferred ratio being 1:4.
In compositions containing the titanium ester and acryloxy-
functional silane, the molar ratio may vary from
~ about 1:3 to about 1:15, while the pre~erred molar rat;io
:
:;;.~: i : , ~ ........................ . .
: . ': - . ' ' -
ma~/ vary ~`rom about, 1:3 t,o about, :I:7 w:lt;h the most pref'errecl
rat;io belng ahout, I:ll~ W:ith the compositlons contalnln~
the tltanium ester ancl vinyl-furlcti.onal silane, the useful
molar rat:io of metal ester to s.ilane ls about 1:4~ Other
molar ratios of metal ester to reactive s:Llanes are given
: in Table I.
,
- 6 -
:~ . . , . - , . .
ABI,E' I
Molar Ratio
_ Metal F:,ster to R active Silene
Most
Coating PreferredPreferred
_ _O ~ tion ___ _Usef`ul Range _Ran~ atio
Al-ester/epoxy- 1:1 to 1:5 ]:2 to :L:51:4
functional silane
A1-ester/acryloxy- 1:1 to 1:101:2 to 1:5 1:4
10 functional silane
Zr-ester/epoxy- 1:3.5 to 1:4.5 1:4 1:4
functional silane
Zr-ester/acryloxy- 1:3.5 to 1:4.5 1:4 1:4
functional silane
Various ingredients rnay be incorporated into the
coating compositions, if desired. For example, pigments or
dyes may be incorporated in order to provlded a co~ored
coating. Solvents may be added to the coating cornposition in
order to facilitate the addition of solid metal esters.
Solvents, or other viscosity modifiers, may also be added
to ad~ust the viscosity of the uncured composition. Various
conventional leveling agents may also be added to the coating
composition. These may be useful in producing a high quality
optical grade coating. Furthermore, various accelerators
may be added to the cornpositions in order to speed the curing
process. Fillers and polymeric modifiers may be added.
In order to reduce the viscosity of the coating
compositions in the practice of the invention there may be
added solvents such as the lower alcohols, lower carboxy1ic
- 7
.. ,,:~ ,. . , , ~: .
acids, halogenated hydlocarbon solvents, and aromatlc solvents.
These inclucle ethanol, methanol, tert-butanol~ chloroform,
methy:lene chlor:ide, ace~ic acld, toluene, ben~ene, xylene,
trichloroethane, 1,2-dlchloroethane, etc. Other useful 801 `
vents of the type described are known to t;he art. The amount
of solvent added is dependent upon the particular metal ester
used and the coating viscosity desirecl.
In order to increase the v:Lscosity of the coatlng
compositions there may be added oligomerized siIane in an
amount ranging from 1-20% by weight of said composition. For
example, gamma-methacryloxypropyl-trimethoxysilane which is
prepolymerized by a Pree radical mechanism at 100C~ for about
20 minutes and diluted to a 50% solution in ethyl alcohol is .
useful in increasing the viscosity of the coating composition
by addition thereto.
Leveling agents are also useful in the practice
of the invention in that they level ridges formed in the
coating durlng the coating process. Leveling agents which
have been found useful in the practice of the present invention
include "SF-1023"~, a silicon based surfactant available
from General Electrlc; "FC-430'i* and "FC-431"*, fluorocarbon~
based surfactants available from Minnesota Mining and
Manufacturing Co., etc. Preferably these leveling agents
are present at about 0.3 weight percent of the coating
solution, although more or less may be used if desired. A
preferred leveling agent is 'ISF-1023"*.
l'he coating compositions used in this invention
may be applied to a wide variety of substrates to impart
*trademark
-- 8 --
,
abrasion resl~tance, ;olverlt resLt3tan(e, corros:lon reslstance
and to irnpart -release charclcterlst;icc, to the surface. In
general, the type of` subst;rates that may be coated ln
accordance with -~ s inventlon include rigid and flexible
substrates such as: plastlcs, glass, metal and cerarnics.
For example, soft substrates such as plastics can be rendered
very mar and abrasion resistant ~y the practice of this
invention. Representative examples include: lenses used in
ophthalmic spectacles, sunglasses, optical instruments,
illuminators, watch crystals and the like; plastic window
glazing; signs and decorative surfaces. Metal surfaces can
be rendered resistant to corrosion by the practice of this
invention whereby the brilliance of polish may be maintained
on decorative metal strips and front surface mirrors.
Further, the coating can be colored and be applied to sur~
faces as a paint.
Those substrates to which the coatings of the
invention do not exhibit exce:llent na-tural adhesion may
nevertheless be readily coated in accordance with this
invention, with resultant excellent adhesion thereto, by
first modifying the surface thereof Such modlfying
~echniques include roughening of the surface (e.g., by
mechanical means, by solvent, by chemical etching, oxida-
tion, etc.), and by application to such surface of a con-
ventional priming agents.
The coatings of the present invention may beapplied to a substrate in any desired thickness. It has
been found that coatings Gf between about 3 and 5 microns
- 9 ~
of~er exceLlent l~)r~asion reslstarlce. Mowever, thicker
coatlngs (e.g., up to 20 micl-ons or more) may be obtained
by applying successive layers of the coatlng to the substrate.
Thls may be done by applying a layer of the coating composi-
tion to the substrate and then partially curing lt, forexample, by heating it for about one minute at about 75C.
A second layer of the coating may then be applied. This
procedure may be repeated until the desired coating thickness
is attained. These multiple coatings offer much higher
resistance to abrasion than do single coatings.
Various methods may be employed to cure the
coatings of the present invention. For example, they may be
cured by heat, exposure to ultraviolet light, or exposure to
electron beam radiation. The particular method used is
dependent upon the coating being applied, and the substrate
being coated.
All of the coating compositions will cure when
exposed to heat. However, the exposure conditions may vary
depending upon the coating composition used. For example,
; 20 the vinyl-functional and acryloxy-functional silane~metal
ester coatings require exposure to temperatures between
about 130C. to 170C. and preferably, about 150C~ for
periods of time between about 30 to 60 minutes. Epoxy-
functional silane-metal ester coatings can be cured by
25 exposure to temperatures between 75C. to 100C. for perlods
of time from between about 16 to 40 hours. As the curing
temperature is increased the time necessary to cure the
composition is decreased.
-- 10 --
. ~.
:
It ~las beerl f`ound that; t;he amount Or time necessary
to cure these coat;lngs at t~lese temperatures can be materlally
reduced by the addition of a small amount of an accelerator
to the compos:Ltion. The accelerators have been found useful
in the range of from about 0.4 to about 2.5% by welght of
the coating composition. Accelerators which have been found
useful are the mlneral acids such as hydrochloric, nitric, ~ ~
sulfuric, etc. Other acids which have been found useful ; ~-
include boron trifluoride and aluminum trichloride.
All of the coating compositions containing titanium ;~
.. ~
metal esters will cure when exposed to ultraviolet light. It
is preferable that the irradiation be carried out in an inert
atmosphere such as nitrogen, carbon dioxide, helium, argon,
etc. since oxygen inhibits the reaction. The amount of
tlme necessary to completely cure the coatings varies
inversely with the intensity of the light. For example~ ~
irradiation may be effected by shining a General Eléctric -
275 watt sun lamp through a quartz glass cover into a
nitrogen purged chamber eontaining the coated substrate.
The quartz glass cover allows the passags of ultraviolet
light in the range of about 2,000 to about 4,000 angstroms.
Curing is complete in from 5 to 20 minutes depending upon
the distance from the light source to the substrate.
Vinyl-functional and acryloxy-functional silane-
metal ester coatings w111 also cure when exposed to electron
beam irradiation. It is desirable to carry out the
irradiation in an inert atmosphere such as nitrogen, carbon
dioxide, helium~ argon, etc. ~he amount o~ tlme necessary
~, ''~ .
11 --
to cornpletely cure ~le co~ltlngs varles inver-sely wlth the
power Or the elec~;ron beam ;ource. IrradLation may be
effected, for example, by passing the coated substrate
through a chamber purged w:l~h an lnert gas into whlch a
stream of electrons is directed~ The source of the electron
beams may be a Model CB-150 Elec-tro-Curtain* available from
Energy Sciences, Incorporated, Burlington, Massachusetts.
Typically, the coatings are cured in about 4 seconds.
The unexpected resistance to abrasion exhibited by
the coatings prepared in accordance with the present inventlon
is shown by the Oscillating Abrader Test. This test is
performed on the oscillating abrader apparatus shown in
Figure 1.
The oscillating abrader apparatus 10 comprises
shaker table 14 in housing 12. Table 14 is connected to
motor driven osclllating means via arm 16. Such oscillating
apparatus 10 is commercially available from Eberbach ~-
Corporation as Model 6000. Table 14 oscillates at a frequenoy
of 1.25 cycles per second and a stroke of 3.75 cm.
A coated substrate 18 to be tested is first firmly
fastened to the top of table 14 by means of double coated
`':
tape. Abrasive means 20 is pressed a~ainst the coated
surface 22 of substrate 18 and is anchored to the base
of abrader block 24 by means of double coated tape.
Abrasive means 20 comprises 3/0 grade steel wool. The
base 26 of block 24 is 2.5 cm. by 2.5 cm. and the portion
~trademark
,
- 12 -
~ ' .
of abraslve means 20 whlc~ Ls in pressure-contact wlth surface
22 is there'ore about 2.5 cm. by 2.5 cm. The deslred
abrasive force to be applied is controlled by means of
weights 28 supported o~ rod 30 by means of` rinr 32. Rod 30
is connected to block 24. Weights 28 are maintained directly
above block 24 by means of a suitable bushing 34 held by ~ ;
` arms 36, the bushing permittlng unrestrict;ed vertical move-
ment while preventing horizontal movement of block 24.
Abrasion resistance is measured by fastening a
coated substrate 18 to the top of table 14 as described
above and pressing abrasive means 20 against the coated
surface 22 and applying a predetermined abrasive force by
~: ;
means of weights 28. The oscillating motion of table 11~ is
started. The number of complete oscillations is counted by ;
Z 15 means of counter 38. When 100-cycles (a cycle being one
.~ ~.,; , .
complete forward and back movement) are completed the
oscillating table is stopped and the surface 22 of the coated
substrate 18 is visually inspected for scratches. Weights 28
are then either increased or decreased incrementally and khe
20 procedure is repeated on an unabraded portion of the test -
'sample.
1The maximum weight (including block 24, rod 30,
~ring 32, and weights 28) which can be placed on abrasive
!means 20 without producing visible scratches on the test ;~
125 sample after 100 cycles is recorded. Since the area of the
,ibase of block 24 (and, hence~ the abrasi~e means 20) is one
square inch, the abrasion resistance value can also be
referred to as pounds per square inch. (1 lb/ln =70.4g/cm
~` `:
- 13 -
:
~ .:: ~ , :- . . , :
Adi~es:lorl of` t~le cllred cocltlrlgs to the su~strate
is measure~ by cllt~ing the c~ured, coated surf2ce through
with a sharp edge ln a ser:les of parallel lines about
0.318 cm. apart and t~en with a s:Lmilar series of parallel
; 5 l:Lnes at right angles to the first series, also spaced
; about 0.318 cm. apart. A total of fifty squares are
thereby cut through the cured~ coated substrate. A section
of 'tScotch"~ Brand Magic Transparent Tape No. 810 is firmly
pressed into contact with the coated surface so as to cover
the entire cross-hatched area. The tape is then rapidly
manually stripped from the substrate at a 90angle to it.
Adhesion is rated at 0 to 100 percent. For each square
which is removed durlng the test, the recorded adhesion
value is reduced by 2 percent.
The following examples are meant to illustrate,
but not limit this invention. Parts and percentages are
by weight unless otherwise indicated.
__ __ _
*trademark
_ 14 -
EXAMPL,E 1
_ ___ _
Tetralsopropyl titanate was added to ~amma-meth-
acryloxypropyltrime~loxy silane at a molar ratio of' 1:10 and
mLxed at room temperature. The composition was spin coated
5 onto a sheet o~ polydiallylglycolcarbonate and cured by ;
exposure to ultraviolet light for 15 minutes.
The 3 to 5 micron coating was smooth, clear, trans-
parent, firmly bonded to the substrate and abrasion reslstant.
The experiment was repeated with a mola~ ratio
of 1:4 with comparable results.
EXAMPLES 2 - 8
,
Aluminum isopropoxide (0.1 mole) was heated
(117 - 120C.) to melting and dissolved in 80 g. toluene
heated to 80C. Dlssolution took one-half hour and the
solution was filtered through No. 1 Whatman filter paper.
; The solution was then mîxed with gamma-glycidoxypropyltri-
methoxy silane in the molar ratios shown in Table II, spin
~, i ,
coated onto 5 x 5 x 0.16 cm. sheets of polyallylglycolcar-
bonate and cured for 16 hours at 85C. The cured coatings
.. .
(3 to 5 microns) were clear, smooth, transparent and abrasion
resistant.
. . ,
Table II reports the data for these examples.
:
,j TABLE II
` _ ~ 2 3 4 5 6 7 8
." ~
25 Molar Ratio 1:11:2 1:3 1:4 1:5 1 7 1:10
`, Metal Ester:
i Reactive Silane
,1 Abrasion 10 15 20 25 20 5 0
l Resistance (PSI)
`~ 3 (g/cm ) 704 1056 14081760 1l~08 352
~,
~, .
: . . . - .
5~
EXAMPLES 9 - 18
_ _ _ _ _ _
Aluminum isopropoxlde was dissolved as above and
added to gamma-methacryloxypropyltrlmethoxy sllane. This was
again spin coated onto the carbonate squarles and cured in an
oven ~or 60 m:Lnutes at 150QC. All coatings were clear,
smooth and transparent. Table III shows their abrasion
resistance and adhesion.
TABLE III
Example 9 10 11 12 13 14 15 16 17 18
Molar Ratio 1~ 2 1.3 1:4 1:5 1:7 1:10 1:15 1;20 1:30
Metal Ester:
Reactive
Silane
Abra~ion 12 3 17 25 12 15 12 10 10 7
15 Resistance
(PSI~ ~
Adhesion (%) 100 100 100 100 100 100 100 100 100 100 ~ -
EXAMPLE 19
A 5 cm. x 5 cm. x o.64 cm. sheet of polycarbonate
("Lexan"*~ commercially avallable from General Eleotric) is
washed with absolute ethyl alcohol and then dried with a llnt
free towel. A coating solutlon of the following formula was l;
prepared as described in Example 1.
Tetraisopropyl titanate 2 gm.
Gamma-glycidoxypropyltrimethoxy 3 gm,
silane ,
Gamma-methacryloxypropyltrimethoxy 3 gm. ;~ -
silane 1~
HCl (Goncentrated) 4 drops ;
"SF-1023"* (silicone leveling agent 1 drop
commercially available from
General Electric)
*trademark
,.
- 16 -
The solutlon ~las ;~)In coat;~d ont;o the polycarbonate
and placed :In an oven for l5 minutes at 150C. The cure was
then completed by plac:Lng t;he partIally cured substrate into
a nltrogen purged chamber and exposlng it to ultraviolet
light. The cured coating (approximately 3 to 5 microns
thick) was clear~ smooth~ transparent, firmly bonded to the
substrate, and very abrasion resistant.
EXAMPLES__0 - 29
Coating compositions are prepared by mixing tetra-
isopropyl tltanate with gamma-methacryloxypropyltrimethoxy
silane in a glass beaker at room temperature at various molar
ratios. The resultlng coating compositions are then spin
coated onto polycarbonate and cured as described in Example 19. ;~
The cured coatings (approximately 3 to 5 microns thick) are
~ 15 clear~ smooth, transparent and firmly bonded to the substrate.
; They are also very solvent resistant and very corrosion
resistant. Results of the abrasion test and adhesion test
are shown in Table IV. -~
,
TABLE IV
-~ 20 _E ample 20 21 22 23 24 25 26 27 28 29
`~ Mol~r Ratio 1~ 2 1:3 1:4 1:5 1:7 1:10 1:15 1:20 1:3Q
' Metal Ester:
Reactive
i Silane
Abrasion 2 3 15 3 25 15 lLI 10 9 3
' Resistance
,! ~ (PSI)
Adhesion t%) 100 100 100 100 100 100 100 100 100 100
:
- 17 -
-
,: ~
~ J5~ r p
EXAMPLE~ 30 - 38
Coat:Lng compositiorls are prepared by mixing tetra-
isopropyl titanate wi-th gamma-glycidoxypropyltrimethoxy
silane in a glass beaker at varlous molar ratios at room
temperature. The resultin~ coating compositions are then spin
coated onto polydiallylglycolcarbonate and partially cured by
exposure to ultraviolet light as described in Example 1 for
4 minutes at a distance o~ about 7.5 cm. The cure is then
completed by exposure to 85C. ~or 16 hours. The coatings
were slmilar to previous coatings of this invention. Results
of the abrasion test and adhesion test are shown in Table V. `-
TABLR V
Example _30 _ _31 _3233 34 35 36_ 37 38
Molar Ratio1:0.5 1:1.5 1:4 1:5 1:6 1:10 1:15 1:20 1:30
15 Metal Ester:
Reactive '
` Silanes -
Abrasion 32 3235 20 18 4 6 3 2
Resistance
20 ~PSI) -
Adhesion (%) 100 100 100100100 100 100 100 100
EXAMPLES 39 - 40
Substrates precoated with commercially available
abrasion resistant coatings are obtained and tested for
,
abrasion resistance on the oscillating abrader. The
results are shown in Table VI.
i .
:. ,
;
- 18 - ~
:~ :
... 1 . . ~ . . . . . .
;~a~ tP
TAE~I.E V'[
Example _ 39 4
__~
Coating/substra~e (;eneral Electric du Pont "Abcite"*, -~
"MR-4000"*, an organic a silioon rluoro-
melamine -type coatin~, carbon hard coat,
on "Lexan" Polycar- on polymethyl-
bonate methacrylate
Pressure required 2 10
to abrade (PSI) ~
10 EXAMPLE 41 ;
A 5 cm. x 5 cm. x 0.16 cm. sheet of polydiallyl-
glycolcarbonate is washed with absolute ethyl alcohol and
dried with a lint free towel. A coating composition is pre-
pared in a glass beaker at room temperature and spin coated
onto the substrate. The coating composition comprises:~
,
Tetraisopropyl titanate1.75 gm.
~amma-glycidoxypropyltri-
methoxy silane 6.o gm.
Borontrifluoride ether ; ~`
complex 4.0 drops
Silicone leveling agent
(S~ 1023) 1.0 drop
The coated substrate is partially cured by placing ~;
it into a nitrogen purged chamber and exposlng it to ultra
j ~ 25 violet light as described in Example 1 for 4 minutes at a
~ : :
distance of about 7.5 cm. The cure is oompleted by
exposure to 85C. for 8 hours. The cured coatings
(approximately 3 to 5 microns thick) are clear, smooth,
: '
transparent and firmly bonded to the substrate. The
coating is also very abrasion resistant (exhibitin~ an
__ _ _
~tradernark
- 19 -
.
abrasion resistance o~` 25 P';;r on the osclllating abrad~r),very solvent resistant and very corrosion resistant.
EXA~IPLE. ll2
Z:lrconiun1isopropoxide (33 ~rams) is dissolved in
toluene (167 grams) heated to approximately 75C. The warm
solution is filtered using the Buchner funnel and "No. 1
Whatman" filter paper. A 5 cm. x 5 cm. x 0.16 cm. sheet of'
polydiallylglycolcarbonate is washed with absolute ethyl
alcohol and dried with a lint ~ree towel. A coating composi-
tion is then prepared in a glass beaker at room temperatureand spin coated onto the substrate. The coating composition
comprises: ~ -
Zirconium isopropoxide-toluene 12.0 gms.
solution
I 15 Gamma-methacryloxypropyltri- 6.o gms.
-~ methoxy silane
, Silicone leveling agent (SF 1023) 1.0 drop
The coated substrate is cured by exposure to 140C.
for 60 minutes. The cured coating (approximately 3 to 5
microns thick) is clear, smooth, transparent and is ~irmly
bonded to the substrate. The coating is also abrasion
resistant (exhibiting an abrasion resistance of 12 PSI on the
oscillatlng abrader), very solvent resistant and very corro-
sion resistant.
E _ PLE 43
A 5 cm. x 5 cm. x 0.16 cm. sheet of polymethyl-
methacrylate is washed with absolute ethyl alcohol and
dried with a lint free towel. A coating solution is then
prepared in a glass beaker at room temperature and spin
`~ 30 coated onto the substrate. The coating composition
- 20 -
. .- -
,,
.
~ 9
~, .
comprises:
Tetraiso~ropyl titanate 1.75 gms.
Vlnyl-tris-(2-rnethoxy- 7.0 ~ms.
ethoxy)silane ("A-172~'*
5 commerclally a-vailable
~rom Union Carbide)
The coating is cured by electron beam radiation by
passing the coated substrate through a chamber purged with
nitrogen into which a stream of electron beams ls directed.
The source of the electron beams is a CB-150* Electro-
Curtain available from Energy Sciences, Incorporated3 ~ ~-
Burlington, Massachusetts. The Electro-Curtain is operated
at 10 milliamperes and 150 kilovolts. The coated substrate
is exposed to electron beam radiation for 4 seconds~ The
15 cured coating (a'pproximately 3 to 5 microns thick) ls clear, ;
smooth, transparent and is firmly bonded to~the substrate.
.~ ,
The coating is also abrasion resistant (exhlbiting an
abrasion resistance of 10 to 12 PSI on the oscillating
..
abrader), very solvent resistant and very corrosion resistant~
EXAMPLE 4'4
A coating composition is prepared utilizing
partially hydrolyzed tetraisopropyl titanate. The tetra-
isopropyl titanate is hydrolyzed as follows:
'' a) 4.7 gms. 37% (concentrated) HCL ~-~
is added to 67 gms. absolute ethyl
alcohol.
b) Z8.4 gms. (0.1 mole) tetralso-
propyl titanate is added to the
above solution.
Hydrolysis takes place at room temperature in
about 15 minutes. The following materlals are then
*trademarks
- 21 -
combined at room temperatures lo make the coating solu~iorl:
IIydxoIyzed tetralsopropyl 5.0 gms.
titanate solut;ion
Gamma-methacryloxypropy]- 6.o gms.
5 tr:lmethoxy silane
Silicone leveling agent (SF 1023) 0.26 gms.
EXAMPLE 45
A 5 cm. x 7 cm. x n.16 cm. sheet of aluminum was
cleaned with an abrasive pad and water then washed with
absolute ethanol and dried with a lint free towel. The
coating composition of the previous Example was spin coated
onto the surface of the alumlnum sheet and cured at 150C ;~
for 60 minutes. The cured coating (approximately 3 to 5
microns thick) was clear-~ smooth, transparent, abrasion
resistant and is firmly bonded to khe substrate.
EXAMPLE 4 6 :;
Polyester sheets are etched with a dilute solution
of sulfuric acid in absolute ethyl alcohol. The coating
composition of the previous Example was spin coated onto ;~
20 the etched polyester sheets and cured at 150C. for 60 minutes.
The cured coatings (approximately 3 to 5 microns thick) were
clear, smooth, transparent, abrasion resistant and firmly ;;~
bonded to the substrate.
EXAMP1E 47
Sheets of acrylic resin were pretreated by
a) immersion in chloroform for 2 minutes
b) submerging the substrate in dichloro-
methane (e.g., 30 seconds at 25C.)
c) roughening the surface of the sub-
strate with fine sandpaper (410 through
600 grit polishing paper)
- 22 -
',... . . .
.
r~
d) rollgh(?ning the ~lrl'ace of` the
substrate with alu~inllm oxide
abra~;lve powder, each substrate
was therl
5 coated wlth the ~olut-lon of' t~le previous Example and cured at
150C for 60 minutes.
The cured coatings (approximately 3 to 5 microns ;~
thick) are clear, smooth, transparent, abrasion and solvent
and are f`irmly bonded to ~he substrate.
EXAMPLE 48
A 5 cm. x 5 cm. x 0.16 cm. sheet of polydlallyl-
glycolcarbonate is washed with absolute ethyl alcohol and
~' dried with a lint free towel. A coating solution of the
following formula is prepared as described in Example l.
., ~.
15 Tetraisopropyl titanate 2 gms
~amma-methacryloxypropyl- 6 gms.
trimethoxy silane
Sllicone leveling agent l drop
The coating was then flow coated onto the substrate ;~
and cured by electron beam radiation as described above. The
coating cured ln about 8 seconds. The cured coatlng (approxi-
mately 3 to 5 microns thick) is clear, smooth~ transparent,
`~ abraslon and solvent resistant and was firmly bonded to the
substrate.
EXAMP E 49
- A coating compasition comprising a 1:4 molar ratio
~' of tetraisopropyl titanate to gamma-methacryloxypropyltri- ;
methoxy silane was prepared as described in Example l. The
coating composition was spin coated onto "Lexan" poly-
~` 30 carbonate and cured by exllosure to 150C, for 20 minutes
followed by exposure to ultraviolet light as described
- 23 -
.
in E~ample L ~ol~ l5 InirllJt;~s at; a dist;arlce of about 7.5 cm.
Th~ so:lvent res-lst,ance of` the cured coating was
then checked by forillir~ four l;o f:ive small pools of' solvent
on the coated surface of the substrate, allowing said pools
to remain on said surface for about 20 minutes, wiping said
pools dry, and visually inspecting for damage to the cured
coating. When tested according to this procedure~ t,he cured
coating was unaffected by the following solvents:
a) Water f) Chloroform
b) Ethanol g) Dimethyl formamide
c) Methanol h) HCl (concentrated)
d) Acetone i) Toluene
e) 2-Butanone
EXAMPLE 50
A 10 cm. x 10 cm. x 0.013 cm. sheet of polyester
film was primed with amidized and epoxidized polybutadiene -~
in methanol. A coating composition was then prepared in a
glass beaker at room temperature. The coating comprised: ~ -
Tetraisopropyl titanate 2.0 gms.
Gamma-glycidoxypropyl- 6.o ~ms.
trimethoxy silane
Sllicone leveling agent (SF 1023) 1.0 drop
The coating composition was spin coated onto the
primed substrate and partially cured at 75~C. for 1 minute.
The coated substrate was cooled to room temperature (e.g.,
25C.) and a second layer of the coating composition spin
coated onto the partially cured coating~ The multiple
coating was cured by exposure to 75C. for 16 hours.
- 2~
The c~ured c~oatirllr, (al,)prox:Lmately 8 microns
thlck) is clear, smooth~ ~lex.Lble, transparent and is
firmly bonded to the substrate. The coatLn~ is also very
abrasion reslstant; (exhlbitlnK an abrasion resistance of
20 PSI on the oscll.latln~ abrader), very solvent resistant,
and very corroslon resistant. :
-'
'; ' ~ :~
,', ' '
.. . .
~ .
,
` i :
;~ ;'
.
'
-
~ : - 25 -
.. ~.
. .
.
I~.XA~!~[,[i,~S 5~_
'r~ese examples s~o~ the general usefulnesE; of
various rorms of` metaJ esters having at least two ester
groups per metal atom.
Thirty-six (36.o) grams of gamma-glycidoxypropyl-
trimethoxy silane was split into three portions, A~ B~ and C.
To A was added 5.0 g. Or triethanolamine chelate of bis
titanium isopropoxide ~ .
[(OHC~2CH2)2N]2 Ti(OC3H7)2' ~` ~
10 to B was added 8.5 g. dichlorodialkoxytitanate ~ -
Cl Ti(O(CH ) CH3)2, and
to C was added 8.o g. chlorodibutoxy aluminum solution ~'
Cl Al (O(CH2)3C113)2-
The metal esters of B and C were added as
solutions in methylene chloride comprislng 25% by weight
solids. Two drops of an oligomeric fluorocarbon leveling `~
agent were added as a coating aid.
Coating solution D was made with 6.o g. gamma-gly-
cidoxypropyltrimethoxy silane and 4.5 g. of a polymeric alkyl
titanate having the repeating structure
0 (CH ) CH
2 3 3
~Ti O~
-~CHZ)3cH3
were mixed with one drop of SF1023 (leveling agent).
Sheets of polydialylglycolcarbonate (about 7.7 x ;~
7.7x.16 cm) were washed with absolute ethanol and dried with
lint free tissue. The solutions were applied by spin ~oating
to respective sheets and cured in an oven at 85C. for 16 hours.
- 26 -
~ .. . . - , . : ~
:: . : .. . ,, ., , :. ~ -; :
The cured coat;ings :Ln all cases were smooth,
transparent~ solverlt; resistcln~, and ~ad ~ery good abraslon
resist.ance to 3/0 steel wool.
` "".
.
~ .
. .
