Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
2~3~
ALKENYL ETHERS AND RADIATION CURABLE COMPOSITIONS
According to this invention there i5 provided an
alk-~-enyl ether silicate having the formula (I)
[X]4_nSi[ORlocH=cH-R2]n
' ~ .
wherein X i~ halogen, -OR wherein R is lower alkyl, a
mixture of halogen and -OR, a mixture of -OR and hydrogen :
or a mixture of halogen and hydrogen;
Rl contains from 1 to 8 carbon atoms and is
alkylene, alkenylene, alkynylene, optionally alkoxylated ?
with up to 20 units of
- (CH2cHO) -
wherein Y is hydrogen or methyl, R2 is hydrogen or lower
alkyl and n has a value of from 1 to 4. ~ .
Of the above compounds, those mixtures wherein X ;
contains -OR and wherein R2 is hydrogen atoms, are
preferred and products wherein n has a value of at least 2
are most preferred. Mixtures of the alk-1-enyl ether
~ilicates O:e the present invention can contain varying
amounts of 2 to 4 components where n has a value of 1,2,3
and/or 4. Preferred mixtures are those wherein the
tris(vinyloxyalkylene) alkyl orthosilicate i5 present.
:.. : ~ ' . , : , ~ !
2Q3~
-- 2 --
The products of Formula (I) are prepared according
to the reaction illustrated by the equation:
SitX]4 ~ n HORlOCH~CEiR2 ~ ~x]4-nsitoRlocH~cHR;2]n + n XH
~ilicat~ hydro~ alkenyl ether produ~t by-product. ;~
Suitable examples of silicate reactan~s include
tetrachlorosilane, tetrafluorosilane, tetrabromosilane,
tetramethyl orthosilicate, tetrabutyl orthosilicate,
tetraethyl orthosilicate, tetrapropylyl orthosilicate,
diethyl orthosilicate, dipropyl orthosilicate, tributyl : ~ :
orthosilicate, triethyl orthosilicate, tribromoethyl
orthosilicate, dichlorodiethyl orthosilicate.
Representative hydroxy vinyl ethers which are
suitably employed in the reaction include hydroxybutyl ~` .
vinyl ether, hydroxyethyl vinyl ether, hydroxybutyl ::
prop-1-enyl ether, hydroxyethyl but-1-enyl ether,
hydroxyhexyl vinyl ether, hydroxyethyl 2-butyl hex-l-enyl
ether, hydroxy butenyl vinyl ether, hydroxybutynyl vinyl
ether, hydroxybutynyl-prop-1-enyl ether, hydroxypropynyl
vinyl ether, hydroxybutyl 3-methylprop-1-enyl ether, the
vinyl ether of di-hydroxymethyl cyclohexane and alkoxylated
vinyl ether derivatives of the above having the formula
HORl- ( OCHCH2 ) mOCH--CHR2
where m has a value of from 1 to 20, preferably from 1 to 8
and R1, Y and R2 are as defined above.
- 2 0 3.~
-- 3
The mole ratio of silicate to hydroxylated alkenyl
ether depends on the number of terminal alkenyl groups
desired in the product and the number of halo and or OR
groups in the silicate reactant and is as close to
stoichiometry as is conveniently maintained; although up to
a 10:1 excess of silicate reactant over said stoichiometric
amount is within the scope of this invention.
The reaction is carried out under anhydrous
conditions in the presence of from about 0.01 to about 10
wt. %, preferably from about 0.1 to about 5%, of a base
catalyst based on the alkenyl ether reactant. Catalysts
such as sodium or potassium metals, sodium or potassium
hydroxides, hydrides, alkoxides or salts of the hydroxy
alkenyl ether as well as titanium alkoxide are suitably
employed. When halogenated silicates are employed, the -;
addition of a base is required during the reaction to ~
neutralize any hydrogen halide which is generated as ;
by-product. Suitable bases include sodium hydroxide,
potassium hydroxide, sodium or potassium alkoxides,
pyridine or basic pyridine derivatives, ammonia and amines
such as trimethyl amine, tripropylamine and the like.
The reaction mixture may also be affected in up to
90%, pre~erably not more than 50% suitable inert solvent
such as toluene benzene, methyl ethyl ketone, N-methyl
pyrrolidone, tetrahydrofuran, ethyl acetate, acetonitrile,
and the like. Preferred inert solvents are those having a
boiling point below that of the desired product.
Generally, the reaction is carried out at a
temperature between about 50 and about 200C. for a period
of from about 5 to about 48 hours under from ambient
pressure up to about 500 psi. Preferred reaction
parameters include a ten~perature of between about 100 and
about 120C., a reaction time of from about 10 to 20 hours
and a pressure from atmospheric to about 50 psi.
; . . , , ' ' . ' - , ' ' -
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2~31~1~
High conversion to product is achieved in the
present reaction although a product mixture of mono and
poly substituted silicates is usually obtained. Individual
products can be separated by fractional distillation if
desired. The crude product is separated from base catalyst
by usual methods such as extraction and filtration, and
from solven*, by evaporation under reduced pressure.
A major advantage of the present products is that
they are rapidly curable at ambient temperatures by W and
visible light or other sources of radiation such as an
electron beam, x-ray, laser emissions and the like. They
are also reactive diluents for highly viscous coa~ing
materials, such as acrylates, vinyl ethers, epoxides, and
non-reactive resins, etc., to promote rapid curing and
strong bonding to substrate surfaces. From about 1 to
about 60 wt. %, preferably from about 1 to about 30 wt. %,
of the present alk-1-enyl ether silicates are added to said
acrylates, epoxides and/or vinyl ethers to improve their
curing properties.
In accordance with another aspect of this
invention there is provided a radiation curable, cross
linkable composition containing (a) from about 0~1 to about
5 wt. % of an initiator containing at least 25% of a
cationic initiator, (b) from about 0 to about 60 wt. % of
one or more polymerizable components of the group of a
vinyl ether, epoxide, acrylate or a vinyloxy alkyl urethane
and (c) from about 35 to about 99.9% wt. % of an aliphatic
polyfunctional alkenyl ether having the formula (II)
A[(CH2O)m(Z)rcH=cHR]n
: : . : . ~. .
:~ . : . . , .. : -- - .
- ~ .: , : - . :, .
: ~ : - - :: : . ,~ , - ,
--` 2031~1~
wherein A is a carbon atom, -OOEI=CHR or [C1 to C10
alkyl]4_n; R is C1 to C6 alkyl; Z is C2 to C8
alkyleneoxy; r has a value of from 0 to 6; m has a value of
from 0 to 1 and at least one of r and m has a positive
value; n has a value of from 1 to 4, with the proviso that
m is 0 and n is one when A is -OCH=CHR, n has a value of 2
3 when A is [C1 to Cl0 alkyl]4-n and n has a value
of 4 when A is carbon. ~-
',
Of the above polyfunctional alkenyl ether
compounds, those wherein R is methyl; A is -OCH=CH(lower
alkyl), [lower alkyl]4_n or carbon are preferred. ~ -
Also, when the present alkenyl ether is asymetrical, the
compound most preferably contains at least 35% of the cis
isomer with respect to the trans isomer.
The most preferred compositions are those
containing between about 20% and about 50% of component (b)
and between about 50% and about 80% of component (c) where
R is methyl.
The present polyfunctional alkenyl, preferably
propenyl, ether compounds of Formula (II) are
homopolymerizable resins independently useful as protective
coatings and are also effec~ive cross-linking agents for
polymerizable vinyl ethers having at least 6 carbon atoms
or epoxides such as the divinyl ethers of the
bis(hydroxyethyl) ether of bisphenol A, the divinyl ether
of triethylene glycol, the divinyl ether of ?
dimethylolcyclohexane, vinyloxyalkyl urethanes, e.g.
divinyloxybutyl urethane oligomers, the diglycidyl ether of
bisphenol A and its oligomers, bisphenol A epoxy acrylate
and its oligomers, 3,4-epoxycyclohexyl
methyl-3',4'-epoxycyclohexane carboxylate, the ethers
disclosed in U.S. patents 4,388,450; 4,749,807; 4,775,732
and 4,751,271 and corresponding alkoxylated compounds and
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; : . . .
.
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203~
-- 6 --
similar comonomers in monomeric or oligomeric form having a
number average molecular weight up to about 5,000 or
mixtures of said comonomers and/or copolymers. Such
monomeric or polymeric vinyl ethers, epoxidas, acrylates or
urethanes can be reacted with the polyfunctional alkenyl
ethers of this invention to form a cross-linked copolymeric
product having a high cross-linked density and ~xtremely
high resistance to abrasion and chemical attack.
As stated above, the present polyfunctional
alkenyl ethers, particularly the prop-1-enyl ethers, are
homopolymerizable forming an exceedingly branched
structure. As such, these agents can be used as rigid
coatings on substrates which require an exceptionally high
strength, resistance to abrasion and solvent attack.
Substrates on which the copolymerized or homopolymerized
agent is suitably coated include metal, wood, ceramic,
plastic, leather, paper, glass and the like. The present
composition is coated on the substrate by any convenient
and conventional technique in the desired thickness,
usually in a thickness of between about 0.1 to about 5 ;~
mils.
Instant alkenyl ethers having the structure
C~CH20(Z)rCH=CHR]4 produce homopolymers and
copolymers which are totally etheric in composition and
which have greatly increased surface substantivity and
other advan~ages derived from their poly etheric nature,
such as high UV resistance and the ability to form
hydrogels on exposure to water~
As cross-linking agents, the alkenyl ethers of
this invention can be admixed with the above acrylate,
urethane, epoxide or vinyl ether monomers or their
oligomeric counterparts to effect cross-linking in the
presence of a cationic initiator, such as a triphenyl
sulfonium salt of phosphorous hexafluoride, diphenyl
iodonium salt, a mixture of aromatic complex salts of
~ ' ' : :' -
. ~ . : ~ . : ` .
~- 2~3111~
-- 7
hutyrolactone, a phenyl onium salt or an aryl alkyl onium
salt, etc. The initiators suitable to e~fect
polym~rization reactions of the present invention include
the above named cationic initiators which can be employed
alone or in admixture with a free radical initiator to
provide a hybrid system. Suitable free radical initiators
include 1-hydrocyclohexyl phenyl ketone,
2-hydroxy-2-methyl-1-phenyl-1-propan-1-one,
2,2-dichloro-1-(4-phenoxy- phenyl) ethanone and the like.
When initiator mixtures are employed, the free radical
component can comprise up to 75~, preferably between about
30 and about 70%, of the cationic initiator component. A `
particularly preferred initiator mixture includes between
about 30 wt. % and about 40 wt. % of said butyrolactone and
between about 60 and about 70% of said ketone. The present
initiator mixtures are recommended for blends of (b) and
(c) where component (b) contains an acrylate. The total
amount of initiator employed is generally between about 0.1
and about 5 wt. % with respect to reactant or reactants.
In accordance with this invention, one or more of
the present aliphatic aikenyl ethers can be employed or
blended with one or more of the polymerizable epoxides,
vinyl ethers, acrylates or vinyloxy alkyl urethanes, thus
henefiting from the properties of each monomer in the
blend. Further, it is found that blends of the present
propenyl ether and the divinyl ether of dimethylol
cyclohexane enhance solubilization of the cationic
initiator. Such blends may contain up to about 60%,
preferably from about 20 to about 50% of component (b).
The propenyl ether of component (c) in the present
composition, ser~es not only as a reactant, but also as an
essential diluent for the vinyl ether and/or epoxide which
compounds are highly viscous and difficult to apply as
coatings. Thus, the propenyl ether provides a coatable
composition without the need for extraneous diluents which
in many cases can cause blisters and non-uniformity in the
coating product.
---`` 2~311:l~
The compositions of the present invention are
cured within a period of up to one second by exposure to a
source of radiation, e.g. W light, electron beam, laser
emissions, gamma rays etc. Radiation curing in the present
cationic system takes place at a fast rate, e.g. from about
200 to about 1,000 feet per minute of coated surface or
free formed film, depending upon the intensity and type of
radiation employed. W light radiation dosages at room
temperature of from about loO to about 1500 milli ~/cm2
are effective and dosages of from about 200 to about 600
milli J/cm2 are preferred. Equivalent dosages for curing
are employed when using alternative sources of radiation.
For example, curing with electron beam radiation can be
carried out at between about 0.5 and about 20 Mrads,
preferably between about 1 and about 10 Mrads. Specific
techniques for radiation curing are well known, thus
further amplification is not required.
Since the present propenyl ethers are normally
liquid, they can be directly mixed with the polymerizable
vinyl ether, epoxide or vinyloxy alkyl urethane monomer or
oligomer without further conditioning; however, in certain
cases where dilution is desired, as in cases where higher
molecular weight alkenyl ethers of this invention are
employed as component (c) or where the blend provides a
highly viscous mixtue, the alkenyl ether can be dissolved
in an inert organic solvent such as methyl ethyl ketone,
toluene, a hydrocarbon, acetone, an ether or a halogenated
compound such as methylene chloride. However, dilution
with the above solvents should not exceed 50% when hiyhly
resistant coatings are required.
Alternatively, the alkenyl ether monomer or
oligomer, in the absence of a comonomer can be applied
directly to any of the above substrates and subjected to
radiation for curing under the above conditions to form a
more highly cross-linked homopolymeric protective coating.
,~. ; . , .
., . ~ ' : 1 ': . . ~ ,; .
.
2~3~ 1~4
It should also be understood that the present
compositions can optionally contain minor amounts of
conventional adjuvants such as a surfactant e.g. a
fluorocarbon surfactant such as a mixture of
fluoroaliphatic polymeric esters or a silicane copolymer
surfactant or others. It is also to ~e understood that the
present compositions can be cured thermally or by radiation
induced free radical polymerization; however, an advantage
of this invention is ~he ability to cure the compositions
by cationically induced radiation which avoids the
disadvantages discussed in the foregoing disclosure. It is
to be understood however that concurrent free radical and
cationic induced polymerization using a mixture of such
photoinitiators achieves benefits of this invention and is
recommended where component (b) of the composition is an
acrylate, e.g. bisphenol A epoxyacrylate.
EXAMPLE 1
A one liter round bottomed flask, equipped with a
magnetic stirrer, thermometer, water condenser and dry ice
trap attached to vacuum, was charged with ~38 g. (3.78
moles) of hydroxybutyl vinyl ether, 196 g. (0.94 mole) of
tetraethylorothosilicate and 5 g. of KOH pellets. The
flask was heated to 55-60C. for 4 hours, during which time
40 g. of ethanol by-product was taken off. The vacuum was
then removed and nitrogen gas was introduced. The flask
was then heated to 110C. under ambient pressure. After 12
hours an additional 78 g. of ethanol by-product was
removed.
A. The crude reaction product (463 g.) was flash
distilled. The main fraction (292 g.) distilling at
100-200C. under 3 mm Hg was found to contain 85% tris
(vinyl oxybutyl) ethyl orthosilicate and 15% bis (vinyl
oxybutyl) ethyl orthosilicate.
.:
.. . . . . . .
-~` 2~3~1~4
-- 10 --
B. A separate 50 g. portion of the crude reaction
product was flash distilled at 210C., 1 mm Hg. Analysis
of 47 g. o~ the clear, colorless distillate was identified
as 81.2% tris (vinyl oxybutyl) ethyl orthosilicate, 15.2%
bis (vinyl oxybutyl) diethyl orthosilicate and 0.8~ tetra
(vinyl oxybutyl) orthosilicate.
EXAMPLE 2
A 3-necked 100 ml round bottomed flask, equipped
with a magnetic stirrer, vertical water condenser connected
to vacuum via a trap and nitrogen gas inlet was charged
with 25 g. of the above main fraction (Example IA), 40 g.
of hydroxybutyl vinyl ether and 0.5 g. of KOH. The flask
was heated to 100C. under a blanket of nitrogen for a
period of 5 hours after which the mixture was flash
distilled, unreacted material removed at 100C. under 3 mm
Hg and the remaining distillate collected. The collected
distillate was found to be a mixture of 87% tris (vinyl
oxybutyl ethyl) orthosilicate and 10% tetra (vinyl oxybutyl
ethyl) orthosilicate.
EXAMPLE 3
The main fraction of Example 1 tPart A) was mixed
with an equal weight amount of the diglycidyl eth~r of
bisphenol A ~EPON-828, Shell), 1 part per hundred parts of
resin of a fluorochemical surfactant (FC-430), and 4 parts
per hundrad parts of resin of a cationic photoinitiator
FX-512 at 50C. until a homogeneous low viscosity liquid
was obtained. This mixture was then coated on an aluminum
substrate at a thickness of 1.2 mil. The coated surface
was exposed for less than 1 second to 400 millijoules/cm2
from a mercury vapor lamp. A tack free, film was
produced. Coating properties reported in the following
table were determined immediately after W exposure and
after a post cure at 177C. for 15 minutes.
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-~ 2~31~1~
11 --
TA8LE
After WAfter
Property Exposure Post Cure
Pencil Hardness (AST~ D 3363) < 4B F
% Adhesion (ASTM D 3359) 0 80
Double MEK Rubs 39 >100
Reverse Impact - ~10
Mandrel Bend (in.) (ASTM D 3111) 1/4 3/4
EXAMPLE 4
The mixture described in Example 3 was coated on a
polyester substrate at a thickness of 0.5 mil. The coated
surface was exposed to 400 millijoules/cm2 W light for
less than 1 second and post cured for 2 hours at 50C.
Chemical resistance was tested by the covered spot test
(ASTM D 130~). No attack was observed after 24 hours
exposure to 1% H2SO4, 1% NaOH, 10% acetic acid, or
distilled water.
EXAMPLE 5
The mixture described in Example 3 was coated on
an aluminum panel at a thlckness of 0.25 mil. The coated
surface was exposed to an electron beam dosage of 3 Mrads
for less than 1 second to produce a tack free film. Coating
properties reported in the following Table were determined
immediately after electron beam exposure and after a post
cure at 150C. for 15 minutes.
-.~ 2~3~
- 12 -
TABLE
Property After EB Post Cured
Pencil Hardness HB H
% Adhesion 100 100
MEK Double Rubs 2 18
Mandrel E3end 1/~ 1/8
EXAMPLE 6
The main fraction of Example 1 part A (2500 gm)
was mixed with the divinyl ether of triethylene glycol
(25.0 gm~ a bisphenol A epoxy acrylate oligomer
(EBECRYL-3700, Radcure Specialties, 50.0 gm), 2 phr*
cationic photoinitiator (FX 512), 2 phr* free radical
photoinitiator (IRGACURE-184) and 1 phr* fluorochemical
surfactant (FC-430) at 50C. until a homogeneous low
viscosity liquid was obtained. this mixture was then
coated on a polyester substrate at a thickness of 0.5 mil.
The coated surface was exposed to 400 millijoules/cm2
from a mercury vapor lamp for less than 1 second. A tack
free coating with the following properties was produced.
Pencil Hardness 2H
Adhesion 100%
Double MEK Rubs >100
* parts/100 parts resin
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: . , . . . . . . . . . -
: :: - . : : :-. ~ . : .
:~.: ~ :: . . . . ..
.. . . . . . . . . .
r- 203~114
EXAMPLE 7
The main fraction from Example l part A ~6.20 gm)
was mixed with the divinyl ether of triethylene glycol
(18.8 gm) and a divinyl ether urethane oligomer ~prepared
as described in the Degree Thesis o~ Lennart Carlsson,
Dept. of Polymer Technology, The Royal Institute of
Technology, Stockholm Sweden, 19~7; 25.0 gm); 4 phr
cationic photoinitiator (F~-512), and 1 phr fluorochemical
surfactant (FC-430) at 50C. until a homogeneous low
viscosity liquid was obtained. This mixture was then
coated on a aluminum panel (0.25 mil) and exposed to 400
millijoules/cm2 from a mercury vapor lamp for less than 1
second. A tack free coating with the following properties
was produced
Pencil Hardness 3B
Mandrel Bend 3/16 inch
Double MEK Rubs 11
EXAMPLE 8
Into an amber bottle, 50 wt. % of diprop-l-enyl
ether of diethylene glycol (70% cis, cis) and 50 wt. % of a
diglycidyl ether of bisphenol A were charged and mixed at
50C. ~or 1 hour. To this mixture, 2 parts/hundred parts
of the triphenyl sulfonium salt of hexafluorophosphate were
added with agitation. The resulting low viscosity liquid
was directly coated on an aluminum panel in a thickness of
0.15 mil. The coated substrate was then exposed for less
than one second at room temperature to 400 milli J/cm2
radiation from a medium pressure mercury vapor lamp; after
which the substrate having a highly crosslinked strongly
ad~esive coating* was removed. The coating is resistant to
attack by methyl ethyl ketone and is abrasion resistant.
* by Cross Hatch Tape test ASTM 3359
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- 14 -
EXAMPLE ~
A two mil thick layer of a mixture of g8 wt. % of
the tetraprop-1-enyl ether of pentaerythritol and 2.0 wt.
o~ the triphenyl sulfonium salt of hexafluorophosphate is
applied to a polyester substrate. The coated layer is then
crosslinked by exposure for about one second at room
temperature to electron beam radiation at a dosage of 3
Mrad. The resulting highly crosslinked polymer exhibits
strong adhesion, is highly resistant to chemical attack and
has superior abrasion resistant properties.
EXAMPLE 10 -
A. Into an amber bottle, 50 grams of
substantially pure (>95~) cis, cis dipropenyl ether of
triethylene glycol, 50 grams of a diglycidyl ether of
bisphenol A, 2 grams of the triphenyl sulfonium salt of
hexafluorophosphate and 1 yram fluorocarbon surfactant were
charged and thoroughly mixed. The resulting liquid mixture
was coated on an aluminum panel with a ~3 coating rod.
B. The above procedure was repeated except that a
mixture of 48% cis, cis, 42% cis, trans mixture and 10%
trans, trans was substituted for the cis, cis reactant in
A.
C. The procedure in part A was repeated except
that 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexane
carboxylate was substituted for the dipropenyl ether.
Each of the samples A, B, and C were coated in a
thickness of 0.11-0.15 mil on an aluminum panel and then
cured by exposure to W light as described in Example 8.
The cured coatings were evaluated and the results are
reported in the following Table.
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~31114
~ 16 -
It will be appreciated from the above results that
changing the distribution from cis isomer to a cis/trans
isomeric mixture did not materially affect the properties
of the final coating. Example 10 also demonstrates the
high cure speed of the di-propenyl ethers as compared to
the di-epoxy compound.
E~AMPLE 11
A. Into an amber bottle, 50 grams of
substantially pure (>95%) cis,cis- dipropenyl ether of
triethylene glycol, 50 grams of a bisphenol A epoxy
acrylate oligomer, 1 gram silicone surfactant, 1 gram
cationic photoinitiator and 1.5 gm free radical initiator
were charged and mixed at 50C. until homogeneous. The
resulting liquid was coated on polyester using a #6 coating
rod (approx. 0.5 mil) and cured by an exposure for less
than 1 second at room temperature to 400 millijoules/cm2
from a W lamp.
~ . The above procedure A was repeated except that
the free radical initiator was omitted from the
formulation.
C. The procedure in part A was repeated except
that the cationic initiator was omitted from the
formulation.
The cured coatings were evaluated immediately
after W exposure and the results are reported in the
following Table. ~ ~
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17 -
TABLE >
Formula A _ B C
Result tac~ freetack free wet
Adhesion 100%100% none
Double ~EK Rubs >loO 89 none
Pencil Hardness F F none
This example illustrates the necessity of the
cationic photoinitiator and the superior solvent resistance
obtained using a cationic and free radical initiator.
, :
EXAMPLE 12 ~
. , - .
A. Example llA is repeated except that the 50
grams of cis,cis- dipropenyl ether of triethylene glycol is
replaced with 50 grams of a 1 to 1 wt. % blend of cis,cis- -~
dipropenyl ether of triethylene glycol and the divinyl
ether of 1,4-cyclohexane dimethanol.
B. Example llA is repeated except that the 50
grams of cis,cis- dipropenyl ether of triethylene glycol is ~ -
replaced with 50 grams of the divinyl ether of
1,4-cyclohexane dimethanol. The cationic initiator failed
to dissolve in the absence of the propenyl ether and an in
compatible mixture was formed.
The above cured coatings were compared with that
of llA and were evaluated immediately after W exposure.
The results are as reported in the following table.
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--~` 2~114
- 18 -
TABLE
Formula 4 A 5 A 5 B
Adhesion 100% 100%incompatible
Double MEK Rubs >loO >100 none
Pencil Hardness ~ 2H none
This example illustrates that coating hardness can
be significantly improved by adding the divinyl ether of
1,4-cyclohexane dimethanol; and that, the dipropenyl ether
of triethylene glycol is needed to insure compatibility.
EXAMiPLE 13
Into an amber bottle, 50 grams of >95% cis, cis-
dipropenyl ether of triethylene glycol, 50 grams of a
divinyl ether of urethane oligomer (prepared as described
in the Degree Thesis of Lennart Carlson, Dept. of Polymer
Technology, the Royal Institute of Technology, Stockholm,
Sweden, 1987), 4 phr* cationic photoinitiator, and 1 phr
fluorochemical surfactant were charged and mixed at 50C.
until homogeneous. The resulting liquid was coated on an ~ ;
aluminum panel to a 0.25 mil thickness using a #3 coating ;
bar and then cured as described in Example 11. A tack
free coating with the following properties was produced
Pencil Hardness 3B
Mandrel Bend 3/16 inch
Double MEK rubs 5
* parts/100 parts resin
. . .
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