U.S. patent application number 14/663825 was filed with the patent office on 2015-11-12 for toughened cyanoacrylate compositions.
The applicant listed for this patent is Henkel lP & Holding GmbH. Invention is credited to Shabbir Attarwala, Rosa Matilde Davila, Roger James Grismala, Ling Li, Benjamin M. Surowiecki, JR., Stan Wojciak.
Application Number | 20150322295 14/663825 |
Document ID | / |
Family ID | 37637496 |
Filed Date | 2015-11-12 |
United States Patent
Application |
20150322295 |
Kind Code |
A1 |
Attarwala; Shabbir ; et
al. |
November 12, 2015 |
TOUGHENED CYANOACRYLATE COMPOSITIONS
Abstract
This invention relates to cyanoacrylate-containing compositions
that include, in addition to the cyanoacrylate component, a rubber
toughening component, which is substantially clear and colorless
and which is substantially free of release agents and anti-oxidants
known to impair the fixture speeds and shelf life stability of
cyanoacrylate compositions to which they are added. As a result,
the inventive rubber cyanoacrylate adhesive compositions
demonstrate improved properties, such as fixture speed, strength
and shelf life under accelerated aging conditions.
Inventors: |
Attarwala; Shabbir;
(Simsbury, CT) ; Davila; Rosa Matilde; (Sabana
Grande, PR) ; Surowiecki, JR.; Benjamin M.;
(Cheshire, CT) ; Wojciak; Stan; (New Britain,
CT) ; Grismala; Roger James; (Enfield, CT) ;
Li; Ling; (Glastonbury, CT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Henkel lP & Holding GmbH |
Duesseldorf |
|
DE |
|
|
Family ID: |
37637496 |
Appl. No.: |
14/663825 |
Filed: |
March 20, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11995043 |
Jan 8, 2008 |
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PCT/US06/27031 |
Jul 11, 2006 |
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14663825 |
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60698111 |
Jul 11, 2005 |
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Current U.S.
Class: |
156/330.9 ;
522/116; 524/105; 524/112; 524/320; 524/533; 525/295 |
Current CPC
Class: |
B32B 37/12 20130101;
C09J 11/04 20130101; C08K 3/36 20130101; C08K 5/3415 20130101; C09J
2433/00 20130101; C08K 5/092 20130101; C09J 9/00 20130101; C09J
123/0869 20130101; C09J 4/06 20130101; C09J 123/0869 20130101; B32B
2307/558 20130101; C08L 2666/02 20130101; C08K 5/1539 20130101;
C09J 5/00 20130101; C08F 222/32 20130101; C08K 5/159 20130101; C08K
3/04 20130101; C08K 5/10 20130101; C08L 2666/02 20130101; C09J
11/06 20130101 |
International
Class: |
C09J 4/06 20060101
C09J004/06; B32B 37/12 20060101 B32B037/12; C09J 11/04 20060101
C09J011/04; C09J 5/00 20060101 C09J005/00; C09J 9/00 20060101
C09J009/00; C09J 11/06 20060101 C09J011/06 |
Claims
1. A rubber toughened cyanoacrylate adhesive composition,
comprising: (a) a cyanoacrylate component, and (b) a rubber
toughening agent consisting essentially of (a) reaction products of
the combination of ethylene, methyl acrylate and monomers having
carboxylic acid cure sites, and (b) combinations of (a) and
dipolymers of ethylene and methyl acrylate, being substantially
free of release agents, anti-oxidants, stearic acid and/or
polyethylene glycol ether wax.
2. The composition according to claim 1, further comprising a
filler.
3. The composition according to claim 2, wherein the filler is
selected from the group consisting of carbon black, silica and
combinations thereof.
4. The composition of claim 1, further comprising a stabilizing
amount of an acidic stabilizer and a free radical inhibitor.
5. The composition of claim 1, wherein the concentration of the
rubber toughening agent is from about 1.5% to about 20% by
weight.
6. The composition according to claim 1, wherein the cyanoacrylate
component is selected from materials within the structure
H.sub.2C.dbd.C(CN)--COOR, wherein R is selected from C.sub.1-15
alkyl, alkoxyalkyl, cycloalkyl, alkenyl, aralkyl, aryl, allyl and
haloalkyl groups.
7. The composition according to claim 1, wherein the cyanoacrylate
component comprises ethyl-2-cyanoacrylate.
8. The composition according to claim 1, further comprising an
accelerator component selected from the group consisting of
calixarene, oxacalixarene, silacrown, cyclodextrin, crown ether,
poly(ethyleneglycol)di(meth)acrylate, ethoxylated hydric compound,
and combinations thereof.
9. The composition according to claim 8, wherein the calixarene is
tetrabutyl tetra[2-ethoxy-2-oxoethoxy]calix-4-arene.
10. The composition according to claim 8, wherein the crown ether
is selected from members within the group consisting of 15-crown-5,
18-crown-6, dibenzo-18-crown-6,
benzo-15-crown-5-dibenzo-24-crown-8, dibenzo-30-crown-10,
tribenzo-18-crown-6, asym-dibenzo-22-crown-6, dibenzo-14-crown-4,
dicyclohexyl-18-crown-6, dicyclohexyl-24-crown-8,
cyclohexyl-12-crown-4, 1,2-decalyl-15-crown-5,
1,2-naphtho-15-crown-5, 3,4,5-naphtyl-16-crown-5,
1,2-methyl-benzo-18-crown-6, 1,2-methylbenzo-5,
6-methylbenzo-18-crown-6, 1,2-t-butyl-18-crown-6,
1,2-vinylbenzo-15-crown-5, 1,2-vinylbenzo-18-crown-6,
1,2-t-butyl-cyclohexyl-18-crown-6, asym-dibenzo-22-crown-6, and
1,2-benzo-1,4-benzo-5-oxygen-20-crown-7 and combinations
thereof.
11. The composition according to claim 8, wherein the
poly(ethyleneglycol)di(meth)acrylate is within the following
structure: ##STR00009## wherein n is greater than 3.
12. The composition according to claim 1, further comprising
additives selected from the group consisting of shock resistant
additives, thixotropy conferring agents, thickeners, dyes, thermal
degradation resistance enhancers, and combinations thereof.
13. The composition according to claim 12, wherein the shock
resistant additive is citric acid.
14. Reaction products of the composition according to claim 1.
15. A method of bonding together two substrates, comprising the
steps of: applying a cyanoacrylate-containing adhesive composition
according to claim 1, to at least one of the substrates and mating
together the substrates for a time sufficient to permit the
adhesive to fixture.
16. A method of preparing a cyanoacrylate-containing composition
according to claim 1, comprising the steps of: providing a
cyanoacrylate component, and combining therewith with mixing a
rubber toughening agent consisting essentially of (a) reaction
products of the combination of ethylene, methyl acrylate and
monomers having carboxylic acid cure sites, (b) dipolymers of
ethylene and methyl acrylate, and combinations of (a) and (b), and
being substantially free of release agents, anti-oxidants, stearic
acid and/or polyethylene glycol ether wax.
17. The composition according to claim 1, further comprising a
metallocene and a photoinitiator.
18. The composition according to claim 1, further comprising at
least two of citric acid, phthalic anhydride and crown ether.
19. The composition according to claim 1, further comprising a
thermal degradation resistance enhancer selected from the group
consisting of maleimide compounds mono, poly or hetero aromatic
compounds characterized by at least three substitutions on an
aromatic ring thereof, two or more of which being electron
withdrawing groups, quinoid compounds, sulfur-containing compounds,
cyclic sultanate naphthosultone compounds substituted with at least
one strong electron withdrawing group at least as strongly electron
withdrawing as nitro, alkylating agents, silylating agents, and
combinations thereof.
20. The composition according to claim 19, wherein the thermal
degradation resistance enhancer is selected from the group
consisting of N,N'-meta-phenylene bismaleimide, an anhydrosulfite,
a sulfoxide, a sulfite, a sulfonate, a methanesulfonate, a
p-toluenesulfonate, polyvinyl benzyl chloride, 4-nitrobenzyl
chloride, and combinations thereof.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to cyanoacrylate compositions that
include, in addition to the cyanoacrylate component, a rubber
toughening component, which is substantially clear and colorless
and which is substantially free of release agents and anti-oxidants
known to impair the fixture speeds and shelf life stability of
cyanoacrylate compositions to which they are added. As a result,
the inventive rubber toughened cyanoacrylate compositions
demonstrate improved properties, such as fixture speed, strength
and shelf life under accelerated aging conditions.
[0003] 2. Brief Description of Related Technology
[0004] Cyanoacrylate adhesive compositions are well known, and
widely used as quick setting, instant adhesives with a wide variety
of uses. See H. V. Coover, D. W. Dreifus and J. T. O'Connor,
"Cyanoacrylate Adhesives" in Handbook of Adhesives, 27, 463-77, I.
Skeist, ed., Van Nostrand Reinhold, New York, 3rd ed. (1990). See
also G. H. Millet, "Cyanoacrylate Adhesives" in Structural
Adhesives: Chemistry and Technology, S. R. Hartshorn, ed., Plenun
Press, New York, p. 249-307 (1986).
[0005] U.S. Pat. No. 4,440,910 (O'Connor) pioneered rubber
toughened cyanoacrylate compositions through the use of certain
organic polymers as toughening additives that are elastomeric,
i.e., rubbery, in nature. The '910 patent is thus directed to and
claims a curable adhesive comprising a substantially solvent-free
mixture of: (a) a cyanoacrylate ester, and (b) about 0.5% to about
20% by weight of an elastomeric polymer. The elastomeric polymer is
selected from elastomeric copolymers of a lower alkene monomer and
(i) acrylic acid esters, (ii) methacrylic acid esters or (iii)
vinyl acetate. More specifically, the '910 patent notes that as
toughening additives for cyanoacrylates, acrylic rubbers; polyester
urethanes; ethylene-vinyl acetates; fluorinated rubbers;
isoprene-acrylonitrile polymers; chlorosulfinated polyethylenes;
and homopolymers of polyvinyl acetate were found to be particularly
useful.
[0006] The elastomeric polymers are described in the '910 patent as
either homopolymers of alkyl esters of acrylic acid; copolymers of
another polymerizable monomer, such as lower alkenes, with an alkyl
or alkoxy ester of acrylic acid; and copolymers of alkyl or alkoxy
esters of acrylic acid. Other unsaturated monomers which may be
copolymerized with the alkyl and alkoxy esters of acrylic include
dienes, reactive halogen-containing unsaturated compounds and other
acrylic monomers such as acrylamides.
[0007] One group of elastomeric polymers are copolymers of methyl
acrylate and ethylene, manufactured by DuPont, under the name of
VAMAC, such as VAMAC N123 and VAMAC B-124. VAMAC N123 and VAMAC
B-124 are reported by DuPont to be a master batch of
ethylene/acrylic elastomer.
[0008] Henkel Corporation (as the successor to Loctite Corporation)
has sold for a number of years since the filing of the '910 patent
rubber toughened cyanoacrylate adhesive products under the
tradename BLACK MAX, which employ as the rubber toughening
component the DuPont materials called VAMAC B-124 and N123. In
addition, Henkel has sold in the past clear and substantially
colorless rubber toughened cyanoacrylate adhesive products, namely,
LOCTITE 4203, 4204 and 4205, which employ as the rubber toughening
component the DuPont material, VAMAC G. While VAMAC G contains no
fillers to provide color or stabilizers, it does contain processing
aids. These processing aids--or release systems--are reported to be
ARMEEN 18D and stearic acid in combination with GAFAC RL-210 (or
with VANFRE UN, ZELEC UN or SERVOXYL VPAZ-100). In addition, it is
believed that polyethylene glycol ether wax is also used as a
processing aid. Waxes such as this interfere with the physical
properties of cyanoacrylate compositions.
[0009] VAMAC VCS rubber appears to be the base rubber, from which
the remaining members of the VAMAC product line are compounded.
VAMAC VCS is a reaction product of the combination of ethylene,
methyl acrylate and monomers having carboxylic acid cure sites,
which once formed is then substantially free of processing aids
such as the release agents octadecyl amine, complex organic
phosphate esters and/or stearic acid, and anti-oxidants, such as
substituted diphenyl amine.
[0010] Recently, DuPont has provided to the market under the trade
designation VAMAC VMX 1012 and VCD 6200, which are rubbers made
from ethylene and methyl acrylate. It is believed that the VAMAC
VMX 1012 rubber possesses little to no carboxylic acid in the
polymer backbone. Like the VAMAC VCS rubber, the VAMAC VMX 1012 and
VCD 6200 rubbers are substantially free of processing aids such as
the release agents octadecyl amine, complex organic phosphate
esters and/or stearic acid, and anti-oxidants, such as substituted
diphenyl amine, noted above.
[0011] Thus, notwithstanding the state-of-the-technology and the
commercial success experienced by Henkel Corporation with its line
of rubber toughened cyanoacrylate adhesive products (such as
LOCTITE BLACK MAX 380 and 480 and LOCTITE 4203, 4204 and 4205), it
would be desirable to provide a substantially clear and colorless
rubber toughened cyanoacrylate composition, which demonstrates
improved fixturing speed and shelf life stability compared to known
rubber toughened cyanoacrylates.
SUMMARY OF THE INVENTION
[0012] The present invention is thus directed to a rubber toughened
cyanoacrylate adhesive composition, which includes beyond the
cyanoacrylate component, a rubber toughening component having (a)
reaction products of the combination of ethylene, methyl acrylate
and monomers having carboxylic acid cure sites, (b) dipolymers of
ethylene and methyl acrylate, and combinations of (a) and (b),
which once the reaction products and/or dipolymers are formed are
then substantially free of processing aids, such as the release
agents octadecyl amine (reported by DuPont to be available
commercially from Akzo Nobel under the tradename ARMEEN 18D),
complex organic phosphate esters (reported by DuPont to be
available commercially from R.T. Vanderbilt Co., Inc. under the
tradename VANFRE VAM), stearic acid and/or polyethylene glycol
ether wax, and anti-oxidants, such as substituted diphenyl amine
(reported by DuPont to be available commercially from Uniroyal
Chemical under the tradename NAUGARD 445).
[0013] The processing aids and anti-oxidants used to compound
reactions products of these components are typically found in the
VAMAC acrylic rubbers available from DuPont, such as VAMAC G or
VAMAC B-124. These VAMAC acrylic rubber products when used together
with cyanoacrylates have a tendency to destabilize the
cyanoacrylate on the one hand (thus resulting in a shorter shelf
life as the cyanoacrylate becomes more reactive) and to retard
fixture speed on the other hand. Neither of these affects are
particularly desirable.
[0014] While LOCTITE 4203, 4204 and 4205 are each substantially
clear and colorless rubber toughened cyanoacrylate adhesive
products made with VAMAC G, the presence of the release agents and
anti-oxidants in the VAMAC product, sometimes leads to the adverse
affects noted in the preceding paragraph.
[0015] The inclusion of the rubber toughening agent noted above
that is not compounded with such release agents and anti-oxidants
into a cyanoacrylate composition provides for demonstrated improved
properties, such as fixture speeds, shear strengths, fracture
toughness and shelf life, when compared to the BLACK MAX products
or LOCTITE 4203, 4204 and 4205, and at least comparable fixture
speeds and shelf life when compared to non-rubber toughened,
thickened cyanoacrylate adhesive products, such as LOCTITE PRISM
401.
[0016] In another aspect of this invention, a radiation-curable
composition is provided which includes a cyanoacrylate component or
a cyanoacrylate-containing formulation, a metallocene component, a
photoinitiator, and a rubber toughening component comprising (a)
reaction products of the combination of ethylene, methyl acrylate
and monomers having carboxylic acid cure sites, (b) dipolymers of
ethylene and methyl acrylate, and combinations of (a) and (b),
which once the reaction products and/or dipolymers are formed are
then substantially free of processing aids, such as the release
agents octadecyl amine, complex organic phosphate esters, stearic
acid and/or polyethylene glycol ether wax, and anti-oxidants, such
as substituted diphenyl amine.
[0017] This invention is also directed to a method of bonding
together two substrates, which method includes applying to at least
one of the substrates a composition as described above, and
thereafter mating together the substrates. The method, when using
the radiation-curable composition as so defined, may be used where
at least one of the substrates is substantially transmissive to the
radiation used to cure the composition.
[0018] In addition, the present invention is directed to reaction
products of the inventive compositions.
[0019] Also, the invention is directed to a method of preparing the
inventive compositions.
[0020] And the invention is directed to a method of conferring one
or more of the following properties to rubber toughened
cyanoacrylate compositions improved shelf life, fixture speed,
improved shear strength development over time, and improved side
impact strength and fracture toughness, which method includes the
steps of providing a cyanoacrylate composition, providing a rubber
toughening agent of (a) reaction products of the combination of
ethylene, methyl acrylate and monomers having carboxylic acid cure
sites or (b) dipolymers of ethylene and methyl acrylate (or
combinations thereof), and being substantially free of processing
acids and/or anti-oxidants, and mixing together the cyanoacrylate
compositions and rubber toughening agents.
[0021] The invention will be more fully understood by a reading of
the section entitled "Detailed Description of the Invention", which
follows.
BRIEF DESCRIPTION OF THE FIGURES
[0022] FIG. 1 depicts a plot of the development of lap shear
strength overtime for an invention composition compared with two
control products on aluminum substrates.
[0023] FIG. 2 depicts a plot of the development of lap shear
strength overtime for an invention composition compared with two
control products on steel substrates.
[0024] FIG. 3 depicts a plot of the development of lap shear
strength overtime for an invention composition compared with two
control products on polyvinyl chloride substrates.
DETAILED DESCRIPTION OF THE INVENTION
[0025] As noted above, this invention is directed to a rubber
toughened cyanoacrylate adhesive composition, which includes beyond
the cyanoacrylate component, a rubber toughening component having
(a) reaction products of the combination of ethylene, methyl
acrylate and monomers having carboxylic acid cure sites, (b)
dipolymers of ethylene and methyl acrylate, and combinations of (a)
and (b), which once the reaction products and/or dipolymers are
formed are then substantially free of processing aids, such as
octadecyl amine (reported by DuPont to be available commercially
from Akzo Nobel under the tradename, ARMEEN 18D), complex organic
phosphate esters (reported by DuPont to be available commercially
from R.T. Vanderbilt Co., Inc. under the tradename, VANFRE VAM),
stearic acid and/or polyethylene glycol ether wax and
anti-oxidants, such as substituted diphenyl amine (reported by
DuPont to be available commercially from Uniroyal Chemical under
the tradename NAUGARD 445).
[0026] The cyanoacrylate component includes cyanoacrylate monomers
which may be chosen with a raft of substituents, such as those
represented by H.sub.2C.dbd.C(CN)--COOR, where R is selected from
C.sub.1-15 alkyl, alkoxyalkyl, cycloalkyl, alkenyl, aralkyl, aryl,
allyl and haloalkyl groups. Desirably, the cyanoacrylate monomer is
selected from methyl cyanoacrylate, ethyl-2-cyanoacrylate, propyl
cyanoacrylates, butyl cyanoacrylates (such as
n-butyl-2-cyanoacrylate), octyl cyanoacrylates, allyl
cyanoacrylate, .beta.-methoxyethyl cyanoacrylate and combinations
thereof. A particularly desirable one is ethyl-2-cyanoacrylate.
[0027] The cyanoacrylate component should be included in the
compositions in an amount within the range of from about 50% to
about 98% by weight, with the range of about 75% to about 95% by
weight being desirable, and about 85 to about 90% by weight of the
total composition being particularly desirable.
[0028] The rubber toughening component is a reaction product of the
combination of ethylene, methyl acrylate and monomers having
carboxylic acid cure sites, which once formed is then substantially
free of processing aids and anti-oxidants. The processing aids are
release agents such as octadecyl amine (reported by DuPont to be
available commercially from Akzo Nobel under the tradename ARMEEN
18D), complex organic phosphate esters (reported by DuPont to be
available commercially from R.T. Vanderbilt Co., Inc. under the
tradename VANFRE VAM), stearic acid and/or polyethylene glycol
ether wax. The anti-oxidant is a substituted diphenyl amine
(reported by DuPont to be available commercially from Uniroyal
Chemical under the tradename NAUGARD 445).
[0029] Alternatively, the rubber toughening component is a
dipolymer of ethylene and methyl acrylate, which once formed is
then substantially free of processing aids and anti-oxidants. Of
course, the rubber toughening component may be a combination of the
reaction product of the preceding paragraph and the dipolymer of
this paragraph.
[0030] The rubber toughening component should be present in a
concentration of about 1.5% to about 20% by weight, such as about
5% to about 15% by weight, with about 8% to about 10% being
particularly desirable.
[0031] A variety of organometallic materials are also suitable for
use herein. Those materials of particular interest herein may be
represented by metallocenes within structure I:
##STR00001##
where R.sub.1 and R.sub.2 may be the same or different and may
occur at least once and up to as many four times on each ring in
the event of a five-membered ring and up to as many as five times
on each ring in the event of a six-membered ring;
[0032] R.sub.1 and R.sub.2 may be selected from H; any straight- or
branched-chain alkyl constituent having from 1 to about 8 carbon
atoms, such as CH.sub.3, CH.sub.2CH.sub.3,
CH.sub.2CH.sub.2CH.sub.3, CH(CH.sub.3).sub.2, C(CH.sub.3).sub.3 or
the like; acetyl; vinyl; allyl; hydroxyl; carboxyl;
--(CH.sub.2).sub.n--OH, where n may be an integer in the range of 1
to about 8; --(CH.sub.2).sub.n--COOR.sub.3, where n may be an
integer in the range of 1 to about 8 and R.sub.3 may be any
straight- or branched-chain alkyl constituent having from 1 to
about 8 carbon atoms; H; Li; Na; or --(CH.sub.2).sub.n', where n'
may be an integer in the range of 2 to about 8;
--(CH.sub.2).sub.n--OR.sub.4, wherein n may be an integer in the
range of 1 to about 8 and R.sub.4 may be any straight- or
branched-chain alkyl constituent having from 1 to about 8 carbon
atoms; or --(CH.sub.2).sub.n--N.sup.+(CH.sub.3).sub.3 X.sup.-,
where n may be an integer in the range of 1 to about 8 and X may be
Cl.sup.-, Br.sup.-, I.sup.-, ClO.sub.4.sup.- or BF.sub.4.sup.-;
[0033] Y.sub.1 and Y.sub.2 may not be present at all, but when at
least one is present they may be the same or different and may be
selected from H, Cl.sup.-, Br.sup.-, I.sup.-, cyano, methoxy,
acetyl, hydroxy, nitro, trialkylamines, triaryamines,
trialkylphospines, triphenylamine, tosyl and the like;
[0034] A and A' may be the same or different and may be C or N;
[0035] m and m' may be the same or different and may be 1 or 2;
and
[0036] M.sub.e is Fe, Ti, Ru, Co, Ni, Cr, Cu, Mn, Pd, Ag, Rh, Pt,
Zr, Hf, Nb, V, Mo and the like.
[0037] Of course, depending on valence state, the element
represented by M.sub.e may have additional ligands--Y.sub.1 and
Y.sub.2--associated therewith beyond the carbocyclic ligands
depicted above (such as where M.sub.e is Ti and Y.sub.1 and Y.sub.2
are Cl.sup.-).
[0038] Alternatively, metallocene structure I may be modified to
include materials such as:
##STR00002##
where R.sub.1, R.sub.2, Y.sub.1, Y.sub.2, A, A', m, m' and M.sub.e
are as defined above. A particularly desirable example of such a
material is where R.sub.1 and R.sub.2 are each H; Y.sub.1 and
Y.sub.2 are each Cl; A and A' are each N; m and m' are each 2 and
M.sub.e is Ru.
[0039] Within metallocene structure I, well-suited metallocene
materials may be chosen from within metallocene structure II:
##STR00003##
where R.sub.1, R.sub.2 and M.sub.e are as defined above.
[0040] Particularly well-suited metallocene materials from within
structure I may be chosen where R.sub.1, R.sub.2, Y.sub.1, Y.sub.2,
m and m' are as defined above, and M.sub.e is chosen from Ti, Cr,
Cu, Mn, Ag, Zr, Hf, Nb, V and Mo.
[0041] Desirably, the metallocene is selected from ferrocenes
(i.e., where M.sub.e is Fe), such as ferrocene, vinyl ferrocenes,
ferrocene derivatives, such as butyl ferrocenes or diarylphosphino
metal-complexed ferrocenes [e.g.,
1,1-bis(diphenylphosphino)ferrocene-palladium dichloride],
titanocenes (i.e., where M.sub.e is Ti), such as
bis(.eta..sup.5-2,4-cyclopentadien-1-yl)-bis-[2,6-difluoro-3-(1H-pyrrol-1-
-yl)phenyl] titanium which is available commercially from Ciba
Specialty Chemicals, Tarrytown, N.Y. under the tradename "IRGACURE"
784DC, and derivatives and combinations thereof. A particularly
desirable metallocene is ferrocene.
[0042] And bis-alkylmetallocenes, for instance, bis-alkylferrocenes
(such as diferrocenyl ethane, propanes, butanes and the like) are
also desirable for use herein, particularly since about half of the
equivalent weight of the material (as compared to a
non-bis-metallocene) may be employed to obtain the sought-after
results, all else being unchanged. Of the these materials,
diferrocenyl ethane is particularly desirable.
[0043] Of course, other materials may be well-suited for use as the
metallocene component. For instance,
M.sub.e[CW.sub.3--CO--CH.dbd.C(O.sup.-)--CW'.sub.3].sub.2, where
M.sub.e is as defined above, and W and W' may be the same or
different and may be selected from H, and halogens, such as F and
Cl. Examples of such materials include platinum (II) acetyl
acetonate ("PtACAC"), cobalt (II) acetyl acetonate ("CoACAC"),
nickel (II) acetyl acetonate ("NiACAC") and copper (II) acetyl
acetonate ("CuACAC"). Combinations of those materials may also be
employed.
[0044] A number of photoinitiators may be employed herein to
provide the benefits and advantages of the present invention to
which reference is made above. Photoinitiators enhance the rapidity
of the curing process when the photocurable compositions as a whole
are exposed to electromagnetic radiation. Certain metallocenes,
such as "IRGACURE" 784DC, may serve a dual purpose as both
metallocene and photoinitiator.
[0045] Examples of suitable photointiators for use herein include,
but are not limited to, photoinitiators available commercially from
Ciba Specialty Chemicals, Tarrytown, N.Y. under the "IRGACURE" and
"DAROCUR" tradenames, specifically "IRGACURE" 184
(1-hydroxycyclohexyl phenyl ketone), 907
(2-methyl-1-[4-(methylthio)phenyl]-2-morpholino propan-1-one), 369
(2-benzyl-2-N,N-dimethylamino-1-(4-morpholinophenyl)-1-butanone),
500 (the combination of 1-hydroxy cyclohexyl phenyl ketone and
benzophenone), 651 (2,2-dimethoxy-2-phenyl acetophenone), 1700 (the
combination of bis(2,6-dimethoxybenzoyl-2,4-,4-trimethyl
pentyl)phosphine oxide and
2-hydroxy-2-methyl-1-phenyl-propan-1-one), and 819
[bis(2,4,6-trimethyl benzoyl)phenyl phosphine oxide] and "DAROCUR"
1173 (2-hydroxy-2-methyl-1-phenyl-1-propane) and 4265 (the
combination of 2,4,6-trimethylbenzoyldiphenyl-phosphine oxide and
2-hydroxy-2-methyl-1-phenyl-propan-1-one); and the visible light
[blue] photoinitiators, dl-camphorquinone and "IRGACURE" 784DC. Of
course, combinations of these materials may also be employed
herein.
[0046] Other photoinitiators useful herein include alkyl pyruvates,
such as methyl, ethyl, propyl, and butyl pyruvates, and aryl
pyruvates, such as phenyl, benzyl, and appropriately substituted
derivatives thereof.
[0047] Photoinitiators particularly well-suited for use herein
include ultraviolet photoinitiators, such as 2,2-dimethoxy-2-phenyl
acetophenone (e.g., "IRGACURE" 651), and
2-hydroxy-2-methyl-1-phenyl-1-propane (e.g., "DAROCUR" 1173),
bis(2,4,6-trimethyl benzoyl)phenyl phosphine oxide (e.g.,
"IRGACURE" 819), and the ultraviolet/visible photoinitiator
combination of
bis(2,6-dimethoxybenzoyl-2,4,4-trimethylpentyl)phosphine oxide and
2-hydroxy-2-methyl-1-phenyl-propan-1-one (e.g., "IRGACURE" 1700),
as well as the visible photoinitiator
bis(.eta..sup.5-2,4-cyclopentadien-1-yl)-bis[2,6-difluoro-3-(1H-pyrrol-1--
yl)phenyl]titanium (e.g., "IRGACURE" 784DC).
[0048] Accelerators may also be included in the inventive rubber
toughened cyanoacrylate compositions, such as any one or more
selected from calixarenes and oxacalixarenes, silacrowns, crown
ethers, cyclodextrins, poly(ethyleneglycol)di(meth)acrylates,
ethoxylated hydric compounds and combinations thereof.
[0049] Of the calixarenes and oxacalixarenes, many are known, and
are reported in the patent literature. See e.g. U.S. Pat. Nos.
4,556,700, 4,622,414, 4,636,539, 4,695,615, 4,718,966, and
4,855,461, the disclosures of each of which are hereby expressly
incorporated herein by reference.
[0050] For instance, as regards calixarenes, those within the
following structure are useful herein:
##STR00004##
where R.sup.1 is alkyl, alkoxy, substituted alkyl or substituted
alkoxy; R.sup.2 is H or alkyl; and n is 4, 6 or 8.
[0051] One particularly desirable calixarene is tetrabutyl
tetra[2-ethoxy-2-oxoethoxy]calix-4-arene.
[0052] A host of crown ethers are known. For instance, examples
which may be used herein either individually or in combination, or
in combination with other first accelerator
##STR00005##
include 15-crown-5, 18-crown-6, dibenzo-18-crown-6,
benzo-15-crown-5-dibenzo-24-crown-8, dibenzo-30-crown-10,
tribenzo-18-crown-6, asym-dibenzo-22-crown-6, dibenzo-14-crown-4,
dicyclohexyl-18-crown-6, dicyclohexyl-24-crown-8,
cyclohexyl-12-crown-4, 1,2-decalyl-15-crown-5,
1,2-naphtho-15-crown-5, 3,4,5-naphtyl-16-crown-5,
1,2-methyl-benzo-18-crown-6, 1,2-methylbenzo-5,
6-methylbenzo-18-crown-6, 1,2-t-butyl-18-crown-6,
1,2-vinylbenzo-15-crown-5, 1,2-vinylbenzo-18-crown-6,
1,2-t-butyl-cyclohexyl-18-crown-6, asym-dibenzo-22-crown-6 and
1,2-benzo-1,4-benzo-5-oxygen-20-crown-7. See U.S. Pat. No.
4,837,260 (Sato), the disclosure of which is hereby expressly
incorporated here by reference.
[0053] Of the silacrowns, again many are known, and are reported in
the literature. For instance, a typical silacrown may be
represented within the following structure:
where R.sup.3 and R.sup.4 are organo groups which do not themselves
cause polymerization of the cyanoacrylate monomer, R.sup.5 is H or
CH.sub.3 and n is an integer of between 1 and 4. Examples of
suitable R.sup.3 and R.sup.4 groups are R groups, alkoxy groups,
such as methoxy, and aryloxy groups, such as phenoxy. The R.sup.3
and R.sup.4 groups may contain halogen or other substituents, an
example being trifluoropropyl. However, groups not suitable as
R.sup.4 and R.sup.5 groups are basic groups, such as amino,
substituted amino and alkylamino.
[0054] Specific examples of silacrown compounds useful in the
inventive compositions include:
##STR00006##
See e.g. U.S. Pat. No. 4,906,317 (Liu), the disclosure of which is
hereby expressly incorporated herein by reference.
[0055] Many cyclodextrins may be used in connection with the
present invention. For instance, those described and claimed in
U.S. Pat. No. 5,312,864 (Wenz), the disclosure of which is hereby
expressly incorporated herein by reference, as hydroxyl group
derivatives of an .alpha., .beta. or .gamma.-cyclodextrin which is
at least partly soluble in the cyanoacrylate would be appropriate
choices for use herein as the first accelerator component.
[0056] For instance, poly(ethylene glycol)di(meth)acrylates
suitable for use herein include those within the following
structure:
##STR00007##
where n is greater than 3, such as within the range of 3 to 12,
with n being 9 as particularly desirable. More specific examples
include PEG 200 DMA, (where n is about 4) PEG 400 DMA (where n is
about 9), PEG 600 DMA (where n is about 14), and PEG 800 DMA (where
n is about 19), where the number (e.g., 400) represents the average
molecular weight of the glycol portion of the molecule, excluding
the two methacrylate groups, expressed as grams/mole (i.e., 400
g/mol). A particularly desirable PEG DMA is PEG 400 DMA.
[0057] And of the ethoxylated hydric compounds (or ethoxylated
fatty alcohols that may be employed), appropriate ones may be
chosen from those within the following structure:
##STR00008##
where C.sub.m can be a linear or branched alkyl or alkenyl chain, m
is an integer between 1 to 30, such as from 5 to 20, n is an
integer between 2 to 30, such as from 5 to 15, and R may be H or
alkyl, such as C.sub.1-6 alkyl.
[0058] Commercially available examples of materials within the
above structure include those offered under the DEHYDOL tradename
from Henkel KGaA, Dusseldorf, Germany, such as DEHYDOL 100.
[0059] When used, the accelerator embraced by the above structures
should be included in the compositions in an amount within the
range of from about 0.01% to about 10% by weight, with the range of
about 0.1 to about 0.5% by weight being desirable, and about 0.4%
by weight of the total composition being particularly
desirable.
[0060] A stabilizer package is also ordinarily found in
cyanoacrylate compositions. The stabilizer package may include one
or more free radical stabilizers and anionic stabilizers, each of
the identity and amount of which are well known to those of
ordinary skill in the art. See e.g. U.S. Pat. Nos. 5,530,037 and
6,607,632, the disclosures of each of which are hereby incorporated
herein by reference.
[0061] Other additives may be included in the inventive rubber
toughened cyanoacrylate compositions to confer additional physical
properties, such as improved shock resistance, thickness (for
instance, polymethyl methacrylate), thixotropy (for instance fumed
silica), color, and enhanced resistance to thermal degradation [for
instance, maleimide compounds such as N,N'-meta-phenylene
bismaleimide (see U.S. Pat. No. 3,988,299 (Malofsky)), certain
mono, poly or hetero aromatic compounds characterized by at least
three substitutions on an aromatic ring thereof, two or more of
which being electron withdrawing groups (U.S. Pat. No. 5,288,794
(Attarwala)), certain quinoid compounds (U.S. Pat. No. 5,306,752
(Attarwala)), certain sulfur-containing compounds, such as an
anhydrosulfite, a sulfoxide, a sulfite, a sulfonate, a
methanesulfonate or a p-toluenesulfonate (U.S. Pat. No. 5,328,944
(Attarwala)), or certain sulfur-containing compounds, such as a
sulfinate, a cyclic sultinate naphthosultone compound substituted
with at least one strong electron withdrawing group at least as
strongly electron withdrawing as nitro (U.S. Pat. No. 5,424,343
(Attarwala)), and alkylating agents such as polyvinyl benzyl
chloride, 4-nitrobenzyl chloride, and combinations thereof,
silylating agents, and combinations thereof (U.S. Pat. No.
6,093,780 (Attarwala)), the disclosures of each of which are hereby
incorporated herein by reference]. Such additives therefore may be
selected from certain acidic materials (like citric acid),
thixotropy or gelling agents, thickeners, dyes, thermal degradation
resistance enhancers, and combinations thereof. See e.g. U.S.
patent application Ser. No. 11/119,703 and U.S. Pat. Nos.
5,306,752, 5,424,344 and 6,835,789, the disclosures of each of
which are hereby incorporated herein by reference.
[0062] These other additives may be used in the inventive
compositions individually in an amount from about 0.05% to about
20%, such as about 1% to 15%, desirably 5% to 10% by weight,
depending of course on the identity of the additive. For instance,
and more specifically, citric acid may be used in the inventive
compositions in an amount of 5 to 500 ppm, desirably 10 to 100
ppm.
[0063] A particularly desirable additive package for use in the
invention toughened cyanoacrylate compositions includes the
combination of two or more of citric acid, phthalic anhydride and
crown ether, desirably all three. See below Example 6, Tables 12
and 13.
[0064] As a general guide, for radiation curable cyanoacrylate
compositions including the rubber toughening components having (a)
reaction products of the combination of ethylene, methyl acrylate
and monomers having carboxylic acid cure sites, (b) dipolymers of
ethylene and methyl acrylate, and combinations of (a) and (b),
which once the reaction products and/or dipolymers are formed are
then substantially free of processing aids, such as octadecyl
amine, complex organic phosphate esters, stearic acid and/or
polyethylene glycol ether wax and anti-oxidants, such as
substituted diphenyl amine, it is desirable to include a
metallocene, such as ferrocene, in an amount within the range of
about 0.005% to about 4% or greater (desirably within the range of
about 0.01% to about 1.5%) by weight of the total composition and a
photoinitiator, such as "IRGACURE" 1700 or 819, or "DAROCUR" 1173,
in an amount within the range of about 0.125% to about 10% by
weight of the composition, with about 2% to about 4% or greater by
weight of the total composition being desirable. The rubber
toughening component should be used in amount within the range of
about 3% to about 20% by weight of the composition, with about 5%
to about 15% by weight of the total composition being desirable.
The balance of the composition is composed predominantly of a
cyanoacrylate component, such as ethyl-2-cyanoacrylate. Of course,
the amount of all the components together in the composition totals
100%.
[0065] In another aspect of the invention, there is provided a
method of bonding together two substrates, which method includes
applying to at least one of the substrates a composition as
described above, and thereafter mating together the substrates for
a time sufficient to permit the adhesive to fixture. For many
applications, the substrate should become fixed by the inventive
compositions in less than about 150 seconds, and depending on the
substrate as little as about 30 seconds. In addition, the inventive
composition should develop shear strength on the substrates between
which they have been applied, as well as side impact strength and
fracture toughness.
[0066] In that aspect of the invention relating to radiation
curable toughened cyanoacrylate compositions, a source of radiation
emitting electromagnetic waves is used to effect cure and may be
selected from ultraviolet light, visible light, electron beam,
x-rays, infrared radiation and combinations thereof. Desirably,
ultraviolet light is the radiation of choice, with appropriate
sources including "H", "D", "V", "X", "M" and "A" lamps, mercury
arc lamps, and xenon arc lamps (such as those commercially
available from Henkel Corporation, Rocky Hill, Conn., Fusion UV
Curing Systems, Buffalo Grove, Ill. or Spectroline, Westbury,
N.Y.); microwave-generated ultraviolet radiation; solar power and
fluorescent light sources. Any of these electromagnetic radiation
sources may use in conjunction therewith reflectors and/or filters,
so as to focus the emitted radiation onto a specific portion of a
substrate onto which has been dispensed a photocurable composition
and/or within a particular region of the electromagnetic spectrum.
Similarly, the electromagnetic radiation may be generated directly
in a steady fashion or in an intermittent fashion so as to minimize
the degree of heat build-up. Although the electromagnetic radiation
employed to cure the photocurable compositions into desired
reaction products is often referred to herein as being in the
ultraviolet region, that is not to say that other radiation within
the electromagnetic spectrum may not also be suitable. For
instance, in certain situations, radiation in the visible region of
the electromagnetic spectrum may also be advantageously employed,
whether alone or in combination with, for instance, radiation in
the ultraviolet region. Of course, microwave and infrared radiation
may also be advantageously employed under appropriate
conditions.
[0067] Higher or lower radiation intensities, greater or fewer
exposures thereto and length of exposure and/or greater or lesser
distances of the source of radiation to the composition may be
required to complete curing, depending of course on the particular
components of a chosen composition.
[0068] More specifically with respect to radiation intensity, the
chosen lamp should have a power rating of at least about 100 watts
per inch (about 40 watts per cm), with a power rating of at least
about 300 watts per inch (about 120 watts per cm) being
particularly desirable. Also, since the inclusion of a
photoinitiator in the composition may shift the wavelength within
the electromagnetic radiation spectrum at which cure occurs, it may
be desirable to use a source of electromagnetic radiation whose
variables (e.g., wavelength, distance, and the like) are readily
adjustable.
[0069] During the radiation curing process, the inventive
composition may be exposed to a source of electromagnetic radiation
that emits an amount of energy, measured in KJ/m.sup.2, determined
by parameters including: the size, type and geometry of the source;
the duration of the exposure to electromagnetic radiation; the
intensity of the radiation (and that portion of radiation emitted
within the region appropriate to effect curing); the absorbency of
electromagnetic radiation by any intervening materials, such as
substrates; and the distance the composition lies from the source
of radiation. Those persons of skill in the art should readily
appreciate that curing of the composition may be optimized by
choosing appropriate values for these parameters in view of the
particular components of the composition.
[0070] Commercially available curing systems, such as the "ZETA"
7200 or 7400 ultraviolet curing chamber (Henkel Corporation, Rocky
Hill, Conn.), Fusion UV Curing Systems F-300 B (Fusion UV Curing
Systems, Buffalo Grove, Ill.), Hanovia UV Curing System (Hanovia
Corp., Newark, N.J.), BlackLight Model B-100 (Spectroline,
Westbury, N.Y.) and RC500 A Pulsed UV Curing System (Xenon Corp.,
Woburn, Mass.), are well-suited for the purposes described herein.
Also, a Sunlighter UV chamber fitted with low intensity mercury
vapor lamps and a turntable may be employed herein.
[0071] In yet another aspect of the invention, there is provided
reaction products of the so-described compositions.
[0072] In still another aspect of the invention, there is provided
a method of preparing the so-described compositions. The method
includes providing a cyanoacrylate component, and combining
therewith with mixing a rubber toughening agent.
[0073] In a further aspect of the invention, there is provided a
method of conferring one or more of the following properties to
rubber toughened cyanoacrylate compositions improved fixture speed,
improved shear strength development over time, and improved
fracture toughness, which method includes the steps of providing a
cyanoacrylate composition, providing a rubber toughening agent of
(a) reaction products of the combination of ethylene, methyl
acrylate and monomers having carboxylic acid cure sites, (b)
diploymers of ethylene and methyl acrylate, and combinations
thereof, and being substantially free of processing acids and/or
anti-oxidants, and mixing together the cyanoacrylate compositions
and rubber toughening agents.
[0074] These aspects of the invention will be further illustrated
by the examples which follow.
EXAMPLES
Example 1
[0075] A number of samples were evaluated for their fixture speeds
on a variety of substrates and shelf lives under accelerated aging
conditions. The samples evaluated included LOCTITE BLACK MAX 380,
LOCTITE 4203, LOCTITE 4204, LOCTITE 4205, LOCTITE BLACK MAX 480,
and Sample Nos. 1-9, where the first five samples--labeled as
Sample A-E, respectively, are provided for comparative
purposes.
[0076] Sample Nos. 1-9 were prepared by mixing together the noted
constituents for a sufficient period of time to ensure substantial
homogeneity of the constituents. Ordinarily, about 30 minutes
should suffice, depending of course on the quantity of the
constituents used. The constituents and amounts of LOCTITE BLACK
MAX 380 (Sample A), LOCTITE 4203 (Sample B), LOCTITE 4204 (Sample
C), LOCTITE 4205 (Sample D), LOCTITE BLACK MAX 480 (Sample E), and
Sample Nos. 1, 2 and 3 are given in Tables 1a and 1b; Sample Nos.
4-6 are given in Table 1c; and Sample Nos. 7-9 are given in Table
1d.
TABLE-US-00001 TABLE 1a Component Sample Type Identity A B C D E CA
Ethyl-2-CA 60-100 60-100 60-100 60-100 60-100 Rubber VAMAC 10 -- --
-- 10 Tough- B-124 ening VAMAC G -- 8 8 8 -- Agent Accel-
Tetrabutyl -- 0.5 0.5 0.5 erator tetra(2-ethoxy- 2-oxoethoxy)
calix(4)arene Stabilizer MSA/SO.sub.2 0.012 0.005 0.005 0.005 --
BF.sub.3 -- -- -- -- 0.005 HQ 0.3 0.3 0.3 0.3 0.5 Filler Carbon
Black 1-5 -- -- -- 1-5 Silica -- 1 2 6 --
[0077] Samples B-D also contain phthalic anhydride, ethylene
sulfite and bismaleimide (at a level of 1-5 weight percent).
Samples A and E also contain phthalic anhydride.
TABLE-US-00002 TABLE 1b Component Sample No./Amt. (wt. %) Type
Identity 1 2 3 CA Ethyl-2-CA Balance Balance Balance Rubber VAMAC
VCS 5500 10 -- -- Toughening VAMAC G -- 10 -- Agent VAMAC B-124 --
-- 10 Stabilizer BF.sub.3 0.00075 0.00075 0.0045
TABLE-US-00003 TABLE 1c Component Sample No./Amt. (wt. %) Type
Identity 4 5 6 CA Ethyl-2-CA Balance Balance Balance Rubber VAMAC
VCS 5500 8 -- -- Toughening VAMAC B-124 -- -- 10 Agent Accelerator
Crown Ether 0.2 -- -- Tetrabutyl tetra (2- -- 0.5 --
ethoxy-2-oxoethoxy) calix (4)arene Stabilizer BF.sub.3 0.0005
0.0005 0.0045 Polymethylmethacrylate -- 8.0 -- Other Additives
Citric Acid 0.0005 -- -- Phthalic Anhydride -- -- 0.5
TABLE-US-00004 TABLE 1d Component Sample No./Amt. (wt. %) Type
Identity 7 8 9 CA Ethyl-2-CA Balance Balance Balance Rubber VAMAC
VCS 5500 8 8 8 Toughening Agent Accelerator Crown Ether 0.15 0.15
0.20 Stabilizer BF.sub.3 0.0005 0.0006 -- Filler Carbon Black --
0.1 -- Other Additives Citric Acid 0.0005 0.0005 0.0005 Phthalic
Anhydride -- -- 0.5
[0078] Each sample was applied to the substrates listed below in
Tables 2a-2d and fixture speeds, bond strengths in terms of peel
strength, shear (lap and/or block), side impact strength and
fracture toughness, respectively, were measured. For Samples A-E,
the data presented is based on published information from Henkel
Corporation in Technical Data Sheets.
[0079] By way of the background, the fixture speed is the time from
joining the two substrates (each of which being about 1 inch wide
and being aligned with about a 0.5 inch overlap) sufficient to hold
a 3 kg weight.
[0080] The lap shear strength was measured using
1''.times.4''.times.1/8'' metal or plastic substrates, with a 0.5
square inch overlap of the substrates, and the cyanoacrylate sample
between the substrate overlap. The cyanoacrylate sample was allowed
to cure at room temperature for the time interval as noted in
Tables 2b-2d. The resulting bond strength was measured using an
Instron instrument.
[0081] The side impact strength was measured using
1''.times.4''.times.1/8'' metal substrates, with a 1 square inch
overlap of the substrates, and the cyanoacrylate sample between the
substrate overlap. The cyanoacrylate sample was allowed to cure at
room temperature for the time interval as noted in Tables 2b-2d.
The assembly was then tested using a pendulum impact test fixture
to destructively determine the side impact strength.
[0082] The fracture toughness was measured according to ASTM 799 by
using tapered double cantilever beams ("DCBs") constructed from
metallic materials. Cyanoacrylate samples were applied between DCBs
with a 0 or 5 mil gap, and cured at room temperature for 8 days.
Fracture toughness was measured after that time.
TABLE-US-00005 TABLE 2a Sample Properties Substrate A B C D E
Fixture Times Aluminum 10-30 5-10 5-10 5-10 10-30 (secs)
Polycarbonate 30-90 -- -- -- 30-90 ABS 20-50 5-10 5-10 5-10 20-50
PVC 50-100 -- -- -- 50-100 Stainless Steel 60-120 10-20 20-30 10-20
60-120
[0083] As noted the data reported in Table 2a is available from
Technical Data Sheets published by Henkel Corporation. These data
were collected on substrates available at the time of evaluation,
which may no longer be in use today because of changes in substrate
materials or the processes by which the substrates are manufactured
and/or prepared for sale. Thus, the data in the Technical Data
Sheets generally is provided simply as a guide to the end user.
TABLE-US-00006 TABLE 2b Sample No. Physical Property 1 2 3
Stability @82.degree. C. Days 27 28 9 Visc. @25.degree. C. CPs 220
237 200 Fixture Time (sec) Steel 140 >300 >300 Al 30 45 50-60
Pine 30 60 >300 Side Impact (RTC) (Joules) Steel 24 hr 10.0 3.5
8.0 Al 24 hr 8.0 1.0 6.0 Fracture Toughness (J/cm.sup.2) 0 mil 816
730 850 5 mil 1823 1350 0
TABLE-US-00007 TABLE 2C Physical Properties Time Sample No. (each
in psi) (Hours) 4 5 6 7 Steel Lap Shear Strength 1 251 131 34.7 269
2 787 715 407 1073 4 1795 1207 1541 1699 6 1867 1225 1493 1798 24
2171 1769 2116 2112 72 2283 1975 2345 -- Aluminum Lap Shear
Strength 0.5 524 359 61 425 1 932 373 477 842 2 1217 441.1 964 1085
4 1533 498 1337 1430 24 2062 444 1450 1918 72 1911 715 2008 -- PVC
Block Shear Strength 0.5 138 475 0 90 1 523 755 15 377 2 443 765 81
389 4 535 784 128 556 24 788 804 339 786 G-10* Lap Shear Strength
0.5 977 1001 31 -- 1 1617 1218 13 -- 2 2049 1945 41 -- 4 2088 2245
336 -- 24 2364 2427 923 -- 72 2619 2434 1310 -- *G-10 = Epoxy
electronic circuit board (composite)
[0084] Reference may be made to FIGS. 1-3 for a graphic
representation of the lap shear strength on aluminum (FIG. 1) and
on steel (FIG. 2), and block shear strength on PVC (FIG. 3).
TABLE-US-00008 TABLE 2d Sample No. Physical Properties 7 8 9
Stability @82.degree. C. Time (Days) 18 14 14 Visc. @25.degree. C.
CPs 114 115 130 Lap Shear (psi) Al-PVC 24 hr RTC 795* 799* 791*
A1-Al 24 hr RTC 2112 2189 2307 Fixture Time (sec) Steel 40 55 35 Al
4 5 5 Pine 93 105 95 G-10 132 165 115 Lap Shear (psi) 48 hr RTC
2789 2648 2897 Steel [Grit Blasted] 24 hr RTC, 3305 3264 3697 24 hr
@ 120.degree. C., Rtpull 24 hr RTC, 2808 3029 3551 48 hr @
120.degree. C., Rtpull 180.degree. Peel (lbf/in) 48 hr RTC 19.0
24.4 26.0 *PVC substrate failure
Example 2
[0085] In this example, three VAMAC-brand rubbers, VMX 1012, VCS
5500 and VCS 5520, were dissolved in ethyl cyanoacrylate monomer to
formulate cyanoacrylate compositions. The difference in
constituents between these two VAMAC-brand rubbers from other
commercially available ones (i.e., VAMAC G and VAMAC B-124) is
shown below in Table 3. Like VAMAC VCS 5500, VMX 1012 and VCS 5520
are substantially free of processing aids such as the release
agents octadecyl amine, complex organic phosphate esters and/or
stearic acid, and anti-oxidants, such as substituted diphenyl
amine. Unlike VAMAC 5500, VMX 1012 is free of acid cure sites, and
VCS 5520 is believed to contain about half the amount of total acid
cure sites found in VAMAC G and B-124.
TABLE-US-00009 TABLE 3 Ingredients used to make VMX VCS VCS VAMAC
VAMAC VAMAC rubber 1012 5520 5500 G B-124 Ethylene x x X x x Methyl
acrylate x x X x x Monomers having -- x, 2 wt. % x, 4 wt. % x, 4
wt. % x, 4 wt. % carboxylic acid cure sites Internal release -- --
-- x x aid (Carbowax/ Nargard/ Polygaurd) Carbon black -- -- -- --
x, 2 wt. %
[0086] For comparative purpose, the VAMAC-brand rubbers identified
in Table 3 were each mixed with ethyl cyanoacrylate monomer in the
presence of BF.sub.3 as the stabilizer, as shown in Table 4 to form
Sample Nos. 10-11.
TABLE-US-00010 TABLE 4 Components Sample No. Type Identity 10 11
Cyanoacrylate Ethyl-2-CA Balance Balance Rubber Toughening VAMAC
VMX 1012 10 -- Agent VAMAC VCS 5520 -- 10 Stabilizer BF.sub.3
0.00075 0.00075
[0087] Referring below to Table 5, stability of the so formed
compositions was determined after accelerated ageing in aluminum
tubes at a temperature of 82.degree. C. By using VMX 1012 and VCS
5520, the cyanoacrylate compositions prepared therewith were
determined to be shelf stable for 15 and 20 days, respectively.
Sample Nos. 1 and 2 (see Tables 1a and 1b) containing VAMAC VCS
5500 and G, respectively, showed stability of 27 and 28 days,
respectively. In addition, a faster fixture time was observed for
Sample Nos. 10 and 11 (prepared with VAMAC VMX 1012 and VCS 5520,
respectively) on substrates, like aluminum, as compared to Sample
Nos. 1 and 2 (prepared with VAMAC G and B-124, respectively).
TABLE-US-00011 TABLE 5 Sample No. Properties 10 11 Stability
@82.degree. C. (days) 15 20 Visc. @25.degree. C. (cPs) 171 183
Fixture time (secs) -- Aluminum 10 10 Fixture time (secs) - Mild
Steel 180 160
Example 3
[0088] In this example, two VAMAC-brand rubbers, VMX 1012 and VCS
5520, were dissolved in ethyl cyanoacrylate monomer to formulate
cyanoacrylate compositions for a comparison to LOCTITE PRISM 480
(Sample E) as a control. Table 6 below shows the formulation
constituents of each sample.
TABLE-US-00012 TABLE 6 Component Sample No. Type Identity 12 13 14
Cyanoacrylate Ethyl-2-CA Balance Balance Balance Rubber Toughening
VAMAC VMX 1012 8 -- -- Agent VAMAC VCS 5520 -- 8 8 Stabilizer
BF.sub.3 0.001 0.0002 0.0001 Accelerator Crown ether 0.2 -- 0.2
Other additives Citric acid 0.005 0.005 0.005 Phthalic anhydride
0.5 0.5 0.5
[0089] Referring below to Table 7, stability of the so formed
cyanoacrylate compositions was again determined after accelerated
ageing in aluminum tubes at a temperature of 82.degree. C. By using
VAMAC VMX 1012 and VCS 5520, the cyanoacrylate compositions were
determined to be shelf stable for at least 10 days under the test
conditions, which is an improvement over the control. In addition,
a faster fixture time was observed for Sample Nos. 12 and 14
(prepared with VAMAC VMX 1012 and VCS 5520, respectively) on
substrates, like mild steel, aluminum, G-10 and pine, as compared
to the control. And after a 72 hour cure, the block shear strength
of each of Sample Nos. 12-14 was greater than that of the control
on substrates, like PVC, G-10 and phenolic.
TABLE-US-00013 TABLE 7 Sample No. Properties 12 13 14 E Stability
@82.degree. C. (days) 10 18 16 9 Fixture time (sec) Mild Steel 60
-- 60 100-110 Aluminum 5 -- 5 25 G-10 45 -- 90 >300 Pine 84 --
90 >300 Block strength (psi), 24 hour cure PVC 689 398 508 182
G-10 1810 2026 1366 1620 Phenolic 588 368 571 170 Polycarbonate 541
488 488 139 Block strength (psi), 72 hour cure PVC 663 768 727 353
G-10 2315 2275 2282 2168 Phenolic 854 719 718 517
Example 4
[0090] In this example, two VAMAC-brand rubbers, VAMAC VMX 1012 and
VCS 5520, were dissolved in ethyl cyanoacrylate monomer to
formulate cyanoacrylate compositions for a comparison to LOCTITE
PRISM 480 and LOCTITE FLASHCURE 4305, as controls. Table 8 below
shows the formulation constituents of each sample.
[0091] Photoinitiators--IRGACURE 819 and DAROCUR 1173 from Ciba
Specialty Chemicals, as well as LUCIRIN TPO-L from BASF--and a
metallalocene component--ferrocene (at a level of 100 ppm)--were
used in the compositions in this example, and BF.sub.3 was used as
a stabilizer. The VAMAC rubbers along with other ingredients (see
below Table 8) were mixed with ethyl cyanoacrylate for about 30
minutes to form a substantial homogeneous composition.
TABLE-US-00014 TABLE 8 Component Sample No./Amt. (Wt. %) Type
Identity 15 16 17 18 19 Monomer Ethyl-2-CA Balance Balance Balance
Bal- Bal- ance ance Rubber VAMAC 9.8 9.8 -- -- -- Toughening VCS
5500 Agent VAMAC -- -- 5 8 9.8 VMX 1012 Stabilizer BF.sub.3 0.003
0.003 0.003 0.003 0.004 Photo- IRGACURE -- -- 0.5 0.5 0.5 initiator
819 LUCIRIN 0.5 -- -- -- -- TPO-L DAROCUR -- 2 -- -- -- 1173
Metallocene Ferrocene 0.01 0.01 0.01 0.01 0.01
[0092] Referring below to Table 9, good shelf-life stability was
obtained with Sample Nos. 15-19 made with the VAMAC rubbers VAMAC
VCS 5500 and VAMAC VMX 1012. These samples show shelf-life
stability, when measured by accelerated ageing studies.
[0093] A drop of each sample was dispensed onto a glass slide, and
then exposed to UV light (30 mW/cm.sup.2 at 365 nm). A tack free
surface was observed to form within 5 and 3 seconds for Sample Nos.
17 and 18, respectively.
[0094] Lap shear strength on grit blasted steel for each sample
made from the VAMAC rubber VAMAC VCS 5500 and VAMAC VMX 1012 (which
were allowed to cure for 48 hours at room temperature) was
evaluated and found to be in the range of about 2,000-3,500 psi,
depending on the specified compositions. In addition, block
strength strength on polycarbonate substrates after a 10 second
UV-exposure is also presented in Table 9 for Sample Nos. 17 and 18.
The data in Table 9 illustrates that good bonding strength can be
obtained by using the formulations made with VAMAC rubbers.
TABLE-US-00015 TABLE 9 Sample Nos. Physical Properties 15 16 17 18
19 Stability @82.degree. C. (days) 9 8 8 7 9 Viscosity @25.degree.
C. (cP) -- -- 26 109 171 Tack free (secs) -- -- 5 3 -- Lap shear
(psi), steel grit blasted, 3474 3109 2259 2135 -- 48 hrs cure PC
block strength (Psi), 10 sec UV -- -- 1269 1798 -- cure @ 30
mw/cm.sup.2 of 365 nm, tested within 2 minutes PC block strength
(Psi), 10 sec UV -- -- -- 3675 -- cure @ 30 mw/cm.sup.2 of 365 nm,
tested after 24 hrs RT Cure
Example 5
[0095] In this example, fracture toughness was evaluated for a
radiation curable cyanoacrylate composition toughened in accordance
with the present invention.
[0096] Reference to Table 10 shows the identity and amounts of
constituents used in Sample No. 20.
TABLE-US-00016 TABLE 10 Sample No./ Component Amt. (Wt %) Type
Identity 20 Cyanoacrylate Ethyl-2-CA Balance Rubber Toughening
VAMAC VCS 5500 9.8 Agent Stabilizer BF.sub.3 0.003 Photoinitiator
IRGACURE 819 0.5 Metallocene Ferrocene 0.01
[0097] An evaluation of Sample No. 20 was performed in accordance
with ASTM D5045 (the substance of which is hereby incorporated
herein by reference) using three-point bend specimen geometry. The
mold used to prepare the sample for evaluation is constructed from
glass, with a Teflon film placed therewithin. The glass mold is
transmissive to UV radiation to permit curing of the sample by
exposure to such radiation. The Teflon permits the film formed
after exposure to be removed in a self supporting manner. Thus, the
mold with the sample within was exposed to UV radiation at an
intensity of 30 mW/cm.sup.2 at 365 nm for about 1-2 minutes for
each side. Table 11 below presents the G.sub.q (critical strain
energy release rate) and K.sub.q (plane-strain fracture toughness)
values obtained from that evaluation.
TABLE-US-00017 TABLE 11 Three-Point Sample No. Bend Results 20
G.sub.q J/cm.sup.2 2873.1 K.sub.q MPa m.sup.1/2 1.25
Example 6
[0098] In this example, Sample Nos. 21-27 were prepared with VAMAC
VCS 5500 as the rubber toughening component, together with various
additives, as shown below in Table 12.
TABLE-US-00018 TABLE 12 Component Sample No./Amt. (wt. %) Type
Identity 21 22 23 24 25 26 27 CA Ethyl-2-CA Balance Balance Balance
Balance Balance Balance Balance Rubber VAMAC 8 8 8 8 8 8 8
Toughening VCS 5500 Agent Stabilizer BF.sub.3 0.0005 0.0005 0.0005
0.0005 0.0005 0.0005 0.0005 Accelerator Crown Ether -- -- -- 0.2
0.2 0.2 0.20 Other Citric 0.0005 0.0008 -- 0.0005 0.0008 -- 0.0005
Additives Acid Phthalic -- -- 0.5 -- -- 0.5 0.5 Anhydride
[0099] Table 13 below shows the results of certain evaluations made
on Sample Nos. 21-27. For instance, side impact and lap shear data
are recorded in the table. The lap shear data for Sample No. 27 was
obtained from a sample with 2 ppm BF.sub.3, instead of 5 ppm as was
used for the side impact data.
TABLE-US-00019 TABLE 13 Sample No./Amt. (wt. %) Physical Properties
21 22 23 24 25 26 27 Side Impact, 24 hour 7.2 5.2 1.9 7.8 6.9 1.7
7.9 RTC 2 week 6.6 5.2 1.6 7.5 4.6 1.9 9.7 (Aluminum) 4 week 5.9
4.7 1.9 6.4 4.4 1.5 9.6 (Joules) 8 week 4.7 3.7 1.6 5.7 3.3 1.5 8.0
Lap shear, 24 hr 24 hour 4307 3687 -- 3113 3260 -- 3805 RTC,
heating 2 week 2429 1681 -- 2511 2389 -- 2736 aging @121C 4 week
798 1375 1883 2006 -- 2559 and RT Pull 8 week 0 430 -- 310 810 --
2003 [Steel, grit blasted] (psi)
* * * * *