U.S. patent application number 13/784875 was filed with the patent office on 2013-07-11 for thermoset dampener material.
This patent application is currently assigned to DOW GLOBAL TECHNOLOGIES LLC. The applicant listed for this patent is DOW GLOBAL TECHNOLOGIES LLC. Invention is credited to Martine M. Rousse, Ludovic Valette.
Application Number | 20130178558 13/784875 |
Document ID | / |
Family ID | 39734971 |
Filed Date | 2013-07-11 |
United States Patent
Application |
20130178558 |
Kind Code |
A1 |
Rousse; Martine M. ; et
al. |
July 11, 2013 |
THERMOSET DAMPENER MATERIAL
Abstract
Thermoset compositions useful for dampening vibrations at
elevated temperatures are disclosed. The thermoset compositions may
have a glass transition temperature of 150.degree. C. or greater, a
tan .delta. peak of 0.2 or greater, and a tan .delta. peak width
measured at half-height larger than about 40.degree. C., as
measured by dynamic thermo-mechanical analysis (DMTA) at a
frequency of 1 Hz. The thermoset compositions may be used to dampen
vibrations at temperatures in excess of 100.degree. C.
Inventors: |
Rousse; Martine M.;
(Drusenheim, FR) ; Valette; Ludovic; (Lake
Jackson, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
DOW GLOBAL TECHNOLOGIES LLC; |
Midland |
MI |
US |
|
|
Assignee: |
DOW GLOBAL TECHNOLOGIES LLC
Midland
MI
|
Family ID: |
39734971 |
Appl. No.: |
13/784875 |
Filed: |
March 5, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12668825 |
Jan 12, 2010 |
8404310 |
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PCT/US2008/071302 |
Jul 28, 2008 |
|
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13784875 |
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60962995 |
Aug 2, 2007 |
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Current U.S.
Class: |
523/400 ;
524/500; 524/508; 524/537; 524/538; 524/542; 524/611 |
Current CPC
Class: |
C09D 179/08 20130101;
C08L 63/00 20130101; C09D 161/02 20130101; C09D 169/00 20130101;
C08G 2261/3444 20130101; C09D 165/00 20130101; C09D 125/06
20130101; C09D 171/08 20130101; C09D 181/04 20130101; C09D 181/06
20130101; C08G 59/5086 20130101; C09D 159/00 20130101; C08G 59/4042
20130101; C08L 65/00 20130101; C09D 163/00 20130101 |
Class at
Publication: |
523/400 ;
524/611; 524/508; 524/538; 524/537; 524/542; 524/500 |
International
Class: |
C09D 163/00 20060101
C09D163/00; C09D 125/06 20060101 C09D125/06; C09D 179/08 20060101
C09D179/08; C09D 181/06 20060101 C09D181/06; C09D 159/00 20060101
C09D159/00; C09D 181/04 20060101 C09D181/04; C09D 161/02 20060101
C09D161/02; C09D 171/08 20060101 C09D171/08; C09D 165/00 20060101
C09D165/00; C09D 169/00 20060101 C09D169/00 |
Claims
1. A composite having improved dampening properties at elevated
temperatures, comprising: a thermoset composition disposed on a
substrate to form the composite; the thermoset composition having:
a glass transition temperature of 150.degree. C. or greater, a tan
.delta. peak of 0.2 or greater, and a tan .delta. peak width
measured at half-height larger than about 40.degree. C., as
measured by dynamic thermo-mechanical analysis (DMTA) at a
frequency of 1 Hz; wherein the composite is exposed to vibrations
at temperatures of 100.degree. C. or greater.
2. The composite of claim 1, wherein the thermoset composition
comprises: a crosslinked composition comprising the reaction
product of a curable composition comprising at least one
thermosetting resins and at least one hardener; wherein the
thermosetting resin comprising at least one of an epoxy, a phenolic
resin, a vinylic resin, a cycloaliphatic epoxy resin, and a cyanate
ester-based resin.
3. The composite of claim 2, wherein the thermoset composition
further comprises a high temperature resistant thermoplastic
resin.
4. The composite of claim 3, wherein the high temperature resistant
thermoplastic resin is selected from the group consisting of a
polyetherimides, a polyphenylene ether, a polyoxyphenylene, a
polysulphone, a syndiotactic polystyrene, a polyaryl ether ketone,
a polycarbonate, an acetal, a polyimide, and a polyarylene
sulfide.
5. The composite of claim 1, wherein the thermoset composition
further comprises at least one of a catalyst, an inorganic filler,
a solvent, a toughening agent, and a fibrous reinforcement.
6. A thermoset composition having improved dampening properties at
elevated temperatures, comprising: a reaction product of a curable
composition comprising at least one thermosetting resin and at
least one hardener; wherein the thermoset composition has: a glass
transition temperature of 150.degree. C. or greater, a tan .delta.
peak of 0.2 or greater, and a tan .delta. peak width measured at
half-height larger than about 40.degree. C., as measured by dynamic
thermo-mechanical analysis (DMTA) at a frequency of 1 Hz.
7. The thermoset composition of claim 6, wherein the at least one
thermosetting resin is selected from the group consisting of an
epoxy, a phenolic resin, a vinylic resin, a cycloaliphatic epoxy
resin, and a cyanate ester-based resin.
8. The thermoset composition of claim 7, wherein the curable
composition further comprises a high temperature resistant
thermoplastic resin.
9. The thermoset composition of claim 8, wherein the high
temperature resistant thermoplastic resin is selected from the
group consisting of a polyetherimides, a polyphenylene ether, a
polyoxyphenylene, a polysulphone, a syndiotactic polystyrene, a
polyaryl ether ketone, a polycarbonate, an acetal, a polyimide, and
a polyarylene sulfide.
10. The thermoset composition of claim 6, wherein the curable
composition further comprises at least one of a catalyst, an
inorganic filler, a solvent, a toughening agent, and a fibrous
reinforcement.
Description
CROSS REFERENCE TO RELATED SUBJECT MATTER
[0001] This application is a Divisional application of U.S. patent
application Ser. No. 12/668,825, filed Jan. 12, 2010, which is a
National Stage Application under 35 U.S.C. of PCT/US2008/071302,
filed Jul. 28, 2008, and published as WO2009018194 on May 2, 2009,
which claims the benefit of U.S. Provisional Application Serial No.
60/962,995, filed Aug. 2, 2007, the entire contents of which are
incorporated herein by reference.
BACKGROUND OF DISCLOSURE
[0002] 1. Field of the Disclosure
[0003] Embodiments disclosed herein relate generally to
thermosetting systems for dampening vibrations. More specifically,
embodiments disclosed herein relate to thermosetting systems for
dampening vibrations at high temperatures.
[0004] 2. Background
[0005] Dampener materials commonly used in the transportation and
aerospace industry include rubber materials, bituminous pads, and
other similar materials. These materials are typically only
effective at dampening vibrations at low temperatures, most often
at room temperature.
[0006] However, parts used in the transportation and aerospace
industry are often subjected to mechanical vibrations at high
temperatures. In particular, vibration dampening at temperatures in
excess of 150.degree. C. is very difficult to achieve.
[0007] There exists a need for thermoset compositions useful for
vibration dampening at elevated temperatures. As illustrated by the
following references, there exists various materials having high
glass transition temperatures or that are stable at high
temperatures.
[0008] For example, high temperature thermoplastic compositions are
disclosed in "Creep behaviour of polymer blends based on epoxy
matrix and intractable high T.sub.g thermoplastic," C. Gauthier et
al., Polymer International (2004), 53(5), pages 541-549.
Compositions disclosed include a dispersion of crosslinked
thermoset epoxy-amine in a thermoplastic polyetherimide matrix.
Similarly, high temperature (>140.degree. C.) corrosion
protective coatings including high T.sub.g thermoplastic and
thermoset epoxyamine monomers are disclosed in "Innovative pipe
coating material and process for high temperature fields,"
Sauvant-Maynot et al., Oil & Gas Science and Technology (2002),
57(3), pages 269-279.
[0009] A material for microelectronics packaging having a low
dielectric constant and high thermal stability is disclosed in
"Polyquinoline/bismaleimide blends as low-dielectric constant
materials," Nalwa et al., Proceedings--Electrochemical society
(1999), 98-6 (Electrochemical Processing in ULSI Fabrication I and
Interconnect and Contact Metallization: Materials, Processes, and
Reliability), pages 135-144.
[0010] A hot-melt processable thermoset composition prepared by
blending
tetraglycidyl-4,4'-diaminodiphenylmethane/4,4'-diaminodiphenyl
sulfone epoxy resin and a high T.sub.g thermoplastic polyimide is
disclosed in "Polyimide-modified epoxy system:
time-temperature-transformation diagrams, mechanical and thermal
properties," Biolley et al, Polymer (1994), 35(3), pages 558-564.
The consequences of the thermoplastic incorporation, such as a
polyimide concentration of 10 weight percent, were a slight
increase in T.sub.g and limited improvements in stress at rupture
and strain-energy release rate Glc compared to the unmodified epoxy
matrix.
[0011] Thermoplastic/thermosetting polyimide blends containing
polyimide PI 2080 (I) [62181-46-8] and
N,N'-(methylenedi-p-phenylene)bismaleimide are disclosed in
"Preparation and characterization of thermoplastic/thermosetting
polyimide blends," Yamamoto et al, SAMPE Journal (1985), 21(4),
pages 6-10. The blends are heated at temperatures greater than
180.degree. C. to form a co-continuous composite
thermoplastic-thermoset structure having high glass transition
temperatures (greater than 300.degree. C.). Carbon fabric- and
glass fabric-reinforced blends maintained their mechanical
properties at temperatures less than 260.degree. C.
[0012] EP 1225203 discloses use of thermoplastic additives with
high glass transition temperatures (140.degree. C. to 220.degree.
C.) in thermosetting compositions. Modified polyoxyphenylenes
dissolved in styrene were used in glass fiber-reinforced
thermosetting compositions based on unsaturated maleic acid
resins.
[0013] U.S. Pat. Nos. 6,103,810 and 6,268,425 disclose alloys
formed from mixed alkali pyrophosphate glass and high temperature
organic thermoplastic or thermosetting polymers having working
temperatures which are compatible with that of the glass and/or the
precursor glass. The glass and polymers are combined at the working
temperature to form an intimate mixture of an essentially uniform,
fine grained microstructure.
[0014] EP 382575 discloses a co-continuous thermoplastic-thermoset
crosslinked blend, such as a siloxane-polyimide prepared by the
reaction of bis[4-(3-aminophenoxy)phenyl]sulfone,
9,9-bis(aminophenyl)fluorine, an amine-terminated
polydimethylsiloxane, and biphenyltetracarboxylic dianhydride
blended with resorcinol diglycidy ether, phenol novalac resin, and
4,4'-diaminodiphenyl sulfone, the mixture of which is cured at
130.degree. C. for 2 hours and at 180.degree. C. for two hours.
Fiber reinforced structures formed from the cured resins disclosed
have a glass transition temperature (T.sub.g) of at least
120.degree. C., among other properties.
[0015] JP 2005126473 discloses an ethylene copolymer rubber
composition having good dynamic fatigue at high temperatures. The
heat-resistant dampening rubber composition is obtained by
premixing of (b) 50-85 wt. % of a hydrogenated nitrile rubber
having .ltoreq.80 iodine value with (c) 50-15 wt. % of zinc
methacrylate [with the proviso that the sum total of the (b) and
(c) is 100 wt. %]. The resultant mixture in an amount of 2-200
parts by weight is then mixed with (a) 100 parts by weight of an
ethylene-.alpha.-olefinic copolymer rubber and 2-20 parts by weight
of an organic peroxide cross-linking agent so as to make (c) the
zinc methacrylate which is used as a reinforcing agent unevenly
distributed in (b) the hydrogenated nitrile rubber having
.ltoreq.80 iodine value.
[0016] JP 11071568 discloses adhesive compositions including (A)
0.1-20 wt. % of a non-liquid crystalline resin such as a nylon
resin, e.g. nylon 66, nylon 6 or a nylon copolymer containing the
nylon 66 or nylon 6 as a main component, (B) 80-99.9 wt. % of a
liquid-crystalline resin, and preferably (C) an inorganic filler
having a weight-average major axis or weight-average fiber length
of 100-400 .mu.m, a .ltoreq.60 .mu.m major axis or fiber length
filler content of 10-50 wt. % based on the total amount of all the
fillers, and an average thickness or average fiber diameter of 5-15
.mu.m in an amount of 5-300 parts per 100 parts by weight of the
total amount of the components A and B. The compositions are high
in strength, excellent in moldability, heat resistance, toughness,
oil resistance, gasoline resistance, abrasion resistance, molded
product surface smoothness, high temperature rigidity, dimensional
stability and vibration-dampening characteristics and high in
strength by including a non-liquid crystalline resin and a
liquid-crystalline resin in a specific ratio.
[0017] U.S. Pat. No. 6,822,067 discloses polycyanates and
polycyanate/epoxide combinations that are useful as laminating
resins. The resulting thermosetting polycyanate copolymers have a
high proportion of triazine structures and glass transition
temperatures up to about 200.degree. C.
[0018] Compositions or blends having high glass transition
temperature materials or materials that are stable at high
temperatures may be described in the references above. However,
there is a lack of vibration dampening materials that are effective
at elevated temperatures.
[0019] Accordingly, there exists a need for thermoset dampener
materials effective a dampening vibrations when used at elevated
temperatures.
SUMMARY OF THE DISCLOSURE
[0020] In one aspect, embodiments disclosed herein relate to a
process for dampening vibrations in an article. The process may
include: disposing a thermoset composition on a substrate to form a
composite; the thermoset composition having: a glass transition
temperature of 150.degree. C. or greater, a tan .delta. peak of 0.2
or greater, and a tan .delta. peak width measured at half-height
larger than about 40.degree. C., as measured by dynamic
thermo-mechanical analysis (DMTA) at a frequency of 1 Hz; exposing
the composite to vibrations at temperatures of 100.degree. C. or
greater.
[0021] In another aspect, embodiments disclosed herein relate to
composites having improved dampening properties at elevated
temperatures. The composites may include: a thermoset composition
disposed on a substrate; the thermoset composition having: a glass
transition temperature of 150.degree. C. or greater, a tan .delta.
peak of 0.2 or greater, and a tan .delta. peak width measured at
half-height larger than about 40.degree. C., as measured by dynamic
thermo-mechanical analysis (DMTA) at a frequency of 1 Hz; wherein
the composite is exposed to vibrations at temperatures of
100.degree. C. or greater.
[0022] In other aspects, embodiments disclosed herein relate to
thermoset compositions having improved dampening properties at
elevated temperatures. The thermoset compositions may include: a
reaction product of a curable composition comprising at least one
thermosetting resin and at least one hardener; wherein the
thermoset composition has: a glass transition temperature of
150.degree. C. or greater, a tan .delta. peak of 0.2 or greater,
and a tan .delta. peak width measured at half-height larger than
about 40.degree. C., as measured by dynamic thermo-mechanical
analysis (DMTA) at a frequency of 1 Hz.
[0023] Other aspects and advantages will be apparent from the
following description and the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1 presents Dynamic Mechanical Thermal Analysis results
for a resin prepared according to embodiments disclosed herein
DETAILED DESCRIPTION
[0025] In one aspect, embodiments disclosed herein relate to
thermosetting compositions for use as dampener materials at
elevated temperatures. In other aspects, embodiments disclosed
herein relate to dampener materials having a high glass transition
temperature and a high dampening factor. In more specific aspects,
embodiments disclosed herein relate to thermoset dampener materials
having a glass transition temperature of at least 150.degree. C.
and a high dampening factor defined by tan .delta. greater than 0.2
with a peak width at half-height of at least 40.degree. C. Such
dampener materials may be useful for transportation, aerospace,
castings, coatings, and electronics/electrical applications
requiring high service temperature dampening.
[0026] Embodiments of the dampener materials for reducing the
effect of vibrations at elevated temperatures may include
compositions based upon thermosetting resins capable of generating
a crosslinked network upon curing. Vibrations that may be
effectively reduced include vibrations between 0 and 10,000 Hz in
some embodiments; between 0 and 3000 Hz in other embodiments; and
between 0 and 500 Hz in yet other embodiments.
[0027] In various embodiments, thermosetting resins may include
epoxy resins, phenolic resins or resins capable of generating
phenolic moieties at high temperature, vinylic resins,
cycloaliphatic epoxy resins, nitrogen containing resins such as
cyanate ester based resins, as well as other thermosetting
compositions, or mixtures thereof. Dampener materials may also
include various additives, including other resins such as high
temperature resistant thermoplastics. Additionally, curable
compositions for forming the thermoset dampener materials may
include hardeners and catalysts.
[0028] For example, thermosetting dampener materials disclosed
herein may include at least one thermosetting resin, and optionally
at least one of a hardener, a catalyst, an inorganic filler, a
fibrous reinforcement, a high temperature resistant thermoplastic
resin, and a solvent. In various embodiments, following cure of the
thermosetting composition, the cured composition may have at least
one of a glass transition temperature of at least 150.degree. C., a
high dampening factor defined by tan .delta. greater than 0.2 with
a peak width at half-height of at least 40.degree. C., as measured
by dynamic thermo-mechanical analysis (DMTA) at a frequency of 1
Hz. The cured composition may be attached to an article to reduce
the interference vibration of the article at temperatures greater
than 100.degree. C.
[0029] The glass transition temperature of the cured composition
may be higher than about 150.degree. C. in some embodiments; higher
than about 170.degree. C. in other embodiments; higher than about
180.degree. C. in other embodiments; higher than about 200.degree.
C. in other embodiments; lower than about 300.degree. C. in other
embodiments; lower than about 280.degree. C. in other embodiments;
and lower than about 260.degree. C. in yet other embodiments, as
measured using DMTA at a frequency of 1 Hz.
[0030] The height of the tan .delta. peak of the cured composition
is higher than about 0.2 in some embodiments; higher than about
0.25 in other embodiments; higher than about 0.3 in other
embodiments; and higher than about 0.35 in yet other embodiments,
as measured using DMTA at a frequency of 1 Hz.
[0031] The width of the tan .delta. peak of the cured composition
is larger than about 40.degree. C. when measured at half-height for
sonic embodiments of the cured compositions disclosed herein;
larger than about 50.degree. C. in other embodiments; and larger
than about 60.degree. C. in yet other embodiments.
[0032] In other embodiments, a shoulder or a secondary tan .delta.
peak is shown by the cured composition when measured by DMTA. The
shoulder of the secondary tan .delta. peak may be at a lower or
higher temperature than the primary tan .delta. peak. In some
embodiments, the secondary tan .delta. peak is located at more than
about 10.degree. C. from the main tan .delta. peak; more than about
20.degree. C. from the main tan .delta. peak in other embodiments;
more than about 30.degree. C. from the main tan .delta. peak in
other embodiments; less than about 150.degree. C. from the main tan
.delta. peak in other embodiments; less than about 100.degree. C.
from the main tan .delta. peak in other embodiments; and less than
about 80.degree. C. from the main tan .delta. peak in yet other
embodiments.
[0033] Dampener materials disclosed herein may reduce the
vibrations observed at a temperature higher than about 100.degree.
C. in some embodiments; higher than about 120.degree. C. in other
embodiments; higher than about 150.degree. C. in other embodiments;
higher than about 180.degree. C. in other embodiments; and higher
than about 200.degree. C. in yet other embodiments.
[0034] The thermoset dampener materials disclosed herein may be
attached to an article or substrate by any suitable means. For
example, thermoset dampener materials disclosed herein may be
attached to an article by coating, spraying, dipping, casting,
potting, laminating, gluing, and sandwiching. In some embodiments,
the uncured composition is disposed on a substrate and cured in
place to produce a modified article with reduced vibration at high
temperatures.
[0035] As described above, thermoset dampener materials described
herein may include one or more thermosetting resins, such as epoxy
resins, phenolic resins, vinylic resins, cyanate ester resins, and
others. Dampener materials may also include various additives, such
as high temperature resistant thermoplastics, among other
additives. Each of these will be described in more detail
below.
[0036] Epoxy Resin
[0037] The epoxy resins used in embodiments disclosed herein may
vary and include conventional and commercially available epoxy
resins, which may be used alone or in combinations of two or more,
including, for example, novalac resins, isocyanate modified epoxy
resins, and carboxylate adducts, among others. In choosing epoxy
resins for compositions disclosed herein, consideration should not
only be given to properties of the final product, but also to
viscosity and other properties that may influence the processing of
the resin composition.
[0038] The epoxy resin component may be any type of epoxy resin
useful in molding compositions, including any material containing
one or more reactive oxirane groups, referred to herein as "epoxy
groups" or "epoxy functionality." Epoxy resins useful in
embodiments disclosed herein may include mono-functional epoxy
resins, multi- or poly-functional epoxy resins, and combinations
thereof. Monomeric and polymeric epoxy resins may be aliphatic,
cycloaliphatic, aromatic, or heterocyclic epoxy resins. The
polymeric epoxies include linear polymers having terminal epoxy
groups (a diglycidyl ether of a polyoxyalkylene glycol, for
example), polymer skeletal oxirane units (polybutadiene
polyepoxide, for example) and polymers having pendant epoxy groups
(such as a glycidyl methacrylate polymer or copolymer, for
example). The epoxies may be pure compounds, but are generally
mixtures or compounds containing one, two or more epoxy groups per
molecule. In some embodiments, epoxy resins may also include
reactive --OH groups, which may react at higher temperatures with
anhydrides, organic acids, amino resins, phenolic resins, or with
epoxy groups (when catalyzed) to result in additional
crosslinking.
[0039] In general, the epoxy resins may be glycidated resins,
cycloaliphatic resins, epoxidized oils, and so forth. The
glycidated resins are frequently the reaction product of a glycidyl
ether, such as epichlorohydrin, and a bisphenol compound such as
bisphenol A; C.sub.4 to C.sub.28 alkyl glycidyl ethers; C.sub.2 to
C.sub.28 alkyl-and alkenyl-glycidyl esters; C.sub.1 to C.sub.28
alkyl-, mono- and poly-phenol glycidyl ethers; polyglycidyl ethers
of polyvalent phenols, such as pyrocatechol, resorcinol,
hydroquinone, 4,4'-dihydroxydiphenyl methane (or bisphenol F),
4,4'-dihydroxy-3,3'-dimethyldiphenyl methane,
4,4'-dihydroxydiphenyl dimethyl methane (or bisphenol A),
4,4'-dihydroxydiphenyl methyl methane, 4,4'-dihydroxydiphenyl
cyclohexane, 4,4'-dihydroxy-3,3'-dimethyldiphenyl propane,
4,4'-dihydroxydiphenyl sulfone, and tris(4-hydroxyphynyl)methane;
polyglycidyl ethers of the chlorination and bromination products of
the above-mentioned diphenols; polyglycidyl ethers of novolacs;
polyglycidyl ethers of diphenols obtained by esterifying ethers of
diphenols obtained by esterifying salts of an aromatic
hydrocarboxylic acid with a dihaloalkane or dihalogen dialkyl
ether; polyglycidyl ethers of polyphenols obtained by condensing
phenols and long-chain halogen paraffins containing at least two
halogen atoms. Other examples of epoxy resins useful in embodiments
disclosed herein include bis-4,4'-(1-methylethylidene) phenol
diglycidyl ether and (chloromethyl) oxirane bisphenol A diglycidyl
ether.
[0040] In some embodiments, the epoxy resin may include glycidyl
ether type; glycidyl-ester type; alicyclic type; heterocyclic type,
and halogenated epoxy resins, etc. Non-limiting examples of
suitable epoxy resins may include cresol novolac epoxy resin,
phenolic novolac epoxy resin, biphenyl epoxy resin, hydroquinone
epoxy resin, stilbene epoxy resin, and mixtures and combinations
thereof.
[0041] Suitable polyepoxy compounds may include resorcinol
diglycidyl ether (1,3-bis-(2,3-epoxypropoxy)benzene), diglycidyl
ether of bisphenol A (2,2-bis(p-(2,3-epoxypropoxy)phenyl)propane),
triglycidyl p-aminophenol
(4-(2,3-epoxypropoxy)-N,N-bis(2,3-epoxypropyl)aniline), diglycidyl
ether of bromobispehnol A
(2,2-bis(4-(2,3-poxypropoxy)3-bromo-phenyl)propane),
diglydicylether of bisphenol F
(2,2-bis(p-(2,3-epoxypropoxy)phenyl)methane), triglycidyl ether of
meta- and/or para-aminophenol
(3-(2,3-epoxypropoxy)N,N-bis(2,3-epoxypropyl)aniline), and
tetraglycidyl methylene dianiline
(N,N,N,N',N'-tetra(2,3-epoxypropyl) 4,4'-diaminodiphenyl methane),
and mixtures of two or more polyepoxy compounds. A more exhaustive
list of useful epoxy resins found may be found in Lee, H. and
Neville, K., Handbook of Epoxy Resins, McGraw-Hill Book Company,
1982 reissue.
[0042] Other suitable epoxy resins include polyepoxy compounds
based on aromatic amines and epichlorohydrin, such as
N,N'-diglycidyl-aniline;
N,N'-dimethyl-N,N'-diglycidyl-4,4'-diaminodiphenyl methane;
N,N,N'N'-tetraglycidyl-4,4'-diaminodiphenyl methane;
N-diglycidyl-4-aminophenyl glycidyl ether; and
N,N,N',N'-tetraglycidyl-1,3-propylene bis-4-aminobenzoate. Epoxy
resins may also include glycidyl derivatives of one or more of:
aromatic diamines, aromatic monoprimary amines, aminophenols,
polyhydric phenols, polyhydric alcohols, polycarboxylic acids.
[0043] Useful epoxy resins include, for example, polyglycidyl
ethers of polyhydric polyols, such as ethylene glycol, triethylene
glycol, 1,2-propylene glycol, 1,5-pentanediol, 1,2,6-hexanetriol,
glycerol, and 2,2-bis(4-hydroxy cyclohexyl)propane; polyglycidyl
ethers of aliphatic and aromatic polycarboxylic acids, such as, for
example, oxalic acid, succinic acid, glutaric acid, terephthalic
acid, 2,6-napthalene dicarboxylic acid, and dimerized linoleic
acid; polyglycidyl ethers of polyphenols, such as, for example,
bis-phenol A, bis-phenol F, 1,1-bis(4-hydroxyphenyl)ethane,
1,1-bis(4-hydroxyphenyl)isobutane, and 1,5-dihydroxy napthalene;
modified epoxy resins with acrylate or urethane moieties;
glycidlyamine epoxy resins; and novolac resins.
[0044] The epoxy compounds may be cycloaliphatic or alicyclic
epoxides. Examples of cycloaliphatic epoxides include diepoxides of
cycloaliphatic esters of dicarboxylic acids such as
bis(3,4-epoxycyclohexylmethyl)oxalate,
bis(3,4-epoxycyclohexylmethyl)adipate,
bis(3,4-epoxy-6-methylcyclohexylmethyl)adipate,
bis(3,4-epoxycyclohexylmethyl)pimelate; vinylcyclohexene diepoxide;
limonene diepoxide; dicyclopentadiene diepoxide; and the like.
Other suitable diepoxides of cycloaliphatic esters of dicarboxylic
acids are described, for example, in U.S. Pat. No. 2,750,395.
[0045] Other cycloaliphatic epoxides include
3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylates such as
3,4 -epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate;
3,4-epoxy-1-methylcyclohexyl-methyl-3,4-epoxy-1-methylcyclohexane
carboxylate; 6-methyl-3,4-epoxycyclohexylmethylmethyl-6-methyl-3,4
epoxycyclohexane carboxylate;
3,4-epoxy-2-methylcyclohexylmethyl-3,4-epoxy-2-methylcyclohexane
carboxylate;
3,4-epoxy-3-methylcyclohexyl-methyl-3,4-epoxy-3-methyleyclohexane
carboxylate;
3,4-epoxy-5-methyleyelohexyl-methyl-3,4-epoxy-5-methylcyclohexane
carboxylate and the like. Other suitable
3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylates are
described, for example, in U.S. Pat. No. 2,890,194.
[0046] Further epoxy-containing materials which are particularly
useful include those based on glycidyl ether monomers. Examples are
di- or polyglycidyl ethers of polyhydric phenols obtained by
reacting a polyhydric phenol with an excess of chlorohydrin such as
epichlorohydrin. Such polyhydric phenols include resorcinol,
bis(4-hydroxyphenyl)methane (known as bisphenol F),
2,2-bis(4-hydroxyphenyl)propane (known as bisphenol A),
2,2-bis(4'-hydroxy-3',5'-dibromophenyl)propane,
1,1,2,2-tetrakis(4'-hydroxy-phenyl)ethane or condensates of phenols
with formaldehyde that are obtained under acid conditions such as
phenol novolacs and cresol novolacs. Examples of this type of epoxy
resin are described in U.S. Pat. No. 3,018,262. Other examples
include di- or polyglycidyl ethers of polyhydric alcohols such as
1,4-butanediol, or polyalkylene glycols such as polypropylene
glycol and di- or polyglycidyl ethers of cycloaliphatic polyols
such as 2,2-bis(4-hydroxycyclohexyl)propane. Other examples are
monofunctional resins such as cresyl glycidyl ether or butyl
glycidyl ether.
[0047] Another class of epoxy compounds are polyglycidyl esters and
poly(beta-methylglycidyl) esters of polyvalent carboxylic acids
such as phthalic acid, terephthalic acid, tetrahydrophthalic acid
or hexahydrophthalic acid. A further class of epoxy compounds are
N-glycidyl derivatives of amines, amides and heterocyclic nitrogen
bases such as N,N-diglycidyl aniline, N,N-diglycidyl toluidine,
N,N,N'N'-tetraglycidyl bis(4-aminophenyl)methane, triglycidyl
isocyanurate, N,N'-diglycidyl ethyl urea,
N,N'-diglycidyl-5,5-dimethylhydantoin, and
N,N'-diglycidyl-5-isopropylhydantoin.
[0048] Still other epoxy-containing materials are copolymers of
acrylic acid esters of glycidol such as glycidylacrylate and
glycidylmethacrylate with one or more copolymerizable vinyl
compounds. Examples of such copolymers are 1:1
styrene-glycidylmethacrylate, 1:1
methyl-methacrylateglycidylacrylate and a 62.5:24:13.5
methylmethacrylate-ethyl acrylate-glycidylmethacrylate.
[0049] Epoxy compounds that are readily available include
octadecylene oxide; glycidylmethacrylate; D.E.R. 331 (bisphenol A
liquid epoxy resin) and D.E.R. 332 (diglycidyl ether of bisphenol
A) available from The Dow Chemical Company, Midland, Mich.;
vinylcyclohexene dioxide;
3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate;
3,4-epoxy-6-methylcyclohexyl-methyl-3,4-epoxy-6-methylcyclohexane
carboxylate; bis(3,4-epoxy-6-methylcyclohexyl-methyl) adipate;
bis(2,3-epoxycyclopentyl) ether; aliphatic epoxy modified with
polypropylene glycol; dipentene dioxide; epoxidized polybutadiene;
silicone resin containing epoxy functionality; flame retardant
epoxy resins (such as a brominated bisphenol type epoxy resin
available under the tradename D.E.R. 580, available from The Dow
Chemical Company, Midland, Mich.); 1,4-butanediol diglycidyl ether
of phenolformaldehyde novolac (such as those available under the
tradenames D.E.N. 431 and D.E.N. 438 available from The Dow
Chemical Company, Midland, Mich.); and resorcinol diglycidyl ether
Although not specifically mentioned, other epoxy resins under the
tradename designations D.E.R. and D.E.N. available from the Dow
Chemical Company may also be used.
[0050] Epoxy resins may also include isocyanate modified epoxy
resins. Polyepoxide polymers or copolymers with isocyanate or
polyisocyanate functionality may include epoxy-polyurethane
copolymers. These materials may be formed by the use of a
polyepoxide prepolymer having one or more oxirane rings to give a
1,2-epoxy functionality and also having open oxirane rings, which
are useful as the hydroxyl groups for the dihydroxyl-containing
compounds for reaction with diisocyanate or polyisocyanates. The
isocyanate moiety opens the oxirane ring and the reaction continues
as an isocyanate reaction with a primary or secondary hydroxyl
group. There is sufficient epoxide functionality on the polyepoxide
resin to enable the production of an epoxy polyurethane copolymer
still having effective oxirane rings. Linear polymers may be
produced through reactions of diepoxides and diisocyanates. The di-
or polyisocyanates may be aromatic or aliphatic in some
embodiments.
[0051] Other suitable epoxy resins are disclosed in, for example,
U.S. Pat. Nos. 7,163,973, 6,632,893, 6,242,083, 7,037,958,
6,572,971, 6,153,719, and 5,405,688 and U.S. Patent Application
Publication Nos. 20060293172 and 20050171237, each of which is
hereby incorporated herein by reference.
[0052] As described below, curing agents and toughening agents may
include epoxy functional groups. These epoxy-containing curing
agents and toughening agents should not be considered herein part
of the above described epoxy resins.
[0053] Phenolic Resins
[0054] Phenolic resins useful in some embodiments disclosed herein
may include any aldehyde condensate resins derived from aldehydes
such as methanol, ethanal, benzaldehyde or furfuraldehyde and
phenols such as phenol, cresols, dihydric phenols, chlorphenols and
C.sub.1-9 alkyl phenols, such as phenol, 3- and 4-cresol (1-methyl,
3- and 4-hydroxy benzene), catechol (2-hydroxy phenol), resorcinol
(1,3-dihydroxy benzene) and quinol (1,4-dihydroxy benzene). In some
embodiments, phenolic resins may include cresol and novolac
phenols.
[0055] Phenolic resins useful in embodiments disclosed herein
include the reaction products of phenolic compounds, such as
mono-functional phenols, di-functional phenols, and multi- or
poly-functional phenols, and an aldehyde, such as formaldehyde.
Examples of mono-functional phenols include phenol; cresol;
2-bromo-4-methylphenol; 2-allyphenol; 1,4-aminophenol; and the
like. Examples of di-functional phenols (polyphenolic compounds)
include phenolphthalane; biphenol; 4-4'-methylene-di-phenol;
4-4'-dihydroxybenzophenone; bisphenol-A;
1,8-dihydroxyanthraquinone; 1,6-dihydroxnaphthalene;
2,2'-dihydroxyazobenzene; resorcinol; fluorene bisphenol; and the
like. Examples of tri-functional phenols include 1,3,5-trihydroxy
benzene and the like. Polyvinyl phenol may also be a suitable
phenolic resin. Phenolic resins are disclosed in, for example, U.S.
Pat. No. 6,207,786.
[0056] Phenolic resins used in some embodiments may have a low
formaldehyde to phenol ratio. For example, a two part system having
a long shelf and pot life, using formaldehyde-free curing
technology and being non-corrosive to dies, having a low solvent
content and generating no water cure may be used. For example,
.sub.the phenolic resins disclosed in U.S. Patent Application
Publication Nos. 20050009980 and 20050054787 may be used.
[0057] Cyanate Ester Based Resins
[0058] Cyanate ester resins useful in embodiments disclosed herein
may include one or more compounds of the general formula
NCOAr(Y.sub.xAr.sub.m).sub.qOCN and oligomers and/or polycyanate
esters and combinations thereof wherein each Ar is independently a
single or fused aromatic or substituted aromatics and combinations
thereof and therebetween nucleus linked in the ortho, meta and/or
para position; x is an integer from 0 to 2; and m and q are each
independently an integer from 0 to 5. Y is a linking unit selected
from the group consisting of oxygen, carbonyl, sulphur, sulphur
oxides, chemical bond, aromatic linked in ortho, meta and/or para
positions and/or CR.sub.1R.sub.2, P(R.sub.3R.sub.4R.sub.4'R.sub.5),
or Si(R.sub.3R.sub.4R.sub.4'R.sub.6). R.sub.1 and R.sub.2 are
independently hydrogen, halogenated alkanes, such as the
fluorinated alkanes, and/or substituted aromatics and/or
hydrocarbon units wherein said hydrocarbon units are singularly or
multiply linked and consist of up to 20 carbon atoms for each
R.sub.1 and/or R.sub.2. R.sub.3 is alkyl, aryl, alkoxy or hydroxyl.
R'.sub.4 may be equal to R.sub.4 and has a singly linked oxygen or
chemical bond. R.sub.5 has a doubly linked oxygen or chemical bond.
R.sub.5 and R.sub.6 are defined similar to R.sub.3 above.
Optionally, the thermoset can consist essentially of cyanate esters
of phenol/formaldehyde derived novolacs or dicyclopentadiene
derivatives thereof, an example of which is XU71787 sold by the Dow
Chemical Company, Midland, Mich.
[0059] In one embodiment disclosed herein, the cyanate ester may
include bis(4-cyanatophenyl)methane
bis(3-methyl-4-cyanatophenyl)methane,
bis(3-ethyl-4-cyanatophenyl)methane,
bis(3,5-dimethyl-4-cyanatophenyl)methane, 1,1
-bis(4-cyanatophenyl)ethane, 2,2-bis(4-cyanatophenyl)propane,
2,2-bis(4-cyanatophenyl)1,1,1,3,3,3-hexafluoropropane,
di(4-cyanatophenyl)ether, di(4-cyanatophenyl)thio ether,
4,4-dicyanatobiphenyl,
1,3-bis(4-cyanatophenyl-1-(1-methylethylidene))benzene,
1,4-bis(4-cyanatophenyl-1-(1-methylethylidene))benzene and
resorcinol dicyanate. Other cyanate esters may include the cyanate
ester of phenol formaldehyde novolak, cyanate ester of phenol
dicyclopentadiene novolak, 1,1,1-tris(4-cyanatophenyl)ethane.
[0060] Cyanate ester prepolymers that may be used in the present
invention are prepolymers produced by partial curing of the cyanate
ester in the presence or absence of a catalyst. A typical example
of such a cyanate ester prepolymer is partially cured
bis(3,5-dimethyl-4-cyanatophenyl)methane, sold under the tradename
AROCY M-20 by Ciba. Other cyanate esters are described in, for
example, U.S. Pat. Nos. 7,115,681, 7,026,411, 6,403,229 and
6,194,495, each of which are incorporated herein by reference.
[0061] Curing Agent/Hardener
[0062] Hardeners and curing agents may be provided for promoting
the cure of the above described thermosetting resins. For example,
a hardener or curing agent may be provided for promoting
crosslinking of the epoxy resin composition to form a polymer
composition. The hardeners and curing agents described herein may
be used individually or as a mixture of two or more.
[0063] Curing agents may include primary and secondary polyamines
and their adducts, anhydrides, and polyamides. For example,
polyfunctional amines may include aliphatic amine compounds such as
diethylene triamine (D.E.H. 20, available from The Dow Chemical
Company, Midland, Mich.), triethylene tetrarnine (D.E.H. 24,
available from The Dow Chemical Company, Midland, Mich.),
tetraethylene pentamine (D.E.H. 26, available from The Dow Chemical
Company, Midland, Mich.), as well as adducts of the above amines
with epoxy resins, diluents, or other amine-reactive compounds.
Aromatic amines, such as metaphenylene diamine and diamine diphenyl
sulfone, aliphatic polyamines, such as amino ethyl piperazine and
polyethylene polyamine, and aromatic polyamines, such as
metaphenylene diamine, diamino diphenyl sulfone, and diethyltoluene
diamine, may also be used.
[0064] Anhydride curing agents may include, for example, nadic
methyl anhydride, hexahydrophthalic anhydride, trimellitic
anhydride, dodecenyl succinic anhydride, phthalic anhydride, methyl
hexahydrophthalic anhydride, tetrahydrophthalic anhydride, and
methyl tetrahydrophthalic anhydride, among others.
[0065] The hardener or curing agent may include a phenol-derived or
substituted phenol- derived novolac or an anhydride. Non-limiting
examples of suitable hardeners include phenol novolac hardener,
cresol novolac hardener, dicyclopentadiene phenol hardener,
limonene type hardener, anhydrides, and mixtures thereof.
[0066] In some embodiments, the phenol novolac hardener may contain
a biphenyl or naphthyl moiety. The phenolic hydroxy groups may be
attached to the biphenyl or naphthyl moiety of the compound. This
type of hardener may be prepared, for example, according to the
methods described in EP915118A1. For example, a hardener containing
a biphenyl moiety may be prepared by reacting phenol with
bismethoxy-methylene biphenyl.
[0067] In other embodiments, curing agents may include
dicyandiamide and diaminocyclohexane. Curing agents may also
include imidazoles, their salts, and adducts. These epoxy curing
agents are typically solid at room temperature. Examples of
suitable imidazole curing agents are disclosed in EP906927A1. Other
curing agents include aromatic amines, aliphatic amines,
anhydrides, and phenols.
[0068] In some embodiments, the curing agents may be an amino
compound having a molecular weight up to 500 per amino group, such
as an aromatic amine or a guanidine derivative. Examples of amino
curing agents include 4-chlorophenyl-N,N-dimethyl-urea and
3,4-dichlorophenyl-N,N-dimethyl-urea.
[0069] Other examples of curing agents useful in embodiments
disclosed herein include: 3,3'- and 4,4'-diaminodiphenylsulfone;
methylenedianiline;
bis(4-amino-3,5-dimethylphenyl)-1,4-diisopropylbenzene available as
EPON 1062 from Shell Chemical Co.; and
bis(4-aminophenyl)-1,4-diisopropylbenzene available as EPON 1061
from Shell Chemical Co.
[0070] Thiol curing agents for epoxy compounds may also be used,
and are described, for example, in U.S. Pat. No. 5,374,668. As used
herein, "thiol" also includes polythiol or polymercaptan curing
agents. Illustrative thiols include aliphatic thiols such as
methanedithiol, propanedithiol, cyclohexanedithiol,
2-mercaptoethyl-2,3-dimercaptosuceinate,
2,3-dimercapto-1-propanol(2-mercaptoacetate), diethylene glycol
bis(2-mercaptoacetate), 1,2-dimercaptopropyl methyl ether,
bis(2-mercaptoethyl)ether, trimethylolpropane tris(thioglycolate),
pentaerythritol tetra(mercaptopropionate), pentaerythritol
tetra(thioglycolate), ethyleneglycol dithioglycolate,
trimethylolpropane tris(beta-thiopropionate), tris-mercaptan
derivative of tri-glycidyl ether of propoxylated alkane, and
dipentaerythritol poly(beta-thiopropionate); halogen-substituted
derivatives of the aliphatic thiols; aromatic thiols such as di-,
tris- or tetra-mercaptobenzene, bis-, tris- or
tetra-(mercaptoalkyl)benzene, dimercaptobiphenyl, toluenedithiol
and naphthalenedithiol; halogen-substituted derivatives of the
aromatic thiols; heterocyclic ring-containing thiols such as
amino-4,6-dithiol-sym-triazine, alkoxy-4,6-dithiol-sym-triazine,
aryloxy-4,6-dithiol-sym-triazine and 1,3,5-tris(3-mercaptopropyl)
isocyanuratc; halogen-substituted derivatives of the heterocyclic
ring-containing thiols; thiol compounds having at least two
mercapto groups and containing sulfur atoms in addition to the
mercapto groups such as bis-, tris- or
tetra(mercaptoalkylthio)benzene, bis-, tris- or
tetra(mercaptoalkylthio)alkane, bis(mercaptoalkyl) disulfide,
hydroxyalkylsulfidebis(mereaptopropionate),
hydroxyalkylsulfidebis(mercaptoacetate), mercaptoethyl ether
bis(mercaptopropionate), 1,4-dithian-2,5-diolbis(mercaptoacetate),
thiodiglycolic acid bis(mercaptoalkyl ester), thiodipropionie acid
bis(2-mercaptoalkyl ester), 4,4-thiobutyric acid
bis(2-mercaptoalkyl ester), 3,4-thiophenedithiol, bismuththiol and
2,5-dimercapto-1,3,4-thiadiazol.
[0071] Aliphatic polyamines that are modified by adduction with
epoxy resins, acrylonitrile, or (meth)acrylates may also be
utilized as curing agents. In addition, various Mannich bases can
be used. Aromatic amines wherein the amine groups are directly
attached to the aromatic ring may also be used.
[0072] The suitability of the curing agent for use herein may be
determined by reference to manufacturer specifications or routine
experimentation. Manufacturer specifications may be used to
determine if the curing agent is an amorphous solid or a
crystalline solid at the desired temperatures for mixing with the
liquid or solid epoxy. Alternatively, the solid curing agent may be
tested using simple crystallography to determine the amorphous or
crystalline nature of the solid curing agent and the suitability of
the curing agent for mixing with the epoxy resin in either liquid
or solid form.
[0073] In some embodiments, the hardener may be used at a
concentration to achieve a molar ratio of the respective reactive
groups (thermoset resin to hardener) between about 0.2 and about 5;
between about 0.5 and 2 in other embodiments; between about 0.8 and
1.25 in other embodiments; and between about 0.9 and 1.1 in yet
other embodiments.
[0074] Chain Extenders
[0075] Chain extenders may be used as an optional component in
compositions described herein. Compounds which may be used in
embodiments of the curable compositions disclosed herein as a chain
extender include any compound having an average of about 2 hydrogen
atoms per molecule which are reactive with vicinal epoxy groups. In
some embodiments, dihydric and polyhydric phenolic compounds may be
used, including, for example, xanthenes, phthaleins and
sulfonphthaleins having two phenolic hydroxyl groups.
[0076] In some embodiments, chain extenders may include phenolic
hydroxyl-containing compounds such as, for example, resorcinol,
catechol, hydroquinone, bisphenol A, bisphenol K, bisphenol S,
tetramethylbisphenol A, tetratertiarybutylbisphenol A,
tetrabromobisphenol A, phenolphthalein, phenolsulfonphthalein,
fluorescein, 4,4'-dihydroxybiphenyl,
3,5,3',5-tetramethyl-4,4'-dihydroxybiphenyl,
3,5,3',5'-tetrabromodihydroxybiphenyl,
3,5,3',5'-tetramethyl-2,6,2',6'-tetrabromo-4,4'-dihydroxybiphenyl,
reaction products of dicyclopentadiene or oligomers thereof and a
phenolic compound, mixtures thereof and the like. Other suitable
chain extenders may include, for example, aniline, toluidine,
butylamine, ethanolamine, N,N'-dimethyl phenylene diamine, phthalic
acid, adipic acid, fumaric acid, 1,2-dimereapto-4-methylbenzene,
diphenyloxide dithiol, 1,4-butanedithiol, mixtures thereof and the
like.
[0077] In other embodiments, the chain extender may be a
nitrogen-containing monomer for example, an isocyanate, and amine
or amide. In some embodiments, chain extenders may include
epoxy-polyisocyanate compounds as described in WO 99/00451 and U.S.
Pat. No. 5,112,932, each of which are incorporated herein by
reference. Isocyanate compounds useful as chain extenders include,
for example MDI, TDI and isomers thereof.
[0078] The nitrogen-containing chain extender may also be, for
example an amine- or amino amide-containing compound which forms
epoxy-terminated amine compounds having two N--H bonds capable of
reacting with an epoxy group. Amine-containing chain extenders
include, for example, mono-primary amines of the general formula
R--NH.sub.2 wherein R is alkyl, cycloalkyl or aryl moieties;
di-secondary amines of the general formula R--NH--R'--NH--R''
wherein R, R' and R'' are alkyl, cycloalkyl or aryl moieties; and
heterocyclic di-secondary amines wherein one or both of the N atoms
is part of a nitrogen containing heterocyclic compound. Examples of
amine-containing chain extender may include 2,6-dimethyl
cyclohexylamine or 2,6-xylidine (1-amino-2,6-dimethylbenzene).
Aromatic diamines may be used in other embodiments, such as, for
example, with 3,3'-dichloro-4,4'-diaminodiphenyl methane or
4,4'-methylene-bis(3-chloro-2,6-diethylaniline) and
3,3-dimethyl-4,4'-diaminodiphenyl.
[0079] Amino amide-containing compounds useful as chain extenders
include, for example, derivatives of carboxylic acid amides as well
as derivatives of sulfonic acid amides having additionally one
primary or two secondary amino groups. Examples of such compounds
include amino-aryl carboxylic acid amides and
amino-arylsulfonamides, such as sulfanilamide (4-amino
benzenesulfonamide) and anthranilamide(2-aminobenzamide).
[0080] The amount of the chain extender may be used in some
embodiments, in an amount from 1 to 40 weight percent, based on the
epoxy resin. In other embodiments, the chain extender may be used
in an amount ranging from 2 to 35 weight percent; from 3 to 30
weight percent in other embodiments; and from 5 to 25 weight
percent in yet other embodiments, each based on the amount of epoxy
resin.
[0081] Solvent
[0082] Another optional component, which may be added to the
curable epoxy resin composition, is a solvent or a blend of
solvents. The solvent used in the epoxy resin composition may be
miscible with the other components in the resin composition. The
solvent used may be selected from those typically used in making
electrical laminates. Examples of suitable solvents employed in the
present invention include, for example, ketones, ethers, acetates,
aromatic hydrocarbons, cyclohexanone, dimethylformamide, glycol
ethers, and combinations thereof.
[0083] Solvents for the catalyst and the inhibitor may include
polar solvents. Lower alcohols having from 1 to 20 carbon atoms,
such as, for example, methanol, provide good solubility and
volatility for removal from the resin matrix when prepregs are
formed. Other useful solvents may include, for example,
N,-methyl-2-pyrrolidone, dimethylsulfoxide, dimethylformamide,
tetrahydrofuran, 1,2-propane diol, ethylene glycol and
glycerine.
[0084] The total amount of solvent used in the curable epoxy resin
composition generally may range from about 1 to about 65 weight
percent in some embodiments. In other embodiments, the total amount
of solvent may range from 2 to 60 weight percent; from 3 to 50
weight percent in other embodiments; and from 5 to 40 weight
percent in yet other embodiments.
[0085] Catalyst
[0086] In some embodiments, a catalyst may be used to promote the
reaction between the epoxy resin component and the curing agent or
hardener. Catalysts may include, for example, an imidazole or a
tertiary amine. Other catalysts may include tetraalkylphosphonium
salts, tetraalkylammonium salts, and the like; benzyl
dimethylamine; dimethyl aminomethyl phenol; and amines, such as
triethylamine, imadazole derivatives, and the like.
[0087] Tertiary amine catalysts are described, for example, in U.S.
Pat. No. 5,385,990, incorporated herein by reference. Illustrative
tertiary amines include methyldiethanolamine, triethanolamine,
diethylaminopropylamine, benzyldimethyl amine,
m-xylylenedi(dimethylamine), N,N'-dimethylpiperazine,
N-methylpyrrolidine, N-methyl hydroxypiperidine,
N,N,N',N'-tetramethyldiaminoethane,
N,N,N',N',N'-pentamethyldiethylenetriamine, tributyl amine,
trimethyl amine, diethyldecyl amine, triethylene diamine, N-methyl
morpholine, N,N,N'N'-tetramethyl propane diamine, N-methyl
piperidine, N,N'-dimethyl-1,3-(4-piperidino)propane, pyrridine and
the like. Other tertiary amines include 1,8-diazobicyclo
[5.4.0]undec-7-ene, 1,8-diazabicyclo [2.2.2]octane,
4-dimethylaminopyrridine, 4-(N-pyrrolidino)pyrridine, triethyl
amine and 2,4,6-tris(dimethylaminomethyl)phenol.
[0088] Catalysts may include imidazole compounds including
compounds having one imidazole ring per molecule, such as
imidazole, 2-methylimidazole, 2-ethyl-4-methylimidazole,
2-undecylimidazole, 2-heptadecylimidazole, 2-phenylimidazole,
2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole,
2-ethylimidazole, 2-isopropylimidazole, 2-phenyl-4-benzylimidazole,
1-cyanoethyl-2-methylimidazole,
1-cyanoethyl-2-ethyl-4-methylimidazole,
1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-isopropylimidazole,
1-cyanoethyl-2-phenyl imidazole,
2,4-diamino-6-[2'-methylimidazolyl-(1)']ethyl-s-triazine,
2,4-diamino-6-[2'-ethyl-4-methylimidazolyl-(1)']-ethyl-s-triazine,
2,4-diamino-6-[2'-undecylimidazolyl-(1)']-ethyl-s-triazine,
2-methylimidazolium-isocyanuric acid adduct, 2-phenyl
imidazolium-isocyanuric acid adduct,
1-aminoethyl-2-methylimidazole,
2-phenyl-4,5-dihydroxymethylimidazole,
2-phenyl-4-methyl-5-hydroxymethylimidazole,
2-phenyl-4-benzyl-5-hydroxymethylimidazole and the like; and
compounds containing 2 or more imidazole rings per molecule which
are obtained by dehydrating above-named hydroxymethyl- containing
imidazole compounds such as 2-phenyl-4,5-dihydroxymethylimidazole,
2-phenyl-4 -methyl-5-hydroxymethylimidazole and
2-phenyl-4-benzyl-5-hydroxymethylimidazole; and condensing them by
deformaldehyde reaction, e.g.,
4,4'-methylene-bis-(2-ethyl-5-methylimidazole), and the like.
[0089] Catalysts that may be used with cyanate ester resins, for
example, may include carboxylate salts, phenols, alcohols, amines,
urea derivatives, imidazoles, and metal chelates. In some
embodiments, the catalyst may include octoate, carboxylate, or
acetylacetonate salts of zinc, cobalt, copper, manganese, iron,
nickel, or aluminum.
[0090] Catalysts that may be used to form phenolic resins may
include, for example, various amines and hydroxides, examples of
which include caustic sodium hydroxide, triethylamine, ammonia,
lithium hydroxide, ammonium hydroxide and triethanolamine.
[0091] In some embodiments, combinations of two or more catalyst
may be used. In other embodiments, at least one catalyst used may
react at a temperature greater than that of the curing agent used
in the composition. For example, where a curing agent initiates
reaction at a temperature of 150.degree. C., the catalyst may
initiate react at 180.degree. C.
[0092] The concentration of catalyst used in curable compositions
disclosed herein may be between about 10 ppm and about 5 percent by
weight based on the total weight of thermosetting resin and
hardener, if used; between about 100 ppm and 3 percent by weight in
other embodiments; and between 1000 ppm and 2 percent by weight in
yet other embodiments.
[0093] High Temperature Resistant Thermoplastics
[0094] High temperature resistant thermoplastics may be combined
with the above described thermosetting resins to improve at least
one of dampening ranges, performance at high temperatures, and
processability. For example, high temperature resistant
thermoplastics may include polyetherimides, polyphenylene ether,
polyoxyphenylenes, polysulphone, syndiotactic polystyrene, polyaryl
ether ketones, polycarbonates, acetals, polyimides, and polyarylene
sulfides, among others.
[0095] Examples of polyphenylene ethers and a method for their
production are described in, for example, U.S. Pat. No. 4,734,485.
Examples of polyarylene sulfides are described in, for example,
U.S. Pat. No. 5,064,884. Examples of polyaryl ether ketones are
described in, for example, U.S. Pat. No. 5,122,588.
[0096] Polyetherimide resins may include, for example, the reaction
product formed by melt polymerization of
2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride with one
or more of paraphenylene diamine and metaphenylene diamine, such as
disclosed in U.S. Pat. No. 6,753,365. Other polyetherimides resins
may include those described in, for example, U.S. Pat. Nos.
6,239,232, 6,403,684, and 6,011,122, among others. Other high
temperature resistant thermoplastics are described in, for example,
U.S. Pat. Nos. 6,548,608, 3,984,604, 6,894,102, 6,890,973,
6,875,804, 6,008,293, and 5,352,727, among others.
[0097] The high temperature resistant thermoplastic resin used in
embodiments of the thermosetting compositions disclosed herein may
be selected from any thermoplastic resin that does not undergo a
thermal decomposition of more than about 5 weight percent at about
100.degree. C. In other embodiments, the thermoplastic resin does
not undergo a thermal decomposition of more than about 5 weight
percent at about 150.degree. C.; at about 200.degree. C. in yet
other embodiments.
[0098] The concentration of high temperature resistant
thermoplastic resins may be between about 0.1 percent and 60
percent, based on the total weight of the thermosetting
composition; between about 0.5 percent and 50 percent by weight in
other embodiments; between about 1 percent and 40 percent by weight
in other embodiments; between about 2 percent and about 30 percent
by weight in other embodiments; and between about 5 percent and 20
percent by weight in yet other embodiments.
[0099] In some embodiments, the resulting thermoset dampener
composition has distinct phases, including a thermoset resin phase
and a high temperature thermoplastic resin phase. Compositions
disclosed herein should maintain the concentration of high
temperature thermoplastic resin below a maximum concentration, such
that the cured thermoset resin forms the continuous phase. In some
embodiments, the thermoplastic phase forms discretely dispersed
particles within the thermoset network such that the size of the
dispersed thermoplastic domains is less than about 100 microns;
less than 50 microns in other embodiments; less than 20 microns in
other embodiments; less than 10 microns in other embodiments; and
less than 5 microns in yet other embodiments.
[0100] Optional Additives
[0101] The composition may also include optional additives and
fillers conventionally found in thermoset or epoxy systems. For
example, thermoset compositions and dampener materials disclosed in
various embodiments may include toughening agents, curing
inhibitors, wetting agents, colorants, processing aids, UV blocking
compounds, fluorescent compounds, and other additives.
[0102] Additives and fillers may include silica, glass, talc,
quartz, metal powders, titanium dioxide, wetting agents, pigments,
coloring agents, mold release agents, coupling agents, flame
retardants, ion scavengers, UV stabilizers, flexibilizing agents,
and tackifying agents. Additives and fillers may also include fumed
silica, aggregates such as glass beads, polytetrafluoroethylene,
polyol resins, polyester resins, phenolic resins, graphite,
molybdenum disulfide, abrasive pigments, viscosity reducing agents,
boron nitride, mica, nucleating agents, and stabilizers, among
others. Fillers and modifiers may be preheated to drive off
moisture prior to addition to the epoxy resin composition.
Additionally, these optional additives may have an effect on the
properties of the composition, before and/or after curing, and
should be taken into account when formulating the composition and
the desired reaction product.
[0103] In other embodiments, compositions disclosed herein may
include toughening agents. Toughening agents function by forming a
secondary phase within the polymer matrix. This secondary phase is
rubbery and hence is capable of crack growth arrestment, providing
improved impact toughness. Toughening agents may include
polysulfones, silicon-containing elastomeric polymers,
polysiloxanes, and other rubber toughening agents known in the
art.
[0104] Inorganic fillers used in embodiments disclosed herein may
have at least one average dimension below about 1 mm; below about
100 microns in other embodiments; below about 50 microns in other
embodiments; below 10 microns in other embodiments; above 2 nm in
other embodiments; above 10 nm in other embodiments; above 20 nm in
other embodiments; and above 50 nm in yet other embodiments.
[0105] In other embodiments, thermosetting compositions disclosed
herein may include fibrous reinforcement materials, such as
continuous and/or chopped fibers. The fibrous reinforcement
material may include glass fibers, carbon fibers, or organic fibers
such as polyamide, polyimide, and polyester. The concentration of
fibrous reinforcements used in embodiments of the thermosetting
compositions may be between about 1 percent to about 95 percent by
weight, based on the total weight of the composition; between about
5 percent and 90 percent by weight in other embodiments; between
about 10 percent and 80 percent in other embodiments; between about
20 percent and 70 percent in other embodiments; and between 30
percent and 60 percent in yet other embodiments.
[0106] In other embodiments, compositions disclosed herein may
include nanofillers. Nanofillers may include inorganic, organic, or
metallic, and may be in the form of powders, whiskers, fibers,
plates or films. The nanofillers may be generally any filler or
combination of fillers having at least one dimension (length,
width, or thickness) from about 0.1 to about 100 nanometers. For
example, for powders, the at least one dimension may be
characterized as the grain size; for whiskers and fibers, the at
least one dimension is the diameter; and for plates and films, the
at least one dimension is the thickness. Clays, for example, may be
dispersed in an epoxy resin-based matrix, and the clays may be
broken down into very thin constituent layers when dispersed in the
epoxy resin under shear. Nanofillers may include clays,
organo-clays, carbon nanotubes, nanowhiskers (such as SiC),
SiO.sub.2, elements, anions, or salts of one or more elements
selected from the s, p, d, and f groups of the periodic table,
metals, metal oxides, and ceramics.
[0107] The concentration of any of the above described additives,
when used in the thermosetting compositions described herein, may
be between about 1 percent and 95 percent, based on the total
weight of the composition; between 2 percent and 90 percent in
other embodiments; between 5 percent and 80 percent in other
embodiments; between 10 percent and 60 percent in other
embodiments, and between 15 percent and 50 percent in yet other
embodiments.
[0108] Substrates
[0109] The substrate or object is not subject to particular
limitation. As such, substrates may include metals, such as
stainless steel, iron, steel, copper, zinc, tin, aluminium, alumite
and the like; alloys of such metals, and sheets which are plated
with such metals and laminated sheets of such metals. Substrates
may also include polymers, glass, and various fibers, such as, for
example, carbon/graphite; boron; quartz; aluminum oxide; glass such
as E glass, S glass, S-2 GLASS.RTM. or C glass; and silicon carbide
or silicon carbide fibers containing titanium. Commercially
available fibers may include: organic fibers, such as KEVLAR;
aluminum oxide-containing fibers, such as NEXTEL fibers from 3M;
silicon carbide fibers, such as NICALON from Nippon Carbon; and
silicon carbide fibers containing titanium, such as TYRRANO from
Ube. In some embodiments, the substrate may be coated with a
compatibilizer to improve the adhesion of the curable or cured
composition to the substrate.
[0110] In selected embodiments, the curable compositions described
herein may be used as coatings for substrates that cannot tolerate
high temperatures. In other embodiments, the curable compositions
may be used with substrates whose dimensions and shape make it
difficult to apply homogeneous heating, such as windmill blades,
for example.
[0111] Composites and Coated Structures
[0112] The curable compositions and the composites described herein
may be produced conventionally, accounting for the alteration in
the epoxy resin compositions before they are cured as described
above, including the stoichiometric excess of epoxy resin and the
temperature stable catalyst. In some embodiments, composites may be
formed by curing the curable compositions disclosed herein. In
other embodiments, composites may be formed by applying a curable
epoxy resin composition to a substrate or a reinforcing material,
such as by impregnating or coating the substrate or reinforcing
material, and curing the curable composition.
[0113] The above described curable compositions may be in the form
of a powder, slurry, or a liquid. After a curable composition has
been produced, as described above, it may be disposed on, in, or
between the above described substrates, before, during, or after
cure of the curable composition.
[0114] For example, a composite may be formed by coating a
substrate with a curable composition. Coating may be performed by
various procedures, including spray coating, curtain flow coating,
coating with a roll coater or a gravure coater, brush coating, and
dipping or immersion coating.
[0115] In various embodiments, the substrate may be monolayer or
multi-layer. For example, the substrate may be a composite of two
alloys, a multi-layered polymeric article, and a metal-coated
polymer, among others, for example. In other various embodiments,
one or more layers of the curable composition may be disposed on a
substrate. For example, a substrate coated with a polyurethane-rich
curable composition as described herein may additionally be coated
with an epoxy resin-rich curable composition. Other multi-layer
composites, formed by various combinations of substrate layers and
curable composition layers are also envisaged herein.
[0116] In some embodiments, the heating of the curable composition
may be localized, such as to avoid overheating of a
temperature-sensitive substrate, for example. In other embodiments,
the heating may include heating the substrate and the curable
composition.
[0117] In one embodiment, the curable compositions, composites, and
coated structures described above may be cured by heating the
curable composition to a temperature sufficient to initiate
reaction of the curing agent. During the initial cure, secondary
hydroxyl groups may be formed as the curing agent reacts. Following
at least partial reaction of the curing agent and epoxy, the
temperature of the curable composition, composite, or coated
structure may be increased to a temperature sufficient for the
catalyst to catalyze the reaction of the secondary hydroxyl groups
with the excess epoxy resin. In this manner, the stoichiometric
excess of epoxy may be reacted without significant degradation of
the epoxy thermoset.
[0118] In some embodiments, the additional crosslinking that forms
during the reaction of the excess epoxy may decrease the bulk
density of the epoxy thermoset. In other embodiments, the
additional crosslinking may increase the fracture toughness of the
epoxy thermoset. In yet other embodiments, the reaction of the
stoichiometric excess of epoxy may avoid the deleterious effects
that unreacted epoxy may have on the thermoset composition, as
described in the prior art, resulting in a thermoset composition
having one or more of adequate or improved heat resistance, solvent
resistance, low moisture absorption, reflow reliability, electrical
properties, glass transition temperature, and adhesion, among
others.
[0119] Curing of the curable compositions disclosed herein may
require a temperature of at least about 30.degree. C., up to about
250.degree. C., for periods of minutes up to hours, depending on
the epoxy resin, curing agent, and catalyst, if used. In other
embodiments, curing may occur at a temperature of at least
100.degree. C., for periods of minutes up to hours. Post-
treatments may be used as well, such post-treatments ordinarily
being at temperatures between about 100.degree. C. and 250.degree.
C.
[0120] In some embodiments, curing may be staged to prevent
exotherms. Staging, for example, includes curing for a period of
time at a temperature followed by curing for a period of time at a
higher temperature. Staged curing may include two or more curing
stages, and may commence at temperatures below about 180.degree. C.
in some embodiments, and below about 150.degree. C. in other
embodiments.
[0121] In some embodiments, curing temperatures may range from a
lower limit of 30.degree. C., 40.degree. C., 50.degree. C.,
60.degree. C., 70.degree. C., 80.degree. C., 90.degree. C.,
100.degree. C., 110.degree. C., 120.degree. C., 130.degree. C.,
140.degree. C., 150.degree. C., 160.degree. C., 170.degree. C., or
180.degree. C. to an upper limit of 250.degree. C., 240.degree. C.,
230.degree. C., 220.degree. C., 210.degree. C., 200.degree. C.,
190.degree. C., 180.degree. C., 170.degree. C., 160.degree. C.,
where the range may be from any lower limit to any upper limit.
[0122] The curable compositions disclosed herein may be useful in
composites containing high strength filaments or fibers such as
carbon (graphite), glass, boron, and the like. Composites may
contain from about 30% to about 70%, in some embodiments, and from
40% to 70% in other embodiments, of these fibers based on the total
volume of the composite.
[0123] Fiber reinforced composites, for example, may be formed by
hot melt prepregging. The prepregging method is characterized by
impregnating bands or fabrics of continuous fiber with a
thermosetting epoxy resin composition as described herein in molten
form to yield a prepreg, which is laid up and cured to provide a
composite of fiber and thermoset resin.
[0124] Other processing techniques can be used to form composites
containing the epoxy-based compositions disclosed herein. For
example, filament winding, solvent prepregging, and pultrusion are
typical processing techniques in which the uncured epoxy resin may
be used. Moreover, fibers in the form of bundles may be coated with
the uncured epoxy resin composition, laid up as by filament
winding, and cured to form a composite.
[0125] The curable compositions and composites described herein may
be useful as adhesives, structural and electrical laminates,
coatings, castings, structures for the aerospace industry, as
circuit boards and the like for the electronics industry, windmill
blades, as well as for the formation of skis, ski poles, fishing
rods, and other outdoor sports equipment. The epoxy compositions
disclosed herein may also be used in electrical varnishes,
encapsulants, semiconductors, general molding powders, filament
wound pipe, storage tanks, liners for pumps, and corrosion
resistant coatings, among others.
EXAMPLES
Examples A1 and A2
[0126] Examples A1 and A2 are prepared by mixing resins and
hardeners, as indicated in Table 1, in suitable solvents at ambient
temperatures. The thermosetting resin PN is a low molecular weight
phenol novolac with a phenolic equivalent weight, PhEW, of 104; the
hardener ZE is an oxazolidine of 5-ethyl-1-aza-3,
7-dioxabicyclo[3.3.0]octane. For higher viscosity formulations,
formulations are warmed up to a temperature between 60.degree. C.
and 80.degree. C. to lower the viscosity for admixture of the
components. The mixtures are degassed, and castings are prepared by
pouring the formulations in open molds. The castings are then cured
in a ventilated oven for 10 minutes at 150.degree. C., 10 minutes
at 180.degree. C., and 10 minutes at 200.degree. C. Following cure,
the castings are allowed to cool to ambient temperature.
Formulations and properties of the cured compositions are given in
Table 1.
TABLE-US-00001 TABLE 1 Example A1 A2 Formulation PN (g) 68.5 65 ZE
(g) 31.5 35 Properties of the Cured Composition T.alpha., measured
by tan .delta. peak (.degree. C.) 202 235 Height of tan .delta.
peak 0.36 0.28 Width of tan .delta. peak at half-height (.degree.
C.) 45 60
Examples A3 and A4
[0127] Examples A3 and A4 are prepared by mixing resins, hardeners,
and catalysts as indicated in Table 2, in suitable solvents.
Thermosetting epoxy resin E1 is a glycidyl ether of bisphenol A
with an epoxy equivalent weight, EEW, of 180; thermosetting epoxy
resin E2 is an epoxy novolac with an epoxy equivalent weight, EEW,
of 180; triazine T1 is a triazine homopolymer of
2,2-bis(4-cyanatophenyl)propane; bismaleimide B1 is a
diphenylmethane-4,4'-bismaleimide; catalyst C1 is a
zinc-bis(2-ethylhexanoate) in MEK (methyl ethyl ketone) solution.
The formulations are warmed up to a temperature between 100.degree.
C. and 120.degree. C. to lower the viscosity for admixture of the
components. The castings are prepared by pouring the formulations
in open molds. The castings are then cured in a ventilated oven for
60 minutes at 170.degree. C. and 90 minutes at 200.degree. C.
Following cure, the castings are allowed to cool to ambient
temperature. Formulations and properties of the cured compositions
are given in Table 2.
TABLE-US-00002 TABLE 2 Example A3 A4 Formulation Epoxy Resin E1 (g)
38.4 0 Epoxy Resin E2 (g) 0 38.4 Triazine T1 (g) 36.9 36.9
Bismaleimide B1 (g) 24.5 24.5 Catalyst C1 (10% non volatiles in
MEK) (g) 0.2 0.2 Properties of the Cured Composition T.alpha.,
measured by tan .delta. peak (.degree. C.) 257 262 Height of tan
.delta. peak 0.34 0.28 Width of tan .delta. peak at half-height
(.degree. C.) 46 61
Example A5
[0128] Example A5 is prepared by mixing resins, hardeners,
additives, and catalysts as indicated in Table 3. Thermosetting
epoxy resin E2 is a glycidyl ether of bisphenol A with an epoxy
equivalent weight, EEW, of 187; thermosetting epoxy resin E3 is
3,4-Epoxycyelohexylmethyl-3,4-epoxycyclohexane carboxylate with an
epoxy equivalent weight, EEW, of 135; hardener H1 is methyl
hexahydrophthalic anhydride with an anhydride equivalent weight,
AnhEW, of 168; hardener H2 is hexahydrophthalic anhydride with an
anhydride equivalent weight, AnhEW, of 154; catalyst C2 is
1-cyanoethyl-2-ethyl-4-methylimidazole; and filler F1 is a
crystalline silica filler with a median particles size of about 16
micron. The formulation is warmed up to a temperature of about
60.degree. C. to lower the viscosity for admixture of the
components. The mixture is degassed for 15 minutes at 60.degree.
C., and castings are prepared by pouring the formulation in an open
mold. The castings are then cured in a ventilated oven for 95
minutes at 65.degree. C., 75 minutes at 75.degree. C., 80 minutes
at 115.degree. C., and 60 minutes at 150.degree. C. Following cure,
the castings are allowed to cool to ambient temperature.
Formulation and properties of the cured compositions are given in
Table 3.
TABLE-US-00003 Example A5 Formulation Epoxy Resin E2 (g) 6.1 Epoxy
Resin E3 (g) 18.5 Hardener H1 (g) 20.8 Hardener H2 (g) 1.1 Catalyst
C2 (g) 0.2 Silica Filler F1 (g) 53.3 Properties of the Cured
Composition T.alpha., measured by tan .delta. peak (.degree. C.)
178 Height of tan .delta. peak 0.55 Width of tan .delta. peak at
half-height (.degree. C.) 40
Example A6
[0129] 50 g of polypropyleneglycol of average molecular weight
about 425, pre-dried over molecular sieves, plus 123 grams of
anhydrous dichloromethane are placed in a five- necked flask of
sufficient capacity fitted with a mechanical stirrer, reflux
condenser, thermometer, screw-type feed funnel for powders and an
inlet feed tube for dry nitrogen, which is streamed, slowly during
all the succession of operations. The temperature is then adjusted
to and maintained at 20.degree. C. to 25.degree. C. during the
entire process. 11.36 g of powdered potassium iodide dried under
vacuum at 40.degree. C. to 5 O .degree. C. are then fed gradually
into the flask under stirring. The mixture is stirred until it is
clear. Most of the solvent is then removed from the resulting
solution by distillation under atmospheric pressure at a
temperature not exceeding 50.degree. C.-60.degree. C. The residual
dichloromethane is then carefully eliminated with a rotary
evaporator under reduced pressure and again at 50.degree.
C.-60.degree. C. The catalyst prepared in this manner is a
yellowish clear oily liquid at 15.degree. C.-25.degree. C.
[0130] 0.6 grams of the above-formed potassium iodide catalyst is
mixed with 35.3 grams of a diglycidyl ether of bisphenol A having
an epoxy equivalent weight, EEW, of about 185 and 58.5 grams of a
methylene di-isocyanate having a molecular weight of about 143. The
mixture is warmed up to a temperature between 100.degree. C. and
120.degree. C. to lower the viscosity for admixture of the
components. The castings are prepared by pouring the formulation in
an open mold. The castings are then cured in a ventilated oven for
approximately 2 hours at 150.degree. C. Following cure, the
castings are allowed to cool to ambient temperature. Formulations
and properties of the cured compositions, as measured using dynamic
mechanical thermal analysis, are given in Table 4 and FIG. 1.
TABLE-US-00004 TABLE 4 Properties of the Cured Composition
T.alpha., measured by tan .delta. peak (.degree. C.) 200 Height of
tan .delta. peak 0.65 Width of tan .delta. peak at half-height
(.degree. C.) 40
[0131] Advantageously, embodiments disclosed herein may provide for
efficient dampening of vibrations at high temperatures.
Compositions described herein may include both high glass
transition temperatures and high dampening factors. When disposed
on substrates for use in high temperature environments, the
dampener compositions described herein may effectively dampen the
vibrations, resulting in one or more of increased part life and
improved part performance, among other benefits.
[0132] While the disclosure includes a limited number of
embodiments, those skilled in the art, having benefit of this
disclosure, will appreciate that other embodiments may be devised
which do not depart from the scope of the present disclosure.
Accordingly, the scope should be limited only by the attached
claims.
* * * * *