U.S. patent application number 11/642489 was filed with the patent office on 2007-07-05 for elastic methacrylate compositions.
This patent application is currently assigned to IPS Corporation. Invention is credited to Paul C. Briggs, Samuel B. Osae.
Application Number | 20070155899 11/642489 |
Document ID | / |
Family ID | 37944885 |
Filed Date | 2007-07-05 |
United States Patent
Application |
20070155899 |
Kind Code |
A1 |
Briggs; Paul C. ; et
al. |
July 5, 2007 |
Elastic methacrylate compositions
Abstract
A two-part adhesive composition exhibiting improved elasticity
wherein its composition includes one or more acrylate or
methacrylate ester monomers, a sulfur bearing compound, preferably
a sulfonyl chloride, an amine promoter, preferably, an amine
aldehyde reaction product, and a thermoplastic block copolymer
component selected from the group consisting of a. a linear
styrene-butadiene-styrene copolymer b. a radial
styrene-butadiene-styrene block copolymer with a plasticizer, c. a
linear or radial styrene-isoprene-styrene block copolymer, and d. a
linear or radial styrene-butadiene-isoprene-styrene block
copolymer, and mixtures thereof.
Inventors: |
Briggs; Paul C.; (Chapel
Hill, NC) ; Osae; Samuel B.; (Cary, NC) |
Correspondence
Address: |
SCOTT R. COX;LYNCH, COX, GILMAN & MAHAN, P.S.C.
500 WEST JEFFERSON STREET
SUITE 2100
LOUISVILLE
KY
40202
US
|
Assignee: |
IPS Corporation
Compton
CA
|
Family ID: |
37944885 |
Appl. No.: |
11/642489 |
Filed: |
December 20, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60752713 |
Dec 21, 2005 |
|
|
|
Current U.S.
Class: |
525/88 |
Current CPC
Class: |
C08L 53/02 20130101;
C09J 153/02 20130101; C08L 2666/02 20130101; C08L 2666/24 20130101;
C08L 2666/02 20130101; C08L 2666/14 20130101; C08L 51/04 20130101;
C08L 53/02 20130101; C09J 151/04 20130101; C09J 153/02 20130101;
C08L 51/04 20130101; C08L 2666/14 20130101; C09J 153/02 20130101;
C08L 2666/24 20130101; C09J 127/04 20130101; C09J 153/02 20130101;
C08L 2666/04 20130101; C08L 2666/02 20130101; C09J 4/06 20130101;
C09J 153/02 20130101; C09J 133/08 20130101; C09J 151/04 20130101;
C08L 2666/02 20130101; C08L 2666/04 20130101; C08L 2666/02
20130101 |
Class at
Publication: |
525/088 |
International
Class: |
C08L 53/00 20060101
C08L053/00 |
Claims
1. A two-part adhesive composition capable of being mixed in a 1:1
ratio to form elastic or ductile adhesives comprising one or more
acrylate or methacrylate ester monomers, a sulfur bearing compound,
an amine promoter, and a thermoplastic block copolymer component
selected from the group consisting of a. a linear
styrene-butadiene-styrene copolymer, b. a radial
styrene-butadiene-styrene block copolymer with a plasticizer, c. a
linear or radial styrene-isoprene-styrene block copolymer, d. a
linear or radial styrene-butadiene-isoprene-styrene block
copolymer, and mixtures thereof.
2. The two-part adhesive of claim 1 further comprising an adhesion
promoting polymer.
3. The two-part adhesive of claim 2 wherein the adhesion promoting
polymer comprises a chlorinated polymer.
4. The two-part adhesive of claim 3 wherein the chlorinated polymer
is selected from the group consisting of chlorosulfonated
polyethylene, chlorinated polyethylene, polychloroprene polymers
and mixtures thereof.
5. The two-part adhesive of claim 1, wherein the sulfur bearing
compound comprises sulfonyl chloride.
6. The two-part adhesive of claim 1, wherein the amine promoter
comprises an amine aldehyde reaction product or
dihydropyridine.
7. The two-part adhesive of claim 1, further comprising an impact
modifier.
8. The two-part adhesive of claim 7, wherein the impact modifier
comprises a core shell impact modifier.
9. The two-part adhesive of claim 1, wherein the acrylate or
methacrylate ester monomers are selected from the group consisting
of methyl methacrylate monomer, and higher molecular weight
acrylate and methacrylate monomers, wherein the alcohol portion of
the monomer is based on a C.sub.6 or higher hydrocarbon moiety and
mixtures thereof.
10. The two-part adhesive of claim 1, wherein the acrylate or
methacrylate ester monomer comprises lauryl methacrylate.
11. The two-part adhesive composition of claim 1 further comprising
an initiator selected from the group consisting of sulfur bearing
compounds, peroxides and mixtures thereof.
12. The two-part adhesive composition of claim 11, wherein the
peroxides are selected from the group consisting of cumene
hydroperoxide, methyl ethyl ketone peroxide, benzoate esters,
including t-butyl perbenzoate, and mixtures thereof.
13. The two-part adhesive of claim 11, wherein the initiator does
not include benzoyl peroxide.
14. The two-part adhesive composition of claim 1 further comprising
an activator comprising adducts of butyraldehyde and aniline.
15. A two-part adhesive composition capable of being mixed in a 1:1
ratio to form elastic or ductile adhesives comprising from about 20
to about 90% by weight of one or more acrylate or methacrylate
ester monomers, from about 0.02 to about 30% by weight of a sulfur
bearing compound, from about 0.05 to about 10% by weight of an
amine promoter, and from about 5 to about 50% by weight of a
thermoplastic block copolymer component selected from the group
consisting of a. a linear styrene-butadiene-styrene copolymer, b. a
radial styrene-butadiene-styrene block copolymer with a
plasticizer, c. a linear or radial styrene-isoprene-styrene block
copolymer, d. a linear or radial styrene-butadiene-isoprene-styrene
block copolymer, and mixtures thereof.
16. The two-part adhesive composition of claim 15 that does not
include benzoyl peroxide.
17. A two-part adhesive composition capable of being mixed in a 1:1
ratio to form elastic or ductile adhesives comprising from about 20
to about 90% by weight of one or more acrylate or methacrylate
ester monomers, from about 0.02 to about 30% by weight of a sulfur
bearing compound, from about 0.05 to about 10% by weight of an
amine promoter, an adhesion promoter, and from about 5 to about 50%
by weight of a thermoplastic block copolymer component selected
from the group consisting of a. a linear styrene-butadiene-styrene
copolymer, b. a radial styrene-butadiene-styrene block copolymer
with a plasticizer, c. a linear or radial styrene-isoprene-styrene
block copolymer, d. a linear or radial
styrene-butadiene-isoprene-styrene block copolymer, and mixtures
thereof, but without the use of benzoyl peroxide.
18. A process for the formation of an adhesive with an 1:1 ratio
comprising preparing component A comprising one or more
methacrylate or acrylate ester monomers, and a sulfur bearing
compound, preparing component B, comprising one or more acrylate or
methacrylate ester monomers and an amine promoter or activator,
wherein either component A or component B or both further comprise
a thermoplastic block copolymer component selected from the group
consisting of a. a linear styrene-butadiene-styrene copolymer, b. a
radial styrene-butadiene-styrene block copolymer with a
plasticizer, c. a linear or radial styrene-isoprene-styrene block
copolymer, d. a linear or radial styrene-butadiene-isoprene-styrene
block copolymer, and mixtures thereof, wherein the ratio of
component A to component B is about 1:1, and mixing component A
with component B to form an adhesive composition.
19. The process of claim 18, wherein benzoyl peroxide is not used
with either component A or component B.
20. The process of claim 18 further comprising adding an adhesion
promoter to component A or B or both.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims priority from Provisional
Application No. 60/752,713, filed on Dec. 21, 2005.
FIELD OF INVENTION
[0002] This invention relates to liquid and paste compositions
comprising mixtures of polymers and acrylic or methacrylate
monomers that are hardened by free radical polymerization to form
high strength, flexibilized materials. The hardened compositions
are generally useful as adhesives, filling and repair materials,
coatings and the like.
BACKGROUND OF THE INVENTION
[0003] Commercial and prior art methacrylate adhesive compositions
capable of being mixed in a 1:1 ratio and also having practical
storage life or shelf life heretofore have not been as elastic or
ductile as adhesives with the common but less practical 10:1 mix
ratio. This is especially evident upon aging of the adhesive over
time or at elevated temperatures. The latter compositions generally
employ benzoyl peroxide as the primary initiating species. The
earliest and most widely used catalyst combination comprises
benzoyl peroxide and a tertiary aromatic amine. The amine is
generally incorporated in the polymer and monomer mixture, and the
benzoyl peroxide is supplied separately and added to the monomer
composition at the time of use. The mixing ratio of monomer
composition to peroxide is typically from about 100:1, if pure BPO
is used, to about 10:1 or less, if it is diluted with a plasticizer
for more convenient mixing. The minimum practical ratio of monomer
composition to peroxide component is about 4:1, because the inert
plasticizer and other ingredients in the peroxide component have a
negative effect on the properties of the cured composition. Benzoyl
peroxide is not stable when mixed with methacrylate monomers.
Stability of the peroxide catalyst species in admixtures with
methacrylate mixtures is necessary for safe and practical storage
prior to use in typical 1:1 mix ratio formulations. For this
reason, benzoyl peroxide is not a catalyst component in the
preferred embodiments of the inventive compositions.
[0004] Commercial and prior art methacrylate adhesives with a 1:1
mix ratio typically employ an initiator system comprising a
sulfonyl chloride initiating species, a hydroperoxide or other
stable non-BPO co-initiating species, and an amine-aldehyde
activator. The initiating species are included in the adhesive
portion or component A of the adhesive, and the aldehyde-amine
activator is included in the activator portion or component B of
the adhesive. A common source of sulfonyl chloride is
chlorosulfonated polyethylene, sold commercially as Hypalon by
dupont. A preferred aldehyde-amine activator is Reillcat ASY-2, a
reaction product of butyraldehyde and aniline that is enriched in
the content of the active dihydropyridine component, generically
referred to as DHP.
[0005] While the hydroperoxide/sulfonyl chloride/DHP curing system
has provided a means of producing adhesives with a convenient and
non-critical 1:1 mix ratio, the resulting formulations have not
been preferred for the most demanding structural adhesives
applications. This is because these formulations are typically more
rigid and may become brittle upon aging relative to compositions
cured with BPO and tertiary amines. Therefore, there is a
recognized need for adhesives with a convenient 1:1 mix ratio and a
high degree of flexibility and retained flexibility after aging. It
has now been discovered that specific block copolymers of styrene,
butadiene and isoprene can be used to formulate adhesive
compositions with these desired characteristics using components
that provide a convenient 1:1 mix ratio. Further, in preferred
embodiments, these compositions can be formulated without the use
of benzoyl peroxide.
[0006] U.S. Pat. No. 4,574,142 to Charnock discloses toughened
two-part acrylic monomer based adhesive compositions that employ
styrene-butadiene (SBS) block copolymer rubbers. Only block
copolymers of styrene and butadiene are disclosed, and no
preference for the relative ratios of butadiene or styrene, or
structure of the polymer is disclosed. An aldehyde-amine component
is used as part of the curing catalyst system. However, it is
specified that the compositions include a free-radical catalyst
system that is free from organic sulfonyl chloride. Sulfonyl
chlorides and polymers containing sulfonyl chlorides, such as
chlorosulfonated polyethylene, which are preferred accelerators for
prior art adhesives, are specifically excluded from the
compositions. Polychloroprene, another chlorinated polymer used in
prior art compositions, is also disclosed, which has undesirable
effects. Thus, Charnock either excludes or teaches away from any
chlorine bearing species in the compositions, especially sulfonyl
chlorides.
[0007] U.S. Pat. No. 5,206,288 discloses improvements in low
temperature flexible bond properties with compositions that combine
elastomers with low glass transition temperatures Tg and core-shell
impact modifiers. In one embodiment employing Kraton in a
formulation mixed in an approximately 1:1 mix ratio, the catalyst
system comprises BPO paste as an additive in one polymer in monomer
component and a tertiary amine, N,N-dimethyl-p-toluidine in the
other. BPO is not a preferred component of the compositions of the
preferred embodiments.
[0008] U.S. Pat. No. 6,989,416 discloses methacrylate adhesives
with improved flexibility based on block copolymers of styrene and
butadiene. The adhesives contain peroxides and tertiary amine
initiators but do not contain sulfonyl chlorides or any other
sulfur bearing components or DHP components. Further, they
preferably utilize benzoyl peroxide paste as the catalyst component
in a mix ratio of 10:1.
SUMMARY OF PREFERRED EMBODIMENTS OF THE INVENTION
[0009] Preferred embodiments of this invention provide two-part
structural adhesive compositions that exhibit improved elasticity
and retention of elasticity. The adhesive compositions are mixtures
of acrylate or methacrylate monomers and polymers that comprise
[0010] A. one or more acrylate or methacrylate ester monomers,
[0011] B. a sulfur bearing compound, preferably a sulfonyl
chloride, [0012] C. an amine promoter, preferably an amine aldehyde
reaction product, [0013] D. a thermoplastic block copolymer
component selected from a group consisting of [0014] a. a linear
styrene-butadiene-styrene copolymer [0015] b. a radial
styrene-butadiene-styrene block copolymer plus a plasticizer [0016]
c. a linear or radial styrene-isoprene-styrene block copolymer, and
[0017] d. a linear or radial styrene-butadiene-isoprene-styrene
block copolymer, and [0018] E. optionally, an adhesion promoting
polymer, preferably a chlorinated polymer.
[0019] The compositions are particularly well suited for
formulation as ambient temperature curing adhesives with a
convenient 1:1 mix ratio. While it is not required for the
compositions to be mixed in a 1:1 mix ratio to benefit from the
advantages of this invention, this is a highly preferred and
practical feature for commercial products. Further, these
embodiments do not require the presence of benzoyl peroxide.
DETAILED DESCRIPTION OF THE INVENTION
[0020] It has now been discovered that an important element useful
for improved and permanent elasticity in formulations capable of
more convenient 1:1 ratio mixing is a thermoplastic block copolymer
component utilized in combination with certain free radical
initiation systems. Preferred thermoplastic block copolymer
components are selected from a group consisting of [0021] a. a
linear styrene-butadiene-styrene copolymer with a styrene content
from about 20 percent to about 45 percent [0022] b. a radial
styrene-butadiene-styrene block copolymer with a styrene content
from about 20 percent to about 45 percent plus a plasticizer [0023]
c. a linear or radial styrene-isoprene-styrene block copolymer with
a styrene content from about 10 percent to about 45 percent, and
[0024] d. a linear or radial styrene-butadiene-isoprene-styrene
block copolymer with a styrene content from about 10 percent to
about 45 percent.
[0025] Examples of acceptable thermoplastic block copolymers are
sold commercially by Kraton Polymers, Inc. under the Kratonm.TM.
trade name, by Dexco Polymers under the trade name Vectorm.TM., and
by others. The preferred free radical initiation systems include
sulfur bearing compounds, preferably sulfonyl chlorides or
sulfimides, combined with a dihydropyridine.
[0026] When the inventive compositions are formulated as adhesives,
an adhesion promoting polymer is preferably used to improve the
bond strength of the cured compositions on a variety of plastic,
metallic ceramic, wood or other materials or combinations of
materials. The choice of adhesion promoting polymers depends upon
the nature of the materials to be bonded and the required physical
properties of the cured adhesive composition.
[0027] Preferred adhesion promoting polymers are thermoplastic
resins and elastomers that are soluble or dispersible in the
methacrylate monomers. Preferred polymers for this purpose are
disclosed in U.S. Patent No. 4,182,644, which is incorporated
herein by reference. More preferred adhesion-promoting polymers are
chlorinated polymers, and most preferred polymers are chlorinated
elastomers, including chlorosulfonated polyethylene, chlorinated
polyethylene, and polychloroprene polymers. Mixtures of any or all
of the preferred polymers may be employed to advantage.
[0028] Other polymers that may be used to advantage in the
inventive formulations are impact modifiers, preferably core-shell
impact modifiers. In addition to providing improved adhesion to
some materials, this class of polymers can provide additional
benefits of Theological or handling properties and further
improvements in the ductility or toughness of the cured
compositions. The benefits of impact modifiers and in particular
core-shell impact modifiers are disclosed in U.S. Pat. No.
4,536,546, which is incorporated herein by reference.
[0029] The acrylate and methacrylate monomers used in preferred
embodiments of the inventive formulations are well known to those
skilled in the art and disclosed in the '644 patent cited above.
Most preferred monomers are methyl methacrylate monomer and higher
molecular weight monomers wherein the alcohol portion of the
monomer is based on a C.sub.6 or higher hydrocarbon moiety. A most
preferred monomer of the latter type is lauryl methacrylate.
Non-methacrylate unsaturated or vinyl monomers such as styrene,
vinyl toluene, alpha-methyl styrene, and others may be used as
necessary to provide specific benefits such as control of cure
rate.
[0030] The initiating species of a preferred embodiment of the
inventive compositions include sulfur bearing compounds and
peroxides. The activators of a preferred embodiment of the
invention include tertiary aromatic amines, amine-aldehyde
activators and active metallic species. Preferred sulfur bearing
compounds include sulfonyl chlorides or chlorosulfonated polymers,
such as chlorosulfonated polyethylene, and sulfimides, including
benzoic sulfimide or saccharin. Preferred peroxides include
hydroperoxides, such as cumene hydroperoxide and methyl ethyl
ketone peroxide, benzoate esters including t-butyl perbenzoate, and
other peroxidic species well known to those in the art. Benzoyl
peroxide is not preferred.
[0031] Preferred activators are adducts of butyraldehyde and
aniline, including products that are enriched in the active
dihydropyridine (DHP) component sold commercially as Reillcat
ASY-2. The compositions may also contain an organometallic species
capable of increasing the reactivity and cure speed of the
adhesive. Preferred active metallic species are transition metal
compounds, most preferably derivatives of long chain carboxylic
acids such as copper naphthenate copper octoate, or similar
organometallic compounds familiar to those skilled in the art.
[0032] An important feature of the preferred embodiments of this
invention is the provision of compositions that when fully cured
exhibit exceptional improvements in mechanical properties over
prior art compositions that are capable of formulation as 1:1 mix
ratio adhesive products. When tested for bulk mechanical properties
according to ASTM method D638, fully cured methacrylate adhesive
compositions of the prior art display a broad and mixed range of
thermoplastic, viscoelastic and elastic behaviors. These phenomena
are described in US Patent Application Publication US 2005/0004303
A1, which is incorporated herein by reference. For the purpose of
this discussion, the significant improvements in the preferred
compositions of the preferred embodiments of this invention consist
of a combination of high tensile strength and elongation at
failure, coupled with a high degree of linear elasticity,
recoverable deformation prior to yielding, and preferably
significant strain hardening prior to failure. From the engineering
standpoint, these are highly desirable features for a structural
adhesive.
[0033] In addition to the polymeric components cited above, any
number of additional components that are well known to those
skilled in the art may be used to formulate the adhesive
compositions of the preferred embodiments of this invention. These
include non-polymeric adhesion promoters, such as polymerizable
carboxylic acids and acrylated or methacrylated phosphate esters,
corrosion inhibitors, including zinc and molybdate compounds, epoxy
resins, fillers, plasticizers, vapor barrier waxes and the like.
They may also include polyester resins and acetylenic alcohols.
[0034] Preferred compositions comprise (A) about 20 percent to
about 90 percent of a methacrylate monomer, (B) about 0.02 to about
30 percent of a sulfur bearing compound or a chlorosulfonated
polymer, (C) about 0.05 percent to about 10 percent of an amine
promoter, preferably a dihydropyridine, and (D) about 5 percent to
about 50 percent of a thermoplastic block copolymer component.
Additional promoters may be added as needed, particularly adhesion
promoters. The use of benzoyl peroxide is not preferred.
[0035] The preferred embodiments can be further understood from a
review of the following examples. However, the Examples are not
intended to limit the scope of the invention in any way.
EXPERIMENTAL PROCEDURES PREPARATION OF THE METHACRYLATE
SOLUTIONS
[0036] Stock solutions of thermoplastic block copolymers are
prepared in one gallon glass jars by using a jar roller to dissolve
sufficient quantities of polymer in methyl methacrylate to provide
solutions with concentrations ranging from about 30-45%. For
individual examples, the final viscosity is adjusted by adding
additional MMA after additional formulating ingredients are added.
Just prior to making the test specimens, the DHP component or BPO
component is added as the final additive to initiate the
polymerization.
PREPARATION OF THE TEST SPECIMENS
[0037] Bulk stress-strain properties of the adhesives are measured
according to ASTM test method D638. Test specimens are prepared by
mixing a sufficient quantity of adhesive to prepare a uniformly
flat film of adhesive approximately 6 to 7 inches in diameter and
approximately 0.125 inches thick. The adhesive components are
combined in the specified ratios by simple hand mixing in a beaker.
After the adhesive is thoroughly mixed, the beaker is placed in a
vacuum chamber and vacuum is applied intermittently to remove air
until the last one or two applications of vacuum does not produce
additional frothing or expansion. The adhesive is then transferred
to one of two glass or plastic plates approximately 12 inches in
diameter with a similar sized layer of Mylar release film on top of
it. The adhesive is placed in the center of the film, and a mating
Mylar film and plate are placed over the adhesive and pressed down
uniformly to spread the film. Metal shims are placed around the
perimeter of the plates to establish the desired film
thickness.
[0038] After the films are cured, the plates are removed. Test
dumbbells are cut from the films as specified in the test method,
taking care to cut the specimens from the most void-free section of
the film. The films are allowed to cure overnight at ambient
temperature followed by a thermal postcure at 82.degree. C. for one
hour prior to cutting the dumbbells. Each test number is the
average of five individual test specimens.
[0039] Examples 1-5 compare preferred formulations (2-4) with a
prior art formulation (5). Comparison of examples 1 and 2
illustrates the effect of added plasticizer to provide the desired
properties when the thermoplastic block copolymer is a radial SBS
block copolymer. TABLE-US-00001 EXAMPLES 1 2 3 4 5 Component MMA
Monomer 63.81 53.85 58.50 59.25 61.50 Methacrylic Acid 5.00 5.00
5.00 5.00 5.00 Kraton D 1116 27.35 27.40 Kraton D 1101 31.50 Kraton
D 1111 31.90 33.00 DOP 10.00 p-TSCl 3.00 3.00 3.00 3.00 CHP 0.75
0.75 0.50 0.75 DHP 2.50 2.50 2.40 2.50 HET 0.5 CuAcAc Soln 0.10
0.10 0.10 0.10 Benox B55 2.5 Tensile Properties ASTM D638 after
82.degree. C./1 hr postcure Tensile stress (psi) 1190 905 1545 1295
1467 Elongation, % 91.8 407 342 534 100 Strain harden Y/N No Yes
Yes Yes No Block Copolymer Type SBS SBS SBS SIS SIS Linear/Radial
Radial Radial Linear Linear Linear Plasticizer Y/N No Yes No No No
Other Components MMA Monomer Methyl methacrylate monomer Lucite
Kraton Polymers Thermoplastic block copolymer Kraton DOP
Dioctylphthalate plasticizer Aldrich p-TSCl p-Toluenesulfonyl
chloride Aldrich CHP Cumene Hydroperoxide Hercules DHP Enriched
dihydropyridine (DHP) Reilly Industries HET N,N-bis Hydroxyethyl
Toluidine Bayer CuAcAc' solution 0.5% solution of copper acetyl
Laboratory Acetonate in MMA monomer Prep/Aldrich Benox B55 55%
Benzoyl peroxide/benzoate Norac Plasticizer
Particularly preferred compositions are shown in Examples 2, 3 and
4.
* * * * *