Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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"ADDITIVE FOR TWO COMPONENT EPOXY RESIN COMPOSITIONS"
BACKGROUND OF THE INVENTION
l. Field of the Invention
This invention relates to novel additives for two
component epoxy resin compositions. The invention also
extends to a method of filling cracks or ~oints in
concrete with the two component epoxy resin.
2. Description of Related Art
Epoxy resin compositions are well known. They contain
the reactive oxirane ring structure:
0
- CH - CH -
commonly called epoxy. Liquid epoxy resins are commonly
converted, through reaction at the reactive epoxy sites
into tough, insoluble and infusible solids having wide
applications. The liquid epoxy resin is typically
provided as part of a two component system, component A
containing the liquid epoxy resin, hereinafter termed the
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resin component, and component B containing the liquid
hardener or curing agent, hereinafter termed the hardener
component. When mixed together, these components form a
pasty resin composition which cures to a flexible or
inflexible solid, depending on the particular resin,
curing agent and additives employed.
Of the known liquid epoxy resins the most common
include those prepared by the condensation of a lower
alkylidene-diphenol such as bisphenol A, with an
epihalohydrin such as epichlorohydrin in conjunction with
sodium hydroxide to form a bis (epoxyloweralkoxyphenol)
lower alkane or derivative thereof. Lower as used herein
throughout the disclosure and claims with alkoxy or alkane
or alkylidene refers to Cl 4 units. The most common
epoxy resin useful in this invention is that formed from
bisphenol A and epichlorohydrin to form 2, 2 - bis [4 -
(2' 3' epoxypropoxy) phenyl] propane, also termed a
diglycidyl ether of bisphenol A, which has a typical
molecular weight of about 400 daltons. Higher molecular
weight homologs of these resins which introduce further
reactive sites with additional hydroxyl groups are well
known.
Epoxy resins of the type just discussed with molecular
weights of about lOOO daltons or greater generally have
high viscosities and high solids contents, both of which
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can limit applications for their use. Use of such resins
as sealants is limited because of high viscosities. The
term sealant as used herein refers to a resin with utility
to fill cracks or joints in a cementitious substrate.
Additives have heretofor been suggested for inclusion
in the manufacture of epoxy resins in order to lower the
resin viscosity. U.S. Patent 2,901,462 issued August 25,
1959 to Anderson et al, and U.S. Patent 3,145,191 issued
August 18, 1964 to Perfetti are exemplary. However, such
additives are incorporated during the condensation
reaction complicating the manufacture of the epoxy resin
itself. It is also known to add solvents such as methyl
ethyl ketone or xylene to an epoxy resin to lower the
resin viscosity. While the inclusion of the solvent might
improve penetration of the resin through the lowered
viscosity, the cured resin composition includes voids due
to evaporation of the solvent. In fact, none of the above
solutions, to the inventors' knowledge, provides an epoxy
resin composition which can penetrate into cracks or
joints in a substrate such as concrete, particularly when
the cracks are very fine and deep, while also being able
to adhere and cure below the surface and within these deep
cracks.
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There is a particular need for a crack sealant
having good penetration and adherence qualities for
concrete substrates. In past years, corrosion to the
steel reinforcements in concrete from salt applied to melt
winter ice has become a major problem. A sealant for
concrete which will penetrate into joints and cracks to
limit or prevent such corrosion is desired.
SUMMARY OF THE INVENTION
Unless indicated otherwise, all numbers expressing
quantities of ingredients or reaction conditions are to be
understood as modified by the term "about". All
quantities of ingredients, unless indicated otherwise are
understood to be percentage weight.
In one aspect of the invention, a method of filling
cracks in cementitious substrates comprises applying to
the area to be filled a composition comprised of a resin
and a hardener. The resin component comprises: (a) from
about 50% to about 99% by weight of a liquid epoxy resin
having a molecular weight of from about 400 to about 1000
daltons which is the product of the reaction of Cl_4
alkylidene-diphenol and an epihalohydrin; (b) from O to
about 20% by weight of a mono, di, or trifunctional
glycidyl ether which is the reaction product of an
aliphatic or aromatic polyether and an epihalohydrin; (c)
from 0 to about 30% by weight of a polyglycol diepoxide;
and (d) from about 1 to about 10% by weight of a
polyhydroxy compound selected from the group consisting of
glycerine, ethylene glycol, diethylene glycol, and
triethylene glycol. The hardener component comprises:
(a) from about 60 to about 98% by weight of a curing agent
~ ,. .
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-- 5 --
having functional groups capable of effecting crosslinking
of the oxirane groups present in said epoxy resin; (b)
from 0 to about 30% by weight of an accelerator; and (c)
from about 2 to about 10% by weight of a trialkylsilane.
In the method, the weight ratio of resin component A) to
hardener component B) is from about 2:1 to about 4:1.
In particular aspects of the method, in component
A)(b) the glycidyl ether is a C12_14 alkyl glycidyl
ether. Also, in a further aspect of the invention, the
component B also contains from about 0.1 to about 0.5% by
weight of a water scavenger.
In a further aspect of the invention a method of
filling cracks or joints in cementitious substrates
comprising applying to the cracks or joints to be filled
an epoxy resin composition comprising components A and B.
The component A comprises a resin component containing
from about 50 to about 100% by weight of a liquid epoxy
resin having a molecular weight of from about 400 to about
1000 daltons which is the product of the reaction of Cl_4
alkylidene-diphenol and an epihalohydrin. It further has
from 0 to about 30% by weight of a polyglycol diepoxide,
and from 0 to about 20% by weight of a mono, di, or
trifunctional glycidyl ether which is the reaction product
of an aliphatic or aromatic polyether and an
epihalohydrin. Component B comprises a hardener component
containing from about 60 to about 98% by weight of a
curing agent having functional groups capable of effecting
crosslinking of the oxirane groups present in said epoxy
resin, from 0 to about 30% by weight of an accelerator,
and from about 2 to about 10% by weight of a
trialkylsilane. Component C comprises from about 1 to
about 10% by weight, based on the weight of said epoxy
.
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- 5a -
resin composition of a polyhydroxy compound selected from
the group consisting of glycerine, ethylene glycol,
diethylene glycol, and triethylene glycol. The weight
ratio of component A to component B is from about 2:1 to
about 4:1.
The term glycol additive, as used herein, is meant
to include glycerine even though, strictly speaking, the
term glycol is commonly used in the art to refer only to
dihydric alcohols.
In general, the glycol additive of this invention
can be incorporated into either or both of the resin or
hardener components. However, as will be mentioned
hereinafter, when the epoxy resin composition is intended
as a sealant for concrete, a silane additive may be
included in either the resin or hardener component to
improve adhesion to damp concrete. Since the glycol
additive can react with silane, the glycol additive in
such instances is preferably included in the component
which does not contain the silane additive.
The preferred epoxy resins are the diglycidyl
ethers of bisphenol A or bisphenol F resulting from
reaction of bisphenol A or bisphenol F with
epichlorohydrin. Most preferably, the resin includes a
reactive diluent selected from the group consisting of
mono, di or tri-functional glycidyl ethers which reduces
the viscosity of the liquid epoxy resin. Generally, with
such resins, the glycol additive provides excellent
penetration and adherence when included in an amount of
about 1 to 10 weight percent. The most preferred glycol
additive is glycerine.
Q
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Preferred curing agents are those of the
polyamine-type generally known in the art. These include
aliphatic (including cyclo-aliphatic) primary or secondary
amines, alcohol amines, polyalkylene amines, aromatic
amines, polyether amines, polyamides, amido amines and
mixtures of these amines.
Other additives preferably included with the curing
agent in the hardener component are one or more
accelerators, for example C7 12-alkylphenols and/or,
bisphenol A, and water scavengers, for example MgO. While
not being bound by the same, it is believed that the
hydroxyl groups present on the accelerator further improve
the ability of the epoxy resin composition to adhere in
substrate cracks or joints. Preferably, the curing agent
will constitute 70-100% wt, the accelerator and bisphenol
A combined 0-30% wt and the water scavenger 0-0.5 wt. If
a silane additive is included, it is preferably included
in an amount of about 2-10% wt. In the event that the
glycol additive is included in the hardener, it is
included in an amount sufficient to provide an amount of
about 1 to 10% wt in the final epoxy resin composition,
and the silane additive is omitted, or is included in the
resin component.
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The invention also extends to a method of filling
cracks or joints in concrete, comprising applying to the
area to be filled, a two component epoxy resin composition
containing the above-mentioned liquid epoxy resin and
curing agent in admixture, wherein one or both of the
resin or hardener components includes the glycol additive
of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
An epoxy resin composition of this invention
preferably includes the following ingredients in the
amounts indicated:
A) Resin Component:
i) Liquid epoxy resin - 50-99% wt; most preferably
60-80% wt;
ii) Reactive diluent - 0-20% wt, most preferably
10-20% wt;
iii) Modifier - 0-30% wt, most preferably
10-30% wt; and
iv) Glycol Additive - l-10% wt, most preferably
3-8~ wt.
B) Hardener Component:
i) Curing Agent - 60-100~ wt, most preferably
70-90% wt;
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ii) Accelerators- 0-30~ wt, most preferably
C7_12~alkYl phenols-
4-10% wt and bisphenolA-
10-20~ wt;
iii) Silane Additive- 0-10% wt, most preferably
2-7~ wt; and
iv) Water Scavenger- 0-0.5% wt, most preferably
0.1-0.5~ wt.
In the event that the glycol additive is included in
the hardener component, the silane additive is omitted and
the glycol additive is included in an amount to provide
about 1 - 10~ wt in the final epoxy resin composition, the
other ingredient amounts being adjusted accordingly.
Typically, the glycol additive will comprise about 10-30
wt of the hardener component.
The ratio of resin component to hardener component
will vary according to the particular ingredients
employed, however it will typically be between about 2:1
and 4:1.
Due to commercial availability, the most preferred
liquid epoxy resins are diglycidyl ethers of bisphenol A
or bisphenol F resulting from the condensation of
bisphenol A or bisphenol F with epichlorohydrin.
Exemplary bisphenol A and bisphenol F resins are available
from The Dow Chemical Company under the trade marks D.E.R.
331 and D.E.R. 351 and 352.
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g
To lower the viscosity of the liquid epoxy resin, a
reactive diluent is preferably included in the liquid
epoxy resin. These reactive diluents are known in the art
and resins are commercially available which incorporate
these diluents. In general, these reactive diluents are
mono, di or tri-functional glycidyl ethers, for example
prepared by condensing an epihalohydrin with various
aliphatic and aromatic polyethers. A large number of
these reactive diluents are available from Wilmington
Chemical Coporation under the trade mark Heloxy.
Exemplary are WC-7 - a C8 1O-alkyl glycidyl ether; WC-8
- a C12 14-alkyl glycidyl ether; WC-9 - a C12 13-alkyl
glycidyl ether; WC-61 - a butyl glycidyl ether; WC-62 - a
cresyl glycidyl ether; WC-63 - a phenyl glycidyl ether;
WC-64 - a nonylphenyl glycidyl ether; WC-65 - a
p-tert-butyl-phenyl glycidyl ether; MK-116 - a
2-ethylhexyl glycidyl ether; WC-67 - a diglycidyl ether of
1,4-butanediol; WC-68 a diglycidyl ether of neopentyl
glycol; MK-107 - a diglycidyl ether of cyclohexane
dimethanol; WC-69 - a diglycidyl ether of resorcinol;
WC-97 - a triglycidyl ether of trimethylol propane; and
WC-98 - a triglycidyl ether of trimethylol ethane.
A preferred liquid epoxy resin for use in the present
invention is available from The Dow Chemical Company under
the trade mark D.E.R. 324. This resin is of the bisphenol
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A type mentioned above, but includes about 17~ wt of the
reactive diluent WC-8, defined above.
A further preferred additive in the resin component is
a modifier of the polyglycol diepoxide resin type which,
when blended with the resin ingredients mentioned above,
imparts flexibility, elongation and improved impact
resistance. This modifier additive also serves as a
viscosity reducer. Exemplary and preferred modifier
additives are available from The Dow Chemical Company
under the trade mark D.E.R. 732 and 736.
Particularly preferred curing agents are
polyoxyalkyleneamines, for instance polyoxypropyleneamine,
aliphatic amines such as diethylenetriamine (DETA) or
triethylenetetramine (TETA), aminoalkyl piperazines such
as n-aminoethylpiperazine (~AEP ) . A number of
polyoxyalkyleneamines, particularly polyoxypropylene-
amines, are available from Texaco Chemical Company under
the trademark Jeffamine. Jeffamine D-230 is particularly
preferred and is represented by the formula:
2 1 2-~ 0CH2fH ~--XNH2, wherein x is
CH3 CH3
approximately 2.6. Also preferred is Jefferson EDR 148
(trade mark of Texaco Chemical Company), which is a
triethylene glycol diamine.
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A number of other exemplary and preferred curing
agents are available from EIenkel Corporation under the
following trade marks: Genamid 151 or 601CE - amido
amines, Versamid 115 or 115CE - polyamides, Versamine C31
or 671CE - cycloaliphatic polyamines, and Versamine 908 or
640CE - aliphatic polyamines.
While any of the above curing agents may be used
alone, most preferably, the hardener component includes a
mixture of curing agents. One particularly preferred
combination which has been found to be useful when the
epoxy resin composition is used with concrete, includes a
polyoxypropylene amine, DETA, TETA, NAEP and an amido
amine such as Genamid 151.
To improve adherence to concrete surfaces,
particularly wet or damp concrete surfaces, the epoxy
resin composition of this invention preferably includes a
silane additive. Silane additives for this purpose are
known in the art for inclusion in either the resin
component or the hardener component. Exemplary of a
silane additive for inclusion in the hardener component is
Silane A-1120 available from Union Carbide. Exemplary of
silane additives for inclusion in the resin component are
r-methacryloxypropyl trimethoxy silane, ~-(3,4-epoxycyclo-
hexylethyl trimethoxy silane and ~-glycidoxypropyl tri-
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methoxy silane.
Water scavenger agents such as magnesium oxide may be
included in the hardener or resin components to prevent
the silane from reacting with itself. In general, the
water scavenger is not needed if other ingredients in the
epoxy resin composition are dry.
As is common in two component epoxy resins, one or
more accelerators are preferably included in the hardener
component to decrease the cure time for the mixed
composition. Such accelerators function as catalysts in
the cross-linking reaction. Exemplary and preferred are
alcoholic or phenolic hydroxyl-containing compounds, for
instance, C7-C12 alkyl phenols. Particularly
preferred are nonyl phenol and bisphenol A. Without being
bound by the same, it is believed that the hydroxyl groups
of the accelerator cooperate with the glycol additive of
this invention to improve the adherence of the composition
in cracks and joints in a substrate such as concrete.
The invention is further illustrated by the following
non-limiting examples.
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Example 1
To demonstrate that epoxy resin compositions according
to the present invention are capable of both penetrating
and adhering in deep concrete cracks, four resin
compositions set forth below were formulated and applied
to 4" X 4" concrete cubes which had been cracked, with
cracks varying in size between 20 thousands of an inch
(thou) at the top to 6 thou at the bottom. The sides and
bottom portion were sealed with wax and a small reservoir
was created at the top. The resins were mixed with a red
dye and ponded at the top of the crack.
Resin 1
Resin Component - Dow D.E.R. 324100% wt
Hardener Component -
(a) Hardener 1432-B, detailed below44% wt
NAEP 7.97% wt
TETA 15.46% wt
DETA 7.97% wt
Genamid 151 22.20% wt
Jeffamine D-23025.19% wt
Bisphenol A 16.70% wt
Nonyl Phe~ol4 . 5196 wt
(b) Jeffamine D-230 44% wt
(c) Glycerine 12~ wt
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The 1432-B hardener was prepared by mixing and heating
together the aliphatic and amido amines to 120~C, adding
bisphenol A, then cooling and adding the nonyl phenol and
Jeffamine D-230.
Ingredients (a) (b) and (c) of the hardener were mixed
together in the amounts indicated.
The resin and hardener components were mixed in a ratio of
78:22 by weight and the gel time for 200 g at 25C was 70
min.
Resin 2
Resin Component - Dow D.E.R. 324 10096 wt
Hardener Component - NAEP 10096 wt
The components were mixed in a ratio of 82:18 by weight
and the gel time for 200 g at 25C was 24 min.
Resin 3
This resin was prepared as Resin 1, but without the
glycerine additive. The components were mixed in a ratio
of 80:20 by weight and the gel time for 200 g at 25C was
85 min.
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Resin 4
This resin was prepared as Resin 2 with 12% wt of
glycerine being added to the NAEP curing agent. The
components were mixed in a ratio of 80:20 and the gel time
for 200 g at 25C was 22 min.
After the resins had cured, 3" cores were removed from
the blocks and examined. Resin 1 totally filled the core
and all small air voids adjacent the cracks. This resin
composition had totally filled the cracks rather than
simply draining through the block, demonstrating the
ability of this composition, with the glycerine additive
to both penetrate and adhere in deep cracks. Resin 3,
which was Resin 1 without the glycerine additive, showed,
on examination of the core that, although the resin
composition would penetrate into the cracks, a major
amount drained from the cracks without adhering in and
filling the crack. Only about 60% of the cracks were
filled. Resin 4 gave results similar to Resin 1, with
about 70% filling of the cracks. Resin 1, which included
the more preferred mixture of curing agents and
accelerators, was superior to Resin 4 in adhering in the
cracks. Resin 2, which was Resin 4 without the glycerine
additive, quickly drained from the cracks in the core
leaving the top two thirds of the cracks containing
virtually no resin, with only about 30% filling of the
cracks.
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These results demonstrate that, without the glycol
additive of this invention, the epoxy resin composition
will penetrate but will not adhere in and fill cracks in
the concrete.
Examination of the cores filled with Resin 1 showed
penetration and adherence into cracks as wide as 16 - 20
thou and as small as 2 thou. Air voids as large as 60
thou were also filled by Resin 1.
Screening tests conducted in accordance with the
procedure set out in Example 2 suggest that an epoxy resin
composition similar to Resin 1, but which eliminates the
additional Jeffamine D230 (ingredient (b) set forth above)
from the hardener component, provides even better ability
to adhere in and fill concrete cracks and joints.
Example 2
A screening test was developed to approximate a
concrete substrate and test the ability of a resin
composition to both penetrate and adhere to that
substrate. The test consisted of pouring 15g of the epoxy
resin composition to be tested onto an uncured mixture of
a cementitious mixture comprising 1 part masonry cement
and 2 parts sand (sieve analysis as follows with
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percent passing of #4 - 100~, #8 - 100%, #16 - 95-100%,
#30 - 90-100%, #50 - 40-60~, #100 - 5-10%, and #200 -
0-2%). The weight of the mixture picked up by the resin
after a cure time of 24 hrs at ambient temperature was
determined. While resins which picked up a large quantity
of the mixture demonstrate good penetration abilities, the
higher weight values demonstrate that such resins do not
adhere well and are unlikely to fill a concrete crack.
In accordance with this screening test, the glycol
additives of the present invention were tested. The resin
and hardener components were mixed in a weight ratio of
80:20 when the hardener was 1432B (as set forth in Example
1) and in the ratio of 82:18 when the hardener was N~EP.
~le glycol additive was included, as indicated, in an
amount to provide 3% wt in the final epoxy resin
composition. The hardener 1432B was prepared as set out
in the Example 1.
. Resin Elardener Wt of Mixture (g)
~ow D.E.R. 324 N~EP (Control) 53.3 (average)
Dow D.E.R. 324 N~EP + Glycerine 37.3
Dow D.E.R. 324 N~EP ~ Ethylene Glycol 36.4
Dow D.E.R. 324 N~EP + Diethylene Glycol 39.3
Dow ~.E.R. 324 N~EP + Triethylene Glycol 40.9
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B. Resin Hardener Wt of Mixture (g)
Dow D.E.R. 324 1432B (Control) 39.3
Dow D.E.R. 324 1432B + Glycerine 31.6
Dow D.E.R. 324 1432B + Ethylene Glycol 35.1
Dow D.E.R. 324 1432B + Diethylene Glycol 38.6
Dow D.E.R. 324 1432B + Triethylene Glycol 36.3
The above data shows that the glycol additive improves
the ability of the resin composition to adhere to the
substrate as evidenced by the reduction in the weight
values. The effect of the glycol additives in the
screening test is most pronounced with the NAEP hardener,
which is less preferred than the 1432B hardener defined in
the previous example. In general, glycerine is the most
preferred of the glycol additives.
Example 3
The screening test set forth in Example 2 was repeated
with resin compositions incorporating a modifier of the
polyglycol diepoxide resin type in the resin component.
The particular modifier used was Dow D.E.R. 736, which was
mixed in a weight ratio of 25:75 with the resin Dow D.E.R.
324. The glycol additives were included in the hardener
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component in an amount sufficient to provide 3% wt of the
total epoxy resin composition. The resin and hardener
components were mixed in a weight ratio of 80:20. The
weight values are set forth below.
A. Resin Hardener Wt of Mixture (g)
D.E.R. 324/D.E.R. 736 1432B (Control) 54.9
D.E.R. 324/D.E.R. 736 1432B + Glycerine 39.5
D.E.R. 324/D.E.R. 736 1432B ~ Ethylene Glycol 50.2
D.E.R. 324/D.E.R. 736 1432B + Triethylene Glycol 52.8
Here again, the reduction in weight values shows the
improvement in the ability of the resin toadhere to a
substrate approximating concrete when the resin
composition includes the glycol additive.
It is to be understood that the above-described
embodiments of the invention are illustrative only and
that modifications will be evident to persons skilled in
the art.
