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Description  |
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This invention relates to a novel asphalt composition and more particularly
to an asphalt composition characterized in that it contains an epoxy
resin, a maleinated asphaltic material or its esters, and a necessary
amount of a curing agent for epoxy resins.
Because of a high demand for a better quality material for pavement of
roads, airfields and others there have so far been made various attempts
to produce such materials. As examples of such products, there have been
known a mixture of an epoxy resin and coal tar and a mixture of an epoxy
resin and asphalt. But the former mixture has the defects that its aging
resistance after curing is not sufficient and that it becomes brittle in
cold weather because of the comparatively high temperature at which it
becomes brittle. Besides, it is known that its component coal tar contains
a large amount of a carcinogenic substance benzo(a)pyrene. The latter
mixture, on the other hand, has the defects that the epoxy resin and the
asphalt tend to separate from each other due to their poor compatibility
with each other and that the curing of the mixture is difficult to effect
even with the addition of a curing agent to it and in some cases only the
resin is cured without forming the cured composition of uniform quality.
There have also been known a process for modifying asphalt with maleic
anhydride or the like and a process for modifying a mixture of asphalt and
rubber with maleic anhydride or the like. The products obtained by these
known processes have insufficient hardness and they will exhibit
undesirable phenomena such as rutting if they are used in road pavement.
An object of this invention is to provide a uniform and satisfactorily hard
asphalt composition containing little or no carcinogenic substance, which
is produced not using coal tar or the like but using a reformed asphaltic
material excellently compatible with epoxy resins.
The asphalt composition of this invention is characterized in that it
comprises (A) 100 parts by weight of an epoxy resin, (B) 10-1,000 parts by
weight of maleinated asphaltic material or an ester of a maleinated
asphaltic material, and, if desired, (C) a curing agent for epoxy resins.
Japanese Patent Gazette No. 3288/63 discloses a process for reacting an
adduct of maleic anhydride to asphalt with a polyhydric alcohol to produce
a polyester and then reacting the hydroxyl groups in the thus produced
polyester with a fatty acid or abietic acid for esterification. In
contrast, the maleinated asphaltic material according to the present
invention is not esterified with a fatty acid or abietic acid in the
practice of the present invention. Japanese Patent Application Laying-Open
Gazette No. 157415/75 discloses a composition comprising bitumen (modified
bitumen) containing carboxylic and/or acid anhydride groups and/or groups
derived from the carboxylic and/or acid anhydride groups; a polymer or
copolymer (1) containing said groups (a); and/or a polymer or copolymer
(2) containing at least two functional groups (b) other than the groups
(a). The Laying-Open Gazette discloses a reaction product of bitumen and
maleic anhydride, as an example of the modified bitumen. However, it
describes styrene-butadiene rubber derivatives as examples of the polymer
or copolymer (1) and also describes dihydroxypolybutadienes as examples of
the polymer or copolymer (2). Thus, the polymers or copolymers (1) and (2)
according to the Laying-Open Gazette are rubber-like polymers or
copolymers and do not include epoxy resins as used in the present
invention.
In addition, Japanese Patent Gazette No. 8468/63 discloses a composition
comprising an epoxy resin, primary polyamine and asphaltic material;
Japanese Patent Gazette No. 9270/64 discloses a composition comprising
coal-tar pitch, a glycidyl ether ester and a curing agent; Japanese Patent
Gazette No. 30459/70 discloses a reaction product of swollen coal and
maleic anhydride; Japanese Patent Gazette No. 21115/71 discloses an
adhesive comprising an epoxy resin, cut-back asphalt, coal tar, a curing
agent and an inorganic filler; and Japanese Patent Gazette No. 22930/76
discloses a composition comprising an epoxy resin, asphalt, tar, coal
powder and a curing agent. However, the compositions disclosed by these
Patent Gazettes are different in constitution from the asphalt composition
of the present invention.
The maleinated asphaltic material to be used may preferably be the reaction
product of an asphaltic material and maleic anhydride, and the ester of
the maleinated asphaltic material may preferably be an ester resulting
from the reaction of an alcohol with the reaction product of an asphaltic
material and maleic anhydride.
The epoxy resins usable in this invention are commonly used ones and, in
particular, compounds having a molecular weight ranging from 340 to 7,000
and at least one epoxy group
##STR1##
in the molecule.
Such epoxy resins include glycidyl ether type resins, glycidyl ester type
resins, glycidyl amine type resins, linear aliphatic epoxy resins and
alicyclic epoxy resins. These resins are described in Gekkan Kobunshi Kako
Bessatsu 9 "Epokishi Jushi (Annex 9)" "Epoxy resin" to "Working of High
Molecular Weight Material" published in June, 1973. Glycidyl ether type
resins, glycidyl ester type resins and glycidyl amine type resins may be
prepared by reacting the corresponding polyhydric alcohol(s), polybasic
acid(s) and polyamine(s) with epichlorohydrin and then
de-hydrochlorinating the reaction products.
Also usable are derivatives of these epoxy resins or their mixtures. The
most preferable epoxy resins for use in this invention is glycidyl ether
type resins, particularly glycidyl ether of bisphenol A.
The maleinated asphaltic material to be used in this invention may be
prepared, for instance, by reacting maleic anhydride with asphaltic
material.
The asphaltic material mentioned here means asphalt or petroleum tar which
is generally known for road paving application. This is to say, the word
"asphalt" means natural asphalt or petroleum asphalt. The natural asphalt
includes, for example, asphaltite such as gilsonite, grahamite and glance
pitch; lake asphalt such as trinidad asphalt; and rock asphalt. The
petroleum asphalt that may be used includes straight asphalt obtained by
distillation of a crude oil, blown asphalt produced by blowing an
oxygen-containing gas into straight asphalt in the presence or absence of
a catalyst, solvent-extracted asphalt yielded when the asphaltic material
is separated from the petroleum fraction containing it by the use of
propane or other solvents, and cutback asphalt which is a mixture of
straight asphalt and a light petroleum. The petroleum tar that may be used
includes oil gas tar obtained as a by-product when gases are produced from
petroleum fractions, such tar in refined form, cutback tar obtained by
incorporating a light petroleum fraction into such tar, and a tar pitch
which is obtained as the residue by removing the volatile fraction from
such tar. Any of these kinds of asphalt may be used singly or jointly. The
asphaltic material that may preferably be used in this invention is
asphalt. This is because coal tar is generally more sensitive to a change
of temperature than asphalt and also because the amount of benzo(a)pyrene
contained in asphalt is much smaller than that in coal tar. The most
preferable asphaltic material in this invention is straight asphalt,
particularly that having a penetration of 20-300 and a softening point of
not higher than 90.degree. C.
In this invention, in order to prepare the maleinated asphaltic material
the said starting asphaltic material and maleic anhydride may be reacted
together at a temperature between 100.degree. and 300.degree. C.,
preferably between 130.degree. and 260.degree. C. and at a pressure of at
least atmospheric pressure, preferably between atmospheric pressure and 30
kg/cm.sup.2. There is no particular need for a solvent or a catalyst but
they may be used if necessary. The blending ratio of the asphaltic
material to maleic anhydride may be selected as desired according to the
kind of the asphaltic material used and the intended use of the resulting
composition. The preferable blending ratio is in the range of from 100
parts by weight of the former to 0.2-100 parts by weight, more preferably
0.5-20 parts by weight, of the latter.
The reaction product obtained by reacting the asphaltic material with
maleic anhydride in the above-mentioned weight ratio may contain the
unreacted maleic anhydride or decomposition products of maleic anhydride.
These components so contained may be previously removed from, or left in,
the reaction product when it is used. The said reaction product may be
used singly as a binder or may be used jointly with one or more of the
above-mentioned kinds of asphaltic material.
In this invention, in order to prevent the reaction between the epoxy resin
and the maleinated asphaltic material in the presence of a curing agent
from taking place faster than is necessary for a particular purpose of
using the composition containing these reactants, the maleinated asphaltic
material may be partly or wholly replaced by its ester. Thus, it is
possible to control the reaction velocity. The esters of maleinated
asphaltic material to be used in this invention may be prepared, for
instance, by reacting the said starting asphaltic material with an ester
obtained by the reaction of maleic anhydride and an alcohol, or by
reacting an alcohol with the reaction product of the said starting
asphaltic material and maleic anhydride. Any alcohol may be used, but
those having 1-10 carbon atoms may advantageously be used. Preferable
alcohols are methanol, ethanol, isopropyl alcohol, glycol, glycerine,
benzyl alcohol and cyclohexyl alcohol, with monohydric alcohols being
particularly preferred. These reactions may take place at ambient
temperature or up to 230.degree. C., preferably at ambient temperature or
up to 200.degree. C., and at atmospheric pressure or up to 30 kg/cm.sup.2,
preferably at atmospheric pressure or up to 20 kg/cm.sup.2.
In this invention the weight ratio of the epoxy resin and the maleinated
asphaltic material or its ester used may preferably be in the range of
from 100 parts by weight of the former to 10-2,000 parts by weight, most
preferably 20-1,000 parts by weight, of the latter. If the quantity of the
latter is less than 10 parts by weight, the resulting cured composition
will be insufficient in flexibility and other properties, and if it is
more than 2,000 parts by weight, the effect of the epoxy resin contained
in the composition in this case will be unsatisfactory. The mixing of the
two components may be performed at a temperature between
0.degree.-200.degree. C., preferably between 10.degree.-160.degree. C.,
and for a period of from 5 seconds to 3 hours, preferably from 10 seconds
to 10 minutes. If the mixing temperature is lower than 0.degree. C. or if
the mixing time is less than 5 seconds, the mixing of the epoxy resin and
maleinated asphaltic material is insufficient and hardness (penetration)
of the resulting composition is not uniform at every part thereof. More
particularly, if the composition is prepared under the above-mentioned
preferable conditions, the product will be a uniform composition of the
epoxy resin and reformed asphaltic material, which product is not a mere
mixture of the two but a chemically bonded, epoxy-modified asphaltic
material.
If desired, the composition, after mixing, may be allowed to stand still
for ageing. In this case there are no specific limitations on the
conditions under which the ageing is effected. However, the ageing may be
effected at temperatures of 0.degree.-200.degree. C., preferably
10.degree.-160.degree. C., for a period of 10 minutes to 6 months,
preferably 10 minutes to 2 months.
In this invention, not more than 1,000 parts by weight of a curing agent
for epoxy resins may be further added, if necessary, to a composition of
100 parts by weight of an epoxy resin and 10-2,000 parts by weight of a
maleinated asphaltic material or its ester. The further addition of the
curing agent for epoxy resins may not be necessary. But, if necessary, it
is effected depending on the heating conditions for reacting the epoxy
resin with the maleinated asphaltic material or its ester, or depending on
properties required in the composition to be produced. The more preferable
amount of the curing agent used is, by weight, 0.1-300 parts per 100 parts
of the epoxy resin used. The curing agents for epoxy resins to be used in
this invention are generally known curing agents hitherto used on epoxy
resins, such as aliphatic polyamines, aromatic polyamines, primary, sec.-
and tert.-amines, maleic anhydride, phthalic anhydride or other acid
anhydride, polyamide resins, polysulfide resins, boron trifluoride-amine
complex and synthetic resin precondensates like phenol resins. These
curing agents are described in the previously mentioned Annex 9 "Epoxy
resin" published in June 1973.
As mentioned above, this invention makes it possible to improve the
compatibility of asphaltic materials with epoxy resins by reforming the
former and to provide compositions from which are obtained cured products
having sufficient hardness and flexibility as well as excellent
adhesiveness, solvent resistance, heat resistance and wear resistance, the
cured products being prepared by mixing and reacting the improved
asphaltic material with the epoxy resin.
In practical applications the novel composition of the present invention
has many specific advantages. For example, it will exhibit a good
adhesiveness to aggregate, cement, asphalt, wood and metals. When the
composition is used as a coating material, the surface of the resulting
coating will be resistant to such solvents as gasoline and jet fuels. When
exposed to a high temperature, the cured composition will be less liable
to soften and run out than the hitherto known compositions in cured state.
The composition of this invention is, therefore, suitable for use, for
example, in road pavement, bridge surface pavement, heavy traffic road
pavement, road pavement in a frigid region and non-skid pavement as well
as pavement of airfields, wharfs, warehouse floors, sidewalks, tennis
courts and ship decks; it is also useful as a coating material.
This invention will be better understood by the following Examples and
Comparative examples wherein all parts are by weight unless otherwise
specified.
There were produced asphalt compositions having the formulation shown in
the following Table 1. The compositions so produced were then evaluated
for their properties. The epoxy resins, asphaltic materials and curing
agents for epoxy resins used in the compositions are listed below.
Epoxy resin A: A reaction product of bisphenol A and epichlorohydrin,
having an epoxy equivalent of 210 and a viscosity of 50,000 cps
(centipoise) at 25.degree. C.
Epoxy resin B: A reaction product of bisphenol A and epichlorohydrin,
having an epoxy equivalent of 190 and a viscosity of 13,000 cps at
25.degree. C.
Epoxy resin C: A reaction product of bisphenol A and
.beta.-methylepichlorohydrin, having an epoxy equivalent of 188 and a
viscosity of 900 cps at 25.degree. C.
Maleinated asphalt D: A reaction product, obtained by reacting 90% by
weight of 150/200 straight asphalt (having a penetration of 190) with 10%
by weight of maleic anhydride at 210.degree. C. for 4 hours.
Maleinated asphalt E: A reaction product, obtained by reacting 95% by
weight of 150/200 straight asphalt (having a penetration of 190) with 5%
by weight of maleic anhydride at 185.degree. C. for 4 hours.
Maleinated asphalt ester F: A reaction product, obtained by reacting 100
parts by weight of maleinated asphalt E with 2 parts by weight of benzyl
alcohol at 200.degree. C. for 5 hours.
Maleinated asphalt G: A reaction product, obtained by reacting 95% by
weight of a bottom oil (viscosity: 467 cSt at 98.9.degree. C.) obtained
from the bottom of a distillation tower by the distillation of a crude oil
therein under reduced pressure, with 5% by weight of maleic anhydride at
200.degree. C. for 4 hours. The reaction product had a penetration of 310
(25.degree. C., 100 g, 2 seconds).
Maleinated asphalt H: A reaction product having a penetration of 300
(25.degree. C., 100 g, 2 seconds), obtained by reacting 90% by weight of a
bottom oil (viscosity: 467 cSt at 98.9.degree. C.) produced by the
distillation of a crude oil, with 10% by weight of maleic anhydride at
205.degree. C. for 4 hours.
Curing agent I: Maleic anhydride
Curing agent J: Dimethylbenzylamine
Curing agent K: Polyamide non-solvent type curing agent having an amino
value of 315 and a viscosity of 2000 cps at 25.degree. C.
EXAMPLES 1-3 AND COMPARATIVE EXAMPLES 1-3
An epoxy resin was thoroughly mixed with an asphaltic material at
130.degree. C. The resulting two-component mixture was allowed to stand
for curing at 130.degree. C. for 5 hours, allowed to cool to room
temperature and then tested for compatibility of one component with the
other. It was found that the compositions of Examples 1, 2 and 3 wherein
the maleinated asphalt D was used as the asphaltic material were
homogeneous ones because of satisfactory compatibility of the asphaltic
material with each of the epoxy resins A, B and C. On the other hand, it
was also found that the compositions of Comparative examples 1, 2 and 3
wherein 80/100 straight asphalt was used were each separated into two
layers because of poor compatibility of the asphaltic material with each
of the epoxy resins A, B and C.
Table 1
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Asphalt composition
(parts by weight)
Epoxy resin
Asphaltic material
Compatibility
__________________________________________________________________________
Example
1 A (100)
Maleinated asphalt D
(100)
Satisfactory
" 2 B (100)
" (100)
"
" 3 C (100)
" (100)
"
Comparative
example
1 A (100)
80/100 Straight
(100)
Poor
asphalt
" 2 B (100)
" (100)
"
" 3 C (100)
" (100)
"
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EXAMPLES 4-5
The composition of Example 4 comprising the epoxy resin B and the
maleinated asphalt D had a penetration of 106 and, after heated to
130.degree. C. for 12 hours, it was converted to a composition having a
penetration of 35. The composition of Example 5 comprising the epoxy resin
B, the maleinated asphalt and the curing agent I had a penetration of 115,
and it was converted to an asphalt composition having a penetration of 17
by heating the former to 140.degree. C. for two hours. From this result it
was found that the curing was accelerated by heating and that the curing
was further accelerated by heating in the presence of the curing agent
added thereby shortening the reaction time.
EXAMPLE 6
The composition of Example 6 comprising the epoxy resin B and the
maleinated asphalt ester F was blended together at 130.degree. C. for 5
minutes and then allowed to stand at 130.degree. C. for 48 hours for the
curing thereof, thereby obtaining a uniform or homogeneous asphalt
composition having a penetration of 29.
COMPARATIVE EXAMPLES 4-6
The maleinated asphalts D, E and the maleinated asphalt ester F had a
penetration of 75-95 and were unsatisfactory in hardness as compared with
the compositions obtained in Examples 4-6.
COMPARATIVE EXAMPLE 7
Fifteen (15) parts by weight of styrene-butadiene rubber (average molecular
weight of 200,000) and 100 parts by weight of 80/100 straight asphalt were
heated to 160.degree. C. for two hours, incorporated with 1.5 parts by
weight of maleic anhydride and heated to 170.degree.-180.degree. C. under
agitation for two hours. The resulting reaction product had a penetration
of 53 and was unsatisfactory in hardness as compared with the compositions
obtained in Examples 4-6.
Table 2
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Asphalt composition (parts by weight)
Curing agent
Resin or polymer
Asphaltic material
for epoxy resin
Penetration
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Example
4 Epoxy resin B
(100)
Maleinated asphalt D
(230)
-- 35
" 5 " (100)
Maleinated asphalt E
(300)
I (4) 17
" 6 " (100)
Maleinated asphalt ester F
(300)
J (4) 29
Comparative
example
4 -- Maleinated asphalt D
-- 75
" 5 -- Maleinated asphalt E
-- 95
" 6 -- Maleinated asphalt ester F
-- 95
Comparative
example
7 Reaction product obtaind by heating S-B rubber
--5) 53
and 80/100 straight asphalt (100) and then
maleinating the resulting mixture with maleic
anhydride (15).
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EXAMPLES 7-8
The composition of Example 7 comprised the epoxy resin B, maleinated
asphalt G and curing agent J, and the composition of Example 8 comprised
the epoxy resin B, maleinated asphalt H and curing agent J. These
compositions were tested for tensile strength in order to study the
strength and flexibility thereof. The tests were carried out as follows.
These compositions were each agitated at 60.degree. C. for two minutes,
poured into a stainless steel dish in such an amount as to form a 4 mm
thick layer therein and then heated to 130.degree. C. for 3 hours for
curing. Test pieces, 10 mm wide and 4 mm thick, were prepared from the
layers so cured in accordance with the No. 2 type test pieces prescribed
in JIS (Japanese Industrial Standard) K 7113-1971 and they were tested at
25.degree. C. and 20 mm/min. for tensile strength and elongation in
accordance with JIS K 7113-1971. The results are shown in the following
Table 3.
COMPARATIVE EXAMPLE 8
A mixture of epoxy resin C, 80/100 straight asphalt and curing agent J as
shown in Table 3 was heated to 60.degree. C. under agitation for 30
minutes, but it yielded an unhomogeneous composition. The composition so
yielded was tested in the same manner as in Examples 7-8 with the results
being shown in Table 3.
Table 3
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Asphalt composition (parts by weight)
Maximum
Curing agent
tensile
for epoxy
strength
Elongation
Resin Asphaltic material
resin (kg/cm.sup.2)
(%)
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Example
7 Epoxy resin
C (100)
Maleinated asphalt G
(1580)
K (75) 2.1 60
Example
8 " C (100)
Maleinated asphalt H
(1580)
K (75) 3.4 25
Comparative
example
8 " C (100)
80/100 Straight asphalt
(1600)
J (4) 1.3 20
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From the above results it is apparent that the asphalt compositions of the
present invention have satisfactory strength and flexibility.
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