Note: Descriptions are shown in the official language in which they were submitted.
INSULATED ~LASS AND SEALANT THEREFOR
~ield of the Invention
This invention relates to a composition which has a combination of
properties which makes it particularly useful for use as a sealant for
insulated glass.
The term "insulated glass" broadly refers to a structure comprising
panes of glass, the faces of which are in spaced relationship, thereby pro-
viding between the glass panes a space which imparts insulating properties
to the structure. In its most widely used form, 2 parallel panes of glass
are positioned in spaced relationship by metallic spacers positioned around
the perimeters of the panes, and indented a short distance from the edges oE
the panes, thereby forming a U-shaped channel in which the legs of the U
comprise the interior surface edges of the panes and the base of the U com-
prises a side of the spacer. In typical form, the spacer is a hollow member
filled with a water-absorbent material, for example, a molecular sieve, for
keeping the enclosed air space between the glass panes dry. In such a
structure, the aforementioned U-shaped channel is filled with a sealant,
generally a polymeric-based composition, which must have a combination of
properties for satisfactory use.
Required properties of a satisfactory sealant are discussed below.
The sealant must have a very low moisture vapor transmission (~IVT)
rate so that molsture is prevented from entering the dry space between the
panes of glass. The presence of moisture in the space tends to reduce the
insulating value thereof. Moisture in the space can also condense on the
panes of glass and create visibility or aesthetic problems. It should be
appreciated that if the sealant does not have a satisfactory low MVT rate,
the absorbing capacity of the water-absorbent material in the hollow spacer
will be exceeded, arld molsture will find its way into the space.
Another property of the sealant is that it should form an excellent
bond with glas6 which is not degraded over long periods o~ time under use
conditions, which generally include exposure to sunlight, moisture and large
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~k
changes in temperature.
In addition, the sealant itse]f must not be a source of a material
which enters the space between the panes of glass and causes fogging thereof.
For example, if under the conditions of use~ one or more constituents com-
prising the sealant volatize into the space, fogging, often referred to as
"chemical fogging" of the glass panes is encountered.
In addition, the sealant shoulcl have good elongation or flexibllity
properties so that it gives during contraction and expansion of the insulated
glass structure. Changes in temperature will tend to cause this. According- -
ly, the sealant should have an elongation of at least about 100%, and pre-
ferably an elongation of at least about 200%.
The sealant should also resist being degraded when contacted with
conventional caulks and putties.
The present invention relates to a composition having a combination
of properties which make it ideally suited for use as a sealant for insulated
glass.
Reported Developments
At present, the most widely used insulated glass sealants are
prepared from polysulfide liquid polymers, selected plasticizers, and glass
adhesion promoters such as silanes. ~xamples of plasticizers used in such
sealants are high boiling phthalates and chlorinated paraffins. In the past,
chlorinated biphenols were used as plasticizers in polysulfide-based sealants. ~-
Speaking generally, the aforementioned type sealant is applied in liquid
form and then cured by the use of a curing agent such as manganese dioxide.
A serious disadvantage of the aforementioned polysulfide-based
sealant is its relatively high cost~
The use of polymers other than polysulfides for glass insulated
sealants has been reported. For example, United States Patent No. 3,372,083
discloses an insulated glass sealant which is the cured reaction product of:
A~ an isocyanate terminated prepolymer; and
B) an isocyanate adduct of a bituminous substance containing
asphaltene or tar~like compounds.
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.
Although compositions within the scope of this patent have been used
satisfactorily in certain applications, it is believed that they have not
been used commercially as sealants for insulated g:Lass because they lack one
or more oE the properties referred to above.
Accordingly, it is an object oE this invention to provide a
composition which has a combination of properties which make it e~fective
for use as a sealant for insulated glass.
Summary of the Invlention
In accordance with this invention, there is provided a composition
comprising a plasticized cured polyurethane or a plasticized cured polyether
having a moisture vapor transmission rate, as measured by a heat-accelerated
MVT test (described in detail below), of no greater than about 1 g per day,
an elongation of at least about 100%, and low volatility properties. Con-
ventional glass-adhesive improvers can be added to the above composition to
provide a sealant which forms an excellent bond with glass and metal, and a
bond which resists degradation over years of use under the various conditions
to which insulated glass is exposed.
According to one aspect the invention provides insulated glass
including as a sealant therefor a composition comprising a plasticized cured
polyurethane or a plasticized cured polyether and a plasticizing material,
the water absorption properties of the plasticizing material, as determined
by ASTM D-570, being less than about 0.1 wt. %; and the volatility properties
of the plasticizing material being such that the product of
i the vapour pressure of the plasticizing material in mm of Hg
at 480 F. and
ii the concentration of the plastici7ing material in the composi-
tion in wt. % is not greater than about 1200;
said polyurethane or said polyether comprising about 20 to about 50 wt. % of
the composition and said plasticizing material comprising about 20 to about
60 wt. % of the composition and the composition further comprising from 0 to
40 wt. % of filler.
According to a further aspect the invention provides a plasticized
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~ . .
~1 .
,
- .. .
. - ,~ - - , .
cured compositlon having a moisture vapour transmission rating oE no greater
than about 1 g/day, an elongation of at least about 100% and low volatllity
and comprising:
A about 30 to about 40 wt. % of a polyurethane which is the reaction
product of a hydroxyterminated polybutadiene and tolylene diisocyanate or
methylene bis-(4-phenyl isocyanate);
B about 20 to about 35 wt. % of plasticizing material, said material
comprising about 3 to about 20 wt. % oE coal tar having a distillation point
of no lower than about 500F. or rooEing asphalt having substantially no
volatiles at temperatures up to about 500 F., and said coal tar and said
asphalt having substantially no weight loss for 24 hours at 200 F. or poly-
butene having a weight loss of about 1% or less when subjected to ASTM D-972
for 10 hours at 210 F. or a mixture thereof, and about 80 to about 97 wt. %
of phthalates having a boiling point of 450 F. or higher at 10 mm Hg or
aromatic resins or aromatic oil or a mixture thereof;
C about 20 to about 35 wt. % of filler;
D about 2 to about 6 wt. % of thixotropic agent; and
E about 0.5 to about 2.5 wt. % of a glass adhesion promoter.
- According to yet a further aspect the invention provides a plastic-
ized cured composition including a cured polyurethane or a cured polyether
and wherein said composition has a moisture vapour ~ransmission rating of no
greater than about 1 g/day, an elongation of 100% and low volatility and
wherein said cured polyurethane or said cured polyether is derived from a
water-sensitive poIyether including a polyethylene or polypropylene glycol
and wherein said composition comprises:
A about 30 to about 40 wt. % of said cured polyurethane or said
cured polyether;
B about 35 to about 55 wt. % of plastlcizing material, said material
comprising about 25 to about 75 wt. % of coal tar having a distillation point
of no lower than a~out 500F. or roofing asphalt having substantially no
;~ ~ volatiles at a temperature of up to about 500 F.; and said coal tar andsaid asphalt having substantially no weight loss for 24 hours at 200F. or a
!
~ ~ -4-
~ . . . . .
mixture thereof and about Z5 to about 75 wt. % of chLorinated paraffins
having a chlorine content of at least about 40-70 wt. % or of phthalates
having a boiling point oE 450F. or higher at 10 mm Hg or a mixture thereof;
C about 5 to about 30 wt. % of filler;
D about 2 to about 6 wt. % thixotropic agent; and
E about 0.5 to about 2.5 wt. % of a glass adhesion promoter.
In a further aspect the invention provides a plasticiæed cured
composition having a moisture vapour transmission rating of no greater than
about 1 g/day, an elongation of at least about 100% and low volatility and
comprising:
A about 30 to about 45 wt. % of polyurethane prepared by reacting a
prepolymer of hydroxyl-terminated polybutadiene and tolylene diisocyanate with
butanediol; and
B about 25 to about 35 wt. % of a plasticizing material comprising:
i phthalate having a boiling point of 450 F. or higher at 10 mm
Hg; or
ii a mixture of about 5 to about 95 wt. % of said phthalate and 5
to about 95 wt. % of asphalt having substantially no volatiles at temperatures
up to about 500 F. and substantially no weight loss for 24 hours at 200 F.;
or
iii a mixture of about 5 to about 95 wt. % of said phthalate and
about 5 to aboat 95 wt. % of polybutene having a weight loss of about 1% or
less when subjected to ASTM D-972 for 10 hours at 210F.;
C about 25 to about 35 wt. % of talc or calcium carbonate filler; and
D about 0.5 to about 2.5 wt. % of glass adhesion promoter; and
E about 3 to about 5 wt. % of thixotropic agent.
As will be described in detail below, it has been found in accor-
dance with this invention that either of the aforementioned polymers can be
combined with various modifying materials, referred to herein as "plastlcizing
materials"~ and other additives to form compositlons which have properties
required of satisEactory sealants for insulated glass.
One of the significant advantages of the present invention is that
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. . . . . . . '
relatively low-cost ingredients can be used in pre-paring the sealant without
sacrificing any of the various properties that satisfactory sealants must
have. Indeed, sealants within the scope of the present invention have pro-
perties that exceed industry accepted standards.
It is noted that polysulfide-based sealants have been the only
curable insulated glass sealants in commercial use for about 15 years. The
characteristics of such sealants which have led to this use are: a low MVT;
the ability to be applied in the form of a liquid which cures to a rubbery
seal; the ability to adhere to glass and aluminum when adhesion promoters
are added; and the capability of retaining this aclhesion when the insulated
glass unit is subject to a reasonable cycle of weathering, moisture exposure
and ultraviolet light exposure.
Although urethane polymers and polyethers have been available during
the aforementioned period of time, they have never qualified as glass sealants
due to several deficiencies. Sealants based on such polymers have poor ad-
hesion to many substrates, do not have as low an MVT as polysulfide-based
sealants, are more hydrolysis prone, and do not have the adhesion retention
required to maintain the desired long term seal of the insulated glass units.
Sealed Insulated Glass Manufacturer's Association, the industry
association referred to as "SIGMA", has generated a simulated weather cycling
test, covering three months of testing, which has been established as the
standard of performance for finished units and for the sealants used. Most
common urethane polymers based on polyether polyols have a compounded MVT
2-3 timee higher than polysulfides, are subject to hydrolysis and weathering
degradation and do not allow the units to pass through the SIGMA test cycle
with the required retention of seal, low inner unit moisture and the minimum
dew point limit and standard. Until the sealant of this invention passed
the test, lt is believed that no o~ther polyurethane-based polymer met the
full requirements to obtain SIGMA certification.
By way of example, under one user's test cycle, w~here polysulfide-
based sealants usual:Ly last 8 weeks before failure and their lasting 10 weeks
is unusual, and where one manufacturer's sealant lasts for only 4 weeks, the
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.. .. .
ealant oE the present invention lasted for 12 weeks with no drop in dew
point. This excellent performance contrasts to a drop in dew point for
polysulfide-based sealants from -94 F to 0 F (test failure) usually in 8
weeks.
In effect, the present invention involves converting what is
normally regarded as a poor weathering polymer into a superior sealant with
outstanding properties for insulated glass units which are subjected during
their lives to difficult weathering cycles.
Detailed Desc~ption of the Invention
]0 In evaluating properties of compositions described below, the
following evaluation tests were used.
Tests
MVT Rate Test
A sample of the composition to be tested is prepared in the form
of a disk about 4" in diameter and 60 mils thicko The open end of a one
quart can filled with 200 g of water is tightly covered with the test sample
using a polyurethane adhesive. The can is placed in an oven having a tempera-
ture of 135-140 F. At various time intervals of at least a day, the amount
of water which evaporates from the can through the test sample is determined
by weighing. Results are reported in weight of water lost per day. A test
sample having an MVT rating of 1 gram of water per day or less is considered -
to have satisfactory moisture vapor transmission properties for use as a
sealant for insulated glass. An MVT rating in excess of about 1 g of water
per day is considered to be unsatisfactory. This test correlates well with
other standard tests.
Elongation_Test
A sample oE the composition to he tested in the form of a strip
having a thickness of about 60 mils, a vidth of about 1/2" and a length of
about 1~' is placed on a ruler and held at one end while the other end is -~ -
pulled u~til the str:Lp tears. The percent of elongation is determined by
dividing the difference between the length of the stretched strip and the
original length of the strip by the original length of the strip and -multi-
~ _7_
,.`~ -
.. . . ~... ...
.-. - , . ... . , . ~
plying the quotient by 100. A test sample having an elo~gation of 100% or
more is considered to have satisfactory elongation properties for use as a
sealant. If the strip tears before it is stretched to twice its length, that
is, the elongation of the sample is less than 100~, it has properties which
are considered to be unsatis~actory for use as a sealant in insulated glass.
Volatility Tests
A sample oE the composition is applied to a small scale model of
insulated glass, the structure of which consists of 2 panes of glass, about
4" x 4", separated by a metallic spacer about 3/8" in width and positloned
around the entire perimeter of the glass panes, about 3/8" from the edges
thereof. The insulated glass is placed in an oven having a temperature of
about 180 F for a 12~day period. The cured composition has satisfactorily
low volatility properties if no fogging of the inside surfaces of the glass
panes occurs during the 12-day period. If fogging occurs, the composition
is not satisfactory.
Another test utilized to evaluate the volatility properties of
the cured composition consists of partially submerging the insulated glass
model in a pan of cold water and shining a sun lamp on the exposed portion
of the model from a distance of about 6 inches. The cured composition has
satisfactorily low volatility properties if no fogging or condensate appears
on the inside surfaces of the glass panes within a period of 2 days. If
fogging or condensate appears on the inside surfaces of the glass panes prior
to the expiration of a 2-day period, the cured composition does not have
satisfactory volatility properties.
When the term "low volatility" is used herein in connection with
the cured composition, it means that the cured composition has satisfactorily
low volatility properties as determined by the aforementioned tests.
Ingredients of Composition
The composition of the present invention includes either a cured
30; plasticized polyurethane or a cured plasticized polyether polymer. As will
be discussed in detail below, the specific materials used in plasticizing
the polymers will depend on the specific properties of the cured polyurethane
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or cured polyether polymer that is used. There follows immediately ~elow
a detailed description of the aforementioned polymers that call be used, and
thereafter a detailed description of other materials comprising the composi-
tion. Thereafter, guidelines are set forth as to the use of particular
combinations of the polymers and other materials.
Polyurethane
The cured polyurethane constitnent of the composition of the present
invention is the reaction product of an organic polyisocyanate and polyol or
the cured reaction product of a prepolymer containing free -NC0 groups.
The polyisocyanate reactant for use in the practice of the present
invention is any ma~erial which contains two or more NC0 groups in the mole-
cule. The polyisocyanate can be an aliphatic or aromatic polyisocyanate
including, Eor example, cycloaliphatic, aryl, aralkyl, and alkaryl polyiso-
cyanates. As will be explained in detail below, it can also be a higher
molecular weight adduct or reaction product prepared by reacting an excess
of a polyisocyanate with a polyfunctional compound containing active hydrogen,
such adducts or reaction products generally being referred to as prepolymers.
Examples of aliphatic polyisocyanates which can be used are:
ethylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate,
etc; other alkylene diisocyanates, such as propylene-1,2-diisocyanate,
butylene-1,2-diisocyanate, butylene-1,3-diisocyanate, butylene-2,3-diiso- ;
cyanate, etc.; alkylidene diisocyanates, such as ethylidene diisocyanate,
butylidene diisocyanate, etc., cycloalkylene diisocyanates, such as cyclo-
pentylene-1,3-diisocyanate, cycIohexylene-l ? 4-diisocyanate, 4,4'-diisocyanato
bis(cyclohexyl)methane, etc.; p-phenylene-2"?'-bis(ethyl isocyanate); p-
phenylene-4,4'-bis(butyl isocyanate); m-phenylene-2,2'-bis(ethyl isocyanate);
1,4-naphthalene-2,2'-bis(ethyl isocyanate); 4,4'-diphenylene-2?2'-bis~ethyl
isocyanate); 4,4'-diphenylene ether-2,2'-bis(ethyl isocyanate); tris(2,2',2"-
ethyl isocyanate benzene); 5-chloro phenylene-1,3-bis(propyl-3-isocyanate);
5-methoxy phenylene-1,3-bis(propyl-3-isocyanate); 5-cyano phenylene-1,3-
bis(propyl-3-i:ocyanate); and 5-methyl phenylene-1,3-bis(propyl-3-isocyanate).
Examples oE aromatic polyisocyanates which can be used include:
,~ ~9~ ~ :
~ .
tolylene diisocyanate; m-phenylene diisocyanate; p-phenylene diisocyanate;
l-methyl-2,4-phenylene diisocyanate; naphthylene-1,4-diisocyanate; diphenylene-
4,4'-diisocyanate; xylylene-1,4-diisocyanate; xylylene-1~3-diisocyanate; and
4,4'-diphenylenemethane diisocyanate.
Any material containing a plurality of hydroxyl groups can be used
for reacting with the polyisocyanate constituent to form the set or cured
composition of the present invention. Examples of classes oE such materials
include hydroxyl polyesters, po]yhydric polyalkylene ethers, polyhydric
polyalkylene thioethers, and hydroxyl-terminated diene polymers.
Hydroxyl polyesters comprise the reaction mixture of a polycarboxylic
acid and a polyhydric alcohol. Examples of the aforementioned acid are
succinic, adipic, azelaic, phthalic, terephthalic, maleic, and itaconic.
Examples of polyhydric alcohols are ethylene glycol, propylene glycol,
butylene glycol, 1,6-hexane diol and pentaerythritol.
Polyhydric polyalkylene ethers are the condensation product of an
alkylene oxide with a small amount of a compound containing active hydrogen-
containing groups such as, for example, water, ethylene glycol, propylene
glycol, butylene glycol, trimethylolpropane, and glycerine.
As to the polyhydric polyalkylene thioethers, they can be prepared
by reacting alkylene oxides, such as those mentioned above, with a polyhydric
thioether such as, for example, thiodiglycol, 3,3'-dihydroxypropyl sulfide,
4,4'-dihydroxylbutyl sulfide, and 1,4-(beta hydroxyethyl) phenylene dithio-
ether.
Hydroxyl-terminated diene polymers that can be used are ones which
have the hydroxyl groups present in predominately primary, terminal positions
~; on the main hydrocarbon chain and allylic in configuration. Dienes which are
employed to make the aforementioned polymers are unsubstituted, 2-substituted,
or 2,3-disubstituted 1,3-dienes of up to about 12 carbon atoms. Preferably,
the diene has up to 6 carbon atoms and the substituents in the 2-, and/or 3-
position may be hydrogen, lower alkyl of about 1 to about 4 carbon atoms, aryl
(substituted or unsubstituted), halogen nitro and nitrile. Examples of dienes
which can be used are l,3-butadiene, isoprene, chloroprene, 2-cyano-1,3-
.
~1 i --10--
butadiene, and 2,3-dimethyl-1,3-butadiene. Excellent results have been
obtained utilizing liquid resins which are hydroxyl-terminated homopolymers
and copolymers of butadiene, examples of such copolymers being styrene/
butadiene and acrylonitrile/butadiene. Such materials are sold commercially
under the trademark "Poly bd", specific product designations being R-15~,
R-45M, R-45HT, CS-15 and CN-15.
In preparing the cured polyurethane composition from the polyiso-
cyanate and polyol, all of the ingredients comprising the composition are
admixed, and the hydroxyl groups react to form the cured polyurethane. In
this type of reaction, often referred to as a "one-shot" reaction, the poly-
isocyanate can be used in amounts ranging from about 95 to about 200 wt. %
of the calculated stoichiometric amount of the polyol used. Suitable well
known catalysts can be used in the reaction.
The cured polyurethane can also be prepared from a prepolymer
which is the reaction product of a polyisocyanate and a polyhydroxy compound
such as, for example, a hydroxyl-terminated polyester resin, a hydroxyl-
terminated polyether and a hydroxyl-terminated polydiene resin. In pre-
paring such prepolymers, a molar excess of the polyisocyanate is reacted with
the polyhydroxy compound, for example, one having a molecular ~eight of about
200 to about lO,000, in order to produce a reaction product or prepolymer that
contains at least two unreacted isocyanate groups per molecule. Thus, the
prepolymer contains a multiplicity of -NC0 groups which are capable of reacting
to set the composition.
The aforementioned prepolymers and methods for preparing them are
well known. Speaking generally, the aforementioned hydroxyl-terminated
; polyester resin reac~ant that can be used in preparing the prepolymer is
itself the reaction product of a polybasic acid tusually a dibasic acid) and
a polyhydroxy compound such as, for example, ethylene glycol, tetramethylene
gIycol and hexamethylene glycol. Examples of hydroxyl-terminated polyethers,
~30 also commonly referred to as polyether glycols, that can be reacted with the
polyisocyanate to form the prepolymer are polyethylene ether glycol, poly-
propylene ether glycol, polytetramethylene ether glycol and poly (oxypro-
'` .
.. . .
.
~ ~ 4~
pylene) triol or other oxyalkylene adducts of polyols, such as ethylene and
dipropylene glycol, and other polyols such as glycerine, trimethanol propane,
pentaerythritol, and sucrose. The prepolymer can also be prepared from
hydroxyl-terminated polydiene resins described above.
One of the important economic advantages of the present invention
is that of the many polyisocyanates that are known, sealants having excellent
properties can be obtained by using those that are readily available at
relatively low cost. These polyisocyanates include toluene diisocyanate
(hereafter referred to as "TDI"), including for example, a commercially
available mixture containing about 80% of 2,4-TDI and 20% of 2,6-TDI, and
methylene bis-(4-phenyl isocyanate) (hereafter referred to as "MDI"), includ-
ing a commercially available material often referred to as "crude MDI't. Such
polyaryl polyisocyanates are sold commercially by Upjohn Company under the
trademark PAPI, by Mobay Chemical Company under the trademark MONDUR MR,
and by Upjohn under the trademark Isonate.
Similarly, relatively low cost, commercially available polyols
and prepolymers can be used as the polyol reactant. Such materials are
available under the trademarks Niax, Isofoam and Pluracol.
Polyether Polymer
2n Polyether polymers useful in preparing the composition of the pre-
sent invention are those in which the major portion of the polymeric chain
is comprised of polyalkylene ether group and in which the polymeric chain
is terminated at each end with reactive groups such as hydroxyl, mercaptan
or epoxy groups. Such polymers are liquid and can be cured through the
reactive terminal groups by the use of conventional curing agents or
catalysts, for example, oxidi~ing agents and amines, into solid materials.
Curing of such polymers yields higher molecular weight polymers comprising
mainly a polyether backbone linked together by the reaction of their terminal
groups. The performance of the cured polymer corresponds mainly to its
polyether content which compxlses about 90 wt. % or more of its structure.
Examples of the aforementioned liquid polymers are polyalkylene
ethers having terminal hydroxyl groups at each end of the polymer, for
2-
.~.;i
example, those oE the fonnulas H~OR)n-OM wherein R ls C2H4, C3Fl6 or C~H8
and wherein n is a number such that the molecular weight of the polymer is
within the range oE about 400 to about 4000. An example of such a poly-
alkylene ether is sold under the trademark PPG 2000; it is a polypropylene
ether having a molecular weight of about 2000.
Diepoxy terminated polyethers can be derived from the polyalkylene
ethers mentioned immediately above. An example oE a diepoxy terminated
polyether which is curable with an amine is sold under the trademark
Dimeric.
Plasticized polymeric compositions within the scope of the present
invention can be also prepared from mercaptan terminated polyethers, for
example, those of the formula
HEo-CH-CH23 SH
R
wherein R is hydrogen or an alkyl group containing 1 to about 6 carbon atoms
or phenyl, and wherein n is a number such that the molecular weight of the
polymer is within the range of about 200 to about 6000. Such polymers can be
prepared through ring opening of epoxy compounds by anionic polymerization
cataLyzed by HS ion. Preferred liquid polymers are those having a molecular
weight of about 2000 to about 4000 and are commercially available. In the
practice of the present invention such polymers can be cured according to
conventional techniques, for example, by curing with an oxidizing agent such
as lead peroxide, manganese dioxide or calcium dioxide.
Plasticizing Materials
The plasticizing material for use in the composition of ~his inven-
tion is characterized by~having low volatility and low water absorption pro-
perties. It will be seen from the discussion below that a variety of differ-
ent types of plastic: Lzing materials and mixtures of such materials can be
used. Guidelines that can be used in selecting the plasticizing material are
related to the follo~ing properties thereof: the water absorption properties
of tne plastici7in~ material, as determined by ASTM D570, are less than about
0.1 wt. %; and the volatility properties of the plasticizing material are such
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:~ - :.: . , . , , : - . : : , . . .
that the product oE (i) the vapor pressure of the plasticizing material in
mm of Hg at 480 F and (ii) the concentration of the plasticizing material in
the composition in wt. % is not greater than about 1200.
There follows a detailed description of exemplary plasticizing
materials that can be used. It should be noted that the materials generally
fall within two basic classes of materials, namely, (A) relatively low
molecular weight materials that are known in the plastic industry as
plasticizers, for example phthalates, ch]orinated hydrocarbons~ diesters and
aromatic oils, and (B) relatively high molecular weight resinous and polymeric
materials, for example, coal tars, asphalts, polybutenes, and hydrocarbon and
hydrocarbon modified resins derived from low molecular weight compounds and
monomers of materials of coal, pinetree or petroleum origin. It should be
understood that the plasticizing materials described in detail below are
exemplary and that other plasticizing materials which have the aforementioned
low water absorption and low volatility properties mentioned above can be
used also.
Selected coal tars can be used to prepare the composition. The
coal tar should have a distillation point of no lower than about 500 F, and
preferably a distillation point of 600 F or higher. The coal tar is prefer-
ably a pourable liquid at room temperature, but it may also be a solid which
upon heating to a temperature of no greater than about 150 F-250 F becomes
a pourable liquid.
A special class of asphalts can be used as the plasticizing ingre-
dient. The asphalt that is suitable is roofing grade asphalt, a commercially
available material which has substantially no volatiles at temperatures up to
about 500 F. Roofing grade asphalt is essentially a solid that slightly
softens at a temperature of 80~100 F, and it becomes pourable at temperatures
of 150 F or higher. By way of example, commercially available roofing grade
asphalt that has a softness of 20/40 or 60/70 rod penetrometer can be used.
Selected coal tars, asphalts and other by-product tars for use in
the sealants of the present invention must have a very low volatility, as
evidenced by substantially no weight loss (about 0.5 wt. % or less) when left
'
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exposed in a hot air-circulating oven for 24 hours at a temperature of about
200 F. Developmental work has shown that the use in sealants of materials
having such volatility properties results in sealants which have satisfactory
volatility properties, that is, they do not vGlatilize into the insulated
glass unit and do not deposit chemical fog on the inner surfaces of the glass
panes. To pass the SIG~ test, there must be no chemical fogging after the
unit is subjected for 14 days to a temperature of 150F. l`he conditions of
the test include a U.V. lamp as a heat source and a cold metal condenser
which is held against a section of the glass to condense any organic materials
that volatilize.
Another class oE plasticizing materials that can be used are hlgh
boiling phthalates, that is, those having a boiling point of 450 F or higher
at 10 mm Hg. Specific examples of such phthalates are as follows: benzyl
phthalate, a clear oily liquid having a molecular weight of about 445, a
boiling point at 10 mm Hg of about 470 F, a vapor pressure at 482 F of 15 mm
Hg and a flash point (C.O.C.) of about 440 F; alkyl benzyl phthalate, a clear
oily liquid having a molecular weight of about 368, a boiling point at 10 mm
Hg of about 485 F, a vapor pressure 480 F of 9.7 mm Hg and a flash point
(C.O.C.) of 445 F; and dialkyl phthalates, a clear oily liquid having a
molecular weight of about 414, a boiling point at 10 mm Hg of about 485 F,
a vapor pressure at 482 F of 9 mm Hg and a flash point (C.O.C.) of about
440 F. A commercially available form of said dialkyl phthalate is a mixture
of dialkyl phthalates wherein the alkyl groups are mixed C7, Cg, and C
predominately linear groups, which mixture is sold under the trademark
Santicizer 711. Commercially available forms of said benzyl phthalate and
said alkyl benzyl phthalate are sold respectively under the trademarks
Santicizer 278 and Santiclzer 261. Examples of other high boiling phthalates
are those sold under the trademark Jayflex and include dihexyl phthalateg
~ diisononyl phthalate, diisodecyl phthalate and ditridecyl phthalate, the last
two mentioned being partlcularly preferred. It should be understood that
other high boiling~phthalates can be used, provided they are high boiling as
de:cribed :bove :nd hav: low volatility.
:
15-
Another class of materials that can be used are chlorinated
paraffins with a chlorine content of at least about 40-70 wt. % and prefer-
ably as high as is available. Such materials have good plasticizing capacity,
good tack for adhesion and impart good elongation properties to the composi-
tion. The chlorine content of the paraffins appears to aid compatibility
and improve W resistance for many urethanes. An example of a suitable
chlorinated paraffin is sold under the trademark Escoflex CLP-52. This
material is a stabilized chlorinated paraffinic hydrocarbon produced by the
chlorination of straight chain high boiling hydrocarbons; it is a nearly
water-white, mobile liquid which has a low volatility, a chlorine content of
about 50-52 wt. %, a specific gravity at 25 C of about 1.2-1.25 and a viscos-
ity at 25C of about 3 to 18 poises. Another example of a suitable chlorin-
ated paraffin is sold under the trademark Escoflex CLP-59. This material is
also a stabilized chlorinated paraffinic hydrocarbon produced by the chlor-
ination of normal paraffinic hydrocarbons; it is a nearly water-white mobile
liquid which has a low volatility, a chlorine content of about 57-59 wt. %,
a specific gravity at 25 C of 1.35-1.36 and a viscosity at 25 C of about 15-
20 poises. Other commercially available chlorinated paraffins that can be
used are sold under the trademarks Chlorowax 50 and Chlorowax 70.
Polybutene is an additional class of materials that can be used as
a plasticizer. This polymer is generally made by polymerizing an isobutylene-
rich butene stream in the presence of a metal halide catalyst. The poly-
; butene can be a mixture of different polybutenes of varying molecular weights
and predominately of the structure
:
CH
, 3
(cH3)3-c-(cH2-c~n-cH=(cH3)2
wherein n is a number such that the average molecular weight of the poly-
butenes is within the range of about 850 to about 2500. The material is a
liquid polymer which should be relatively non-volatile as evidenced by a
weight loss of about 1% or lower when subjected to ASTM D-972 for lO hours
at 210 F. ~lso, typical polybutenes for use in this invention will evidence
~ 16-
'`~
;~ ;
substantially no volatility loss when heated to a temperature of about 500F,
and preferably substantially no such loss when heated to a temperature of
about 600 F. Commercially available polybutenes that can be used in the
practice of the present invention are sold under the trade mark Indopol,
specific product designations being H-100, H-300, H-1500 and H-1900.
Aromatic oils having low volatility are another class oE materials
that can be used as the plasticizer. Such oils are generally comprised of a
mixture of materials with a major weight percent of the oils cornprising
aromatics. Such oils are often used as processing oils for rubber goods.
Set forth below are exemplary characteristics of suitable aromatic oils.
PHYSICAL PROPERTIES Oil A Oil B
Viscosity SUS 100 F 3000 7000
Viscosity SUS 210~ 85.7 122.6
API gravity, 60 F 12.8 10.3
Specific gravity, 60 F.9806 .9979
Viscosity-gravity constant.932 946
l~eight~ molecular 375 395
Pour point, F 55 55
Volatility:
% ~t. loss, 22 hr. at 225 F 1.3 0.26
Flash point, COC, F 435 445
CHE~IICAL PROPERTIES
~olecular type analysis
Clay-gel, wt. %
Asphaltenes 0.1 0.1
Polar compounds 7.9 8.3
Aromatics 68.8 72.2
Total aromatics 76.7 80.5
Saturates 23.2 19.4
Carbon type analysis, %
Ca 37 41 :
Cn 28 24
Cp 35 35
-17-
, .
: - ~ . :
CH~MICAL PROPERTIES Oil A Oil B
Aniline point, F l:L6 107
The above aromatic oils are exemplary. Other aromatic oils, for example,
those comprising about 70 to about 85 wt % aromatics can be ~sed. Examples
of aromaLic oils that are commercially available are those sold under the
trademarks Sundex 770, Sundex 8125 and Paraflux 10.
Additional classes of materials that can be used as plastici~ing
ingredients are hydrocarbon and modified hydrocarbon resins derived largely
from low molecular weight compounds and monomers of coal, pinetree or petroleum
origin.
By way of example, there can be used highly aromatic, nonsaponifi-
able, nonpolar and nonreactive low molecular weight (for example, about 750
to about 1100 - number average) stable thermoplastic hydrocarbon resins
derived from petroleum monomers. Such resins are sold by Neville Chemical
Company under the trademark Nevchem and No. designations 100, 110, 120, 130,
and 140. They have ring and ball softening points within the range of about
100 to 140 C and an iodine number (ASTM D-1959) within the range of about
55 to about 65. Other exemplary aromatic resins produced from petroleum
derived monomers are sold by Hercules Incorporated under the trademarks Picco
(6000 Series) and Piccovar. Such resins include liquid and solid materials
having a ring and ball softening point within the range of about 70 to about
140 C. Other examples of aromatic petroleum-based thermoplastic hydrocarbon
resins, which are nonreactive and nonsaponifiable, are sold under the trademark
Nebony by Neville Chemical Company. They have ring and ball softening points
within the range of about 100 to 110~ flash points (C.O.C., F, ASTM D-92)
of about 560 to 565 and molecular weights (number average by Osmometry) with-
in the range of about 475 to 550 and an iodine number (Wijs, ASTM D-1959) in
the neighborhood of about 65. Another example of an aromatic type resin that
can be used is based largely on vinyltolune and is sold by ~lercules Incorpor- -
ated under the trademark Piccotex, for example, Piccotex 120 which has a ring
and ball softening point of about 120 C and a flash point (C.O.C.) of about
545 F.
-18-
.,
.. : .
~!9~
An example of an aliphatic petroleum-based resin is a cyclo-
pentadiene derived polymer such as that sold by Neville Chemical Company
under -the trademark Neville LX-1082. This resin, ~hich has good stability
has a ring and ball softening point of about 100C, a flash point (C.O.C.,
F, ASTM D-92) of about 425, an iodine number (Wijs, ASTM D-1959) of about
140 and a molecular weight (number average by Osmometry) of about 685.
Another example of a class of aliphatic resins comprise mainly polydicyclo-
pentadiene sold under the trademark Piccodiene by Hercules Incorporated. They
have ring and ball softening points within the range of about 100 to about
140 C and a flash point (CØC.) within the range of about 435 to about
490 F. Other aliphatic resins produced from petroleum-derived monomers are
sold under the trademarks Piccopale and Piccotac by Hercules Incorporated.
Still another example of an aliphatic resin is one made from mixed low
molecular weight monomers and sold by Hercules Incorporated under the
trademark Piccovar. S~ch resins having ring and ball softening points within
the range of about 165 to about 180 C and a flash point (CØC.) within the
range of about 570 to about 585 F.
Examples of chemically inert hydrocarbon resins which are coal
tar-based are coumarone-indene resins having a low iodine number which
ensures good oxidation resistance. An example of such a resin is one sold by
Neville Chemical Company under the trademark Paradene No. 2 and having a
ring and ball softening point of about 100 F, an iodine number (ASTM D-1959)
of about 65, a flash point (CØC., F, ASTM D-92) of about 525 and a mole-
cular weight (number average by Osmometry) of about 700. Other examples of
coal tar-based hydrocarbon resins are polyindene resins manufactured from
coal-derived unsaturated compounds. Such resins are sold by Hercules
Incorporated under the trademark Piccoumaron and have a ring and ball soften-
ing point within the range of about 100 to about ]20C and a flash point
(C.O.C.) within the rang~ of about 510 to about 540F. Piccoumaron 120 resin
is a specific example of such coal-derived resins.
Resin produced from monomers derived from both coal and petroleum
are sold by Hercules Incorporated under the trademark Piccomer. For example,
~ `19-
' .
:
f~
Piccomer 150 resin has a ring and ball soLtening point of about 153C and a
flash point (C.O.C.j of about 530 F.
An additional class of plasticizing materials that can be used are
aliphatic and aromatic diesters of the general formula '~
O O
Il 11
RO - C--~CH2 ~ C - OR
wherein "R" is an aliphatic or aromatic group having six or more carbon atoms
and "n" is about ~ to about 18. Examples of such diesters include: di-2-
ethylhexyl sebacate; di-n-butyl sebacate; di-n-hexyl sebacate; di-n-butyl
hexoate; di-n-hexylazelate; di-n-hexyladipate; di-(2-ethyl hexyl) adipate;
dibenzyl sebacate; dibenzyl adipate; dibenzyl hexoate; dibenzyl azelate.
It is noted that various of the commercially available plasticizing
materials may contain small quantities of relatively low molecular weight
materials having a relatively high volatility. (For example, this is
particularly true of hydrocarbon and modified hydrocarbon resins derived
from coal, pine oil and petroleum sources). Such higher volatility fractions
should be removed prior to use of the materials.
In utilizing the present invention on an industrial scale, it will
be convenient to sell the ingredients used to prepare a composition from a
prepolymer in a 2-package arrangement, one package including the prepolymer
and plasticizing material, and the other package including the catalyst or
other curing agent. For the purposes of package stability, the plasticizing
material should be free of materials which are reactive with the free NCO
groups of the prepolymer. If plasticizing materials such as coal tars,
asphalts, etc., contain materials such as, for example, water or amines, it
is recommended;that they be treated with lime or an isocyanate to dry the
material or to react with the aforementioned reactive materials to thereby
provide a stable non-reactive mixture. This will help insure package
stability.
The hasic constituents used in preparing the cured composition of
the present invention have been described above. Guidelines on the selective
use of the plasticiæing material and polymeric constituents follow. It is the
' ~
-20-
'
. : , ~ ,,
. . . . ..
~86~
selective combinatlon of these basic constituents which result in a composi-
tion that has the combination of properties that are required of a satisfac-
tory sealant for insulated glass.
The properties of the various cured polymers comprising the com-
position tend to vary from one to another. For example, some polyurethanes
are more hydrophobic than others. ~The term "hydrophobic" is used herein to
refer to the ability of a material to resist the flow oE water vapor there-
through. Accordingly, the more hydrophobic the material, the lower its MVT
rating.) Work has shown that cured polyurethanes based on hydroxyl-termLnated
polydiene resins, for example, butadiene resins thereof, have excellent
hydrophobic properties, whereas polymers based on water sensitive polyethers,
for example, polypropylene ethers, have relatively poor hydrophobic proper-
ties. Although it is possible to perhaps prepare compositions which have the
properties required of insulated glass sealants from hydrophobic polyurethanes
based on the afore~entioned diene resins, without the use of plasticizing
material, such compositions would be prohibitively expensive. In accordance
with the present invention, it has been found that cured compositions com-
prising as little as 20 wt. % cured polyurethanes prepared from such diene
resins have improved hydrophobic properties over those containing no
plasticizing material. Accordingly, the use of selected plasticizing materials
according to the present invention improves the hydrophobic properties of
very hydrophobic cured polymers and reduces the cost of the composition. In
addition, other properties of the cured composition can be improved through
the selective use of plasticizing materials.
As to those cured polymers which have relatively poor hydrophobic
properties, the selective use of plasticizing materials according to the
present invention results in cured compositions which have MVT ratings of
1 g/day or less. In~addition, other properties of the cured composition can
be improved and the cost lessened through the selective use of plasticizing
materials.
As to the capability of the plasticizing materials to impart
improved hydrophobic properties to the cured composition, work;has shown that
: : :
~ 21
, . . .
: ....... . . . .
;~'n38~
the following materials lis~ed in the order of relative performance, are
very effective: asphalt, greatest improvement; coal tars, coal tar
derivatives, aromatic and aliphatic hydrocarbon resins, and coumarone-indene
resins, almost as good; and followed by highboiling process oils such as the
commercial Sundex oils and the polybutenes, polyisobutylenes and polybutadiene
drying oils. It is believed that the hydrocarbon backbone of these materials
and the absence of oxygen and ether structures are responsible for the hydro-
phobic and water resistant properties of these materials. Work has further
shown that cured compositions comprised of the most hydrophobic polymers and
the most hydrophobic plasticizing materials have the lowest MVT rating.
Various factors other than the effect of hydrophobic improvement
by the plasticizing material may have to be taken into account in selecting
this constituent. Gne such factor is its compatibility with a particular
cured polymer. An incompatib:Le plasticizing material will tend to bleed out
of or exude from the cured composition promptly or upon aging, thereby adverse-
ly affecting the properties thereof. A particular plasticizing material may
be compatible with some cured polymers, but not with others, or it may be
compatible with a particular cured polymer, but only over a limited weight
range. As will be seen below, plasticizing materials which are not compatible
with a particular cured polymer may be made compatible therewith by the com-
bined use of one or more additional plasticizing materials. Another related
factor that should be taken into account is the selection of a material which -
is miscible with the liquid reactants used to prepare the cured polymer. (In
general, the plasticizlng material portion and the polymer-reactant portion
of the mixture will each be in the liquid state when the ingredients are
mixed. Heat may be used to melt or render flowable solid materials~. If
the ingredients are not miscible, separate liquid phases are formed with the
result that the properties of the cured composition are affected adversely.
A plasticizing material may be miscible with some reactants which are the
source of the cured polymer, but not with other reactants, or it may be
miscible therewith, but only over a limited weight range. As will be seen
below, plasticizing materials which are not miscible with certain reactants
:
~ -22- ~
~c, ~ 1
. . ,
may be combined with one or more other materials to form a mixture which is
miscible.
Other factors to take into account in selecting the plasticizing
material include the eEfect on elongation and toughness of the cured composi-
tion, the capability oE not interEering with the curing of the polymer and
the effect on viscosity of the liquid ingredients from the standpoint of ease
of mixing.
As illustrative of the above, it is noted that asphalt, an excellent
material for improving the hydrophobic properties to the cured composition,
is highly compatible with various polyurethanes based on hydroxyl-terminated
polybutadienes, but is only partially compatible with some cured mercaptan-
terminated polyethers, and is incompatible with polyurethanes made from
popularly used reactants. The use of liquid chlorinated paraffins in com-
bination with the asphalt provides a mix which is compatible with the afore-
- mentioned polymers. Also, upon heating a mixture of liquid chlorinated
paraffins and normally solid asphalt, a miscible liquid, which remains
liquid at room temperature, is obtained. Aromatic oils liquify asphalt at
lower temperatures, improve elongation of coal tarlpolyurethane compositions,
and in general improve flexibility of the cured polymers. Other plasticizing
mixes are illustrated in the examples below. Examples below show compositions
wherein upon mixing the reactants which form the cured polymer with the liquid
plasticizing componen~, there is obtained a homogeneous composition which in
its cured state contains plasticizing material that is compatible with the
cured polymer and does not separate or exude therefrom.
The composition of the invention can also contain optional miscellan-
eous ingredients, including, for example, filler, curing catalyst, a thixo-
: : :
tropic agent, and a glass adhesion promoter. The fillers used should be
hydrophobic, they can be used to impart improved hydrophobic properties to
,
the composition. Examples of fillers that can be used are talc~ titanium
dioxide, carbon blacl~, and finely ground sulfur. Any of the commonly used
~ curing catalysts can be used in curing the polyurethane or polyether polymers.
.
~ Examples of thixotropic agents that can be used are very fine asbestos fibers,
::: : ::
-23-
~: ::
colloidal sili~as, and clays, Eor example, bentonite. examples of glass
adhesion promoters t]lat can be used are silane ancl organic silanes having
from 2 to 3 alkoxy or hydroxy groups and from 1 to 2 organic groups terminated
with functional groups such as amino, epoxy or isocyana~e groups. Such
silanes are also effective in improving the adhesive bond between the cured
composition and a metallic surface. ~n general, the adhesion promoter
should comprise about 0.5 to about 2.5 wt. % of the composition.
The composition should comprise about 20 to about 50 wt %, prefer-
ably about 30 to about 45 wt. % of the polymeric constituent and about 20 to
about 60 wt. %, preferably about 20 to about 40 wt. % of plasticizing material.
Up to about 40 wt. %, and preferably about 20 to about 35 wt. % of the com-
position, can be comprised of filler. If the thixotropic agent is used, it
can comprise about 2 to about 6 wt~ % of the composition, preferably about
3 to about 5 wt. %.
Particularly preferred compositions comprise (A~ about 30 to about
40 wt. % of hydroxyl-terminated polybutadiene resin/TDI or ~DI polyurethane
and ~B) about 20 to about 35 wt. % plasticizing material, with the plasticiz-
ing portion comprising~
(i) about 3 to about 20 wt. % asphalt having substantially no
volatiles at temperatures up to about 500F. and substantially
no weight loss for 24 hours at 200F. or polybutene having a
weight loss of about 1% or less when subjected to ASTM D-972
for 10 hours at 210F., or a mixture thereof; and
(ii~ about 80 to about 97 wt. % of a phthalate having a boiling
point of 450F. or higher at 10 mm Hg.
.
~C) about 25 to about 40 ~t. % of filler.
W~en utilizing a polymer made from a water-sensitive polyether, for
example, polypropylene glycolJ it is preferred that the composition comprise
about 30 to about 40 wt. % of the polymer and about 35 to about 55 wt. % of
plasticizing material, with the plasticizing portion comprising: ~A) about
25 to about 75 wt. % asphalt or coal tar or a mixture thereof; and (B) about
25 to about 75 wt. % of chlorinated paraffins or high-boiling phthalates
- 24 -
(San-ticizer) or a mixture of one or more of -the same, (C) about 5 to about 30
wt. % of filler; (D) about 2 to about 6 wt. % thixotropic agent; and (E) about
0.5 to about 2.5 wt. % of a glass adhesion promoter.
Other cured compositions from wllich insulated glass sealants can be
prepared comprise about 25 to about 50 wt. % of a polyurethane prepared from
a hydroxyl-terminated diene polymer, preferably a hydroxyl-terminated poly-
butadiene, about 20 to about 40 wt. % of one or more of the following liquid
plasticizing materials; a phthalate having a boiling point of no less than
450F at 10 mm ~Ig; a chlorinated paraffin having a chlorine content oE at
least about 50 - 70 wt. %; a polybutene having a molecular weight within the
range of about 850 to about 2,500 and a weight loss of 1% or less when sub-
jected to ASTM D-972 for 10 hours at 210F; high melting aromatic or ali-
phatic resins; and a heat curable polybutadiene polymer, and about 10 to 40
wt. % iller. ~lso, one or more of the aforementioned liquid plasticizing
materia]scan comprise a portion o:E the mixture comprising one or more of the
following, the "wt. %" thereof being based on the total weight of the plasti-
ci7ing portion of the composition: about 30 to about 60 wt. % of coal tar;
about 30 to about 60 wt. % of roofing asphalt having substantially no
volatiles at temperatures up to about 500F; about 20 to about 40 wt. % of
aromatic oil; and about 40 to about 60 wt. % of an aromatic resin.
Another composition which can be used as a sealant for insulated
glass comprises about 2~ to about 50 wt. % o a cured polyurethane or a cured
polyether made from a water-sensitive glycol, including, for example, poly-
ethylene or polypropylene glycol, and about 40 to about 55 wt. % of a mixture
of plasticizing material, said mixture comprising: about 50 to about 90 wt.
% of coal tar or rooing asphalt or a mixture thereof; and about 10 to about
50 wt. % o one or more of the following li~uid plasticizing materials: a
chlorinatcd paraffin having a chlorine content of at least about 50 - 70 wt.
%; a phthalate having a boiling point of no less than about 450F; a poly-
butene having a molecular weight within the range of about ~50 to about
2,500; and an aromatic oil.
Sealant compositions having particularly good over-all properties
- 25 -
`
have bee~ prepared from compositions comprising:
(A) about 30 to about ~5 wt. % of polyurethane prepared by reac-t
ing a prepoly~er of hydroxyl terminated diene and a poly-
isocyanate; and
(B) about 25 to about 35 wt. % of a plasticizing material
comprising:
(i~ phthalate having a boiling point of ~50~. or higher at 10
mm llg; or
~ a mixture of about 5 to about 95 wt. % of said phthalate and
5 to about 95 wt. % of asphalt having substantially no vola-
tiles at temperatures up to about 500Q~. and substantially
no weight loss for 24 hours at 200C; or
(iiil a mixture of about 5 to about 95 wt. % of said phthalate and
about 5 to about 95 wt. % of polybutene having a weight loss
of about 1~ or less ~hen su~jected to ~ST~ D-972 for 10 hours
at 210F.; and
~C) about 25 to about 40 wt. % filler, preferably talc or calcium
carbonate; and optionally
(D) about Q.5 to a~out 2.5 wt. % of glass adhesion promoter; and
2~ (E) about 3 to about 5 wt. % of a thixotropic agent.
The preferred high boiling phthalates are ditridecyl phthalate or diisodecyl
phthalate. In the above formulation, the polyurethane can be prepared from
other hydroxyl-terminated dienes and polyisocyanates. W~en the polyurethane
is prepared from a prepolymer, other short chain polyols ~molecular weight
of no greater than about 200) can be used.
Examples
Examples below are illustrative of the invention.
The first two examples illustrate a plasticized cured polyurethane
prepared from MDI and a hydroxyl-terminated polydiene and a mixture of
plasticizers comprising roofing asphalt ~a$ described above) and a chlorinated
paraffin to render the asphalt miscible and compatible. The polydiene used
was Poly bd R-45HT, a hydroxyl-terminated polybutadiene having a hydroxyl
- 26 -
"
content of about 0.8 meq/~. The following 2-part mixtures were prepared
Eor each of the compositions.
E.x. No. 1 Ex. No. 2
Part A
roofing asphalt 14 g 11 g
chlorinated paraffin ~CLP-5~ 22 " 7 "
hydroxyl-term~nated butadiene 30 '( 15 "
low mol. ~t. diol chain extender
(~yandotte P245~ 12 " 6 "
car~on black dispersion15 " 8 "
dibutyltin dilaurate2 drops 1 drop
stannous octoate " " " "
Part B
~DI (Isonate 14-3L~ 11.5 g 5.75 g
talc 3 " 1.5 "
bentone 1 " 0.5 "
The ingredients comprising Part A o each of the examples were
heated ~ith mixing to a temperature of about 2U0~ until the asphalt had melt-
ed and the mix hecame homogeneous. Part ~ was allo~ed to cool to room tem-
perature at which it remained liquid. Part B was th0n added to Part A and the
compositions uere cured at room temperature. The ~VT of the cured composi-
tion of Ex. No. 1 was 0.52 g/day and that of No. 2 was 0.35 g/day. The
elongation of each of the cured compositions uas in excess of 100% and the
cured compositions had satisfactorily low volatility properties. The addition
of a glass adhesion promoter, for example, a silane to the above composition,
results in cured compositions whlch bond excellently to glass.
The next example is illustrative of a commerciall~ available com-
position and i5 presented for comparative purposes.
Exam~le A
A cured polyurethane composition ~as prepared from ingredients set
forth ~n E~ample No. 2 above except that there uere su~stituted ~or the roof-
ing asphalt and chlorinated paraffin the following: 2Q g of a 70% asphalt
cutback and 5 g of an aromatic oil (Sundex 7~0). The asphalt comprised about
~ 27 -
50 wt. % of the composition and the polyurethane 32.5 wt. % of the composition.
~lthough the MVT (0.2 g/day) of the cured composition was satisfactory, the
volatility properties thereof were not due to the solvent in the asphalt cut-
back.
F.xample Nos. 3 and 4
Two compositions were prepared from the same polyurethane reactants
used in Example Nos. 1 and 2 and in amounts such that the cured urethane
comprised 30 wt. % of the composition. One of the compositions contained
a~out 47 ~t. % chlorinated paraffin ~CLP-59~, and the other about 41 wt. % of
plasticizer with about 76 wt. % of the plasticizer portion comprising chlorin-
ated paraffins (CLP-59) and the remainder roofing asphalt. The MVT ratings
of the compositions were respectively 0.31 and 0.37 g/day (each measured
over a 27-day periodl. ~he elongations of the cured compositions were in
excess of 100%, and the volatility properties were satisfactory. The addi-
tion of glass adhesion promoters to the compositions results in the cured
forms thereof having excellent glass adhesion.
Examples Nos. 5-9
Ex. No. Ex. No. Ex. No. Ex. No. Ex. No.
Ingredients 5 6 _ 7 8 _ 9
Plasticizing Mats.
; high k~iling coal tar 10 40 -- 30 30
solid roofing asphalt 20 -- 30 -- --
chlorinated paraffins
~CLP-59) 10 12 -- 10 10
aromatic oil CSundex -- -- 11 -- ~-
8125)
Polyurethane Reactants
hydroxyl-terminated poly-
butadiene (R-45~1T) ~ lS 15 15 __ 12
lo~. mol. wt. diol chain
extender ~yandotte P2451 6 6 6 4 4
MDI (Isonate 143L) 6 7 5-1/2 5-1/25-1/2
polyether polyol CNias
LC-34~ -- -- -- 15 3
- 28 -~
.;.,. ~
`'
,., . .. : :-. ~ . , .,: .
Ex. No. Ex. No. Ex. No. Ex. No. Ex. No.
fi 7 8 9
Properties
~NT g/day 0.27 0.32 0.21 0.~6 0.~4
Elongation ~ in excess of 100% ------
Volatility ~ -- satisfactory
The above ex.~mples show the excellent hydrophobic properties impart-
ed to the cured composition by roofing asphalt and the good results obtained
utilizing high boiling coal tar. The examples also illustrate the use of
selected plasticizers to impart excellent hydrophobic properties to urethanes
made from normally water sensitive polyols.
Example No 10
Work has shown that roofing asphalt is incompatible with polyether/
NC0 prepolymers of -the type representative of those made from polyalkylene
ethers based on propylene glycol and of molecular weight about 2000 ~PPG 2025).
~lowever, other plasticizing materials can be used in com~ination with roofing
asphalt to achieve compatibility. For example, a 2 w~. % NC0 polyether based
; on PPG 2025 in combination with equal amounts of chlorinated paraffins ~CLP-
59~ and asphalt and cured as a l-part composition us:ing moisture from the
air, with a polyurethane content of 30 wt. %, gave an MVT of 0.~ g/day with
no incompatibility problems.
The next example illustrates the use ofa cured composition prepared
from a mercaptan-terminated polyether.
~xample No. 11
The compQsition comprised about 35 wt. % of a mercaptan-terminated
polyether and aboout 50 wt. % of a plasticizing mix, 25% of which comprised
chlorinated~paraffins ~CLP-591 and about 25 wt. % of roofing asphalt, with
the remainder of the composition comprising mainly filler. The composition
was cured utilizing manganese dioxide. The MVT of the cured composition was
0.5 g/day, its elongation~as in excess of loa%, and it had satisfactory
volatility properties. The~addition of a glass adhesion improver such as,
for example a silane to -the a~orementioned composition results in a cured
29 _
t~
. : :
' . . : ' ~
,
composition having excellent adhesion to glass.
The next follr examples are illustrative oE compositions having an
excellent combination of properties.
~mts. of Ingredients, in grams
Ex. No. Ex. No. Ex. No. Ex. No.
Ingredients 12 13 14 15
NCO ~ OH reactants
hydroxyl terminated poly-
butadiene (R-45HT) 650 46Q 460 650
polyether polyol (LC-34)100 90 90 100
low molecular weight diol (P245~180 120 120 180
MDI (Isonate 143) 270 185 185 270
Plasticizing Mats.
chlorinated hydrocarbon
(CLP-59~ 900
polybutene (H-100) 150 300 300 300
aromatic oil (Sundex 81251 150 --- --- ---
coal tar CNeo Rez LV2~ 600 --- ---
solid roofing asphalt --- --- 600 ---
Miscellaneous Ingredients
filler, mainly talc 375 325 325 375
catalyst, 40 wt. % dibutyltin
dilaurate and 60 wt. % stan-
nous octoate 5 5 5 5
thixotropic agent Casbestos~ 2ao 120 60 200
silane adhesion impro~er30 3Q 30 30
Properties of Cured Com~
~VT, g/day Q.5 Qc3 0.2 0.4
elongation 30Q% 325% 575% 300%
The glass adhesion properties of each of the abo~e compositions were evaluated.
In each case, there was cohesive failure of the composition and no failure of
the adhesive bond between the glass and the composit~on. Upon subjecting the
cured compositions to volatility testing as described above, there was no --~
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chemic~l fogging or condensate aCter 14 days of test~ng at 180F and no
chemical fogging or condensate after 3 days oE exposure to a sun lamp.
The next 2 examples are illustra~ive oE preferred compositions with-
in the scope of the present in~ention.
Amts. of ~ngredients, in grams:
Ingredients Ex. No. 16 Ex. No. 17
NCO ~ OH reactants
hydroxyl-terminated polybutadiene
~R-45HT) prepolymer with 6% NCO lOO 150
polyether polyol (LC 34~ pre-
polymer containing 3 wt. % free
NCO groups 550
polyether polyol ~PPG 20002 pre-
polymer containing 3 wt. % free
NCO groups - 400
polyether polyol (P 22Q~ prepolymer
containing 3 wt. % free NCO groups - 150
~DI (Isonate 143L2, drying agent 4a
Plasticizing Materials
chlorinated paraffins (CLP-59~300 600
asphalt 600 600
coal tar 3QO
Miscallaneous
talc 3Q0 300 -
CaO 6Q 60
silane 3Q 30
asbestos - 40
The above compositions are cured with diamimes or with dibutyltin
., :
dilaurate and water. The MVT ratings are respectively 0.3 and 0.4 g/day and
elongations are well in excess of lQQ%t The cured compositions are non-
~ ~olatile.
10 ~ ~ Some additional general observat;ons can be made respecting
~he plasticizing mater~al and polymeric components of the compasitions. In
preparing the composition from hydroxyl~terminated polybutadienes, the use
:
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:
.
:~`F : :
-
.
therewith oE polyols, for example, polypropylenes, generally improve ~he
elongation of the cured composi-tion without substantially af-fecting the hydro-
phobic properties of the composition. With respect to polybutene plasticiz-
ing materials, they are very effective in imparting good hydrophobic proper-
ties to the composition, but if the plasticizing portion compriscs 100 wt. %
of the polybutadiene, the cured composition will tend to be tacky. Also,
polybutenes tend to be incompatible with some cured polymers. Thus, it is
preferred that polybutenes be used in combination with another plasticizing
material, and that the polybutene portion thereof be no greater than about
75 wt. %. Although coal tar can comprise 100% of the plasticizing portion, it
is preferred that it be used in combination with liquid plasticizers such as
chlorinated paraffins which aid in imparting desired ~iscosity to the lmcured
mixture and improved elongation and adhesion to the cured composition. The
addition of polybutenes to a plasticizing portion comprising coal tar and
chlorinated paraffins generally results in improved hydrophobic properties of
the composition. Although chlorinated paraffins can comprise 100 wt. % of the
plasticizing portion, their use thereof generally imparts only moderately
improved hydrophobic properties to the cured composition and can tend to leave
it tacky. The use of chlorinated paraffins in combination with normally solid
resinous materials such as asphalt and coal tar results in a cured composi-
tion having an excellent combination of properties. Ln general~ asphalt
should comprise no more than about 90 wt. % of the plasticizing portion, and
it is desirably used in combination with chlorinated paraffins or phthalates.
The further addition of polybutenes to such compos-itions to counter-balance
the chlorinated paraffins improves the hydrophobic properties of the cured
compositlon. ~i
In addltion to the aforementioned tes;ts used to evaluate properties
of the cured composltlons, other tèsts have also been used. ~or example3 the
cured compositions hc~ve been evaluated under UV exposure and for wet and dry
adhesion and adhesion retention to glass.
In summary, it can be said that the present invention provides the
means for the formulation and use o$ relatively low cost compositions which
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, : ~ - - . . , : . .
, . . :,
.:- , - ~ . , ~ :
have an excellent combination of propert~es o-E the type required Eor insulat-
ed glass sealants.
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