Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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This invention concerns thermosetting resins containing
stoichiometric amounts of cement.
The production of phenolic moldings is an old art, having
involved, over the years, the use of two different types of
phenol-formaldehyde condensate: novolacs and resoles. The novo-
lacs were produced by condensing formaldehyde and phenol in a
mole ratio of about 1:1 or slightly less, and usually in the pre-
sence of an acidic condensing agent. Condensation was carried -
essentially to completion, so that the novolac became water in-
soluble and could be separated from associated water and used to
formulate a molding compound by mixing with a curing agent, usu-
ally hexamethylenetetraamine,and other additives such as fillers,
reinforcements, and mold release agents. Moldings were then pro-
duced in matched molds by the "heat pressure" method disclosed in
an early Baekeland patent.
Moldings have also been made by a casting technique from
resoles: partial condensates of formaldehyde and phenol in a
higher mole ratio, usually at least about 1.5:1; condensation is
caused by heating, usually in the presence of a fixed alkali con-
densing agent. Condensation is interrupted at a desired endpoint by discontinuing heating and acidifying to a desired pH at
which room temperature condensation i5 comparatively slow. The
casting can then be produced from the partial condensate by add-
ing a "hardener", e.g., a solution of hydrochloric or phosphoric ~ -
acid in glycerine or in a glycol, and pouring the resulting com-
position into a mold. Cure proceeds at ambient or a slightly
higher temperature. A detailed discussion of phenol-formaldehyde
condensates appears in The Chemistry of PhenoZic Resins, Martin,
published by John Wiley & Sons, Inc. in 1956, and the literature
references cited therein.
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The prior art (for example, U.S. Patent 3,502,610, Thomp-
son, issued March 24, 1970) also suggests that laminates, coat-
ings, moldings, and expanded foams can be produced from a poly-
hydric phenol-aldehyde resin containing 2-6 percent hydraulic
cement, based on the weight of the polyhydric phenol. The cement
is said to lower the viscosity of the resin, and to give it high
temperature strength and fire-retarding properties.
This invention concerns thermosetting resins containing
stoichiometric amounts of cement. The resin can be produced
prior to admixture with the cement, or the cement may be mixed
with the monomers prior to production of the resin. Stoichiome-
tric amounts as used in this application means that sufficient
cement is present to react with all water initially present in
the system plus any water of reaction formed during the cure of
the system.
According to this invention, a molding composition com-
prises (A) a mixture of (1) a thermosetting resin of at least one
of the phenol-forma:Ldehyde condensates, phenol-aminoplast-formal-
dehyde condensates, aminoplast-formaldehyde condensates, resor-
cinol-formaldehyde condensates, or resorcinol-formadehyde-urea
,
condensates and (2) cement, wherein the cement is present in an
amount within the range of from about 1 to about 20 parts by
weight of cement per part by weight of the water content of the
thermosetting resin; or (B) a condensate resin formed from cement,
formaldehyde, and at least one of phenol, aminoplasts or resorci-
nol, wherein the weight of the cement is from one to twenty parts
by weight of cement per part by weight of the water used to form
the resin and three-fifths of the weight of the formaldehyde used
to form the resin. Preferably, the amount of cement is from 1 to
9 parts by weight of cement per part by weight of the water, and
~ 2
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108V38o
the weight ratio of thermosetting resin to cement ranges from 1:1
to 1:4. The composition optionally may include an organo-silane
or amino-alkylsilane coupling agent and a clay, and also other
known fillers and mold release agents.
In one embodiment, the resin is produced prior to admix-
ture with cement. Hereinafter we will refer to this embodiment
as a "resin system". In another development, the cement is mixed
with the monomers prior to the production of the resin. Herein-
after, we will refer to that embodiment as a "monomer system".
Both of these systems produce compounds having excellent fire
resistance, low smoke-producing properties, and physical proper-
ties comparable to conventional phenolic molding compounds.
Another feature of the invention concerns the improvement
of the strength properties of these molding systems by the addi-
tion to the molding compounds of coupling agents of at least one
of (a) an organo silane containing at least two hydrolyzable si-
lane groups wherein the distance between any two hydrolysis sites
on a glass fiber is greater than the distance between any two
hydrolyzable silane groups in the organo silane, or (b) an amino-
alkylsilane.
Yet another feature of the invention concerns improvement -
in the mold flow properties and reduced surface bleeding of these
systems through the provision of a composite resin, cement, and
clay.
The thermosetting resin can be a phenol-formaldehyde con-
densate, a phenol-aminoplast-formaldehyde condensate, an amino-
plast-formaldehyde condensate, a furfural condensate, a furfuryl
alcohol condensate, a resorcinol-formaldehyde condensate, or a
resorcinol-formaldehyde-urea condensate. As a
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108V380
substitute for the phenol derivative in
the thermosetting resin, any suitable polyhydroxy aromatic com-
pound such as resorcinol can be employed. It also has been found
(see the examples) that the inclusion of urea can be advantageous
because of (a) the moderating effect the urea has on the reaction
rates, and (b) because urea acts as a fire retardant.
The mole ratio of formaldehyde to phenol can be varied
within wide limits in producing the resins for this inventions.
Indeed, in one sense, there is no upper limit on this ratio be-
cause Portland cement has been found to cure formaldehyde to aninfusible condition. As a practical matter, the mole ratio of
formaldehyde to phenol should range from 1:1 to 5:1. Most de-
sirably, this ratio ranges from 1.5:1 to 3:1.
It has been found that the relative proportions in which
the hydraulic cement or cements, phenol and formaldehyde can be
used in practicing the instant invention can be varied within -
comparatively wide limits. In one series of experiments, where
the formaldehyde to phenol ratio was held constant at 3:1, it was
found that a curable, workable phenol-formaldehyde condensate
could be produced when the amount of Portland cement charged
varied from one to twenty parts by weight of cement per part by
weight of the water used to form the resin and three-fifths of
the weight of the formaldehyde used to form the resin. Prefer-
ably the weight of hydraulic cement is from about one-and-a-half
to about five times this sum.
The ratio by weight of the thermosetting resin to cement ~ -
ranges from 1:1 to 1:4.
The resins of this invention are well suited for use as
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molding compounds and especially well suited for use in a closed
mold. Setting or curing of the cement occurs by hydration. Set-
ting the large amount of cement in the resins of this invention
requires the presence of large amounts of water. During molding,
the cement will rid the molding compound of any water resulting
from condensation or curing. The same is not true of the resins
disclosed in U.S. Patent No. 3,502,610 (mentioned earlier) which
contain only small amounts of hydraulic cement. These resins can
only be used in open molds where the water can escape to the
atmosphere.
The molding compounds also have good flame resistance and
low smoke-producing properties. They can be used, for example, -
to form shingles, appliances such as bathtubs, and coatings.
Hydraulic cements are broadly defined as powder mixtures
made from silica, alumina, lime, iron oxide, and magnesia, which
harden when mixed with water. Hydraulic cements include port-
land, calcium-aluminate, magnesia, natural, masonry, pozzolan,
and slag cements. For the purpose of this application, the term ~-
"cement" will be understood to include all hydraulic cements and
all cement products. Cement products, as used herein, include
those construction materials in which the active or hardening
constituents are magnesium or calcium derivatives. Commonly used
cement products include lime products and gypsum products.
As indicated previously, this invention can be carried
out using either of two systems.
The two systems are the monomer system and the resin sys-
tem. In both systems the amount of cement added is within the
range of from about 1 to about 20 parts by weight of cement per
1 part by weight of the total water in each system.
In the monomer system, the resin is formed in contact
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lV~(~380
with cement. Depending upon the percent of water in the aldehyde-
water solution used, it may be necessary to either add additional
water or remove some of the water of reaction. The total water
in this system is adjusted to be within the range of from about
.15 to about 5 moles of total water per 1 mole of the aldehyde
in the system.
In the resin system, the resin is produced prior to its
admixture with cement. In this system, the total water is deter-
mined, water adjustment is made, and cement is added accordingly.
The addition or removal of water may or may not be necessary.
The total water in this system is determined as follows. A
sample of the resin is placed in an aluminum weighing dish and an
initial weight is recorded. The aluminum weighing dish and its
contents are then put in an over and dried at about 110C for a
period of about 3 hours. The aluminum weighing dish is removed
from the oven, allowed to cool to room temperature, and a final
weight recorded. The remaining resin is a cured solid mass.
Next, the percent solids of the resin is determined by dividing
the final weight by the initial weight. Assuming stoichiometric
proportions of all ingredients and substantially 100~ reaction,
water is assumed to comprise the total percentage of volatiles
tlOO -percent solids). There~ore, the percent volatiles multi-
plied by the initial weight of the resin gives the total water in
the resin system.
The molding compounds of this invention can contain 0.01
to 10.0 weight percent of the coupling agents based on the total
weight of the molding compounds. Preferably this amount ranges
from 0.01 to 5.0 weight percent.
With regard to the coupling agents, a particularly suit-
able aminoalkylsilane is gamma-aminopropyltriethoxysilane which
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is commercially available from Union Carbide under the product
designation "A-1100" and from General Electric under the product
designation "SC-3900". Also suitable is N-beta (aminoethyl)
gamma-aminopropyltrimethoxysilane commercially available from
Union Carbide under the product designation "A-1120" and from
Dow Corning under the product designation "Z-6020". -
The organo silane containing at least two hydrolyzable
silane groups having the formula:
(RO) 3 SiR'Si(OR) 3
wherein each R is an alkyl or aryl group containing from 1 to 10
carbons and R' is an alkylene or phenylene group containing from
1 to 15 carbons. A particularly suitable second silane coupling
agent is bis (B-trimethoxysilylethyl) benzene (CH30)3SiCH2CH2 ~ -
CH 2 CH 2 S i ( OCH 3 ) 3 ) .
A clay is a naturally-occurring sediment or sedimentary
rock composed of one or more minerals and accessory compounds,
the whole usually being rich in hydrated alumina or in iron
oxide, predominantly in particles of collodial or near-collodial
size, and commonly developing plasticity when sufficiently pul-
vèrized and wetted. Modern studies have organized the clay min-
erals into ~our crystalline groups and one noncrystalline group:
(1) the kaolin group, (2) the montmorillonite group, (3) the
variously named illite, bravasite, or hydromica group, (4) atta-
pulgite, and (5) allophane, which is the noncrystalline group.
The clays which can be utilized in this invention are of the
kaolin crystalline group. More specifically, kaolins which have
been employed are classified as ceramic clays. Ceramic clays
will be understood to include: residual kaolin clays, sedimen-
tary kaolin clays, ball clays, fire clays, and clays prepared for
porcelain enamels. Old Mine #4 Ball Clay, available from
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Kentucky-Tennessee Clay Co., located in Mayfield, Kentucky, is
particularly suited for use in this invention. Old Mine #4 Ball
Clay has a raw color of medium gray and a fired color, cone 12,
of light gray white. Typical chemical analysis data of Old Mine
#4 Ball Clay shows:
Ingredient Percen~ by Weight
Silicon Dioxide (SiO2) 52.1
Aluminum Dioxide (Al203) 31.1
Titanium Dioxide (Tio2) 1.6
Iron Oxide (Fe2O3) 0.8
Calcium Oxide (CaO) 0.4
Magnesium Oxide (MgO) 0.3
Potassium Oxide (K2O) 1.0
Sodium Oxide (Na2O) 0.3
Loss on Ignition 12.4 ~ -
Total 100.0 -
99% of the particles comprising Old Mine #4 Ball Clay are
finer than 20 microns, and 68% of the particles are finer than 1
micron.
The amount of ceramic clay which can be employed in a
molding compound of this invention is within the range of from
about 5 to about 40 percent by weight of the total weight of the
molding compound, clay included. Preferably, ceramic clay is
present in an amount within a range of from about 10 to about 20
percent by weight of the total weight of the molding compound. -
; The molding compounds of this invention can be molded by
any suitable molding method~ They are particularly suitable for
use as sheet molding compounds (SMC) or a bulk molding compound
(BMC). When so used, the molding compound is employed in an
amount from about 10 to about 95 percent by weight of the total
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108l~380
composition, reinforcing the glass fibers in an amount up to
about 80 percent by weight of the total composition, and fillers
in an amount to make up the balance of the total composition.
Preferred fillers are calcium carbonate and alumina.
In both SMC and BMC it is preferred that a mold release
agent be added in an amount up to about 5 percent by weight of
the sheet or bulk molding compound. A particularly suitable mold
release agent is zinc stearates.
The following examples illustrate the invention.
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EXAMPLE 1
IngredientsParts by Weight ~ol Ratio
Formaldehyde127.90 3.1
Phenol 67.10
Calcium Oxide3.78
Dicyandiamide3.35
Urea (liquid)20.06
The phenol and formaldehyde were charged to a --
reactor, blended and heated to a temperature of 110 F. The
calcium oxide catalyst then was added over a two-hour period
while maintaining the temperature at 110 F. The temperature
of the reactants was increased to 125F over a 30-minute
period and then maintained at that temperature for an additional
90 minutes. The temperature then was raised to 140F during a
time period of 30 minutes and maintained at that temperature
until the free formaldehyde content ranges from 7.0 to 7.2
percent by weight. The dicyandiamide was added over a 30-
minute period at 140 F and the reaction was cooled to 105F
over the next 1/2-hour period. The urea was added at 105F and
neutralization followed when the temperature dropped below
100F by addition of a mixture of 20 percent by weight of
phosphoric acid and 80 percent by weight of sulfuric acid to a
pH ranging from 7.2 to 7.3.
Physical properties of the Example I resin are as
follows:
Stroke Cure 77 seconds -
Free Phenol 1.2 percent
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lV~3~380
EXAMPLE I I
The followinq materials were mixed in a stainless
steel vessel:
Weight grams
Resin of Example I 5000
Portland Cement 2500
Gypsum Cement 2500
Alumina Trihydrate 2000
Zinc Stearate 20Q
The resulting composition was co-deposited with
chopped glass fiber strand on amoving polyester film approximately
24 inches in width and of indefinite length. A second polyester
film, also 24 inches in width and of indefinite length, was brought
into contact with the upper surface of the sheet-like mass of
deposited glass fibers and resin-cement mixture and was moved
with the mass and the first sheet. Sheets of the mass, approxi-
mately 24 inches by 20 inches by 1/8 inch, were cut from the mass,
leaving the polyester films on each of the two major sides
thereof. Moldings were produced from these sheets between matched
flat dies: five minutes at 300F and 2000 pounds per square
inch.
Sheets produced as described above were tested for
flexural modulus, for flexural strength, for tensile strength,
and for notched Izod impact strength: (1) as molded, and
(2) after they had been autoclaved for 16 hours. Results of
this testing are summarized in the following Table.
In the Examples, flexural strength and flexural
modulus were determined according to ASTM Specification D79n,
tensile strength was determined according to AsTrq Specification
D638, and impact strength was determined according to ASTM
Specification D256.
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V380
TABLE
Flexural Flexural Tensile ~lotched Izod
Strength Modulus Stren~th Impact Strength
psi x 103 psi x 106 psi x 103 ft., lbs./in.
As molded ll.99 1.107 4.37 8.92
After 16 hours
of autoclaving7.65 0.759 2.41 6.5
These results demonstrate that the thermosetting
resins of this invention possess physical properties which make
them ~ery desirable for use as molding compounds. The molded
articles were found to be fire resistant and low smoke producing.
They were easily cured in a closed mold.
EXA~PLE III
':
A phenol-urea-formaldehyde condensate was produced
from 1240 parts phenol, 2600 parts 52 percent formaldehyde,
2500 parts Portland cement, 1290 parts urea, 2500 parts gypsum
cement, 2500 parts alumina, 400 parts zinc stearate and 800
parts ice. The phenol, formaldehyde, urea and 100 parts of the
Portland cement were charged to a stainless steel vessel
equipped with a propeller type agitator and an indirect heat
exchanger. This charge was agitated for 18 hours, during which
time cooling water was circulated through the indirect heat
exchanger to maintain the temperature of the charge at about
68C. After the preliminary 18 hour reaction period, the
rest of the Portland cement, the gypsum, the alumina, the
zinc stearate and the ice were added to the reactant products
in the vessel. The resulting composition, which was 2 phenol~
formaldehyde condensate was co-deposited with chopped glass
fiber strand (The fibers were made of a glass containing about
54 percent SiO2, 14 percent A1203, 4.5 percent MgO, 17.5
percent CaO and 10 percent B203. They were coated with a
polyester size containing a lubricant and gammaaminopropyl-
triethoxysilane.) on a moving polyester film approximately 24
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V
inches in width and of indefinite length. A second polyester
film, also 24 inches in width and of indefinite length was
brought into contact with the upper surface of the sheet-like
mass of deposited glass fibers and phenokformalde~yde condensate,
and was~moved Withthe mass and the first sheet. Sheets called
"Sheet Molding Compound", of the mass of condensate and glass
fibers approximately 24 inches by 20 inches by 1/8 inch were
cut from the mass, leaving the polyester films on each of the
two major sides thereof. Moldings were produced from these
sheets between matched flat dies: five minutes at 300F. and
283 pounds per square inch.
Sheets produced as described above were tested for fleYural
modulus, ~ST~: n-790) for flexural strength, for tensile stren~th,
(ASTM D-638) and for notched Izod impact strength:(ASTM D-256)
(1) as molded; (2) after they had been autoclaved for 16 hours
at 227F.; and (3) after they had been immersed in boiling water
for two hours. Results of this testing are summarized in the
following Table for several ratios of glass fibers to phenol-
formaldehyde condensate.
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It has heen found that the phenolic condensate
produced as descri~ed ahove has a shelf life sufficiently long, ~ -
under ordinary ambient conditions, that Sheet ~olding Compound
produced therefrom within four hours is satisfactory, and the
sheet molding compound, itself, has a shelf life greater than
three weeks. It will be appreciated that this is adequately
long to make ordinary use of the material for producing sheets
or other moldings entirely feasible.
The data in the foregoing Table show an unexpected
result: a comparatively slight decrease in the strength of
the moldings, as indicated by the data, after two hours of
autoclaving at 227F. and after two hours in boiling water,
indicates that the glass fibers were not appreciably affected
by the cement. This is unexpected because glass fibers of the
indicated composition, distributed in reinforcinq relationship -
with a hydrated mixture of equal parts of Portland and C.ypsum
cements, would be at least virtually destroyed by sixteen hours
of autoclaving at 227F. The data in the foregoing Table, on
the other hand, indicate not more than slight deterioration of -
the fibers during either autoclaving or boiling. -
To demonstrate the excellent fire resistance of
moldings produced according to the method of Example III, panels
were produced and were tested forflame spread, fuel con-
tributed and smoke developed in comparison with panels which
presently are being produced commercially. The panels according
to the invention were produced from a phenol-urea-formaldehyde
condensate produced as described in Example III, above, from
the charge there set forth plus 20 parts 1,2-bis-trimethoxysilyl-
~thane. Sheets were produced as described in Example IV from the
resulting condensate and glass fibers (The glass fibers were made
i~ - 16 -
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of a glass havin~ the composition set forth in Example 1 above,
and coated with a polyester size containing gammamethacryloxy-
propyltrimethoxysilane.) codeposited with the condensate in
such proportions that the glass fibers constituted suhstantially
22 percent of the condensate and fibers. Panels 21 inches by
24 inches by 1/8 inch were then molded from the resulting sheets:
290 F for 5 minutes at 60 tons pressure. These panels were
tested, ASTM E-84 tunnel test against panels which are presently
being marketed, with the following results:
Panels Produced Present
According to Commercial
the Invention Panels
Flame Spread 20 90 to 110
Fuel Contributed 0 25 to 50
Smoke Developed 2 400 to 500
In each case, a low number for the E-84 tunnel test
indicates better performance than does a higher number.
EXAMPLE IV
This example demonstrates the monomer system in
which was employed a com~ination of cements. he following
ingredients were employed.
Ingredients Weight, grams ~ole Ratio
Phenol 94
52% Formaldehyde
Solution in Water 144.2 2.5
Portland Cement 171.3
Gypsum Cement 171.3
Deionized Water 45
The ingredients can be mixed in any order and by any
suitable mixing procedure. However, it is preferred to add the
cements in two steps to enable the resulting exothermic reaction
to be controlled thus avoiding immediate set-up of the cem~nts.
~ - 17 -
:lO~V~o
In this example, 94 grams of phenol, 144.2 grams o a
52% solution of formaldehyde in water, 45 grams of water, and 10
grams of ~o~tland cement were added to a beaker at room temperature.
The mixture was stirred and the exothermic reaction proceeded
immediately.
The beaker was water-cooled to prevent heating to a
temperature over 60 C. The mixture was permitted to cool to room
temperature at which time the remaining 161.3 grams of Portland
cement and 171.3 grams of gypsum cement were added to the beaker
with stirring. The resulting product was recovered as a molding
compound. The gypsum cement used was commercially available from
United States Gypsum under the trade name "Hydracal B-ll".
EXAMPLE V
.
8.7 grams of gamma-aminopropyltriethoxysilane were ---
added to 580.8 grams of the monomer system of Example I. The
addition was made at room temperature in a beaker with stirring.
The resulting product was recovered as a molding compound.
The gamma-aminopropyltriethoxysilane was "~-1100" available from
Union Carbide.
EXAMPLE VI
8.7 grams of bis(B-trimethoxysilylethyl) benzene, a
silane coupling agent with two hydrolyzable silane groups, were -
added to 580.8 grams of the monomer system of Example I. The
addition was made at room temperature in a beaker with stirring.
The resulting product was recovered as a molding compound.
EXAMPLE VII
4.35 grams of gamma-aminopropyltriethoxysilane and
4.35 grams of bis(B-trimethoxysilylethyl)benzene, a silane
coupling agent with two hydrolyzable silane groups, were added
to 580.8 grams of the monomer system of Example I. The
addition was made at room temperature in a beaker with stirring. -
The resulting product was recovered as a molding compound. The
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3t~0
gamma-aminopropyltriethoxysilane was "A-llO0" available from
Union Carbide.
EXAMPLE VIII
5000 grams of the resin of Example I, 2500 grams of
Portland cement, and 2500 grams of gypsum cement were added to
a stainless steel vessel at room temperature with stirringO The
resulting product was recovered as a molding compound.
EXAMPLE IX
5.25 grams of gamma-aminopropyltriethoxysilane were
added to 350 grams of the resin system of ~xample YI. The
addition was made at room temperature in a beak.er with stirring.
The resulting product was recovered as a molding compound. The
gamma-aminopropyltriethoxysilane was "A-llO0" available from
Union Carbide.
EXA~PLE X
5.25 grams of bis(B-trimethoxysilylethyl)benzene,
a silane coupling agent with two hydrolyzable silane groups,
were added to 350 grams of the resin system of Example VI. The
addition was made at room temperature in a beaker with stirring.
The resulting product was recovered as a molding compound.
EXAMPLE XI
2.62 grams of gamma-aminopropyltriethoxysilane and
2.62 grams of bis(B-trimethoxysilylethyl)benzene were added to
350 grams of the resin system of Example VI. The addition was ~-
made at room temperature in a beaker with stirring. ~he ~ -
resulting product was recovered as a molding compound.
EX~MPLE XII
This example will demonstrate the incorporation of
a resin system into sheet molding compound (SMC). The following
ingredients were employed.
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INGREDIENTSWEIGHT, Gl~AMS
Resin of Example VI10,000
gamma-aminopropyltrieth-
oxysilane 10
bis(B-trimethoxysilyl-
ethyl)benzene 10
Alumina 2,000
Zinc Stearate 200
The above ingredients can be mixed in any order and
by any suitable mixing procedure. However, in this example,
they were mixed as follows. The resin was first charged to
a stainless steel mixing vessel at room temperature. The
gamma-aminopropyltriethoxy silane and the bis ~ -trimethoxy-
silylethyl)benzene were added next with stirring. While the
stirring was continued and room temperature maintained, the
alumina was added followed by the zinc stearate.
The resulting composition was co-deposited with
chopped glass fiber strand on a moving polyethylene film
approximately 24 inches in width and of indefinite length. A
second polyethylene film also 24 inches in width and of
indefinite length, ~as brought into contact with the upper
surface of the sheet-like mass of deposited glass fibers and
resin-cement mixture and was moved with the mass and the first ~:
sheet. Sheets of the mass, approximately 24 inches by 20 inches
by 1/8 inch, were cut from the mass, leaving the polyethylene
films on each of the two major sides thereof. ~oldings were - -
produced from these sheets between matched flat dies, moldings
being conducted for five minutes at 300F and 1000 pounds per -
square inch. ~ -
Sheets produced as described above were tested for
flexural modulus, for flexural strength, for tensile strength, ~-
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~v~o
and for notched Izod impact strength, both (1) as molded, and
(2) after the sheets had been autoclaved for 16 hours at a
temperature of 227 F. Results of this testing are summarized
in the following Table and are compared to a control in which
the sheets were produced from a molding compound which employed
the same resin system without coupling agent.
TABLE
ControlEXAMPLE XII
Flexural Strength, psi x 10
(as molded) 11.99 19.43
10 Flexural Strength, psi x 103
(after 16 hours of autoclaving) 7.65 10.95
Flexural Modulus, psi x 106
(as molded) 1.107 1.706
Flexural Modulus, psi x 106
(after 16 hours of autoclaving) 0.759 1.309
Tensile Strength, psi x 103
(as molded) 4.37 7.75
Tensile Strength, psi x 103
(after 16 hours of autoclaving) 2.41 4.37
Notched Izod Impact Strength
Foot/Pounds/Inch
(as molded) 8.92 7.20
In the examples, flexural strength and flexural
modulus were determined according to ASTM Specification D790,
tensile strength was determined according to ASTM Specification
D638, and impact strength was determined according to ASTM
Specification D256.
These results demonstrate that the molding compounds
of this invention possess physical properties which make them
very desirable for use as molding compounds. The molded
articles were found to be fire resistant, to be low smoke
producing, and to have improved strength. In addition, the
molded articles were easily cured in a closed mold.
.i r . 21
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l~V3~0
EXAMPLE XIII
This example demonstrates a preferred mode of preparing
a molding compound of this invention and its incorporation into
sheet molding compound (SMC). The following ingredients were
employed:
Parts by Weight
Ingredients per 100 parts
Resin of Example I 35.2
Portland Cement 17.6
Gypsum Cement 17.6
Ceramic Clay 14.0
Glass Fibers 14.0
Zinc Stearate 1.4
gamma-aminopropyltriethoxysilane .1
tetraethoxysilane .1
The above ingredients can be mixed in any order and
by any suitable mixing procedure. However, in this example,
they were mixed as follows. The resin was first charged to a
stainless steel mixing vessel at room temperature. Next, the
total amount of portland cement, and the total amount of gypsum
cement, was added sequentially at room temperature with stirring.
While stirring was continued and room temperature maintained,
the ceramic clay and the zinc stearate were added followed by
the two coupling agents. The product was recovered as a molding -
compound. The ceramic clay used was Old Mine #4 Ball Clay. The
gypsum cement used was Hydracal B-ll commercially available
from United States Gypsum Corp. The gamma-aminopropyltri-
ethoxysilane used was A-1100 and the tetraethoxysilane used
was Tetraethyl Orthosilicate, both commercially available from
Union Carbide Corporation.
The ingredients were deposited on a moving
,,
~ - 22 -
10~ 0
polyethylene film approximately 24 inches in width and of
indefinite length. A second polyethylene film also 24 inches
in width and of indefinite length, was brought into contact
with the upper surface of the sheet-like mass of deposited
glass fibers and resin-cement mixture and was moved with the
mass and the first sheet. Sheets of the mass, approximately
12 inches by 18 inches by 1/8 inch, were cut from the mass,
leaving the polyethylene films on each of the two major sides
thereof. Moldings were produced from these sheets between
matched flat dies, moldings being conducted for three minutes
at 300F and 926 pounds per square inch. In the resulting
molded article we noticed very little surface bleeding.
EXAMPLE XIV
This example demonstrates a method of preparing a
molding compound of the invention. The following ingredients
were used: -
Parts by Weight
Ingredients per 100 parts
Resin of Example I 35.2
Portland Cement 17.6
Gypsum Cement 17.6
Ceramic Clay 14.0
Glass Fibers 14.0
Zinc Stearate 1.4
gamma-aminopropyltriethoxysilane 0.1
tetraethoxysilane 0~1 -
The above ingredients were mixed using the same
mixing procedure as in Example XIII. The glass fibers were
added with continued stirring at room temperature after the
addition of the silane coupling agents. The stirring was
continued until the glass fibers were evenly dispersed.
~ - 23 -
o
The resulting compound was recoYered as a bulk molding
compound (BMC). The individual glass fibers used had a
length within the range of from about 1/8" to about 1 1/4"
and a diameter within the range of from about .00025" to
about .000299". The ceramic clay used was Old Mine ~4 Ball
Clay. The gypsum cement used was Hydracal B-ll. The gamma-
aminopropyltriethoxysilane used was A-1100 and the tetra-
ethoxysilane was Tetraethyl Orthosilicate.
A charge of the resulting compound weighing about
1000 grams was placed into a heated mold. A flat sheet
molding, approximately 12 inches by 18 inches by 1/8 inch
was produced between matched flat dies. The molding was -
conducted for three minutes at 300F and at a pressure of
926 pounds per square inch. -
In the resulting molded article was observed good ~ -
mold flow and very little surface bleeding.
EXAMPLE XV
The following example demonstrates the use of the
monomer system to prepare a molding compound of ~he invention.
In this example the thermosetting resin is produced in contact
with cement to form a resin-cement molding compound. The
resulting resin-cement molding compound is then further
modified and incorporated into sheet molding compound(SMC).
The following ingredients are employed.
Parts by Weight Mole
Ingredients per 100 parts Ratio
Phenol 9.5
52% Formaldehyde
Solution in Water 14.6 2.5
Portland Cement 17.2
Gypsum Cement 17.2
~ - 24 -
Deionized Water 4.5
Glass Fibers 23.0
Ceramic Clay 12.6
Zinc Stearate 1.2
gamma-aminopropyl-
triethoxysilane .1
tetraethoxysilane .1
The ingredients can be mixed in any order and by any
suitable mixing procedure. However, it is preferred to add
the cements in two steps to enable the resulting exothermic
reaction to be controlled thus avoiding immediate set-up of
the cements.
In this example, the total amounts of phenol 52%
formaldehyde-water solution, and deionized water are first
charged to a stainless steel mixing vessel at room temperature.
Approximately 10~ of the total amount of portland cement is
then added. The mixture is stirred and the exothermic
reaction proceeds immediately.
The mixing vessel is then water-cooled to prevent
heating to a temperature over 50C. The mixture is permitted
20 to cool to room temperature at which time the remaining ~ -~
amount of portland cement, the total amount of gypsum cement,
the total amount of gamma-aminopropyltriethoxysilane, and
the total amount of tetraethoxysilane are added to the vessel
with stirring. The resulting product is a resin-cement
molding compound.
While stirring is continued, the above resin-cement
molding compound is modified by the addition of the total
amounts of ceramic clay and ~inc stearate. The ceramic clay
used is Old Mine #4 Ball Clay.
The ingredients are deposited on a moving poly-
~ - 25 -
,
V~V
ehtylene film approximately 24 inches in width and of
indefinite length. A second polyethylene film also 24 inches
in width and of indefinite lenqth, is brought into contact
with the upper surface of the sheet-like mass of deposited
glass fibers and resin-cement compound and is moved with the
mass and the first sheet. -~
The resulting product is recovered as sheet molding
compound (SMC).
EXAMPLE XVI (Control)
In this example the same ingredients were used as in
Example XIII except that alumina was used as a filler instead
of ceramic clay. The mixing procedure was the same as in
Example II and the resulting molding compound was incorporated
into SMC in the same manner as in Example XIII. In the
resulting molded articles was observed noticeable surface
bleeding in comparison with moldings of Example XIII in which
wasobserved very little surface bleeding.
EXAMPLE XVII (Control)
. .
In this example the same ingredients were used as
in Example XIV, except that alumina was used as a filler
instead of ceramic clay. The mixing procedure was the same
in Example XIV and the resulting bulk molding compound was
molded in the same manner as in Example XIV. In the resulting
molded article was observed poorer mold flow and noticeable
surface bleeding in comparison to moldings of Example XIV in
which was observed good mold flow and very little surface
bleeding.
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