Note: Descriptions are shown in the official language in which they were submitted.
~L096524
Glass fibers which are to be used as a reinforcement
for thermoplastic and/or thermosetting resins are made by pulling
molten streams of glass until they solidify into filaments,
grouping the filaments together into a strand, and coiling the
strand into a package on a revolving mandrel. Glass fibers
scratch easily and thereafter break when they are pulled and
bent over guide surfaces. To avoid ~reaking, the prior art has
always coated ~he filaments immediately after solidification and
before the fibers are drawn together into a strand with a water
solution of a film former and a lubricant. The lubricant
provides lubricity in the wet condition between the filaments,
and between the strand and guide surfaces over which the strand
is drawn. Heretofore, a combination of a cationic lubricant
and a nonionic lubricant has usually been used because the
cationic would not provide proper lubrication after the strand
was dried, and the nonionic lubricant would not provide lubrica-
tion when the strand was wet. In addition, heretofore, the
lubricants which have been used have interfered with the bonding
between the film forming polymers and the glass fibers.
Additionally, the lubricants have also interfared with the
bonding of the strand to the matrix resin which the strand was
used to reinforce. Heretofore, therefore, the lubricants which
have been used have been a necessary evii, and in all instances
with which I am familiar, they have decreased the strength of
the reinforced polymers which have been made. This has been
determined by producing the strands with various amounts of the
lubricants, and plotting the strength of the resulting laminates.
The decrease in the strength of the resulting lamina~e has
usually been more than could be accounted for by reason of the
broken filaments alone.
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According to one aspect of the invention an aqueous
size composition for coating glass fibers for reinforcing a
nylon polymer comprises the following solids in parts by weight:
Emulsified particles of 5.0 - 12.0
an epoxy film former
Polyurethane : 0,5 - 7.0
Silane glass coupling agent Q.l - 5.0
Cationic lubricant 0.1 - S.0
wherein said cationic lubricant is the reaction product of a
fatty acid and a secondary amine having two organo side chains
each of which have a carbon to oxygen ratio of no more than 4
to 1 and each of which includes at least one OH group.
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According to a further aspect of the lnvention there
is provided a glass fiber reinforced plastic article wherein
the glass fibers have a coatiny of the following solids in ~he
following parts by weight:
Emulsified particles of an epoxy
film former 5.0 to 12
Polyurethane 0.5 to 7
Silane glass coupling agent 0.1 to 5
Cationic lubrican 0.1 to 5
wherein said cationic lubricant is the reaction product of a
fatty acid and a secondary amine having two organo side chains
each of which have a carbon to oxygen ratio of no more than 4
to 1 and each of which includes at least one OH group.
:~ A principal object of the present invention, therefore,
is the provision of a new and improved size containing a material
which will not only protect and lubricate the glass fibers during
the wet condition, but will also protect the fibers in the dried
condition without decreasing the strength of the resulting re-
inforced polymers produced therewith; and which hopefully in-
creases the strength of the resulting reinforced polymeric
materials.
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Thermoplastic polymers are the most difficult to rein-
force because of their lack of chemical functionality. The pre-
ferred size for glass fibers comprises a thermoplastic polymer
and a lubricant which adequately lubricates glass fibers during
their wet and dried conditions, and which also aids in the bond-
ing of the thermoplastic polymer to the glass fibers.
Further features and advantages will become apparent
to those skille~l in lhe art from khe following description of the
preferred e~odiments.
DESCRIPTION OF T~E PREFERRED EMBODIMENTS
EXAMPLE 1
A size was made from -the following materials in the parts
by weight given below:
Materials Parts by Weight
-
FSE-l epoxy emulsion (55% solids) 12.7
Wyandotte X1042* polyurethane 1.0
latex (50% solids)
Gamma-aminopropyltri.methoxysilane 1.4
Glass lubricant - reaction product 1.0
of diethanolamine and stearic acid
Deionized water 83.9
The si~e was prepared by adding the gamma-aminopropyltrimethoxy-
silane to half of the water under agitation until hydrolyzed,
and the urethane latex was then added with agitation until
thoroughly mixed. Thereafter the epoxy emulsion is added and
thoroughly mixed for 5 minutes. In another mixing tank the
glass l~bricant is adde~d to 30 parts by weight of water a~ 120F.
* A regi~ter~d Trade Mark
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and is mixed until dissolved. This glass lubricant solution
is then added to the main mix and agitated until a homogeneous
dispersion is achieved, and the balance of the water is then
added.
The above size was applied to 816 E-ylass fibers having
a diameter of between .00035 and .00060 inch at forming using
a belt type applicator and the wetted strand is coiled into a
package at 3800 FPM and dried for 24 hours in a heated oven at
265F. The fibers so produced have a coating thereon which
comprises approximately 0.5% by weight of the coated strand~
The coated strands are chopped into approximately ~ inch lengths.
Thirty parts of these coated short fibers-are then placed in a
drum tumbler with 70 parts of Nylon 66 having a melting index of
2.0 and a molecular weight of approximately lO0,000. This
mixture is then placed in a l-inch National Rubber machine screw
extruder which is electrically heated to 540F. and the mixture
is extruded into 1/8 inch diameter cylindrical rods which are
then fed into a Cumberland pelletizer to form ~ inch long
pellets. The pellets are in turn fed to an injection molding
machine heated to 550F. and the material is injected into a
standard ASTM D-633 dogbone test specimen, which when cooled at
room temperature and tested in a standard tensile testing
machine broke when a force equal to 25,000 psi was applied to
the specimen. The material also has a modulus of elasticity
of 1.2 x loS.
- By way of comparison, and not according to the
invention, glass fibers were coated with a prior art size of
the following composition:
Materials Parts by Weight
PV Acetate (55% solids) 13.0
Gamma-aminopropyltrimethoxysilane 1.4
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Polyoxyethylene-monooleate 1.0
Fibers coated with this material, using the same procedure of
Example 1, give tensile strengths of only 20,000 psi at the same
fiber loading given above. This polyvinyl acetate size is
selected for comparison because polyvinyl acetate is known to
have good wetting and coupling properties to the surface of
glass fibers and has long been an accepted standard.
EXAMPLE 2
The process of Example 1 was repeated using the size
formulation of Example 1 excepting that no glass lubricant was
used, and the fibers were formed at a reduced speed of 2,000 FPM
and with great care. The resulting test specimen had a strength
of only 22,000 psi, and the strand did not have sufficient
lubricating properties that it could be made on a commercial
basis.
EXAMPLE 3
The process of Example 1 was xepeated excepting that
the amount of the glass lubricant was decreased to 0.5 parts by
weight~ mhe resulting test specimen had a strength of 24,500
psi.
EXAMPLE 4
The process of Example 1 was repeated excepting that
the polyurethane emulsion was deleted. The test specimen so
produced had substantially the same strength as did the test
specimen of Example 1.
EXAMPLE 5
The process of Example 1 was repeated excepting that
the amount of the glass lubricant was increased to 2%. The
test specimen so produced had a strength of 24,500 psi.
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EXAMPLE 6
` The process of Example 1 was repeated excepting that
n-beta-(aminoethyl)gamma-aminopropyltrimethoxysilane was
substituted for the gamma-aminopropyltrimethoxysilane coupling
agent. The test specimen so produced had a strength of
approximately 25,000 psi.
EXAMPLF 7
The process of Example 1 was repeated excepting that
a forming size of the following composi~ion was used:
Materials Parts by Weight
Water soluble epoxy of the 2.0
formula given-below
FSE-l epoxy emulsion (55% solids) 13.0
Gamma-aminopropyltrimethoxysilane 1.0
glass coupling agent
Deionized water 90.0
The water soluble epoxy had the following formula: ' -
H-CH2-CH2~ ~ ~3 OH
N-CH2-CH-CH2-----~-CH2-CH-CH2 _
; -O ~ -O-~H2-CH-C I2 ~ CH2-CH2 ~ O-C-(CH2) -CH=C~-
CH3
20 ~CH2)7 CH3
The size was produced by adding the soluble epoxy to ~ of the
water with sufficient acetic acid to solubilize the material.
The glass coupling agent was added thereto and thoroughly mixed.
; Thereafter the epoxy emulsion was added and thoroughly mixed for
5 minutes. In another mixing tank, the glass lubricant was
added to 30 parts by weight of water at 126F. and mixed until
dissolvea. The glass lubricant solution was then added to the
main mix and agitated until a homogeneous dispersion was achieved,
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following which the balance o~ the water was added.
The above size was applied to the glass fibers using
the procedure of Example 1 excepting that the fibers were formed
at 2,200 feet per minute and were dried for 24 hours in a heated
oven at 265F. The fibers so produced have a coating thereon
which comprises approximately 1.0% by weight of the coated
strand. The coated strand was chopped into approximately 1/8th
inch lengths. These fibers when tested in the manner described
in Example 1 above provided a test specimen having a strength
of 25,000 psi in the Nylon 66 matrix.
By way of comparison, and not according to the
invention, the above procedure was repeated excepting that the
glass lubricant was deleted, and the test specimen so prepared
had a strength of approximately 21,000 psi~
S ExAMæLE 8
The process of Example 7 was repeated excepting that
the glass coupling ag~nt was deleted, and the test specimen so
prepared had a strengkh of approximately 20,000 psi.
EXAMPLE 9
The process of Example 7 was repeated excepting that
the matrix resin used in the production of the dogbone samples
was a Nylon 612 having a M.W. of 150,000 instead of Nylon 66.
These test specimens have a strength of 27,000 psi.
EXAMPLE 10
The process of Example 1 is repeated excepting that a
polycarbonate having a molecular weight of 150,000 and a melting
index of 2 is used in place of the Nylon 66 matrix polymer. In
addition, the extruder was operated at a temperature of 570F.
and the molding machine was operated at a temperature of 580F.
The amount of chopped glass fibers used-was only 20% of the
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polycarbonate glass fiber mixture, and the tensile strength of
the test specimen was d~termined to be 17,000 psi. By way of
comparison, and not according to the present invention, test
specimens similarly produced excepting that the glass fibers
contained a prior art polyvinyl acetate size have a s-trength
of only 14,000 psi.
EXAMPLE 11
The process of Example 1 is repeated excepting that
polybutyleneglycol-terephthalate polyester having a molecular
weight of 180,000 and a melting index of 3, made by reacting
1 mole of polybutyleneglycol with one mole of terephthalic acid
was substituted for the Nylon 66, and an extrusion temperature
of 480F. and a molding temperature of 490F. was used. The
test specimen so produced had a tensile strength of 19,000 psi
whereas the same material reinforced by glass fibers using a
prior art polyvinyl acetate size only has a tensile strength
of 13,000 psi.
EXAMP~E 12
Ninety-nine and one half parts of the Nylon 66 used in
Example 1 is mixed with 0.5 parts of the reaction product of
diethanolamine and stearic acid, as a mold release agent. Dogbone
samples are made using the same procedure given in Example 1 and
these samples are easily removed from the mold and have a
strength as good as or slightly better than do samples of
- specimens made from the Nylon 66 by itself. It is clear that
any reaction product of a fatty acid and a secondary amine having
two organo side chains each of ~7hich have a carbon to oxygen ratio
of no more than 4:1, and each~of which includes at least one OH
group, operate as mold release agents for thermoplastic polymers,
and ~7hen so used will be effective in amounts of from 0.1% to
2% of the molding compound.
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EXAMPLE 13
The process of Example 7 was repeated excepting that
an emulsion of a polyester was used in place of the epoxy film
formers of Example 7. The polyester was made by reacting 1
mole of ortho-phthalic acid and 1 mole of succinic acid, and 2.4
moles of propylene glycol to an acid number of 30 to 35. An
emulsion was made of the following materials in percent by
weight:
Materials Percent by ~eight
10 Polyester described above 47,5
Xylene 5.3
Diacetone alcohol 10.6
Wyandotte Chem. Co. Pluronic L101 * 2.
Wyandotte Chem. Co. Pluronic P105 7.8
Water 26.2
An emulsion was prepared by diluting the polyester with the
xyleneO The Pluronics were dissolved in the diacetone alcohol
and the solution was added to the polyester solution. Water
was then added slowly with agitation until the inversion point
was reached~ following which the balance of the water was added
and thoroughly mixed. The polyester emulsion so produced when
substituted for the epoxy materials yave substantially the same
results as did the materials of Example 7.
EXAMPLE 14
The process of Example 1 is repeated excepting that
1.25% of the reaction product of butyl ethyl, 2,2'dihydroxy-
amine and oleic acid is substituted for the lubricant of
Example 1 and the test specimen has substantially the same
properties.
*A Registered Trade Mark
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EXAMPLE 15
The process of Example 14 is repeated excepting that
the lubricant is the reaction product of butyl ethyl, 3,2' ~
dihydroxy-amine and pelargonic acid, and the test specimen has
substantially the same strength as that of ~xample 1.
EXAMPLE 16
The process of Example 1 is repeated excepting that
the lubricant is the reaction product of di-2-hydrindyl, 1,1' -
dihydroxy-amine and stearic acid, and the test specimen has
substantially the same properties as does the specimen of
Example 1.
EXAMPLE 17
The process of Example 1 is repeated excepting that
the lubricant is the reaction product of dipropyl 3, 3'
diallyloxy-2,2'-dihydroxy-amine and stearic acid, and the test
specimen has substantially the same properties as does the
specimen of Example 1.
EXAMPLE 18
The process of Example 1 is repeated excepting that
: the lubricant is the reaction product o~ diisopropanolamine and
stearlc acid, and the test specimen has substantially the same
properties as does the specimen of Example 1.
E~MæLE 19
The process of Example 1 is repeated excepting that
the lubricant is the ethylene oxide adduct of the lubricant used
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in Example 1. This adduct has an average o~ 4 ethylene oxide
groups per molecule in the hydroxy-containing side chains of
the amine that is reacted with the stearic acid. The test
specimens produced have substantially the same properties as do
those of Example 1.
From the above data it will be seen that there is a
cooperation between the lubricants used in the present invention
and the film formers which provides improved lubricity and
protection during the wet and dry stages of strand formation
and processing, while at the same time providing an increased
bonding action between the coated glass fibers and the matrix
polymer which the fibers reinforce. It will be seen that the
lubricant is a reaction product of a fatty acid and a secondary
amine, which secondary amine has two side-chains each of which
has at least one OH group therein~ The amine nitrogen plus the
OH groups provide a strong hydrophilic radical which is capable
of carrying the fatty acid into solution therewith. These
solubilizing side chains may include hydrocarbon fractions
pxovided that they also include oxygen atoms in a ratio of at
least one oxygen atom for every 4 carbon atoms~
The improved lubricant portion of the inventive size
formulations, therefore, comprises a molecule having a single
fatty acid tail that forms an ester with amine hydrogen. The
other side of the amine nitrogen are two side chains, each of
which has OH functionality. It is known that glass fibers when
wetted with water hold a layer of water on the surface of the
glass which-tends to be-high in OH groups. The lubricant of the
present invention differs from most prior art lubricants in that
the lubricant is linear in nature with the OH groups on one side
o~ the amine nitrogen and the fatty acid radical portion on the
.
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opposite side of the amine nitrogen. The nitrogen becomes
cationic in the size formulation and so is attracted to the
surface of the glass, with the OH containing chains projecting
into the water layer on the surface of the glass fibers, and
with the fatty acid radicals extending generally perpendicular
thereto in close pack formation. In most prior art size
formulations, the cationic lubricants, particularly where they
are not linear, may lay flatwise on the glass to provide
hinderance to the attachment of other molecules to the glass
surface. In the size formulation of the present invention, the
lubricants are believed to form a coating wherein the fatty acid
portions of the molecules extend parallel to each other away
from the surface of the glass to provide a substantial coating
thickness on the glass surface in which the lubricant portion
of the molecules are oriented outwardly in close pack formation.
The fibers, therefore, are completely separated by coatings of a
substantial nature having a lubricous surface. Even after the
fibers are dried, it appears that at least some of the cationic
lubricant remains to lubricate the surface of the glass.
When the coated fibers are embedded in a matrix resin,
including a thermoplastic matriY. resin, however, the lubricant
molecules leave th~ glass and diffuse between the polymer chains.
Because the lubricant used in the present invention has two -^
side chains, each of which has at least one OH group thereon,
these side chains are capable of hydrogen bonding to polar
elements of the matrix polymer. Since there are two OH groups,
one on each side chain, one side chain is capable of bonding to
one polymer molecule while th~ other side chain is capable of
hydrogen bonding to the adjacent polymer molecule. This
functionality lS believed to account for the increase in strength
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that it provides to the matrix polymer. Because the lubricant
molecules are essentially linear, the fatty acid radical
portion or lubricating portion is capable of laying down between
the polymer chains to act as an innocuous plasticizer, which
in some instances may decrease the brittleness of the matrix
polymer. As pointed out previously, the side chains containing
the OH groups may have appreciable length provided that they
contain at least one oxygen for every 4 carbon atoms. Since
this oxygen is also capable of hydrogen bonding, and is also
capable of contributing to water solubility, the additional
oxygen atoms offset the hydrophobic nature of the carbon atoms.
In this respect, repeating-ethylene oxide groups are a preferred
chain lengthener, and it is believed that a slight increase in
ductility is achieved as the length of the hydrophilic side
chains is increased.
The lu~ricants used in the present invention,
- therefore, can be characterized as esters, as are formed as for
example, by the reaction of a fatty acid and a secondary amine,
which secondary amine has two hydrophilic side chains each of
which contains at least one OH group. These side chains are
; hydrophilic if they include at least one oxygen for every four
- carbon atoms therein. In one embodiment o such materials the
hydrophilic side chains may be increased in length by reacting
the alcohol radicals with ethylene oxide, as is well known.
Because the lubricant molecules have an affinity for polymers,
it is believed that the lubricant molecules migrate away from the
surface of the glass and diffuse throughout the laminating
~olymer during molding and thereby allow the laminating polymer
access to the surface of the glass couplings agents thereon.
It will, therefore, be seen that the lubricant used in the
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presen~ invention do a flip flop from the position and function
which they provide in the wet condition of the fibers to that
which they occupy and provide when fused to the matrix polymers.
It is highly unusual for a lubricant to actually increase the
strength of the bond between a matrix polymer and glass fibers,
and the lubricants used in the present invention are capable of
accomplishing this result with any matrix resin, be it thermo-
plastic or thermosetting. What is more, increased s~rength is
provided whether or not a glass coupling agent is used, but in
the preferred embodiments where the highest strength is desired,
glass coupling agents of the silane type, and particularly the
cationic silanes containing one organo group with nitrogen
therein, will be used. The amount of the silanes used is not
critical, since the effectiveness increases generally
proportionately with the amount used until amounts up to
approximately 5% of khe coating size are included.
Preferred size formulations will generally comprise
the following materials in parts by weight:
- Materials Parts by Weight
20 Film forming polymer 2 - 12 r
Silane glass coupling agent 0.1 - 5.~
Cationic lubricant as defined above0.1 - 5.0
Water 78 - 97.8
Preferred film formers to be used in the sizes of the
present invention are epoxy polymers, particularly of the
bisphenol A type, and the polyurethanes. Residual oxirane groups
of the epoxies are capable of achieving good bond with the OH
groups of the lubricant and are catalyzed by the amine nitrogen.
What is more, they have good glass wetting properties. In this
3~ respect, the benzene rings of the bis-phenol A are beneficial.
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The urethanes, if any isocyanate groups remain, are also capable
of reacting with OH groups of the lubricant and are also
cationic and have good glass wet out properties. As pointed out
above, polyesters can be used since they çontain polar oxygen
either as ester groups or as acids or hydro~yl groups.
Where the size formulations are to coat glass that is
to reinforce nylon, the following formulations are found to be
most beneficial:
- Materials Parts by Weight
Epoxy emulsion solids 5.0 - 12.0
Polyurethane latex solids 0 - 7.0
Silane glass coupling agent 0.1 - 5.0
Lubricant described above 0.1 - 5.0
Water Balance
A specific noteworthy formulation is:
Materials - Parts by Weight
Emulsified particles of a 7.00
Bisphenol A type epoxy film former
Polyurethane film former 0.50
20 Gamma-aminopropyltrialkoxysilane 1.40
Cationic lubricant 0.50
Having described the invention in considerable detail,
~ I do not wish to be limited to the particular embodiments shown
; and described, and it is my intention to cover hereby all novel
adaptations, modifications, and arrangements thereof which
come within the practice of those skilled in the art to which
; the invention relates.
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