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WO1990006329A1 - Isolateur thermique constitue de triazine phenolique et procede s'y rapportant - Google Patents

Isolateur thermique constitue de triazine phenolique et procede s'y rapportant Download PDF

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Publication number
WO1990006329A1
WO1990006329A1 PCT/US1989/005090 US8905090W WO9006329A1 WO 1990006329 A1 WO1990006329 A1 WO 1990006329A1 US 8905090 W US8905090 W US 8905090W WO 9006329 A1 WO9006329 A1 WO 9006329A1
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WO
WIPO (PCT)
Prior art keywords
insulator
resin
phenolic
piston
phenolic triazine
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US1989/005090
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English (en)
Inventor
Ming-Jye Lan
Bruce Todd Debona
Lawrence Edward Mcallister
Sajal Das
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Honeywell International Inc
Original Assignee
AlliedSignal Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by AlliedSignal Inc filed Critical AlliedSignal Inc
Publication of WO1990006329A1 publication Critical patent/WO1990006329A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G8/00—Condensation polymers of aldehydes or ketones with phenols only
    • C08G8/04—Condensation polymers of aldehydes or ketones with phenols only of aldehydes
    • C08G8/08—Condensation polymers of aldehydes or ketones with phenols only of aldehydes of formaldehyde, e.g. of formaldehyde formed in situ
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G73/00—Macromolecular compounds obtained by reactions forming a linkage containing nitrogen with or without oxygen or carbon in the main chain of the macromolecule, not provided for in groups C08G12/00 - C08G71/00
    • C08G73/06—Polycondensates having nitrogen-containing heterocyclic rings in the main chain of the macromolecule
    • C08G73/0622—Polycondensates containing six-membered rings, not condensed with other rings, with nitrogen atoms as the only ring hetero atoms
    • C08G73/0638—Polycondensates containing six-membered rings, not condensed with other rings, with nitrogen atoms as the only ring hetero atoms with at least three nitrogen atoms in the ring
    • C08G73/065—Preparatory processes
    • C08G73/0655—Preparatory processes from polycyanurates

Definitions

  • the present invention is in the field of thermal insulators. More particularly, the present invention relates to a thermal insulator made of a phenolic triazine resins.
  • the phenolic triazines which have been disclosed have been found to have high thermal stability.
  • Copending U.S. ser. No. 041,018 filed as PCT/US 87/00123, and U.S. Ser. No. 104,700 filed October 5, 1987, hereby incorporated by reference disclose phenolic cyanate and phenolic triazine resins.
  • the phenolic cyanate resins are disclosed to be stable as measured by gel time.
  • the phenolic triazine resins are disclosed to be thermally stable as measured by Thermal Gravimetric Analysis.
  • Novolac resins are highly flame resistant, but are not high temperature resins.
  • the temperature stability of novolac resins is limited because of oxidative
  • Two areas that must be insulated from the thermal environment of the brake are the fluid in the brake hydraulic system and the main axle.
  • the hydraulic fluid must be protected by an insulator on the hot side of the hydraulic piston.
  • the axle must be protected by an insulator between the axle and the brake torque tube.
  • Fiberglass laminated composites prepared with thermosetting silicone resins exhibit acceptable thermal stability, but mechanical properties are inadequate. Polyimides may provide acceptable properties as demonstrated on small experimental panels. However, processing of fiberglass reinforced components of the size and shape needed for these applications is beyond current capability.
  • Pistons and insulator assemblies having structure as shown in Figure 1 are known except for the makeup of insulator.
  • the insulators are made of short asbestos fibers randomly reinforcing a phenolic resin. It is also known to use fiberglass layers reinforcing silicon resin. Silicon resin has been found to deteriorate from exposure to high temperatures .
  • the present invention is an insulator comprising a reinforced phenolic triazine resin.
  • the reinforcement is preferably a fibrous material.
  • the reinforcement can be in the form of chopped fiber reinforcing filler or fibrous layers made from woven fabric layers of unidirectional fibers, or nonwoven fibrous mat.
  • the insulator is made of a plurality of fibrous layers.
  • the fiber is a temperature resistant fiber such as fiberglass, asbestos, carbon, graphite, boron, cellulose, titanate, metallic and mixtures thereof.
  • the fibrous layers are embedded in a phenolic triazine resin matrix.
  • a specific and preferred embodiment of the present invention is the use of the insulator in the shape of a cylinder preferably a hollow cylinder.
  • the cylinder is reinforced with fibrous materials.
  • the cylinder is made of a
  • the fibrous layers can be wrapped so that they form circumferential layers around the axis of the cylinder.
  • the fibrous layers can be lamianated in a direction perpendicular to the axis.
  • the cylinder can be solid.
  • the cylinder can have an outside
  • diameter of from 1 to 30 centimeters in length.
  • the insulator of the present invention should have structural integrity.
  • the insulator of the present invention particularly where used in applications such as piston insulator, should have structural integrity.
  • the present invention also includes a method of insulating a heat source at a temperature up to 400°C.
  • the insulator is made of a composition comprising a phenolic triazine resin. Both triazine as well as the cyanate ester formation deactivate the benzene nucleus of the phenolic resin and thus inhibits peroxide formation at the methylene linkage, through both steric and inductive effects. Thermal and oxidative stability is enhanced and the possibility of afterglow or punking is deminished. In addition to thermal and oxidative stability, the
  • phenolic triazine of the present invention is derived from a cyanato group containing phenolic resin of Formula I:
  • n is a positive whole number greater than or equal to 1, preferably 4 to 20, and more preferably 4 to 10;
  • q and r are the same or different at each occurrence and are whole numbers from 0 to 3, with the proviso that the sum of q and r at each occurrence is equal to 3, preferably of q is equal to 0 or r is equal to 3;
  • Z is -CN, or hydrogen and -CN;
  • o and p are the same or different at each occurrence and are whole numbers from 0 to 4 with the proviso that the sum of o and p at each occurrence is equal to 4, preferably o is equal to 0 and p is equal to 4;
  • -X- is a divalent organic radical
  • R 3 is the same or different at each occurrence and is a substituent other than hydrogen .which is unreactive under conditions necessary to completely cure the
  • X is preferably a radical selected from the group consisting of: -CH 2 -, -CO-, -SO 2 -, CH 2 -, (S)y
  • R is preferably selected from hydrogen and methyl groups.
  • the cyanato group containing phenolic resin can be incompletely (partially) crosslinked or fully crosslinked to form the phenolic triazine resin of the present
  • the phenolic triazine can be formed by heating the cyanato group containing phenolic .resin is stable and has a long shelf life. This is indicated by the gel time of greater than 1 minute, preferably greater than 2 minutes, more preferably greater than 10 minutes at 155o C, and most preferably greater than 20 minutes at 155o C.
  • the cyanato group containing phenolic resin cures to form a phenolic triazine which can be characterized as having a thermal stability indicated by thermal decomposition temperature of at least 400o C and preferably of at least 450oC as measured by Thermal Gravimetric Analysis (TGA). This is important to enable articles made of compositions comprising phenolic triazine resin to provide insulation against heat sources up to 400oC.
  • TGA Thermal Gravimetric Analysis
  • the cyanato group containing phenolic resin useful to make the phenolic triazine resin insulator of the present invention preferably has a number average molecular weight of from 300 to 2000, preferably 320 to about 1600, more preferably about 500 to 1500 and most preferably about 600 to 1500, and yet more preferably about 700 to 1300.
  • Figure 1 is a piston and insulator assembly
  • Figure 2 is a schematic cross-sectional view of a piston and insulator as part of a brake assembly.
  • Figure 3 is a partial cross-section view of the piston insulator of the present invention in a disc brake environment.
  • Figure 4 is a partial cross-section view of the insulator of the present invention is a disc brake in an embodiment of an axle insulator.
  • Figure 5 is partial isometric sectional view of the axle insulator in a disc brake assembly.
  • the present invention is an article of manufacture comprising an insulator; and a method of insulating.
  • the insulator of the present invention comprises a reinforced phenolic triazine resin.
  • the reinforcement can be a fibrous material.
  • the fibrous material can be dispersed as a reinforcing filler throughout the resin or alternately be in a web-type construction.
  • the web can be woven, two or more of unidirectional fiber layers, or nonwoven.
  • the insulator is made of a plurality of fibrous layers.
  • Useful fibers include but are not limited to fibers that can be selected from the group consisting of fiberglass, asbestos, carbon,
  • Useful fibers can be selected from the group consisting of:
  • fibrous layers consisting of high-strength fibers such as polyaramides, boron, titanate and the like.
  • the fibrous layers are embedded in a phenolic triazine resin matrix.
  • a preferred insulator of the present invention is a cylindrical shaped insulator.
  • the cylindrical can be hollow.
  • the cylinder can be used as a piston insulator or an axle insulator in braking systems.
  • the insulator is a cylinder, the cylinder can have an outside diameter of from 1 to 30, preferably from 2 to 25 and more preferably from 3 to 17
  • the cylinder is from 1 to 10, preferably from 2 to 8 and more preferably 3 to 8
  • the cylinder is hollow and has an outside diameter of from 15 to 18 centimeters, an inside diameter of from 13 to 16
  • the insulator of the present invention resists substantial loss in mechanical properties including strength and modulus when exposed to temperatures of up to 400oC for 30 minutes.
  • the present invention includes a method of insulating a heat source which is at a temperature of up to 400oC; can be as high as 450°C; and is typically in a range of from 159°C to 250°C, with an insulator comprising
  • the insulator of the present invention has
  • phenolic triazine resin useful in the present invention has Formula I where X is preferably a radical selected from the group consisting of: -CH 2 -, -CO-, -SO 2 -, Q CH 2 -, (S)y and -CH 2 CH 2 -,
  • R is preferably selected from hydrogen and methyl groups.
  • the phenolic cyanate resin has unproved gel time and long shelf life.
  • the gel time as measured by the Hot Plate Stroke Cure Method of greater than 1 minute, preferably 2 minutes, more preferably greater than 10 minutes, and most preferably greater than 20 minutes at 155o C.
  • the phenolic triazine resin has low volatiles, and excellent char yield and thermal properties. Useful resin having these properties is described in U.S. Serial No. 104,700 filed October 5, 1987 and hereby incorporated by reference. This reference sets forth the Plate Stroke Case Method.
  • the thermal stability of the phenolic triazine resin useful in the present invention is indicated by whether the reins is capable of forming a phenolic triazine resin having the thermal decomposition temperature of at least 400oC and preferably of at least 450°C as measured by Thermal Gravimetric Analysis (TGA).
  • TGA Thermal Gravimetric Analysis
  • the decomposition temperature is when the sample begins to have a measured weight loss.
  • the phenolic triazine resin of the present invention has a char value (weight loss) at 800°C of at least 50% by weight, preferably from 50 to 70% by weight, and more preferably 60 to 70% by weight.
  • the improved properties of the resin of the phenolic cyanate resin used in the present invention are attributed to the purity of the resin, preferably the resin has a residual amount of a dialkyl cyanamide, typically diethyl cyanamide of less than 2% by weight, preferably less than 1% by weight and most preferably substantially none.
  • the diethyl cyanamide is undesirable because it generates smoke upon curing.
  • the cyanato group containing phenolic resin has a residual amount of phenyl cyanate of less than 2% by weight and preferably less than 1% by weight and most preferably less than 0.5% by weight. This is
  • phenyl cyanate is a volatile material that contributes to thermal
  • phenyl cyanate acts as a chain inhibitor for cyclotrimerization reaction.
  • the phenolic cyanate resin useful in the present invention is satisfactory and results in satisfactory cured triazine materials regardless of molecular weight.
  • the preferred molecular weight range of the phenolic cyanate resin is a number average molecular weight of 300 to 2000, preferably 320 to about 1600, more preferably about 500 to 1500 and most preferably from about 600 to 1500 and yet more preferably 750 to 1300.
  • the molecular weight distribution and number average molecular weight of the cyanato group containing phenolic resin can be
  • the phenolic cyanate resin forms a phenolic triazine network upon heating and/or in the presence of a curing agent.
  • Typical curing conditions are from 150 to 250oC at 100 to 500 psi pressure for .1 to 1 hour depending on sample size, or by autoclave at low pressures including pressures below 100 psi.
  • the high density of cross linkage of the cured products results in excellent
  • characteristics including thermal properties and a glass transition temperature of 300°C or higher.
  • the phenolic triazine resin useful in the insulator of the present invention is formed by the curing of the cyanato group containing phenolic resin.
  • the puring reaction is known as "cyclotrimerization".
  • the glass transition temperature of the cured resin is greater than 300°C, measured by DMA, dynamic mechanical analysis.
  • a preferred phenolic triazine resin begins with a phenolic novolac backbone. This is reacted with cyanogen halide such as cyanogen bromide (CNBr) is presence of an organic base, such as triethylamine (Et 3 N) in a solvent such as tetrahydrofuran (THF) to form phenolic cyanate
  • cyanogen halide such as cyanogen bromide (CNBr)
  • organic base such as triethylamine (Et 3 N)
  • solvent such as tetrahydrofuran (THF)
  • n and n are integers, typically there are 80 to 100 percent of n units and 20 to 0 percent m units. Under the influence of heat and/or a suitable catalyst
  • phenolic-cyanate forms phenolic cyanate-phenolic triazine precursor.
  • the phenolic cyanate-phenolic triazine precursor resin can be used to form phenolic-triazine resin.
  • the phenolic cyanate resin of the present invention cnn be derived from a phenolic novolac.
  • Useful phenolic novolac resins are known in the art. A typical and useful one is disclosed in U. S . Patent No . 4 , 022 , 755 at column 2 beginning at line 27.
  • Particularly useful phenols include phenol, cresol and xylenol.
  • a preferred method of making the phenolic triazine useful in the insulator of the present invention is to make the cyanato group containing phenolic resin recited above. This comprises the steps of reacting novolac resin and a trialkyl amine in a suitable organic solvent, preferably a cylic ether solvent to form the
  • the method is conducted at a temperature range of below -%oC, preferably from -5o C to -65°C, more preferably from -30°C to -65°C and most preferably from -45°C to -60°C.
  • reaction product is in solution in the cyclic ether.
  • This reaction product is a cyanato group
  • a nonsolvent vehicle Useful nonsolvents ae alcohols with isopropanol being preferred.
  • the separation is preferably conducted at atmospheric pressure. While it can be conducted at room temperature, the temperature is typically from -0°C to -45°C, preferably -5 C to -25°C. Precipitation is preferably conducted with agitation.
  • the improved properties of the resin used in the present invention are due to reacting the phenolic cyanate resin and a triakyl amine in a cyclic ether solvent to form the trialkylammonium salt of novolac resin this is followed by reacting the trialkylammonium salt with a cyanogen halide in the cyclic ether to form the phenolic cyanate resin.
  • the reaction is conducted at below about -5°C, preferably to -5oC to -65oC, more preferably from -30°C to -65°C and most preferably from -45oC to -60°C.
  • the cyclic ether solvent has been found to be an important reaction medium to form the phenolic cyanate resin of the present invention.
  • the cyclic ether solvent is preferably selected from the group consisting of:
  • the trialkyl amine can be selected from triethyl amine, tripropylamine and triethylcyclohexyl amine. Additionally, the raction medium can contain other bases to control the pH to help control the rate of the reaction.
  • Concentrations can be measured as a function of the weight percent of the trialkyammonium salt which could theoretically be calculated based on the weight of the trialkylamine, phenolic resin and solvent.
  • the amount of trialkylammonium salt is from 5 to 35, more preferably 10 to 25, and most preferably from 10 to 20 percent by weight. The preferred concentration can vary depending on the specific solvents and reactants used.
  • the formation of the phenolic cyanate resin used to make the insulator of the present invention is followed by reinforcing this resin.
  • the reinforcing fiber can be mixed into the phenolic cyanate resins by methods known to mix such fibers into phenolic resin.
  • Fibros webs can be coated with phenolic cyanate resins by methods known to coat fibrous with phenolic resin.
  • the reinforced resin can be cured by the application of heat or by the use of a suitable catalyst or a
  • the phenolic cyanate resin can be cured into a phenolic triazine resin in a suitable form and the cured structure shaped by appropriate means such as cutting into the suitable configuration for an
  • the resin can be incompletely cured followed by forming into an insulator.
  • the article formed of the incompletely cured resin can be used as a blank.
  • the blank can be further formed and then cured to form the phenolic triazine insulator.
  • the insulator can be made of compositions comprising short fiber up to 1/2 inch long and preferably from 1/16 to 1/4 of an inch long, and/or long fibers greater than 1/2 inch long. More preferred ar insulators made using long or continuous fibers, coated with resin -in impregnated into resin layers.
  • the composition comprises from 5 to 150 and preferably 25 to 75 weight percent of the short fibers.
  • the composition comprises from 5 to 150 and preferably 25 to 75 percent by weight of the long fibers.
  • the fiber to resin volume ratio depends on the application to be used. Properties to be considered include impact resistance, heat resistant, wear
  • the resin impregnated articles of the present invention contain coated fibers having 25 to 80, preferably 50 to 80, and more preferably 60 to 75 volume percent fiber.
  • the fibers may be pre-coated with the phenolic cyante resin or partially cured phenoliccyanate resin of the present invention.
  • the coated fibers can be pultruded, filament wound, or formed into layers.
  • the coating may be applied to the fiber in a variety of ways.
  • One method is to apply the resin of the coating material to the fibers either as a liquid, a sticky solid or particles in suspension, or in a fluidized bed.
  • the coating may be applied as a solution in a suitable solvent which does not adversely affect the properties of the fiber at the temperature of the
  • liquid capable of dissolving or dispersing the resin of the present invention can be used, preferred groups of solvents include acetone, methyl ethyl ketone, methylene chloride and methyl isobutyl ketone (MIBK).
  • MIBK methyl isobutyl ketone
  • the fibrous web can be coated or embedded in phenolic cyanate resin to form single layers which are called prepreg layers.
  • the prepreg layers can be made of the fiber impregnated or coated with phenolic cynate resin.
  • the prepreg layers can be cured to make a phenolic
  • the fiber used in the prepreg layer can be any fibrous network woven or non-woven.
  • Useful fibers include fiberglass, asbestos, carbon, graphite, boron, cellulose, titanates, polymers such as polyesters, polyamides, polyaramides, polyacrylics, ultra high molecular weight polyolefins including polyethylene and polyvinyl alcohol, metallics, amorphous metals such as those sold under the tradename Metglas by Allied-Signal, Inc. and mixtures thereof.
  • the composite articles of the present invention can be made of fibers arranged in networks having various configurations.
  • a plurality of fibers can be grouped together to form a twisted or untwisted yarn.
  • the fibers or yarn can be formed into felt, knitted or woven (plain, basket, satin and crow feet weaves, etc.) into a network fabricated into non-woven fabric articles in parallel array, layered or formed into a fabric by any of a variety of conventional techniques.
  • a useful technique for preparing preferred prepregs of the present invention comprised of substantially parallel, unidirectionally aligned fibers includes the steps of pulling fiber through a bath containing a
  • a suitable form such as a cylinder.
  • the solvent is then evaporated leaving a prepreg sheet of fiber embedded in a phenolic cyanate matrix that can be removed from the cylinder after proper curing.
  • a plurality of fibers can be simultaneously pulled through the bath of the resin solution and laid down in closely positioned, in substantially parallel relation to one another on a suitable surface. Evaporation of the solvent leaves a prepreg sheet comprised of the resin coated fibers which are substantially parallel and sligned along a common fiber direction. The sheet is subsequently processed such as by laminating one sheet to another.
  • Yarn useful in composites can be produced by pulling a group of filaments through the solution of the phenolic cyanate resin to substantially coat each of the individual filaments, and then evaporating the solvent to form coated yarn.
  • the yarn can then for example be employed to form fabrics, which in turn can be used to form composite structurers.
  • the yarn can also be processed into
  • composites by employing conventional filament winding techniques.
  • the composite can have coated yarn formed wound into overlapping fiber layers.
  • Fabrics can also be coated with the phenolic cyanate resin of the present invention.
  • Such fabrics can include woven fabrics as described above as well as non-woven mats.
  • the insulator of the present invention can be any suitable material.
  • the insulator of the present invention can be any suitable material.
  • Figure 1 illustrates a piston and insulator assembly 10 which has the insulator of the present invention.
  • the insulator comprises a reinforced phenolic tirazine resin.
  • the assembly comprises a piston 14 and the piston
  • the outside diameter of the piston and piston insulator are preferably equal.
  • insulator 18 is cylindrical in shape having an insulator piston end 2o and an insulator front end 22. Planes through the insulator piston end 20 and insulator from end 22 are preferably perpendicular to the axis 21 of the cylindrical insulator 18.
  • the insulator 18 can be
  • FIG. 1 is to have a tubular clip 24 connected into an axial opening in the top surface 16 or the piston.
  • the insulator is connected to the piston by an insulator hold down pin 26 which passes through an insulator pin shaft in 28.
  • the shaft 28 passes from insulator front end through the insulator to the insulator piston end and is connected to the tubular clip.
  • the shaft 28 is axial and shaped into a form similar t the outer diameter of the insulator hold-down pin.
  • the insulator hold-down pin 26 has a connecting end 32 which fits into tubular clip 24 to maintain piston
  • the piston insulator illustrated in Figure 1 is about 2.54 cm long, 3.175 cm outside diameter and 1.5 cm inside diameter. It is made of layers of fiberglass impregnated with resin. The layers are perpendicular to the axis of the piston insulator cylinder.
  • Pistons and insulator assemblies having the structure as shown in Figure 1 are known except for the makeup of insulator.
  • the insulators are made of short asbestos fibers randomly reinforcing a phenolic resin. It is also known to use fiberglass layers reinforcing silicone resin. Silicone resin has been found to deteriorate from exposure to high temperatures.
  • the phenolic triazine resin of the present invention has been found to have improved thermal and physical properties compared to silicone resin.
  • an insulator protector plate 34 on the insulator front end.
  • the insulator protector plate 34 can be connected to the front end 22 of the insulator 18 by hold-down pin 26.
  • the insulator protector is preferably made of a hard metal composition which would protect the front end 22 of the insulator 18 as it pushes against corresponding elements in the brake or other in which the piston with the piston insulator is located.
  • the piston insulator thermally insulatest he piston from a heat source which may directly or indirectly come into contact with the front end 22 of the insulator 18. Were the insulator not there, the heat source would then come directly in contact with metallic elements of the piston.
  • Figure 2 illustrates the piston assembly 10 in a piston housing where the piston and insulator assembly is shown in its environment.
  • the piston 14 is set in a piston housing 38.
  • the piston housing has a piston housing boar 40 which the piston is located.
  • the piston base 42 is in contact with hydraulic fluid passages 44 through which fluid can assert pressure on the piston base 42 forcing it in the direction of the front end 22 of the insulator.
  • the insulator is shown with a insulator protection plate 34.
  • the insulator protection plate is forced against a pressure plate 46.
  • the pressure plate activates the brake mechanism. This is accomplished by causing rotor discs to contact stator discs.
  • the thermal energy generated by the friction between the rotating and stationary discs causes them to heat to temperatures as high as 1500°C with surface temperatures reaching up to 3000°C in aircraft brakes.
  • the insulator resists the heat flow from the hot brakes to the hydraulic fluid.
  • Figure 3 further shows the illustration of the piston assembly shown in Figure 2 in the environment of a braking mechanism.
  • the assembly is generally shown in a sectional view of a disc brake.
  • the piston and insulator assembly 10 forces the rotar 48 and stator 50 elements of the disc brake together causing the brake to engage.
  • the insulator of the present invention can be molded into a hollow cylindrical shape to make an axle insulator also used as part of disc brake assemblies.
  • One such axle insulator in a disc brake is shown as reference character 52 in Figure 4.
  • the axle insulator insulates axle 54 from the heat generating braking environment of the rotor and stator elements which cause housing 56 to heat up.
  • the axial insulator 52 is located between- torque tube 56 and axle support 58. In this way the axial is separated from the heat source which in this case is the friction
  • Figure 5 illustrates a brake assembly showing the axle insulator in position.
  • the present invention includes a new use of a known material.
  • the known material is the phenolic tirazine resin.
  • Phenolic triazine resin reinforced with fiberglass are known from companion patent application Serial No. 232,407 filed August 15, 1988. There is no disclosure or suggestion that a reinforced phenolic triazine resin could be used as a thermal insulator particularly when it is reinforced.
  • the present invention has found such a use in an aircraft brake system as insulators for the piston and for the axle. This insulator of the present invention has low thermal conductivity
  • the compressive strength is preferably at least 50,000 psi when measured in accordance with ASTM D695, and the interlaminar shear strength is preferably greater than 5,000 psi when measured according to ASTM D2344.
  • the mechanical properties must be retained over a temperature range of from -65 to 750oF.
  • the insulator of the present invention considering both fabric and phenolic triazine resin must be resistant to fluids commonly encountered in their environments including lubricants, hydraulic fluids and solvents.
  • the phenolic triazine resin of the present invention can be made by methods such as disclosed in our co-pending applications. PCT US88/00119 and U.S. Serial No. 104,700, both hereby incorporated by reference.
  • This example illustrates the preparation of an insulator of the present invention.
  • Phenolic cyanate resin was synthesized from phenolic novolac resin.
  • the phenolic novolac resin had a number average molecular weight of about 620 as measured according to vapor phase osmometry. 1378 grams was dried in a vacuum oven at 40°C for 48 hours. This was added to a 12 liter 3 neck round bottom flask which was equipped with an air driven stirrer. There was a nitrogen inlet and an addition funnel. Seven liters of tetrahydrofuran was charged to the flask under nitrogen. The dried novolac resin was dissolved in the tetrahydrofuran at room temperature under the nitrogen. 1433 grams of
  • TAA triethylamine
  • Cyanogen bromide (CNBr) solution was prepreg.
  • a 22 liter 4 neck round bottom blask was charged with 7 liters of tetrahydrofuran (THF) and fitted with a nitrogen inlet.
  • a thermometer, an addition funnel and an air driven stirrer were also fitted to the flask.
  • the whole step-up was placed in a dry-ice/acetone cooling bath which was at a temperature of -65°C. 1623 grams of cyanogen bromide was dissolved in the tetrahydorfuran at room temperature and nitrogen purge was begun.
  • the temperature of the cyanogen bromide solution was brought to -60°C.
  • the novolac triethylamine salt solution prepared was placed in the addition funnel and slowly added to the cyanogen bromide solution. The addition time was 3 hours.
  • the reaction temperature was maintained at approximately -40oC. As the reaction proceeded, the by-product triethylammonium bromide salt was seen as a white solid.
  • the reaction product formed was the cyanated phenolic novolac resin.
  • reaction mixture was filtered through a course fritted glass funnel coated with about 1/8 inch of silica gel produced by Merck, Grade 60, 60 angstroms. The filtrate was a clear yellow
  • the reaction product (novolac cyanate resin) was precipitated in a 15 gallon bucket. 28 liters of
  • isopropanol (IPA) was charged to the bucket and coled to -20°C on a dry ice/acetone cooling bath. The filtrate was placed in an addition funnel and added to the isopropanol over a period of 2 hours under vigorous stirring. After precipitation, the product mixture was filtered through a 60 micron filter cloth made of nylon and transferred to a 5 gallon bucket. Two gallons of isopropanol was added to the white product and this mixture was stirred for one half hour at room temperature and the product was filtered again. The isopropanol washing was repeated twice. The product was filtered and dried on a Buchnel funnel overnight and then transferred to a room temperature vacuum open todry until the solid content reached greater than 98% by weight. This material was then the phenolic cyanate resin. The phenolic cyanate resin was impregnated onto a
  • the fiberglass was coated using 250 ml of a 50 weight percent solution of the phenolic cyanate resin in methyl ethyl ketone (MEK). This solution was poured into a throgh. A piece of 7 inch by 7 inch by 0.029 inch fiberglass fabric was pulled through the resin solution through two rolls. The clearance between the two rolls was set to 0.356 mm. The fabric was pulled through the rolls after a 3 minute immersion in the phenolic triazine resin solution. This impregnated fiber was considered to be a prepreg. The prepreg was then placed on a piece of Teflon sheet under a hood in order to evaporate the MEK solvent. After 48 hours under the hood, the resin content of the prepreg was determined to be 35 to 40 weight percent.
  • MEK methyl ethyl ketone
  • the fiberglass impregnated with phenolic cyanate resin was compression molded to form laminates. 29 plies of 6 inch by 6 inch prepregs were loaded into a mold. A ply is one prepreg layer. The mold was put into a platen press where the platens were preheated to 115oC. The mold was compressed under contact pressure and held for 20 minutes after the temperature of the mold reached 115oC. The mold was pressurized to 1000 psi and heated to 200°C and held for one hour. The mold was cooled to room temperature at a pressure of 1000 psi. The resin content of the laminate was determined to be about 30 to 35% by weight. The laminate was 0.25 inches thick.
  • a second laminate was made using 57 piles of circular prepreg sheets having a diameter of 2.875 inches.
  • the laminate was made as described above with the pressure at 1000 psi and heated to 200oC where it was held for one hour.
  • the mold was cooled to room temperature at a pressure 1000 psi pressure.
  • the resin content of the laminate was determined to be 35 to 48 percent by weight.
  • the laminate was 0.5 inches thick.
  • the tow laminates prepared above was subjected to the following post cure cycle in an oven in air at ambient pressure.
  • the laminates were machined into test specimens for mechanical property testing.
  • Synthan-Taylor as GSC laminates NEMA (National Electrical Manufacturer's Association) Grade G-7 were used. This laminate is fiberglass reinforced with a thermosetting silicone resin matrix. Test specimens in Tables 2 and 3 of equal size were made, changes in properties with temperature increase has been compared.
  • Test results are summarized in Table 2 for composite laminates made using 29 plies as recited above.
  • Test results are summarized in Table 3 for composite laminate made using 57 plies as recited above. In Table 3, results are shown for two separate laminated panels made using 57 plies.

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  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Reinforced Plastic Materials (AREA)
  • Compositions Of Macromolecular Compounds (AREA)

Abstract

La présente invention concerne un isolateur thermique et un procédé s'y rapportant, l'isolateur thermique étant constitué de résine de triazine phénolique.
PCT/US1989/005090 1988-11-28 1989-11-17 Isolateur thermique constitue de triazine phenolique et procede s'y rapportant Ceased WO1990006329A1 (fr)

Applications Claiming Priority (2)

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US27651988A 1988-11-28 1988-11-28
US276,519 1988-11-28

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WO1990006329A1 true WO1990006329A1 (fr) 1990-06-14

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140083805A1 (en) * 2012-09-27 2014-03-27 Shimano Inc. Disc brake caliper, brake pads and pad pin
US12305726B2 (en) 2022-06-06 2025-05-20 Goodrich Corporation Multi-layer aircraft brake insulator

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1987004443A1 (fr) * 1986-01-23 1987-07-30 Allied Corporation Copolymeres de cyanate phenolique/triazine phenolique
WO1988005443A2 (fr) * 1987-01-16 1988-07-28 Allied Corporation Resines phenoliques contenant un groupe cyanato et triazines phenoliques derivees de ces resines
EP0324908A2 (fr) * 1987-12-28 1989-07-26 AlliedSignal Inc. Composition à résistance au frottement

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1987004443A1 (fr) * 1986-01-23 1987-07-30 Allied Corporation Copolymeres de cyanate phenolique/triazine phenolique
WO1988005443A2 (fr) * 1987-01-16 1988-07-28 Allied Corporation Resines phenoliques contenant un groupe cyanato et triazines phenoliques derivees de ces resines
EP0324908A2 (fr) * 1987-12-28 1989-07-26 AlliedSignal Inc. Composition à résistance au frottement

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140083805A1 (en) * 2012-09-27 2014-03-27 Shimano Inc. Disc brake caliper, brake pads and pad pin
US12305726B2 (en) 2022-06-06 2025-05-20 Goodrich Corporation Multi-layer aircraft brake insulator

Also Published As

Publication number Publication date
CA2003582A1 (fr) 1990-05-28

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