Title of Invention

A CYANATE ESTERS HAVING FLAME RESISTANT PROPERTIES

Abstract

This invention relates to a cyanate ester having flame resistant properties represented by formula(I): Wherein Z is C1-C4 alkylene group or a five or six membered cycolalkylene; R1, R5, R6 and R10, independently of one another, are unsubstituted or halogen- or C1-C3alkyl-substituted C1-C4 alkyl that can be saturated or unsaturated, halogen, H,-OCN, -OH, C1-C4ALKOXY, ALKYTHIO, mercaptan, nitro, -OCOR(C1-C3alkyl), -COR, -NO2, -NR'R", wherein R, R' and R" are H or C1-C3alkyl; R2, R4, R7 and R9, independently of one another, are C1-C4alkyl, halogen, H, -OCN, or -OH, C1-C4alkoxy, alkythio, mercaptan, nitro, -OCOR(C1-C3alkyl), -NCOR(C1-/C3alkyl), -COR, -NO2, -NR'R", wherein R, R' and R" are H or C1-C3alkyl; or R1 and R2 together and/or R2 and R3 together, and/or R9 and R10 together, and/or R8 and R9 together, independently of one another, form one or more aromatic rings or five or six membered cycloalkylene that can each be substituted with C1-C4alkyl or halogen; R11 and R12, independently of one another are H, phenyl, C1-C4alkyl or halogen; wherein at least one of aromatic rings A and B or at least one of the aromatic rings or the five or six membered ring formed by R1 and R2 and/or R2 and R3 and/or R9 and R10 and/or R8 and R9 is substituted by at least one cyanato group.

Full Text

This invention relates to novei aromatic cyanate ester compounds having at least two rings (inked by an unsaturated group containing member, prepolymers and compositions thereof, and processes for making the same. The compounds can be employed in adhesives, composites, laminates and molding compositions. The compounds and compositions thereof have particular utility for use in molded articles requiring flame-resistance, low peak heat release rates, such as interiors for aircraft and other transportation vehicles, and low total heat release rates without generating significant amounts of smoke. There is a need in the transportation industry, particularly for aircraft interiors, for molded polymeric components that exhibit very low peak heat release rates. Many cyanate esters exhibit good dielectric properties, water absorption and flame retardancy. However, all of the currently known cyanate esters fail to have heat release rates below 35 Joule/g-°K, more preferably below 10 Joule/g-°K. Low peak heat release rates can be attained using other high performance polymers such as polyphenylsulfone, polyamineimides, polybenzoimadazoles and polybenzoxazoles. AN of trie currently available polymers having relatively low peak heat release rates suffer from one or more disadvantages such as high cost of manufacture or challenging processing requirements. The present invention produces molded articles having the desired low peak heat release rate using cyanate ester compounds and compositions thereof. R11 and R12, independently of one another are H, phenyl, C1-C4alkyl or halogen; wherein at least one of aromatic rings A and B or at least one of the aromatic rings or the five or six membered ring formed by R1 and R2 and/or R2 and R3 and/or R9 and RlO and/or R8 and R9 is substituted by at least one cyanato group, A preferred compound is characterized according to formula (I) above wherein 2 is C1 -C2alkyiene; R1 and R10 are H; R2, R4, R7 and R9, independently of one another, are halogen, H, -OCN, or -OH; R3, R5, R6 and R8, independently of one another, are H, -OCN or -OH; R11 and R12 are halogen; and at least one of aromatic rings A and B is substituted by at least one cyanato group. A particularly preferred compound is characterized according to formula (I) above wherein Z is C1-C2alkylene; R1, R5, R6 and R10 are H; R2, R4, R7 and R9, independently of one another, are halogen or H; R11 and R12 are halogen; and R3 and R8 are -OCN. More preferably, R11 and R12 are chlorine or bromine. Most preferably, R11 and R12 are chlorine. A further preferred compound is characterized according to formula (1) above wherein Z is methylene; R1, R2, R4, R5, R6, R7, R9 and R10 are H; R3 and R8 are -OCN; and R11 and R12 are chlorine. The present invention relates, in a second aspect, to a prepolymepmixtur^ containing a ^cyclotrimerized reaction product of cyanate esters wherein at least one of said cyanate esters is the compound according to formula (I) above. Preferably, up to about 60% of the cyanato groups in the overall mixture are trimerized as a part of the cyclotrimerized reaction product. More particularly, about 10 to 40%, preferably, about 20 to 30% of the cyanato groups in the overall composition are trimerized as a part of the cyclotrimerized reaction product. The present invention relates, in a further aspect, to a composition containing a) a compound according to formula (I) above or a cyclotrimerized reaction product thereof and b) a solvent or c) a monocyanate ester different from component a). Preferably, component c) is at least one halogen-substituted or unsubstituted aromatic monocyanate ester selected from naphtho! cyanate, phenylphenol, chloronaphthol cyanate, chlorophenylphenol, dichloronaphthol cyanate, dichlorophenylphenol, bromonaphthol cyanate, bromophenylphenol, dibromonaphthol cyanate, dibromophenylphenol and mixtures thereof. The present invention, in a further aspect, relates to a composition containing a) a compound according to formula (I) above or a cyclotrimerized reaction product thereof and b) a thermally curable monomer or oligomer other than a cyanate ester. Preferably, the thermally curable or reactive monomer or oligomer is selected from an epoxy, bismaleimide, polyimide, polyester, epoxy-acrylate, urethane-acrylate, diallyl phthalate, spiropyrane, phenolic resin and mixtures thereof. The present invention, in a further aspect, relates to a composition containing a) at least 15%, preferably about 50 to 100%, more preferably about 60 to 99%, by weight of the overall composition of a compound according to formula (I) or a cyclotrimerized reaction product thereof with the balance of the composition optionally being at least one of components b) to g): b) solvent;.c) additional mono- and polycyanato-group containing compounds; d) thermal curable or reactive compounds other than cyanate esters; e) cure catalysts and/or accelerators; f) tougheners; and g) customary additives and fillers. A preferred process employs a halogen-containing aldehyde, acetal or hemiacetal selected from fluoropropanal, fluoroacetaldehyde, bromopropanal, bromoacetaldehyde, chloroethanal, chloropropanal, chloroacetaldehyde, 2-chioro-1-ethoxy ethanol, 2-fluoro-1-ethoxy ethanol, 2-bromo-l-ethoxy ethanol, difluoropropanal, difluroacetaldehyde, dibromopropanal, dibromoacetaldehyde, dichloroethanal, dichioropropanal, dichloroacetaldehyde,2,2-dichloro-1-ethoxyethanol, 2,2-difluoro-1-ethoxy ethanol, 2,2-dibromo-1-ethoxy ethanol, trifluoropropanal, trifluoroacetaldehyde, tribromopropanal, tribromoacetafdehyde, trichloroethanal, trichloropropanal, trichloroacetaldehyde, 2,2,2-trichloro-1 -ethoxy ethanol, 2,2,2-trifluoro-1 -ethoxy ethanol, 2,2,2-tribromo-1 -ethoxy ethanol and mixtures thereof. More preferably, the halogen-containing afdehyde, acetal or hemiacetal is selected from trichloroethanal, 2,2,2-trichloro-1-ethoxy ethanol and mixtures thereof. A preferred process employs an aromatic compound that is to be reacted with the halogen-containing aldehyde, acetal or hemiacetal in step (a) that is selected from phenol, chlorophenol, dichlorophenol, cresol, xylenil, carvacol, thymol, naphthol, anthrol, phenanthroi, pyrocatechol, resorcinol, chlororesorcinol, dichlororesorcinol, hydroquinone, chlorohydroquinone, dichlorohydroquinone, trichlorohydroquinone, dinaphthol, chlorodinapthol, dichlorodinaphtho! and mixtures thereof. The process described above can advantageously be practiced such that the reaction mixture in step (a) further comprises a minor amount of a non-aromatic alcohol. The preferred cyanogenhalide for practicing the process described above is selected from cyanogen chloride, cyanogen bromide and mixtures thereof. The present invention, in a still further aspect, relates to a cured article resulting from a curable mixture comprising a compound according to formula (I) above or cyclotrimerized reaction product thereof having a peak heat release rate of less than about 10 Joule/g-°K as measured using a pyroiysis-combustion flow calorimeter developed by the Federal Aviation Administration or a peak heat release rate of less than 30, preferably 25 as measured according to the Ohio State University heat release test. The present further relates to a cured article resulting from a curable mixture comprising a compound according to formula (I) above or a cyclotrimerized reaction product thereof having a total heat release of less than about 3 KJoule/g. The cured articles do not generate significant amounts of smoke during combustion. The present invention is a flame resistant aromatic cyanate ester compound, prepolymers thereof, and compositions containing the same, articles of manufacture, and methods of In a more preferred compound, Z is C1-C2alkylene, R1 and R10 are H; R2, R4, R7 and R9, independently of one another, are halogen, H, -OCN, or -OH; R3 and R8, independently of one another, are H, -OCN or -OH; R5 and R6, independently of one anther, are H, -OCN or -OH; and R11 and R12 are halogen, wherein at least one of aromatic rings A and B is substituted by at least one cyanato group. In a particularly preferred compound, Z is C1- C2alkylene, R1, R5, R6 and R10 are H; R2, R4, R7 and R9, independently of one another, are halogen or H; R3 and R8 are -OCN; and Rl 1 and R12 are halogen. A most preferred compound is characterized by Z being methylene, R1, R2, R4, R5, R6, R7, R9 and R10 being H; R3 and R8 being a cyanato group and R11 and R12 being chlorine. The novel compound is prepared by reacting, in a first reaction, an aromatic compound substituted with a mono-, di- or tri-haiogen containing aldehyde, acetal or hemiacetal or corresponding alcohol, in the presence of an acid, preferably a highly acidic environment having a pH of less than about 3, to produce an aromatic compound containing at least two rings linked by the halogen-substituted residue of the aldehyde, acetal or hemiacetal. In a second reaction, the resulting aromatic compound is contacted by a basic compound, such as potassium hydroxide, and an organic non-polar solvent, such as methanol, to remove at least one halogen group to produce an aromatic compound wherein the at least two rings are linked by a group containing an unsaturated group. The aforementioned reactions are described in greater detail in U.S. Pat. Nos. 3,856,566, 4,110.541, and 4,117,018, which are each incorporated herein by reference. In a third reaction, at least some of the hydroxyl groups of the aromatic compound resulting from the second reaction are converted into cyanato-groups via reaction with a cyanogenhalide, such as cyanogen chloride or cyanogen bromide, via a known reaction as described in U.S. Pat. ^^5^,149,863..(which is incorporated herein by reference) to produce the desired final product. The resulting produc can be used as is or recrystallized in purer form. The amount of cyanogenhalide should be sufficient to react with all of the hydroxyl groups of the aromatic compound resulting from th Suitable aromatic compounds for this invention contain one or more aromatic rings having at least one hydroxyl group. The aromatic rings can be further substituted with alky! and/or halogen groups. Examples of suitable aromatic compounds are phenol, phenyl phenol, cresol, xylenii, carvacol, thymol, naphthol, disubstituted naphthol, anthrol, phenanthroi, pyrocatechol, resorcinol, hydroquinone , and bicyclic hydroxyl-containing compounds linked by alkylene, carbonyl, oxyl, and/or sulfonyl groups and halogenated, such as bromine, fluorine and chlorine, corresponding compounds. It is anticipated that halogen substitution would improve the flame retardancy of molded articles resulting from such halogenated compounds and compositions thereof. Mixtures of said aromatic compounds can be used as well as mixtures with minor amounts of non-aromatic alcohols. Phenol is a particularly preferred aromatic compound for use herein. Suitable halogen-containing aldehydes, acetals and hemiacetals include mono- and polyhalogenated compounds, such as fiuoropropanal or fluoroacetaldehyde, bromopropanal or bromoacetaidehyde, chloroethanal, chloropropanai or chloroacetaldehyde, 2-chloro-1-ethoxy ethanol, 2-fluoro-1 -ethoxy ethano!, 2-bromo-1 -ethoxy ethanol, difiuoropropanal or difluroacetaldehyde, dibromopropanal or dibromoacetaldehyde, dichloroethanal, dichloropropanal or dichloroacetaldehyde, 2,2-dichloro-1 -ethoxy ethanol, 2,2-difiuoro-1 -ethoxy ethanol, 2,2-dibromo-1 -ethoxy ethanol, trifluoropropanal or trifluoroacetaldehyde, tribromopropanal or tribromoacetaldehyde (bromal), trichloroethanal, trichloropropanal or trichloroacetaldehyde (chloral), 2,2,2-trichloro-1-ethoxy ethanol, 2,2,2-trifluoro-1-ethoxy ethanol, 2,2,2-tribromo-1-ethoxy ethanol. Trichloroethanal and 2,2,2-trichloro-1-ethoxy ethanol are particularly preferred. required to produce one mole of cyclotrimerized prepolymer product. A composition containing the novel compound described above can be cyclotrimerized in conventional fashion to produce a prepolymer wherein up to about 60% of the cyanato groups in the overall composition have been trimerized. More preferably, the prepolymer is characterized by having about 10 to 40%, more preferably about 20 to 30% of the cyanato groups trimerized. The novel compound described above forms a solid resin having a softening point in the range of 70 to 80°C. The inventive compound described above can be used alone or combined with other mono- and polycyanato-group containing compounds to form thermosetting resin compositions. The additional cyanato-group containing compounds can be halogenated in order to improve flame retardancy. The additional cyanato-group containing compounds can be combined with the inventive compound described above in order to modify the glass transition temperature and improve processing of the overall composition provided that the overall objective is achieved of obtaining a molded article having low peak heat release characteristics. Applicants have found, for example, that the addition of aromatic monocyanates, such as naphthol cyanate, phenylphenol cyanate and the monocyanate of the inventive compounds disclosed herein, preferably up to about 40% by weight depending upon the type of selected aromatic cyanate reduces the glass transition temperature of the overall thermosetting composition without significantly increasing the peak heat release rate of the resulting molded articles and impacting mechanical properties. The inventive compound described above can also be combined with other thermal curable monomers and reactive compounds, such as epoxies, bismaleimides, polyimides, polyesters, epoxy-acrylates, urethane-acrylates, diailyl phthalates, spiropyrane, and phenol provided the molded article retains the desired low heat release characteristics. The composition can also contain a curing catalyst, such as imidazole compounds, tertiary amines or organometallic compounds. Organometallic compounds such as cobalt octanate, zinc octanate, cobalt naphthalenate, or zinc naphthenate are preferred. The curing reaction can also be further accelerated by the addition of small amounts of phenols, such as bisphenol A, bisphenol F, bisphenol S, or p-nonylpheno(. The composition can also further contain a customary additive or filler such as alumina, aluminum hydroxide, antimony tri- or pentaoxide, zinc oxide, titanium dioxide, silica powder, quartz powder, glass powder, ceramic microballons or mixtures thereof. A preferred thermosetting composition or resin varnish contains at least 15%, more preferably 50 to 100%, most preferably 60 to 99% by weight of the inventive compound and/or its corresponding prepoiymer with the balance being solvent, additional mono- and polycyanato-group containing compounds, thermal curable or reactive compounds other than cyanate esters, cure accelerators and customary additives and fillers. Suitable solvents include ketones, such as methyl ethyl ketone, methyl isobutyl ketone, aromatic hydrocarbons, such as toluene or xylene, ethers, such as dioxane, tetrahydrofuran or ethylene glycol monomethyl ether, alcohols, such as methanol, ethanol, isopropyl alcohol, amides, such as dimethylformamide or dimethylacetamide and mixtures thereof. Aromatic hydrocarbons and ketones are preferred. For casting applications, a thermosetting composition described above is heated to a molten state to produce a prepoiymer composition before casting into a mold, and then allowed to cure at an elevated temperature. For bonding applications, a resin varnish or molten prepoiymer composition is applied to the surfaces to be bonded, and then allowed to cure under heat and pressure. Prepregs are produced by impregnating a suitable substrate with a resin varnish containing the inventive compound and drying the impregnated substrate. The impregnation apparatus can be of conventional design. Examples of substrates used in the preparation of prepregs include carbon fiber, glass fiber substrates, such as glass cloth or glass non-woven fabric, cellulosic substrates, such as kraft paper or cotton linter paper, synthetic fiber fabric such as aramide cloth or aramide nonwoven fabric. Composite laminates can be produced using different types of substrates in combination. The compounds and compositions disclosed herein can be utilized to produce aircraft interior section in known fashion, such as the interiors disclosed in U.S. Pat. No. 5,714,419, assigned on its face to Fiberite, Inc., which is incorporated herein by reference. Microcombustion data for molded articles containing the inventive compounds were obtained using a pyrolysis-combustion flow calorimeter developed by the Federal Aviation Administration ("FAA"). In the test, 1 to 5 mg sample is placed in a 10-mm-long by 2.5-mm outside diameter quartz tube. A linear 10°C/second heating rate is used. The pyrolysis products are swept from the pyrolyzer by flowing nitrogen gas stream through a heated Uansier line and mixed with excess oxygen prior to entering a high-temperature lurnace to force complete combustion of the pyrolyzate. The heat release by combustion is calculated from the oxygen consumption using a universal value of 13.1 kJ of heat released per gram of diatomic oxygen consumed. The data of peak heat release rate and total heat release are obtained from the calorimeter on triplicate samples of each material measured. The flammability resistance for the resin was also measured according to the Ohio State University heat release test (OSU test). This test measures the amount of heat evolved in a period of 2 minutes (C) as well as the rare of heat evolution at the peak (BJ when a given test sample is exposed to radiation under specified conditions. OSU test results in a curve of heat evolution versus time. The rate of heat is increased at specified conditions according to the Federal Aviation Administration (FAA). This corresponds to the impingement of a sample at rate of 3.5 watts/cm2. The volatiles are completely burnt by a small flame and the heat evolved is recorded as a function of time. Glass fabric does not contribute to heat evolution. C3alkyl), -COR, -N02, -NR"R", wherein R, R" and R" are H or Cl-C3alkyl; or Rl and R2 together and/or R2 and R3 together, and/or R9 and RIO together, and/or R8 and R9 together, independently of one another, form one or more aromatic rings or five or six membered cycloalkylene that can each be substituted with Cl-C4alkyl or halogen; Rll and R12, independently of one another are H, phenyl, Cl-C4alkyl or halogen; wherein at least one of aromatic rings A and B or at least one of the aromatic rings or the five or six membered ring formed by Rl and R2 and/or R2 and R3 and/or R9 and RIO and/or R8 and R9 is substituted by at least one cyanato group. Several examples are set forth below to illustrate the nature of the invention and method for carrying it out. However, the invention should not be considered as being limited to the details thereof. All parts are in parts by weight unless otherwise indicated. Example 1: l,l-dichIoro-2,2-bis(4-cyanatophenyl)ethylene is prepared as follows. A 4-necked 3-L flask, equipped with a mechanical stirrer, a nitrogen inlet, and thermometer, is charged with 83% sulfuric acid (640 g). To this sulfuric acid, phenol (354 g) is added at 20°C. Chloral (200 g) in an additional funnel is added dropwise to the phenolic stirring mixture. The reaction temperature is maintained below 30°C. After the addition, the mixture is allowed to stir at room temperature for 18 hours, before water (640 g) is added. The resulting mixture is filtered and washed with more water to afford l,l,l-trichloro-2,2-bis(4-hydroxyphenyl)ethane (423 g) as white solids. A 4-necked 5-liter flask, equipped with a mechanical stirrer, a thermometer, and a condenser, is charged with methanol (800 g). Potassium hydroxide (440 g) is added in portions to the methanol solution. After the addition, the solution is cooled to 20"C. To this stirring solution, l,l,l-trichloro-2,2-bis(4-hydroxyphenyl)ethane (420 g) is added in portions. The reaction temperature is kept below 40°C. After the addition, the temperature is raised to 50°C and maintained for 2.5 hours. The reaction mixture is cooled to 20°C and neutralized with 25% HC1 solution. After the neutralization, the mixture is heated to reflux and water (480 g) is added. The mixture is allowed to cool to the room temperature. The precipitates are filtered and dried to afford 1,1 -dichloro-2,2-bis(4-hydroxyphenyl}ethene as white solids with slight tan color. A 4-necked 5-L flask, equipped with a mechanical stirrer, a thermometer, and an additional funnel, is charged with methyl isobutyl ketone (1500 g), 1,1-dichloro-2,2-bis{4-hydroxyphenyljethene (320 g), and cyanogen bromide (270 g). The resulting solution is cooled to -20°C with a dry ice/acetone bath. To the stirring solution, triethylamine (240 g) in the additional funnel is added dropwise. The reaction temperature is maintained below-20°C. After the addition, the resulting mixture is allowed to warm up to 0°C and quenched with dilute HCI aqueous solution. The organic layer is washed further with water a few times and concentrated under vacuum to afford 370 g of amber liquid, which solidifies as light tan color solids. Example 2 1 ,i-dibromo-2,2-bis(4-cyanatophenyl)ethylene is prepared as follows. A 4-necked 3-L flask, is equipped with a mechanical stirrer, a nitrogen inlet, and thermometer, is charged with 83% sulfuric acid (640 g) and phenol (354 g). To the resulting milky mixture, tribromo-acetaldehyde (380 g) in an additional funnel is added dropwise. The reaction temperature is maintained below 30°C. After the addition, the mixture is allowed to stir at the room temperature for 18 hours, before water (640 g) is added. The resulting mixture is filtered and washed with more water to afford 1,1,1 -thbromo-2,2-bis(4-hydroxyphenyi)ethane. A 4-necked 5-liter flask, equipped with a mechanical stirrer, a thermometer, and a condenser, is charged with methanol (800 g). Potassium hydroxide (440 g) is added in portions to the methanol solution. After the addition, the solution is cooled to 2Q°C. To this stirring solution, 1,1,1-tribromo-2,2-(4-hydroxyphenyl)ethane (420 g) is added in portions. The reaction temperature is kept below 40°C. After the addition, the temperature is raised to 50°C and kept for 2 hours. The reaction mixture is cooled to room temperature and neutralized with 25 % HCI solution. After the neutralization, the mixture is heated to reflux and water is added. The mixture is allowed to cool to the room temperature. The precipitates formed are filtered and dried to afford 1,1-dibromo-2,2-bis(4-hydroxyphenyl)ethene. A 4-necked 5-L flask, equipped with a mechanical stirrer, a thermometer, and an additional funnel, is charged with methyl isobutyl ketone (1500 g), 1,1-dibromo-2,2-bis(4-hydroxypheny!)ethene (420 g), and cyanogen bromide (270 g). The resulting solution is cooled to -20°C with a dry ice/acetone bath. To the stirring solution, triethylamine (240 g) in the additional funnel is added dropwise. The reaction temperature is maintained below-20°C. After the addition, the resulting mixture is allowed to warm up to 0"C and quenched with dilute HCI aqueous solution. The organic layer is washed further with water several times and concentrated under vacuum to afford the desired product. laminates are weighed and the resin content is determined to be about 35 %. Ex. 2a is the sandwich panel with glass fabric and ex. 2b is the sandwich panel with carbon fabric. Comp. 2a is made from phenol formaldehyde resin and glass fabric. Comp. 2b is made from phenol formaldehyde resin and carbon fabric. The OSU test is carried out on each sample in triplicate- The average of three value is shown in Table 2. WE CLAIM: 1. A cyanate ester having flame resistant properties represented by formula (I): least one of the aromatic rings or the five or six membered ring formed by Rl and R2 and/or R2 and R3 and/or R9 and RIO and/or R8 and R9 is substituted by at least one cyanato group. 2. The compound as claimed in claim 1 wherein Z is Cl-C2alkylene; Rl and RIO are H; R2, R4, R7 and R9, independently of one another, are halogen, H, -OCN, or -OH; R3, R5, R6 and R8, independently of one another, are H, -OCN or -OH; Rl 1 and R12 are halogen; and at least one of aromatic rings A and B is substituted by at least otie cyanato group. 3. The compound as claimed in claim 1 wherein Z is Cl-C2alkylene; Rl, R5, R6 and RIO are H; R2, R4, R7 and R9, independently of one another, are halogen or H; Rl 1 and R12 are halogen; and R3 and R8 are -OCN. 4. The compound as claimed in claim 3 wherein Z is methylene, Rl, R2, R4, R5, R6, R7, R9 and RIO are H; R3 and R8 are -OCN; and Rll and R12 are chlorine. 5. A prepolymer comprising a cycfotrimerized reaction product of [one or more than one] cyanate esters as educts wherein at least one of said educts is a compound as claimed in claim 1, whereby the prepolymer in the form of an triazine network of cyclotrimerized reaction products is obtained in conventional manner upon heating and/or in the presence of a curing agent. 6. The prepolymer as claimed in claim 5 wherein up to about 60% of the cyanato groups in the overall composition are trimerized as a part of the cyclotrimerized reaction product. 7. A composition comprising a) a compound as claimed in claim 1 or a cyclotrimerized reaction product of cyanate esters as claimed in claim 5 wherein at least one of said cyanate esters is the compound as claimed in claim 1 and b) a solvent. 8. A composition comprising a) a compound as claimed in claim 1 or a cyclotrimerized reaction product of cyanate esters as claimed in claim 5, and b) a mono- or polycyanate ester different from component a). 9. The composition as claimed in claim 8 wherein component b) is at least one halogen- substituted or unsubstituted aromatic monocyanate ester. 10. A composition comprising a) a compound as claimed in claim 1 or a cyclotrimerized reaction product of cyanate esters as claimed in claim 5, and b) a thermally curable monomer or oligomer other than a cyanate ester. 11. A composition comprising a) at least 15% by weight of the overall composition of a compound as claimed in claim 1 or a cyclotrimerized reaction product of cyanate esters as claimed in claim 5, and with the balance of the composition being at least one of components (b) to (g) as follows: b) solvent, c) additional mono- and polycyanato-group containing compounds, d) thermal curable or reactive compounds other than cyanate esters, e) cure catalysts and/or accelerators 14. The process as claimed in claim 12 wherein the aromatic compound reacted with the halogen-containing aldehyde, acetal or hemiacetal in step (a) is selected from phenol, chlorophenol, dichlorophenol, cresol, xylenil, czirvacol, thymol, naphthol, anthrol, phenanthrol, pyrocatechol, resorcinol, chloror^sorcinol, dichlororesorcinol, hydroquinone, chlorohydroquinone, dichlorohydroquinone, trichlorohydroquinone, dinaphthol, chlorodiriapthol, dichlorodinaphthol and mixtures thereof. 15. The process as claimed in claim 12 wherein the reaction mixture in Step (a) further comprises a minor amount of a non-aromatic alcohol. 16. A cured article such as herein described obtained after curing a curable composition as claimed in any one of claims 7 to 11 having a peak heat release rate of less than about 10 Joule/g-°K as measured using a pyrolysis-combustion flow calorimeter developed by the Federal Aviation Administration. 17. A cured article such as herein described obtained after curing a curable composition as claimed in anyone of claims 7 to 11 having a peak heat release rate of less than about 25 Joule/g-°K as measured by the Ohio State University heat release test.

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in-pct-2001-1191-che abstract.pdf

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in-pct-2001-1191-che description (compelet)- duplicate.pdf

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in-pct-2001-1191-che pct others.pdf

in-pct-2001-1191-che pct search report.pdf

in-pct-2001-1191-che pct.pdf

in-pct-2001-1191-che petition.pdf