FLAME-RETARDANT, HIGH TEMPERATURE RESISTANT THERMOSETS ON THE BASIS OF NAPHTHALENE-BASED EPOXY RESINS AND CYANATE ESTERS

Abstract

The embodiments relate to a polymerisable thermoset composition having improved flame retardant properties, a polymerised thermoset having improved flame retardant properties, a process for manufacturing the polymerised thermoset, and use of the polymerisable thermoset composition to produce lightweight construction components, preferably carbon fibre composites (CFRP), and a lightweight construction component, preferably carbon fibre composite (CFRP), containing the polymerised thermoset.

Claims

1. A polymerisable thermoset composition, comprising: a) a di- or polyfunctional organic cyanate ester resin; b) a naphthalene based epoxy resin; and c1) at least one phosphorus-containing phenol; and/or c2) at least one phosphorus-containing epoxy and at least one diamine; wherein the polymerisable thermoset composition comprises at least one high-performance thermoplast.

2. The polymerisable thermoset composition according to claim 1, wherein the phosphorus-containing phenol is a (hydrocarbyl-)phosphonic acid ester and/or contains 9-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide as the structural unit.

3. The polymerisable thermoset composition according to claim 1, wherein the phosphorus-containing epoxy is a (hydrocarbyl-)phosphonic acid ester and/or contains 9-dihydroz-9-oxa-10-phosphaphenanthrene-10-oxide as the structural unit.

4. The polymerisable thermoset composition according to claim 1, wherein the phosphorus-containing phenol contains one of the following structural units: ##STR00019## wherein: n is a number between 1 and 1000, o is a number between 0 and 4, p is a number between 0 and 4, r is a number between 0 and 3, R.sup.1 is a C.sub.1-C.sub.10 alkyl, R.sup.2 is a C.sub.1-C.sub.10 alkyl, and R.sup.3 is a C.sub.1-C.sub.10 alkyl; or ##STR00020## wherein: s is a number between 1 and 1000, t is a number between 0 and 4, and R.sup.4 is a C.sub.1-C.sub.10 alkyl.

5. The polymerisable thermoset composition according to claim 1, wherein the phosphorus-containing epoxy contains the following structural unit (III): ##STR00021## wherein a is a number between 0 and 4, b is a number between 0 and 4, c is a number between 0 and 3, d is a number between 0 and 3, e is a number between 1 and 1000, f is a number between 1 and 1000, R.sup.10 is a C.sub.1-C.sub.10 alkyl, R.sup.11 is a C.sub.1-C.sub.10 alkyl, R.sup.12 is a C.sub.1-C.sub.10 alkyl or hydrogen, R.sup.13 is a C.sub.1-C.sub.10 alkyl or hydrogen, R.sup.14 is a C.sub.1-C.sub.10 alkyl or hydrogen, R.sup.15 is a C.sub.1-C.sub.10 alkyl or hydrogen, R.sup.16 is a C.sub.1-C.sub.10 alkyl, R.sup.17 is a C.sub.1-C.sub.10 alkyl, R.sup.18 is a C.sub.1-C.sub.10 alkyl or hydrogen, and R.sup.19 is a C.sub.1-C.sub.10 alkyl or hydrogen.

6. The polymerisable thermoset composition according to claim 1, wherein the di- or polyfunctional organic cyanate ester resin is a cyanate having formula (IV): ##STR00022## wherein R.sup.1, R.sup.2 and R.sup.3 are each independently hydrogen or C.sub.1-C.sub.10 alkyl, and n represents an integer from 0 to 20.

7. The polymerisable thermoset composition according to claim 1, wherein the naphthalene-based epoxy resin represents a polymeric naphthalene-based epoxy resin.

8. The polymerisable thermoset composition according to claim 1, wherein the at least one high-performance thermoplast is selected from the group comprising polysulfones (PSU), polyetherimide (PEI), polysulfone (PSU), polycarbonate (PC), silicone rubber and mixtures thereof.

9. The polymerisable thermoset composition according to claim 1, wherein the high-performance thermoplast is present in the form of core-shell particles.

10. The polymerisable thermoset composition according to claim 9, wherein the shell of the core-shell particles contains an epoxy resin, a cyanate ester or mixtures thereof, and the core contains a silicone rubber.

11. A polymerised thermoset constituting a reaction product of the polymerisable thermoset composition according to claim 1.

12. A polymerised thermoset according to claim 11, wherein the thermoset has a glass transition temperature from 285 C. to 300 C. and/or curing temperature in a range from 100 to 180 C.

13. A process for manufacturing a polymerised thermoset, comprising the steps of: i) providing a polymerisable thermoset composition according to claim 1; ii) polymerising the polymerisable thermoset composition at temperatures of from 100 to 180 C.

14. Use of the polymerisable thermoset composition according to claim 1 to manufacture lightweight construction components.

15. A lightweight construction component containing the polymerised thermoset according to claim 11.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0089] A more complete understanding of the subject matter may be derived by referring to the detailed description and claims when considered in conjunction with the following figures, wherein like reference numbers refer to similar elements throughout the figures.

[0090] FIG. 1 shows a DMA spectrum of the composition PT15/HP4710/HFC-X=(1/0.5)/0.07, which further contains 9.1% by weight Albidur EP 2240A.

[0091] FIG. 2 shows a DMA spectrum of the composition PT15/HP4710/HFC-X=(1/0.5)/0.07, which further contains 13.8% by weight Albidur EP 5341.

[0092] FIG. 3 shows a DMA spectrum of the composition PT15/HP4710/HFC-X=(1/0.5)/0.07, which further contains 9.1% by weight Albidur EP 5341.

[0093] FIG. 4 shows a DMA spectrum of the composition PT15/HP4710/HFC-X=(1/0.5)/0.07, which further contains 9.1% by weight Albidur XP10669.

DETAILED DESCRIPTION

[0094] The following detailed description is merely exemplary in nature and is not intended to limit the disclosed embodiments or the application and uses thereof. Furthermore, there is no intention to be bound by any theory presented in the preceding background detailed description.

[0095] The embodiments disclosed herein relate to a polymerisable thermoset composition comprising: a) a di- or polyfunctional organic cyanate ester resin, b) a naphthalene based epoxy resin, and c1) at least one phosphorus-containing phenol and/or c2) at least one phosphorus-containing epoxy and at least one diamine.

[0096] The term polymerisable means that under suitable conditions, such as elevated temperature or with the aid of catalysts, the individual components of the composition can be polymerised.

[0097] The term thermoset refers to a prepolymer that can no longer be reshaped after it has been polymerised and cured.

[0098] A requirement of the embodiment is that the polymerisable thermoset composition contains c1) at least one phosphorus-containing phenol and/or c2) at least one phosphorus-containing epoxy and at least one diamine.

[0099] The phosphorus-containing phenol is preferably a (hydrocarbyl-)-phosphonic acid ester and/or contains 9-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide as a structural unit.

[0100] More preferably, the phosphorus-containing phenol contains one of the following structural units (I) and (II) wherein

##STR00010## [0101] n is a number between 1 and 1000, preferably between 200 and 500, [0102] o is a number between 0 and 4, preferably between 0 and 2, more preferably 0 or 1, and is most preferably 0, [0103] p is a number between 0 and 4, preferably between 0 and 2, more preferably 0 or 1, and is most preferably 0, [0104] r is a number between 0 and 3, preferably between 0 and 2, more preferably 0 or 1, and is most preferably 0, [0105] R.sup.1 is a C.sub.1-C.sub.10 alkyl, [0106] R.sup.2 is a C.sub.1-C.sub.10 alkyl, and [0107] R.sup.3 is a C.sub.1-C.sub.10 alkyl

[0108] or wherein

##STR00011## [0109] s is a number between 1 and 1000, preferably between 100 and 600, [0110] t is a number between 0 and 4, preferably between 0 and 2, more preferably 0 or 1 and most preferably is 0, and [0111] R.sup.4 is a C.sub.1-C.sub.10 alkyl.

[0112] In one embodiment, the polymerisable thermoset composition contains a compound containing structural unit (I), wherein n is a number between 1 and 1000, o, p and r are each independently a number between 0 and 4, and R.sup.1, R.sup.2 and R.sup.3 are each independently a C.sub.1-C.sub.10 alkyl.

[0113] The polymerisable thermoset composition may for example contain a compound containing structural unit (I), wherein n is a number between 200 and 500, o, p and r are each independently a number between 0 and 4, and R.sup.1, R.sup.2 and R.sup.3 are each independently a C.sub.1-C.sub.10 alkyl.

[0114] For the purposes of the present embodiment, the term alkyl refers to a radical from a saturated aliphatic group, including linear alkyl groups and branched alkyl groups, wherein the linear alkyl groups and branched alkyl groups are preferably not substituted.

[0115] The bond on the salicylate group of the structural unit according to formula (I) with the next monomer unit is preferably in the ortho position to the OH group.

[0116] The polymerisable thermoset composition preferably contains a compound containing structural unit (I) wherein n is a number between 1 and 1000, o, p and r are each independently a number between 0 and 4, and R.sup.1, R.sup.2 and R.sup.3 are each independently a C.sub.1-C.sub.10 alkyl, and the bond on the salicylate group of the structural unit according to formula (I) with the next monomer unit is in the ortho position to the OH group.

[0117] For example, the polymerisable thermoset composition contains a compound containing structural unit (I) wherein n is a number between 200 and 500, o, p and r are each independently a number between 0 and 4, and R.sup.1, R.sup.2 and R.sup.3 are each independently a C.sub.1-C.sub.10 alkyl, and the bond on the salicylate group of the structural unit according to formula (I) with the next monomer unit is in the ortho position to the OH group.

[0118] In one embodiment, the polymerisable thermoset composition contains a compound containing structural unit (I) wherein n is a number between 1 and 1000, o, p and r are each 0 or 1, and R.sup.1, R.sup.2 and R.sup.3 are each independently a C.sub.1-C.sub.10 alkyl. For example, the polymerisable thermoset composition contains a compound containing structural unit (I) wherein n is a number between 1 and 1000, o, p and r are each 0 or 1, and R.sup.1, R.sup.2 and R.sup.3 are each independently a C.sub.1-C.sub.10 alkyl, and the bond on the salicylate group of the structural unit according to formula (I) with the next monomer unit is in the ortho position to the OH group.

[0119] In one embodiment, the polymerisable thermoset composition contains a compound containing structural unit (I) wherein n is a number between 200 and 500, o, p and r are each 0 or 1, and R.sup.1, R.sup.2 and R.sup.3 are each independently a C.sub.1-C.sub.10 alkyl. For example, the polymerisable thermoset composition contains a compound containing structural unit (I) wherein n is a number between 200 and 500, o, p and r are each 0 or 1, and R.sup.1, R.sup.2 and R.sup.3 are each independently a C.sub.1-C.sub.10 alkyl, and the bond on the salicylate group of the structural unit according to formula (I) with the next monomer unit is in the ortho position to the OH group

[0120] For example, the polymerisable thermoset composition contains a compound containing structural unit (I) wherein n is a number between 1 and 1000 and o, p and r are each 0. For example, the polymerisable thermoset composition contains a compound containing structural unit (I) wherein n is a number between 1 and 1000 and o, p and r are each 0, and the bond on the salicylate group of the structural unit according to formula (I) with the next monomer unit is in the ortho position to the OH group.

[0121] For example, the polymerisable thermoset composition contains a compound containing structural unit (I) wherein n is a number between 200 and 500 and o, p and r are each 0. For example, the polymerisable thermoset composition contains a compound containing structural unit (I) wherein n is a number between 200 and 500 and o, p and r are each 0, and the bond on the salicylate group of the structural unit according to formula (I) with the next monomer unit is in the ortho position to the OH group.

[0122] For example, the polymerisable thermoset composition contains a compound containing structural unit (II), wherein s is a number between 1 and 1000, t is a number between 0 and 4 and R.sup.4 is a C.sub.1-C.sub.10 alkyl.

[0123] For example, the polymerisable thermoset composition contains a compound containing structural unit (II), wherein s is a number between 100 and 600, t is a number between 0 and 4 and R.sup.4 is a C.sub.1-C.sub.10 alkyl.

[0124] The polymerisable thermoset composition may for example contain a compound containing structural unit (II), wherein s is a number between 1 and 1000, t is a number between 0 and 2 and R.sup.4 is a C.sub.1-C.sub.10 alkyl.

[0125] The polymerisable thermoset composition may for example contain a compound containing structural unit (II), wherein s is a number between 100 and 600, t is a number between 0 and 2 and R.sup.4 is a C.sub.1-C.sub.10 alkyl.

[0126] The polymerisable thermoset composition may for example contain a compound containing structural unit (II), wherein s is a number between 1 and 1000, t is a number between 0 and 1 and R.sup.4 is a C.sub.1-C.sub.10 alkyl.

[0127] The polymerisable thermoset composition may for example contain a compound containing structural unit (II), wherein s is a number between 100 and 600, t is a number between 0 and 1 and R.sup.4 is a C.sub.1-C.sub.10 alkyl.

[0128] The polymerisable thermoset composition may for example contain a compound containing structural unit (II), wherein s is a number between 1 and 1000 and t=zero.

[0129] The polymerisable thermoset composition may for example contain a compound containing structural unit (II), wherein s is a number between 100 and 600 and t=zero.

[0130] The following compounds are examples of the phosphorus-containing phenol

##STR00012##

[0131] wherein n is a number between 1 and 1000, preferably between 200 and 500 or

##STR00013##

[0132] wherein s is a number between 1 and 1000, preferably between 100 and 600.

[0133] For example, the phosphorus-containing epoxy is a (hydrocarbyl-)-phosphonic acid ester and/or contains 9-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide as a structural unit. The phosphorus-containing epoxy preferably contains

[0134] 9-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide as the structural unit.

[0135] The phosphorus-containing epoxy preferably contains the following structural unit (III) wherein:

##STR00014## [0136] a is a number between 0 and 4, preferably between 0 and 2, more preferably 0 or 1 and most preferably is 0 [0137] b is a number between 0 and 4, preferably between 0 and 2, more preferably 0 or 1 and most preferably is 0, [0138] c is a number between 0 and 3, preferably between 0 and 2, more preferably 0 or 1 and most preferably is 0, [0139] d is a number between 0 and 3, preferably between 0 and 2, more preferably 0 or 1 and most preferably is 0, [0140] e is a number between 1 and 1000, preferably between 200 and 500, [0141] f is a number between 1 and 1000, preferably between 50 and 200, [0142] R.sup.10 is a C.sub.1-C.sub.10 alkyl, [0143] R.sup.11 is a C.sub.1-C.sub.10 alkyl, [0144] R.sup.12 is a C.sub.1-C.sub.10 alkyl or hydrogen, preferably methyl or hydrogen, and most preferably hydrogen, [0145] R.sup.13 is a C.sub.1-C.sub.10 alkyl or hydrogen, preferably methyl or hydrogen, and most preferably hydrogen, [0146] R.sup.14 is a C.sub.1-C.sub.10 alkyl or hydrogen, preferably methyl or hydrogen, and most preferably hydrogen, [0147] R.sup.15 is a C.sub.1-C.sub.10 alkyl or hydrogen, preferably methyl or hydrogen, and most preferably hydrogen, [0148] R.sup.16 is a C.sub.1-C.sub.10 alkyl, [0149] R.sup.17 is a C.sub.1-C.sub.10 alkyl, [0150] R.sup.18 is a C.sub.1-C.sub.10 alkyl or hydrogen, preferably methyl or hydrogen, and most preferably hydrogen, and [0151] R.sup.19 is a C.sub.1-C.sub.10 alkyl or hydrogen, preferably methyl or hydrogen, and most preferably hydrogen.

[0152] The methylene groups in structural unit (III) are preferably each located at the ortho position to the oxygen atom.

[0153] In one embodiment, in structural unit (III) [0154] a is either 0 or 1, preferably 0, [0155] b is either 0 or 1, preferably 0, [0156] c is either 0 or 1, preferably 0, [0157] d is either 0 or 1, preferably 0, [0158] e is a number between 1 and 1000, preferably between 200 and 500, [0159] f is a number between 1 and 1000, preferably between 50 and 200, [0160] R.sup.10 is a C.sub.1-C.sub.10 alkyl, [0161] R.sup.11 is a C.sub.1-C.sub.10 alkyl, [0162] R.sup.12 is methyl or hydrogen, preferably hydrogen, [0163] R.sup.13 is methyl or hydrogen, preferably hydrogen, [0164] R.sup.14 is methyl or hydrogen, preferably hydrogen, [0165] R.sup.15 is methyl or hydrogen, preferably hydrogen, [0166] R.sup.16 is a C.sub.1-C.sub.10 alkyl, [0167] R.sup.17 is a C.sub.1-C.sub.10 alkyl, [0168] R.sup.18 is methyl or hydrogen, preferably hydrogen, [0169] R.sup.19 is methyl or hydrogen, preferably hydrogen.

[0170] For example, in structural unit (III) [0171] a is either 0 or 1, preferably 0, [0172] b is either 0 or 1, preferably 0, [0173] c is either 0 or 1, preferably 0, [0174] d is either 0 or 1, preferably 0, [0175] e is a number between 1 and 1000, preferably between 200 and 500, [0176] f is a number between 1 and 1000, preferably between 50 and 200, [0177] R.sup.10 is a C.sub.1-C.sub.10 alkyl, [0178] R.sup.11 is a C.sub.1-C.sub.10 alkyl, [0179] R.sup.12 is methyl or hydrogen, preferably hydrogen, [0180] R.sup.13 is methyl or hydrogen, preferably hydrogen, [0181] R.sup.14 is methyl or hydrogen, preferably hydrogen, [0182] R.sup.15 is methyl or hydrogen, preferably hydrogen, [0183] R.sup.16 is a C.sub.1-C.sub.10 alkyl, [0184] R.sup.17 is a C.sub.1-C.sub.10 alkyl, [0185] R.sup.18 is methyl or hydrogen, preferably hydrogen, [0186] R.sup.19 is methyl or hydrogen, preferably hydrogen

[0187] The methylene groups in structural unit (III) are each located at the ortho position to the oxygen atom.

[0188] For example, in structural unit (III) a, b, c and e are each 0, e is a number between 1 and 1000, f is a number between 1 and 1000 and R.sup.12, R.sup.13, R.sup.14, R.sup.15, R.sup.18 and R.sup.19 are each hydrogen. For example in structural unit (III), a, b, c and e are each 0, e is a number between 1 and 1000, f is a number between 1 and 1000, and R.sup.12, R.sup.13, R.sup.14, R.sup.15, R.sup.18 and R.sup.19 are each hydrogen, and the methylene groups are each located on the ortho position to the oxygen atom.

[0189] For example, in structural unit (III) a, b, c and e are each 0, e is a number between 200 and 500, f is a number between 50 and 200 and R.sup.12, R.sup.13, R.sup.14, R.sup.15, R.sup.18 and R.sup.19 are each hydrogen. For example, in structural unit (III) a, b, c and e are each 0, e is a number between 200 and 500, f is a number between 50 and 200 and R.sup.12, R.sup.13, R.sup.14, R.sup.15, R.sup.18 and R.sup.19 are each hydrogen, and the methylene groups are each located on the ortho position to the oxygen atom.

[0190] The following compound is an example of the phosphorus-containing epoxy:

##STR00015##

[0191] wherein e is a number between 1 and 1000, preferably between 50 and 200, and

[0192] wherein f is a number between 1 and 1000, preferably between 50 and 200,

[0193] and the methylene groups are each located on the ortho position to the oxygen atom.

[0194] Such an epoxy represents an additional epoxy in the resin mixture, and for this reason a diamine is also used as a curing agent.

[0195] The diamine is typically an aromatic diamine, preferably selected from the group comprising 2,4-diaminotoluene, 2,6-diaminotoluene, 3,5-diethyl-2,4-diaminotoluene, 3,5-diethyl-2,6-diaminotoluene, and primary mono-, di-, tri- or tetra-alkyl substituted 4,4-diaminodiphenyl methanes, 6-methyl-2,4-bis(methylthio)phenylene-1,3-diamine and 2-methyl-4,6-bis(methylthio)phenylene-1,3-diamine.

[0196] If the polymerisable thermoset composition according to the embodiment should contain diamine, the total quantity of diamine relative to the polymerisable thermoset composition is 0.25 to 5.0% by weight, preferably 0.1 to 2.0% by weight or 0.2 to 1.5% by weight. Alternatively, the polymerisable thermoset composition contains the aromatic diamine, preferably in a quantity of for example 0.4 to 1.2% by weight or 0.5 to 1.0% by weight.

[0197] In one embodiment, component c2) is present and component c1) is not present.

[0198] In a further, preferred embodiment, component c1) is present and component c2) is not present. In this embodiment, a diamine is normally not needed to function as an additional curing component. The polymerisable thermoset composition of this embodiment preferably does not contain a diamine.

[0199] The total quantity of components c1) and c2) relative to the polymerisable thermoset composition is typically in the range from 5.5 to 20% by weight, preferably in the range from 6.0 to 15% by weight, and more preferably in the range from 6.5 to 12% by weight.

[0200] Since components c1) and/or c2) function as curing agents, curing agents and/or catalysts with harmful health effects do not need to be used.

[0201] The polymerisable thermoset composition according to the embodiment preferably does not contain any curing agents and/or catalysts with harmful health effects.

[0202] A further requirement of the present embodiment is that the polymerisable thermoset composition comprises a di- or polyfunctional organic cyanate ester resin.

[0203] The choice of di- or polyfunctional organic cyanate ester resin is not critical. In theory, any at least difunctional cyanate ester resin can be used. However, it is preferable if di- or polyfunctional organic cyanate ester resins having formula (IV) are used:

##STR00016##

[0204] wherein R.sup.1, R.sup.2 and R.sup.3 are each independently hydrogen or C.sub.1-C.sub.10 alkyl, and n represents an integer from 0 to 20.

[0205] In one embodiment of the present embodiment, the di- or polyfunctional organic cyanate ester resin is a cyanate having formula (IV), wherein R.sup.1, R.sup.2 and R.sup.3 are independently hydrogen or C.sub.1-C.sub.10 alkyl and n represents an integer from 0 to 10. The di- or polyfunctional organic cyanate ester resin is preferably a cyanate having formula (IV), wherein R.sup.1, R.sup.2 and R.sup.3 are independently hydrogen or C.sub.1-C.sub.10 alkyl, and n represents an integer from 1 to 5.

[0206] The methylene group in formula (IV) may be at the ortho position to the cyanate group in each case. The methylene group in formula (IV) is preferably located in the ortho position to the cyanate group in each case.

[0207] For example, the di- or polyfunctional organic cyanate ester resin is a cyanate having formula (IV), wherein R.sup.1, R.sup.2 and R.sup.3 are hydrogen or C.sub.1-C.sub.10 alkyl, and n represents an integer from 0 to 20. Alternatively, the di- or polyfunctional organic cyanate ester resin is a cyanate having formula (IV), wherein R.sup.1, R.sup.2 and R.sup.3 are hydrogen or C.sub.1-C.sub.10 alkyl, and n represents an integer from 0 to 10. The di- or polyfunctional organic cyanate ester resin is preferably a cyanate having formula (IV), wherein R.sup.1, R.sup.2 and R.sup.3 are hydrogen or C.sub.1-C.sub.10 alkyl, and n represents an integer from 1 to 5. The di- or polyfunctional organic cyanate ester resin is for example a cyanate having formula (IV), wherein R.sup.1, R.sup.2 and R.sup.3 are hydrogen or C.sub.1-C.sub.10 alkyl, and n represents an integer from 1 to 5, and the methylene group is in the ortho position to the cyanate group in each case.

[0208] In one embodiment of the present embodiment, the di- or polyfunctional organic cyanate ester resin is a cyanate having formula (IV);

##STR00017##

[0209] wherein R.sup.1, R.sup.2 and R.sup.3 are hydrogen and n represents an integer from 0 to 20.

[0210] For example, the di- or polyfunctional organic cyanate ester resin is a cyanate having formula (IV), wherein R.sup.1, R.sup.2 and R.sup.3 are hydrogen and n represents an integer from 1 to 10. The di- or polyfunctional organic cyanate ester resin is preferably a cyanate having formula (IV), wherein R.sup.1, R.sup.2 and R.sup.3 are hydrogen and n represents an integer from 1 to 5.

[0211] In one embodiment of the present embodiment, the di- or polyfunctional organic cyanate ester resin is a cyanate having formula (IV), wherein R.sup.1, R.sup.2 and R.sup.3 are hydrogen and n represents 1, 2 or 3. For example, the di- or polyfunctional organic cyanate ester resin is a cyanate having formula (IV), wherein R.sup.1, R.sup.2 and R.sup.3 are hydrogen and n represents 1, 2 or 3, and the methylene is located in the ortho position to the cyanate group in each case.

[0212] The cited di- or polyfunctional organic cyanate ester resins having formula (I) may also be used as monomers or as prepolymers, alone or in mixtures with each other.

[0213] The polymerisable thermoset composition preferably comprises the di- or polyfunctional organic cyanate ester resin in a quantity from for example 50 to 80% by weight, or 55 to 75% by weight, relative to the total weight of the composition. Alternatively, the polymerisable thermoset composition comprises the di- or polyfunctional organic cyanate ester resin preferably in in a quantity from for example 55 to 70% by weight, or 60 to 65% by weight relative to the total weight of the composition.

[0214] A further requirement of the present embodiment is that the polymerisable thermoset composition comprises a naphthalene-based epoxy resin.

[0215] In theory, any naphthalene-based epoxy resin can be used. Preferably, however, naphthalene-based epoxy resins that have four glycidyl ether functionalities per repeating unit are used. This high number of glycidyl ether functionalities is particularly favourable for obtaining a thermoset with high crosslinking density.

[0216] In one embodiment of the present embodiment, the naphthalene-based epoxy resin is a polymeric naphthalene-based epoxy resin.

[0217] For example, the naphthalene-based epoxy resin is a naphthalene-based epoxy resin having formula (V):

##STR00018##

[0218] wherein n represents an integer from 1 to 50.

[0219] The naphthalene-based epoxy resin is preferably a naphthalene-based epoxy resin having formula (V), wherein n represents an integer from 1 to 40 or 1 to 20. Alternatively, the naphthalene-based epoxy resin is a naphthalene-based epoxy resin having formula (V), wherein n represents an integer from 1 to 10 or 1 to 5.

[0220] The cited naphthalene-based epoxy resins having formula (V) may also be used as monomers or as prepolymers, alone or in mixtures with each other.

[0221] The polymerisable thermoset composition comprises the naphthalene-based epoxy resin preferably in a quantity of for example 19.9 to 48% by weight, or 24.8 to 43.5% by weight relative to the total weight of the composition. Alternatively, the polymerisable thermoset composition comprises the naphthalene-based epoxy resin preferably in a quantity of for example 29.6 to 43.8% by weight or 29.6 to 35% by weight, relative to the total weight of the composition.

[0222] To obtain a polymerised thermoset with high thermal stability, it is advantageous if the polymerisable thermoset composition contains the di- or polyfunctional organic cyanate ester resin and the naphthalene-based epoxy resin in a certain weight ratio.

[0223] Therefore, the polymerisable thermoset composition preferably contains the di- or polyfunctional organic cyanate ester resin and the naphthalene-based epoxy resin in a weight ratio (weight/weight) from 10:1 to 1:1. For example, the polymerisable thermoset composition contains the di- or polyfunctional organic cyanate ester resin and the naphthalene-based epoxy resin in a weight ratio (weight/weight) from 7:1 to 1:1 or from 5:1 to 1:1. In one embodiment of the present embodiment, the polymerisable thermoset composition contains the di- or polyfunctional organic cyanate ester resin and the naphthalene-based epoxy resin in a weight ratio (weight/weight) of about 2:1.

[0224] In one embodiment of the present embodiment, the naphthalene-based epoxy resin has an EEW from 100 to 500 g/eq, preferably from 125 to 300 g/eq and most particularly preferably from 150 to 200 g/eq.

[0225] In order to obtain a polymerised thermoset with high impact resistance, it is advantageous if the polymerisable thermoset composition comprises at least one high-performance thermoplast, also called an impact modifier.

[0226] For the purposes of the present embodiment, a high-performance thermoplast is a thermoplast with which the impact resistance of the polymerised thermosets may be modified, preferably increased.

[0227] In one embodiment of the present embodiment, the polymerisable thermoset composition therefore comprises a) a di- or polyfunctional organic cyanate ester resin, b) a naphthalene based epoxy resin, and c1) at least one phosphorus-containing phenol, and/or c2) at least one phosphorus-containing epoxy and at least one diamine, and additionally, d) at least one high-performance thermoplast.

[0228] For example, the polymerisable thermoset composition comprises at least one high-performance thermoplast, also called an impact modifier, selected from the group comprising polysulfones (PSU), for example polyethersulfone (PES) and polyphenylsulfone (PPSU), polyetherimide (PEI), polysulfone (PSU), polycarbonate (PC), silicone rubber and mixtures thereof.

[0229] The impact modifier may also be present in the form of core-shell particles, in the present case preferably containing at least one high-performance thermoplast, as described above, typically as the core.

[0230] The polymerisable thermoset composition comprises for example silicone rubber as the high-performance thermoplast, preferably in the form of core-shell particles.

[0231] The shell of the core-shell particles typically consists of a polymer matrix containing an epoxy resin, a cyanate ester or mixtures thereof. The core contains, preferably consists of, a different polymer, selected for example from the group comprising silicone rubber, nitrile rubber, styrene-butadiene rubber, polyisoprene rubber, polybutadiene, butyl rubber, fluoroelastomers, etc., and mixtures thereof, for example silicone rubber.

[0232] For example, the core contains, preferably consists of, silicone rubber, and the shell contains, preferably consists of, an epoxy resin. Alternatively, the core contains, preferably consists of, silicone rubber, and the shell contains, preferably consists of, a cyanate ester.

[0233] In the case of an epoxy resin, the EEW (epoxy equivalent weight) thereof is typically between 200 and 350 g/eq.

[0234] The weight ratio between the core and shell of the core-shell particles may be for example 25:75 to 75:25, preferably 30:70 to 60:40, more preferably 35:65 to 50:50.

[0235] Examples of suitable core-shell particles are Albidur EP 5341, Albidur EP 2240A and Albidur XP 10669. More details about the properties and use of these additives are provided in Fibre-reinforced composites based on epoxy resins modified with elastomers and surface-modified silica nanoparticles, Journal of Material Science 2013 (Stephan Sprenger).

[0236] The polymerisable thermoset composition comprises the at least one high-performance thermoplast preferably in a quantity from for example 0.1 to 20% by weight, or 0.5 to 15% by weight relative to the total weight of the composition. Alternatively, polymerisable thermoset composition comprises the at least one high-performance thermoplast preferably in a quantity from for example 1.0 to 18% by weight or 2.0 to 14% by weight relative to the total weight of the composition.

[0237] In the case of core-shell particles, the weight specification refers to the total mass of the core-shell particle.

[0238] In order to obtain a polymerised thermoset with high impact resistance, it is advantageous if the polymerisable thermoset composition contains the mixture of di- or polyfunctional organic cyanate ester resin and naphthalene-based epoxy resin and the at least one high-performance thermoplast in a certain weight ratio.

[0239] For example, the polymerisable thermoset composition contains the mixture of di- or polyfunctional organic cyanate ester resin and naphthalene-based epoxy resin and the at least one high-performance thermoplast in a weight ratio (weight/weight) from 100:1 to 3:1. In one embodiment of the present embodiment, the polymerisable thermoset composition contains the mixture of di- or polyfunctional organic cyanate ester resin and naphthalene-based epoxy resin and the at least one high-performance thermoplast in a weight ratio (weight/weight) from 50:1 to 3:1 or from 40:1 to 5:1. The polymerisable thermoset composition preferably contains the mixture of di- or polyfunctional organic cyanate ester resin and naphthalene-based epoxy resin and the at least one high-performance thermoplast in a weight ratio (weight/weight) from 33:1 to 10:1.

[0240] Still more auxiliary agents and additives may be added to the polymerisable thermoset composition. For example, lubricants such as fatty acid esters, metal soaps thereof, fatty acid amides and silicone compounds, antiblocking agents, inhibitors, stabilisers against hydrolysis, light, heat and discolouration, flame protection agents, dyes, pigments, inorganic or organic filler materials to enhance mechanical and/or dielectric properties and reinforcing agents may be added to the polymerisable thermoset composition. For example, fibrous reinforcing agents such as inorganic fibres that are manufactured according to the state of the art may be added as reinforcing agents. The polymerisable thermoset composition may contain carbon fibres, for example.

[0241] Based on the advantages offered by the polymerisable thermoset composition, the present embodiment also relates to a polymerised thermoset that represents a reaction product of the polymerisable thermoset composition as described herein.

[0242] The polymerised thermoset offers the advantage that it has good thermal resistance. In particular, the polymerised thermoset has improved thermal resistance compared with pure epoxy resins. Furthermore, the polymerised thermoset has a high glass transition temperature. In particular, the polymerised thermoset has a higher glass transition temperature than previously known CE/epoxy combinations.

[0243] The polymerised thermoset according to the embodiment typically has a glass transition temperature from 285 C. to 300 C.

[0244] In addition or alternatively thereto, the polymerised thermoset according to the embodiment has a curing temperature in a range from 100 to 180 C. The polymerised thermoset according to the embodiment preferably has a curing temperature in a range from 125 to 175 C.

[0245] In one embodiment of the present embodiment, the polymerised thermoset according to the embodiment has a density in a range from 1.20 to 1.35 g/cm.sup.3 and preferably in a range from 1.25 to 1.30 g/cm.sup.3.

[0246] In addition or alternatively thereto, the polymerised thermoset according to the embodiment has a water absorption capacity in a range from 1.2 to 1.35% by weight, based on the total weight of the polymerised thermoset.

[0247] In one embodiment of the present embodiment, the polymerised thermoset according to the embodiment has a decomposition temperature in a range from 350 to 400 C. and preferably in a range from 360 to 380 C.

[0248] A vertically suspended sample of the polymerised thermoset according to the embodiment that has been set alight preferably goes out within not more than 30 seconds, and release no burning droplets of molten plastic, as determined in the to the Vertical Burn Test according to DIN EN 60695-11-10.

[0249] A further aspect of the present embodiment relates to a process for manufacturing a polymerised thermoset, as described herein. The process comprises the steps of: providing a polymerisable thermoset composition as described herein, and polymerising the polymerisable thermoset composition at temperatures in a range from 100 to 180 C.

[0250] The polymerisable thermoset composition according to the embodiment may generally be provided by mixing the di- or polyfunctional organic cyanate ester resin, the naphthalene-based epoxy resin, the at least one phosphorus-containing phenol and/or the at least one phosphorus-containing epoxy and at least one diamine and optional additives, such as the at least one high-performance thermoplast. In one embodiment of the present embodiment, the polymerisable thermoset composition according to the embodiment is poured into a preferred mould or hollow space and is then polymerised in situ. Polymerisation takes place at temperatures in a range from 100 to 180 C. or from 125 to 175 C., for example at approximately 150 C., preferably for a total of 1 to 10 hours or for 2 to 5 hours. Polymerisation may be carried out in a single, continuous process or in multiple different and chronologically separate steps. Polymerisation is preferably carried out in a single, continuous process.

[0251] In one embodiment of the present embodiment, the process for manufacturing a polymerised thermoset comprises a post-curing step iii), in which the polymerised thermoset is post-cured. Post-curing takes place at temperatures in a range from 200 to 280 C. or from 200 to 250 C., for example at about 220 C., preferably for a total of 1 to 10 hours or for 2 to 5 hours. Post-curing may be carried out in a single, continuous process or in multiple different and chronologically separate steps. Post-curing is preferably carried out in a single, continuous process.

[0252] In view of the advantages offered by the polymerised thermoset according to the embodiment, the present embodiment also relates to the use of the polymerisable thermoset composition as described herein to manufacture lightweight construction components, preferably carbon fibre composites (CFRP). For example, the polymerised thermoset is used as a lightweight construction component in load-bearing lightweight construction elements that are exposed to thermal stresses, and are particularly exposed to elevated temperatures, for example temperatures higher than 200 C. In particular, the polymerised thermoset is used as a lightweight construction component in aerospace applications. For example, the polymerised thermoset is used as a lightweight construction component on satellites, rockets, aircraft such as passenger aeroplanes or helicopters, in rail vehicles such as trains, water vehicles such as passenger ships, or road vehicles such as cars.

[0253] A further aspect of the present embodiment therefore relates to a lightweight construction component, preferably carbon fibre composite (CFRP), which contains the polymerised thermoset as described herein.

[0254] As was explained earlier, polymerised thermosets may be obtained on the basis of the polymerisable thermoset composition according to the embodiment, which products are resistant to high temperatures and have a high glass transition temperature and good impact resistance. The polymerisable thermoset composition according to the embodiment may also be cured at moderate temperatures, and at the same time has improved resistance to hydrolysis. The polymerisable thermoset composition according to the embodiment also contains no curing agents and/or catalysts that are hazardous to health.

Examples

[0255] Methods

[0256] a.) DSC measurements were taken with the aid of the DSC Q2000 device made by TA Instruments. The spectra were recorded using the Thermal Advantage Release 5.4.0 software and analysed using the Universal Analysis 2000, Version 4.5A software produced by TA Instruments. The heating rate was 5 K/min at a temperature from 20 C. to 350 C.

[0257] b.) TGA measurements were taken with the aid of the TGA Q5000 device made by TA Instruments. The spectra were recorded using the Thermal Advantage Release 5.4.0 software and analysed using the Universal Analysis 2000, Version 4.5A software produced by TA Instruments. The heating rate was 10 K/min, at a temperature from 20 C. to 1000 C. Each measurement was carried out both in an inert gas atmosphere (N2) and in an oxygen atmosphere (ambient air).

[0258] c.) DMA and rheology measurements Viscosity measurements and determination of glass transition temperatures (Tg) of the materials were carried out using the Advanced Rheometric Expansion System (ARES) rheometer manufactured by Rheometric Scientific. For analysis, the software Rheometric Scientific, Version V6.5.8 was used. The heating rates were 3 K/min in all cases. Glass transition corresponds to the maximum of the tan(6) function.

[0259] d.) UL-94 flammability test. The flammability properties of the materials were determined in accordance with DIN EN 60695-11-10, using the Vertical Burn Test. The flame treatment time lasted for up to 60 sec.

[0260] 2. Materials Used:

[0261] Primaset PT15 (available from Lonza) is an oligo(3-methylene-1,5-phenylcyanate).

[0262] Epiclon HP-4710 (available from DIC Corporation) is an oligo(1,1,5,5-bis-(2,7-diglycidyloxy-1-naphthyl) methane) with an EEW of 170 g/eq.

[0263] Epiclon HFC-X (available from DIC Corporation) is an organophosphorous phenolic resin with an OH equivalent weight of 428 g/eq and a phosphorus content of 10.4% by weight.

[0264] XP3775 (available from Schill+Seilacher Struktol GmbH) is a DOPO-modified Novolak with a phosphor content of 7.5% by weight and a EEW <2000 g/eq.

[0265] Fyrol PMP (available from ICL) is a poly(m-phenylmethylphosphonate) with a phosphor content of 17.5%.

[0266] Core-Shell Particles:

[0267] Albidur EP 5341 is a dispersion of an elastomer with high-performance capabilities in a cycloaliphatic epoxy resin with a silicone rubber content of 40% by weight and a EEW von 225-255 g/eq.

[0268] Albidur EP 2240A is a dispersion of an elastomer with high-performance capabilities in an epoxy resin based on bisphenol A with a silicone rubber content of 40% by weight and a EEW von 290-315 g/eq.

[0269] Albidur XP10669 s a dispersion of an elastomer with high-performance capabilities in a cyanate ester consisting of 4,4-ethylidene diphenyldicyanate. The silicone rubber content is 40% by weight and the content of 4,4-ethylidene diphenyldicyanate is 60% by weight.

[0270] Presentation of the Materials:

[0271] The resins Primaset PT15, Epiclon HP 47110, the corresponding organophosphorous modifier and the corresponding impact modifier are weighed in together and then melted in a convection oven and homogenised with a dispersing agent at 80 C. Then, the mixture is first degassed in the vacuum oven for 2 hours at 80 C. and then degassed for 1 hour at 110 C. The hot thermoset mixture is then poured into an aluminium casting mould that has been preheated to 130 C., and undergoes the following heating cycle:

[0272] 1.) 130 C..fwdarw.160 C. (ramp=2K/min)

[0273] 2.) Maintain at constant temp. 160 C. for 4 hours

[0274] 3.) 160 C..fwdarw.30 C. (ramp=3K/min)

[0275] 4.) free-standing post-curing: 230 C. for 4 hours

[0276] The results from the DSC tests show that the cured thermoset has a glass transition temperature from 285 C. to 300 C.

[0277] The characterisation of the flame retardant properties and of the DMA tests is described in the following.

[0278] For this purpose, blends of the composition PT15/HP4710/FSM were prepared. The mixture ratio of PT15/HP4710 was 1/0.5.

TABLE-US-00001 Flame Wt. proportion UL-94 retardant FSM/wt % evaluation.sup.1) T.sub.g/ C. T.sub.onset/ C. HFC-X 2.9 Burns 294 269 HFC-X 4.8 Burns 291 264 HFC-X 9.1 V-0.sup.2) 281 249 Fyrol PMP 2.9 Burns 306 281 Fyrol PMP 4.8 Burns 288 260 Fyrol PMP 6.5 V-1.sup.3) 293 267 Fyrol PMP 9.1 V-1.sup. 283 254 .sup.1)The flame treatment time did not exceed 60 s. All test samples could not be flamed for at least 12 sec, so all received the evaluation V-0 for t < 12 s. .sup.2)V-0 A vertically suspended test sample that was alight went out within 10 sec without releasing burning droplets of melted plastic. .sup.3)V-1: A vertically suspended test sample that was alight went out within 30 sec without releasing burning droplets of melted plastic.

[0279] 1.) The flame treatment time did not exceed 60 s. All test samples could not be flamed for at least 12 sec, so all received the evaluation V-0 for t<12 s.

[0280] 2.) V-0 A vertically suspended test sample that was alight went out within 10 sec without releasing burning droplets of melted plastic.

[0281] 3.) V-1: A vertically suspended test sample that was alight went out within 30 sec without releasing burning droplets of melted plastic.

[0282] The impact resistance modifications using core-shell particles are described below. For this, PT15/HP4710/HFC-X/Modifier blends were used. The composition of (PT15/HP4710)/HFC-X was in the ratio of: (1/0.5)/0.07. The quantity of impact modifier is listed in the following table.

TABLE-US-00002 Wt. proportion Modifier Modifier/wt % Tg/ C. Tonset/ C. Albidur EP2240A 9.1 285 258 Albidur EP5340A 9.1 289 264 Albidur EP5340A 13.8 284 257 Albidur XP10669 9.1 291 265