Cardanol based curing agent for epoxy resins compositions

Abstract

The present invention relates to new compounds based on cardanol based which can be used as curing agents, compositions comprising the novel compounds, the manufacture of such compounds and of such compositions, and the use of these 5 compositions, in particular in a potting process in electrical and electronic components and devices.

Claims

1. A compound comprising a substituted cardanol, wherein the substituted cardanol comprises a hydrocarbon chain substituted with at least one group comprising at least one amide group and at least one amino-functional group comprising an active hydrogen linked to an amine group; and at least one of the hydrogens on the aromatic ring of the cardanol is substituted with at least one group comprising at least one amino-functional group comprising an active hydrogen linked to an amine group, such that the aromatic ring is directly substituted with said at least one amino-functional group.

2. The compound of claim 1, wherein a group of the at least one amino-functional group substituted on the hydrocarbon chain and the at least one amino-functional group substituted on the aromatic ring comprises a secondary amine.

3. The compound of claim 2, wherein each group comprising an active hydrogen linked to an amine group further comprises an alkyl group, an aryl group, a heteroaryl group, a cycloalkyl group, or a heterocycloalkyl group.

4. The compound of claim 1, wherein one or more of the at least one amino-functional group substituted on the hydrocarbon chain and the at least one amino-functional group substituted on the aromatic ring further comprises at least one ether group.

5. The compound of claim 4, wherein the group further comprising at least one ether group comprises a polyether segment.

6. A curable composition comprising the compound of claim 1 and an amine reactive resin.

7. The curable composition of claim 6, wherein the amine reactive resin is an epoxy resin.

8. An electrical device comprising a potted component including a cured form of the curable composition of claim 6.

9. An electronic device comprising a potted component including a cured form of the curable composition of claim 6.

10. A process for preparing a curing agent, the process comprising: reacting a cardanol with maleic anhydride in the presence of a catalyst; and in the presence of formaldehyde or paraformaldehyde and a catalyst, reacting a reaction product of the cardanol and maleic anhydride with at least one compound comprising at least one of a primary amine group and a secondary amine group, at least one of the hydrogens on the aromatic ring of the resulting substituted cardanol being substituted with at least one group comprising at least one amino-functional group comprising an active hydrogen linked to an amine group, such that the aromatic ring is directly substituted with said at least one amino-functional group.

11. The process of claim 10, wherein the at least one of a primary amine group and a secondary amine group further comprises an ether group.

12. The process of claim 11, wherein the ether group is comprised in a polyetheramine.

13. A process for preparing an article or a material, the process comprising: forming a mixture including an amine reactive resin and a curing agent, the curing agent comprising a substituted cardanol, wherein the substituted cardanol comprises a hydrocarbon chain substituted with at least one group comprising at least one amide group and at least one amino-functional group comprising an active hydrogen linked to an amine group, and the substituted cardanol comprises an aromatic ring, at least one of the hydrogens on the aromatic ring being substituted with at least one group comprising at least one amino-functional group comprising an active hydrogen linked to an amine group, such that the aromatic ring is directly substituted with said at least one amino-functional group; and curing the mixture.

14. A material obtained by the process of claim 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

(1) The present invention relates to a compound comprising a substituted cardanol, wherein the hydrocarbon chain of the cardanol is substituted with at least one group having at least one amino-functional group having an active hydrogen linked to an amine group and at least one amide group; and the aromatic ring of the cardanol is substituted with at least one group having at least one amino-functional group having an active hydrogen linked to an amine group.

(2) In another preferred embodiment of the compound of the invention, the group having at least one active hydrogen linked to an amine group comprises a secondary amine.

(3) In another preferred embodiment of the compounds of the invention, each group comprising at least one active hydrogen linked to an amine group further comprises a group selected from alkyl, aryl, heteroaryl, cycloalkyl and heterocycloalkyl. More preferably, the compounds of the invention further comprise a group selected from alkyl and hetero cycloalkyl.

(4) In a preferred embodiment of the compound of the invention, the group having at least one active hydrogen linked to an amine group further comprising at least one ether group.

(5) In a preferred embodiment of the compound of the invention, the group further comprising at least one ether group comprises a polyether segment.

(6) The invention further relates to a curable composition comprising anyone of the compounds of the invention and an amine reactive resin.

(7) The amine reactive resin of the curable composition might also react with —OH groups.

(8) Preferably, the amine active resin is an epoxy resin. More preferably, the epoxy resin has on average at least one epoxy group per molecule, preferably at least one glycidyl group per molecule.

(9) In a further embodiment, the invention relates to the use of a compound of the invention for curing a composition comprising an amine reactive resin. Preferably an epoxy resin. More preferably the epoxy resin has on average at least one epoxy group per molecule, preferably at least one glycidyl group per molecule.

(10) In a preferred embodiment, anyone of the compounds of the invention can be used in any curable composition in the described embodiments comprising an amine reactive resin.

(11) More preferred epoxy resins are those epoxy resins having 1.8 epoxy groups per molecule.

(12) Commercially available epoxy resins are suitable for being cured with the compounds of the invention. Preferably, the commercially available epoxy resins suitable for the invention are based on bisphenol A, bisphenol F or mixtures thereof.

(13) In another embodiment, the invention relates to the use of the composition comprising the compound of the invention for potting electrical and electronic components or devices.

(14) In another embodiment, the invention relates to the use of the compound of the invention in a composition for potting electrical and electronic components or devices.

(15) In another embodiment, the invention relates to a process for preparing the compounds of the invention.

(16) In another embodiment, the invention relates to a process for the preparation of anyone of the compounds of the invention comprising the steps of a) reacting the cardanol with maleic anhydride in the presence of a catalyst; b) Reacting the reaction product of step a) with at least one compound having at least one primary or secondary amine group in the presence of formaldehyde and a catalyst.

(17) In a preferred embodiment, the primary or secondary amine further comprises an ether group, preferably a polyether segment.

(18) In a preferred embodiment, the primary or secondary amine further comprises an ether group is a polyetheramine.

(19) In another preferred embodiment, the primary and/or secondary amine group further comprises a group selected from alkyl, aryl, heteroaryl, cycloalkyl and heterocycloalkyl.

(20) In a further preferred embodiment, the catalyst of step a) comprises a metal complex. Preferably, the metal is selected from the group consisting of a transition metal, preferably the transition metal complex is a transition metal complex solution. More preferably, the transition metal is Cobalt or Manganese. Most preferably the catalyst is a cobalt napthenate.

(21) In another preferred embodiment, the catalyst of step b) is an acid compound, preferably oxalic acid.

(22) In a further embodiment, the invention relates to a process for preparing an article or a material, comprising the steps of: a. mixing an epoxy resin having on average at least one one epoxy group per molecule, preferably at least one glycidyl group per molecule, with the curing agent of anyone of claims 1 to 5 b. curing the mixture of step a.

(23) In a further embodiment, the invention relates to an article obtained by a process comprising the steps of: a. mixing an epoxy resin having on average at least one one epoxy group per molecule, preferably at least one glycidyl group per molecule, with the curing agent of anyone of claims 1 to 5 b. curing the mixture of step a.

(24) In a further embodiment, the invention relates to a material obtained by a process comprising the steps of: a. mixing an epoxy resin having on average at least one glycidyl group per molecule with the curing agent of anyone of claims 1 to 5 b. curing the mixture of step a.

(25) Preferred compounds having primary and/or secondary amine groups used in the process of the invention are aliphatic amines, cycloaliphatic amines, heterocyclic amines, aromatic amines.

(26) Accordingly, the compound comprising at least a primary or a secondary amine may further comprise a group selected from alkyl, aryl, heteroaryl, cycloalkyl and heterocycloalkyl.

(27) Preferably the compounds comprising at least a primary or a secondary amine are selected from the group consisting of N-aminoethylpiperazine; diethylenetriamine; triethylenetetramine (TETA); tetraethylenepentamine; 2-methylpen tamethylene; 1,3-pentanediamine; trimethylhexamethylene diamine; a polyamide; a polyamidoamine and combination of thereoftrimethylolpropane tris[poly(propylene glycol), amine terminated] ether, 2-(1-piperazinyl)ethylamine, 3-aminomethyl-3,5,5-trimethylcyclohexylamine, 3,6,9,12-tetraazatetradecane-1,14-diamine, tetraethylenepentamine and triethylenetetramine, 3,6-diazoctanethylenediamine, 3,6,9-triazaundecamethylenediamine, 1,3-bis(aminomethyl)benzene, 1,3-bis(aminomethyl)cyclohexane, 5-diethyl toluene-2,4-diamine and 3,5-diethyl toluene-2,6-diamine (mixture of the two isomers), 2,2′-(ethylenedioxy)bis(ethylamine), 1,6-diamino-2,2,4(2,4,4)-trimethylhexane, N′-(3-aminopropyl)-N,N-dimethylpropane-1,3-diamine, 4,4′-diaminodicyclohexylmethane, 1,2-cyclohexanediamine and mixtures thereof.

(28) Preferred compounds having at least a primary or a secondary amine group further comprising at least one ether group are polyetheramines. Preferred polyetheramines of the invention preferably comprise at least one oxyethylene diamine segment, oxyethylene triamine segment or polyoxyethylene diamine segment. Polyetheramines of the invention preferably comprise at least one propylene oxide segment, ethylene oxide segment or a mixture of both.

(29) Preferred polyetheramine used in the present invention are commercially available under the trademark JEFFAMINE from Huntsman Corporation, Houston, Tex. such as, JEFFAMINE D-230, JEFFAMINE D-400, JEFFAMINE D-2000, JEFFAMINE T-403, JEFFAMINE ED-600, JEFFAMINE ED-900, JEFFAMINE ED-2001, JEFFAMINE EDR-148, JEFFAMINE XTJ-509, JEFFAMINE T-3000, JEFFAMINE T-5000, and combinations thereof. Preferred polyetheramines of the invention are JEFFAMINE® D-230.

(30) Cured composition in this invention may further comprise inorganic and/or organic fillers. Suitable inorganic fillers include barium sulfate, silica, aluminum oxide, calcium oxide, magnesium oxide, sodium oxide, potassium oxide, iron oxide, titanium oxide, other oxides or mixtures thereof. Other suitable fillers include silica-gels, calcium silicates, calcium nitrate, calcium phosphates, calcium molybdates, calcium carbonate, calcium hydroxide, fumed silica, clays such as bentonite, aluminium trihydrates, magnesium dihydrates, glass microspheres, hollow glass microspheres, polymeric microspheres, and hollow polymeric microspheres. Organic fillers such as aramid fibers and polyolefin fibers such as polyethylene fibers can be used in the curable composition.

(31) The curable composition can contain any suitable amount of the filler. It may contains 0.01 to 50 weight percent filler based on a total weight of the curable composition.

(32) The compounds of the inventions can be used for curing a composition comprising an amine reactive resin, preferably an epoxy resin, more preferably, the epoxy resin has on average at least one glycidyl group per molecule.

(33) The invention further relates to a process for preparing the compounds of the invention. The process comprises the steps of reacting the cardanol and/or bisphenol with at least one compound having at least one primary or secondary amine group and one compound having at least one primary or secondary amine group further comprising an ether group in the presence of formaldehyde and a catalyst.

(34) The invention further relates to a process for preparing an article or material comprising the step of mixing an amine reactive resin, preferably an epoxy resin, with the compound of the invention and curing the mixture.

(35) Another object of the invention are the articles or materials produced by the process comprising the step of mixing an amine reactive resin with the compound of the invention and curing the mixture.

(36) The present invention is explained in more details by the following non-limiting examples.

EXAMPLES

(37) The phenalkamine of the invention were synthetized analogously to the synthesis procedure given in the U.S. Pat. No. 6,262,148 B1 and Journal of Polymer Science, Part A: Polymer Chemistry, Vol. 52, pp, 472-480, [2014], Wiley Periodicals, Inc.

(38) The reaction of cardanol with maleic anhydride was performed analogously to Balguade et al. (published in Progress in Organic Coatings, 2016).

Example 1

(39) Preparation of Intermediate 1 Obtained by Using Cardanol and Maleic Anhydride.

(40) Three liter reaction flask is charged with the following ingredients:

(41) 1600.00 g of Cardanol

(42) 392.24 g of Maleic anhydride

(43) 10 g of 5-10% solid solution of cobalt naphthenate as a catalyst

(44) In a three liter reaction flask with a water cooled reflux condenser, 1600 g of cardanol and 392.24 g of maleic anhydride were added under stirring. 10 g of cobalt naphthenate was added to the mixture under stirring. This mixture was heated slowly to 190° C. under continuous stirring for 2:5 hours duration.

Example 2.1

(45) Preparation of Cardanol Based Polyamide by Using Intermediate 1 and TETA (Triethylenetetramine).

(46) One liter reaction flask was charged with the following ingredients:

(47) 228 g of hydrolyzed malenized cardanol

(48) 130 g of TETA (Triethylenetetramine)

(49) 43 g of DETA (Diethylenetriamine)

(50) 100 g of SOFA (Soya Acid Fatty Acid)

(51) 0.2 g of oxalic acid (catalyst)

(52) In a one liter reaction flask with a water cooled reflux condenser, 228 g of hydrolyzed malenized cardanol and 130 g of TETA, 43 g of DETA and 100 g of SOFA were added under stirring. 0.2 g of oxalic acid were further added under stirring. This mixture was heated slowly to 210° C. under continuous stirring for 2.5 hours duration. At this temperature, a clear mixture was obtained which indicating a complete reaction took place. The residual water present in mixture was removed by applying vacuum of 650 mm/Hg for 1 hour duration to the system.

Example 2.2

(53) Preparation of Cardanol Based Polyamide by Using Intermediate 1 and TEPA (Tetraethylenepentamine).

(54) One liter reaction flask was charged with the following ingredients:

(55) 228 g of hydrolyzed malenized cardanol

(56) 145 g of TEPA (Tetraethylenepentamine)

(57) 43 g of DETA (Diethylenetriamine)

(58) 100 g of SOFA (Soya Acid Fatty Acid)

(59) 0.2 g of oxalic acid (catalyst)

(60) The above same procedure used for the synthesis of cardanol based polyamide by using hydrolyzed malenized cardanol and TEPA (Tetraethylenepentamine).

Example 2.3

(61) Preparation of Cardanol Based Polyamide by Using Intermediate 1 and AEP (Aminoethylpiperazine).

(62) One liter reaction flask was charged with the following ingredients:

(63) 228 g of hydrolyzed malenized cardanol

(64) 147 g of AEP (Aminoethylpiperazine)

(65) 43 g of DETA (Diethylenetriamine)

(66) 100 g of SOFA (Soya Acid Fatty Acid)

(67) 0.2 g of oxalic acid (catalyst)

(68) The above same procedure used for the synthesis of cardanol based polyamide by using hydrolyzed malenized cardanol and AEP (Aminoethylpiperazine).

Example 3.1

(69) Preparation of Polyamide-Phenalkamine Based Curing Agent by Using Intermediate 1, TETA (Triethylenetetramine) and Paraformaldehyde.

(70) In one liter reaction flask following ingredients was charged to prepare a polyamide-phenalkamine based curing agent by using TETA:

(71) 180 g of hydrolyzed malenized cardanol

(72) 5 g of Paraformaldehyde

(73) 102 g of TETA (Triethylenetetramine)

(74) 35 g of DETA (Diethylenetriamine)

(75) 78 g of SOFA (Soya Acid Fatty Acid)

(76) 0.2 g of oxalic acid (catalyst)

(77) All the above additive were charged in one liter reaction flask with a water cooled reflux condenser under continuous stirring and heated slowly to 180° C. with continuous stirring for 2.5 hours duration. After completion of reaction, residual water present in mixture is removed by applying vacuum of 650 mm/Hg for 1 hour duration to the system.

Example 3.2

(78) Preparation of Polyamide-Phenalkamine Based Curing Agent by Using Intermediate 1, TEPA (Tetraethylenepentamine) and Paraformaldehyde.

(79) In one liter reaction flask following ingredients was charged to prepare a polyamide-phenalkamine based curing agent by using TEPA:

(80) 180 g of hydrolyzed malenized cardanol

(81) 5 g of Paraformaldehyde

(82) 119 g of TEPA (Tetraethylenepentamine)

(83) 35 g of DETA (Diethylenetriamine)

(84) 78 g of SOFA (Soya Acid Fatty Acid)

(85) 0.2 g of oxalic acid (catalyst)

(86) The above same procedure was used for the synthesis of polyamide-phenalkamine by using TETA.

Example 3.3

(87) Preparation of Polyamide-Phenalkamine Based Curing Agent by Using Intermediate 1, AEP (Aminoethylpiperazine) and Paraformaldehyde.

(88) In one liter reaction flask following ingredients was charged to prepare a polyamide-phenalkamine based curing agent by using AEP:

(89) 180 g of hydrolyzed malenized cardanol

(90) 5 g of Paraformaldehyde

(91) 112 g of AEP (Aminoethylpiperazine)

(92) 35 g of DETA (Diethylenetriamine)

(93) 78 g of SOFA (Soya Acid Fatty Acid)

(94) 0.2 g of oxalic acid (catalyst)

(95) The above same procedure was used for the synthesis of polyamide-phenalkamine by AEP.

Example 4.1

(96) Preparation of Polyetheramine Modified Polyamide-Phenalkamine by Using Cardanol Based Polyamide Prepared from TETA, Paraformaldehyde and Polyetheramine.

(97) In one liter reaction flask following ingredients was charged to prepare a polyetheramine modified polyamide-phenalkamine based curing agent:

(98) 250 g of Cardanol based polyamide prepared from TETA

(99) 11.60 g of Paraformaldehyde

(100) 125 g of Jeffamine D 230 polyetheramine

(101) 0.2 g of oxalic acid (catalyst)

(102) All the above additive were charged in three liter reaction flask with a water cooled reflux condenser under continuous stirring and heated slowly to 120° C. with continuous stirring for 2.5 hours duration. After completion of reaction, residual water present in mixture was removed by applying vacuum of 650 mm/Hg for 1 hour duration to the system.

Example 4.2

(103) Preparation of Polyetheramine Modified Polyamide-Phenalkamine by Using Cardanol Based Polyamide Prepared from TEPA, Paraformaldehyde and Polyetheramine.

(104) In one liter reaction flask following ingredients was charged to prepare a polyetheramine modified polyamide-phenalkamine based curing agent:

(105) 250 g of Cardanol based polyamide prepared from TEPA

(106) 11.60 g of Paraformaldehyde

(107) 125 g of polyetheramine Jeffamine D 230

(108) 0.2 g of oxalic acid (catalyst)

(109) The above same procedure was used for the synthesis of polyetheramine modified polyamide-phenalkamine prepared from cardanol based polyamide prepared from TEPA, paraformaldehyde and polyetheramine.

Example 4.3

(110) Preparation of Polyetheramine Modified Polyamide-Phenalkamine by Using Cardanol Based Polyamide Prepared from AEP, Paraformaldehyde and Polyetheramine.

(111) In one liter reaction flask following ingredients was charged to prepare a polyetheramine modified polyamide-phenalkamine based curing agent:

(112) 250 g of Cardanol based polyamide prepared from AEP

(113) 11.60 g of Paraformaldehyde

(114) 125 g of polyetheramine Jeffamine D 230

(115) 0.2 g of oxalic acid (catalyst)

(116) The above same procedure was used for the synthesis of polyetheramine modified polyamide-phenalkamine prepared from cardanol based polyamide prepared from AEP, paraformaldehyde and polyetheramine.

Example 5

(117) Preparation of Cured Material by Using Cardanol based Polyamide/Polyamide-Phenalkamine/Polyetheramine Modified Polyamide-Phenalkamine with Epoxy Resin

(118) The epoxy resin Diglycidyl Ether of Bisphenol A was mixed with each of all above Examples 2.1, 2.2, 2.3, 3.1, 3.2, 3.3, 4.1, 4.2 and 4.3, respectively. The mixtures were degases at 650 mm/Hg for 15 minutes and afterwards poured in suitable container at room temperature for 3 hours to form a thermoset.

(119) All the thermosets, i.e., cured materials, obtained in Example 5 passed 10 thermal cycle test at (−40/100° C.) for 1 hour.

(120) Comparison of physical properties of above newly developed system with standard polyamide based curing agent.

(121) TABLE-US-00001 Final performance Viscosity at 25° C. Amine Value in property in cP mg KOH/g Hardness (Shore D) Standard 10000 380 80-85 Polyamide Ex. 2.1 6500 370 80-85 Ex. 2.2 12000 374 80-85 Ex. 2.3 6700 390 80-85 Ex. 3.1 10000 380 80-85 Ex 3.2 17000 390 80-85 Ex. 3.3 11000 370 80-85 Ex 4.1 1300 385 80-85 Ex. 4.2 1800 370 80-85 Ex. 4.3 11500 387 80-85

(122) Methods

(123) The properties summarized in Table 2 above were measured applying the following methods.

(124) The viscosity was measured at a temperature of 25° C. [in cP] using the BROOKFIELD viscometer, spindle number 27 at share rate of 10 rpm.

(125) The Amine Value in mg KOH/g was measured using the below method: Reagents:—Glacial acetic acid Perchloric acid in glacial acetic acid 0.1 N standardised. Crystal violet indicator solution. (dissolve 1.0 g crystal violet in 100 ml glacial acetic acid.) Apparatus:Idometric flack—capacity 250 ml Graduated glass cylinder capacity 50 ml Burette—capacity 25 ml (min dev.0.1 ml) Precision balance. Procedure: 1. Weigh accurately 0.3-0.5 g sample in a clean & dry idometric flask. 2. Dissolve in about 50 ml glacial acetic acid worm if necessary, cool to room temp. 3. Titrate against standardised perchloric acid using crystal violet indicator solution till colour change from violet to green. 4. Note the reading (R ml)

(126) Calculation:

(127) $\mathrm{Amine}\mathrm{value}=\frac{56.1\times N\times R}{\mathrm{Weight}\mathrm{of}\mathrm{sample}}$

(128) N=Normality of perchloric acid

(129) R=ml of perchloric acid required.

(130) The Gel Time was measured at a temperature of in Minutes (Mixing ratio of resin and hardener: 65:35) using gelation timer (TECHNE instrument).

(131) The Glass Transition Temperature (Tg/° C.) was measured using the Metter Toledo at a rate of 10° C./min in air (25° C. to 600° C.).

(132) The Hardness (Shore D) was measured using the DUROMETER FROM HIROMETER at 25° C.

(133) The thermal shock cycles were performed using the CM Envirosystem, model Kinetic 25 B2 at −40/100° C. No. of Thermal Cycle Passed at −40/100° C. for 1 hour duration each.