N-substituted arylamino-phenol-formaldehyde condensates

Abstract

There is disclosed N-substituted arylamino-phenol-formaldehyde condensates which are substantially free of water, contain not more than 2% by weight of a phenol and possess unobvious properties, e.g., which have the residues of an N-substituted arylamine and 1.5 to 3 moles of formaldehyde for each mole of the said arylamine, contain from about 35% to 63% by weight of phenol residue, contain at least 3.5% by weight of nitrogen, have a melt viscosity of less than 2,000 cps at 175° C., a hydroxyl equivalent of about 195 to 220, a Methanol Tolerance of at least 40%, high solubility in organic solvents commonly used in epoxy formulations, and are self-catalyzing curatives for epoxy resins. The condensate of this invention are prepared by: (A) charging to a reaction vessel a phenol and (a) one member selected from the group consisting of formaldehyde and N-substituted arylamine to form a reaction mixture, (b) charging the remaining member of said group to the reaction mixture; (B) heating the reaction mixture until all of the formaldehyde and said arylamine have reacted and the condensate contains form about 35% to about 63% by weight of phenol resude. Additionally disclosed are epozy compositions containing the condensates of this invention as well as laminates prepared with the epoxy compositions.

1 . A method for the preparation of an N-substituted arylamine-phenol-formaldehyde condensate which comprises: 
 (A) charging to a reaction vessel a phenol and    (a) one member selected from the group consisting of formaldehyde and N-substituted arylamine to form a reaction mixture,    (b) charging the remaining member of said group to the reaction mixture;    (B) heating the reaction mixture until all of the formaldehyde and said arylamine have reacted and the condensate contains from about 35% to about 63% by weight of phenol residue after removal of water and free phenol from the reaction product and wherein    (i) 1.5 to 4 moles of a phenol and 1.5 to 3 moles of formaldehyde are charged to the reaction mixture for each mole of the N-substituted arylamine    (ii) the phenol is a member selected from the group consisting of phenol itself, an alkylphenol having from 1 to 4 carbon atoms in the alkyl group, a meta- or ortho-alkoxyphenol having from 1 to 4 carbon atoms in the alkoxy group, and mixtures thereof; and said N-substituted arylamine is a member selected from the group consisting of a compound of the following Formula I, Formula II, as well as mixtures thereof wherein one or more of the Formula I compounds makes up at least 80% by weight of the N-substituted arylamine:                          wherein R is lower alkyl containing 1-4 carbon atoms, hydroxyethyl, or hydroxy propyl; R′ is a member selected from the group consisting of hydrogen, methyl or ethyl in the ortho or meta position in relation to the nitrogen; and X is a member selected from the group consisting of a covalent bond, oxygen, sulfur, carbonyl, and SO2.    
     
     
         2 . The method of  claim 1  wherein the heating in step (B) is within the range of about 70° C. to about 110° and substantially all of the N-substituted arylamine is of Formula I.  
     
     
         3 . The method of  claim 1  wherein up to 20 mole % of the formaldehyde is substituted with another aldehyde having from 2 to 7 carbon atoms.  
     
     
         4 . The method of  claim 1  wherein the N-substituted arylamine is N-methylaniline, N-ethylaniline, or a mixture thereof.  
     
     
         5 . The method of  claim 1  wherein: the N-substituted arylamine is N-methylaniline, N-ethylaniline, or a mixture thereof; the phenol is phenol itself, or a mixture of phenol itself and a meta- or ortho-substituted alkylphenol having from 1 to 4 carbon atoms in the alkyl group wherein the phenol itself makes up at least 90% by weight of the mixture.  
     
     
         6 . The method of  claim 5  wherein the phenol is phenol itself.  
     
     
         7 . The method of  claim 1  wherein the reaction mixture of phenol, N-substituted arylamine and formaldehyde is at a pH above 6.5  
     
     
         8 . The method of  claim 1  wherein a tertiary aliphatic amine having a pK basicity of about 9.5 to about 11.3 is added to the reaction mixture after the N-substituted arylamine has reacted and the quantity of such addition is from about 0.5 to 2% based on the weight of phenol charged.  
     
     
         9 . The method of  claim 1  wherein about 0.5% to about 3% of an acid having a pK acidity of about 1 to 5 is added to the reaction mixture, the percent acid being based on phenol weight.  
     
     
         10 . The method of  claim 9  wherein the acid is a member selected from the group consisting of oxalic acid, formic acid, acetic acid and mixtures thereof.  
     
     
         11 . The N-substituted arylamine-phenol-formaldehyde condensate prepared by the method of  claim 1 .  
     
     
         12 . A method for the preparation of an N-substituted arylamine-phenol-formaldehyde condensate which comprises: (A) charging to a reaction vessel, an N-substituted arylamine, about 1.5 to 4 moles of a phenol for each mole of said arylamine, and thereafter adding about 1.5 to 3 moles of formaldehyde for each mole of said arylamine to form a reaction mixture; (B) heating the reaction mixture at a temperature of about 40° C. to 70° C. until the reaction mixture is substantially free of N-substituted arylamine; and (C) after the reaction mixture is substantially free of N-substituted arylamine, heating the reaction mixture at a temperature of at least 70° C. and substantially completing reaction of phenol in the reaction mixture wherein the phenol is a member selected from the group consisting of phenol itself, an alkylphenol having from 1 to 4 carbon atoms in the alkyl group, a meta- or ortho-alkoxyphenol having from 1 to 4 carbon atoms in the alkoxy group, and mixtures thereof; and said N-substituted arylamine is a member selected from the group consisting of a compound of the following Formula I and Formula II as well as mixtures thereof wherein one or more of the Formula I compounds makes up at least 10% by weight of the N-substituted arylamine:  
       
         
           
           
               
               
           
         
       
       wherein R is lower alkyl containing 1-4 carbon atoms, hydroxyethyl, and hydroxy-propyl; R′ is a member selected from the group consisting of hydrogen, methyl or ethyl in the ortho or meta position in relation to the nitrogen; and X is a member selected from the group consisting of a covalent bond, oxygen, sulfur, carbonyl, and SO2.  
     
     
         13 . The method of  claim 12  wherein the N-substituted arylamine is selected from the group consisting of N-methylaniline, N-ethylaniline and mixtures thereof.  
     
     
         14 . The method of  claim 13  wherein the phenol is a member selected from the group consisting of phenol itself and mixtures of phenol itself and an ortho- or meta-alkylphenol having from 1 to 4 carbon atoms in the alkyl group wherein the mixture contains at least 90%, by weight, of phenol itself.  
     
     
         15 . The method of  claim 12  wherein up to 10 mole % of the formaldehyde is substituted with another aldehyde having from 2 to 7 carbon atoms.  
     
     
         16 . The method of  claim 12  wherein the pH of the reaction mixture of phenol, said arylamine and formaldehyde is above 6.5.  
     
     
         17 . The N-substituted arylamine-phenol-formaldehyde condensate prepared by the method of  claim 12 .  
     
     
         18 . The N-substituted arylamine-phenol-formaldehyde condensate prepared by the method of  claim 12  wherein the phenol is phenol itself.  
     
     
         19 . A method for the preparation of an N-substituted arylamine-phenol-formaldehyde condensate which comprises: (A) charging to a reaction vessel, about 1.5 to 4 moles of a phenol for each mole of N-substituted arylamine to be added, about 1.5 to 3 moles of formaldehyde for each mole of N-substituted arylamine to be added and thereafter adding the N-substituted arylamine to form a reaction mixture; (B) heating the reaction mixture at a temperature of about 50° C. to about 80° C. until the reaction mixture is substantially free of N-substituted arylamine; and (C) after the reaction mixture is substantially free of N-substituted arylamine, heating the reaction mixture at a temperature of at least 70° C. and substantially completing reaction of phenol in the reaction mixture; wherein the phenol is a member selected from the group consisting of phenol itself, an alkylphenol having from 1 to 4 carbon atoms in the alkyl group, a meta- or ortho-alkoxyphenol having from 1 to 4 carbon atoms in the alkoxy group, and mixtures thereof; and the N-substituted arylamine is a member selected from the group consisting of a compound of the following Formula I, a Formula II compound, as well as mixtures thereof wherein one or more of the Formula I compounds makes up at least 90% by weight of the N-substituted arylamine:  
       
         
           
           
               
               
           
         
       
       wherein R is lower alkyl containing 1-4 carbon atoms, hydroxyethyl, hydroxy propyl; R′ is a member selected from the group consisting of hydrogen, methyl or ethyl in the ortho or meta position in relation to the nitrogen; and X is a member selected from the group consisting of a covalent bond, oxygen, sulfur, carbonyl, and SO2.  
     
     
         20 . The method of  claim 19  wherein the N-substituted arylamine is selected from the group consisting of N-methylaniline, N-ethylaniline, and mixtures thereof.  
     
     
         21 . The method of  claim 19  wherein up to 10 mole % of the formaldehyde is substituted with another aldehyde having from 2 to 7 carbon atoms.  
     
     
         22 . The method of  claim 19  wherein the N-substituted arylamine is N-methylaniline, N-ethylaniline, or a mixture thereof and the phenol is phenol itself, or a mixture of phenol itself and a meta- or ortho-substituted alkylphenol having from 1 to 4 caarbon atoms in the alkyl group wherein the phenol itself makes up at least 90% by weight of the mixture.  
     
     
         23 . The method of  claim 22  wherein the phenol is phenol itself.  
     
     
         24 . The method of  claim 19  wherein the pH of reaction mixture of the phenol, N-substituted arylamine and formaldehyde is at a pH above 6.5  
     
     
         25 . The method of  claim 19  wherein a tertiary aliphatic amine having a pK basicity of about 9.5 to about 11.3 is added to the reaction mixture after the N-substituted arylamine has reacted and the quantity of such addition is from about 0.5 to 2% based on the weight of phenol charged.  
     
     
         26 . The N-substituted arylamine-phenol-formaldehyde condensate prepared by the method of  claim 19 .  
     
     
         27 . A condensation product of an N-substituted arylamine, a phenol, and formaldehyde, said condensation product being substantially free of water and having from about 3.5% to 6.5% nitrogen by weight, not more than 2% by weight of free phenol and a hydroxyl equivalent of about 195 to 220, wherein the phenol is a member selected from the group consisting of phenol itself, an alkylphenol having from 1 to 4 carbon atoms in the alkyl group, a meta- or ortho-alkoxyphenol having from 1 to 4 carbon atoms in the alkoxy group, and mixtures thereof; and said N-substituted arylamine is a member selected from the group consisting of a compound of the following Formula I, Formula II as well as mixtures thereof wherein one or more of the Formula I compounds makes up at least 80% by weight of the N-substituted arylamine:  
       
         
           
           
               
               
           
         
       
       wherein R is lower alkyl containing 1-4 carbon atoms, hydroxyethyl, or hydroxy- propyl; R′ is a member selected from the group consisting of hydrogen, methyl or ethyl in the ortho or meta position in relation to the nitrogen; and X is a member selected from the group consisting of a covalent bond, oxygen, sulfur, carbonyl, and SO2.  
     
     
         28 . The product of  claim 27  which contains from about 4. 5% to about 6% of nitrogen and has a melt viscosity of not more than about 2,000 cps at 175° C. and one or more of the Formula I compounds makes up at least 90% by weight of the N-substituted arylamine.  
     
     
         29 . The product of  claim 27  wherein the condensate contains from about 35% to 63% by weight of phenol residue and has a melt viscosity of not more than about 1,000 cps at 175° C.  
     
     
         30 . The product of  claim 27  wherein the phenol is phenol itself or a mixture of phenol itself and not more than 10% by weight of an ortho- or meta-alkylphenol having from 1 to 4 carbon atoms in the alkyl group.  
     
     
         31 . The product of  claim 27  wherein the N-substituted arylamine is a member selected from the group consisting of N-methylaniline, N-ethylaniline and mixtures thereof.  
     
     
         32 . The product of  claim 27  wherein up to 10 mole percent of the formaldehyde is replaced with another aldehyde having from 2 to 7 carbon atoms.  
     
     
         33 . The product of  claim 27  wherein such product has a Methanol Tolerance of at least 40% at 25° C. by the Methanol Tolerance Method.  
     
     
         34 . An epoxy resin composition comprising: (A) an epoxy resin; and (B) the condensation product of  claim 27  wherein for each 100 parts by weight of epoxy resin the composition contains: (a) about 0-30 parts of phenolic-formaldehyde novolac; and (b) about 5 to 100 parts of said condensate; (c) provided that when the quantity, by weight, of of said condensate is 5-25 parts, the quantity of said novolac is about 20-30 parts by weight.  
     
     
         35 . The composition of  claim 34  wherein the phenol is phenol itself and the N-substituted arylamine is a member selected from the group consisting of N-methyl or N-ethyl aniline.  
     
     
         36 . A prepreg comprising a porous substrate impregnated with the epoxy resin composition of  claim 34 .  
     
     
         37 . A prepreg of  claim 36  wherein the condensation product dissolves completely when a mixture of equal parts by weight of said condensation product and n-butanol is heated at 60° C. and remains dissolved upon cooling to room temperature.  
     
     
         38 . A laminate comprising a plurality of prepregs according to  claim 36  laminated together wherein said epoxy resin composition is cured.  
     
     
         39 . A condensation product containing: (A) the residue of one mole of a member selected from the group consisting of N-methylaniline, N-ethylaniline and mixtures thereof for each 1.5 to 3 moles of formaldehyde residue; from about 40% to 60% by weight of a member selected from the group consisting of the residue of phenol itself, a mixture of phenol itself and an alkylphenol having from 1 to 4 carbon atoms is the alkyl group; and from about 3.5% to 6.5% nitrogen by weight; (B) ) a Methanol Tolerance of at least 40% at 25° C. as measured by the Methanol Tolerance Method; and (C) wherein said product is substantially free of water and contains not more than about 2% by weight of free phenol.  
     
     
         40 . A product of  claim 39  having a melt viscosity of not more than 1,000 cps at 175° C., which contains 4.5% to 6% by weight of nitrogen, and the phenol is phenol itself and the said aniline is N-ethylaniline.