U.S. patent application number 10/869271 was filed with the patent office on 2005-01-06 for n-substituted arylamino-phenol-formaldehyde condensates.
Invention is credited to Gerber, Arthur H..
Application Number | 20050003202 10/869271 |
Document ID | / |
Family ID | 31990501 |
Filed Date | 2005-01-06 |
United States Patent
Application |
20050003202 |
Kind Code |
A1 |
Gerber, Arthur H. |
January 6, 2005 |
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.degree. 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.
Inventors: |
Gerber, Arthur H.;
(Louisville, KY) |
Correspondence
Address: |
CANTOR COLBURN, LLP
55 GRIFFIN ROAD SOUTH
BLOOMFIELD
CT
06002
|
Family ID: |
31990501 |
Appl. No.: |
10/869271 |
Filed: |
June 16, 2004 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
10869271 |
Jun 16, 2004 |
|
|
|
10235326 |
Sep 5, 2002 |
|
|
|
6780511 |
|
|
|
|
Current U.S.
Class: |
428/413 ;
428/396; 525/523; 528/129 |
Current CPC
Class: |
C08L 63/00 20130101;
C08L 61/14 20130101; Y10T 428/31515 20150401; Y10T 428/31511
20150401; C08G 8/28 20130101; C08L 63/00 20130101; H05K 1/0326
20130101; Y10T 428/2971 20150115; Y10T 428/249941 20150401; Y10T
428/2933 20150115; C08L 2666/16 20130101 |
Class at
Publication: |
428/413 ;
428/396; 525/523; 528/129 |
International
Class: |
B32B 027/38; C08L
063/00; C08G 014/02 |
Claims
What is claimed is:
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: 4wherein 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.degree. C. to about 110.degree. 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.degree. C. to
70.degree. 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.degree. 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: 5wherein 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.degree. C. to about 80.degree. 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.degree. 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: 6wherein 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: 7wherein 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.degree. 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.degree. 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.degree. 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.degree. 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.degree. 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.degree. C., which contains 4.5% to 6% by weight of
nitrogen, and the phenol is phenol itself and the said aniline is
N-ethylaniline.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a divisional application of U.S. Ser.
No. 10/235,326, filed Sep. 5, 2002, which is incorporated herein by
reference in its entirety.
BACKGROUND AND SUMMARY
[0002] This invention relates to nitrogen containing N-substituted
arylamino-phenol-formaldehyde condensates, e.g. those of
N-ethylaniline-phenol-formaldehyde, which have a low melt
viscosity, are soluble in solvents commonly used in epoxy
formulations, and are self-catalyzing curatives for epoxy resins.
This latter property permits faster curing and/or curing at lower
temperatures while providing adequate mix life.
[0003] It has now been found that N-substituted
arylamino-phenol-formaldeh- yde condensates having desirable and
unexpected properties can be produced by:
[0004] (A) charging to a reaction vessel a phenol and (a) one
member selected from the group consisting of formaldehyde and an
N-substituted arylamine, e.g. N-ethylaniline, to form a reaction
mixture; subsequently (b) charging the remaining member of said
group to the reaction mixture;
[0005] (B) heating the reaction mixture until all of the
formaldehyde and said arylamine have reacted and the condensate
contains from about 35% to 63% by weight of phenol residue
wherein
[0006] (i) the molar ratio of said phenol to formaldehyde to said
arylamine is 1.5 to 4 moles of the phenol and 1.5-3 moles of
formaldehyde for each mole of the arylamine;
[0007] (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
[0008] (iii) said arylamine is a member selected from the group
consisting of a mononuclear (1) or dinuclear (11) compound as
represented by the following Formula I and Formula II,
respectively: 1
[0009] wherein R is alkyl of 1 to 4 carbon atoms, hydroxyethyl or
hydroxypropyl; R' is hydrogen, methyl or ethyl in the ortho or meta
position in relation to the nitrogen; and X is either a covalent
bond, oxygen, sulfur, carbonyl or --SO2--. In place of the
formaldehyde being substantially all formaldehyde, the above method
includes the substitution of up to about 20 mole percent of the
formaldehyde with an equal molar quantity of another aldehyde
having from 2 to 7 carbon atoms.
[0010] The condensates of this invention have a nitrogen content of
about 3.5% to about 6.5% by weight. Thus, in addition to being
effective self-catalyzing curing agents for epoxy resins, the
condensates of this invention also provide enhanced fire-retardant
properties to epoxy compositions. Furthermore, lower concentrations
of the condensates can be employed as accelerators for curing epoxy
resins with phenol-formaldehyde resins as compared to the use of
conventional accelerators. Condensates of this invention also
provide other beneficial properties that include, but are not
limited to, improved adhesion to metals, particularly copper,
improved impact resistance to cured epoxy formulations, and
improved moisture resistance as compared to phenol-formaldehyde
novolac curing agents. The condensates of this invention are also
suitable in the manufacture of molded products as well for other
uses enjoyed by phenolic novolac resins.
BACKGROUND AND PRIOR ART
[0011] The reaction of phenolic compounds with amines, generally
secondary amines, and formaldehyde is well known and are an example
of the Mannich condensation, e.g., see H. A. Bruson, C. W.
McMullen, J. Am. Chem. Soc., 63, 270 (1941); M. Julia, Bull. Soc.,
Chim. France, 1955, 830; and R. L. Hull, J. Am. Chem. Soc., 77,
6376 (1955). However, the products of the reactions cited in the
above references are oligomers as contrasted to polymers having
more than 4 repeating units and may act as accelerators for epoxy
reactions but not as effective curing agents. The reason for this
is that the hydroxyl functionality of such materials is only about
one or two which provides insufficient crosslinking as compared to
conventional curing agents such as phenol-formaldehyde curing
agents which have a hydroxyl functionality of at least 6. Likewise
the products of substituted phenols with N-monoalkylanilines and
formaldehyde(M. Miocque, J. M. Vierfond, Bull. Soc. Chem. France,
1970, 1901, or with N,N-dialkylanilines and formaldehyde (ibid, p.
1896) give monoaminomethylated products unsuitable as effective
epoxy curing agents whereas the condensates of this invention
produce polymers having more repeating units and viscosities of at
least 700 cps at 150.degree. C.
[0012] U.S. Pat. No. 4,518,748 of May 21, 1985 to Haug et al. as
well as U.S. Pat. No. 4,552,935 of Nov. 12, 1985 to Haug et al.,
show curable epoxide compositions containing condensates prepared
from certain phenols, certain amines and aldehydes in an acid
medium. However, only primary and tertiary amines are shown.
[0013] U.S. Pat. No. 5,569,536 of Oct. 19, 1996 to J. Hunter et al.
use polyamines with primary amino end groups and further, the mole
ratio of ingredients are substantially different from those of the
instant invention. Furthermore, the condensates of this 536 patent
cannot form significant amounts of acyclic tertiary amino
linkages.
[0014] N,N'-dialkylalkylene diamines can form condensates with
phenol and an aldehyde. However, the alkylene group unlike the
arylene group is more susceptible to thermal and flame degradation.
Moreover, such condensates would be more highly basic than the
condensates of the instant invention and would provide poor mix
stability in formulations with epoxy resins. Basic ionization
constants (pK) for highly basic amines such as
N,N-dimethylbenzylamine, and N,N-dimethyl hexylamine are 9.02, and
ca. 10, respectively.
[0015] Primary aliphatic or aromatic amines, unlike the
N-substituted arylene amines of the instant invention, react with
aldehydes to form unstable N,N-dimethylol compounds or
alkyleneimines which generally are unstable and can trimerize or
even polymerize (J. F. Walker, "Formaldehyde", 3 rd ed. pp.
360-362, 370, 1964, Reinhold Publishing Corp.). Tertiary amino
N,N-dialkylarylamines cannot form the tertiary amino N--CH2--groups
as part of a condensate. Tertiary amino groups of the instant
condensates, particularly as the idealized repeating units of
(N--CH2-Aryl-CH2-Aryl-)n, are believed to be responsible for
enhancing the flexibility/toughness of cured epoxy resins.
[0016] In Chem. Abst., 45, 2487i (1951), W. J. Burke et al.,
several primary amines were reacted with formaldehyde and
polyhydroxy benzenes (i.e., hydroxyphenols) to give substituted
benzo bis-and tris-m-oxazines.
[0017] In Chem. Abst., 47, 5408i (1953), W. J. Burke et al.,
2-Naphthol was condensed with formaldehyde and aliphatic or
alicyclic primary amines to give substituted naphtho m-oxazines or
substituted methylene diamines, depending on reaction conditions.
None of the above Burke et al. products were polymeric and none
were derived from aromatic amines.
[0018] In Chem. Abst., 50, 6408i (1956) W. J. Burke et al.,
aromatic primary amine, 2-naphthylamine, was reacted with
formaldehyde and 2-naphthol. Products of this reaction were
non-polymeric being a substituted naphthol m-oxazine and a
naphthylaminomethylated 2-naphthol. None of the above W. J. Burke
et al. references use an N-substituted amine.
[0019] Primary aromatic amines can also be reacted with phenol and
aldehydes such as formaldehyde to give benzoxazines. In the case of
a diphenolic compound a primary amine and formaldehyde difunctional
benzoxazines and other oligomers are formed (A. Gardziella, L. A.
Pilato, A. Knop, "Phenolic Resins", pp. 57-58, 1999,
Springer-Verlag, N.Y.). Benzoxazines, unlike the condensates of the
instant invention undergo facile ring opening with active hydrogen
compounds including phenol and phenolic oligomers.
SUMMARY OF THE INVENTION
[0020] In one aspect, this invention is directed to 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.degree. 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.
[0021] In another aspect, this invention is directed to an epoxy
resin composition containing an N-substituted
arylamino-phenol-formaldehyde condensate of this invention.
[0022] In another aspect, this invention is directed to prepregs
containing compositions of an epoxy resin and an N-substituted
arylamino-phenol-formaldehyde condensate of this invention.
[0023] In another aspect, this invention is directed to cured
compositions comprising the N-substituted
arylamino-phenol-formaldehyde condensates of this invention with
epoxy resins as well as laminates containing the condensates and
epoxy resins.
[0024] In yet another aspect of this invention the N-substituted
arylamine-phenol-formaldehyde condensates of this invention either
alone or in admixture with another epoxy curing agent and/or
another fire-retardant can be used as fire-retardant curing agents
for epoxy resins.
[0025] In another aspect, this invention is directed to methods for
the manufacture of the N-substituted arylamino-phenol-formaldehyde
condensates as well as epoxy compositions, prepregs and laminates
containing the same.
[0026] In another aspect, this invention is directed to the
condensates, epoxy compositions, prepregs and laminates prepared by
the above described methods.
DETAILED DESCRIPTION OF THE INVENTION
[0027] The Phenol Monomer
[0028] The phenol monomer, also, simply referred to as a phenol or
simply phenol, can be: phenol itself; an alkyl phenol having from 1
to 4 carbon atoms in the alkyl grup, preferably a meta or ortho
alkyl phenol having from 1 to 4 carbon atoms in the alkyl group,
and mixtures thereof. Illustrative of a phenol there can be
mentioned: phenol itself; meta-cresol; ortho-cresol; para-cresol;
4-ethyl phenol; 4-methyl phenol; 2-ethyl phenol; 3-ethyl phenol;
3-isopropyl phenol; 3-methoxy phenol; 3-ethoxy phenol; 3-isobutyl
phenol; etc. Phenol itself is the preferred phenol monomer. The
quantity of a phenol charged to the reactor in the manufacture of
the condensates of this invention is from about 1.5 to 4 moles of a
phenol for each mole of N-substituted arylamine. Preferably, 2 to 4
moles of a phenol are charged for each mole of the N-substituted
arylamine. Also preferred is a mixture of at least 90% by weight of
phenol itself and not more than 10% by weight of the alkyl phenol,
alkoxy phenol and mixtures of the alkyl phenol and alkoxy phenol,
particularly when the phenol is an ortho- or meta-substitured alkyl
phenol. The quantity of phenol charged to the reactor is much
greater than the amount which reacts in the formation of the
condensates so that free, unreacted, phenol is typically distilled
out of the reaction mixture after completion of the reaction.
[0029] The N-Substituted Arylamine Monomer
[0030] The N-substituted arylamine monomer can be either mono
nuclear or di-nuclear as represented by Formula I and Formula II
below as well as mixtures thereof wherein one or more Formula I
compounds make up at least 80% and preferably at least 90% by
weight of the N-substituted arylamine: 2
[0031] wherein each R is alkyl containing 1-4 carbon atoms,
hydroxyethyl, and hydroxypropyl; R' is hydrogen, methyl or ethyl in
ortho or meta position to the nitrogen; and X is selected from a
covalent bond, O, S, carbonyl, and --SO 2--. As representative
examples of Formula I compounds, there can be mentioned
N-methylaniline, N-ethylaniline, N-ethyl-2-methylaniline,
N-methyl-2-methylaniline, N-methyl-3-ethylaniline, and
N-hydroxyethylaniline. As representative examples of Formula II
compounds, there can be mentioned N,N'-dimethylbenzidine, bis
(4-N-ethylphenylamino) sulfide; bis (4-N-methylphenylamino) oxide;
bis (4-N-methylphenylamino) sulfone; and bis (4,4'-N-ethylamino)
benzophenone. Compounds of Formula I are preferred and
N-ethylaniline and N-methylaniline are particularly preferred.
[0032] The quantity of the N-substituted arylamine charged to the
reactor is about one mole for the total of 1.5 to 4 moles of the
phenol and 1.5 to 3 moles of the formaldehyde.
[0033] The Formaldehyde Monomer
[0034] The formaldehyde monomer is preferably formaldehyde.
However, up to about 20 mole % and preferably up to about 10 mole %
of the formaldehyde can be replaced with other aldehydes such as
those having from 2 to 7 carbon atoms. Illustrative of other
aldehydes there can be mentioned: acetaldehyde, i-butyraldehyde,
benzaldehyde; and mixtures thereof. The assay of 50% formalin used
in the examples herein varied from 50.0% to 50. 3%. Weights charged
were such to provide the indicated moles. The term "formaldehyde"
or "aldehyde" herein includes not only formaldehyde itself or other
designated aldehydes, but also compounds yielding an aldehyde, e.
g., paraformaldehyde, trioxymethylene, paraformaldehyde and the
like. The aldehyde may be introduced neat or as a 20% to 50%
solution in phenol to facilitate metering in the reaction mixture.
However, the formaldehyde is generally charged to the reaction
mixture as 50% formalin. Formalin generally contains small
quantities of formic acid with about 0.03% of formic acid being
typical in a 50% formalin solution.
[0035] The quantity of formaldehyde used in manufacture of the
condensates of this invention varies from about 1.5 to 3 moles for
each mole of the N-substituted arylamine, preferably, 1.8 to 2.2
moles per mole of N-substituted arylamine.
[0036] The Acid
[0037] Acids, preferably organic acids, when used in the methods of
manufacture of the condensates of this invention have pK acidities
of about one to about five. They are used at about 0.5% to about 3%
based on phenol weight. Examples of such acids include oxalic acid,
phenyl phosphonic acid, phosphoric acid, acetic acid, formic acid
and lactic acid. The use of added acid in the methods of this
invention produce condensates having higher viscosities and higher
molecular weights as compared to the same method without the use of
added acid. The condensates with the lower viscosities and lower
molecular weights are preferred over those with higher viscosities
and higher molecular weights.
[0038] Control of pH with Tertiary Amine
[0039] Strong organic tertiary aliphatic amines can be optionally
employed in the manufacturing Methods (2) and (3) described
hereafter. The tertiary amine is preferably added after the
N-substituted arylamine has substantially reacted. The intent of
adding the amine is to facilitate reaction of phenol with the
aldehyde. pK basicities for the amines used for such pH control are
about 9.5 to about 11.3, preferably at least 10. They are used at
about 0.5% to about 2% by weight of phenol. Examples of such amines
are represented by triethylamine, tributylamine,
diethylisopropylamine, N-methyl- and N-ethyl piperidine,
N,N-dimethylcyclohexylamine, and di-n-butylaminoethanol.
[0040] The Solvent
[0041] Solvents for the condensates can be optionally employed in
all methods for the manufacture of the condensates of this
invention and can be added before or after addition of formaldehyde
[Methods (1) and (2) described hereafter] or N-substituted
arylamine [Methods (3) and (4) described hereafter]. Solvent
classes include aliphatic alcohols, mono-alkyl ethers of alkylene
glycols and di-alkyl ethers of alkylene glycols. These solvents can
advantageously be employed to replace a significant portion of
excess phenol. The solvent and excess unreacted phenol can
subsequently be recovered by atmospheric or vacuum distillation at
elevated temperatures. Representative solvents include n-butanol,
isobutanol, alkoxy (1 to 4 carbon atoms) ethanols, mono-alkoxy (1
to 4 carbons atoms) ethers of diethylene glycol, di-methyl and
di-ethyl ethers of diethylene glycol. High boiling point (i.e., at
least about 160.degree. C.) solvents (e.g., monomethylether ether
of diethylene glycol) can be recovered simultaneously with phenol
and re-used in a subsequent reaction. The preferred solvents are
those which have a boiling point close to that of phenol.
[0042] The N-Substituted Arylamino-Phenol-Formaldehyde
Condensates
[0043] The condensates of this invention will contain from about
3.5% to 6.5% nitrogen, preferably about 5% to 6% nitrogen based on
the weight of the condensate; have a melt viscosity of from about
700 cps (centipoise) at 150.degree. C. to not more than about 2,000
cps at 175.degree. C. and preferably not more than 1,000 cps at
175.degree. C.; be substantially free of water; and contain not
more than about 2% by weight of free (unreacted) phenol. Preferred
condensates will have a Methanol Tolerance of at least about 40% as
measured by the Methanol Tolerance method at 25.degree. C., e.g.
about 40% to 800%.
[0044] The quantity of phenol residue in the condensates of this
invention is from about 35% to 63%, preferably 40% to 60% and
particularly about 43% to 55% by weight of the condensate. The term
"residue" or "residues" of a reactant, e.g., phenol, refers to the
quantity of reactant consumed in the preparation of the condensates
of this invention. Illustratively, if 10 grams (g) of a phenol is
consumed in the reaction with an N-substituted arylamine and
formaldehyde, the phenol residue of the composition would be 10
grams. Also, if 20 grams of a phenol is glycidylated and the
glycidylated product is subsequently reacted with a
phenol-formaldehyde novolac, the glyoxal-phenolic residue would
still be 20 grams.
[0045] The condensates of this invention have hydroxyl equivalents
of about 195 to about 220 as calculated from product yield (grams)
by determining phenol content after subtracting the contribution of
N-substituted arylamine and methylene (fragment resulting from
formaldehyde). They are soluble in a variety of organic solvents
including, but not limited to, n-butyl alcohol, methyl ethyl ketone
(MEK), methyl isobutyl ketone, 2-ethoxyethanol,
1-methoxy-2-propanol, monomethylether of diethylene glycol, (methyl
carbitol), bis(2-methoxyethyl)ether (diglyme), and
N,N-dimethylacetamide. A variety of solvents and solvent mixtures
are thus available to the laminating industry.
[0046] Condensates of the instant invention shows superior
fire-retardance compared to phenol-formaldehyde novolacs as epoxy
curing agents. Further enhancement of fire-retardency will occur
when used in conjunction with high nitrogen (16%-20%)
triazine-phenol-formaldehyde condensates and also when using
phosphorus containing material, e.g. triphenlphosphine (at a
concentration of about 1% in the epoxy resin) as accelerator,
particularly with another phosphorus containing material, e. g.,
phosphorus acid.
[0047] Procedures for the Manufacture of the Condensates of this
Invention.
[0048] Broadly the condensates of this invention are made by (A)
charging to a reaction vessel a phenol and
[0049] (a) one member selected from the group consisting of
formaldehyde and N-substituted arylamine to form a reaction
mixture, preferably the reaction mixture is at a temperature of not
less than about 40.degree. C., and particularly about 50.degree. C.
to 80.degree. C.,
[0050] (b) charging the remaining member of said group to the
reaction mixture;
[0051] (B) heating the reaction mixture, until all of the
formaldehyde and said arylamine have reacted, preferably at a
temperature of about 70.degree. C. to 110.degree. C., and the
condensate contains from about 35% to about 63% by weight of phenol
residue and wherein
[0052] (I) 1.5 to 4 moles of a phenol and 1.5 to 3 moles of
formaldehyde are charged to the reactor for each mole of the
N-substituted arylamine,
[0053] (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 and
Formula II as well as mixtures thereof wherein one or more of the
Formula I compounds make up at least 80%, and preferably 90%, by
weight of the N-substituted arylamine: 3
[0054] wherein R is alkyl containing 1-4 carbon atoms,
hydroxyethyl, or hydroxypropyl; 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, or SO 2. Mixtures of the various N-substituted arylamine
compounds can also be used. The formaldehyde and the said arylamine
react readily but it may be necessary to continue the heating,
preferably at an elevated temperature such as up to about
110.degree. C. until the reaction of the phenol is substantially
complete.
[0055] Within the above generic method for the manufacture of the
condensates of this invention, there are a number of preferred
submethods which are set forth below. Such submethods produce
condensates of this invention which can and often do have some
different properties from condensates produced by one of the other
methods, e.g., condensates produced under pH conditions of at least
6.5 and particularly 7.0 or more have some properties which differ
from condensates prepared under conditions of a pH of about 6 or
less.
[0056] The pH of the reaction mixture for the phenol, N-substituted
arylamine and formaldehyde or formaldehyde with another aldehyde is
generally above 6, preferably above 6.5 and particularly above 7
such as 7.5 or more.
[0057] 1. The Standard Method Using an Acid (Method 1)
[0058] In this method a phenol and an N-substituted arylamine,
e.g., N-ethylaniline, are charged to the reactor to form a mixture.
The mixture is heated at a temperature of about 30.degree. C. to
100.degree. C. and preferably from about 50.degree. C. to about
80.degree. C. and formaldehyde is added. Acid is added to the
reaction mixture, preferably an organic acid. The acid can be added
before or after introduction of the formaldehyde. Although the
reaction of the N-substituted arylamine and formaldehyde is
essentially instantaneous further heating, e.g. 70.degree. C. to
110.degree. C. is necessary to have the requisite equivalent of
phenol reacted. Typically, after addition of formaldehyde the
reaction mixture is heated several hours at 70.degree. to about
100.degree. C. until the reaction of the phenol is substantially
complete. Typical pHs of reaction mixture before and after addition
of acid are about 7.0 to 7.5 and about 5-6.5, respectively.
[0059] 2. The Standard Method Without Acid (Method 2)
[0060] This method is essentially identical to the Standard Method
described above except that no acid is used.
[0061] 3. The Reverse Method Without Acid (Method 3)
[0062] This method uses essentially the same quantities as in
Method (2) above but with two major distinctions. Phenol and
formaldehyde, not phenol and N-substituted arylamine, are charged
to the reactor. The N-substituted arylamine is then added to the
reaction mixture. The temperature at which the said arylamine is
added is preferably less than about 85.degree. C. and particularly
about 50.degree. C. to about 80.degree. C. The reactants can be
added sequentially which can serve the purpose of improving
temperature control. For example, 1/2 of the formaldehyde can be
charged with the phenol and 1/2 of the N-substitutedarylamine added
shortly thereafter. The remainder of formaldehyde is added followed
by the remainder of N-substituted arylamine. The second addition of
N-substitutedarylamine may be at the same temperature previously
used or may be higher possibly by 10.degree. C. In instances when
more than one N-substitutedarylamine is used, they can be added
together or separately. Additions of formaldehyde should be made
quickly, whereas, additions of N-substitutedarylamine should be
made gradually. Typically after addition of N-substitutedarylamine
the reaction mixture is heated several hours at about 70.degree. C.
to about 110.degree. C.
[0063] 4. The Reverse Method with Acid (Method 4)
[0064] This method is essentially identical to the Method (3) above
except that the acid is added after reaction of the
N-substitutedarylamine is substantially complete.
[0065] 5. A fifth method (Method 5)
[0066] This is similar to the Second Method cited above except that
an organic amine with pK basicity of about 9.5 to 11.3 at about
0.5% to about 2% by weight on phenol is added prior to addition of
the formaldehyde. Typical pH's of reaction mixtures are about 7.5
to about 9. Organic amines are preferred to inorganic alkaline
materials so as not to introduce metal ions which would be
deleterious in many electronic applications. The Method 5 can
continue as in the second method or, optionally, after the
N-substituted arylamine is added, an acid is added. The type of
acid and its quantity is the same as set forth hereinbefore under
the discussion on the acids to be used.
[0067] 6. A sixth method (Method 6)
[0068] This method sequentially combines Methods (2) and (3) above,
preferably with all the phenol present at the onset, for example
Method (2) is performed until the phenol is substantially reacted.
The temperature is adjusted to less than about 80.degree. C. and
Method (3) is performed. This is illustrated in Example 35
herein.
[0069] In the manufacture of the condensates of this invention,
substantially all of the aldehyde and N-substituted arylamine is
reacted whereas phenol is used in excess and is distilled out of
the reaction mixture after completion of the reaction.
[0070] Removal of Water and Free Phenol
[0071] After the substantial complete reaction of the phenol, water
can be removed from the reaction mixture by distillation.
Alternatively, the reaction can be stopped when the condensate,
i.e., after removal of free phenol and water, contains the
requisite quantity of phenol residue, e.g., from 35% to 63% by
weight of the condensate. Whatever water is not removed during any
initial distillation is removed when the excess phenol ,i.e., free
(unreacted) phenol, is removed from the reaction mixture by
conventional techniques such as that used for removal of phenol
from other novolac resins such as by raising the temperature to
about 190.degree. C. together with increasing the vacuum to about
29 inches of mercury. Steam sparging with or without vacuum at such
temperatures can also be used to remove phenol in the product,
particularly to achieve free phenol levels of not more than 2% and
particularly levels of less than 0.5% in the condensate. Steam
sparging was applied after vacuum distillation recovery of phenol
in all examples except Ex.'s 1-7, 9, 10, 13, 14, 16, 18 and 24.
[0072] The Epoxy Compositions
[0073] The epoxy resins used in making the flame retardant
compositions and laminates of this invention will typically have
WPE (weight per epoxy) values of about 190 to about 10,000 and
preferably about 190 to about 500. Illustrative of the epoxy
resins, there can be mentioned those of diglycidyl ether resins,
such as those having the above mentioned WPE values, prepared by
contacting a dihydroxy compound with an excess of epichlorohydrin
in the presence of an alkali metal hydroxide wherein the dihydroxy
compound can be: bisphenol A; brominated bisphenol A; bisphenol F;
resorcinol; neopentyl glycol; cyclohexanedimethanol, and the like ;
and mixtures thereof. Such resins are also referred to as being
based on or derived from the dihydroxy compound involved, e.g.
bisphenol A. Also, such conventional epoxy resin can be that of:
epoxy phenol novolacs; epoxy cresol novolacs, particularly glycidyl
ethers of an o-cresol/formaldehyde novolacs; aromatic glycidyl
amine resins such as triglycidyl-p-amino phenol; N,N, N',
N'-tetraglycidyl-4,4'-diaminodipheny- l methane; and glycidyl
ethers of a phenolic novolac.
[0074] Epoxy curing accelerators are used in the epoxy compositions
in a quantity sufficient to accelerate the cure of the epoxy resin.
Generally, such quantity is from about 0.05 to 0.5 parts based on
100 parts of the base epoxy resin and particularly about 0.1 to 0.2
parts. Such accelerators include 2-methylimidazole,
2-ethyl-4-methylimidazole, amines such as
2,4,6-tris(dimethylaminomethyl)phenol and benzyldimethylamine, and
organophosphorus compounds such as tributylphosphine and
triphenylphosphine.
[0075] Laminates of the Epoxy Resin Compositions
[0076] The laminate structures of this invention are conventional
laminates. Such laminates, in this case will contain a reinforcing
agent such as glass cloth, and a cured resinous matrix comprising
an epoxy resin and an N-substituted arylamino-phenol-formaldehyde
condensates of this invention as curing agent and flame-retardant
alone or together with other curing agents and/or flame retardant
agents for the epoxy resin. The laminates of this invention will
comprise the reinforcing agent together with the cured epoxy
compositions mentioned hereinabove.
[0077] The structure of the laminates of this invention are the
same as those of conventional laminates containing a reinforcing
agent such as glass cloth, and a resinous matrix comprising an
epoxy resin and a curing agent for the epoxy resin.
[0078] The laminates of this invention will generally contain about
40% to 80% by weight of resinous matrix material and about 20% to
60% by weight of reinforcing material such as glass cloth.
[0079] Conventional laminating techniques can be used in making the
laminates of this invention such as the wet or dry-lay-up
techniques. Multiple layers of resin impregnated reinforcing
material, upon curing, make up the laminate.
[0080] The pressure used in making the laminates can vary from the
contact pressure of applying a laminated lining to a tank wall to
the high pressure, e.g., 1,000 psi or more, used in the manufacture
of electrical insulation sheets. The temperature used in making the
laminates can vary over a wide range such as that of about room
temperature to over 210.degree. C. The use of a solvent in the
laminate compositions is optional. Conventional laminating
techniques can be used in making the laminates of this invention,
e.g., such as the wet or dry-lay-up techniques.
[0081] Reinforcing fibers or fabrics of reinforcing fibers for use
in laminates include glass fibers and mats, carbon and graphite
fibers, cellulosic paper, fibrous polyamide sheets, fibrous quartz
sheets, woven fibrous glass cloth, unwoven fibrous glass mat, and
the like. The epoxy resin composition will be impregnated in the
reinforcing fibers or fabrics or the interstices formed from of
such fibers or fabrics. Fillers such as quartz powdered, mica,
talc, calcium carbonate and the like may also be added to the
resinous matrix in the manufacture of the laminate.
[0082] Compositions of this invention when used in electronic
applications such as laminates for the production of printed
circuit boards will typically comprise the following composition
based on 100 parts of an epoxy resin:
[0083] (a) about 0-30 parts of phenolic-formaldehyde novolac;
[0084] (b) about 5-100 parts of the N-substituted
arylamino-phenol-formald- ehyde condensates of this invention and
preferably, when (b) is 5 to 25 parts, then (a) is about 20-30
parts.; and
[0085] (c) optionally, an epoxy curing accelerator. Generally, in
determining the quantity of curing agent, e.g.,
phenolic-formaldehyde novolac and the condensates of this
invention, the hydroxyl equivalence should be about 0.8 to 1.1
parts of hydroxyl equivalent for each epoxy equivalent.
[0086] The N-substituted arylamino-phenol-formaldehyde condensates
of this invention can be used alone as both the curing agent and to
impart flame-retardant properties to the epoxy resin.
Alternatively, the N-substituted arylamino-phenol-formaldehyde
condensates can be used together with one or more conventional
epoxy resin curing agents and/or flame-retardant agents.
[0087] A variety of additional curing agents well known in the art
can be used together with the N-substituted
arylamino-phenol-formaldehyde condensates of this invention in
curing the epoxy resin. They include but are not limited to
aromatic amines, polyamidoamines; polyamides; dicyandiamide;
phenolic-formaldehyde novolacs; melamine-formaldehyde resins;
melamine-phenolic-formaldehyde resins; and
benzoguanamine-phenolic-formaldehyde resins.
[0088] Reactive diluents may also be present in the epoxy
compositions to lower viscosity and improve handling
characteristics. Examples of reactive diluents include
neopentylglycol diglycidyl ether; butanediol diglycidyl ether;
resorcinol diglycidyl ether; and cyclohexane dimethanol diglycidyl
ether.
[0089] In order that those skilled in the art may more fully
understand the invention presented herein, the following procedures
and examples are set forth. Unless otherwise indicated, the
following units of measurement and definitions apply in this
application unless otherwise indicated: all parts and percentages
are by weight; temperatures are in degrees centigrade (.degree.
C.); use of oxalic acid is as the dihydrate; and readings of vacuum
are in inches of mercury. The designator "Ex" in the Tables is the
abbreviation for examples.
DETAILED DESCRIPTION
EXAMPLES 1 and 2
[0090] Preparation of N-Ethylaniline-Phenol-Formaldehyde
Condensates
[0091] These examples were conducted in a manner similar to Example
3 described below except to the extent shown in Table 1A
herein.
EXAMPLE 3
[0092] Preparation of N-Ethylaniline-Phenol-Formaldehyde
Condensates
[0093] A one liter flask was charged with 301.2 g phenol (3.2
moles) and 194 g. N-ethylaniline (1.6 moles). The reaction mixture
was heated to 70.degree. C. and then 192 g 50% formalin (3.2 moles)
was added over 45 minutes at 70-72.degree. C. After 11/2 hours at
71-73.degree. C., 4 g acetic acid was added. The temperature was
raised to 80.degree. C. and maintained at 80.degree. C. for 2
hours. The temperature was raised to 100.degree. C. and maintained
for 11/2 hour. Reaction mixture was then atmospherically distilled
to 160.degree. C. to collect 156 g distillate. Phenol (92.1 g) was
then recovered by vacuum distillation increasing temperature to
190.degree. C. while increasing vacuum to 30 inches of mercury.
Product yield was 432.7 g and is characterized in Table 1B.
EXAMPLES 4 THROUGH 15
[0094] These examples were run by the Standard Method in the same
manner as Example 3, except to the extent shown in Table 1A
herein.
EXAMPLE 16
[0095] Preparation of N-ethylaniline-o-Cresol-Formaldehyde
Condensates
[0096] This example was performed in the same way as Example 7
except that 3.2 moles o-cresol was substituted for the phenol.
After heating at 100.degree. C., an atmospheric distillate was
taken and showed no free formaldehyde. Analysis of the product
showed 0.05% o-cresol; 4.79% of nitrogen, Mw/Mn of 670/421; and
viscosity at 150.degree. C. of 297 cps.
[0097] It can be seen from the above Example 16 that substitution
of phenol by o-cresol (Ex. 7) leads to a dramatic decrease in Mw
and viscosity with the expected small decrease in percent
nitrogen.
EXAMPLE 17
[0098] This example was run in the manner of Example 3 except to
the extent shown in Table 2A herein.
EXAMPLES 18 AND 20
[0099] These examples were run by the Standard Method in the same
manner as Example 3, except to the extent shown in Table 2A
herein.
EXAMPLE 19
[0100] Preparation of N-Methylaniline-Phenol-Formaldehyde
Condensates
[0101] A one liter flask was charged with 376.4 g phenol (4.0
moles), 171.5 g N-methylaniline (1.6 moles) and 7.0 g 90% formic
acid. The reaction mixture was heated to 70.degree. C. and then 191
g 50% formalin (3. 2 moles) was added at 70.degree. C. over 1 hour.
The temperature was maintained at 70.degree. C. for 2 hours at
which time the percent free phenol was determined to be 34.8% (vs.
50. 5% for no reaction of phenol). The temperature was raised to
100.degree. C. and maintained at 100.degree. C. for one hour at
which time the percent free phenol was 33.6%. Reaction mixture was
then atmospherically distilled to 160.degree. C. to collect 163 g
distillate. Phenol (170 g) was then recovered by vacuum
distillation increasing temperature to 190.degree. C. while
increasing vacuum to 30 inches of mercury. Product yield was 397 g
and is characterized in Table 2B and Table 5.
EXAMPLES 21 and 22
[0102] Examples 21, 22, and 24 were run by the Reverse Method such
as Example 23, except to the extent shown in Table 3A.
EXAMPLE 23
[0103] Preparation of N-Methylaniline-Phenol-Formaldehyde
Condensates Via the Reverse Method
[0104] A one liter flask was charged with 244.7 g phenol (2.6
moles) and 86.1 g 50% formalin (1.44 moles). The reaction mixture
was heated to 60.degree. C. and then 85.8 g N-methylaniline (0.8
mole) and added over 30 minutes at 60.degree. C. The temperature
was lowered to 50.degree. C. and 86.1 g 50% formalin (1.44 moles)
quickly added. The temperature was raised to 55.degree. C. and than
85.7 g N-methylaniline (0.8 mol) added over 32 minutes at
55-60.degree. C. After 20 minutes at 60.degree. C. the temperature
raised to 100.degree. C. and maintained at 100.degree. C. for one
hour. Reaction mixture was then atmospherically distilled to
160.degree. C. to collect 136.8 g distillate. Phenol (56.3 g) was
then recovered by vacuum distillation increasing temperature to
190.degree. C. while increasing vacuum to 30 inches of mercury.
Vacuum was broken and 100 ml deionized water added over 40 minutes
at about 190.degree. C. Vacuum was then applied to remove water at
190.degree. C. under 30 inches of mercury. Product yield was 372 g
and is characterized in Table 3B and Table 5.
EXAMPLE 24
[0105] This example was run in the same manner as Example 23 except
to the extent shown in Table 3A herein.
EXAMPLE 25
[0106] Preparation of N-Ethylaniline-Phenol-Formaldehyde
Condensates Via the Reverse Method
[0107] A one liter flask was charged with 376.4 g phenol (4.0
moles) and 95.4 g 50.3% formalin (1.6 moles). The reaction mixture
was heated to 50.degree. C. and then 96.8 g N-ethylaniline (0.8
mole) added over 35 minutes at 50-52.degree. C. After 30 minutes at
50.degree. C. the percent free phenol was 41.4% (vs. 66.2% if no
phenol reacted). 95.4 g 50.3% formalin (0.6 mole) was then added.
Then 96.8 g N-ethylaniline (0.8 mole) was added over 1/2 hour at
50.degree. C. This temperature was maintained for 73 minutes,
whereupon 7.0 g 90% formic acid was added. After 15 minutes the
temperature was raised to 100.degree. C. and maintained at
100.degree. C. for 1 hour. Atmospheric distillate (163 g) phenol
(149 g) and product (443. g) were recovered as described in Example
23 above. Product is characterized in Table 3B and Table 5.
EXAMPLE 26
[0108] Preparation of
N-Ethylaniline-N-Methylaniline-Phenol-Formaldehyde Condensates
[0109] A one liter flask was charged with 376.4 g of phenol (4. 0
moles), 96.8 g N-ethylaniline (0.8 mole), 85.6 g N-methylaniline
(0.8 mole) and 7.0 g. 90% formic acid. The reaction mixture was
heated to 70.degree. C. and then 191.0 g. of 50% formalin (3.2
moles) was added over 60 minutes at 70-72.degree. C. After 2 hours
at 70.degree. C. the percent free phenol determined gas
chromatographically was 31.5% (vs. 57.3% for no reaction of
phenol). The temperature was raised to 100.degree. C. and
maintained at 100.degree. C. for one hour at which time the percent
phenol was determined to be 30.6%. Reaction mixture was then
atmospherically distilled to 160.degree. C. to collect 165 g.
distillate. Phenol (165 g.) was then recovered by vacuum
distillation increasing temperature to 190.degree. C. while
increasing vacuum to 30" inches of mercury. When phenol appeared to
stop distilling over, vacuum was broken and 67 ml. of deionized
water added over 50 minutes at about 190.degree. C. Vacuum was then
applied to remove water at 190.degree. C. under 30 inches of
mercury vacuum. Product yield was 406.3 g and was characterized by
phenol, 0.65%; nitrogen, 5.53%; Mw/Mn, 1190/327; viscosity, 426 cps
(175.degree. C.) and in Table 5.
EXAMPLE 27
[0110] Preparation of
N-Ethylaniline-N-Methylaniline-Phenol-Formaldehyde Condensates
[0111] This example was conducted in a similar manner as Example 26
above except that phenol and formalin was added in 2 stages: 169.4
g phenol (1.80 moles) was charged initially and 96.5 g 50% formalin
(1.60 moles) added to the reaction mixture over 25 minutes. After
85 minutes at 70.degree. C. 132 g phenol (1.4 moles) was added
followed by 1.6 moles 50% formalin at 70-75.degree. C. over 30
minutes, Product was characterized by phenol, 0.44%; nitrogen,
6.08%; Mw/Mn, 1673/613; viscosity, 852 cps (175.degree. C.).
[0112] This example shows that addition of phenol and formalin in
two stages vs. one stage (Ex. 26) leads to higher Mw and
viscosity.
EXAMPLE 28
[0113] Preparation of N-Methylaniline-Phenol-Formaldehyde
Condensates Using Paraformaldehyde and 50% Formalin
[0114] A 500 ml flask was charged with 150.6 g phenol (1.6 moles)
and 85.8 g N-methylaniline(0.8 mole). To the reaction mixture at
33.degree. C. was added 13.2 g. paraformaldehyde (0.4 moles). The
reaction mixture was maintained at 31-40.degree. C. for 56 minutes
and another 13.2 g paraformaldehyde added (total now 0.8 moles).
The reaction mixture was maintained at 42-58.degree. C. during the
course of 8 hours. Reaction mixture was essentially homogeneous.
The percent unreacted phenol at this time was 57.0% (vs. 57.3% if
no phenol reacted) and the percent water was 6.9%. Then 24 g 50%
formalin (0.4 moles) was added over 23 minutes at 56-62.degree. C.
After 31/2 hours at 57-64.degree. C. 279 g (3% loss) reaction
mixture was transferred to another flask. Then at 55.degree. C.
23.2 g 50% formalin (0.14 moles) was added over 14 minutes at
55-60.degree. C. The reaction was heated 2 hours at 60.degree. C.
and 2 hours at 100.degree. C. Atmospheric distillate (51.2 g),
recovered phenol (35.8 g) and product (208.2 g) were isolated as
described in Example 3 above. Product was characterized by Mw/Mn,
1642/516; viscosity of 630 cps at 180.degree. C. and 6290 cps at
154.degree. C.
EXAMPLE 29
[0115] Preparation of N-Ethylaniline-N,N'-Dimethyl
Benzidine-Phenol-Formal- dehyde Condensates
[0116] This example may be conducted in a similar manner as Example
3 above except that 0.32 moles of N-ethylaniline can be replaced by
0.32 mole N,N'-dimethylbenzidine.
EXAMPLE 30
[0117] Preparation of N-Methylaniline-Phenol-m-Cresol-Formaldehyde
Condensate
[0118] This example may be conducted in a similar manner as Example
23 above except that 0.6 moles of phenol can be replaced by 0.6
mole m-cresol.
EXAMPLE 31
[0119] Preparation of
N-Ethylaniline-N-Methylaniline-Phenol-Acetaldehyde-F- ormaldehyde
Condensate
[0120] This example may be conducted in a similar manner as Example
26 above except that 0.32 moles of formaldehyde an be replaced by
0.32 mole acetaldehyde. The acetaldehyde is added prior to the
formaldehyde.
EXAMPLE 32
[0121] Preparation of N-Etliylaniline-Phenol-Formaldehyde
Condensate Using Methyl Carbitol Solvent
[0122] This example may be conducted in a similar manner as Example
25 above except that 75 g phenol (0.8 moles) is replaced by 75 g
methyl carbitol (monoethyl ether of diethylene glycol). Unreacted
phenol and solvent is recovered by vacuum distillation, which is
followed by steam sparging and drying.
EXAMPLE 33
[0123] Preparation of -N-Methylaniline-Phenol-Formaldehyde
Condensate-Post Addition of Triethylamine
[0124] This example may be conducted in a manner similar to Example
23 above except that 2.4 g triethylamine is added immediately after
the second addition of N-methylaniline.
EXAMPLE 34
[0125] Preparation of N-Ethylaniline-Phenol Formaldehyde Condensate
with Initial Addition of Triethylamine (Method 5)
[0126] A one liter flask was charged with 301.1 g (grams) of phenol
(3.2 moles) 194 g N-ethylaniline, and 3.01 g triethylamine. pH's of
the reaction mixture were 7.34 and 8.80 before and after addition
of the amine, respectively. The reaction mixture was heated to
80.degree. C. and then 191.4 g of 50.3% formalin (3.2 moles) was
added over 1 hour at 80.degree. C. A temperature of 80.degree. C.
was maintained for 2 hours and the pH was 8.01. Percent phenol
taken 5 minutes* after addition of formaldehyde and post 2 hours at
80.degree. C. was essentially constant, that is 12.4% plus or minus
0. 1%. This indicated 72% reaction of the phenol. *The phenol taken
after 5 minutes had an alloquot heated for 2 hours at 95.degree. C.
in the presence of 2% formic acid and the molecular weight Mw/Mn
was found to be 959/432. The temperature was raised to 100.degree.
C. and maintained for 1 hour. At this time the % phenol was 164%
(74% conversion) and the pH was 8.47. Atmospheric distillate (294.7
g), phenol vacuum distillate (64.5 G) and product (433.5 g) were
recovered as described in Example 23 above. Product was
characterized by phenol 0.5%; 4.87% nitrogen; Mw/Mn, 893/409;
viscosity, of 589 cps (150.degree. C.), and a Methanol Tolerance of
332%.
EXAMPLE 35
[0127] Preparation of N-Ethylaniline-Phenol Formaldehyde Condensate
Using the Method of Method 6
[0128] A reactor is charged with 376.4 g phenol (4 moles) and 95.5
g 50% formalin (1.6 moles). This reaction mixture is heated to
60.degree. C. whereupon 96.8 g N-ethylaniline (0.8 moles) is added
at 60.degree. C. over 40 minutes. The reaction mixture is then
heated at 80.degree. C. for 1 hour and then 1 hour at 100.degree.
C. to substantially completely react the phenol. The reaction
mixture is cooled to 70.degree. C. Then 96.8 g of N-ethylaniline
(0.8 moles) is added followed by addition of 95.5 g of 50% formalin
(1.6 moles) at 70.degree. C. over 45 minutes. This reaction mixture
is then heated at 80.degree. C. for 2 hours and at 100.degree. C.
for 1 hour. Atmospheric distillate, phenol and product are removed
as described in Example 23 above. In a similar manner 85.6 g of
N-methylaniline (0.8 moles) may be substituted for the 96.8 g of
N-ethylaniline (0.8 moles) in the first reaction stage (i.e.
Reverse Method) to give a
N-ethylaniline-N-methylaniline-phenol-formaldehyde condensate.
COMPARATIVE EXAMPLE 1
[0129] Attempted Reaction of Phenol and Formaldehyde Using Tertiary
Aromatic Amine
[0130] A 250 ml flask was charged with 75.3 g phenol (0.8 mole) and
24 g N,N-dimethyl-p-toluidine. The mixture was heated to 70.degree.
C. and 23.7 g 50.2% formalin (0.4 mole) added over 17 minutes. The
percent free phenol at this time was 58.4%, which corresponds to 5%
reaction. After heating one hour at 70.degree. C. the percent free
phenol was 54.6%, which corresponds to 11% reaction. Eighteen
minutes later the temperature was reduced to 60.degree. C. and 0.75
g triethylamine added. The temperature was raised to 70.degree. C.
and maintained for one hour. The percent free phenol was 38.4%,
which corresponds to 37% reaction.
[0131] N,N-dimethyl-p-toluidine of Comparative Example 1 which can
be considered a model for N-alkylation and para aminoalkylation
reactions has a pH basicity of 7.24 which is significantly stronger
than N-methylaniline (PK 4.85) or N-ethylaniline (pK 5.11). Despite
the higher basicity it showed little catalytic activity for the
reaction of formaldehyde and phenol at 70.degree. C. In contrast,
the considerably stronger triethylamine (pK 10.72) led to
significant reaction after one hour at 70.degree. C.
COMPARATIVE EXAMPLE 2
[0132] Attempted Reaction of N,N-Diethylaniline with Formaldehyde
in Diglyme
[0133] A 250 ml flask was charged with 75 g N,N-diethylaniline (0.5
mole) and 75 g diglyme (2-methoxyethyl ether). The mixture was
heated to 70.degree. C. and 15 g 50% formalin added over 10
minutes. No exotherm was observed. A temperature of 70-72.degree.
C. was maintained for one hour and then the temperature was raised
to 80.degree. C. After one hour at 80.degree. C. the temperature
was raised to 100.degree. C. and then maintained at 100.degree. C.
for one hour. Very little reaction was observed after the one hour
intervals at temperatures of 70.degree. C., 80.degree. C. and
100.degree. C.
[0134] The Tertiary aromatic amine N,N-diethylaniline of the above
Comparative Example 2 lacks the --NH site present in N-ethylaniline
and therefore shows essentially no reactivity with formaldehyde, at
least in the absence of phenol. In contrast, N-ethylaniline
exhibits exotherm activity with formaldehyde over the entire
temperature range 30.degree. C. to 100.degree. C. Attack at the
para position of N,N-diethylaniline would be possible with methylol
phenol or N-methylol aniline intermediates.
1TABLE 1A Preparation of N-Ethylaniline-Phenol-Form- aldehyde
(E-P-F) Condensates via the Standard Method Reaction Moles Add
Temp., .degree. C. Conditions, Ex. P.sup.(e) E.sup.(f) F.sup.(g)
Acid (%).sup.(a) hrs/.degree. C..sup.(b) Reference 1 0.8 0.4 0.8
30-33.degree. C. AA (1.33) 1.5/70, 2/80, 2540-26 @ 80.degree. C.
0.5/100 2 3.2 1.6 3.2 50-52.degree. C. AA (1.33) 1.5/70, 2/80,
2457-37 @ 80.degree. C. 0.5/100 3 3.2 1.6 3.2 70.degree. C. AA
(1.33) 1.5/70, 2/80, 2457-41 @ 80.degree. C. 0.5/100 4 3.2 1.6 2.9
70.degree. C. FA (2.09) 1.5/70, 2/80, 2540-42 0.5/100 5 3.2 1.6 3.2
70.degree. C. FA (2.09) 2/70, 1/100 2540-39 6 3.2 1.6 3.2
70.degree. C. FA (0.33) 2/70, 1/100 2540-43 7 3.2 1.6 3.2
82.degree. C. FA (2.09) 2/80, 1/100 2544-20 8 3.2 1.6 3.2
100.degree. C. FA (2.09) 2/100 2540-46 9 3.2 1.6 3.2 60.sup.(c)
.degree. C. OX (2.29) 1/100 2540-37 10 3.2 1.6 3.2 70.sup.(d)
.degree. C. OX (2.29) 0.5/100 2540-35 11 4.0 1.6 3.2 70.degree. C.
None 1.5/70, 2/80, 2547-49 0.5/100 12 4.0 1.6 3.2 70.degree. C. AA
(1.06) 1.5/70, 2/80, 2547-42 0.5/100 13 4.0 1.6 3.2 70.degree. C.
AA (1.06) 1.5/70, 2/80, 2547-43 @ 80.degree. C. 0.5/100 14 4.8 1.6
3.2 70.degree. C. OX (1.53) 2/70, 1/10 2540-33 15 4.8 1.6 3.2
70.degree. C. OX (100) 1.5/70, 2/80, 2547-51 @ 100.degree. C.
0.5/100, distilled to 100.degree. C., 1/100, 1/110 .sup.(a)AA =
acetic acid, FA = 90% formic acid, OX = oxalic acid 2H2O. Percent
acid in parentheses by weight on phenol weight. When the acid was
added prior to the addition of formaldehyde, the first set of
temperature readings give the temperature of the reaction mixture
containing the acid when the formaldehyde was added; however, when
the acid was added after the addition of the formaldehyde, the
temperature of the reaction mixture #when the acid was # added is
prefixed with the @ notation and the first set of temperature
readings are that of the reaction mixture when the formaldehyde was
added. .sup.(b)After addition of formaldehyde. .sup.(c)1/2 of F
added over 50 minutes vacuum dry to 75.degree. C., remainder of F
added over 50 minutes at 60.degree. C., react 30 minutes and vacuum
dry to 75.degree. C. .sup.(d)1/2 of F added over 40 minutes, vacuum
dry to 75.degree. C., react one hour at 70.degree. C., add
remainder of F over 40 minutes at 70.degree. C., react 35 minutes
at 70.degree. C., vacuum dry to 80.degree. C. .sup.(e)P is phenol.
.sup.(f)E is N-ethylaniline. .sup.(g)F is formaldehyde.
[0135] Properties of N-Ethylaniline-Phenol-Formaldehyde Condensates
The below table shows: the percent of free (unreacted) phenol in
the condensate; the amount of nitrogen combined in the condensate,
the weight molecular weight (Mw), the number molecular weight (Mn)
and viscosity in centipoise at the indicated temperatures.
2TABLE 1B Ex. Phenol, % N, % Mw/Mn Viscosity, cps (.degree. C.) 1
0.93 5.34 2572/634 6715 (150.degree.) 2 0.98 5.11 1821/553 2370
(154.degree.) 3 1.15 5.17 1478/510 1134 (154.degree.) 4 0.65 5.20
991/482 1007 (150.degree.) 5 1.26 5.44 893/474 1386 (150.degree.) 6
0.48 4.65 1022/468 1205 (150.degree.) 7 0.14 5.39 878/469 1136
(150.degree.) 8 -- 5.61 1726/614 1829 (175.degree.) 9 -- 5.48
774/462 1633 (175.degree.) 10 -- 5.46 618/416 1030 (175.degree.) 11
0.12 4.91 791/393 380 (175.degree.) 12 0.11 5.40 1215/498 1200
(175.degree.) 13 1.5 (0.2).sup.(a) 4.97 904/423 510 (840).sup.(a)
(154.degree.) 14 1.3 5.02 861/443 727 (150.degree.) 15 0.06 4.78
597/350 215 (154.degree.)
[0136]
[0137] From the results in Tables 1A and 1B it can be seen
that:
[0138] 1. Increasing the temperature (30.degree. C. to 70.degree.
C.) when formaldehyde is added leads to a marked decrease in Mw and
viscosity with essentially no change in percent nitrogen (Ex's
1-3).
[0139] 2. Addition of formic acid initially (Ex. 5) versus adding
acetic acid after addition of formaldehyde(Ex. 3) results in a
significant decrease in Mw but little effect on viscosity.
[0140] 3. Reduction of formic acid (Ex. 6 vs. Ex. 5) has only a
marginal effect on Mw and viscosity.
[0141] 4. Addition of formaldehyde at elevated temperature
(100.degree. C., Ex. 8) vs. 70.degree. C. (Ex. 5) leads to a
significant increase in Mw and viscosity.
[0142] 5. Use of oxalic acid (Exs. 9, 10) versus formic acid (Exs.
3, 5-7) leads to a significant decrease in Mw but an increase in
viscosity (considering differences in viscosity temperature).
[0143] 6. Deletion of acetic acid (Ex. 11) vs. Ex. 12 leads to a
significant decrease in Mw and viscosity.
[0144] 7. Post formaldehyde addition of acetic acid (at 80.degree.
C., Ex. 13) vs. addition prior to formaldehyde (Ex. 12) leads to a
significant decrease in Mw and viscosity.
[0145] 8. Increasing the phenol/N-ethylaniline ratio (Ex. 12 vs.
Ex. 3) doe not lead to a dramatic effect on properties.
[0146] 9. Post formaldehyde addition of oxalic acid (Ex. 15 vs. Ex.
14) at 100.degree. C. leads to a significant decrease in Mw and
viscosity.
[0147] 10. It can be seen that substitution of phenol by o-cresol
(Ex. 7) leads to a dramatic decrease in Mw and viscosity with the
expected small decrease in percent nitrogen. 3
3TABLE 2A (Preparation of) N-Methylaniline-Phenol-F- ormaldehyde
(M-P-F) Condensates via The Standard Method Reaction Moles Add
Temp., .degree. C. Conditions, Ex. P.sup.(e) E.sup.(f) F.sup.(g)
Acid (%).sup.(a) hrs/.degree. C..sup.(b) Reference 17 2.4 1.6 2.88
70.degree. C. FA (3.10) 2/70, 1/100 2487-99 18 3.2 1.6 3.2
70.degree. C. FA (2.09) 2/70, 1/100 2457-64 19 4.0 1.6 3.2
70.degree. C. FA (2.09) 2/70, 1/100 2457-79 20 5.0 1.0 3.6
70/100.sup.(c) .degree. C. FA (1.49) 3.5/100 2457-96
[0148]
4TABLE 2B Properties of N-Methylaniline-Phenol-Form- aldehyde
Condensates Ex. Phenol, % N, % Mw/Mn Viscosity, cps (.degree. C.)
17 -- 6.66 2431/709 6095 (175.degree.) 18 0.75 5.42 3234/811
>8100 (180.degree.) 19 0.52 5.12 1638/597 7330 (175.degree.) 20
0.81 3.27 2606/751 2291 (175.degree.)
[0149] From the results in Tables 2A and 2B, it can be seen
that:
[0150] 1. Substitution of N-ethylaniline (Ex. 5) by N-methylaniline
(Ex. 18) leads to a very large increase in Mw and particularly in
viscosity.
[0151] 2. All three mole ratios (Exs. 17-19) gave relatively high
Mw and viscosity but with a wide range in percent nitrogen. 5
5TABLE 3A (Preparation of N-Alkylaniline-Phenol-For- maldehyde)
Condensates via The Reverse Method.sup.(a) In the following Table
3A, "P" stands for phenol, "E" stands for N- ethylaniline, "M"
stands for N-methylaniline; and "F" stands for formaldehyde. The
percent of added acid is based on the weight of phenol charged.
Reaction Moles Conditions, Ex. P E M F Acid (%).sup.(a)
hrs/.degree. C..sup.(b) Reference 21 2.4 -- 1.6 2.88 FA (3.10)
0.5/50, add acid, 2457-101 1/100 22 2.6 -- 1.6 2.88 FA (2.86)
0.5/60, add acid, 2457-105 1/100 23 2.6 -- 1.6 2.88 NONE 0.5/60,
1/100 2457-104 24 4.0 -- 1.6 3.2 FA (1.86) 1/50, add acid, 2540-45
1/100 25 4.0 1.6 -- 3.2 FA (1.86) 1/50, add acid, 2457-86 1/100
.sup.(a)N-alkylaniline added to phenol-formaldehyde mixture at
50.degree. C. (Exs. 21, 24, 25) or at 60.degree. C. (Exs. 22, 23)
.sup.(b)90% formic acid (FA) added after addition of
N-alkylaniline.
[0152]
6TABLE 3B Properties of N-Methylaniline-Phenol-Form- aldehyde
Condensates Ex. Phenol, % N, % Mw/Mn Viscosity, cps (.degree. C.)
21 -- 5.97 1414/456 944 (175.degree.) 22 -- 5.81 1430/440 616
(175.degree.) 23 0.19 5.81 1157/433 404 (175.degree.) 24 -- 5.26
908/395 1832 (175.degree.) 25 0.65 4.96 973/429 858
(150.degree.)
[0153] It can be seen from the results in Table 3A and 3B that:
[0154] 1. The Reverse Method with N-methylaniline (Ex. 21) compared
to the Standard Method (Ex. 17) affords greatly reduced Mw and
viscosity.
[0155] 2. Omission of formic acid (Ex. 23 vs. Ex. 22) leads to a
significant decrease in Mw and viscosity.
[0156] 3. Substitution of N-methylaniline (Ex. 24) by
N-ethylaniline (Ex. 25) has essentially no effect on Mw but
significantly reduces viscosity.
[0157] 4. Example 19, as shown in Table 2B was performed under
substantially the same conditions as Example 24 of Table 3B.
However, it can be seen that Example 24 which used the Reverse
Method produced condensate having lower viscosity.
[0158] It can be seen from Tables 1B, 2B, and 3B that the Reverse
Method provides lower molecular weights and lower viscosities as
compared to the Standard Method. 7
7TABLE 4 pH of Reaction Mixture Ex. Time Sampled pH Reference 1
After 1/2 of formaldehyde added 7.28 2540-26 1 1/3 hours after
acetic acid added 6.03 4, 5 Immediately before and after addition
7.09/5.1 2540-39, 42, 43 of formic acid 14 After 1/2 of
formaldehyde added 5.6 2540-33 2/3 hours after formaldehyde added
5.6 34 Before triehylamine is added 7.3 Before formaldehyde is
added 8.8 After formaldehyde is added 8.0
[0159]
8TABLE 5 Application Results In the below table, HPC, i.e., hot
plate cure, as well as the other headings in the table are
determined in accordance with the methods set forth herein. HPC,
sec. Adhesion Impact Methanol Ex. (c) (d) (c) Resistance (c)
Tolerance % Durite SD-1732 192 Pass (P) P, F.sup.(a) Infinite
(control) Fail (F).sup.(a) Durite SD-1708 Infinite (control) 7 82 8
38 F F <5 17 <5 18 -- -- P <5 19 -- P P 23 22 45 F,
F.sup.(b) F, F.sup.(b) 23 23 41 (36).sup.(b) F, F.sup.(b) F,
F.sup.(b) 46 24* 46 P P 210 25 59 P P 667 26 59 P P 73 34 F,
F.sup.(a) (b) F, F.sup.(b) 332 *Essentially similar results can be
obtained by substituting 0.5 g of 5% 2-methylimidazole by 2 grams
of 59% solution of the condensate of Example 24 to cure the D.E.R.
383 epoxy resin. Although this would not be an effective curing
agent it would be an effective accelerator. .sup.(a)Approximately
50% tests failed .sup.(b)0.8 Hydroxyl equivalent used per one epoxy
equivalent. .sup.(c)Conducted in Formulation of Condensate with
Epoxy Resin. .sup.(d)sec in the above table refers to seconds.
[0160] It can be seen from Table 5 that:
[0161] 1. The condensates of this invention cure much faster, up to
5.times., than phenol novolac Durite SD-1732. In the absence of
2-methylimidazole accelerator condensates of this invention cure in
less than 1/2 the time of SD-1732 with accelerator.
[0162] 2. A wide range in Methanol Tolerance is observed with
particularly high values exhibited by N-ethylaniline condensates
(Exs. 24, 25) prepared by the Reverse Method.
[0163] 3. A number of condensates (Exs. 19, 24-26) exhibit superior
adhesion and impact resistance than Durite SD-1732.
[0164] 4. The level of condensate curative (Ex. 23) affects
adhesion and impact resistance. The lower level (0.8 OH equivalent
per epoxy) showing the superior performance as well as faster
cure.
[0165] 5. The Reverse Method gives higher Methanol Tolerance.
[0166] 6. The very great difference in Methanol Tolerance of the
condensates of the instant invention is surprising and unexpected
in light of the infinite Methanol Tolerance of the
phenol/formaldehyde controls which span the molecular weight Mw of
about 950 for Durite SD-1752 and 2500 for Durite SD-1708.
[0167] Determination of Hydroxyl Equivalent
[0168] This procedure involves a known weight of sample which is
refluxed with excess acetic anhydride in pyridine. Subsequently,
unreacted anhydride is destroyed by reaction with water. The
resulting mixture is titrated with 0.1N NaOH. The result is
compared to a blank (i. e., no resin).
[0169] When the above procedure was conducted with several resins
of the instant invention very misleading results (OH numbers of ca.
120-130), i.e., irreconcilable with material balance of reactants,
were obtained. Erroneous results were likewise obtained with a
model material (Ancamine 1110, N,N-dimethylaminomethyl phenol, a
product of Air Products and Chemicals, Inc.) wherein a value about
1/3 of theory was obtained.
[0170] Hydroxyl equivalent was calculated from product yield
(grams) by determining phenol content after subtracting the
contribution of N-substituted arylamine and methylene (fragment
resulting from formaldehyde). In this manner hydroxyl equivalents
of about 195 to about 220 were obtained.
[0171] Determination of Melt Viscosities
[0172] Viscosities, at 175.degree. C., were determined with a cone
and plate viscometer from Research Equipment (London) Ltd. Number
40 and 100 spindles were used depending on the viscosity reading. A
factor multiplier of 300 was used for the Number 40 spindle and a
factor multiplier of 800 was used for the of 100 spindle values
shown from digital readout. For example, a digital reading of 20
obtained with a #40 cone spindle would be multiplied by 300 to give
a viscosity value of 600 cps. Viscosities, at 150.degree. C., were
determined the same way as for 175.degree. C. except that the No.
40 spindle has a factor of 330 and the No. 100 spindle has a factor
of 890.
[0173] Determination of pH of Reaction Mixtures
[0174] One gram of reaction mixture was diluted with 50 mis
methanol. pH was determined by using a single probe electrode pH
meter, previously calibrated at pHs of 4 and 7. Results are shown
in Table 4.
[0175] Determination of Methanol Tolerance (Methanol Tolerance
Method)
[0176] A solution prepared by dissolving equal parts by weight of
condensate of this invention and methanol is used in this
determination. To 3.0 g of such 50% solution was gradually added
methanol until a turbidity persisted at 25.degree. C..+-.1.degree.
C. Methanol Tolerance (%) was calculated from g methanol to
turbidity.times.100/3.0 g. Results for Methanol Tolerance are shown
in Table 5.
[0177] Determination of Solubility of N-substituted
arylamine-Phenol-Formaldehyde Condensates
[0178] Condensate with an equal weight of solvent was placed in a
jar, closed, placed in a 60.degree. C. oven and intermittently
shaken until dissolved. Upon cooling to room temperature a clear
solution resulted. Solvents so tested on Examples 21, 23, 25, 26,
and 27 were n-butanol, methyl isobutyl ketone, and
bis(2-methoxyethyl) ether (diglyme).
[0179] Formulation of Condensates of this Invention with Epoxy
Resin
[0180] The halogen free epoxy resin used was D.E.R. 383 a product
of Dow Chemical (Midland, Mich.) with weight per epoxy equivalent
of 189. N-substituted arylamine-phenol-formaldehyde condensates
were generally employed as a 59% solution in solvent (65 g resin,
35 g methyl ethyl ketone, 10 g Dowanol PM). The formulation, unless
indicated otherwise, was as follows:
9 D.E.R.383 12.5 g 59% resin solution 21-24 g* 5% 2-mehtylimidazole
in Dowanol PM 0.5 g *weight to provide one phenolic OH equivalent
per epoxy equivalent. For phenol-formaldehyde novolac Durite
SD-1732 (Borden Chemical, Louisville KY) with OH equivalent of 105
9.9 grams of 70% solution were used. The Mw of this resin is ca.
950. Resin and epoxy were thoroughly mixed prior to addition of the
imidazole. # Formulations when not used immediately (as for coating
or hot plate cures) were refrigerated. Use of triphenylphosphine
(ca. 1% on epoxy resin) as accelerator and phosphorus acid (ca. 3%
on epoxy resin) can further enhance fire retardancy of the cured
epoxy composition.
[0181] An additional gram of Dowanol PM was added to very viscous
formulations to facilitate dissolution of condensate and to
facilitate the draw-down of the coatings) this applies to Examples
17-19).
[0182] Coating and Curing of Epoxy Formulation
[0183] 4-5 mis of epoxy formulation were placed in front of a draw
down bar (opening of 6/8 inches) and a coating made by drawing down
on solvent cleaned (ethanol then MEK) copper sheet. Coatings were
air dried 1-2 hours at ambient temperatures followed by one hour
each at 60.degree. C., 100.degree. C. and 160.degree. C. Coating
thickness was generally 0.01".+-.0.015". All formulations with the
inventive condensate gave coatings which were tack-free at room
temperature after one hour at 60.degree. C. Formulations with
Durite SD-1732 were tacky to the touch. Furthermore, the SD-1732
coatings strongly had a mottled ("fisheye") appearance which was
not observed with coatings of the inventive condensates.
[0184] Adhesion Testing of Epoxy Formulation Coatings
[0185] 5/841 strips were cut from the cured coatings on copper
sheet. The strips were then bent 180.degree. around a rigid rod of
3/4" diameter. Cracking or peeling of the coating constituted a
failure (F). No change in coating constituted a pass (P). Tests
were conducted in at least duplicate. Results are shown in Table
5.
[0186] Impact Resistance Testing of Epoxy Coatings on Copper
[0187] The test was conducted as follows: Panels of cured epoxy
formulations on copper sheet were placed on a wood block. Then a
406 g weight (61/4" long) terminated with the top end of a 200 g
calibration weight was dropped through a 61/2' tube (1 {fraction
({fraction (3/16)})}" diameter) placed perpendicular to the panel
onto the back side of the coated panel. A cracking or rupture of
the coating at point of impact constituted a failure (F). No
cracking constituted pass (P). The test was conducted in duplicate.
Results are shown in Table 5.
[0188] Preparation of Laminates from Epoxy Formulation
[0189] Formulations used to coat copper sheet can be used to coat
glass cloth commonly used by laminators. The coated cloth is
allowed to air dry at room temperature for one hour, dried at
100.degree. C. for 1/2 hour. Tack-free strips are stacked into a
several ply sandwich. This configuration is then placed under
pressure between two metal plates preheated at 170.degree. C. for
11/2 hours. The resulting laminate can be trimmed and tested for
mechanical properties as well as for fire-retardancy.
[0190] Determination of Hot Plate Cure (HPC)
[0191] One gram of epoxy formulation is placed at the end of a
stainless steel spatula 1" in width. The liquid is then placed at
the center of a hot plate at 170.degree. C..+-.10.degree. C. After
several seconds allowing for evaporation of volatile solvents(s)
the mix is stroked with 1/2 the width of the spatula 1" to the
right and 1" to the left repeatedly on the hot plate. The mix
becomes transformed to a stringy mass. The time when the strings
break, i. e., no longer connect from the spatula to the hot plate,
is considered the cure time and is recorded in seconds. The test
was conducted in duplicate. Results are shown in Table 5.
[0192] Determination of Molecular Weights
[0193] The weight average molecular weight (Mw) and number average
molecular weight(Mn) herein are measured using size exclusion gel
permeation chromatography (SEC) and phenolic compounds and
polystyrene standards. The sample molecular weight to be measured
is prepared as follows: the sample is dissolved in tetrahydrofuran
and the solution is run through a gel permeation chromatograph. Any
free phenolic in the sample is excluded from calculation of
molecular weight. SEC as a measure of molecular weight is highly
dependant on the hydrodynamic volume of the material in solvent.
Highly branched or polycyclic materials tend to give lower values
than molecular weights determined by other means such as vapor
phase osmometry (VPO).
* * * * *