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Claims  |
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That which is claimed is:
1. A process for producing a resin which comprises contacting and reacting
essentially simultaneously
(A) an aliphatic polyhydric alcohol or a mixture of aliphatic polyhydric
alcohols;
(B) a polybasic carboxylic acid or an anhydride or mixtures thereof;
(C) an organosilane or a mixture of organosilanes having the general
formula
R.sub.n Si(OR').sub.4-n
wherein R is selected from a group consisting of phenyl, methyl, ethyl,
propyl and butyl radicals; R' is an alkyl radical of 1-4 carbon atoms and
n has a value of 1 or 2 and,
(D) at least a stoichiometric amount of water based on the amount of
--(OR') present in the mixture, at a temperature greater than 25.degree.
C. for a period of time sufficient to produce a resin with an acid value
of 10-150.
2. A process as claimed in claim 1 wherein the polyhydric alcohols are
selected from a group consisting of pentaerythritol, trimethylolethane,
trimethylolpropane, 2,3-dimethyl-1,3-propanediol, trimethylpentanediol,
ethyleneglycol, propyleneglycol, trimethyleneglycol, glycerin,
1,4-cyclohexanediol, tetramethyleneglycol, 1,4-cyclohexanedimethanol,
hexamethylene diol, 2-methyl-2-ethyl-1,3-propanediol,
2,2,7,7-tetramethyl-1,8-octamethylenediol, 1,2,6-hexanetriol, sorbitol,
diglycerine, tris(2-hydroxyethyl)isocyanurate and mixtures thereof.
3. A process as claimed in claim 2 wherein the polyhydric alcohols are
selected from a group consisting of 1,4-cyclohexanedimethanol,
trimethylpentanediol, trimethylolpropane, pentaerythritol, glycerine and
mixtures thereof.
4. A process as claimed in claim 1 wherein the polybasic carboxylic acids
and anhydrides are selected from a group consisting of phthalic acid,
phthalic anhydride, terephthalic acid, isophthalic acid,
2,6-naphthalenedicarboxylic acid, succinic acid, glutaric acid, adipic
acid, sebacic acid, tetrahydrophthalic acid, tetrahydrophthalic anhydride,
trimellitic anhydride, hexahydrophthalic anhydride,
##STR3##
where x is an integer of 1 to 10, and mixtures thereof.
5. A process as claimed in claim 4 wherein the polybasic carboxylic acid,
isophthalic acid, is mixed with trimellitic anhydride.
6. A process as claimed in claim 1 wherein there is also present a drying
oil fatty acid.
7. A process as claimed in claim 6 wherein the drying oil fatty acid is
selected from tall oil fatty acid, soybean oil fatty acid, castor oil
fatty acid, dehydrated castor oil fatty acid, coconut oil fatty acid,
linseed oil fatty acid, tung oil fatty acid, fish oil fatty acid, olive
oil fatty acid and cotton seed oil fatty acid.
8. A process as claimed in claim 7 wherein the drying oil fatty acid is
dehydrated castor oil fatty acid.
9. A process as claimed in claim 1 wherein component (C) is a mixture of
C.sub.6 H.sub.5 Si(OCH.sub.3).sub.3 and CH.sub.3 CH.sub.2 CH.sub.2
Si(OCH.sub.3).sub.3.
10. A process as claimed in claim 1 wherein component (C) is a mixture of
C.sub.6 H.sub.5 Si(OCH.sub.3).sub.3 and (C.sub.6 H.sub.5).sub.2
Si(OCH.sub.3).sub.2.
11. A process as claimed in claim 1 wherein component (C) is a mixture of
C.sub.6 H.sub.5 (CH.sub.3)Si(OCH.sub.3).sub.2 and CH.sub.3
Si(OCH.sub.3).sub.3.
12. A process as claimed in claim 1 wherein component (C) is a mixture of
C.sub.6 H.sub.5 Si(OCH.sub.3).sub.3 and CH.sub.3 Si(OCH.sub.3).sub.3.
13. A process as claimed in claim 1 wherein component (A) is a mixture of
1,4-cyclohexanedimethanol and trimethylolpropane; component (B) is a
mixture of isophthalic acid and trimellitic anhydride and component (C) is
a mixture of C.sub.6 H.sub.5 Si(OCH.sub.3).sub.3 and CH.sub.3 CH.sub.2
CH.sub.2 Si(OCH.sub.3).sub.3.
14. A process as claimed in claim 13 wherein in component (C), the mixture
contains 70 mole percent C.sub.6 H.sub.5 Si(OCH.sub.3).sub.3 and 30 mole
percent CH.sub.3 CH.sub.2 CH.sub.2 Si(OCH.sub.3).sub.3.
15. A resin produced by the process as claimed in claim 1.
16. A resin as claimed in claim 15 wherein there is an organic solvent
present.
17. A resin as claimed in claim 15 wherein there is water present as a
carrier.
18. A resin as claimed in claim 15 wherein the polyhydric alcohols are
selected from a group consisting of pentaerythritol, trimethylolethane,
trimethylolpropane, 2,3-dimethyl-1,3-propanediol, trimethylpentanediol,
ethyleneglycol, propyleneglycol, trimethyleneglycol, glycerin,
1,4-cyclohexanediol, tetramethyleneglycol, 1,4-cyclohexanedimethanol,
hexamethylene diol, 2-methyl-2-ethyl-1,3-propanediol,
2,2,7,7,-tetramethyl-1,8-octamethylenediol, 1,2,6-hexanetriol, sorbitol,
diglycerine, tris(2-hydroxyethyl)isocyanurate and mixtures thereof.
19. A resin as claimed in claim 18 wherein the polyhydric alcohols are
selected from a group consisting of 1,4-cyclohexanedimethanol,
trimethylpentanediol, trimethylolpropane, pentaerythritol, glycerine and
mixtures thereof.
20. A resin as claimed in claim 15 wherein the polybasic carboxylic acids
and anhydrides are selected from a group consisting of phthalic acid,
phthalic anhydride, terephthalic acid, isophthalic acid,
2,6-naphthalenedicarboxylic acid, succinic acid, glutaric acid, adipic
acid, sebacic acid, tetrahydrophthalic acid, tetrahydrophthalic anhydride,
trimellitic anhydride, hexahydrophthalic anhydride,
##STR4##
where x is an integer of 1 to 10, and mixtures thereof.
21. A resin as claimed in claim 20 wherein the polybasic carboxylic acid,
isophthalic acid, is mixed with trimellitic anhydride.
22. A resin as claimed in claim 15 wherein there is also present a drying
oil fatty acid.
23. A resin as claimed in claim 22 wherein the drying oil fatty acid is
selected from tall oil fatty acid, soybean oil fatty acid, castor oil
fatty acid, dehydrated castor oil fatty acid, coconut oil fatty acid,
linseed oil fatty acid, tung oil fatty acid, fish oil fatty acid, olive
oil fatty acid and cotton seed oil fatty acid.
24. A resin as claimed in claim 23 wherein the drying oil fatty acid is
dehydrated castor oil fatty acid.
25. A resin as claimed in claim 15 wherein component (C) is a mixture of
C.sub.6 H.sub.5 SiO.sub.3/2 units and CH.sub.3 CH.sub.2 CH.sub.2
SiO.sub.3/2 units.
26. A resin as claimed in claim 15 wherein component (C) is a mixture of
C.sub.6 H.sub.5 SiO.sub.3/2 units and (C.sub.6 H.sub.5).sub.2 SiO units.
27. A resin as claimed in claim 15 wherein component (C) is a mixture of
C.sub.6 H.sub.5 (CH.sub.3)SiO units and CH.sub.3 SiO.sub.3/2 units.
28. A resin as claimed in claim 15 wherein component (C) is a mixture of
C.sub.6 H.sub.5 SiO.sub.3/2 units and CH.sub.3 SiO.sub.3/2 units.
29. A resin as claimed in claim 15 wherein component (A) is a mixture of
1,4-cyclohexanedimethanol and trimethylolpropane; component (B) is a
mixture of isophthalic acid and trimellitic anhydride and component (C) is
a mixture of C.sub.6 H.sub.5 SiO.sub.3/2 units and CH.sub.3 CH.sub.2
CH.sub.2 SiO.sub.3/2 units.
30. A resin as claimed in claim 29 wherein in component (C), the mixture
contains 70 mole percent C.sub.6 H.sub.5 SiO.sub.3/2 units and 30 mole
percent CH.sub.3 CH.sub.2 CH.sub.2 SiO.sub.3/2.
31. A water reducible resin composition comprising
(a) from 20 to 90 parts by weight of a resin which is produced by
contacting and reacting essentially simultaneously
(i) an aliphatic polyhydric alcohol or a mixture of aliphatic polyhydric
alcohols:
(ii) a polybasic carboxylic acid or an anhydride or mixtures thereof;
(iii) an organosilane or a mixture of organosilanes having the general
formula
R.sub.n Si(OR').sub.4-n
wherein R is selected from the group consisting of phenyl, methyl, ethyl,
propyl and butyl radicals; R' is an alkyl radical of 1-4 carbon atoms and
n has a value of 1 or 2 and,
(iv) at least a stoichiometric amount of water based on the amount of
--(OR') present in the mixture, at a temperature greater than 25.degree.
C. for a period of time sufficient to produce a resin with an acid value
of 10-150,
(b) 80-10 parts by weight of a water-miscible organic solvent selected from
a group consisting of aliphatic alcohols, glycols, monoalkyl ethers of
glycols and ketones; and
(c) a basic compound selected from the group consisting of trimethylamine,
triethylamine, dipropylamine, dimethylethanolamine, diethylethanolamine,
triethanolamine and ammonia in an amount sufficient to reduce the acid
value of component (a) to below 10.
32. A resin composition as claimed in claim 31 wherein component (a)(i) is
selected from a group consisting of pentaerythritol, trimethylolethane,
trimethylolpropane, 2,3-dimethyl-1,3-propanediol, trimethylpentanediol,
ethyleneglycol, propyleneglycol, trimethyleneglycol, glycerin,
1,4-cyclohexanediol, tetramethyleneglycol, 1,4-cyclohexanedimethanol,
hexamethylene diol, 2-methyl-2-ethyl-1,3-propanediol,
2,2,7,7-tetramethyl-1,8-octamethylenediol, 1,2,6-hexanetriol, sorbitol,
diglycerine, tris(2-hydroxyethyl)isocyanurate and mixtures thereof.
33. A resin composition as claimed in claim 32 wherein component (a)(i) is
selected froom a group consisting of 1,4-cyclohexanedimethanol,
trimethylpentanediol, trimethylolpropane, pentaerythritol, glycerine and
mixtures thereof.
34. A resin composition as claimed in claim 31 wherein component (a)(ii) is
selected from a group consisting of phthalic acid, phthalic anhydride,
terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid,
succinic acid, glutaric acid, adipic acid, sebacic acid,
tetrahydrophthalic acid, tetrahydrophthalic anhydride, trimellitic
anhydride, hexahydrophthalic anhydride,
##STR5##
where x is an integer of 1 to 10, and mixtures thereof.
35. A resin composition as claimed in claim 34 wherein the polybasic
carboxylic acid, isophthalic acid, is mixed with trimellitic anhydride.
36. A resin composition as claimed in claim 31 wherein there is also
present a drying oil fatty acid.
37. A resin composition as claimed in claim 36 wherein the drying oil fatty
acid is selected from tall oil fatty acid, soybean oil fatty acid, castor
oil fatty acid, dehydrated castor oil fatty acid, coconut oil fatty acid,
linseed oil fatty acid, tung oil fatty acid, fish oil fatty acid, olive
oil fatty acid and cotton seed oil fatty acid.
38. A resin composition as claimed in claim 37 wherein the drying oil fatty
acid is dehydrated castor oil fatty acid.
39. A resin composition as claimed in claim 31 wherein component (a)(iii)
is a mixture of C.sub.6 H.sub.5 SiO.sub.3/2 units and CH.sub.3 CH.sub.2
CH.sub.2 SiO.sub.3/2 units.
40. A resin composition as claimed in claim 31 wherein component (a)(iii)
is a mixture of C.sub.6 H.sub.5 SiO.sub.3/2 units and (C.sub.6
H.sub.5).sub.2 SiO units.
41. A resin composition as claimed in claim 31 wherein component (a)(iii)
is a mixture of C.sub.6 H.sub.5 (CH.sub.3)SiO units and CH.sub.3
SiO.sub.3/2 units.
42. A resin composition as claimed in claim 31 wherein component (a)(iii)
is a mixture of C.sub.6 H.sub.5 SiO.sub.3/2 units and CH.sub.3 SiO.sub.3/2
units.
43. A resin composition as claimed in claim 31 wherein component (a)(i) is
a mixture of 1,4-cyclohexanedimethanol and trimethylolpropane; component
(a)(ii) is a mixture of isophthalic acid and trimellitic anhydride and
component (a)(iii) is a mixture of C.sub.6 H.sub.5 SiO.sub.3/2 units and
CH.sub.3 CH.sub.2 CH.sub.2 SiO.sub.3/2 units.
44. A resin composition as claimed in claim 43 wherein in component
(a)(iii), the mixture contains 70 mole percent C.sub.6 H.sub.5 SiO.sub.3/1
units and 30 mole percent CH.sub.3 CH.sub.2 CH.sub.2 SiO.sub.3/2 units. |
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Claims |
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Description |
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BACKGROUND OF THE INVENTION
This invention relates to a process for the preparation of stable,
silicone-alkyd copolymers which are useful intermediates in the
preparation of paints.
Alkyd resins have been used successfully as intermediates for formulating
outdoor paints, however, their weatherability is poor which requires
reapplication of the paints after a short period of time.
In order to improve their weatherability, alkyd resins have been modified
with silicones by blending or co-reacting. Better physical properties of
the co-reacted silicone modified alkyds led to the extensive use of such
materials as intermediates for paints.
The trend towards the use of silicone modified alkyds resulted in a number
of processes by which the silicone-modified alkyds could be co-reacted.
Some of these processes have been patented.
Typically, special care must be taken in the manner in which the alkyds and
the silicones are brought together in order to prevent gellation of the
materials. Two step and three step processes have evolved which may be
considered to be the standard by which silicone modified alkyds are
prepared.
For example, Goodwin et al. in U.S. Pat. No. 2,584,340, issued Feb. 5,
1952, describes a two step process in which a silane is first co-reacted
with a glycerine ester and the resulting silane-glycerine ester is further
reacted with a dibasic acid or anhydride. A similar two step process is
disclosed in U.S. Pat. No. 2,584,351, issued Feb. 5, 1952, wherein an
organosilane is condensed with a polyhydric alcohol and the condensation
product is then reacted with a polycarboxylic acid or its anhydride.
A further two step process is disclosed in British Pat. No. 740,265,
published Nov. 9, 1955, wherein a mixture of a fatty acid mono-ester of a
polyhydric alcohol and a free polyhydric alcohol are partly esterified by
using one or more polycarboxylic acids or ester-forming derivatives of
such acids. Thereafter, the remaining alcohol groups are condensed with
bi- or tri-functional organosilane monomers having alkoxy groups. A
similar approach can be found in Canadian Pat. No. 504,115, issued July 6,
1954.
Canadian Pat. No. 504,830 deals with a silicone modified alkyd which is
prepared by pre-forming the alkyd and then co-reacting it with a silanol
functional polysiloxane. Thus, there are three steps involved in such a
preparation. U.S. Pat. No. 3,015,637, issued Jan. 2, 1962, deals with the
type of three step reaction set forth above and in addition discloses that
the condensation of the pre-formed alkyd and the polysiloxane can be
enhanced by the use of titanium or zirconium compounds as catalysts.
U.S. Pat. Nos. 3,945,957 and 3,948,827, issued Mar. 23, 1976 and Apr. 6,
1976, respectively, disclose a dry planographic ink composition which is
prepared from a silicone modified alkyd resin which has been prepared by
pre-forming the alkyd and then condensing the alkyd with an
organopolysiloxane.
Finally, there is disclosed in U.S. Pat. No. 4,069,178, issued Jan. 17,
1978, that the troublesome gellation that often occurs with the heretofore
mentioned processes can be overcome by a special process wherein the major
portion of the carboxylic groups which are required in the alkyd are not
introduced until the final step of the process.
All of the disadvantages of the prior art methods have now been overcome by
the use of the process of the instant invention whereby the ingredients
necessary to form a silicone modified alkyd are all reacted together at
the same time without the necessity of preforming either the alkyd or the
silicone. The inventive process described below prevents the gellation
problems often encountered in the above-mentioned prior art processes and
yet the process provides silicone modified alkyd resins which have
excellent organic solvent and water resistance in the cured form and also
excellent weather resistance and gloss retention.
The resins prepared by the process of this invention have much narrower
dispersity of molecular weights than the resins prepared by the prior art
methods.
THE INVENTION
This invention deals with a novel one step process for preparing stable,
silicone modified alkyd resins which are useful in preparing formulated
paints.
The susceptibility of the co-reactants in the preparation of a silicone
modified alkyd to gel is highly dependent on the form of the silicone
compound used and the manner in which the co-reactants are brought
together. As a result, the alkyd is usually preformed by co-reacting
polyalcohols and carboxylic acids or anhydrides and then the alkyd is
further reacted with some form of silicone such as silanol functional or
alkoxy functional polysiloxanes. Occasionally, as can be observed from the
prior art discussion above, monomer silanes, usually alkoxy, acyloxy or
chlorosilanes are used. When the monomer silanes were used, however, it
was believed that they had to be pre-reacted with the carboxy groups of
dibasic acids or anhydrides before they could be coupled with the alcohols
of the alkyd or, it was believed the silane monomers had to be coupled
with the alkyd after the alkyd had been formed. U.S. Pat. No. 4,035,332,
issued July 12, 1977 and assigned to Shin-Etsu Chemical Co., Tokyo, Japan,
disclosed that silicone modified alkyds could be prepared in a true
one-shot process. In that U.S. patent, it was disclosed that water-soluble
silicone modified resin compositions could be prepared by reacting the
polyols, polybasic acids and alkoxy or hydroxy containing organosilicon
compounds together simultaneously. The procedure found in the Shin-Etsu
patent is a novel departure from the standard techniques used in the
silicone modified alkyd processing art discussed above; the novelty
residing in the fact that heretofore it was believed that co-reacting all
of the ingredients of a silicone modified alkyd simultaneously would
result in a gelled product.
The inventors herein have discovered that by utilizing certain silane
monomers in a certain process they can produce silicone modified alkyd
resins which have excellent properties when cured.
Thus one aspect of the invention herein is a process for producing a resin
which comprises contacting and reacting essentially simultaneously (A) an
aliphatic polyhydric alcohol or a mixture of aliphatic polyhydric
alcohols; (B) a polybasic carboxylic acid or an anhydride or mixtures
thereof; (C) an organosilane or a mixture of organosilanes having the
general formula R.sub.n Si(OR').sub.4-n wherein R is selected from a group
consisting of phenyl, methyl, ethyl, propyl and butyl radicals; R' is an
alkyl radical of 1-4 carbon atoms and n has a value of 1 or 2 and, (D) at
least a stoichiometric amount of water based on the amount of --(OR')
present in the mixture, at a temperature greater than 25.degree. C. for a
period of time sufficient to produce a resin with an acid value of 10-150.
A further aspect of the invention disclosed herein are the resins prepared
by the above described inventive process.
Another aspect of the invention disclosed herein are water-reducible resin
compositions which have utility in paint formulations which resin
compositions comprise (a) from 20 to 90 parts by weight of a resin which
is produced by contacting and reacting essentially simultaneously (i) an
aliphatic polyhydric alcohol or a mixture of aliphatic polyhydric
alcohols; (ii) a polybasic carboxylic acid or an anhydride or mixtures
thereof; (iii) an organosilane or a mixture of organosilanes having the
general formula R.sub.n Si(OR').sub.4-n wherein R is selected from a group
consisting of phenyl, methyl, ethyl, propyl and butyl radicals; R' is an
alkyl radical of 1-4 carbon atoms and n has a value of 1 or 2 and, (iv) at
least a stoichiometric amount of water based on the amount of --(OR')
present in the mixture, at a temperature greater than 25.degree. C. for a
period of time sufficient to produce a resin with an acid value of 10-150;
(b) 80-10 parts by weight of a water-miscible organic solvent selected
from a group consisting of aliphatic alcohols, glycols, monoalkyl ethers
of glycols and ketones; and (c) a basic compound selected from the group
consisting of trimethylamine, triethylamine, dipropylamine,
dimethylethanolamine, diethylethanolamine, triethanolamine and ammonia in
an amount sufficient to reduce the acid value of the composition to below
10.
Essentially, the starting materials which are used to prepare commercial
alkyds are those intended for use in this invention.
Thus, component (A) of the resin is an aliphatic polyhydric alcohol wherein
polyhydric means two, three, four or more carbinols per molecule of
alcohol. Occasionally, alcohols containing only one carbinol per molecule
can be used but only in small amounts, i.e. less than 5 weight percent,
and only when certain properties in the final resin are desired. Preferred
for this invention are such alcohols as pentaerythritol,
trimethylolethane, trimethylolpropane, 2,3-dimethyl-1,3-propane diol,
ethyleneglycol, propyleneglycol, trimethyleneglycol, glycerin,
1,4-cyclohexanediol, tetramethyleneglycol, 1,4-cyclohexanedimethanol,
hexamethylenediol, 2-methyl-2-ethyl-1,3-propanediol,
2,2,7,7-tetramethyl-1,8-octamethylenediol, 1,2,6-hexanetriol, sorbitol,
diglycerine and tris(2-hydroxyethyl)isocyanurate.
Especially preferred for this invention are 1,4-cyclohexanedimethanol,
trimethylpentanediol, trimethylolpropane, pentaerythritol and glycerine.
Component (B) of this invention is any dicarboxylic acid or anhydride or
mixtures thereof which are commercially used for alkyds. Preferred for
this invention are such dicarboxylic acids or their anhydrides as phthalic
acid, phthalic anhydride, terephthalic acid, isophthalic acid,
2,6-naphthalenedicarboxylic acid, succinic acid, glutaric acid, adipic
acid, sebacic acid, tetrahydrophthalic acid, tetrahydrophthalic anhydride,
trimellitic anhydride, hexahydrophthalic anhydride,
##STR1##
where x is an integer of 1 to 10.
Especially preferred for this invention are isophthalic acid and
trimellitic anhydride. It should be understood that the resins of this
invention can be modified with drying oil fatty acids. Drying oil fatty
acids can be any drying oil fatty acid that is commercially used in oil
modified alkyds. Preferred for this invention are fatty acids such as tall
oil fatty acid, soybean oil fatty acid, castor oil fatty acid, dehydrated
castor oil fatty acid, coconut oil fatty acid, linseed oil fatty acid,
tung oil fatty acid, fish oil fatty acid, olive oil fatty acid and cotton
seed oil fatty acid.
Especially preferred for this invention is dehydrated castor oil fatty
acid.
Component (C) of this invention is an alkoxy silane or a mixture of
alkoxysilanes having the general formula
R.sub.n Si(OR').sub.4-n
wherein R is selected from a group consisting of phenyl, methyl, ethyl,
propyl and butyl radicals; R' is an alkyl radical having 1-4 carbon atoms
and a has a value of 1 or 2. These silanes are commercially available and
it is not believed that a method for their preparation is required herein.
Preferred for this invention are the methoxy and ethoxy silanes. Especially
preferred are the methoxy silanes wherein a is 1 or 2 and the R group is
elected from phenyl, methyl and propyl or mixtures thereof. Such silanes
are for example CH.sub.3 Si(OCH.sub.3).sub.3, (CH.sub.3).sub.2
Si(OCH.sub.3).sub.2, C.sub.6 H.sub.5 SI(OCH.sub.3).sub.3, (C.sub.6
H.sub.5).sub.2 Si(OCH.sub.3).sub.2, CH.sub.3 CH.sub.2 CH.sub.2
Si(OCH.sub.3).sub.3, (CH.sub.3 CH.sub.2 CH.sub.2).sub.2
Si(OCH.sub.3).sub.2, CH.sub.3 Si(OCH.sub.2 CH.sub.3).sub.3,
(CH.sub.3).sub.2 Si(OCH.sub.2 CH.sub.3).sub.2, C.sub.6 H.sub.5
Si(OCH.sub.2 CH.sub.3).sub.3, (C.sub.6 H.sub.5).sub.2 Si(OCH.sub.2
CH.sub.3).sub.2, (C.sub.6 H.sub.5)(CH.sub.3)Si(OCH.sub.3).sub.2, (C.sub.6
H.sub.5)(CH.sub.3)Si(OCH.sub.2 CH.sub.3).sub.2 and mixtures thereof.
Generally, the components are present in certain amounts such that the
ultimate properties of the silicone modified alkyd resin both as an
uncured and as a cured material are variable.
The amount of component (A) used in this invention is dependent on the
amount of (B) that is used and also the type of material that component
(B) is required to be. The amount of component (C) that is required
depends on the final properties desired in the resin. Generally, enough
component (C) is used such that the final resin contains 10-80 percent by
weight of silicone. Preferably, the final resin contains 30-50 weight
percent of silicone. For purposes of this invention, 90-20 percent by
weight of the total amount of component (A) and component (B) are reacted
with the silicone. Preferred is 70-50 percent by weight. As mentioned
above, drying oil fatty acids can be used in this invention. Also, small
amounts of monobasic carboxylic acids can also be used herein.
As mentioned above, component (C) is preferably a mixture of silanes.
Mixtures of silanes allow one to tailor the properties of the final resin.
Mixtures of silanes, for example, can be C.sub.6 H.sub.5 Si(OR').sub.3 and
CH.sub.3 (CH.sub.2).sub.2 Si(OR').sub.3 ; C.sub.6 H.sub.5 Si(OR').sub.3
and (C.sub.6 H.sub.5).sub.2 Si(OR').sub.2 ; C.sub.6 H.sub.5
(CH.sub.3)Si(OR').sub.2 and CH.sub.3 Si(OR').sub.3 and, C.sub.6 H.sub.5
Si(OR').sub.3 and CH.sub.3 Si(OR').sub.3. Thus, there does not appear to
be any combination that cannot be made within the ambit of the groups
described for the above formula. Thus, any combination of substituted
groups in any ratio can be used in this invention as long as the average
degree of substitution on the silicon atoms by organic groups is at or
near 1.0. Desirable materials have a degree of substitution as close to
1.0 as possible because the cure of the final resin is enhanced.
Conversely, the closer one formulates to resins having a degree of
substitution less than 1.0, the more tendency the resin has to gel.
The resins can be prepared with or without organic solvents. Preferred
organic solvents are xylene and toluene. When the resin is desired to be
essentially solvent-free, then one only need to add a small amount of
solvent at the beginning of the reaction in order to azeotropically remove
by-produced water and then the small amount of organic solvent can be
strip-distilled at the end of the reaction. Because such small amounts of
organic solvent are required, their removal from the reaction mass is
relatively simple and easy.
Component (D) of this invention is critical in order to enable one to
prepare the compositions of this invention. The presence of component (D)
allows for the hydrolysis of the component (C) during the early stages of
the reaction and thus contributes towards the narrow dispersity of the
molecular weight of the resulting resin. Reactions carried out where the
components are all mixed together from the start but which do not contain
component (D) at the levels specified herein result in a wider dispersity
of molecular weights. The narrow dispersity of molecular weights enhances
the properties of the resins produced by the inventive process.
Occasionally, it may be preferable to prepare the silicone alkyd resin and
treat the resin with a carboxylic acid or acid anhydride in order to
introduce carboxylic acid groups into the final resin or to enable the
incorporation of higher mole percentages of CH.sub.3 SiO.sub.3/2 in the
presence of C.sub.6 H.sub.5 SiO.sub.3/2. This is done by merely adding the
acid or anhydride and cooking at azeotrope temperatures for a short period
of time.
The reaction to prepare the resins is carried out, generally at atmospheric
pressure, by combining all of the components and heating to a temperature
of about 90.degree. C. For purposes of this invention, it is generally not
desirable to heat the reaction mass at temperatures in excess of
250.degree. C. During the period time that the reaction is heated from
25.degree. C. to about 90.degree. C., the component (D) hydrolyzes the
alkoxysilanes and the condensation of the hydroxy groups thus formed
begins. When organic solvents are present, the temperature is regulated by
the azeotrope temperature of the organic solvent and the by-produced
water. Generally preferred is a temperature of 150.degree.-200.degree. C.
Occasionally, if the particular carboxylic acid or anhydride does not give
the reaction mass enough acidity to cause a rapid hydrolysis of the
alkoxysilanes, small amounts of mineral acids can be added, for example,
dilute aqueous hydrochloric acid.
The components are combined and the hydrolysis of the alkoxy groups on the
component (D) begins immediately and continues while the reaction mass is
being brought to reaction temperature. The alcohol produced by the
hydrolysis of the alkoxy silanes is generally the first product to distill
followed by the solvent-water azeotrope. The reaction mass is heated,
water produced by the condensation reaction is continually removed by the
azeotrope and the heating is continued until an acid value of 10 to 150 is
obtained. As indicated above, at this point additional carboxylic acids or
anhydrides can be added. Additional solvents can be added at this point if
desired. Upon cooling, the resins are viscous but pourable and are usually
clear water white or slightly clear yellow in color.
The resins at this point are ready to use. For water reducible systems, the
resins are usually dissolved in water and a water soluble or water
miscible solvent and then treated with basic compounds such as amines or
ammonia to neutralize the acids present and make the resin more water
soluble. Such compounds suitable for this invention are ammonia and those
amines such as trimethylamine, triethylamine, tripropylamine,
dipropylamine, dimethylethanolamine, diethylethanolamine and
triethanolamine.
Water-miscible or water soluble organic solvents useful in this invention
include aliphatic alcohols, glycols, monoalkyl ethers of glycols and
ketones. Specific examples of such solvents are methanol, ethanol and
propanol, ethylene glycol, propylene glycol and diethyleneglycol,
ethyleneglycol monomethyl ether, tetrahydrofuran, acetone,
methylethylketone and dimethylacetamide. Such solvents can be mixed.
For purposes of this invention, the water reducible resin is present in the
inventive composition at 20 to 90 parts by weight. The water-miscible or
water soluble organic solvent is present in 80 to 10 parts by weight and
the amount of basic compound present is dependent on the amount of acid in
the resin. Thus, enough basic compound must be added to the composition to
essentially reduce the acid value below 10. Water is then added to adjust
to the proper solids content.
The resin, solvent, water and basic compound are simply blended together.
The compositions are then ready for use. The compositions can be treated
with those adjuvants normally used in paint manufacture or they can be
used as clear coatings.
The following examples serve to illustrate the invention and should not be
construed as limiting the scope of the invention.
Acid numbers herein are titrated acid numbers using dilute standardized KOH
as the titrant and phenophthalein as the indicator.
Weight loss and percent non-volatile material determinations were carried
out by weighing known quantities of the polymers in aluminum moisture cups
and heating for 3 hours at 135.degree. C. and determining the difference
in the weight of the cup and resin before and after the heat treatment.
The viscosities of the resins are reported in Pascal Seconds (Pa.s) by
mathematical conversion of centipoise derived from a Brookfield viscometer
reading.
Paints made from the modified resins were evaluated for T-bend flex, T-bend
adhesion, 20.degree. and 60.degree. gloss, hardness, tack-free time, tape
test and water-spotting. These properties were compared against prior art
resins.
T-bend Flex and Adhesion
An aluminum panel is coated, cured and is bent over itself, using the panel
thickness as the mandrel diameter. The number of panel thicknesses the
panel has been bent over itself is the number of T-bends. The first bend,
in which the panel is simply bent 180.degree. C., is called OT, and the
bend becomes less severe as more thicknesses intervene, to form 1T, 2T
(two thicknesses), etc. The point at which there are no cracks when the
bent resin is viewed under a magnification of 7.times., is considered the
passing point and this is the T-bend number which is recorded.
The T-bend adhesion is tested at each bend by applying cellophane tape to
the bend and removing it quickly. If no paint is apparent on the tape,
this is the point which is considered passing.
Hardness
The method used in this study for determining hardness was pencil hardness.
Pencil leads varying in hardness, (4B, 3B, 2B, B, HB, F, H, 2H, 3H) were
shaped into a perfect cylinder and were pressed to the surface of the
paint, on aluminum, at a 45.degree. angle and moved with a continuous
forward motion (away from the operator). The pencil that will not cut into
or gouge the film, is the passing hardness for that film.
Tape Test
A piece of masking tape is put onto the film after the film has dried for 6
hours on an aluminum panel. A 50 gm weight is rolled over the tape and the
tape is left on for 1/2 hour. The tape is then removed and the film is
rated according to the degree of marring which is caused by the tape.
Water Spotting
After the film on an aluminum panel has air-dried for 6 hrs. and another
has dried for 24 hours, a drop of water is placed on each. The water is
allowed to evaporate and the films are then rated by determining the
amount of spotting caused by the water. The rating starts at "excellent"
for no mark at all to "poor" for an indentation in the film.
Tack Free time
The tack free time is the cure time needed for the coating to reach the
point where it releases from the finger when pressure is applied. This is
done by periodically placing a finger on the coating, applying pressure
and lifting the finger. At the point that the panel falls from the finger,
it is tack-free.
Gloss
Gloss is measured by a Gardner Glossometer.RTM.. This is a measure of
specular reflectance and is recorded for both 20.degree. and 60.degree.
incident angles. The glossometer is calibrated, placed on the coated
surface and % reflectance is read directly from a voltmeter connected to a
photocell.
Weather-o-meter
All samples were weathered in the Atlas Dew Cycle Weather-o-meter.RTM. for
1000 hours.
Revere Impact was carried out according to ASTM 2794-69-1974 "Resistance of
Organic Coatings to the Effects of Rapid Deformation".
In the examples, the following abbreviations were used.
______________________________________
CHDM 1,4-cyclohexanedimethanol
TMPD trimethylpentanediol
TMP trimethylolpropane
PE pentaerythritol
GLY glycerine
IPA isophthalic acid
TMA trimellitic anhydride
COFA dehydrated castor oil fatty acid
NPG neopentylglycol
AD adipic acid
______________________________________
EXAMPLE 1
Preparation of a silicone modified alkyd from silanes.
A 2-liter, 3-necked, round-bottomed glass flask was equipped with an
air-driven motor stirrer, thermometer, nitrogen sparge tube, viscosity cup
and a cold water cooled glass condenser which surmounted a Dean-Stark type
water trap for removing by-produced water. Under a nitrogen blanket this
apparatus was charged with 85 gms of pentaerythritol, 15.5 gms of
glycerol, 30 gms of soya fatty acid, 255.5 gms of C.sub.6 H.sub.5
Si(OCH.sub.3).sub.3, 74.8 gms of CH.sub.3 Si(OCH.sub.3).sub.3, 46.25 gms
of distilled water and 44 gms of xylene. The silane blend was calculated
to yield 203.5 gms of a 70/30 mole% C.sub.6 H.sub.5 /CH.sub.3 modification
at 30 weight percent silicone. The pot contents were heated to 100.degree.
C. while removing methanol. Thereafter, 111 gms of phthalic anhydride were
added and the pot contents were heated at 210.degree.-230.degree. C. at
xylene reflux while removing a total of 166.6 gms of methanol and 48 gms
of water, methanol and xylene. The viscosity was monitored and the heating
was carried out until a 13.0 second viscosity and an acid value of 24 was
reached. The material was then cooled and xylene was added to give a 60%
solids solution of clear, reddish-brown colored resin having a viscosity
of 2180 centipoise (2.18 Pa.s) at 60% solids.
EXAMPLE 2
A reaction analogous to Example 1 was carried out wherein C.sub.6 H.sub.5
Si(OCH.sub.3).sub.3 and CH.sub.3 CH.sub.2 CH.sub.2 Si(OCH.sub.3).sub.3
were used in a 70/30 mole percent ratio to give an acid value of 13 and a
viscosity of 1559 centipoise (1.559 Pa.s) at 57% solids resin.
EXAMPLE 3
A further run was made analogous to Example 1 except the silanes C.sub.6
H.sub.5 Si(OCH.sub.3).sub.3 and CH.sub.3 Si(OCH.sub.3).sub.3 in a mole
ratio of 50/50 were used to yield a resin having an acid value of 55 and a
viscosity of 3600 centipoise (3.6 Pa.s) at 60% solids resin.
EXAMPLE 4
A prior art silicone modified alkyd resin was prepared by reacting a
hydroxy-containing, low molecular weight siloxane sold as Z6018 by the Dow
Corning Corporation, Midland, Mich., United States, in the following
manner: 140 parts of 1,4-cyclohexanedimethanol, 53 parts of
trimethylolpropane, 66 parts of isophthalic acid, 220 parts of the
siloxane and 218 parts of dehydrated castor oil fatty acid were charged
into an apparatus similar to that described in Example 1 above. This
material was heated to 190.degree. C. very rapidly and then to 240.degree.
C. The reaction mass was held at that temperature until an acid value of
12 was reached. The material was cooled to 170.degree. C. and 66 parts of
trimellitic anhydride was added and the temperature was held at
170.degree. C. to 180.degree. C. until an acid number of 50 was reached.
When cooled, the resin was diluted with solvent to 60 percent solids. It
was clear and colorless. This material was then compared to Examples 1, 2
and 3, of this invention, on the Gel Permeation Chromatograph (GPC). The
solutions were run on a Waters 200 model, chromatograph, manufactured by
Waters Co., Framingham, Mass. The graph speed was 0.1 in/min and the
attenuation was 4x. The columns were polystyrene filled. Examples 1 and 4
were run at 1/2 weight percent in methylene chloride. Example 2 and 3 were
run at 1/4 weight percent in methylene chloride.
In comparing the inventive resins in Examples 1, 2 and 3 to the prior art
resin, Example 4, reference should be made to FIGS. 1-4. The figure
numbers correspond to the example numbers and it should be noted that the
figures all have the exact same basis which is elution time in minutes on
the Waters chromatograph column. Each figure shows the entire amount of
elutable material injected so that all elutable material can be compared.
The position of the median peaks are immaterial for this comparison. The
comparison to be made is the narrow molecular weight dispersions of the
materials shown in Examples 1, 2 and 3 (i.e. 5-70 min.) to the very broad
molecular weight dispersion of Example 4 (i.e. 5-120 min.).
EXAMPLE 5
Comparison of prior art resins.
A composition was prepared by the process set forth in Example 1 of U.S.
Pat. No. 4,035,332. This material was designated Sample A.
A second composition was prepared according to the instant invention
wherein the ingredients were used which would give the same silicone to
organic ratio as Sample A and wherein the organic substitution on the
silicone was the same as in Sample A. This material was designated Sample
B. Table I shows the formulations.
TABLE I
__________________________________________________________________________
Formulation of silicone alkyd resins for comparison purposes
mole ratio of
gms gms
gms gms gms C.sub.6 H.sub.5 SiO.sub.3/2 to
Ref
NPG AD TMA xylene
H.sub.2 O
silicone C.sub.6 H.sub.5 (CH.sub.3)SiO.sub.1/2
Acid #
__________________________________________________________________________
A 78 36.5
48 81.25
0
##STR2## 25/75 36
B 78 36.5
48 81.0
14.5
C.sub.6 H.sub.5 Si(OCH).sub.3
25/75 38
C.sub.6 H.sub.5 (CH.sub.3)Si(OCH.sub.3).sub.2
__________________________________________________________________________
All of the materials of Sample B were mixed together and heated at
91.degree. C. for 4 hours while azeotroping by-produced water. It was then
heated over a period of 4 hours from 100.degree. C. to about 140.degree.
C. whereupon 30 gms of xylene was a | | |
