Diglycidylester of alkylated hexahydrophthalic anhydride

Details Diglycidylester of alkylated hexahydrophthalic anhydride Diglycidylester of alkylated hexahydrophthalic anhydride

1998-05-20

2001-07-24

Sellers, Robert E. L. (Department: 1712)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

From carboxylic acid or derivative thereof

C525S423000, C525S438000, C525S510000, C525S528000, C525S533000, C549S515000

Reexamination Certificate

active

06265531

ABSTRACT:

The invention relates to a glycidylester and to a thermosetting resin composition comprising the glycidylester.
Resins based on &agr;,&agr;-branched dicarboxylic acids are known such as EP-A-0518408.
It has been demonstrated that coatings based on &agr;,&agr;-branched dicarboxylic acids (such as diethyl malonic acid) exhibit a good outdoor durability. Such &agr;,&agr;-branched dicarboxylic acids have been incorporated into binder resins via a sequence of reactions. Firstly, the acids were glycidated to form the corresponding diglycidylesters. Subsequently, a linear polyester was prepared via an advancement (i.e. fusion) reaction of an &agr;,&agr;-branched diacid with the corresponding diglycidylester. The hydroxyl groups of the resulting polyesters were used for the cross-linking reaction with a melamine resin.
However, according to the important paint manufacturers, the resistance towards acids (acidic rain) of these coatings is insufficient.
For this reason we have taken a new approach in the synthesis of an inexpensive feedstock for acid resistant coatings with acceptable UV resistance. We have found that &agr;,&bgr;-substituted dicarboxylic acids are suitable base materials for outdoor durable coatings, having excellent resistance against acid rain.
Therefore the invention relates to a glycidylester of the general formula I
in which
R
1
and R
4
are the same or different C
1
-C
6
alkyl or C
6
-C
10
cycloalkyl groups, and R
2
and R
3
are the same or different and are H or C
1
-C
6
alkyl or C
6
-C
10
cycloalkyl groups.
Such structures can be prepared via a Diels-Alder reaction of maleic anhydride and a diene.
Allo-ocimene ((4E,6E)-2,6-dimethyl-2,4,6-octatriene) is a suitable starting compound. In this compound, the groups R
1
and R
4
(which are the &bgr;-substituents in the final product) are an isobutenyl- and a methyl group.
In fact, allo-ocimene is the best, thus preferred compound that comes in perspective for our objective.
The reaction of allo-ocimene and maleic anhydride gives compound (1). After hydrogenation, compound (2) is obtained that serves as a feedstock for acid resistant coatings.
The Diels-Alder reaction is in fact an addition reaction, it has a 100% atom utilisation, and produces no waste materials. The same is true for the hydrogenation and hydrolysis steps. There are, in theory two ways in which allo-ocimene and maleic anhydride can form a Diels-Alder adduct. This is because allo-ocimene has two butadiene fragments. Thus, two adducts are possible, compounds (1) and X. However, due to steric hindrance isomer X cannot form. Therefore, the reaction gives only one isomer (1); see Figure. I.
The Diels-Alder reaction of allo-ocimene and maleic anhydride is reported in the literature.
See:
E. K. von Gustorf, J. Letich; Tetrahedron letters 45, 4689, (1968)
L. A. Goldblatt, S. Palkin; J. Am. Chem. Soc. 63, 3517, 3520 (1941)
Y. Chrétien-Bressiere; Annales de Chemie 13, 301, 331, (1957)
A. R. Vil'chinskaya, B. A. Arbuzov; J. Gen. Chem. USSR, 29, 2686, (1959)
J. E. Milks, J. E. Lancaster; J. Org. Chem., 30, 888, 890, (1965)
K. T. Joseph, G. S. Krishna Rao, Tetrahedron, 23, 519, (1967)
B. A. Arbuzov, Chemische Berichte 1968 (1934)
In these cases, the reagents are mixed without solvent or catalyst. Immediately after adding the solid maleic anhydride to the allo-ocimene, the liquid turns intensely orange. At room temperature no reaction takes place, since the maleic anhydride poorly dissolves in allo-ocimene. When the mixture is carefully heated to approximately 50° C., the reaction starts. The Diels-Alder reaction is very exothermic, the temperature reaches 170-190° C. within several minutes. During the course of the reaction, the orange/yellow color weakens. After 15 minutes the temperature starts to drop and after about 45 minutes the mixture solidifies as pale yellow crystals. The yield is almost quantitative. Adding the components in a different sequence (allo-ocimene to maleic anhydride) has no effect on the color, nor has purification of the allo-ocimene by distillation. We have found that the Diels-Alder reaction of allo-ocimene and maleic anhydride proceeds in very high yield (over 97%). Due to secondary orbital interactions in the transition state, we expected to form the isomer in which the methyl- and isobutenyl moiety are directed cis with respect to the anhydride moiety (compound 1). Literature data also predict this conformation.
The yellow anhydride (1) is hydrogenated, preferably in ethyl acetate using PtO
2
as a catalyst (Adams catalyst). The hydrogenation is advantageously carried out in an autoclave with magnetic stirring, using 30 bars of hydrogen. In approximately 2-3 hours, the consumption of hydrogen gas stops. The hydrogenated product, 2,3-dimethyl-5-isobutyl-hexahydrophthalic anhydride (2), is a slightly yellow colored, low-viscous oil.
The glycidation of the hydrogenated product (2) is preferably performed using per mole of anhydride an excess of 10 mole of epichlorohydrine (ECH). 9 Mole of isopropanol are added as co-solvent. The crude resin is advantageously submitted to a mild after dehydrochlorination treatment. This is suitably performed with a 30% solution of the resin in methylisobutylketon (MIBK) at 40° C. for 1 hour.
The yield of the glycidation reaction is extremely good, 97%. Some losses due to hydrolysis occur in the ADHC treatment, but the overall yield is still 87%.
The coatings based on this glycidylester show a combination of sufficient UV stability and high acid resistance.
The invention further relates to a thermosetting resin composition comprising
i) a glycidylester of the general formula I
in which
R
1
and R
4
are independently C
1
-C
6
alkyl or C
6
-C
10
cycloalkyl groups, and R
2
and R
3
are independently H or C
1
-C
6
alkyl or C
6
-C
10
cycloalkyl groups, and
ii) a curing compound selected from the group of amino resins blocked or unblocked (cyclo)aliphatic isocyanates, alpha,alpha′-dibranched cyclic anhydrides, acid-functional polyesters containing only alpha,alpha′-dibranched acid and ester groups, (cyclo)aliphatic amines, (cyclo)aliphatic polyamino amides, blocked or unblocked Lewis acids, and tertiary amines.
Preferably R
1
and R
2
are methylgroups, R
3
is hydrogen, and R
4
is an iso-butylgroup.
The novel epoxy resin is a low viscous, slightly yellow colored oil. Coatings based on this epoxy resin proved to be more resistant towards acids than coatings based on the diglycidylester of &agr;,&agr;-branched diethylmalonic acid.
In order to improve the present resin it is preferably reacted with a dicarboxylic acid to form a hydroxyl rich polyester.
This is called an advancement or fusion reaction. The obtained linear polymer is then cured via the hydroxyl groups using a curing agent.
Therefore the invention preferably relates to a thermosetting resin composition comprising
i) an advanced resin product obtainable by reacting
a) a diglycidylester of the general formula I
in which
R
1
and R
4
are the same or different C
1
-C
6
alkyl or C
6
-C
10
cycloalkyl groups, and R
2
and R
3
are the same or different and are H or C
1
-C
6
alkyl or C
6
-C
10
cycloalkyl groups, with
b) an alpha,alpha′-dibranched dicarboxylic acid of the general formula II
wherein n is 0 or 1,
wherein R is independently selected from the group consisting of straight and branched chain alkyl, cycloalkyl, arylalkyl and aryl, or both R's may form part of a substituted or unsubstituted cycloaliphatic ring system comprising 5, 6 or 8 carbon atoms, in which case n should be 0, and/or
c) an &agr;,&bgr;-dibranched dicarboxylic acid
R
1
, R
2
, R
3
and R
4
being as broadly defined hereinbefore,
ii) a curing compound selected from the group consisting of amino resins blocked or unblocked (cyclo)aliphatic isocyanates, alpha,alpha′-dibranched cyclic anhydrides, acid-functional polyesters containing only alpha,alpha′-dibranched acid and ester groups, (cyclo)aliphatic amines, (cyclo)aliphatic polyamino amides, blocked or unblocked Lewis acids, and tertiary amines.
Advantageously R
1
an

Affiliated with

Also associated with

Rating

Diglycidylester of alkylated hexahydrophthalic anhydride does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Diglycidylester of alkylated hexahydrophthalic anhydride, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Diglycidylester of alkylated hexahydrophthalic anhydride will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2516265