Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
2002-01-18
2004-01-06
Sellers, II, Robert E. (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C523S404000, C528S103000
Reexamination Certificate
active
06673877
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to aqueous binders for corrosion protection systems which are oxidatively crosslinkable by atmospheric oxygen via their olefinic double bonds.
BACKGROUND OF THE INVENTION
Air drying resins or binders are known primarily in the field of alkyd resins; water dilutable alkyd resins are obtained by mixing (unmodified) alkyd resins with emulsifiers or by incorporation of a sufficient number of acid groups, which remain following the condensation reaction, and the neutralization of at least some of said groups, or cocondensation with hydrophilic polyoxy-alkylene polyols such as polyethylene glycol.
By way of example, hydroxy functional emulsifiers for alkyd resins based on polyurethane polyureas are known from EP-A 0 741 156. Other externally emulsified aqueous alkyd resin compositions are described in EP-A 0 593 487. Alkyd resins with chemically incorporated emulsifier (self-emulsifying) are known from EP-A 0 312 733.
Water compatibility is achieved in all cases by the use of nonionic or anionic emulsifiers, in chemically incorporated or added form.
It is also known to modify polyurethane resins by incorporating unsaturated fatty acids (EP-A 0 444 454) so that paints produced with them are air drying.
Epoxy functional resins which through modification with fatty acids lead to air drying binders are described in EP-A 0 355 761 (esters of fatty acids with epoxy resins), 0 316 732, 0 370 299 (acrylate resins with epoxide groups), and 0 267 562 (alkyd, urethane-alkyd or epoxide-ester resins grafted in an aqueous medium with olefinically unsaturated monomers).
Aqueous formulations of neutralized reaction products of epoxy resin-amine adducts and fatty acids are known from EP-A 0 070 704. There, amines and epoxy resins based on polyhydric phenols are used to prepare adducts having a molar mass of from 1000 to 3000 g/mol which are then reacted with unsaturated fatty acids to give a product in which the mass fraction of these fatty acids is from 25 to 50%. The amount of fatty acids is to be chosen so that all of the active amine hydrogen atoms are consumed.
AT-B 390 261 discloses emulsions of epoxy resin esters which can be used as binders for air drying paints. The resins are prepared by reacting epoxy resins, partially esterified with fatty acids, and copolymers of unsaturated fatty acids and (meth)acrylic acid, and further copolymerizable monomers, and to achieve water dilutability are at least partly neutralized using alkalis. These resins may also be admixed with amino functional epoxy resin esters.
SUMMARY OF THE INVENTION
It has now been found that reaction products of epoxy resins and fatty acid modified epoxide-amine adducts may be used as binders for air drying paints which afford excellent corrosion protection to metallic substrates.
The invention accordingly provides products A′ABC of reaction of epoxy resins, fatty acids, and amines, which are reaction products of epoxide compounds A′ containing at least two epoxide groups per molecule and reaction products ABC of epoxide compounds A, fatty acids B, and amines C, and wherein their number average molar mass M
n
is at least 5000 g/mol, and, where appropriate, the epoxide compounds A′ and/or the epoxide compounds A have been modified prior to further reaction, in whole or in part, by reaction with compounds D containing at least one acid group or hydroxyl group reactive toward epoxide groups, and, where appropriate, the amines C have been modified prior to further reaction, in whole or in part, by reaction with aliphatic or aromatic monoepoxide compounds A″ or mixtures thereof.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In particular, the molar mass calculated from the stoichiometry (number average molar mass), M
n
, of these reaction products A′A B C is preferably at least 10000 g/mol, more preferably at least 15000 g/mol, and with particular preference at least 20000 g/mol, and their (measured) acid number is not more than 5 mg/g. Following at least partial neutralization of the amino groups, the reaction products are dispersible in water and form stable dispersions which do not form any sediment even after 4 weeks of storage at room temperature (20° C.).
The epoxy resins A and A′ are selected independently of one another from diepoxide or polyepoxide compounds which are obtainable in a known manner by reacting epichlorohydrin with aromatic or (cyclo)aliphatic compounds containing two or more hydroxyl groups per molecule (Taffy process), or may be obtained by reacting diepoxides or polyepoxides with the aforementioned aromatic or (cyclo)aliphatic compounds containing two or more hydroxyl groups per molecule (advancement reaction). Preference is given to epoxy resins based on aromatic dihydroxy compounds, such as bisphenol A, bisphenol F, dihydroxydiphenyl sulfone, hydroquinone, resorcinol, 1,4-bis[2-(4-hydroxyphenyl)-2-propyl]benzene, or aliphatic dihydroxy compounds such as 1,6-hexanediol, 1,4-butanediol, cyclohexanedimethanol, or oligo- and poly-propylene glycol. The specific epoxide group content of the epoxy resins is preferably from 0.4 to 7 mol/kg, in particular from 0.6 to 6 mol/kg. In one preferred embodiment, diepoxide compounds are used in each case for A and A′, the specific epoxide group contents being from 0.5 to 4 mol/kg in the case of A and from 2 to 5.9 mol/kg in the case of A′.
Particular preference is given to epoxy resins based on bisphenol A and bisphenol F and mixtures thereof.
The fatty acids B contain at least one olefinic double bond and have from 6 to 30, preferably from 8 to 26, and in particular from 16 to 22 carbon atoms. Preference is given to palmoleic acid, oleic acid, and erucic acid; linoleic acid, linolenic acid, and eleostearic acid, arachidonic acid, and clupanodonic acid, and also the fatty acids obtainable as mixtures from the naturally occurring oils, such as linseed oil fatty acid, conjuvandol fatty acid, tall oil fatty acid, cottonseed oil fatty acid, rapeseed oil fatty acid, and the fatty acid mixtures obtained from dehydrated castor oil.
The amines C are preferably aliphatic, linear, cyclic or branched amines which contain at least one primary or secondary amino group. They have preferably from 2 to 12 carbon atoms and may also contain tertiary amino groups and/or hydroxyl groups as functional groups. Particularly suitable are primary monoamines having from 6 to 12 carbon atoms such as hexylamine, cyclohexylamine, 2-ethylhexylamine, and stearylamine, primary-tertiary diamines such as dimethylaminopropylamine, diethylaminopropylamine, diprimary-secondary amines such as diethylenetriamine, triethylenetetramine, and tetraethylenepentamine, and the mixtures of oligomeric diaminopolyethyleneimines available commercially as ®Polymin, and also secondary amines and diamines such as piperidine, piperazine, di-n-butylamine, morpholine, and hydroxy functional amines such as ethanolamine, diethanolamine, and diisopropanolamine. Mixtures of said amines may also be used.
It is possible to prepare the intermediates ABC by sequential reaction, in which case first the epoxide compounds A are reacted with the amines C and in a second step these adducts are reacted with the fatty acids B to give the intermediate A B C. It is, however, also possible first to react the epoxide compounds A with the fatty acids B and then to react the remaining epoxide groups with the amines C. It is likewise possible to perform the reaction simultaneously and so to obtain the intermediates ABC in one step. The amounts of the reactants A, B and C are chosen such that substantially all of the epoxide groups, i.e., at least 90%, preferably at least 95%, and in particular at least 98% of the epoxide groups originally present in A are reacted. Preferably, the reaction is also to be conducted such that the intermediate ABC no longer contains any reactive amine hydrogen atoms; at the most, however, the amount of amine hydrogen atoms may be 10 mmol/kg.
One variant of the present invention comprises, when using amines C con
Feola Roland
Friedl Maximilian
Gmoser Johann
Krassnitzer Manfred
Paar Willibald
ProPat L.L.C.
Sellers II Robert E.
Solutia Austria GmbH
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