Mixtures comprising epoxide compounds and their use

Details Mixtures comprising epoxide compounds and their use Mixtures comprising epoxide compounds and their use

2001-11-29

2003-05-20

Dawson, Robert (Department: 1712)

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

Synthetic resins

Processes of preparing a desired or intentional composition...

C428S413000, C523S466000, C525S472000, C525S523000, C528S106000

Reexamination Certificate

active

06566423

ABSTRACT:

STATE OF THE ART
Due to their high mechanical strengths and good chemical stability, epoxy resins are often used as binding agents in coating materials. In the case of corresponding cold-curing systems, amine curing is preferred, particularly curing with amine-terminal addition products of epoxide compounds and amines. Apart from diverse solvents, such as benzyl alcohol, these addition product curing agents comprise additionally modification means and accelerators depending on the applications.
While the surfaces of correspondingly cured mixtures are continuous and smooth, they do not, in every respect, meet all the requirements for a decorative surface. Due to the production, the addition products comprise free monomeric amines which, during the curing process, migrate to the surface and there separate out and cause faults. Furthermore, the amines, which migrated to the surface, can react with moisture and carbon dioxide of the ambient air with the formation of carbamates and carbonates, which also impair the optical and tactile quality of the surface. In addition, the free amines are skin irritants or are caustic.
OBJECTS OF THE INVENTION
It is an object of the invention to provide cold-curing mixtures comprising epoxide compounds and curing agents, which mixtures, after curing, exhibit good chemical stability and high mechanical strength characteristic of epoxide resins, which are not irritating to the skin and are free of solvents, but whose viscosity is so low that they can be readily processed at ambient temperatures and which are self-levelling and, in the cured state, have an optically and tactilely faultless surface.
It is another object of the invention to provide novel objects prepared from the said mixtures having superior properties.
These and other objects and advantages of the invention will become obvious from the following detailed description.
THE INVENTION
The novel mixtures of the invention are comprised of
a) 5-50 wt. % of epoxy resin with at least two epoxide groups per molecule,
b) 1-25 wt. % of reactive thinner comprising epoxide groups,
c) 1-25 wt. % of epoxy-amine addition product with terminal amino groups,
d) 1-20 wt. % of modification means,
e) 0-80 wt. % of filler materials and additives, wherein the epoxy-amine addition product is an isolated addition product of one mole of amine and one to two equivalents of at least one epoxide compounds having up to two epoxide groups per molecule, and that the modification means is a xylene-formaldehyde resin or a mixture of xylene-formaldehyde resin with up to 60 wt. % of another modification means.
These mixtures are preferably used for the production of decorative surfaces, in particular of decorative floor coatings, of coatings in bathrooms and sanitary blocks and for the hand lay-up lamination of formed parts and for the production of composite materials with surfaces which have optically and tactilely aesthetic properties as well as with decorative surfaces, produced from the said mixtures.
A substantial improvement in the surface quality of epoxy resins cured with amine-terminal epoxy-amine addition products is attained if, as the epoxy-amine addition products, isolated addition products of one mole of amine with 1 to 2 equivalents of an epoxide compound with up to two epoxide groups per molecule are used. Such addition products are nearly odor-free and are not irritating to the skin and they are considerably more compatible with epoxide compounds than monomeric amines. Therefore, they do not migrate to the surface of a corresponding mixture and thus do not lead to faults through sequestration, efflorescence or formation of carbamates. While the cured products are slightly colored, they are colorfast, i.e. further yellowing hardly occurs.
Such isolated amine-terminal addition products of one mole of amine and one to two equivalents of at least one epoxide compound, in the following denoted only as “isolated addition products”, are known from an earlier application by the applicant (german File Number 100 13 735.0). They are produced in the conversion known per se of distillable mono-, di- and/or polyamines with epoxide compounds, wherein the amines are used in at least a 10% molar excess relative to the epoxide groups of the epoxide compounds, and the subsequent separation of the excess amines by distillation. For chemical reasons, the excess of amines can be unlimited, but since the excess amines must again be distilled off, it is advisable to limit the excess for reasons of economy. In general, the amines are therefore employed at a 10 to 100% molar excess relative to the epoxide groups of the epoxide compounds. This makes possible that only amine-terminal addition products are obtained.
Examples of suitable amines which can be employed are primary monoamines, such as butylamine, cyclohexylamine, aniline or benzylamine, as well as aliphatic, araliphatic, cycloaliphatic, aromatic mono- or di- and/or polyamines, provided they can be distilled without undergoing decomposition, and provided they contain at least one primary amino group or, when using secondary amines, at least two secondary amino groups to enure that the desired addition product has at least one free primary or secondary amino group per molecule.
Aliphatic di- and/or polyamines are preferably used and examples are ethylene-diamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, trimethylhexanediamines, methylpentanediamines, pentaethylenehexamine, 1,2-diaminopropane, 1,3-diaminopropane, 1,2-, 1,3- and 1,4-diaminobutane, 3-(2-aminoethyl)aminopropyl amine, N,N′-bis(3-aminopropyl)ethylene diamine, 1,2-diaminocyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, N-aminoethyl piperazine, N-aminopropyl piperazine, N-aminobutyl piperazine, phenylene diamines, xylene diamines and isophorone diamine or mixtures of these amines.
Examples of the epoxide components that can be employed are all compounds individually or mixed with one another, which are gaseous or liquid at ambient temperature and which contain at least one oxirane group in the molecule.
Since the addition products are employed in solvent-free mixtures which can be processed at ambient temperature and which are self-levelling, such addition products are preferred which have a viscosity as low as feasible. Therefore, the epoxide components are also preferred low-molecular aliphatic, araliphatic, cycloaliphatic, aromatic or heteroaromatics-containing compounds which contain up to two oxirane groups. Examples of these are butyl-, hexyl-, phenyl-, butylphenyl-, nonylphenol-, cresylglycidyl ethers, resorcinol diglycidyl ether, C
2
-C
20
carboxylic acid glycidyl esters and ethylene-propylene- or butylene oxide.
Preparation of the addition products takes place by conversion of the reaction partners (optionally under pressure) at temperatures in the range of 20 to 140° C., preferably in the range of 50 to 90° C., and maintaining the reaction mixture for approximately 1 to 5 hours at temperatures in this range. Subsequently, preferably under vacuum, the separation by distillation takes place of the amines that have not been converted.
The amounts of the addition product used in the mixtures of the invention must be such that the amine hydrogen atoms introduced therewith—provided the mixture does not contain further epoxide resin curing agents—are equimolor to the sum of the epoxide groups of the resins and reactive thinners employed. In general, they are in the range of 1 to 25 wt. % relative to the total mixture.
The xylene-formaldehyde resins employed as modification means are low-molecular and low-viscosity, but not volatile products, produced by acid-catalyzed condensation of xylene and formaldehyde. They are known inter alia from Ullmann's Encyklopädie der technischen Chemie, 4th Edition, Vol. 12, p. 542 or Houben-Weyl, Methoden der organischen Chemie, Vol. E 20/Part 3, pp. 1796 to 1798 and are commercially available. It is also known to use these resins as extenders for mixtures of epoxy resin and curing agents, especially to reduce the viscosity o

Affiliated with

Also associated with

Rating

Mixtures comprising epoxide compounds and their use does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Mixtures comprising epoxide compounds and their use, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Mixtures comprising epoxide compounds and their use will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3031309