CS200848B1 - Polyamine curing agent for curing of epoxy resins or co - Google Patents

Description

(54) Polyamine hardener for curing epoxy resins or compositions thereof

The present invention relates to a new type of polyamine hardener for curing epoxy resins or compositions of these resins with modifying agents and additives.

Epoxy resins based on Bisphenol A and other aromatic phenols or novolaks, due to the rigid aromatic structure of the backbones, have a fragile character, which is manifested not only in resins with a softening point above 50 ° C, but also in cured compositions, these materials modified. A number of possibilities are known from the literature to improve the mechanical properties of cured epoxides. This is most often solved by the addition of substances with a flexible structure which serve as external or internal plasticizers or plasticizing hardeners. However, these plasticizing compounds are often structurally different, incompletely miscible, susceptible to thermal or light degradation, and also disadvantageous in economic terms.

Significant changes in properties occur with relatively little interference in the structure of the cured composition by the addition of curing polyamines (French Patent Nos. 1,155,368, U.S. Patent Nos. 2,817,644 and 2,897,179, British Patent Nos. 781,412; A. Renner et al. : Chimia lg, (1965), No. 3, pp. 120-162; H. Jahn: Epoxidharze, Leipzig 1969, pp. 45-159, 162). Most of the polyamines used contain primary amine groups, so that after curing, the E - N - E structure forms in the mass

AND

R

200 848

200 848 wherein R is a polylylamine residue and E is an epoxy resin residue. Whether R already contains a long or short chain, the grouping of two epoxy residues just around the nitrogen atom represents a solid block, which may cause insufficient toughness of the cured mass. However, using a secondary amine as the hardener, the resulting element has a structure having only 1 epoxy chain on the amine nitrogen separated from the second epoxy chain on the other secondary amine nitrogen. When these two types of amine hardeners are applied with the same number of active hydrogen per mole of hardener,

- N - R '- N - E,

I I

E E in the second case

E n-r'-n-r'-nI

E E where R and E represent the above groups and R * is an alkylene chain (typically ethylene or propylene) between the individual amino groups of the polyamine, the second type being mechanically more resistant after curing, although the overall functionality and mesh density are approximately the same. However, its disadvantage is a significantly lower curing speed. Indeed, the secondary amine reacts by structure up to 8 times slower than a similar primary amine and, moreover, has a lower heat resistance.

In practice, the present invention is directed to a polyamine hardener for curing epoxy resins or compositions thereof with modifying agents and / or additives. The invention is characterized in that the hardener is a mixture consisting of 40 to 97 wt. % of aliphatic and / or cycloaliphatic polyamines containing both primary and secondary amino groups in the molecule, the primary amino group content being less than the ratio of one of these amino groups per 100 g of amine mass, and from 3 to 60 wt. % of secondary amines containing at least one secondary amino group per 30 g of amine mass. Such a hardener is preferably formed by a technical mixture which is formed by the hydrogenation of adducts of cycloaliphatic amines, in particular of cyclohexylamine, with acrylonitrile.

In addition to the main product N-cyclohexyl-1,3-propylenediamine, said mixture also contains 3 to 50 wt. % bis (N-cyclohexyl-3-aminopropyl) amine. N-methyl-1,3-ethylenediamine, N, N'-dimethyl-1,3-propylenediamine, N-cyclohexyl-1,3-propylenediamine, bis (4-amino-3-methylcyclohexyl) can also be used as amine. methane, bis (4-aminocyclohexyl) propane, bis (N-cyclohexyl-3-aminopropyl) amine, bis / 3- (1-morpholyl) propylamine and the like.

The hardeners of the present invention can be used to cure a variety of different types of epoxy resins, most commonly those resulting from the condensation reactions of epichlorohydrin, β-methylepichlorohydrin, or β-glycerinedichlorohydrin with polyphenols, e.g.

4,4'-dihydroxydiphenylmethane, 4,4'-dihydroxydiphenylpropane, resorcinol, hydroquinone, phenolic novolaks and the like, but also the phenylglycidyl ethers of aliphatic polyols, triglycine 20048 dylcyanurate, polyglycidyl esters of polycarboxylic acids and curing compositions, etc. can be cured on their own, as well as resins. containing modifying agents and / or additives such as accelerators, plasticizers, solvents, pigments, dyes, fillers, various macromolecules of the compound and optionally others. The hardener is used in a ratio of 1 to 50 g for every 100 g of epoxy resin.

The products cured by the polyamine hardener according to the invention have advantages over the products cured by the polyamine hardeners hitherto known and used in particular in that they have both excellent mechanical properties as well as good heat resistance and at the same time advantageous reaction rate for most processing fields. These properties have not yet been achieved with hardeners in this complex.

Examples:

Example 1

O

Weigh 400 g of a low-molecular-weight epoxy resin of the palm-type epoxy equivalent of 0.52 / 100 g, 131 g of N-cyclohexyl-1,3-propylenediamine containing 12% bis (N-cyclohexyl-5-aminopropyl) into a 1000 cm polyethylene container. The reaction product is mixed and cast into prepared molds. Cures for 12 hours at 20 ° C and cures for 2 hours / 100 ° C.

O

The product provides a bending strength of over 60 kJ / m with a maximum of 97 kJ, a bending strength of 108 MPa, a modulus of elasticity of 2637 MPa.

Example 2

The procedure of Example 1, except that 40 g of dibutyl phthalate and 100 g of porcelain flour were added. The composition is used as a sealant, which needs to be hardened at ca 100 ° C by means of an infrared lamp. It provides tough materials with good filling properties.

Example 3

Weigh 400 g of the low molecular weight epoxy resin used in Example 1, 40 g of butyl glycidyl ether and 37 g of bis (4-aminocyclohexyl) propane containing 15 wt. bis (N-cyclohexyl-3-aminopropyl) amine. This reaction mixture is impregnated with glass fiber, compressed at normal temperature and then cured at 100 ° C for 3 hours. The laminate has good mechanical properties and heat resistance.

Example 4

Weigh 400 g of low molecular weight dian-type epoxy resin with an epoxy equivalent of 0.52 / 100'g, 32.5 g of bis (4-amino-3-methylcyclohexyl) -methane and 3.6 g of bis (N-) into a 1000 cp polyethylene container. cyclohexyl-3-aminopropyl) amine. The reaction product is mixed and cast into molds. After curing at 12 hours / 20 ° C and 2 hours / 100 ° C, they provide bodies which have a 28% higher toughness and higher flexural strength compared to the same epoxy resin cured with bis (4-aminocyclohexyl) methane alone.

Example 5

The procedure is as in case 4, except that bis (4-amino-3-methylcyclohexyl) is substituted

200,840 methane add 27 g of bis (4-aminocyclohexyl) methane. The impact strength of bis (4-aminooyclohexylmethylene) alone is increased by 16%.

Example 6

Weigh 100 g of a low molecular weight resorcinin epoxy resin with an epoxy equivalent of 0.59 / 100 g, 4 g of diethylenetriamine, 5 g of N, N-dimethylpropylenediamine and 10 g of polyvinyl butyral into the polyethylene container and mix for 10 min. mixes el. mixer. The resulting composition can be used for bonding metal sheets for 24 hours at normal temperature and 4 hours at 100 ° C. The glued joints have excellent peel strength.

Example 7

100 g of epichlorohydrin-epian resin with a diane's softening point of 96 ° C and an epoxy equivalent of 0.096 / 100 g are ground in a hammer mill and mixed with 4 g of dicyandiamide and 2 g of solid, consisting of 1 g of aerosol and 1 g of aerosol. g of bis (N-cyclohexyl-3-aminopropyl) amine, and 50 g of TiO ₂ rutile type, 2 g of low molecular weight polybutyl acrylate. The mixture was homogenized at 80-100 ° C in a Buss-type continuous kneader and milled. The powder obtained can be used as a powder coating for electrostatic application. The film after curing 10 minutes / 196 ° C has excellent mechanical properties, good flow and is resistant to alkali, aliphatic and aromatic solvents.

Example 8

The procedure of Example 6 was followed, except that 6 g of bis [3- (1-morpholyl) propyl] amine was used instead of Ν, Ν-dimethyl-propylenediamine. The adhesive perfectly wets the surface of metal objects and, after curing, has excellent peel strength.

Claims (2)

OBJECT OF THE INVENTION A polyamine hardener for the curing of epoxy resins or their compositions with modifying agents and / or additives, characterized in that it consists of a mixture consisting of 40 to 97 wt. % of aliphatic and / or cycloaliphatic polyamines containing both primary and secondary amino groups in the molecule, the primary amino content of which is less than the ratio of one of these amino groups per 100 g of amine mass, and 3 to 60 wt. % of secondary amines containing at least one secondary amino group per 30 g of amine mass. 2. The polyamine hardener according to claim 1, characterized in that it is formed preferably by a technical mixture of amines formed by the hydrogenation of adducts of cycloaliphatic amines, in particular cyclohexyl amine, with acrylonitrile.