DE2264286C3 - Use of 1,3,6,8-tetraazatricyclo-4,4,11 · 6 .l3 · 8 -dodecane as a hardener in the production of epoxy polyadducts - Google Patents

Description

It is known that epoxy compounds which contain more than one epoxy group in the molecule, also polyepoxides called, with hardeners, v / ie z. B. polyamines, cured to infusible and insoluble products can be.

Such products have - as is well known - a number of favorable properties, for example good strength, good adhesion and low shrinkage.

For some purposes, however, the hardness of the products made in this way leaves something to be desired. Above all, however, a major disadvantage of the amine hardeners is that they are physiologically very harmful and as liquid Products have a very high vapor pressure. In practice, therefore, they can only be large Precautions to be processed.

Boron trifluoride complex compounds are used to remedy this disadvantage and at the same time increase the curing rate has been suggested as a hardener. The complex compounds of boron trifluoride with basic N-containing compounds, such as ammonia, Amines and piperidine are suitable as hardeners at higher temperatures, while boron trifluoride-oxime complexes are cold-curing.

It is also known to act as reactants or in the manufacture of epoxy polyadducts Use accelerator hexamethylenetetramine. This compound contains ammonia in latent form, the. if it occurs intermediate, it escapes easily as a volatile compound.

The invention has for its object to find a Har'sr i \\ having the good properties of the amine curing agent, but is physiologically safe, and cured under the desired conditions in each case, that is at any desired temperature.

This object is achieved according to the invention by the use of iibe-tetraaza-tricyclo 4.4.1 ^{1 (1} 1 '"dodecane (TTC) in the production of epoxy adducts! Duidi polyaddition of epoxy compounds which contain more than one epoxy group in the molecule than Hardener in quantities ¹ of 0.03-1 mol per 1 epoxy equivalent at temperatures between 0 and 250 ° C.

Surprisingly, an amine hardener has been found which, on the one hand, has the good hardening properties of the known amine hardeners and leads to particularly high hardnesses, but on the other hand is physiologically harmless because as a solid product it has a very low vapor pressure and the amine is only present in it in latent form. This hardener is the 1,3,6,8-tetraazatricyclo-4,4, l ^{| 6} -l ³⁸ -dodecane or 1,6,3,8-di-endomethylene-UAS-tfitraaza-cycIo-decane, which is obtained by reacting Ethylenediamine and formaldehyde can be obtained in aqueous solution at ordinary temperature. Recrystallized from benzene, pyramidal-shaped

in moderate crystals; Mp. 196 ° C, bp. 250 ° C (Beils t ei η Vol. IV, p. 250; Ber. Chem. Ges. 31 [1898], p. 3254); in Ber. Chem. Ges. 95/1962, pp 1493-1494 formulated G. VoIpρ the compound as 1,4,6,9-tetraaza-tricyclo-4,4,1, l ⁴ - ° -dodecane.

The compound tetraatricyclo-dodecane used according to the invention, hereinafter referred to as TTC for short is a very interesting compound, which is similar to hexamethylenetetramine in the fore methylene groups bonded between the nitrogen atoms, latent formaldehyde, but also contains latent ethylenediamine, which has the desired advantage that the hardener is only below each suitable conditions can be made to start. TTC is as it is non-volatile j Ethylenediamine bound in latent form, preferable to hexamethylenetetramine. Also has Surprisingly shown that TTC leads to better hardnesses.

In US-PS 34 28 601 a diethylenetetrame-

JO thylenetetramine called compound described. the end the preparation and melting point of this compound are to be inferred to be identical to TTC. the US-PS teaches that this compound together with a aromatic compound containing at least one pheno-

s ") lisch bonded hydroxyl group and a free ortho or para position, as a hardener for epoxy resins can serve. Per equivalent weight of diethylene-tetramethylene-tetramine 0.5-3 equivalent weights of this aromatic compound are used.

■ χι It has now surprisingly been found that TTC Used alone, it leads to products with significantly higher flexural strength, as a comparison below shows Example 3 with subsequent example 3a shows. Another major benefit of the

4Ί Invention over that known from the US-PS The hardener system consists in the fact that the hardener is physiologically due to the elimination of the phenolic component is safe and much easier to manufacture. According to the invention, solid or liquid polyepo

Vi xide. for example the diglyci''yl compound of 4.4 Dioxidiphenylmethans. of isopropylamine or higher molecular precondensation of these epoxy compounds with correspondingly higher epoxy equivalents. hereinafter referred to as epoxy resin, or F.poxy-

Yt compounds based on cycloaliphatic alcohols or epoxy compounds, such as vinylcyclohexene diepoxide or other liquid or solid polyepoxy compounds. be used / t.

When it comes to hard, one can proceed in such a way that one does that

wi TTC in finely powdered form a solid polyepoxide ziiniisi ht or dissolve under mild conditions in a liquid epoxy resin and then let this mixture harden through. It is also possible to first apply TTC in a solvent such as a ketone,

<>■> to dissolve and then to mix in the liquid epoxy resin or to mix a solution of TTC with a solution of the polyepoxy compound.
TTC is used in a ratio of 0.03 to 1 mol

to 1 epoxy equivalent of the polyepoxide or the Admixed with epoxy resin. An epoxy equivalent of the epoxy resin corresponds to, depending on the type of Epoxy Compound 100 to 10,000 grams of the epoxy compound. Accordingly, the proportions between TTC and epoxy resin can be very different.

Curing can be carried out at temperatures between 0 and 250 ° C. For example, cold hardening is used at 20 to 30 ° C, in the heat for example at 30 to 100 ° C or in the heat at temperatures above 100 ° C. The most favorable conditions in each case can easily be determined by a person skilled in the art. the Conditions can also be chosen so that curing proceeds relatively quickly it may be favorable to harden at rising temperatures or post-hardening, which is based on hardening and subsequent cooling follows.

Mixtures of polyepoxides, for example combinations of the diglycidyl compound des Dioxidiphenylpropans and the diglycidyl compound of isopropyl lamb can be combined with the Tetraaza compound harden.

The epoxy polyadducts can be modified in various ways, e.g. B. by mixing with others Compounds before curing, by modifying the starting epoxides, by combining TTC with other hardeners, such as carboxylic acid anhydrides, or by adding modifiers during hardening.

Suitable modifiers are difunctional alcohols such as glycols or tri- and tetrafunctional alcohols. The products nes bifunctional alcohol, for example ethylene glycol, a flexibility possible in cases of large amounts nI glycol, the glycol is then condensed with offfensichtlich Prior to ^curing; as is by the addition of 0.005 to 5 mol, preferably from 0.05 to 'moles, ".. If desired, fillers, pigments and other known additives can be incorporated.

The products cured by using the TTC according to the invention, such as casting resins, pressed parts or Lacquers, have very favorable properties. The hardnesses achieved are very high, the hardened products have good elastic properties, adhesive strengths and very low shrinkage.

Because of their favorable properties, those hardened by the use of TTC according to the invention Versatile products.

The invention is well suited for the production of impregnating or dipping paints, but also for powder paints as well as for baking enamels.

The invention is also suitable for production of laminates, for example glass fiber reinforced laminates. Casting har / s. for molding and insulating materials or, in combination with suitable fillers, like fine stone flour. Asbestos. Mica. Wood flour or Baiim wool fibers. for the production of molding compounds.

fpoxul compounds. to which TTC was added as a hardener is. are suitable for measuring dimensions. for example / ur Manufacture of molded plastic materials for manufacture abrasion-resistant covers, for grinding wheels, as hot and Kallkfebende adhesive resins, as modifiers and Crosslinking agents, for example in the case of natural and synthetic rubber.

The resin / hardening combinations obtained using TTC according to the invention can also as binders, for example core sand binders, molding sand binders or for crosslinking novolaks to be used. Under suitable conditions they are available as foam resins and also as additives applicable.

Example!

In 4 epoxy equivalents of a liquid epoxy resin based on Dioxidiphenylpropane diglycidyl ether, with the epoxy equivalent of 180, 1 mol, corresponding to 168 g of TTC, was dissolved. The mixture was then dissolved IU potted and 1 hour each at 60, 80, 100, 120 and 140 ° C hardened and post-hardened for 4 hours at 110 ° C

A brown elastic synthetic resin was obtained which, as a film with a thickness of 100 μ on a glass plate applied, had final pendulum hardnesses (determined according to DIN 53 157) of 190 with a cross-cut of 1.

If, on the other hand, the epoxy resin was cured with equal amounts of hexamethylenetetramine instead of TTC, it showed the film only has a pendulum hardness of 50.

Example 2

168 g, corresponding to 1 mol of TTC, were in a mixture of 600 g, corresponding to 3.3 epoxy equivalents, of a liquid epoxy resin based on 4,4-DioxidiphenyI-propane diglycidyl ether and 90 g, ent-2> Speaking 1 epoxy equivalent, from Diepoxipropyl-isopropylamine solved.

The mixture was then hardened at 60, 70, 80, 100, 120 and 140 ° C. for 1 hour each.

Was obtained a hard, elastic, light brown in synthetic resin, which, as a film of 100 μ thickness on a Glass plate applied, final pendulum hardnesses of 198 with a cross-cut of 1 - 2 showed.

If, on the other hand, the epoxy resin was cured with equal amounts of hexamethylenetetramine instead of TTC, it showed r. the film only has a pendulum hardness of 65.

Example 3

1 mol, corresponding to 168 g, of TTC was in a mixture of 5 epoxy equivalents, correspondingly

in 720 g, of a liquid epoxy resin based on 4,4-Dioxidiphenylpropane digIycidyläther to 1 mol, corresponding to 62 g, glycol dissolved with gentle heating. That combination then got slow heated and one hour each at 60, 70, 80, 100, 120,

4-1 140 ⁰ C cured.

A very elastic, hard, solid synthetic resin with a flexural strength of 771 kg / cm ^{2 was obtained} .

_{V |} Example 3a (comparative example)

In 900 g. corresponding to 5 epoxy equivalents. a liquid epoxy resin based on 4,4-Dioxi-diph'nylpropane diglycidyl ether were initially 168 g, corresponding to 1 mol. TTC and then under > ■> mild conditions 125 p. corresponding to 1.33 MnI. Phenol dissolved

This mixture was heated slowly and for 1 hour each time at 60. 70.80. 100, 120 and 140 "C held.

Ls Obtained as a light brown solid, very hard n> resin having a flexural strength of 424 kgf / cm '.

Example 4

For the production of a varnish resin mixture

'· <400 g, corresponding to 0.4 epoxy equivalents, one solid epoxy resin based on 4,4-Dioxidiphenylpropane-Glycidäther and 0.1 mol, corresponding to 6.8 g,

TTC in 200 g of methyl ethyl ketone to an approximately 68% strength

Solution solved. This solution was then applied to glass plates and cured under various conditions. After a cure of 24 hours at 20 ⁰ C already yielded a pendulum hardness of 56 see. After curing for 6 hours at] 20 ° C, the pendulum hardness was] 95 seconds. On the other hand, paint films produced under the same conditions with ethylenediamine, diethylenetriamine, Tnäthyientejramin as hardener only lead to final pendulum hardnesses between 76 and 140 seconds,

Claims (3)

Patent claims: 1. Use of 1,3,6,8-tetraaza-tricyclo-4,4,11.6. iw-dodecane (TTC) in the production of epoxy polyadducts by polyaddition of epoxy compounds, which contain more than one epoxy group in the molecule, as hardeners in amounts of 0.03 - 1 Mol per 1 epoxide equivalent at temperatures between 0 and 250 ° C 2. Use according to claim 1, characterized in that TTC together with any the known amine or acid anhydride hardeners is used. 3. Use according to claim 1 or 2, characterized in that 0.005-5 mol of a di-, tri- or tetrafunctional alcohol, based on 1 mol of TTC, is added as a modifier.