DE2321004A1 - CURATION OF POLYEPOXES - Google Patents

Description

Fr / Pk, 509 Leverkusen, Bayerwerk

April 25 W3

Hardening of polyepoxides

The present invention was based on the object of finding catalysts for epoxy resin compositions which on the one hand at room temperature a service life of several days and on the other hand at elevated temperatures one Hardening time of a few minutes. Such latent catalysts must also have the ability to prevent the sedimentation of the fillers usually used, such as quartz flour.

According to the current state of the art, the task cannot be solved. Boron trifluoride-amine adducts are known as latent catalysts, but this class of compounds has two serious disadvantages ^ Firstly, catalyze these substances essentially the etherification reaction of epoxy resins. As a result, acid anhydride hardeners cannot be used use which to achieve optimal 'molding material -

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properties are required and desired to lower the viscosity of the liquid epoxy resin compositions. Secondly do not prevent the quartz flour from settling.

Usually used as an accelerator for polyepoxide-acid anhydride mixtures The catalysts used are tertiary amines, such as dimethylbenzylamine or tris (dimethylaminomethyl) phenol. She. allow the desired short curing times at elevated temperatures, but are they are so effective even at room temperature that the service life is limited to a few hours due to the increase in viscosity will. .

The disadvantages described are avoided if one according to the present invention as catalysts mixtures of zinc compounds and amines, the at least contain a stearyl radical bonded to nitrogen, is used. These catalysts give the desired length Avoid using it for several days at room temperature or greatly delay the settling of the quartz powder and enable the same short hardening times with increased Temperatures such as the common tertiary amines mentioned above.

The value of the procedure according to the invention lies in a substantial simplification and rationalization of the cast resin technology. The long service life of the epoxy resin compounds makes it unnecessary to use complex and fault-prone cast resin processing systems with batch or continuous mixers. Rather, the need for cast resin compounds for one or more days can be covered by a single mixing process. Mixing errors are practically excluded and working time is saved. The claimed casting resin compositions can be used with particular advantage for injection molding processing according to German Offenlegungsschrift 2,017,506.
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The invention thus relates to an epoxy resin mixture made from polyepoxides with more than one epoxy group per molecule, one or more cyclic carboxylic acid anhydrides, optionally Flexibilizers, fillers and dyes as well as catalysts, characterized in that the catalyst consists of a mixture of a zinc compound and an amine, the contains at least one stearyl radical bound to nitrogen, consists.

As zinc compounds, the common salts such as zinc chloride, zinc sulfate, zinc stearate, zinc naphthenate and Zinc octoate, can be used. Certain zinc oxide grades can also be used. Preferably those are commercially available zinc naphthenates available as liquid products and Zinc octoate used.

Amines which can be used are those which contain at least one stearyl radical bonded to nitrogen. The following may be mentioned in particular: stearylamine, N-monoalkylstearylamine, N-dialkylstearylamine each with 1-22 carbon atoms, preferably 1-18 carbon atoms in the alkyl radical, N-monoarylstearylamine, N-diarylstearylamine (aryl = phenyl or naphthyl or through C ₁ - C.-alkyl-, C ₁ -C ^ -alkoxy-substituted phenyl or naphthyl), -N-distearylamine, N-alkyldistearylamine, N-aryldistearylamine, where alkyl and aryl have the same meaning as indicated above, tristearylamine.

The following are preferably used: stearylamine, N-methylstearylamine, Distearylamine, N-methyldistearylamine, tristearylamine.

Mixtures of several zinc compounds and several of the aforementioned amines can also be used.

The quantitative ratio of parts by weight of zinc compound: parts by weight of amine in the mixture can be 1:20 to 20: 1, preferably 1: 5 to 10: 1. The additional amount of

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Mixture, calculated on 100 parts by weight of polyepoxide, can be between 0.01 and 20 parts by weight, preferably between 0.1 and 10 parts by weight.

As polyepoxides, those aliphatic, cycloaliphatic, aromatic or heterocyclic compounds that on average have more than one epoxy group contained per molecule.

The polyepoxide compounds to be used can be polyglycidyl ethers polyhydric phenols, for example from pyrocatechol, resorcinol, hydroquinone, from 4,4'-dihydroxydiphenylmethane, from 4,4'-dihydroxy-3,3'-dimethyldiphenylmethane, from 4,4'-dihydroxydiphenyldimethylmethane, from 4,4'-dihydroxydiphenylcyclohexane, from 4,4'-dihydroxy-3,3 'dimethyldiphenylpropane, from 4,4'-dihydroxydiphenyl, from 4,4'-dihydroxydiphenyl sulfone, from tris (4-hydroxyphenyl) methane, from the chlorination and bromination products of the above-mentioned diphenols, from novolaks (i.e. from reaction products of monohydric or polyhydric phenols with aldehydes, especially formaldehyde, in the presence of acidic catalysts), from diphenols obtained by esterification of Moles of the sodium salt of an aromatic oxycarboxylic acid with one mole of a dihaloalkane or dihalodialkyl ether (see British patent 1,017,612) from Polyphenols, which are formed by the condensation of phenols and long-chain, Haloparaffins containing at least 2 halogen atoms were obtained (see British patent specification 1 024 288). Also mentioned are: polyepoxide compounds based on aromatic amines and epichlorohydrin, e.g. N-di- (2,3-epoxypropyl) -aniline, N, N'-dimethyl-N, N'-diepoxypropyl-4,4'-diamino-diphenylmethane, N, N'-tetraepoxypropyl-4,4'-diaminodiphenylmethane, N-Diepoxypropyl-4-aminophenylglycidether (cf. British patents 772 830 and 816 923).

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The following are also possible: glycidyl esters of polyvalent aromatic, aliphatic and cycloaliphatic carboxylic acids, for example diglycidyl phthalate, diglycidyl adipate and glycidyl ester of reaction products from 1 mol of an aromatic or cycloaliphatic dicarboxylic acid anhydride and 1/2 mol of a diol or l / n mol of a polyol with η hydroxyl groups or diglycidyl hexahydrophthalate, . Which can optionally be substituted by methyl groups.

Glycidyl ethers of polyhydric alcohols, for example from 1,4-butanediol, 1,4-butenediol, glycerine, trimethylolpropane, pentaetythritol and polyethylene glycols can also be used. Triglycidyl isocyanurate, N, N ^f -diepoxypropyloxamide, polyglycidylthioether oxamide such as polyglycidylthioether are of further interest for example from bismercaptomethylbenzql, diglycidyl trimethylene trisulfone, polyglycidyl ethers based on hydantoins. Finally, epoxidation products of polyunsaturated compounds may be mentioned, such as vegetable oils and their conversion products, epoxidation products of di- and polyolefins such as butadiene, vinyl cyclohexene, 1,5-cyclooctadiene, 1,5,9-cyclododecatriene, polymers and copolymers which still contain epoxidizable double bonds contain, for example based on polybutadiene, polyisoprene, butadiene-styrene copolymers, divinylbenzene, dicyclopentadiene, unsaturated polyesters, also epoxidation products from olefins, which are accessible by Diels-Alder addition and then converted into polyepoxides by epoxidation with per compounds or from compounds containing two cyclopentene or cyclohexene rings linked via bridging atoms or bridging atom groups. Polymers of unsaturated monoepoxides may also be mentioned, for example of glycidyl methacrylate or allyl glycidyl ether.

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The following are preferably used for the method according to the invention Polyepoxy compounds or their mixtures used: Polyglycidyl ethers of polyhydric phenols, in particular from bisphenol A; Polyepoxy compounds based on aromatic Amines, in particular bis (N-epoxypropyl) -aniline, N, N · -dimethyl-N, N'-diepoxypropyl-4,4'-diamino-diphenylmethane and N-diepoxypropyl-4-aminophenylglycidyl ether; Polyglycidyl ester from cycloaliphatic dicarboxylic acids, in particular Hexyhy.drophthalic acid diglycidyl ester and polyepoxides from the reaction product of η moles of hexahydrophthalic anhydride and 1 mole of a polyol with N hydroxyl groups (n = integer from 2-6), in particular 3 moles of hexahydrophthalic anhydride and one mole of 1,1,1-trimethylolpropane.

Preference is also given to using liquid polyepoxides or low-viscosity diepoxides such as bis (N-epoxypropyl) aniline or vinylcyclohexene diepoxide to further reduce the viscosity of already liquid polyepoxides or to convert solid polyepoxides into liquid mixtures.

All common di- and polycarboxylic acid anhydrides are used as acid anhydrides suitable. It is preferred to use liquid or easily melting dicarboxylic anhydrides, such as e.g. hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, Methyl-endomethylene-tetrahydrophthalic anhydride, Methyl tetrahydrophthalic anhydride, tetrahydrophthalic anhydride; of the latter two, the isomer mixtures are particularly suitable.

The curing takes place by mixing the polyepoxides with the liquid hardening agents according to the invention and optionally others Additives and heating to higher temperatures.

The mixing ratio is expediently chosen so that that there is approximately one anhydride group for an epoxy group;

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it can, depending on the desired properties of the polyadducts, more or less anhydride (about 0.1-2 mol of anhydride groups per epoxy group) can also be used. It. is also possible to add other other carboxylic acid anhydrides or other hardening agents in addition.

Curing may proceed at temperatures of about 60 ⁰ C to 250 ⁰ C, are preferably carried out at 8O ⁰ C to 180 ° C.

The hardening can also be interrupted at any time by cooling to e.g. room temperature and at a to be continued later. The time at which the implementation is interrupted is expediently chosen so that the mixture obtained when cooling to room temperature, for example, is in the B-state, i.e. is solid, and when it is heated later to the temperature of the final hardening becomes liquid again or becomes deformable under pressure. The application this last-mentioned process is particularly advantageous when laminates, Molding compounds and coating compounds, e.g. using the fluidized bed sintering process, be considered.

You can add fillers such as quartz powder, Chalk, aluminum oxide, pigments such as titanium dioxide, iron oxide, organic pigments such as phthalocyanine pigments, Flexibilizers such as polyglycols, polyether glycol, polyesters with terminal hydroxyl and / or carboxyl groups, Polysulphides, soluble dyes, reinforcing materials such as glass fibers, fabrics or plasticizers as well as mixtures add the above-mentioned additives in order to influence the properties of the hardening products.

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Example 1 :

100 Gew.-Tie hexahydrophthalic acid diglycidyl ester with a Epoxy equivalent weight of 170 is obtained with 100 parts by weight of methylhexahydrophthalic anhydride with an anhydride equivalent weight of 168, 4 parts by weight of a mixture of 100 parts by weight of stearylamine and 100 parts by weight of zinc octoate, and 300 parts by weight of quartz flour mixed.

Immediately after mixing, the viscosity is 4520 cP. After standing at 22 ° C for 24 hours, the viscosity is the mixture only marginally to 5100 cP and after 48 hours Standing increased to 6230 cP. After this time, the epoxy resin compound is still fully processable, quartz powder has not settled.

After placing in a hot mold at 150 ⁰ C, the mass hardens in 5 minutes to a solid plastic, on which the following properties are determined:

Flexural strength: 1300 kp / cm Impact strength: 11 kp.cm / cm Martens degree: 110 ⁰

If you take the same amount of dimethylbenzylamine instead of the catalyst mixture, the cast resin compound is already there after standing for 4 hours it increased to a viscosity of over 20,000 cP and thus no longer workable.

Example 2 :

100 parts by weight of bis (2,3-epoxypropyl) aniline with an epoxy equivalent weight of 120 are with 140 parts by weight of hexahydr © phthalic anhydride with an anhydride equivalent weight of 154, 2.5 TIn by weight of a mixture of 100 TIn by weight Methyl stearylamine and 400 parts by weight of zinc naphthenate, 370 TIn quartz powder and 10 wt.TIn iron oxide brown mixed.

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Immediately after mixing, the viscosity is 3200 cP. After standing at 22 ° C. for 24 hours, the viscosity is up 3530 cP and increased to 4060 cP after standing for 48 hours. The epoxy resin compound is still fully processable after this time, Quartz flour has not settled.

After introduction into a "to 150 ⁰ C heated form, the composition cures in 5 Minuten.zu of a solid plastic material, having the following features:

Flexural strength: 1050 kgf / cm

Impact strength: 7.5 kp.cm/cm Martens grade: 128 ⁰ C.

If, instead of the above-mentioned catalyst mixture, the same amount of tris (dimethylaminomethyl) phenol is used, after 4 hours of standing, the epoxy resin compound has risen to a viscosity of over 20,000 cP and can no longer be processed .

Example 3 : -

100 parts by weight of the diglycidyl ether of 4,4 ^f -dihydroxydiphenyldimethylmethane with an epoxide equivalent weight of 182 are with 80 parts by weight of an isomer mixture of tetrahydrophthalic anhydride with an anhydride equivalent weight of 162, 25 parts by weight of a polypropylene glycol of 2000, 3 parts by weight of a polypropylene glycol TiN by weight of a mixture of 100% by weight of methyl distearylamine and 200% by weight of zinc stearate and 150% by weight of quartz flour mixed.

Immediately after mixing, the viscosity is 6500 cP at 22 ° C. After standing for 24 hours, the viscosity is increased to 7200 cP and after 48 hours of standing to 8100 cP. Quartz flour did not settle and the mixture can still be fully processed after this time.

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After placing in a mold heated to 150 ° C, it hardens Mass to a solid plastic that has the following properties:

Flexural strength: 1350 kp / cm - -2

Impact strength: 13 kp.cm/cm Martens degree: 95 ⁰ C.

Used instead of the above-mentioned catalyst mixture. the same amount of hexahydro-dimethylaniline so is that After standing for 4 hours, the epoxy resin compound increased to a viscosity of over 20,000 cP and could no longer be processed.

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Claims (6)

Patent claims: 1. Thermosetting epoxy resin mixture of polyepoxides with more than one epoxy group per molecule, one or more cyclic carboxylic acid anhydrides, possibly flexibilizers, Fillers and dyes as well as catalysts> thereby characterized in that the catalyst of a mixture of a zinc compound and an amine, the at least one Contains stearyl radical bound to nitrogen, consists. 2. Thermosetting epoxy resin mixture according to claim 1, characterized in that the catalyst is the zinc compound and contains the amine in a weight ratio of 1: to 20: 1. 3. Thermosetting epoxy resin mixture according to claim 1, characterized in that the epoxy resin mixture is 0.01 up to 20 parts by weight of the catalyst mixture, based on 100 parts by weight of polyepoxide. 4. Thermosetting epoxy resin mixture according to claim 1, characterized in that the catalyst mixture as Zinc compound contains zinc naphthenate or zinc octoate. 5. Thermosetting epoxy resin mixture according to claim 1, characterized in that the catalyst mixture as Amine stearylamine, N-alkylstearylamine with 1-22 carbon atoms in the alkyl radical N-dialkylstearylamines with 1-22 carbon atoms each in the alkyl radical, distearylamine, N-alkylstearylamine with 1-22 C atoms in the alkyl radical tristearylamine or mixtures of these Contains amines. 6. Process for curing epoxy resin mixtures made from polyepoxides with more than one epoxy group per molecule, one or more cyclic dicarboxylic acid anhydrides and possibly Le A 15 052 - 11 - 4 09 846/0927 Flexibilizers, fillers, and dyes as well Catalysts in the heat, characterized. That. " a catalyst mixture of a zinc compound and an amine which has at least one stearyl radical bonded to nitrogen contains, is used; . Le A 15 032 - 12 - 409846/0927