WO1999028365A1

WO1999028365A1 - Adducts of aromatic monoepoxy compounds and norbornanediamine

Info

Publication number: WO1999028365A1
Application number: PCT/EP1998/007463
Authority: WO
Inventors: Wolfgang Scherzer; Jörg Volle
Original assignee: Ciba Spezialitätenchemie Bergkamen Gmbh
Priority date: 1997-11-28
Filing date: 1998-11-20
Publication date: 1999-06-10

Abstract

This invention relates to adducts containing free active hydrogen bound to amino nitrogen atoms, obtainable by reacting: A) 2,5(2,6)bis(aminomethyl)bicyclo(2,2,1)heptane (norbornanediamine) of formula (1) with B) an aromatic monofunctional epoxy compound of general formula (2) wherein R1, R3, R5 are each independently of one another H or an unbranched or branched alkyl radical containing 1 to 10 carbon atoms, R2, R4 are H, and R6 is a radical of formula (3), using at most 2 mol of the compound of general formula (2) per mol of the compound of general formula (1), to a process for the preparation of these adducts and to curable mixtures comprising these adducts.

Description

Adducts of aromatic monoepoxy compounds and norbomanediamine

Curable mixtures based on amine hardeners and epoxy resins are widely used in the industry for coating and improving metallic and mineral substrates. The amine hardeners used are, in particular, aliphatic, cycloaliphatic or aromatic amines as well as, optionally, imidazo- line group-containing polyaminoamides and adducts thereof.

The mechanical and physical properties of the curable mixtures based on these amines are sufficient for many applications.

However, especially the decorative field (coating lacquer, industrial flooring etc.) requires binder systems having high UV resistance after curing and uniformly good surface qualities in the range from 5 to 25 °C.

Another requirement is that, even at low temperatures, the binder systems are rapidly cured after being applied to the substrates to make them e.g. quickly passable or recoatable.

Essential criteria are high early water resistance of the still unhardened film (e.g. by drop formation at high relative atmospheric humidity) as well as low viscosity of the binder system to ensure its processability even at low temperatures.

Mannich bases, i.e reaction products of amines and formaldehyde with a phenolic component, are known as hardeners for epoxy resins which develop a hardness that is to some extent satisfactory at low temperatures.

In recent years a great number of publications and patents have been published on this product type.

Examples which may be mentioned are JP Hei 7-507900, JP Hei 7-5117899 or USP 4,269,742. The disadvantage of the systems proposed therein is on the one hand their high viscosity and, on the other hand, the bad UV resistance of the cured coatings owing to the phenolic components present in these systems.

EP 0 288 975 describes adducts of monoepoxy compounds and specific diamines which can be used at very low temperatures. However, these compounds also need to be accelerated with salicylic acid, phenol, alkylphenol or with a Mannich base. These accelerators in turn also produce bad UV resistance.

WO 96/34032 describes adducts of cycloaliphatic di- or polyglycidyl ethers with norbomanediamine, if required using in addition acrylates or methacrylates. Although these products have to some extent good UV resistance, the development of the hardness of these systems (measured in accordance with Shore D) is far too low even at room temperature; the surface properties of the cured films are insufficient for many applications and the viscosities of the amine adducts are very high in spite of a high diluent proportion of about 45 %.

The object of this invention is therefore to overcome these disadvantages and to provide hardeners for binder systems which, at high UV resistance and low viscosity, provide the cured systems with a rapid complete cure and with uniformly good surface properties both at room temperature and under unfavourable curing conditions, such as at low temperatures and/or high relative atmospheric humidity.

This object is achieved by the inventive adducts of monofunctional aromatic epoxy compounds and norbomanediamine.

Accordingly, this invention relates to adducts containing free active hydrogen bound to amino nitrogen atoms, which are obtainable by reacting

A) 2,5(2,6)bis(aminomethyl)bicyclo(2,2,1)heptane (norbomanediamine) of formula (1)

with

B) an aromatic monofunctional epoxy compound of the general formula (2)

wherein

Ri , R3, R5 are each independently of one another H or an unbranched or branched alkyl radical containing 1 to 10 carbon atoms,

R2, R4 are H, and

RQ is a radical of formula ² y7 . V7 using at most 2 mol of the compound of the general formula (2) per mol of the compound of the general formula (1). It is preferred, however, to use a molar ratio of 1 :1.

The novel adducts are prepared by known processes by placing the diamines in a vessel and adding the aromatic monoepoxy compounds dropwise, with stirring, at 60 to 80 °C and then stirring this mixture for about 1 hour (h) at that temperature until the adduct formation is complete.

So-called "isolated adducts" are also used, which are prepared with an excess of norbor- nanediamine (NBDA). To this purpose the 1.5- to 10-fold, preferably the 4- to 6-fold, molar amount of amine is placed in a vessel and the aromatic monoepoxy compound is added dropwise, with stirring, conveniently at 60 to 80 °C. Excess amine is then removed by distillation under vacuum.

In another of its aspects this invention thus relates to a process for the preparation of the adducts according to claim 1 , which process comprises

A) heating a norbomanediamine of the general formula (1) to the reaction temperature and adding, with continuous stirring,

B) an aromatic monofunctional epoxy compound of the general formula (2), removing, if required, excess component A) from the reaction mixture after the adduct has formed.

The reaction temperature is not critical and may thus be varied but is conveniently from 60 to

80 °C.

This invention also relates to curable mixtures consisting of

I) an adduct according to claim 1 , and about equivalent amounts, based on free active hydrogen bound to amino nitrogen atoms and epoxy groups,

II) of an epoxy compound having on average more than one epoxy group per mol, if required using in addition diluents (C), aliphatic and/or cycloaliphatic amines (D), mono- or higher- functional epoxy compounds (E).

The novel adducts are preferably adjusted with the components (C) to (E) to a user-friendly mixture ratio of 50 parts of hardener (adducts I) per 100 parts of resin (component II). However, depending on the desired final properties the mixture ratios can also vary from 30 to 100 parts of hardener/100 g of resin. The diluent proportion should not exceed 40 %, based on the hardener, since this would result in too great a drop in the mechanical data. The ratio between reactive groups of the adducts according to (I) and, optionally, the amines according to (D) and the epoxy groups (II) and, optionally, the higher- or monofunctional glycidyl ethers according to (E) is preferably adjusted about equivalently.

As diluent according to (C) it is possible to additionally use the alcohols and or ethers customarily used in this field, in particular benzyl alcohol and ethylene glycol monomethyl ether.

According to this invention the preferred aliphatic or cycloaliphatic amines of (D) are isopho- ronediamine, bisaminomethylcyclohexane and/or 2,4,4(2,2,4)-trimethylhexamethylenedi-1 ,6- amine.

According to this invention, the mono- or higher-functional glycidyl ethers (E) according to claim 4 are preferably ethylhexyl glycidyl ether, hexanediol diglycidyl ether, butanediol digly- cidyl ether, cyclohexanedimethylol diglycidyl ether, diethylene glycol diglycidyl ether, poly- oxypropylene diglycidyl ether and glycidyl ether based on bisphenol A, bisphenol F and novolaks.

The epoxy compounds (component II) additionally used in accordance with this invention are commercially available products containing at least one epoxy group per molecule and are derived from mono- and/or polyvalent and/or polynuclear phenols, in particular bisphenols, and from novolaks, such as diglycidyl ethers of bisphenol A and bisphenol F.

An extensive enumeration of these epoxy compounds is to be found in the compendium "Epoxidverbindungen und Epoxidharze", A. M. Paquin, Springer Verlag, Berlin, 1958, chapter IV, and in Lee & Neville, "Handbook of Epoxy Resins", 1967, chapter 2. It is also possible to use mixtures of two or more epoxy resins. It is preferred to use mixtures of the resins together with so-called reactive diluents, such as butyl glycidyl ether, cresyl glycidyl ether, 2-ethylhexyl glycidyl ether and the like.

It is also possible to add the standard additives to the novel curable mixtures, for example fillers, pigments, colourants, solvents, plasticisers, stabilisers, flow control agents, non-reactive extender resins. It is not necessary to add additional accelerators.

As binders for synthetic resin mortar, standard pebbles and sands are additionally used in the grain size distributions and amounts customarily used in this field.

Examples

Example 1

450 g of norbomanediamine (NBDA) and 320 g of benzyl alcohol are placed in a reaction vessel. After heating this mixture to 60 to 80 °C, 230 g of cresyl glycidyl ether (epoxy value: about 0.55) are added dropwise, with stirring, over 30 min, keeping the temperature within this range by cooling. To ensure complete adduct formation, stirring is continued for 60 min at 60 °C to 80 °C.

Viscosity: 210 mPa.s /25 °C; H equivalent: about 95

Example 2

450 g of NBDA, 230 g of phenyl glycidyl ether (epoxy value: about 0.58) and 320 g of benzyl alcohol are reacted according to Example 1.

Viscosity: 230 mPa.s /25 °C; H equivalent: about 95

Example 3

450 g of NBDA, 230 g of p-tert-butylphenyl glycidyl ether (epoxy value: about 0.45) and

320 g of benzyl alcohol are reacted according to Example 1.

Viscosity: 205 mPa.s /25 °C; H equivalent: about 95 Example 4

450 g of NBDA, 150 g of cresyl glycidyl ether (epoxy value: about 0.55), 80 g of diglycidyl ether of bisphenol A (equivalent weight: 0.575) and 320 g of benzyl alcohol are reacted according to Example 1.

Viscosity: 455 mPa.s /25 °C; H equivalent: about -95

Example 5

450 g of NBDA, 150 g of cresyl glycidyl ether (epoxy value: about 0.55), 80 g of ethylhexyl glycidyl ether (epoxy value: about 0.32) and 320 g of benzyl alcohol are reacted according to

Example 1.

Viscosiy: 160 mPa.s /25 °C; H equivalent: about -95

Example 6

450 g of NBDA, 150 g of phenyl glycidyl ether (epoxy value: about 0.58), 80 g of hexanediol diglycidyl ether and 320 g of benzyl alcohol are reacted according to Example 1.

Viscosity: 320 mPa.s /25 °C; H equivalent: about -95

Example 7

230 OF NBDA, 240 g of isophoronediamine (IPD), 230 g of cresyl glycidyl ether (epoxy value: about 0.55) and 300 g of benzyl alcohol are reacted according to Example 1.

Viscosity: 270 mPa-s /25 °C; H equivalent: about -95

Example 8 (isolated adduct)

2370 g of NBDA are placed in a vessel and heated to 60 to 80 °C. 540 (~3 mol) of cresyl glycidyl ether (epoxy value -0.55) are then run into it, the temperature increasing to about 100 °C. After further heating to 200 °C, vacuum is applied and the pressure is reduced to 30 mbar over 30 min while removing excess norbomanediamine by distillation, which gives an isolated adduct having the following characteristic numbers:

Amine value: 335; NH equivalent: 112 Example 9

460 g of the isolated adduct of Example 8 are mixed at -70 °C with 250 g of IPD and 290 g of benzyl alcohol.

Viscosity: 400 mPa.s /25 °C; NH equivalent: about 95

Example 10

460 g of the isolated adduct of Example 8 are mixed at -70 °C with 226.5 g of NBDA and

313.5 g of benzyl alcohol.

Viscosity: 360 mPa.s /25 °C; NH equivalent: about 95

Example 11

119 g of NBDA, 281 g of cresyl glycidyl ether (epoxy value: about 0.55), 380 g of IPD and

220 g of benzyl alcohol are reacted according to Example 1.

Viscosity: 310 mPa-s /25 °C; H equivalent: about 95

Example 12

119 g of NBDA (0.77 mol) are placed in a vessel and mixed with 256 g of benzyl alcohol. 281 g (1.54 mol) of cresyl glycidyl ether are adducted according to Example 1. Subsequently, 344 g of NBDA are added and homogenised.

Viscosity: 290 mPa-s /25 °C; H equivalent: about 95

Example 13

1540 g (10 mol) of NBDA are placed in a vessel. 1200 g of styrene oxide (10 mol) are added dropwise at 60 to 80 °C over 60 min and the mixture is then stirred for 30 min.

NH equivalent: about 91.

Example 14

784 g of the adduct of Example 13 are homogenised with 216 g of benzyl alcohol at about

60 °C.

Viscosity: 610 mPa.s /25 °C; NH equivalent: about 115 Example 15

530 g of the adduct of Example 13 are homogenised with 200 g of IPD and 270 g of benzyl alcohol at about 60 °C.

Viscosity: 280 mPa-s /25 °C; NH equivalent: about 95

Example 16

320 g of the adduct of Example 13 are homogenised with 300 g of IPD and 380 g of benzyl alcohol at about 60 °C.

Viscosity: 160 mPa-s /25 °C; NH equivalent: about 95

Example 17

530 g of the adduct of Example 13 are homogenised with 181 g of NBDA and 289 g of benzyl alcohol at about 60 °C.

Viscosity: 185 mPa-s /25 °C; NH equivalent: about 95

Comparison Examples

Comparison Example 1

330 g of 1 ,2-diaminocyclohexane, 230 g of cresyl glycidyl ether and 440 g of benzyl alcohol are reacted according to Example 1.

Viscosity: 60 mPa-s /25 °C; NH equivalent: 95

Comparison Example 2

490 g of IPD, 230 g of cresyl glycidyl ether and 280 g of benzyl alcohol are reacted according to Example 1.

Viscosity: 385 mPa.s /25 °C; NH equivalent: 95

Comparison Example 3

390 g of xylylenediamine, 230 g of cresyl glycidyl ether and 380 g of benzyl alcohol are reacted according to Example 1. Viscosity:80 mPa.s /25 °C; NH equivalent: 85

Methods of analysis

Viscosity

Measurement is carried out using a Haake rotary viscometer RV20 in accordance with the instructions of the producer.

Gel time

Measurement is carried out using the Tecam gelation timer GT3, of Techne.

Early water resistance/blushing of the film on exposure to water

Preparation of the samples:

The calculated amounts of epoxy resins and amine hardener are weighed into a mixing vessel and are vigorously mixed with a spatula for about 2 min without working in any excess air. Local inhomogeneities show as streaks and are to be avoided.

A 500 μm film transfer frame, of Erichsen, is placed on a glass plate which has been cleaned first with acetone and then dried, and this frame is then filled with about 15 g of the reactive mixture and drawn evenly over the free area. The freshly coated glass plates are immediately laid out into the corresponding climatic chambers, typically at relative atmospheric humidity (r.h.) at 23 °C/r. h. about 95 %. at 10 °C/r. h. about 80 % at 5 °C/r. h. > 70 %.

After curing for 24 hours, the glass plates are taken back to the test laboratory for assessment of their surface.

Each test is rated (in accordance with DIN 53230):

0 = flawless up to 5 = most flaws.

Graduations of 0.5 are possible for fine differentiation e.g. with comparison samples. On each plate, about 0.5 ml of completely desalted water is applied to one site using a pipette and is then dabbed off after 60 min with cellulose.

The extent of coloration/blushing of the film at the site exposed to water is assessed.

UV yellowing (DIN 5033)

Measurement is carried out using the colorimeter Minolta CR 200 = 150 h 50 °C.

Table 1 : Test results

diluted with a glycidyl ether based on a monofunctional fatty alcohols; equivalent: 194

Claims

What is claimed is

1. An adduct containing free active hygrogen bound to amino nitrogen atoms, obtainable by reacting

with

B) an aromatic monofunctional epoxy compound of the general formula (2)

wherein

Ri i R3) R₅ are each independently of one another H or an unbranched or branched alkyl radical containing 1 to 10 carbon atoms,

R₂, R₄ are H, and

-O-CH

Re is a radical of formula 7 , ^~Y7

O O using at most 2 mol of the compound of the general formula (2) per mol of the compound of the general formula (1).

2. An adduct according to claim 1 , wherein aliphatic and/or cycloaliphatic amines are additionally used.

3. An adduct according to claim 2, wherein the aliphatic and/or cycloaliphatic amines additionally used are isophoronediamine, bisaminomethylcyclohexane, 2,2,4(2,4,4)trimethylhexa- methylene-1 ,6-diamine.

4. An adduct according to any one of claims 1 to 3, wherein at least one mono- or higher- functional glycidyl ether is additionally used.

5. An adduct according to claim 4, wherein the mono- or higher-functional glycidyl ether additionally used is ethylhexyl glycidyl ether, hexanediol diglycidyl ether, butanediol diglycidyl ether, cyclohexanedimethylol diglycidyl ether, diethylene glycol diglycidyl ether, polyoxypro- pylene diglycidyl ether and glycidyl ethers based on bisphenol A, bisphenol F and novolaks.

6. A process for the preparation of the adduct according to claim 1 , which comprises

A) heating a norbomanediamine of the general formula (1 ) to the reaction temperature and adding, with continuous stirring,

7. A curable mixture, consisting of