FR2518541A1 - CARBOXAMIDES CONTAINING AMINO GROUPS, PROCESS FOR PREPARING THEM AND APPLICATION AS HARDENERS OF EPOXY RESINS - Google Patents

Abstract

THE INVENTION RELATES TO NEW COMPOUNDS WHICH ARE DICARBOXAMIDES BEARING AMINO GROUPS. THEY RESPOND TO THE FORMULA: (CF DRAWING IN BOPI) IN WHICH REPRESENTS AN AROMATIC, CYCLOALIPHATIC OR ALIPHATIC RADICAL WHICH CARRIES THE TWO CARBONYL GROUPS REPRESENTED ON THE FORMULA IN POSITIONS NEAR ONE IN RELATION TO THE OTHER, AND R REPRESENTS A RADICAL ARYLENE, ARALKYLENE, CYCLO-ALKYLENE OR CYCLO-ALKYL-ALKYLENE. THEY CAN BE PREPARED BY REACTING THE ANHYDRIDE OR THE IMIDE OF A HOCO-Y-COOH DIACID WITH A HN-R-NH DIAMINE. THESE COMPOUNDS CAN BE USED AS LATENT HARDENERS FOR EPOXIDIC RESINS. MIXTURES BASED ON EPOXIDIC RESINS THAT CONTAIN SUCH HARDENERS HAVE EXCELLENT STABILITY IN STORAGE.

Description

The present invention relates to particular amino carboxamides which

  are latent hardeners for epoxy resins, and it also relates to mixtures which

  contain such amides and epoxy resins.

  Already known, for example by the patent U 53 759 914, amines, amine derivatives and substituted amines

  which are suitable as latent hardeners for epoxy resins

  diques latent hardeners derived from acid anhydrides

  and linear aliphatic polyamines are described by -

  for example, US Pat. Nos. 3,261,882, 3,488,742 and 3,636,657.

  Note in particular the reaction product derived from phthalic anhydride and diethylene triamine, which is

  mentioned in these US patents.

  The new compounds which are the subject of the present invention form a new class of latent hardeners whose properties are better use. They are mixed with epoxy resins and they remain stable for several months.

  month at room temperature or at a light temperature-

  However, at relatively high temperatures, they harden the epoxy resin in a relatively short time, for example in 10 to 60 minutes at a temperature of 150 ° C, by transforming said epoxy resin into a product that has very good properties. properties, and that it uses a freshly prepared mixture or a mixture that has been stored for several months. This is a matter of astonishment because the amides according to the invention contain free amino groups that could be expected to that they react with the epoxy groups from room temperature The improvement of the properties in use rests above all on the improvement of the thermal stability and the resistance to the water as well as on the rise of the temperature of glass transition transition hardened epoxy compounds The mixtures of the amides according to the invention with epoxy resins can therefore have many applications, for example example in the manufacture of sheets

  prepreg as well as in the manufacture and repair of

composite structures.

  The compounds according to the invention correspond to formula I

0 O

He He

H 2 NR NH C Y C -NH R NH 2 (I),

  in which Y represents an aromatic radical, cyclo

  aliphatic or aliphatic group to which the two carbonyl groups represented on the formula are connected in positions close to each other, and R represents a radical

  arylene, aralkylene, cycloalkylene or cycloalkylalkylene.

  The symbol Y present in Formula I preferably represents the radical of phthalic acid, tetrahydro-phthalic acid, methyltetrahydro-phthalic acid, hexahydro-phthalic acid, succinic acid, dodecylsuccinic acid or maleic acid or the radical of such an acid carrying one or more C 1 -C 4 alkyl radicals, in particular bearing one or more methyl radicals; Y is more particularly the

radical of phthalic acid.

  In formula I the symbol R preferably represents

  a phenylene radical which may carry radicals

  C 1 -C 4 alkyls, a xylylene radical or a cycloalkyl radical

  hexylene This will be more particularly radicals pro

  from the following compounds by removal of both groups

  amino: m-xylylene-diaminem-phenylenediamine, p, p'-methylene-

  dianiline, bis (p-aminophenyl) sulfone, diamino-11,2

  hexane, diamino-1,4 cyclohexane, bis (p-aminocyclohexyl)

  methane, bis- (aminomethyl) -1,3 cyclohexane, bis- (4-amino-3-methylcyclohexyl) -methane, bis (4-aminocyclohexyl) -2,2 propane, 3,5-trimethylaminomethyl- 3 cyclohexylamine

  (isophorone diamine) and amino-6 (4-aminophenyl) trimethyl-

  1.3.3 indane The radicals of mxylylene diamine, 1,2-diamino cyclohexane, bis (p-aminocyclohexyl) methane and bis (aminomethyl) -1,3 cyclohexane are particularly preferred. The compounds of formula I can be prepared according to the invention by reacting a compound corresponding to one of the formulas I Ia and I Ib Y / O (I Ia) Y \ 1 H (I Ib )

C = O C = O

with an amine of formula III

H 2 N R NH 2 (III).

  There is then a condensation reaction with

  nucleation of the anhydride or imide nucleus and removal of water or-

  Ammonia respectively It is good to use an excess of the amine more precisely the amount of amine put into play may be only slightly greater than the stoichiometric amount but it can also be much higher,

  for example, represent up to 100% of the molar amount.

  The reaction product can be isolated without difficulty in

  removing the excess amine by distillation under high pressure

pick.

  The reaction is suitably carried out in accordance with the general method described by Spring and Woods in Journal of the Chemical Society 1945, pp. 625-628. This is an aqueous process performed at temperatures of 20 to 500 C, the best being to mix the components at 300 C

  and to carry out the reaction below 50 ° C -

  Usually the reaction is carried out under normal pressure but it can also operate under reduced pressure. It is also possible to carry out the reaction by the method described in US Pat. No. 3,639,657, although some of the hardeners thus prepared tend to react too rapidly with epoxy resins. meaning that the reaction is carried out in solution in dioxane, then the product is carefully purified The products that form are generally solid and vritrous substances which

melt at low temperature.

  The reaction of acid anhydrides with diamines does not always lead to pure diamides; ordinarily mono-amides are also formed, which can be

  separate either leave in the mixture with the diamides.

  if the reaction products can be mixed with an epoxy resin by known methods (stirring,

  mixing, rolling, etc.) Epoxy resins are used.

  diques which contain more than one epoxy group in the average molecule. For example, poly-glycidyl ethers of polyphenols, such as bisphenol A, bis

  phenol F and bisphenol S, novolaks derived from

  and phenol, glycidylated hydantoins, glycidylated aromatic amines, glycidylated aminophenols, polyglycidyl esters and certain epoxy resins

  Cycloaliphatics Preferred is methylene

  tetraglycidyl dianiline; the ethers-based resins

  Glycidylics of bisphenol A are also appreciated in the art of glues, coatings and coils

of son.

  With respect to the epoxy resin, the compounds

  according to the invention may be involved in quantities

  As these compounds represent from 50 to 150%, preferably 100%, of the stoichiometric amount. When reacted at relatively high temperatures with polyepoxides, for example diepoxides, the compounds of the invention lead to

  highly crosslinked products that are infusible and insoluble.

  By giving at the same time to the mixtures the desired shape by casting or molding, it is possible to manufacture cast objects,

  molded parts or laminates It is also possible to apply

  mix the resin and hardener mixtures on substrates and cure them as a coating, paint, varnish or bonded assembly.

  Such systems are frequently used in

  It can be used to pre-impregnate fibers of different types, such as graphite fibers, glass fibers or Kevlar fibers which

  can then be used for the manufacture of boron-

  These systems are also suitable for the production of laminates. Laminates can be manufactured by known techniques, in particular

  by compression molding, or by the autoclave method.

  The layer thicknesses of these laminates can be

very variable.

  Mixtures of compounds of formula I with epoxy resins can be added other usual constituents,

  such as diluents, fillers, reinforcing agents

  Pigments, dyes, organic solvents, flame retardants, thixotropic agents, fluxing agents and the like. Examples of suitable diluents, reinforcing agents and pigments are:

  coal tar, bitumen, fiberglass, fi-

  boron borers, carbon fibers, cellulose, powder

  polyethylene, polypropylene powder, mica,

  ante, quartz powder, calcium sulphate, antimony oxide, montmorillonite derivatives (such as "Bentone"), silica airgel ("Aerosil"), lithopone, barytite, dioxide of titanium, carbon black, graphite, iron oxide and metal powders such as aluminum powder or iron powder.

  in particular silicones, aceto

  cellulose butyrate, polyvinyl butyral, waxes, stearates and the like, which can sometimes

  also serve as release agents.

  In glues containing an epoxy resin and

  a compound of formula I there may also be

  such as an acrylic rubber

  nitrile / butadiene having terminal carbonyl groups, modifying resins, such as triglycidylated p-amino phenol, accelerators, such as boron trifluoride / monoethylamine complexes or imidazole complexes, or other hardeners, such as cyanoguanidine

  In the examples that follow the parts and the

percentages are by weight.

EXAMPLE 1

  To a solution of m-xylyiene diamine in dioxane, which solution is boiled under nitrogen at reflux (110 ° -120 ° C.), is added dropwise a solution of phthalic anhydride in dioxane. in a quantity

  such that there are 4 moles of the amine per 1 mole of the anhy-

  After 80 minutes the addition is complete, and the mixture is maintained at 110-120 ° C. for 2 hours. The water formed and the dioxane are removed under reduced pressure until the solution has become viscous. successively hot heptane, toluene, hexane and diethyl ether until a solid body is formed with a yield of about 70%.

  (thin layer chromatography, infrared spectroscopy

  red and NMR, amine determination, elemental analysis and electrical conductivity) shows that it is the amide of formula IV (melting point: 124-127 ° C):

/ CH 2 -NH 2

2 2 O

> \ C <-NH "CH 2 \ '__ /

\ /, '\ /

I (Iv)

* CNH-CH 2- /

CH 2 -NH 2

  The product obtained does not contain any saline compounds, such as

as carboxylates of amines.

  A mixture of 100 parts of the compound (IV) with 54 parts of tetraglycidylated methylenedianiline and 54 parts of triglycidylated p-aminophenol showed good storage stability at room temperature during

4 months.

EXAMPLE 2

  By the method described in J Chem Soc 1945,

  pp. 625-628, bis (p-aminocyclohexyl) is reacted.

  methane with phthalimide in an aqueous medium in order to obtain bis (paminocyclohexyl) methane phthalamide, that is to say

  NN'-bis (4-aminocyclohexylmethyl) -4 cyclohexyl 17-

  phthalamide: for this we add in 10 minutes, at

  At room temperature, an aqueous emulsion of the amine, which was prepared by vigorous stirring, finely ground phthalimide in an amount of 1 mole per 2.4 moles of the amine, the mixture is stirred for an additional 40 minutes. It is filtered off in a separatory funnel and extracted with chloroform. The extract is dried over magnesium sulphate, filtered and the chloroform is removed. After that, the product is washed with hexane and then with the oxide. anhydrous diethyl; the washing solvent residues are eliminated

  by distillation in the vacuum oven.

  A glassy product with a yield of

  28%, product which has a melting range of 75 to 90 C.

  The analysis (NMR spectrum) shows that it is a product resulting from the reaction of 2 moles of the amine with 1 mole

of the imide.

EXAMPLE 3

  By operating in the same way as in Example 2, we do

  react phthalimide with bis (aminomethyl) -1,3 cyclohexane.

  A glassy product having a melting range of 54 to 66 ° C. is obtained. According to the IR and NMR spectra, this is the diamide formed by the union of 1 phthalic acid molecule with

2 molecules of the amine.

EXAMPLE 4

  By operating in the same manner as in Example 2,

  reacts phthalimide with 1,2-diamino cyclohexane.

  A slightly brownish product is obtained which has a

  melting range from 69 to 75 C The IR and NMR spectra show that it is the diamide resulting from the union of molecule

  of phthalic acid with 2 molecules of the amine.

EXAMPLE 5

  The same product as in Example 4 is obtained by

  To react 2 moles of 1,2-diamino cyclohexane with 1 mole

  phthalic anhydride for 45 minutes at 125 C without

Solvent.

  By operating as described in the preceding examples, the other amines which have been mentioned above can also be reacted with the corresponding imides or acid anhydrides in order to obtain compounds which comply with the above requirements.

to the invention.

  EXAMPLES relating to the applications: One submits to a differential termo-analysis (DSC =

  differential scanning calorimetry) a homogeneous paste

  of 100 parts of the compound of Example 1, as hardener, 54 parts of tetra-glycidylated methylene dianiline (Araldite MY 720) and 54 parts of triglydicylated p-amino phenol (Araldit 0510). a reaction heat of 293.16 kJ per mole is evolved at 114 ° C. This value shows that the reaction is substantially complete below 150 ° C. The mixture is kept at room temperature and its storage stability is examined. at regular time intervals It is found that for 11 weeks the reaction heat undergoes only an insignificant decrease (from 293 kJ to 279 kJ / molej or 96.5% of the initial value) After 16 weeks it is 84% more than the starting value At the end of the month the color and fluidity are almost unchanged. All reviews show that storage stability at the

  room temperature is 4 months.

  With the mixture, discs 2.5 cm in diameter are produced by molding in a press for 30 minutes at C under a pressure of 412 M Pa. After hardening

  complementary to 150 C the temperature of

  It is found to be 120-130 C (DSC method) The absorption of water in an atmosphere has a relative humidity of 95% and a temperature of

of 71 C is 5.5%.

  Analogous values are obtained using the compounds of Examples 2 to 5 and mixtures of epoxy resins according to this example, or epoxy resins.

  based on bisphenol A or cyclic epoxy resins

aliphatic.

Claims (7)

  1. Compounds of formula I 0 O He He H 2 NR HN C Y C NU R NH 2 (I)   in which Y represents an aromatic radical, cyclo   aliphatic or aliphatic which carries the two carbon groups represented on the formula in positions close to each other, and R represents a radical   arylene, aralkylene, cycloalkylene or cycloalkylalkylene.   Compounds according to claim 1 wherein Y in formula I represents the radical of phthalic acid, tetrahydrophthalic acid,   hexahydro-phthalic acid, succinic acid, dodec   cyl-succinic or maleic acid.   3. Compounds according to claim 1, in which R, in formula I, represents an m-xylylene, cyclohexylene-1,2 or 1,4-radical, methane-bis (p-cyclohexylene), cyclohexane-bis-methylene -1.3 or -1.4, methane-bis (methyl-3   1,4-cyclohexylene) or 3,5,5-trimethyl-3-methylene cyclohexyl.   4. Compounds according to claim I in which   R represents a radical m or p-phenylene, methane-p, p'-   diphenyl, sulfonyl-bis- (p-phenyl) or (p-phenylene) -1-trimethyl- 1,3,3 indanyl-f 6.   5. Compounds according to claims 2 and 3 or 2 and 4.   6 -Process for the preparation of compounds of formula I   according to any one of claims 1 to 5,   characterized in that a compound of formula I Ia or I Ib is reacted with: C = O C = O   co Y, X Y X (I Ib) with a compound of formula III H 2 N R NH 2 (III)   formulas in which Y and R have the meanings   data in claims 1 to 5.   1-0 7. Curable mixtures characterized in that   contain a compound according to any of the claims   cations 1 to 5 and a polyepoxide compound. f