CS265857B1 - Plasticizer accelerating reaction of aliphatic amines and epoxides - Google Patents

Description

The present invention relates to an accelerating plasticizer for the reaction of aliphatic amines with epoxides or liquid epoxy elastomers with a solution of bisphenol A in a mixture of allyl derivatives of bisphenol A with a plasticizing effect.

For successful curing of epoxy resins with aliphatic polyamines, it is recommended to operate at a minimum temperature of 18 ° C. At lower temperatures, curing accelerators are required, although the reaction of the epoxy group with both the primary and secondary amine hydrogen forms a secondary hydroxyl group which also accelerates. At the same time, any acceleration of the cure is associated with a reduction in the pot life. If a slower curing agent such as amine adducts or amino amides is used, there may be a need to accelerate curing even at room temperature. This results in higher molecular weight and lower concentrations of primary amine groups. Excessive acceleration can lead to inhomogeneity of the cured material and greater internal stress in it.

Hydrogen donors, such as alcohols, phenols, acids or water, usually have an accelerating effect. However, they usually have too low boiling points and therefore cannot be used in larger quantities or have a higher molecular weight, but are then solid

265 857 and must be dissolved for dosing, eg bisphenol A.

A practical accelerator must have good processability, dosability, compatibility with the resins and no adverse effects on the properties of the cured materials. For example, salicylic acid requires the absence of iron. For curing with aliphatic polamines at room temperature, the usual accelerators are triethanolamine, benzoic acid and salicylic acid and cresol. Phenols are also effective at + 5 ° C, alcohols no longer. Bisphenol A, which is one of the two main raw materials for the production of epoxy resins, is also effective. However, it is a solid at room temperature. Also described is acceleration due to the mono-2,3-dihydroxypropyl ether-monoglycidyl ether of bisphenol A, which can be obtained by hydrolyzing the bisglycidyl ether of bisphenol A in an alkaline medium. Of all the phenols $ e, most attention was given to m-cresol, which has an unpleasant odor and is washed away with water. In this, alkylphenols are better, but they have lower efficiency and need to be used in larger amounts. Larger amounts can be used when the accelerator has a plasticizing effect, since there is no sharp deterioration in particular of the mechanical properties. The efficiency increases with the acidity of the phenolic OH group. However, strong acids do not accelerate, but rather form amine salts. Sometimes pyrrolidine complexes with koynes, amides, imides, lactic acid, hydroxyalkylated polyamines, sulfamides, sulfic acids, thiocyanic acid salts, aminopropyl derivatives of polyaxialkylenepolyamines, aniline condensates with formaldehyde, suitones, tetrahydrothiodiazine or tetrahydrothiadiazine-2-thiourea derivatives, , piperazine, thiophosphates, phenol-formaldehyde condensates, tris- (dimethylaminomethyl) -phenol, triphenylphosphite and the like.

We have now found that a number of the above problems of accelerating the hardening of epoxy resins or liquid epoxy elastomers by aliphatic polyamines are solved by using a plasticizing accelerator consisting of a mass of

265 857 to 50 parts of bisphenols A, up to 85 parts of bisphenol A diallyl ether, up to 25 parts of bisphenol A monoalyl ethers, up to 10 parts of allylated bisphenol A monoallyl ether and up to 18 parts of allylbisphenol A in amounts of 0.5 to 35 parts per 100 parts of epoxide.

The accelerating plasticizers of the invention are prepared by mixing the individual components (sometimes elevated temperatures, e.g., 70 ° may be required) or as products of a suitably guided reaction of allyl chloride with bisphenol A. Other bispheaols, e.g. bisphenol P, may be used io, p- and o, o-isomers. Sometimes it is advantageous to add an inert plasticizer or diluent to the accelerator for better processability.

New accelerating plasticizers are usually yellow to brown liquids with a viscosity of 0.3 to 10 Pa.s at 25 ° C, do not smell, due to the higher average molar mass, they can be used in larger quantities than the hitherto used accelerators; Significantly lower toxicological hazards for workers, do not wash out with water and reduce the viscosity of the epoxy resin or liquid elastomer used. Their efficacy is comparable to that of a kres-cresoler. In addition, they increase resistance to thermo-oxidative aging. With the amount used, both acceleration and plastification increase. They can also be used for modified epoxy resins. When modifying unsaturated organic acid esters whose double bonds react in addition to aliphatic polyamines, the corresponding amount of aliphatic polyamines must be increased accordingly. These are, for example, diethylenetriamine, dipropylenetriamine, tetraethylenepentaraine, trimethylhexamethylenediamine, pentamethylenediamine, their adducts, modifications and mixtures thereof. Both polyamines, such as isophorone diamine, have been shown to accelerate and plasify. They are generally used in an amount of 90 to 160% of the theory based on the epoxy group content.

The epoxy resins used are usually of the dian type having an average molecular weight of 300 to 600 and may also contain fillers, pigments and additives regulating mechanical and

265 857 technological properties. Liquid epoxy elastomers have a molecular weight of 500 to 1000. These are products based on epoxy resins or compounds having an average molecular weight of 170 to 500 and polymeric fatty acids or carboxylic oligomers having an average molecular weight of 500 to 1500.

Example 1

Four types of accelerating plasticizers were used. Their

probable composition in mass. % Yippee this: type AND (B) 0 D bisphenol A 7 15 Dec 25 40 bisphenol diallyl ether 70 45 40 35 bisphenol monoallyl ether 10 20 May 18 15 Dec allylated monoallyl ether bis- phenol A 8 5 4 3 allylbisphenol A 5 15 Dec 13 7 The accelerating effect was monitored u reaction epo xid resin

ce of average molecular weight 385 with dipropylene triamine at 23 ° C. 1.0 g resin, 2.8 g test substance and 19 g (100% of theory) dipropylene triamine were successively weighed into a PVC crucible. Immediately after weighing, the mixture was homogenized by mixing on a 5 cm high wooden support. The temperature was read by a 1 ° C thermometer. The temperature increase over 15 minutes, the OH content of the test substance in raol / 100 g and the ultimate tensile strength T (MPa) and tensile strength t (%) determined 28 days after casting are given in the table:

test substance _-1 ° C OH T t - ——— • and »- ——— ——— —— - .9 - 37 3 bisphenol diallyl ether 9 0.010 38 3 type A 11 0.161 50 4 type B 13 0.335 50 4 type C 13.5 0.397 42 3 type D L ¹ !., 0.468 30 3

265 857

Example 2

Following the procedure of Example 1, compositions K / 22.5 g of type B accelerator + 127.5 g of average molecular weight epoxy resin 385 + 13.5 g of diethylenetriamine / and L / 150 g of the same resin + 16.4 g were prepared and cast. diethylenetriamine. Composition K had a temperature rise of 13 ° C in 5 minutes, composition L only 3 ° C. After 28 days, the ultimate tensile strength and ductility were found to be 58 MPa and 8% for K, and 36% for L and 4%, respectively.

Example 3

Compositions K and L of Example 2 were prepared from raw materials tempered to 12 ° C and after 5 minutes of stirring at 23 ° C were placed in rooms at 23, 10 and 3 ° C. , ^ 22222í22-—

10 3

130 240

2 £ ......... ,, 240 ,,,, 7 ^ 2®,

Example 4

Composition M (140 g of an average molecular weight of 392 + 2.8 g of accelerator + 19 g of dipropylene triamine) was monitored at 25 ° C. After 10 minutes, temperature increases were observed and after 28 days mechanical properties:

accelerator + ° C T t thrust. product

type B 11.5 83 8 664 triethanolamine 11 63 6 378 tricresol 12 77 2.5 193

Example 5

The effect of the amount of type C accelerator was investigated for the compositions N (32 g dibutyl phthalate 113 g epoxy resin with medium

265 857 molecular weight 588 + 0 or 5 → 8 or 29 or 40 g type C + 8.4 g diethylenetriamine). The last line states the use

160% of theory hardeners: Ue-Sx-1 (TM). T, MPa 0 4 37 5 . 5.8 9 . 31 6 29 15 Dec 6 8 40 19 Dec 4 17 5.8 8 32 15 Dec

Example 6

The effect of the accelerator on epoxide rubber formation is shown by composition P (140 g liquid epoxy elastomer with an average molecular weight of 800 + 14 g trimethylhexamethylenediamine ΊΟ or 2.8 g type C. Observed values are g accelerator + ° C / 10 minutes T (MPa) t (%)

7 3 60

2.8 9 3.5 65

Example 7

The effect of thermo-oxidative aging (4 days, 125 ° C) was verified for composition R (120 g epoxy resins © mean molecular weight 588 + 30 g plasticizer + 8.8 g diethylenetriamine);

Pláštifikátor + 10 ° C / 10 minutes * ο at dihutylphthalate 6 37 6 9 2 3.3 benzyl alcohol 19 Dec 43 5 3 2 10.4 bisphenol diallyl ether 6 64 5 44 4 1.3 type B 14.5 / 5 minutes 35 5 26 3 0.8

Example 8

When curing 140 g of epoxide resin having a mean molecular weight of 385/19 g of dipropylene triamine, 31 g of a solution were added.

265,857 weight composition 9 parts of bisphenol A + 26 parts of dibutyl phthalate + 65 parts of bisphenol A diallyl ether A. The temperature increase over 10 minutes was 11 ° C. After 28 days, the cured mass had a tensile strength of 64 MPa and a ductility of 6 after 4 days at 125 ° C of only 53 MPa and 4%. If monoallyl ether of bisphenol A is used instead of dibutyl phthalate, the temperature rise is 14 ° C in 5 minutes and the cured mass has a tensile strength of 77 MPa and a ductility of 5% after 28 days.

Claims (3)

Accelerating plasticizer for the reaction of aliphatic amines with epoxides of 300 to 600 average molecular weight and liquid epoxy elastomers of 500 to 1000 average molecular weight (characterized in that it contains 3 to 5% by weight of bisphenol A), 25 to 85 parts of bisphenol A diallyl ether, 5 to 25 parts of bisphenol A monoallyl ether, 2 to 10 parts of allylated bisphenol monoallyl ether; and a 3 to 18 parts of allyl bisphenols A. Printed by Moravian Printing Works, Center 100, Studentská tř.5, OLOMOUC