DEC0009837MA - - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

Registration date: August 20, 1954. Advertised on July 19, 1956

GERMAN PATENT OFFICE

It is known for curing polyepoxy compounds to use a polycarboxylic anhydride. Here are under polyepoxy compounds Condensation products understood as they are in a known manner by the implementation of polyvalent, in particular polynuclear phenols, or of aliphatic polyhydric alcohols with epihalohydrins or dihalohydrins can be obtained in an alkaline medium. Used preferably the polyepoxy compounds used are those from 4,4'-dioxydiphenyldimethylmethane; here are products with a content of 4 or more gram equivalents Epoxy group per kg of polyepoxy compound is particularly suitable. . .

In the practical production of casting, coating and dipping compounds, adhesives and impregnating agents, fillers based on Polyepoxide compounds, it has often proven to be very disadvantageous that the polyepoxide-hardener mixtures have too short a service life, especially when the mixtures are at high Temperatures are used at which, as is known, the hardening process occurs more rapidly and the. Viscosity increases faster than at lower temperatures.

It is also desirable to use a homogeneous mixture of polyamide and hardener. to be able to work. Attempts have already been made to obtain a homogeneous distribution at low temperatures in that toluene, benzene or another solvent is added to the anhydride and the polyepoxide compound. However, this measure is inexpedient for those cases in which the presence of solvents is undesirable. Working without a solution

609 550/501

C 9837 IVb / 39b

medium, ζ. B. in the production of castings, is not possible at any temperature because the temperature at which a homogeneous distribution is guaranteed, primarily on the properties depends on the polycarboxylic anhydride used. It has now been shown that the service life a polyepoxide hardener mixture primarily depends on the saturation temperature of the polycarboxylic acid anhydride used depends. The saturation temperature of an anhydride is understood to be the lowest temperature at which a certain Amount of anhydride in a certain amount of polyepoxy compound in homogeneous distribution in solution remains. High-melting polycarboxylic acid anhydrides usually have a high saturation temperature, which is why they only allow a short service life. It has now been found that one can use the duration of polyepoxide-hardener mixtures in the presence of high-melting polycarboxylic acid anhydrides can extend by using mixtures of anhydrides, especially mixtures of high and low-melting polycarboxylic anhydrides, unisetzt.

The invention is a process for curing polyepoxy compounds with polycarboxylic acid anhydrides, which is characterized in that the polyepoxy compounds are reacted with a mixture of polycarboxylic acid anhydrides in an amount of 0.7 to ι gram equivalent anhydride group to 1 gram equivalent epoxy group, ^{1 being} the anhydride group at least one high melting point Contains polycarboxylic anhydride such as phthalic anhydride.

High-melting polycarboxylic anhydrides in the sense of the present process are those that Melt well above 100 ° C, such as B. phthalic anhydride, Tetrachlorophthalic anhydride, hexa-. chlorine - endomethylenetetrahydrophthalic anhydride, Succinic anhydride, anhydrides of polybasic aromatic carboxylic acids, addition products of Maleic anhydride on diene compounds, such as methyl abietate, dipentene or wood oil.

. Mixtures of these high-melting anhydrides with one another and / or with lower

melting polycarboxylic anhydrides, e.g. B. maleic anhydride, or hydrogenated phthalic anhydrides, such as tetrahydro- or hexahydrophthalic anhydrides can be used. These mixtures can be composed according to any mixing ratio. It can e.g. B. Mixtures are used which are composed so that the melting point of the mixtures either below the melting point of the second highest melting component or below the lowest melting the component cherishes.

Finally, z. B. the eutectic mixtures can also be used.

It has been shown that good mechanical properties of the cured product are obtained, if 0.7 to 1 gram equivalent of anhydride group to ι gram equivalent of epoxy group, preferably 0.8 to 0.9 gram equivalent anhydride group to ι gram equivalent epoxy group, implemented will.

Known pigments, coloring agents, can also be added to the polyepoxide-hardener mixture or its components Add substances, accelerators and fillers.

In the examples below, percentages are given Percentages by weight, parts by weight.

The polyepoxy compounds used in the examples were prepared as follows: 1 mole of 4,4'-dioxydiphenyl-dimethylmethane was mixed with about 6 moles of epichlorohydrin reacted in the presence of aqueous sodium hydroxide solution, and the resultant Product was then washed out and dried. Thereby were polyepoxy compounds obtained with an epoxy content between 4 and 5.3 gram equivalents of epoxy group per kg.

example 1

To prepare the ready-to-use mixture, 0.9 anhydride gram equivalents of the following Anhydride mixtures at about their melting temperature in 1 gram equivalent of one Polyepoxy compound dissolved, which contains 4.6 gram equivalent epoxy group per kg, and on the Saturation temperature cooled.

■ ".." (phthalic anhydride in% ....

.Harter- 1 _cis ^ 4_ _{Tetrahydrophthalic acid} _

composition,,.,. _n ,

^ö I anhydnd in ° / ₀

Melting point or solidification point of the anhydride or the anhydride mixture in ° C

. Saturation temperature of the anhydride or the anhydride mixture in ⁰ C

Initial viscosity of the anhydride-polyepoxide ί at ⁰ C mixture {in cP

",,,, F.." at ° C

Service life of,. ■ _π . ",,

TT- χ τ. τ ■ j _M. , ■ <up to 1500 cP m hrs.

Hard polyepoxide mixture,. · ° _π ■. _c ^{,, J} ^ ^{J b} [up to 3000 cP m hrs.

* Eutectic mixture.

Attempt no. 3 I. 2 55.0 100.0 80.0 -45, o O 20.0 94.5 128.0 115.0 75, o 105.0 90.0 75, o
50.0 105.0
20.0 90.0
35, o 75, o
32
35 105.0
5 ¹ / *
5 ¹ U 90.0
! 4
15V2

4 *

35.0
65.0

75.5

60.0

60.0
90.0

60.0

55
72

550/501

C 9837 IVb / 39b

The ones at 100 to 160 °, ζ. Β. Products cured with these anhydride mixtures for 24 to 36 hours at 120 ° or 10 to 14 hours at 140 ° have the same excellent mechanical and electrical properties as those which have been cured only with a polycarboxylic acid anhydride. The curing time and / or curing temperature can be reduced by adding small amounts of accelerators, for example basic compounds. Are 3-diaminopropane added to the above mixture 0.25 to ι% triethylenetetramine or N, N-Dimethyli, so at 120 ° can be cured in about 36 to 48 hours already in about 1 to 3 hours or at 70 ^0th Similar effects are achieved if the carboxylic acid anhydride mixture or a part thereof is heated prior to addition with the amine.

The useful life of the polyepoxide-hardener mixtures can be extended by adding any amount of a newly prepared anhydride-polyepoxide mixture to the remaining mixture after a certain period of use. If in the above-mentioned experiment No. 4 a consumption of 50 ° / _{0 is} assumed after 24 hours and the amount used is then replaced by a newly prepared anhydride mixture-polyepoxide mixture, the following results are achieved:

viscosity 3 at 60 ° in cP after * 4 850 850 I. 5 9 Days 280 280 before replacing the ver 700 needed amount 430 ' 750 after replacing the ver 260 needed amount 220 270

It is thus possible. to be able to work for many days while maintaining a relatively narrow viscosity range. 80

Example 2

Instead of the poly 85 described in Example 1 epoxy compound is one with an epoxy group content of 4.75 gram equivalents "per kg used.

Phthalic anhydride in ° / ₀ ;. ice Δ "tetrahydrophthalic anhydride in ° / ₀ .

ice hexahydrophthalic acid

Hardener composition

anhydride in%.

Melting point or solidification point of the anhydride or the anhydride mixture in ⁰ C.

Saturation temperature of the anhydride or the anhydride mixture in ⁰ C

Initial viscosity of ί at ° C

Anhydride-polyepoxide mixture \ in cP

Service life of,. ■ _n . _ · ,.

TT-. . t>! ·, "■ r. < up to 1500 cP in hours

Hard polyepoxide mixture,. ^J - ^. ",,

^{J r J b} { up to 3000 cP m hrs.

* Eutectic mixture.

Attempt no.
1.2 * I.3

100.0
O
O

128.0

105.0
105.0

20.0
105.0

6V4
6V2

35, o

65.0

75.5

60.0

60.0
80.0

60.0

24.0 45, o 31.0

60.0

45, o

45, o 250.0

45, o

74 118

Example 3

From an anhydride mixture consisting of 25 parts of tetrachlorophthalic anhydride and 75 parts of phthalic anhydride, are dissolved at about 120 ⁰ 0.85 anhydride equivalents in grams ι gram equivalent of a Polyepoxydverbindung with a Epoxydgruppengehalt of 4.9 gram equivalents per kg.

The anhydride mixture has a freezing point

of 120 °, and the polyepoxide-hardener mixture has a service life of 3 hours at 100 ° up to a viscosity of 1500 cP. The use of tetrachlorophthalic anhydride alone proves to be unsuitable. As a result of its very high melting point of about 243 ⁰ and the resulting very high melting temperature, the polyepoxide-tetrachlorophthalic anhydride mixture is largely hardened before the anhydride is homogeneously dissolved in the polyepoxide compound 115.

Example 4

0.9 anhydride gram equivalents of the following lap Anhydride mixtures are approximately at their melting temperature in ι gram equivalent of a polyepoxy compound dissolved and cooled to saturation temperature. The epoxy group content that was used Polyepoxy compound is 4.75 grams - 125 equivalents per kg.

609 550/501

C 9837 IVb 139 b

. C succinic anhydride in% .... hardener J phthalic anhydride in ° / ₀ ..... composition 1 cis Δ ⁴ -Tetrahydrophthalic acid-

I anhydride in ° / ₀

Melting point or solidification point of the anhydride or the anhydride mixture in ⁰ C.

Saturation temperature of the anhydride or the anhydride mixture in ° C

Initial viscosity of ί at ° -C

Anhydride-polyepoxide mixture j in cP

Service life of the. j. at ° C

Hardener-polyepoxide mixture \ up to 1500 cP in hours

[up to 3000 cP in hours * Eutectic mixture.

Attempt no. 2 O 3 4 * ■ I I. 100 ' 68 51 IOO O 32 49 O 128 0 0 O. 105 98 88 115 ' 105 86 76 IOO 20th 86. 76 ioo IO5 35 50 30th 6V4 86 76. IOO 26th 38 17th .29 47 I7 ³ / *

22nd

22 56

68

60

60 80

60 50

81

Claims (4)

PATENT CLAIMS: 1. A method for curing polyepoxy compounds with polycarboxylic anhydrides, thereby characterized in that the polyepoxy compounds with a mixture of polycarboxylic anhydrides are reacted in an amount of 0.7 to 1 gram equivalent of anhydride group to 1 gram equivalent of epoxy group, wherein the anhydride group is at least one high-melting polycarboxylic acid anhydride, such as phthalic anhydride, contains. , 2. The method according to claim 1, characterized in that that it is reacted with a polycarboxylic anhydride mixture that is below the second highest melting point or below the lowest melting anhydride component melts. 3. The method according to claim 1 and 2, characterized in that with a eutectic mixture is implemented by polycarboxylic anhydrides. 4. The method according to claim 1 to '3, characterized in that with hydrogenated polycarboxylic ^{anhydrides, such as 1} tetrahydrophthalic anhydride, or with. a mixture of tetra- ■ hydrophthalic anhydride and hexahydrophthalic anhydride is implemented as low-melting components. . © 609 560/501 7.56