DE1099731B - Heat-hardenable molding or adhesive compound - Google Patents

Description

GERMAN

The invention relates to thermosetting molding compositions or adhesives based on a liquid or fusible glycidyl ether or ester.

Resin-like condensation products, which by reaction between an epoxy compound and a Dianhydride of a polybasic carboxylic acid, ζ. Β. Pyromellitic dianhydride obtained are known. However, no catalyst is used in this known reaction.

According to the known method from a gm glycidyl ether However, resins obtained or esters and pyromellitic dianhydride are unusable in many respects. Once the pyromellitic dianhydride does not dissolve sufficiently in the glycidyl ether or ester, so that the end products obtained are cloudy castings and, on the other hand, the dianhydride and the glycidyl compound then react not properly with one another, so that the products obtained have heat resistance values below 80 ° C exhibit.

It has now been found that resin products with excellent properties can be obtained from the components mentioned, which in the cured state have heat ^{resistance of over 100 °} C. and give completely clear castings if a curing catalyst with at least one primary or secondary amino group is present.

The invention thus consists in thermosetting molding or adhesive compositions based on a liquid or fusible glycidyl ethers or esters which, apart from an epoxy group, have no reactive groups have and have a molecular weight below 500, and pyromellitic dianhydrides, which additionally have a Curing catalyst with at least one amino group bearing active hydrogen atoms and with one Contain molecular weight below 500, the proportion of pyromellitic dianhydride being such that encounter 0.5 to 1.05 anhydride groups for each epoxy group. From these masses one then gets through easy hardening at elevated temperature valuable synthetic resins.

If less than 0.5 anhydride groups meet each epoxy group, the heat resistance will decrease of the cured resin product decreased. If there is more than one anhydride group for each epoxy group, then so the anhydride is difficult to dissolve in the epoxy.

Suitable catalysts include dicyandiamide, diisopropylamine, ethylenediamine, cyclohexylamine, tert. Butylamine, m-xylylenediamine, aniline, piperidine, Methylenedianiline and others known to the person skilled in the art and falling under the above definition Links. The catalysts are only required in very small amounts, with amounts between 0.01 and 2.0 parts per 100 parts of the glycidyl

Thermosetting molding or adhesive

Applicant:

EI du Pont de Nemours and Company,
Wilmington, Del. (V. St. A.)

Representative: Dipl.-Ing. E. Prince

and Dr. rer. nat. G. Hauser, patent attorneys,

Munich-Pasing, Bodenseestr. 3 a

Claimed priority:
V. St. v. America December 31, 1957

Thomas Joseph Hyde, Woodbury, NJ (V. St. A.),
has been named as the inventor

ether or ester gives good results. If less than 0.01 part of catalyst is used, this is decreased the rate of cure increases, and if more than 2.0 parts of the catalyst is used, the will gel Mixes prematurely. The catalyst is conveniently used in an amount between 0.08 and 2.0 parts per 100 parts of the glycidyl ether or ester is present.

The time required for the compositions to cure can range from a few minutes to a few hours and depends primarily on the curing temperature, but also on the catalyst used and other factors. The curing temperature must in each case sufficient to achieve a substantial crosslinking and is generally between 80 and 180 ⁰ C. Below 8O ⁰ C, cure times are too long, and above 18O ⁰ C, the mixture begins to char. The optimum cure schedule (ratio of curing time to cure temperature) was found to be about one hour to about 18 hours at 18O ⁰ C. However, these values can vary considerably, depending on the desired properties in the cured product and other factors.

The following examples illustrate specific embodiments of the production and curing of the compositions according to the invention. In the examples, "parts" mean parts by weight.

The heat resistance of the cured resin compositions was determined by the ASTM method D 648-45 T, described in ASTM standards, 1955 edition, part 6, pages 296 to 299.

109 510/46 +

example 1

0.1 parts of dicyandiamide as a catalyst were dissolved in 25 parts of glycidyl p-toluate by heating the mixture to 140 ⁰ C dissolved. The solution was then cooled to 60 ⁰ C, followed by addition of 14 parts of the dianhydride of pyromellitic acid. This combination resulted in one anhydride group for each epoxy group. The mixture was stirred for 10 minutes at 80 ⁰ C and then poured into a preheated to 180 ⁰ C shape, after which was cured for 2 hours at 180 ⁰ C. The obtained resin composition, cured had a heat deflection temperature of 150 ⁰ C.

Example 2

0.2 parts of dicyandiamide as a catalyst were dissolved in 50 parts of phenylglycidyl ether at 125.degree. Then 30 parts of the dianhydride of pyromellitic acid were added. This combination gave 0.85 anhydride groups for each epoxy group. The mixture was heated until the clearing point (165 ° C.) was reached, ie until the slurry formed a clear solution. When curing for 22 hours at 180 ⁰ C the mixture gives a resin product having a heat resistance of 118 ° C. A similar mixture cured at 140 ° C for 20 hours gave a resin product with a heat resistance of 113 ° C.

Example 3

0.2 parts of N-oxypropylethylenediamine were mixed with 50 parts of phenylglycidyl ether at room temperature. Was then added 30 parts of the dianhydride of pyromellitic acid (0.85 anhydride groups to epoxide Ede j) is added and the mixture was heated until reaching the clearing point (180 ⁰ C). Then the mixture was poured into a preheated to 180 ° C mold and cured 17 hours at 180 ⁰ C of 3. The heat resistance of the cured resin product was 121 ^° C.

Example 4

The procedure of Example 3 was repeated, but instead of the N-oxypropylethylenediamine, 0.2 parts tert. Butylamine were used as a catalyst. · The mixture was heated until reaching the clearing point (175 ° C) and then cured for 18 hours at 180 ⁰ C. A hardened resin product with a heat resistance of 114 ° C. was obtained.

The resin products obtained in all examples not only had the specified good heat resistance, but also excellent toughness, flexural strength and chemical resistance. the According to the invention used glycidyl ethers and esters have compared to the di- and polyepoxides Advantage of more economical production. They are also less viscous and therefore easier to put into compositions to handle.

Claims (1)

Claim: Thermosetting molding or adhesive based on a liquid or meltable glycidyl ether or esters, which apart from an epoxy group have no reactive groups and a Have molecular weight below 500, and pyromellitic dianhydride, additionally containing one Curing catalyst with at least one amino group bearing active hydrogen atoms and with a molecular weight below 500, the proportion of the pyromellitic dianhydride being dimensioned so that 0.5 to 1.05 anhydride groups meet for each epoxy group. Considered publications:
German patent application D 7193 IVb / 39c (published on September 4, 1952). © 109 510/464 2.61