CN108884300A - Curable poured with epoxy resin material - Google Patents

Abstract

Curable poured with epoxy resin material known to morning, containing epoxy resin, the curing agent for the epoxy resin, aluminium oxide and the specific elasticity for realizing the casting material additive.In the case where poured with epoxy resin material of the invention, the processing viscosity and impregnability of the casting material are improved.Arranged according to the present invention, the aluminium oxide includes two kinds of particles fraction, wherein the first particle fraction is greater than 80%, preferably 85 to 95% with filler, particularly preferred 89% to 91% mass content simultaneously has the particle for being averagely greater than the second particle fraction.

Description

Curable Epoxy Casting Compounds

current technology

The invention relates to a curable epoxy resin casting compound of the type according to the main claim.

A curable epoxy resin casting composition is already known from EP 1 352 026 B1, which contains an epoxy resin, a curing agent for the epoxy resin, aluminum oxide as filler and additives for achieving a specific elasticity of the casting composition .

Furthermore, electric machines are known which have electrical windings which are impregnated and surrounded by a single epoxy resin mass. However, the epoxy resin casting compounds generally have a low thermal conductivity. It is also known that the capillaries between the copper wires are filled with a special impregnation resin in a first manufacturing step and that the electrical windings are surrounded in a second manufacturing step by a further hard encapsulating material, but this encapsulating material has Low damping properties.

Advantages of the invention

In contrast to this, the curable epoxy resin casting compound according to the invention has the advantage of improving the processing viscosity and the impregnation capacity of the casting compound, so that the casting compound can be more compact due to its low viscosity. Easily fills and completely fills cavities between wires of electrical windings. This is achieved according to the invention in that the aluminum oxide comprises two particle fractions, wherein the first particle fraction has a mass content of more than 80%, preferably 85 to 95%, particularly preferably 89% to 91%, of the filler and have particles that are on average larger than the second particle fraction. The casting compound according to the invention enables impregnation between the wires and wrapping around the electrical winding by using only a single material in a single production step.

Advantageous developments and improvements of the curable epoxy resin casting compound indicated in the main claim are possible by means of the measures listed in the subclaims.

It is particularly advantageous if the aluminum oxide has a content of more than 70% of the casting compound, since good thermal conductivity of the epoxy resin casting compound is achieved in this way. When using the particle size distribution claimed according to the invention of the two particle fractions, a low processing viscosity and good impregnation properties of the epoxy resin casting compound are achieved despite a relatively high filling content of more than 70%.

It is also advantageous if the aluminum oxide comprises substantially spherical particles. In other words, even spherical alumina is used as a filler. This has the advantage that the processing viscosity of the casting resin is further reduced, so that it can also flow into narrow cracks and cavities and fill them completely.

It is very advantageous if the additive is made of a polyether polyol-based acid (sauren) ester, since in this way the required elasticity of the casting composition is maintained over a certain service life, so that an aging-resistant casting resin is achieved. Furthermore, good acoustic damping properties and good thermal shock resistance are achieved by these additives.

Description of the embodiment

The curable epoxy resin casting compound according to the invention contains an epoxy resin, a curing agent for the epoxy resin, spherical alumina and additives for achieving a specific elasticity of the casting compound. This additive is also known as a toughener and is made from acid esters based on polyether polyols. The epoxy resin casting compositions according to the invention can be used as electrical insulating materials for electrical or electronic components, in particular for insulating electrical windings of electric machines. When used in an electric motor, the potting compound can also be designed to dissipate heat from the electrical winding and to dampen acoustic vibrations or operating noises generated in the electric motor. In the case of an electrical winding of an electrical machine, the casting compound completely fills the cavities or capillaries between the wires or conductors of this electrical winding. Furthermore, the potting compound forms a coating around the electrical winding, in particular in the region of the winding head of the electrical machine. The coating makes the electrical winding resistant to liquid media, such as oil.

It is provided according to the invention that the alumina comprises two particle fractions, wherein the first particle fraction has a filler, ie a mass content of more than 80%, preferably 85 to 95%, particularly preferably 89% to 91%, of the alumina, and have particles that are on average larger than the second particle fraction.

The aluminum oxide has a mass content of more than 70%, for example 74% to 76%, especially 75%, of the epoxy resin casting compound.

The first particle fraction has a mass content of 80 to 95% of alumina and the second particle fraction has a mass content of 5 to 20% of alumina.

The particle size distribution of the two particle fractions is described by several parameters as follows. For the first particle fraction, the 10% percentile is between 5 μm and 15 μm, especially 10 μm. For the second particle fraction, the 90% percentile is between 2 μm and 7 μm, especially 4.5 μm.

For the first particle fraction, the 10% percentile is 5 μm to 15 μm, especially 10 μm, the 25% percentile is 15 μm to 25 μm, especially 20 μm, the median is 25 μm to 35 μm, especially 30 μm, the 75th percentile is 35 μm to 45 μm, especially 40 μm, and the 90th percentile is 45 μm to 55 μm, especially 50 μm.

For the second particle fraction, the 10% percentile is 0.1 μm to 1 μm, especially 0.5 μm, the 25th percentile is 0.5 μm to 1.5 μm, especially 1 μm, the median is 1 μm to 2 μm, especially 1.5 μm, 75% percentile is 1 μm to 4 μm, especially 2.5 μm, 90% percentile is 2 μm to 7 μm, especially 4.5 μm.

During the preparation of the epoxy resin casting compound, the two particle fractions of the aluminum oxide are mixed into the casting compound with the other components of the mixture. The two particle fractions are here homogeneously dispersed in the casting composition. The particle size distribution resulting from the mixture of the two particle fractions corresponds to the sum of the two respective particle size distributions of the two particle fractions.

Claims (11)

1. Curable epoxy resin casting material, which contains a) epoxy resin, b) curing agents for epoxy resins, c) alumina as filler, d) an additive for achieving a specific elasticity of the casting compound, characterized in that, The alumina comprises two particle fractions, wherein the first particle fraction has a mass content of greater than 80%, preferably 85 to 95%, particularly preferably 89% to 91%, of the filler and has an average greater than the second particle fraction Particles. 2. The epoxy resin casting composition according to claim 1, characterized in that the aluminum oxide has a mass content of more than 70% of the casting composition. 3. The epoxy resin casting composition according to claim 1, characterized in that the first particle fraction has a mass content of 80 to 95% of the aluminum oxide and the second particle fraction has the aluminum oxide The mass content of 5 to 20%. 4. The epoxy resin casting composition according to any one of the preceding claims, characterized in that the median value of the first particle fraction is 25 μm to 35 μm, especially 30 μm, and that the median value of the second particle fraction is 1 μm to 2 μm, especially 1.5 μm. 5. The epoxy resin casting compound according to any one of the preceding claims, characterized in that, for the first particle fraction, the 10% percentile is 5 μm to 15 μm, especially 10 μm, 25% percentile The quantile is 15 μm to 25 μm, especially 20 μm, the 75th percentile is 35 μm to 45 μm, especially 40 μm, and the 90th percentile is 45 μm to 55 μm, especially 50 μm. 6. The epoxy resin casting compound according to any one of the preceding claims, characterized in that, for the second particle fraction, the 10% percentile is 0.1 μm to 1 μm, especially 0.5 μm, 25% percentile The quantile is 0.5 μm to 1.5 μm, especially 1 μm, the 75th percentile is 1 μm to 4 μm, especially 2.5 μm, and the 90th percentile is 2 μm to 7 μm, especially 4.5 μm. 7. The epoxy resin casting compound according to any one of the preceding claims, characterized in that the aluminum oxide comprises substantially spherical particles. 8. The epoxy resin casting compound as claimed in claim 1, characterized in that the additive is produced from acid esters based on polyether polyols. 9. A method for preparing an epoxy resin castable, said epoxy resin castable being made from a mixture of epoxy resin, aluminum oxide and additives for achieving the specific elasticity of said castable, characterized in that said Mixing of two particle fractions in a casting resin, wherein the first particle fraction has a mass content of more than 80%, preferably 85 to 95%, particularly preferably 89% to 91%, of the filler and has on average larger particles than the second particle fraction . 10. Use of a curable epoxy resin casting composition according to any one of the preceding claims as an electrical insulation material for electrical or electronic components. 11. An electrical machine with electrical windings comprising a curable epoxy resin potting compound according to any one of the preceding claims and being provided for insulating said electrical windings, transporting heat away from said electrical windings and attenuating Acoustic vibrations in the motor.