# US 5,344,635 A · Filler for heat-conductive plastics materials

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- Number: US 5,344,635 A
- Document ID: US5344635A
- Status: Granted
- Kind: A
- Application number: 08/011,930
- Filed: 1993-02-01
- Granted: 1994-09-06
- Earliest claimed: 1992-02-07
- Assignees: Ciba-Geigy Corporation
- Inventors: Patrice Bujard; Ileana Cojanu
- Web page: https://patentgrep.com/patent/US5344635A

## CPC

- C01B 21/072: with aluminium
- C08K 3/28: Nitrogen-containing compounds
- C01P 2004/50: Agglomerated particles
- C01P 2004/51: Particles with a specific particle size distribution
- C01P 2004/61: Micrometer sized, i.e. from 1-100 micrometer
- C01P 2004/62: Submicrometer sized, i.e. from 0.1-1 micrometer
- C01P 2006/32: Thermal properties
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)
- C01P: INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS

## Abstract

A powder mixture of aluminium nitride in the form of sintered agglomerates with fractions of different particle size, which mixture comprises (1) 80 to 50% by weight of aluminium nitride in the form of sintered agglomerates having a mean particle diameter of 30 to 50 .mu.m, and (2) 20 to 50% by weight of aluminium nitride in the form of unsintered particles and having a mean particle diameter of 0.1 to 5 .mu.m. The mixture is suitable for use as filler for polymer materials, especially for casting resins, from which moulded parts of high thermal conductivity can be fabricated, for example potted electronic components.

## Claims

### Claim 1

A powder mixture of aluminium nitride in the form of sintered agglomerates with fractions of different particle size, which mixture consists essentially of
(1) 80 to 50% by weight of aluminium nitride in the form of sintered agglomerates having a mean particle diameter of 30 to 50 .mu.m, and
(2) 20 to 50% by weight of aluminium nitride in the form of unsintered particles and having a mean particle diameter of 0.1 to 5 .mu.m.

### Claim 2 (depends on 1)

A mixture according to claim 1, which consists essentially of
a) 77.5 to 55% by weight of component (1), and
b) 22.5 to 45% by weight of component (2).

### Claim 3 (depends on 1)

A mixture according to claim 1, which consists essentially of
a) 75 to 60% by weight of component (1), and
b) 25 to 40% by weight of component (2).

### Claim 4 (depends on 1)

A mixture according to claim 1, which consists essentially of
a) 75 to 65% by weight of component (1), and
b) 25 to 35% by weight of component (2).

### Claim 5 (depends on 1)

A mixture according to claim 1, wherein the mean particle size of component (1) is 35 to 45 .mu.m, and the mean particle size of component (2) is 1 to 2 .mu.m.

### Claim 6 (depends on 1)

A mixture according to claim 1, wherein component (1) consists essentially of
a) 4 to 40% by weight of A1N particles having a diameter of 50 to 100 .mu.m,
b) 35 to 70% by weight of A1N particles having a diameter of 20 to smaller than 50 .mu.m, and
c) 4 to 25% by weight of A1N particles having a diameter smaller than 20 .mu.m, the percentages adding up to 100% by weight.

### Claim 7 (depends on 6)

A mixture according to claim 6, wherein component (1) consists essentially of
a) 10 to 35% by weight of A1N particles having a diameter of 50 to 100 .mu.m,
b) 45 to 70% by weight of A1N particles having a diameter of 20 to smaller than 50 .mu.m, and
c) 5 to 20% by weight of A1N particles having a diameter smaller than 20 .mu.m, the percentages adding up to 100% by weight.

### Claim 8 (depends on 1)

A mixture according to claim 1, wherein component (1) consists essentially of
a) 20 to 35% by weight of A1N particles having a diameter of 50 to 100 .mu.m,
b) 55 to 70% by weight of A1N particles having a diameter of 20 to smaller than 50 .mu.m, and
c) 5 to 15% by weight of A1N particles having a diameter smaller than 20 .mu.m, the percentages adding up to 100% by weight.

### Claim 9 (depends on 1)

A mixture according to claim 1, wherein component (2) consists of particles having a diameter of 3 .mu.m or smaller than 3 .mu.m.