Ground expanded graphite agglomerates, methods of making, and applications of the same

A technology of expanded graphite, agglomerates, applied in the direction of graphite, chemical instruments and methods, materials for heat exchange, etc., can solve problems such as workability problems that are not described

Active Publication Date: 2013-06-05
IMERYS GRAPHITE & CARBON SWITZERLAND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Grigorian et al. do not describe any processability issues observed for expanded

Method used

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  • Ground expanded graphite agglomerates, methods of making, and applications of the same
  • Ground expanded graphite agglomerates, methods of making, and applications of the same
  • Ground expanded graphite agglomerates, methods of making, and applications of the same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0136] Example 1 - Coalescence method for expanded graphite

[0137]To prepare comminuted expanded graphite agglomerates, initially comminuted expanded graphite is fed onto a pair of counter-rotating rollers with the aid of a screw. The expanded graphite was pre-coalesced by passing it through rollers. In this example, a drum with a smooth surface was used (although the drum could also have a structured surface to increase productivity). In the second step (fine agglomeration step), the pre-agglomerated expanded graphite is pushed through a final sieve or set of sieves with the help of rotating jaws, which help define the agglomerate size of the comminuted expanded graphite (see Figure 15 ). The desired tap density is adjusted by proper selection of the screw speed, the gap between the rollers, and the mesh size to produce the desired soft agglomerates of comminuted expanded graphite (manufactured by Alexanderwerk AG, Remscheid, Germany). roller compactor PP150).

[0138]...

Embodiment 2

[0141] Example 2 - Alternative coalescence method for expanded graphite

[0142] In an alternative setup, agglomerates of comminuted expanded graphite are produced using machines with different geometric arrangements. In this setup, as in Figure 16 As shown in , the material is fed vertically onto counter-rotating drums with the help of a vertical screw (Powtec RC210 manufactured by Powtec Maschinen und Engineering, Remscheid, Germany). The tap density is again adjusted via screw speed, drum gap and final mesh size.

Embodiment 3

[0143] Example 3 - Alternative coalescence method for expanded graphite

[0144] Pin mixer granulation method

[0145] In an alternative method, the agglomerates can be produced using a pin mixer granulator system generally known in the art. For example, such pin mixer granulator systems are widely used to agglomerate carbon black powders. Pin mixers consist of a cylindrical stable housing and a rotating shaft equipped with pins. Initially comminuted expanded graphite enters the system at one end of the cylinder and, as it moves from the inlet, can be whipped by a rotating pin, through the housing and to the bottom outlet. A fine particle spray of liquid or vapor can be added at the inlet section and distributed throughout the powder, which results in fine mixing and micro-agglomeration of the particles. In this embodiment, the liquid or vapor may be water, although generally any inert liquid will work in this setup. Also, additives can be added at this stage.

[0146] ...

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PUM

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Abstract

The present disclosure relates to ground expanded graphite agglomerate compositions, methods for making such agglomerates, their use as conductive additive, and conductive composites comprising such ground expanded graphite agglomerates. The disclosure also pertains to methods for making such composites and the use of such composites in preparing thermally conductive materials. The agglomerates are characterized by a certain softness allowing the agglomerates to dissolve, e.g., through shear forces applied during compounding, thereby leading to an improved feedability and a highly homogenous distribution of the expanded graphite material in the composite matrix.

Description

[0001] related application [0002] This application claims the benefit of US Provisional Application 61 / 372,479 and EP Application No. 10172468.0, filed August 11, 2010, the entire contents of which are hereby incorporated by reference. technical field [0003] The present disclosure relates to comminuted expanded graphite agglomerate compositions useful as conductive additives, methods of their preparation, and their use in composite materials such as polymer blends, ceramics, and inorganic materials. Background technique [0004] Graphite powder is a promising filler (i.e., conductive additive) for thermally and electrically conductive polymers and other composite materials. [0005] Expanded or exfoliated graphite (also known as nanographite or nanostructured graphite) has recently attracted increasing attention due to its excellent thermal and electrical properties. Expanded graphite is superior to non-expanded graphite and other conductive fillers (eg boron nitride, c...

Claims

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Application Information

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IPC IPC(8): C01B31/04H01B1/24
CPCH01B1/04B02C19/0056C08K3/04H01B1/24C01B31/0423C01B31/04C01B32/225C08K2201/005Y10T428/2982C01P2004/50C01P2006/11C01P2006/12C01P2006/32C09K5/14C01B32/21
Inventor 尤塞比乌·格里维法比奥·罗塔让-克里斯托夫·里特切西蒙尼·齐歇尔拉法埃莱·希拉尔迪米夏埃尔·斯帕尔
Owner IMERYS GRAPHITE & CARBON SWITZERLAND
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