Method for producing thin carbon fiber nonwovens by a horizontal splitting process

Abstract

A method for horizontally splitting rolled-up web material in the sample thickness. A carbon fiber nonwoven is moved in relation to a knife structure in order to split off a layer or successively several layers from a roll web. The one layer or several layers are continuously removed in the form of a roll from the carbon fiber nonwoven after the splitting process.

Claims

1. A method of insulating a high temperature treatment zone, the method comprising: producing a layer made of carbon fiber non-woven fabric, the step of producing the layer including: providing a starting material being a carbon fiber non-woven fabric; subjecting the starting material to a horizontal splitting process in a sample thickness, by moving the carbon fiber non-woven fabric relative to a blade construction and separating one layer or a plurality of layers consecutively from the carbon fiber non-woven fabric; and continuously removing the one layer or the plurality of layers from the carbon fiber non-woven fabric following the splitting process; and insulating the high temperature treatment zone with the one layer or the plurality of layers forming a high-temperature insulating material.

2. The method according to claim 1, wherein a thickness of the carbon fiber non-woven fabric to be split is 3 mm to 50 mm.

3. The method according to claim 1, wherein a thickness of a separated layer is at least 0.2 mm.

4. The method according to claim 1, wherein said carbon fiber non-woven fabric is based on a material selected from the group consisting of viscose, PAN, pitch and lignin.

5. The method according to claim 1, wherein the blade construction is selected from the group consisting of milling cutter cutting tools, band knives, double band knives having two adjacent single band knives, each of which is sharpened on one side, and rigid, ruler-shaped splitting knives having an oscillating drive.

6. The method according to claim 1, which comprises separating and removing the one or more layers simultaneously and with constant tensile force.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) The FIGURE is a diagrammatic side view illustrating the method according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

(2) Referring now to the sole FIGURE of the drawing in detail there is shown how a carbon fiber non-woven fabric body 1 according to the invention, here a web of material, is split into two halves by a rotating band knife 4 and worked so as to form rolled goods by transport rollers 3. Following the split, the non-woven web 1 is separated into two equal-thickness layers, including a separated layer 2. It will be understood that an asymmetrical splitting process is technically possible in addition to the illustrated symmetrical splitting process. As continuous sharpening is possible, continuous working can occur, which leads to a constantly good cutting image.

Exemplary Embodiment

(3) A 6 mm-thick carbon fiber felt based on viscose is split into two 3 mm-thick halves. The thickness of the split rolls is determined by the vertical positions of the feed rollers that convey the material through the machine. Identical settings for the upper and lower rollers are necessary for a symmetrical splitting result.

(4) As the material must be slightly compressed in order to ensure transport, the split should be set to be somewhat smaller than half the original thickness. In the case of the carbon fiber felt, a compression of 10% is used, as there is no material damage at this value. The upper and lower offsets of the transport rollers are therefore 2.7 mm.

(5) The feeding speed of the system is 8 m/min; the rotation speed of the band knife is 5 m/s. The band knife is continuously sharpened in order to ensure a clean cutting image.

(6) The result is two rolls of split felt. The split surface is surprisingly good (optically smooth and uniform). A specific electrical resistance can be measured in the direction of thickness.

(7) A sucking device over the entire felt width ensures that the split product is as free of dust and particles as possible.

(8) The following measured property values (testing carbon materials) of the split carbon fiber felts were based on PAN or viscose:

(9) Determining the ash content (solid matter)

(10) Ash content following DIN 51903 (at 580° C.):

(11) <0.05% (PAN-based);

(12) <0.1% (viscose-based)

(13) Determining the specific electrical resistance according to the current potential method (solid matter)

(14) ER (x/y) following DIN 51911 (perpendicular to the felt plane):

(15) <5 Ωmm (PAN-based);

(16) <12 Ωmm (viscose-based)

(17) Determining the specific electrical resistance according to the current potential method (solid matter)

(18) ER (z) following DIN 51911 (in felt plane):

(19) <2 Ωmm (PAN-based);

(20) <4 Ωmm (viscose-based)

(21) Thermal conductivity at room temperature according to the comparison method (solid matter)

(22) TC according to DIN 51908 (perpendicular to the felt plane):

(23) 0.1-0.4 W/mK (PAN-based);

(24) 0.02-0.1 W/mK (viscose-based).