Conductive polymer material, use of same, and a method for the production of same

Abstract

The invention relates to a conductive elastomer provided and formed from a base elastomer and conductive solid particles that are distributed therein. The conductive particles used are: a) platelet-shaped conductive particles and/or b) dendritic conductive particles and/or c) other elongated conductive particles with a length:width ratio of greater than or equal to two. It has been seen that a combination of ball-shaped and platelet-shaped conductive particles is particularly advantageous. The particles can additionally be aligned by the pouring, application using a doctor blade, or drawing of the dissolved or not-yet cured mixture. The polymer is particularly suitable for medical electrodes for capturing and emitting signals. The material rennulus elastic, and conductive when stretched or bent.

Claims

1. A skin overlay for electrodes, sensors, measuring feelers, flexible conductor paths to be arranged on skin of a user, medical devices being in direct contact with skin of a user, elastic bandages, liners, sleeves, ortheses and parts thereof, and prostheses and parts thereof, comprising: a conductive polymer material made of a base polymer which is an elastomer; and conductive solid particles other than carbon black particles distributed in the base polymer, wherein said conductive solid particles are of a micrometer scale and are embedded in the base polymer and distributed substantially homogenously throughout a volume of the base polymer and are not in the form of layers or clusters, wherein said conductive solid particles include one or more of plate-shaped conductive particles having conductively coated plate main bodies formed from an inorganic-oxidic carrier material and which have a width and length of 1 m to 60 m and a height of 100 nm to 1 m, wherein said conductive polymer material is configured as a skin overlay having reversible longitudinal resiliency wherein conductivity of the conductive polymer material is maintained up to an elongation of at least 25%.

2. The skin overlay of claim 1 wherein the base polymer is selected from the group consisting of silicone, polyurethane, and rubber.

3. The skin overlay of claim 1 further comprising spherical conductive particles in the base polymer.

4. The skin overlay of claim 3, wherein a weight ratio of the spherical conductive particles to the plate-shaped conductive particles ranges from 10:90 to 90:10.

5. The skin overlay of claim 4 wherein the ratio ranges from 10:90 to 60:40.

6. The skin overlay of claim 3 wherein the spherical conductive particles have a diameter ranging from 500 nm to 25 m.

7. The skin overlay of claim 1 wherein the conductive solid particles are partially aligned or partially concatenated to form chains.

8. The skin overlay of claim 1 further comprising an intrinsically conductive polymer is contained in said conductive polymer material at a fraction of up to 30 wt. %.

9. The skin overlay of claim 1 wherein said conductive polymer material is configured as a pad or cushion.

10. The skin overlay of claim 1 wherein said conductive polymer material is configured as an electrode for signal acquisition, signal generation, or stimulation.

11. The skin overlay of claim 1 wherein said conductive polymer material is configured as a moisture sensor or stimulus transmission sensor.

12. The skin overlay of claim 1 wherein said elastomer is a thermoplastic elastomer.

13. The skin overlay of claim 1 wherein the base polymer is selected from the group consisting of elastic polyurethane, thermoplastic polyurethane (TPU), polyurethane gel, silicone gel, latex, and synthetic rubber.

14. The skin overlay of claim 1 wherein a volume resistivity of the conductive polymer material is not more than 1000 k.Math.cm measured using a two wire circuit conductivity test.

15. A method for producing a skin overlay for electrodes, sensors, measuring feelers, flexible conductor paths to be arranged on skin of a user, medical devices being in direct contact with skin of a user, elastic bandages, liners, sleeves, ortheses and parts thereof, and prostheses and parts thereof, comprising: admixing a base polymer which is an elastomer or precursor of said elastomer with conductive solid particles other than carbon black particles, wherein said conductive solid particles are of a micrometer scale and include one or more of plate-shaped conductive particles having conductively coated plate main bodies formed from an inorganic-oxidic carrier material and which have a width and length of 1 m to 60 m and a height of 100 nm to 1 m; aligning the conductive solid particles when said base polymer is either in a dissolved state or in a molten state, or when said precursors are in a process of reaction but are not yet fully reacted; and fixing said conductive solid particles in alignment in said base polymer after said aligning step to form a conductive polymer material for use as a skin overlay by solidifying said base polymer, wherein the conductive polymer material has reversible longitudinal resiliency wherein conductivity of the conductive polymer material is maintained up to an elongation of at least 25%.

16. The method as claimed in claim 15, wherein said base polymer is permitted to flow during said aligning step.

17. The method of claim 16 wherein said flow during said aligning step is achieved by one or more of scraping, extrusion or other pressing through a die, and drawing of films.

18. The method of claim 15 wherein said admixing step is performed such that wherein said conductive solid particles are embedded in the base polymer and distributed substantially homogenously throughout a volume of the base polymer and are not in the form of layers or clusters.

19. A method for producing a skin overlay for electrodes, sensors, measuring feelers, flexible conductor paths to be arranged on skin of a user, medical devices being in direct contact with skin of a user, elastic bandages, liners, sleeves, ortheses and parts thereof, and prostheses and parts thereof, comprising: admixing a base polymer which is an elastomer or precursor of said elastomer with conductive solid particles other than carbon black particles, wherein said conductive solid particles include one or more of plate-shaped conductive particles having conductively coated plate main bodies formed from an inorganic-oxidic carrier material; aligning the conductive solid particles when said base polymer is either in a dissolved state or in a molten state, or when said precursors are in a process of reaction but are not yet fully reacted; and fixing said conductive solid particles in alignment in said base polymer after said aligning step to form a conductive polymer material for use as a skin overlay by solidifying said base polymer, wherein the conductive polymer material has a reversible longitudinal resiliency wherein conductivity of the conductive polymer material is maintained up to an elongation of at least 25% wherein said base polymer is permitted to flow during said aligning step.

20. The method of claim 19 wherein said admixing step is performed such that wherein said conductive solid particles are embedded in the base polymer and distributed substantially homogenously throughout a volume of the base polymer and are not in the form of layers or clusters.

Description

FIGURES

(1) FIG. 1 SEM photograph of a polymer having spherical metal particles in 250-fold enlargement;

(2) FIG. 2 like FIG. 1, in 3000-fold enlargement;

(3) FIG. 3 SEM photograph of a conductivity additive, mixed from plate-shaped and spherical particles, 1000-fold enlargement;

(4) FIG. 4 SEM photograph of a conductivity additive in TPU, aligned;

(5) FIG. 5 like FIG. 4, but unaligned/unordered;

CONDUCTIVITY TESTS

(6) 1. Two-wire Circuit:

(7) The specific contact resistance of the sample bodies is determined from the contact resistance and the thickness of the sample body. A two-wire circuit is used for this purpose. Planar front and rear side contacting of a thin film-type sample body having a round surface (r=16 mm) is performed by means of round measuring electrodes. The measurement of the resistance is carried out by means of DMM VC 940 (VOLTCRAFT, DE). The lower contact electrode is formed by a gold-plated contact pad, the upper counter electrode by a round titanium electrode. 2. Four-point Measurement

(8) The four-point method is a standard measuring method from semiconductor technology. The sample body is contacted with four equidistant points arranged in a colinear manner in a Wenner arrangement. A defined constant current is applied via the outer points and the potential drop is measured via the inner points.

(9) Tests of Mechanical PropertiesTensile Tests

(10) With the aid of the tensile test, the influence of the additive content on the mechanical properties of the base polymer is studied and evaluated. The tensile test is carried out on a testing machine Zwick Z010 (producer Roell) using an S2 sample body. The tensile test is a standard method according to DIN EN ISO 527 to ascertain the material behavior in the case of single-axis, uniform tensile stress distributed over the cross-section. The characteristic values may be ascertained from the stress-strain graph (SSG). For rubber-elastic materials, a type III strain graph is expected. The yield stress is the first maximum in the SSG, the tensile strength is the tensile stress at maximum force, and the tear resistance is the tensile stress at the moment of tearing. To compare the polymer samples, the yield stress is selected. All tensile tests are carried out without prior load of the sample bodies, the ascertained mechanical values are initial strain values.

(11) Tables

(12) The abbreviations indicated in the following tables have the following meanings: m.sub.A: mass of additive [kg]; m.sub.P: mass of polymer [kg]; m.sub.PG: mass of polymer mixture [kg]; m.sub.PA: mass of polymer component A [kg]; m.sub.PB: mass of polymer component B [kg]; c.sub.mA: mass concentration of the additive [%]; c.sub.mP: mass concentration of polymer [%]; c.sub.VA: volume concentration of the additive Vol; c.sub.VP: volume concentration of the polymer [%]; .sub.D: specific electrical contact resistance [m]; .sub.S: specific electrical layer resistance [m]; .sub.D: specific electrical contact conductivity [S/m]; .sub.S: specific electrical layer conductivity [S/m]; : mechanical stress [N/m.sup.2]

(13) As FIGS. 1 and 2 show in conjunction with Table 7, a conductive elastomer in the sense of this invention cannot be obtained using spherical conductivity additives, since the particles are still individually enclosed by polymer and thus insulated, even at high concentration.

(14) The situation is different in the case of plate-shaped or oblong particles, as shown in FIG. 3 (in the mixture with spherical particles). Using these particles, the percolation threshold is exceeded significantly earlier, so that less conductivity additive is necessary to achieve a specific desired conductivity. The mechanical properties of the base polymer are disturbed less by the lower content of conductive particles.

(15) Plate-shaped or elongated particles also maintain contact better under mechanical load of a body made of the conductive polymerfor example, in the event of bending movements, elongations, or tortionsso that conductivity is retained.

(16) The retention of the properties is confirmed by the data in the tables.

(17) The scale on the right lower edge of FIGS. 1 to 3 is as follows:

(18) in FIG. 1: 300 m, in FIG. 2: 30 m, in FIG. 3: 100 m.

(19) Alignment of Plate-Shaped Particles

(20) FIGS. 1 and 5 show the effect of the alignment of plate-shaped particles. FIG. 4 shows the scanning electron microscope photograph of a cross-sectional view through a sample piece made of TPU with plate-shaped conductive particles, which were aligned during the production of the layer by scraping. A state of increased order results in relation to the nonaligned or unordered, but otherwise completely corresponding material, as shown in FIG. 5 (the scale at the right lower edge of the figure is 100 m in each case in FIGS. 4 and 5). As can be seen from FIG. 4, the plates partially become ordered and concatenate to form chain-like formations. The percolation is increased. Ordered and unordered or aligned and nonaligned states can be visually differentiated.

(21) TPU with Ag Particles of Dendritic Form

(22) a.fwdarw.silver powder GN1 b.fwdarw.silver powder AGPE0160-6

(23) TABLE-US-00001 TABLE 1 formula specifications - TPU with dendritic Ag particles additive content AMI DODUCO TPU net silver powder TPU-THF (18.35%) Vol-% sample mass-% mixture mass-% THF Ag TPU number c.sub.mA m.sub.A m.sub.PG m.sub.P c.sub.mP additive c.sub.VA c.sub.VP 6 a 89.7% 10.500 g 6.54 g 1200 g 10.3% 50% 50% 6 b 7 a 85.4% 5.535 g 5.171 g 0.949 g 14.6% 40% 60% 7 b 5.520 g 5.157 g 0.946 g 8 a 78.9% 4.906 g 7.130 g 1.308 g 21.1% 30% 70% 8 b 5.290 g 7.688 g 1.411 g 9 a 68.6% 4.761 g 11.861 g 2.176 g 31.4% 20% 80% 9 b 4.827 g 12.025 g 2.207 g 10 a 65.8% 3.359 g 9.530 g 1.749 g 34.2% 18% 82% 10 b 3.035 g 8.611 g 1.580 g 11 a 62.5% 2.241 g 7.328 g 1.345 g 37.5% 16% 84% 11 b 2.580 g 8.436 g 1.548 g

(24) TABLE-US-00002 TABLE 2 results table - TPU with dendritic Ag particles electrical properties layer sample number .sub.S/[ .Math. cm] .sub.S/[S/cm] 6 a 1.215 0.823 6 b 0.845 1.183 7 a 1.276 0.784 7 b 1.215 0.823 8 a 5.13 0.195 8 b 4.30 0.233 9 a 16.09 0.062 9 b 14.02 0.071 10 a 48.91 0.020 10 b 40.55 0.025 11 a 144.20 0.007 11 b 73.58 0.014
Silicone Rhodia SILBIONE RTV4411 with Minatec 60 CM

(25) TABLE-US-00003 TABLE 3 formula specifications - silicone with Minatec additive content Minatec Silicone Rhodia 60 CM RTV 4411 component Vol-% sample mass-% mass-% +35% HMDS Minatec Silicone number c.sub.mA m.sub.A m.sub.PA m.sub.P3 c.sub.mP (m.sub.PA + m.sub.A .fwdarw. 100%) c.sub.VA c.sub.VP 12 38% 3.370 g 5.000 g 0.500 g 62% 2.930 g 16.8% 83.2% 13 39% 3.510 g 61% 2.980 g 17.4% 82.6% 14 40% 3.670 g 60% 3.030 g 18.0% 82.0% 15 41% 3.820 g 59% 3.090 g 18.6% 81.4% 16 42% 3.980 g 58% 3.140 g 19.2% 80.8% 17 43% 4.150 g 57% 3.200 g 19.9% 80.1% 18 44% 4.320 g 56% 3.260 g 20.6% 79.4% 19 45% 4.500 g 55% 3.330 g 21.2% 78.8%

(26) TABLE-US-00004 TABLE 4 results table - specific electrical conductivity (silicone/Minatec) Number Percentage Mechanical properties of electrical properties measurement Yield Elongation sample sample contact deviation stress at yield number bodies .sub.D/[ .Math. cm] .sub.D/[S/cm] .sub.D,g/.sub.D [N/mm.sup.z] [%] 12 9 18.1 .Math. 10.sup.6 (0.055 0.041) .Math. 10.sup.6 74.6% 0.87 61 13 8.68 .Math. 10.sup.6 (0.115 0.070) .Math. 10.sup.6 60.8% 0.89 62 14 3.27 .Math. 10.sup.6 (0.306 0.087) .Math. 10.sup.6 28.5% 0.94 56 15 1.55 .Math. 10.sup.6 (0.65 0.27) .Math. 10.sup.6 42.4% 0.81 44 16 0.629 .Math. 10.sup.6 (1.59 0.45) .Math. 10.sup.6 28.2% 1.00 40 17 0.388 .Math. 10.sup.6 (2.6 1.1) .Math. 10.sup.6 41.3% 0.96 34 18 0.276 .Math. 10.sup.6 (3.6 1.5) .Math. 10.sup.6 40.6% 0.73 28 19 0.174 .Math. 10.sup.6 (5.8 1.8) .Math. 10.sup.6 30.7% 0.35 15
TPU SEETHAN 2403 K with Minatec 60 CM

(27) TABLE-US-00005 TABLE 5 formula specifications - TPU with Minatec additive content TPU net Minatec TPU-THF (18.35%) Vol-% sample 60 CM mass-% mixture mass-% THF Minatec TPU number c.sub.mA m.sub.A m.sub.PG m.sub.P c.sub.mP additive c.sub.VA c.sub.VP 20 17% 3.312 g 88.122 g 16.170 g 83% 6.7% 93.3% 21 18% 1.074 g 26.633 g 4.887 g 82% 7.2% 92.8% 22 19% 3.083 g 71.626 g 13.143 g 81% 7.6% 92.4% 23 20% 4.022 g 87.673 g 16.088 g 80% 8.1% 91.9% 24 22% 4.122 g 79.642 g 14.614 g 78% 9.1% 90.9% 25 24% 5.447 g 93.999 g 17.249 g 76% 10.0% 90.0% 26 26% 3.033 g 47.043 g 8.632 g 74% 11.0% 89.0% 27 31% 4.339 g 52.631 g 9.658 g 69% 13.7% 86.3% 28 38% 3.162 g 28.115 g 5.159 g 62% 17.8% 82.2% 29 39% 5.378 g 45.841 g 8.412 g 61% 18.4% 81.6% 30 40% 3.609 g 29.501 g 5.413 g 60% 19.0% 81.0% 31 41% 4.058 g 31.823 g 5.840 g 59% 19.7% 80.3% 32 42% 4.101 g 30.863 g 5.663 g 58% 20.4% 79.6% 33 43% 4.054 g 29.286 g 5.374 g 57% 21.0% 79.0% 34 44% 5.466 g 37.911 g 6.957 g 56% 21.7% 78.3% 35 45% 5.243 g 34.922 g 6.408 g 55% 22.4% 77.6% 36 46% 4.936 g 31.577 g 5.794 g 54% 23.1% 76.9% 37 47% 5.220 g 32.078 g 5.886 g 53% 23.8% 76.2% 38 48% 4.284 g 25.292 g 4.641 g 52% 24.6% 75.4% 39 49% 5.259 g 29.829 g 5.474 g 51% 4.0 g 25.3% 74.7% 40 50% 8.663 g 47.210 g 8.663 g 50% 3.7 g 26.1% 73.9% 41 51% 8.135 g 42.594 g 7.816 g 49% 3.7 g 26.9% 73.1% 42 52% 6.866 g 34.539 g 6.338 g 48% 4.3 g 27.7% 72.3%

(28) TABLE-US-00006 TABLE 6 results table - specific electrical conductivity (TPU/Minatec) Number Precentage Mechanical properties of electrical properties measurement Yield Elongation sample sample contact deviation stress at yield number bodies .sub.D/[ .Math. cm] .sub.D/[S/cm] .sub.D,q/.sub.D [N/mm.sup.2] [%] 20 5 37.53 623 21 36.15 636 22 85.0 .Math. 10.sup.6 0%: (0.012 0.022) .Math. 10.sup.6 186.1% 31.43 556 37.5 .Math. 10.sup.6 57%: (0.027 0.061) .Math. 10.sup.6 229.4% 56.8 .Math. 10.sup.6 99%: (0.017 0.033) .Math. 10.sup.6 186.6% 23 21.3 .Math. 10.sup.6 0%: (0.047 0.057) .Math. 10.sup.6 120.8% 32.02 574 22.4 .Math. 10.sup.6 57%: (0.045 0.048) .Math. 10.sup.6 108.4% 23.0 .Math. 10.sup.6 99%: (0.044 0.027) .Math. 10.sup.6 63.0% 24 2.76 .Math. 10.sup.6 0%: (0.36 0.32) .Math. 10.sup.6 89.2% 30.04 529 3.47 .Math. 10.sup.6 57%: (0.29 0.19) .Math. 10.sup.6 66.8% 3.97 .Math. 10.sup.6 99%: (0.25 0.18) .Math. 10.sup.6 72.2% 25 431 .Math. 10.sup.3 0%: (2.3 1.0) .Math. 10.sup.6 44.1% 31.47 607 632 .Math. 10.sup.3 57%: (1.58 0.61) .Math. 10.sup.6 38.6% 640 .Math. 10.sup.3 99%: (1.56 0.93) .Math. 10.sup.6 59.4% 26 171 .Math. 10.sup.3 0%: (5.83 0.85) .Math. 10.sup.6 14.7% 8.01 57.9 239 .Math. 10.sup.3 57%: (4.2 1.4) .Math. 10.sup.6 32.2% 243 .Math. 10.sup.3 99%: (4.1 2.1) .Math. 10.sup.6 49.7% 27 70.5 .Math. 10.sup.3 0%: (14.2 4.8) .Math. 10.sup.6 34.1% 7.96 27.0 75.6 .Math. 10.sup.3 57%: (13.2 6.1) .Math. 10.sup.6 46.4% 86.4 .Math. 10.sup.3 99%: (11.6 8.0) .Math. 10.sup.6 68.8% 28 29.7 .Math. 10.sup.3 0%: (34 32) .Math. 10.sup.6 94.3% 8.10 18.9 43.0 .Math. 10.sup.3 57%: (23 14) .Math. 10.sup.6 58.6% 28.9 .Math. 10.sup.3 99%: (35 15) .Math. 10.sup.6 42.4% 29 55.3 .Math. 10.sup.3 0%: (18 16) .Math. 10.sup.6 89.2% 7.66 17.0 88.0 .Math. 10.sup.3 57%: (11.4 18.3) .Math. 10.sup.6 72.7% 63.5 .Math. 10.sup.3 99%: (15.8 7.7) .Math. 10.sup.6 48.6% 30 31.0 .Math. 10.sup.3 0%: (32 31) .Math. 10.sup.6 95.4% 8.61 16.2 51.0 .Math. 10.sup.3 57%: (20 16) .Math. 10.sup.6 82.4% 28.2 .Math. 10.sup.3 99%: (36 26) .Math. 10.sup.6 73.1% 31 49.3 .Math. 10.sup.3 0%: (20 13) .Math. 10.sup.6 65.3% 8.25 15.6 77.1 .Math. 10.sup.3 57%: (13.0 6.5) .Math. 10.sup.6 50.3% 54.7 .Math. 10.sup.3 99%: (18 23) .Math. 10.sup.6 126.9% 32 23.2 .Math. 10.sup.3 0%: (43 32) 10.sup.6 74.2% 9.25 14.3 37.7 .Math. 10.sup.3 57%: (27 18) .Math. 10.sup.6 67.5% 20.8 .Math. 10.sup.3 99%: (48 17) .Math. 10.sup.6 35.4% 33 34.0 .Math. 10.sup.3 0%: (29 13) .Math. 10.sup.6 45.5% 9.13 13.1 35.9 .Math. 10.sup.3 57%: (28 21) .Math. 10.sup.6 73.7% 36.9 .Math. 10.sup.3 99%: (27 15) .Math. 10.sup.6 56.8% 34 37.7 .Math. 10.sup.3 0%: (26.5 5.9) .Math. 10.sup.6 22.4% 8.86 12.0 40.6 .Math. 10.sup.3 57%: (25 18) .Math. 10.sup.6 71.7% 51.8 .Math. 10.sup.3 99%: (19 13) .Math. 10.sup.6 65.7% 35 29.5 .Math. 10.sup.3 0%: (34 22) .Math. 10.sup.6 64.4% 9.97 12.0 41.9 .Math. 10.sup.3 57%: (24 12) .Math. 10.sup.6 48.4% 27.6 .Math. 10.sup.3 99%: (36 16) .Math. 10.sup.6 43.4% 36 35.2 .Math. 10.sup.3 0%: (28 26) .Math. 10.sup.6 92.2% 9.50 10.8 71.5 .Math. 10.sup.3 57%: (14.0 9.9) .Math. 10.sup.6 70.6% 60.2 .Math. 10.sup.3 99%: (17 17) .Math. 10.sup.6 103.6% 37 24.9 .Math. 10.sup.3 0%: (40 30) .Math. 10.sup.6 75.6% 9.86 10.8 31.0 .Math. 10.sup.3 57%: (32.2 4.3) .Math. 10.sup.6 13.4% 33.1 .Math. 10.sup.3 99%: (30 19) .Math. 10.sup.6 62.9% 38 16.4 .Math. 10.sup.3 0%: (61 25) .Math. 10.sup.6 40.3% 9.54 9.7 23.9 .Math. 10.sup.3 57%: (42 25) .Math. 10.sup.6 60.2% 25.0 .Math. 10.sup.3 99%: (40 15) .Math. 10.sup.6 38.0% 39 12.9 .Math. 10.sup.3 0%: (78 44) .Math. 10.sup.6 57.4% 9.94 9.6 22.1 .Math. 10.sup.3 57%: (45 22) .Math. 10.sup.6 47.7% 25.0 .Math. 10.sup.3 99%: (40 25) .Math. 10.sup.6 62.8% 40 30.0 .Math. 10.sup.3 0%: (33 11) .Math. 10.sup.6 34.1% 12.32 8.29 36.4 .Math. 10.sup.3 57%: (28 19) .Math. 10.sup.6 70.2% 26.8 .Math. 10.sup.3 99%: (37 30) .Math. 10.sup.6 80.1% 41 17.1 .Math. 10.sup.3 0%: (58 33) .Math. 10.sup.6 55.8% 9.56 7.6 29.4 .Math. 10.sup.3 57%: (34 22) .Math. 10.sup.6 63.5% 30.2 .Math. 10.sup.3 99%: (33 23) .Math. 10.sup.6 70.0% 42 21.5 .Math. 10.sup.3 0%: (47 21) .Math. 10.sup.6 45.4% 8.89 8.5 34.3 .Math. 10.sup.3 57%: (29 11) .Math. 10.sup.6 36.7% 11.8 .Math. 10.sup.3 99%: (85 146) .Math. 10.sup.6 171.8%
Reference: Spherical SilverCopper Particles in Silicone

(29) TABLE-US-00007 TABLE 7 formula specifications - silicone with spherical metallic additives additive Silicone Rhodia content RTV 4411 FOXMET component Vol-% sample mass-% mass-% HMDS Foxmet Silicone number c.sub.mA m.sub.A m.sub.PA m.sub.PS c.sub.mP m.sub.L c.sub.VA c.sub.VP 3 50% 5.50 g 5.000 g 0.500 g 50% 10.1% 89.9% 4 70% 12.83 g 30% 20.7% 79.3% 5 92% 63.25 g 8% 56.3% 43.7% No electrical conductivity!
Reference: Wacker Elastosil

(30) TABLE-US-00008 TABLE 8 formula specifications - Wacker Elastosil production method sample Manual Concentration Furnace number type solvent batch calender Additive m.sub.1 m.sub.2 Temperature Time 1 LR 3162 HMDS 10 Carbon 25 g 25 g 170 C. 10 minutes minutes black 2 R 573 70A X Carbon 50 g 50 g 150 C. 12 hours black

(31) TABLE-US-00009 TABLE 9 results table - Wacker Elastosil Number Percentage of electrical properties measurement sample sample contact deviation number bodies .sub.D/[ .Math. cm] .sub.D/[S/cm] .sub.D/.sub.D 1 3 8.06 .Math. 10.sup.3 (0.12 0.02) .Math. 10.sup.3 16.7% 2 1.61 .Math. 10.sup.3 (0.62 0.04) .Math. 10.sup.3 6.5%