ELECTRICALLY INSULATING THERMALLY CONDUCTIVE POLYMER RESIN COMPOSITION BASED ON STYRENICS WITH BALANCED PROPERTIES

Abstract

Thermally conductive polymer (TCP) resin composition (i) or (ii) are described, comprising components (I) and (II): (i) 40 to 72% by volume of at least one matrix polymer (I); 28 to 60% by volume of a thermally conductive filler material (II) (D.sub.50 0.1 to 200 m) consisting of aluminosilicate (II-1) in combination with a further component (II-2) selected from: multi wall carbon nanotubes, graphite and and boron nitride, wherein the volume ratio (ll-1)/(ll-2) is 30:1 to 0.1:1; or (ii) 40 to 65% by volume of at least one matrix polymer (I); 35 to 60% by volume of aluminosilicate (II) (D.sub.50 0.1 to 200 m); wherein the matrix polymer (I) comprises styrenic polymers (I) selected from: ABS resins, ASA resins, and elastomeric block copolymers. Shaped articles made thereof can be used as Cool Touch surfaces for automobile interior, motor housings, lamp housings and electrical and electronic housings and as heat sinks for high performance electronics or LED sockets.

Claims

1-13. (canceled)

14. A thermally conductive polymer (TCP) resin composition (i) or (ii) comprising components (I) and (II): (i) 40 to 72% by volume of at least one matrix polymer (I) as component (I); 28 to 60% by volume of a thermally conductive filler material (II) as component (II) having a weight median particle diameter (D.sub.50) of from 0.1 to 200 m, which consists of at least one aluminosilicate as component (II-1) in combination with at least one further component (II-2) selected from the group consisting of: multi wall carbon nanotubes, graphite and boron nitride, wherein the volume ratio between components (II-1) and (II-2) is from 30:1 to 0.1:1; or (ii) 40 to 65% by volume of at least one matrix polymer (I) as component (I); 35 to 60% by volume of a thermally conductive filler material (II) as component (II) having a weight median particle diameter (D.sub.50) of from 0.1 to 200 m which consists of at least one aluminosilicate; wherein the matrix polymer (I) comprises styrenic polymers (I) selected from the group consisting of: ABS (acrylonitrile-butadiene-styrene) resins, ASA (acrylonitrile-styrene-acrylate) resins, and elastomeric block copolymers of the structure (S-(B/S)).sub.n-S, where S is a vinylaromatic block forming a hard phase, (B/S) is a random copolymer block of vinylaromatic monomer and of a conjugated diene forming a soft phase, and n are natural numbers from 1 to 10, wherein the elastomeric block copolymer has a monomer composition comprising 25 to 60% by weight (based on the elastomeric block copolymer) of diene and 75 to 40% by weight (based on the elastomeric block copolymer) of vinylaromatic compound, the glass transition temperature Tg of block S is above 25 C. and that of block (B/S) is below 25 C., and the proportion of the hard phase in the elastomeric block copolymer is from 5 to 40% by weight and the relative amount of 1,2 linkages of the polydiene, based on the sum of 1,2- and 1,4-cis/trans-linkages, is less than 15%; and wherein the sum of components (I) and (II) totals 100% by volume, and wherein the surface of the aluminosilicate is treated with a coupling agent.

15. The thermally conductive polymer (TCP) resin composition (i) or (ii) according to claim 14, having a thermal conductivity of more than 0.5 W/m.Math.K.

16. The TCP resin composition according to claim 14, wherein the matrix polymer (I) comprises at least one further thermoplastic polymer (I) selected from the group consisting of: polycarbonates and polyamides.

17. The TCP resin composition according to claim 14, wherein the matrix polymer (I) is selected from the group consisting of: ABS resins, ASA resins, elastomeric block copolymers of the structure (A-(B/A)).sub.n-A, blend of ABS resins with polycarbonate, blend of ABS resins with polyamide, blend of ASA resins with polycarbonate, and blend of ASA resins with polyamide.

18. The TCP resin composition (i) according to claim 14 comprising 55 to 72% by volume of component (I) and 28 to 45% by volume of component (II).

19. The TCP resin composition (i) according to claim 14 wherein component (II-2) is multi wall carbon nanotubes or graphite.

20. The TCP resin composition (i) according to claim 19 comprising 55 to 65% by volume of component (I) and 35 to 45% by volume of component (II).

21. The TCP resin composition (i) according to claim 19 wherein the volume ratio between components (II-1) and (II-2) is from 30:1 to 1:1.

22. The TCP resin composition (i) or (ii) according to claim 14 wherein the matrix polymer (I) consists of an elastomeric linear styrene-butadiene block copolymer of the general structure S-(B/S)-S having, situated between the two styrene S blocks, one (B/S)-random block having random styrene/butadiene distribution.

23. The TCP resin composition (i) according to claim 14 wherein component (II-2) is boron nitride and the volume ratio between components (II-1) and (II-2) is from 10:1 to 0.1 to 1.

24. A process for the preparation of the TCP resin composition (i) or (ii) according to claim 14 by (x) melt-mixing of the matrix polymer (I), and (y) addition and homogeneous dispersion of the filler material (II) to the melt.

25. A shaped article comprising the TCP resin composition (i) or (ii) according to claim 14 formed by injection molding, extrusion, compression forming, vacuum forming, or blow molding.

26. A method of using the shaped article according to claim 25 for surfaces for automobile interior, motor housings, lamp housings and electrical and electronic housings or as heat sinks for high performance electronics or LED sockets.

Description

EXAMPLES

Materials:

Component (I):

[0200] ABS/PA Blend: Terblend N NM-21EF (UV-stabilized ABS/PA blend with high impact toughness, excellent flowability and enhanced heat resistance, Styrolution, Frankfurt, Germany).

[0201] Elastomeric block copolymer: Styroflex 2G 66 from Styrolution (Frankfurt, Germany), a linear styrene-butadiene triblock copolymer (SBC) of the structure S-(S/B)-S, the amount of the monomers in the total block copolymer is 35% by weight of butadiene and 65% by weight of styrene; the weight ratio of the blocks is 16/68/16; MFI: 14 (200 C./5 kg) g/10 min.

[0202] ABS: Terluran HI-10 (high impact, medium flow, injection molding and extrusion grade ABS of Styrolution, Frankfurt).

Component (II):

[0203] aluminosilicate: Silatherm Grade: 1360-400 MST (source: Quarzwerke Frechen), a natural occurring aluminosilicate treated with methacrylsilane, D.sub.50=5 m (D.sub.10=1 m, D.sub.90=16 m), density: 3.65 g/cm.sup.3
Boron nitride (BN): Mixed platelets, agglomerates, D.sub.50=16 m, density: 2.2 g/cm.sup.3 (Boron nitride CFX1022 from Momentive Performance Materials Inc., USA).
Graphite: natural occurring graphite flakes, up to 325 mesh, density: 2.26 g/cm.sup.3, 99.8% purity (source: Alfa Aesar GmbH & Co KG, Germany).
MWNT: Multiwall (Carbon) Nanotubes, average diameter 9.5 nm, average length 1.5 m, density: 2.2 g/cm.sup.3, purity: 90% carbon (source: Nanocyl S.A., NC 7000MWCNT)

[0204] The TCP resin compositions were prepared by mixing and compounding matrix polymer A and filler material B with Haake Rheomix 600p (time: 30 min at 30 rpm, Temp. 220 C. for SBC, 240 C. for ABS, 250 C. for ABS/PA-Blend).

[0205] Samples from the obtained TCP resin compositions were prepared by hot pressing with a Carver compression molding machine 25-12-2HC

[0206] Procedure for sample preparation for measurement of the thermal conductivity with Carver heated press 25-12-2HC

[0207] Compound lumps received from the kneader Haake Rheomix 600p are placed in the middle of a sandwich consisting of a metal plate, a release foil (e.g. glass fabric enhanced PTFE), a metal spacer (1 mm thickness) for adjusting the thickness of the resultant sample, again a release foil and a metal plate. This sandwich is preheated in the Carver heated press 25-12-2HC (220-250 C. depending on utilized polymer) without applied pressure for 2 min to 4 min (depending on the time needed for softening of the respective compound). After the material has softened a pressure of 6 metric tons is applied to the sandwich for 1 min. Afterwards the sandwich is removed and placed in a water cooled press for re-cooling with an applied force of 8 kN. Finally a 1 mm thick sample piece is received for investigation of the thermal conductivity.

Measurement Methods:

[0208]
Thermal conductivity =.Math.c.sub.p.Math.: [0209] thermal diffusivity : determined by Laser flash analysis (XFA 500 XenonFlash apparatus (Linseis) with an InSb infrared detector) through-plane measurement, Temp. 25 C. under air [0210] specific heat c.sub.p was determined by DSC (TA Instruments Q1000 DSC), 20 K/min, 50 ml/min N2, 10 to 30 mg sample, ASTM E1269 [0211] temperature program: [0212] 1. slope set to 200 to 215 C. [0213] 2. isotherm for 10 minutes [0214] 3. slope set to minus 40 C. [0215] 4. isotherm for 10 minutes [0216] 5. slope set to 200 to 215 C. [0217] density is determined by Buoyancy Balance (Mettler Toledo AG245)

[0218] Table 1 shows inventive TCP resin compositions (ii) with an aluminosilicate as filler material (II) in Styroflex 2G66 as matrix polymer (I).

[0219] The amount of the filler material (II) is based on the sum of components (I) and (II) which totals 100% by volume.

TABLE-US-00001 TABLE 1 Filler thermal heat Thermal Material (II) diffusivity Density capacity conductivity Exp. No. Vol % cm.sup.2/s g/cm.sup.3 J/g*K W/m*K Not in- 30.3 0.00196 1.733 1.111 0.378 ventive 1 40.3 0.00296 1.985 1.011 0.596 2 53.6 0.00556 2.29 0.928 1.182

[0220] The data presented in Table 1 show that the inventive TCP resin compositions (ii) show a significantly improved thermal conductivity in comparison to not inventive TCP resin compositions.

[0221] Table 2 shows inventive TCP resin compositions (i) with Styroflex 2G66 as matrix polymer (I) and a filler material (II), a mixture of an aluminosilicate as component (II-1) and graphite (examples 6 to 8) or MWNT (examples 3 to 5) as component (II-2). The sum of components (I) and (II) totals 100% by volume.

TABLE-US-00002 TABLE 2 total Filler (II) Volume Thermal heat Thermal Exp. (II-1) + (II-2) Ratio Component diffusivity Density capacity conductivity No. Vol % (II-1):(II-2) (II-2) cm.sup.2/s g/cm.sup.3 J/g*K W/m*K 3 40.3 30:1 MWNT 0.00360 2.02 1.106 0.803 4 40.3 10:1 MWNT 0.00402 1.9788 1.092 0.868 5 40.3 5:1 MWNT 0.00492 1.9266 1.038 0.983 6 40.3 30:1 Graphite 0.00288 2.0097 1.060 0.613 7 40.3 10:1 Graphite 0.00301 1.9876 1.106 0.661 8 40.3 5:1 Graphite 0.00323 1.9439 1.023 0.643

[0222] Table 3 shows inventive TCP resin compositions (i) with Terblend N NM21-EF as matrix polymer (I) and a filler material (II), a mixture of an aluminosilicate as component (II-1) and boron nitride as component (II-2). The sum of components (I) and (II) totals 100% by volume.

TABLE-US-00003 TABLE 3 total TiO.sub.2 Filler (II) Volume Component Thermal heat Thermal Exp. (II-1) + (II-2) Ratio component (III) diffusivity Density capacity conductivity No. Vol % (II-1):(II-2) (II-2) wt-% cm.sup.2/s g/cm.sup.3 J/g*K W/m*K 9 28.8 0.18:1 BN CFX1022 1 0.00646 1.834 0.919 1.089 10 29.8 0.35:1 BN CFX1022 1 0.00469 1.855 0.936 0.813

[0223] The data in Tables 2 and 3 show that graphite, MWNT and BN act synergistically with the aluminosilicate. The inventive TCP resin compositions (i) with Styroflex 2G66 as matrix polymer (I) and a mixture of an aluminosilicate as component (II-1) and graphite as component (II-2) (examples 6 to 8), MWNT (examples 3 to 5) or BN (examples 9 to 10) as component (II-2) show a synergistically improved thermal conductivity in comparison to the composition of example 1.

Examples 11 to 14

[0224]

TABLE-US-00004 TABLE 4 TCP resin compositions Exp. Component Component Component Additive No. (I) (II-1) (II-2) (III) 11 46 vol.-% 54.0 vol.-% ABS/PA- aluminosilicate, blend (80 wt.-%) 12 60 vol.-% 36.4 vol.-% BN 3.6 vol.-% 2 wt.-% TiO.sub.2 ABS (64.1 wt.-%) aluminosilicate, (5.9 wt.-%) 13 60 vol.-% 36.4 vol.-% BN 3.6 vol.-% 2 wt.-% TiO.sub.2 ABS/PA- (63.4 wt.-%) aluminosilicate blend (5.9 wt.-%) 14 60 vol.-% 36.4 vol.-% BN 3.6 vol.-% 2 wt.-% TiO.sub.2 SBC (64.7 wt.-%) aluminosilicate (6.0 wt.-%)

[0225] The amount of the additive (III) is based on the entire resin composition.

[0226] The TCP resin composition (ii) of Example 11 was produced using a MKS-30 Buss kneader with a Scheer SGS 25-E4 granulator. The total throughput was 4.25 kg/h, the speed was 70 rpm, the granulator feed was 50 m/min, the feed was in zone 1, the temperature was between 290 C. (zones 1 to 3), 280 C. (zone 4) and 265 C. (zones 5 to 8).

[0227] The TCP resin compositions (i) of Examples 12 to 14 have been prepared by use of a ZSK26Mcc (D=26 mm, L/D=44) twin-screw extruder (Coperion GmbH, Germany). Due to the high filler level a special dosing apparatus was used according to the Feed Enhancement Technology (FET) (melt temperature: 272 C./285 C./242 C., total throughput: 20/25/20 kg/h, melt pressure: 16/15/24 bar, screw speed: 250/350/250 1/min, temperature (zones 1 to 12): 250 C./220 C./260 C. (all data refer to examples 12/13/14 in this order)).

Mechanical Characterization

[0228] Injection molding of dog bones (170 mm*10 mm*4 mm) and Charpy samples (80 mm*10 mm*3 mm) with Arburg 320 S Allrounder 500-150
(T(melt): 220 C. (example 14), 260 C. (example 12), 270 C. (examples 11, 13);
T(mold): 50 C. (example 14), 80 C. (example 12, Charpy sample); 95 C. (dog bones, examples 12, 13), 120 C. (example 11). [0229] un-notched Charpy impact strength was determined according to ISO 179/1eU [0230] Impact pendulum Zwick/Roell RKP 5113 (50 J hammer)

[0231] Tensile test: E-modulus was determined according to DIN EN ISO 527

[0232] Test of tensile properties such as Tensile modulus (=E-modulus), Breaking stress and Breaking strain with Universal testing machine Zwick Z020 with macro displacement transducer (speed for tensile modulus: 1 mm/min; rest of test: 50 mm/min).

[0233] Sample plates (70 mm*70 mm*4 mm) were used to determine thermal conductivity (determination as described above); injection molding was done under the following conditions: [0234] Example 11: machine: Battenfeld, screw diameter 45 mm;

[0235] T(melt) 270 C., T(mold) 90 C., injection speed 75 cm.sup.3/s, melt pressure 100 bar, packing pressure 1650 bar/10 s, cooling time 35 s [0236] Examples 12/13/14: machine: Engel e-mac 50, screw diameter 30 mm; [0237] T(melt) 260 C./260 C./220 C. T(mold) 90 C./90 C./50 C., injection speed 100/95/75 cm.sup.3/s, melt pressure 100/100/100 bar, packing pressure 950 bar/10 s//950 bar/12/s//750 bar/10 s, cooling time 25/20/25 s (all data refer to examples 12/13/14 in this order)).

[0238] Flow Curve and Shrinkage Evaluation [0239] Instrument: Rheograph 6000 (Gottfert) [0240] Measurement parameters: Temperature selected based on polymer: [0241] Styroflex 2G66 (200 C.) [0242] Terluran HI10 (250 C.) [0243] Terblend N (250 C.) [0244] Procedure [0245] a) Measurement of the flow curve. This gives the actual shear rate for the utilized dye geometry (30 mm length, 1 mm diameter) and the selected two piston speeds during the melt density measurements. [0246] b) Measurement of the melt density: [0247] The column of the capillary rheometer is filled with the respective material, compressed by the stamp followed by a temperature equilibration. Afterwards the material is extruded through the die with the respective piston speeds. During the extrusion several material samples extruded between different fill levels are collected. With the known extruded fill level height and the column diameter the extruded volume is known. Together with the weight of the extruded sample the density in the molten state under the respective actual shear in the column is received. [0248] Calculation of Shrinkage:

[00001]$\mathrm{Shrinkage}.Math.\left[\frac{}{}\right]-\frac{\mathrm{density}.Math..Math.\left(\mathrm{RT}\right)-\mathrm{density}.Math..Math.\left(\mathrm{melt}\right)}{\mathrm{density}.Math..Math.\left(\mathrm{RT}\right)}*100.Math.\%$

[0249] The Melt Volume Rate (MVR) was measured according to DIN EN ISO 1133-1:2012-03.

[0250] Vicat Softening Temperature (VST B50): 50 N load, heating rate 50 K/h, DIN ISO 306

TABLE-US-00005 TABLE 5 Thermal properties: Thermal Heat Exp. kappa diffusity capacity No. [W/mK] [cm.sup.2/s] [J/gK] 11 1.664 0.00742 0.932 12 0.968 0.00556 0.812 13 1.579 0.00797 0.914 14 0.991 0.00486 0.952

TABLE-US-00006 TABLE 6 Mechanical properties MVR specific volume Charpy Tensile Breaking Breaking 250/21.6 resistivity Exp. unnotched modulus stress strain Shrinkage Density [ml/10 VST B50 DIN IEC 60093 No. [kJ/m.sup.2] [Mpa] [Mpa] [%] [%] [g/cm.sup.3] min] [ C.] [Ohm*m] 11 10 11700 56.6 0.78 2.408 184.7 2.13E+14 12 3.59 8960 33.2 0.4 2.9 2.142 0.05 94.9 2.57E+15 13 3.62 9280 40 0.5 3.8 2.165 1.74 1.56E+14 14 46.46 134 5.47 120 2.140 1.24E+15

Results:

[0251] Examples 11 to 14 show that TCP according to the present invention can be produced using different styrenic polymers as matrix. All examples in Table 5 show high thermal conductivity. Further Table 6 shows that a broad secondary property (e.g. Charpy unnotched, tensile modulus, MVR, VST) profile is possible, while retaining high thermal conductivity. In addition examples 11 to 14 have high specific volume resistivity as expected for electrically insulating materials. The observed shrinkage in case of example 12 and 13 is lower compared to commercially available TCPs (above 6), which is beneficial for injection molding applications.