Hydrothermal treatment of renewable raw material

Abstract

The present invention relates to a particulate carbon material that can be produced from renewable raw materials, in particular from biomass containing lignin, comprising: a 14C content that corresponds to that of the renewable raw materials, said content being preferably greater than 0.20 Bq/g carbon, especially preferably greater than 0.23 Bq/g carbon, but preferably less than 0.45 Bq/g carbon in each case; a carbon content in relation to the ash-free dry substance of between 60 ma. % and 80 ma. %; an STSA surface area of the primary particles of at least 5 m2/g and at most 200 m2/g; and an oil absorption value (OAN) of between 50 ml/100 g and 150 ml/100 g. The present invention also relates to a method for producing said carbon material and to the use thereof.

Claims

1. A multi-stage method for the hydrothermal treatment of a renewable raw material, the method comprising: providing a liquid containing the renewable raw material; subjecting the liquid containing the renewable raw material to a hydrothermal treatment at a temperature between 150° C. and 250° C.; substantially separating solid present after the hydrothermal treatment from the liquid; and removing residual moisture of the solid by drying, whereby a particulate carbon material is obtained; wherein a statistical thickness surface area (STSA) and an oil absorption number (OAN) of the particulate carbon material obtained while removing the residual moisture are controlled by mutually adjusting: a concentration of organic dry matter of the renewable raw material in the liquid containing the renewable raw material, a pH value of the liquid containing the renewable raw material, a concentration of inorganic ions in the liquid containing the renewable raw material, the temperature of the hydrothermal treatment, and a residence time of the hydrothermal treatment, in such a way that the particulate carbon material comprises: the STSA in a range between 5 m.sup.2/g and 200 m.sup.2/g and the OAN in a range between 50 ml/100 g and 150 ml/100 g.

2. The method according to claim 1, wherein the concentration of inorganic ions in the liquid containing the renewable raw material is determined by measuring conductivity of the liquid containing the renewable raw material.

3. The method according to claim 1, wherein the particulate carbon material is produced by mutual coordination of conditions of the hydrothermal treatment.

4. The method according to claim 1, wherein: the temperature and residence time of the hydrothermal treatment are adjusted while subjecting the liquid containing the renewable raw material to the hydrothermal treatment, so as to achieve the STSA in the range between 5 m.sup.2/g and 200 m.sup.2/g and the OAN in the range between 50 ml/100 g and 150 ml/100 g; and the method further includes: obtaining a slightly higher concentration of inorganic ions than is initially obtained after the adjusting of the concentration of the organic dry matter and the pH value, and subsequently effecting a further increase of the concentration of inorganic ions by addition of salts, until the concentration of inorganic ions, as measured by the conductance, appropriate for the process conditions of the hydrothermal treatment is achieved.

5. The method according to claim 1, wherein the adjustment adjusting of the concentration of the organic dry matter of the renewable raw material in the liquid containing the renewable raw material, of the pH value of the liquid containing the renewable raw material, and/or of the concentration of inorganic ions in the liquid containing the renewable raw material is effected while providing a-the liquid containing the renewable raw material.

6. The method according to claim 1, wherein the adjustment adjusting of the concentration of the organic dry matter of the renewable raw material in the liquid containing the renewable raw material, of the pH value of the liquid containing the renewable raw material, and/or of the concentration of inorganic ions in the liquid containing the renewable raw material is effected while providing a-the liquid containing the renewable raw material and while subjecting the liquid containing the renewable raw material to the hydrothermal treatment.

7. The method according to claim 1, wherein the adjustment adjusting of the concentration of the organic dry matter of the renewable raw material in the liquid containing the renewable raw material, of the pH value of the liquid containing the renewable raw material, and/or of the concentration of inorganic ions in the liquid containing the renewable raw material is effected while subjecting the liquid containing the renewable raw material to the hydrothermal treatment.

8. The method according to claim 6 wherein: providing the liquid containing the renewable raw material comprises completely dissolving the renewable raw material in the liquid containing the renewable raw material; and subjecting the liquid containing the renewable raw material to the hydrothermal treatment comprises: forming desired finely divided particles, by not only chosen process conditions of the hydrothermal treatment, but in addition by: an increase of a concentration of organic dry matter of the renewable raw material in the liquid containing the renewable raw material, a decrease of a pH value of the liquid containing the renewable raw material, or an increase of a concentration of inorganic in the liquid containing the renewable raw material.

9. The method according to claim 8, further comprising, after completion of formation of desired finely divided particles: decreasing the concentration of the organic dry matter in the liquid containing the particulate carbon material, increasing the pH value of the liquid containing the particulate carbon material, or decreasing the concentration of the inorganic ions in the liquid containing the particulate carbon material.

10. The method according to claim 1, wherein the STSA and the OAN of the particulate carbon material are controlled by adjusting: the concentration of the organic dry matter of the renewable raw material in the liquid containing the renewable raw material to a value between 5 wt-% and 40 wt-%, the pH value of the liquid containing the renewable raw material at 20° C. to 25° C. to a value ≥7, the concentration of inorganic ions in the liquid containing the renewable raw material p to a value between 10 mS/cm and 200 mS/cm, the temperature of the hydrothermal treatment to a maximum value between 200° C. and 250° C. and/or the residence time in the hydrothermal treatment to a period between 1 minute and 6 hours.

11. The method according to claim 1, wherein: the renewable raw material is lignin; a concentration of organic dry matter of the liquid containing lignin in in a range between 10 wt-% and 20 wt-%, a pH value of the liquid containing lignin in a range between 8.5 and 10.5, a concentration of inorganic ions of the liquid containing lignin is such that conductivity of the liquid is in a range between 10 mS/cm and 25 mS/cm, a maximum temperature of the hydrothermal treatment is in a range between 210° C. and 240° C., and residence time of the liquid containing lignin in the hydrothermal treatment is in a range between 120 and 240 minutes, whereby: particulate carbon material thus produced, measured after the solid is substantially separated from the liquid and the residual moisture is dried, has an STSA in a range between 5 m.sup.2/g and 50 m.sup.2/g and an OAN in a range between 50 ml/100 g and 100 ml/100 g.

12. The method according to claim 1, wherein the renewable raw material is completely dissolved in the liquid containing the renewable raw material.

13. The method according to claim 1, wherein: the renewable raw material is not completely dissolved in the liquid containing the renewable raw material; and the method further comprises adjusting at least one of the following parameters, such that, due to a temperature increase during the hydrothermal treatment, the renewable raw material initially is dissolved completely prior to the solid being generated in the hydrothermal treatment: the concentration of organic dry matter of the renewable raw material in the liquid containing the renewable raw material, the pH value of the liquid containing the renewable raw material, and the concentration of inorganic ions in the liquid containing the renewable raw material.

14. The method according to claim 1, wherein: the method is operated continuously, process conditions of the hydrothermal treatment are kept constant, and a continuous adjustment of a pH value and conductance of the liquid containing the renewable raw material as the liquid is provided.

15. The method according to claim 1, wherein the STSA is increased by: decreasing the concentration of the organic dry matter of the renewable raw material in the liquid containing the renewable raw material, and/or increasing the pH value of the liquid containing the renewable raw material, and/or decreasing the concentration of inorganic ions in the liquid containing the renewable raw material.

16. The method according to claim 1, wherein the STSA is decreased by: increasing the concentration of the organic dry matter of the renewable raw material in the liquid containing the renewable raw material, and/or decreasing the pH value of the liquid containing the renewable raw material, and/or increasing the concentration of inorganic ions in the liquid containing the renewable raw material.

Description

(1) The present invention will subsequently be explained in detail with reference to exemplary embodiments. In the drawing:

(2) FIG. 1 shows a diagram of the stress-strain distribution in the tensile test as an example for the rubber-technological characteristic values of cross-linked rubber articles made of SBR with the particulate carbon material according to the invention and of the associated reference.

(3) FIG. 2 shows a diagram of the curves of the loss factor tan delta (logarithmic scaling) in dependence on the temperature at completely cross-linked articles made of SBR with the particulate carbon material according to the invention and at the reference with N 660, respectively.

(4) FIG. 3 shows a diagram of the stress-strain distribution in the tensile test as a comparison of the rubber-technological characteristic values of cross-linked rubber articles made of SBR, which are provided with untreated lignin, with the particulate carbon material according to the invention, but without a coupling reagent, and with the particulate carbon material according to the invention and a coupling reagent.

(5) FIG. 4 shows a diagram of the stress-strain distribution in the tensile test as a comparison of the rubber-technological characteristic values of cross-linked rubber articles made of SBR, which are provided with particulate carbon material according to the invention, but without any further additive, with the particulate carbon material according to the invention and a reagent for masking the functional groups, and with the particulate carbon material according to the invention and a coupling reagent.

(6) FIG. 5 shows a diagram of the stress-strain distribution in the tensile test as a comparison of the rubber-technological characteristic values made of elastomer material mixtures based on natural rubber and butadiene rubber NR/BR and the particulate carbon material, each with different mixing procedures, and of the reference,

(7) FIG. 6 shows a diagram of the stress-strain distribution in the tensile test as a comparison of the rubber-technological characteristic values of cross-linked rubber articles made of SBR, which are provided with the particulate carbon material according to the invention without a coupling reagent, and of the reference.

(8) The exemplary embodiments describe the method according to the invention for obtaining the particulate carbon material according to the invention, its properties and its performance in the cross-linked rubber.

Examples 1-11 for Producing the Particulate Carbon Material from Lignin

(9) In a first step a liquid containing the renewable raw material is provided.

(10) Initially, water (1) and lignin (2) are mixed and a lignin-containing liquid with an adjusted content of organic dry matter (3) is prepared.

(11) The lignin subsequently is completely dissolved in the lignin-containing liquid. For this purpose, the pH value is adjusted to the desired value (7) by adding a base or an acid (6). The preparation of the solution is supported by intensive mixing at a suitable temperature (4) for a sufficient period (5). By the added base or acid and by salts that are added in addition (8) and/or also originate from the ash content of the lignin a particular concentration of inorganic ions is adjusted, which can be measured as conductivity (9). The composition and properties of the lignin-containing liquid thus prepared are indicated in Table 1

(12) TABLE-US-00001 TABLE 1 Example 1 2 3 4 5 6 7 8 9 — ml Type Type g % ° C. h Additive g — Additive g mS/cm 1 10200 distilled water Lignin 1 1800 14.1 80 2 NaOH 107.25 10.1 — 0.0 15.1 2 10200 distilled water Lignin 1 1800 14.1 80 2 NaOH 128.40 10.3 — 0.0 17.5 3 10200 distilled water Lignin 2 1800 14.2 80 2 NaOH 111.60 10.2 — 0.0 18.1 4 10200 distilled water Lignin 2 1800 14.2 80 2 NaOH 111.60 10.2 — 0.0 20.1 6 3854 tap water Lignin 3 1092 14.8 80 2 NaOH 54.00 9.6 — 0.0 15.9 Ludwigsfelde 7 3854 tap water Lignin 3 1092 14.8 80 2 NaOH 54.00 9.6 — 0.0 15.9 Ludwigsfelde 8 3854 tap water Lignin 3 1092 14.8 80 2 NaOH 54.00 9.6 — 0.0 15.9 Ludwigsfelde 9 3854 tap water Lignin 3 1092 14.8 80 2 NaOH 54.00 9.6 — 0.0 15.9 Ludwigsfelde 10 3854 tap water Lignin 3 1092 14.8 80 2 NaOH 54.00 9.6 — 0.0 15.9 Ludwigsfelde 11 48.23 distilled water Lignin 1 20.9 14.1 80 2 NaOH 0.44 9.8 — 0.0 17.7

(13) The composition of the lignin used is indicated in Table 2.

(14) TABLE-US-00002 TABLE 2 Lignin 1 Lignin 2 Lignin 3 C 62.8 64.0 67.2 H 4.8 5.2 5.5 O (calculated) 24.8 24.0 24.0 N 0.3 0.0 0.0 S 1.3 1.5 1.8 Na 2.5 1.9 0.3 Ash (without Na) 3.6 4.1 1.2

(15) In the second step, the liquid containing the renewable raw material is subjected to a hydrothermal treatment and thus a solid is obtained.

(16) The solution prepared in the first step is heated from a starting temperature (10) for a heating time (11) to a reaction temperature (12) that is maintained for a reaction period (13). Subsequently, cooling for a cooling time (14) to an end temperature (15) is effected. As a result, a solid is obtained. In dependence on the aforementioned process conditions the pH value (16) and the conductivity (17) of the liquid containing the solid are changed.

(17) With an appropriate adjustment of the content of organic dry matter, the pH value and the concentration of inorganic ions in the first step, and an appropriate choice of the process conditions in the second step, conditions are obtained in the second step at which the particulate carbon material separates from the solution in a raw form. The process conditions of the second step are indicated in Table 3.

(18) TABLE-US-00003 TABLE 3 Example 10 11 12 13 14 15 16 17 — ° C. min ° C. min min ° C. — mS/cm 1 80 90 240 150 3600 80 9.0 19.7 2 80 90 240 150 3600 80 9.1 21.4 3 80 90 240 150 3600 80 8.6 20.2 4 80 90 240 150 3600 80 8.4 21.1 6 30 40 225 324 40 30 8.4 13.2 7 30 40 225 408 40 30 8.3 13.5 8 30 41 230 270 41 30 8.3 13.5 9 30 41 230 300 41 30 8.2 13.7 10 30 42 235 162 42 30 8.7 12.9 11 30 41 230 180 41 30 8.6 20.9

(19) In the third step, the raw particulate carbon material is dewatered and possibly washed. The raw particulate carbon material is largely separated from the liquid containing the same by a dewatering step (18). Subsequently, the raw particulate carbon material is washed with a multiple amount of water and dewatered again. The process conditions of the third step are summarized in Table 4.

(20) TABLE-US-00004 TABLE 4 19 Amount of washing liquid kg/kg of Example 18 dry particulate — Device Type Washing liquid carbon material 1 centrifuge; 6000 resuspension/centrifuge; 6000 distilled water 3 RPM/15 min RPM/15 min 2 centrifuge; 6000 resupension/centrifuge; 6000 3 RPM/15 min RPM/15 min 3 centrifuge; 6000 resuspension/centrifuge; 6000 3 RPM/15 min RPM/15 min 4 centrifuge; 6000 resuspension/centrifuge; 6000 3 RPM/15 min RPM/15 min 6 centrifuge; 9000 resuspension/centrifuge; 9000 tap water 2 RPM/15 min RPM/15 min Ludwigsfelde 7 centrifuge; 9000 resuspension/centrifuge; 9000 2 RPM/15 min RPM/15 min 8 centrifuge; 9000 resuspension/centrifuge; 9000 2 RPM/15 min RPM /15 min 9 centrifuge; 9000 resuspension/centrifuge; 9000 2 RPM/15 min RPM/15 min 10 centrifuge; 9000 resuspension/centrifuge; 9000 2 RPM/15 min RPM/15 min 11 centrifuge; 9000 resuspension/centrifuge; 9000 2 RPM/15 min RPM/15 min

(21) In the fourth step, the dewatered and possibly washed raw particulate carbon material is dried and possibly ground.

(22) The dewatered raw particulate carbon material and remaining liquid is dried at an elevated temperature (20, see Table 5), whereby the particulate carbon material is obtained. Subsequently, the particulate carbon material can be de-agglomerated (21, see Table 5).

(23) TABLE-US-00005 TABLE 5 Example 20 21 — ° C. — 1 105 jet mill with classifier wheel 2 105 jet mill with classifier wheel 3 105 jet mill with classifier wheel 4 105 jet mill with classifier wheel 6 105 — 7 105 — 8 105 — 9 105 — 10 105 — 11 105 —

(24) Quality of the obtained particulate carbon material from Examples 1-11: In the end, an expression of the particulate carbon material according to the invention is obtained (see Table 6):

(25) TABLE-US-00006 TABLE 6 Car- Oxy- bon gen Ash average D50/ Wt-% Wt-% con- sphere average Water dry, dry, tent OAN diam- sphere con- Exam- ash- ash- Wt-% STSA Value pH).sup.1 BB).sup.2 D/G).sup.3 D50).sup.4 D90).sup.4 D99).sup.4 eter ).sup.5 diameter BET tent ple free free dry m.sup.2/g ml/100 g — % — μm μm μm μm — m.sup.2/g % 1 72.3 21.7 4.9 17.7 94.4 8.7 9.8 0.52 1.6 3.1 4.4 0.23 7.0 19.9 0.8 2 71.9 22.3 4.6 12.6 80.5 8.5 9.5 0.65 1.5 2.8 4.0 0.32 4.7 14.2 1.9 3 70.9 22.8 5.3 13.6 84.1 8.8 n.d. n.d. 1.4 2.4 3.2 0.29 4.7 14.4 1.3 4 70.7 22.8 5.3 10.8 74.0 8.8 n.d. n.d. 1.5 2.6 3.3 0.37 4.1 10.0 1.5 6 69.5 n.d. n.d. 26.9 n.d. n.d. n.d. n.d. n d. n.d. n.d. 0.15 n.d. 28.3 1.5 7 89.8 n.d. n.d. 19.2 n.d. n.d. n.d. n.d. n.d. n.d. n.d. 0.21 n.d. 20.2 2.4 8 70.1 n.d. n.d. 14.0 n.d. n.d. n.d. n.d. n.d. n.d. n.d. 0.29 n.d. 14.7 1.3 9 70.2 n.d. n.d. 9.9 n.d. n.d. n.d. n.d. n.d. n.d. n.d. 0.40 n.d. 10.4 1.6 10 70.4 n.d. n.d. 2.6 n.d. n.d. n.d. n.d. n.d. n.d. n.d. 1.56 n.d. 2.7 2 11 70.3 n.d. n.d. 36.7 n.d. n.d. n.d. n.d. n.d. n.d. n.d. 0.11 n.d. 38.6 1.3 .sup.1= in 15% suspension; .sup.2= resistance to bases in % of the dissolved material; .sup.3= from the Raman spectrum; .sup.4= from the grain size determination by means of laser diffraction .sup.5= calculated from STSA and particle density; n.d. = not determined

Examples 12A-D and Reference Example for the Manufacture of Rubber Articles Made of SBR with the Particulate Carbon Material from Examples 1 and 2 or with Carbon Black N 660

(26) The carbon materials obtained according to the exemplary embodiments 1 and 2 are introduced into a rubber mixture as filler and vulcanized by means of further additives. The composition of the rubber mixture is shown in Table 7.

(27) TABLE-US-00007 TABLE 7 Reference A B C D Elastomer sSBR sSBR sSBR sSBR sSBR — type Elastomer 100 100 100 100 100 phr quantity Filler type N660 particulate particulate particulate particulate — carbon carbon carbon carbon material acc. material acc. material acc. material acc. to Ex. 2 to Ex. 2 to Ex. 1 to Ex. 2 Filler quantity 40 40 40 40 60 phr Coupling — — Si69 Si69 Si69 — reagent Type Coupling — — 3.2 3.2 4.8 phr reagent Quantity ZnO 3 3 3 3 3 phr Stearic acid 2 2 2 2 2 phr DPG 2 2 2 2 2 phr CBS 1.5 1.5 1.5 1.5 1.5 phr Sulfur 1.5 1.5 1.5 1.5 1.5 phr phr: parts per hundred rubber, quantity based on elastomer quantity DPG, CBS: vulcanization accelerator Si69: coupling reagent

(28) As SBR, solution SBR (sSBR) Buna VSL 4526-0 HM of Lanxess was used. It is a copolymer comprising 26 wt-% styrene beside butadiene. Its Mooney viscosity is 65 ME (ASTM D 1646). Zinc oxide, stearic acid and sulfur were obtained from Fischer Scientific. 2-N-cyclohexyl benzothiazole sulfenamide (CBS) was obtained from Lanxess. 1,3-Diphenylguanidine (DPG) was used from Sigma-Aldrich Co., LLC, USA. The process oil TDAE (VIVATEC 500) was obtained from Klaus Dahleke KG. The antioxidant 2,2,4-trimethyl-1,2-dihydroquinoline polymer TMQ was supplied by C.H.Erbslöh, Krefeld. N-(1,3-dimethylbutyl)-N′-phenyl-P-phenylenediamine (6PPD) was obtained from abcr GmbH & Co. K G, Karlsruhe. Bis(triethoxysilylpropyl)tetrasulfide was used as coupling reagent, which is sold by Evonik Industries under the name Si69®.

(29) SBR was placed in the internal mixer (Haake Rheomix 600P, ThermoFisher Scientific, Karlsruhe) at 145° C. and a fill factor of 0.7, corresponding to a volume of 56 cm.sup.3. Subsequently, the fillers were added in two stages. For the complete silanization, after possibly adding the silane Si69, the temperature in the internal mixer was kept in a range between 140-165° C. for 10 min and mixing was effected at a rotational speed of 60 min.sup.−1.

(30) The addition of the antioxidants and vulcanization additives was effected on a two-roller rolling mill (Polymix-110L, Servitec Maschinen Service GmbH, Wustermark) at a starting temperature of 50° C. and a constant friction of 1:1.2.

(31) The rubber mixtures Reference and A (Table 7) are cross-linked by using a vulcanization process customary for the application of carbon black. The rubber mixtures B, C and D (Table 7) are cross-linked by using a vulcanization process customary for the application of silica together with Si69. The samples were vulcanized in a laboratory press TP1000 (Fontijne Grotnes B. V., Vlaardingen, Netherlands) at 160° C. and a pressing force of 150 kN. The optimum vulcanization time t.sub.90 was determined by means of a Rubber Process Analyzer (Scarabaeus SIS-V50, Scarabaeus GmbH, Wetzlar).

(32) The mechanical characterization was made on DIN S2 test specimens according to DIN 53504 with a Zwick/Roell-Z010 materials testing machine (Zwick GmbH & Co KG, Ulm) with optical strain sensor at a crosshead speed of 200 mm/min at room temperature. The stress-strain distributions in the tensile test as an example for the rubber-technological properties of the obtained rubber articles from Examples A-D of Table 7 are indicated in the diagram of FIG. 1.

(33) In particular in the case of Examples B, C and D (in which a coupling reagent is added) the same show comparable properties as the filler N660. The values for the modulus 50%, modulus 100% and modulus 200% of Examples B and C are at least as high as for the Reference. Furthermore, it is shown that the increase of the filling degree from 40 phr (B) to 60 phr (D) of the particulate carbon material according to Example 2 at a strain in the lower range (up to 100%) leads to an increase of the stress values, i.e, of the modulus 50% and of the modulus 100%. In addition, it becomes clear that an increase of the STSA surface area and the OAN value of the particulate carbon material from the values of Example 2 to the values of Example 1 at the same filling degree leads to an improvement of the tensile strength and to higher values of the modulus 50%, modulus 100% and modulus 200% (compare B and C). Furthermore, it becomes clear that the particulate carbon material from Example 2 with its STSA surface area of 12.6 m.sup.2/g already shows a comparable stress-strain distribution in the tensile test as the classical carbon black N660, which is characterized by an STSA surface area of 34 m.sup.2/g±5 m.sup.2/g.

(34) The loss factor tan delta (quotient of loss modulus E″ and storage modulus E′ of the elastomer material) in dependence on the temperature, determined in a dynamic mechanical analysis (temperature sweep), is shown in FIG. 2 and Table 8.

(35) The mixtures with N660 (reference) and those with the particulate carbon material from Example 2 without coupling reagent (Example 12A) show similar glass transition temperatures (T.sub.g,SBR=−2.91° C.; see the peak of the curve tan delta vs. temperature in FIG. 2). These two mixtures also have a similar rigidity in the rubber plateau region above the glass transition temperature. The tan delta curves are close to each other, wherein the curve of the reference mixture from about 76° C. however is slightly lower than that of Example 12A and thus indicates a slightly lower energy loss.

(36) The use of the particulate carbon material from Example 2 in combination with a coupling reagent (Example 12B) leads to significant changes. As compared to Reference and 12A, the glass transition temperature of the mixture of Example 12B is shifted upwards to T.sub.g,SBR=−0.48° C. Under the conditions of a weak dynamic elongation (0.5%) the energy loss properties of the mixture 12B are distinctly improved with respect to the Reference with N660, which is revealed by the lower curve profile in the temperature range above the glass transition temperature.

(37) It can be seen that the elastomer material that contains the particulate carbon material from Example 2 and a coupling reagent has lower values as compared to the Reference with N660 for tan delta above the glass transition temperature, which allows a comparatively reduced rolling friction to be expected for a tire made of this material.

(38) TABLE-US-00008 TABLE 8 tan delta 60° C. tan delta 0° C. Reference N660 0.1020 1.4342 Example 12 A 0.1035 1.4023 Example 12 B 0.0840 1.6208

(39) FIG. 2 also reveals that the tan delta of Example 12B is higher at 0° C. than for the Reference, which allows an improved wet grip of a tire made of the mixture of Example 12B to be expected.

Comparative Example 13 for the Manufacture of Rubber Articles from SBR with Untreated Lignin

(40) According to the prior art, untreated lignin has already been used in rubber mixtures. The following comparative example shows the different effect of untreated lignin and of the carbon material according to the invention in a rubber mixture.

(41) Lignin 3 from Table 2 is introduced into a rubber mixture as filler for comparison and vulcanized by means of further additives. The composition of the rubber mixture corresponds to the composition in Example 12B, wherein however untreated lignin 3 now is used instead of the particulate carbon material from Example 2. The rubber mixture for Example 13 is cross-linked by using a vulcanization process customary for the application of silica together with Si69.

(42) The stress-strain distribution in a tensile test as an example for the rubber-technological properties of the obtained rubber article is indicated in the diagram of FIG. 3 together with the results of Example 12A and 12B.

(43) It can be seen that even when the coupling reagent silane Si69 is used, the effect in the rubber mixture caused by untreated lignin (Example 13) is distinctly weaker than the effect caused by the carbon material according to the invention as such (Example 12A) and quite particularly distinctly lags behind the effect of the carbon material according to the invention in combination with silane Si69 (Example 12B).

Example 14 for the Determination of the .SUP.14.C Content in the Product of Example 2

(44) For the purpose of determining the .sup.14C content the material of Example 2 was supplied to the Poznań Radiocarbon Laboratory, Foundation of the A. Mickiewicz University, ul. Rubież 46, 61-612 Poznań. The used method is described by the head of the laboratory, Tomasz Goslar, on the Internet site of the institute. The contents essential for lignin are summarized below.

(45) Procedure for .sup.14C dating by means of AMS technology with the following steps:

(46) chemical pretreatment

(47) production of CO.sub.2 and graphitization

(48) .sup.14C measurement by AMS

(49) calculation and calibration of the .sup.14C age

(50) The methods of the chemical pretreatment are described in principle in Brock et al., 2010, Radiocarbon, 52, 102-112.

(51) Samples of plant residues are treated with 1 M HCl (80° C, 20+ min), 0.025-0.2 M NaOH (80° C) and then with 0.25 M HCl (80° C., 1 h). After treatment with each reagent, the sample is washed with deionized water (Millipore) to pH=7. For the first HCl treatment a longer period (20+) is used, when the sample still reveals the development of gas bubbles. The step of the NaOH treatment is repeated several times, in general until no more coloration of the NaOH solution occurs (the coloration of the solution is caused by humic acids dissolved in NaOH), but the NaOH treatment is stopped when there is a risk of the complete dissolution of the sample.

(52) In the case of organic samples the CO.sub.2 is produced by combustion of the sample.

(53) The combustion of the sample is carried out in the closed quartz tube (under vacuum) together with Cu© and Ag wool at 900° C. for 10 hours. The obtained gas (CO.sub.2+steam) then is dried in a vacuum apparatus and reduced with hydrogen (H.sub.2) by using 2 mg of Fe powder as catalyst. The obtained mixture of carbon and iron then is pressed into a special aluminum holder corresponding to the description of Czernik J., Goslar T., 2001, Radiocarbon, 43, 283-291. In the same way, the standard samples are produced, e.g. samples that contain no .sup.14C (coal or IAEA C1 Carrara marble) and samples of the “International modern .sup.14C standard” (oxalic acid II).

(54) The measurements described here are carried out in the AMS .sup.14C laboratory of A. Mickiewicz University in Poznań.

(55) The content of .sup.14C in the carbon sample is measured with the spectrometer “Compact Carbon AMS” (manufacturer: National Electrostatics Corporation, USA), which is described in the article Goslar T., Czernik J., Goslar E., 2004, Nuclear Instruments and Methods B, 223-224, 5-11. The measurement is based on the comparison of the intensities of the ion beams of .sup.14C, .sup.13C and .sup.12C, which are measured for each sample and each standard (modern standard: “oxalic acid II” and standard for carbon free from .sup.14C (“background”). In each AMS run 30-33 samples of unknown age are measured in alternation with 3-4 measurements of the modern standard and 1-2 background measurements. When organic samples are dated, the background is represented by coal.

(56) Conventional .sup.14C age is calculated by using the correction for the isotope fractionation (according to Stuiver, Polach 1977, Radiocarbon 19, 355), based on the ratio .sup.13C/.sup.12C which is determined in the AMS spectrometer simultaneously with the ratio .sup.14C/.sup.12C (note: the measured values of δ.sup.13C depend on the isotope fractionation during the CO.sub.2 reduction and the isotope fractionation within the AMS spectrometer, and as such they cannot be compared with the values δ.sup.13C that are determined for gas samples with conventional mass spectrometers). The uncertainty of the calculated .sup.14C age is determined by means of the uncertainty resulting from the count statistics, likewise the scattering (standard deviation) of the individual .sup.14C/.sup.12C results. The uncertainties of the .sup.14C/.sup.12C ratios measured for the standard samples are additionally taken into account. The 1-sigma uncertainty of the conventional .sup.14C age, which is indicated in the report, is the best approximation of the absolute uncertainty of the measurement.

(57) The calibration of the .sup.14C age is carried out with the program OxCal ver. 4.2 (2014) the fundamentals of which are described in Bronk Ramsey C., 2001, Radiocarbon, 43, 355-363, while the current version is described in Bronk Ramsey C., 2009, Radiocarbon, 51, 337-360 and Bronk Ramsey C. and Lee S., 2013, Radiocarbon, 55, 720-730. The calibration is made against the latest version of the .sup.14C calibration curve, i.e. INTCAL13 (Reimer P. J., et al. 2013, Radiocarbon, 55(4), 1869-1887).

(58) The analysis provides the age of the carbon sample for archaeological purposes. The measurement result however can also be indicated as the specific activity. In the present case of the material of Example 2, the analysis provided a value of 243.30±0.52 Bq/kgC or Bq/kg of carbon for the specific activity.

Example 15 for the Manufacture of Rubber Articles from SBR with the Particulate Carbon Material of Example 2 in the Presence of a Reagent Masking Functional Groups

(59) The carbon material obtained according to exemplary embodiment 2 is introduced into a rubber mixture as filler and vulcanized by means of further additives. The composition of the rubber mixture and its processing corresponds to that of Example 12B (Table 7), wherein however the silane Si69 is replaced in equimolar proportion by triethoxymethylsilane, which corresponds to a use of 1.06 phr. The further processing also is analogous to Example 12.

(60) The triethoxymethylsilane is not able to be incorporated into the cross-linkage via sulfur bridges. However, it reacts with the surface of the carbon material according to the invention by consuming the functional groups. The functional groups reacting with the silane are outwardly replaced by methyl groups, which as compared to the non-modified starting material leads to a compatibilization of the filler surface with the non-polar rubber matrix.

(61) The carbon material according to the invention treated with triethoxymethylsilane for example effects a higher tensile strength in the rubber as compared to the carbon material used without silane, but as expected lags behind the carbon material in combination with the coupling silane Si69.

(62) The stress-strain distribution in a tensile test as an example for the rubber-technological properties of the obtained rubber articles of FIG. 4 shows that in selected rubber systems and for selected applications it may be expedient to perform a masking of the functional groups.

Examples 16 A and B as Well as Reference for the Manufacture of Rubber Articles from NR/BR with the Particulate Carbon Material of Example 2 or with Carbon Black N660:

(63) The carbon material obtained according to exemplary embodiment 2 is introduced as filler into a mixture of NR and BR and vulcanized by means of further additives.

(64) In the case of A and the Reference a mixture (pre-mix) of NR and BR initially is prepared in the internal mixer (Haake Rheomix 600P, ThermoFisher Scientific, Karlsruhe) at a starting temperature of 120° C., which then is mixed with the respective filler and further components. In the case of B by contrast a master batch of BR, the filler and silane initially is prepared in the internal mixer (starting temperature 35° C., rotational speed 60 min.sup.−1), which subsequently is further processed with NR and the remaining components (likewise in the internal mixer, starting temperature 120° C., rotational speed 60 min.sup.−1). The quantity composition of both processing variants is identical.

(65) The stress-strain distributions in the tensile test as an example for the rubber-technological properties of the obtained rubber articles from Examples A and B are indicated in the diagram of FIG. 5. The same show that in NR/BR mixtures the carbon material according to the invention can be used for reinforcement. Furthermore, it can be seen that the order of processing has an influence on the performance of the filler in the articles made of the respective NR/BR rubber mixture in the cross-linked condition. In this way, modulus and tensile strength can be influenced.

Examples 17 A and B as Well as Reference for the Manufacture of Rubber Articles from NBR by Using the Particulate Carbon Material of Example 4 or N 990

(66) The carbon material obtained according to exemplary embodiment 4 is introduced into NBR as filler and vulcanized by means of further additives, but without a coupling reagent. The composition of the rubber mixture is shown in Table 9.

(67) TABLE-US-00009 TABLE 9 Reference A B Perburan 3945 100.0 100.0 100.0 ZnO 5.0 5.0 5.0 Stearic acid 1.0 1.0 1.0 Mesamoll II 15.0 15.0 15.0 Talc 80.0 80.0 80.0 N 500 30.0 30.0 30.0 N 990 80.0 40.0 Material of Example 4 40.0 80.0 Vulkanox 4010 3.0 3.0 3.0 Sulfur 0.5 0.5 0.5 MBTS 1.0 1.0 1.0 TMTD 3.0 3.0 3.0

(68) The mixtures are prepared on a Haake Rheomix 600 (tangential rotor geometry, 78 cm.sup.3) with a starting temperature of 40° C. and a rotor speed of 100 min.sup.−1. Initially, the NBR polymer is mixed for 2 min, then in addition stearic acid, ZnO, possibly material from Example 4 and talcum for 2 min, in addition possibly N990 and Mesamoll II for another 4 min, antioxidants for another 3 min, and the vulcanization chemicals for another 2 min. The optimum vulcanization time was determined by means of a Rubber Process Analyzer and the mixture was vulcanized at 160° C. for a minute value of (t.sub.90+1/mm of layer thickness).

(69) The determination of the Shore A hardness was effected according to DIN 53505; 2000-08, the tensile test according to DIN 53504:2009-10, and the storage for 72 h at 70° C. in oil Lubrizol OS 206304 according to DIN ISO 1817:2008-08.

(70) The values shown in Table 10 were obtained.

(71) TABLE-US-00010 TABLE 10 Example Reference A B Shore A hardness 83 84 85 Tensile strength (MPa) 9.9 11.1 11.4 Elongation at break (%) 235 253 248 Modulus (MPa) 50% 4.7 5.3 5.6 100% 6.6 7.5 8.0 200% 9.7 10.8 11

(72) It becomes clear that both with a partial and with a complete replacement of N 990 by the carbon material according to the invention of Example 4 without the addition of a coupling reagent, comparable or even slightly improved values are achieved in the tensile test, see FIG. 6. The same applies for the variations of the values after storage in oil as shown in Table 11. When replacing inactive carbon blacks such as N 990, the use of the carbon material according to the invention in its quality according to Example 4 without a coupling reagent is sufficient to achieve comparable values.

(73) TABLE-US-00011 TABLE 11 Changes after storage in engine oil 72 h/70° C. Reference A B in the weight % −2.6 −2.6 −2.7 in the volume % −3.4 −3.3 −3.3 in the hardness +3 +3 +3 in the tensile strength % +6 +12 +11 in the elongation at break % −9 −6 −10