Method for preparing aluminosilicate particles having excellent dispersion, reinforcing material for rubber comprising the aluminosilicate particles, and rubber composition for tires comprising the reinforcing material

Abstract

The present disclosure relates to a method for preparing aluminosilicate particles having excellent dispersion, a reinforcing material for rubber including the aluminosilicate particles, and a rubber composition for tires including the same. The reinforcing material for rubber including the aluminosilicate particles prepared by the method of the present disclosure can exhibit excellent dispersibility in the rubber composition and an enhanced reinforcing effect, so that it can be suitably used in eco-friendly tires requiring high efficiency and high fuel efficiency.

Claims

1. A method for preparing aluminosilicate particles, comprising: curing a raw material mixture to obtain a solid product including aluminosilicate particles, wherein the raw material mixture comprises a basic or alkaline aqueous solution, a silicon source, and an aluminum source; washing the solid product; purifying the washed solid product to separate the aluminosilicate particles from unreacted silicon and aluminum sources, wherein the purification comprises: dispersing the washed solid product in distilled water; precipitating the unreacted silicon and aluminum sources base on weight difference; obtaining a supernatant having the aluminosilicate particles; and drying the supernatant to obtain the aluminosilicate particles.

2. The method for preparing aluminosilicate particles of claim 1, wherein the silicon source is at least one compound selected from the group consisting of fumed silica, rice husk, colloidal silica, cellite, pearlite, rice husk ash, silica fume, organosilane, clay, minerals, meta kaolin, calcined clay, active clay, fly ash, slag, pozzolan, glass powder, and red mud; and the aluminum source is at least one compound selected from the group consisting of alumina, aluminate, aluminum salt, organic aluminoxane, pearlite, clay, mineral, meta kaolin, calcined clay, active clay, fly ash, slag, pozzolan, glass powder, and red mud.

3. The method for preparing aluminosilicate particles of claim 1, wherein the curing is carried out at a temperature of 20 to 90 C.

4. The method for preparing aluminosilicate particles of claim 1, wherein the aluminosilicate particles are amorphous compounds having a composition of the following Chemical Formula 1:
M.sub.x/n[(AlO.sub.2).sub.x,(SiO.sub.2).sub.y].m(H.sub.2O) [Chemical Formula 1] wherein, in Chemical Formula 1, M is an element selected from the group consisting of Li, Na, K, Rb, Cs, Be, and Fr, or an ion thereof; x>0, y>0, n>0, and m>0; 1.0y/x5.0; and 0.5x/n1.2.

5. A reinforcing material for rubber comprising amorphous aluminosilicate particles having a composition of the following Chemical Formula 1, wherein the aluminosilicate particles satisfy the following conditions: in a data plot obtained by X-ray diffraction (XRD), a full width at half maximum (FWHM) in a 2 range of 20 to 37 is 3 to 8.5, a maximum peak intensity (I.sub.max) is in a 2 range of 26 to 31, and the aluminosilicate particles exhibit a pattern having no peak of crystalline SiO.sub.2 (JCPDS standard pattern number #46-1045), an average particle diameter is 10 to 100 nm, a Brunauer-Emmett-Teller surface area (S.sub.BET) is 80 to 250 m.sup.2/g, and an external specific surface area (S.sub.EXT) is 60 to 200 m.sup.2/g according to an analysis of nitrogen adsorption/desorption:
M.sub.x/n[(AlO.sub.2).sub.x,(SiO.sub.2).sub.y].m(H.sub.2O) [Chemical Formula 1] wherein, in Chemical Formula 1, M is an element selected from the group consisting of Li, Na, K, Rb, Cs, Be, and Fr, or an ion thereof; x>0, y>0, n>0, and m>0; 1.0y/x5.0; and 0.5x/n1.2.

6. The reinforcing material for rubber of claim 5, wherein the aluminosilicate particles satisfy 0.8S.sub.EXT/S.sub.BET1.0.

7. The reinforcing material for rubber of claim 5, wherein the aluminosilicate particles have a volume (V.sub.micro) of micropores having a pore size of less than 2 nm calculated from the S.sub.BET by a t-plot method of less than 0.05 cm.sup.3/g.

8. The reinforcing material for rubber of claim 5, wherein the aluminosilicate particles have a particle size distribution which shows a volume average particle diameter (D.sub.mean) of 1 to 25 m, a geometric standard deviation of 1 to 20 m, and a 90% cumulative particle diameter (D.sub.90) of 1 to 100 m, when measured under distilled water.

9. A rubber composition for tires comprising the reinforcing material for rubber of claim 5 and at least one diene elastomer.

10. The rubber composition for tires of claim 9, wherein the diene elastomer is at least one compound selected from the group consisting of a natural rubber, polybutadiene, polyisoprene, a butadiene/styrene copolymer, a butadiene/isoprene copolymer, a butadiene/acrylonitrile copolymer, an isoprene/styrene copolymer, and a butadiene/styrene/isoprene copolymer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows scanning electron microscopy (SEM) images of the aluminosilicate particles according to Example 1 [(a) 5000 times magnification; (b) 100,000 times magnification].

(2) FIG. 2 shows SEM images of the aluminosilicate particles according to Comparative Example 1 [(a) 5,000 times magnification; (b) 100,000 times magnification].

(3) FIG. 3 shows graphs of particle size distribution for the aluminosilicate particles of Example 1 and Comparative Example 1 [(a) Example 1; (b) Comparative Example 1].

(4) FIG. 4 shows X-ray diffraction analysis patterns for the aluminosilicate particles according to Examples 1 and 2 [(a) Example 1; (b) Example 2].

(5) FIG. 5 shows X-ray diffraction analysis patterns for the aluminosilicate particles according to Comparative Examples 1 and 2 [(a) Comparative Example 1; (b) Comparative Example 2].

(6) FIG. 6 shows transmission electron microscopy (TEM) images of the rubber molded product according to Preparation Example 1 [(a) scale bar 1 m; (b) scale bar 500 nm].

(7) FIG. 7 shows TEM images of the rubber molded product according to Comparative Preparation Example 1 [(a) scale bar 1 m; (b) scale bar 500 nm].

DETAILED DESCRIPTION OF THE EMBODIMENTS

(8) Hereinafter, preferred examples are provided for better understanding. However, these examples are for illustrative purposes only, and the invention is not intended to be limited by these examples.

Example 1

(9) 23 g of KOH (Daejung Chemicals & Metals) and 27 g of colloidal silica (Ludox HS 30 wt %, Sigma-Aldrich) were completely dissolved in 62 ml of distilled water (DW). 15 g of metakaolin (Al.sub.2Si.sub.2O.sub.7, Sigma-Aldrich) was added to the solution, followed by mixing at 800 rpm for 40 minutes using an overhead stirrer.

(10) This was cured at a temperature of about 70 C. for 4 hours.

(11) The solid product obtained by curing was poured into distilled water, stirred for 12 hours, and centrifuged to wash it to about pH 7.

(12) The washed solid product was dispersed in distilled water to form a colloidal solution, followed by centrifugation at 1500 rpm for 5 minutes to precipitate the unreacted sources. From this, a supernatant liquid in which the aluminosilicate particles were dispersed was obtained and the precipitated unreacted sources were discarded.

(13) It was confirmed by analysis that the precipitated unreacted sources contain SiO.sub.2 flakes which are a kind of unreacted sources which were present in the solid product.

(14) The supernatant liquid in which the aluminosilicate particles were dispersed was dried in an oven at 70 C. for 24 hours to obtain final aluminosilicate particles.

Example 2

(15) Aluminosilicate particles were obtained in the same manner as in Example 1, except that metakaolin (Al.sub.2Si.sub.2O.sub.7, BASF, SP33) was used instead of the metakaolin (Al.sub.2Si.sub.2O.sub.7, Sigma-Aldrich).

(16) Specifically, 23 g of KOH (Daejung Chemicals & Metals) and 27 g of colloidal silica (Ludox HS 30 wt %, Sigma-Aldrich) were completely dissolved in 62 ml of distilled water (DW). 15 g of metakaolin (Al.sub.2Si.sub.2O.sub.7, BASF, SP33) was added to the solution, followed by mixing at 800 rpm for 40 minutes using an overhead stirrer.

(17) This was cured at room temperature of about 70 C. for 4 hours.

(18) The solid product obtained by curing was poured into distilled water, stirred for 12 hours, and centrifuged to wash it to about pH 7.

(19) The washed solid product was dispersed in distilled water to form a colloidal solution, followed by centrifugation at 1500 rpm for 5 minutes to precipitate the unreacted sources. From this, a supernatant liquid in which the aluminosilicate particles were dispersed was obtained and the precipitated unreacted sources were discarded.

(20) It was confirmed by analysis that the precipitated unreacted sources contain SiO.sub.2 flakes which are a kind of unreacted sources which were present in the solid product.

(21) The supernatant liquid in which the aluminosilicate particles were dispersed was dried in an oven at 70 C. for 24 hours to obtain final aluminosilicate particles.

Comparative Example 1

(22) Aluminosilicate particles were obtained in the same manner as in Example 1, except that the step of purification for the washed solid product was not performed.

(23) Specifically, 23 g of KOH (Daejung Chemicals & Metals) and 27 g of colloidal silica (Ludox HS 30 wt %, Sigma-Aldrich) were completely dissolved in 62 ml of distilled water (DW). 15 g of metakaolin (Al.sub.2Si.sub.2O.sub.7, Sigma-Aldrich) was added to the solution, followed by mixing at 800 rpm for 40 minutes using an overhead stirrer.

(24) This was cured at room temperature of about 70 C. for 4 hours.

(25) The solid product obtained by curing was poured into distilled water, stirred for 12 hours, and centrifuged to wash it to about pH 7.

(26) The washed solid product was dried in an oven at 70 C. for 24 hours to obtain final aluminosilicate particles.

Comparative Example 2

(27) Aluminosilicate particles were obtained in the same manner as in Example 2, except that the step of purification for the washed solid product was not performed.

(28) Specifically, 23 g of KOH (Daejung Chemicals & Metals) and 27 g of colloidal silica (Ludox HS 30 wt %, Sigma-Aldrich) were completely dissolved in 62 ml of distilled water (DW). 15 g of metakaolin (Al.sub.2Si.sub.2O.sub.7, BASF, SP33) was added to the solution, followed by mixing at 800 rpm for 40 minutes using an overhead stirrer. This was cured at room temperature of about 70 C. for 4 hours.

(29) The solid product obtained by curing was poured into distilled water, stirred for 12 hours, and centrifuged to wash it to about pH 7.

(30) The washed solid product was dried in an oven at 70 C. for 24 hours to obtain final aluminosilicate particles.

Preparation Example 1

(31) 728.01 g of a diene elastomer mixture (SSBR 2550, LG Chem), 370.62 g of aluminosilicate particles according to Example 1 as a reinforcing material, 59.30 g of a silane coupling agent (X50-S, Evonik Industries), and 52.94 g of additives (antioxidant, dispersion accelerator, vulcanization assistant, etc.) were added to a Banbury mixer, and a CMB (carbon master batch) was produced at 150 C. The resulting mixture was extruded in the form of a sheet having a thickness of 2 to 3 mm.

(32) The CMB sheet was aged at room temperature for 24 hours, and then added into a Banbury mixer together with 24.75 g of a vulcanizing agent and a vulcanization accelerator to produce an FMB (final master batch). The resulting mixture was extruded in the form of a sheet having a thickness of 2 to 3 mm.

(33) This was crosslinked at 160 C. to obtain a rubber molded product. At this time, the crosslinking time was controlled with reference to data obtained by measuring the above mixture at 160 C. using a moving die rheometer (MDR).

Preparation Example 2

(34) 728.01 g of a diene elastomer mixture (SSBR 2550, LG Chem), 370.62 g of aluminosilicate particles according to Example 2 as a reinforcing material, 59.30 g of a silane coupling agent (X50-S, Evonik Industries), and 52.94 g of additives (antioxidant, dispersion accelerator, vulcanization assistant, etc.) were added to a Banbury mixer and a CMB (carbon master batch) was produced at 150 C. The resulting mixture was extruded in the form of a sheet having a thickness of 2 to 3 mm.

(35) The CMB sheet was aged at room temperature for 24 hours, and then added into a Banbury mixer together with 24.75 g of a vulcanizing agent and a vulcanization accelerator to produce an FMB (final master batch). The resulting mixture was extruded in the form of a sheet having a thickness of 2 to 3 mm.

(36) This was crosslinked at 160 C. to obtain a rubber molded product. At this time, the crosslinking time was controlled with reference to data obtained by measuring the above mixture at 160 C. using a moving die rheometer (MDR).

Comparative Preparation Example 1

(37) 730.96 g of a diene elastomer mixture (SSBR 2550, LG Chem), 372.12 g of aluminosilicate particles according to Comparative Example 1 as a reinforcing material, 59.54 g of a silane coupling agent (X50-S, Evonik Industries) and 53.16 g of additives (antioxidant, dispersion accelerator, vulcanization assistant, etc.) were added to a Banbury mixer and a CMB (carbon master batch) was produced at 150 C. The resulting mixture was extruded in the form of a sheet having a thickness of 2 to 3 mm.

(38) The CMB sheet was aged at room temperature for 24 hours, and then added into a Banbury mixer together with 24.84 g of a vulcanizing agent and a vulcanization accelerator to produce an FMB (final master batch). The resulting mixture was extruded in the form of a sheet having a thickness of 2 to 3 mm.

Comparative Preparation Example 2

(39) 730.96 g of a diene elastomer mixture (SSBR 2550, LG Chem), 372.12 g of aluminosilicate particles according to Comparative Example 2 as a reinforcing material, 59.54 g of a silane coupling agent (X50-S, Evonik Industries) and 53.16 g of additives (antioxidant, dispersion accelerator, vulcanization assistant, etc.) were added to a Banbury mixer and a CMB (carbon master batch) was produced at 150 C. The resulting mixture was extruded in the form of a sheet having a thickness of 2 to 3 mm.

(40) The CMB sheet was aged at room temperature for 24 hours, and then added into a Banbury mixer together with 24.84 g of a vulcanizing agent and a vulcanization accelerator to produce an FMB (final master batch). The resulting mixture was extruded in the form of a sheet having a thickness of 2 to 3 mm.

Experimental Example 1

(41) Scanning electron microscopy (SEM) images of the aluminosilicate particles according to the examples and comparative examples were taken.

(42) FIG. 1 shows images of the particles according to Example 1 [(a) 5000 times magnification; (b) 100,000 times magnification], and FIG. 2 shows images of the particles according to Comparative Example 1 [(a) 5000 times magnification; (b) 100,000 times magnification].

(43) Referring to FIG. 1, it was confirmed that the particles of Example 1 were composed of primary particles of 30 to 40 nm and did not form aggregates.

(44) Referring to FIG. 2, it was confirmed that the particles of Comparative Example 1 formed aggregates in a micrometer scale. Further, it was confirmed that some of the primary particles on the surface of the aggregates have a size of 30 to 40 nm which is similar to that of Example 1, but the inside of the aggregates was composed of a plate-like structure in a hundred nanometer scale.

Experimental Example 2

(45) The nitrogen adsorption/desorption Brunauer-Emmett-Teller surface area (S.sub.BET) and the external specific surface area (S.sub.EXT) were measured for each of the particles according to the examples and comparative examples using a specific surface area analyzer (BEL Japan Inc., BELSORP_MAX). Then, the volume of micropores (V.sub.micro) having a pore size of less than 2 nm was calculated from the S.sub.BET by a t-plot method.

(46) TABLE-US-00001 TABLE 1 Primary particle size S.sub.BET S.sub.EXT V.sub.micro (nm) (m.sup.2/g) (m.sup.2/g) S.sub.EXT/S.sub.BET (cm.sup.3/g) Example 1 30 104.37 89.33 0.88 0.006 Example 2 30 94.89 84.25 0.89 0.005 Comp. Ex. 1 30 101.19 87.96 0.84 0.005 Comp. Ex. 2 30 84.45 75.55 0.89 0.004

Experimental Example 3

(47) 0.1 g of the particles according to the examples and comparative examples were added to 10 ml of distilled water. Then, it was sonicated for 5 minutes at 90% power in a 100 W pulsed ultrasonication apparatus. Here, the energy by the sonication acts as physical energy similar to mechanical force applied to the composition when the rubber composition is blended, so that the size distribution of the aggregates dispersed in the rubber composition can be indirectly compared.

(48) The resulting dispersion was sonicated for another 2 minutes, and then a size distribution, a volume average particle diameter (D.sub.mean), a geometric standard deviation (Std. Dev.), and a cumulative particle diameter of the volume distribution (D.sub.10, D.sub.50, D.sub.90) of the aggregates were measured using a particle size analyzer (manufactured by HORIBA, model name LA960, laser diffraction type).

(49) The particles are dispersed in a nanoscale size with little aggregation when dispersed in the rubber composition. However, when the particles are measured using the particle size analyzer, they tend to aggregate more due to the use of water as a solvent. For this reason, the following measurement results are in a microscale size. That is, the particle size analyzer measurement can be understood to be performed not to directly determine the size distribution of the particles dispersed in the rubber composition but to relatively compare the size distribution of the particles.

(50) FIG. 3 shows graphs of a particle size distribution for the aluminosilicate particles of Example 1 and Comparative Example 1 [(a) Example 1; (b) Comparative Example 1].

(51) TABLE-US-00002 TABLE 2 Example 1 Comparative Example 1 D.sub.mean (m) 21.7178 104.5625 Std. Dev. (m) 15.7814 144.6984 D.sub.10 (m) 10.5253 9.6960 D.sub.50 (m) 13.2095 61.7261 D.sub.90 (m) 48.3251 431.1577

(52) Referring to Table 2 and FIG. 3, the particles of Example 1 hardly formed aggregates, and had a uniform particle size distribution. On the other hand, the particles of Comparative Example 1 mostly formed aggregates, which showed a significant difference in D.sub.mean, Std. Dev., D.sub.50, and D.sub.90 as compared with the particles of Example 1.

Experimental Example 4

(53) X-ray diffraction analysis for each aluminosilicate particle according to the examples and comparative examples was carried out using an X-ray diffractometer (Bruker AXS D4-Endeavor XRD) under an applied voltage of 40 kV and an applied current of 40 mA.

(54) FIG. 4 shows X-ray diffraction analysis patterns for the aluminosilicate particles according to Examples 1 and 2 [(a) Example 1; (b) Example 2].

(55) FIG. 5 shows X-ray diffraction analysis patterns for the aluminosilicate particles according to Comparative Examples 1 and 2 [(a) Comparative Example 1; (b) Comparative Example 2].

(56) The measured range of 28 was 10 to 90, and it was scanned at an interval of 0.05. Herein, a variable divergence slit of 6 mm was used as a slit, and a large PMMA holder (diameter=20 mm) was used to eliminate background noise due to the PMMA holder.

(57) Further, a full width at half maximum (FWHM) at a peak of about 29 which is the maximum peak in the 2 range of 20 to 37 was calculated in the data plot obtained by X-ray diffraction (XRD).

(58) As a result, it was confirmed that the aluminosilicate particles of Examples 1 to 2 and Comparative Examples 1 and 2 have an amorphous structure (FWHM=6.745, 28@I.sub.max=29.2 in the 2 range of 20 to 37 of XRD).

(59) However, referring to FIGS. 4 and 5, the aluminosilicate particles of Examples 1 and 2 exhibited a pattern having no peak of crystalline SiO.sub.2 (JCPDS standard pattern number #46-1045), whereas Comparative Examples 1 and 2 exhibited a pattern having the peak of crystalline SiO.sub.2.

(60) That is, both of the aluminosilicate particles of the examples and comparative examples are amorphous, but the particles of Comparative Examples 1 and 2 were confirmed to exhibit the above-mentioned pattern due to the presence of crystalline SiO.sub.2 as an unreacted source inside thereof, while the particles of Examples 1 and 2 were confirmed to have no crystalline SiO.sub.2.

Experimental Example 5

(61) Component analysis for the aluminosilicate particles of Example 1 and Comparative Example 1 was carried out by X-ray fluorescence (XRF) analysis (HORIBA).

(62) TABLE-US-00003 TABLE 3 (mass %) Example 1 Comparative Example 1 SiO.sub.2 48.12 46.60 Al.sub.2O.sub.3 25.65 25.82 K.sub.2O 25.08 23.45 TiO.sub.2 0.13 2.30 Fe.sub.2O.sub.3 0.48 0.71 CaO 0.18 0.37 Na.sub.2O 0.21 0.29 MgO 0.03 0.12 etc. 0.12 0.34

(63) Each aluminosilicate particles of Example 1 and Comparative Example 1 contained Si, K, Al, and O as major components.

(64) It was confirmed that the particles of Example 1 had an impurity content of 1.15 mass % excluding SiO.sub.2, Al.sub.2O.sub.3, and K.sub.2O. On the other hand, the particles of Comparative Example 1 had an impurity content of 4.13 mass %, which is 4 times that of Example 1.

Experimental Example 6

(65) The dispersion state of the rubber molded products according to preparation examples and comparative preparation examples was observed using a transmission electron microscope (TEM). The photographed TEM images are shown in FIG. 6 [Preparation Example 1(a) scale bar 1 m; (b) scale bar 500 nm] and FIG. 7 [Comparative Preparation Example 1(a) scale bar 1 m; (b) scale bar 500 nm].

(66) Referring to FIGS. 6 and 7, it can be confirmed that Preparation Example 1 to which the aluminosilicate particles of Example 1 were applied exhibited a remarkably superior dispersion state of the reinforcing material than Comparative Preparation Example 1.

Experimental Example 7

(67) (1) The dynamic loss factor (tan ) of the rubber molded products of Preparation Examples 1 to 2 and Comparative Preparation Examples 1 to 2 was measured under a dynamic strain of 3% and a static strain of 3% using a viscoelasticity measurement apparatus (DMTS 500N, Gabo, Germany).

(68) For reference, the dynamic loss factor (tan @0 C.) at 0 C. is related to wet grip property of tires. Further, it is known that the higher the value, the better the wet grip property. In addition, the dynamic loss factor (tan @60 C.) at 60 C. is related to rolling resistance of tires. It is also known that the lower the value, the better the rolling resistance.

(69) (2) Abrasion resistance index (A.R.I.) of the rubber molded products according to Preparation Examples 1 to 2 and Comparative Preparation Examples 1 to 2 was measured by an abrasion tester (Bareiss GmbH) in accordance with DIN ISO 4649.

(70) The abrasion resistance index was calculated as {[(loss weight of the material) X (specific gravity of the material)]/[(loss weight of the reference material)(specific gravity of the reference material)]}100 (reference material: neutral rubber).

(71) TABLE-US-00004 TABLE 4 Comp. Comp. Prep. Ex. 1 Prep. Ex. 2 Prep. Ex. 1 Prep. Ex. 2 tan @0 C. 0.9251 0.9442 0.9202 0.9382 tan @60 C. 0.1120 0.1063 0.1001 0.0967 A.R.I. 123.2 119.6 104.6 102.6

(72) Referring to Table 4, it was confirmed that the rubber molded product according to Preparation Example 1 exhibited wet grip and rolling resistance characteristics similar to those of Comparative Preparation Example 1, and also had remarkably improved abrasion resistance.