REINFORCING MATERIAL FOR RUBBER COMPRISING ALUMINOSILICATE PARTICLES AND RUBBER COMPOSITION FOR TIRES COMPRISING THE SAME

Abstract

The present disclosure relates to a reinforcing material for rubber including aluminosilicate particles and a rubber composition for tires including the same. The reinforcing material for rubber according to the present disclosure exhibits excellent dispersibility in the rubber composition and reinforcing effect, and thus can be suitably used for eco-friendly tires requiring high efficiency and high fuel efficiency characteristics.

Claims

1. 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, and a maximum peak intensity (I.sub.max) is in a 2 range of 26 to 31, an average primary 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, and a volume of micropores (V.sub.micro) having a pore size of less than 2 nm calculated from the S.sub.BET by a t-plot method is less than 0.05 cm.sup.3/g:
M.sub.x/n[(AlO.sub.2).sub.x,(SiO.sub.2).sub.y].Math.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 m0; 1.0y/x5.0; and 0.5x/n1.2.

2. The reinforcing material for rubber of claim 1, wherein the aluminosilicate particles satisfy 0.8S.sub.EXT/S.sub.BET1.0.

3. A rubber composition for tires comprising the reinforcing material for rubber of claim 1.

4. The rubber composition for tires of claim 3, wherein the composition comprises the reinforcing material for rubber and at least one diene elastomer.

5. The rubber composition for tires of claim 4, 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

[0084] FIG. 1 is a graph showing the results of X-ray diffraction analysis of the aluminosilicate particles according to Example 1.

[0085] FIG. 2 is a graph showing the results of X-ray diffraction analysis of the aluminosilicate particles according to Example 3.

[0086] FIG. 3 is a graph showing the results of X-ray diffraction analysis of the aluminosilicate particles according to Example 5.

[0087] FIG. 4 is a graph showing the results of X-ray diffraction analysis of the aluminosilicate particles according to Example 8.

[0088] FIG. 5 is a graph showing the results of X-ray diffraction analysis of the aluminosilicate particles according to Example 9.

[0089] FIG. 6 is a SEM image of the aluminosilicate particles according to Example 1.

[0090] FIG. 7 is a SEM image of the aluminosilicate particles according to Example 2.

[0091] FIG. 8 is a SEM image of the aluminosilicate particles according to Example 3.

[0092] FIG. 9 is a SEM image of the aluminosilicate particles according to Example 4.

[0093] FIG. 10 is a SEM image of the aluminosilicate particles according to Example 5.

[0094] FIG. 11 is a SEM image of the aluminosilicate particles according to Example 6.

[0095] FIG. 12 is a SEM image of the aluminosilicate particles according to Example 7.

[0096] FIG. 13 is a SEM image of the aluminosilicate particles according to Example 8.

[0097] FIG. 14 (a) is an image of the rubber molded product applied with the aluminosilicate particles of Example 2 observed by a transmission electron microscope, and FIG. 14 (b) is an image of the rubber molded product applied with the silica of Example 9 observed by a transmission electron microscope.

[0098] FIG. 15 is an image of the rubber composition of Preparation Example 5 observed by a transmission electron microscope.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0099] Hereinafter, preferred examples are provided for better understanding.

[0100] However, these examples are for illustrative purposes only, and the invention is not intended to be limited by these examples.

Example 1

[0101] 23 g of KOH (Daejung Chemicals & Metals) and 27 g of colloidal silica (Ludox HS 30 wt %, Sigma-Aldrich) were completely dissolved in 22 ml of distilled water (DW). 15 g of metakaolin (Al.sub.2Si.sub.2O.sub.7, Aldrich) was added to the solution, followed by mixing at 800 rpm for 40 minutes using an overhead stirrer.

[0102] This was cured at room temperature of about 25 C. for 24 hours.

[0103] The cured product was poured into distilled water at 90 C., stirred for 12 hours, and centrifuged to wash it to about pH 7.

[0104] It was confirmed that the washed and dried aluminosilicate had an amorphous structure (FWHM=6.745, 2@I.sub.max=29.2 in the 2 range of 20 to 37 of XRD), and a composition of y/x=1.6, x/n=1.12 in Chemical Formula 1.

[0105] The aluminosilicate formed in the form of about 20 nm primary particles without forming secondary particles was subjected to specific surface area analysis, and the results were S.sub.BET=130 m.sup.2/g, S.sub.EXT=110 m.sup.2/g, S.sub.EXT/S.sub.BET=0.85, and V.sub.micro=0.007 cm.sup.3/g.

Example 2

[0106] 23 g of KOH (Daejung Chemicals & Metals) and 27 g of colloidal silica (Ludox HS 30 wt %; Sigma-Aldrich) were completely dissolved in 22 ml of distilled water (DW). 15 g of metakaolin (Al.sub.2Si.sub.2O.sub.7, Aldrich) was added to the solution, followed by mixing at 800 rpm for 40 minutes using an overhead stirrer.

[0107] This was cured at 70 C. for 4 hours.

[0108] The cured product was poured into distilled water at 90 C., stirred for 12 hours, and centrifuged to wash it to about pH 7.

[0109] It was confirmed that the washed and dried aluminosilicate had an amorphous structure (FWHM=6.496, 2@I.sub.max=29.2 in the 2 range of 20 to 37 of XRD), and a composition of y/x=1.6, x/n=0.8 in Chemical Formula 1.

[0110] The aluminosilicate formed in the form of about 20 nm primary particles without forming secondary particles was subjected to specific surface area analysis, and the results were S.sub.BET=130 m.sup.2/g, S.sub.EXT=110 m.sup.2/g, S.sub.EXT/S.sub.BET=0.85, and V.sub.micro=0.007 cm.sup.3/g.

Example 3

[0111] 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, Aldrich) was added to the solution, followed by mixing at 800 rpm for 40 minutes using an overhead stirrer.

[0112] This was cured at 70 C. for 4 hours.

[0113] The cured product was poured into distilled water at 90 C., stirred for 12 hours, and centrifuged to wash it to about pH 7.

[0114] It was confirmed that the washed and dried aluminosilicate had an amorphous structure (FWHM=6.206, 2@I.sub.max=29.10 in the 2 range of 20 to 37 of XRD), and a composition of y/x=1.91, x/n=0.88 in Chemical Formula 1.

[0115] The aluminosilicate formed in the form of about 30 nm primary particles without forming secondary particles was subjected to specific surface area analysis, and the results were S.sub.BET=100 m.sup.2/g, S.sub.EXT=90 m.sup.2/g, S.sub.EXT/S.sub.BET=0.9, and V.sub.micro=0.005 cm.sup.3/g.

Example 4

[0116] 23 g of KOH (Daejung Chemicals & Metals) and 33 g of a Na.sub.2SiO.sub.5 solution (Aldrich) were completely dissolved in 21 ml of distilled water (DW). 15 g of metakaolin (Al.sub.2Si.sub.2O.sub.7, Aldrich) was added to the solution, followed by mixing at 800 rpm for 40 minutes using an overhead stirrer.

[0117] This was cured at 70 C. for 4 hours.

[0118] The cured product was poured into distilled water at 90 C., stirred for 12 hours, and centrifuged to wash it to about pH 7.

[0119] It was confirmed that the washed and dried aluminosilicate had an amorphous structure (FWHM=6.752, 2@I.sub.max=29.2 in the 2 range of 20 to 37 of XRD), and a composition of y/x=1.91, x/n=0.88 in Chemical Formula 1.

[0120] The aluminosilicate formed in the form of about 30 nm primary particles without forming secondary particles was subjected to specific surface area analysis, and the results were S.sub.BET=110 m.sup.2/g, S.sub.EXT=100 m.sup.2/g, S.sub.EXT/S.sub.BET=0.91, and V.sub.micro=0.005 cm.sup.3/g.

Example 5

[0121] 12 g of NaOH (Daejung Chemicals & Metals) and 31 g of a Na.sub.2SiO.sub.5 solution (Aldrich) were completely dissolved in 22 ml of distilled water (DW). 15 g of metakaolin (Al.sub.2Si.sub.2O.sub.7, Aldrich) was added to the solution, followed by mixing at 800 rpm for 40 minutes using an overhead stirrer.

[0122] This was cured at room temperature of about 25 C. for 24 hours.

[0123] The cured product was poured into distilled water at 90 C., stirred for 12 hours, and centrifuged to wash it to about pH 7.

[0124] The washed and dried aluminosilicate had a FAU (faujasite) crystal structure, so the FWHM measurement in the range was not performed. It was confirmed that the aluminosilicate had a composition of y/x=1.31 and x/n=0.91 in Chemical Formula 1.

[0125] The aluminosilicate in the form of mostly secondary particles with a particle size of about 150 nm was subjected to specific surface area analysis, and the results were S.sub.BET=520 m.sup.2/g, S.sub.EXT=190 m.sup.2/g, S.sub.EXT/S.sub.BET=0.37, and V.sub.micro=0.13 cm.sup.3/g.

Example 6

[0126] 12 g of NaOH (Daejung Chemicals & Metals) and 31 g of a Na.sub.2SiO.sub.5 solution (Aldrich) were completely dissolved in 22 ml of distilled water (DW). 22 g of metakaolin (Al.sub.2Si.sub.2O.sub.7, Aldrich) was added to the solution, followed by mixing at 800 rpm for 40 minutes using an overhead stirrer.

[0127] This was cured at room temperature of about 25 C. for 24 hours.

[0128] The cured product was poured into distilled water at 25 C., stirred for 12 hours, and centrifuged to wash it to about pH 7.

[0129] It was confirmed that the washed and dried aluminosilicate had an amorphous structure (FWHM=3.872, 20@I.sub.max=29.0 in the 20 range of 20 to 37 of XRD), and a composition of y/x=1.56, x/n=0.95 in Chemical Formula 1.

[0130] The aluminosilicate formed in the form of about 30 nm primary particles without forming secondary particles was subjected to specific surface area analysis, and the results were S.sub.BET=610 m.sup.2/g, S.sub.EXT=173 m.sup.2/g, S.sub.EXT/S.sub.BET=0.28, and V.sub.micro=0.78 cm.sup.3/g.

Example 7

[0131] 12 g of NaOH (Daejung Chemicals & Metals) and 31 g of a Na.sub.2SiO.sub.5 solution (Aldrich) were completely dissolved in 22 ml of distilled water (DW). 15 g of metakaolin (Al.sub.2Si.sub.2O.sub.7, Aldrich) was added to the solution, followed by mixing at 800 rpm for 40 minutes using an overhead stirrer.

[0132] This was cured at 70 C. for 6 hours.

[0133] The cured product was poured into distilled water at 90 C., stirred for 12 hours, and centrifuged to wash it to about pH 7.

[0134] The washed and dried aluminosilicate had a FAU (faujasite) crystal structure, so the FWHM measurement in the range was not performed. It was confirmed that the aluminosilicate had a composition of y/x=1.48 and x/n=0.94 in Chemical Formula 1.

[0135] The aluminosilicate in the form of about 200 nm secondary particles formed by agglomeration of about 40 nm primary particles was subjected to specific surface area analysis, and the results were S.sub.BET=660 m.sup.2/g, S.sub.EXT=200 m.sup.2/g, S.sub.EXT/S.sub.BET=0.30, and V.sub.micro=0.19 cm.sup.3/g.

Example 8

[0136] An aluminosilicate (product name: Zeolex 23A) manufactured by Huber Engineered Materials was prepared.

[0137] The aluminosilicate had an amorphous structure in general, but some crystalline structures were mixed and exhibited an XRD pattern (FWHM=8.538, 26@I.sub.max=23.7 in the 2 range of 20 to 37 of XRD) different from the particles according to Examples 1 to 4. Further, it was confirmed that the aluminosilicate had a composition of M=Na, y/x=8.63 and x/n=1.05 in Chemical Formula 1.

[0138] The aluminosilicate of about 20 nm was subjected to specific surface area analysis, and the results were S.sub.BET=82.49 m.sup.2/g, S.sub.EXT=74.59 m.sup.2/g, S.sub.EXT/S.sub.BET=0.90, and V.sub.micro=0.003 cm.sup.3/g.

Example 9

[0139] Silica (product name: 7000GR) manufactured by Evonic was prepared.

[0140] The silica had 26@I.sub.max of 22.2. It was subjected to specific surface area analysis, and the results were S.sub.BET=175 m.sup.2/g, S.sub.EXT=144 m.sup.2/g, S.sub.EXT/S.sub.BET=0.82, and V.sub.micro=0.012 cm.sup.3/g.

Preparation Example 1

[0141] 137 g of a diene elastomer mixture (SSBR 2550, LG Chemical), 70 g of the aluminosilicate particles according to Example 1 as a reinforcing material, and 11.2 g of a silane coupling agent (polysiloxane-based) were added to a closed mixer. This was mixed at 150 C. for 5 minutes, and then mixed with sulfur and a vulcanization accelerator for 90 seconds.

[0142] The resulting mixture was extruded in the form of a sheet having a thickness of 2 to 3 mm, and vulcanized at 160 C. to obtain a rubber molded product. At this time, the vulcanization time was controlled referring to data obtained by measuring the above mixture at 160 C. using a moving die rheometer (MDR).

[0143] A bound rubber value of the rubber composition according to Preparation Example 1 was measured as 115. The bound rubber value is a normalized value when the bound rubber value of the rubber including silica is taken as 100.

Preparation Example 2

[0144] A rubber composition and a molded product were obtained in the same manner as in Preparation Example 1, except that the aluminosilicate particles according to Example 2 were added as a reinforcing material.

[0145] The bound rubber value of the rubber composition according to Preparation Example 2 was measured as 115.

Preparation Example 3

[0146] A rubber composition and a molded product were obtained in the same manner as in Preparation Example 1, except that the aluminosilicate particles according to Example 3 were added as a reinforcing material.

[0147] The bound rubber value of the rubber composition according to Preparation Example 3 was measured as 93.

Preparation Example 4

[0148] A rubber composition and a molded product were obtained in the same manner as in Preparation Example 1, except that the aluminosilicate particles according to Example 4 were added as a reinforcing material.

[0149] The bound rubber value of the rubber composition according to Preparation Example 4 was measured as 127.

Preparation Example 5

[0150] A rubber composition and a molded product were obtained in the same manner as in Preparation Example 1, except that the aluminosilicate particles according to Example 5 were added as a reinforcing material.

[0151] However, the rubber composition according to Preparation Example 5 was unable to be evaluated regarding rubber compounding characteristics of the composition due to the increase in agglomeration of the aluminosilicate particles and the decrease in dispersibility during compounding (see agglomerates indicated by an arrow of FIG. 15).

Preparation Example 6

[0152] A rubber composition and a molded product were obtained in the same manner as in Preparation Example 1, except that the aluminosilicate particles according to Example 6 were added as a reinforcing material.

[0153] However, the rubber composition according to Preparation Example 6 was unable to be evaluated regarding rubber compounding characteristics of the composition due to the increase in agglomeration of the aluminosilicate particles and the decrease in dispersibility during compounding.

Preparation Example 7

[0154] A rubber composition and a molded product were obtained in the same manner as in Preparation Example 1, except that the aluminosilicate particles according to Example 7 were added as a reinforcing material.

[0155] However, the rubber composition according to Preparation Example 7 was unable to be evaluated regarding rubber compounding characteristics of the composition due to the increase in agglomeration of the aluminosilicate particles and the decrease in dispersibility during compounding.

Preparation Example 8

[0156] A rubber composition was obtained in the same manner as in Preparation Example 1, except that the aluminosilicate particles according to Example 8 were added as a reinforcing material.

[0157] However, the rubber composition according to Preparation Example 8 was unable to produce a molded product, because the rubber was decomposed at the time of compounding.

Preparation Example 9

[0158] A rubber composition and a molded product were obtained in the same manner as in Preparation Example 1, except that the silica particles according to Example 9 were added as a reinforcing material.

Experimental Example 1

[0159] (1) The average primary particle diameter and composition of the aluminosilicate particles according to Examples 1 to 8 were confirmed using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The photographed SEM images are sequentially shown in FIG. 6 (Example 1) to FIG. 13 (Example 8).

[0160] In the measurement of the average primary particle diameter, the particle diameter means a Feret diameter and was calculated as an average of the values obtained by measuring the particle diameters in various directions. Specifically, after obtaining a SEM image in which more than 100 particles were observed, a random straight line was plotted, and the primary particle diameter of the particle was calculated using the length of the straight line, the number of particles included in the straight line, and the magnification. The average primary particle diameter was determined by setting 20 or more of these straight lines.

[0161] The EDS was operated under conditions of 15 kV and a working distance of 15 mm.

[0162] (2) 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 Examples 1 to 8 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.

[0163] The specific surface area analysis can be performed by measuring the amount of gas adsorption while increasing the gas partial pressure to a saturated vapor pressure (P.sub.0) and measuring the amount of gas desorption while reducing the partial pressure after the saturated vapor pressure state (P/P.sub.0=1) to obtain an isotherm ads/des graph. Using this, S.sub.BET can be obtained by a BET plot, and S.sub.EXT and V.sub.micro can be calculated by a t-plot.

TABLE-US-00001 TABLE 1 Diameter 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 20 130 110 0.85 0.007 Example 2 20 130 110 0.85 0.007 Example 3 30 100 90 0.90 0.005 Example 4 30 110 100 0.91 0.005 Example 5 150 520 190 0.37 0.13 Example 6 30 610 173 0.28 0.78 Example 7 40/200 660 200 0.30 0.19 Example 8 20 82.49 74.59 0.90 0.003

Experimental Example 2

[0164] X-ray diffraction analysis for each aluminosilicate particle according to Examples 1 to 8 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. The results are shown in Table 2 below.

[0165] The measured range of 26 was 10 to 90, and it was scanned at an interval of 0.05. Herein, a variable divergence slit 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.

[0166] The data plots obtained by X-ray diffraction are shown in FIG. 1 (Example 1), FIG. 2 (Example 3), FIG. 3 (Example 5), FIG. 4 (Example 8), and FIG. 5 (Example 9).

[0167] And, 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).

Experimental Example 3

[0168] A Time-Domain NMR (Minispec) was used to obtain signal decay over time by setting the application mode to sc-lc-co at a temperature of 40 C. The bound rubber value can be calculated through double exponential fitting from the measured graph. The bound rubber value of the rubber composition prepared according to the above preparation examples was a normalized value when the calculated silica bound rubber value of the silica-kneaded rubber composition was taken as 100.

[0169] The bound rubber is a component formed on the surface of the filler in the unvulcanized rubber composition in which the filler is kneaded, and it is possible to indirectly confirm the reinforcing effect due to the addition of the filler depending on how well it is developed. For example, it is known that as the bound rubber increases, tan(delta) (@60 C.) is low and the rolling resistance of the rubber decreases.

TABLE-US-00002 TABLE 2 FWHM () I.sub.max () Crystal form Bound Rubber Example 1 6.745 29.2 Amorphous 115 Example 2 6.496 29.2 Amorphous 115 Example 3 6.206 29.1 Amorphous 93 Example 4 6.752 29.2 Amorphous 127 Example 5 FAU-type Example 6 3.872 29.0 Amorphous Example 7 FAU-type Example 8 8.538 23.7 Amorphous

[0170] Referring to Table 2, it was confirmed that the rubber compositions of Preparation Examples 1 to 4, to which the aluminosilicate particles of Examples 1 to 4 were applied, exhibited the bound rubber values of 93 to 127, indicating excellent reinforcing effects.

Experimental Example 4

[0171] The dispersion state of the rubber molded product (Preparation Example 2) to which the aluminosilicate particles of Example 2 were applied and the rubber molded product (Preparation Example 9) to which the silica of Example 9 was applied was observed using a transmission electron microscope. The results are shown in FIG. 14 (a) [Preparation Example 2] and FIG. 14 (b) [Preparation Example 9].

[0172] Referring to FIG. 14, it was confirmed that the aluminosilicate particles of Example 2 exhibited dispersibility of equal to or greater than that of silica in the rubber composition.

Experimental Example 5

[0173] The particle size distribution of primary particles and secondary particles (aggregates) of aluminosilicate or silica dispersed in the rubber compositions of Preparation Examples 2, 3, and 9 was measured using a small-angle X-ray scattering (SAXS).

[0174] Specifically, the beam line image was obtained using u-SAXS beam-line (9A), and particle size analysis was performed using a Beaucage three level model and a sphere model+Beaucage one level model.

TABLE-US-00003 TABLE 3 Particle size Preparation analysis Preparation Ex. 2 Preparation Ex. 3 Ex. 9 Primary particles 16 9 16 (nm) Secondary 60 25 70 particles (nm)

Experimental Example 6

[0175] The dynamic loss factor (tan ) of the rubber molded products of Preparation Examples 2, 3, 4 and 9 was measured under a dynamic strain of 3% and a static strain of 3% using a viscoelasticity measurement apparatus (DMTS 500N, Gabo, Germany). The measured values were normalized based on the value of the rubber molded product of Preparation Example 9, and are shown in Table 4 below.

[0176] For reference, the dynamic loss factor (tan @0 C.) at 0 C. is related to a wet grip property of tires. 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, and it is known that the lower the value, the better the rolling resistance.

TABLE-US-00004 TABLE 4 Preparation Preparation Preparation Preparation Ex. 2 Ex. 3 Ex. 4 Ex. 9 tan @60 C., 107 98 117 100 index tan @0 C., 112 112 120 100 index

[0177] Referring to Table 4, it was confirmed that the rubber molded products according to Preparation Examples 2 to 4 exhibit abrasion resistance and wet grip property of equal to or greater than those of the rubber molded product according to Preparation Example 9.