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, 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.aN.sub.b[(AlO.sub.2).sub.x,(SiO.sub.2).sub.y].Math.m(H.sub.2O)[Chemical Formula 1] 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; N is a NH.sub.4.sup.+ ion; 0<a<1, 0<b<1, x>0, y>0, and m0; and 1.0y/x5.0.

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

(1) FIG. 1 is a SEM image of the aluminosilicate particles according to Example 1, Example 2, and Reference Example 1.

(2) FIG. 2 is a graph showing the results of X-ray diffraction analysis of the aluminosilicate particles according to Example 1, Example 2, and Reference Example 1.

(3) FIG. 3 is an infrared spectroscopy spectrum of the aluminosilicate particles according to Example 1, Example 2, and Reference Example 1.

(4) FIG. 4 is a graph showing the results of specific surface area analysis of the aluminosilicate particles according to Example 1, Example 2, and Reference Example 1.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(5) 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

(6) 22 g of KOH (Daejung Chemicals & Metals) and 27 g of colloidal silica (Ludox HS 30 wt %, Sigma-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.

(7) This was cured at room temperature of about 25 C. for 24 hours.

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

(9) The washed cured product was dried in an oven at 70 C. to obtain amorphous aluminosilicate particles.

(10) 1 g of the aluminosilicate was added to a 0.1 M NH.sub.4Cl aqueous solution, stirred for 24 hours, washed twice by centrifugation, and then dried in an oven at 70 C. to obtain ammonium ion-substituted aluminosilicate particles (a=0.7, b=0.3 in Chemical Formula 1).

(11) SEM shape analysis and EDS composition analysis confirmed that the aluminosilicate particles were particles of about 20 nm having a composition of y/x=2.19, a/x=0.45 in Chemical Formula 1.

(12) As a result of XRD analysis, the aluminosilicate particles had FWHM of 6.530 and 2@I.sub.max of 29.2 in the 2 range of 20 to 37.

(13) As a result of specific surface area analysis, it was confirmed that the aluminosilicate particles had S.sub.BET of 111 m.sup.2/g, S.sub.EXT of 99 m.sup.2/g, S.sub.EXT/S.sub.BET of 0.89, and V.sub.micro of 0.004 cm.sup.3/g.

(14) In addition, as a result of FT-IR spectroscopy analysis, the spectrum of the NH bond was observed in the aluminosilicate particles, and the other spectra were observed in the same manner as in Reference Example 1. As a result, it was confirmed that the aluminosilicate of Example 1 was substituted with an NH bond without any structural change as compared with Reference Example 1.

Example 2

(15) 22 g of KOH (Daejung Chemicals & Metals) and 27 g of colloidal silica (Ludox HS 30 wt %, Sigma-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.

(16) This was cured at room temperature of about 25 C. for 24 hours.

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

(18) The washed cured product was dried in an oven at 70 C. to obtain amorphous aluminosilicate particles.

(19) 1 g of the aluminosilicate was added to a 1.0 M NH.sub.4Cl aqueous solution, stirred for 24 hours, washed twice by centrifugation, and then dried in an oven at 70 C. to obtain ammonium ion-substituted aluminosilicate particles (a=0.2, b=0.8 in Chemical Formula 1).

(20) SEM shape analysis and EDS composition analysis confirmed that the aluminosilicate particles were particles of about 20 nm having a composition of y/x=2.08, a/x=0.47 in Chemical Formula 1.

(21) As a result of XRD analysis, the aluminosilicate particles had FWHM of 6.457 and 2@I.sub.max of 29.2 in the 2 range of 20 to 37.

(22) As a result of specific surface area analysis, it was confirmed that the aluminosilicate particles had S.sub.BET of 112 m.sup.2/g, S.sub.EXT of 101 m.sup.2/g, S.sub.EXT/S.sub.BET Of 0.90, and V.sub.micro of 0.004 cm.sup.3/g.

(23) In addition, as a result of FT-IR Spectroscopy analysis, it was confirmed that the aluminosilicate particles exhibited the same intensity variation as in Example 1. Considering this characteristic, it is expected that the concentration of ammonium ions applied to the preparation of aluminosilicate particles does not greatly affect the substitution, but rather the amount of ammonium ions that can be substituted is limited depending on material characteristics.

Reference Example 1

(24) 22 g of KOH (Daejung Chemicals & Metals) and 27 g of colloidal silica (Ludox HS 30 wt %, Sigma-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.

(25) This was cured at room temperature of about 25 C. for 24 hours.

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

(27) The washed cured product was dried in an oven at 70 C. to obtain amorphous aluminosilicate particles (a=1.0, b=0 in Chemical Formula 1).

(28) SEM shape analysis and EDS composition analysis confirmed that the aluminosilicate particles were particles of about 20 nm having a composition of y/x=1.61, a/x=0.83 in Chemical Formula 1.

(29) As a result of XRD analysis, the aluminosilicate particles had FWHM of 6.496 and 2@I.sub.max of 28.5 in the 2 range of 20 to 37.

(30) As a result of specific surface area analysis, it was confirmed that the aluminosilicate particles had S.sub.BET of 126 m.sup.2/g, S.sub.EXT of 108 m.sup.2/g, S.sub.EXT/S.sub.BET of 0.86, and V.sub.micro of 0.007 cm.sup.3/g.

Reference Example 2

(31) Silica (product name: 7000GR) manufactured by Evonic was prepared.

(32) The silica had 2@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.

Reference Example 3

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

(34) The aluminosilicate had an amorphous structure in general, but some crystalline structures were mixed and exhibited an XRD pattern (FWHM=8.538, 2@I.sub.max=23.7 in the 2 range of 20 to 37 of XRD) that was different from the particles according to Examples 1 and 2. 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.

(35) 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.

Reference Example 4

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

(37) 1 g of the aluminosilicate was added to a 0.1 M NH.sub.4Cl aqueous solution, stirred for 24 hours, washed twice by centrifugation, and then dried in an oven at 70 C. to obtain ammonium ion-substituted aluminosilicate particles (a=0.7, b=0.3 in Chemical Formula 1).

(38) The aluminosilicate had an amorphous structure in general, but some crystalline structures were mixed and exhibited an XRD pattern (FWHM=7.717, 2@I.sub.max=23.7 in the 2 range of 20 to 37 of XRD) that was different from the particles according to Examples 1 and 2. Further, it was confirmed that the aluminosilicate had a composition of M=Na, y/x=8.56, a/x=0.18 in Chemical Formula 1.

(39) The aluminosilicate of about 20 nm was subjected to specific surface area analysis, and the results were S.sub.BET=87.75 m.sup.2/g, S.sub.EXT=72.75 m.sup.2/g, S.sub.EXT/S.sub.BET=0.83, and V.sub.micro=0.006 cm.sup.3/g.

Reference Example 5

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

(41) 1 g of the aluminosilicate was added to a 1.0 M NH.sub.4Cl aqueous solution, stirred for 24 hours, washed twice by centrifugation, and then dried in an oven at 70 C. to obtain ammonium ion-substituted aluminosilicate particles (a=0.2, b=0.8 in Chemical Formula 1).

(42) The aluminosilicate had an amorphous structure in general, but some crystalline structures were mixed and exhibited an XRD pattern (FWHM=7.573, 2@I.sub.max=23.7 in the 2 range of 20 to 37 of XRD) that was different from the particles according to Examples 1 and 2. Further, it was confirmed that the aluminosilicate had a composition of M=Na, y/x=8.56, and a/x=0.06 in Chemical Formula 1.

(43) The aluminosilicate of about 20 nm was subjected to specific surface area analysis, and the results were S.sub.BET=87.49 m.sup.2/g, S.sub.EXT=73.18 m.sup.2/g, S.sub.EXT/S.sub.BET=0.84, and V.sub.micro=0.006 cm.sup.3/g.

Preparation Example 1

(44) 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.

(45) 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).

(46) A bound rubber value of the rubber composition prepared according to Preparation Example 1 was measured as 162. 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

(47) 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.

Preparation Example 3

(48) 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 Reference Example 1 were added as a reinforcing material.

(49) The bound rubber value of the rubber composition prepared according to Preparation Example 3 was measured as 103.

Preparation Example 4

(50) 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 Reference Example 2 were added as a reinforcing material.

Preparation Example 5

(51) A rubber composition was obtained in the same manner as in Preparation Example 1, except that the aluminosilicate particles according to Reference Example 3 were added as a reinforcing material.

(52) However, the rubber composition according to Preparation Example 5 was unable to produce a molded product, because the rubber was decomposed at the time of compounding.

Preparation Example 6

(53) A rubber composition was obtained in the same manner as in Preparation Example 1, except that the aluminosilicate particles according to Reference Example 4 were added as a reinforcing material.

(54) However, the rubber composition according to Preparation Example 6 was unable to produce a molded product, because the rubber was decomposed at the time of compounding.

Preparation Example 7

(55) A rubber composition was obtained in the same manner as in Preparation Example 1, except that the aluminosilicate particles according to Reference Example 5 were added as a reinforcing material.

(56) However, the rubber composition according to Preparation Example 7 was unable to produce a molded product, because the rubber was decomposed at the time of compounding.

Experimental Example 1

(57) The average primary particle diameter and composition of the particles according to the examples and reference examples were confirmed using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The photographed SEM images are sequentially shown in FIG. 1 (a) [Example 1], FIG. 1 (b) [Example 2], and FIG. 1 (c) [Reference Example 1].

(58) 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.

(59) The EDS was operated under conditions of 15 kV and a working distance of 15 mm.

(60) TABLE-US-00001 TABLE 1 Composition (Chemical Formula 1) a b y/x a/x Example 1 0.7 0.3 2.19 0.45 Example 2 0.2 0.8 2.08 0.47 Ref. Example 1 1.0 0 1.61 0.83 Ref. Example 3 1.0 0 8.63 1.05 Ref. Example 4 0.7 0.3 8.56 0.18 Ref. Example 5 0.2 0.8 8.56 0.06

Experimental Example 2

(61) 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 reference 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.

(62) 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 isotherm ads/des graph like FIG. 4. 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.

(63) TABLE-US-00002 TABLE 2 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 20 111 99 0.89 0.004 Example 2 20 112 101 0.90 0.004 Ref. Example 1 20 126 108 0.86 0.007 Ref. Example 2 20 175 144 0.82 0.012 Ref. Example 3 20 82.49 74.59 0.90 0.003 Ref. Example 4 20 87.75 72.75 0.83 0.006 Ref. Example 5 20 87.49 73.18 0.84 0.006

Experimental Example 3

(64) X-ray diffraction analysis for each aluminosilicate particle according to Examples and Reference 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.

(65) The measured range of 2 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.

(66) The data plots of Example 1 and Reference Example 1 obtained by X-ray diffraction are shown in FIG. 1

(67) 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).

(68) TABLE-US-00003 TABLE 3 FWHM () I.sub.max () Crystal form Example 1 6.530 29.2 Amorphous Example 2 6.457 29.2 Amorphous Ref. Example 1 6.496 28.5 Amorphous Ref. Example 3 8.538 23.7 Amorphous Ref. Example 4 7.717 23.7 Amorphous Ref. Example 5 7.573 23.7 Amorphous

Experimental Example 4

(69) The absorbance within a wavenumber of 600 to 4000 cm.sup.1 was measured under an ATR (attenuated total reflectance) IR mode condition using an infrared spectroscopy (FTS 3000) to analyze the aluminosilicate particles according to Examples 12 and Reference Example 1. The results are shown in FIG. 3.

Experimental Example 5

(70) A Time-Domain NMR (Minispec) was used to obtain signal decay over time by setting the application mode to sc-Ic-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.

(71) 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.

(72) TABLE-US-00004 TABLE 4 Prep. Ex. 1 Prep. Ex. 2 Prep. Ex. 3 Prep. Ex. 4 Reinforcing Example 1 Example 2 Ref. Ex. 1 Ref. Ex. 2 material Bound rubber 162 165 103 100

(73) Referring to Table 4, it was confirmed that the rubber compositions of Preparation Examples 1 and 2, to which the aluminosilicates of the examples were applied, exhibited higher bound rubber values than the case in which the aluminosilicate of Reference Example 1 or the silica of Reference Example 2 was applied, indicating excellent reinforcing effects.