Method for predicting the rubber reinforcing effect of organic-inorganic composite for rubber reinforcement

Abstract

The present disclosure relates to a method for predicting a rubber reinforcing effect of an organic-inorganic composite for rubber reinforcement. According to the present disclosure, a method for reliably predicting a rubber reinforcing effect of an organic-inorganic composite for rubber reinforcement by thermogravimetric analysis without mixing with a rubber composition is provided.

Claims

1. A method for predicting a rubber reinforcing effect of an organic-inorganic composite, comprising: measuring weight change of an organic-inorganic composite as a function of temperature over a temperature range of 30 C. to 500 C. to perform thermogravimetric analysis (TGA); and determining if the organic-inorganic composite is sufficient for rubber reinforcement based on the following Equation 1 being satisfied:
Da3.0[Equation 1] wherein, in Equation 1, Da is an area under a derivative thermogravimetric curve over a temperature range of 300 C. to 500 C., wherein the derivative thermogravimetric curve is in units of weight reduction percent of the organic-inorganic composite relative to temperature (%/ C.), and wherein the derivative thermogravimetric curve is obtained from the thermogravimetric analysis (TGA) of the organic-inorganic composite.

2. The method for predicting a rubber reinforcing effect of the organic-inorganic composite of claim 1, wherein the organic-inorganic composite for rubber reinforcement comprises an inorganic filler and a coupling agent bonded to at least a part of a surface of the inorganic filler.

3. The method for predicting a rubber reinforcing effect of the organic-inorganic composite of claim 2, wherein the inorganic filler is at least one particle selected from the group consisting of silica, crystalline aluminosilicate, amorphous aluminosilicate, kaolin, clay, and aluminum hydrate.

4. The method for predicting a rubber reinforcing effect of the organic-inorganic composite of claim 2, wherein the coupling agent is at least one compound selected from the group consisting of bis(3-triethoxysilylpropyl) tetrasulfide, bis(2-triethoxy silylethyl) tetrasulfide, bis(4-triethoxysilylbutyl) tetrasulfide, bis(3-trimethoxysilylpropyl) tetrasulfide, bis(2-trimethoxy silylethyl) tetrasulfide, bis(4-trimethoxysilylbutyl) tetrasulfide, bis(3-triethoxysilylpropyl) trisulfide, bis(2-triethoxysilylethyl) trisulfide, bis(4-triethoxysilylbutyl) trisulfide, bis(3-trimethoxysilylpropyl) trisulfide, bis(2-trimethoxy silylethyl) trisulfide, bis(4-trimethoxysilylbutyl) trisulfide, bis(3-triethoxysilylpropyl) disulfide, bis(2-triethoxy silylethyl) disulfide, bis(4-triethoxysilylbutyl) disulfide, bis(3-trimethoxysilylpropyl) disulfide, bis(2-trimethoxy silylethyl) disulfide, bis(4-trimethoxysilylbutyl) disulfide, 3-trimethoxysilylpropyl-N,N-dimethylthiocarbamoyltetrasulfide, 3-triethoxysilylpropyl-N,N-dimethylthiocarbamoyltetrasulfide, 2-triethoxysilylethyl-N,N-dimethylthiocarbamoyltetrasulfide, 2-trimethoxysilylethyl-N,N-dimethylthiocarbamoyltetrasulfide, 3-trimethoxysilylpropylbenzothiazolyltetrasulfide, 3-triethoxysilylpropyl benzothiazole tetrasulfide, 3-trimethoxysilylpropyl methacrylate mono sulfide, and 3-trimethoxysilylpropyl methacrylate mono sulfide.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a graph showing a derivative thermogravimetric curve obtained by thermogravimetric analysis (TGA) of the organic-inorganic composite of Example 1.

(2) FIG. 2 is a graph showing a derivative thermogravimetric curve obtained by thermogravimetric analysis (TGA) of the organic-inorganic composite of Example 2.

(3) FIG. 3 is a graph showing a derivative thermogravimetric curve obtained by thermogravimetric analysis (TGA) of the organic-inorganic composite of Example 3.

(4) FIG. 4 is a graph showing a derivative thermogravimetric curve obtained by thermogravimetric analysis (TGA) of the organic-inorganic composite of Example 4.

(5) FIG. 5 is a graph showing a derivative thermogravimetric curve obtained by thermogravimetric analysis (TGA) of the organic-inorganic composite of Example 5.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(6) 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.

Synthesis Example 1

(7) (Preparation of Amorphous Aluminosilicate Particles)

(8) 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 600 rpm for 40 minutes using an overhead stirrer.

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

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

(11) The washed solid product was dried in an oven at 70 C. for 24 hours to finally obtain aluminosilicate particles (primary particle diameter of 30 nm).

Synthesis Example 2

(12) (Preparation of Crystalline Aluminosilicate Particles)

(13) 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.

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

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

(16) The washed solid product was dried in an oven at 70 C. for 24 hours to finally obtain aluminosilicate particles (primary particle diameter of 150 nm).

Experimental Example 1

(17) (1) The average particle diameter and composition of the aluminosilicate particles according to Synthesis Examples 1 and 2 were confirmed using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS).

(18) As a result, it was confirmed that the aluminosilicate particles of Synthesis Example 1 had a composition of y/x=1.6 and x/n=1.12 in Chemical Formula 1. Also, it was confirmed that the aluminosilicate particles of Synthesis Example 2 had a composition of y/x=1.31 and x/n=0.91 in Chemical Formula 1.

(19) (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 the particles according to Examples 1 and 2 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.

(20) TABLE-US-00001 TABLE 1 Primary particle diameter S.sub.BET S.sub.EXT S.sub.EXT/ V.sub.micro (nm) (m.sup.2/g) (m.sup.2/g) S.sub.BET (cm.sup.3/g) Synthesis Example 1 30 104 89 0.86 0.007 Synthesis Example 2 150 520 190 0.37 0.130

Experimental Example 2

(21) X-ray diffraction analysis for the aluminosilicate particles according to Synthesis Examples 1 and 2 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.

(22) 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. 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).

(23) TABLE-US-00002 TABLE 2 FWHM () I.sub.max () Crystal form Synthesis Example 1 6.745 29.2 amorphous Synthesis Example 2 FAU-type

(24) The aluminosilicate particles of Synthesis Example 2 had a FAU (faujasite) crystal structure, so the FWHM measurement was not performed.

Example 1

(25) 1.0 g of the amorphous aluminosilicate particles obtained in Synthesis Example 1 was added to 20 ml of mesitylene, and heated to 150 C. while stirring at 500 rpm. 0.08 g of bis(3-triethoxysilylpropyl)tetrasulfide (in 1.5 ml of mesitylene) was added thereto, and the mixture was stirred at 150 C. for 20 minutes.

(26) After completion of the stirring, solids were washed four times by centrifugation using toluene, and dried in an oven at 105 C. for 24 hours to obtain an organic-inorganic composite.

Example 2

(27) An organic-inorganic composite was obtained in the same manner as in Example 1, except that the amorphous aluminosilicate obtained in Synthesis Example 1 was pulverized to have a primary particle diameter of 20 nm or less.

Example 3

(28) An organic-inorganic composite was obtained in the same manner as in Example 1, except that the crystalline aluminosilicate particles obtained in Synthesis Example 2 were used instead of the amorphous aluminosilicate particles obtained in Synthesis Example 1.

Example 4

(29) An organic-inorganic composite was obtained in the same manner as in Example 1, except that kaolin clay (product name: Kaolin, manufactured by Sigma-Aldrich) was added instead of the amorphous aluminosilicate particles obtained in Synthesis Example 1.

Example 5

(30) An organic-inorganic composite was obtained in the same manner as in Example 1, except that silica particles (product name: 7000GR, manufactured by Evonik) was added instead of the amorphous aluminosilicate particles obtained in Synthesis Example 1.

Experimental Example 3

(31) The organic-inorganic composites according to Examples 1 to 5 were subjected to thermogravimetric analysis using a thermogravimetric analyzer (STA 449 F3 Jupiter, NETZSCH) as follows.

(32) The base value is set by performing three times thermogravimetric analysis at a heating rate of 5 C./min in the range of 30 to 500 C. under an argon gas atmosphere. 10 to 20 mg of the above-mentioned organic-inorganic composite in a powder form was loaded into a special crucible and subjected to thermogravimetric analysis under the same experimental conditions.

(33) Derivative thermogravimetric curves converted from data obtained by the above analysis were obtained from the thermogravimetric analyzer, and are shown in FIG. 1 (Example 1), FIG. 2 (Example 2), FIG. 3 (Example 3), FIG. 4 (Example 4), and FIG. 5 (Example 5), respectively.

(34) The peak position ( C.) at which the silane coupling agent is desorbed from the organic-inorganic composite is shown in Table 3 below.

(35) Further, in the derivative thermogravimetric curve, an area (Da) of a region where the x-axis value is 300 to 500 C. and the y-axis value is zero (0) or more was obtained by the thermogravimetric analyzer, and is shown in Table 3 below.

(36) However, in case of kaolin clay, weight loss due to hydroxyl groups on a particle surface occurs at 400 C. or higher. Therefore, the Da value for the organic-inorganic composite of Example 4 to which kaolin clay was applied was limited to a temperature range of 300 to 400 C.

(37) TABLE-US-00003 TABLE 3 Peak position ( C.) Da Example 1 409.7 3.88 Example 2 413.1 4.21 Example 3 432.4 2.66 Example 4 372.4 2.47 Example 5 409.4 4.50

(38) Referring to Table 3, the organic-inorganic composites of Examples 1, 2, and 5 had a Da value of 3.0 or more, and satisfied Equation 1.

(39) On the other hand, the organic-inorganic composites of Examples 3 and 4 had a Da value of less than 3.0, and thus did not satisfy Equation 1.

Preparation Example 1

(40) 737.24 g of a diene elastomer mixture (SSBR 2550, LG Chemical) and 375.32 g of the organic-inorganic composite according to Example 1 as a reinforcing material were added to a closed mixer. After mixing them at 150 C. for 5 minutes, 78.66 g of other additives (antioxidant, emulsifier, vulcanization accelerator, wax, etc.) were added thereto and mixed for 90 seconds.

(41) 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).

Preparation Example 2

(42) A rubber molded product was obtained in the same manner as in Preparation Example 1, except that the organic-inorganic composite according to Example 2 was added as a reinforcing material.

Preparation Example 3

(43) A rubber molded product was obtained in the same manner as in Preparation Example 1, except that the organic-inorganic composite according to Example 3 was added as a reinforcing material.

Preparation Example 4

(44) A rubber molded product was obtained in the same manner as in Preparation Example 1, except that the organic-inorganic composite according to Example 4 was added as a reinforcing material.

Preparation Example 5

(45) A rubber molded product was obtained in the same manner as in Preparation Example 1, except that the organic-inorganic composite according to Example 5 was added as a reinforcing material.

Experimental Example 4

(46) The relative volume loss index was measured according to DIN ISO 4649 using an abrasion tester (Bareiss GmbH) for the rubber molded products according to Preparation Examples 1 to 5.

(47) The relative volume loss index was calculated by the following equation for the rubber molded products of Preparation Examples 1 to 4, after determining the rubber molded product of Preparation Example 5 including the organic-inorganic composite of a control example as a reference material.

(48) The relative volume loss index={[(the relative volume loss of Preparation Example 5)(the relative volume loss of the corresponding Preparation Example)]/[the relative volume loss of Preparation Example 5)100]}+100

(49) TABLE-US-00004 TABLE 4 Relative volume loss index (%) Preparation Example 1 86 Preparation Example 2 89 Preparation Example 3 37 Preparation Example 4 24 Preparation Example 5 100

(50) Referring to Table 4, it was confirmed that the rubber molded products of Preparation Examples 1, 2, and 5 to which the organic-inorganic composite of Example 1, 2, or 5 was applied exhibited excellent abrasion resistance of twice or more as compared with the rubber molded products of Preparation Examples 3 and 4 to which the organic-inorganic composite of Example 3 or 4 was applied.

(51) As a result, it was confirmed that the above Equation 1 according to the present disclosure reliably predicts the rubber reinforcing effect of the organic-inorganic composite for rubber reinforcement.