A method and system for evaluating resin compatibility with rubber

Abstract

The present application relates to the field of rubber industry materials, and particularly relates to a method and system for quantitatively evaluating the compatibility of a resin and rubber blending system, which comprises solvent extraction to preliminarily separate the resin and rubber mixture, thermogravimetric analysis (TGA) to detect the content of residual incompatible resin, dynamic shear rheology (DSR) testing to obtain the compatibility parameters of tan delta curve, and Fox equation combined with differential scanning calorimetry (DSC) to determine the difference between actual and theoretical glass transition temperature (Tg). The method realizes accurate quantification of the compatibility of resin and rubber, and improves the efficiency of rubber formulation development and material performance.

Description

Technical Field

[0001] This invention relates to the field of rubber industrial materials, and in particular to a method and system for quantitative assessment of the compatibility of resin-rubber blends. Specifically, it relates to a comprehensive compatibility evaluation technique based on solvent extraction, thermogravimetric analysis (TGA), dynamic shear rheological analysis (DSR), and Fox equation combined with differential scanning calorimetry (DSC). Background Technology

[0002] In modern rubber industry, especially in tires, drive belts, and rubber products, resins are often blended with rubber as modifying additives to significantly improve the processing performance, wear resistance, wet grip, and rolling resistance of rubber materials. However, different types of resins have varying compatibility with rubber, and the compatibility of different resins with the rubber matrix directly affects the final performance of rubber products. Generally, resins with good compatibility can be fully dispersed in the rubber matrix, improving the overall performance of the rubber; while resins with poor compatibility may precipitate or agglomerate, leading to performance degradation or even failure of the rubber material.

[0003] Traditional methods for assessing resin-rubber compatibility primarily employ solvent extraction, which involves selectively extracting the resin and rubber using a specific organic solvent and evaluating their compatibility based on the residual mass after extraction. However, this method is overly simplistic and suffers from insufficient accuracy: on the one hand, it may overestimate the compatibility between the resin and rubber; on the other hand, it fails to accurately reflect the actual microscopic phase characteristics and thermodynamic compatibility after mixing.

[0004] Currently, there is a lack of comprehensive quantitative assessment methods and systems in this field that can accurately and reliably evaluate the compatibility of resin-rubber systems. Therefore, developing a new comprehensive analytical method to accurately evaluate the degree of compatibility between resin and rubber has become an important technical requirement in the rubber industry. Summary of the Invention

[0005] To address the aforementioned technical problems, the present invention aims to provide a quantitative assessment method for the compatibility of resin-rubber blends. By combining solvent extraction, thermogravimetric analysis (TGA), dynamic shear rheology analysis (DSR), and Fox equation combined with differential scanning calorimetry (DSC), a comprehensive analytical system is established. This system can objectively quantify the compatibility between resin and rubber, providing a scientific basis for the rational selection of resins and the optimization of rubber formulations in the rubber industry, thereby improving the overall performance and development efficiency of rubber materials.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A method for evaluating the compatibility of resin and rubber, characterized by comprising the following steps: 1) Solvent extraction was used to initially separate the compatible resin portion from the resin-rubber mixture, yielding the residual rubber matrix; 2) Perform thermogravimetric analysis (TGA) on the residual rubber matrix obtained in step 1) to determine the mass loss in the range of 100–300 °C and to determine whether there is incompatible resin. 3) Dynamic shear rheology (DSR) test was used to measure the hysteresis factor tanδ curve of the resin-rubber mixture in the temperature range of -120℃ to 100℃, and the compatibility slope and correlation coefficient R² were calculated. 4) Calculation of the theoretical glass transition temperature Tg of the resin-rubber mixture based on the Fox equation: 1 / Tg=W 树脂 / Tg 树脂 +W 橡胶 / Tg 橡胶 ; Among them, W 树脂 and W 橡胶 These represent the mass fractions of resin and rubber, respectively, and Tg. 树脂 and Tg 橡胶 These are the glass transition temperatures of the resin and the rubber, respectively. 5) The actual glass transition temperature of the mixture is measured by differential scanning calorimetry (DSC). If the difference between the two values ​​is less than 5°C, it is determined that the resin and rubber have good compatibility.

[0007] Preferably, the solvent in step 1) is methylene chloride or n-hexane, and the resin-rubber mixture is soaked in the solvent and stirred for 12 to 24 hours.

[0008] Preferably, in step 1), the solvent is removed by vacuum evaporation, and the mass of the residual rubber matrix is ​​weighed to calculate the compatible portion.

[0009] Preferably, the thermogravimetric analysis (TGA) in step 2) is performed under a nitrogen atmosphere, with the temperature heated to 600°C at a rate of 10°C / min.

[0010] Preferably, if the mass loss in step 2) exceeds 5%, it is determined that the resin and rubber are incompatible.

[0011] Preferably, in step 3), the frequency of the dynamic shear rheology (DSR) test is 10 Hz, the strain range is 0.1% to 10.0%, and the closer the compatibility slope value is to 1, the better the compatibility.

[0012] Furthermore, the present invention also provides a system for quantitatively evaluating the compatibility of resin and rubber, the system implementing the method comprising: a) Solvent extraction apparatus for the preliminary separation of the compatible resin fraction from the resin-rubber mixture; b) Thermogravimetric analyzer, used to determine the mass loss of incompatible resin in the residual rubber matrix after extraction in the range of 100-300℃; c) Dynamic shear rheometer, used to measure the hysteresis factor tanδ curve of resin-rubber mixtures and calculate the compatibility slope and correlation coefficient R². d) Differential scanning calorimeter, used to determine the actual glass transition temperature Tg of resin-rubber mixtures.

[0013] Preferably, the solvent extraction device uses methylene chloride or n-hexane as the extraction solvent, and the extraction time is 12 to 24 hours.

[0014] Preferably, the thermogravimetric analyzer is heated from room temperature to 600°C at a heating rate of 10°C / min under a nitrogen protective atmosphere.

[0015] Preferably, the dynamic shear rheometer has a test temperature range of -120℃ to 100℃, a frequency of 10Hz, and a strain range of 0.1% to 10.0%.

[0016] By employing the aforementioned technical solutions, this invention proposes a quantitative evaluation method and system for resin-rubber compatibility. Through a combination of organic solvent extraction, thermogravimetric analysis (TGA), dynamic shear rheology analysis (DSR), and Fox equation combined with differential scanning calorimetry (DSC), a comprehensive quantitative evaluation system is formed. Compared to traditional single solvent extraction methods, the technical solution of this invention has the following significant technical advantages: (1) Improve the accuracy of assessment: TGA can accurately identify residual incompatible resins and avoid overestimation of resin compatibility by traditional methods; DSR analysis can obtain the slope and correlation coefficient of the tanδ curve to quantify the micro-phase characteristics of the mixture and objectively reflect the true compatibility of the resin and rubber system.

[0017] (2) Achieve quantitative analysis: The theoretical glass transition temperature (Tg) is calculated using the Fox equation, and the actual Tg value is measured by DSC. By comparing the two, the thermodynamic compatibility between the resin and the rubber can be accurately determined, thus realizing the transformation of compatibility evaluation from qualitative to quantitative.

[0018] (3) Improve the efficiency of rubber formulation design: This comprehensive evaluation method can quickly and accurately screen out resins with good compatibility with the rubber matrix, guide the optimization of rubber formulation, effectively reduce R&D costs and shorten the R&D cycle.

[0019] (4) Improve the performance of rubber materials: Through the accurate quantitative evaluation of the present invention, resins with better compatibility with rubber can be selected, thereby significantly improving the overall performance of rubber products, such as wet grip, rolling resistance and wear resistance.

[0020] In summary, by establishing a scientific and accurate comprehensive compatibility evaluation system, this invention effectively overcomes the shortcomings of existing technologies and provides important technical support for the selection of resins and material design in the rubber industry. Detailed Implementation

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present invention.

[0022] The method of this invention includes four key steps: 1. Solvent extraction method: Take 10g of resin-rubber mixture and place it in 100mL of methylene chloride. Stir for 12 hours. Remove the solvent by vacuum evaporation, weigh the mass of the residual rubber matrix, and calculate the compatible portion.

[0023] 2. Thermogravimetric analysis (TGA): The sample was placed in a TGA instrument (TA Instruments Q500) and heated to 600℃ under nitrogen atmosphere. The mass loss between 100-300℃ was recorded. If the loss was significant (>5%), the resin and rubber were considered incompatible.

[0024] 3. Dynamic Shear Rheology (DSR) Analysis: DSR testing using TA Instruments Discovery HR-2: Temperature range: -120℃ to 100℃; Frequency: 10Hz; Calculate Slope and R 2 If the slope is close to 1, the resin and rubber have good compatibility.

[0025] 3. Fox equation combined with DSC test: Computational Theory Tg: 1 / Tg=W 树脂 / Tg 树脂 +W 橡胶 / Tg 橡胶 ; Among them, W 树脂 and W 橡胶These represent the mass fractions of resin and rubber, respectively, and Tg. 树脂 and Tg 橡胶 These are the glass transition temperatures of the resin and the rubber, respectively. 4. Use DSC to measure the experimental Tg. If the deviation between the experimental Tg and the theoretical Tg is less than 5℃, it is judged that the resin and rubber have good compatibility.

[0026] Example 1 A 10g sample was prepared by mixing terpene resin and rubber. The mixture was placed in 100mL of methylene chloride and stirred at room temperature for 12 hours. The solvent was then removed by vacuum evaporation, and the mass of the residual rubber matrix was weighed. The compatibility fraction of the resin was calculated. The residual rubber matrix was subjected to a TGA test. Heating to 600℃ at a rate of 10℃ / min under a nitrogen atmosphere, the mass loss in the 100-300℃ range was measured to be 1.5%. Next, a dynamic shear rheometer was used to measure the tanδ curve within the range of -120℃ to 100℃ at a frequency of 10Hz. The slope value was calculated to be 0.95 and the correlation coefficient R² was 0.98 through linear fitting. Finally, the theoretical glass transition temperature (Tg) of the resin-rubber mixture was calculated to be -53℃ using the Fox equation, and the actual Tg value measured by DSC was -52℃. The difference between the two values ​​was only 1℃, indicating high compatibility between the resin and rubber.

[0027] Example 2 The same experimental steps were performed using C9 hydrocarbon resin. After solvent extraction, the resin content was 7.5 phr. The mass loss measured by TGA at 100-300℃ was 3.8%. The slope value obtained by DSR was 0.75, and the R² value was 0.92. The theoretical Tg of the Fox equation was -55℃, and the actual Tg measured by DSC was -50℃. The difference between the two was 5℃, indicating that the compatibility between the resin and the rubber was moderate.

[0028] Example 3 The same test was performed using hydrogenated DCPD resin. After solvent extraction, the resin content was 8.2 phr, the TGA mass loss was 2.5%, the slope measured by DSR was 0.85, the R² was 0.95, the theoretical Tg of the Fox equation was -50℃, and the actual Tg measured by DSC was -51℃. The difference between the two was 1℃, which confirmed high compatibility.

[0029] Comparative Example 1 The same test was performed using nonpolar C5 resin. After extraction, the resin content was 4.2 phr, the TGA mass loss was 8.5%, the DSR measured slope was 0.45, the R² was 0.85, the theoretical Tg of the Fox equation was -60℃, and the actual Tg measured by DSC was -45℃, with a deviation of 15℃, indicating low compatibility.

[0030] Comparative Example 2 The resin with a high softening point was used for testing. After solvent extraction, the resin content was 5.1 phr, the TGA mass loss was 6.7%, the slope measured by DSR was 0.55, the R² was 0.88, the theoretical Tg of the Fox equation was -57℃, and the actual Tg measured by DSC was -47℃, with a deviation of 10℃. It was determined that the resin and rubber had low compatibility.

[0031] The experimental data from the above embodiments and comparative examples are summarized below: Sample number Types of resins Resin content (phr) after solvent extraction TGA quality loss (%) DSRSlope DSRR² Fox equation theory Tg (°C) DSC measured Tg (°C) Compatibility evaluation Example 1 Terpene resins 9.8 1.5 0.95 0.98 -53 -52 high Example 2 C9 hydrocarbon resin 7.5 3.8 0.75 0.92 -55 -50 middle Example 3 Hydrogenated DCPD resin 8.2 2.5 0.85 0.95 -50 -51 high Comparative Example 1 Non-polar C5 resin 4.2 8.5 0.45 0.85 -60 -45 Low Comparative Example 2 High softening point resin 5.1 6.7 0.55 0.88 -57 -47 Low The foregoing description of embodiments of the present invention, through which those skilled in the art are able to implement or use the present invention, will be readily apparent to those skilled in the art. Various modifications to these embodiments will be readily apparent to those skilled in the art. The general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novelty disclosed herein.

Claims

1. A method for evaluating the compatibility of resin and rubber, characterized in that, Includes the following steps: 1) Solvent extraction was used to initially separate the compatible resin portion from the resin-rubber mixture, yielding the residual rubber matrix; 2) Perform thermogravimetric analysis (TGA) on the residual rubber matrix obtained in step 1) to determine the mass loss in the range of 100–300 °C and to determine whether there is incompatible resin. 3) Dynamic shear rheology (DSR) test was used to measure the hysteresis factor tanδ curve of the resin-rubber mixture in the temperature range of -120℃ to 100℃, and the compatibility slope and correlation coefficient R² were calculated. 4) Calculation of the theoretical glass transition temperature Tg of the resin-rubber mixture based on the Fox equation: 1 / Tg=W 树脂 / Tg 树脂 +W 橡胶 / Tg 橡胶 ; Among them, W 树脂 and W 橡胶 These represent the mass fractions of resin and rubber, respectively, and Tg. 树脂 and Tg 橡胶 These are the glass transition temperatures of the resin and the rubber, respectively. 5) The actual glass transition temperature of the mixture is measured by differential scanning calorimetry (DSC). If the difference between the two values ​​is less than 5°C, it is determined that the resin and rubber have good compatibility.

2. The method according to claim 1, characterized in that, The solvent in step 1) is methylene chloride or n-hexane, and the resin-rubber mixture is soaked in the solvent and stirred for 12 to 24 hours.

3. The method according to claim 1, characterized in that, Step 1) Remove the solvent by vacuum evaporation and weigh the remaining rubber matrix to calculate the compatible portion.

4. The method according to claim 1, characterized in that, Step 2) The thermogravimetric analysis (TGA) was performed under a nitrogen atmosphere, with the temperature heated to 600°C at a rate of 10°C / min.

5. The method according to claim 1, characterized in that, If the mass loss exceeds 5% in step 2), the resin and rubber are deemed incompatible.

6. The method according to claim 1, characterized in that, In step 3), the frequency of the dynamic shear rheology (DSR) test is 10 Hz, the strain range is 0.1% to 10.0%, and the closer the compatibility slope value is to 1, the better the compatibility.

7. A system for quantitatively evaluating the compatibility of resin and rubber, characterized in that, The system implements the method according to any one of claims 1-6, comprising: a) Solvent extraction apparatus for the preliminary separation of the compatible resin fraction from the resin-rubber mixture; b) Thermogravimetric analyzer, used to determine the mass loss of incompatible resin in the residual rubber matrix after extraction in the range of 100-300℃; c) Dynamic shear rheometer, used to measure the hysteresis factor tanδ curve of resin-rubber mixtures and calculate the compatibility slope and correlation coefficient R². d) Differential scanning calorimeter, used to determine the actual glass transition temperature Tg of resin-rubber mixtures.

8. The system according to claim 7, characterized in that, The solvent extraction device uses methylene chloride or n-hexane as the extraction solvent, and the extraction time is 12 to 24 hours.

9. The system according to claim 7, characterized in that, The thermogravimetric analyzer was heated from room temperature to 600°C at a heating rate of 10°C / min under a nitrogen protective atmosphere.

10. The system according to claim 7, characterized in that, The dynamic shear rheometer has a test temperature range of -120℃ to 100℃, a frequency of 10Hz, and a strain range of 0.1% to 10.0%.