Methods of classifying resins

Abstract

To provide a method for classifying resins that have a wide variety of chemical structures. [Solution] A method for classifying at least two resins, comprising: a purification step of removing volatile components by heat-treating the resins to be classified at a temperature lower than their respective decomposition temperatures; a decomposition step of obtaining thermal decomposition products by thermally decomposing the resins to be classified at a temperature higher than their respective decomposition temperatures; an analysis step of separating and analyzing the thermal decomposition products using a two-dimensional gas chromatograph-mass spectrometer; a table creation step of creating a table by assigning the peaks appearing in each two-dimensional chromatogram obtained after the analysis step and aligning the two-dimensional chromatograms; and a classification step of classifying each resin by performing multivariate analysis based on the created table.

Description

Technical Field

[0001] The present invention relates to a method for classifying resins.

Background Art

[0002] For example, many rubber products such as pneumatic tires are manufactured by using a rubber composition as a raw material and vulcanizing it. Many compounding agents are added to the rubber composition for improving physical properties, and a large amount of resins such as hydrocarbon-based resins are also compounded.

[0003] Resins have various uses in addition to being a compounding agent for tires as a material for improving braking performance (hereinafter also referred to as "WETμ") on a wet road surface. Therefore, resins having various chemical structures have been developed. However, regarding the chemical structure of resins, it has been common to obtain information on rough monomer species by analysis using thermal decomposition gas chromatography, and there has been a limit to detailed structural classification. Resins may have greatly different physical properties depending on slight differences in the type and amount of monomers. There is a need for a method to obtain detailed classification information and finally associate it with the physical properties of the vulcanized rubber obtained.

[0004] Patent Document 1 below describes a quantitative method for individually quantifying the content of each resin component in a paste containing multiple resin components and inorganic powder, comprising: a dissolution step of mixing the paste with an organic solvent to dissolve the multiple resin components; a separation step of separating the inorganic powder from the solution obtained in the dissolution step to form a resin solution containing the multiple resin components; a measurement step of measuring the resin solution by pyrolysis gas chromatography to determine the peak area value of the pyrolysis product unique to each resin component produced by the pyrolysis of each resin component; a quantitative step of calculating the content in the paste from the peak area value obtained in the measurement step, based on a calibration curve showing the correlation between the content and the peak area value of the unique pyrolysis product for each resin component; and a drying step between the separation step and the measurement step of heating the resin solution at a temperature above the boiling point of the organic solvent and below the pyrolysis temperature of the multiple resin components, drying it to volatilize the organic solvent, and forming a dry solid containing the multiple resin components, wherein in the measurement step, the dry solid is measured by pyrolysis gas chromatography. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Patent No. 6950494 [Overview of the project] [Problems that the invention aims to solve]

[0006] The inventors of this invention have diligently investigated the matter and found that the above-mentioned prior art merely quantifies the resin components and does not constitute a detailed structural classification. Therefore, there is a need to establish a method that can obtain detailed resin classification information and link it to the physical properties of the resulting vulcanized rubber.

[0007] This invention has been made in view of the above circumstances, and its purpose is to provide a method for classifying resins that can classify resins having a wide variety of chemical structures.

[0008] The above problems can be solved by the following configuration. That is, the present invention relates to a method for classifying at least two or more resins, comprising: a purification step of removing volatile components by heat-treating the resins to be classified at a temperature lower than their respective decomposition temperatures; a decomposition step of obtaining thermal decomposition products by thermally decomposing the resins to be classified at a temperature higher than their respective decomposition temperatures; an analysis step of separating and analyzing the thermal decomposition products using a two-dimensional gas chromatograph-mass spectrometer; a table creation step of creating a table by assigning the peaks appearing in each two-dimensional chromatogram obtained after the analysis step and aligning the two-dimensional chromatograms; and a classification step of performing multivariate analysis based on the created table to classify each resin (1).

[0009] In the above resin classification method (1), the resin classification method (2) is preferred, in which the temperature range in which the heat treatment is performed in the purification step is 100°C to 300°C.

[0010] In the above resin classification method (1) or (2), the resin classification method (3) is preferred, in which the temperature range for performing the thermal decomposition treatment in the decomposition step is 400°C to 700°C.

[0011] In any of the above resin classification methods (1) to (3), the resin classification method (4) is preferred, in which the first column used in the two-dimensional gas chromatograph mass spectrometer is a nonpolar column and the second column is a medium-polar or highly polar column.

[0012] Of the above resin classification methods (1) to (4), the resin classification method (5) in which the resin is a hydrocarbon resin is preferred. [Effects of the Invention]

[0013] Conventional pyrolysis gas chromatography analysis has only been able to identify some of the numerous pyrolysis products as resin monomers by assigning them to specific peaks, resulting in only a rough classification. This is because assigning all the peaks requires considerable effort, and in one-dimensional chromatography, peaks overlap, making thorough analysis impossible.

[0014] On the other hand, the resin classification method according to the present invention successfully separates and assigns many peaks by using a two-dimensional gas chromatograph-mass spectrometer, and furthermore, by statistically analyzing the created peak list, the resins can be classified in more detail. Furthermore, the resin classification method according to the present invention includes a purification step in which volatile components are removed by heating the resin to be classified at a temperature lower than the decomposition temperature, before carrying out the decomposition step in which the resin to be classified is thermally decomposed at a temperature higher than the decomposition temperature to obtain each thermal decomposition product. This makes it possible to classify and analyze the main skeleton of the resin without being affected by impurities or antioxidants in the resin, and the resins can be classified with greater accuracy. [Brief explanation of the drawing]

[0015] [Figure 1] 3D plot display results of principal component analysis of resins A to J [Modes for carrying out the invention]

[0016] The present invention relates to a method for classifying at least two resins, comprising: a purification step of removing volatile components by heat-treating the resins to be classified at a temperature lower than their respective decomposition temperatures; a decomposition step of obtaining thermal decomposition products by thermally decomposing the resins to be classified at a temperature higher than their respective decomposition temperatures; an analysis step of separating and analyzing the thermal decomposition products using a two-dimensional gas chromatograph-mass spectrometer; a table creation step of creating a table by assigning the peaks appearing in each of the two-dimensional chromatograms obtained after the analysis step and aligning the two-dimensional chromatograms; and a classification step of classifying each resin by performing multivariate analysis based on the created table. Each step will be described below.

[0017] The present invention provides a method for classifying at least two resins. The resins to be classified in this invention are preferably hydrocarbon resins, such as petroleum resins. Hydrocarbon resins are oligomers or polymers polymerized from olefin monomers (mainly petroleum fractions). For example, when hydrocarbon resins are blended into a rubber composition that is a raw material for vulcanized rubber for tires, line effects such as WETμ can be expected. The resins to be classified are at least two, and there is no particular upper limit on the number of resins. However, in the table creation process described later, when assigning peaks appearing in a two-dimensional chromatogram and aligning the two-dimensional chromatograms, it is preferable to limit the number of resins to be classified to around 10 or less in order to avoid excessive complexity.

[0018] <Purification process> In the purification process, volatile components are removed by heat-treating the resin to be classified at a temperature lower than its decomposition temperature. In this invention, it is preferable that the resin is a hydrocarbon resin, and in the purification process, it is preferable to heat-treat it at a temperature lower than the decomposition temperature of the hydrocarbon resin, specifically 100°C to 300°C. By performing the purification process, volatile components such as low-molecular-weight compounds mixed in the resin during the synthesis or separation process of the resin to be classified can be removed, thereby improving the accuracy of the final resin classification.

[0019] < decomposition process > In the decomposition process, the resin to be classified is thermally decomposed at a temperature higher than each decomposition temperature to obtain respective pyrolyzates. In the present invention, it is preferable that the resin is a hydrocarbon resin, and in the decomposition process, the temperature range for carrying out the thermal decomposition treatment is preferably 400°C to 700°C.

[0020] < analysis process > In the analysis process, the pyrolyzates of the resin to be classified are separated and analyzed using a two-dimensional gas chromatography mass spectrometer. The two-dimensional gas chromatography can perform temperature control on independent first and second columns individually and carry out temperature-programmed analysis. In the present invention, it is preferable that the first column used is a non-polar column and the second column is a medium-polar column or a high-polar column. Also, the first column and the second column are preferably connected via a modulator. The modulator cryotraps the volatile components separated by the first column into the column using cold gas cooled by liquid nitrogen, concentrates the peak bands for a certain time (about 5 to 10 seconds), and then sends them to the second column.

[0021] In the table creation process, the attribution of the peaks appearing in each two-dimensional chromatogram obtained after the analysis process and the alignment between the two-dimensional chromatograms are carried out to create a table. The table can be created, for example, by taking samples in the vertical arrangement (rows) and peaks in the horizontal arrangement (columns) and matrixing their respective intensities.

[0022] < classification process > In the classification process, multivariate analysis is carried out based on the table creation process and the created table to classify each resin. Examples of the method for carrying out multivariate analysis include principal component analysis known to those skilled in the art. By, for example, displaying the results of principal component analysis in a three-dimensional plot, the resin to be classified can be classified.

[0023] In the resin classification method according to the present invention, by using a two-dimensional gas chromatograph mass spectrometer, many peaks are successfully separated and assigned, and by statistically analyzing the created peak list, the resin can be classified in more detail. Therefore, it is useful as a classification method for resins whose physical properties vary greatly depending on the type and amount of monomers, particularly hydrocarbon resins.

Example

[0024] The examples of this invention are described below for more specific explanation.

[0025] As the resins to be classified, ten types of resins, Resin A to Resin J, were prepared. Resin A to Resin J are all hydrocarbon resins. First, by heat-treating at a temperature lower than the decomposition temperature of each of Resin A to Resin J (100°C to 300°C), volatile components were removed (purification step). Next, by thermally decomposing at a temperature higher than the decomposition temperature of each of Resin A to Resin J (400°C to 700°C), respective pyrolyzates were obtained (decomposition step). Next, the pyrolyzates were separated and analyzed using a two-dimensional gas chromatograph mass spectrometer (analysis step). As the two-dimensional gas chromatograph mass spectrometer, "Pegasus4D" manufactured by LECO Corporation was used. The measurement conditions are as follows.

[0026] (Acquisition Rate) 150spectra / s (Acquisition Delay) 1minute (Mass Range) 35 to 600u (Transfer Line Temp.) 270℃ (Ion Source Temperature) 250℃ (First Column(Column 1)) (non-polar column, 30.5m×0.25mm, 0.25μm (Second Column(Column 2)) (middle-polar column or high-polar column, 1.8m×0.18mm, 0.18μm (Column 1 Oven) 40℃5min→5℃ / min→250℃23min (Column 2 Oven) 45℃5min→5℃ / min→255℃23min (Modulation Period) 12s (Modulator Offset) +15℃ (Split Ratio) 70 (Injection) Curie Point pyrolyzer, 590℃ (Carrier Gas) He, 92.3mL / min(constant flow)

[0027] Next, a table was created by assigning the peaks appearing in each two-dimensional chromatogram obtained after the analysis process and aligning the two-dimensional chromatograms, then forming a matrix (table creation process). Finally, principal component analysis (multivariate analysis) was performed based on the table creation process and the created table to classify each resin (classification process). Figure 1 shows the 3D plot display results of the principal component analysis for resins A to J.

[0028] From the results in Figure 1, it can be seen that resins A to J can be broadly classified into three categories: resins A to C, resins D to F, and resins G to I, and that resin J is unique.

Claims

1. A method for classifying at least two resins, comprising: a purification step of removing volatile components by heat-treating the resins to be classified at a temperature lower than their respective decomposition temperatures; a decomposition step of obtaining thermal decomposition products by thermally decomposing the resins to be classified at a temperature higher than their respective decomposition temperatures; an analysis step of separating and analyzing the thermal decomposition products using a two-dimensional gas chromatograph-mass spectrometer; a table creation step of creating a table by assigning peaks appearing in each two-dimensional chromatogram obtained after the analysis step and aligning the two-dimensional chromatograms; and a classification step of classifying each resin by performing multivariate analysis based on the created table.

2. The resin classification method according to claim 1, wherein the temperature range in which the heat treatment is performed in the purification step is 100°C to 300°C.

3. The method for classifying resins according to claim 1, wherein the temperature range in which the thermal decomposition treatment is carried out in the decomposition step is 400°C to 700°C.

4. The resin classification method according to claim 1, wherein the first column used in the two-dimensional gas chromatograph mass spectrometer is a nonpolar column and the second column is a medium-polar or highly polar column.

5. The method for classifying resins according to claim 1, wherein the resin is a hydrocarbon resin.

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