Quality management method for diisononyl phthalate, method for producing resin composition, resin composition, and cable and pipe

Abstract

Provided is a quality management method for diisononyl phthalate, a method for producing a resin composition, a resin composition, and a cable and a pipe, which enable selection of DINP so that it can further improve properties such as embrittlement properties when added as a plasticizer for vinyl chloride resin. According to an embodiment of the present invention, a quality management method for diisononyl phthalate includes: a measurement step of measuring a Raman spectrum by irradiating diisononyl phthalate with laser light; and a pass / fail determination step of determining whether or not the quality of the diisononyl phthalate is acceptable based on the intensity relationship between a first peak attributed to the vibration of a straight-chain hydrocarbon molecular chain and a second peak attributed to the vibration of an isopropyl group in the Raman spectrum.

Description

TECHNICAL FIELD

[0001] The present application relates to a quality management method for diisononyl phthalate, a method for producing a resin composition, a resin composition, and a cable and a tube. BACKGROUND

[0002] Nowadays, as a method for plasticizing a hard vinyl chloride resin, a method of adding a phthalate-based plasticizer such as diethylhexyl phthalate (DEHP), diisononyl phthalate (DINP) is known (for example, refer to Patent Document 1).

[0003] On the other hand, from the viewpoint of environmental correspondence, activities to replace DEHP, which has been conventionally used, with DINP have been activated.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT DOCUMENTS

[0006] Patent Document 1: International Publication No. 2016 / 031063 SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] The alcohol that is a raw material of DEHP is 2-ethylhexanol that is produced from naphtha, propylene, and n-butyraldehyde. Therefore, even if DEHP produced by different manufacturers is used, the performance of the vinyl chloride resin mixture of the vinyl chloride resin to which DEHP is added varies little.

[0009] However, the alcohol that is a raw material of DINP, i.e., isononyl alcohol, is produced from a complex process of naphtha, B-B fraction (C4), RAF (residual liquid) 1, RAF 2, n-butylenes, and octenes, and isomers are easily produced. Therefore, when DINP produced by different manufacturers is used, variations in properties such as embrittlement properties are easily caused.

[0010] An object of the present application is to provide a quality management method for diisononyl phthalate that can further improve properties such as embrittlement properties when added as a plasticizer for a vinyl chloride resin, a resin composition containing a vinyl chloride resin to which DINP is added and having excellent properties such as embrittlement properties, a method for producing the resin composition, and a cable or a tube having an insulator formed from the resin composition.

[0011] METHOD FOR SOLVING THE PROBLEMS

[0012] The present application aims to solve the above problems and provide a quality management method for diisononyl phthalate, comprising: a measurement step of measuring a Raman spectrum by irradiating diisononyl phthalate with laser light; and a pass / fail determination step of determining whether the diisononyl phthalate is of a quality that is acceptable or not based on the intensity relationship between a first peak attributed to the vibration of a straight-chain hydrocarbon molecular chain and a second peak attributed to the vibration of an isopropyl group in the Raman spectrum.

[0013] Effects of the Invention

[0014] According to the present application, it is possible to provide a quality management method for diisononyl phthalate (DINP) that can further improve brittle characteristics and the like when added as a plasticizer for a vinyl chloride resin, a resin composition containing a vinyl chloride resin to which DINP is added and having excellent brittle characteristics and the like, a method for producing the same, and a cable or a pipe having an insulator formed of the resin composition. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 In the drawings, Figure 1 (a) to (c) are structural formulas of DINP;

[0016] Figure 2 In the drawings, Figure 2 (a) is a perspective view showing a configuration example of a cable according to the present embodiment, Figure 2 (b) is a perspective view showing a configuration example of a pipe according to the present embodiment;

[0017] Figure 3 In the drawings, Figure 3 (a) to (c) are Raman spectra of Samples 1 to 3 measured in the range of 200 to 1350 cm －1

[0018] Figure 4 In the drawings, Figure 4 (a) is a graph in which the range of 750 to 950 cm －1 of the Raman spectrum of Sample 1 is enlarged, Figure 4 (b) shows a plurality of peaks separated by spectral separation analysis using a Pseudo-voigt function in the range of 750 to 950 cm －1 of the Raman spectrum of Sample 1;

[0019] Figure 5 In the drawings, Figure 5 (a) is a graph in which the range of 750 to 950 cm －1 of the Raman spectrum of Sample 2 is enlarged, Figure 5 (b) shows a plurality of peaks separated by spectral separation analysis using a Pseudo-voigt function in the range of 750 to 950 cm － ​(a) is a graph showing the Raman spectrum of frozen sample 1 with amplification in the range of 750 to 950 cm

[0020] Figure 6 In this connection, Figure 6 (a) is a graph showing the Raman spectrum of sample 3 with amplification in the range of 750 to 950 cm －1 (a) is a graph showing the Raman spectrum of sample 3 with amplification in the range of 750 to 950 cm Figure 6 (b) shows the Raman spectrum of sample 3 in the range of 750 to 950 cm －1 (a) is a graph showing the Raman spectrum of sample 3 with amplification in the range of 750 to 950 cm

[0021] Figure 7 In this connection, Figure 7 (a) is a graph showing the Raman spectrum of sample 3 with amplification in the range of 750 to 950 cm Figure 7 (b) is a graph showing the Raman spectrum of sample 3 with amplification in the range of 750 to 950 cm

[0022] Figure 8 In this connection, Figure 8 (a) to (c) are Raman spectra of frozen samples 1 to 3 measured in the range of 200 to 1350 cm －1 (a) to (c) are Raman spectra of frozen samples 1 to 3 measured in the range of 200 to 1350 cm

[0023] Figure 9 In this connection, Figure 9 (a) is a graph showing the Raman spectrum of frozen sample 1 with amplification in the range of 750 to 950 cm －1 (a) to (c) are Raman spectra of frozen samples 1 to 3 measured in the range of 200 to 1350 cm Figure 9 (b) shows the Raman spectrum of frozen sample 1 in the range of 750 to 950 cm －1 (a) to (c) are Raman spectra of frozen samples 1 to 3 measured in the range of 200 to 1350 cm

[0024] Figure 10 In this connection, Figure 10 (a) is a graph showing the Raman spectrum of frozen sample 2 with amplification in the range of 750 to 950 cm －1 (a) to (c) are Raman spectra of frozen samples 1 to 3 measured in the range of 200 to 1350 cm Figure 10 (b) shows the Raman spectrum of frozen sample 2 in the range of 750 to 950 cm －1 (a) to (c) are Raman spectra of frozen samples 1 to 3 measured in the range of 200 to 1350 cm

[0025] Figure 11 In this connection, Figure 11(a) is the Raman spectrum of frozen sample 3, specifically the 750–950 cm⁻¹ region. －1 The image obtained by magnifying within the specified range. Figure 11 (b) The Raman spectrum of frozen sample 3 is shown in the range of 750–950 cm⁻¹. －1 The Pseudo-voigt function is used to analyze the separated peaks within the range of the spectrum;

[0026] Figure 12 middle, Figure 12 (a) is a graph showing the ratio of the peak intensity of the first peak to the peak intensity of the second peak and the ratio of the integrated intensity of the first peak to the integrated intensity of the second peak in frozen samples 1 to 3. Figure 12 (b) is a graph showing the ratio of the peak intensity of the second peak to the peak intensity of the first peak and the ratio of the integrated intensity of the second peak to the integrated intensity of the first peak in frozen samples 1 to 3.

[0027] Figure 13 This was done under the condition of a measurement temperature of 26℃, within the range of 0–3250 cm. －1 Raman spectra of samples 1 to 3 were measured within the range of [missing information].

[0028] Figure 14 middle, Figure 14 (a) is a graph showing the relationship between the "peak intensity ratio" and "embrittlement temperature" for each sample shown in Table 3. Figure 14 (b) is a graph showing the relationship between the "integral strength ratio" and "embrittlement temperature" for each specimen shown in Table 3.

[0029] Explanation of reference numerals in the attached figures

[0030] 1: Cable, 11: Conductor, 12: Insulator, 13: Sheath, 2: Pipe, 21: Insulator, 22: Coating. Detailed Implementation

[0031] [Implementation Method]

[0032] (Structure of diisononyl phthalate)

[0033] Diisononyl phthalate (DINP) is a type of phthalate that can be used as a plasticizer in resin products such as polyvinyl chloride (PVC). When DINP is added to PVC, it inserts into the molecular chains of PVC, inhibiting strong inter-chain bonding and thus lowering the embrittlement temperature of PVC.

[0034] Figure 1 (a)~(c) are the structural formulas of DINP. Figure 1 (a) shows the alkyl chain C9H of DINP. 19 It is generally known that this originates from the front end.Figure 1 (c) the branched type alkyl chain structure of monomethyl octanol shown by isopropyl-CH(CH3)2 (hereinafter, referred to as branched type alkyl chain structure) (for example, refer to the above patent document 1). Here, Figure 1 (c) the part surrounded by the dotted line C is the alkyl chain C9H 19 The part surrounded by the dotted line D is isopropyl.

[0035] The present inventors, etc. have found, through analysis using Raman scattering measurement as described later, that the alkyl chain C9H 19 In addition to having the branched type alkyl chain structure, it can also have Figure 1 (b) the linear type alkyl chain structure derived from the linear hydrocarbon molecular chain -(CH2)8-CH3 shown by n-nonyl, the ratio of the branched type alkyl chain structure to the linear type alkyl chain structure differs between DINPs prepared under different conditions (for example, DINPs manufactured by different manufacturers), and as a result, the performance of DINP as a plasticizer differs. Here, in the case of Figure 1 (b) the part surrounded by the dotted line A is the alkyl chain C9H 19 The part surrounded by the dotted line B is the linear hydrocarbon molecular chain.

[0036] Further, the present inventors, etc. have found that the greater the proportion of the linear type alkyl chain structure that the DINP molecule has, that is, the greater the ratio of the number of linear type alkyl chain structures to the number of branched type alkyl chain structures in the DINP, the greater the effect of lowering the embrittlement temperature of the polyvinyl chloride. This is because the DINP molecule having the linear type alkyl chain structure composed of a linear hydrocarbon expands the interval of the molecular chains when entering the molecular chain of the polyvinyl chloride that is the base polymer, and is able to maintain a large interval between the molecular chains even under low temperature conditions, and thus is able to suppress the combination between the molecular chains.

[0037] (Quality management method for diisononyl phthalate)

[0038] According to the quality management method for diisononyl phthalate of the present embodiment, using Raman scattering measurement, it is possible to select, from among a plurality of DINPs prepared under different conditions, one in which the ratio of the number of linear type alkyl chain structures to the number of branched type alkyl chain structures is large. Non-contact analysis is possible by Raman scattering measurement, and it is possible to maintain the original information of the DINP.

[0039] The quality management method for diisononyl phthalate according to the present embodiment includes the following steps: a measurement step of measuring a Raman spectrum by irradiating laser light on DINP; and a pass / fail determination step of determining whether or not the quality of DINP is acceptable based on the magnitude relationship between the intensity (integral intensity or peak intensity) of a first peak attributed to the vibration of the molecular chain of a straight-chain hydrocarbon and the intensity of a second peak attributed to the vibration of an isopropyl group in the measured Raman spectrum.

[0040] Here, the molecular chain of a straight-chain hydrocarbon constitutes a straight-chain alkyl chain structure, and an isopropyl group is contained in the straight-chain alkyl chain structure. Therefore, by measuring the magnitude relationship between the intensity of the first peak and the intensity of the second peak, it is possible to know the magnitude relationship between the number of branched-chain alkyl chain structures and the number of straight-chain alkyl chain structures in DINP.

[0041] The first peak is a peak in the Raman spectrum at 880 cm －1 The peak having the maximum intensity is in the range of 900 cm －1 The peak having the maximum intensity is in the range of 860 cm －1 The peak having the maximum intensity is in the range of 860 cm －1 The peak having the maximum intensity is in the range of 860 cm

[0042] For the first peak and the second peak, since the measurement is performed while being buried in a waveform synthesized from a plurality of peaks attributed to different molecular vibrations, peak separation is performed by spectral separation analysis to obtain the respective Raman shifts (cm －1 ). The spectral separation analysis can use a statistical distribution function such as a Pseudo-voigt function, a Lorentz function, or a Gaussian distribution function.

[0043] In the pass / fail determination step, for example, in a case where the ratio of the integral intensity of the first peak to the integral intensity of the second peak in the Raman spectrum measured under the condition of a measurement temperature of 26°C is 0.3 or more, it is determined that the quality of the DINP as the measurement target is acceptable. Also, for example, in a case where the ratio of the peak intensity of the first peak to the peak intensity of the second peak in the Raman spectrum measured under the condition of a measurement temperature of 26°C is 0.67 or more, it is determined that the quality of the DINP as the measurement target is acceptable. As long as the ratio of the integral intensity of the first peak to the integral intensity of the second peak is 0.3 or more, or the ratio of the peak intensity of the first peak to the peak intensity of the second peak is 0.67 or more, the brittle temperature of polyvinyl chloride to which DINP is added as a plasticizer can be sufficiently reduced.

[0044] Here, the peak height and the integrated intensity of the first peak and the second peak are obtained by calculation from the peak shape obtained by spectral separation analysis (fitting analysis) using the above-described statistical distribution function, and are obtained after background correction of the peak shape. The background correction is performed to remove the influence of the background of light that is not derived from the branched structure of DINP but is derived from fluorescence, Rayleigh scattering and Mie scattering of the irradiated laser light, and interference light other than the irradiated laser light, and the background profile (baseline) obtained by fitting analysis using a polynomial function, a spline function or the like is removed from the above-described peak shape. In addition, the integration range in the calculation of the integrated intensity of the first peak and the second peak is the range between the two intersection points of the above-described peak shape and the background profile.

[0045] Note that, in the case where all the alkyl chains of the DINP molecules in DINP are straight-chain alkyl chain structures, the intensity of the second peak is zero, and thus the ratio of the integrated intensity of the first peak to the integrated intensity of the second peak in the Raman spectrum measured at a measurement temperature of 26°C has no upper limit in theory. However, in reality, it is impossible that all the alkyl chains are straight-chain alkyl chain structures, and the ratio is almost never more than 1, and is 0.8 or less in most cases.

[0046] (Resin composition and method for producing the same)

[0047] The resin composition according to the present embodiment is a resin composition in which polyvinyl chloride in which DINP determined to be acceptable by the quality management method for diisononyl phthalate described above is added as a main component. That is, the method for producing the resin composition according to the present embodiment includes a step of adding DINP determined to be acceptable by the quality management method for diisononyl phthalate described above to polyvinyl chloride. Note that, in the step of adding DINP to polyvinyl chloride, liquid DINP (for example, at 10°C to 35°C) is added to polyvinyl chloride.

[0048] The resin composition according to the present embodiment contains, for example, polyvinyl chloride and DINP added to the polyvinyl chloride, the ratio of the integrated intensity of the first peak to the integrated intensity of the second peak in the Raman spectrum measured when a laser light is irradiated to measure the Raman spectrum at a measurement temperature of 26°C being 0.3 or more. In addition, the other resin composition according to the present embodiment contains, for example, polyvinyl chloride and DINP added to the polyvinyl chloride, the ratio of the peak intensity of the first peak to the peak intensity of the second peak in the Raman spectrum measured when a laser light is irradiated to measure the Raman spectrum at a measurement temperature of 26°C being 0.67 or more.

[0049] The resin composition according to the present embodiment can take various forms depending on the use thereof. For example, in the case where it is used as an insulator for a cable or a pipe, it is processed into a tubular shape, and in the case where it is used as an agricultural film, it is processed into a sheet shape.

[0050] (cable or pipe structure)

[0051] The resin composition according to the present embodiment can be used as a material for an insulator of a cable, a pipe. An example of the configuration of a cable or a pipe having an insulator formed of the resin composition according to the present embodiment is shown below.

[0052] Figure 2 (a) shows a perspective view of an example of the configuration of a cable 1 according to the present embodiment. The cable 1 includes a conductor 11, an insulator 12 covering the outer periphery of the conductor 11, and a sheath 13 covering the outer periphery of the insulator 12. The conductor 11 is configured of a conductor such as copper, and a twisted wire formed of a plurality of conductive wires can be used as the conductor 11. The insulator 12 is formed of an insulator such as foamed polyethylene. The sheath 13 is formed of the resin composition according to the present embodiment described above. The cable 1 can be used, for example, as a cable for electric wire or for medical use.

[0053] Figure 2 (b) is a perspective view showing an example of the configuration of a pipe 2 according to the present embodiment. The pipe 2 includes a hollow linear insulator 21 and a plating layer 22 covering the outer periphery of the insulator 21. The insulator 21 is formed of the resin composition according to the present embodiment described above. The plating layer 22 is formed of a metal such as copper. The pipe 2 can be used, for example, as a waveguide pipe or the like.

[0054] (effects of the embodiment)

[0055] According to the above-described embodiment, it is possible to provide a quality management method of DINP, diisononyl phthalate, which can improve properties such as embrittlement properties when DINP is used as a plasticizer of a vinyl chloride resin. According to the quality management method of DINP, it is possible to predict the embrittlement temperature of the vinyl chloride resin into which DINP is blended before the DINP is blended into the vinyl chloride resin, and thus it is possible to improve the production speed and yield of the product of the vinyl chloride resin into which DINP is blended, a cable, a pipe, or the like using the same.

[0056] In addition, according to the above-described embodiment, it is possible to provide a resin composition containing a vinyl chloride resin to which DINP is added and having excellent properties such as embrittlement properties, and a method for producing the same. In addition, according to the above-described embodiment, it is possible to provide a cable or a pipe having an insulator formed of a resin composition having excellent properties such as embrittlement properties. In addition, the quality management method of DINP, the method for producing a resin composition, and the like according to the above-described embodiment can be applied to material development using material informatics (MI) that analyzes data using machine learning, artificial intelligence (AI), or the like.

[0057] Example

[0058] First, three kinds of DINP (denoted as Samples 1 to 3) prepared under different conditions were prepared, and Raman scattering measurement was performed. The Raman scattering measurement was performed using a RAMAN force Standard VIS-NIR-HS manufactured by Nippon Denshi Co., Ltd. under the following conditions: laser wavelength of 532 nm, width of entrance slit of spectrometer of 50 μm, number of lines of diffraction grating of 1200 gr / mm (center frequency of measurement frequency range of 800 cm －1 ), ratio of light quantity after attenuation to maximum light quantity of laser with respect to ND filter (attenuation ratio) of 190 / 255, and measurement temperature of 26°C. Samples 1 to 3 were liquid (DINP was liquid at 26°C), and laser was irradiated in a state of being charged in an aluminum container (aluminum pan).

[0059] Figure 3 (a) to (c) are Raman spectra of Samples 1 to 3 measured in a range of 200 to 1350 cm －1 . In these Raman spectra, a peak at approximately 1040 cm － 1 is a peak derived from symmetric stretching of C-O-C, and a peak at approximately 1280 cm －1 is a peak derived from νC-O stretching.

[0060] Figure 4 (a), Figure 5 (a), Figure 6 (a) are graphs obtained by enlarging a range of 750 to 950 cm －1 ( Figure 3 range surrounded by a broken line in (a) to (c)) in Raman spectra of Sample 1, Sample 2, and Sample 3, respectively.

[0061] Figure 4 (b), Figure 5 (b), Figure 6 (b) show a plurality of peaks separated by spectral separation analysis (fitting analysis) using a Pseudo-voigt function in a range of 750 to 950 cm －1 in Raman spectra of Sample 1, Sample 2, and Sample 3, respectively.

[0062] Figure 4 Among the peaks separated by spectral separation analysis shown in (b), a peak PI taking a maximum value at approximately 893 cm － 1 is a first peak belonging to vibration (CC stretching) of a molecular chain of a straight-chain hydrocarbon, and a peak P2 taking a maximum value at approximately 847 cm －1 2 is a second peak belonging to vibration (CC symmetric stretching) of an isopropyl group.

[0063] Figure 5 Among the peaks separated by spectral separation analysis shown in (b), a peak PI taking a maximum value at approximately 893 cm​－1 The peak P1 taking a maximum value is a first peak belonging to the vibration (CC stretch) of the molecular chain of the linear hydrocarbon, at approximately 849 cm －1 The peak P2 taking a maximum value is a second peak belonging to the vibration (CC symmetric stretch) of the isopropyl group.

[0064] Figure 6 (b) is a graph showing the results of the spectral separation analysis of the Raman spectrum of the frozen sample 1. The peak P1 taking a maximum value is a first peak belonging to the vibration (CC stretch) of the molecular chain of the linear hydrocarbon, at approximately 849 cm －1 The peak P1 taking a maximum value is a first peak belonging to the vibration (CC stretch) of the molecular chain of the linear hydrocarbon, at approximately 846 cm －1 The peak P2 taking a maximum value is a second peak belonging to the vibration (CC symmetric stretch) of the isopropyl group.

[0065] In the following Table 1, the results of the spectral separation analysis of the Raman spectrum of the above-mentioned liquid samples 1 to 3 are shown. The "peak intensity ratio" in the table is the ratio of the peak intensity (peak height) of the first peak to that of the second peak, and the "integral intensity ratio" is the ratio of the integral intensity of the first peak to that of the second peak.

[0066] Table 1

[0067]

[0068] Figure 7 (a) is a graph showing the ratio of the peak intensity of the first peak to that of the second peak and the ratio of the integral intensity of the first peak to that of the second peak of the samples 1 to 3. Figure 7 (b) is a graph showing the ratio of the peak intensity of the second peak to that of the first peak and the ratio of the integral intensity of the second peak to that of the first peak of the samples 1 to 3.

[0069] Next, the Raman scattering measurement was performed on the samples 1 to 3 in the frozen state by liquid nitrogen. The measurement conditions were constant except for the measurement temperature (the temperature of the samples 1 to 3 at the time of measurement).

[0070] Figure 8 (a) to (c) are the Raman spectra of the frozen samples 1 to 3 measured in the range of 200 to 1350 cm －1 The peak at approximately 1040 cm －1 in these Raman spectra is a peak derived from the C-O-C symmetric stretch, and the peak at approximately 1280 cm －1 is a peak derived from the vC-O stretch.

[0071] Figure 9 (a), Figure 10 (a), Figure 11 (a) are the Raman spectra of the frozen sample 1, the sample 2, and the sample 3, respectively, in the range of 750 to 950 cm －1Scope ( Figure 8 The diagram obtained by enlarging the area enclosed by the dashed lines (a) to (c).

[0072] Figure 9 (b) Figure 10 (b) Figure 11 (b) The Raman spectra of frozen samples 1, 2, and 3 in the range of 750–950 cm⁻¹ are shown respectively. －1 The Pseudo-voigt function is used to perform spectral separation analysis (fit analysis) within a certain range to separate multiple peaks.

[0073] Figure 9 (b) shows the peak obtained by spectral separation analysis, at approximately 894 cm⁻¹. －1 The peak P1, which has the highest value, is the first peak of the vibration (CC stretching) of the molecular chain of straight-chain hydrocarbons, approximately 849 cm⁻¹. －1 Peak P2, which has the maximum value, is the second peak belonging to the vibration (CC symmetric stretching) of isopropyl.

[0074] Figure 10 (b) shows the peak obtained by spectral separation analysis, at approximately 894 cm⁻¹. －1 The peak P1, which has the highest value, is the first peak of the vibration (CC stretching) of the molecular chain of straight-chain hydrocarbons, approximately 852 cm⁻¹. －1 Peak P2, which has the maximum value, is the second peak belonging to the vibration (CC symmetric stretching) of isopropyl.

[0075] Figure 11 (b) shows the peak obtained by spectral separation analysis, at approximately 894 cm⁻¹. －1 The peak P1, which has the highest value, is the first peak of the vibration (CC stretching) of the molecular chain of straight-chain hydrocarbons, approximately 846 cm⁻¹. －1 Peak P2, which has the maximum value, is the second peak belonging to the vibration (CC symmetric stretching) of isopropyl.

[0076] Table 2 below shows the spectral separation and analysis results of the Raman spectra of the frozen samples 1-3 mentioned above. In the table, "peak intensity ratio" is the ratio of the peak intensity (peak height) of the first peak to the peak intensity of the second peak, and "integral intensity ratio" is the ratio of the integrated intensity of the first peak to the integrated intensity of the second peak.

[0077] Table 2

[0078]

[0079] Figure 12 (a) is a graph showing the ratio of the peak intensity of the first peak to the peak intensity of the second peak and the ratio of the integrated intensity of the first peak to the integrated intensity of the second peak for frozen samples 1 to 3. Figure 12(b) is a graph showing the ratio of the peak intensity of the second peak to the peak intensity of the first peak and the ratio of the integrated intensity of the second peak to the integrated intensity of the first peak of the frozen samples 1 to 3.

[0080] Figure 13 is a Raman spectrum of the samples 1 to 3 measured in the range of 0 to 3250 cm －1 at a measurement temperature of 26°C. According to Figure 13 , in the Raman spectra of the sample 2 and the sample 3, a broad fluorescence spectrum spanning approximately 700 to 2000 cm －1 can be confirmed. From this result, it can be inferred that the higher the proportion of branched alkyl chain structures in the DINP, the more the structure of the molecular chain portion of -C9H 19 becomes unstable, the occurrence of defect levels increases, and thus the fluorescence is enhanced. Conversely, the more the linear alkyl chain structures in the DINP, the less the proportion of branched alkyl chain structures, and thus it can be inferred that the fluorescence is weakened.

[0081] Next, the samples 1 and 3 in a liquid state (26°C) and the frozen samples 1 and 3 were added to a vinyl chloride resin, respectively, and the embrittlement temperature of the vinyl chloride resin was measured.

[0082] The ratio of the peak intensity of the first peak to the peak intensity of the second peak (peak intensity ratio in the table) of the Raman spectra of the samples 1 and 3 in a liquid state and the frozen samples 1 and 3, the ratio of the integrated intensity of the first peak to the integrated intensity of the second peak (integrated intensity ratio in the table), the respective compounding amount (compounding ratio in the table) with respect to 100 parts by mass of the vinyl chloride resin, and the embrittlement temperature of the vinyl chloride resin after compounding are shown in Table 3 below.

[0083] Table 3

[0084]

[0085] Figure 14 (a) is a graph showing the relationship between the "peak intensity ratio" and the "embrittlement temperature" of each sample shown in Table 3. Figure 14 (b) is a graph showing the relationship between the "integrated intensity ratio" and the "embrittlement temperature" of each sample shown in Table 3.

[0086] Table 3, Figure 14 (a) and (b) show the correlation between the intensity ratio of the first peak and the second peak of the Raman spectrum of the DINP and the embrittlement temperature of the vinyl chloride resin when the DINP is compounded in the vinyl chloride resin. For example, Table 3, Figure 14(b) shows that DINP, which has a ratio of the integrated intensity of the first peak to the integrated intensity of the second peak determined at a measurement temperature of 26°C of approximately 0.3 or more, can effectively reduce the embrittlement temperature.

[0087] (Summary of Embodiments)

[0088] Hereinafter, the technical ideas grasped from the above-described embodiments are described with reference to the reference signs in the embodiments. However, the reference signs and the like in the following description do not limit the components in the claims to the components specifically shown in the embodiments.

[0089] [1] A quality management method of diisononyl phthalate, comprising a measurement step and a pass / fail determination step; in the measurement step, a Raman spectrum is measured by irradiating diisononyl phthalate with laser light; in the pass / fail determination step, based on a size relationship between an intensity of a first peak in the Raman spectrum that belongs to a vibration of a molecular chain of a straight-chain hydrocarbon and an intensity of a second peak that belongs to a vibration of an isopropyl group, a quality of the diisononyl phthalate is determined to be pass or fail.

[0090] [2] The quality management method of diisononyl phthalate according to the above item [1], the first peak is a peak having a maximum intensity in a range of 880 cm －1 900 cm －1 The second peak is a peak having a maximum intensity in a range of 840 cm －1 860 cm －1 The second peak is a peak having a maximum intensity in a range of 840 cm

[0091] [3] The quality management method of diisononyl phthalate according to the above item [1] or [2], in the pass / fail determination step, in a case where a ratio of an integrated intensity of the first peak determined at a measurement temperature of 26°C to an integrated intensity of the second peak is 0.3 or more, the quality of the diisononyl phthalate is determined to be pass.

[0092] [4] The quality management method of diisononyl phthalate according to the above item [1] or [2], in the pass / fail determination step, in a case where a ratio of a peak intensity of the first peak determined at a measurement temperature of 26°C to a peak intensity of the second peak is 0.67 or more, the quality of the diisononyl phthalate is determined to be pass.

[0093] [5] A method for producing a resin composition, comprising a step of adding, to polyvinyl chloride, the diisononyl phthalate judged to be acceptable by the quality management method for the diisononyl phthalate according to any one of the above items [1] to [4].

[0094] [6] A resin composition, comprising polyvinyl chloride and diisononyl phthalate added to the polyvinyl chloride, the diisononyl phthalate having a ratio of an integral intensity of a first peak attributed to vibration of a molecular chain of a straight-chain hydrocarbon to an integral intensity of a second peak attributed to vibration of an isopropyl group in a Raman spectrum measured at a measurement temperature of 26°C of 0.3 or more.

[0095] [7] A resin composition, comprising polyvinyl chloride and diisononyl phthalate added to the polyvinyl chloride, the diisononyl phthalate having a ratio of a peak intensity of a first peak attributed to vibration of a molecular chain of a straight-chain hydrocarbon to a peak intensity of a second peak attributed to vibration of an isopropyl group in a Raman spectrum measured at a measurement temperature of 26°C of 0.67 or more.

[0096] [8] The resin composition according to the above item [6] or [7], the first peak being a peak having the maximum intensity in a range of 880 cm －1 900 cm －1 the second peak being a peak having the maximum intensity in a range of 840 cm －1 860 cm －1 900 cm.

[0097] [9] A cable or pipe, comprising an insulator (13, 21) formed of the resin composition according to any one of the above items [6] to [8].

[0098] The above describes the embodiments and examples of the present application, but the present application is not limited to the above-described embodiments and examples, and various modifications can be made within the scope of the present application. For example, instead of Raman scattering measurement, nuclear magnetic resonance (NMR) can be performed and a spectrum can be analyzed to study the magnitude relationship between the number of branched alkyl chain structures and the number of straight-chain alkyl chain structures in DINP.

[0099] In addition, the above-described embodiments and examples are not intended to limit the invention in the claims. In addition, it should be noted that all the described combinations of features in the embodiments and examples are not limited to being means necessary for solving the problems of the invention.

Claims

1. A quality management method for diisononyl phthalate, comprising: The measurement procedure involves irradiating various diisononyl phthalate products prepared under different conditions with a laser and measuring their Raman spectra. The pass / fail determination step is based on the intensity relationship between the first peak of the vibration of the straight-chain hydrocarbon molecular chain and the second peak of the vibration of the isopropyl group in the Raman spectrum, to determine whether the quality of the various diisononyl phthalates is qualified. In the pass / fail determination step, if the ratio of the integrated intensity of the first peak to the integrated intensity of the second peak, measured at a temperature of 26°C, is 0.3 or higher, the quality of the diisononyl phthalate is determined to be qualified.

2. A quality management method for diisononyl phthalate, comprising: The measurement procedure involves irradiating various diisononyl phthalate products prepared under different conditions with a laser and measuring their Raman spectra. The pass / fail determination step is based on the intensity relationship between the first peak of the vibration of the straight-chain hydrocarbon molecular chain and the second peak of the vibration of the isopropyl group in the Raman spectrum, to determine whether the quality of the various diisononyl phthalates is qualified. In the pass / fail determination step, if the ratio of the peak intensity of the first peak to the peak intensity of the second peak, measured at a temperature of 26°C, is greater than or equal to 0.67, the quality of the diisononyl phthalate is determined to be qualified.

3. The quality management method for diisononyl phthalate according to claim 1 or 2, wherein, The first peak is at 880 cm⁻¹ in the Raman spectrum. －1 Above 900cm －1 The peak with the highest intensity is selected from the following range, wherein the second peak is at 840 cm⁻¹ in the Raman spectrum. － 1 and above 860cm －1 Take the peak with the highest intensity from the following range.

4. A method for preparing a resin composition, comprising: The step of adding diisononyl phthalate, which is determined to be qualified by the quality management method of diisononyl phthalate according to any one of claims 1 to 3, to polyvinyl chloride.

5. A resin composition comprising polyvinyl chloride and diisononyl phthalate, wherein the diisononyl phthalate is added to the polyvinyl chloride, and when the diisononyl phthalate is irradiated with a laser at a measurement temperature of 26°C to determine the Raman spectrum, the ratio of the integrated intensity of the first peak of the vibration of the linear hydrocarbon molecular chain to the integrated intensity of the second peak of the vibration of the isopropyl group in the Raman spectrum is 0.3 or more.

6. A resin composition comprising polyvinyl chloride and diisononyl phthalate, wherein the diisononyl phthalate is added to the polyvinyl chloride, and when the diisononyl phthalate is irradiated with a laser at a measurement temperature of 26°C to determine the Raman spectrum, the ratio of the peak intensity of the first peak of the vibration of the linear hydrocarbon molecular chain to the peak intensity of the second peak of the vibration of the isopropyl group in the Raman spectrum is 0.67 or higher.

7. The resin composition according to claim 5 or 6, wherein, The first peak is at 880 cm⁻¹ in the Raman spectrum. －1 Above 900cm －1 The peak with the highest intensity is selected from the following range, wherein the second peak is at 840 cm⁻¹ in the Raman spectrum. －1 Above 860cm －1 Take the peak with the highest intensity from the following range.

8. A cable or pipe having an insulator formed from the resin composition of any one of claims 5 to 7.

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