JP6717107B2 - Cross-linking evaluation method for polymer materials - Google Patents

Description

The present invention relates to a cross-linking evaluation method for evaluating the cross-linked state of a polymer material.

BACKGROUND ART Conventionally, an invention relating to a method for measuring and evaluating a phase separation state of a polymer material formed by mixing a plurality of polymer materials is known (see Patent Document 1 below). Further, conventionally, an invention relating to a polymer analysis processing apparatus using an atomic force microscope is known (see Patent Document 2 below).

In the conventional measuring method described in Patent Document 1, a polymer test piece is formed of a polymer material, and the polymer test piece is exposed to an electronic dyeing agent in the form of a gas or an aqueous solution to form an electronic dyeing layer on the polymer test piece. To form. Further, the thickness of the electronically dyed layer that has changed corresponding to the exposure time is measured and the thickness of the electronically dyed layer with respect to the exposure time is converted into data. Then, the layer separation state of the polymer material is measured by the correlation line of the phase separation tendency of the polymer material derived based on the electronically dyed layer thickness with respect to the exposure time which is made into data (see the same document, claim 1, etc.).

The conventional apparatus described in Patent Document 2 is an apparatus that uses an atomic force microscope and has a data acquisition unit, a data processing unit, and an analysis unit. The data acquisition unit acquires the phase data of the polymer obtained by using the non-contact mode of the atomic force microscope. The data processing unit sets a reference part of interest in the phase image created from the phase data, subtracts the phase data of the reference part of interest from the phase data of each part of the phase image, and obtains the relative phase data. To calculate. The analysis unit analyzes the polymer using the relative phase data (see the same document, claim 1, etc.).

According to this conventional apparatus, even if there are subtle changes in the measurement conditions such as the shape and temperature of the sample surface, accurate analysis results can be obtained, and the glass transition temperature, melting point temperature, and crystallization temperature can be accurately measured. It can be obtained well (see the same document, paragraph 0014, etc.).

JP, 2011-169763, A JP, 2010-032255, A

For example, the cross-linking of the polymer material using the silane compound proceeds slowly due to contact with moisture, and therefore can be gradually promoted over a relatively long time in a humid environment. As described above, in the case of the polymer material in which the crosslinking reaction proceeds slowly, a crosslinking evaluation method for determining the completion time of crosslinking and the uniformity of the distribution of crosslinking is required.

Patent Document 1 describes that a sample is observed by a scanning probe microscope (SPM) phase difference image and the phase dispersion structure is evaluated by the SPM phase difference image. However, the contrast due to the unevenness of the sample surface is also superimposed on the SPM phase difference image, and it is not easy to extract quantitative parameters from this two-dimensional image (see the same document, paragraphs 0052 to 0056, etc.).

Further, in the conventional apparatus described in Patent Document 2, it is not possible to determine the completion time of cross-linking or the uniformity of cross-linking distribution in the polymer material in which the cross-linking reaction proceeds slowly.

The present invention has been made in view of the above-mentioned problems, and for example, in a polymer material in which a crosslinking reaction proceeds slowly, it is possible to evaluate the completion time of crosslinking and the uniformity of crosslinking distribution, etc. The purpose is to provide an evaluation method.

In order to achieve the above-mentioned object, the present invention is a cross-linking evaluation method for evaluating the cross-linking state of a polymer material, comprising a histogram creating step of creating a histogram from phase data of the polymer material, and the polymer material based on the histogram. And a cross-linking evaluation step of evaluating the cross-linking state of.

According to the present invention, a cross-linking distribution of a polymer material can be directly observed by creating a histogram from phase data of the polymer material. Furthermore, by evaluating the cross-linking state of the polymer material based on the histogram, for example, in the polymer material in which the cross-linking reaction proceeds slowly, it is possible to determine the completion time of cross-linking, the uniformity of cross-linking distribution, and the molecules of the polymer material The occurrence of side reactions such as crosslinking can be evaluated.

1 is a flow chart of a method for evaluating cross-linking of a polymer material according to an embodiment of the present invention. Sectional drawing which shows an example of the cable which comprises a polymer material as an insulation coating. Sectional drawing which shows an example of the cable which comprises a polymer material as an insulation coating. The flowchart which shows the modification of the crosslinking evaluation method of the polymer material shown in FIG. The schematic block diagram which shows an example of the atomic force microscope used for a phase data acquisition process. The figure which shows an example of the phase data acquired by the phase data acquisition process. The figure which shows an example of the histogram produced by the histogram production process. The figure which shows an example of the phase data acquired by the phase data acquisition process. The figure which shows an example of the phase data acquired by the phase data acquisition process. The figure which shows the histogram created from the phase data shown in FIG. The figure which shows the histogram created from the phase data shown in FIG. The flowchart which shows the modification of the crosslinking evaluation method of the polymer material shown in FIG. The figure which shows an example of the shape data of a polymer material. The figure which shows an example of the phase data of a polymer material. The figure which shows the histogram created from the phase data shown in FIG. The figure which shows an example of the threshold-value (theta)a of the waveform obtained from a histogram. The figure which shows an example of the threshold-value (theta)b of the waveform obtained from a histogram. The figure which shows the phase data whose phase delay is larger than threshold value (theta)a. The figure which shows the phase data whose phase delay is smaller than threshold value (theta)b.

Hereinafter, an embodiment of a method for evaluating cross-linking of a polymer material of the present invention will be described with reference to the drawings.

FIG. 1 is a flow chart of a cross-linking evaluation method S100 of a polymer material according to an embodiment of the present invention. 2 and 3 are cross-sectional views showing an example of the cables 10A and 10B provided with a polymer material as the insulating coating 11.

The cross-linking evaluation method S100 of the polymer material according to the present embodiment is a polymer such as a cross-linked rubber used as a material for the insulation coating 11 of the electric wire or cable 10A, or the outer layer coating 13 for covering the plurality of electric wires or cables 10A having the insulation coating 11. This is a method for evaluating the cross-linked state of a material. Examples of the crosslinked rubber include ethylene propylene rubber, chloroprene rubber, natural rubber, acrylic rubber, butyl rubber, silicone rubber, fluororubber, acrylonitrile/butadiene rubber, styrene/butadiene rubber, chlorinated polyethylene and the like.

These polymer materials are cross-linked by, for example, peroxides, sulfur, metal oxides and the like, and heat treatment is required for cross-linking in any method. For example, the crosslinked rubber used as the insulating coating 11 of the cable 10A is extruded from the extruder to cover the cable 10A, and then crosslinked at a temperature of 100° C. or higher using high temperature high pressure steam or high temperature molten metal salt. .. However, such heating cross-linking requires a lot of energy and requires an expensive heating device.

On the other hand, the moisture-curable polymer material in which the silane coupling agent is introduced into the polymer structure can carry out the crosslinking reaction at room temperature and atmospheric pressure. For example, a silane compound and a free radical generator are introduced into ethylene propylene rubber and grafted to produce a silane graft rubber. This silane-grafted rubber can be extrusion-coated on an electric wire or cable in the presence of a silanol condensation catalyst and brought into contact with water to crosslink. Examples of the compound containing a silane crosslinking group include vinyltrimethoxysilane and the like.

Further, a silane-grafted chloroprene rubber is produced by kneading the chloroprene rubber and the organic silane compound. Using this silane-grafted chloroprene rubber, the electric wires and cables 10A and 10B are extrusion-coated with a masterbatch in which a silanol condensation catalyst is added to chloroprene rubber, and immersed in water at room temperature for crosslinking. In addition, a silane-grafted rubber is produced by reacting chlorinated polyethylene with an organic silane compound in the presence of peroxide. By using this silane-grafted rubber, the electric wires and the cables 10A and 10B are extrusion-coated in the presence of a silanol condensation catalyst, and exposed to water to be crosslinked.

As described above, in a moisture-curable polymer material in which a silane coupling agent is introduced into the polymer structure, such as a silane crosslinked rubber, crosslinking gradually progresses due to contact with water. Moisture-curable polymer materials undergo slow crosslinking even in a humid environment without being immersed in water. Therefore, in such a polymer material, an evaluation method for determining the completion time of cross-linking and evaluating the uniformity of cross-linking distribution is important.

Particularly, in a moisture-curable polymer in which a silane coupling agent is introduced into the polymer structure, a side reaction which is a reaction different from silane crosslinking may occur. For example, when a side reaction in which rubber molecules are cross-linked progresses, the hardness of that portion increases, which causes problems such as poor appearance of the polymer material. Therefore, an evaluation method for quantitatively evaluating the incidence of side reactions is required. The cross-linking evaluation method S100 of the polymer material of the present embodiment is not limited to the cross-linked state of the cross-linked rubber that is cross-linked by heating as described above, but the moisture-curable polymer material in which the silane coupling agent is introduced into the polymer structure as described above. It is particularly effective for evaluating the crosslinked state of.

The cross-linking evaluation method S100 of the polymer material of the present embodiment is a cross-linking evaluation method for evaluating the cross-linking state of the polymer material as described above, and as shown in FIG. And step S20. The histogram creating step S10 is a step of creating a histogram from the phase data of the polymer material to be evaluated, which is obtained in advance. The crosslinking evaluation step S20 is a step of evaluating the crosslinking state of the polymer material to be measured based on the histogram created in the histogram creation step S10.

FIG. 4 is a flow chart showing a modified example of the cross-linking evaluation method S100 of the polymer material of the present embodiment shown in FIG. For example, when the phase data of the polymer material to be evaluated cannot be obtained in advance, the cross-linking evaluation method S100 of the polymer material includes a phase data acquisition step of acquiring phase data in the phase mode of the atomic force microscope before the histogram creation step S10. S30 may be included. Hereinafter, the phase data acquisition step S30 will be described first, and then the histogram creation step S10 and the bridge evaluation step S20 using the phase data will be described.

(Phase data acquisition process)
FIG. 5: is a schematic block diagram which shows an example of the atomic force microscope apparatus 100 which can be used for the phase data acquisition process S30. The atomic force microscope apparatus 100 includes, for example, a cantilever 1, a vibrator 2 that vibrates the cantilever 1 up and down at a predetermined frequency, a laser light source 3 that irradiates the cantilever 1 with a laser beam L, and a laser light source 3 of the cantilever 1. And a light receiving section 4 for receiving the laser light L emitted from the cantilever 1 and reflected by the cantilever 1.

In addition, the atomic force microscope apparatus 100 includes, for example, an analysis personal computer (PC) 5 connected to the oscillator 2 and the light receiving unit 4, a chamber 6 for containing the sample P, and a sample P in the chamber 6. A scanner 7 can be provided that supports and approaches the cantilever 1. The scanner 7 can be composed of, for example, a piezoelectric element.

Further, the atomic force microscope apparatus 100 is connected to the chamber 6 via a vacuum line 8a, is connected to the rotary pump 8 for controlling the pressure in the chamber 6, and is connected to the chamber 6 via a cooling line 9a. And a cooling device 9 for cooling the sample P. Further, the atomic force microscope apparatus 100 can include, for example, the temperature controller 10 for controlling the temperature of the sample P in the chamber 6. The temperature controller 10 may include, for example, a temperature sensor 10a that measures the temperature of the sample P in the chamber 6 and a heater 10b that heats the sample in the chamber 6.

Under the control of the analyzing PC 5, the atomic force microscope apparatus 100 causes the surface of the sample P to approach the cantilever 1 by the scanner 7 to a distance of several nanometers while vibrating the cantilever 1 up and down by the oscillator 2. The atomic force acting between the sample and the sample P is detected. Then, the atomic force microscope apparatus 100 controls the distance between the surface of the sample P and the cantilever 1 by the scanner 7 so that the amplitude of the vibration of the cantilever 1 becomes constant, so that the surface roughness of the sample P becomes uneven. The shape can be measured.

In the phase data acquisition step S30, the measurement area of the sample P is determined, and the phase data of the sample P is acquired according to the phase mode of the atomic force microscope apparatus 100. More specifically, the phase of the cantilever 1 is changed by the action of the atomic force acting between the cantilever 1 and the surface of the sample P. Specifically, laser light L is emitted from the laser light source 3 to the cantilever 1 vibrating with a small distance where an atomic force acts on the surface of the sample P, and the reflected light is received. The light is received by the unit 4, and the vibration of the cantilever 1 is measured by the analyzing PC 5 connected to the light receiving unit 4.

The vibration of the cantilever 1 changes in phase with respect to the vibration of the vibrator 2 depending on the hardness of the measurement site of the sample by the cantilever 1. The phase delay of the vibration of the cantilever 1 with respect to the vibration of the oscillator 2 is small when the measurement point of the sample P is hard, and is large when the measurement point of the sample P is soft. That is, the atomic force microscope apparatus 100 can acquire the phase data including the information on the phase delay depending on the hardness of the measurement point of the sample P by the analysis PC 5.

In the phase data acquisition step S30, the environment inside the chamber 6 is set to a temperature environment that is 10° C. to 150° C. lower than the melting point of the polymer material that is the sample P and a low vacuum environment in the range of 10 ⁴ Pa to 10 ⁻¹ Pa. Then, it can be performed using the sample P placed in the environment. Specifically, the temperature controller 10 and the cooling device 9 are used to control the environmental temperature of the sample P, and the rotary pump 8 is operated to control the pressure in the chamber 6.

By performing the phase data acquisition step S30 using the sample P placed in the temperature environment as described above, it is possible to prevent the polymer material that is the sample P from melting and being unable to acquire the phase data. In addition, a temperature difference from the melting point of the polymer material can be secured, and the polymer material does not become sensitive to the crystallization point or glass transition point of the polymer material, making it easy to identify the target crosslinked structure.

Further, by performing the phase data acquisition step S30 using the sample P placed in the low vacuum environment as described above, the vibration amplitude of the cantilever 1 can be increased, and the measurement sensitivity of the phase data can be improved. it can. It should be noted that there is no problem in a low vacuum environment of up to 10 ⁻¹ Pa, but when the medium vacuum to high vacuum environment exceeding 10 ⁻² Pa is reached, the additive added to the polymer material is transferred to the surface of the sample P. It is difficult to move and identify the desired crosslinked structure. Therefore, the phase data acquisition step S30 is preferably performed in a low vacuum environment in the range of 10 ⁴ Pa to 10 ⁻¹ Pa.

FIG. 6 is a diagram showing an example of the phase data acquired in the phase data acquisition step S30. FIG. 6 shows a phase delay in the measurement area of the sample P having a length of 5 μm and a width of 10 μm by mapping in black and white shading. In FIG. 6, it is shown that the lighter and closer to white the part has a larger phase delay, and the darker and closer to the black part has a smaller phase delay.

(Histogram creation process)
In the cross-linking evaluation method S100 of the polymer material shown in FIG. 1, the histogram creating step S10 is performed using the phase data of the polymer material previously acquired by the same method as the above-described phase data acquiring step S30. Further, in the polymer material cross-linking evaluation method S100 shown in FIG. 4, the histogram creation step S10 is performed using the phase data of the polymer material acquired in the phase data acquisition step S30 described above. In the histogram creating step S10, a histogram is created using the phase data of the polymer material.

FIG. 7 is a diagram showing an example of the histogram created in the histogram creating step S10. In FIG. 7, the horizontal axis is the phase delay [deg], and the vertical axis is the intensity (frequency). The histogram shown in FIG. 7 is created based on the phase data acquired by performing the phase data acquisition step S30 in a state where the crosslinking of the polymer material as the sample is not completed. After the completion of the histogram creation step S10, a crosslinking evaluation step S20 is carried out as shown in FIGS.

(Crosslink evaluation process)
The cross-linking evaluation step S20 is a step of evaluating the cross-linked state of the polymer material, that is, the quality of the polymer material, based on the histogram created in the histogram creation step S10. More specifically, as shown in FIG. 7, the waveform represented by the histogram of the phase data can be separated into a plurality of waveforms, and the quality of the sample can be evaluated based on the information of the waveforms whose phases are delayed.

In the cross-linking evaluation step S20, a plurality of peaks P1, P2, P3 are identified in the waveform obtained from the histogram, and the phase delay and intensity at each peak P1, P2, P3 are extracted. For example, in the example shown in FIG. 7, the phase delays of the peaks P1, P2, and P3 of the waveform obtained from the histogram are θ1=−275 [deg], θ2=−248 [deg], and θ3=−238, respectively. [Deg], and the intensities are I1=100, I2=40, and I3=25, respectively.

In the waveform obtained from the histogram, the larger the number of waveforms, that is, the larger the number of identified peaks P1, P2, P3, the more uneven the cross-linking distribution. For example, such an analysis can be performed using the analysis PC 5 shown in FIG. Then, when the number of identified peaks P1, P2, P3 is plural, for example, as shown in FIG. 7, a monitor of the analysis PC 5 displays that the cross-linking distribution of the polymer material is non-uniform. You may

For example, in the waveform of the histogram shown in FIG. 7, among the waveforms corresponding to the plurality of peaks P1, P2, and P3, the larger the area of the waveform having the smaller phase delay, the more the polymer material has the hard portion, and the occurrence rate of the side reaction. Is high. For example, the analysis PC5 shown in FIG. 5 is used to perform such an analysis, and the fact that a side reaction occurs in the polymer material under analysis, the occurrence rate of the side reaction, etc. are shown in FIG. You may make it display on a monitor.

8 and 9 are diagrams showing an example of the phase data acquired in the phase data acquisition step S30. Similar to FIG. 6, FIGS. 8 and 9 show phase delays in black and white shading in the measurement area of the sample having a length of 5 μm and a width of 10 μm. The phase data shown in FIG. 9 represents the phase data acquired after a predetermined time has elapsed from the time when the phase data shown in FIG. 8 was acquired.

10 and 11 are diagrams showing histograms created in the histogram creating step S10 from the phase data shown in FIGS. 8 and 9, respectively. That is, the waveform of the histogram shown in FIG. 11 shows a state in which the waveform of the histogram shown in FIG. 10 has changed after the elapse of a predetermined time.

In the cross-linking evaluation step S20, the time when the peak of the waveform obtained from the histogram changes from plural to singular can be determined to be the end of cross-linking. Specifically, for example, when the plurality of peaks can be identified in the waveform of the histogram as shown in FIG. 10 and the state in which one peak can be identified in the waveform of the histogram as shown in FIG. It can be judged as time. In this case, similar to the example shown in FIG. 7, it is possible to display on the monitor of the analyzing PC 5 that the crosslinking has been completed.

In the bridge evaluation step S20, the phase delay at the maximum peak in the waveform of the histogram is compared at a predetermined time interval, and when the phase delay before the elapse of the predetermined time and the phase delay after the elapse of the predetermined time become equal. Can be determined to be the end of crosslinking. Specifically, first, as shown in FIG. 10, the maximum peak P0 is specified in the waveform of the histogram, and the phase delay θ0 of the peak P0 is extracted.

Next, as shown in FIG. 11, the maximum peak P1 is specified in the waveform of the histogram after a predetermined time has elapsed, the phase delay θ1 of the peak P1 is extracted, and the extracted phase delay θ1 and the predetermined time before the predetermined time elapses. The phase delay θ0 extracted in step 1 is compared. Then, when the inequality: |θ0|>|θ1| is satisfied, it is determined that the crosslinking is in progress, and when θ0=θ1, it is determined that the crosslinking is completed. Then, similar to the example shown in FIG. 7, for example, it is possible to display on the monitor of the analysis PC 5 that the crosslinking is in progress or that the crosslinking is completed.

In addition, in the cross-linking evaluation step S20, the time point when the half-value width Hn of the maximum peak of the waveform obtained from the histogram becomes 15 [deg] or less can be determined to be the end of cross-linking. The half-width Hn of the maximum peak may be determined to be 10±5 [deg] or less when the crosslinking is completed. Specifically, the half width Hn of the waveform having the maximum peak P1 is extracted from the histogram of the phase data shown in FIG.

When the half width Hn is larger than 10±5 [deg] (Hn>10±5 [deg]), it is determined that the crosslinking is in progress, and the half width Hn is 10±5 [deg] or less. If there is (Hn≦10±5 [deg]), it is determined that the crosslinking is completed. Then, similar to the example shown in FIG. 7, for example, it is possible to display on the monitor of the analysis PC 5 that the crosslinking is in progress or has been completed.

FIG. 12 is a flowchart showing a modified example of the method S100 for evaluating cross-linking of the polymer material shown in FIG. The crosslinking evaluation step S20 can include, for example, a waveform separation step S21 and a crosslinking degree determination step S22. The cross-linking evaluation step S20 shown in FIG. 4 can also include the same step as the cross-linking evaluation step S20 shown in FIG. Hereinafter, the waveform separation step S21 and the crosslinking degree determination step S22 included in the crosslinking evaluation step S20 in the modified example of the crosslinking evaluation method S100 of the polymer material shown in FIG. 12 will be described in detail.

(Wave separation process)
FIG. 13: is a figure which shows an example of the shape data of a polymer material. FIG. 14 is a diagram showing an example of phase data of a polymer material. Similar to FIG. 6, FIG. 14 shows the phase delay mapped in black and white shading in the measurement area of the sample having a length of 5 μm and a width of 10 μm. FIG. 15 is a diagram showing a histogram created in the histogram creating step S10 from the phase data shown in FIG.

The waveform separating step S21 is a step of separating a plurality of peak waveforms from the waveform of the histogram created in the histogram creating step S10. Specifically, paying attention to the shape of the peak of the waveform of the histogram of the phase data, the waveform of the histogram is separated into a plurality of waveforms corresponding to the plurality of peaks.

For example, in the waveform separating step S21, this waveform can be separated into three peak waveforms based on the two inflection points of the waveform obtained from the histogram. In other words, the waveform of the phase data histogram can be separated as a composite wave of three peak waveforms corresponding to the three peaks.

(Crosslinking degree determination process)
The crosslinking degree determining step S22 is a step of evaluating the crosslinking state based on the information of the peak waveform having the largest phase delay among the plurality of peak waveforms. Specifically, in the crosslinking degree determination step S22, the difference between the area of the peak waveform having the largest phase delay among the plurality of peak waveforms and the area of the original waveform before the waveform separation is obtained. Then, the ratio of this difference to the area of the original waveform before the waveform separation can be determined as the occurrence rate of the crosslinking reaction of the polymer material, that is, the degree of crosslinking [%].

In this case, the ratio of the area of the peak waveform having the largest phase delay among the plurality of peak waveforms to the area of the original waveform, that is, the peak area ratio S1 [%] may be obtained. Then, assuming that the area of the original waveform is 100%, the occurrence rate of the crosslinking reaction of the polymer material, that is, the degree of crosslinking [%] can be obtained from 100[%]-peak area ratio S1[%]. The peak area ratio S1 [%] and the degree of crosslinking [%] can be obtained, for example, by the analysis PC 5 shown in FIG. 5, and the obtained values are displayed on the monitor of the analysis PC 5, as shown in FIG. 15, for example. be able to.

In addition, in the crosslinking degree determination step S22, the ratio of the area of the peak waveform having the smallest phase delay among the plurality of peak waveforms to the area of the original waveform is determined by, for example, the rate of occurrence of a side reaction in which molecules of the polymer material are crosslinked [ %] can be determined.

Specifically, of the plurality of peak waveforms after the waveform separation, the ratio of the area of the peak waveform having the smallest phase delay to the area of the original waveform, that is, the peak area ratio S2 [%] is obtained. Then, the obtained peak area ratio S2 [%] is determined as the side reaction occurrence rate [%]. These can be obtained, for example, by the analysis PC 5 shown in FIG. 5, and the obtained values can be displayed on the monitor of the analysis PC 5, as shown in FIG. 15, for example.

In the waveform separating step S21, when this waveform is separated into three peak waveforms based on the two inflection points of the waveform obtained from the histogram, in the crosslinking degree determining step S22, the crosslinking degree and the side reaction are as follows. It is possible to obtain the occurrence rate of.

16 and 17 are diagrams showing an example of the threshold values θa and θb of the waveform obtained from the histogram. First, as shown in FIG. 16, of the two inflection points of the waveform obtained from the histogram, the inflection point with the larger phase delay is set as the threshold value θa, and the phase delay is greater than the threshold value θa. The ratio Sa [%] of the waveform area of the large portion is obtained.

In the example shown in FIG. 16, the phase delay threshold θa is −189 [deg], and the area ratio Sa of the waveform of the portion where the phase delay is larger than the threshold θa is 21.6 [%]. ]. The rate of occurrence of the crosslinking reaction, that is, the degree of crosslinking [%] can be calculated as 100−Sa=78.4[%]. These can be obtained by the analyzing PC 5 shown in FIG. 5, for example, and the obtained values can be displayed on the monitor of the analyzing PC 5 as shown in FIG. 16, for example.

Next, as shown in FIG. 17, of the two inflection points of the waveform obtained from the histogram, the inflection point with the smaller phase delay is set as the threshold value θb, and the phase that is greater than the threshold value θb. The ratio Sb of the waveform areas of the portion where the delay is small is calculated. In the example shown in FIG. 17, the phase delay threshold θb is −166 [deg], and the waveform area ratio Sb of the portion where the phase delay is smaller than the threshold θb is 15.1%. ]. The obtained area ratio Sb [%] can be determined as the side reaction occurrence rate [%]. These can be obtained, for example, by the analysis PC 5 shown in FIG. 5, and the obtained values can be displayed on the monitor of the analysis PC 5, as shown in FIG. 17, for example.

FIG. 18 is a diagram showing phase data having a larger phase delay than the threshold value θa shown in FIG. FIG. 19 is a diagram showing phase data having a smaller phase delay than the threshold value θb shown in FIG. In the phase data shown in FIG. 18, black and white shading is a light color close to white as a whole, whereas in the phase data shown in FIG. 19, black and white shading is a color close to black as a whole. That is, it is indicated that the polymer material is softer in the portion where the phase delay is larger than the phase delay threshold θa in the histogram than in the portion where the phase delay is smaller than the phase delay threshold θb.

As described above, the cross-linking evaluation method S100 of the polymer material of the present embodiment is a method of evaluating the cross-linking state of the polymer material, and includes a histogram creation step S10 of creating a histogram from phase data of the polymer material, and a histogram creation step S10. And a cross-linking evaluation step S20 for evaluating the cross-linked state of the polymer material based on the above.

Thereby, a histogram can be created from the phase data of the polymer material, and the cross-linking distribution of the polymer material can be directly observed. Furthermore, by evaluating the cross-linking state of the polymer material based on the histogram, for example, in the polymer material in which the cross-linking reaction proceeds slowly, it is possible to determine the completion time of cross-linking, the uniformity of cross-linking distribution, and the molecules of the polymer material The occurrence of side reactions such as crosslinking can be evaluated.

In addition, in the cross-linking evaluation method S100 of the polymer material of the present embodiment, the cross-linking evaluation step S20 can include a waveform separation step S21 that separates a plurality of peak waveforms from the waveform obtained from the histogram. Further, the crosslinking evaluation step S20 may include a crosslinking degree determination step S22 that evaluates the crosslinking state based on the information of the peak waveform having the largest phase delay among the plurality of peak waveforms.

Therefore, it is necessary to identify the incidence of cross-linking and the incidence of side reactions from the waveform of a complex-shaped histogram that has multiple peaks from the initial stage when the cross-linking reaction is not proceeding to the completion of the cross-linking reaction Information can be obtained.

Further, in the polymer material crosslinking evaluation method S100 of the present embodiment, in the waveform separating step S21, the waveform can be separated into three peak waveforms based on the two inflection points of the waveform obtained from the histogram. Then, in the crosslinking degree determining step S22, the difference between the area of the peak waveform having the largest phase delay among the three peak waveforms and the area of the waveform is obtained, and the ratio of the difference to the area of the waveform is determined by crosslinking the polymer material. It can be determined as the incidence of reaction. This facilitates identifying the rate of cross-linking and side reactions of the polymeric material.

Further, in the cross-linking evaluation method S100 of the present embodiment, in the cross-linking degree determining step S22, the ratio of the area of the peak waveform having the smallest phase delay among the three peak waveforms to the area of the waveform is defined as the molecular weight of the polymer material. It can be determined as the rate of occurrence of a side reaction in which the two crosslink each other. This facilitates the identification of the side reaction occurrence rate of the polymer material.

Further, in the cross-linking evaluation method S100 of the present embodiment, in the cross-linking evaluation step S20, the time when the peak of the waveform obtained from the histogram changes from plural to singular can be determined to be the end of cross-linking. This makes it easy to identify when the crosslinking of the polymeric material has ended.

Further, in the cross-linking evaluation method S100 of the present embodiment, in the cross-linking evaluation step S20, it is determined that the half-width of the maximum peak of the waveform obtained from the histogram is 15 [deg] or less as the end of cross-linking. You can This makes it easy to identify when the crosslinking of the polymeric material has ended.

In addition, the polymer material crosslinking evaluation method S100 of the present embodiment may include a phase data acquisition step S30 that acquires phase data in the phase mode of the atomic force microscope before the histogram creation step S10. Thereby, even if the phase data of the polymer material cannot be obtained in advance, the phase data of the polymer material can be acquired by the phase data acquisition step S30.

In addition, in the cross-linking evaluation method S100 of the polymer material of the present embodiment, the phase data acquisition step S30 is performed in a temperature environment of 10° C. to 150° C. lower than the melting point of the polymer material and in the range of 10 ⁴ Pa to 10 ⁻¹ Pa. It can be done with a polymeric material placed in a vacuum environment. This can improve the measurement sensitivity of the phase data, prevent the additive added to the polymer material from moving to the sample surface, and make it easy to identify the target crosslinked structure.

The polymer material evaluated by the polymer material crosslinking evaluation method S100 of the present embodiment is preferably a moisture-curable polymer material in which a silane coupling agent is introduced into the polymer structure. Since the moisture-curable polymer material may cause a defect such as a poor appearance when a side reaction occurs, the evaluation by the polymer material crosslinking evaluation method S100 of the present embodiment is particularly effective.

The embodiment of the present invention has been described in detail above with reference to the drawings, but the specific configuration is not limited to this embodiment, and there are design changes and the like within the scope not departing from the gist of the present invention. However, they are included in the present invention.

(Example)
First, 0.5 part by weight of dicumyl peroxide, 4 parts by weight of vinyltrimethoxysilane, 100 parts by weight of chlorinated polyethylene, 10 parts by weight of epoxidized soybean oil, and 1 part by weight of dibutyltin dilaurate were weighed. Then, dicumyl peroxide and vinyltrimethoxysilane were removed, and these were compounded, and the compounding agent was kneaded for 15 minutes with a rubber roll having a diameter of 150 mm set to a temperature of 120 to 130° C. to form a sheet.

Next, the formed sheet is crushed by a crusher at room temperature, impregnated with dicumyl peroxide and vinyltrimethoxysilane in a closed system at a temperature of 60° C., the head is 180° C., and the first cylinder is 180° C. The second cylinder was set to 130° C., and the graft reaction was performed using a 40 m/m extruder (L/D=22) in which the screw rotation speed was set to 10 rpm.

Next, a cable was produced by forming the outer layer by coating the above silane crosslinked chlorinated polyethylene around the four core wires obtained by coating the cable conductor with the crosslinked polyethylene. The extrusion conditions were 150° C. for the head, 150° C. for the first cylinder, and 130° C. for the second cylinder, and the screw rotation speed was 20 rpm. Then, the cable was wound with a winder and left at room temperature for 2 weeks to spontaneously crosslink. Further, the outer layer coating was sampled at regular intervals to observe the occurrence of crosslinking.

A part of the outer layer coating of the produced cable was cut into a size of 5 mm×5 mm×1 mm using a razor, and this was fixed to a sample stand of an atomic force microscope. As the probe microscope, an E-sweep/Nano Navi station manufactured by SII Nano Technology Co., Ltd. was used. This device mainly has the following configuration. Environmental control chamber for measuring the sample under a constant environment, temperature controller for controlling the temperature in the chamber, rotary pump for vacuum control in the chamber, scanner for three-dimensionally moving the sample minutely, data captured It is a control personal computer for image processing.

The environmental control chamber is placed on the vibration isolation table and is housed in a shield box to remove electric noise from the surroundings. As the scanner, a wide scanner capable of scanning up to 150 μm×150 μm was used. As the cantilever, SI-DF20 (SII Nano Technology Co., Ltd.) made of Si having a spring constant of 15/m and a resonance frequency of 150 kHz was used.

A Cu plate having high thermal conductivity was used for the sample table in the chamber, and the sample was fixed using Ag paste for high temperature. The melting point of the outer layer portion of the produced cable was measured in advance by DSC (Differential Scanning Calorimetry), and was 100°C to 130°C. Therefore, the temperature of the temperature controller was set to a temperature 80° C. lower than 130° C., that is, 50° C., and the sample was allowed to stand for a certain time until the sample temperature reached 50° C. Further, in order to bring the inside of the chamber containing the sample into a low vacuum state, a vacuum was drawn using a rotary pump. Dynamic Force Mode (DFM) was used for the measurement of the shape and the phase.

Thereafter, the outer layer coating of the cable was evaluated by the cross-linking evaluation method of the polymer material described in the above embodiment. As a result, it was possible to directly observe the cross-linking distribution of the silane-crosslinked chlorinated polyethylene by creating a histogram from the phase data of the silane-crosslinked chlorinated polyethylene. Furthermore, by evaluating the cross-linking state of the silane-crosslinked chlorinated polyethylene based on the histogram, in the silane-crosslinked chlorinated polyethylene in which the crosslinking reaction proceeds slowly, determination of the completion time of crosslinking, uniformity of cross-linking distribution, and silane It was possible to evaluate the occurrence of a side reaction in which the molecules of the crosslinked chlorinated polyethylene were crosslinked with each other.

S10 Histogram creating step S20 Crosslinking evaluation step S21 Waveform separation step S22 Crosslinking degree determination step S30 Phase data acquisition step S100 Crosslinking evaluation method

Claims (10)

A cross-linking evaluation method for evaluating the cross-linking state of a polymer material,
A histogram creation step of creating a histogram from the phase data of the polymer material,
Have a, a crosslinking evaluation step of evaluating the crosslinked state of the polymer material based on said histogram,
The crosslinking evaluation step,
A waveform separation step of separating a plurality of peak waveforms from the waveform obtained from the histogram,
Most phase bridge evaluation method of a polymer material characterized by a delay based on the information of the large peak waveform to have a, a crosslinking degree determination step of evaluating the crosslinked state of the plurality of peak waveform. In the waveform separation step, the waveform is separated into three peak waveforms based on the two inflection points of the waveform obtained from the histogram,
In the step of determining the degree of crosslinking, the difference between the area of the peak waveform having the largest phase delay among the three peak waveforms and the area of the waveform is obtained, and the ratio of the difference to the area of the waveform is determined by crosslinking the polymer material. The method for evaluating cross-linking of a polymer material according to claim 1 , wherein the rate of occurrence of reaction is determined. In the step of determining the degree of cross-linking, determining the ratio of the area of the peak waveform having the smallest phase delay among the three peak waveforms to the area of the waveform as the incidence of a side reaction in which molecules of the polymer material cross-link. The cross-linking evaluation method for a polymer material according to claim 2 . The polymer according to any one of claims 1 to 3 , wherein in the crosslinking evaluation step, a time point at which the peak of the waveform obtained from the histogram changes from a plurality to a single number is determined to be the end time of the crosslinking. Evaluation method for cross-linking of materials. In the crosslinking evaluation step, any one of claims 1 to 3 in which the half-value width of the maximum peak of the waveform obtained from the histogram and judging a 15 [deg] when the time crosslinking termination becomes less The method for evaluating cross-linking of a polymer material according to the item 1. A cross-linking evaluation method for evaluating the cross-linking state of a polymer material,
A histogram creation step of creating a histogram from the phase data of the polymer material,
A cross-linking evaluation step of evaluating the cross-linked state of the polymer material based on the histogram,
In the cross-linking evaluation step, the cross-linking evaluation method for a polymer material is characterized in that the time point at which the peak of the waveform obtained from the histogram changes from plural to singular is judged to be the end time of cross-linking. A cross-linking evaluation method for evaluating the cross-linking state of a polymer material,
A histogram creation step of creating a histogram from the phase data of the polymer material,
A cross-linking evaluation step of evaluating the cross-linked state of the polymer material based on the histogram,
In the cross-linking evaluation step, the cross-linking evaluation method for a polymer material is characterized in that the time point when the half-value width of the maximum peak of the waveform obtained from the histogram becomes 15 [deg] or less is determined as the end time of cross-linking. Before the histogram creation step, polymeric material as claimed in any one of claims 1 to 7, characterized in that it comprises a phase data obtaining step of obtaining the phase data by a phase mode of an atomic force microscope Cross-linking evaluation method. The phase data acquisition step is performed using the polymer material placed in a low-vacuum environment in the range of 10 ⁴ Pa to 10 ⁻¹ Pa in a temperature environment 10° C. to 150° C. lower than the melting point of the polymer material. 9. The method for evaluating cross-linking of a polymer material according to claim 8 . The method for crosslinking evaluation of a polymer material according to any one of claims 1 to 9 , wherein the polymer material is a moisture-curable polymer material in which a silane coupling agent is introduced in a polymer structure. ..

Images