Evaluation method of curing degree of thermosetting resin

Abstract

A method for evaluating the degree of curing of a thermosetting resin, which is a method for evaluating the degree of curing of a thermosetting resin obtained by a dehydration polycondensation reaction, comprising: a step of preparing a sample containing the thermosetting resin; a step of maintaining the sample at a predetermined first temperature for a predetermined holding time to remove adsorbed water in the sample; a step of heating the sample after the step of removing the adsorbed water from the first temperature to a second temperature lower than the decomposition temperature of the thermosetting resin to generate desorbed water; a step of calculating the mass of the generated desorbed water; and a step of evaluating the degree of curing of the thermosetting resin based on the mass of the thermosetting resin contained in the sample after the step of generating the desorbed water and the calculated mass of the desorbed water.

Description

Technical Field

[0001] The present disclosure relates to a method for evaluating the degree of curing of a thermosetting resin. This application claims priority based on Japanese Patent Application No. 2019-236551 filed on December 26, 2019. All the contents described in the Japanese patent application are incorporated herein by reference. Background Art

[0002] Resins (e.g., thermosetting resins) having excellent chemical resistance and electrical insulation properties can be used as insulators, coating agents, and adhesives for various electronic components. For example, aromatic polyimides, which are thermosetting resins, have a conjugated structure between aromatic rings via an imide bond, and thus have a rigid and strong molecular structure. In addition, it is known that the imide bond has a strong intermolecular force, so the aromatic polyimide has high thermal performance, high mechanical properties, and high chemical properties. Such aromatic polyimides can be used, for example, as insulating materials and heat-resistant materials for circuits.

[0003] Prior art literature

[0004] Non-patent literature

[0005] Non-patent document 1: "New Edition of Handbook of Polymer Analysis" compiled by the Japan Society of Analytical Chemistry, Kinokuniya Bookstore, January 1995, page 1310 Summary of the invention

[0006] The method for evaluating the curing degree of a thermosetting resin disclosed in the present invention is a method for evaluating the curing degree of a thermosetting resin obtained by a dehydration polycondensation reaction, and includes:

[0007] A step of preparing a sample containing the above-mentioned thermosetting resin;

[0008] The step of maintaining the sample at a predetermined first temperature for a predetermined holding time to remove adsorbed water in the sample;

[0009] The step of heating the sample after the step of removing the adsorbed water from the first temperature to a second temperature lower than the decomposition temperature of the thermosetting resin to generate desorbed water;

[0010] The step of calculating the mass of the generated separated water; and

[0011] A step of evaluating the degree of curing of the thermosetting resin based on the mass of the thermosetting resin contained in the sample after the step of generating the desorbed water and the calculated mass of the desorbed water. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] [ Figure 1 ] Figure 1This is a graph showing a variation pattern of the heating temperature with the passage of time in the temperature-raising heating generated gas analysis of the embodiment and the amount of water generated with the passage of time.

[0013] [ Figure 2 ] Figure 2 This is a spectrum chart obtained when a plurality of samples having different degrees of curing were analyzed by infrared spectroscopy, which is a conventional method. DETAILED DESCRIPTION

[0014] [Problems to be Solved by the Present Disclosure]

[0015] Thermosetting resins such as aromatic polyimide have a higher degree of curing as the polymerization reaction proceeds, so their physical properties change significantly. Therefore, from the perspective of managing the quality of thermosetting resins, a method for evaluating the degree of curing of thermosetting resins has been proposed.

[0016] For example, the "New Edition of the Handbook of Polymer Analysis" compiled by the Japan Society for Analytical Chemistry, Kinokuniya Bookstore, January 1995, page 1310 (Non-Patent Document 1) discloses the use of infrared spectroscopy or nuclear magnetic resonance spectroscopy to analyze the chemical structure of aromatic polyimides, and based on the analysis results, evaluate the degree of curing (imidization rate) of the above aromatic polyimides.

[0017] However, the evaluation method disclosed in Non-Patent Document 1 has insufficient sensitivity, and thus further improvement is required.

[0018] The present disclosure has been made in view of the above circumstances, and an object of the present disclosure is to provide a method for evaluating the degree of curing of a thermosetting resin with excellent sensitivity.

[0019] [Effects of the present disclosure]

[0020] According to the present disclosure, a method for evaluating the degree of curing of a thermosetting resin having excellent sensitivity can be provided.

[0021] [Description of Embodiments of the Present Disclosure]

[0022] First, embodiments of the present disclosure are listed and described.

[0023] [1] A method for evaluating the degree of cure of a thermosetting resin according to one embodiment of the present disclosure is a method for evaluating the degree of cure of a thermosetting resin obtained by a dehydration polycondensation reaction, comprising:

[0024] A step of preparing a sample containing the above-mentioned thermosetting resin;

[0025] The step of maintaining the sample at a predetermined first temperature for a predetermined holding time to remove adsorbed water in the sample;

[0026] The step of heating the sample after the step of removing the adsorbed water from the first temperature to a second temperature lower than the decomposition temperature of the thermosetting resin to generate desorbed water;

[0027] The step of calculating the mass of the generated separated water; and

[0028] A step of evaluating the degree of curing of the thermosetting resin based on the mass of the thermosetting resin contained in the sample after the step of generating the desorbed water and the calculated mass of the desorbed water.

[0029] In the evaluation method of the degree of curing of the above-mentioned thermosetting resin, the thermosetting resin from which adsorbed water has been removed is heated to a second temperature to be heated again, thereby performing a dehydration condensation reaction in the unreacted repeating unit and generating dehydrated water. The mass of the generated dehydrated water is related to the number of the above-mentioned unreacted repeating units. On the other hand, it is believed that the above-mentioned thermosetting resin contained in the above-mentioned sample after the step of generating the above-mentioned dehydrated water has completed the above-mentioned dehydration condensation reaction in all repeating units, so the total number of repeating units constituting the thermosetting resin can be estimated from the mass of the thermosetting resin. Therefore, based on the mass of the above-mentioned thermosetting resin contained in the above-mentioned sample after the step of generating the above-mentioned dehydrated water and the mass of the dehydrated water, the degree of curing of the above-mentioned thermosetting resin can be evaluated. This evaluation method obtains the degree of curing of the above-mentioned thermosetting resin based on the mass of the above-mentioned dehydrated water, etc., so compared with the conventional evaluation method using infrared spectroscopy, the sensitivity is improved. That is, according to the present disclosure, a method for evaluating the degree of curing of a thermosetting resin with excellent sensitivity can be provided.

[0030] [2] The first temperature is preferably 50° C. to 100° C. By setting the first temperature in this manner, the method for evaluating the degree of curing of the thermosetting resin can more appropriately remove adsorbed water and has excellent accuracy.

[0031] [3] The holding time is preferably more than 30 minutes and less than 120 minutes. By defining the holding time in this way, the method for evaluating the degree of curing of the thermosetting resin can more appropriately remove adsorbed water and has excellent accuracy.

[0032] [4] Preferably, the step of generating desorbed water includes heating from the first temperature to the second temperature at a heating rate of 50°C / min or less. By specifying this, the method for evaluating the degree of curing of the thermosetting resin has excellent accuracy.

[0033] [5] The second temperature is preferably higher than 100° C. and lower than 400° C. By setting the second temperature in this manner, the method for evaluating the degree of curing of the thermosetting resin can more appropriately generate desorbed water and has excellent accuracy.

[0034] [6] The thermosetting resin is preferably at least one selected from the group consisting of polyimide resins, phenolic resins, and amino resins. The method for evaluating the degree of curing of the thermosetting resin is particularly suitable for the evaluation method of the thermosetting resins listed above.

[0035] [Details of the embodiments of the present disclosure]

[0036] An embodiment of the present disclosure (hereinafter referred to as "this embodiment") is described below. However, this embodiment is not limited to this. In this specification, the expression in the form of "A to Z" refers to the upper and lower limits of the range (i.e., above A and below Z). When there is no unit recorded for A and only the unit recorded for Z, the unit of A is the same as the unit of Z. In this specification, "repeating unit" refers to the smallest repeating unit constituting the above-mentioned thermosetting resin. The concept of the above-mentioned repeating unit also includes the repeating units in which the above-mentioned dehydration condensation reaction is completed, and also includes the repeating units in which the dehydration condensation reaction is in the middle stage. The repeating unit in which the dehydration condensation reaction is in the middle stage is sometimes specifically referred to as an "unreacted repeating unit".

[0037] 《Evaluation method of curing degree of thermosetting resin》

[0038] A method for evaluating the degree of cure of a thermosetting resin according to one embodiment of the present disclosure is a method for evaluating the degree of cure of a thermosetting resin obtained by a dehydration polycondensation reaction, comprising:

[0039] A step of preparing a sample containing the above-mentioned thermosetting resin;

[0040] The step of maintaining the sample at a predetermined first temperature for a predetermined holding time to remove adsorbed water in the sample;

[0041] The step of heating the sample after the step of removing the adsorbed water from the first temperature to a second temperature lower than the decomposition temperature of the thermosetting resin to generate desorbed water;

[0042] The step of calculating the mass of the generated separated water; and

[0043] A step of evaluating the degree of curing of the thermosetting resin based on the mass of the thermosetting resin contained in the sample after the step of generating the desorbed water and the calculated mass of the desorbed water.

[0044] The method for evaluating the degree of curing of the thermosetting resin is a method for evaluating the degree of curing of the thermosetting resin obtained by a dehydration polycondensation reaction. Here, "a thermosetting resin obtained by a dehydration polycondensation reaction" refers to a thermosetting resin generated by a plurality of monomer compounds as raw materials of the thermosetting resin being linked together by forming new bonds while removing water molecules from each other's molecules.

[0045] Examples of the thermosetting resin obtained by dehydration polycondensation reaction include polyimide resins, phenolic resins, and amino resins. That is, the thermosetting resin is preferably at least one selected from the group consisting of polyimide resins, phenolic resins, and amino resins.

[0046] Examples of the polyimide resin include aromatic polyimide, aliphatic polyimide, etc. Examples of the phenolic resin include novolac, etc. Examples of the amino resin include urea-formaldehyde resin, etc. Each step is described below.

[0047] <Step of Preparing a Sample Containing a Thermosetting Resin>

[0048] In this step, a sample containing the above-mentioned thermosetting resin is prepared. The above-mentioned sample may be composed of the above-mentioned thermosetting resin, or may be composed of the above-mentioned thermosetting resin and a substance other than the above-mentioned thermosetting resin. As a sample corresponding to the latter, for example, a sample composed of a copper foil and a polyimide resin film formed on the above-mentioned copper foil can be cited. The sample corresponding to the latter can be set as a sample composed of the above-mentioned thermosetting resin by removing substances other than the above-mentioned thermosetting resin in advance. The shape of the thermosetting resin contained in the above-mentioned sample is not particularly limited, but it is preferably in the form of a film or a powder. In the case where the shape of the above-mentioned thermosetting resin is a film, its thickness is preferably not less than 50μm and not more than 100μm. By setting the thermosetting resin in a film or powder form, it tends to be possible to effectively remove the adsorbed water described later, and to effectively generate the desorbed water described later.

[0049] Examples of the substance other than the thermosetting resin contained in the sample include metals such as copper and silver, resins that do not generate dehydrated water by heating, and inorganic fillers.

[0050] The mass of the thermosetting resin contained in the sample is not particularly limited, but is, for example, preferably from 1 mg to 1000 mg, and more preferably from 10 mg to 100 mg.

[0051] <Step of Removing Adsorbed Water in Sample>

[0052] In this step, the sample is kept at a predetermined first temperature for a predetermined holding time to remove adsorbed water in the sample. Here, "adsorbed water" refers to water attached to the surface of the sample and is water that can be removed from the sample by vaporization.

[0053] As the first temperature, for example, it is preferably below the temperature at which the thermosetting resin starts to undergo a dehydration condensation reaction, and more preferably above the boiling point of water and below the temperature at which the thermosetting resin starts to undergo a dehydration condensation reaction. In this way, adsorbed water is more appropriately removed, and on the other hand, the generation of desorbed water described later is suppressed. Therefore, the accuracy of the evaluation method for the degree of curing of the thermosetting resin is excellent. Under atmospheric pressure (e.g., 1013.25 hPa), when adsorbed water is removed from the sample, the first temperature is preferably above 50°C and below 100°C.

[0054] The holding time is not particularly limited as long as it is a time that can sufficiently remove the adsorbed water and suppress the dehydration condensation reaction of the thermosetting resin. In the present embodiment, the holding time is preferably more than 30 minutes and less than 120 minutes, and more preferably more than 60 minutes and less than 90 minutes.

[0055] As a device for removing the above-mentioned adsorbed water from the above-mentioned sample, as long as it has a heating unit for heating the above-mentioned sample and a detection unit for detecting the above-mentioned adsorbed water and the desorbed water described later, it is not particularly limited. As such a device, for example, a TPD-MS device (formal name: heating to generate gas mass analysis device), a TG-MS device (formal name: thermal gravimetric mass analysis device), and an EGA-MS device (formal name: generating gas mass analysis device) can be listed. More specifically, the heating to generate gas analysis device described in the embodiments described later can be listed. The above-mentioned heating to generate gas analysis device is equipped with a heating unit (manufactured by NETZSCH, trade name: STA449 F5 Jupiter) and a mass analysis unit (manufactured by JEOL Ltd., trade name: JMS-Q1500GC). In this case, the mass analysis unit corresponds to the above-mentioned detection unit.

[0056] <Steps to generate detached water>

[0057] In this step, the sample after the step of removing the adsorbed water is heated from the first temperature to a second temperature lower than the decomposition temperature of the thermosetting resin to generate desorbed water. In this embodiment, the heating temperature is distinguished by the first temperature and the second temperature. Therefore, the adsorbed water is detected when heated at the first temperature, and the desorbed water is detected when heated at the second temperature. That is, adsorbed water and desorbed water are distinguished and detected corresponding to the above-mentioned heating temperature. Here, "desorbed water" refers to water molecules generated by removing from unreacted repeating units through a dehydration condensation reaction. For example, in the case where the thermosetting resin is an aromatic polyimide, the unreacted repeating units in the thermosetting resin are heated from the first temperature to the second temperature, thereby performing a dehydration condensation reaction shown by the following reaction formula, and generating 1 water molecule per 1 repeating unit.

[0058] [Chemical formula 1]

[0059]

[0060] In the step of generating the desorbed water, the temperature is preferably raised from the first temperature to the second temperature at a rate of 50°C / min or less, and more preferably raised from the first temperature to the second temperature at a rate of 10°C / min to 20°C / min. Thus, the accuracy of the evaluation method of the degree of curing of the thermosetting resin is excellent.

[0061] The second temperature is not particularly limited as long as it is above the temperature at which the thermosetting resin starts to undergo a dehydration condensation reaction and below the decomposition temperature of the thermosetting resin, and is, for example, preferably above 100° C. and below 400° C. In one aspect of the present embodiment, the second temperature is further preferably above 200° C. and below 400° C.

[0062] The device for generating the desorbed water is not particularly limited, and examples thereof include the above-mentioned heating-generated gas analysis device.

[0063] <Steps for calculating the mass of generated desorbed water>

[0064] In this step, the mass of the generated desorbed water is calculated. The method for calculating the mass of the desorbed water is not particularly limited, but for example, a method of calculating using the software (trade name: Escrime (trademark)) provided in the mass analysis unit of the heated gas analysis device (manufactured by JEOL Ltd., trade name: JMS-Q1500GC) can be cited. Specifically, first, a graph showing the amount of water generated over time is prepared (for example, Figure 1 ). Next, the area of ​​the time range in which the desorbed water is considered to be generated in the above curve graph is obtained. The mass of the desorbed water is calculated based on the obtained area. It should be noted that in this embodiment, the amount of water detected when the temperature is raised from the first temperature is set to zero point as the baseline for obtaining the above area.

[0065] <Step for evaluating the degree of curing of the thermosetting resin>

[0066] In this step, the curing degree of the thermosetting resin is evaluated based on the mass of the thermosetting resin contained in the sample after the step of generating the dewatered water and the mass of the dewatered water calculated. The mass of the dewatered water generated is related to the number of unreacted repeating units in the thermosetting resin before the step of generating the dewatered water. On the other hand, it is considered that the thermosetting resin contained in the sample after the step of generating the dewatered water completes the dehydration condensation reaction in all repeating units, and the total number of repeating units constituting the thermosetting resin can be estimated based on the mass of the thermosetting resin. Therefore, the curing degree of the thermosetting resin can be evaluated based on the mass of the thermosetting resin contained in the sample after the step of generating the dewatered water and the mass of the dewatered water. This evaluation method calculates the curing degree of the thermosetting resin based on the mass of the dewatered water, etc., so the sensitivity is improved compared with the conventional evaluation method using infrared spectroscopy. That is, according to the present disclosure, a method for evaluating the curing degree of a thermosetting resin with excellent sensitivity can be provided.

[0067] For example, when the thermosetting resin is an aromatic polyimide shown in the above reaction formula, and the presence of the amic acid and the unreacted monomer compound is considered to be negligible, one unreacted repeating unit generates one molecule of water. Therefore, the number of molecules of desorbed water is equivalent to the number of unreacted repeating units in the thermosetting resin before the step of generating the desorbed water. Taking this into account, the degree of curing of the thermosetting resin can be calculated by the following formula. In the following formula, (W w / M w ) corresponds to the number of unreacted repeating units in the above-mentioned thermosetting resin before the step of generating the above-mentioned dehydration step.

[0068] Degree of solidification (%)=100×[1-{(W w / M w )×M p} / W p 〕

[0069] W p : The mass of thermosetting resin contained in the sample after the step of generating and removing water

[0070] M p : Molecular weight of the repeating unit of the thermosetting resin

[0071] W w : Calculated mass of separated water

[0072] M w : The molecular weight of water (i.e. 18)

[0073] The above is a description of the evaluation method of the degree of curing of the thermosetting resin involved in the present embodiment, but it is not limited to this. For example, in the step of generating the above-mentioned desorbed water, when two molecules of water molecules are generated for one unreacted repeating unit as the above-mentioned desorbed water, it is considered that the number of unreacted repeating units contained in the above-mentioned thermosetting resin is half the number of molecules of the above-mentioned desorbed water. In this case, the formula for calculating the above-mentioned degree of curing is deformed as follows.

[0074] Degree of solidification (%)=100×[1-{(W w / M w ) / 2×M p} / W p 〕

[0075] Example

[0076] The present disclosure will be described in more detail below with reference to examples, but the present disclosure is not limited thereto.

[0077] <Sample Preparation>

[0078] A sample composed of a polyimide resin as a thermosetting resin was prepared in the following order. First, a varnish (trade name: Pyre-ML) manufactured by IS,T Co., Ltd. was applied on a glass plate with a size of 100 mm × 100 mm and a thickness of 50 μm. The glass plate coated with the varnish was placed in a heating furnace and heated at a heating temperature of 400°C to cure. The heating time at this time can be any one of 30 seconds, 40 seconds and 50 seconds. In this way, three samples with different degrees of curing of the resin were prepared (mass of the resin: 500 mg).

[0079] <Analysis of Samples Using Heated Gas Analyzer and Discussion of Analysis Conditions>

[0080] The above-mentioned sample is analyzed using a heated gas analyzer in the following order. Specifically, the above-mentioned sample (the sample with a heating time of 30 seconds) is placed in the heating part of the heated gas analyzer, and is maintained at atmospheric pressure (1013.25 hPa) and 100°C (first temperature) for 30 minutes (T1), 60 minutes (T2), 90 minutes (T3) or 120 minutes (T4) (holding time), and the amount of water detected during the period is measured (a step of removing adsorbed water in the sample). After the above-mentioned holding time, the temperature is increased to 400°C at a heating rate of 20°C / min, and the amount of water detected during the period is measured (a step of generating desorbed water). The structure of the heated gas analyzer is as follows.

[0081] Heating unit: Made by NETZSCH, Trade name: STA449 F5 Jupiter

[0082] Quality Analysis Department: Made by JEOL Ltd., Trade Name: JMS-Q1500GC

[0083] (Discussion of the procedure for removing adsorbed water from a sample)

[0084] The above measurement results are shown in Figure 1 . Figure 1 The horizontal axis represents the elapsed time from the start of analysis. Figure 1 The vertical axis represents the temperature in the analysis device (the right vertical axis) and the amount of water (the left vertical axis) at each elapsed time. Figure 1 The curves C1 to C4 in the graph represent the amount of water detected when heating is performed in the temperature variation patterns T1 to T4, respectively. It is considered that the water measured at the first temperature comes from the adsorbed water adsorbed on the surface of the sample. Figure 1 The results show that the amount of water reaches a stable period (C2 to C4) after the first temperature is maintained for 60 minutes. That is, it is believed that all the water adsorbed on the sample is removed by maintaining the first temperature for more than 60 minutes.

[0085] (Evaluation of the degree of curing of thermosetting resin)

[0086] Next, find Figure 1 The moisture content is calculated by taking the area in the range of heating temperature of 100°C to 400°C in each curve of C1 to C4 (the step of calculating the mass of desorbed water). The moisture content is calculated using the software (trade name: Escrime (trademark)) attached to the JMS-Q1500GC. In addition, the mass of the thermosetting resin contained in the above-mentioned sample after the step of generating desorbed water is measured using an electronic balance. Finally, the calculated mass of desorbed water is divided by the mass of the above-mentioned thermosetting resin to calculate the moisture content per unit mass of the thermosetting resin. The results are shown in Table 1. In Table 1, Test No. 1 corresponds to the comparative example, and Test Nos. 2 to 4 correspond to the embodiments.

[0087] [Table 1]

[0088]

[0089] In Test No. 2 to 4, where the retention time was 60 minutes or more, the water content per unit mass of the thermosetting resin was 1.05 μg / mg, whereas in Test No. 1, where the retention time was 30 minutes, the water content was 0.8 μg / mg. In Test No. 1, such a result was probably obtained because the adsorbed water could not be fully removed, and a higher position than the original was used as the baseline.

[0090] From the above results, it is understood that when removing adsorbed water at 100° C. under atmospheric pressure, the retention time is preferably longer than 30 minutes, and more preferably longer than 60 minutes.

[0091] <Evaluation of Thermosetting Resins with Different Degrees of Curing>

[0092] The samples prepared in the above-mentioned <Preparation of Samples> (three samples with different degrees of cure) are used to evaluate the degree of cure of the thermosetting resin. Specifically, the above-mentioned samples are arranged in the heating part of the heating gas analysis device, and are kept at atmospheric pressure and 100°C (first temperature) for 60 minutes (holding time), and the amount of water detected during the period is measured (a step of removing adsorbed water in the sample). After the above-mentioned holding time, the temperature is increased to 400°C at a heating rate of 20°C / min, and the amount of water detected during the period is measured (a step of generating desorbed water). Based on the obtained experimental data, a graph is prepared to show the relationship between the time elapsed from the start of the analysis and the amount of water detected. Based on the prepared graph, the amount of moisture in the range of heating temperature of 100°C to 400°C is calculated (a step of calculating the mass of the desorbed water generated). In addition, an electronic balance is used to measure the mass of the above-mentioned thermosetting resin contained in the above-mentioned sample after the step of generating desorbed water. Finally, the degree of cure of each sample is calculated based on the above-mentioned calculation formula (a step of evaluating the degree of cure of the thermosetting resin). At this time, M p Set to 400, M w The calculation is performed by setting 18. It should be noted that most of the polyimides contained in the three samples prepared have a repeating unit structure that completely forms an imide ring. Taking these points into consideration, it is believed that the unreacted repeating unit is imidized according to the above reaction formula. In addition, the presence of amic acid and unreacted monomer compounds is considered to be a negligible trace amount, so it is not considered. The results are shown in Table 2.

[0093] [Table 2]

[0094]

[0095] * The mass of polyimide contained in the sample after the step of generating dewater

[0096] From the results in Table 2, it can be seen that the above evaluation method can evaluate the degree of curing of the thermosetting resin with a sensitivity of about 0.5%.

[0097] <Comparative Discussion with Conventional Methods>

[0098] For the purpose of comparative experiment, the curing degree of the samples (three types of samples having different curing degrees) prepared in the above-mentioned <Preparation of Samples> was evaluated by a conventional evaluation method using infrared spectroscopy. Figure 2The infrared spectra of samples prepared with different heating times are shown. Figure 2 In the above figure, the horizontal axis represents the wave number and the vertical axis represents the absorption intensity. In the evaluation method using infrared spectroscopy, based on the 1770 cm-1 wavelength derived from the cyclic imide -1 The peak intensity of 1500 cm-1 derived from the skeleton vibration of benzene -1 The peak intensity of Figure 2 It can be clearly seen that the intensity of the two peaks shows almost the same value between each sample. That is, it is difficult to distinguish the degree of cure of these samples by conventional methods (see Table 2). In other words, it can be seen that the sensitivity of the evaluation method of the degree of cure of the thermosetting resin in this embodiment is excellent.

[0099] The embodiments and examples disclosed herein are illustrative in all aspects and are not restrictive. The scope of the present invention is indicated by the claims rather than the embodiments and is intended to include all changes within the meaning and scope equivalent to the claims.

Claims

1. A method for evaluating the degree of curing of a thermosetting resin, which is a method for evaluating the degree of curing of a thermosetting resin obtained by a dehydration polycondensation reaction. The thermosetting resin obtained by dehydration polycondensation reaction refers to a thermosetting resin generated by multiple monomer compounds as raw materials of the thermosetting resin removing water molecules from each other's molecules and forming new bonds, so that the monomer compounds are linked together. The evaluation method includes: a step of preparing a sample containing the thermosetting resin; The step of maintaining the sample at a predetermined first temperature for a predetermined holding time to remove adsorbed water in the sample; The step of heating the sample after the step of removing the adsorbed water from the first temperature to a second temperature lower than the decomposition temperature of the thermosetting resin to generate a step of desorbing water; The step of calculating the mass of the generated desorbed water; and A step of evaluating the degree of curing of the thermosetting resin based on the mass of the thermosetting resin contained in the sample after the step of generating the desorbed water and the calculated mass of the desorbed water.

2. The method for evaluating the degree of curing of a thermosetting resin according to claim 1, wherein: The first temperature is 50° C. or higher and 100° C. or lower.

3. The method for evaluating the degree of curing of a thermosetting resin according to claim 1 or claim 2, wherein: The retention time is more than 30 minutes and less than 120 minutes.

4. The method for evaluating the degree of curing of a thermosetting resin according to claim 1 or claim 2, wherein: The step of generating the desorbed water includes heating from the first temperature to the second temperature at a heating rate of 50° C. / min or less.

5. The method for evaluating the degree of curing of a thermosetting resin according to claim 1 or claim 2, wherein: The second temperature is higher than 100° C. and lower than 400° C.

6. The method for evaluating the degree of curing of a thermosetting resin according to claim 1 or claim 2, wherein: The thermosetting resin is at least one selected from the group consisting of polyimide resins, phenolic resins, and amino resins.

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