JPS60117151A - Analysis of uncured epoxy resin composition - Google Patents

Abstract

PURPOSE:To perform the accurate quantitative analysis of a compounded component, by sampling an extremely minute amount of a specimen from an uncured resin composition prior to being used in injection molding work to insert the same into a thermal decomposition apparatus and gasifying the same to form thermally decomposed gas which is, in turn, applied to a gas chromatograph. CONSTITUTION:A specimen S is a resin composition mixed in an injection molding work factory and sampled therein or a reference specimen of which the compounding ratio is known and, because of a liquid, said specimen S is allowed to impregnate quartz wool and packed by a metal foil to be thrown into the heating cylinder 11 of a thermal decomposition apparatus 10 while air in the heating cylinder 11 is purged with purge gas from a bomb 26. As a heating means, an induction heating coil 12 receiving a current from a high frequency power source 14 is arranged around the heating cylinder 11. Thermally decomposed gas is issued from the heating apparatus 10 through a valve 13 along with carrier gas and enters the absorbing column part 23 of a gas chromatograph analytical apparatus while an analysis signal is outputted by a detector 24 and recorded by a recordor 30 or integrated by an integrator 40.

Description

Detailed description of the invention [Technical field to which the invention pertains] The present invention relates to an uncured resin composition containing an epoxy resin base, an acid anhydride curing agent, and a plasticizer, and in which these components are mixed or mixed. Under the Gas Cromatograph Law of the compounding ingredients in the object] (Conventional technical student that problem) 〇 [Traditional technical students that are the problems] Note For forming, impregnated or adhesive work, the above -mentioned epoxy resin main agent, curing agent and plastic. Resin compositions containing additives are used in large quantities in formulations that contain fillers or do not contain fillers.After curing such resin compositions, it is difficult to obtain cured resin products with excellent electrical or mechanical properties. It is absolutely necessary to make the blended component ratio accurate, and this consideration cannot be overlooked, especially for furnaces for electrical and electronic applications. It is necessary to confirm the blended component ratio before starting the injection/impregnation work, but since the blended components themselves as materials to be mixed are organic polymer compounds or resins, the qualitative characteristics of the components cannot be determined. Even analysis is difficult, and in the past it was considered extremely difficult or impossible to accurately measure the blending ratio. In addition, in this type of work process, especially when molding a resin composition containing a large amount of highly viscous resin admixtures or fillers, it takes time to measure the blended component ratio. There is no point in analytical measurement if it is necessary, and there are difficulties from this point. □ Due to the circumstances mentioned above, the company has decided to use a method for checking resin compositions before casting and impregnating operations. Simple methods are preferred, and in many cases the check can be completed simply by measuring the viscosity of the composition using a 4-line plate viscometer, etc., and the meaning of the viscosity measurement itself is sufficient.
This is a rather roundabout method that is far removed from the 41 experience.

In addition, the gelation time of a resin mixture is often measured as a preliminary check, but it is unavoidable that it takes some time for the resin mixture to solidify into a sherry-like shape when it is placed in a container and heated. It is not always easy to keep the exothermic state constant during the curing reaction, and as with soap, there is little significance in formulation analysis.

On the other hand, as a chemical analysis method, excess hydrochloric acid is made to act on the 7 groups in the resin material in an appropriate solvent to produce chlorohydrin, and the excess hydrochloric acid that did not participate in the production is removed from the alkali. Methods for determining the amount by titration of a specified solution9 or titration with silver nitrate are known, but most people use this method for determining the base ingredient of epoxy resin, and it is not suitable for determining other ingredients. I can't get it.

Furthermore, as a so-called instrumental analysis method, infrared or far-infrared absorption spectroscopy, which measures the resin composition sample as it is, is known.
1850 due to infrared absorption of 10m” and acid hydride in the curing agent.
cm'' infrared absorption, and the blending ratio of the main agent and curing agent can be determined from the ratio of both absorption intensities, but it cannot be used to quantify the plasticizer. Methods that utilize infrared absorption spectra and thermal separation infrared absorption spectroscopy are also known, but essentially the same method as before is used.
A method of determining the absorption intensity ratio of an enyl group and an acid anhydride,
This method is not suitable for measuring resin compositions containing plasticizers, and even when combined with other methods, it takes time to quantify, so practical problems remain.

[Purpose of the invention]

The present invention is based on the recognition of the problems of the conventional analytical methods as described above, and aims to measure the blended components or blending ratio of the base agent, curing agent, and plasticizer in a single measurement with sufficient accuracy for practical use. The purpose of this study is to establish a method for quantitative analysis of uncured epoxy resin compositions.

[Key points of the invention]

According to the present invention, the above-mentioned object is achieved by using an instrumental analysis method using the Gas Kron Toge 27 method as the main analysis method, and using the resin composition as a measurement gas to be analyzed by the Gas Kron Toge method by rapid heating. Using thermally decomposed pyrolysis gas, the pyrolysis gas was prepared under almost the same mixing conditions as the resin composition to be analyzed, with respect to the peaks representing the respective compounded components in the gas chromatogram shown by the pyrolysis gas. This is achieved by quantitatively analyzing the ingredients of a resin composition containing an epoxy resin base, an acid anhydride curing agent, and a plasticizer in comparison with a reference value determined from a reference sample. As can be seen from the above structure of the method of the present invention, the gas to be analyzed by gas chromatography is not a gas in which the compounded components themselves have evaporated;
It is a gas of an organic compound different from that of the compounded components, which is generated by thermal decomposition of the compounded components, and there is no need to identify the type of pyrolysis gas for the purpose of the method of the present invention. found that each compounded component can vary the absorption of thermally decomposed gas from the gas chromatograph 27 or the re-release characteristics from the column agent. In terms of the reliability of the quantitative method and the reproducibility of the quantitative results, careful consideration must be given to the fact that the mixed or mixed resin i acid is susceptible to chemical changes. It was found that the analysis results may vary depending on the holding temperature of the resin composition after blending and the elapsed time after blending. Therefore, in the method of the present invention, as a reference sample for obtaining a test line for quantifying analytical data, a sample with a known blending ratio and mixed at approximately the same temperature as the test resin composition is used. Using this standard test sample as a calibration curve, the analysis results of gas chromatography using the same column absorbent as the one used for the analysis of the test composition were used to calculate the analytical data of the test resin composition, including the amount of ingredients. By quantifying the strength of the compounding ratio, we can obtain reproducible and reliable analytical results.'0 Regarding the mixing temperature of the resin composition or reference sample mentioned above, the commonly used epoxy resin base resin is bisphenol-based. A, when the curing agent is an ordinary acid anhydride type, 80'C
The following is desirable, and in this case, the elapsed time after 1111 of the standard sample entered into the gas chromatograph analysis and the elapsed time from mixing the test resin composition to sampling, even if there is a difference. , the quantitative analysis results are reliable.

However, even if the above-mentioned mixing temperature exceeds 8°C due to work reasons, the elapsed time after preparation of the standard sample and the elapsed time until sampling of the test resin composition will not exceed 1.
111 By combining the same values, it is possible to obtain quantitative analysis results that are reliable in practice. [Embodiments of the Invention] Examples of the present invention will be described in detail below with reference to the drawings.

#! Figure 1 shows an example of an analyzer used in carrying out the method of the present invention, which includes a thermal decomposer IQ that heats and thermally decomposes a sample S, and a gas chromatograph analyzer body 20.
．． It consists of a recording device 3'o that draws a chart of analysis results, a digital integration device 40 that integrates and types out the area of the mountain on the gas chromatograph 2, etc. Sample 3 was mixed and sampled at the end of the casting operation. A resin composition or compounding ratio d ([This is a known standard specimen, made of quartz wool etc. with The lid 1 on the top of the heating cylinder 11
1b is opened and put in, and placed on the porous shelf 11a of the heating cylinder 11. This metal foil material is made of an iron-cobalt-nickel alloy, as is well known, and can be used as a sample holder to thermally decompose the sample at a predetermined temperature, depending on the heating temperature. In this state, with the valve 13 at the position shown by the chain line, a purge gas such as nitrogen from the pump 26 is flowed from the upper part of the heating cylinder 11 in the direction of the arrow of the chain line to purge the air inside the heating cylinder.

As a heating means, a high frequency power source 14 is installed around the heating tube 11.
The induction heating coil 12 that is powered by the
To start heating, first switch the valve 13 to the direction shown by the solid line, then adjust the carrier gas, for example helium, from the cylinder 25 to a predetermined pressure according to the indication from the pressure gauge 22 using the valve 21. The metal foil of Sample S is heated by induction to thermally decompose the resin composition therein in a short period of about 2 seconds.

The thermally separated gas generated at this time exits the heating device 1° from the bottom of the heating cylinder through the valve 13 together with the carrier gas, enters the absorption column section 23 of the gas chromatograph analyzer shown on the right side, and enters the absorption column section 23 of the gas chromatograph analyzer shown on the right side. Detector 24 generates a Lugas chromatog 27 signal. This detector is
Detector 2, which is suitably a hydrogen ionization detector (FID)
The four signals are input to a recording device 30, and a gas chromatogram (char) 30a is output. Also, the detector 24
These signals are simultaneously input to an integrator 4o, and the area of a predetermined peak in the gas chromatogram is calculated in a known manner and output as data 40a.

Next, a method for quantitatively analyzing the components of the resin composition from the data of the gas chromatogram or integration results obtained in this manner will be described. Figure 2 is an example of a gas chromatogram of the pyrolysis gas of resin composition sample S, and as can be seen from the figure, many peaks or mountains are observed, and each peak corresponds to a different type of cracked gas. It is.

In addition, as is well known, the area of each peak contains information indicating the amount of decomposed gas.
If you separate the types and know the amount of each type, in principle,
It should be possible to measure the amount of each ingredient, but
All of these peaks contain information useful for mutual separation of gas mixtures. In other words, it is true that different compounding components generate the same pyrolysis gas, and from the peak of the gas chromatogram shown by such kind of decomposition gas, it is possible to calculate the sum of the plurality of compounding components that generate carcass decomposition gas. This is because even if it is known, the amount of one type of compounded component cannot be separated and quantified from other compounded components. What is even more troublesome is that the peaks in the gas chromatogram may overlap even if the cracked gas is different. It is generally difficult to separate peaks when gases have similar molecular structures or properties. Figure 3 shows resins R9 curing agent H1 lubricant P and curing accelerator that are blended into a practical epoxy resin composition. This shows an example of a gas chromatogram of pyrolysis gas separated under the same conditions as in Figure 2 for A and the colorant alone. Similarly, each of them contains many peaks, and these peaks overlap each other. It can be seen that the gas chromatogram of the resin composition shown in FIG. 2 is obtained. For this reason, among the large number of peaks in the pyrolysis gas chromatogram of a resin composition, the peaks useful for quantifying the helium component are rather limited.

According to the results of experiments, the main ingredient of the epoxy resin is Bil A type, the curing agent is an acid anhydride type, especially 7-tar acid type acid anhydride, and the plasticizer is typically propylene glycol. In case Ka, the peak of cracked gas useful for quantifying the resin base is the peak P shown in Figure 2.
The pyrolysis gas component was identified as acrylic aldehyde by mass spectrometry. The gas component of this decomposition is presumed to be the thermal decomposition of the epoxy functional groups in the epoxy resin polymer, and a large amount of allyl alcohol is generated as a decomposition gas from the functional groups, but the skeletal part of pisphenol A Fux generated as a thermally separated gas from
-# As with Yap-Impropenylfeshield, examples of peaks that are useful for quantifying curing agents that are not very useful from the perspective of composition separation are those shown by PH in Figure 2.
The cracked gas component is 0-cresol. As shown in Figure 3, the gas chromatogram H of the curing agent has a large peak that is thought to originate from the skeleton of the curing agent, but Figure 2 shows an example of a peak for quantitative determination of plasticizer, which is inappropriate from the standpoint of compositional separation. When the plasticizer is propylene glycol, this peak, which is identified as propylene, is advantageous because other cracked gases such as acetone and acetaldehyde are also large. These results are based on the use of "Tl1NAx-GC (60/80 mesh)" manufactured by Nippon Chromato Industries Ltd. as a column absorbent for gas chromatography analysis, and if the column absorbent is changed, the ingredients will naturally change. The gas chromatogram peaks suitable for quantitative determination are also somewhat distinct. Other column absorbents suitable for carrying out the present invention can also be used, such as the product name [Avinishing Grease L]. It is possible. Figure 4 illustrates the results of the experiment. Figure (a) shows the correlation between the thermal separation temperature T and the data dispersion 0 The same figure (b) similarly shows the influence of thermal decomposition time, and it can be seen that about 2 seconds is appropriate.

Furthermore, since the reaction of the resin composition mixed as described above progresses over time, it is necessary to confirm the reliability of the analysis results from this point of view as well. FIG. 5(a) shows the results of tracking the degree of reaction after mixing the resin base material and curing agent using an infrared method.

The mixed resin contains 100 parts by weight of the base bisphenol A resin and 100 parts by weight of the acid anhydride curing agent. In addition to 20 parts by weight of plasticizer, 360 parts by weight of silica-based inorganic filler. A standard casting resin composition containing 0.4 parts by weight of a curing accelerator and 3 parts by weight of a coloring agent.Measurements were made at two points, 1850 cm for the phenyl group and 1610 cm for the curing agent, and the vertical axis of the figure is for the latter. The holding temperature during and after mixing was Ti = 80°C) and 'l'u (=95°C). It can be seen that the results are unreliable unless the reaction is quick and the sample is sampled early.

Furthermore, Φ), (e), and (d) in the same figure show the results of tracking the area of peaks PR, PH, and PP in the gas chromatogram mentioned above for the resin base, curing agent, and plasticizer, respectively. For m++v, a standard substance (for example, DO'E') that does not participate in the reaction even after mixing is added to the resin composition in advance, and the peak area of the chromatogram shown by this standard substance and the area of each of the above-mentioned peaks are calculated. Changes over time were measured by the ratio of 1 to 1, and the figure shows the ratio of 1 immediately after mixing to 1. As can be seen from these figures, at temperature TI, the change over time is small, but at temperature Tu, it is clear that the elapsed time until sampling should be controlled. In the case of compounding, it is carried out at a temperature between 80 and 90°C.

The time required for uniform stirring is usually about 1 hour, and according to actual measurements, the mixing temperature is 90℃.
In this case, it has been confirmed that the analysis result #1 is reliable if the elapsed time until the specimen sample is completed is about 2 hours. Based on the gas chromatogram 30a or integral value data 40a obtained by the method and method, a resin mixture with a known distribution ratio within the measurement range is determined based on the amount of each compounded component or compounding ratio. A calibration curve is prepared based on the above-mentioned data obtained by preparing several types of reference samples with a mixing ratio of 1 and using a measuring device and a measuring method for the test object. Figure 6 shows an example of the test line, YR.

YH and YP are the peaks PR, PH, and PP in Figure 2, respectively.
This is the integral value obtained from . Figure (a) is an example of a calibration curve for a curing agent, which shows the ratio of the integral data value π for the resin base to the integral data value ■ for the curing agent YH/Y R
is shown on the vertical axis. The horizontal axis is the ratio of the amount of curing agent to the amount of the main agent, that is, the specific pressure of the curing agent to the main agent.Similarly, in Figure (b), the vertical axis shows the ratio of the amount of plasticizer to the data value of the main agent. Ratio of data value YP YP/
In YR, the mixing ratio XP of the plasticizer to the main ingredient is shown on the horizontal axis. As can be seen from Figures (a) and (b), the mixing ratio (■) for the curing agent is in the range of 0.8 to 1.2, and the mixing ratio XP for the plasticizer is in the range of 0.0 to 1.2. The calibration curve has very good linearity in the range of 0.5. If such a calibration curve is used, three pieces of data obtained from the subject, YR,
By calculating the ratios Ya/YR and YP/YR from YH and YP and using the calibration curves shown in FIGS. 6(a) and (b), the blending ratios XH and XP can be immediately determined.

The expanded table shown below shows an example of quantitative analysis values obtained using this tabular method, and shows the quantitative analysis values for a resin composition as a test object having the composition shown as the theoretical value on the left side of the table. As shown in the 0 example shown on the right side of the table, the degree of agreement between the theoretical value and the analytical value is high, and it can be seen that the quantitative analysis results obtained by the method of the present invention are sufficiently reliable. Note that the numbers in the second row in each column of analysis values indicate the analysis results in Figure 2. The results of five or more analyzes of the samples shown in the example in the table above show that the standard deviation of the measured values was about 2-2% of the average value for the base agent and curing agent, and about 5% for the plasticizer.

The present invention is not limited to one or more of the embodiments described, but can be implemented in various modified embodiments.For example, the conditions for generating pyrolysis gas to be analyzed by gas chromatography may be as explained in FIG. The temperature may be shifted above or below the best conditions, and as long as the pyrolysis temperature is in the range of 400 to 650°C, there will be no major difference in the composition or amount of the thermally separated gas generated, and the pyrolysis time will also be within the shortest possible time. Although it is necessary to gasify the gas for about 1 to 4 seconds, it is suitable for gas chromatographic analysis.In addition, as explained above, the cracked gas that produces peaks representative of each compounded component in the gas chromatogram. The compounds in the table are just examples, and if the types of each compounded component are different, the types of compounds will naturally differ, and a compound that is compatible with that should be selected as a representative. Regarding the sampling conditions and the mixing and preparation conditions of the standard sample for creating the calibration curve, it is possible to expect more accurate analysis results if the conditions are as close to each other as possible. Practical and reliable analysis results can be obtained even if the values are different. However, it is always important to remember that there is a possibility that the reaction will proceed after mixing resin mixtures, so the mixing temperature and subsequent holding temperature must be adjusted in particular. The lower the value, the greater the freedom of sampling and preparation conditions.
As mentioned above, if this temperature is below 80°C, this condition control can be done gently, and if the conditions are carefully controlled up to about 90°C, sufficiently reliable results can be obtained, but if the temperature is higher than this, This should be avoided as it becomes difficult, if not impossible, to manage.

〔Effect of the invention〕

According to the method of the present invention, a very small amount of the specimen is sampled from the uncured resin composition after mixing the epoxy resin (with the curing agent and the plasticizer) before use in casting work, etc., and then heated. By inserting the gas into the decomposition device and subjecting the pyrolysis gas to a gas chromatograph, it is possible to accurately quantitatively analyze the compounded components.Based on the analysis results, the resin compound can be finely adjusted just before casting, resulting in hardening. It can stabilize the electrical and mechanical properties of the subsequent resin composition.As mentioned above, even if the sample is sampled under normal work site conditions, the accuracy of analysis may be a practical problem. Since the four steps for analysis are simple, it does not require experts who are skilled in quantitative analysis.Furthermore, the method of the present invention allows practical formulation of resin compositions containing plasticizers, etc., which has not been done in the past. This has paved the way for the practical application of quantitative analysis of components, and even if the resin composition contains curing accelerators, colorants, and even inorganic fillers, there is no particular problem in analysis.The time required for measurement is Since it takes about 30 minutes at most, analysis results can be obtained within the time required for blending and uniformly stirring the resin at the work site.

As described above, the method of the present invention is a practical quantitative analysis method for uncured epoxy resin compositions that is suitable for on-site quality control such as epoxy resin casting work and for fine adjustment of compounded ingredients and has sufficient accuracy. It is possible to provide

[Brief explanation of drawings]

All of the figures show examples of the present invention, and Figure 1 is an explanatory diagram of the configuration of an analyzer used in carrying out the method for analyzing uncured epoxy resin compositions according to the present invention, and Figure 2 shows the analysis method according to the present invention. Fig. 3 is a gas chromatogram of the pyrolysis gas of the resin composition to be analyzed, and Fig. 4 is a gas chromatogram of the pyrolysis gas of the compounded components contained in the resin composition to be analyzed. Figure 5 is a graph showing the influence of thermal decomposition conditions of the composition on the measurement results; Figure 5 is a graph showing the influence of the conditions from mixing the resin composition to sample sampling on the measurement results; Figure 6 is an example of a calibration curve for quantitative analysis drawn from the results of gas chromatography analysis of a standard sample. In the figure, 10 is a thermal decomposition device for thermally decomposing the resin composition to be tested, 20 is a gas chromatograph analyzer for gas chromatographic analysis of pyrolysis gas, and 23 is a gas absorption column for gas chromatographic analysis. To the ward Q) Mori

Claims (1)

[Scope of Claims] 1) A main agent consisting of an epoxy resin as a compounding component. A method of quantitatively analyzing the components in an uncured resin composition containing at least an acid anhydride curing agent and a plasticizer, and in which the components are mixed or mixed, by gas chromatography 6 In this method, a pyrolysis gas obtained by thermally decomposing the resin composition by rapid heating is used as a measurement gas to be analyzed by gas chromatography, and each of the above-mentioned formulations in the gas chromatogram shown by the skeleton pyrolysis gas is Mixing conditions of the resin composition to be analyzed regarding peaks representative of the components Potato #1 is quantitatively analyzed by comparing the blended components of the resin composition with a reference value determined from a reference sample prepared under the same conditions. A method for analyzing an epoxy-based uncured resin composition. 2. In the method according to claim 1, the epoxy resin composition sample is thermally decomposed at a thermal decomposition temperature of 400 to 650°C to generate a thermally separated gas to be analyzed by gas chromatography. System uncured 4! Method for analyzing leg composition. 3) 4I, Claim No. 1. 3. A method for analyzing an uncured epoxy resin composition according to item 1 or 2, wherein the thermal decomposition time of the resin composition sample is 1 to 4 seconds. 4) 4! In the method according to claim 1, an uncured epoxy resin characterized in that a peak of acrylic aldehyde is used as a peak in a gas chromatogram of a pyrolysis gas representative of the epoxy resin main ingredient. Methods for analyzing compositions. 5)! In the method according to claim 1, an epoxy uncured resin composition characterized in that a peak of orthocresol is used as a peak in a gas chromatogram of a pyrolysis gas representative of an acid anhydride curing agent. 6) In the method described in claim 1, the plasticizer blended and combined with the resin composition IR5 is a propylene glycol-based plasticizer, and the gas chroma of a pyrolysis gas representative of the plasticizer is Method for analyzing an uncured epoxy resin composition, characterized in that the peak of propylene is used as the peak of the tomogram 07) In the method according to claim 1, the reference sample is mixed i! A method for analyzing an uncured epoxy resin composition, characterized in that the l1M temperature is the same as the mixing temperature of the resin composition to be analyzed. 8) A method for analyzing an epoxy uncured resin composition in the method described in claim 7, characterized in that the mixing temperature of the reference sample is 90°C or lower. 9) Claim 1 8. A method for analyzing an uncured epoxy resin composition, characterized in that the sample of the resin composition to be analyzed by gas chromatography is sampled within 2 hours after mixing of the ingredients. 10) % In the analytical method according to claim 1,
A method for analyzing an uncured epoxy resin composition, which comprises comparing the results of a gas chromatographic analysis of a resin composition sample with a calibration curve drawn from a reference value obtained from a reference sample.