JPH11258187A - Quality test method for recovered plasticizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a quality test method, for a recovered plasticizer, in which the quality of a plasticizer recovered from a synthetic resin product can be evaluated economically regarding its suitable use. SOLUTION: A quality test method. for a recovered plasticizer finds the composition of a plasticizer component contained in a synthetic resin product. The quality test method finds the standard function curve of a temperature and an endothermic amount under a prescribed measuring condition by using a differential thermal analysis regarding a standard plasticizer having the comsposition. The quality test method finds the standard value of the peak temperature or the like of the endothermic amount on the basis of the standard function curve. The quality test method finds the sample function curve of the temperature and the endothermic amount under the prescribed measuring condition by using a differential thermal analysis regarding a sample plasticizer recovered from a synthetic resin product. The quality test method finds the sample value of the peak temperature or the like of the endothermic amount on the basis of the sample function curve. The quality test method finds the difference value between the standard value and the sample value. The quality test method finds the quality grade of the plasticizer or of a mixed plasticizer sample in such a way that the difference value is substituted into a difference-value-quality grade function which is set in advance regarding the difference value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for testing the quality of a recovered plasticizer, and more particularly, to recycling and reusing a plasticizer separated and recovered from a synthetic resin molded article or scrap containing a plasticizer. The present invention relates to a quality test method applied to determine whether or not quality suitable for a use is maintained.

[0002]

2. Description of the Related Art At present, various kinds of synthetic resins are used, and accordingly, the types and amounts of synthetic resin wastes are increasing. However, discarding as it is only causes pollution of the global environment. It is not desirable from the viewpoint of effective use of resources. For this reason, methods of recovering and reusing synthetic resin waste that can be regenerated have been studied. Among them, the thermoplastic resin is relatively easy to reuse. In particular, scrap products etc. generated during the synthetic resin molding process are mixed with the raw synthetic resin by sorting and pulverizing, etc., and the production of processed products again It is common to use it.

[0003] However, if synthetic resin discarded after it has been used as a product is mixed with foreign substances or deteriorated in quality, the quality of the processed product using the collected resin may be impaired. Depending on the quality of the resin, it is necessary to select whether to use it again as a synthetic resin, to use it as a raw material for producing a synthetic resin, or to use it as an energy source such as fuel. Therefore, for general-purpose thermoplastic resins, such as polyethylene, polypropylene, polystyrene, and polyester, which are relatively easy to collect and separate, evaluate the degree of deterioration in order to determine the intended use of the collected product. Various methods have been proposed.

[0004] On the other hand, vinyl chloride resins produced in large quantities like the above-mentioned general-purpose resins have compositions having various physical properties from soft to hard depending on the amount of a plasticizer incorporated therein. It is used for various purposes by utilizing this feature. For this reason, vinyl chloride resin is made into a vinyl chloride resin composition of various formulations corresponding to each application, and is processed into a vinyl chloride resin product having characteristics according to each purpose, so it is used for various processed products. It is not easy and extremely complicated to evaluate the degree of deterioration of the obtained resin composition, and it has been considered difficult to recover and reuse the vinyl chloride resin product.

However, it is important to find a way to recover and reuse even a vinyl chloride resin product, and if it is difficult to reuse it as a composition, it may be necessary to reuse it as a raw material. . By the way, since a relatively high purity plasticizer is used as one of the raw materials of the vinyl chloride resin composition, a test method for quality control is defined. On the other hand, plasticizers recovered by methods such as extraction from polyvinyl chloride resin products often contain impurities, etc., and are used to determine whether or not they have reusable quality. There was no economic test method, and plasticizer recovery and recycling had not progressed.

[0006]

SUMMARY OF THE INVENTION In view of the circumstances, it has been considered difficult to reuse a plasticizer recovered from a vinyl chloride resin product because there is no method for simply evaluating the quality of the plasticizer. Provides a quality test method for plasticizers recovered from synthetic resin products, such as vinyl chloride resin compositions, to economically evaluate the quality of plasticizers that are suitable for which applications. The purpose is to do.

[0007]

According to the present invention, there is provided a method for testing the quality of a recovered plasticizer, which comprises determining the composition of a plasticizer component contained in a synthetic resin product, and determining the difference between a standard plasticizer having the above composition and a standard mixed plasticizer. Obtaining a standard function curve of temperature and endothermic amount under predetermined measurement conditions by calorimetric analysis, determining a peak value of the endothermic amount from the standard function curve, a temperature indicating the peak or a standard value of a half width of the peak, Obtaining a sample function curve of temperature and endotherm under the predetermined measurement conditions by differential calorimetry for the sample plasticizer or sample mixed plasticizer recovered from the synthetic resin product, and determining the peak height of the endotherm from the sample function curve. To determine the sample value of the half-width of the temperature or peak indicating the peak, to determine the difference between any of the standard values and any of the sample values corresponding thereto, and of the endothermic amount Peak height, temperature indicating the peak or the half value width of the peak, respectively, and the difference value corresponding to one of the preset difference value-quality class function is substituted for the quality class of the sample plasticizer or the sample mixed plasticizer. Seeking.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The recovered plasticizer to be subjected to the quality test method of the recovered plasticizer of the present invention is, for example, a soft vinyl chloride resin for covering electric wires, agriculture, building materials, miscellaneous goods, etc., or vinylidene chloride. It is a plasticizer recovered from a resin, a synthetic resin such as an acrylic ester-based resin, and in particular, a molded product, a paint, a scrap produced by using the synthetic resin, or a waste thereof. Such a plasticizer is separated into a resin component and a plasticizer component using a solvent or the like from a synthetic resin product containing the plasticizer as described above. Can be recovered through a process such as adding purification by vacuum distillation or the like. However, the recovered plasticizer to which the present invention is applied is not limited to the above-described recovery means, and may be one recovered by an appropriate method.

In applying the recovered plasticizer quality test method of the present invention, the recovered plasticizer of the same type as the recovered plasticizer to be subjected to quality evaluation is preliminarily subjected to a separation means such as chromatography and various physical or chemical methods. It is necessary to investigate the composition of the contained components using a statistical analysis means. Then, when the synthetic resin product from which the recovered plasticizer was extracted was manufactured, the type and composition of the plasticizer to be used were estimated, and the composition for manufacturing the synthetic resin product was estimated according to the above estimated composition and the like. Prepare the standard plasticizer that would have been used.

Further, when the standard plasticizer is a mixture of plasticizers, a plurality of control plasticizers whose compositions are deviated from the above-mentioned estimated composition are prepared. Prepare a degraded plasticizer or the like obtained by adding a thermal decomposition treatment or a hydrolysis treatment to the control plasticizer, and these can be used without any problem as a raw material of the synthetic resin composition, or synthesized when used as a raw material. It is desirable to investigate in advance how much the properties of the resin composition are impaired.

In the differential calorimetric analysis used in the method for testing the quality of the recovered plasticizer of the present invention, the sample can be heated at a predetermined rate from normal temperature to a temperature close to the heat resistance test temperature of the plasticizer. Any means capable of recording the amount of heat absorbed during the temperature rise of the sample or a change in the rate of temperature rise corresponding to the amount of heat absorbed can be used without any particular problem.

After such preparation, first, the above-mentioned differential plasticity analysis is performed on the above-mentioned standard plasticizer to examine the occurrence of an endothermic phenomenon at a heating rate of, for example, about 10 ° C./min. A graph between the measured values corresponding to the heat absorption amount, that is, a function curve as shown in FIG. 1 is created, and this is set as a standard function curve. In addition, in addition to the above, for the control plasticizer and the degraded plasticizer, etc., a function curve between the temperature and the endothermic amount is created in the same manner as described above, and the variation of the composition of the plasticizer and the progress of the degradation make the standard function Investigate in advance how the shape of the curve changes.

As described above, based on the control function curve and the deterioration function curve obtained for the control plasticizer and the deterioration plasticizer, the plasticizer which can be used as a raw material of the synthetic resin composition without any problem is absorbed by the standard function curve. The magnitude of a deviation from a value such as the peak height of the calorific value, the temperature at which the peak is shown, or the half-width of the peak, that is, how much the difference value is allowed is determined. And, for example, can be used alone as a raw material of the synthetic resin composition, can be used in place of a part of a good product,
Table comparing graded quality, such as can be used for other applications, with the magnitude of each of the above differences, i.e., endothermic peak height, peak showing temperature, or half the peak, respectively. It is desirable to prepare a table of the difference value-quality class function for the value range and the like.

After such preparation is completed, the relationship between the temperature and the endothermic amount, etc. of the sample of the recovered plasticizer to be tested is examined under the same measurement conditions as above using the aforementioned differential calorimetric analysis. , A sample function curve is determined. Then, the sample function curve and the standard function curve are compared, and the values of the endothermic peak height, the temperature indicating the peak, or the half width of the peak, and the values of the standard function curve are respectively compared with the sample function curve. Find the value of the difference. For at least one of these difference values obtained in this way, for example, according to the difference value-quality class function table prepared as described above, the quality of the recovered plasticizer is calculated from the difference value. Determine the class. At that time, if the sample function curve is almost the same as the standard function curve, the plasticizer is evaluated as having the same quality as a new standard plasticizer, and is graded to a quality grade equivalent to a standard product.

[0015] The recovered plasticizers thus rated for each quality class can be used for an appropriate application in accordance with the quality class. Can be used as a compounding material for

[0016]

EXAMPLE A vinyl chloride insulating coating for electric wires was dissolved in methyl ethyl ketone, methanol was added to remove precipitated solids, and then the solvent was removed to recover a plasticizer. Further, when the composition of the thus obtained recovered plasticizer was analyzed by gas chromatography, it was confirmed that the recovered plasticizer was mainly composed of 2-ethylhexyl phthalate (DOP).

Therefore, a new DOP (standard plasticizer) was subjected to differential calorimetric analysis to measure the temperature from 30 ° C to 330 ° C.
Heating was performed at a heating rate of 0 ° C./min to obtain a temperature-endotherm graph shown in FIG. This graph (standard function curve) shows almost the same result in five repeated measurements. From the average value of the data of those repeated measurements, the temperature (standard temperature) at which the endothermic peak of DOP shows a peak is 253. It was found to be 4 ° C.

Next, a temperature-endothermic graph (sample function curve) was obtained for the recovered plasticizer (sample plasticizer) under exactly the same measurement conditions as described above, and the endothermic amount was determined from the average value of five repeated measurements. 250.8 peak temperature (sample temperature)
° C was obtained. From these results, the difference between the standard temperature and the sample temperature was calculated to be 2.6 ° C.

Therefore, 100 parts by weight of a vinyl chloride resin having a polymerization degree of 1300, 48 parts by weight of a plasticizer, 47 parts by weight of a filler,
According to the test composition of 3 parts by weight of the calcium zinc-based stabilizer and 2 parts by weight of the lubricant, a soft vinyl chloride resin composition is produced using a Henschel mixer, and further roll-kneaded.
Pressed at ° C. to make a 1 mm thick vinyl chloride resin sheet using a standard plasticizer and a 1 mm thick vinyl chloride resin sheet using a part of the standard plasticizer with a recovered plasticizer. .

A comparison of the kneading processability of these compositions reveals that the recovered plasticizer has exactly the same kneading processability as the standard plasticizer. Further, for each vinyl chloride resin sheet obtained from these compositions, hardness, tensile strength, and mechanical properties such as elongation were compared,
The recovered plasticizer is almost the same as the standard plasticizer and has good thermal stability in heat resistance, but shows an increase in hardness due to thermal aging and a tendency to increase the low-temperature embrittlement temperature. Was.

From the above, it was found that the peak temperature of the endothermic amount of the recovered plasticizer was about ± 4 ° C. compared to that of a new plasticizer, obtained from the temperature-endothermic function curve obtained by differential calorimetry. If it is the difference, by slightly modifying the composition, or by replacing and using up to about 1/2 of the new plasticizer, it has the same characteristics as the composition using the standard plasticizer. It has been found that the composition can be manufactured.

[0022]

According to the method for testing the quality of the recovered plasticizer of the present invention, the function curve of temperature-endotherm is measured by differential calorimetry to determine the recovered plasticizer obtained from a synthetic resin such as a vinyl chloride resin. Since the quality can be easily determined, there is an effect that a new way of using synthetic resin products and the like, which has been conventionally difficult to reuse, can be opened, and effective use of resources and prevention of environmental pollution can be achieved.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a temperature-endothermic function curve obtained by differential calorimetry in the quality test method of a recovered plasticizer of the present invention.

Claims (2)

[Claims] The present invention relates to a method for determining the composition of a plasticizer component contained in a synthetic resin product. Determining a standard function curve, determining a standard value of a peak height of an endotherm, a temperature indicating a peak or a half-width of a peak from the standard function curve, and a difference between a sample plasticizer or a sample mixed plasticizer recovered from a synthetic resin product. Obtaining a sample function curve of temperature and endothermic amount under the predetermined measurement conditions by calorimetric analysis, and obtaining a peak value of the endothermic amount, a temperature indicating the peak, or a sample value of a half value width of the peak from the sample function curve. Determining the difference between any of the standard values and any of the corresponding sample values;
And the peak value of the endothermic amount, the difference value corresponding to one of the preset difference value-quality class function with respect to the temperature indicating the peak or the half width of the peak, and substituting the sample plasticizer or the sample mixed plasticity. Determining the quality grade of the recovered plasticizer. 2. The method according to claim 1, wherein the difference value is a difference value between a standard value of the temperature indicating the peak and a sample value, and the difference value-quality class function sets a temperature set for the temperature difference value indicating the peak. The method for testing the quality of a recovered plasticizer according to claim 1, which is a difference value-quality function.