Method for measuring discharge amount of aldehyde from olefin resin

Abstract

To provide a method for easily measuring the discharge amount of aldehyde from an olefin resin containing a black component and talc.SOLUTION: A method for measuring the discharge amount of aldehyde from an olefin resin containing at least one selected from the group consisting of a black component and talc includes: removing the at least one selected from the group consisting of the black component and the talc from the olefin resin and obtaining a resin for light emission measurement; measuring a slight amount of light emission from the resin for light emission measurement by a chemiluminescence method; and determining the discharge amount of aldehyde from the olefin resin on the basis of the slight amount of light emission.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a method for measuring the amount of aldehyde released from an olefin-based resin. [Background technology]

[0002] In order to reduce the amount of volatile organic compounds (VOCs) inside an automobile, it is required to reduce the amount of VOCs emitted from the interior materials of the automobile. The general method for measuring the amount of VOCs emitted is the sampling bag method, but the sampling bag method requires complicated and time-consuming work steps. Therefore, a method capable of easily measuring the amount of VOCs emitted from the interior materials of a vehicle is required. Patent Document 1 describes a method for measuring the amount of formaldehyde emitted from a polyacetal resin molded article. In this method, the amount of formaldehyde emitted from a polyacetal resin molded article is measured based on the maximum amount of weak luminescence measured from the polyacetal resin molded article. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-169931 A Summary of the Invention [Problem to be solved by the invention]

[0004] Olefin resins used as interior materials for automobiles often have low brightness and therefore often contain black components such as carbon black. Black components absorb weak luminescence. Olefin resins used as interior materials often contain talc. Magnesium oxide contained in talc emits light, which causes noise in the measurement of the amount of weak luminescence. Therefore, it is difficult to measure the amount of weak luminescence of olefin resins containing black components or talc. Therefore, the method described in Patent Document 1 cannot be applied to the measurement of the amount of aldehyde released from olefin resins containing black components or talc.

[0005] Therefore, a method for simply measuring the amount of aldehyde released from an olefin resin containing a black component or talc is provided. [Means for solving the problem]

[0006] Aspects of the present disclosure include the following. [Aspect 1] A method for measuring an amount of aldehyde released from an olefin resin containing at least one selected from the group consisting of a black component and talc, comprising: removing at least one selected from the group consisting of the black component and talc from the olefin-based resin to obtain a resin for luminescence measurement; measuring the amount of weak luminescence from the luminescence measuring resin by a chemiluminescence method; determining an amount of aldehyde released from the olefin-based resin based on the amount of weak luminescence; A method comprising: [Aspect 2] removing at least one selected from the group consisting of the black component and talc from the olefin resin to obtain the resin for luminescence measurement, dissolving the olefin-based resin in a solvent to obtain a solution; removing at least one selected from the group consisting of the black component and talc from the solution; evaporating the solvent in the solution to obtain the resin for luminescence measurement; 2. The method of embodiment 1, comprising, in order: [Aspect 3] 3. The method of claim 2, wherein removing the at least one selected from the group consisting of the black component and talc from the solution comprises filtering the solution. [Aspect 4] The method according to any one of aspects 1 to 3, wherein the olefin-based resin is a polypropylene-based resin. [Aspect 5] The method according to any one of aspects 1 to 4, wherein the aldehyde is acetaldehyde. Effect of the Invention

[0007] The method of the present disclosure makes it possible to easily measure the amount of aldehyde released from an olefin-based resin that contains a black component or talc. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a graph showing the correlation between the amount of acetaldehyde released from a sample measured in an example and the amount of weak luminescence from a sample from which inhibitory components have been removed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] A method for measuring the amount of aldehyde released from an olefin resin containing at least one selected from the group consisting of a black component and talc according to an embodiment will be described.

[0010] In the present application, an olefin-based resin is a resin containing olefin units in an amount of more than 50 mol% and not more than 100 mol% when all the structural units constituting the resin are taken as 100 mol%. When a plurality of structural units corresponding to olefin units are contained, the total amount of all the olefin units is more than 50 mol% and not more than 100 mol%. An example of an olefin-based resin is a polypropylene-based resin. In the present application, a polypropylene-based resin is a resin containing propylene units in an amount of more than 50 mol% and not more than 100 mol% when all the structural units constituting the resin are taken as 100 mol%. Examples of polypropylene-based resins include propylene homopolymers (homopolypropylenes), propylene-α-olefin copolymers (random polypropylenes), propylene block copolymers (block polypropylenes), and combinations thereof.

[0011] The olefin resin contains at least one selected from the group consisting of a black component and talc. An example of the black component is carbon black. Since the black component and talc inhibit the measurement of weak luminescence by chemiluminescence, in the present application, "at least one selected from the group consisting of the black component and talc" is appropriately referred to as "inhibitory component".

[0012] The olefin resin may further contain components such as additives and fillers. Examples of additives include antioxidants, neutralizing agents, light stabilizers, ultraviolet absorbers, crystal nucleating agents, antiblocking agents, lubricants, antistatic agents, and metal deactivators. These additives may be used alone or in combination of two or more. Examples of fillers include inorganic fillers such as calcium carbonate, silica, hydrotalcite, zeolite, aluminum silicate, magnesium silicate, glass fiber, and carbon fiber, and organic fillers such as crosslinked rubber fine particles, thermosetting resin fine particles, and hollow thermosetting resin fine particles.

[0013] Examples of aldehydes include acetaldehyde and formaldehyde, which are VOCs. In particular, acetaldehyde has a low boiling point (21°C) and a low indoor concentration guideline value (48 μg / m 3 ).

[0014] The method for measuring the amount of aldehyde released from an olefin-based resin containing at least one type (inhibitory component) selected from the group consisting of a black component and talc according to an embodiment includes removing the inhibitory component from the olefin-based resin to obtain a resin for luminescence measurement (step S1), measuring the amount of weak luminescence from the resin for luminescence measurement by a chemiluminescence method (step S2), and determining the amount of aldehyde released from the olefin-based resin based on the amount of weak luminescence (step S3).

[0015] (1) Step S1: Removal of inhibitors The inhibiting components are removed from the olefin resin to obtain a resin for subsequent measurement of the amount of luminescence (resin for luminescence measurement). An example of a specific method for removing the inhibiting components from the olefin resin will be described.

[0016] First, an olefin resin containing an inhibitor is dissolved in a solvent to obtain a solution. The inhibitor does not dissolve in the solvent, so it exists as a solid component in the solution. Any volatile liquid capable of dissolving the olefin resin can be used as the solvent. Examples of solvents that can be used include xylene, dichlorobenzene, and polychlorobenzene. Xylene is particularly preferable because it is inexpensive. The solvent may be appropriately heated to promote dissolution of the olefin resin. For example, when the olefin resin is a polypropylene resin and the solvent is xylene, the solvent may be heated to 120°C to 140°C.

[0017] Next, the inhibitors are removed from the solution. For example, the solution is filtered, so that the inhibitors remain as a residue, and the solution from which the inhibitors have been removed is obtained as a filtrate. The method for removing the inhibitors from the solution is not limited to filtration. For example, the inhibitors may be removed from the solution by centrifugation.

[0018] Next, the solvent in the solution from which the inhibitory components have been removed is evaporated to obtain a resin for subsequent luminescence measurement (luminescence measurement resin). The solvent may be evaporated by air drying or the like.

[0019] (2) Step S2: Measurement of faint light emission The amount of weak light emitted from the resin for luminescence measurement is measured by the chemiluminescence method. The chemiluminescence method is a method for measuring the weak light emitted when the organic peroxide contained in the oxidized resin is decomposed by heat. The measurement of the amount of weak light emitted by the chemiluminescence method can be performed in accordance with JIS K 7351:2018.

[0020] The measurement of the amount of weak luminescence may be carried out in an inert atmosphere, such as a nitrogen atmosphere, while heating the resin for luminescence measurement. The heating temperature may be appropriately set depending on the sensitivity of the measurement device, the type of resin, etc.

[0021] (3) Step S3: Calculation of the amount of aldehyde released The amount of aldehyde released from the olefin resin is calculated based on the measured amount of weak luminescence. Specifically, a relational expression between the amount of aldehyde released from the olefin resin and the amount of weak luminescence is calculated in advance, and the amount of aldehyde released is calculated by applying the measured amount of weak luminescence to the relational expression.

[0022] The relational expression between the amount of aldehyde released from the olefin resin and the amount of weak luminescence can be obtained as follows. That is, a plurality of olefin resins are prepared as standard samples, and the amount of aldehyde released from the standard samples is measured by any method such as the sampling bag method. The amount of weak luminescence of the standard samples is also measured by the same method as in step S2 above. From the measurement results of these standard samples, the relational expression between the amount of aldehyde released from the olefin resin and the amount of weak luminescence can be obtained. The fact that the amount of aldehyde released from the olefin resin and the amount of weak luminescence show a correlation is also shown in the examples described below.

[0023] The reason why the amount of aldehyde released from an olefin resin correlates with the amount of weak luminescence is presumed to be as follows. When an olefin resin is oxidized and deteriorated, acetaldehyde is generated. At this time, it is considered that organic peroxides are generated and remain in the olefin resin. Therefore, it is considered that the amount of organic peroxides in the olefin resin correlates with the amount of aldehyde released from the olefin resin. Therefore, the amount of weak luminescence derived from organic peroxides correlates with the amount of aldehyde released from the olefin resin.

[0024] The present invention is not limited to the above-described embodiment. Various modifications, additions, and deletions can be made without departing from the technical idea or scope of the present invention described in the claims. EXAMPLES

[0025] The present disclosure will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[0026] (1) Sample As olefin-based resin samples, one type of non-recycled polypropylene resin (manufactured by Japan Polypropylene Corporation) and four types of automotive-derived polypropylene resins (manufactured by Isono Corporation or Planic Corporation) were prepared.

[0027] (2) Removal of inhibitors and measurement of weak luminescence intensity by chemiluminescence 200 mg of each sample was dissolved in approximately 30 mL of xylene at 130°C to obtain a solution. The solution was filtered through filter paper. A black solid remained on the filter paper. The filtrate was air-dried on an aluminum cell with a diameter of 50 mm to evaporate the solvent. As a result, a circular sheet-shaped resin for luminescence measurement, 50 mm in diameter and approximately 1 mm thick, was obtained. The mass of the resin for luminescence measurement was measured.

[0028] The sample chamber of the extremely weak luminescence detection spectroscopy system (CLA-FS4 chemiluminescence analyzer, manufactured by Tohoku Electronics Industries Co., Ltd.) was heated to 150°C, and the luminescence measurement resin was placed in the sample chamber. The sample chamber was filled with nitrogen gas, and the amount of weak luminescence from the luminescence measurement resin was integrated for a specified time. The integrated value was divided by the mass of the luminescence measurement resin to determine the amount of weak luminescence (counts / mg) per 1 mg of luminescence measurement resin. The results are shown in Table 1.

[0029] (3) Measurement of acetaldehyde emissions using the sampling bag method Each sample was injection molded to a length of 100 mm, width of 80 mm, and thickness of 2 mm. Injection molding was performed using an M-70B-SJ injection molding machine manufactured by Meiki Seisakusho Co., Ltd., with a cylinder temperature of 240°C, a mold temperature of 40°C, an injection speed of 100 mm / sec, an injection time of 1.18 sec, and a cooling time of 20 sec. The molded products from the start of molding to the 5th shot were discarded, and the molded product from the 6th shot was used as a test piece for measuring the amount of acetaldehyde released.

[0030] The test specimen and 4 L of nitrogen were placed in a Tedra bag and sealed. The bag was left in a thermostatic bath at 65 ° C for 2 hours. Then, the bag was immediately connected to a 2,4-dinitrophenylhydrazine (DNPH) cartridge via a silicon tube, and the entire amount of gas in the bag was sucked into the DNPH cartridge using a pump. The components collected in the DNPH cartridge were extracted with a specified amount (3 to 6 mL) of acetonitrile. The extracted components were analyzed by high performance liquid chromatography (HPLC) (Shimadzu Corporation Nexera) to determine the amount of aldehyde (μg). The HPLC was performed using a reversed phase column (GL Sciences Inc. INERTSIL ODS-80) at a detection wavelength of 360 nm and a column temperature of 40 ° C. The results are shown in Table 1.

[0031] [Table 1]

[0032] The results shown in Table 1 indicate that there is a correlation between the amount of acetaldehyde released from the sample and the amount of faint luminescence from the sample after removing the inhibitors (see Figure 1). The relationship is y = 7.1 × 10 -5 x-0.11, coefficient of determination R 2 It is therefore understood that the amount of acetaldehyde released from an olefin resin containing an inhibitory component can be determined based on the amount of weak luminescence from an olefin resin from which the inhibitory component has been removed.

Claims

1. A method for measuring an amount of aldehyde released from an olefin resin containing at least one selected from the group consisting of a black component and talc, comprising: removing at least one selected from the group consisting of the black component and talc from the olefin-based resin to obtain a resin for luminescence measurement; measuring the amount of weak luminescence from the luminescence measuring resin by a chemiluminescence method; determining an amount of aldehyde released from the olefin-based resin based on the amount of weak luminescence; A method comprising:

2. removing at least one selected from the group consisting of the black component and talc from the olefin resin to obtain the resin for luminescence measurement, dissolving the olefin-based resin in a solvent to obtain a solution; removing at least one selected from the group consisting of the black component and talc from the solution; evaporating the solvent in the solution to obtain the resin for luminescence measurement; The method of claim 1 , comprising, in that order:

3. 3. The method of claim 2, wherein removing at least one selected from the group consisting of the black component and talc from the solution comprises filtering the solution.

4. The method according to any one of claims 1 to 3, wherein the olefin-based resin is a polypropylene-based resin.

5. The method according to any one of claims 1 to 3, wherein the aldehyde is acetaldehyde.

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