JP2009222477A - Measuring method of residual fluocarbon gas in foam - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for measuring a fluorocarbon gas in foam. <P>SOLUTION: The method for measuring the fluorocarbon gas in polyurethane foam is composed of a first process (1) for scattering a predetermined amount of the fluorocarbon gas into a hermetically sealed container and measuring the concentration of the fluorocarbon gas in the hermetically sealed container for form a calibration curve, a second process (2) for grinding the polyurethane foam in the hermetically sealed container to scatter the fluorocarbon gas remaining in the polyurethane foam and a third process (3) for mixing and stirring the inside of the hermetically sealed container to draw out the gas in the hermetically sealed container and measuring the concentration of the fluorocarbon gas by gas chromatography to calculate the residual amount of the fluorocarbon gas in the polyurethane foam from the calibration curve formed in the first process. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for measuring the amount of chlorofluorocarbon gas remaining in a rigid polyurethane foam (cell), and can also be applied to the measurement of the amount of chlorofluorocarbon remaining in foamed plastics such as extruded polystyrene foam.

  When producing a polyurethane foam such as a rigid polyurethane foam, a freon gas-based foaming agent is used as a foaming agent. Fluorocarbons and chlorofluorocarbons used as the main blowing agents have problems such as ozone layer destruction, and hydrofluorocarbons (HFCs) that do not destroy the ozone layer are the next generation blowing agents that can replace them. Although it is listed as a candidate, on the other hand, it has a problem of strong global warming. For these reasons, it is important to grasp the amount of the chlorofluorocarbon-based foaming agent remaining in the polyurethane foam from the viewpoint of the environment and the recycling process.

As a prior art, Patent Documents 1 and 2 are disclosed as a method for recovering the chlorofluorocarbon gas remaining in the polyurethane foam.

JP 2001-170936 A JP-A-2005-306776

  However, this technique cannot accurately determine the amount of chlorofluorocarbon in the polyurethane foam, and there is a problem that chlorofluorocarbon gas remains in the independently foamed cell and a certain amount of chlorofluorocarbon gas remains in the polyurethane foam. For these reasons, it has been difficult to accurately grasp the amount of chlorofluorocarbon gas remaining in the polyurethane foam. Further, when the polyurethane foam in which the chlorofluorocarbon gas remains is disposed of by pulverization or the like, a large amount of the chlorofluorocarbon gas is scattered, which causes a problem that an appropriate recycling process cannot be performed.

  As a result of intensive studies to achieve these problems, the present invention finds that the amount of CFCs remaining in the polyurethane foam is quantified by pulverizing the polyurethane foam in a sealed container and measuring its air concentration. It came to.

That is, the present invention is as follows.
A method for measuring CFCs in polyurethane foam by the following steps,
(1) A first step of creating a calibration curve by scattering a predetermined amount of chlorofluorocarbon gas in a sealed container and measuring the concentration of chlorofluorocarbon in the sealed container.
(2) a second step of pulverizing the polyurethane foam in a sealed container to disperse the fluorocarbon gas remaining in the polyurethane foam;
(3) Mixing and stirring the inside of the sealed container, extracting the gas in the sealed container, measuring the concentration of Freon gas by gas chromatography, and calculating the amount of Freon gas remaining in the polyurethane foam from the calibration curve created in the first step Process,
A measuring method comprising:

  According to the present invention, it is possible to quantify the amount of chlorofluorocarbon gas remaining in the polyurethane foam. This makes it possible to know in advance the amount of chlorofluorocarbon scattering when recycling polyurethane foam, and the type and amount of sorbent when the chlorofluorocarbon gas is fed into a solid alkali material or other adsorbent and subjected to an adsorption treatment by a chemical reaction. It becomes easy to select.

  The present invention quantifies CFC gas in a polyurethane foam cell by finely pulverizing polyurethane foam in a sealed container to disperse CFC gas and quantifying CFC concentration gas concentration in the sealed container. .

Examples of the fluorocarbon gas that can be measured in the present invention include fluorocarbons and chlorofluorocarbons that may be used as a foaming agent in the production of polyurethane foam.
Examples of the fluorocarbons include 1,1,1,3,3-pentafluoropropane (HFC-245fa), 1,1,1,3,3-pentafluorobutane (HFC-365mfc), 1,1,1, 2-tetrafluoroethane (HFC-134a), 1,1,1,2,3,3-hexafluoropropane, 1,1,1,4,4,4-hexafluorobutane, methyl fluoride, perfluoromethane , Ethyl fluoride, 1,1-difluoroethane, 1,1,1-trifluoroethane (HFC-143a), difluoromethane, perfluoroethane, 2,2-difluoropropane, 1,1,1-trifluoropropane, Perfluoropropane, dichloropropane, difluoropropane, perfluorobutane, perfluorocyclobutane, 1,1,1,2,3,3,3 heptafluoropro Emissions (HFC-227ea), pentafluoroethane (HFC-125), 1,1- difluoroethane (HFC-152a), and the like.
The chlorofluorocarbons include 1,1-dichloro-1-fluoroethane (HCFC-141b), 1-chloro-1,1-difluoroethane (HCFC-142b), 1,1-dichloro-2,2,2-tri Fluoroethane (HCHC-123), 1-chloro-1,2,2,2-tetrafluoroethane (HCFC-124), trichloromonofluoromethane (CFC-11), dichlorodifluoromethane (CFC-12), trichloro Examples include trifluoroethane (CFC-113), 1,1,1-trifluoroethane, pentafluoroethane, dichlorotetrafluoroethane (CFC-114), chloroheptafluoropropane, and dichlorohexafluoropropane.

Examples of the polyurethane foam that can be analyzed in the present invention include rigid polyurethane foam that is manufactured using the above-mentioned CFCs and is used as a heat insulating material for refrigerators and houses.

<Preparation: Qualitative properties of CFCs in polyurethane foam>
In order to quantify the chlorofluorocarbon remaining in the polyurethane foam, first, it is necessary to qualify the type of chlorofluorocarbon contained in the polyurethane foam.
As a qualitative method, polyurethane foam is put in a plastic bag or the like and pulverized by hand, and then the gas in the bag is sampled and mass spectrometry (a mass spectrometer sold by each manufacturer can be used. There is no particular limitation. In addition, a method of performing qualitative analysis of CFCs by performing the GC section in accordance with the GC measurement conditions described later). In addition, extraction with an organic solvent and sampling, or insertion of a gas tight syringe directly into a polyurethane foam to sample chlorofluorocarbon, and then qualitative analysis of chlorofluorocarbon with a mass spectrometer may be mentioned.

<First step: Calibration curve creation step>
First, a predetermined amount of chlorofluorocarbon gas determined by qualitative analysis is scattered in a sealed container. Thereafter, the chlorofluorocarbon gas in the sealed container is sampled and injected into gas chromatography (hereinafter abbreviated as GC) to measure the peak area.
Thereafter, several samples of different CFC gas concentrations are similarly measured, and a calibration curve is created from the CFC gas concentration in the sealed container and the GC peak area.

Fluorocarbon concentration in sealed container (mg / L) = Amount of chlorofluorocarbon gas (mg) scattered in sealed container / volume of sealed container (L)

y = Ax + B

y: Freon gas concentration in sealed container (mg / L)
x: Peak area of chlorofluorocarbon gas by GC A and B: values obtained by creating a quadratic function from calibration curve sample measurement results

  In the present invention, the GC device to be used is not particularly limited, and a GC device of each manufacturer can be used. As a detector, a thermal conductivity type detector (TCD), a flame ionization detector (FID), an electron capture type detector (ECD), etc. can be used, but a low concentration sample can be measured. A flame ionization detector (FID) is preferred.

As the column used in the present invention, a column using a nonpolar or slightly polar filler is preferably used. Among these, nonpolarity is preferable, and it is particularly preferable to use a filler modified with 100% dimethylpolysiloxane and 50% n-octyl 50% methylpolysiloxane. When a column using a polar packing material is used, Freon gas is adsorbed on the column packing material and tailing or the like occurs at the peak, resulting in a problem that the quantitative accuracy of the Freon gas is lowered.

<Second step: polyurethane foam grinding step>
Next, polyurethane foam and sandpaper or the like as a tool for pulverizing the polyurethane foam are placed in a sealed container. Thereafter, the polyurethane foam is pulverized in a sealed container using sandpaper or the like to disperse the chlorofluorocarbon gas remaining in the cell.

  The sealed container used in the present invention may be any container that can work in the container while maintaining a sealed state and can sample the gas in the container. Among them, it is preferable to use a highly airtight one such as a glove box in that accurate quantification is possible.

  As the sandpaper used in the present invention, the number 10 to 200 is preferable because it is suitable for finely pulverizing polyurethane foam, and the number 20 to 100 is most preferable. If it is 10 or less, the particle size of the polyurethane foam after pulverization will increase, leaving undestructed cells. If it is 200 or more, sandpaper will be clogged and it will be difficult to pulverize the polyurethane foam. Become.

As the size of the foam particles after pulverization, the diameter is preferably 600 μm or less, and most preferably 300 μm or less. If it exceeds 600 μm, the foam cells are not destroyed and chlorofluorocarbon remaining in the crushed foam may be present, which makes it difficult to perform accurate quantification.

<Third step: Residual CFC measurement step>
After pulverizing the polyurethane foam, the atmosphere in the sealed container is stirred by hand and mixed and stirred to make it uniform. Thereafter, 0.1 to 1.0 cc of the gas in the container is sampled from the sampling port of the sealed container, and the peak area of the Freon gas is obtained by GC measurement.
Thereafter, the concentration of Freon gas in the sealed container is obtained from the calibration curve and the peak area created in the first step, and the amount of scattered Freon gas is calculated.

<Qualitative analysis>
The rigid polyurethane foam A (unknown sample) taken out from the heat insulating material of the house was used as the analysis sample of the example. A part of the rigid polyurethane foam A was put in a commercially available plastic bag and easily pulverized by hand. Thereafter, the sample was left for about 30 minutes, and the gas inside the plastic bag was sampled by 1 cc with a gas tight syringe and subjected to mass spectrometry under the following conditions. As a result, it was found that the chlorofluorocarbon gas contained in the rigid polyurethane foam A was “HCFC-141b”.

(Mass spectrometric conditions)
GC device: GC-2010 (manufactured by Shimadzu Corporation)
Mass spectrometer: GCMS-2010 QP2010 (manufactured by Shimadzu Corporation)
Carrier gas: helium column: NB-1 (film thickness: 0.40 μm, length: 60 m, inner diameter: 0.25 mm ID, 100% dimethyl-polysiloxane modification, manufactured by GL Science)
Column temperature: After temperature adjustment at 35 ° C. (12 min), the temperature is raised at 5 ° C./min to 150 ° C. Heating vaporization chamber: SPL; 180 ° C., linear velocity; 20 cm seconds, split ratio = 5
Detector: FID, 180 ° C
GC injection amount: 0.3cc (gas tight syringe)

<First step>
(Adjustment example 1)
First, in a laboratory controlled at 25 ° C., the glove box (volume: 97.2 L, “AS-600P” manufactured by AS ONE) is purged with nitrogen for 5 minutes to create a nitrogen atmosphere in the sealed container. .
Next, 500 mg of HCFC-141b found by qualitative analysis was weighed into a sealable sample container (22 mL headspace vial, manufactured by PerkinElmer), placed in a glove box, and then gloved while purging with nitrogen again. Seal the box. Then open the sample container to disperse HCFC-141b, stir the atmosphere inside the glove box to make the atmosphere uniform, and then insert a gas tight syringe (capacity: 3.0 cc, manufacturer: Hamilton) from the sampling port. After the inside was pumped and replaced five times, 1.0 cc gas was collected and 0.3 cc was injected into the GC to determine the peak area (S1).

(Adjustment examples 2 to 6)
In the same manner as in S1, calibration curve samples having different concentrations were prepared according to Table 1, and peak areas were determined by GC (S2 to S6). Table 1 shows values obtained by calculating the peak areas obtained in S1 to S6 and the concentration of HCFC-141b in the glove box from the following equations.

HCFC-141b concentration in the glove box (mg / L)
= HFC-141b (mg) /97.2 (L)

A calibration curve was prepared from a graph in which the horizontal axis represents the GC peak area <x> and the vertical axis represents the concentration <y (mg / L)> of HCFC-141b in the glove box. The calibration curve used in the present invention is shown below.
Calibration curve: y = 7.0 × 10 ⁻⁶ x−0.0341

The GC measurement conditions performed this time are as follows.
GC device: GC-2010 (manufactured by Shimadzu Corporation)
Carrier gas: helium column: NB-1 (film thickness: 0.40 μm, length: 60 m, inner diameter: 0.25 mm ID, 100% dimethyl-polysiloxane modification, manufactured by GL Science)
Column temperature: After temperature adjustment at 35 ° C. (12 min), the temperature is raised at 5 ° C./min and heated to 150 ° C. Vaporization chamber: SPL; 180 ° C., linear velocity;
Detector: FID, 180 ° C
GC injection amount: 0.3cc (gas tight syringe)

<Second step>
Example 1
A sample (a1) was cut out from rigid polyurethane foam A molded using HCFC-141b as a foaming agent to 49.8 mm × 49.8 mm × 100.2 mm, put into a glove box together with sandpaper, and purged with nitrogen .
Next, the hard polyurethane foam was slowly pulverized with sandpaper (No. 40, Trusco sheet paper, “GBS-40” manufactured by TRUSCO) to sufficiently scatter the HCFC-141b inside the foam.

<Third step>
After pulverizing the rigid polyurethane foam, the atmosphere in the glove box was sufficiently stirred to make it uniform. Thereafter, a gas tight syringe was inserted from the sampling port and the inside was pumped and replaced five times. Then, 1.0 cc gas was sampled and 0.3 cc was injected into the GC to determine the peak area.

(Examples 2 and 3)
Similarly to Example 1, samples (a2) and (a3) were cut out from the rigid polyurethane foam A, and Freon gas was measured. The results are listed in Table 2.

Examples 1 to 3 in which the same sample was measured showed almost the same analytical value, and the amount of HCFC-141b remaining in the rigid polyurethane foam A was about 89.6 ml (average value of Examples 1 to 3). It turns out that.

Claims (1)

A method for measuring CFCs in polyurethane foam by the following steps,
(1) A first step of creating a calibration curve by scattering a predetermined amount of chlorofluorocarbon gas in a sealed container and measuring the concentration of chlorofluorocarbon in the sealed container.
(2) a second step of pulverizing the polyurethane foam in a sealed container to disperse the fluorocarbon gas remaining in the polyurethane foam;
(3) Mixing and stirring the inside of the sealed container, extracting the gas in the sealed container, measuring the concentration of Freon gas by gas chromatography, and calculating the amount of Freon gas remaining in the polyurethane foam from the calibration curve created in the first step Process,
A measuring method comprising: