Method for testing harmful volatile matters of interior trim assembly of passenger car
阅读说明：本技术 一种乘用车内饰总成有害挥发物测试方法 (Method for testing harmful volatile matters of interior trim assembly of passenger car ) 是由 顾文时 于 2020-04-23 设计创作，主要内容包括：本发明公开了一种乘用车内饰总成有害挥发物测试方法,所述测试方法将一个某具体类型的车内饰总成装入采样袋,并配备同规格空白采样袋,通过加热使有害挥发物质从待检测的吸附物体中脱离出来,通过TENAX采样管采集苯类物质,并通过热解吸系统提取TENAX采样管内的苯类物质,导入气体色谱-质谱仪,通过苯类物质分析曲线获得各苯类物质的定量值,通过DNPH采样管采集醛酮类物质,并通过乙腈洗脱DNPH采样管制成醛酮类物质试剂,导入高效液相色谱仪-二极管阵列检测器,通过醛酮类物质分析曲线获得各醛酮类物质的定量值,最终计算获得个有害挥发物质浓度。本发明通过检测各车内饰总成中挥发出有害物质浓度,进而锁定不合格车内饰总成,实现有针对性的改进。(The invention discloses a method for testing harmful volatile matters of a passenger car interior assembly, which comprises the steps of loading a specific type of car interior assembly into a sampling bag, preparing a blank sampling bag with the same specification, heating to separate harmful volatile matters from an adsorption object to be tested, collecting benzene substances through a TENAX sampling tube, extracting the benzene substances in the TENAX sampling tube through a thermal desorption system, introducing into a gas chromatograph-mass spectrometer, obtaining quantitative values of the benzene substances through a benzene substance analysis curve, collecting aldehyde and ketone substances through a DNPH sampling tube, preparing an aldehyde and ketone substance reagent through an acetonitrile elution DNPH sampling tube, introducing into a high performance liquid chromatograph-diode array detector, obtaining the quantitative values of the aldehyde and ketone substances through the aldehyde and ketone substance analysis curve, and finally calculating to obtain the concentration of the harmful volatile matters. According to the invention, the concentration of harmful substances volatilized from each interior trim assembly is detected, so that unqualified interior trim assemblies are locked, and targeted improvement is realized.)
1. A method for testing harmful volatile matters in an interior trim assembly of a passenger car is characterized by comprising the following steps:
the test method comprises the following steps:
s1: selecting qualified Tedlar sampling bags with the specification of 2000 liters through leak detection and aging tests;
s2: loading an interior trim assembly sample into a sampling bag, preparing a blank sampling bag with the same specification, respectively filling 1000-liter high-purity nitrogen into the interior trim assembly sample sampling bag and the blank sampling bag after the interior trim assembly sample sampling bag and the blank sampling bag are replaced by the high-purity nitrogen, heating, volatilizing harmful substances in the interior trim assembly sample sampling bag and the blank sampling bag, respectively collecting benzene substances in harmful volatile substance mixed gas in the interior trim assembly sample sampling bag and the blank sampling bag by using a TENAX sampling tube at preset sampling flow rate and sampling time, respectively collecting aldehyde and ketone substances in the harmful volatile substance mixed gas in the interior trim assembly sample sampling bag and the blank sampling bag by using a DNPH sampling tube at preset sampling flow rate and sampling time, and hermetically storing the collected TENAX sampling tube and the collected DNPH sampling tube;
s3: introducing the gas mixed with benzene substances, which is heated and separated from the TENAX sampling tube by the thermal desorption system, into a gas chromatography-mass spectrometer, performing qualitative and quantitative analysis by an external standard method, generating and outputting a corresponding benzene substance analysis curve, and obtaining quantitative values of the benzene substances in the interior trim assembly sample sampling bag and the blank sampling bag; reacting aldehyde ketone substances in gas adsorbed by the DNPH sampling tube with 2.4-dinitrophenylhydrazine, eluting products obtained after the aldehyde ketone substances in the DNPH sampling tube react with the 2.4-dinitrophenylhydrazine through acetonitrile, qualitatively and quantitatively analyzing the reagent by using a high performance liquid chromatograph-diode array detector through an external standard method, generating and outputting corresponding aldehyde ketone substance analysis curves, and obtaining quantitative values of the aldehyde ketone substances in the interior trim assembly sample sampling bag and the blank sampling bag;
s4: the concentration of harmful volatile substances is obtained by calculation according to the following formula (1):
CVOC＝(A-BL)×1000/(V×T)·················(1)
in the above formula (1):
CVOCconcentration of harmful volatile substances, unit: microgram/cubic meter;
a is the quantitative value of harmful volatile substance in the interior trim assembly sample sampling bag, unit: nanogram;
b L is the quantitative value of harmful volatile substance in the blank sampling bag, unit is nanogram;
v is the sampling flow rate in units of: ml/min;
t is the sampling time, unit: and (3) minutes.
2. The method for testing harmful volatile matters in the interior trim assembly of the passenger car as claimed in claim 1, wherein the method comprises the following steps:
the interior trim assembly samples to be tested included: the car body comprises an instrument panel assembly, a sub-instrument panel assembly, a door guard plate assembly, a door substrate assembly, a front row seat assembly, a rear row seat assembly, a seat cover assembly, a seat foaming assembly, a ceiling assembly, a carriage main carpet assembly, a carriage floor sound insulation pad, a trunk cover guard surface/back door guard plate assembly, a trunk left and right guard surface assembly, a trunk carpet assembly, a rear wrapping frame assembly, an upright post decoration assembly, a front wall inner sound insulation pad assembly, a steering wheel, a door and window sealing strip assembly, an air conditioner box assembly, an instrument panel wiring harness assembly, a sun visor assembly and a skylight sun visor assembly.
3. The method for testing harmful volatile matters in the interior trim assembly of the passenger car as claimed in claim 1, wherein the method comprises the following steps:
the benzene substances comprise: benzene, toluene, ethylbenzene, xylene, and styrene;
the aldehyde ketone substances comprise: formaldehyde, acetaldehyde and acrolein.
4. The method for testing harmful volatile matters in the interior trim assembly of the passenger car as claimed in claim 1, wherein the method comprises the following steps:
in step S1, the leak detection and aging process of the sampling bag is as follows:
s1.1 sampling bag leak detection
Pumping air in the sampling bag until the sampling bag is in a vacuum shriveled state, sealing the sampling bag, observing whether air enters the sampling bag after the sampling bag is placed for a preset time, if no air enters the sampling bag, detecting the leakage of the sampling bag to be qualified, and if air enters the sampling bag, detecting the leakage of the sampling bag to be unqualified;
s1.2 sampling bag aging detection
Turn out the sampling bag inside, through heating to predetermineeing the temperature to the sampling bag inner face to keep for a certain time, realize fully ageing the back to the sampling bag inner face, turn back the sampling bag inner face to clean the sampling bag inner face, gather the harmful substance concentration in the ageing back sampling bag through the mode of dashing into nitrogen gas and heating at last, and compare with harmful substance concentration limit value, the blank value limit value of sampling bag is specifically as following one:
watch 1
5. The method for testing harmful volatile matters in the interior trim assembly of the passenger car as claimed in claim 1, wherein the method comprises the following steps:
in the step S2, before 1000 liters of nitrogen gas is respectively filled into the interior trim assembly sample sampling bag and the blank sampling bag, the interior trim assembly sample sampling bag and the blank sampling bag need to be cleaned, and the cleaning process is as follows: and respectively filling 1000 liters of nitrogen into the interior trim assembly sample sampling bag and the blank sampling bag, then pumping out the nitrogen, and repeatedly filling and pumping out the nitrogen for three times according to the same operation standard.
6. The method for testing harmful volatile matters in the interior trim assembly of the passenger car as claimed in claim 1, wherein the method comprises the following steps:
in the step S2, in the process of heating to volatilize harmful substances in the interior trim assembly sample sampling bag and the blank sampling bag, the heating temperature is 65 ℃, the heating time is 2 hours, and the interior trim assembly sample sampling bag is kneaded before the heating is finished, so that the harmful volatile substances separated out from the interior trim assembly sample sampling bag are uniformly distributed in the sampling bag.
7. The method for testing harmful volatile matters in the interior trim assembly of the passenger car as claimed in claim 1, wherein the method comprises the following steps:
in step S2, first, 100 ml of the harmful volatile substance mixed gas is led out from the interior assembly sample bag and the blank sample bag, and then the harmful volatile substance mixed gas is collected through the TENAX sample tube and the DNPH sample tube;
respectively collecting 3 liters of harmful volatile substance mixed gas in an interior trim assembly sample sampling bag and a blank sampling bag by using a TENAX sampling pipe at a sampling rate of 0.2 liter/minute;
at a sampling rate of 0.8 l/min, 12 l of mixed noxious volatile matter gas was collected from the interior trim assembly sample bag and the blank sample bag, respectively, using DNPH sampling tubes.
8. The method for testing harmful volatile matters in the interior trim assembly of the passenger car as claimed in claim 1, wherein the method comprises the following steps:
in step S3, the setting conditions of the thermal desorption system are specifically: the dry blowing time is 3 minutes, the desorption time is 10 minutes, the desorption temperature is 300 ℃, the cold trap temperature is minus 10 ℃, the temperature is kept for 3 minutes, and the outlet split ratio is 50: 1;
the set conditions of the gas chromatography-mass spectrometer are specifically that a chromatographic column Ultra2 is 50 m, × 320 m, × 0.52 m and 3926.52 m, the flow rate of the column is 1 ml/min, the temperature of a column box is kept at 40 ℃ for 3 min, then the temperature is increased to 90 ℃ at the heating rate of 10 ℃/min, the temperature of 90 ℃ is kept for 5 min, then the temperature is increased to 280 ℃ at the heating rate of 10 ℃/min, the temperature of 280 ℃ is kept for 6 min, the temperature of an ion source is 230 ℃, and the mass number is 35 amu-450 amu.
The set conditions of the high performance liquid chromatograph are specifically that a chromatographic column Syncronics C18 is 4.6 mm × 250 mm, a column box is 35 ℃, a detector DAD is arranged, a mobile phase is acetonitrile or water, the flow rate is 0.5 ml/min, and the sample injection amount is 15 microliters.
9. The method for testing harmful volatile matters in the interior trim assembly of a passenger car as claimed in claim 1 or 8, wherein:
when the volatile organic compound emission amount of the interior assembly sample is large, the flow dividing ratio of the outlet of the thermal desorption system is adjusted to reduce the sample inlet amount of the gas chromatography-mass spectrometer and increase the high concentration point of the standard reagent;
when analyzing aldehyde ketone substances through a high performance liquid chromatograph, for a reagent containing aldehyde ketone substances with high concentration, the reagent is diluted so as to reduce the concentration of the reagent to be within the range of an analysis curve.
10. The method for testing harmful volatile matters in the interior trim assembly of the passenger car as claimed in claim 1, wherein the method comprises the following steps:
according to the step S1-the step S4, the concentration of harmful volatile matters volatilized by each interior trim assembly is respectively obtained, the VOC contribution degree of each interior trim assembly to the whole vehicle is calculated according to the concentration of various harmful volatile matters emitted by each interior trim assembly, and then unqualified interior trim assemblies are locked, and the unqualified interior trim assemblies are improved in a targeted manner.
Technical Field
The invention belongs to the technical field of detection of toxic and harmful volatile matters of non-metal parts of automobiles, and particularly relates to a method for testing harmful volatile matters of an interior trim assembly of a passenger car.
Background
With the rapid development of national economy, the living standard of people is constantly promoted, and passenger cars have become indispensable vehicles for people to go out. With the increasing popularity of passenger vehicles, the public has increasingly high demands on the dynamics, fuel economy, braking performance, steering stability, and ride comfort of passenger vehicles.
In recent years, with the increasing environmental awareness of the public, namely the increasing awareness of self-protection, the problem of pollution of the internal space of a passenger car is more and more exposed to the public, which begins as early as 2013, and the passenger car is complained continuously, and vehicles including a plurality of international high-grade vehicle systems have poor air quality in the car, contain sharp nose and eyes in the car and cause uncomfortable gas in the throat, so that children are used as high-frequency users of family passenger cars, and the health of the children is seriously threatened. Therefore, the public attention on toxic and harmful volatile matters in the interior of passenger cars is higher and higher, and the concern is also a problem which is heavily considered when people buy cars.
The poisonous and harmful volatile matters in the vehicle are mainly from nonmetal assemblies, including instrument panel assemblies, door guard plate assemblies, steering wheel assemblies, seat assemblies and the like, and the poisonous and harmful organic matters or the aldehydes and ketones emitted by the assemblies seriously pollute the environment in the vehicle and threaten the health of drivers and passengers.
At present, the state sets up an industry standard for environmental protection, and for the quality of the air of the whole automobile in the automobile industry, the state sets up an industry standard of HJ/T400-2007 'method for sampling and measuring volatile organic compounds and aldehydes and ketones in the automobile', and the industry standard is applicable to: the method comprises the steps of measuring the settings of sampling points of volatile organic compounds and aldehyde and ketone substances in the passenger compartment of the motor vehicle, the technical requirements of sampling environmental conditions, sampling methods and equipment, corresponding measuring methods and equipment, data processing, quality assurance and the like. According to the application range, the HJ/T400-2007 industrial standard is used for detecting the content of toxic and harmful substances volatilized into the interior space of the vehicle, but the content of the toxic and harmful substances of each assembly in the vehicle cannot be determined, and whether the content is a main source causing the standard exceeding of the indexes of the harmful substances in the vehicle or not can be determined; once the condition that the vehicle is unqualified occurs, even if the condition that certain harmful substance or certain kinds of harmful substances exceed standards can be detected, the condition that the corresponding harmful substance comes from which kind of interior assembly or certain kinds of interior assemblies in the vehicle cannot be judged. In addition, the contribution value of each assembly part to toxic and harmful substances in the vehicle cannot be determined.
In addition, even if the same assembly is used, the content of toxic and harmful substances can be significantly different due to different suppliers or different manufacturing and processing links.
In summary, according to the prior art, whether the air quality in the vehicle interior is qualified or not can be accurately detected, and the type of specific unqualified substances can also be detected, but the source of toxic and harmful substances cannot be locked, so that corresponding responsibility tracing or improvement measures cannot be taken in a targeted manner, and the problem of pollution to the air environment in the vehicle cannot be fundamentally solved.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a method for testing harmful volatile substances in a passenger car interior trim assembly, which can be used for quickly and accurately detecting the concentration of different types of toxic and harmful substances volatilized from the passenger car interior trim assembly and indicating the direction for fundamentally solving the problem of air environmental pollution in a passenger car. The technical scheme of the invention is as follows by combining the attached drawings of the specification:
a method for testing harmful volatile matters of an interior trim assembly of a passenger car comprises the following steps:
s1: selecting qualified Tedlar sampling bags with the specification of 2000 liters through leak detection and aging tests;
s2: loading an interior trim assembly sample into a sampling bag, preparing a blank sampling bag with the same specification, respectively filling 1000-liter high-purity nitrogen into the interior trim assembly sample sampling bag and the blank sampling bag after the interior trim assembly sample sampling bag and the blank sampling bag are replaced by the high-purity nitrogen, heating, volatilizing harmful substances in the interior trim assembly sample sampling bag and the blank sampling bag, respectively collecting benzene substances in harmful volatile substance mixed gas in the interior trim assembly sample sampling bag and the blank sampling bag by using a TENAX sampling tube at preset sampling flow rate and sampling time, respectively collecting aldehyde and ketone substances in the harmful volatile substance mixed gas in the interior trim assembly sample sampling bag and the blank sampling bag by using a DNPH sampling tube at preset sampling flow rate and sampling time, and hermetically storing the collected TENAX sampling tube and the collected DNPH sampling tube;
s3: introducing the gas mixed with benzene substances, which is heated and separated from the TENAX sampling tube by the thermal desorption system, into a gas chromatography-mass spectrometer, performing qualitative and quantitative analysis by an external standard method, generating and outputting a corresponding benzene substance analysis curve, and obtaining quantitative values of the benzene substances in the interior trim assembly sample sampling bag and the blank sampling bag; reacting aldehyde ketone substances in gas adsorbed by the DNPH sampling tube with 2.4-dinitrophenylhydrazine, eluting products obtained after the aldehyde ketone substances in the DNPH sampling tube react with the 2.4-dinitrophenylhydrazine through acetonitrile, qualitatively and quantitatively analyzing the reagent by using a high performance liquid chromatograph-diode array detector through an external standard method, generating and outputting corresponding aldehyde ketone substance analysis curves, and obtaining quantitative values of the aldehyde ketone substances in the interior trim assembly sample sampling bag and the blank sampling bag;
s4: the concentration of harmful volatile substances is obtained by calculation according to the following formula (1):
CVOC＝(A-BL)×1000/(V×T)·················(1)
in the above formula (1):
CVOCconcentration of harmful volatile substances, unit: microgram/cubic meter;
a is the quantitative value of harmful volatile substance in the interior trim assembly sample sampling bag, unit: nanogram;
b L is the quantitative value of harmful volatile substance in the blank sampling bag, unit is nanogram;
v is the sampling flow rate in units of: ml/min;
t is the sampling time, unit: and (3) minutes.
Further, the interior trim assembly samples to be tested comprise: the car body comprises an instrument panel assembly, a sub-instrument panel assembly, a door guard plate assembly, a door substrate assembly, a front row seat assembly, a rear row seat assembly, a seat cover assembly, a seat foaming assembly, a ceiling assembly, a carriage main carpet assembly, a carriage floor sound insulation pad, a trunk cover guard surface/back door guard plate assembly, a trunk left and right guard surface assembly, a trunk carpet assembly, a rear wrapping frame assembly, an upright post decoration assembly, a front wall inner sound insulation pad assembly, a steering wheel, a door and window sealing strip assembly, an air conditioner box assembly, an instrument panel wiring harness assembly, a sun visor assembly and a skylight sun visor assembly.
Further, the benzene-based substances include: benzene, toluene, ethylbenzene, xylene, and styrene;
the aldehyde ketone substances comprise: formaldehyde, acetaldehyde and acrolein.
Further, in step S1, the leak detection and aging process of the sampling bag is as follows:
s1.1 sampling bag leak detection
Pumping air in the sampling bag until the sampling bag is in a vacuum shriveled state, sealing the sampling bag, observing whether air enters the sampling bag after the sampling bag is placed for a preset time, if no air enters the sampling bag, detecting the leakage of the sampling bag to be qualified, and if air enters the sampling bag, detecting the leakage of the sampling bag to be unqualified;
s1.2 sampling bag aging detection
Turn out the sampling bag inside, through heating to predetermineeing the temperature to the sampling bag inner face to keep for a certain time, realize fully ageing the back to the sampling bag inner face, turn back the sampling bag inner face to clean the sampling bag inner face, gather the harmful substance concentration in the ageing back sampling bag through the mode of dashing into nitrogen gas and heating at last, and compare with harmful substance concentration limit value, the blank value limit value of sampling bag is specifically as following one:
watch 1
Composition (I)
Sampling bag blank value limit (microgram/cubic meter)
Formaldehyde (I)
<10
Acetaldehyde
<10
Acrolein
<10
Benzene and its derivatives
<4
Toluene
<5
Xylene
<12
Ethylbenzene production
<4
Styrene (meth) acrylic acid ester
<4
Further, in step S2, before filling 1000 liters of nitrogen gas into the interior trim assembly sample bag and the blank sampling bag, the interior trim assembly sample bag and the blank sampling bag need to be cleaned, and the cleaning process is as follows: and respectively filling 1000 liters of nitrogen into the interior trim assembly sample sampling bag and the blank sampling bag, then pumping out the nitrogen, and repeatedly filling and pumping out the nitrogen for three times according to the same operation standard.
Further, in the step S2, in the process of heating to volatilize harmful substances in the interior trim assembly sample sampling bag and the blank sampling bag, the heating temperature is 65 ℃, the heating time is 2 hours, and the interior trim assembly sample sampling bag is kneaded before the heating is finished, so that the harmful volatilized substances separated out from the interior trim assembly sample sampling bag are uniformly distributed in the sampling bag.
Further, in step S2, first, 100 ml of the harmful volatile substance mixed gas is led out from the interior trim assembly sample bag and the blank sample bag, and then the harmful volatile substance mixed gas is collected through the TENAX sample tube and the DNPH sample tube;
respectively collecting 3 liters of harmful volatile substance mixed gas in an interior trim assembly sample sampling bag and a blank sampling bag by using a TENAX sampling pipe at a sampling rate of 0.2 liter/minute;
at a sampling rate of 0.8 l/min, 12 l of mixed noxious volatile matter gas was collected from the interior trim assembly sample bag and the blank sample bag, respectively, using DNPH sampling tubes.
Further, in step S3, the setting conditions of the thermal desorption system specifically include: the dry blowing time is 3 minutes, the desorption time is 10 minutes, the desorption temperature is 300 ℃, the cold trap temperature is minus 10 ℃, the temperature is kept for 3 minutes, and the outlet split ratio is 50: 1;
the set conditions of the gas chromatography-mass spectrometer are specifically that a chromatographic column Ultra2 is 50 m, × 320 m, × 0.52 m and 3926.52 m, the flow rate of the column is 1 ml/min, the temperature of a column box is kept at 40 ℃ for 3 min, then the temperature is increased to 90 ℃ at the heating rate of 10 ℃/min, the temperature of 90 ℃ is kept for 5 min, then the temperature is increased to 280 ℃ at the heating rate of 10 ℃/min, the temperature of 280 ℃ is kept for 6 min, the temperature of an ion source is 230 ℃, and the mass number is 35 amu-450 amu.
The set conditions of the high performance liquid chromatograph are specifically that a chromatographic column Syncronics C18 is 4.6 mm × 250 mm, a column box is 35 ℃, a detector DAD is arranged, a mobile phase is acetonitrile or water, the flow rate is 0.5 ml/min, and the sample injection amount is 15 microliters.
Further, when the volatile organic compound emission amount of the interior assembly sample is large in analyzing the benzene substances through the gas chromatography-mass spectrometer, the flow ratio of the outlet of the thermal desorption system is adjusted to reduce the sample introduction amount of the gas chromatography-mass spectrometer and increase the high concentration point of the standard reagent;
when analyzing aldehyde ketone substances through a high performance liquid chromatograph, for a reagent containing aldehyde ketone substances with high concentration, the reagent is diluted so as to reduce the concentration of the reagent to be within the range of an analysis curve.
Further, according to the step S1 — the step S4, the concentrations of the harmful volatile matters volatilized by the interior trim assemblies are respectively obtained, and the VOC contribution degree of each interior trim assembly to the whole vehicle is calculated according to the concentrations of various harmful volatile matters emitted by the interior trim assemblies, so that the unqualified interior trim assemblies are locked, and the unqualified interior trim assemblies are improved in a targeted manner.
Compared with the prior art, the invention has the beneficial effects that:
the method for testing the harmful volatile matters of the interior trim assembly of the passenger car can realize the concentration of the harmful volatile matters of different types released by the interior trim assemblies of different types, can accurately lock the source of toxic and harmful substances causing the air environment of the whole car not to reach the standard, and can take corresponding accountability or improvement measures in a targeted manner, thereby fundamentally solving the problem of air environment pollution in the passenger car;
drawings
FIG. 1 is a schematic structural view of a testing and sampling device of the method for testing harmful volatile substances in the interior trim assembly of a passenger car.
FIG. 2 is a schematic diagram of an analysis curve of benzene substances generated and output by a gas chromatography-mass spectrometer in the testing method of the invention;
FIG. 3 is a schematic diagram of an analytical curve of aldehydes and ketones generated and outputted by a high performance liquid chromatograph-diode array detector in the testing method of the present invention;
in the figure:
1-a sampling bin, 2-a sampling bag, 3-an interior trim assembly sample,
4-valves, 5-TENAX trap, 6-DNPH trap,
7-Teflon tube, 8-sampling pump, 9-flowmeter.
Detailed Description
For clearly and completely describing the technical scheme and the specific working process thereof, the specific implementation mode of the invention is as follows by combining the attached drawings of the specification:
before the description of the embodiments of the present invention, it should be noted that:
1. in the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
2. In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.
3. In particular descriptions of the present specification, references to the description of the term "one embodiment," "some embodiments," "an example," "a particular example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
The invention discloses a method for testing harmful volatile matters of a passenger car interior assembly, which adopts a bag type method, a specific type of car interior assembly is put into a Tedlar bag with the specification of 2000 liters, a thermal desorption method is adopted, harmful volatile matters including benzene series and aldehyde ketone substances are separated from an adsorption object to be tested by heating, and then the concentration of the harmful volatile matters is detected. The test method comprises the following specific steps:
s1: selecting qualified sampling bags;
according to the testing method, a Tedlar bag is selected as a sampling bag, the Tedlar bag is produced by DuPont and made of a polyvinyl fluoride film, and the resistance and durability of the polyvinyl fluoride film to sunlight, chemical solvents, acid-base corrosion, moisture and oxidation are remarkably improved due to the fact that a fluorocarbon covalent bond in polyvinyl fluoride is far stronger than chemical bonds in other polymers; the surface repulsion of the polyvinyl fluoride film is large, so that dust can be prevented from being polluted, the cleaning and the maintenance are easy, and the polyvinyl fluoride film is not damaged even if the polyvinyl fluoride film is the strongest detergent; from 70 ℃ below zero to 110 ℃, the polyvinyl fluoride film can ensure excellent performance, and the instantaneous temperature peak value can not be damaged even when the temperature peak value reaches 200 ℃; according to the advantages of the characteristics, a Tedlar bag is preferably adopted as the sampling bag in the testing method.
S1.1 sampling bag leak detection
Taking a sampling bag, pumping air in the sampling bag by using a constant-flow air sampling pump until the sampling bag is in a vacuum shriveled state, sealing the sampling bag, standing for 10 minutes, observing whether air enters the sampling bag, if no air enters the sampling bag, detecting the leakage of the sampling bag, and if air enters the sampling bag, detecting the leakage of the sampling bag, and determining that the sampling bag is unqualified;
selecting a sampling bag qualified for leak detection to carry out the next step;
s1.2 sampling bag aging detection
S1.2.1, turning out the inner surface of a sampling bag, putting the sampling bag into an experimental box, and heating the sampling bag for aging at 78-82 ℃ for 10-12 hours;
s1.2.2, opening the door of the experiment box, replacing the air in the experiment box for 30 minutes, namely, exposing the sampling bag in the experiment box in a normal temperature environment for 30 minutes, realizing natural cooling of the sampling bag, then turning the sampling bag 180 degrees, turning the bottom surface of the sampling bag upwards in the step S1.2.1, closing the door of the experiment box, heating again to realize aging treatment, wherein the heating temperature is 78-82 ℃, the heating time is 2-3 hours, and finally, the inner surface of the sampling bag is uniformly aged through the step;
s1.2.3 turning the inner surface of the sampling bag back to the inner side, evacuating the gas in the sampling bag by a diaphragm vacuum pump, filling high-purity nitrogen with the volume of 30-40% of the volume of the sampling bag, pumping out the nitrogen, and repeating the same operation for three times to remove the pollutants attached to the inner wall of the sampling bag by nitrogen cleaning;
s1.2.4 filling 1000L nitrogen gas into the sampling bag, and heating the sampling bag at 65 deg.C for 1 hr 50 min to 2 hr 10 min;
s1.2.5 detecting the concentration of benzene and aldehyde ketone in the sampling bag, wherein the benzene is collected by a TENAX sampling tube, and the benzene comprises: benzene, toluene, ethylbenzene, xylene, and styrene; the aldehyde ketone substances are collected by adopting a DNPH sampling tube, and the aldehyde ketone substances comprise: formaldehyde, acetaldehyde and acrolein;
in this step, the concentration of benzene substances and aldehyde ketone substances in the sampling bag is detected, that is, the blank value of the sampling bag is obtained, whether the sampling bag releases harmful volatile substances in the actual sampling process can be reflected through whether the blank value is qualified, and the accuracy of the detection result of the sample to be detected loaded in the sampling bag is affected, that is, whether the cleanliness of the sampling bag is qualified is detected through the aging detection step, if the blank value of the sampling bag is within the blank value limit value of the sampling bag, the cleanliness of the sampling bag is qualified, if the blank value of the sampling bag exceeds the blank value limit value of the sampling bag, the cleanliness of the sampling bag is unqualified, and the blank value limit values of the sampling bag are specifically as the following table one:
watch 1
Composition (I)
Sampling bag blank value limit (microgram/cubic meter)
Formaldehyde (I)
<10
Acetaldehyde
<10
Acrolein
<10
Benzene and its derivatives
<4
Toluene
<5
Xylene
<12
Ethylbenzene production
<4
Styrene (meth) acrylic acid ester
<4
S1.2.6 selecting the sampling bag with qualified cleanliness to carry out the next step, repeating the steps S1.2.3-S1.2.5 on the sampling bag with unqualified cleanliness, and cleaning the sampling bag again until the cleanliness is qualified or the sampling bag is discarded.
S2: sampling;
s2.1, preparing an interior trim assembly sample sampling bag and a blank sampling bag:
firstly, putting an assembly sample into a sampling bag in a flat mode, enabling the exposed surface of the assembly sample in the air environment of a whole vehicle to face upwards, paying attention to prevent a projection of an assembly part from puncturing the sampling bag, meanwhile, preparing an empty sampling bag with the same specification, namely a blank sampling bag, and then sealing the cut of the sampling bag with the assembly sample and the cut of the blank sampling bag respectively by using a film sealing machine or a sealing strip;
the purpose of adopting the blank sampling bag in the step is to avoid the inaccuracy of the detection result caused by the pollution of the detection equipment or the detection process. That is, under the same operating specification, the harmful substance content in the sampling bag of the assembly sample minus the harmful substance content in the blank sampling bag is the harmful substance content actually released by the assembly sample.
The systematic classification of the assembly samples, the assembly part names and the corresponding sampling bag specifications are detailed in the following table two:
watch two
S2.2 cleaning the sampling bag:
respectively filling 1000 liters of nitrogen into the interior trim assembly sample sampling bag and the blank sampling bag, then extracting the nitrogen, and repeatedly filling and extracting the nitrogen for three times according to the same operation standard so as to clean pollutants attached to the inner walls of the interior trim assembly sample sampling bag and the blank sampling bag by the nitrogen;
s2.3, heating to separate out harmful volatile substances:
respectively filling 1000 liters of nitrogen into the interior trim assembly sample sampling bag and the blank sampling bag again, putting the interior trim assembly sample sampling bag and the blank sampling bag which are filled with the nitrogen into a sealed environment with the temperature of 65 ℃ for heating for 2 hours, and kneading the interior trim assembly sample sampling bag in a constant temperature environment 10 minutes before the heating is finished so as to realize that harmful volatile substances separated out from the interior trim assembly sample sampling bag are uniformly distributed in the sampling bags;
s2.4, collecting harmful volatile substances by a sampling pipe:
under the constant temperature environment, respectively leading out 100 ml of harmful volatile substance mixed gas from an interior trim assembly sample sampling bag and a blank sampling bag, respectively collecting 3 liters of harmful volatile substance mixed gas in the interior trim assembly sample sampling bag and the blank sampling bag by using a TENAX sampling pipe at a sampling rate of 0.2 liter/minute, and respectively collecting 12 liters of harmful volatile substance mixed gas in the interior trim assembly sample sampling bag and the blank sampling bag by using a DNPH sampling pipe at a sampling rate of 0.8 liter/minute;
the mixed gas of the harmful volatile matters is the mixed gas of the harmful volatile matters and nitrogen;
s2.5, saving a sampling tube:
respectively wrapping and sealing the collected TENAX sampling tube and DNPH sampling tube by an aluminum foil or aluminum bag, placing the sealed packets into a zipper plastic bag, and marking;
the TENAX sampling tube is used for collecting benzene substances in harmful volatile matters, and the benzene substances comprise: benzene, toluene, ethylbenzene, xylene, and styrene;
the DNPH sampling tube is used for collecting aldehyde ketone substances in harmful volatile substances, and the aldehyde ketone substances comprise: formaldehyde, acetaldehyde and acrolein;
after the sampling of the TENAX sampling tube and the DNPH sampling tube is finished, quantitative analysis is carried out as soon as possible, if analysis cannot be carried out in time, the TENAX sampling tube and the DNPH sampling tube are stored in a refrigerator to be refrigerated, the refrigerating temperature is 4-10 ℃, and the longest storage life of the TENAX sampling tube and the DNPH sampling tube is one week.
S3: analyzing;
s3.1 the process of benzene substance analysis is as follows:
and (3) performing qualitative and quantitative analysis on benzene substances in the harmful volatile substances collected by the TENAX sampling tube in the step S2.4 by using a gas chromatography-mass spectrometer equipped with a thermal desorption system by adopting an analysis external standard method, wherein:
separating the benzene substances collected by the TENAX sampling tube from the TENAX sampling tube by the thermal desorption system by using a thermal desorption method to form a gas mixed with the benzene substances;
the set conditions of the thermal desorption system are specifically as follows: the dry blowing time is 3 minutes, the desorption time is 10 minutes, the desorption temperature is 300 ℃, the cold trap temperature is minus 10 ℃, the temperature is kept for 3 minutes, and the outlet split ratio is 50: 1;
inputting the gas mixed with benzene substances, which is heated and separated from a TENAX sampling tube in a thermal desorption system, into a gas chromatography-mass spectrometer, wherein the method comprises the following steps: generating and outputting a corresponding benzene substance analysis curve of a benzene substance standard reagent containing benzene, toluene, ethylbenzene, xylene and styrene by a gas chromatography-mass spectrometer, wherein the curve is shown in fig. 2; finally, respectively reading and obtaining quantitative values of benzene, toluene, ethylbenzene, xylene and styrene in the interior trim assembly sample sampling bag and the blank sampling bag according to the corresponding benzene substance analysis curve;
the set conditions of the gas chromatography-mass spectrometer are specifically that a chromatographic column Ultra2 is 50 m, × 320 m, × 0.52 m and 3926.52 m, the flow rate of the column is 1 ml/min, the temperature of a column box is kept at 40 ℃ for 3 min, then the temperature is increased to 90 ℃ at the heating rate of 10 ℃/min, the temperature of 90 ℃ is kept for 5 min, then the temperature is increased to 280 ℃ at the heating rate of 10 ℃/min, and the temperature of 280 ℃ is kept for 6 min, the temperature of an ion source is 230 ℃, and the mass number is 35 amu-450 amu;
for an assembly sample with large volatile organic compound emission, the flow split ratio of the outlet of the thermal desorption system can be adjusted to reduce the sample introduction amount of the gas chromatography-mass spectrometer and increase the high concentration point of the standard reagent for analysis;
s3.2 the analytical process of the aldehyde ketone substances is as follows:
firstly, reacting an aldehyde ketone substance in the gas adsorbed by the DNPH sampling tube in the step S2.4 with 2.4-dinitrophenylhydrazine, wherein the aldehyde ketone substance can be detected in the DNPH sampling tube in advance because the 2.4-dinitrophenylhydrazine and the aldehyde ketone substance can generate a color reaction; then, extracting a proper amount of chromatographic pure acetonitrile by using a glass syringe, connecting the glass syringe to a DNPH sampling tube, slowly extracting to elute the derivative obtained after the reaction of the 2, 4-dinitrophenylhydrazine and the aldehyde ketone substances by using the acetonitrile, and fixing the volume of the eluent as a reagent to a measuring flask or a similar container of 5 ml; finally, extracting 20 microliters of reagent, adopting an aldehyde-ketone-DNPH derivative mixed sample or equivalent manufactured by RADIAN company as an aldehyde and ketone substance standard reagent including formaldehyde, acetaldehyde and acrolein, and carrying out qualitative and quantitative analysis on the aldehyde and ketone substances in the reagent by using an external standard method through a high performance liquid chromatograph-diode array detector to generate and output a corresponding aldehyde and ketone substance analysis curve, as shown in FIG. 3; finally, according to the corresponding aldehyde ketone substance analysis curves, respectively reading and obtaining quantitative values of formaldehyde, acetaldehyde and acrolein in the interior trim assembly sample sampling bag and the blank sampling bag;
the set conditions of the high performance liquid chromatograph are that a chromatographic column Syncronics C18 is 4.6 mm × 250 mm, a column box is 35 ℃, a detector DAD is arranged, a mobile phase is acetonitrile or water, the flow rate is 0.5 ml/min, and the sample injection amount is 15 microliter;
for high concentrations of reagents, the reagents may be diluted to bring the concentration of the reagents down within the analytical curve;
the refrigerated storage period of the reagent eluted and extracted by acetonitrile is one week.
The instruction control of the analysis process of the benzene substances and the aldehyde and ketone substances requires the following table three:
watch III
Under the specified analysis conditions, analyzing all harmful substances with retention time between the retention time of n-hexane (C6) and the retention time of n-hexadecane (C16) on the basis of the area with the minimum area rejection value of 0.01 g of toluene, and confirming the substance concentration corresponding to the peak area by using an analysis curve of toluene according to the response peak area of all harmful substances between the retention time of n-hexane (C6) and the retention time of n-hexadecane (C16) read by an analysis device;
the benzene substance analysis process S3.1 and the aldehyde ketone substance analysis process S3.2 can be performed simultaneously without being sequenced.
S4: calculating;
rounding the quantitative values of benzene, toluene, ethylbenzene, xylene and styrene in the interior assembly sample sampling bag and the blank sampling bag obtained in the step S3 and the quantitative values of formaldehyde, acetaldehyde and acrolein in the interior assembly sample sampling bag and the blank sampling bag obtained, respectively, to three decimal places, and calculating the concentration of the corresponding harmful volatile substance according to the following formula (1);
CVOC＝(A-BL)×1000/(V×T)·················(1)
in the above formula (1):
CVOCis the concentration of the corresponding harmful volatile substance, unit: microgram/cubic meter;
a is the quantitative value of harmful volatile substance in the corresponding interior trim assembly sample sampling bag, unit: nanogram;
b L is the quantitative value of harmful volatile substance in corresponding blank sampling bag, with unit of nanogram;
v is the sampling flow rate in units of: ml/min;
t is the sampling time, unit: and (3) minutes.
The concentrations of benzene, toluene, ethylbenzene, xylene, styrene, formaldehyde, acetaldehyde and acrolein volatilized from the corresponding assembly samples are obtained through calculation in the steps.
The measurement results of the samples of the partial types of assemblies obtained by the above steps are shown in the following table four:
watch four
S5 calculation of TVOC
According to the steps S1 to S4, the interior trim assemblies of the passenger cars in the second car are respectively tested to obtain the concentrations of benzene substances and aldehyde ketone substances volatilized by each interior trim assembly, and according to the analysis of the test results shown in the third car, the VOC contribution degree of each interior trim assembly to the whole car is calculated, so that the interior trim assemblies which are not in environmental protection standard are locked, the unqualified interior trim assemblies are improved in a targeted manner, and the problem that the air environment in the passenger cars is not in standard is finally solved fundamentally.
In the method for testing harmful volatile substances in the interior trim assembly of the passenger car, the structure of the sampling device used in the sampling process is as follows:
as shown in fig. 1, the sampling apparatus includes: sampling bin 1, sampling bag 2, valve 4, TENAX trap 5, DNPH trap 6, Teflon tube 7, sampling pump 8 and flow meter 9.
The sampling bin 1 adopts a constant-temperature drying box; the wall of the sampling bin 1 is provided with a mounting hole, and the sampling bin 1 is provided with an operation window, so that a tester can conveniently operate the internal device of the sampling bin.
The two sampling bags 2 are arranged in the sampling bin 1, one sampling bag is used for containing a sample 3, and the other sampling bag is empty;
the sampling bag 2 adopts a Tedlar bag.
Sampling pump 8 has four, and per two sampling pumps correspond a sampling bag 2, sampling pump 8 respectively through teflon pipe 7 with the 2 tube coupling of sampling bag that correspond, wherein, every sampling bag 2's sack is connected with the one end of two teflon pipes 7 respectively, and the mounting hole on the 1 bulkhead in sampling storehouse is passed to the other end of two teflon pipes 7 to be connected with two sampling pumps 8 respectively.
The Teflon tube 7 penetrates through the sampling bin 1, and the length of the Teflon tube extending out of the sampling bin 1 is not more than 2 centimeters.
The number of the valves 4 is four, and the four valves are respectively and correspondingly installed at one end of the Teflon tube 7 connected with the sampling bag 2 so as to control the flow of the corresponding sampling bag 2 and the external air.
The two TENAX collecting pipes and the two DNPH collecting pipes are respectively and correspondingly detachably arranged at one end of a Teflon pipe 7 connected with a sampling pump 8, wherein one TENAX collecting pipe and one DNPH collecting pipe are correspondingly arranged on the Teflon pipe 7 correspondingly connected with each sampling bag 2;
the sampling pump 8 is connected with the flowmeter 9 through a pipeline, and the flowmeter 9 is used for measuring the sampling flow of the sampling pump 8 which is correspondingly connected;
the sampling pump 8 is respectively connected with a high-purity nitrogen source pipeline, so that high-purity nitrogen is pumped into the sampling bag 2 through the sampling pump 8 through the Teflon pipe 7;
sampling pump 8 respectively with exhaust gas recovery device tube coupling to the realization is taken the gas in sampling bag 2 out through sampling pump 8, collects through exhaust gas recovery device, in order to avoid polluting the environment.
The above-described embodiments of the present invention should not be construed as limiting the scope of the present invention. Any other corresponding changes and modifications made according to the technical idea of the present invention should be included in the protection scope of the claims of the present invention.