Method for detecting orthophthalic plasticizer in silicone sealant

Abstract

The invention discloses a method for detecting an orthophthalic plasticizer in a silicone sealant, which comprises the following steps: crushing a cured silicone sealant sample, and soaking in a solvent for 6-8 days to obtain a soaking solution; covering a potassium bromide wafer with the soaking solution, and after the solvent is naturally volatilized, carrying out infrared characterization on the soaking solution by adopting a Fourier transform infrared spectrometer to obtain an infrared spectrum; analyzing the obtained infrared spectrum, and judging whether the silicone sealant contains the orthophthalic plasticizer or not; and if the absorption peaks appear at 740-750cm <-1 > and 1720-1740cm <-1 >, judging that the silicone sealant contains the phthalate plasticizer. According to the phthalate plasticizer in the silicone sealant for the building, the alkane plasticizer and the phthalate plasticizer can be qualitatively detected on the basis of infrared spectroscopy, infrared testing is convenient and rapid, the detection cost is low, the accuracy is high, the testing time is short, and the capacity of batch analysis is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of sealing material detection, and particularly relates to a method for detecting o-phthalate plasticizers in silicone sealants for construction based on infrared detection. Background Art

[0002] As a high-performance elastic sealing material, silicone sealant for construction is widely used in scenes such as building curtain walls, door and window joints, and concrete expansion joints due to its excellent weather resistance, high and low temperature resistance, aging resistance and bonding properties. Moreover, with the improvement of urbanization level and the continuous improvement of people's requirements for housing and decoration, silicone sealant is also increasingly used in home decoration fields such as kitchen and bathroom countertops, washbasin edges, and toilet bases.

[0003] In recent years, with the growing development of the sealant industry and rising raw material prices, some companies have sacrificed product quality in pursuit of profits, replacing dimethyl silicone oil with inferior phthalate plasticizers. These plasticizers, as a type of environmental hormone, easily accumulate in the environment, polluting soil and water. They are enriched through the food chain, affecting the reproductive and developmental functions of humans and other organisms and interfering with the normal secretion of hormones in the body. Some phthalates (such as DEHP) are listed as potential carcinogens by the International Agency for Research on Cancer. Long-term exposure can lead to chronic poisoning through skin absorption or inhalation through the respiratory tract. In addition, due to the high toxicity and high risk of environmental residues of phthalates, the EU RoHS and REACH regulations have explicitly restricted and banned the use of many phthalate plasticizers (such as DEHP and DBP).

[0004] Products containing phthalate plasticizers may meet the requirements of relevant standards when they leave the factory, but they will deteriorate after a period of use. In mild cases, molecular migration will occur, leading to glass "tears" such as stickiness and stringing. In severe cases, sealant cracking and insulating glass unit oil leakage and failure may occur. The significant decline in mechanical properties, cracking and powdering of the colloid may cause curtain walls or doors and windows to fall off, endangering the life of the building and people's lives.

[0005] The current testing standard for alkane plasticizers in silicone sealants for construction is GB / T 31851-2015, "Test Methods for Alkane Plasticizers in Silicone Structural Sealant." This testing method primarily includes thermogravimetric analysis (TGA), thermogravimetric analysis, and infrared spectroscopy (FTIR). TGA and thermogravimetric analysis are used for quantitative detection, while FTIR is used for qualitative detection. These three methods are effective for detecting carbon-chain alkanes such as white oil and liquid paraffin. However, effective testing for non-carbon-chain alkanes such as cracked silicone oil and other alkanes has not yet been confirmed. Furthermore, research on the addition of phthalate plasticizers and testing methods is even more lacking. Currently, research and testing methods for the addition of phthalate plasticizers primarily focus on children's products, environmental products, medical foods, and even banned substances in automobiles. Testing methods primarily involve gas chromatography, gas chromatography-mass spectrometry, and liquid chromatography. Research on phthalate plasticizers in the construction sealant industry is scarce. Therefore, based on the product characteristics of sealants, a test method for phthalate plasticizers in construction silicone sealants was developed using Fourier transform infrared spectroscopy. This method improves the types and methods of plasticizer testing, strengthens the control of phthalate plasticizers in products, and protects the health and safety of construction workers and residents. This method also complies with environmental protection requirements and promotes policies to promote green industrial upgrading. Therefore, it is extremely necessary to accurately and effectively determine the content of phthalate plasticizers in construction sealants.

[0006] The disclosure of the above background technology content is only used to assist in understanding the inventive concept and technical solution of the present invention. It does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above content has been disclosed before the filing date of this patent application, the above background technology should not be used to evaluate the novelty and creativity of this application. Summary of the Invention

[0007] In view of this, in order to overcome the defects of the prior art, the object of the present invention is to provide an infrared spectroscopy detection method that can effectively detect phthalate plasticizers in silicone sealants for construction.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] A method for detecting phthalate plasticizers in silicone sealants for construction comprises the following steps:

[0010] The cured silicone sealant sample was crushed and immersed in a solvent for 6-8 days to obtain an immersion solution;

[0011] The soaking solution is covered on a potassium bromide wafer, and after the solvent evaporates naturally, the soaking solution is characterized by infrared using a Fourier transform infrared spectrometer to obtain an infrared spectrum;

[0012] Analyze the obtained infrared spectrum to determine whether the silicone sealant contains phthalate plasticizers;

[0013] If between 740 and 750 cm -1 and 1720~1740cm -1 If an absorption peak appears, it is determined that the silicone sealant contains phthalate plasticizers.

[0014] According to some preferred embodiments of the present invention, the cured silicone sealant sample is prepared by preparing a container with a cavity, filling the cavity with the silicone sealant, and curing the container in a constant temperature and humidity environment. Thereafter, the container is demolded and the sealant sample is taken out to obtain a cured silicone sealant sample.

[0015] According to some preferred embodiments of the present invention, the constant temperature and humidity are (23±2)°C and (50±5)%.

[0016] According to some preferred embodiments of the present invention, the silicone sealant is a single-component type, and the curing time is 6-8 days; the silicone sealant is a two-component type, and the curing time is 2-3 days.

[0017] According to some preferred embodiments of the present invention, the cured silicone sealant sample is a cured adhesive strip selected from a specific construction scenario.

[0018] According to some preferred embodiments of the present invention, the particle size of the crushed sample is 1 to 5 mm, so as to increase the contact area between the sample and the solvent and better extract the phthalate plasticizer contained in the sample.

[0019] According to some preferred embodiments of the present invention, the added volume of the solvent is twice the mass of the silicone sealant sample. For example, if the mass of the added silicone sealant sample is 10 g, the added volume of the solvent is 20 mL.

[0020] According to some preferred embodiments of the present invention, the solvent is acetone.

[0021] According to some preferred embodiments of the present invention, during the infrared characterization, the test light path of the Fourier transform infrared spectrometer uses the transmission method, and the wave number range is 400cm -1 ~4000cm -1 , spectral resolution is not less than 4cm -1 , the scanning number of 15-64 times is more appropriate, and the preferred range is 15 times.

[0022] According to some preferred embodiments of the present invention, the detection method further comprises determining whether an alkane plasticizer is present: if the infrared spectrum obtained has a value at 715 cm -1 ~725cm -1、1375cm -1 ~1385cm -1 、1450cm -1 ~1470cm -1 、2850cm -1 ~2860cm -1 、2920cm -1 ~2930cm -1 and 2955cm -1 ~2965cm -1 If any 4 or more corresponding absorption peaks appear, it can be determined that the silicone sealant contains alkane plasticizers.

[0023] Due to the adoption of the above technical solution, compared with the existing technology, the benefits of the present invention are: the phthalate plasticizers in the silicone sealant for construction of the present invention can be qualitatively detected as both alkane plasticizers and phthalate plasticizers based on infrared spectroscopy. Infrared testing is convenient and fast, with low testing cost, high accuracy, short testing time, and the ability to conduct batch analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 This is the infrared spectrum of the sealant without any plasticizer added, in which only the characteristic peak appears at 2962.92cm -1 , the wave number range is 2955cm -1 ~2965cm -1 The CH3 asymmetric stretching vibration peak appears.

[0026] Figure 2 This is the infrared spectrum of the sealant containing alkane plasticizer, where the characteristic peaks appear at 1457.32 cm -1 、2854.96cm -1 、2925.24cm -1 and 2961.87cm -1 , the wavenumber range is 1450cm -1 ~1470cm -1 The deformation vibration of CH2 or the asymmetric deformation vibration peak of CH3 appears, 2850cm -1 ~2860cm -1The symmetrical stretching vibration peak of CH2 CH bond appears at 2920cm -1 ~2930cm -1 The asymmetric stretching vibration peak of CH2 CH bond and 2955cm -1 ~2965cm -1 The asymmetric stretching vibration peak of CH3 appears.

[0027] Figure 3 This is the infrared spectrum of the sealant containing phthalate plasticizers. The characteristic peak positions are: one of the typical strongest peaks, the ester hydroxyl C=O peak at 1728.19 cm -1 The peak value of the out-of-plane bending vibration of the CH of the o-phenyl substituted benzene ring is 744.53 cm -1 , and the peak position is 1285.96cm -1 and 1122.58cm -1 The peak positions of phthalate plasticizers and alkane plasticizers will partially overlap, mainly in the wave number range of 1375cm -1 ~1385cm -1 The CH bond symmetric deformation vibration peak of CH3 appears at 2955cm -1 ~2965cm -1 The asymmetric stretching vibration peak of CH3 appears. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0029] The examples involve the addition amounts of various substances, where "parts" are by weight unless otherwise specified. Unless otherwise specified, all raw materials in the following examples are commercially available or prepared by conventional methods in the art.

[0030] Some of the raw materials, instruments and manufacturer's brands in the examples are as follows:

[0031] Acetone: analytical grade, content ≥99.5%, Jiangsu Qiangsheng Functional Chemical Co., Ltd.

[0032] Fourier transform infrared spectrometer: equipment model NicoletiS10, wave number range 400-4000cm -1 , spectral resolution is not less than 4cm -1, scan times 15 times.

[0033] The present invention's infrared-based method for detecting plasticizers in sealants utilizes infrared spectroscopy for identification. It can not only qualitatively test for alkane plasticizers but also detect the presence of phthalate plasticizers. It can also assist in quantifying the plasticizer content based on the area of ​​the absorption peak. This method is not only convenient and fast, with low testing costs, but also highly accurate, with a short testing time, and capable of batch analysis.

[0034] The method for detecting phthalate plasticizers in silicone sealants for construction of the present invention comprises the following steps:

[0035] Step S1: Sample preparation

[0036] The cured silicone sealant sample was crushed and immersed in a solvent for 6-8 days to obtain an immersion solution.

[0037] 1) If testing uncured silicone sealant, first prepare a container with a cavity, fill the cavity with silicone sealant, and cure it in a constant temperature and humidity environment. Then, remove the container from the mold and remove the sealant sample to obtain a cured silicone sealant sample.

[0038] The constant temperature and humidity are 23±2°C and 50±5%. The container with a cavity can be made of metal, glass or anti-stick material to form a cavity of 200mm×10mm=5mm, and the silicone sealant sample is filled into the cavity using a glue gun.

[0039] If the silicone sealant is a single-component type, the curing time is 6-8 days; if the silicone sealant is a two-component type, the curing time is 2-3 days.

[0040] 2) If the silicone sealant that has been cured in a specific construction scenario is to be tested, the silicone sealant strip after curing is directly selected as the cured silicone sealant sample.

[0041] If you disassemble the insulating glass prefabricated parts, take out the cured second sealant strip and take 10g of the center part of the strip; if you are testing the phthalate plasticizer in the silicone sealant for a completed curtain wall structure project, select 10g of the strip according to the actual project conditions.

[0042] The sample particle size after crushing is 1-5 mm to increase the contact area between the sample and the solvent, thereby better extracting the phthalate plasticizers contained in the sample. The solvent is acetone. The added volume of solvent is twice the mass of the silicone sealant sample. For example, if the mass of the silicone sealant sample is 10 g, the added volume of solvent is 20 mL.

[0043] Step S2: Infrared spectrum test

[0044] Turn on the instrument for preheating, subtract the air background and solvent scanning, cover the immersion liquid on the potassium bromide wafer, wait for the solvent to evaporate naturally, and use Fourier transform infrared spectrometer to perform infrared characterization on the immersion liquid to obtain the infrared spectrum.

[0045] During infrared characterization, the Fourier transform infrared spectrometer uses the transmission method instead of the reflection method for the test light path, adopts higher sensitivity and wider wave number range, and the wave number range is 400cm -1 ~4000cm -1 , spectral resolution is not less than 4cm -1 , the number of scans is adjusted to 15 times.

[0046] Step S3: Spectral analysis

[0047] The obtained infrared spectrum is analyzed to determine whether the silicone sealant contains phthalate plasticizers.

[0048] If between 740 and 750 cm -1 and 1720~1740cm -1 If an absorption peak appears, it is determined that the silicone sealant contains phthalate plasticizers.

[0049] The infrared spectral characteristics of phthalate plasticizers are mainly related to the ester group (-COOR), ortho-substituted benzene ring and related functional groups in their molecules. The following are the characteristics and analysis of the typical absorption peaks of phthalate plasticizers in their infrared spectra:

[0050] 1. Characteristic absorption of ester group (-COOR)

[0051] C=O stretching vibration (ester carbonyl): position about 1720 cm -1 ~1740cm -1 (Strong peak), which is a significant feature of the ester group, with high absorption intensity and sharp peak shape, and is usually one of the strongest peaks. If there is conjugation or hydrogen bonding effect (such as partial hydrolysis) in the phthalate ester, the C=O peak may shift to the low frequency direction (about 1700cm -1 ~1720cm -1 ).

[0052] COC asymmetric stretching vibration (ester bond): position about 1250 cm -1 ~1300cm -1 (strong peak) and 1100cm -1 ~1150cm -1 (Medium-strong peak), the two CO vibrations of the ester bond sometimes appear as double peaks, the former corresponding to the asymmetric stretching vibration frequency at 1285 cm -1 The latter is a symmetrical stretching vibration with a frequency of 1125 cm -1 nearby.

[0053] 2. Characteristic absorption of ortho-substituted benzene ring

[0054] Benzene ring C=C skeleton vibration: position about 1600cm -1 、1580cm -1 、1480cm -1 (Medium intensity peak), the conjugation effect of the ortho-substituted benzene ring leads to multiple C=C stretching vibration peaks.

[0055] Out-of-plane bending vibration of the CH ring of the ortho-substituted benzene ring: position about 740 cm -1 ~750cm -1 (strong peak), characteristic absorption peak of ortho-substituted benzene ring (para-substituted usually appears at about 800 cm -1 ).

[0056] 3. Other related absorption peaks

[0057] CH vibration of aliphatic chain (RO-): position 2850cm -1 ~2950cm -1 (CH stretching vibration, such as -CH2 or -CH3 in ester groups); 1370 cm -1 ~1380cm -1 (Symmetrical bending vibration of CH3 if methyl group is present).

[0058] Benzene ring CH stretching vibration: position about 3050cm -1 ~3100cm -1 (Weak to moderate intensity, aromatic CH stretching vibration).

[0059] like Figure 1-3 As shown, the infrared spectrum of alkane plasticizers appears in the wave number range of 715cm -1 ~725cm -1 、1375cm -1 ~1385cm -1 、1450cm -1 ~1470cm -1 、2850cm -1 ~2860cm -1 、2920cm -1 ~2930cm -1 and 2955cm -1 ~2965cm -1 , phthalate plasticizers at 2920cm -1 ~2930cm -1 、2955cm -1 ~2965cm -1There may be some peak overlap at other positions, but at 740cm -1 ~750cm -1 Strong peak, 1250cm -1 ~1300cm -1 Strong peak, 1720cm -1 ~1740cm -1 Strong peak, 1100cm -1 ~1150cm -1 The medium-strong peaks of the -1 about) and benzene ring (740cm -1 When the sample contains characteristic functional groups such as phthalate ester plasticizers, it can be determined that the sample contains phthalate ester plasticizers. -1 and 1720~1740cm -1 If an absorption peak appears, it can be determined that the silicone sealant contains phthalate plasticizers; in the infrared spectrum detected, the absorption peak at 715cm -1 ~725cm -1 、1375cm -1 ~1385cm -1 、1450cm -1 ~1470cm -1 、2850cm -1 ~2860cm -1 、2920cm -1 ~2930cm -1 and 2955cm -1 ~2965cm -1 If any four or more corresponding absorption peaks appear, it can be determined that the silicone sealant contains alkane plasticizers; if the infrared spectrum detected also contains 740-750cm -1 and 1720~1740cm -1 The absorption peak at 715 cm -1 ~725cm -1 、1375cm -1 ~1385cm -1 、1450cm -1 ~1470cm -1 、2850cm -1 ~2860cm -1 、2920cm -1 ~2930cm -1 and 2955cm -1 ~2965cm -1 If any four or more corresponding absorption peaks appear, it can be determined that the silicone sealant contains both alkane plasticizers and phthalate plasticizers.

[0060] Example 1 Qualitative Detection of Phthalate-like Plasticizers in Two-Component Silicone Sealant

[0061] The method for detecting phthalate plasticizers in silicone sealant for construction of this embodiment comprises the following steps:

[0062] 1. Sample Preparation

[0063] Take a two-component silicone sealant (component A: base glue; component B: curing agent), mix them in proportion, and inject them into the cavity of a 200mm×10mm×5mm container. Cure them at a temperature of 23±2℃ and a relative humidity of 50±5% for 2 days. After demolding, take out the glue sample.

[0064] Take 10 g of the cured rubber sample from the center, cut it into pieces, and place it in a 50 mL conical flask and soak it in 20 mL of acetone for 7 days. During this period, shake it every day to accelerate the dissolution of the plasticizer to obtain the soaking solution.

[0065] 2. Infrared spectrum test

[0066] The infrared spectrum test uses a Fourier transform infrared spectrometer with the following parameters: wave number range 400cm -1 ~4000cm -1 , resolution 4cm -1 15 scans were performed using the transmission method. After warming up the instrument for 30 minutes, the air and acetone backgrounds were subtracted. One drop of the immersion solution was evenly applied to a potassium bromide wafer. After the acetone evaporated completely, an infrared spectrum scan was performed.

[0067] 3. Spectral Analysis

[0068] Infrared spectrum such as Figure 1 As shown. Among them, 2963cm -1 : fatty chain CH stretching vibration peak;

[0069] Judgment: Compare the above characteristic peaks with the typical characteristic peaks of alkane plasticizers (715cm -1 ~725cm -1 、1375cm -1 ~1385cm -1 、1450cm -1 ~1470cm -1 、2850cm -1 ~2860cm -1 、2920cm -1 ~2930cm -1 and 2955cm -1 ~2965cm -1The corresponding 4 or more absorption peaks appear), does not contain alkane plasticizers, and by comparing the typical characteristic peaks of phthalate plasticizers (740-750cm -1 and 1720~1740cm -1 ), does not contain phthalate plasticizers.

[0070] Example 2 Qualitative Detection of Phthalate-like Plasticizers in One-Component Silicone Sealant

[0071] The method for detecting phthalate plasticizers in silicone sealant for construction of this embodiment comprises the following steps:

[0072] 1. Sample Preparation

[0073] A sample of a certain brand of one-component silicone sealant was filled into the cavity of a 200mm × 10mm × 5mm container using a glue gun. The sample was then cured for 7 days at a temperature of (23±2)°C and a relative humidity of (50±5)%. After demolding, 10g of the cured sample was cut into pieces and placed in a 50mL conical flask. 20mL of acetone solution was added, and the flask was sealed and soaked for 7 days, with daily shaking to accelerate the dissolution of the plasticizer. This yielded a soaking solution.

[0074] 2. Infrared spectrum test

[0075] The instrument parameters are the same as those in Example 1. The soaking solution is applied to a potassium bromide wafer and the infrared spectrum is measured.

[0076] 3. Spectral Analysis

[0077] Infrared spectrum such as Figure 2 As shown. Among them, 2962cm -1 、2925cm -1 、2855cm -1 : fatty chain CH stretching vibration peak; 1457cm -1 : Deformation vibration of CH2 or asymmetric deformation vibration peak of CH3.

[0078] Judgment: The above characteristic peaks are consistent with the typical characteristic peaks of alkane plasticizers (715cm -1 ~725cm -1 、1375cm -1 ~1385cm -1 、1450cm -1 ~1470cm -1 、2850cm -1 ~2860cm -1 、2920cm -1 ~2930cm -1 and 2955cm -1 ~2965cm -1The corresponding absorption peaks appear in any 4 or more) and are consistent with the infrared spectrum of GB / T 31851 alkane plasticizers Figure 1 So, 1457.32cm appeared -1 、2854.96cm -1 、2925.24cm -1 and 2961.87cm -1 4 absorption peaks, containing alkane plasticizers, and by comparing the typical characteristic peaks of phthalate plasticizers (740-750cm -1 and 1720~1740cm -1 ), does not contain phthalate plasticizers.

[0079] Example 3 Detection of Phthalate Plasticizers in Sealant of Finished Insulating Glass Preforms

[0080] The method for detecting phthalate plasticizers in silicone sealant for construction of this embodiment comprises the following steps:

[0081] 1. Sample Preparation

[0082] Take 10g of the cured sample of a hollow glass silicone sealant sample, cut it into pieces and place it in a 50mL conical flask, add 20mL of acetone solution, seal it and soak it for 7 days. During this period, shake it 3 times a day to accelerate the dissolution of the plasticizer to obtain the soaking solution.

[0083] 2. Infrared spectrum test

[0084] The instrument parameters are the same as those in Example 1. The soaking solution is applied to a potassium bromide wafer and the infrared spectrum is measured.

[0085] 3. Spectral Analysis

[0086] Infrared spectrum such as Figure 3 As shown. Among them, 1728cm -1 : Strong absorption peak of ester carbonyl (C=O); 1286 cm -1 and 1123cm -1 : Asymmetric and symmetric stretching vibration peaks of ester bond COC; 745cm -1 : Strong peak of out-of-plane bending vibration of CH of ortho-substituted benzene ring; 1600cm -1 、1580cm -1 、1466cm -1 : Medium intensity peak of benzene ring C=C skeleton vibration.

[0087] Judgment: The above characteristic peaks are consistent with the typical characteristic peaks of phthalate plasticizers (740-750cm -1 and 1720~1740cm -1), confirming that the sample contains phthalate plasticizers.

[0088] In other embodiments, if the infrared spectrum detected is between 740 and 750 cm -1 and 1720~1740cm -1 If an absorption peak appears, it can be determined that the silicone sealant contains phthalate plasticizers; in the infrared spectrum detected, the absorption peak at 715cm -1 ~725cm -1 、1375cm -1 ~1385cm -1 、1450cm -1 ~1470cm -1 、2850cm -1 ~2860cm -1 、2920cm -1 ~2930cm -1 and 2955cm -1 ~2965cm -1 If any four or more corresponding absorption peaks appear, it can be determined that the silicone sealant contains alkane plasticizers; if the infrared spectrum detected also contains 740-750cm -1 and 1720~1740cm -1 The absorption peak at 715 cm -1 ~725cm -1 、1375cm -1 ~1385cm -1 、1450cm -1 ~1470cm -1 、2850cm -1 ~2860cm -1 、2920cm -1 ~2930cm -1 and 2955cm -1 ~2965cm -1 If any four or more corresponding absorption peaks appear, it can be determined that the silicone sealant contains both alkane plasticizers and phthalate plasticizers. Both plasticizers are mixtures of several substances, not a single substance.

[0089] Given the complexity and diversity of existing alkane plasticizers, this invention addresses the gaps and deficiencies in the existing technology. Building on research related to alkane plasticizers, this invention provides a rapid infrared spectroscopic method for the determination of phthalate plasticizers in silicone sealants for construction by analyzing the characteristic peaks of phthalate plasticizers and comparing the positions and intensities of the characteristic peaks of numerous alkane and phthalate plasticizer sealants. This method is simple, accurate, low-cost, and quick to perform batch analysis, offering significant application and promotional value for the accurate analysis of phthalate plasticizers.

[0090] Specifically, the rapid detection method of plasticizers in silicone sealants for construction of the present invention is carried out by infrared spectroscopy, wherein the infrared spectroscopy comprises the following steps: 1) using a Fourier transform infrared spectrometer, selecting a transmission method for the test light path instead of a reflection method, using a higher sensitivity and a wider wave number range, the wave number range being 400 cm -1 ~4000cm -1 , spectral resolution is not less than 4cm -1 , set the scan count to 15. 2) Specimen Preparation: Assemble a 200mm × 10mm × 5mm cavity using anti-sticking material. Fill the cavity with the sample using a glue gun. Cure the single-component sealant at (23±2)°C and relative humidity (50±5)% for 7 days. Due to different curing mechanisms, cure the two-component sealant for 2 days. After demolding, remove the sealant sample and cut 10g of the sample into small pieces to increase the contact surface between the sample and the solvent. Place the sample in a 50mL Erlenmeyer flask and soak it in 20mL of acetone for 7 days. Liquid sample preparation is critical. Solvents are required to extract the plasticizer from the sealant sample. Given the plasticizer's solubility, acetone is used. Alternatively, disassemble the insulating glass preform, remove the cured second sealant strip, and sample 10g from the center. Alternatively, for testing phthalate plasticizers in completed curtain wall structures, remove 10g of the sealant strip based on the actual project conditions and soak it for 7 days using the above method before use. 3) Test: Turn on the instrument and preheat, subtract the air background and solvent scan, apply one drop of immersion liquid to the potassium bromide wafer, wait for the solvent to evaporate naturally, and then perform infrared characterization and infrared spectrum analysis on the immersion liquid. Due to the application of the above technical solution, the detection method of the present invention has the following advantages:

[0091] 1. The preparation and processing are simple, efficient and fast. Sample preparation does not require complicated operations. It only requires gluing and scraping in a fixed cavity. Soaking does not require complicated chemical reagents. The infrared spectroscopy detection process usually takes only tens of seconds or 1 minute. There is no need for long-term sample pretreatment, which significantly improves the analysis efficiency. The operation is simple and efficient, and it is especially suitable for batch sample testing.

[0092] 2. It has the potential to detect multiple components simultaneously. If the sample contains multiple plasticizers (such as alkanes and phthalates), it can achieve synchronous analysis through characteristic peaks, detect multiple plasticizers at the same time, and improve detection efficiency;

[0093] 3. The characteristic functional groups of phthalates have obvious absorption in the infrared spectrum, making them easy to identify. The structural differences between phthalates and alkane plasticizers do not affect the detection results, because phthalates contain aromatic rings and ester groups, which may have more characteristic peaks in the infrared spectrum, while alkanes are mainly CH bonds and may be more easily interfered with by other substances. Therefore, using infrared spectroscopy to detect phthalates is more advantageous because the characteristic peaks are more obvious and easier to distinguish;

[0094] 4. Infrared spectroscopy can not only qualitatively confirm the type of plasticizer through the position and intensity of characteristic peaks, but also realize auxiliary quantitative analysis through standard curves or peak area integration. It has comprehensive functions and realizes the combination of qualitative and quantitative analysis.

[0095] The above embodiments illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made based on the spirit of the present invention are intended to be covered by the scope of protection of the present invention.

[0096] The above-described embodiments, prepared by the methods of the present invention, are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the present invention and implement it accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent variations or modifications made in accordance with the spirit and substance of the present invention are intended to be encompassed within the scope of protection of the present invention.

[0097] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

Claims

1. A method for detecting phthalate plasticizers in silicone sealants, characterized in that: The steps include: The cured silicone sealant sample was crushed and immersed in a solvent for 6-8 days to obtain an immersion solution; The soaking solution is covered on a potassium bromide wafer, and after the solvent evaporates naturally, the soaking solution is characterized by infrared using a Fourier transform infrared spectrometer to obtain an infrared spectrum; Analyze the obtained infrared spectrum to determine whether the silicone sealant contains phthalate plasticizers; If between 740 and 750 cm -1 and 1720~1740cm -1 If an absorption peak appears, it is determined that the silicone sealant contains phthalate plasticizers.

2. The detection method according to claim 1, wherein The cured silicone sealant sample is prepared by preparing a container with a cavity, filling the cavity with the silicone sealant, curing it in a constant temperature and humidity environment, and then demolding the container and taking out the sealant sample to obtain the cured silicone sealant sample.

3. The detection method according to claim 2, characterized in that The constant temperature and humidity are 23±2° C. and 50±5% relative humidity.

4. The detection method according to claim 2, characterized in that The silicone sealant is a single-component type and has a curing time of 6-8 days; the silicone sealant is a two-component type and has a curing time of 2-3 days.

5. The detection method according to claim 1, wherein The cured silicone sealant sample is a cured silicone sealant strip selected from a specific construction scenario.

6. The detection method according to claim 1, characterized in that The particle size of the crushed sample is 1 to 5 mm.

7. The detection method according to claim 1, characterized in that The added volume of the solvent is twice the mass of the silicone sealant sample.

8. The detection method according to claim 1, wherein The solvent is acetone.

9. The detection method according to claim 1, wherein During the infrared characterization, the test light path of the Fourier transform infrared spectrometer uses the transmission method, and the wave number range is 400cm -1 ~4000cm -1 , spectral resolution is not less than 4cm -1 .

10. The detection method according to any one of claims 1 to 9, characterized in that: The detection method also includes judging whether an alkane plasticizer is present: if the infrared spectrum obtained has a value at 715 cm -1 ~725cm -1 、1375cm -1 ~1385cm -1 、1450cm -1 ~1470cm -1 、2850cm -1 ~2860cm -1 、2920cm -1 ~2930cm -1 and 2955cm -1 ~2965cm -1 If any 4 or more corresponding absorption peaks appear, it can be determined that the silicone sealant contains alkane plasticizers.

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