CN-121994973-A - Quick detection method for mildew-proof durability of building mildew-proof coating

CN121994973ACN 121994973 ACN121994973 ACN 121994973ACN-121994973-A

Abstract

The invention discloses a rapid detection method for mildew-proof durability of a building mildew-proof coating, and belongs to the technical field of coating detection. The method comprises the steps of preparing a coating test board, measuring initial content a 0 of a target mildew inhibitor in the coating test board, placing the test board in a high-temperature and high-humidity environment for accelerated aging, measuring residual content a 1 of the target mildew inhibitor in the aged coating, calculating retention rate R= (a 1 /a 0 ) x 100% of the mildew inhibitor, and rapidly obtaining mildew-proof persistence grade of the coating according to a comparison result of an R value and a preset evaluation standard. The invention replaces the traditional mould culture observation method which is as long as 28 days by quantifying the loss rate of the active ingredients of the mildew preventive before and after simulated aging, and greatly shortens the detection period from more than 35 days to 10-15 days. The method is suitable for building mildew-proof paint added with isothiazolinone mildew inhibitor, realizes quick, quantitative and objective mildew-proof durability evaluation, and is suitable for mass quick detection requirements in quality control and engineering inspection and reception.

Inventors

ZHANG GUANGYU
JIANG HUI
JIN QICHUN
ZHENG SHUQIAN
YANG QILI
AN JING
WANG XIAOGE
CHEN BINWEI
XUE JUNJIE
ZHOU YUWEI

Assignees

浙江方圆检测集团股份有限公司

Dates

Publication Date: 20260508
Application Date: 20260327

Claims (10)

1. A rapid detection method for mildew-proof durability of building mildew-proof paint is characterized by comprising the following process steps: s1, preparing a test board, namely uniformly coating the building mildew-proof coating to be tested on a standard test board, and curing to prepare a coated test board; S2, measuring the initial content of the mildew preventive, namely acquiring a part of the test board from the coated test board prepared in the step S1, and measuring the initial content a 0 of the target mildew preventive in the coating of the test board; S3, a damp-heat accelerated aging test, namely placing the residual coating test board prepared in the step S1 in a damp-heat simulation environment to perform the accelerated aging test; S4, measuring the content of the mildew inhibitor after aging, namely measuring the residual content a 1 of the target mildew inhibitor in the aged coating test board after the damp-heat accelerated aging test in the step S3 is finished; And S5, evaluating mildew-proof durability, namely calculating retention rate R of the mildew-proof agent, R= (a 1 /a 0 ) multiplied by 100% according to a 0 measured in the step S2 and a 1 measured in the step S4, and grading the mildew-proof durability of the building mildew-proof paint to be tested according to the corresponding relation between the pre-established retention rate R of the mildew-proof agent and the mildew-proof grade.
2. The method for rapidly detecting the mildew-proof durability of a building mildew-proof coating according to claim 1, wherein in the step S3, the test temperature of an accelerated aging test is set to be 40+/-1 ℃, the relative humidity is set to be 96+/-2%, and the time period of the accelerated aging test is set to be 7 days to 28 days.
3. The method for rapidly detecting the mildew-proof durability of the building mildew-proof coating according to claim 1, wherein a corresponding relation model between the retention rate R of the mildew-proof agent and the mildew-proof grade is as follows: When R is more than or equal to 75%, judging that the mildew-proof persistence grade is 0 grade; When the R is more than or equal to 60 percent and less than 75 percent, judging the mildew-proof durability grade to be 1 grade; When the R is more than or equal to 40% and less than 60%, judging that the mildew-proof durability grade is 2 grade; When R is more than or equal to 20% and less than 40%, judging that the mildew-proof durability grade is 3 grade; when R < 20%, the mildew-proof durability grade is judged to be grade 4.
4. The rapid detection method for the mildew-proof durability of the building mildew-proof coating according to claim 1 is characterized in that in the step S2 and the step S4, the content of a mildew-proof agent in the coating is measured by adopting a high performance liquid chromatography method, and the target mildew-proof agent is an isothiazolinone mildew-proof agent.
5. The rapid detection method for the mildew-proof durability of the building mildew-proof coating according to claim 1, wherein in the steps S2 and S4, the pretreatment method for measuring the mildew-proof agent content is that a coating is completely scraped from a test plate, crushed at room temperature and then passes through a 0.5mm metal sieve, a sample is accurately weighed, the volume is fixed by methanol, the sample is oscillated and dispersed and centrifuged, and a supernatant is filtered by an organic phase microporous filter membrane and then is to be detected.
6. The rapid detection method for the mildew-resistant durability of the building mildew-resistant coating according to claim 4, wherein the isothiazolinone mildew inhibitor comprises any one or more of 2-n-octyl-4-isothiazolin-3-One (OIT), 1, 2-benzisothiazolin-3-one (BIT) and 4, 5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT).
7. The rapid detection method for the mildew-proof durability of the building mildew-proof coating according to claim 6, wherein when the target mildew-proof agent is OIT, the detection condition of the high performance liquid chromatography is that a C18 reversed phase chromatographic column is adopted, a mobile phase is a 0.02mol/L ammonium acetate aqueous solution-methanol system, gradient elution is adopted, and the detection wavelength is 275nm.
8. The method for rapidly detecting the mildew-proof durability of a building mildew-proof coating according to claim 1, wherein in the step S1, two coating steps are performed by using a wire rod coater, and the second coating step is performed after curing for 6 hours after the first coating step. The standard test plate is an aluminum alloy plate with surface treatment conforming to GB/T9271, the curing environment is a standard test environment with the temperature of 23+/-2 ℃ and the relative humidity of 50+/-5%, and the total curing time is 168 hours.
9. The rapid detection method according to claim 1, wherein in the step S3, the coated test plate is vertically hung in a constant temperature and humidity environment, the distance between the test plates is not less than 20mm, the test plates are not contacted with the walls and the doors of the environment cavity, and in the step S4, the aged coated test plate is subjected to post-treatment before measurement, namely, the surface of the test plate is washed by flowing water, surface floating dust and precipitates are removed, and the test plate is placed under standard test conditions for 24 hours after moisture is absorbed.
10. The method for rapidly detecting the mildew-proof durability of a building mildew-proof coating according to claim 1, wherein in the step S5, when the relative deviation of the mildew-proof agent content measurement results of two test boards tested in parallel is more than 10%, the test is conducted again, and when the coating to be tested contains a plurality of target mildew-proof agents, the minimum value of the retention rate of each mildew-proof agent is taken as the retention rate R of the comprehensive mildew-proof agent to be rated.

Description

Quick detection method for mildew-proof durability of building mildew-proof coating Technical Field The invention belongs to the technical field of paint performance detection, and particularly relates to a rapid detection method for the mildew-proof durability of a building mildew-proof paint, which is suitable for performance detection of the building mildew-proof paint added with isothiazolinone mildew-proof agents. Background The building mildew-proof paint can inhibit the growth of mildew by adding a mildew-proof agent, and the mildew-proof durability is a key index for measuring the quality of the paint. At present, the main method for evaluating the mildew resistance of the paint in the industry is a mildew resistance test method widely applied in the industry by inoculating a test plate coated with the paint with a mixed mildew spore suspension, culturing for 28 days under the conditions of constant temperature and constant humidity and grading according to the mildew growth area of the surface of the test plate according to GB/T1741-2020 paint film mildew resistance assay. Although the method has visual and reliable results, the following defects are also present: (1) The detection period is too long, and the rapid evaluation requirement cannot be met, namely, the traditional method needs a mould culture period of at least 28 days, and the whole detection process exceeds 35 days in addition to the test plate preparation, pretreatment and result observation time. The long period can not meet the requirement of rapid iteration of the formula in the development of modern coatings, and is also delayed from the rapid acceptance requirement of engineering ends on the incoming materials, and delayed from the production and engineering application rhythms. (2) The quantitative rapid evaluation system is lacking, and the prior art is mainly used for carrying out qualitative rating through apparent mildew conditions and cannot provide quantitative mildew-proof durability indexes. Although the prior art can detect the initial content of the mildew preventive in the liquid paint by the standards of GB/T37363.1-2019, GB/T37363.4-2020 and the like, the methods only aim at the liquid paint, can not reflect the consumption condition of the mildew preventive in the use process of the paint, and can not directly relate the residual quantity of the mildew preventive with the mildew preventive durability. (3) The traditional mould culture test involves multiple links such as test plate preparation, spore suspension preparation, inoculation, culture, observation and rating, each link is influenced by manual operation and environmental factors, so that parallel sample deviation is large, control difficulty is high, and consistency of detection results among different laboratories is poor. (4) The method has low detection efficiency and is difficult to detect in batches, the mould culture test of the traditional method needs to occupy a large amount of constant temperature and constant humidity culture equipment, the number of single-batch detectable samples is limited, and high-flux detection cannot be realized, so that the cost is high and the efficiency is low when a third party detection mechanism detects in batches. The isothiazolinone mildew inhibitor is the most widely applied mildew inhibitor in the building mildew-resistant paint at present, and comprises OIT, BIT, DCOIT and other single varieties and various compound systems, the migration loss rule of the isothiazolinone mildew inhibitor in the coating is directly related to the mildew resistance, but the prior art does not have a quick and quantitative detection method for the mildew resistance persistence of the mildew-resistant paint. Therefore, there is a need to develop a detection method capable of rapidly, accurately and quantitatively evaluating the mildew-proof durability of a building mildew-proof coating, so as to solve the above problems in the prior art. Disclosure of Invention Aiming at the problems, the invention provides a rapid detection method for the mildew-proof durability of a building mildew-proof coating, which aims to solve the problems of long detection period, qualitative result, complex operation, low flux and incapability of quantitatively predicting the durability in the prior art. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: the invention provides a rapid detection method for mildew-proof durability of a building mildew-proof coating, which comprises the following process steps: s1, preparing a test board, namely uniformly coating the building mildew-proof coating to be tested on a standard test board, and curing to prepare a coated test board; S2, measuring the initial content of the mildew preventive, namely acquiring a part of the test board from the coating test board prepared in the step S1 as a control test board, and measuring the initial content a 0 of the target milde