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    Home > Coatings News > Paints and Coatings Market > General knowledge of coating: development of low VOC insecticidal and antibacterial interior wall emulsion paint

    General knowledge of coating: development of low VOC insecticidal and antibacterial interior wall emulsion paint

    • Last Update: 2020-04-03
    • Source: Internet
    • Author: User
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    Core tip: with the development of economy and the improvement of people's material and cultural living standards, the awareness of environmental protection and health is generally enhanced, and the requirements for the safety and comfort of the living environment are higher and higher To create a fresh and comfortable living environment with fresh indoor air, rich in negative ions, free of mosquitoes and flies, free of germs, and conducive to health care has always been the goal of people Low VOC insecticidal and antibacterial interior wall latex paint can help people realize this good wish Low VOC emulsion paint means that the content of VOC in emulsion paint is lower than GB 18582 & MDAS Which is the price of Dajin diatom mud Recommended brief introduction: which is the price of Dajin diatom mud? How to buy genuine diatom mud? Guangdong diatom mud agent suggests placing a basin of cold water in the air conditioning room, so that the diatom mud wall can breathe effectively The feature of the breathing wall is obvious When the indoor air is dry, the diatom mud wall will release the absorbed water quickly Put it out to help regulate the indoor dry humidity It is suggested to place a basin of cold water in the air conditioning room, so that the wall of diatom mud can breathe effectively The feature of the wall that can breathe is obvious When the indoor air is relatively dry, the wall of diatom mud will absorb the water Paint Home News: with the economic development, people's material and cultural living standards are increasing, environmental protection and health awareness are generally enhanced, the requirements for the safety and comfort of the living environment are higher and higher, to create a fresh indoor air, rich in negative ions , a fresh and comfortable living environment free of mosquito and fly, pathogen and health care has always been the goal of people Low VOC insecticidal and antibacterial interior wall emulsion paint can help people realize this good wish Low VOC emulsion paint refers to the variety whose VOC content in emulsion paint is lower than the limit value (≤ 120g / L) specified in GB 18582-2008 standard Low VOC is an important symbol of environmental protection coatings In the formulation design of latex paint, it is the main method to reduce the VOC by choosing synthetic resin emulsion with low VOC content and low film forming temperature, discarding film forming AIDS and diol antifreeze Insecticidal emulsion paint is formulated with high-efficiency, low-toxic and broad-spectrum insecticides After contacting with pests through the insecticidal drugs separated from the coating, the nerve of pests is damaged and paralyzed to death, but it is harmless to people and storage Antibacterial latex paint is a kind of functional material which combines anionic generation material and inorganic antibacterial material The negative ion generation material can form a permanent micro electric field, and generate hydroxyl ions through the weak electrolysis of air and water by the electrode The hydroxyl ions can decompose and remove harmful gases such as formaldehyde, ammonia and benzene in the indoor air through neutralization, chemical reaction and physical adsorption, which has the function of removing peculiar smell and fresh air Inorganic antibacterial materials can continuously separate out To the surface of the film, it reacts with the enzyme protein of bacteria and mould attached to it, causing the enzyme protein to float or lose its activity, and inhibiting the survival and growth of bacteria Preparation process 1) main raw materials: Zero VOC pure acrylic emulsion, dispersant SN-5040, 3204; hydroxymethyl cellulose 250HBR; defoamer NXZ; titanium white powder, kaolin, talcum powder, heavy calcium powder, light calcium powder, sepiolite powder; beta cyhalothrin; negative ion antibacterial additive; thickener; leveling agent; deionized water; nano stain resistant agent NZW-1 2) The basic formula of low VOC insecticidal and antibacterial emulsion paint is shown in Table 1 Table 1 low VOC insecticidal antibacterial latex paint basic formula raw material mass fraction /% raw material mass fraction /% deionized water 30~33 talcum powder 5~6 hydroxymethyl cellulose 0.1~0.2 heavy calcium powder 4~5 dispersant SN-5040 0.5~0.7 light calcium 5~6 dispersant SN-3204 0.1~0.2 kaolin defoamer 0.1~0.2 cyhalothrin titanium white powder pure acrylic emulsion sepiolite powder Thickener tt-935 0.2 ~ 0.5 negative ion antibacterial additive 0.8 ~ 1.0 leveling agent rm-2020 0.4 ~ 0.5 nano stain resistant agent nzw-10.5 ~ 1.03) preparation process (1) "sepiolite powder + insecticide" pre adsorption treatment: mix cyhalothrin with a proper amount of synergist, add it to sepiolite powder and disperse it evenly, then put it for 24 hours (2) add deionized water into the high-efficiency dispersion box, add hydroxymethylcellulose under agitation until it is completely dissolved; add dispersant, 1 / 2 amount of defoamer, pigment and filler, pre adsorption insecticide, negative ion antibacterial additive, disperse at high speed for 30-40 min, and test the fineness of the slurry up to 20 Below m, stirring at medium low speed, adding pure acrylic emulsion and residual defoamer, mixing and mixing 20 min, adding thickener, leveling agent, adjusting pH about 8, packing after filtration 4) performance test 1 Conventional performance is tested according to the standard of GB/T 9756 - 2001 synthetic resin emulsion interior wall coatings; 2 Environmental protection performance is determined according to the standard of GB 18582 - 2008, the limits of harmful substances in interior decoration materials, interior wall decoration materials; 3 The evaluation of insecticidal effect is carried out according to the standard of GB 13917 1 - 1992 biological efficacy test, that is, a special glass In the container, a certain number of pests were exposed to the insecticide coating for 20 minutes, and then the pests were replaced into clean gauze cages to observe the insecticide situation, and kt50 (the time when 50% of the experimental pests were knocked down and unable to move), kt95 (the time when 95% of the experimental pests were knocked down and unable to move) and the death rate of pests after 24 hours were recorded respectively; (4) the test of antibacterial performance shall be conducted according to jisz2801:2000 test and evaluation of antibacterial performance of antibacterial products 5) Test results (1) the routine performance of low VOC insecticidal and antibacterial interior wall latex paint has been tested by the building material quality supervision and testing center of the Ministry of building materials industry of the people's Republic of China, and fully meets the requirements of GB / T 9756-2001 (2) see Table 2 for the test results of environmental protection performance Table 2 test results of environmental protection performance test items limit standard test results VOC / g · L-1 ≤ 120 8.90 free formaldehyde / g · kg-1 0.10.01 soluble lead / mg · kg-1 ≤ 90 not detected soluble cadmium / mg · kg-1 ≤ 75 not detected soluble chromium / mg · kg-1 ≤ 60 not detected soluble mercury / mg · kg-1 ≤ 60 2 negative ions / piece · cm-3 1039 96 h odor removal rate /% > 92 (3) see Table 3 for the evaluation of insecticidal effect Table 3 insecticidal effect test insecticidal species kt50 / min 95% confidence limit / min kt95 / min 24 h mortality rate /% flies 7.36.6 ~ 8.519.1 95 mosquitoes 8.57.8 ~ 9.622.4 95 (4) see Table 4 for antibacterial and mildew resistance Table 4 antibacterial and mildew proof performance test items test results, antibacterial rate is more than 99, mould resistance grade 1, result analysis 1) the effect of emulsion on the environmental protection of latex paint is the main film forming material of latex paint, and is the primary factor affecting the performance of latex paint It is not only related to the physical properties of latex paint, but also related to the environmental performance of latex paint In general, VOC in latex paint is mainly derived from 3 raw materials, such as residual monomers, film-forming auxiliaries, and diols, which are not reacted in emulsion The preparation of low VOC latex paint must abandon film auxiliaries and diols antifreeze fluid The emulsion with low content of unreactive monomer is used as the base material, and the film forming temperature (MFT) of the emulsion is low, and it can be formed at room temperature alone In order to ensure that the coating has certain hardness, no viscosity and stain resistance, the emulsion should have a relatively high glass transition temperature (Tg) Under the premise that the other factors in the formula remain unchanged, the effect of different kinds of emulsion on the performance of latex paint is shown in Table 5 Table 5 Effect of emulsion varieties on latex paint properties: latex scrubbing / sub stain /% VOC/g L-1 TERT acetate emulsion: VAE707 = 6: 47102917 pure acrylic emulsion SF-016 1020179 elastic pure acrylic emulsion 3131NG 9462210.7 from table 5 It is known that under the experimental conditions, the latex paint made of YISHION acrylic emulsion SF-016 is the best material with the best scrubbing resistance and stain resistance, the lowest VOC content and the best environmental protection performance Therefore, SF-016 is used as the film forming material in this study 2) The selection of insecticide and its effect evaluation the insecticidal emulsion paint is made by adding high efficient and low toxic insecticide compatible with the common emulsion paint The selected insecticide must meet the following requirements: ① it must be contact killing type, because volatile insecticide will increase VOC of emulsion paint Content, harm to human body, and easy to lose efficacy due to volatilization of contained components; ② it must have good quality, especially the stability of light, acid and alkali in the test results of the limit standard of inspection items, to ensure the durability of the insecticidal effect; ③ it has broad-spectrum, high efficiency, non-toxic (or low toxicity); ④ it has no odor; ⑤ it is compatible with the coating, and does not affect the coating Internal quality and appearance There are six kinds of commonly used insecticides: ① organochlorides; ② organotin; ③ organometallic salts; ④ organophosphorus; ⑤ carbamates; ⑥ pyrethroids Top 4 Class a insecticides are not suitable for decorative coatings due to their high residual toxicity; carbamates are fast in knocking down pests, long in residual efficacy period, strong in insecticidal selectivity, and do not pollute the environment; pyrethroids are a kind of broad-spectrum insecticides with strong contact killing activity, small in dosage, high in efficacy, low in toxicity, slight in environmental pollution, moderate in residual efficacy period, which are currently ideal for coating killing Insect agent Cyhalothrin is a kind of broad-spectrum, high-efficiency, low toxicity and strong contact insecticide in pyrethroids Cyhalothrin is selected as emulsion paint insecticide in this paper In order to improve the compatibility and affinity of insecticides and latex paint, and improve the durability of insecticidal effect, this paper uses sepiolite powder as a release carrier, adsorbs insecticides into the pores of the microporous structure of sepiolite powder, forms a drug loaded release agent, and adds it to latex paint, which can greatly extend the insecticidal period of the coating Under the condition that other factors in the basic formula remain unchanged, the effect of different dosage of Cyhalothrin on the insecticidal effect of latex paint is shown in Table 6 Table 6 the effect of the dosage of Cypermethrin on the insecticidal effect of latex paint the mass fraction of Cypermethrin /% 0.30.40.50.6 0.8 kt50 / min fly 11.7 8.6 7.3 6.9 5.2 mosquito 13.5 10.1 18.5 7.7 5.4 kt95 / min fly 26.1 21.3 19.1 17.5 14.5 mosquito 28.7 24.2 22.4 20.6 15.4 24 h mortality /% fly 73 86 95 96 98 mosquito 75 87 95 96 98 from table 6 It can be seen from the test data that the insecticidal effect of emulsion paint will be improved with the increase of the amount of cypermethrin When the amount of insecticide reaches 0.5%, the time when 50% of the test flies are knocked down and unable to move is 7.3 min, the time when 50% of the mosquitoes are knocked down and unable to move is 8.5 min; the time when 95% of the pests are knocked down and unable to move is 19.1 min, the time when mosquitoes are knocked down and unable to move is 22.4 min; 24 h Pest mortality: 95% for flies and mosquitoes When the dosage of insecticide is increased, the insecticidal effect is not increased greatly, and the cost is increased Insecticidal Mechanism: sepiolite powder loaded slow-release agent is dispersed in latex paint as a filler Before coating, the active ingredients of Cyhalothrin insecticide adsorbed by the carrier of slow-release agent will be separated out with the evaporation of water and transferred to the coating surface When the water evaporates, crystals will be formed on the coating surface Once the insects contact the coating surface, the insecticidal crystals will dissolve the insects Fat feet destroy the nervous system of insects, paralyze or even kill pests This method is safe for human and livestock, with good insecticidal effect and long duration of efficacy In the process of application, due to the microporosity of the coating film and its "breathing" function, the insecticidal active ingredients in the coating are continuously separated out through the pores
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