The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform
Du Guan-ben - One of the best experts on this subject based on the ideXlab platform.
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Effects of resin-based Formaldehyde scavenger on performance of urea-Formaldehyde
China Forestry Science and Technology, 2020Co-Authors: Du Guan-benAbstract:A resin-based Formaldehyde scavenger was prepared in laboratory and mixed with urea-Formaldehyde(UF) resins with different F/U molar ratios.Its influence on mechanical performances and Formaldehyde emission of UF-bonded particleboard was investigated.The results showed that the Formaldehyde scavenger could effectively reduce the Formaldehyde emission from particleboard,but had a negative influence on board strengths.The F/U molar ratio was the main factor that influenced both above properties.When the F/U ratio was 1∶1 and the Formaldehyde scavenger content was 5% of the glue consumption,the Formaldehyde emission from particleboard was at E1 level and the internal bond met national standard for indoor panel.For the F/U ratio of 1.2∶1 and Formaldehyde scavenger content of 20%,the performance of particleboard could met with the requirements of national standard.
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Application of montmorillonite in Formaldehyde based resins
Adhesion in China, 2020Co-Authors: Du Guan-benAbstract:Application of montmorillonite(MMT) in Formaldehyde based resin was reviewed,inclding its characteristics and applications in phenol Formaldehyde resin,urea Formaldehyde resin,melamine Formaldehyde,styrene-acrylic acid coating and cement based coating particularly.
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Advancement on low toxic urea-Formaldehyde resin in China
Adhesion in China, 2020Co-Authors: Du Guan-benAbstract:The advancement on low toxic urea-Formaldehyde resin in China was reviewed.The methods for controlling free Formaldehyde emission were introduced particularly,including study of synthesis of urea-Formaldehyde resin,reducing the resolving of hydroxyl,interior methyl ether and half-condensed Formaldehyde,catching of free Formaldehyde released out during curing,and modification of urea-Formaldehyde resin.
Joaquim Font - One of the best experts on this subject based on the ideXlab platform.
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Dyestuffs and Formaldehyde content in split leather treated with Formaldehyde resins
Dyes and Pigments, 2018Co-Authors: Agustí Marsal, Sara Cuadros, Joaquim Font, Rosa M. Cuadros, Albert M. ManichAbstract:Abstract Formaldehyde resins are present in textile, leather and wood industries. Due to the harmful character of Formaldehyde, different alternatives have been found to exclude or reduce its content on processed goods. However, the effect of dyestuffs on the Formaldehyde content of goods containing Formaldehyde-synthesized resins has not been studied up to date. The aim of this work is to check if the presence of free amino groups in the structure of dyestuffs exerts an influence on the Formaldehyde content on leathers treated with Formaldehyde-synthesized resins. Six dyes, belonging to three different families (acid dyes, direct dyes and basic dyes), have been taken as examples to evaluate how their structures affect the reaction with Formaldehyde present in leather. The variation of the Formaldehyde content in dyed leathers with respect to control samples (treated with resin only) and its evolution with time have been also considered. It has been found that the ability of dyes in reducing the Formaldehyde content in leather depends on the amount of amino groups amenable to reaction with Formaldehyde. Those amino groups that in their vicinity have other functionalities, with which to form relatively stable structures, have a reduced reactivity with Formaldehyde. The reduction ability of dyes also depends on the Formaldehyde content in leather. The lower the Formaldehyde content is in the leather, the higher this reduction ability. Acid Black 234 dye caused a Formaldehyde content reduction of approximately 84% in leathers treated with melamine-Formaldehyde resin of low Formaldehyde content in the analysis carried out after 90 days of leather processing whereas the reduction was approximately 20% when the resin was of high Formaldehyde content. The highest reduction ability of basic dyes corresponded to the dye that has the greatest amount of amino residues amenable to reaction with Formaldehyde (Basic Orange 2). Basic Orange 2 dye exhibited higher reduction ability (90% of reduction in leathers treated with resin of high Formaldehyde content after 90 days of leather processing) than the Acid Black 234 dye (approximately 20%), both containing similar amount of free amino residues. Thin layer chromatography analysis revealed that the Basic Orange 2 dye is mainly a single major component, while the Acid Black dye 234 is a mixture of components that can have a reduced reactivity with Formaldehyde. Further experiments are required to investigate if the surface leather dyeing (Basic Orange 2 dye) have a higher influence on Formaldehyde content reduction than the through-dyeing (Acid Black 234 dye).
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Reduction of the Formaldehyde content in leathers treated with Formaldehyde resins by means of plant polyphenols
Journal of Cleaner Production, 2017Co-Authors: Agustí Marsal, Sara Cuadros, Fernando Izquierdo, Albert M. Manich, Joaquim FontAbstract:Formaldehyde has applications in many industrial processes, including synthesis of resins and syntans to be used in the retanning process of leather. When resins are employed, they can hydrolyse, releasing Formaldehyde. Due to the carcinogenicity of Formaldehyde, its presence in leather should be avoided or kept below allowable limits. The aim of this study is to determine the effect of polyphenols contained in vegetable compounds (mimosa, quebracho and tara) in the reduction of the Formaldehyde content in leathers treated with resins synthesized with Formaldehyde (melamine-Formaldehyde and dicyandiamide-Formaldehyde). The Formaldehyde content in leathers treated only with resin increases with time while the Formaldehyde content in leathers treated additionally with vegetable compounds is reduced. The lower the Formaldehyde content in the leather, the higher the ability of vegetable compounds to reduce such content. Mimosa shows the strongest ability to reduce the Formaldehyde content, and this capacity increases with ageing. The addition of 4% (on shaved wet-blue weight) of mimosa gives rise to an 85% reduction in the Formaldehyde content 140 days after leather processing of split hides treated with a Formaldehyde resin of low Formaldehyde content. However, this reduction is 68% in splits hides treated with a resin of high Formaldehyde content. This is of great importance in baby's leather articles, in which the Formaldehyde content is low; therefore, the addition of a small amount (3%) of vegetable compounds (especially mimosa) guarantees that the Formaldehyde content is below the allowed limits (16 mg/kg in the most restrictive regulation). Reducing the Formaldehyde content using the polyphenols contained in vegetable compounds constitutes a good alternative not only in the leather sector but also in other industrial sectors (wood, textile, etc.) that use Formaldehyde resins.
Stephen S. Hecht - One of the best experts on this subject based on the ideXlab platform.
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Reactions of Formaldehyde plus acetaldehyde with deoxyguanosine and DNA: Formation of cyclic deoxyguanosine adducts and Formaldehyde cross-links
Chemical Research in Toxicology, 2003Co-Authors: Guang Cheng, Yongli Shi, John R. Jalas, Edward J. Mcintee, Shana J. Sturla, Peter W Villalta, Mingyao Wang, Stephen S. HechtAbstract:We investigated the reactions of Formaldehyde plus acetaldehyde with dGuo and DNA in order to determine whether certain 1,N(2)-propano-dGuo adducts could be formed. These adducts-3-(2'-deoxyribosyl)-5,6,7,8-tetrahydro-8-hydroxypyrimido[1,2-a]purine-(3H)-one (1) and 3-(2'-deoxyribosyl)-5,6,7,8-tetrahydro-6-hydroxypyrimido[1,2-a]purine-(3H)-one (3a,b)-have been previously characterized as products of the reaction of acrolein with dGuo and DNA. Adduct 1 predominates in certain model lipid peroxidation systems [Pan, J., and Chung, F. L. (2002) Chem. Res. Toxicol. 15, 367-372]. We hypothesized that this could be due to stepwise reactions of Formaldehyde and acetaldehyde with dGuo, rather than by reaction of acrolein with dGuo. The results demonstrated that adducts 1 and 3a,b were relatively minor products of the reaction of Formaldehyde and acetaldehyde with dGuo and that there was no selectivity in their formation. These findings did not support our hypothesis. However, substantial amounts of previously unknown cyclic dGuo adducts were identified in this reaction. The new adducts were characterized by their MS, UV, and NMR spectra as diastereomers of 3-(2'-deoxyribosyl)-6-methyl-1,3,5-diazinan[4,5-a]purin-10(3H)-one (10a,b). Adducts 10a,b were apparently formed by addition of Formaldehyde to N1 of N(2)-ethylidene-dGuo, followed by cyclization. An analogous set of four diastereomers of 3-(2'-deoxyribosyl)-6,8-dimethyl-1,3,5-diazinan[4,5-a]purin-10(3H)-one (12a-d) were formed in the reactions of acetaldehyde with dGuo. These products are the first examples of exocyclic dGuo adducts of the pyrimido[1,2-a]purine type in which an oxygen atom is incorporated into the exocyclic ring. Formaldehyde-derived adducts were the other major products of the reactions of Formaldehyde plus acetaldehyde with dGuo. Prominent among these were N(2)-hydroxymethyl-dGuo (9) and the cross-link di-(N(2)-deoxyguaonosyl)methane (13). We did not detect adducts 1, 3a,b, or 10a,b in enzymatic hydrolysates of DNA that had been allowed to react with Formaldehyde plus acetaldehyde. However, we did detect substantial amounts of the Formaldehyde cross-links di-(N(6)-deoxyadenosyl)methane (17), with lesser quantities of (N(6)-deoxyadenosyl-N(2)-deoxyguanosyl)methane (18), di-(N(2)-deoxyguanosyl)methane (13), and N(6)-hydroxymethyl-dAdo (19). Schiff base adducts of Formaldehyde and acetaldehyde were also detected in these reactions. These results demonstrate that the reactions of Formaldehyde plus acetaldehyde with dGuo are dominated by newly identified cyclic adducts and Formaldehyde-derived products whereas the reactions with DNA result in the formation of Formaldehyde cross-link adducts. The carcinogens formaldehdye and acetaldehyde occur in considerable quantities in the human body and in the environment. Therefore, further research is required to determine whether the adducts described here are formed in animals or humans exposed to these agents.
Agustí Marsal - One of the best experts on this subject based on the ideXlab platform.
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Dyestuffs and Formaldehyde content in split leather treated with Formaldehyde resins
Dyes and Pigments, 2018Co-Authors: Agustí Marsal, Sara Cuadros, Joaquim Font, Rosa M. Cuadros, Albert M. ManichAbstract:Abstract Formaldehyde resins are present in textile, leather and wood industries. Due to the harmful character of Formaldehyde, different alternatives have been found to exclude or reduce its content on processed goods. However, the effect of dyestuffs on the Formaldehyde content of goods containing Formaldehyde-synthesized resins has not been studied up to date. The aim of this work is to check if the presence of free amino groups in the structure of dyestuffs exerts an influence on the Formaldehyde content on leathers treated with Formaldehyde-synthesized resins. Six dyes, belonging to three different families (acid dyes, direct dyes and basic dyes), have been taken as examples to evaluate how their structures affect the reaction with Formaldehyde present in leather. The variation of the Formaldehyde content in dyed leathers with respect to control samples (treated with resin only) and its evolution with time have been also considered. It has been found that the ability of dyes in reducing the Formaldehyde content in leather depends on the amount of amino groups amenable to reaction with Formaldehyde. Those amino groups that in their vicinity have other functionalities, with which to form relatively stable structures, have a reduced reactivity with Formaldehyde. The reduction ability of dyes also depends on the Formaldehyde content in leather. The lower the Formaldehyde content is in the leather, the higher this reduction ability. Acid Black 234 dye caused a Formaldehyde content reduction of approximately 84% in leathers treated with melamine-Formaldehyde resin of low Formaldehyde content in the analysis carried out after 90 days of leather processing whereas the reduction was approximately 20% when the resin was of high Formaldehyde content. The highest reduction ability of basic dyes corresponded to the dye that has the greatest amount of amino residues amenable to reaction with Formaldehyde (Basic Orange 2). Basic Orange 2 dye exhibited higher reduction ability (90% of reduction in leathers treated with resin of high Formaldehyde content after 90 days of leather processing) than the Acid Black 234 dye (approximately 20%), both containing similar amount of free amino residues. Thin layer chromatography analysis revealed that the Basic Orange 2 dye is mainly a single major component, while the Acid Black dye 234 is a mixture of components that can have a reduced reactivity with Formaldehyde. Further experiments are required to investigate if the surface leather dyeing (Basic Orange 2 dye) have a higher influence on Formaldehyde content reduction than the through-dyeing (Acid Black 234 dye).
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Reduction of the Formaldehyde content in leathers treated with Formaldehyde resins by means of plant polyphenols
Journal of Cleaner Production, 2017Co-Authors: Agustí Marsal, Sara Cuadros, Fernando Izquierdo, Albert M. Manich, Joaquim FontAbstract:Formaldehyde has applications in many industrial processes, including synthesis of resins and syntans to be used in the retanning process of leather. When resins are employed, they can hydrolyse, releasing Formaldehyde. Due to the carcinogenicity of Formaldehyde, its presence in leather should be avoided or kept below allowable limits. The aim of this study is to determine the effect of polyphenols contained in vegetable compounds (mimosa, quebracho and tara) in the reduction of the Formaldehyde content in leathers treated with resins synthesized with Formaldehyde (melamine-Formaldehyde and dicyandiamide-Formaldehyde). The Formaldehyde content in leathers treated only with resin increases with time while the Formaldehyde content in leathers treated additionally with vegetable compounds is reduced. The lower the Formaldehyde content in the leather, the higher the ability of vegetable compounds to reduce such content. Mimosa shows the strongest ability to reduce the Formaldehyde content, and this capacity increases with ageing. The addition of 4% (on shaved wet-blue weight) of mimosa gives rise to an 85% reduction in the Formaldehyde content 140 days after leather processing of split hides treated with a Formaldehyde resin of low Formaldehyde content. However, this reduction is 68% in splits hides treated with a resin of high Formaldehyde content. This is of great importance in baby's leather articles, in which the Formaldehyde content is low; therefore, the addition of a small amount (3%) of vegetable compounds (especially mimosa) guarantees that the Formaldehyde content is below the allowed limits (16 mg/kg in the most restrictive regulation). Reducing the Formaldehyde content using the polyphenols contained in vegetable compounds constitutes a good alternative not only in the leather sector but also in other industrial sectors (wood, textile, etc.) that use Formaldehyde resins.
Pieter Jan Coenraads - One of the best experts on this subject based on the ideXlab platform.
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Formaldehyde releasers in cosmetics relationship to Formaldehyde contact allergy part 2 patch test relationship to Formaldehyde contact allergy experimental provocation tests amount of Formaldehyde released and assessment of risk to consumers allergi
Contact Dermatitis, 2010Co-Authors: Anton C. De Groot, Mari-ann Flyvholm, Gerda Lensen, Ian R White, Pieter Jan CoenraadsAbstract:: This is the second part of an article on Formaldehyde-releasers in cosmetics. The patch test relationship between the releasers in cosmetics to Formaldehyde contact allergy is reviewed and it is assessed whether products preserved with Formaldehyde-releasers may contain enough free Formaldehyde to pose a threat to individuals with contact allergy to Formaldehyde. There is a clear relationship between positive patch test reactions to Formaldehyde-releasers and Formaldehyde contact allergy: 15% of all reactions to 2-bromo-2-nitropropane-1,3-diol and 40-60% of the reactions to the other releasers are caused by a reaction to the Formaldehyde in the test material. There is only fragmented data on the amount of free Formaldehyde in cosmetics preserved with Formaldehyde donors. However, all releasers (with the exception of 2-bromo-2-nitropropane-1,3-diol, for which adequate data are lacking) can, in the right circumstances of concentration and product composition, release >200 p.p.m. Formaldehyde, which may result in allergic contact dermatitis. Whether this is actually the case in any particular product cannot be determined from the ingredient labelling. Therefore, we recommend advising patients allergic to Formaldehyde to avoid leave-on cosmetics preserved with quaternium-15, diazolidinyl urea, DMDM hydantoin, or imidazolidinyl urea, acknowledging that many would tolerate some products.
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Formaldehyde-releasers: relationship to Formaldehyde contact allergy. Contact allergy to Formaldehyde and inventory of Formaldehyde-releasers
Contact Dermatitis, 2009Co-Authors: Anton C. De Groot, Torkil Menné, Mari-ann Flyvholm, Gerda Lensen, Pieter Jan CoenraadsAbstract:This is one of series of review articles on Formaldehyde and Formaldehyde-releasers (others: Formaldehyde in cosmetics, in clothes and in metalworking fluids and miscellaneous). Thirty-five chemicals were identified as being Formaldehyde-releasers. Although a further seven are listed in the literature as Formaldehyde-releasers, data are inadequate to consider them as such beyond doubt. Several (nomenclature) mistakes and outdated information are discussed. Formaldehyde and Formaldehyde allergy are reviewed: applications, exposure scenarios, legislation, patch testing problems, frequency of sensitization, relevance of positive patch test reactions, clinical pattern of allergic contact dermatitis from Formaldehyde, prognosis, threshold for elicitation of allergic contact dermatitis, analytical tests to determine Formaldehyde in products and frequency of exposure to Formaldehyde and releasers. The frequency of contact allergy to Formaldehyde is consistently higher in the USA (8-9%) than in Europe (2-3%). Patch testing with Formaldehyde is problematic; the currently used 1% solution may result in both false-positive and false-negative (up to 40%) reactions. Determining the relevance of patch test reactions is often challenging. What concentration of Formaldehyde is safe for sensitive patients remains unknown. Levels of 200-300 p.p.m. free Formaldehyde in cosmetic products have been shown to induce dermatitis from short-term use on normal skin.
