DEVELOPMENT OF NEW NONFORMALDEHYDE FLAME RETARDANT FINISHING TECHNOLOGY FOR COTTON FLEECE

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 0220664
• Project Start Date: Oct 20, 2009
• Project End Date: Jul 31, 2013
• Program Code: [(N/A)]- (N/A)

Recipient Organization
UNIVERSITY OF GEORGIA
200 D.W. BROOKS DR
ATHENS,GA 30602-5016

Performing Department
College of Family & Consumer Sciences

Non Technical Summary
Federal government in the United States strictly regulates the flammability of textiles, including wearing apparel, children's sleepwear, upholstered furniture, carpet and rugs. Flame retardant finishing is an area of fast growth as the safety of consumers becomes a focus of public attention. Consumer Product Safety Commission (CPSC) is the federal agency that enforces the federal regulations related to flammability of textiles2. The flammability of all clothing textiles is regulated under "CFR 16 CFR 1610: Standard for the Flammability of Clothing Textiles"2. Cotton is one of the most flammable fibers. Raised surface and lightweight apparel fabrics are regulated under "General Wearing Apparel Standard" (16 CFR 1610)2. Compared with other fabrics, raised surface fabrics, fleece in particular, have lower density and contain more air in their fuzzy surfaces, therefore have higher flammability. Fleece, a knitted fabric with a napped surface, is more flammable than other raised surface fabrics. Generally, 100% cotton fleece fabrics are not able to meet the 16 CFR 1610 standards without chemical treatment. As a conservative estimate, 80,000,000 pounds of cotton fiber potentially need chemical treatment if new flame retardant finishing technology can insure that those raised surface 100% cotton fabrics will meet the federal flammability standard. This project will develop low cost, highly effective and commercially feasible new chemical finishing technology to treat cotton fleece and other raised surface cotton fabrics.

Animal Health Component

(N/A)

Research Effort Categories

Basic

(N/A)

Applied

(N/A)

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
511	1719	2000	100%

Knowledge Area
511 - New and Improved Non-Food Products and Processes;

Subject Of Investigation
1719 - Cotton, other;

Field Of Science
2000 - Chemistry;

Keywords

cotton

flammability

flame retardant finishing

consumer safety

chemical treatment

Goals / Objectives
(1) We will develop new nonformaldehyde finishing systems for cotton fleece, including the traditional organophosphorus flame retardants and the non-traditional flame retardants based on multifunctional carboxylic acids. The new flame retardant finishing systems should meet the following requirements: a. Nonformaldehyde; b. Being compatible with the traditional textile finishing facilities used by the industry; c. Low cost; d. Durable to 10 laundering. We will also evaluate the feasibility of applying the new flame retardant finishing technology on a commercial scale. (2) We will investigate the mechanism of those new flame retardants to reduce the flammability of cotton fleece and will publish research data in peer-reviewed journals and will give presentations in national and international conferences.

Project Methods
(1) Developing the following three new nonformaldehyde flame retardant systems for cotton fleece: a. The nonformaldehyde flame retardant system comprising HFPO with BTCA as a bonding agent and triethanolamine (TEA) as a reactive additive. Based on our previous research on flame retardant finishing of cotton woven fabric and Nomex/cotton blend fabric,27-29 BTCA is effective for bonding HFPO to cotton and TEA participates in the BTCA's reactions on cotton both to improve HFPO's laundering durability and to providing synergistic nitrogen. b. The nonformaldehyde flame retardant system comprising oligomeric polymaleic acid (OPMA), which contains (~5-10%) phosphorus. Previously, we studied the use of MA to bond hypophosphite to cotton fleece.30 Such treatment is effective in reducing the flammability of cotton fleece, but it courses high fabric strength loss due to the high acidity of MA. The acidity of OPMA is significantly lower than MA whereas its reactivity is similar to that of MA. OPMA is now commercially available and significantly less expensive than HFPO. We expect that treating cotton fleece is able to ensure the fleece to meet the 16CFR1610 flammability standard with satisfactory fabric strength retention and low cost. c. The nonformaldehyde flame retardant system comprising malic acid (MLA) and succinic acid (SA). MLA and SA are among the least expensive and safe commodity chemicals used by the industry. In our previous research, we found that both MLA and SA are effective in reducing the flammability of cotton fleece. We also found that MLA has yellowing effects on bleached cotton fleeces whereas SA has lower solubility in water. In this research, we will investigate the use of the mixture of PLA and SA as flame retardant for cotton fleece to achieve the optimized fabric flammability, fabric physical property, and flame retardants solubility. (2) Studying the mechanism of the three flame retardants on cotton fleece a. Investigation of the mechanism of the flame retardants used for cotton fleece using micro-scale combustion calorimeter. The three types of chemical additives to be investigated in this research are non-traditional flame retardants. Polycarboxylic acids do not show flame retardancy on cotton woven fabrics when the fabrics are tested using the traditional vertical flame flammability and limiting oxygen index (LOI). In this research, we will use our micro-scale combustion calorimeter to measure heat release rate, heat release capacity and total hest release data of the treated fleece, and will correlate the date to the 45 flammability data so that we can have more understanding of the mechanism how those flame retardants suppress the combustion of cotton fleece. b. Investigation of the relationship between the molecular structure and flame retardancy of polycarboxylic acids. We will study and compare the performance of the polycarboxylic acids with different molecular structures as flame retardant agents for cotton fleece so that the relationship between performance and molecular structure for multifunctional carboxylic acid can be established.

Progress 10/20/09 to 07/31/13

Outputs
Target Audience:People who are working on projects related to prouction and uses of cotton-based products in the textile industry, research institutions, government and high education. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest?Major papers were published in highly ranked international journals. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? We successfully accomplished the following previously identified goals:developing new nonformaldehyde finishing systems for cotton fleece as well as other cotton-based textiles and studying the mechanism of those new flame retardants to reduce the flammability of cotton fleece. Wewill published research data in several peer-reviewed journals . Such finishing systemincluded the traditional organophosphorus flame retardants and the non-traditional flame retardants based on multifunctional carboxylic acids. The new flame retardant finishing systemsmet the following requirements: a. nonformaldehyde; b. being compatible with the traditional textile finishing facilities used by the industry; c. low cost; d. durable tomultiple laundering.

Publications

• Type: Journal Articles Status: Published Year Published: 2014 Citation: C. Q. Yang, Crosslinking: A Route to Improve Cotton Performance, AATCC Review, 13 (May/June), 43-52 (2013).

Progress 01/01/11 to 12/31/11

Outputs
OUTPUTS: In 2011, we continued the project by focusing on then investigation of flame retardant finishing of cotton fleece. The use of polycarboxylic acids for the flame retardant finishing of cotton fleece to meet the federal regulation (16 CFR 1610) was a new idea. Our work in this area attracted significant attention and interests. Examples of such interests include high number of citation in the scientific literature. Our previous publication (Cheng, X., and Yang, C. Q. Flame retardant finishing of cotton fleece fabric: Part V. Phosphorus-containing maleic acid oligomers, Fire & Materials, 33, 365-375, 2009), is one of the most highly cited papers on this topic. A Published (Springer) invited me to write a 100-page book on this subject. in a review on flam retardant textiles (Horrocks, A. R., Flame retardant challenges for textiles and fibers: new chemistry versus innovatory solutions, Polym. Degrad. Stab., 96, 377-392, 2011) most of our work on this topic was cited as a genuine development in the area of flame retardant cotton. PARTICIPANTS: In 2011, we focused on the following two areas: (1) Bonding of phosphorus to cotton by the treatment using MA/NaH2PO2. The cotton fabric was treated with MA and NaH2PO2, cured at different temperatures for 2 min and subjected to one home laundering cycle. We found that NaH2PO2 is bound to cotton. It is evident that bonding of NaH2PO2 to cotton requires significantly higher temperature than the esterification of cotton by MA. Phosphorus is an element which functions as an effective condensed phase flame retardant. Thus, bonding NaH2PO2 to cotton significantly reduces the flammability of cotton. (2) The use of MA/NaH2PO2 to reduce the heat release properties of cotton. The heat release rate (HRR) of the cotton fabric treated with MA and cured at different temperatures are studies. Peak HRR (PHRR) is the most important parameter in determining the flammability of a material. The esterification of cotton by MA reduced both HRR and PHRR of cotton. The PHRR of the cotton treated with MA/NaH2PO2 is much lower than that treated with MA alone, which is evidently attributed to the increased quantity of esterification as a result of the presence of NaH2PO2 as the catalyst and also by the bonding of NaH2PO2 to the cotton by its reaction with MA on the cotton. The decrease in PHRR is obviously caused by the bonding of phosphorus, a flame retarding element, to the treated cotton at those elevated curing temperature. Our conclusions are summarized as follows. (1) Esterification of cotton by MA reduces the flammability of the cotton as indicated by decrease in PHRR and increase in percent char yield of the treated cotton fabric. NaH2PO2 catalyses esterification of cotton by MA cotton, thus further reduces the cotton fabric's flammability after its esterification with cotton cellulose. (2) For the cotton fabric treated with MA and NaH2PO2, the bonding of hypophosphite to cotton further enhances the flame retardancy of the MA-treated cotton fabric as indicated by more significant decrease in PHRR and temperature at PHRR (TPHRR), and more significant increase in the char formation. (3) The cotton fleece treated with the combination of MA and sodium hypophosphite is able to achieve the class 1 flammability standard specified by 16 CFR 1610 at low concentrations. TARGET AUDIENCES: Textile finishing industry and scientific community in the area of cellullse modification. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
We have gained new knowledge from the projecct. Federal government in the United States strictly regulates the flammability of all textiles, including wearing apparel, children's sleepwear, upholstered furniture, carpet and rugs. Cotton is one of the most flammable fibers. Generally, 100% cotton fleece fabrics are not able to meet the 16 CFR 1610 standards without chemical treatment. The objective of this project is to develop new nonformaldehyde finishing systems for cotton fleece and the related basic research. In 2011, we studied the use of polycarboxylic acids as the flame retardants for cotton fleece, particularly the combination of maleic acid and sodium hypophosphite form the flame retardant finishing of cotton. We found that (1)esterification of cotton by polycarboxylic acids reduces heat release rate and consequently reduces the flammability of cotton, and (2) bonding hyphophosphite to cotton by the combination of maleic acid and sodium hypophosphite further reduces the flammability of cotton. Such new knowledge will lead to new approach in flame retradant finishing of cotton textiles.

Publications

• Yang, C. Q., He, Q. 2011. and Voncina, B. 2011. Crosslinking of Cotton Cellulose by Maleic Acid in the Presence of Sodium Hypophosphite. Part II. Fabric Fire Performance, Industrial and Engineering Chemistry Research, 50, 5889-5897.
• Yang, C. Q., and He, Q. 2011. Applications of Micro-Scale Combustion Calorimetry to the Studies of Cotton and Nylon Fabrics Treated with Organophosphorus Flame Retardants, Journal of Analytical and Applied Pyrolysis, 91, 125-133.
• Peng, H., Yang, C. Q., and Wang, S. 2012. Nonformaldehyde Durable Press Finishing of Cotton Fabrics Using the Combination of Maleic Acid and Sodium Hypophosphite, Carbohydrate Polymers, 87, 491-499. (Published in 2011).
• ABSTRACTS 2011.
• Yang, C. Q., and He, Q. 2011. Studies of Heat Release Properties of Different Textiles Using Micro-Scale Combustion Calorimetry, Abstracts of the First Central and Eastern European Conference on Thermal Analysis and Calorimetry, Craiova, Romania.
• Yang, C. Q., and Peng, H. 2011. Applications of Maleic Acid and Sodium Hypophosphite as Durable Press Finishing Agents for Cotton Fabrics, Abstract of 11th Autex (Association of the Universities if Textiles) World Textile Conference, Mulhouse, France.
• Yang, C. Q. 2011. New development in Flame Retardant Finishing of Cotton Blends, Abstracts of the 3rd Technical Annual Conference of Guangdong Textile Chemical Auxiliary Industrial Association, Shunde, Guangdong, China.
• Yang, C. Q. 2011. "New development in Flame Retardant Finishing of Cotton Blends", "Proceedings of the 3rd Technical Annual Conference of Guangdong Textile Chemical Auxiliary Industrial Association" (invited key-note speech), Guangdong Textile Chemical Auxiliary Industrial Association, Shunde, Guangdong, China, pp67-83.
• Yang, C. Q., and Peng, H. 2011. "Application of Maleic acid and Sosium hypophosphite as Durable Press Finishing Agent for Cotton Fabrics, "Proceedings of the 11th Autex (Association of the Universities if Textiles) Conference" (CD), Autex, Mulhouse, France, 2011.
• PAPERS IN PROCEEDINGS. 2011.