Pyrovatex CP Research Articles

Flame-Retardance Functionalization of Jute and Jute-Cotton Fabrics.

Jute is a ligno-cellulosic natural fiber that ranks second in terms of the volume of cellulosic fibers and is extensively utilized for technical textile applications. The goal of this study is to determine the flame-retardance (FR) properties of pure Jute and Jute-Cotton fabrics treated with Pyrovatex CP New at concentrations of 90% (owf), M:L: 1:7. Both fabrics exhibited a substantial improvement in flame-retardancy. After the ignition period, the recorded flame spread time in both FR treated fabrics was zero seconds; whereas for untreated Jute and Jute-Cotton fabrics, the flame spread time was measured 21 s and 28 s, respectively, to burn their entire length (15 cm). Within these flame-spread times, the length of the char was 2.1 cm and 2.57 cm in the Jute and Jute-Cotton fabrics, respectively. After FR finishing, on both fabrics in the warp and weft directions, the physico-mechanical properties significantly decreased. The deposition of flame-retardant finishes on the fabric surface was determined by Scanning Electron Microscope (SEM) images. According to Fourier Transform Infra-Red Spectroscopy (FTIR) analysis, the flame-retardant chemical had no effect on the inherent properties of the fibers. Thermogravimetric analysis (TGA) analysis revealed that FR treated fabrics had early degradation, resulting in the formation of more char than in the untreated samples. After FR treatment, both fabrics showed a significant improvement in residual mass (more than 50%). Although the formaldehyde content observed in the FR treated samples was significantly greater, it was still within the permitted limit formaldehyde content in textiles intended for outerwear and not worn next to the skin. The results of this investigation demonstrate the potential use of Pyrovatex CP New in jute-based materials.

Sustainable flame retardant treatment for cotton fabric using non formaldehyde cross linking agent

Most flame-retardant finishing agents have been found to have an adverse effect on our environment and human skin because of the carcinogenic chemicals in their structure. Pyrovatex CP New is an Organophosphorus based flame retardant (FR) agent widely used in FR treatment of combustible. However, the main problem related to it is the release of high formaldehyde content (a known carcinogen). When used with methylated melamine (MM) an effective cross-linker. The objective of this research was to use citric acid (CA) and its integration with sodium hypophosphite (NaH2PO2) and two different co-catalyst Titanium dioxide (TiO2) and phosphoric acid (PA) as a flame‐retardant finishing for cotton fabrics. The flammability of cotton fabric was assessed by a manual vertical flammability test, it is found that the combination of co-catalysts in FR formulation lowers the flammability of cotton. The pyrolysis characteristics and char residue yield of the treated cotton shows that the flame retardancy improves as the amount of catalyst is increased. The whiteness index, crease recovery and tensile strength of the treated cotton fabric was also significantly improved with our suggested recipe formulation. The finished cotton has significant variations in terms of its tensile strength, crease recovery, and whiteness index.

Optimizing content of Pyrovatex CP New and Knittex FFRC in flameretardant treatment for cotton fabric

In this study, the flame-retardant treatment for cotton fabric has been done by using the commercial organophosphoruscompounds labelled Pyrovatex CP New (PR). Knittex FFRC (K), a formaldehyde-free crosslinking agent, has been usedto enhance the link between Pyrovatex CP New and Cellulose molecules. The flame-retardant treatment process forcotton fabric has been done by the pad-dry-cure technique. The purpose of the study is to predict the optimal PyrovatexCP New and Knittex FFRC concentrations with the highest fire resistance efficiency, minimum loss for mechanicalproperties and minimum formaldehyde release for the treated fabric. To achieve this goal, the response surfacemethodology (RSM) was used to find the relationship between the controlled experimental factors and the observedresults. The central composite design type face centred (CCF) was applied as experimental design. According to thisexperimental design, 10 experiments were carried out. The chemical uptake rate, vertical flammability characteristics,LOI value, tensile strength and formaldehyde-free content of the untreated and treated samples were determined. Fourresponse models between the reagent concentrations and the add-on amount, LOI value, warp and weft tensile strengthof the treated fabric were obtained by the assistance of software Design-Expert V 10.0.8. The R-squared values of thesemodels were above 80% confirming their significances. The optimal conditions when combining three parameters (LOI,warp tensile strength and weft tensile strength) were selected as 450 g/l Pyrovatex CP New and 107,575 g/l KnittexFFRC with the assistance of Design-Expert software

Application of Plasma Activation in Flame-Retardant Treatment for Cotton Fabric.

Cotton fabric treated by Pyrovatex CP New (PCN) and Knittex FFRC (K-FFRC) using the Pad-dry-cure method showed an excellent fire-retardant effect. However, it needed to be cured at high temperatures for a long time leading to a high loss of mechanical strength. In this study, atmospheric-pressure dielectric barrier discharge (APDBD) plasma was applied to the cotton fabric, which then was treated by flame retardants (FRs) using the pad–dry-cure method. The purpose was to have a flame-retardant cotton fabric (limiting oxygen index (LOI) ≥ 25) and a mechanical loss of the treated fabric due to the curing step as low as possible. To achieve this goal, 10 experiments were performed. The vertical flammability characteristics, LOI value and tensile strength of the treated fabrics were measured. A response model between the LOI values of the treated fabric and two studied variables (temperature and time of the curing step) was found. It was predicted that the optimal temperature and time-to-cure to achieve LOI of 25 was at 160 °C for 90 s, while the flame-retardant treatment process without plasma pretreatment, was at 180 °C and 114 s. Although the curing temperature and the time have decreased significantly, the loss of mechanical strength of the treated fabric is still high. The tensile strength and scanning electron microscopy (SEM) images of the fabric after plasma activation show that the plasma treatment itself also damages the mechanical strength of the fabric. X-ray photoelectron spectroscopy (XPS) spectra of the fabric after plasma activation and energy-dispersive spectroscopy (EDS) analysis of the flame retardant-treated (FRT) fabric clarified the role of plasma activation in this study.

Preparation and characterization of polyvinyl alcohol/sodium alginate/Pyrovatex CP composite fibers

Pyrovatex CP which was used as a flame retardant was added into polyvinyl alcohol (PVA) and sodium alginate (SA) aqueous solution. PVA/SA composite fibers modified with Pyrovatex CP (PSC) were prepared by wet spinning. It was characterized by FT-IR, SEM and TG. The results showed that Pyrovatex CP reacted with hydroxyl groups of PVA and SA. The breaking strength of PSC was slightly improved and the elongation at break of PSC increased rapidly. The flame retardancy and thermal stability of PSC were characterized by limiting oxygen index (LOI) and thermogravimetric analysis, respectively. The results showed that when Pyrovatex CP was 33 wt%, the elongation at break and LOI of PSC were 66.29% and 30.4%, respectively. The residue of the PSC at 600 °C is 27%.

OPTIMIZING CURING CONDITIONS IN FLAME RETARDANT TREATMENT FOR COTTON FABRIC

The study of the influence of curing conditions on the properties of the cotton fabric treated with Pyrovatex CP New (PR) and Knittex FFRC was carried out with 10 experiments. The central composite designs type face centered (CCF) was used to design experiments. In these experiments, the curing temperature was varied from 160o C to 180o C and the curing time from 60-120 seconds. The chemical uptake rate, vertical flammability characteristics, LOI value, tensile strength of the untreated and treated samples were determined. Based on the results, 5 response models between the determined properties of the treated fabric and two studied variables were found. From these models, the optimal curing temperature and time were found with the highest fire resistance efficiency and minimum loss for the mechanical properties. They are 180o C and 113.7 seconds

Influence of crosslinking agent on the effectiveness of flame retardant treatment for cotton fabric

In this study, the commercial organophosphorus compound Pyrovatex CP New was used as a flame retardant for cotton fabric. Citric acid and a modified dihydroxy ethylene urea (DHEU) labelled Knittex FFRC were used as crosslinking to increase the flame-retardant laundering durability of treated cotton fabric. There have been some studies showing that Chitosan has the potential to improve flame retardancy and laundering durability of flame retardant treated cotton fabric. Thus, Chitosan, which has the molecular weight of 2.600 (water soluble) and the deacetylation degree of approximately 75%, is added to finishing solution for flame retardant treatment of cotton fabric. The padding-drying-curing method was used in this study. After treatment, all samples were examined to determine the chemical absorption level. The 45° flammability test characteristics and LOI value of untreated and treated samples after different number of washing cycle were determined to assess the flame retardancy of the treated fabric and its laundering durability. In addition, to assess the impact of this treatment on the mechanical strength and ecology of the fabric, the tensile strength and free formaldehyde content of the treated fabric were also evaluated

Effect of softener and wetting agent on improving the flammability, comfort, and mechanical properties of flame-retardant finished cotton fabric

Cotton, a commonly used textile material, tends to burn easily. For some specific end-uses, flame-retardant (FR) properties are required. However, this kind of finish tends to worsen the hand feel and strength of the fabric. This study explored the feasibility of applying softener and wetting agent during flame-retardant treatment of cotton fabrics to improve their comfort and mechanical properties. Here, flame-retardant agent Pyrovatex CP New, crosslinking agent Knittex CHN, and phosphoric acid were combined with various softeners and wetting agent, and applied to the fabrics using a pad–dry–cure process. Fabric combustibility was evaluated by 45° flammability test. The thermal decomposition behavior and chemical structure of the samples were characterized by thermogravimetric analysis and Fourier-transform infrared spectroscopy, respectively. The thermophysiological comfort properties, hand, and mechanical properties of the fabrics were additionally measured. The results demonstrated that FR-treated cotton specimens had lower strength and poor fabric hand and wettability, which might be caused by formation of crosslinks due to the acidic reaction condition and high curing temperature. Meanwhile, softener addition could compensate for these drawbacks and remarkably improve fabric hand and strength. On the other hand, addition of wetting agents could improve the flame resistance of the FR-treated fabrics.

Synthesis and application of a sulfur‐containing phosphoric amide flame retardant for nylon fabric

SummaryA sulfur‐containing flame retardant (SFR) was synthesized from polyphosphoric acid, epoxy chloropropane, and thiourea. Using a water‐soluble isocyanate‐terminated (WIT) cross‐linker, the flame retardant was applied as a flame‐retardant finishing on nylon fabric. WIT is a compound that not only cross‐links SFR and nylon cellulose but also contains no formaldehyde. Comparisons of the main performances of SFR with those of N‐methyloldimethylphosphonopropionamide (known as ‘Pyrovatex CP’) and a bicyclic phosphonite (known as ‘Antiblaze 19T’) indicate that the presence of sulfur in SFR plays a crucial role in decreasing the flammability of the nylon fabric. The limiting oxygen index value and damaged carbon length of the finished nylon fabric were 29.4% and 5.7 cm, respectively, when the concentrations of SFR and WIT were 200 and 40 g/L, respectively, and the baking temperature and time were 150 °C and 3 min, respectively. After 10 laundry cycles, the fabric still retains some flame retardancy. Copyright © 2016 John Wiley & Sons, Ltd.

Synthesis of 2, 3-dibromo-succinic anhydride and application on cotton, polyester and polyester/cotton blended fabric

For a poly(ethylene terephthalate) (PET)/cotton blended fabric, a reactive-type flame retardant 2, 3-dibromo-succinic anhydride (DBSA) was used to endow durable flame retardancy via the pad-dry-cure method. DBSA was synthesized via the addition reaction of maleic anhydride and bromine in ethyl acetate solution and extracted by solventing-out crystallization. DBSA was used to finish a cotton fabric firstly with sodium hypophosphite as the catalyst. Thermal behaviors and amount of DBSA that esterified with the cotton was determined. Pyrovatex CP new was applied as a comparison. It was speculated from the thermogravimetric analysis result that esterification of cellulose with DBSA worked similar to phosphate-ester at the initial stage of thermal decomposition. DBSA was also applied to PET and PET/cotton blended fabrics. Flame retardancy, thermal behaviors and durability of the finished fabrics were investigated. Evidence of the condensed phase effect of DBSA was also observed on PET and PET/cotton.

Citric acid based durable and sustainable flame retardant treatment for lyocell fabric

Pyrovatex CP New, is a commonly used organophosphorus based flame retardant (FR) reagent for cellulosic materials. However, it has a drawback of high formaldehyde release when used with methylated melamine (MM) based cross-linker, a known carcinogenous compound. In the present approach, a durable and sustainable flame retarding recipe formulation for lyocell fabrics is developed using citric acid (CA) as a cross-linker. The FR finish was applied by pad-dry-cure process. The treated fabrics were characterized for surface morphology, elemental analysis, TG analysis, char study and FT-IR spectroscopy. Furthermore, flame retardancy, washing durability, formaldehyde release and breaking strength were also assessed, and compared with the conventional MM based FR recipe. The fabric samples treated with 400gL−1 of FR with either 40 or 80gL−1 of CA demonstrate flame retardancy even after 10 washing cycles. Furthermore, a 75% reduction in formaldehyde release is achieved. Higher char yield and lower decomposition temperature are found compared to untreated and FR+ MM treated lyocell. Such an improved sustainable recipe formulation can be used for lyocell fabric without any health risk in apparel wear.

Effects of TiO₂ and curing temperatures on flame retardant finishing of cotton.

The performance of flame retardancy of cotton cellulose can be influenced by curing conditions. In this study, cotton cellulose was imparted durable flame retardant properties by a reaction between a flame retardant agent (Pyrovatex CP New) and a cross linking agent (Knittex CHN), in the presence of catalysts phosphoric acid and titanium dioxide (TiO2). After treating cotton fabrics at different curing temperatures for different curing time, its flame retardant performance was evaluated by 45° fabric flammability standard test method. For cotton fabrics cured at 150 and 170°C, good flame retardant characteristics were retained even after three home laundering cycles. The use of TiO2 as a co-catalyst in the treatment improved the flame retardant properties and reduced the loss of tearing strength of cotton fabrics. No significant negative effect in the whiteness index was observed, as compared with conventional flame retardant treatment.

Objective measurement of hand properties of plasma pre-treated cotton fabrics subjected to flame-retardant finishing catalyzed by zinc oxide

In the present paper, flame resistance property is imparted to cotton fabrics by N-methylol dimethylphos-phonopropionamide (Pyrovatex CP New, FR), melamine resin (Knittex CHN, CL), phosphoric acid catalyst (PA), and ZnO/nano-ZnO co-catalyst. The study shows that effectiveness of the FR-CL-PA reaction to form a crosslinked structure is enhanced by the co-catalytic reaction, resulting in enhancement of fabric’s compressional recovering ability. However, the low pH reaction weakened the fabrics, resulting in poor tensile strength and toughness, stiffer hand feel, brittle and tendered polymer layers, a less spongy fabric structure, and a roughened fabric surface with fuzzy fibrils. In addition, atmospheric pressure plasma jet (APPJ) was used to enhance materials properties by sputtering or etching effect. The roughening effect of plasma treatment enhances tensile properties of treated specimens. Nevertheless, the positive effect is negligible after post-treatment with flame-retardant agents. Moreover, the increased inter-yarn friction enhances the subjective stiffness of fabric and the rigid effect is even worse for plasma pre-treated cotton specimens subjected to flame-retardant treatment. However, plasma pre-treated specimens have a compressible structure after post-treatment with flame-retardant agents. Moreover, neutralization of flame-retardant-treated specimens helps minimize side effects of acidic finishing, irrespective of tensile and compression properties. The process also minimizes shear and bending rigid effect by removing unattached metal oxides from the fabrics.

A durable flame retardant for cellulosic fabrics

A novel halogen- and formaldehyde-free flame retardant named Neo-FR was synthesized and applied to cellulosic fabrics. The chemical structure of the flame retardant was characterized by Fourier-transform infrared spectroscopy (FTIR). The flame retardant performance was evaluated by Limiting oxygen index (LOI) and vertical flammability tests. The results indicated that the flame retardant had excellent flame retardancy and durability for cellulosic fabrics. The surface morphology of treated fibre and fibre char residue were observed through scanning electron microscope (SEM). The SEM graphs demonstrated that the Neo-FR system played intumescent flame retarding mechanism on cotton fibre. The thermal property of the flame retardant treated cotton fabric was investigated through thermal gravimetric analysis (TGA). The results indicated that char residue of the treated fabrics was about 36.5%, which was much higher than that of untreated fabric. The mechanical properties such as tensile strength and elongation of the cotton samples treated with Neo-FR system were much less affected than those treated by a commercial durable flame retardant agent (Pyrovatex CP New). The laundering test results show that the Neo-FR system is a durable flame retardant for cellulosic fabrics.

The Durability of Flame Retardant and Thermal Protective Cotton Fabrics during Domestic Laundering

Flame retardant fabrics have been broadly used for protective clothing, which have strictly requirements on both flame retardancy and thermal protection. Usually, domestic laundering will be carried out frequently to clean these protective garments. However, little research on the performance durability of this type of fabrics after domestic laundering has been reported. This paper selected fabrics of 8 types of cotton and its blend fibers, which were treated with flame retardants Pyrovatex CP, Proban, CFR-201, SCJ-968 respectively. The damaged length, after flame time, after glow time, TPP value, thermal resistance value, weight, thickness, air permeability and water vapor permeability (WVP) of the samples were measured before and after 15 cycles domestic laundering cycles. Results show that the flame retardancy of the 8 fabrics reduce with launderings as measured by the increase in damaged length and after glow time. The TPP increase probably resulted from the increase in the thickness and thermal resistance of the finished fabrics. Domestic laundering resulted in only a slight change in the comfort properties of the fabrics.

Effect of titanium dioxide on the flame‐retardant finishing of cotton fabric

AbstractIn this study, titanium dioxide (TiO2) or nano titanium dioxide (nano‐TiO2) was used as a cocatalyst in the flame‐retardant (FR) formulation of N‐methylol dimethylphosphonopropionamide (Pyrovatex CP New, FR), melamine resin [Knittex CHN, crosslinking agent (CL)], and phosphoric acid (PA) for cotton fabrics to improve the treatment effectiveness and minimize the side effects of the treatment. For FR‐treated cotton fabrics, the flame extinguished right after removal of the ignition source with no flame spreading. However, after neutralization and/or home laundering, FR–CL‐treated specimens failed the flammability test, whereas the opposite results were obtained from FR–CL–PA‐treated specimens. A noticeable result was that the TiO2/nano‐TiO2 cocatalyst had a significant effect on decreasing the flame‐spread rate. Thermal analysis found that the FR‐treated specimens without wet posttreatment showed two endothermic peaks representing the phosphorylation of cellulose and acid‐catalyzed dehydration. In addition, the treated fabrics showed some new characteristic peaks in their chemical structures; these were interpreted as carbonyl bands, CH2 rocking bands, and CH3 asymmetric and CH2 symmetric stretching. The surface morphology of the FR–CL–PA‐treated cotton specimens showed a roughened and wrinkled fabric surface with a high deposition of the finishing agent that had a lower breaking load and tearing strength, which resulted from the side effects of the CL used. However, the addition of a TiO2 or nano‐TiO2 cocatalyst could compensate for the reduction in the tensile strength. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Flame‐retardant properties of soybean fabric modified with N‐methylol diakyl phosphonopropionamide

AbstractSoybean is a competitive production material for fibers as it is abundant and cost effective. However, an inherent deficiency of soybean fiber is its poor flame‐retardant performance. In this study, the effect of N‐methylol diakyl phosphonopropionamide (Pyrovatex CP) on the flame retardancy of soybean was investigated by the Limiting Oxygen Index (L.O.I.) and the vertical flammability test. Little benefit with regard to flame retardancy was found when soybean was treated with Pyrovatex CP in the absence of additives. However, the incorporation of Lyofix MLF in the finishing treatment (3% w/v) increased the L.O.I. values of soybean fiber and enhanced char formation as indicated by Thermogravimetric Analysis (TGA). Improved fastness to washing was observed at higher application levels of Lyofix MLF (6% w/v). X‐ray Photoelectron Spectroscopy (XPS) indicated that surface phosphorus (% atomic) was reduced following washing for all fabrics examined. In addition, the substantivity of Lyofix MLF to soybean surface was exhibited. The flame‐retardant treatment presented in this article is cost effective and results in wash‐durable flame‐retardant fabrics. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

The application of a novel flame retardant on viscose fiber

AbstractThe paper is mainly about a novel organophosphorus flame‐retardant N‐1‐chloroisopropyl alcohol‐3‐dimethylphosphonopropionamide. Dimethyl phosphate, acrylamide and epichlorohydrin were used as raw materials. The mechanisms of synthesis and molecule structure of the flame retardant were discussed. The fiber was treated using the pad‐dry‐cure‐wash method. The limiting oxygen index value of the modified sample was 31%, higher than that of the sample treated with MDPA (Pyrovatex CP). After 50 laundry cycles, it still had some flame retardancy left. Thermogravimetry (TG) and Differentiate TG analyses confirmed that the flame retardant caused fiber to decompose below its ignition temperature and formed carbonaceous residue or char when exposed to fire. The treatment had an obvious effect on the denier of the fiber; the tensile strength of fiber slightly decreased, but that effect could be negligible. Copyright © 2008 John Wiley & Sons, Ltd.

Effect of phosphorus flame retardants on thermo-oxidative decomposition of cotton

The effect of six organophosphorus compounds, including Pyrovatex CP (PCP), diammonium phosphate (DAP), phosphoric acid (PA), tributyl phosphate (TBP), triallyl phosphate (TAP) and triallyl phosphoric triamide (TPT) on the flame retardancy of cotton cellulose was studied. PCP, PA, and DAP are more efficient compared with the other three compounds in improving the limiting oxygen index (LOI) of cotton. The effectiveness of these compounds was investigated using scanning electron microscope (SEM) images of char formed after LOI tests, char content, activation energy of decomposition and heat of combustion data. SEM images showed that DAP, PCP and PA chars maintain the surface morphology during the burning process, which might be due to the formation of a protective layer or crosslinking effect. PA, PCP, and DAP treated fabrics have a higher activation energy of decomposition, higher char content and lower heat of combustion.

Comparison of different reactive organophosphorus flame retardant agents for cotton: Part I. The bonding of the flame retardant agents to cotton

N-Methylol dimethylphosphonopropionamide (MDPA), known as “Pyrovatex CP” and “Pyrovatex CP New” commercially, has been one of the most commonly used durable flame retardant agents for cotton for many years. In our previous research, we developed a flame retardant finishing system for cotton based on a hydroxy-functional organophosphorus oligomer (HFPO) in combination with a bonding agent such as trimethylolmelamine (TMM) and dimethyloldihydroxyethyleneurea (DMDHEU). In this research, we investigated the bonding of these two flame retardant finishing agents to cotton. We found that the majority of MDPA is bound to cotton by its N-methylol group and that the use of TMM as a co-reactant modestly increases the fixation of MDPA onto cotton. For HFPO, however, the use of a bonding agent is necessary to form a covalent linkage between HFPO and cotton. Both the fixation of HFPO on cotton and its laundering durability are influenced by the effectiveness and concentration of the bonding agent. The commercial product of HFPO contains approximately 33% more phosphorus than that of MDPA and the percent fixation of HFPO on cotton is also moderately higher than that of MDPA. The bonding between MDPA and cotton is significantly more resistant to hydrolysis during multiple launderings than that between HFPO and cotton. The selection of catalyst also plays a significant role in influencing the bonding of the flame retardant agents to cotton.