Total visitors:471 since 18-06-04

Indian Journal of Fibre & Textile Research

 

 ISSN : 0971-0426

 

CODEN : IJFRET

VOLUME 29

NUMBER 2

JUNE 2004

 

CONTENTS

 

A successful weaving trial with a size-free cotton warp

A P S Sawhney, J B Price & T A Calamari

[IPC Code: Int. Cl7. D03D 25/00; D02G 3/00]

 

117

Air and water permeability characteristics of nonwoven fabrics

D Bhattacharjee, A Ray & V K Kothari

[IPC Code: Int. Cl7. D04H 3/00; G01N 15/00]

122

Modification of polyester fabric via radiation grafting with methacrylic acid

Eglal H K El-Gendy

[IPC Code: Int. Cl7. D06M 14/08]

 

129

Woven fabric behaviour during pulling disc-shaped specimen through a central hole

I Saukaityte,V Daukantiene & M Gutauskas

[IPC Code: Int. Cl7. D03D 15/00; G01N 33/36]

 

138

Using drape form to establish discriminant models of fabric characteristics

Lai Sang-Song

[IPC Code: Int. Cl7. D06J 1/00; G01N 33/36]

 

143

Prediction of air-jet textured yarn properties using statistical method and neural network

V K Yadav & V K Kothari

[IPC Code: Int. Cl7. G06N 3/02; D02G 3/00]

 

149

Prediction of single yarn tenacity of ring- and rotor- spun yarns from HVI results using artificial neural networks

Abhijit Majumdar , Prabal Kumar Majumdar & Bijan Sarkar

[IPC Code: Int. Cl7. G06N 3/02; D02G 3/00]

 

157

Tensile behaviour of polyester yarns modified by  solvent-acid mixture pretreatment process

D Chidambaram,  R Venkatraj & P Manisankar

[IPC Code: Int. Cl7. D02G 3/00;  D02J 1/00]

 

163

Study on drafting force of roving: Part I – Effect of process variables

A Das, S M Ishtiaque & Rajesh Kumar

[IPC Code: Int. Cl7. D02G 3/00; D01H 5/00]

 

173

Study on drafting force of roving: Part II – Effect of material variables

A Das, S M Ishtiaque & Rajesh Kumar

[IPC Code: Int. Cl7. D02G 3/00; D01H 5/00]

 

179

Variation in polyester-viscose and polyester-cotton ring- and rotor-yarn characteristics as a consequence of fibre cross-section

G K Tyagi, K R Sharma, A Goyal & Mandeep Singh

[IPC Code: Int. Cl7. D02G 3/00]

 

184

Optimization of ring frame process parameters for better yarn quality and production

S M Ishtiaque, R S Rengasamy & A Ghosh

[IPC Code: Int. Cl7. D01H  1/ 02; D02G 3/00]

 

190

Effect of process parameters at comber on yarn and fabric properties

S Subramanian & N Gobi

[IPC Code: Int. Cl7. D01H 13/00; D02G 3/00; G01N 33/36]

 

196

Fine structure variations of polyester tow at different treatment conditions

J Maillo, D Cayuela, J Gacén, E Estrenjer & A M Sitges

[IPC Code: Int. Cl7. D01G 37/00]

 

200

Influence of cooking and adjustment treatments on reeling and quality characteristics of raw silk

G Hariraj &T H Somashekar

[IPC Code: Int. Cl7. D01B 7/00]

 

207

Utilization of chitosan citrate as crease-resistant and antimicrobial finishing agent for cotton fabric

Aly Sayed Aly  , Ali Hashem & Samaha Sayed Hussein

[IPC Code: Int. Cl7. D06C 29/00; D06B 3/00]

 

218

Efficacy of selective surfactants / detergents as washing agents on soiled white and dyed cotton fabrics

A K Samanta ,  Sunanda Mitra , Deepali Singhee & Smita Parekh

[IPC Code: Int. Cl7. D06L 1/ 02]

223

Techno-economic control systems for polyester manufacturing

A A Itagi, Mandar Shete, Kapil Asher & Nitin Kanade

[IPC Code: Int. Cl7. G06F 9/00]

233

 

 

Review Article

 

Colour removal from textile effluents

M Joshi, R Bansal & R Purwar

[IPC Code: Int. Cl7. C08J 11/04; C02F 1/00; C02F 3/00]

 

239

Report

 

Technological innovations in textiles¾ A report on the brain storming session

M L Gulrajani

260

 

 

Indian Journal of Fibre & Textile Research

 Vol. 29, June 2004, pp. 117-121

 

A successful weaving trial with a size-free cotton warp

A P S Sawhney, J B Price & T A Calamari

 

A combed cotton rotor-spun yarn of high quality was produced using customary industrial equipment. The yarn was warped, ensuring a consistent individual yarn tension. The warp set was uninterruptedly washed and cleaned in boiling water containing a mild detergent and a wetting agent, dried on a dummy slasher (i.e. without using any conventional sizing agent) to set the yarn twist torque, and wound onto a loom beam. A 2/1 twill fabric of a slightly open construction was successfully woven on a modified fly-shuttle loom, operating under normal speed and mill-like conditions. Although the yarn hairiness increased visibly as the warp raced forward towards the cloth fell, absolutely no fiber clinging or yarn snagging occurred and, for the first time ever, about 50 m of fabric was woven without a single warp yarn failure, which is very encouraging. This preliminary weaving trial indicates that weaving a singles cotton yarn without the traditional warp sizing may now indeed be feasible at least for certain types of yarns, fabrics and weaving machinery. Planned size-free weaving trials involving different types of fibers, yarns and modern weaving machinery are expected to determine the prospect and commercial scope of size-free weaving.

 

Keywords: Cotton, Size-free weaving

IPC Code: Int. Cl.7 D03D 25/00; D02G 3/00

 

 

 

Indian Journal of Fibre & Textile Research

 Vol. 29, June 2004, pp. 122-128

 

Air and water permeability characteristics of nonwoven fabrics

 D Bhattacharjee, A Ray & V K Kothari

 

Experimental investigations on air and water permeability characteristics of spunlaid heat-bonded Typar fabrics show a very close linear correlation between both the permeability values. The ratio of water permeability to air permeability is a function of the pressure head at which these values are measured. The values of air and water permeabilities themselves are a polynomial function of the fabric porosity. Hence, the knowledge of fabric porosity and the active pressure head would be enough to predict the air permeability and water permeability values of spunlaid heat-bonded fabrics.

 

Keywords: Air permeability, Darcy’s coefficient, Fabric porosity, Pressure head, Typar fabric, Water permeability

IPC Code: Int. Cl.7 D04H 3/00; G01N 15/00

 

 

 

Indian Journal of Fibre & Textile Research

 Vol. 29, June 2004, pp. 129-137

 

Modification of polyester fabric via radiation grafting with methacrylic acid

Eglal H K El-Gendy

 

Polyester fabric has been modified by radiation graft copolymerizaion with methacrylic acid (MAA) to improve its hydrophilic, dyeing and thermal properties . It is observed that the efficiency of grafting significantly depends on swelling agent, solvent, monomer concentration and irradiation time. The initial stage of grafting follows first order kinetics at irradiation time t < 41.5 min and the second stage follows 1.7 order kinetics at 41.5-170 min. Overall reaction rate constants of 1.9´10-5 and 2.87´10-4 s-1 have been calculated for the samples grafted below and above 41.5 min respectively. The moisture content is found to increase linearly with the increase in graft yield up to 28% while the water uptake is linearly dependent on the logarithm of graft yield. Extremely high colour strength values are obtained when grafted PET samples are dyed in alkaline aqueous solutions at pH 11.5. A linear dependence is observed between the colour strength per graft yield and the logarithm of the pH of Rhodamine B Red and Astrazonrot Violet dye solutions. The dyeability of the fabric towards both the dyes increases suddenly as the graft yield increases to 2.5% followed by a transition up to 7% with a tendency to level off at degree of grafting higher than 10%. Thermal stability of irradiated, grafted and dyed samples has also been investigated by thermal gravimetric analysis to observe different degrees of fabric degradation as a result of irradiation, grafting and dyeing.

 

Keywords: Dyeing, Methacrylic acid, Moisture content, Polyester, Radiation grafting, Thermal analysis, Water uptake

IPC Code: Int. Cl.7 D06M 14/08

 

 

 

Indian Journal of Fibre & Textile Research

Vol. 29, June 2004, pp. 138-142

 

Woven fabric behaviour during pulling disc-shaped specimen through a central hole

I Saukaityte, V Daukantiene & M Gutauskas

 

The behaviour of suiting during pulling a disc-shaped specimen through a central hole of replaceable stand was investigated. The tests were performed using KTU-Griff Tester. Fabric behaviour was evaluated on the basis of the parameters of the typical pulling curve H-P (punch height – pulling force): maximum pulling force (Pmax), tangent of the slope angle (tga) of initial part of curve H-P, pulling work (A), and changes in fabric thickness (d) and maximum specimen deformation (Hmax). The analysis of the changes in the specimen geometric parameters has shown that the parameters a and d of epicycloid and the number of waves (wrinkles) N depend on the level of deformation H and on properties of the tested fabric. The used method of pulling a disc-shaped specimen through a central hole of stand can be applicable for the investigation of mechanical properties of different textile fabrics, such as anisotropy of textile hand and drape.

 

Keywords: Biaxial deformation, Drape, Suiting, Textile hand, Woven fabric

IPC Code: Int. Cl.7 D03D 15/00; G01N 33/36

 

 

 

Indian Journal of Fibre & Textile Research

 Vol. 29, June 2004, pp. 143-148

  

Using drape form to establish discriminant models of fabric characteristics

Lai Sang-Song

 

This paper focuses on the approaches to discriminate between the fabrics with different characterized generic drape forms. Four fabric groups, woven from cotton, linen, wool and silk, were used. Discriminant analysis was used to characterize and discriminate between the different fabric groups. The parameters for analysis were from drape forms based on the Cusick fabric drape instrument. It is observed that the 14 drape forms are able to classify the four groups of fabrics with a 98.3% classification accuracy rate. Also, by using the factor analysis, the distribution of characteristics dimension for the four kinds of fabrics can be understood.

 

Keywords: Cotton, Drape form, Discriminant analysis, Linen, Silk, Wool

IPC Code: Int. Cl.D06J 1/00; G01N 33/36

 

 

 

Indian Journal of Fibre & Textile Research

 Vol. 29, June 2004, pp. 149-156

 

Prediction of air-jet textured yarn properties using statistical

method and neural network

V K Yadav & V K Kothari

 

Artificial neural network has been used for predicting the air-jet textured yarn properties and the performance of ANN model has been compared with the statistical model based on Box-Behnken response surface design. Leaving apart some stray cases, the artificial neural network is able to predict the properties with reasonably low prediction error. Prediction ability of the network is better for the instability and physical bulk property as compared to tenacity. For the set of data used for constructing the network, the mean square errors are comparatively higher in the neural network model than the regression model.

 

Keywords: Air-jet texturing, Artificial neural network, Box-Behnken design, Physical bulk, Polyester yarn, Response surface design

IPC Code: Int. Cl.7 G06N 3/02; D02 G 3/00

 

 

 

Indian Journal of Fibre & Textile Research

 Vol. 29, June 2004, pp. 157-162

 

Prediction of single yarn tenacity of ring-and rotor-spun yarns

from HVI results using artificial neural networks

 Abhijit Majumdar, Prabal Kumar Majumdar & Bijan Sarkar

 

Artificial neural network (ANN) models for predicting the single yarn tenacity of ring- and rotor- spun yarns form the cotton fibre properties, measured by high volume instrument, have been presented. Seven cotton fibre properties and yarn fineness have been used as the inputs to the neural network. Different network structures have been used to optimize the prediction performance. The relative importance of all the cotton fibre properties has also been quantified. The ANN models could predict the single yarn tenacity with less than 5% and 2% mean error in case of ring- and rotor- spun yarns respectively. Yarn fineness, fibre bundle tenacity, elongation and length uniformity are the dominant input parameters which influence the single yarn tenacity of spun yarns.

 

Keywords: Artificial neural network, Bundle tenacity, Cotton fibre, Ring yarn, Rotor yarn, Yarn tenacity

IPC Code: Int. Cl.7 G06N 3/02; D02G 3/00

 

 

 

Indian Journal of Fibre & Textile Research

 Vol. 29, June 2004, pp. 163-172

 

Tensile behaviour of polyester yarns modified by solvent-acid

mixture pretreatment process

D Chidambaram ,  R Venkatraj & P Manisankar

 

The tensile behaviour of original and heat-set fine filament and microdenier polyester yarns treated with trichloroacetic acid-chloroform (TCAC) solvent system has been studied. The polyester yarn samples have been treated in a relaxed state with various concentrations of TCAC mixture at room temperature for different durations. It is observed that the TCAC treatment causes significant changes in strength and elongation behaviour of original fine filament and microdenier polyester yarns. The solvent-treated yarns exhibit higher breaking elongation, improved work of rupture and lower tenacity. The improvement in elongation and work of rupture is found to be less in the case of heat-set polyester yarns due to the subsequent TCAC treatment. The influence of treatment time and heat setting temperature on strength, elongation, yield behaviour and work of rupture of TCAC-treated yarns has also been investigated.

 

Keywords: Fine filament yarn, Heat setting, Microdenier yarn, Polyester, Tensile behaviour

IPC Code: Int. Cl.7 D02G 3/00; D02J 1/00

 

 

 

Indian Journal of Fibre & Textile Research

Vol. 29, June 2004, pp. 173-178

 

Study on drafting force of roving: Part I – Effect of process variables

A Das, S M Ishtiaque & Rajesh Kumar

 

The effect of process variables, namely draft, drafting speed and roller setting, on drafting force of polyester/viscose (65:35) roving has been studied. A reasonably good correlation (R2 = 0.855) between process variables and drafting force has been observed. The drafting force at first increases with the increase in draft but after reaching a maximum value, it declines sharply. The drafting force increases with the increase in drafting speed and the same trend is also observed at lower draft and roller setting. But when the draft and roller setting further increase, initially the drafting force remains unchanged with the increase in drafting speed and then it declines. The roller setting has been found to be inversely proportional to the drafting force for all the experimental combinations.

 

Keywords: Drafting force, Drafting speed, Roller setting, Polyester fibre, Viscose fibre

IPC Code: Int. Cl.7 D02G 3/00; D01H 5/00

 

 

 

Indian Journal of Fibre & Textile Research

 Vol. 29, June 2004, pp. 179-183

 

Study on drafting force of roving: Part II - Effect of material variables

A Das, S M Ishtiaque & Rajesh Kumar

 

The effect of some material variables, namely fibre-to-fibre friction, roving hank and roving twist, on drafting force of roving has been studied. A very good correlation (R2 = 0.903) between material variables and drafting force has been obtained. The drafting force increases sharply with the increase in fibre friction and roving twist multiplier due to the rapid increase in mutual coherence among the fibres. The drafting force is less influenced by the change in roving hank, but it decreases initially and then increases as the roving hank becomes finer.

 

Keywords: Cotton, Drafting force, Fibre friction, Roving hank, Twist multiplier

IPC Code: Int. Cl.7 D02G 3/00; D01H 5/00

 

 

 

Indian Journal of Fibre & Textile Research

Vol. 29, June 2004, pp. 184-189

 

Variation in polyester-viscose and polyester-cotton ring-and rotor-yarn characteristics as a consequence of fibre cross-section

G K Tyagi, K R Sharma, A Goyal & Mandeep Singh

 

The influence of twist factor and rotor speed on the properties of polyester ring and rotor yarns spun from polyester fibres of circular and trilobal cross-sections has been studied. The results show that the fibre profile plays a key role in determining the mechanical and surface properties of all-polyester, polyester-viscose and polyester-cotton yarns, as evidenced by the fact that both ring and rotor yarns spun with trilobal polyester fibres have lower tenacity, higher breaking extension, more twist liveliness, lower work of rupture and higher flexural rigidity. Furthermore, lesser yarn-to-metal friction, higher dye pick-up and low hairiness can be obtained for blended yarns having polyester fibres of non-circular cross-section. Both twist factor and rotor speed strongly affect all yarn properties and the behaviour is similar for all the yarns.

 

Keywords: Circular fibre, Flexural rigidity, Polyester yarn, Rotor-spun yarn, Trilobal fibre, Wrapper fibre

IPC Code: Int. Cl.7 D02G 3/00

 

 

 

Indian Journal of Fibre & Textile Research

 Vol. 29, June 2004, pp. 190-195

  

Optimization of ring frame process parameters for better yarn quality and production

S M Ishtiaque, R S Rengasamy & A Ghosh

 

Ring frame process parameters, namely spindle speed, top roller pressure and traveller mass, have been optimized using three-variable Box and Behnken design to achieve better yarn quality and production. It is observed that 15000 rpm spindle speed with top roller pressure of 2.5 kg/cm2 and traveller mass of 50 ISO No. gives the optimum results within the experimental zone explored. But to achieve the spindle speed of 17000 rpm, the traveller mass of 40 ISO No. with the optimum value of top roller pressure gives acceptable running performance of the machine.

 

Keywords: Spindle speed, Top roller pressure, Traveller mass

IPC Code: Int. Cl.7 D01H1/02; D02G 3/00

 

 

 

Indian Journal of Fibre & Textile Research

 Vol. 29, June 2004, pp. 196-199

 

Effect of process parameters at comber on yarn and fabric properties

S Subramanian & N Gobi

 

The effect of different process parameters at comber on yarn and fabric properties for the same noil% has been studied. It is observed that there exists a best combination of process parameters at comber for every noil % based on the length and length distribution of fibre. While selecting these process parameters, it is necessary to study the classimat faults as well as fabric appearance instead of only yarn imperfections and tenacity. The increase in top comb penetration beyond a certain level increases the classimat faults in the categories H and I due to the disturbance of combed fringe by the top comb, though there is a reduction in the imperfections and classimat faults due to raw material.

 

Keywords: Classimat faults, Cotton, Combing efficiency, Comber noil

IPC Code: Int. Cl.7 D01H 13/00; D02G 3/00; G01N 33/36

 

 

 

Indian Journal of Fibre & Textile Research

 Vol. 29, June 2004, pp. 200-206

 

Fine structure variations of polyester tow at different treatment conditions

J Maillo, D Cayuela, J Gacén, E Estrenjer & A M Sitges

 

Differences in fine structure of a polyester tow stabilized at different conditions of temperature, treatment time and compactness have been studied. The effective temperature of thermal treatments, crystallinity, and total and superficial oligomers have been determined. The variation in fine structure due to stabilization treatment through iodine sorption and differential solubility tests has also been studied. It is observed that the temperature is the most important variable in the process as it produces important fine structure variations (crystallinity differences). The compactness is the less important variable of the process.

 

Keywords: Differential scanning calorimetry, Differential solubility, Iodine sorption, Polyester

IPC Code: Int. Cl.7 D01G 37/00

 

 

 

Indian Journal of Fibre & Textile Research

 Vol. 29, June 2004, pp. 207-217

 

Influence of cooking and adjustment treatments on reeling and quality characteristics of raw silk

G Hariraj &T H Somashekar

 

The hot air dried Indian multi-bivoltine cocoons (PM × NB4D2 race) treated at different cooking temperatures, cooking durations and adjustment temperature profiles in pan system of cooking have been found to have significant influence on reeling characteristics, viz. groping end efficiency, reelability, raw silk percentage, raw silk recovery percentage, reeling tension, waste generated during reeling, pelade weight generated and degumming loss percentage of silk waste, and on quality characteristics, viz. neatness, cleanness, cohesion and degumming loss percentage of raw silk. However, the complete cooking and reeling do not show significant influence on sericin dissolution during cooking and reeling, tenacity and elongation. The study clearly shows that the complete cooking of cocoons in pan system of cooking using five treatment temperatures effectively softens the sericin uniformly in different layers of the cocoon shell compared to single temperature treatment, thus facilitating the improved reeling performance from hot air dried Indian multi-bivoltine cocoons. The cocoon cooked using the retting temperature of 50°C for 1 min, high permeation temperature of 90°C for 2 min, low permeation temperature of 60°C for 1 min followed by the cooking temperature of 93-95°C for 2 min and adjustment temperature of up to 60°C yields better reeling performance and quality of raw silk.

 

Keywords: Degumming, Multi-bivoltine cocoon, Silk

IPC Code: Int. Cl.7  D01B 7/00

 

 

 

Indian Journal of Fibre & Textile Research

  Vol. 29, June 2004, pp. 218-222

 

Utilization of chitosan citrate as crease-resistant and antimicrobial finishing agent for cotton fabric

Aly Sayed Aly , Ali Hashem & Samaha Sayed Hussein

 

Chitosan citrate has been evaluated as non-formaldehyde durable press finish to produce wrinkle-resistance and antimicrobial properties for cotton fabrics. The carboxylic groups in the chitosan citrate structure were used as active sites for its fixation onto cotton fabrics. The fixation of the chitosan citrate on the cotton fabric was done by the padding of chitosan citrate solution onto cotton fabrics followed by dry – cure process. The factors affecting the fixation processes were systematically studied. The antimicrobial activity and the performance properties of the treated fabrics, including tensile strength, wrinkle recovery, wash fastness and whiteness index, were evaluated. The finished fabric shows adequate wrinkle resistance, sufficient whiteness, high tensile strength and more reduction rate of bacteria as compared to untreated cotton fabric.

 

Keywords: Antibacterial finishing agent, Chitosan, Chitosan citrate, Cotton, Crease resistance

IPC Code: Int. Cl.7 D06C 29/00; D06B 3/00

 

 

 

Indian Journal of Fibre & Textile Research

 Vol. 29, June 2004, pp. 223-232

 

Efficacy of selective surfactants/detergents as washing agents on soiled white and dyed cotton fabrics

A K Samanta,  Sunanda Mitra, Deepali Singhee & Smita Parekh

 

Four different types of surfactant, namely alkyl benzene sulphonate (A), sodium lauryl sulphate (B), glycerol monostearate (C) and distearyl dimethyl ammonium chloride (D), have been used in single and multiple washing of a soiled white/dyed cotton fabric to determine their critical micelle concentration (CMC) values and to assess their washing performance in terms of changes in some of the physical properties of fabrics, per cent soil removal from soiled white fabric and maximum retention of colour depth of dyed fabric. The washing performance of each surfactant at lower concentration level by multiple wash cycles has also been studied. Wash fastness rating by grey scale and washing performance in terms of retention of colour depth of reactive dye dyed cotton fabric have been assessed and compared by measuring the corresponding K/S values and colour difference values after washing with these surfactants by ISO-II and ISO-III methods. It is observed that the CMC value and the corresponding degree of soil removal at CMC level are 1.9 % and 90.8 % for surfactant A, 1.5 % and 90.6 % for surfactant B, 2 % and 92 % for surfactant C, and 1% and 39.4 % for surfactant D respectively. On multiple wash, the surfactants C and D do not show good performance at lower concentration (0.5-1%), while the surfactant B is found to be better than others. Considering the changes in physical properties of fabrics after washing, washing performance, critical micelle concentration of surfactants and retention of colour depth after washing, the surfactant B shows an overall balanced performance.

 

Keywords: Colour strength, Cotton, Critical micelle concentration, Detergent, Surfactant, Wash fastness

IPC Code: Int.Cl.7 D06L 1/ 02

 

 

 

Indian Journal of Fibre & Textile Research

 Vol. 29, June 2004, pp. 233-238

 

Techno-economic control systems for polyester manufacturing

A A Itagi, Mandar Shete, Kapil Asher & Nitin Kanade

 

A new approach for process control in polyester manufacturing plants is presented, which is based on the distributed control system and simulation, enabling a high degree of automation. The technology seems to be stable process with operational ease providing protection against misguidance and wastage. Although a high initial investment is called for nonetheless high investments can be recovered in just three years of installing this technologically superior and economically viable control system.

 

Keywords: Distributed control system, Polyester, Programmable logic controller

IPC Code: Int. Cl.7 G06F 9/00

 

 

 

Indian Journal of Fibre & Textile Research

 Vol. 29, June 2004, pp. 239-259

  

Colour removal from textile effluents

M Joshi, R Bansal & R Purwar

 

The environmental issues associated with residual colour in textile effluents have posed a major challenge to environmental scientists as well as the textile colouration processors. The requirements to remove colour from textile effluent on site prior to discharge to sewer have been progressively tightened due to increased public complaints about coloured watercourses. Dyes are highly dispersible aesthetic pollutants and are difficult to treat, as most dyes are highly stable molecules made to resist degradation by light, chemical, biological and other treatment or exposure. There has been a lot of research going in the past few decades to develop efficient and cost effective technologies to remove colour from textile effluent. This paper presents a critical review of the current literature available on various textile wastewater decolourisation techniques being applied and researched to remove colour from textile wastewater.

 

Keywords: Colour removal, Dye separation, Textile effluent

IPC Code: Int. Cl.7 C08J 11/04; C02F 1/00; C02F 3/00