Membrane reactor turns methane into aromatics
A new reactor can directly convert natural gas into valuable liquid feedstock petrochemicals, such as benzene, in a single step.
The work could pave the way for cheap, clean and simple conversion of methane into aromatic precursors for a wide range of products including plastics and fuels that are normally derived from oil.
Natural gas is mostly methane and is usually converted into precursor chemicals by converting it into syngas – a mixture of hydrogen and carbon monoxide.
However, the end products tend to be transport fuels not aromatics and it’s expensive which restricts production to large gas fields, meaning many smaller fields remain untapped.
Non-oxidative methane dehydromatisation (MDA) using a zeolite catalyst is touted as a promising route for direct and cheaper methane conversion.
However, the process has struggled because of thermodynamic limitations and a build-up of coke deposits which poison the catalyst.
Now, a Norwegian and Spanish team has designed an MDA process that uses a ceramic co-ionic barium zirconate membrane in the catalytic reactor to simultaneously remove hydrogen and injects oxygen.
It works because hydrogen is a reaction product and so reducing its concentration shifts the thermodynamic equilibrium, which enables the system to produce more reaction products, namely benzene.
However, hydrogen removal promotes coke formation and catalyst degradation. This was overcome by the injected oxygen which reacts with coke to minimise catalyst degradation.
‘The fact of achieving higher yields but also much higher stability was fully unexpected,’ says co-author Jose Serra at the Institute of Chemical Technology in Valencia, Spain.
He says the exploitation of the co-ionic character of the membrane was the key. ‘Ceramic proton conductors, such us barium zirconate, are very stable at high temperature in contrast to metallic membranes and do not promote coking reactions when exposed to hydrocarbons at high temperature,’ he explains.
Serra envisages exploitation of smaller sources of methane such as biogas from organic waste and residual methane at production or processing sites, which is currently flared off.
‘Another option is in situ, on demand production of aromatics to meet the demand of chemical industries, plastics producers, additive manufactures, and so on,’ he adds. ‘Chemical companies could produce benzene by themselves just by using methane “from the tap”.’
CoorsTek, the Norwegian company behind the ceramic membrane technology and project collaborator, has already scaled up production of the membranes and is now building a pilot plant.
But the commercial feasibility of this process is yet to be determined, remarks James Spivey, who investigates natural gas catalysis and conversion at Louisiana State University, US. ‘There is much to be done in terms of the stability of the BZCY72 membrane and how best to reduce the small, but not negligible, carbon monoxide yield,’ he explains. ‘Despite these limits, this is a significant and clear advance over current technology.’
S H Morejudo et al, Science, 2016, DOI: 10.1126/science.aag0274
Novozymes’ new technology offers cold bleaching to denim manufactures
- November 2014
Diverse denim looks can be achieved with the latest enzymatic innovation. Working with cold water and reducing the use of the chemicals, the solution quickens the denim bleaching process, and secures higher quality denim.
Almost 20 years ago, denim bleaching became safer and more sustainable with the launch of Novozymes DeniLite®. Using enzymatic technology instead of harsh chemicals, the solution offered a gentle alternative for denim processing. Novozymes’ latest offering is a cold bleaching product known as DeniLite® Cold.
Cold, gentle and rapid processing
“Our cold bleaching solution is effective at tap water temperature,” says Ole Bill Jørgensen, business development manager for Novozymes’ Textile division. “Other bleaching technologies require the use of more energy or water, and in some cases more process steps, to achieve the same bleaching effect.”
The enzymatic bleaching solutions that are currently available are usually based on enzymes known as laccases. They alter the indigo through oxidation. Depending on oxygen from the water or from the air, this form of denim bleaching can take a long time, and the processing step can require repetition. The new cold bleaching solution is based on enzymes known as peroxidases, and this innovation is formulated to work without extra oxygen from either the air or water. This new peroxidase has a very rapid reaction speed – 90% of the reaction finishes within 10 minutes.
The cold bleaching technology also secures improved fabric durability due to the gentle bleaching conditions. Enzymatic solutions are extremely specific, working only on the indigo dye on the fabric. Unlike harsher bleaching chemicals, this means that strength and elasticity of the fabric remains unchanged.
Fabrics are often colored using both indigo and sulphur dyes. The cold bleaching solution is very effective when used with indigo dyes. It does not bleach black or brown sulfur dyes, and only slightly alters the tone of blue sulfur dye. This means that different color tones can be achieved with the same fabric using different dye combinations. The shades of cold finished fabrics can be very different from those finished with traditional chemicals.
“Novozymes’ cold bleaching solution can achieve in-demand fashion looks,” says Ole Bill Jørgensen. “Denim processors can apply this technology to current trends and create diverse looks for brand owners very quickly. Even just one wash cycle using this technology can create a variety of different color tones. We believe the full fashion potential will be further explored when the technology becomes broadly available to the industry.”
Teijin Ltd : Teijin Develops New Phosphorus Flame Retardant [Teijin]
September 30 ,2013
Tokyo, Japan, September 27, 2013 — Teijin Limited announced today that it has developed new phosphorus flame retardant, FireguardFCX-210, usable for a wide range of resins. With its now enhanced line-up of brominated flame retardants, the company plans to develop applications with particular focus on the electronics and automotive markets. Teijin expects revenue from its flame retardant business to reach 4 billion yen by fiscal 2018.
FireguardFCX-210 is a new type of phosphorus flame retardant, developed using Teijin’s proprietary molecular design technology, which lends high flame retardancy to a broad range of plastics widely used in office equipment, electronic appliances, game consoles, and automobiles. These include styrene resins such as ABS and polystyrene and polyamide resins such as nylon, with which conventional phosphorus flame retardants are less effective.
Adding conventional phosphorus flame retardants to resins generally reduces their effectiveness. But FireguardFCX-210 loses none of its flame resistance and can be added without changing the original characteristics of the resin. Additionally, only a relatively small amount is necessary. With high impact polystyrene, for example, the necessary amount of flame retardant is reduced by approximately 40%.
FireguardFCX-210 is also a halogen-free product, making it safer for end-users and more environmentally friendly.
Along with rapid performance improvements in office equipment, electronic appliances, and automobiles, consumers have come to expect safer and more environmentally friendly products as well. Flame retardants — additives that make flammable materials, such as plastics, difficult to burn — are widely used to achieve this.
Phosphorus flame retardants are a key type of retardant and highly effective especially when added to polycarbonate and polyester resins.FireguardFCX-210 answers to strong customer demand for the development of flame retardant that can also be applied to other types of resin, and does not reduce the heat resistance of materials on which it is used.
The Teijin Group is also developing applications and processing methods forFireguardFCX-210 using other Teijin materials.
About the Teijin Group
Teijin (TSE 3401) is a technology-driven global group offering advanced solutions in the areas of sustainable transportation, information and electronics, safety and protection, environment and energy, and healthcare. Its main fields of operation are high-performance fibers such as aramid, carbon fibers & composites, healthcare, films, resin & plastic processing, polyester fibers, products converting and IT. The group has some 150 companies and around 17,000 employees spread out over 20 countries worldwide. It posted consolidated sales of JPY745.7 billion (USD 7.4 billion) and total assets of JPY 762.4 billion (USD7.6 billion) in the fiscal year ending March 31, 2013.
+81 3 3506 4055
Aquafil Group recycling used fishing and fish farm nets
Posted by admin
A Sustainability Concept: Recycling of End-of-Life Netting Materials
An advanced recycling technology is helping to recycle polyamide 6 spent nets into
carpeting and apparels.
The Aquafil Group specializes primarily in the production, marketing and supply of nylon 6
synthetic yarns and polymers. The company has developed a strong focus in applying
sustainability principles in two ways. The first is in the development of new sustainable
products from recycle raw material sources with co-marketing activities with clients and
suppliers. The second is the use of low environmental impact or renewable energies
The Group employs more than 1,900 people and has a presence in three continents:
Europe, North America and Asia. In Europe, it has five production facilities in Italy, three
in Slovenia and one in Croatia. The North American facility is in Cartersville, Georgia,
USA. In Asia, there is a facility in Thailand and a new 2011 production facility opened in
China, located in Jiaxing City, near Shanghai.
The Aquafil mission is to generate a closed loop cycle of sustainable polyamide 6
products. In doing this, the group has also discovered a wide range of end-of-life goods
that can be used for this purpose, such as fish-nets (fish farm cage nets, gill nets and
some trawling and purse seine nets). This is possible due to an advanced recycling
technology. The recovery of polyamide 6 spent nets also avoids environmental concerns
to water bodies, oceans and beaches, from stray or abandoned ghost netting materials.
The group is operating a new post-consumer recycling plant in Slovenia.
Recycled polyamide (also known as Nylon)
The recycled polyamide content is called Econyl®. With this project, Aquafil attains full
sustainability in its production process while at the same time overcoming the problems
associated with regulations on waste disposal. At the end of their useful life, these spent
products are most typically land filled or stored in perpetuity. Both of which are a
negative impact to the environment and a possible impediment to industry growth. In
some cases the nets are incinerated, in the best cases for fuel or energy recovery. More
importantly, closed loop recycling these materials, at the end of their useful life, directly
displaces and reduces the consumption of natural resources, both in the form of raw
materials derived from crude oil, and as electricity, thermal energy and utilities in general
obtained from fossil fuels.
This Econyl® project is Aquafil’s path towards full sustainability in its production process.
The company says that, “this is one of the most complete ecological recycling systems. It
starts with polyamide 6 post consumer waste scraps and ends up with yarns that are
made into carpeting/apparel, returning it to virgin grade quality and the full brilliant color
possibilities Aquafil is well known for, all in a continuous cycle.
However, all these processes will be more promising with the cooperation of clients,
associations and groups that will help to recover the end of life goods needed in closing
the ‘reclaim-recycle and reuse’ loop.”
Aquafil is promoting an “Econyl® for sustainable design” product development methodology
so that their customers can better champion end of product life responsibility and
stewardship. For aquaculture this means designing products with theend of life in mind by
using polyamide 6 based netting and ropes while minimizing other polymers in net
construction going forward. Remember end of net life management begins when you
source your materials of construction or make the purchasing decision.”
The fishing and aquaculture industry can support this sustainability initiative by supplying
end-of-life netting materials. Aquafil is seeking the assistance of industry members,
stakeholders, associations and government organizations to identify possible sources. It will
also make compensation and transport arrangements. Those interested, please contact:
For Canada, North and South America
1 Aquafil Drive
Cartersville, GA 30120 U.S.A.
Europe and Asia
Via Linfano 9
38062 Arco (TN) – Italia
office: +39 0464 581105
cell: +39 348 3115102
E-mail : Ladislao.Labriola@aquafil.com
More information: web:
Researchers develop rapid method to measure carbon footprints
October 30, 2012
Researchers have developed new software that can rapidly calculate the carbon footprints of thousands of products simultaneously, a process that up to now has been time consuming and expensive.
A new methodology allows companies to determine carbon footprints…
The methodology should help companies to accurately label products, and to design ways to reduce their environmental impacts, said Christoph Meinrenken, the project’s leader and associate research scientist at Columbia University’s Earth Institute and Columbia Engineering. A new study, published online in the Journal of Industrial Ecology, describes the methodology.
The project is the result of a collaboration between the institute’s Lenfest Center for Sustainable Energy and PepsiCo, Inc. Its original aim was to evaluate and help standardize PepsiCo’s calculations ofthe amount of carbon dioxide emitted when a product is made, packaged, distributed and disposed of. Started in 2007, it resulted in the first U.S. carbon footprint label certified by an impartial third party, for Tropicana orange juice. PepsiCo has been pilot-testing the methodology for other uses since 2011.
Meinrenken and his team used a life-cycle-analysis database–a tool used to assess the environmental impact of a product–that covered 1,137 PepsiCo products. They then developed three new techniques that work together, enabling them to calculate thousands of footprints within minutes, with minimal user input. The key component was a model that generates estimated emission factors for materials, eliminating manual mapping of a product’s ingredients and packaging materials. Meinrenken said the automatically generated factors enable non-experts “to calculate approximate carbon footprints and alleviate resource constraints for companies embarking on large-scale product carbon footprinting.” He said the software complies with guidelines sponsored by the nonprofit World Resources Institute, which provides standards against which carbon footprints can be audited.
Up until now, life-cycle-analysis has mostly been performed one product at a time. This imposes large requirements for personnel, expertise, and time, and few companies have enough employees with specialized expertise. Meinrenken said that some have tried to overcome this bottleneck by reverting to aggregate data and calculations, but they usually miss out on the microscopic level of detail that a proper analysis requires.
The researchers’ approach was inspired by fields outside environmental science, Meinrenken said. “At companies like Facebook or Netflix, engineers employ statistical wizardry to mine vast datasets and essentially teach computers to predict, for instance, who will like a particular movie,” he said. He used similar methods to mine detailed product and supply chain data. “For an environmental engineer, using such data to estimate how much the environment will ‘like’ certain products and services is especially rewarding,” he said. “Consumers will be able to make more informed choices.” The information can also help companies design and assess ways to lessen products’ impacts, he said.
Al Halvorsen, senior director of sustainability at PepsiCo, said, “The newly developed software promises to not only save time and money for companies like PepsiCo, but also to provide fresh insights into how companies measure, manage, and reduce their carbon footprint in the future.”
Klaus Lackner, director of the Lenfest Center for Sustainable Energy, said, “Fast carbon footprinting is a great example of how academic methodologies [coupled] with modern data processing and statistical tools can be brought to life and unlock their power in the real world.” Meinrenken’s team is now looking at transferring the methodology from carbon to other arenas, such as water use.
Source: The Earth Institute at Columbia University –
UMass, Delaware researchers develop low-cost process to make plastic from plants
May 17, 2012
By Stan Freeman
Monica M. Davey/Feature Photo Service for IBMAMHERST
A team led by a University of Massachusetts chemical engineer has developed a low-cost, high-yield process for making one of the most common plastics using plant matter rather than petroleum.
The new process produces polyethylene terephthalate, or PET, which is used widely in soda and water bottles, as well as in synthetic fabrics such as polyester.
“You can mix our renewable chemical with the petroleum-based material and the consumer would not be able to tell the difference,” said Paul J. Dauenhauer, an assistant professor of chemical engineering, who led the team of researchers from UMass and University of Delaware.
Their findings were recently published in the journal ACS Catalysis.
Consumers know PET plastics by the triangular recycling label “#1” on plastic containers. PET plastics are made with a chemical, p-xylene, which is traditionally derived from petroleum. The new process transforms glucose, a simple sugar derived from such things as grasses and trees, into p-xylene.
Although other processes exist to produce p-xylene from biomass, none are as inexpensive or as efficient as the new process, said Dauenhauer.
“A complete cost analysis and process design is still one to two years away, because we have just made the scientific discovery,” he said. “However, our process does have significant benefits over competing technologies. For example, our process can achieve 75 percent yield of p-xylene, while competing technologies only achieve yields below 20 percent. This means that we can potentially make over three times the quantity of biomass-derived plastics from a ton of biomass relative to our competitors.”
“Our discovery shows remarkable potential for green plastics,” said Dionisios G. Vlachos, a chemical engineering professor at University of Delaware who was part of the team. “This technology could significantly reduce production costs for manufacturers of plastics from renewable sources.”
Dauenhauer said the team’s plan is to license the process to companies, and that UMass would share in any royalties.
In addition to Dauenhauer and Vlachos, the research team included UMass professor Wei Fan, and UMass doctoral students in chemical engineering, C. Luke Williams and Chun-Chih Chang. Also part of the team were University of Delaware professors Raul F. Lobo and Stavros Caratzoulas, as well as doctoral student Nima Nikbin, and postdoctoral fellow Phuong Do.
Much of the funding for their research came from the U.S. Department of Energy.
Modification of polyester (PET)
The modification of PET fibres for improved dyeability, differential dyeing, antibacterial properties, reduced flammability, high water absorbency and mechanical properties are vital to overcome drawbacks, emphasises Aravin Prince P. Polyesters are polymers made by a condensation reactions taking place between small molecules, in which the linkage of the molecules occurs through the formation of ester groups. Polyesters are commonly made by interaction of a dibasic acid with a dihydric alcohol. This fibre is a medium weight fibre with a density of 1.39 g/cm3 . Compared with nylon, polyesters are rather heavy fibres; For this reason polyester textile materials are manufactured as lightweight or thin fabrics. The most common polyester apparel filament or stable fibre is usually composed of polyethylene terepthalate (PET) polymers.
Why modified polyesters are prepared?
The modified polyesters are prepared to overcome some drawbacks such as low moisture regain, static electricity and soiling problems, this three drawbacks are interrelated and associated with hydrophobicity of the polyester. By making hydrophilic these drawbacks can be overcome. Thus, a hydrophilic fibre will have a higher moisture regain. The garments made up of hydrophilic fibre will absorb perspiration and will be comfortable.
Other drawbacks are pilling problem and extreme difficulty in dyeing. The low pilling fibres are required to retain the elegant appearance of polyester garments for a long time. These low pilling fibres have lower tenacity than normal polyester fibres. Thus, although pills are formed in these fabrics, these pills are removed by simple brushing or washing.
Modification of polyester fibres
Polyester fibres were latecomers among manufactured fibres, and had to find their way into a market where polyamide and acrylic fibres were already established. Polyester fibres used for textile application offer tangible benefits to both processors and consumers. Low denier fibres blended with cotton gave higher strengths at lower twist levels, than found in 100% cotton yarns. The characteristic property of the polyester was immediately encashed by the designers of shirt and blouse fabrics. Polyester fibres provided textiles with a dimensional stability, wear resistance and easy care properties with the handle, drape and appearance being preserved for longer periods than in fabrics made from natural fibres.
High rate of growth of polyester fibres is due to their outstanding physical properties, chemical resistance, easy properties, and resistance to moth, mildew and microorganism. In spite of its outstanding performance, there are some shortcomings in PET, for example:
# Hydrophobic nature.
# Ease of soiling.
# Static charge build-up.
# Tendency to pill.
# Lack of dye receptor sites in the polymer chain.
Extensive research has therefore, been carried out on PET to overcome the above mentioned drawbacks. Such changes (physical and chemical) have led the manufacture of modified polyester fibres. Modification of normal polyester has been accomplished by following routes:
* Change in the chemical composition of the PET molecule by introducing a third and/or fourth component into the polymer chain during polymerisation.
* Use of certain additives (particulate fillers, pigments of polymers) in the melt phase prior to extrusion.
* Modification during melt spinning such as hollow varied profile and micro-denier fibres for specific applications.
* Surface modification of normal polyester fibre for producing specific effects.
Modifications for improved dyeability
During dyeing, the dyestuffs diffuse into the fibre and are absorbed primarily by the amorphous regions. The thermal coefficient of the molecular mobility, responsible for the dye diffusion, depends largely on the Tg, which increases with increase in crystallinity and the degree of orientation of the fibre. It has been demonstrated that drawing and heat setting cause a significant reduction in the rate of dye absorption, which, however, can be improved by introducing certain hydrophilic co-monomers in the PET molecule.
Deep dyeable PET (DD-PET):
Modification of the polymer to reduce the glass transition temperature (Tg) is helpful in increasing the dyeing rate. The most effective co monomers are aliphatic in character. Replacing a small proportion, usually 5 – 10 mo1%, of terephthaloyl units with an aliphatic dicarboxylic acid such as glutaric or adipic acid produces fibres that will dye at the boil without carriers; Aromatic units, derived for instance, from isophthalic acid, act primarily through reducing crystallinity, are less effective. Since to a first approximation, the depression of melting temperature on copolymerisation is proportional to the molar percentage of the modifier, a flexible comonomeric unit of high molecular weight is particularly useful.
Poly (ester-ether) fibres:
Block copolymers made from PET and polyalkylene glycols, ie, polyethylene or polypropylene glycols having Mn 1000 – 3000 molecular showed good dyeability with disperse dyes. Deep shades can be obtained in a boiling bath without carriers.
Block co-polyesters containing PET and polyethylene oxide [PEO] segments syntherised in the presence of lead oxide and Mn, Sb, Sn or Mg based catalysts have been reported. Poly (ester-b-ether) by incorporating ether blocks (PEG-1000) in the PET backbone.
Polyester co-polymer fibres made from a mixture of ethylene glycol, diethylene glycol and dimethylterephthalate showed improved dyeability and are found useful as binder fibres in fibrefill battings for sleeping bags and sky jackets.
However, the fibres made from these copolymers have the drawback of being very sensitive to thermal, hydrolytic and photochemical degradation reaction.
Features of deep dyeing PET are:
* Better dyeability (for disperse dyestuffs).
* Shorter dyeing time.
* Spinning throughput increased by as much as 5%.
* Higher water take-up (0.8% against 0.4% in unmodified PET).
* Agreeable hand and soft feel of fabrics.
Carrier free dyeable polyester (CFDP):
Carrier free dyeable polyesters are defined as those polyesters, whose dyeability at boil without the use of carriers is similar to that of polyester fibres dyed under HTHP conditions, or at boil in the presence of carriers. There are two approaches for producing CFDP.
v Physical modification of fibres
The dyeing properties of polyester are strongly influenced by many of the processing conditions to which the may be subjected during manufacturing or during subsequent textile processing. Efforts have been made to improve the dyeability of polyester, to produce CFDP by making certain change in melt spinning, drawing and heat setting operations. Air texturing and filament mixing have also been used to produce a whole variety of products. But the most importance technique at hand is the draw texturing of partially oriented yarn (POY).
Chemical modification of polymer
Chemically modified CFDP is produced by adding certain additives – polyethylene glycol (PEG), adipic acid azillic acid-which form block copolymers with polyester. Several properties are claimed for the fibre, including good dyeability at 100o C, physical properties and tensile strength are comparable with the normal polyester. The glass transition temperature of all these fibres is about 10o C, lower than of normal polyester, leading to higher segmental mobility. This in turn increases the rate of dye diffusion into fibres at a lower temperature and can be dyed deep shades at boil even in the absence of carriers.
These fibres offer the following advantages over normal polyester:
* Better exhaustion under atmospheric conditions.
* A higher colour yield.
* Shorter dyeing cycle.
* Reduction in dyeing costs.
* Elimination of the carrier cost.
* Energy saving.
* Environment protection, ie, ecological advantages.
* Possibilities of the dyeing of PES/wool of PES/acrylic blends.
* Reduction of the oligomer problem during dyeing.
(PET-b-PEG) based CFDP:
The simplest and most common method of manufacturing modified polyester is by incorporating a modifying agent, during Tran’s esterification, poly condensation or during melt blending. In considering the nature of the block to be introduced into the molecule, the following criterion could be adopted:
* The block should contain chemical groups of a hydrophilic nature to assist in the swelling of the fibre in aqueous solution.
* The fibre intermediate forming the block must have some reactive end groups like carboxyl or hydroxyl, capable of undergoing poly condensation.
* It must be thermally stable at 275 – 280o C in order to withstand polymer melt spinning conditions.
* It must be chemically stable under these conditions.
The above conditions limit the choice of modifying component, but of the few available, polyesters are the most interesting. Thus, the most popular modifiers today are a range of polyethylene glycols of the general formula H (OCH2CH2) nOH. Polyethylene glycols fulfill all the four conditions stated above and also exhibit very little scatter in the molecular weight.
Problems of CFDP:
Carrier-free dyeable polyester is associated with many problems. Some of them are listed below:
Levelness of dyeing: Due to the extremely high rate of exhaustion of dyes, there is a problem of localised absorption of dyes in the boundary zones between fibre surface and the dye liquor, which leads to uneven dyeing. This can be rectified by maintaining a uniform concentration gradient between fibre and the dyebath, at all points of the fibre, which can be achieved by rapid dye liquor circulation, or high fabric speed.
Light fastness of dyed fabrics: It is found that the dyes on carrier free dyeable polyester are more photosensitive that on the normal fibres. Kuster and Herlinger have studied this problem and suggested the use of stabilisers, which make their exhaustion from the dye bath possible. These compounds quench the primary radicals.
Wash fastness of dyeing: Wash fastness of the dyeing is also slightly low for these fibres because of the fibre structure, the dye molecules are not effectively trapped within the fibre structure. In other words, the factors that enhance diffusion into the fibre will also enhance diffusion out of it, when concentration gradients are reversed. Thus, appropriate instructions should be given to consumers to wash CFDP products at temperatures below 50o C.
Cationic Dyeable Polyester (CD-PET)
In normal dyeable polyester, there are no sites for ionic dyes. So, it can only be dyed by disperse dyes. Compared to ionic dyes, disperse dyes have smaller molecular extinction coefficients and lower build-up property. So these dyes cannot give bright and deep colours. Moreover, fastness to sublimation and wet treatments of disperse dyes are relatively poor compared to other classes of dyes. In order to avoid these problems, cationic dyeable polyester was developed.
Manufacturing of CD-PET:Co-polymerisation of an isophthalic acid component containing a sulfonic acid group makes it possible to use cationic dyestuffs for polyester staple fibres and filaments. Generally, the sodium salt of 5-sulfo-isophthalic acid (Na-SIPA) is used as CD co-monomer. A cationic or basic dyestuff contains amines or ammonium groups or quaternary nitrogen-heterocyclic. Dyeing CD-PET is an ion exchange process. The sodium cations (Na+) from CD-PET are substituted by the bigger dye cations, whereas the sodium ions enter into the dye bath. Thus, PET is chemically modified in a manner that cationic dyestuffs can form a chemical complex with the fibre that is as shown in the Figure:
The chemistry of producing CD-PET is complicated. The reason for difficulty is the acidic character of Na-SIPA, especially in connection with hydrolytic or glycolytic conversion. Therefore, after direct addition of this salt into the PET esterification stage, the diethylene glycol (DEG) would reach a high level because ether formation is acid-catalysed. Additionally, the acidic character enhances the TiO2 agglomeration. The result is difficulty in the spinning process, and an excessively low melting point of CD-PET.
Low pill PET (LP-PET):
Pilling is a serious problem, which is associated with all the synthetic fibres. In order to reduce the pilling, polyester fibres having lower than usual strength has been prepared. Although such fibres form pills due to friction, these pills can be removed by simple brushing since the fibres have lower strength.
The polyester fibre having pilling tendency can be obtained by incorporation in the polymerising mass, certain substances such as terepthalate of barium, calcium or zinc or organic compound of antimony, chromium or iron. Normally, the pilling resistance has been achieved by reducing the abrasion resistance so that the fibre breaks off before the formation of large pills.
Modifications for hydrophilicity
Various processes for making polyester fibres hydrophilic include special spinning, non-circular cross-section, multilayered structure, dyeing, finishing and plasma treatment. Some of the important modification approaches are discussed below in this section. A large number of additives are suggested for making polyester fibre hydrophilic. ICI have suggested the addition of 5 – 10% by weight of sodium sulphate as slurry in glycol during polymerisation. The particle size of sodium sulphate should be less than 3 microns.
Polyester filament having a moisture absorption capacity of at least 1% at 65% RH and 21° C and a water retention capacity of at least 15% is developed by adding a water soluble aliphatic polyamide to the polyester, spinning the mixture and washing out the added amide with water. The soil resistance property of polyester fibres can be enhanced by the addition of polyethylene glycol or tetraethyl ammonium perfluorooctane sulfonate to the melt before melt spinning.
During the last few years, considerable amount of research work has been done on producing hollow polyester fibres having micro crates (holes) on the surface. The hollow polyester fibre is produced by using specially designed spinnerets. Normally, four types of spinnerets are used for producing hollow fibres and the spinnerets are shown in the Figure.
Plug-in-orifice spinnerets Fig (A):
These spinnerets have a solid pin supported in the center of a circular orifice. The polymer is extruded through the annulus. With this spinneret design, it is generally necessary to incorporate a gas-forming additive in the polymer melt. The gas fills the core of the fibre as it emerges from the annulus and prevents collapse until the fibre solidifies.
Tube-in-orifice spinnerets Fig (B):
These spinnerets have a hollow needle or tube supported in the centre of the orifice. An inert gas or liquid is injected through the needle to maintain a tubular shape until the fibre solidifies or coagulates.
Segment arc spinnerets Fig (C):
These spinnerets have C shaped orifices. The polymer solution or melt welds into a tube after extrusion through the C shaped die. The gas required to keep the fibre hollow is drawn in through the gap in the extruded fibre upstream from the weld point.
Teijin is marketing such hollow fibre under the trade name Welkey. The mechanism of water absorption and water transport by welkey is schematically shown in the figure. The water absorbing mechanism has three steps. In first step, water attached to the side of fibre enters into the hollow section of the capillary through the penetrating holes.
In the next step, water from the penetrating holes goes to both sides of the hollow section by its capillary action. In the final step, total amount of water is absorbed into the hollow section where capillary migration is stopped by balance of tension from both sides Special spinning
Drawn polyester filaments are hydro fixed in water in the presence of specified surface-active agents. Hydro fixing place more quickly and a more stable pore structure is obtained. This is reflected in increased moisture uptake and a higher water retention capacity. The fibres retain their hydrophilic properties for a considerable period of time, even with repeated wearing and washing. A salt forming compound is added to the polyester spinning composition for the manufacture of flame resistant and hydrophilic polyester fibres.
The application of the plasma treatment has been demo started for the surface modification of various textiles. A lot of environmental and production problems can be solved by using a non-equilibrium low temperature plasma. The plasma process are dry ones and do not require water or non-aqueous solution. Promising applications of gas discharges plasma for the activation of chemical reactions in liquids have also been reported.
Wet ability of polyester has been increased by using oxygen or nitrogen plasma. Plasma- produced polar groups increase the surface free energy of the fibre and decreases the contact angle. The contact angle for water was found to decrease for PET after plasma treatment in oxygen and nitrogen, while the contact angle for cellophane increased. Such low temperature, low pressure plasma treatment is effective in inducing the high consumption of chemical wetting agents normally required chemical processing of textiles.
Antibacterial/deodorant polyester fibres
Comfort and protection are two very important aspects of textiles today. The increase in the health concern of the consumer has prompted a need for fabrics that can inhibit the growth of bacteria and other microorganisms, which can cause offensive odours, skin irritation, visual spoilage and disfiguring stains making garments unusable with regards to hygiene and aesthetics. Certain allergens can cause allergic reactions and asthma in humans. These microorganisms may develop from the spills of body fluids or medical liquids.
Antibacterial protection (additives) inhibits the growth of such bacteria and allergens. At the same time, providing an antibacterial protection, which must not alter fibre spinnability, main properties of the fibre as dye uptake, wear and abrasion resistance and other mechanical properties.
Features of the antibacterial fibres:
* Prevent development of microorganisms, which are responsible for bacterial contamination and unpleasant odours.
* Should maintain a high level of effectiveness throughout the life of the products.
* No reduction of antibacterial activity when subjected to dyeing and finishing process.
* Greater amount of active material exposed on the surface.
* Compatibility in blends.
* Withstand robust handling and abrasion without impaired performance.
Antibacterial effectiveness is guaranteed with improved hygiene, comfort and coolness augmented by properties of heat regulation and moisture transference, which leave the wearer’s skin dry and healthy.
Production of antibacterial fibres:
It is a common practice to give antibacterial properties to synthetic fibres, by adding organic additives combined with fibres in several ways. However, employing organic agents to provide antibacterial activity is to some extent unsatisfactory. This is because of their toxicity, lack of durability and poor resistance to heat. Organic compounds also pose problems in fibre production and present problems when worn next to skin. So, inorganic supports such as special zeolites or ceramic substrates containing Ag or Zn ions have been proposed.
Flame retardant (FR) polyester fibres
Fire accident generally results in considerable loss of life and property. The majority of fire accidents occur due to burning of textile fibres. Polyester fibre is flammable and can cause considerable injuries due to melting. The blends of polyester with cotton are highly flammable.
The flame retardant effect is achieved by the addition of special chemicals. Earlier, this was done by impregnating the finished fabric or by physically mixing an agent to the polymer-for instance during melt spinning.
Previously, components containing halogen, and above all bromine, were used. The effect of these substances was based on the halogen radicals interrupting the combustion chain reaction. However, as halogen enables the formation of highly toxic dioxins, the compounds used today contain phosphorus. Bromine compounds are efficient, flame retardant additives but their fastness to light is not always satisfactory. Chlorinated arylalkyl hydrocarbons and bis (2, 4, 6-trichloro phenyl) phthalate have been suggested.
A number of FR polyester fibres commercially available include: Dacron 900F, Heim (Toyobo Co) Tetoran Exter (Teijin), Trevia CS and Trevira FR, Toyobo GH, etc. A number of flame retardant additives used during the transesterification reaction in the PET or sometimes mixed with PET chips prior to extraction. The important ones are; Ttriphenlyphosphineoxide, 3, 5-dibromo-terephthalate, decabromodiphenyl ether, tribromodiphenyl, phosphinic acid derivative etc.
Silk like polyester
For centuries silk fabrics are considered to be most elegant and gorgeous textile materials. However, the production of silk fibre could not keep pace with increase in human population, and hence the price of silk is now beyond the reach of most of the people. When synthetic fibres were first developed it was thought that these fibres will be able to substitute silk. However, soon it was realised that these fibres have metallic lustre, papery feel and poor aesthetic value. Substantial amount of research work was carried out to make silk like synthetic fibres, which has resulted in the development of silk-like polyester fabrics.
The following factors should be considered in the production of silk like polyester:
* Fibre cross section to obtain the desired luster.
* Fine denier filament to obtain the desired feel.
Role of cross-section of the fibre
Modification of cross-section of the fibre allows engineering of surface properties in yarn and fabric. Many cross-section shapes are available; Circular, trilobal, pentalobal, octalobal, hollow, hexagonal, and other irregular shapes. For silk like polyester fibre circular, trilobal, tetralobal, C shape, V shape, and hollow cross-sections have been used. The most popular cross-section for silk like polyester is trilobal, which gives adequate lustre resembling that of silk. The type of cross-section can be coupled with amount of TiO2 in the fibre may result in “Milky” colours when the fabrics are dyed.
Role of average denier of the yarn
It plays a primary role in determining the stiffness of the yarn. It is easy to visualise its effect by an analogy, where a thin glass capillary is stiff and brittle, but when it is made in the form of the filament it is pliable. Silk fibres are “Very fine” in the range 1.2 to 1.3 dtex, and hence necessarily the synthetic fibre used to be in the same range or finer to obtain a feel closer to silk. Finer the single filaments in the yarn, the softer the hand of the resultant fabric. The larger the number of fine filaments in yarn of identical over all titer, and bulkier and denser the fabric hand.
Polyester: It is a well-known fibre in the synthetic fibre because it has certain desirable properties, the properties are high strength, wash and wear property, good dimensional property, elegant appearance and suitability for blending with cellulosic and protein fibres. But polyesters have some of certain drawbacks such as moisture regain, static electricity, soiling problem, difficult to dyeing, etc.
But now many more developments in the polyester processing, ie, hydrophilic polyester, easy dyeable and cationic dyeable polyester, low pilling, antimicrobial polyester, silk like polyester, etc. The advantages of above properties are good comfortable while in wearing, easy to dyeing, so it provides cost reduction and very good appearance of the polyester garments.
1. E P G Gohl and L D Vilensky: Textile Science, 2nd Edition, CBS Publishers, 1999.
2. S Jayaprakasm and R Gopalakrishnan: Fibre Science and Technology, S S M I T T Publication.
3. V A Shenai, Technology of Textile Processing; Textile Fibres, Sevak Publication, 1996.
4. S P Mishra, Text Book of Fibre Science and Technology, New Age International Publishing Co.
5. R M Mittal and S S Trivedi: Chemical Processing of Polyester/Cellulosic Blends, ATIRA Publication, 1983.
6. A A Vaidhya: Production of Synthetic Fibres, Prentice Hall of India Publications.
7. W Klein: Man-made Fibre and Their Processing, The Textile Institute Publication.
8. V K Kothari, Progress in Textiles: Science & Technology; Vol 2.
9. Premamoy Ghosh: Fibre Science & Technology, Tata Mc-Graw Hill Publishing Company.
10. Bernard P Corbman: Textile Fibre to Fabric, Mc Graw-Hill Publication.
11. Vaidhya A A, John Wiley and Sons: Chemical Processing of Man-made Fibres, New York, 1984.
12. Trotman E R and Charis: Dyeing Chemical Technology of Textile Fibre, Graffin & Company, UK.
13. Holme I: Developments in Chemical Finishing of Textiles and Apparel, Textile Outlook International, March 2001.
14. Holme I, Recent Advances in Chemical Processing, International Conference on Recent Advance in Wet Processing in Textiles, BTRA Publications.
15. Yair Avny and Ludwig Rebenfeld: Chemical Modification of Polyester Fibre, Journal of applied Polymer Science, Vol 32, Issue 3, pp 4009-4025.
16. Martin Bide et al: Modified fibres with Medical and Speciality Application, http://www.sprinklink.com/content/l042vo14uh874514.
17. Easy Cationic Dyeable Polyester, http://www.cyarn.com/products/fibre/fibre-018.html.
18. V K Kothari et al: Journal of Applied Science, Vol 61, Issue 3, pp 401-406. http://www3.interscience.wiley.com/cgi-bin.
19. Properties of Modified Polyester Fibre, Textile Research Journal, http://www.trj.sagepub.com/cgi/content.
21. Polyester Fibre & Method of Production, US Patent No: 4526738, http://www.freepatentsonline.com/4526738.html.
Note: For detailed version of this article please refer the print version of The Indian Textile Journal June 2009 issue.
Aravin Prince P
JKK Muniraja Polytechnic, Gobi, Tamil Nadu.
Mobile: 097900 80302.
Engineered Plants Make Potential Precursor to Raw Material for Plastics
ScienceDaily (Nov. 9, 2010)
Engineered Plants Make Potential Precursor to Raw Material for Plastics
Researchers report engineering a plant that produces industrially relevant levels of compounds that could potentially be used to make plastics. (Credit: Image courtesy of DOE/Brookhaven National Laboratory)
In theory, plants could be the ultimate “green” factories, engineered to pump out the kinds of raw materials we now obtain from petroleum-based chemicals. But in reality, getting plants to accumulate high levels of desired products has been an elusive goal. Now, in a first step toward achieving industrial-scale green production, scientists from the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory and collaborators at Dow AgroSciences report engineering a plant that produces industrially relevant levels of compounds that could potentially be used to make plastics.
The research is reported online in Plant Physiology, and will appear in print in the December issue.
“We’ve engineered a new metabolic pathway in plants for producing a kind of fatty acid that could be used as a source of precursors to chemical building blocks for making plastics such as polyethylene,” said Brookhaven biochemist John Shanklin, who led the research. “The raw materials for most precursors currently come from petroleum or coal-derived synthetic gas. Our new way of providing a feedstock sourced from fatty acids in plant seeds would be renewable and sustainable indefinitely. Additional technology to efficiently convert the plant fatty acids into chemical building blocks is needed, but our research shows that high levels of the appropriate feedstock can be made in plants.”
The method builds on Shanklin’s longstanding interest in fatty acids — the building blocks for plant oils — and the enzymes that control their production. Discovery of the genes that code for the enzymes responsible for so called “unusual” plant oil production encouraged many researchers to explore ways of expressing these genes and producing certain desired oils in various plants.
“There are plants that naturally produce the desired fatty acids, called ‘omega-7 fatty acids,’ in their seeds — for example, cat’s claw vine and milkweed — but their yields and growth characteristics are not suitable for commercial production,” Shanklin said. Initial attempts to express the relevant genes in more suitable plant species resulted in much lower levels of the desired oils than are produced in plants from which the genes were isolated. “This suggests that other metabolic modifications might be necessary to increase the accumulation of the desired plant seed oils,” Shanklin said.
“To overcome the problem of poor accumulation, we performed a series of systematic metabolic engineering experiments to optimize the accumulation of omega-7 fatty acids in transgenic plants,” Shanklin said. For these proof-of-principle experiments, the scientists worked with Arabidopsis, a common laboratory plant.
Enzymes that make the unusual fatty acids are variants of enzymes called “desaturases,” which remove specific hydrogen atoms from fatty acid chains to form carbon-carbon double bonds, thus desaturating the fatty acid. First the researchers identified naturally occurring variant desaturases with desired specificities, but they worked poorly when introduced into Arabidopsis. They next engineered a laboratory-derived variant of a natural plant enzyme that worked faster and with greater specificity than the natural enzymes, which increased the accumulation of the desired fatty acid from less than 2 percent to around 14 percent.
Though an improvement, that level was still insufficient for industrial-scale production. The scientists then assessed a number of additional modifications to the plant’s metabolic pathways. For example, they “down-regulated” genes that compete for the introduced enzyme’s fatty acid substrate. They also introduced desaturases capable of intercepting substrate that had escaped the first desaturase enzyme as it progressed through the oil-accumulation pathway. In many of these experiments they observed more of the desired product accumulating. Having tested various traits individually, the scientists then combined the most promising traits into a single new plant.
The result was an accumulation of the desired omega-7 fatty acid at levels of about 71 percent in the best-engineered line of Arabidopsis. This was much higher than the omega-7 fatty acid levels in milkweed, and equivalent to those seen in cat’s claw vine. Growth and development of the engineered Arabidopsis plants was unaffected by the genetic modifications and accumulation of omega-7 fatty acid.
“This proof-of-principle experiment is a successful demonstration of a general strategy for metabolically engineering the sustainable production of omega-7 fatty acids as an industrial feedstock source from plants,” Shanklin said.
This general approach — identifying and expressing natural or synthetic enzymes, quantifying incremental improvements resulting from additional genetic/metabolic modifications, and “stacking” of traits — may also be fruitful for improving production of a wide range of other unusual fatty acids in plant seeds.
This research was funded by the DOE Office Science, and by The Dow Chemical Company and Dow AgroSciences.
Solar Industry Soars – Photovoltaics Sees 50% Growth in 2010
DuPont News, April 28, 2010
DuPont expects its photovoltaic sales to grow more than 50% this year as the solar industry experiences strong growth from increased market demand for new installations in Europe, North America and parts of Asia. DuPont now expects its sales into photovoltaics to exceed $1 billion in 2011, which is a year ahead of plan, and has set a new goal to exceed $2 billion in sales by 2014.
“Our focus on delivering materials innovations that are essential to the photovoltaic industry’s future growth is paying off for our customers and for DuPont,” said Dave Miller, president, DuPont Electronics & Communications. “We not only have the materials
that provide superior performance and reliability to photovoltaic modules, but also the ability to match those products to the specific, individual needs of our customers. Weare aggressively expanding to supply those materials in the volumes required by this high growth industry.”
In 2009, DuPont sales to the photovoltaic market exceeded $550 million – an increase of more than 25% from the previous year – and outperformed the broader industry which experienced significantly lower growth. DuPont’s growth is supported by new innovations that improve module efficiency and lifetime and enable new photovoltaic technologies and applications, which ultimately accelerate the industry’s drive to bring costs down in line with other forms of energy.
DuPont is a leading material and technology supplier
to the photovoltaic (PV) industry, with more than 25
years of experience in PV materials development,
applications know-how, manufacturing expertise and
global market access.
“We have seen strong demand that has led us to continue our trend of growing faster than the market due to several successful new product introductions and share gains based on a strong portfolio of materials-based offerings to global photovoltaic cell and module manufacturers,” Dave said. “We expect our growth momentum to continue because materials innovations are essential to delivering improved efficiency, longer lifetimes, and lower overall system costs to consumers.”
Save water when dyeing with Fongs technology
March 17, 2010 (Hong Kong)
In 1992, the United Nations General Assembly designated 22nd March as “World Water Day”. Every year on that date, people worldwide participate in events and programs to raise public awareness about the critical lack of clean and safe drinking water supplies-and to promote the conservation and development of global water resources.
The textile industry consumes huge volume of water everyday and the dyeing industry is undoubtedly one of the industrial sectors that threatens the safety of drinking water. In an effort to save the precious water resource and reduce the environmental impact, Fong’s Industries Group along with its member companies, namely “Fong’s National”, “THEN”, “Goller” and “Fong’s Water Technology” provide an ecological dyeing solution to reduce the water consumption drastically through their innovative technologies covering the processes from yarn dyeing to piece dyeing and recycling of discharge after dyeing and finishing.
1.Yarn Dyeing Process – Fong’s ALLWIN High Temperature Package Dyeing Machine:
Yarn dyeing is nothing more than imparting colour to the yarn that will soon be used in knitting or weaving projects, however, it consumes an enormous quantity of water and electricity at the dye houses, which impels the industrial manufacturers to find an environmental solution to revitalize their competitiveness.
Fong’s ALLWIN High Temperature Package Dyeing Machine offers an unprecedented liquor ratio as low as 1:4 with its integrated design of REV centrifugal pump, heat exchanger and the flow reversing system (patent granted). The newly designed integrated circulating system results in space saving by approx. 25% as compared with conventional machine arrangements.
With the capacity ranging from 28 kg to 9129 kg, ALLWIN is equipped with AIR+ Advanced Intelligent Rinsing System, which shortens the processing time for cotton yarn to 276 minutes, the total water and electricity consumption for dyeing medium to dark shade yarns are reduced to 34l/kg and 0.43kWh/kg respectively, consequently a significant saving on water and electricity consumption by over 40% and chemical cost by 19% as compared with conventional machines.
The ILC Intelligent Levelling Control System monitors the water flow through the package from outside-in to inside-out and vice versa. The ILC improves the levelling of colour through out the whole package thereby reduces yarn loss and increases reproducibility from batch to batch. The outstanding performances of these features save total production cost by 30%, making it a premium choice for yarn dyeing facilities everywhere.
2. Discontinuous Dyeing Processing – Overflow and Airflow Dyeing Machines:
(1) Fong’s Jumboflow High Temperature Dyeing Machine –
Despite the new technologies being introduced to the industry over the past 2 decades, the overflow dyeing machines are still being widely used in the knitted fabrics segment nowadays. Fong’s National has constantly endeavored on the product development and research to meet the great demand from the customers for eco-friendly dyeing machines with low water and energy consumption to face the rising competition in the textile sector.
Recognizing this market demand, Fong’s National has launched latest JUMBOFLOW series High Temperature Dyeing machines, which are the most economic hydraulic dyeing equipment ever developed for the industry. It is suitable for the processing of light to heavy weight fabrics with the lowest liquor ratio of 1: 4.5 to run the machine.
The JUMBOFLOW series machine is rigged with the Multi Saving Rinsing System (MSR), which allows the dyeing process to carry out cooling and rinsing simultaneously. For those dye houses without recycling of cooling water, MSR reuses the cooling water discharged from the heat exchanger directly and carries it back to the machine for the rinsing purpose. This avoids the direct discharge of the cooling water and hence reduces the water consumption considerably.
In order to rinse fabric effectively, the quantity of rinsing water and the rinsing time must be controlled, the AIR+ Advanced Intelligent Rinsing System is developed for this purpose to improve the rinsing efficiency. With the aid of flowmeter and modulation valve, the flow rate of filling water can be controlled automatically. During the rinsing process, the conductivity of the electrolytes in the dye liquor (in ppm) is actively monitored.
The rinsing process continues until it arrives at a particular TDS (total dissolved solids) value (standard before soaping: 2000ppm = 2g/L Na2SO4). As the usage of the alkaline is directly proportional to the TDS value, and the TDS value is also proportional to the usage of acetic acid, according to the Equivalent Weight Principle, it does not only guarantee the performance of neutralization by acetic acid, but also save water consumption and process time by approximately 40% and 33% respectively as compared of these with conventional dyeing machines.
(2) THEN-AIRFLOW® Dyeing Machine –
The researchers at THEN had already predicted the situation of increasing scarcity of usable water as far back as the 1970s, when they began developing a jet dyeing system that would dramatically save water. The basic idea was to use dye liquor for the sole purpose of dyeing the fabric, and not to waste copious amounts of it to simply move the fabric through the kier.
They achieved this by harnessing the air inside the dyeing vessel and use it as a jet stream to propel the fabric through the dyeing nozzle. Thus, the THEN-AIRFLOW® concept was born, and it became an immediate success initially in Europe and America in the 80s and 90s of the last century. Today, the global success story of the THEN-AIRFLOW® continues, and it has become the most popular brand of exhaust dyeing machines even in China.
As air is used to move the fabric through the machine, the liquor ratio required in THEN-AIRFLOW® machines is typically 30 to 50% lower than in hydraulic round vessel dyeing machines. For 100% cotton fabrics, it is typically 1:3.75 at full loading, and even at half loading, 1:4.6 is achievable, as the THEN-AIRFLOW machine works without a liquor bath in the bottom of the kier.
The significantly lower amount of water in circulation also means considerably lower requirements of auxiliary chemicals and, in reactive dyeing, particularly of Glauber’s salt. Dyeing of most synthetic fabrics can be effected without the use of anti-foaming agents.
Over and above this, the lower liquor ratio also offers a higher efficiency of dyestuffs. In THEN-AIRFLOW® technology, the dyeing point is in the nozzle. By injecting the dyeing liquor into the airstream transporting the fabric through the nozzle, an aerosol mist is created that offers dyestuff penetration far beyond the reach of any dye bath. In reactive dyeing, customers achieve annual savings of around 5% on their dyestuffs bill.
The low liquor ratio and low overall water consumption also mean that total cycle times are greatly reduced. For a 100% cotton fabric in a dark red (maroon) shade, the total process time including loading, pre-bleaching, reactive dyeing, washing-off, rinsing and unloading is 278 min. This means a theoretical batch rate of 5.2 per day and thus a massive improvement in productivity over old technology. The overall water consumption for this fabric from loading to unloading is 39 l per kg.
In pure bleaching operations, THEN-AIRFLOW® machines achieve water consumption figures of 8 l per kg for RFD (ready-for-dyeing) and 9 l per kg for optical white.
THEN-AIRFLOW® machines are available as high-temperature models or as atmospheric machines. There are presently more than 2,500 units of late design in operation worldwide, offering their respective owners economic and ecological superiority on both woven as well as knitted fabrics across all natural and man-made fibre contents.
THEN-AIRFLOW technology is unrivalled as the most economical exhaust dyeing technology and the most ecologically sound solution in the industry: it offers the smallest water footprint of any exhaust technology available today.
3. Continuous Wet Processing – Goller Colora Dyeing Range –
Goller has been a leading manufacturer of continuous wet finishing lines for woven and knitted fabrics, for a long time. Compared to discontinuous processing machines, it is evidenced that all Goller products have a lower consumption of water, steam and chemicals. This is also valid for the dyeing process of wovens on the pad steam range Colora as well as for our washing range Sintensa for knits after CPB dyeing.
In order to protect the environment and to save previous resources, we are trying to reduce the water consumption as far as possible. Especially in the field of intensive R&D we made a lot of progress. All ranges of Goller are equipped with a state-of the-art computer program, which controls and regulates the whole setting of the machine.
For Goller it is self understanding that also the liquor content in the different washing compartment is reduced to the absolute necessary minimum. This is important when the production line has to be emptied and refilled when changing the colour which has to be dyed / when changing the colour for dyeing process. This means that in the Effecta compartments for woven fabrics the bottom guide rollers are submerged only by 2/3 of its diameter.
Besides the reduced filling quantity it also optimises the usage of the water. Between guide roller and fabric a hydrostatic pressure is created which increases the crossflow through the fabric and increases thus the washing efficiency. In the Sintensa compartments for knitted fabrics where the fabric is carried through the compartment, this crossflow is created by mechanical means. A driven rotor with a special surface shape pushes the washing liquor through the fabric.
Another important feature to save water is the consequent counterflow inside the washing compartments. Through meandering cascades it is made sure that no dead zones exist and no accumulation of impurities or concentration differences occur. Depending on the dyeing process this counterflow is also applied between different compartments.
With the consequent reduction of process water the side effects are obvious: Less energy is needed to heat the process water which in a dyeing range requires up to 98°C. Thus costly energy is saved at the same time, but also less water to the drain means less treatment costs for the effluents.
Huge potentials for savings exist nowadays in the continuous finishing of knits, which is not so common yet. Goller is supporting especially these customers with technological and technical support to achieve the potential savings for the benefit of the customers but last not least for the environment.
4. Reduce Discharge from the Start till the End – Fong’s Water Technology’s Water Reuse System:
Despite all the innovative ecological dyeing systems being provided, water consumption in dyeing process is still large. It would be best to treat discharge can then be used back into the dyeing process, lowers new fresh water intake and the discharge volume.
Since the water used in textile manufacturing must be non-staining, water to be reused must be low in turbidity, colour, iron, and manganese. Hardness may cause curds to deposit on textiles and causes problems in processes that use soap. As such water to be reused must first go through a desalination process that reduces its hardness and impurities. Reverse osmosis, an advanced treatment process materialised through modern-day membrane technology, is most commonly used in water reuse to physically remove salt and impurities from wastewater.
Water Reuse systems provided by Fong’s Water Technology has unique characteristics and advantages in water impurities removal. Membranes, used with the combination of other traditional filtering processes, can efficiently retain microscopic elements, and lowers the content of organic materials, colour, water hardness and other undesirable substances in wastewater.
As the membrane technology matures, cost of membrane element has decreased while the performance of such increased. Treated water can readily be reused in production, reducing water costs, discharge costs, hence reducing operating costs-
Installing a water reuse unit is definitely not a plug-n-play business, and need a tailor-made solution to ensure optimal performance. The implementation of water reuse system is in 3 phases:
1.Preliminary water test: Around 2 to 3 Litres of water sample is collected for water quality analysis. A few characteristics of the effluent are evaluated, including conductivity, total dissolved solids (TDS), pH, Colour, Turbidity, and Chemical Oxygen Demand (COD).
2.Pilot Test: With the pilot test unit running in client’s site for around one month, it should cater most of the challenges that the full system may encounter, and engineers collect the information needed for fine-tuning the proposed solution hence provide a better final implementation for the customers.
3.Full implementation: With the water sample analysis and pilot test carried out, it should now pretty confident that the final solution will operate in an effective and efficient manner.
5.Gearing Up for Future Challenge:
The issue of water and energy savings is currently a hot topic worldwide, the discussion has been also very much in vogue in textile industry. The fierce market competition nowadays has resulted in a lower profit margin in the dyeing and finishing industry. To stay competitive, the manufacturers have become much more environmentally conscious than ever and started to apply the innovative product technology to reduce their water and energy consumption, thus, help to slow down climate change.
Looking ahead, Fong’s Industries Group will uphold its commitment to serve the industry with the best environmental solution covering the quality products and cutting-edge technology to help the industrial manufacturers to achieve the balance between the operating target and environmental stewardship.
Fong’s Industries Group
Electron beam facility to treat textile polluted water
April 03, 2009 (Sri Lanka)
The textile and agreement industry in Sri Lanka has always been in the forefront of eco-friendly and sustainable methods of manufacturing. Many of their companies like Brandix and MAS holdings have received innumerable awards for creating clothing with eco-friendly processes.
Taking the process further, the Atomic Energy Commission in close cooperation with the Central Environmental Authority is conducting a feasibility study on treating the deadly chemical water released by the textile dyeing units with means of an Electron Beam Facility.
The International Atomic Energy Agency in Vienna has agreed to provide technical assistance for technology transfer and an expert, Dr. Bumsoo Han from Korea is in Sri Lanka to conduct a feasibility study of the project and to create awareness among industrialists about this technology.
Dr. Bumsoo Han was earlier associated with a pilot plant for treating 1,000m3/day of dyeing wastewater with e-beam which had been constructed and under operation since 1998 in Daegu, Korea together with the biological treatment facility.
The Electron Beam facility basically treats the polluted water with help of e-beam and helps treat water with increased reliability and helps in decolorizing and destructive oxidation of organic impurities in wastewater with reduction in treatment time and an increase in flow rate limit by 30-40 percent.
PETG : PET modified by copolymerization is available
In some cases, the modified properties of copolymer are more desirable for a particular application.
For example, cyclohexane dimethanol (CHDM) can be added to the polymer backbone in place of ethylene glycol. Since this building block is much larger (6 additional carbon atoms) than the ethylene glycol unit it replaces, it does not fit in with the neighbouring chains the way an ethylene glycol unit would.
This interferes with crystallization and lowers the polymer’s melting temperature. Such PET is generally known as PETG (EastmanChemical and SKchemicals are practically the only two manufacturers).
Another common modifier is isophthalic acid (IPA), replacing some of the 1,4-(para-) linked terephthalate units. The 1,2-(ortho-) or 1,3-(meta-) linkage produces an angle in the chain, which also disturbs crystallinity.
This copolymer is mainly used for bottle production .
The niche more interesting price is the kind with CHDM .
CHDM is very expensive both for price and quantity.
Some producers are trying to produce PETG without CHDM , replacing it with inexpensive glycol to dramatically end price reduce.
But , there are not negligible problems of performance .