This document discusses bleaching, semi-bleaching, and optical brightening agents used in the textile industry. It defines bleaching as removing natural color from fibers through chemical processes that break double bonds in color molecules. Semi-bleaching uses hydrogen peroxide, which keeps fiber quality intact. Optical brightening agents absorb ultraviolet light and re-emit blue light, making whites appear brighter by masking the yellowness of fibers. The document provides examples of oxidizing and reducing bleaching agents and explains how optical brighteners work to enhance the brightness of bleached fabrics.
Hello there,
This ppt is about basic information of application of direct dye on cotton fibre .
Hope it will be helpful to you .
Please give feedback in comment section regarding any mistakes or corrections.
If you have any query please feel free to ask in comment section.
Reference -NCUTE, Textile dyes , Dyeing of synthetic and industrial fibre vol 2
Thanks !
Softener is an finishing agent that when applied to textile material improves its handle giving pleasing touch. As a general rule, the softening agents applied are lubricating agents, which facilitate the fiber sliding within the fabric structure, thus granting easier deformation and creasing of the fabric.
Hello there,
This ppt is about basic information of application of direct dye on cotton fibre .
Hope it will be helpful to you .
Please give feedback in comment section regarding any mistakes or corrections.
If you have any query please feel free to ask in comment section.
Reference -NCUTE, Textile dyes , Dyeing of synthetic and industrial fibre vol 2
Thanks !
Softener is an finishing agent that when applied to textile material improves its handle giving pleasing touch. As a general rule, the softening agents applied are lubricating agents, which facilitate the fiber sliding within the fabric structure, thus granting easier deformation and creasing of the fabric.
Scope of Dyeing Polyester Cotton (PC) Blended Fabric in Single Bath Process f...iosrjce
Dyeing of fabric blends such as Polyester/Cotton (P/C) is presently done with two
chemically different classes of dyes namely disperse for polyester and reactive for cotton, in
two bath process. Experimental work was carried out on finding the possibility of dyeing the
P/C blends in one bath process without drain the liquor after polyester part dyeing. All the
existing chemical and conventional temperature range were applied in this study. The result
indicates that, the using of one bath method in the polyester cotton dyeing can slightly change
the fastness properties than the conventional method. The one bath dyeing method showed
level dyeing having good fastness properties and offers the option of cost effective and ecofriendly
dyeing process.
We are Textile Engineer, we only apply dyes and pigment on textile substrate but we need to know how dyes and pigment manufacturing. I have details about all dyes manufacturing.
Washing is the most rising sector in Bangladesh now a days..All fashionable and fancy styles are achieved through wash in apparels...Washing either a glory nor a magic....
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
How to Make a Field invisible in Odoo 17Celine George
It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
A Strategic Approach: GenAI in EducationPeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Francesca Gottschalk - How can education support child empowerment.pptxEduSkills OECD
Francesca Gottschalk from the OECD’s Centre for Educational Research and Innovation presents at the Ask an Expert Webinar: How can education support child empowerment?
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
2. BLEACHING
Bleaching is chemical treatment employed for the removal of
natural colouring matter from the substrate. The source of
natural colour is organic compounds with conjugated double
bonds , by doing chemical bleaching the discoloration takes
place by the breaking the chromosphere , most likely
destroying the one or more double bonds with in this
conjugated system. The material appears whiter after the
bleaching.
In simple terms it is the process of removing paleness from
natural fibres like cotton, wool, linen etc. are off-white in
colour due to colour bodies present in the fibre. The degree
of off-whiteness varies from batch-to-batch. Bleaching
therefore can be defined as the destruction of these colour
bodies.
3. Purpose Of Bleaching
Removal of coloured impurities.
Removal of the seed coats.
Minimum tendering of fibre.
Technically reliable & simple mode of
operation.
Low chemical & energy consumption.
Increasing the degree of whiteness
5. Oxidative Bleaching Agents
Reductive Bleaching Agents
Enzymatic Bleaching Agents
Type of Bleaching Agents
A bleaching agent is a substance that can whiten or
decolorize other substances. Bleaching agents essentially
destroy chromospheres (thereby removing the colour),
via the oxidation or reduction of these absorbing groups.
Thus, bleaches can be classified as either oxidizing
agents or reducing agents .
Bleaching Agent
6. Oxidizing bleaching agents:
Generally oxidative bleachings are carried out hypochloretes, sodium chlorite
or peroxy compounds. Natural fibres like cotton, ramie, jute, wool, bamboo
are all generally bleached with oxidative methods. The double bond breaks in
the oxidative bleaching, which makes the substrate colourless.
Example:
Na-hypochlorite (NaOCl), Ca-Hypochlorite [Ca(OCl)],
Hydrogen peroxide (H2O2), Ozone (O3)
Reducing bleaching agents:
Reductive method of bleaching is done with sodium hydrosulphite sodium
sulphide and sulphur dioxide are powerful reducing agents. Fibres like
polyamide, Polyacrylics and Polyacetates can be bleached using reductive
bleaching technology. Double bond is converted into single bond in case of
reductive bleaching.
Example:
Carbon monoxide (CO), Hydrogen sulphide (H2S), Zinc dust (Zn)
Sulphur di-oxide (SO2), Sodium bi-Sulphate (NaHSO4)
7.
8. SEMI BLEACHING
Bleaching of textiles with Hydrogen Peroxide is known as semi bleaching.
Advantages of Peroxide Bleaching:
Among the oxidizing bleaching agents, only hydrogen peroxide provides a high
bleaching effect at reasonable costs, especially if modern short-term bleaching
processes are used with only a few minutes bleaching time.
Peroxide bleaching keeps the fibre quality intact.
Cotton can be bleached with peroxide in a single stage. Other processes require
two or three bleaching stages,(desize with scour, scour with bleach and desize
with scour and bleach).
No separate pre treatment is necessary because hot, alkaline bleaching has not
only a bleaching but also a cleaning effect, it therefore combines the advantages
of an alkaline extraction with the bleaching treatment.
Animal fibres can only be bleached with peroxide to a high and stable degree of
whiteness.
Corrosion of stainless steel equipment does not occur during peroxide bleaching.
9. Optical Brightening Agents (OBAs)
Optical brighteners, optical brightening agents (OBAs), fluorescent
brightening agents (FBAs) or fluorescent whitening agents (FWAs)
are chemical compounds that absorb light in the ultraviolet and
violet region. These additives are often used to enhance the
appearance of colour of fabric and paper, causing a "whitening"
effect.
OBAs are used to make white coloured or light coloured fabrics
brighter. Mostly bleached white fabrics are treated with these
brighteners.
Optical brighteners have the property of absorbing ultra violet
(U.V) light and re emit energy in the form of weaker energy that is
visible light ( blue light) so that the yellow colour of material
appears white.
10. Optical brighteners aren’t effective unless they remain in the
fabric, and persist after washing. They only last so long, until the
point when they actually burn out and no longer do anything. They
are also subject to fading when exposed long term to UV.
Optical brighteners are synthesized from various chemicals. The
group of chemicals which are called “optical brighteners” consists
of approximately 400 different types.
TEXTILE BRIGHTENERS
UJALA(4 drops only)
Most commonly used
optical brighteners
domestically to keep your
“WHITES” white and
bright for long time.
11. WORKING OF OPTICAL BRIGHTENERS
The sun rays have Ultra Violet (U.V)
rays and due to treatment of
optical brightening agents (OBA’S)
on white fabrics they reflect U.V
rays and the fabric appears to be
white and bright.
Ultra violet rays converts to white
light, when gets into prism.