CSRTI-Bangaluru

CENTRAL SILK TECHNOLOGICAL RESEARCH INSTITUTE, BANGALURU
How to know the quality of cocoons?

The most important quality indicators are uniformity in shape, size and fewer defective cocoons. Another important factor is ‘reelability’ which of course can be ascertained by a detailed testing procedure.
What is optimum drying of cocoons?

In optimum drying of cocoons entire moisture from the pupa is removed during drying.
Is the hot air-drying of cocoons the best practice?

Yes, the hot air drying not only kills the pupae but also removes the moisture from the cocoons and hardens the sericin which can be stored for a longer period.
How does the sorting of cocoons help?

Sorting of the cocoons using cocoon-sorting table helps to remove the defective cocoons, which otherwise affect the quality of raw silk.
Does the cooking procedure differ for different types of cocoons?

Yes, depending upon the shell thickness, the cocoons shall be cooked with retting treatment, high permeation treatment, low permeation treatment, cooking treatment and finishing treatment at suitable temperatures for specified duration
How the reeling speed affects the silk quality?

There is a threshold in reeling speed beyond which the cocoons at each end in a basin cannot be maintained effectively by the reeler, which inturn affects the quality of silk. The optimum reeling speed is determined based on the non-breakable filament length. For e.g. While reeling 20/22 denier silk from cocoons having non-breakable filament length of 700 m the reeling speed recommended is 100 m/min.
What is the purpose of croissure?

The croissure removes the excessive moisture from the yarn, binds the filaments together and induces a circular cross section to the yarn.
What is the correct way of removing the skeins from re-reeling machine?

The silk skeins have to be laced properly and the first and the last ends are to be tied along with the lacing thread. Utmost care has to be taken to see that the threads are not cut in the process of removal.
What is the correct way of removing the skeins from re-reeling machine?

The silk skeins have to be laced properly and the first and the last ends are to be tied along with the lacing thread. Utmost care has to be taken to see that the threads are not cut in the process of removal.
How to lace the silk?

The silk threads should be laced with a cotton thread at six places in the form of a loop. It also avoids entanglement of the yarn.
Are there any specific advantages of long skeining?

The long skeining avoids mis-handling of raw silk. Silk threads in a long skein are not strained due to folding.
How to avoid corkscrews in the yarn?

Take proper care during doubling. Maintain uniform tension on the individual yarns being plied.
How to avoid end breaks during re-reeling?

The end breaks are often caused by gummed threads and are formed due to condensate/water droplets falling on the yarn during steaming. Use of convex/ dome shaped lid for the steaming chamber will be helpful.
How to identify the direction of twist?

Hold the two ends of the yarn vertically straight with the thumb and forefinger. Turn the top end of the yarn towards you keeping the other end constant. If the yarn untwists, then it is ‘Z’ twist, else it is ‘S’ twist.
What should be the level of twist for primary and secondary twisting of organzine yarn?

Primary twist must be given in ‘Z’ direction with 800 TPM and secondary twist should be in ‘S’ direction with 700 TPM.
Why we find powder deposits on the machine during winding, doubling and twisting?

It may be due to racial character of silk. It may also be due to the yarn getting abraded in its path and depositing as powder, which in reality is not a powder, but are the bits of fibre.
Why is the problem of yarn breakage more severe during summer?

It is mainly due to low humidity level in the air. During twisting, it is required to maintain a humidity level of 65 to 70 per cent for best results.
How the hardness of water affects dyeing?

• Hard water causes excess consumption of soap and soda. Thus proper degumming will not take place with the prescribed recipe.
• There is excess consumption of dye stuff and chemicals resulting in uneven dyeing.
• On the whole, the cloth appears rough and dull.
How crucial is the gradual increase of temperature in case of acid dyeing?

Since some colours like acid yellow and black react with silk at lower temperature, it is advised to enter/dip the material at around 40ºC. However, as the dye fixation takes place at higher temperature, it is advised to increase temperature gradually to higher level.
What is the role of glauber salt in dyeing?

Silk is having lot of affinity for acid dyes resulting in uneven dyeing. This can be avoided by adding glauber salt in dye bath which retards the rate of reaction/absorption, hence uniform dyeing is facilitated.
Why acetic acid is added in silk dyeing with acid colours?

Acetic acid is added in the beginning to maintain the required acidic pH in dye bath.
What precaution one has to take during single bath degumming and dyeing process?

In order to ensure dye bath pH to turn from alkaline to acidic medium, acetic acid is added to dye bath.
What is the quantity of water that is required for dyeing?

Quantity of water required for dyeing is dependent on two factors
Type of machine used 
      For tub dyeing - 1:30*
      For Arm dyeing-1:12(minimum 80 litres)

Type of shade required 
       For light shade - 1:40 
       For medium shade - 1:30
       For dark shade- 1:20
*The ratios as above are based on weight of material to weight of water
What is the effect of manual squeezing?

The wet strength of silk is less and hence any rough handling like squeezing weakens the yarn further and increases the number of breaks during weaving.
How to check the pH in degumming and dye bath?

pH can be checked by using appropriate pH papers or pH meters.
Why local soap cannot be used?

Soap used for degumming should be neutral in nature, as there is less chances of getting local soap being neutral in nature. It is advisable not to use the locally available soap.
How to assess the degumming performance?

By actual estimation of loss in weight after degumming.
What is meant by temporary finish and durable finish?

Finish that does not remain after washing is known as temporary finish. On the other hand, the finish which is retained even after washing is known as durable finish.
What is waterproof finish?

This finish is obtained by treating the fabric with formaldehyde resin to prevent the penetration of water.
What is waterproof finish?

This finish is obtained by treating the fabric with formaldehyde resin to prevent the penetration of water
How to improve fastness in case of dyeing and printing?

Ensure complete degumming. Use standard/branded dyestuff and chemicals. Allow sufficient time for dye exhausting as per procedure.
How to improve crease recovery in silk fabrics?

By giving anti crease finish, crease recovery property can be improved.
What is it due to unevenness in the form of pale portion, spots on the printed fabric?

Reason: This is because of presence of residual gums, soap, paraffin or starch on the material
Remedy: Care should be taken in pre-treatment of the fabric
What is it due to unevenness in the form of colouring and rough prints on the printed fabric?

Reason: This is because of in adequate pre-treatment and unsuitable thickener, dyes and colour foams
Remedy: Give proper pre-treatment, wash the material properly, use defoamer and dissolve the dyes properly.
What is it due to unevenness in the form of colour becoming darker/lighter towards one side?

Reason: It is because of uneven pressure when applying colour and uneven steaming.
Remedy: Check printing paste application and steam circulation.
What is it due to un-levelness in the form of two sidedness on the printed fabric?

Reason: It is due to uneven migration of dyes in combination during drying and/or steaming.
Remedy: Select dye mixture element with same migration behaviour.
What is it due to sharpness of prints in the form of prints tending to flush?

Reason: It is because of usage of too much solvent, low viscosity of the printing paste and also due to improper steaming.
Remedy: Reduce use of solvent to minimum level, use more thickener in body and check steam inlet.
What is it due to sharpness of print in the form of halo in discharge printing?

Reason: It is due to the usage of too much of discharging agent or due to solvent used coupled with moist steaming and low viscosity of the printing paste
Remedy: Change the printing recipe
What is it due to colour discharges result in pale?

Reason: Over reduction because of printing paste containing excess reducing agent or over reduction during steaming.
Remedy: Add discharging chemicals first before printing, use calcium formaldehyde sulphoxylate as discharging agent.
What is it due to irregular discharged portion?

Reason: It is due to partially degraded discharging agent coupled with poor and very slow drying
Remedy: Dry the fabric completely, immediately after printing
What is it due to specks in the print motifs?

Reason: It is due to undissolved dye particles or due to dye precipitation in the printing paste.
Remedy: Dye character to be analyzed and prepare the printing paste accordingly.
What is it due to heavily chafed portion?

Reason: Split thread because of mechanical process gives raise to this defect particularly in winch dyeing machine.
Remedy: Keep waste on running fabric and ensure gentle mechanical treatment.
FAQs on  Catalytic Development Schemes of Post Cocoon Sector
Who can apply for Catalytic Development Schemes ?

Any new entrepreneur
Any existing entrepreneur 
Any beneficiary under earlier CSB schemes but not defaulted.
Can an entrepreneur apply for more than one scheme?

Yes, an entrepreneur can apply for more than one scheme provided he fulfills the eligibility criteria.
Is there any subsidy for land and building?

Subsidy is available for machineries only and not for land or building.
Whom to apply ?

As the XI plan schemes are implemented and monitored by different CSB Zonal officers, you may forward your duly filled application form to respective CSB Zonal offices as per the following table.

If the beneficiary belongs to May forward the application to
Karnataka, Goa CSTRI, Bangalore
Andhra Pradesh SCTH, Dharmavaram
Tamil Nadu, Kerala, Puducherry, Andaman Nicobar SCTH, Kancheepuram
Uttar Pradesh, Bihar, Uttarakhand, Jharkhand, TTL, Varanasi
Chhattisgarh, Madhya Pradesh, Maharastra, Orissa, Gujarat ZO, Bilaspur
West Bengal SCTH, Malda
All North-Eastern States RDO, Guwahati
Jammu & Kashmir, Himachal Pradesh, Punjab , Haryana, Chandigarh TTL, Srinagar
Northern Karnataka , Western Maharastra , Marathwada DCTSC, Dharwad
How a beneficiary is selected?

A beneficiary is selected based on his experience, availability of infrastructure, site inspection and recommendation by the CSB Zonal team. On selection the CSB Zonal officers in writing shall inform the beneficiary.
When the beneficiary has to place the purchase order to the manufacturer?

Only after the receipt of the approval letter from the Zonal office of CSTRI, CSB informing the beneficiary about his selection for the scheme, the beneficiary should send the purchase order to the manufacturer of his choice.
Can I switch over from one package to another?

No. Switching over can be effected only with the consent of CSB Zonal office.
When is the subsidy released?

The subsidy is released only after the erection and commissioning of all equipments and after the receipt of the satisfactory working performance certificate from Zonal office and beneficiary.
Do I have to produce any documents along with application?

Yes. The following documents are to be submitted along with the application.
a) Duly signed photograph pasted in the appropriate space on the application.
b) Copy of the Electricity Bill or Copy of the application requesting for required power.
c) Copy of Building plan
d) Copy of land registration document (or) lease agreement.
e) Any proof to establish his experience.
Any other documents which can establish him as an entrepreneur 
Who shall place the order?

On receipt of a selection letter, the entrepreneur himself has to place the order to the manufacturers. An entrepreneur is free to place the order to any manufacturer of his choice with the condition that the equipments should confirm to CSB specifications. In this website, the list of manufacturers list is given for guidance only and an entrepreneur is also free to place purchase order even with the manufacturer other than those given in the website.
Who shall do the inspection?

If the order is placed with new manufacturer, the entrepreneur can request for pre-dispatch inspection so as to confirm the specification. Otherwise, the entrepreneur can request for post dispatch inspection after the machinery is erected and commissioned and in working condition. The beneficiary and CSB Zonal officials shall have to duly certify a satisfactory working performance certificate.
How subsidy is calculated and released?

On receipt of the satisfactory working performance certificate, CSB’s share shall be released to the machinery manufacturer. CSB share is calculated on the basic cost of equipments. Taxes, transportation, etc. are not covered under subsidy. If the equipment is procured at a cost lower than the indicative cost, the subsidy is calculated and released on the basis of the lower cost.
I have a working unit and I want to enhance capacity. But, I don’t want to procure entire package, is it permitted?

An existing entrepreneur is permitted to procure few equipments under package only on the basis of case by case.
Is there any working capital provided by CSB?

CSB does not provide any working capital under the XI plan schemes.