SPECIFICATIONS:

PROPERTIES & USES:

1. AVCO-ZIM UND is a bacterial alpha-amylase with a high enzymatic activity.

2. Optimum activity is in the temperature range of 40-80º and pH range of 7-8.8. In lower temperatures longer treatment time is needed.

3. The strong amylolytic action of AVCO-ZIM UND allows rapid conversion of the starch size into dextrin, which is easily removed by hot washing-off process.

4. AVCO-ZIM UND has high stability to soiling and impurities such as fats, waxes and lubricants which may occur in the desizing bath

5. AVCO-ZIM UND is suitable for high liquor ratio batch machines such as jet, jiggers and rotary washing machines.

6. AVCO-ZIM UND is recommended for application in continuous pad steam method, and for the semi-continuous pad batch method.

7. AVCO-ZIM UND can be used together with slightly acidic complexing agents to obtain one step demineralization and desizing process.

8. Salts and calcium addition to the desizing bath is not needed.

9. AVCO-ZIM UND is an excellent desizing enzyme for removing starch from denim garments before the “Stone-washing” process.

APPLICATION:

1. The quantities and treatment time depend on the type of fabric and the desizing method.

General suggestions

a. For batch treatments (high L.R.) use: 0.5 – 3.0 g/l

b. For jig (low L.R.) use: 2.0 – 4.0 g/l

c. For pad-roll treatment use: 2.0 – 4.0 g/l

d. For pad batch use: 2.0 – 6.0 g/l

1. The pH of the desizing solution must be 7-8.8.

2. The treatment temperature should be 40-80°C.

3. The treatment time recommendation is for high liquor ratio methods 45-90 minutes and for continuous (pad roll) 4-8 h dwell time.

4. Add 0.5 g/l de-aerating agent such as AVCO-TEX CAN.

6. Usually continuous desizing is linked to singing machine and the speed of the singing reaches up to 150 m/min. At the stage of desizing it is needed to remove all additives incorporated in the sizing such as waxes, paraffin’s and all soiling and staining on the fabric that may have been accumulated during weaving. It is therefore important to add an emulsifying and a dispersing agent with high wetting power and compatibility with enzymes. Such products are AVCO-PAL SFN, AVCO-BIOPAL LFB and AVCO-BIOLIT 2090.

7. The solubilized size must be washed out before the cloth is transferred for bleaching and dyeing. The best results are achieved by alkaline boiling (3-5 cc/l caustic soda -50%). The addition of AVCO-POLYQUEST PDK (1-2 g/l) will help eliminate water hardness and other metal precipitates from the fabric.

TYPICAL DESIZING PROCEDURES 1. Jigger

AVCO-TEX CAN 0.5 g/l

AVCO-PAL SFN 1.0 – 3.0 g/l

AVCO-ZIM UND 2.0 – 4.0 g/l

Adjust pH to 7 – 8

Run 4-6 ends at 60-90°C.

Remove degraded starch by hot washing at 95°C for 2 ends. The use of 2-4 cc/l of caustic soda (50%) and 1-2 g/l of AVCO-POLYQUEST PDK will improve the results.

Neutralize and rinse well.

2. Pad roll batching-up method

AVCO-TEX CAN 0.5 g/l

AVCO-BIOLIT 2090 3.0 – 6.0 g/l

AVCO-ZIM UND 4.0 – 8.0 g/l

AVCO-TRYL HPH 0.5 – 2.0 g/l

Adjust pH to 7 – 8.8

Pad at 20-90°C, wrap with a plastic foil and store in a rotating rolling station for 4-24 hours.

Remove degraded starch by hot washing at 95°C. The use of 2-4 cc/l of caustic soda (50%) will improve the results.

Neutralize and rinse well.

3. Desizing of Denim garments (Rotary Washers)

AVCO-SLIP RF 1.0 – 3.0 g/l

AVCO-BIOPAL LFB 1.0 – 2.0 g/l

AVCO-POLYQUEST RE 0.5 – 1.0 g/l

AVCO-ZIM UND 1.0 – 3.0 g/l

Treat at 50-65°C for 15-30 minutes, followed by hot and cold rinse.

4. Pad steam enzymatic desizing

AVCO-TEX CAN 0.2 – 0.5 g/l

AVCO-BIOLIT 2090 3.0 – 5.0 g/l

AVCO-TRYL HPH 1.0 – 3.0 g/l

AVCO-ZIM UND 3.0 – 6.0 g/l

Padding at 20-90°C followed by steaming for 1-30 minutes under saturated steam conditions.

Wash with hot water at 95°C. The use of 2-4 cc/l of caustic soda (50%) will improve results.

TESTING FABRICS FOR THEIR DEGREE OF DESIZING

Preparation of iodine solution:

Dissolve 10 g of Potassium Iodide (KI) in 100 ml. of water, add 0.635 g of Iodine and shake well. Top up with water to 800 ml and finally add Ethanol to reach 1 liter.

According to the TEGEWA – Violet scale for assessing the desizing degree of starch, immerse a de-sized fabric sample (which is pre-rinsed in hot alkaline and cold water) in the Iodine solution for a period of about 1 min. After immersion rinse shortly in water, damp with filter paper and compare immediately with the violet scale.

Judge according to the following results:

1. Pure dark blue coloration c presence of non-degraded starch.

2. Pale blue coloration c slight starch residue onto the fibre.

3. Red-violet coloration c starch degraded into water-soluble dextrin.

4. Yellow coloration c completely free from starch.

Degradation into a reddish-violet colour is adequate for solid shades.