Title:

To apply the effect of different concentrations of resin on 100% cotton fabric and characterize the properties of finished fabric.

1         Abstract:

The purpose of this experiment was to compared the Effect of Various Concentrations of on 100% Cotton Fabric. In this experiment, we studied the crease recovery angle and tear strength of the given piece of sample. The resin used in this experiment is Fixapret CPF in the presence of Condonsol FM which is MgCl2 in purified form is used as a catalyst in resin finishing for acid medium. Different concentrations (30g/l,60g/l,90g/l,120g/l) of resin were applied on fabric to check the effect of resin on different mechanical properties of fabric. Fabric was dried at 120 °C for 2 minutes and cured at 150-160 °C for 1-2 minutes. Then all samples were tested. Tear strength was tested by Elmendorf’s Tearing tester. Crease recover of fabric was examined at Crease Recovery Tester.

2         Introduction:

Resin finishing is a process of bringing out a special property of “CREASE RECOVERY” to cotton. Resin are cross linking agents which form covalent bond on reaction with OH group of cellulosic groups in acidic medium at a PH of 3-4[1]. The main objective of resin finish is to keep the fabric surface flat and smooth and free from undesirable creases.  Resin finish also known by some other name such as:

·         Wash and wear finish

·         Anti-crease finish

·         Crease resistant finish

·         Durable press finish

·         Wrinkle free finish[2]

Resin finish are of two types:

1.      Deposition type of resin (not react with the fabric surface)

·         Phenol formaldehyde resin

·         Urea formaldehyde resin

·         Vinyl resin

2.      Crosslinking type of resin

·         DMU (di methylol urea)

·         DMEU (di methylol ethylene urea)

·         DMEHEU (di methylol di hydroxy ethylene urea)

·         DMPU (di metylol propylene urea)

Resin a chemical based finish that is applied on the fabric to increase the crease recovery of fabric. It is a special property that is mostly impart in cotton fabric. It is also called Crease Recovery, Wash & wear, Anti Crease finish, Crease resistant finish, Durable press finish and wrinkle free finish etc[3].

Crease or wrinkle is one of important issue in cotton fabric. Everyone knows cotton is hydrophilic fabric. Its polymer is cellulose that contains large amount of hydroxyl group. Shown in Fig. 1. These hydroxyl groups are responsible for hydrogen bonding. When the fabric is folded the previous hydrogen, bonding is destroyed and new bonding formed. New bonding is stronger than previous so the fabric can’t move back to previous shape.

Fig. 1.  Cellulose monomer

This issue can be lower down by applying the resin on cotton fabric. Resin is a cross linker so it penetrates in the amorphous of the cellulose. Resin reacts with hydroxyl group of cellulose and form a new covalent bond. So hydrogen bonding is reducer and covalent bond is formed which is more stable than hydrogen bonding.

 

There are two types of resins.

Formaldehyde based resins:

·         Urea formaldehyde

·         Melamine formaldehyde

·         Dimethyloldihydroxyethylene urea resins (DMDHEU)

Non-formaldehyde resins:

·         Dimethyldihydroxyethylene urea. (DMeDHEU)

·         1,2,3,4-Butanetetracarboxylic acid (BTCA)

The catalyst used for resin containing low formaldehyde is condonsol FM. As the cross-linking take place in acidic condition so catalyst provides acidic condition for cross-linking[4].

 

3         Materials and Method:

3.1        Materials:

100% bleached cotton fabric is engaged for to perform this experiment whose fabric quality is 40*40/110*90 and fabric structure is plain weave and also the GSM of the fabric is 128 g/m2. Resin Fixapret CPF manufactured by BASF Pakistan Pvt Ltd. Catalyst (Condonsol FM)

3.2        Method:

Firstly, the pickup percentage of the given fabric is calculated by dipping it into the distilled water and then passing it on the padder. The pickup of the given fabric is 93%. After that the amount of the 3% resin used for the 300ml solution is calculated on the weight of the fabric by following formula.

3.3        Recipe

§  water   1000 ml                                  

§  PH       5.5-6                                       

§  Drying temperature     120 degree (2 min)

§  Curing temperature     150-160 degree (1min)

§  Resin   3%

Resin   =  90g/l                       

MgCl4  = ¼ of resin

4         Procedure:

As calculated by the above formula the 9.67g Resin and 290g of the water is stirred in a beaker. And also maintained the pH of the solution present in the beaker at 6. Moving onto recipe setup, we went to the padder machine by adjusting padder pressure at 2bar we passed the fabric through the padder uniformly after that the given fabric was dried at 120oC for 2 minutes with the help of Stenter machine. The fabric was then again passed through Stenter set at 150-160ºC for 1-2 minutes to cure it.

5         Characterization:

5.1        Crease Recovery:

Specimen for crease recovery test was “1*2” size. Warp side was 2” long for warp crease recovery test and similarly for weft side. Sample was fold from the half of 2” side. Folded sample was placed under 500g weight for 1 minute. After 1-minute sample was let free to recover for 1 minute. Then one side of sample was put in plates of crease recovery tester. Other side of the sample was straight to below point and angle in front of needle was noted. Angle for both warp and weft was noted. Three, three specimens of warp and weft were examined[5].

5.2        Tear strength:

The tear strength of fabric was checked by ELMENDORF’S TEARING TESTER. Fabric was cut into 63.5*100 mm. Warp was 100 mm long in the sample. A cut of 20 mm was placed on one end of sample. Test was performed and reading of force required to tear the fabric was noted. Same procedure was repeated 3 times[6].

 

6         Results and discussion:

6.1        Tear Strength

Table 1 Tear strengths of cotton fabrics at different conc. of softener

 

 

Warp wise (g)

Weft wise (g)

Sample

Softener conc.

R1

R2

R3

Mean

R1

R2

R3

Mean

1

30g/l

1170

1250

1240

1220

1100

1120

1140

1120

2

60g/l

1200

1440

1480

1373

1019

1427

1223

1223

3

90g/l

1200

1200

1200

1200

800

880

720

800

4

120g/l

1040

1200

1130

1123

800

880

860

846




If we compare untreated sample and treated samples. We can observe there is a significant difference between untreated and treated sample. This is due to the less hydrogen bonding of treated sample then untreated sample. The reason behind lowering the hydrogen bonding in treated samples is cross linked with hydroxyl group of cellulose. These hydroxyl groups were responsible for hydrogen bond[8]. Cross linking of Resin lowers the number of free hydroxyl groups on cellulose so there is less resistive force in the crease recovery of cotton.

1         Conclusion

From this experiment it was concluded that as when we increased the conc. of resin the cross-linking of chain increases due to this tear strength of fabric decreased. However, the crease recovery angle increased with increase in conc. of resin because of cross-linking that don't allow the chain to form new H-bond with water molecules.