4.

The major properties of fusible interlining, such as peel bond strength, washabiltiy and aging resistance, depend mainly on the property of thermosol. The technical conditions of coating, processing and adhesion processing also depend on the thermal property of thermosal.

1.Thermosol's property requirements and its main indexes

A.Has good adhesive capacity for various fiber fabrics.
B.Has low melting temperature range and can do coating processing and pressing processing to fabric in low temperature.
C.Has proper thermal fluidity and can finish pressing processing in short time with no strike-through.
D.Has good washability, chemical reagent resistance and dry-cleanability with no obvious decline of adhesion strength after washing.
E.Has proper powdery property. The evenness and the same size of particles can meet the needs of various kinds of coating processing.
F.Has aging resistance and will not discolor under the light and in the heating condition.

The two indexes that influence the property of thermosol are melting point index and melt index.

Melting point is the temperature during the heating and melting of thermosol. Its unit is "C". The height of melting point directly influences the coating processing technique and adhesion pressing temperature. If the melting point is low, the adhesion pressing temperature will be low. If the melting point is high, the adhesion pressing temperature will be high.

Melt index is the weight value of thermosol's flow in the set time and in some temperature and pressure. Its unit is "g/10min". The height of melt index directly influences the pressure and time of adhesion pressing. The lower the melt index is, the higher the pressure is and the longer the time consumes. The higher the melt index is, the better the permeability of linings and fabric is.

2、The variety of thermosol.

The thermosol in common use has following varieties:

1, Polythene (PE): It is a kind of thermoplastic polymer which has simple chemical structure and is polymerized by ethylene. It can be divided into high-pressure low-density polythene (LDPE) and low-pressure high-density polythene according to its different production methods.

In the temperature of 200℃ and the pressure of 1500pa, the ethylene is polymerized in some speed. The produced polythene has many molecule branched chains, low crystallinity and low density （0.9-0.92g/cm3）, so it is called low-density polythene.

After eliminating air and humidity and inducting DIESELOTL, with the catalysts of triethyl and chlorinated titanium, the ethylene is polymerized in the reaction temperature of 20-70℃. And the produced polythene nearly has no branched chain with high crstallinity and high density （0.94-0.95g/cm3）, so it is called high-density polythene.

The characteristic of polythene mainly depends on the branched chain number and the molecular weight. The smaller the branched number is, the higher the density is and the stiffer the hand feel is and also the better the solvent resistance and washability is. Molecular weight decides the melt viscosity and melt flow index. If the molecular weight is high, the melt index will be high and also the welding and adhesion will be easy. HDPE melting point 125-135℃, melt index 10-20g/min；LDPE melting point 90-110℃, melt index 70-150g/min。So the adhesion temperature and pressure of high-density polythene are higher than those of low-density polythene. But it has good washability and is commonly used for shirt linings. While the low-density polythene is mostly used for non-woven linings and leather linings for its bad washability but good elasticity and hand feel. You can see the adhesion conditions of polythene fusible interlining in graph-2.

Graph-2 The adhesion conditions of polythene fusible interlining

 
2, Polyamide (PA ): polyamide has many varieties and the polyamide which is used for thermosol is the terpolymer of modified nylon 6/66/610 or the terpolymer of modified nylon 6/66/12, nylon 6/66/1010. Its characteristics are high adhesion strength, toughness, good elasticity, good wear-resistance and good dry-cleanability. Nylon 6/66/610 terpolymer thermosol's melting point is 125-135℃, its melt index is 15-18g/10min. After adhesion, it has stiff hand feel and bad washability. Nylon 6/66/12 terpolymer thermosol's melting point is 105-125℃, and its melt index can be adjusted between 15-200g/10min according to different requirements. Its characteristics are convenient adhesion, pressing and soft hand feel. The thermosol content of nylon 12 is above 60percnet. Nylon 12 can resist the washing whose water temperature is over 90℃. The property of nylon 6/66/1010 terpolymer thermosol is between above-mentioned two ones. Its melting point is 110-125℃ and its melt index is 15-25g/10min. After adhesion, it can resist the washing whose water temperature is about 40℃ and it will have soft hand feel.

 
The condition of the pressing and adhesion of PA fusible interlining: temperature 140-165℃, pressure 0.5-2kg/cm2, time 15-18sec.

 
3, Ethylene-cellulose ethylene (EVA): It is the copolymer of ethylene and cellulose ethylene. Its softness and elasticity are better than those of polythene. It has low melting point of 80-110℃ and its melt index is 70-150g/10min. It can be bonded directly by iron and has good hand feel. But it has low strength and bad washability. If the content of cellulose is above 50 percent, the wash effect can be improved. This kind of thermosol is the most suitable one for the production of non-woven linings.

The condition of the pressing and adhesion of EVA fusible interlining: temperature 115-140℃, pressure 0.5-1.5kg/cm2 , time 10-15sec

  4,polyester (PES): It is the copolymer of dihydric acid and dihydricalcohol. Good washability is its major strong point. The improved polyester thermosol has both good washability and good dry-cleanability. Its melting point is between 100-125℃ and its melt index is between 18-35g/10min. The adhesion effect will be the best when it is bonded to chemical fiber fabrics. It also has soft hand feel and good drape. It is applicable for shuttle-woven linings and knitted linings.
The condition of the pressing and adhesion of PES fusible interlining: temperature 135-160℃, pressure 1-2kg/cm 2, time 15-18sec.