Plasticizer

(Softening-, Plasticizing-, Elasticity Agent )

Terminology for liquid or solid, indifferent organic substances with low steam pressure. Due to their dissolving and swelling behaviour, they are able to physically interfere with highmolecular substances and create a homogenius system.

A plasticizer in aqueous paste systems with thermoplastic adhesives should provide following positive properties:

Furthermore, several requirements a plasticizer shall fulfil:

By usage of plasticizers in combination with appropriate thermoplastics (eg. copolyamide, copolyester, polyurethane, HD-PE), e-modulus and glass transition temperature are systematically lowered.

Plasticizing means the adjustment of the thermoplastic area to lower temperatures. Thermoplastics can be adjusted into the desired thermoelastic state by copolymerisation (inner plasticizing) or, that is been widely applied in practice, by adding of plasticizing agents (outer plasticizing).

By outer plasticizing the polar groups (dipoles) of the plasticizer interfere with the polar groups of the thermoplastic with frequent arranged dipoles (exception: polyolefins). Here, the small and loose plasticizerdipoles move between the chain molecules of the thermoplastic and tie up to their dipoles. The chain molecules are loosened up and become more likely to move. In some cases this can only be achieved in combination with polymer plasticizers.

In figure 1, a typical grade of sulfonamide for plasticizing of hotmelt adhesives is shown. This group of plasticizers cause a positive effect to copolyamides and thermoplastic polyurethanes.


Methyle- und Butylester of acetylized ricinoleic fatty acid are monomers for sulfonamide polymer plasticizer as for example:

hergestellt.

Figure 1 
Para-Toluenesulfonamide ( PTSA )
 

Sulfonamide plasticizer are used particularly for copolyamide adhesives to decrease the melting point (Fp°C) and melt flow index (MVR; g/10min). These primary properties are the most important parameters for the manufacturing of fusable interlinings/ substrates in paste dot coating process. Here, the melt flow index is considerably more decreased than the melting point. Thus, plasticizers are able to decrease the fusing conditions of the final product.

In paste formulations without plasticizers, the copolyamide adhesive does not change its physical/chemical properties, while by addition of sulfonamide plasticizers the desired effect of decreased fusing conditions is considerably.

The optimum input quantity of sulfonamide plasticizer in the paste formulation should be 10%-15% of the copolyamide quantity.

Example: Copolyamide with following physical/chemical properties:

Chem. basis:     Nylon 6/Nylon 6.6./Nylon 12
MVR:               25    (g/10min at 160°C)
Fp:                   125     (°C)

Figure 2 


The following figure illustrates the appropriateness of the correct plasticizer combination with commercial available copolyamides. The properties must be tested and certified prior to production. ROWAK AG will support you.




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ROWAK AG