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The polyamide with reduced moisture absorption

The polyamide with reduced moisture absorption


Polyamides are materials which have an extremely balanced profile of properties and can therefore be used in many industries to produce a wide range of components. However, polyamides absorb water (e.g. humidity) though diffusion. This absorption results in increased flexibility and toughness and reduced stiffness, strength and hardness. Resultant changes in volume (swelling) can lead to warpage of the component. 

AKRO-PLASTIC GmbH has successfully met the challenge of developing AKROMID® RM-M (Reduced Moisture), a blend of PA6 and PBT, which exhibits the typical, positive properties of PA6 and yet has lower water/moisture absorption rates.


With a reduction in water absorption of up to 50 % compared with standard PA6, the residual stiffness and strength of the components after conditioning is greater than with standard PA6. This enables a weight-saving construction or component design.


Product Characterisation

AKROMID® RM-M (mechanical grades) is suitable as a construction material for components subjected to high mechanical loads. This product line is offered exclusively in reinforced compounds with differing glassfibre contents in three versions: standard, surface-modified (“9”) and with increased chemical resistance (“4”). 


The AKROMID® RM-M series has significantly lower moisture absorbing compared to standard PA6. Grades with 30 % glass-fibre content absorb just as much water as a standard grade with 50 % glass-fibre content.


As a result, the tensile modulus of AKROMID® RM-M decreases significantly less over the conditioning period than that of standard PA6 and is even slightly higher than the conditioned tensile modulus of elasticity of the A3 GF 50 1 black (2387).


Resistance to Media

Of particular importance is the good chemical resistance of the AKROMID® RM-M grades against CaCl₂. CaCl2 is used, among other things, in de-icing salt to lower the freezing point.

In comparison with AKROMID® B3 GF 50 1 black (2488) and AKROMID® standard grade B3 GF 50 RM-M black (3146), AKROMID® B3 GF 50 9 RM-Mblack (3147) demonstrates a significantly improved resistance to CaCl₂. AKROMID® B3 GF 50 4 RM-M black (3221) demonstrates the highest resistance.

These ageing conditions correspond to those described in Daimler Benz test specification DBL 5416 (state: 2002).

The information regarding chemical resistance are subjective ratings based on resistance experiments according to standards DIN EN ISO 175, DIN EN ISO 11403-3, DIN EN ISO 22088. The information is intended for an initial assessment only.

Resistant Means:  
Complete resistance under specified conditions.      

Non-Resistant Means: 
Even after short-term contact, the material may exhibit some damage, in case of prolonged contact there will quickly be visible signs of chemical degradation. 

Find the Right AKROMID® RM for Your Application

A selection of polyamides for your applications.




Disclaimer: All specifications and information given on this website are based on our current knowledge and experience. A legally binding promise of certain characteristics or suitability for a concrete individual case cannot be derived from this information. The information supplied here is not intended to release processors and users from the responsibility of carrying out their own tests and inspections in each concrete individual case. AKRO®, AKROMID®, AKROLEN®, AKROLOY®, AKROTEK®, ICX®, PRECITE® and DIA(hr)LOG® are registered trademarks of AKRO-PLASTIC GmbH.

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