Research on scratch resistance test of car interior

Research on scratch resistance of car interiors

There are several plastic products on the market surface A method of visible damage involving a scratch by a sharp object; abrasive friction wear; surface damage that alters surface properties or gloss; or \"enroll\" by a light scratch on a blunt object.

Currently, many parts in the automotive industry contain thermoplastic elastomers, such as instrument panels, bumpers (covers), windshield wipers, airbag covers, anti-scratch strips, etc., in a convenient way When using these elastomeric materials, it has been found that their scratch resistance is not very satisfactory.

According to Dr. Ashu Sharma, a senior researcher at Ciba Specialty Chemicals, yields the material under the action of compressive force and sliding force or transverse (lateral)force, resulting in ductile/brittle failure and scratches. When scratched, the uneven surface causes non-uniform light scattering and \"crab hair\".

Solutions to improve scratch performance include minimizing the roughness of the underside of the polymer and reducing the scratch shoulder to produce minimal light scattering and visibility of the scratch. Accurately measuring scratch resistance and understanding the material science behind surface damage is important to formulate improvements.

There are several test methods to detect surface damage. One is the five-finger scratch test (five-finger scratch test), which compares the visibility of scratches based on experience after scratching with different loads. US automotive OEMs often require this method.

The Erichsen cross cut test is widely used in the European automotive industry, which measures the color change ofdetects scratch voltage bleaching. The Scratch Consortium at the Polymer Technology Center at Texas A&M University (TAMU) has developed scratch testing equipment and new test methods recently approved by the American Society for Testing Materials (ASTM), Standard No. for D7027-5. The less subjectivity of the scratch test test method has been recognized by the automotive industry. As an alliance member, Ciba is actively working to link these three methods and hopes that they will be able to use all three methods in the short term.

Methods to improve scratch resistance

1. Use suitable toughening resin

In hybrid TPO, POE, EPDM, TPV (EPDM /PP) to harden PP, the addition of elastomers leads to a decrease in scratch resistance. So it is very important to choose the right elastomer, usually between scratch resistanceThe comparison is as follows: TPV>EPDM>POE.

2. Use suitable fillers

1) Talcum powder isa relatively conventional filler and it is necessary to choose a suitable coupling agent and a suitable mesh size.

2) At present, the application of wollastonite has expanded from engineering plastics to thermoplastic elastomers. Adding wollastonite can improve the temperature resistance, compression deformation and scratch resistance of thermoplastic elastomers.

3) Nanomaterials, such as white carbon black, can improve the compression denaturation, abrasion resistance and scratch resistance of elastomeric materials, but choosing an appropriate mixing process is very important.

3. Select the right additives

1) Silicon-based additives

Can use ultra-high molecular weight siloxane polymers produced by Dow Corning and Wacker or its masterbatch, silicon-based additives produced by Sichuan Chenguang in China have also been widely used. Siloxanes migrate because of theirhigh molecular weight does not reach the surface, resulting in very good, long-lasting scratch resistance.

2) Fluoro Additive (PPA)

At present, DuPont (DuPont) and 3M have fully fledged fluorine additives on the market.Improve the fluidity of polymer melting and mold release , accelerate the extrusion speed, and most importantly, it can improve the scratch resistance and wear resistance.

3) Slippery Agent

Like Croda\'s oleic acid amide ER and erucic acid amide VRX, when added to thermoplastics, they will migrate to the polymer. The surface of the product, or bloom, creates a waxy layer that reduces the coefficient of friction and reduces the visibility of scratches. The downside is that it is not really \"dry\" and cannot fully improve surface tack.

4) New non-migratory surface agent

Ciba developed a unique anti-scratch additive Ciba IRGASURF SR 100 in 2005, which improves the scratch resistanceid of materials can be greatly improved by adding only a small amount of anti-scratch properties. This high-quality additive can be used in bumpers, dashboards, door panels and more.

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