Plastics Scratch and Mar Resistance Advances

TAGS:  Surface Modification      Scratch & Mar Resistance    

This article was originally published in 2018 and updated in 2020.

As finished durable plastic product consumers, we like to see long lasting surface finishes free of scratches or mars that detract from the merchandise value. This requirement applies to a whole range of end-use applications that include, for example:

• Car interiors
• Electronic devices
• Appliances
• Home furnishings, and

Good product surfaces translate into good product manufacturing and quality in the mind of the consumer.

Plastics scratch resistance is multi-faceted in nature from base polymer selection, through additive technologies, to testing methods. Certain polymers like crystalline PolyPropylene (PP) scratch easily, while others like amorphous Acrylonitrile Butadiene Styrene (ABS) have hard surfaces that resist scratching.

Also, filler additives such as minerals, silicones, or nanoclays will affect scratch and mar surface visibility. The overall goal is to continually match surface appearance durability to the expected end product lifecycle.

Scratch and Mar Resistance Testing

Let’s examine what is meant technically by scratch or mar resistance since they along with the broader abrasion term are usually lumped together. When something is scratched there is surface damage in the form of a crack, a delamination, a blunt deformation, or a combination of the preceding factors, wherein a cut occurs.

A mar is more limited to a close to the surface change in gloss or color as a result of a material microcrack due to chronic internal stress and strain. The broader aspect of abrasion involves a more gradual removal of surface material with a moving contact force similar to a bearing and wear motion. These preceding failure mechanisms remain an ongoing research subject on the molecular plastics level.

In plastics surface scratch and mar testing, there have been developed many different test approaches usually tailored to a specific end-use application. Stated simply, it is hard to use just one applied test to fully characterize a plastic surface scratch or mar. So, a good approach is to correlate applied test results with fundamental failure data on an ongoing basis.

This is the best route to establish new scratch and mar testing equipment and methods. A good starting point for fundamental scratch behavior modeling can be found at Texas A&M University’s Polymer Technology Center¹.



Let’s take a look at recent plastic additive and polymer technologies that are advancing surface scratch and mar performance.

Mineral Filler Advances

Talc filled plastics will reflect light when surface scratched making the scratch more visible. Heightened scratch visibility is directly related to the mineral talc particle size. Imerys has commercialized specialty micritized ground, ultrafine JetFine^® 3C, and 3CW talcs to replace coarser industrial grade variants currently in use.

They have been found useful in automotive interior PolyPropylene (PP) parts at reduced loading levels while maintaining other key impact strength, flexural stiffness, and consistent dimensional properties.

Property	Measure	Talc (0.5µm)	Talc (2µm)	NYGLOS® 4W 10992	NYLITE™ G-10992
Five Finger Scratch 15N	FORD Grain	5	4	2	2
Erichsen Cross Cut - Test	Delta L - 10N Smooth Plaques	< 3	< 3	< 1	< 1
Erichsen Cross Cut - Test	Delta L - 10N Coarse Plaques	< 5	< 5	< 2	< 2

Ford Motor Five Finger and Erichsen Cross-Cut Automotive PP Applied Scratch Test Data

Further development by Imerys has led to optimized talc mineral filler with wollastonite fiber mechanical blends that possess low odor characteristics for automotive interior surface applications such as consoles and door panels while maintaining good mechanical properties. Imerys has developed new NYGLOS^® and Nylite wollastonite talc blends that minimize the surface scratch appearance.



View Several Talc Filler Grades Suitable for a Wide Range of Polymers »

Additives to Improve Plastics SMR in Automotive

BASF’s proprietary additive Irgasurf® SR 100 B has a typical usage level of 1-3%, and provides excellent scratch and mar resistance (SMR).

• Like silicone and slip additives, it lubricates the surface reducing scratch visibility.
• Unlike erucamide-derived additives, Irgasurf® SR 100 B does not migrate and does not cause problems with surface tackiness or poor paintability.

Irgasurf® SR 100 B improves scratch resistance in PP homopolymer, PP copolymer, TPO/TPEs, TPV, ABS, ASA, SAN, PC/ABS, PS, HIPS and PVC, and works in both filled and unfilled systems.



TEGOMER® AntiScratch 100 additive for TPO auto interiors from Evonik is based on organic-modified siloxane. It provides permanent scratch resistance with no fogging or gloss change.



Axel Plastics Research Laboratories’ MoldWiz® INT-35 CPD is a new additive designed to improve SMR in TPO for automotive applications.

• The additive is a proprietary synergistic blend of modified polymers and organic fatty amides. It has no fogging, odor, or interaction with UV stabilizers.
• The additive also reduces resin viscosity in extrusion and injection molding increasing productivity.

Access More Anti-scratch & Mar Resistance Additive Options »

Nanotechnology Choices

Another key advance has been Australian TenasiTech’s nanoclay SOLID-TT scratch and mar resistant additive development. Their patented nanoclay additive advance has worked best when compounded into highly polar plastics like:

• Nylon
• Acrylic
• Polycarbonate, and
• Thermoplastic urethanes

SOLID-TT is non-surface migratory in nature and exhibits excellent dispersion throughout a given polymer structure. Furthermore, nanoclay platelet sizes and surface treatments are tailored to a given polymer system to further enhance dispersion within the given polymer.

In this way, the bulk polymer is fully reinforced and its surface strengthened, which in turn leads to increased scratch and mar resistance. TenasiTech’s nanoclay SOLID-TT approach finds its best use in unfilled polymers where avoiding the use of hard coatings is desirable.

Hard coating plastic surfaces is always an expensive secondary process; using high-cost UV (Ultraviolet) cured siloxane materials. End-use market high gloss applications in automotive interior surfaces, cell phone back panels, and appliance housing are growing rapidly at present and can no longer tolerate higher cost, secondary processed hard coatings.

TenasiTech has done extensive applied pencil hardness scratch testing, finding, for example, that their SOLID TT additive has increased from lower 3 to 4H levels to current 7-8H levels at 1% loadings by weight. Similarly, in very scratch prone, uncoated polycarbonates, pencil scratch tests results have improved from standard, unsatisfactory 2B to 1-2H levels.



Let’s now discuss silicone additive used in scratch and mar resistance.

Silicone Additives

The use of silicone alternatives started a decade and a half back when mineral talc filled PolyPropylene (PP) was heavily penetrating automotive interior applications, like:

• Glove box covers
• Lower dashboard/door panel surfaces, and
• Trim edges

These types of surfaces are matte, nonglossy in nature to minimize blinding light reflection in the driver’s eye. Matte surfaces are easily prone to scratches and mars - just envision a shoe scuff scratching a lower door panel edge when getting into a vehicle. Talc filled plastics accentuate this scratch/mar effect. High molecular weight silicone additives, when added to cost-efficient talc-filled PP that are encapsulated in the PP polymer structure, will produce a low friction surface that in turn reduces visible scratches and mars.

Wacker's Silicones Genioplast® Pellet S

A notable scratch resistant additive is Wacker Silicones Genioplast® Pellet S specifically developed for automotive. Genioplast Pellet S’ silica-based carrier allows it to be compounded with any mineral filled thermoplastic without sacrifice to existing mechanical, UV (Ultraviolet), flame retarded, non-tacky surface, or anti-fogging properties.

Dow's Performance Silicones

Dow Performance Silicones also have high molecular weight anti-scratch silicone additives namely, HMB-0221 for PolyPropylene (PP) and HMB-1103 for acetal (PolyOxyMethylene, POM). These additive systems have a long history in use are:

• High molecular weight masterbatches
• Cost-reducing in compound processing, and
• Typically formulation added at 0.5 to 2.5% by weight

Evonik's TEGOMER® M-Si 2650

Evonik also offers their Tegomer® AntiScratch 100 modified silicone additive aimed at longer-term consumer durable uses such as:

• Large appliance (washing machine, dryer), and
• Small appliance (kitchen dishwasher, compactor) control panel surfaces

There is ongoing and accelerating trend to polypropylene where better scratch and mar resistance on glossy surfaces is required over ten to a fifteen-year product in use life cycles. Additionally, Evonik has also commercialized a Tegomer® M-Si 2650 silicone additive grade for use with ThermoPlastic Elastomers (TPE) for automotive end-uses.

Polymer Options

Raw material suppliers have also taken an interest in improving scratch/mar surface properties to minimize or remove the need for compounded additives or finish coatings in plastics parts.

Let's take a look at some noteworthy examples:

BASF’s Ultramid® Deep Gloss Specialty Nylon for Automotive Interiors

This crystalline, chemically resistant nylon 66 has an amorphous high gloss look combined with a nylon 6 ease of processing. This plastic is initially aimed at high touch automotive interior applications where chemical and UV (Ultraviolet) resistance is required such as:

• Decorative trim
• Light frames
• Door/center console/air vent inlays, and
• Headliner storage racks

They are replacing painted Acrylonitrile Butadiene Styrene (ABS) parts. Ultramid® Deep Gloss has not only a piano black depth of color look but is also similarly available in porcelain white, ivory and earth tone brown hues for consumer durable good products.

Hyosung's Poketone™ Polyketone

South Korean resin supplier Hyosung has commercialized over the last five years its high temperature resistant, hard surfaced, naturally scratch/mar resistant, Poketone™ aliphatic polyketone. These additives have comparable stiffness, higher impact strength, and elongation to break compared to acetal (PolyOxyMethylene (POM)) engineering plastic, along with twice the surface wear resistance.

In addition, Hyosung with its improved polyketone grade has performed noise and vibration testing at different RPMs (Revolutions Per Minute) versus acetal and found lower noise deciBel (50-60 dB) levels as a result of the resin’s inherent damping properties.

Anti-scratch Agents for a Wide Range of Polymers

View several commercial grades of anti-scratch additives available today, analyze technical data of each product, get technical assistance or request samples.