再生ABS的性能与颜色:黄变不是玄学,是丁二烯在氧化

塑料知识科普 发布时间: 2026-09-16 1941 阅读

Buying recycled ABS, what's making you nervous? It's not because the strength isn't strong enough, but because after half a year it's yellowed like an old photo, the customer returns it on the spot.

You paid a high price for 'porcelain white high-gloss material', and the injection molding turns out shiny white. After three months in the warehouse, it's already yellowed and stuffy; The impact test was just 18 kJ/m², dropped to 12 six months later, and cracked at the slightest hit in winter.

What's even more painful is that the new part tested perfectly after being made, but after two months of installation, color differences, odor, and cracking all appeared.

This article won't pile up specs, just how to use them to avoid yellowing and impact attenuation, so you have a clear plan before ordering.

The national standard bottom line for recycled ABS is: tensile strength ≥30 MPa, cantilever gap impact ≥6 kJ/m², ash content ≤5%. This is the passing line; only products that meet the threshold are considered qualified.

A better grade A material can achieve tensile strength of 38 to 42 MPa and impact of 15 to 25 kJ/m², so its performance curve is already aligned with native ABS.

But recycled material naturally has two unavoidable shortcomings: yellowing and impact attenuation. If these two are not addressed, no matter how cheap the material is, it will still leave customers with a mine.

Yellowing isn't mystical; it's the butadiene rubber in the self-igniting

ABS with double bonds. During recovery, it is repeatedly heated and oxygenated, oxidizing the bonds and forming conjugated carbonyl chromophores.

These chromophores specifically absorb blue light in the 400 to 500 nanometer band, which visibly turns yellow, with the b* value constantly rising. New material b* is usually between 3 and 5, but after half a year, it may spike above 12. Customers making white appliances are especially sensitive to b*—anything above 8 is rejected. White material turns yellow like old newspapers after half a year, which essentially means too many chromophores have accumulated.

The breakdown of brominated flame retardants produces HBr that catalyzes this reaction. Friends working with flame-retardant grade white materials should know this well: the anti-sulfur fuel turns yellow faster than ordinary materials. Quinones produced by oxidation of organotin stabilizers and antioxidants also join the crowd to deepen yellowing.

If you make white appliances and new ones look shiny when inspected, three months later the customer brings them back, shows two yellow shades, and rejects the whole batch—this isn't the customer making things difficult, but the color groups are collecting data where you can't see them.

The remedy isn't complicated: anti-yellowing agents add TiO2 to mask, then control the number of regeneration cycles. Don't let the same batch regenerate four or five times.

Impact falls off faster than stocks

butadiene phase degradation is a typical three-mode failure: rubber phase oxidation and brittleness, debonding at the interface between rubber and SAN matrix, nucleation of boundary holes, and cracks running along the holes. To use an analogy, it's like an aging rubber band—first the surface becomes brittle, then it separates from the matrix, then small voids appear everywhere at the boundary, cracks run all the way down, and impact collapses.

Quantify: It's not unusual for the first batch to lose 8% to 12% impact, but after half a year of high temperature and high humidity, impact attenuation can exceed 35%. When you buy, you test new material, but the customer uses old material from six months old. The difference is this stage of attenuation.

What's even worse is that tensile strength drops by 10% to 15%, and the Vicat softening point is shifted down by 10 degrees. In cold winter conditions, the whole batch is as brittle as soda crackers. Unmodified PCR-ABS impact retention rates are generally between 80% and 92%. If the formula is set well, it can return to the original material level; if not, it's just a matter of luck.

So for automotive or outdoor parts, don't just look at new material test reports; ask suppliers to provide aging impact retention data—that's the real performance customers will have six months later.

Cixi has a factory that makes white hair dryer casings. Previously, they used local miscellaneous materials, but new pieces turned shiny white, yellow like old newspapers after half a year, and the notch impact dropped from 16 to 9. Customers installed machines in winter cracked in bulk, with a return rate of 6%. Later, Ningbo Kelong New Materials Co., Ltd. imported PIR scraps from Vietnam and Thailand, and during the modification formula stage, they incorporated anti-yellowing and toughening systems. Six months later, the impact retention rate was still over 85%, the whiteness batch color difference ΔE remained stable below 1.0, and the return rate was reduced to 0.8%.

To put it bluntly, imported sources have controllable whiteness, stable color matching, and minimal color differences, so yellowing and impact attenuation won't cause you trouble together.

Color is the second face of recycled ABS

The color of recycled ABS is basically a pricing list.

Black accounts for the majority, has strong coverage, covers all impurities and yellowing for you, and is low-cost. Electronic appliance shells and car interiors all rely on it; White and porcelain white cost 1000 to 3000 yuan per ton more than black, and during peak seasons can even exceed 3000 yuan. To withstand yellowing, high whiteness is required, suitable for home appliance exterior parts and consumer electronics face covers; This pigment is highly clean, unstained, can be recolored, used as a high-end modified masterbatch carrier, and is priced higher than white; Mixed colored materials are positioned as low-end; for pallets, trash bins, and low-end daily necessities, a ton costs only five to six thousand.

Light-colored parts require a large amount of TiO2 to cover yellowing; one ton of material adds 30 to 80 kilograms of titanium dioxide, which alone costs over a thousand. Add screw wear and color change cleaning machines, which is why white materials cost 1,000 to 3,000 yuan.

So there's a saying in the industry: black materials can be made freely, but white materials need to be maintained. For customers doing white goods, the cost of color matching alone is much higher than for black parts. When purchasing, don't just compare material prices; the real deal is to factor in color matching and loss.

Gray is the middle route, with moderate costs, sufficient for structural and non-appearance parts; Custom colors like blue, red, and yellow require separate color combinations and remixing when changing batches. Customers with small quantities should be cautious.

Odor and VOCs determine life or death the moment of unboxing

The smell of recycled ABS is a hidden return killer.

Butadiene degrades into small aldehyde and ketone molecules, leaving residual additives and surface oil stains and sweat stains that are not cleaned thoroughly. As soon as the box opens, a strong odor is detected even in the injection molding workshop.

Especially for materials imported from overseas, if stored in the warehouse for a month, small molecules are locked inside pellets. Once the machine is turned on and the dryer is blown, all the scent is released, and the workshop odor can make people fall over.

For automotive interior parts, the odor level requirement is ≤ 3.0—if you almost refuse to accept it, the customer would refuse; For home appliance panels, the smell is even more pronounced when kept in a sealed space.

Reduce the odor level from level 5 to level 3—it's not just about spraying fragrance—first, during the extrusion stage, a vacuum devolcanization device is added to remove small aldehydes and ketones molecules, then a deodorizer neutralizes the residue, followed by deep impurity removal to remove oil stains and sweat stains. After these three steps, the odor can stay within level 3. When inspecting goods, don't just look at the appearance—opening the bag and smelling it can help you avoid half the pitfall.

Four modification directions, each pipe section

Anti-yellowing modification: Add antioxidants and UV absorbers to make white and light-colored home appliance exterior parts, with b* value fluctuating within 3 for half a year.

Toughening modification: Supplement rubber phase or add elastomer to pull the impact back to the original material level, making low-temperature outdoor parts and thin-walled shells.

Odor removal modification: Add deodorizer in the devaporation process, used for automotive interiors and low-VOC home appliance parts, with odor levels stable at level 3.

Color masterbatch: Stable whiteness, blackness, and grayscale; color difference ΔE of the same batch controlled within 1.5, no need to re-adjust colors when changing batches.

Final note: Six check mnemonics

1. Check for yellowing: test b* value on white material, don't just look at how it looks when made;

2. Check impact: test for new material once, simulate aging again, be cautious if degradation exceeds 35%;

3. Check color: black is fine for anything, white should be paired with TiO2, natural color is clean but expensive;

4. Check smell: open the bag and smell, automotive parts ≤ grade 3, home appliance parts ≤ level 4;

5. Check color difference: If the same batch ΔE exceeds 2.0, the color matching should be questioned;

6. Formula check: anti-yellowing, toughening, odor removal, color matching, choose and modify directions as needed

In conclusion: The performance and color of recycled ABS ultimately depend on the stability of butadiene and the cleanliness of the material source. Ningbo Cologne New Materials Co., Ltd. consistently addresses issues related to yellowing, impact degradation, and color stability of recycled ABS. The whiteness of imported materials is controllable, color matching is stable, and color difference is minimal—in short, it ensures that each batch of material can still be presentable even after being stored for six months.

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