再生AS/SAN:透明日用品的水口料,回收后透光还能剩几成

塑料知识科普 发布时间: 2026-09-14 2762 阅读

Transparent virgin material is sold by the ton, while transparent sprue material is collected by the pound. The difference is not in the material, but in the information gap. This refers to AS—also called SAN, acrylonitrile-styrene copolymer, commonly used for making transparent cups, cosmetic boxes, pen barrels, and transparent parts of home appliances. Virgin material costs over ten yuan per kilogram, but how much light transmission can remain when transparent sprue material is recycled and granulated from injection molding? This article clears up the accounting for recycled AS.

Let's spend two minutes getting to know the main character. Ningbo Kolon New Materials Co., Ltd. has long dealt with AS raw materials, with recycled AS being one segment. AS is a transparent resin copolymer of styrene and acrylonitrile—clear, rigid, and chemically resistant, with an appearance that is watery white and slightly translucent. It is slightly harder than GPPS, chemically more resistant, and more transparent than ABS without whitening, specifically used for parts that require transparency along with a certain rigidity. Transparent water cups, cosmetic boxes, lotion bottles, pen barrels, transparent storage boxes, and transparent decorative strips on home appliances are all its domain. The sources of recycled AS mainly come from two aspects: injection-molded sprues and defective products from transparent daily necessities factories, and scraps from pen barrel and cosmetic box factories.

Transparent materials are sold by the ton, water outlets are charged by the pound, the difference is an information gap.

Factories doing AS injection molding all have a common experience: for transparent water cups or cosmetic cases, one mold can produce a dozen or so pieces, and a large chunk of transparent sprue material comes out along with them. This sprue material, just out of the mold, is clear and transparent, a single grade, with the same composition as the final product. In knowledgeable factories, the sprue material is casually crushed and mixed back into the machine in proportion; in less experienced ones, the transparent sprue material is mixed with other pigments and sold cheaply, just a few yuan per kilogram—such a waste.

Transparent materials are different from other materials; most of their value lies in their 'transparency' and 'color.' As long as transparent sprue material is not mixed with other colors or yellowed, its light transmittance can still remain at a high level after being recycled into pellets. Once it is mixed with other colors or yellowed after repeated recycling, it drops from high-grade transparent material to low-grade opaque material, cutting its value in half. Therefore, the first step in recycling AS sprues is to separate the transparent, natural-color material.

Why is the hue of transparent materials so precious? Because customers who make cosmetic containers and transparent cups are very particular about color and light transmission. For the same cup, whether it's crystal clear or slightly yellowed, the visual appeal on the shelf can differ significantly, and the price will differ as well. Recycled AS, as long as the hue is stable, looks no different to customers compared to new material, yet the price is cheaper, which is its market space. Conversely, if the hue is off, even the best material can only be used for low-end products.

Let me put it more clearly. In the transparent daily necessities business, material costs make up a significant portion, but customers are sensitive to price, so the selling price can't be raised. By mixing back clean transparent sprues, the material cost drops significantly, the cup's selling price stays the same, and the profit comes. This isn't cutting corners; it's using the materials that should have been used in the first place— as long as the color and transparency are maintained, customers can't tell at all. This is smart cost reduction, and factories that make transparent daily necessities should make this calculation clear, so good materials aren't wasted in mixed piles or sold cheaply.

When transparent material turns yellow, the price drops by half — stable color is more valuable than a lower price.

Figure 1 Recycled AS/SAN Transparent Pellets and Transparent Products (Schematic Diagram)

Recycling AS transparent materials, maintaining translucency and color hue is key

If we look at recycled AS in terms of light transmittance and usage, it can roughly be summarized in the table below (the indicators are a general range commonly used in the industry, and specifics should follow the manufacturer's TDS). For AS, light transmittance and color tone are crucial indicators: high transmittance and water-white color can be used for transparent appearance parts; yellowed or darkened material can only be used for translucent or opaque parts.

LevelTypical sourceKey indicatorsTypical Applications
Water-clear transparent recycled ASClean transparent sprues, defective productsHigh light transmittance, correct huetransparent cup, cosmetic box
Light Blue Transparent Recycled ASEdges and corners of transparent productsGood light transmission, slightly bluishTransparent stationery, storage boxes
Natural Regeneration ASNatural-colored sprue materialMedium translucencyGeneral transparent part
Light-colored Recycled ASLight-colored sprue, slightly yellowTranslucent, average hueNon-appearance transparent parts
Black Regeneration ASVariegated nozzle, mixedOpaque, cheapStructural components, modified base material
Filling Regeneration ASFilling-level sprueStable size, not permeableOrdinary structural components

Market reference: Recently, clean and transparent recycled AS granules are a notch cheaper than brand-new transparent grade, while yellowed and black grades are even cheaper. When Ningbo Kolon New Materials Co., Ltd. quotes AS material, they usually first ask whether downstream customers are making transparent appearance parts or ordinary parts and how high the transparency requirement is, then they determine the grade based on color tone and transparency—because in the AS industry, if you ask the wrong color tone, you won't be able to make a clear cup with cheap material.

Let me say a bit more about the process of recycling AS. When recycling and pelletizing AS transparent material, the temperature cannot be too high; if it is, the material will yellow and its light transmittance will decrease. So during pelletizing, the temperature should be tightly controlled, and the filter screen should be changed frequently to prevent impurities from mixing in. Transparent material is most sensitive to black spots and yellowing—a tiny impurity on a transparent part is an obvious spot, which can immediately cause the part to be rejected. Experienced recycling plants wash and pelletize transparent sprues separately, without mixing them with colored materials.

There's a number for light transmittance: brand new general AS has a light transmittance of about 87% to 90%, with very low haze. Mixing back material from a single clean sprue results in limited loss of transmittance; material recycled multiple times gradually shifts in color towards yellow, and transmittance decreases accordingly. For making transparent appearance parts, prioritize using material from a single clean sprue; for non-appearance parts, only then dare to use material recycled multiple times.

Along the way, distinguish between AS and the several other transparent materials nearby. GPPS (general-purpose polystyrene) is more brittle and cheaper; AS is harder than GPPS, more chemically resistant, and slightly more heat-resistant; ABS is opaque and toughened with added rubber. When recycling, don't mix AS with GPPS or ABS—if GPPS gets mixed in, the material becomes brittle; if ABS gets mixed in, the material turns white and opaque; transparent parts are scrapped immediately. Experienced recycling plants will store and pellet these different transparent materials separately.

Let me talk about something related to processing. For AS transparent material injection molding, both the mold temperature and the material temperature need to be properly controlled. If the material temperature is too high, it will yellow; if the mold temperature is too low, the surface will become foggy. Recycled material, because it has already been through a heat history, has a slightly narrower processing window than new material, so the temperature parameters need to be adjusted accordingly. Experienced factories processing recycled AS will first run a few trial molds on a new machine to get the material and mold temperatures right before starting mass production, rather than just using the parameters for new material directly.

There are also special considerations for storing transparent materials. Recycled AS pellets will develop silver streaks during injection molding if they absorb moisture, which will ruin the appearance of the parts. Therefore, the finished pellets should be stored in sealed containers and dried before being used, rather than being piled openly in the workshop. It may seem like a small matter, but factories that make transparent appearance parts all know—if a batch of material gets damp, the entire mold of cups can end up with silver streaks, causing significant loss.

Let me mention another new thing in the industry. Nowadays, some recycling plants produce recycled AS with GRS certification, achieving a recycled content of over 30%, which is suitable for export orders and brand customers that require a certain recycled content. The source of this material is traceable, and the batches are stable, with prices higher than ordinary water-gate recycled material. For general domestic products, ordinary water-gate recycled material is sufficient; if you want to produce export brand orders, consider using GRS-certified material.

The accounts of recycled AS save money at the water inlet, but the value lies in consistent appearance.

When accounting for recycled AS, you can't just compare the price per kilogram of the material. Take the material price, light transmittance, hue, and yield rate together and lay them out:

Cost itemBrand New ASRegenerated ASDifference Explanation
Raw material purchase priceBenchmark pricea bit lowerThe spread for transparent grade is narrow, while the spread for black grade is wide.
Light transmittanceTallThe clean water inlet is close to the new materialThe transparency decreases with more recycled material
HueWater WhiteA water inlet is relatively stableThe material is often yellowish.
Appearance of black spotsNoneDepends on cleaning the filter screenRejected based on appearance due to many impurities
Rigid and chemical-resistantGoodBasically preservedRepeatedly blending and slightly reducing
Full-year comprehensivesuperficially expensiveCost-saving for transparent partsVerify high-gloss exterior parts first

If you thoroughly study this table, you'll find that the real cost-effectiveness of recycled AS is not in confronting high-gloss perfume bottles, but in mastering items like transparent cups, cosmetic inner boxes, and stationery—those 'sensitive to color but not extremely picky.' As long as these items are clear and white without yellowing or black spots, recycled material looks no different from new material to customers, yet costs significantly less. On the other hand, high-gloss perfume bottles and high-transparency optical parts become appearance disasters if the color turns yellow, so don't gamble on saving material costs.

I'll say a few more words about the market. The price of recycled AS follows that of new AS and styrene; when new material rises, transparent runner material also becomes sought after. For factories making transparent daily necessities, having a stable source of transparent runner material and managing it separately is like having an extra transparent material warehouse ready for use. The key is not to mix natural transparent material with colored material—once mixed, the entire batch of transparent material is downgraded.

Let me give a practical example. When sourcing recycled AS externally, don't just look at the price—first check what type of product the material comes from. Pen barrels and transparent water cup gates have a uniform grade and stable color; externally sourced mixed transparent materials may contain a mix of GPPS and ABS, resulting in cups that are cloudy and brittle. Using our factory's transparent gates as the main material and supplementing with externally sourced material is a more stable combination. For externally sourced material, first compare the color against light, then test it on the machine, and only increase the quantity if it passes the appearance check.

Which transparent parts can directly use recycled material, and which ones still need to be watched—let's make a clear list:

Safe to use: transparent water cups, cosmetic boxes, stationery, storage boxes, transparent parts of home appliances.

Use with caution: for high-gloss exterior parts, select clean single-gate pieces, and check the color and black spots.

First verify: for repeatedly recycled material, check the light transmittance and yellowing before moving to batch production.

Do not touch: Long-term outdoor weather-resistant parts, high-impact parts, and food-contact parts must first pass compliance.

Purchasing actions: check the light transmittance, check the hue, check for black spots, don't just ask how much it costs per kilogram.

The comings and goings of a basket of transparent watergate material: from pen barrels to cosmetic boxes

Let me give an example of a scenario that any manufacturer making transparent parts would recognize (just an example, don’t try to figure out which company it is). There’s a factory in Ningbo that makes transparent daily-use items. They used to supply brand-new transparent AS injection-molded water cups and cosmetic boxes. The leftover transparent sprue material was mixed with other colors and sold cheaply, while the new material was expensive. The boss always felt that transparent parts had thin profit margins.

Later, they connected the two ends: they separately picked out the transparent natural sprue material from the workshop, cleaned it, dried it, and granulated it on its own, turning it into water-clear recycled AS pellets, which were then mixed back into the machines producing transparent cups in proportion. Ningbo Kelong New Materials Co., Ltd. helped streamline this process—keeping the granulation temperature within a non-yellowing range, regularly changing the screens, starting the mixing ratio from a small amount, and increasing it only after measuring transparency and appearance. After smoothing the process, the amount of newly purchased material decreased significantly, the sprue material was no longer sold cheaply, and the cups maintained a clear appearance.

They also ran into problems. The first time, they crushed the transparent granules together with other colorants, and the resulting cups turned slightly yellow, with the client picking out quite a few defective ones. Later, they separated the transparent granules and granulated them on their own, lowering the granulation temperature a bit, and the yellowing disappeared. This case shows that saving money on materials with AS recycling is possible, but only if you don’t cut corners on sorting and color control.

After calculating it down: after mixing back the transparent sprue material, the cost per ton of material dropped significantly, and the customer, seeing no defects in appearance, found it usable. What this order illustrates is not complicated: the profit from AS recycling lies in separately accounting for the transparent natural color sprue. Ningbo Kolon New Material Co., Ltd. provides AS recycling supply, not by selling a bag of pellets, but by helping downstream processes smoothly handle sorting, color control, and blending.

When selecting recycled AS, first ask about light transmittance, then ask about hue.

A few commonly used destinations, condensed into a comparison table, select the level according to the category:

Application scenarioRecommendation LevelPrecautionsWhen to stop using
Transparent water cup, tablewareWater-clear transparent recycled ASTransparent packaging and food complianceLong-term outdoor pre-validation
Cosmetic boxes, lotion bottlesWater white / slightly blue transparent ASLook at the color and black spotsHigh-end perfume bottles first need verification
Stationery, pen barrelNatural Regeneration ASCheck appearance consistencyHigh-gloss exterior parts should be handled with care
Transparent storage boxNatural color/light color regenerated ASPrice PriorityDo not use high transparency parts
Transparent decorative strip for home appliancesLight Blue Transparent Recycled ASCheck weather resistance and hueDo not use for long-term outdoor purposes

Let me mention another common misconception. Some people shake their heads when they hear 'recycled transparent material,' thinking its light transmittance definitely won't be good. In fact, if you thoroughly mix in sprues once, the transmittance isn’t much different from new material, and it’s perfectly fine for making transparent water cups. The real pitfalls don’t lie in 'recycled' material, but in mixing transparent base material with colored scraps, overheating during granulation causing yellowing, or not changing the filter leading to black spots. Pay attention to these three points, and recycled AS becomes an affordable material readily available for manufacturers of transparent daily-use items.

Let me talk about something related to orders. Nowadays, many brand clients are starting to require suppliers to include a certain amount of recycled content. This is both an environmental pressure and a brand selling point. If you run the chain for mixing recycled content into your factory’s clear resin in advance, it’s like having an extra card to handle this kind of order. Waiting until the client makes a request to find materials is often too late; regularly managing the clear resin stock means you can supply stable batches directly when needed.

How much recycled AS is appropriate to mix with new material? For making transparent water cups or ordinary cosmetic boxes, the mixing ratio can be higher; for high-gloss perfume bottles and high-end packaging, start with a small amount and increase it batch by batch while matching the color. Don't go in with a high ratio right away — transparent materials will yellow slightly if recycled material is mixed multiple times, and if you add too much, customers can spot it when looking against the light. The mixing ratio also depends on your colorants and molds; directly copying the ratio from another factory will most likely require rework.

Purchasing recycled AS, here's another practical tip: For the first collaboration, start with a sample. Check the color under light, count the black spots, measure the light transmittance, and make a few cups on the machine to see the appearance. Only if it passes inspection should you discuss bulk orders. The trick with transparent material isn't in a single batch, but in whether the color drifts between batches — this batch may be water-white, the next batch could turn yellow. Write the acceptance criteria into the contract in advance and attach color matching data for each batch; that's more reliable than just saying it verbally.

Let's make this clear: recycled AS is not some advanced technology; what it earns is money from 'pure transparent materials without mixing.' Even if new material is very clear, it's a waste if transparent sprues are piled in the corner and mixed with color. By separating them and controlling the color, the cost of transparent daily-use products can be reduced by a unit. When it comes to transparent materials, ultimately it's about light transmission and hue. If you maintain these two, recycled material can be used just as well. This is how the accounts for transparent daily-use products are calculated: whoever acts first benefits. This is the trick of the trade; insiders understand, while outsiders are still paying their dues. This is the difference, and also where the opportunity lies. If handled properly, there is real, tangible reward, rest assured.

When it comes to transparent materials, what you're ultimately striving for isn't cheapness, but that hint of water-white color that doesn't yellow.

The regenerated AS has stable color hue, making the transparent parts clear and bright.

Disclaimer: The brands and trademarks mentioned in this article belong to their respective original manufacturers. This article is a third-party material selection knowledge sharing. The specific grades, parameters, prices, certifications, and other information involved in the text are subject to the latest official data from each manufacturer. This article does not constitute any procurement or investment advice.

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