再生PI/PSU/PEI:半导体工装边角料,特种料回收的小众生意

塑料知识科普 发布时间: 2026-09-12 1005 阅读

PI, PSU, PEI—saying their names sounds like a tongue twister. Anyone who works with high-temperature components knows that these three are tough nuts. Each one withstands higher temperatures than the last, each one is more expensive than the last, and each one is more precious than the last—but when it comes to cutting costs, nine out of ten factories dare not touch their recycled materials, fearing that performance will collapse once reused. In today’s article, we’ll break down the recycling accounts of these three 'high-temperature nobles': how much can be saved, where the savings come from, and which areas you must not skimp on.

Spend two minutes first to fully recognize these three. PI is polyimide, the 'big brother' among high-temperature resistant materials. It can withstand over 300°C for long periods and over 400°C briefly without flinching. The golden-yellow PI film (commonly called Kapton in the industry) is the go-to material for flexible circuit boards and semiconductor packaging insulation. PSU is polysulfone, transparent, chemically resistant, and can be used long-term from -100°C to 175°C. It is well-known for medical devices, water treatment membranes, and transparent chemical-resistant parts. PEI is polyetherimide, with the brand name ULTEM being the most recognized, amber-colored and semi-transparent, with a glass transition temperature of about 217°C, long-term use around 170–180°C, short-term over 200°C, tensile strength over 100 MPa, and inherently flame-retardant at V-0. It is favored for semiconductor test fixtures and electronic connectors. Ningbo Kolon New Materials Co., Ltd. supplies plastic raw materials, combining industry and trade, keeping common recycled plastics in stock year-round. Special materials like PI/PSU/PEI are small in quantity but require the most attention in quality.

The difference between these three and the common PP or ABS is that their quantities are too small and their sources too specialized. The recycled PI/PSU/PEI available on the market almost never comes from post-consumer waste; instead, it comes from clean sprues, scraps, and shavings dropped in semiconductor factories, injection molding plants, or CNC workshops—same grade, single source, free of oil, and they already know what it is before recycling. Especially for PEI, since the raw material is expensive to begin with, naturally colored shavings or injection molding sprues from the workshop are even more valuable when collected by specialized buyers. If mixed with other plastics or contaminated with oil, its value immediately drops by half. When Ningbo Kolon New Materials Co., Ltd. collects this type of material, they target clean scraps within the factory and do not accept miscellaneous colored materials of unclear origin.

Specialty material recycling is a small business, and what it earns is the word 'clean'.

Don't underestimate this pile of scrap material. The price of one ton of new PEI is enough to buy dozens of tons of ordinary PP; PI films, PI sheets, and rods are even priced by the gram. In a year, semiconductor factories and precision machining shops can accumulate quite a bit of money just from the natural-colored shavings milled in the workshop or film scraps cut off the edges. But this business has a strange phenomenon: special recycled materials in circulation outside are surprisingly scarce. Why? Because the good stuff is recycled within the factory’s own closed loop—adding a bit back to the material at one's own workstation, the quantity isn’t large but it’s enough to use, so there’s no need to release it publicly. Material that does appear on the open market is either surplus that can’t be reused internally or scrap of less clean origin. So, when looking for recycled PI/PSU/PEI on the market, don’t expect it to be as abundant as PP; you have to rely on specialized channels and dedicated connections to source it.

Another key point of this small business is the term 'original color.' Why is specialty material expensive? Because it is used to make semiconductor test carriers, medical parts, and high-temperature insulation, which are very demanding regarding impurities, ion leaching, and appearance. Even with the same PEI sprue, if it is in its original color, translucent amber, and free of oil stains, its recycling price can be higher; if mixed with black impurities, contaminated with cutting fluid and oil, or if it's unclear whether it is PEI or PSU mixed together, its value is immediately halved and it can only be downgraded for lower-demand parts. Therefore, when collecting specialty materials, the first thing is not to ask the price but to check whether the materials are clean and separated. Ningbo Kelong has been in this business for many years: when collecting materials, they first look at the original color, then separate by grade, and only lastly discuss the price. The reasoning is here—the profit of specialty materials lies entirely in the sorting process.

Figure 1 High-temperature resistant special engineering plastics: PI film, PSU fittings, PEI rods and plates

The three can withstand high temperatures, but that doesn't mean they can be arbitrarily remelted.

When it comes to recycling special materials, many people think: since it's heat-resistant, just remelting it is fine. This is barely true for PEI and PSU, but completely wrong for PI. Although all three are 'high-temperature resistant,' their temperaments are very different, and the recycling methods cannot be generalized.

Let's start with PEI, which is the 'easiest to deal with' among the three. PEI is an amorphous thermoplastic; if the sprue is clean inside the factory, breaking it down, washing, and regranulating it can maintain performance quite well. Industry data has shown that for PEI recycled once under normal process control, the glass transition temperature only drops by 2 to 8°C compared to virgin material—virgin material is around 217°C, and after one recycling it’s around 213 to 218°C, almost unnoticeable. But repeated recycling is less forgiving: research shows that after five consecutive processing cycles, Tg gradually decreases, and with each reheating, mechanical properties and appearance are compromised. As for PSU, also an amorphous thermoplastic with a Tg of about 185°C, recycling from a clean sprue by regranulation can retain most of its performance, and glass fiber reinforcement makes it even more wear-resistant.

Back to where these materials are used, then you’ll understand why they are picky. PEI is used for semiconductor test carriers because it can repeatedly withstand temperatures around 170 to 180 degrees during testing without deforming, keeping the chips perfectly in place—if the dimensions shift, an entire batch of tests is ruined. PSU is used for medical devices and water treatment membranes because it can endure repeated high-temperature sterilization, resist acid and alkali corrosion, and is transparent so you can clearly see the liquid level. PI is used for flexible circuit boards and high-temperature insulation because it remains stable across a wide temperature range from over minus 200 to 400 degrees Celsius, whereas other materials would have melted or become brittle. Precisely because these materials are used in such "cannot fail" applications, they are especially cautious about recycled materials—not that they cannot use them, but they must use them with full understanding.

When it comes to PI, the approach changes. Most PIs are thermosetting or have a semi-crystalline structure and simply don't melt. The idea of cleaning them like PP and directly pelletizing is out of the question—they don't melt when heated; they only slowly decompose. Therefore, PI recycling doesn't follow the route of melting and re-pelletizing; it mostly involves physical grinding: turning panels, rods, and film scraps into fine powder, which can then be used as filler in other materials, or decomposed for recovery at high temperatures. In other words, PEI and PSU are "recycled pellets," while PI is more "recycled powder." Don’t try to apply the pelletizing approach to PI. If you don’t understand this and try to pelletize a bunch of PI scraps, the machine will jam immediately.

There's another common point that needs to be highlighted: all three are expensive, so the economics of recycling them is very sensitive. People don't care if recycling PP into granules saves a few cents per pound, but a pound of PEI scrap could be worth several pounds of ordinary material. Therefore, their recycling isn't based on large volume, but on being 'clean'—natural color, single type, no oil contamination, and sprues that others are eager to take; blackened, mixed-color, or oily pieces are hard to give away. The grading table below is divided according to the sources and forms of each of these three types.

LevelMain sourceKey indicatorsTypical uses
Recycling of PI film scrapsFPC cutting corners with PI filmHigh-temperature resistant insulation, with a wide temperature range of -269 to 400°CHigh-temperature insulation film, flexible circuit reinforcement
PI molded plastic/powder recyclingPI board rod CNC planing edges and cornersLong-term resistance above 300°C, suitable for grinding and recyclingHigh-temperature structural components, seals, wear-resistant parts
PSU injection molding grade recycledPSU injection molding clean gateTg about 185℃, long-term -100~175℃Medical devices, water treatment membranes, transparent chemical-resistant components
PSU Extrusion/Transparent Grade RecyclePSU extruded cornersTransparent and weather-resistant, resistant to inorganic acids, alkalis, and saltsTransparent fittings, insulating parts, food contact parts
PEI (ULTEM) natural-colored sprue recyclingPEI Injection Molding Gate / CNC ChipboardTg about 217℃ maintained, UL94 V-0Electronic connectors, semiconductor test fixtures
PEI glass fiber reinforced recycledIn-plant gate of fiber-reinforced PEIHigh strength and rigidity, dimensionally stableHigh-strength heat-resistant structural components

Explanation: PI/PSU/PEI are all special engineering plastics. Currently, recycling mainly refers to GB/T 40006.1 'Plastics — Recycled Plastics — Part 1: General Rules' and the corporate standards of various manufacturers. Most PI materials are thermosetting/semi-crystalline structures and cannot be re-melted into pellets, primarily being reused as powder, while amorphous thermoplastic PEI/PSU can be crushed and pelletized. The Tg, heat resistance, and other indicators in the table are summarized from publicly available industry information and manufacturers' technical data. For more grades and physical property parameters, refer to the manufacturers' official TDS.

Recycling special materials saves on price differences; what you can't gamble with are the key components.

Are specialty recycled materials cheap? They are cheap, but their cheapness is not the same as the cheapness of PP. PP is a direct cut in the price per ton, while specialty materials are more like 'new material is too expensive, so use some clean recycled material to bring down the cost'—you save on the price difference, but you can't risk it on critical components. That's how the accounting should be done.

Cost itemNew materialRegenerationDifference Explanation
Price per ton of materialVery talla bit lowerThe price difference for special materials is large, and using clean, natural-colored materials really saves.
Temperature Resistance / Tg RetentionBenchmarkRecycle several degrees at a timeRepeatedly reheating and accumulating further reductions, don't be greedy about the number of times
Strength and rigidityTallKeep the natural color of the sprueImpurities and mixed oil then decrease significantly
Source stabilityStableNear the factory water inlet/CNC chipboardThe quantity is small and the batch is limited, so materials must be secured in advance.
Medical/Semiconductor CertificationSufficient endorsement for new materialsRegeneration needs to be evaluated item by itemImplant-grade, ultra-clean level uses ordinary recycled materials
Comprehensive costBenchmarkChoosing the right part saves moneyBeing greedy and mixing things indiscriminately will cause problems

Taking this account into consideration, the boundary list below helps you determine whether the high-temperature parts you have can use recycled materials.

Suitable for recycling: clean natural PEI sprues for semiconductor test carriers, electronic connectors, and heat-resistant structural parts; PSU recycled material for transparent chemical-resistant parts; PI powder/molded material for recycling high-temperature insulation and wear-resistant parts.

For long-term high-load key stress-bearing parts, medical implants, and parts with extremely strict requirements for ion release and cleanliness: don't gamble with ordinary recycled materials; use new materials when new materials are needed.

Don't think about melting and re-pelletizing PI: it doesn't melt, it can only be ground into powder to be used as filler or re-pressed. Starting the machine with the idea of pelletizing will definitely jam it.

Don't be greedy with the amount: use a small proportion of special recycled material, mix it according to its purpose; if you mix too much, both strength and appearance will fail.

Make sure to recognize the clean, original quality: materials that are blackened, mixed colors, or contaminated with oil, no matter how cheap, should not be used in high-temperature parts.

Changing materials on semiconductor carriers saves money on scrap and maintains the precision of the carriers.

Let me give a typical scenario example. Ningbo Cologne New Materials Co., Ltd. has handled quite a lot in the specialty materials field. Below, we will reconstruct according to common situations in the industry.

There is a semiconductor test fixture factory in East China that mainly processes PEI (ULTEM) material. This material is expensive when new, and the CNC-milled chips and injection molding sprues in the workshop used to be piled in the corners and handled as waste for convenience. Later, when they did the math, they realized that the clean, natural-colored PEI chips thrown away each month were worth quite a lot. However, they were hesitant to recycle them themselves for fear of unstable performance, since the fixtures are repeatedly used in test environments of 170–180 degrees, and if the dimensions vary, the chips cannot be placed accurately.

Later, this factory discussed this matter with Kolon New Material. Kolon New Material didn’t quote a price first; instead, they asked about the intended use: whether the carriers would undergo long-term high-temperature testing or intermittent use, how strict the requirements were for dimensional accuracy and strength retention, and whether a small proportion of recycled material would be acceptable. After clarifying these points, their suggestion was: separately collect, crush, and wash the natural-colored, oil-free PEI sprues and shavings from the workshop, separate them by grade, supplement and dry them for single-use recycling, and mix a small proportion back into non-critical positioning carrier parts; for parts with critical positioning surfaces or parts subject to long-term high loads, continue using new material and don’t take risks. They also required measuring Tg and tensile strength for each batch, limiting the number of recycling cycles, and strictly forbidding repeated processing of the same batch.

The factory later turned recycling into workshop rules: natural PEI sprues are stored separately, ground separately, and recorded separately; CNC chips are cleaned on the same day and never mixed with other materials. After a year, most of the chips that used to be sold by weight as waste plastic returned to the production line, making the cost sheet look much better and the workshop corners much cleaner. The boss said that if he had known the scraps of special materials were so valuable, he wouldn't have carelessly thrown them away as trash in the past few years.

By doing this, scrap material is no longer thrown away as waste, effectively reducing costs, while the precision and yield of the components do not drop — because critical parts are always backed up with new material, and recycled material only covers the parts it is meant to. After working with specialty materials for a long time, one comes to realize: this field is not about who dares to use entirely recycled material, but about who can distinguish which parts can use recycled material and which must use new material. This is also why Ningbo Cologne New Materials Co., Ltd., when recycling PI/PSU/PEI, would rather use a small proportion to maintain original color and profitability than fill in with mixed-color material — the cost of specialty materials is saved at the edge where it matters, not in invisible areas.

When choosing recycled materials for high-temperature parts, first ask how much heat resistance is left.

Before selecting materials, first save the following application comparison to your phone and find the level according to the scenario. These three high-temperature nobles are indeed expensive in small quantities, but it's not a problem if used in the right place.

Application scenarioRecommendation LevelPrecautionsWhen to stop using
Semiconductor Test Fixtures/ConnectorsPEI Natural Color Sprue RecyclingObserve Tg and maintain intensityNew material for critical high-precision positioning parts
High-temperature insulation/wear-resistant structurePI Powder/Molding Plastic RecyclingReturn the ground powder for reuseDo not use it if you want to melt and regranulate
Transparent chemical-resistant/medical equipmentPSU RecyclingChemical Resistance and ComplianceAromatic hydrocarbon-resistant, halogenated hydrocarbon
Glass fiber reinforced heat-resistant partPEI Fiber-Reinforced RecycledCheck the fiberglass contentNo authentication identification
High-temperature film/insulationPI Film RegenerationCheck the thickness and insulationDo not use leftover membranes after consumption
Price-sensitive non-critical partsBlended recyclingsmall proportion mixingDo not use for high-load critical components

High-temperature resistant additives are expensive, but the sense of proportion in recycling them is even more precious—using the right amount saves a lot of money, while greedily adding too much ruins your reputation.

Recycled PI/PSU/PEI can save costs, but don't overuse it.

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

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