全球每三支新冠抗原检测卡的透明外壳,就有一支藏着这种塑料的副牌

产品中心 发布时间: 2026-09-12 3319 阅读

Let's start with a number.

In the 2024 global medical diagnostic consumables market, the factories making antigen detection cards, ELISA microplates, and pre-filled syringe piston rods all rely on a type of transparent plastic. It's not called PC, not PMMA, nor PS, but it's called COC, a cycloolefin copolymer.

The total global production capacity for this thing is only 80,000 to 90,000 tons per year. It doesn't sound like much, but it combines transparency, low precipitation, sterilization resistance, and biocompatibility. If PC and PMMA want to be medical-grade, they have to make way for it.

Here's the problem: genuine COC sells for over 200,000 yuan per ton, and small manufacturers don't dare touch it; Many of the "cheap COCs" circulating on the market are made from recycled materials; if the precipitated material exceeds the standard, the entire batch of diagnostic cards goes straight into hazardous waste.

Genuine products are expensive, recycled materials are risky—where is the middle path? The answer is sub-brands from major manufacturers. Today's article explains the global landscape of COC, the three leading manufacturers, and whether sub-brands can actually be used, all at once. What kind of material is

COC, and why is the medical community rushing to use it?

To put it plainly, COC is a transparent engineering plastic formed by copolymerizing ethylene and cyclic monomers (like bornoleene) into the same polymer system.

It has three hidden abilities. First, its transmittance is on par with PMMA, but its birefringence is low, so it doesn't fade in optical and diagnostic devices. Second, it's resistant to gamma rays and ethylene oxide. PC turns yellow after a single gamma test, but COC doesn't. Third, the precipitates are extremely low, making it a consumable for in vitro diagnostics and won't mix with reagents.

So the transparent covers for antigen test cards, PCR octa-tube tubes, and pre-filled syringes are increasingly made with COC.

But it's expensive. It's not because of cutting corners, but because there are factories that can make these products on one hand in the world.

The global COC companies are basically these three major foreign companies .

is ranked by capacity, and global COC/capacity is monopolized by a few Japanese and German companies, with CR3 accounting for over 90%. The following three companies are the main suppliers you can't avoid.

First, TOPAS Advanced Polymers. The origin of this factory needs to be clarified: it was originally a team from Ticona, a subsidiary of Celanese, working on COC in Germany, under the brand TOPAS. Around 2020, Japan's Polyplastics brought this COC business under its umbrella. Now, TOPAS Advanced Polymers GmbH is a wholly-owned subsidiary of TOPAS Plastics, with its production base in Germany. Its COC capacity is about 35,000 tons per year, accounting for about 40% of the global market, and it is recognized as the global leader in COC routes. In medical prefilled syringes and diagnostic consumables, TOPAS is widely recognized.

The second company, Mitsui Chemicals. Japan's Mitsui Chemicals takes a different copolymerization route, with a brand called APEL. The APEL series is characterized by a wide variety of grades, ranging from low heat resistance to high heat resistance, with corresponding grades for lenses and medical packaging. Mitsui accounts for about 7% to 10% of the COC/COC family's capacity. Not a large but full range, and high-end optics and medical devices are often mentioned.

The third company, JSR (Japan Synthetic Rubber). JSR originally made synthetic rubber and photoresist, and its COC/COP material made using the open-loop polymerization route is called Arton. Arton is characterized by transparency, heat resistance, and chemical resistance, and is skilled in making optical films and precision medical devices. Its production capacity is not large, about 5,000 tons per year, but it is highly recognizable in high-end film materials and microstructural components.

Zeon's Zeonex/Zeonor set is, strictly speaking, an open-loop polymerization followed by hydrogenation via the COP route. It is closely related to COC but not on the same process; the article will focus on COP in detail later.

Subbrand, let's break down the concept first

When many people hear "subbrand," they think of defective products, scraps, recycled and re-pelletized materials. This is a big misunderstanding.

The precise definition of a secondary brand is: in polymerized products from the same manufacturer and grade, some technical indicators during factory inspection do not fully match the lower edge of the genuine brand. It's not another batch of material, but the part of the same batch that has been tested for a breath of the same quality.

Where does it come from? There are just four gaps. First, the tail material at the end of the unit when it starts and stops; the polymerization reaction should be stable at the start and close when it is about to end, so the material indicators at both ends are floating. Second, the transition material at grade switching, where the previous grade has just been cut, and remnants from the previous grade remain in the barrel. Third, the batches in normal production where certain indicators such as melting finger, hue, light transmission, and ash content have slight shifts. Fourth, the tail material from the secondary line.

Key properties: They are still original original polymer particles, with molecular structure identical to genuine ones, only minor fluctuations in some indicators. They are not pelletized from waste plastic and have not experienced a second heat cycle.

Boundaries must be clear: genuine brands meet all indicators and have stable batches; secondary brands have slight deviations in certain indicators and coexisting base materials; recycled or sprue material is recycled scraps from the product and have already experienced one heat history; recycled materials are recycled waste plastics with large performance fluctuations. These four are completely different in price and usage.

TOPAS secondary brands are suitable for what kind of

TOPAS secondary brands mainly float on two indicators: first, light transmittance is slightly lower than the genuine brand; second, the hue and yellowness index slightly fluctuate.

This kind of secondary brand can't be used for optical lenses requiring high transmittance, but it's more than enough for the transparent cover plate of antigen test cards, the frame of ELISA plates, and non-critical components of reagent tubes. Think carefully — these items need to be "visible, non-precipitated, sterilizable," not to compare resolution with lenses.

TOPAS secondary brands mostly come in large packages, entering the silos of modification and product factories. When poured out, they are almost indistinguishable from the genuine brand, only the secondary label on the original packaging.

Mitsui APEL secondary brand, how to choose

Mitsui APEL secondary brand, characterized by multiple grades and a bit of fluttering and variation. Some grades have slightly floating melt fingers, while others withstand temperatures about 35 degrees lower.

When choosing APEL secondary brands, first look at which indicators your parts are sensitive to. For injection-molded thin-walled parts, check if the melt fingers match the mold flow; For parts requiring temperature resistance, check where the lower edge of the thermal deformation temperature lies. The advantage of APEL secondary brands is that their molecular chains share the same origin as the genuine brand, so you don't need to change the formula after switching, just test the sensitive indicators once more.

JSR Arton's secondary brand is small in quantity but refined

Arton with limited production capacity, and even more limited outflow, with limited supply on the market. Its secondary brand is mostly used for internal coatings of optical films and non-critical layers of micro flow control components. When encountering Arton secondary brands, first ask which grade it is, whether it is translucent or heat-resistant, and don't use it to target high-end lenses.

Avoid pitfalls when choosing secondary brands: three things to avoid

First, recognize the brand, not the "brand." For the same factory, sub-brands of different grades cannot be mixed; what you want is the one that matches the original formula.

Second, verify the indicators before signing. COC especially requires attention on light transmission, yellowness, and precipitates. These three must be tested at the factory, not just based on the seller's verbal guarantees.

Third, packaging comes in different sizes. COC sub-brands come in both large and small packages on the market. Small packages are suitable for sampling and small batch trial production, while large packages are suitable for mass production to dilute costs. Don't compare small packaging materials by the price of large packages, and don't do the opposite.

Cologne Warehouse In-stock | COC Temperature and Humidity

Main Recommended Brands: TOPAS Advanced Polymers (under Baoli), Mitsui Chemicals (Japan), JSR

Main Grades: TOPAS, APEL, Arton

Packaging Specifications: Original factory packaging, available in both large and small packaging; Small sub-brand packages, boxed sub-brands, large packages/ton materials are stacked in tiers, stocked according to batch stock

warehouse stock; COC sub-brand warehouse has about 5,000 tons in stock

Spot Details: Small-package secondary brand stock 800-1000 tons, Boxed secondary brand stock 300-500 tons, Large-bag/ton-bag stock 3500-3900 tons

Supply Assurance: Test first, then sign; measure the key indicators before entering the factory, and then sign the contract based on the intended use

Selection Mnemonic and a Real Case

In the end, COC secondary brand is the same-line output as the original brand—produced on the same set of metallocene catalyst polymerization equipment, just the light transmittance score differs by a few hundredths of a percent.

When choosing COC secondary brand, remember these five points: first, check if the application is sensitive; second, see which company and which grade it corresponds to; third, verify light transmittance, yellowness, and extractables; fourth, choose large or small packaging based on volume; fifth, keep batch samples for traceability.

Here’s a case. A factory in Anshan making in vitro diagnostic consumables used to make transparent covers for antigen test cards, always using the original TOPAS, costing over 200,000 RMB per ton—costs were hard to reduce. They tried a batch of domestic transparent material, but it was returned due to excessive extractables. Later, we provided them with a secondary brand of the same grade as TOPAS, with light transmittance differing by only a few hundredths of a percent, yellowness within a controllable range, and extractables and sterilization adaptability consistent with the original. After switching, the cost per piece dropped significantly, first-pass customer acceptance for the covers was achieved, and yield remained above 95%.

This is the value of the secondary brand—not buying cheap, but buying "same source, sufficient, and traceable." Ningbo Kelong New Materials Co., Ltd. has been making imported secondary brands for many years. For niche, high-transparency materials like COC and COP, they handle many similar cases each year. Simply put, they help lock in light transmittance and extractables before mass production.

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