EVOH副牌,食品包装膜里那层看不见的氧气墙

产品中心 发布时间: 2026-09-13 2559 阅读

"The barrier data for this batch of films is incorrect, the oxygen transmission rate has doubled, and the customer wants to return the product." "

" Impossible, EVOH uses genuine brand, and each layer thickness is made according to tolerances. "

" The genuine brand is genuine, but have you confirmed the ethylene content in this batch of EVOH? Send it for testing. "

Three days later, the test report came out—the ethylene content in the EVOH layer dropped from the advertised 32% to 38%, and the barrier performance dropped sharply. Manufacturers making food packaging films understand this scenario: if there is a problem with the EVOH layer, the shelf life promise of the entire composite film will collapse. What is

EVOH, and why is food packaging inseparable from its

EVOH, ethylene-vinyl alcohol copolymer? Its molecular chain consists of two segments: one is ethylene, providing processing and water resistance; The other is vinyl alcohol, providing oxygen barrier. The ratio of these two segments—that is, ethylene content—directly determines EVOH's character: low ethylene content means good barrier but poor water resistance; High ethylene content means good water resistance but reduced barrier properties.

Why can't food packaging do without EVOH? Because its oxygen transmittance (OTR) can reach 0.03 cc/m²·day, lower than most plastics. Installed in the middle layer of composite film—typical structures are PE/EVOH/PE—oxygen can't penetrate, so sausages, cheese, and ketchup inside can be stored for half a year without oxidizing. This film is as thin as just over ten microns, but it's the lifeblood of the entire packaging shelf life.

The global landscape is highly concentrated. Kuraray is the pioneer and leader in EVOH, with the EVAL brand accounting for 30-40% of global capacity; Japan's Nippon Gohsei (a subsidiary of Mitsubishi Chemicals) owns Soarnol for over 20%; Taiwan's Changchun Chemical is the third large-scale supplier. Together, these three account for the vast majority of global EVOH capacity. This is a market where two oligos plus one strong player is hard for newcomers to break into.

Where does the sub-brand come from, and how do you distinguish it from recycled materials

EVOH The definition remains unchanged: batches of the same manufacturer and grade that do not fully meet factory inspection standards. But EVOH has a special feature—its key indicator is ethylene content. If the ethylene content differs by two percentage points, the barrier performance changes by a whole level. The secondary brand usually has a slight drift in ethylene content near the nominal value, or a slight deviation in the melting index.

Four main sources: unit start-stop starting and tail materials, grade switching transition materials, process fluctuation batches, and auxiliary line tailings. The main source of EVOH's secondary brands is grade switching—from low ethylene content to high ethylene content, with ethylene content in the intermediate transition section fluctuating, but the molecular chains remain EVOH, so the barrier performance remains.

Boundary with recycled materials: EVOH secondary brands are original original polymer particles. Recycled materials are membrane edge scraps re-pelletized—EVOH is a highly polar material, which easily absorbs moisture and degrades during recovery, causing significant loss in barrier performance. If food packaging films use recycled EVOH, the shelf life promise is directly discounted, causing food oxidation and flavor deterioration. The compensation is not something a ton of material can cover.

Kuraray: EVAL, the defining of the EVOH category .

Kuraray was the first in the world to commercialize EVOH in 1972, and the EVAL brand has been in the industry for fifty years. It has facilities in Japan, the US, and Belgium, with a global market share between 30% and 40% (varies by diameter). EVAL grades are classified by ethylene content—typically three mainstream levels: 32mol%, 38mol%, and 44mol%. The higher the value, the more water resistance; the lower the value, the more barrier.

For factories making food packaging films, the most familiar is the 32mol% range—good barrier properties, suitable for dry food packaging. If you need boil-resistant packaging, use the 38mol% or 44mol% range—good water resistance, can't block after high-temperature cooking. The source of EVAL secondary brands mainly comes from grad switching transition materials in Japanese and Belgian units, with slight fluctuations in ethylene content, for example, nominal 32% but actual measured 33.5%—this floating level is more than enough for regular food film.

The key to choosing EVAL secondary brands is the ethylene content locked in. If your composite film structure is designed at 32% and you get a batch of 38% secondary brands tested at 38%, the barrier resistance drops by one level and shelf life is shortened. Test the ethylene content before receiving and match it with your membrane structure design. Packaging is divided into large and small packages. Large packages are suitable for continuous feeding on multi-layer co-extrusion production lines, while small packages are suitable for prototyping.

Japan Synthetic Chemical: Soarnol, the second pole after Kuraray

Nippon Gohsei, a subsidiary of Mitsubishi Chemical, is the second pole in the EVOH market. It has facilities in Japan, and its product grading system is similar to Kuraray's, classified by ethylene content. Soarnol is characterized by good processability—its thermal stability during multi-layer co-extrusion is slightly better than EVAL, and it is less likely to remain in the screw for long and discolor.

Soarnol sub-brand, mainly comes from batch fluctuations in Japanese equipment. Factories making food packaging films use Soarnol sub-brand instead of genuine EVAL brand, which lowers costs significantly and has little difference in barrier performance at the same ethylene content level. One point to note: although both Soarnol and EVAL are EVOH, their molecular chain sequence distribution differs slightly—the interlayer adhesion of composite films needs to be re-verified, so do not directly apply Soarnol based on EVAL's process parameters.

Changchun Chemical: Taiwan Power, the third large-scale supplier

Changchun Petrochemical is a Taiwanese petrochemical company, and EVOH is one of its product portfolios. Its EVOH grade mainly targets packaging applications, priced slightly lower than Kuraray and Japanese Synthetic Chemical, and holds a certain market share in Asia.

Changchun Chemical's subbrand mainly comes from grade switching transition materials for Asian units. Factories making ordinary food packaging film treat it as an economical choice—the barrier performance meets food packaging requirements, and the price is lower than the two Japanese brands. But note that Changchun Chemical's EVOH in high-barrier demand scenarios—such as meat product packaging requiring long shelf life—still lags behind Kuraray in batch stability. For high-demand films, it's best to choose EVAL or Soarnol genuine or carefully selected secondary brands.

Three pitfalls, don't bet on barrier film

First pitfall: ethylene content doesn't match the membrane structure. This is the most fatal pitfall of EVOH secondary brands. Your composite film was designed for 32% barrier strength, but a batch of 38% secondary brands lowered the barrier by one level—the shelf life of dry food shortened from six months to three months. Test ethylene content before receiving goods, don't just look at the packaging label.

Second pitfall: Buying recycled material as a secondary brand. EVOH recycled material has more serious moisture absorption and degradation issues than other polyolefins—the hydroxyl groups in the molecular chain easily absorb water, and after secondary granulation, their barrier performance drops significantly. If a factory making food packaging films uses recycled EVOH, customers' food will oxidize and lose flavor within two months, and returns and claims will be common. During sample inspection, check the appearance of the pellets—the recycled pellets are yellowish and uneven in size; The secondary brand is the original factory's original particles, and their appearance is basically identical to the genuine brand

Third pitfall: ignoring interlayer adhesion. EVOH is a polar material and requires an adhesive layer between it and the PE layer. Different grades of EVOH have slightly different surface tensions; if the sub-brand has a floating molecular weight, interlayer adhesion may decrease—composite film peeling and barrier layer failure. Perform peel strength tests before installation; only after meeting interlayer viscosity standards can you proceed with bulk orders.

Cologne warehouse stock | EVOH partners

Main recommended brands: Kuraray, Japan Synthetic Chemical, Changchun Chemical.

Main grades: EVAL (32/38/44mol%), Soarnol, Changchun Chemical EVOH.

Packaging Specifications: Small sub-brand and boxed sub-brand use small packaging; large package/ton sub-label uses ton bags, with packaging and stock according to workshop usage.

Warehouse Stock: EVOH warehouse stock is usually around 4000 tons, with small sub-brand stocks at 600-900 tons, sub-brand containers at 250-450 tons, and large packages/ton stocks at 2650-3150 tons.

Supply Assurance: Test orders come with goods, COA goes hand in hand with goods.

Selection tips and a Jiaxing case

Lock in ethylene content, measure melting index, match your membrane structure design, EVOH sub-brand arrives at the factory—barrier data is stable, shelf life doesn't shrink, composite film mass production is done in one go.

Jiaxing has a client making snack food packaging films. Previously, they used Kuraray's genuine 32mol% EVAL as an intermediate barrier layer, but material costs remained high. Later, they tested a batch of EVAL 32mol% sub-brands: ethylene content measured at 33.2% (rated 32%), melting index measured at 3.8 (rated 3.6), both within the allowed deviations. Machine-made PE/EOH/PE three-layer co-extruded film, with an oxygen transmittance of 0.05 cc/m²·day measured for oxygen transmittance, very close to the genuine film's 0.04. The customer's six-month shelf life test met the standard. Material cost per ton dropped by over 1,000, saving over 200,000 yuan in the annual photobarrier membrane segment.

This is how EVOH sub-brand is used—not all packaging needs genuine brand. Six months is enough for the packaging window for snack foods, and the fluctuating ethylene content on the sub-brand can be absorbed within the design allowance. Ningbo Kelong New Materials Co., Ltd. has been making imported EVOH sub-brand materials for years. Suppliers from Kuraray, Japan Synthetic Chemical, and Changchun Chemical are all involved, and they receive many food barrier film projects every year.

Who hasn't been tricked by EVOH for packaging film, food packaging, or multi-layer co-extruded products? Is it that the ethylene content is insufficient, causing shelf life to shrink? Or is it that recycled material is passing off as a secondary brand, causing delamination and warping? Or is the interlayer adhesion insufficient, and the laminated film delamination?

Data and Data Source

Kuraray EVAL Product Technical Information (Kuraray Official Website, kuraray.com, Verification Date: 2026-09-14)

• Japan Synthetic Chemical Soarnol Product Series Public Information (Nippon Gohsei/Mitsubishi Chemical, Verification Date: 2026-09-14)

• Dataintelo Global EVOH Market Report (dataintelo.com, verified on 2026-09-14)

• Sunkey Packaging EVOH Industry Analysis Article (sunkeypackaging.com, verified on 2026-09-14)

• PW Consulting Global EVOH Packaging Market Report (pmarketresearch.com, verified on 2026-09-14).

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