Overview
In 1972, Kuraray became the first in the world to develop and commercialize EVAL™, an ethylene vinyl alcohol copolymer (EVOH) resin. Renowned for its highest level of gas barrier properties among plastics (blocking out oxygen and preventing the spoiling of contents), EVAL™ is used widely in food packaging containers. In recent years, it has also gained attention as a gas barrier material that meets recycling standards for packaging materials. Applications are expanding, such as for automobile plastic fuel tanks and vacuum insulation panels for refrigerators.
A mere 1mm thickness of EVAL™ equates to the gas barrier capabilities of a 10-meter wall made of LDPE. Even a thin layer of EVAL™ can significantly enhance the barrier properties of composite layers. Incorporating EVAL™ in multilayered designs presents a transparent, lightweight, and robust alternative to traditional materials like glass and metal.
Examples
Molecular structure of EVAL™ resin – EVAL™ is a random copolymer of ethylene and vinyl alcohol. It’s a crystalline polymer that has a molecular structure, as represented by the formula on the right. EVAL™ resin combines the humidity resistance and easy processing of ethylene with the exceptional gas barrier and resistance to organic solvents of vinyl alcohol.
Available types of EVAL™ resin – We have developed different types of EVAL™ resin. Each type offers different useful characteristics, based on the ethylene mol% content.
EVAL™ M type
This type has the lowest ethylene content available; it provides the highest barrier for automotive and flexible applications.
EVAL™ L type
This type has a very low ethylene content and is suitable as an ultra-high barrier in flexible, bottle and sheet applications.
EVAL™ F type
This type offers superior barrier performance with long-term process stability and is widely used as the standard grade for flexible, automotive, bottle and tube applications. Specific versions exist for coating and pipe applications.
EVAL™ J Type
This type offers superior thermoforming performances and can be used for deep-draw or sensitive sheet-based applications.
EVAL™ H type
This type combines high-barrier properties to long-term stability and thermoformability. The higher ethylene content allows easier processing and longer running times on older co-extrusion equipment, especially for blown flexible structures.
EVAL™ E type
This type has a higher ethylene content that allows for greater flexibility and even easier processing.
EVAL™ G type
This type has the highest ethylene content, making it the best candidate among standard types of EVAL™ types for stretch and shrink film applications.
| Grade | Ethylene content (mol%) | Density1 (g/cm3) | MFR2 (g/10 min) | Melting point (ºC) | Glass transition point3 (ºC) | Oxygen transmission rate4 (cm3・20μm/m3・day・atm) | Applications |
|---|---|---|---|---|---|---|---|
| L171B | 27 | 1.21 | 4.05 | 190 | 63 | 0.1 | High barriers |
| F101B | 32 | 1.19 | 1.6 | 183 | 60 | 0.3 | Fuel tanks, bottles, tubes |
| F171B | 32 | 1.19 | 1.6 | 183 | 60 | 0.3 | Bottles, sheets, film, tubes |
| H171B | 38 | 1.17 | 1.7 | 172 | 56 | 0.7 | Bottles, sheets, film, tubes |
| E105B | 44 | 1.14 | 5.5 | 165 | 53 | 1.9 | Sheets, film, tubes |
| G156B | 48 | 1.12 | 6.4 | 157 | 50 | 3.7 | Stretch film, shrink film |
1. 20ºC 2. 190ºC, 2,160 g 3. Dry 4. 20ºC×65%RH, ISO14663-2 annex C 5. 210ºC, 2,160 g
Further information about EVAL™
