EVALTM
Overview
In 1972, Kuraray became the first in the world to develop and commercialize EVALTM, 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), EVALTM 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 EVALTM equates to the gas barrier capabilities of a 10-meter wall made of LDPE. Even a thin layer of EVALTM can significantly enhance the barrier properties of composite layers. Incorporating EVALTM in multilayered designs presents a transparent, lightweight, and robust alternative to traditional materials like glass and metal.
Examples
Food packaging materials, medical packaging materials, automotive plastic fuel tanks, under-floor heating pipes, containers for agrochemicals, soil fumigating film, vacuum insulation panels, districted energy pipes, etc.
- Gas barrier properties
Excellent barrier properties against the permeation of gases including oxygen - Solvent/chemical substances barrier
Blocks solvents and chemical substances - Aroma retention
Excellent barrier for flavor and aroma preservation
- Transparency
Transparent package for content visibility - Chemical resistance
Minimal absorption of solvents - Low thermal conductivity
Low thermal conductivity compared with aluminum foil
Molecular structure of EVALTM resin – EVALTM 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. EVALTM 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 EVALTM resin – We have developed different types of EVALTM resin. Each type offers different useful characteristics, based on the ethylene mol% content.
EVALTM M type
This type has the lowest ethylene content available; it provides the highest barrier for automotive and flexible applications.
EVALTM L type
This type has a very low ethylene content and is suitable as an ultra-high barrier in flexible, bottle and sheet applications.
EVALTM 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.
EVALTM J Type
This type offers superior thermoforming performances and can be used for deep-draw or sensitive sheet-based applications.
EVALTM 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.
EVALTM E type
This type has a higher ethylene content that allows for greater flexibility and even easier processing.
EVALTM G type
This type has the highest ethylene content, making it the best candidate among standard types of EVALTM 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. ×ばつ65%RH, ISO14663-2 annex C 5. 210oC, 2,160 g
Further information about EVALTM