Application practice of nanocellulose in improving oxygen and water barrier properties in food cling film

1. Application background

During the circulation and storage of food, the continuous penetration of oxygen and water vapor is a key factor affecting the stability of food quality. The entry of oxygen will accelerate lipid oxidation, color change and flavor deterioration; the migration of water will cause fruits and vegetables to lose water and wilt, the surface of fresh meat will dry out, or the taste of cooked food will decrease.

As consumers' requirements for food safety and preservation effects continue to increase, food cling film not only needs to have basic coating and protective functions, but also needs to achieve synergistic improvements in However, the structure of traditional polymer cling film has problems such as large free volume and loose arrangement of molecular chains, which limits the space for improving its barrier properties.oxygen barrier and water barrier properties .

Based on this background, nanocellulose, as a natural material with high crystallinity and nanoscale structure, is introduced into the food cling film system to improve the internal microstructure of the film and enhance the overall barrier capability.

What is nanocellulose？

Cellulose nanofibers ( CNF) are ultrafine cellulose fibers made from wood. Wood pulp (papermaking raw material) produced through traditional papermaking technology is relaxed to the nanometer level. This is a new material derived from biomass, also known as nanocellulose.

CNF is as thin as a few nanometers, is considered transparent, has unique viscous properties, is light and strong, and has less deformation due to temperature changes, and is used in many fields.

● Nano = one millionth of the length of 1 millimeter

Process of producing nanocellulose CNF from wood pulp

1. The wood is crushed into small pieces and processed into wood chips (about 5cm wide and about 1cm thick)

2. Extract fiber from wood chips and make pulp in paper mill

3. The pulp is chemically treated to make it thinner and easier to loosen (chemical modification).

4. Apply high pressure to loosen wood fibers (pulp)

We chemically treat the pulp produced in the mill and introduce ionic functional groups into the cellulose, which forms wood fibers. The electrostatic repulsion of this functional group promotes nanoscale defibrillation of fibers while ensuring stable diffusion of elongated fibers in the range of a few nanometers (a few nanometers).

Fibers that are as thin as a few nanometers are thinner than the wavelength of visible light (400 nanometers to 700 nanometers), so they pass the light and become transparent.

2. The mechanism of action after the introduction of nanocellulose

Nanocellulose has the characteristics of small size, large specific surface area and high crystallinity. When it is evenly dispersed in the plastic wrap substrate, it can form a continuous and dense nanoscale network structure inside the film layer, which has a significant impact on the diffusion process of gas and moisture.

The specific performance is:

The highly crystalline regions of nanocellulose reduce the free volume inside the film

Network structure extends oxygen and water vapor transport paths

The diffusion process from changes ' straight-line penetration ' to ' zigzag detour '

The penetration rate is significantly reduced

This structural control function allows the film to simultaneously without significantly increasing its thickness.improve its oxygen and water barrier properties 。

3. Customer application requirements

Customers have put forward the following clear requirements in food packaging applications:

Significantly improve the oxygen and water barrier properties of plastic wrap

Delay food oxidation, discoloration and water loss

Maintain the original transparency and flexibility of the film

Do not change existing packaging equipment and usage habits

Comply with safety and environmental protection trends of food contact materials

4. Application plan implementation

In the existing food cling film production system, by rationally designing the addition method and dispersion process of nanocellulose, it can be evenly embedded in the film layer structure and form a stable composite system with the substrate.

The program focuses on controlling:

Uniform distribution of nanocellulose in the film layer

The balance between density and flexibility of film layer structure

Barrier performance improvement and processing performance compatibility

System optimization of barrier properties can be achieved without affecting film processing adaptability and performance.

5. Practical application effect performance

In actual packaging and storage tests, nanocellulose-enhanced food cling film showed obvious advantages:

The oxygen transmission rate is significantly reduced, and the food oxidation rate is significantly slowed down.

Water vapor transmission is effectively inhibited, and food moisture retention ability is enhanced.

Fruits and vegetables lose less weight during storage and look fresher

The taste stability of fresh and cooked food products has been significantly improved

The overall structure of the film is stable and not easily deformed or damaged during use.

6. Comparison of barrier and preservation effects

Contrast Dimensions	Traditional plastic wrap	Nanocellulose reinforced cling film
Oxygen barrier properties	generally	Significantly improved
Water blocking performance	weaker	Significantly enhanced
food freshness	Decay faster	last longer
shelf life stability	generally	Significant improvement
Comprehensive preservation effect	ordinary	Efficient and stable

Food plastic wrap added with nanocellulose

7. Case summary and application value

By introducing nanocellulose into food cling film and utilizing its high crystallinity and nano-network structure to regulate gas and moisture diffusion paths, the synergistic improvement of the oxygen and water blocking properties of the cling film has been successfully achieved. This solution effectively delays the food oxidation and water loss process without increasing the film thickness or changing the use method, and provides the food packaging industry with a mature application path that takes into account performance improvement, safety and sustainable development.

This case is suitable for various application scenarios such as fruits and vegetables, fresh food, cooked food and refrigerated food, and has good promotion value and industrialization potential.

( Schematic diagram of the three-dimensional network structure of nanocellulose )

Inquiry about nanocellulose

Nanjing Tianlu Nanotechnology Co., Ltd. ，Marketing Department , Nanocellulose Promotion Office

Address: Room 301, Building 2, Phase 3, No. 1, Yuepu Yunchuang Center, No. 6 Shuige Road, Jiangning District

Telephone:18061643560